3,050 Matching Annotations
  1. Apr 2018
    1. stop codon

      A stop codon (or termination codon) is a series of three nucleotides that stops the translation process.

      It works by binding special proteins called "release factors." When these release factors reach the ribosome (the site of protein translation), they cause the new amino acid chain to separate from the ribosome, stopping translation.

    2. pro-band

      The term "pro-band" is used to refer to the patient being studied in biomedical research, especially research on genetics.

    3. These transcriptional effects suggest that the homozygous deletions in autism patients may preferentially involve activity-regulated genes, either mutating their coding sequence (e.g., DIA1) or potentially affecting conserved DNA sequences (NHE9, PCDH10) that may be critical for proper transcriptional regulation.

      The different ways that homozygous deletions affect the transcription of the three genes here suggests that abnormalities in neural-activity regulated genes may play a large role in autism.

    4. Moreover, a separate screen using RNAi knock-down of NPAS4, a transcription factor activated in response to depolarization, showed that NHE9 was one of 292 out of 22,407 cDNAs (1.3%) whose transcription was significantly altered (in this case, increased) (Fig. 3D) (22), although NHE9 expression was not detectably altered by membrane depolarization alone

      Unlike c3orf58 and PCDH10, expression of NHE9 was not significantly altered by changes in neural activity alone. However, NHE9 is among a small number of genes whose transcription was altered when the neural-activity regulated transcription factor NPAS4 was inhibited.

    5. binomial test

      A statistical measure of the probability that experimental results are due to chance. It is calculated by looking at the difference between the observed (experimental) results and the expected results (i.e. the results that would be expected if only chance were involved).

      The results of the test are reported as a P value, which is a probability. In general, a P of less than 0.05 means that the results of an experiment are statistically significant (and not a result of chance).

    6. transcriptional target of MEF2

      MEF2 RNAi did not increase transcription of PCDH10 as much as it did c3orf58.

      However, a fusion protein that contains MEF2 greatly increased transcription. This suggests that, even though MEF2 alone did not increase transcription, PCDH10 is a target of MEF2.

    7. PCDH10

      PCDH10 is a potential tumor suppressor protein. Abnormalities in PCDH10 have been found in many human tumor cells.

    8. forward screen

      A "forward" screen is used to identify the mutation(s) that leads to a given phenotype.

      A "reverse" screen is used to identify the resulting phenotype from a given mutation.

    9. We propose renaming this gene DIA1 (deleted in autism-1)

      The authors propose renaming c3orf58 to deleted in autism-1 (DIA1) because they found evidence that it was causative of autism in patient AU-3101.

      Genes are commonly renamed from "generic" names such as c3orf58 to more specific names that provide information about their function. Because there is no formal regulation of gene names, many genes have misleading names or multiple names.

    10. which suggests that c3orf58 may be a direct or indirect MEF2 target

      When the authors prevented MEF2 expression, they saw a corresponding inhibition of c3orf58 expression. This suggests that MEF2 either directly or indirectly mediates transcription of c3orf58.

    11. MEF2 transcription factor

      The myocyte enhancer factor 2 (MEF2) transcription factor is important to cell differentiation and embryonic development.

    12. RNA interference (RNAi) knock-down

      A biological pathway, found in many eukaryotes, in which RNA molecules inhibit gene expression. This is usually caused by the destruction of certain mRNA molecules.

      This pathway is used by researchers to increase or decrease the activity of genes of interest.

    13. neuronal membrane depolarization by elevated KCl

      This technique is used to study enhanced neuronal activity that may result from changes in gene expression.

      Elevated KCl (an increase in potassium outside the cell) results in a sustained depolarized state in three ways:

      1. Normally, potassium ions flow out of the cell, resulting in hyperpolarization. Elevated KCl outside the cell disrupts this gradient and slows the outward flow of potassium. At the same time potassium ions are flowing out of the cell, sodium ions are flowing into the cell. The flow of sodium ions into the cell does not slow down.
      2. The increase in the cell's membrane potential (the difference in charge on one side of the membrane versus the other) causes sodium channels to open. This allows more sodium ions into the cell and results in further depolarization.
      3. Partial activation of sodium ion channels prevents the neuron from triggering a full action potential.
    14. “neural activity–regulated” genes

      Genes that are "activated" by neural activity will typically be transcribed more following a depolarization event (i.e., an action potential).

    15. transcriptome

      The portion of a cell's DNA that is transcribed. The transcriptome can be identified by looking at all of the mRNA in a cell.

    16. blind to the genetic study

      To increase the reliability of the results, the researchers may have removed information identifying samples as "experimental" or "control." This can decrease bias in the analysis of results.

    17. hippocampal neurons

      The hippocampus is a major component of the human brain and those of other vertebrates. It is part of the limbic system and has a crucial role in the consolidation of information, including short- and long-term memory and spatial navigation.

      Rat and mouse hippocampal neurons are widely used in neurobiological studies. By isolating and growing individual neurons, researchers are able to analyze properties related to cellular trafficking, cellular structure, and individual protein localization.

    18. microarray screens

      An array is a grid of DNA samples that is used to identify and map genes.

      In this experimental setup, the cDNA derived from the mRNA of known genes is immobilized. The expression pattern is then compared to the expression pattern of a gene responsible for a disease.


    19. Neuronal activity induces a set of transcription factors (including MEF2, NPAS4, CREB, EGR, SRF, and others) with time courses of minutes to hours, and these transcription factors induce or repress specific target genes that mediate synaptic development and plasticity

      A significant number of the genes identified by the authors in this study were transcription factors that are involved in the growth and development of the brain.

    20. independently identified

      Because the three genes were identified by independent screens, it increases the reliability of the authors' conclusions.

    21. screens

      A technique used to detect a mutation or abnormality and provide important information on its function. In this case, the authors screened for genes associated with autism.

      There are many different types of screens depending on a researcher's needs, and they are widely used in scientific research.

    22. Smaller deletions (also unique to the individual family) (table S5) were closest to CNTN3, encoding BIG-1, an immunogloglobulin super-family protein that stimulates axon outgrowth (32); RNF8, encoding a RING finger protein that acts as a ubiquitin ligase and transcriptional co-activator (33); and SCN7A (amid a cluster of voltage-gated sodium channels that also includes SCN1A, SCN2A, SCN3A, and SCN9A) on 2q

      The authors found several smaller deletions in genes that are involved in the growth and development of the brain.

      The authors point out that further evidence is needed to say these genes are causative of autism. However, they suggest that several of them are likely to be (specifically the larger deletions).

    23. A second >300 kbp, linked, homozygous deletion (again not present in >2000 individuals other than this family) is closest to PCDH10 on 4q28 (Fig. 2 and table S5), which encodes a cadherin superfamily protein essential for normal forebrain axon outgrowth

      Another deletion the authors found in patient AU-3101 is in a gene that codes for a protein involved in the growth of neurons.

    24. previously reported to have been disrupted in a pedigree with a developmental neuropsychiatric disorder and mild mental retardation

      Disrupted NHE9 has been found in a family with a developmental neuropsychiatric disorder and mild intellectual disability.

      The fact that disrupted NHE9 has been found in multiple patients with neuropsychiatric disorders suggests it may be a cause of these.

    25. transcription

      The process of "reading" DNA to create mRNA, which then exits the cell nucleus to eventually be translated into a protein. This is the first step in protein synthesis.

    26. The deletion completely removes c3orf58, which encodes an uncharacterized protein with a signal peptide that localizes to the Golgi (28). Moreover, the deletion is near the 5′ region of NHE9, such that only 60 to 85 kbp upstream

      The deletion in patient AU-3101 removes c3orf58, which codes for a protein in the Golgi apparatus.

      The deletion also removes part of the transcription initiation site for NHE9.

    27. hemizygous

      The deletion is homozygous (present on both chromosomes) in the boy, but present on only one chromosome from each parent.

      Thus, the boy inherited the deletion from both parents.

    28. we were surprised to see that several consanguineous pedigrees showed large, rare, inherited homozygous deletions within linked regions, some of which are very likely causative mutations

      Although the authors did not sequence all linked regions (because of the time and cost associated with sequencing such large amounts of genetic material), they were surprised to find that several of the consanguineous families had rare inherited deletions.

      The authors suggest that these large deletions may contribute to autism.

    29. two families shared linkage to an overlapping region of chromosome 2q (AU-4500, lod = 2.41, and AU-4200, lod = 1.81) that has been previously implicated in other autism linkage studies

      Only two families showed the same abnormality, in chromosome 2q. This abnormality has been previously found to contribute to autism.

    30. Potentially linked loci were generally nonoverlapping between families, consistent with genetic heterogeneity

      The results of the authors' homozygosity mapping showed that there is considerable diversity between different consanguineous autism families. They also found that the abnormalities in the chromosomes of patients with autism were not shared between families.

      Taken together, these results suggest multiple genetic origins for autism.

    31. The relatively reduced M/F ratio of affected children and the reduced rate of linked de novo CNVs in the consanguineous sample (not significantly different from rates in control) both suggest that consanguineous pedigrees with autism are enriched for autosomal recessive causes similar to other congenital neurological disorders in consanguineous populations

      The higher proportion of affected women and the reduced rate of de novo CNVs in the consanguineous sample from this study both suggest a higher frequency of autosomal recessive causes for autism (and other neurological disorders) in consanguineous families.

    32. A large study, using identical BAC arrays run in the same lab as our study, found 5.6% (84 of 1500) of patients referred to Signature Genomics with de novo or pathogenic CNVs (chi-square = 3.052, df = 1, P < 0.05) (25). The HMCA rate of de novo CNVs was similar to previously reported rates in multiplex pedigrees with autism [1.28% in the HMCA versus 2.6%, or 2 of 77, in multiplex autism (6), chi-square = 0.557, df = 1, P = 0.22] and in controls [1.28% HMCA versus 1.0%, or 2 of 196, in control subjects (6), chi-square = 0.001, df = 1, P = 0.49], despite the fact that the 500K platform used here has significantly higher coverage

      Here, the authors compare their findings to other studies of de novo CNVs. They show that their results are similar to previous studies (such as Sebat et al.) that established the detection of de novo CNVs as a way to identify genes linked to autism.

    33. overall rates of de novo CNVs that segregated with ASD were 0% in consanguineous multiplex (0 of 42 patients) and 1.9% in consanguineous simplex families (1 of 52 patients), which were considerably lower than reported for nonconsanguineous families

      The data showed that de novo CNVs were much less frequent in consanguineous families (both simplex and multiplex) and the amount of inherited CNVs was high.

      As stated above, the low rate of de novo CNVs that segregate with disease suggests that inherited factors have a larger role.

    34. single-nucleotide polymorphism (SNP)

      A variation of a single nucleotide in a DNA sequence. When less than 1% of a population carries the nucleotide at this position, this variation is classified as a SNP. Some SNPs are associated with certain diseases.

    35. two sensitive methods for detecting them

      Both the single nucleotide polymorphism array and BAC Comparative Genomic Hybridization arrays are used to detect the number of copies of a specific locus in a subject's DNA. This allows us to find out whether the locus is present on one or both chromosomes of a subject.

      To do this, control DNA and experimental DNA are labeled with different fluorescent molecules of different colors (in the picture below, the control is red and the experimental is green).

      If the experimental DNA and the control DNA are identical (i.e. the target variant is present on both chromosomes), the sample will appear orange. If the control DNA has deletions, the solution will appear red. It it has insertions, it will appear green.

    36. the M/F ratio was 2.6:1 (34 males: 13 females) (fig. S1), compared to 7.4:1 (81 males: 11 females) for the other categories of families (i.e., nonconsanguineous and consanguineous simplex) (chi-square = 5.37, df = 1, P = 0.02)

      The authors observed that the proportion of affected women from consanguineous multiplex families was double that of the HMCA as a whole, and triple that of simplex families.

      This finding suggests an increased role of inherited autosomal mutations (as opposed to de novo mutations).

    37. An increased role for inherited factors in autism families with shared ancestry was also suggested by a low rate of de novo CNVs that segregated with disease

      The low rate of de novo CNVs suggests that abnormalities in autistic patients' genomes came from mutations that were already present in the parents, rather than new mutations.

    38. what would be predicted if the prevalence of autism were doubled in these families

      Hoodfar and Teebi studied the link between inbreeding and the prevalence of different genomic abnormalities.

      IThey found that the prevalence of autosomal recessive disorders was more than doubled in consanguineous families.

    39. we reasoned that a prominent involvement of autosomal recessive genes in autism would be signaled by differences in the male-to-female (M/F) ratio of affected children in consanguineous (related) versus nonconsanguineous marriages (although recessive causes of autism may still retain some gender-specific difference in penetrance)

      Based on studies of other neurological birth defects, the authors hypothesized that differences between consanguineous and non-consanguineous families in the M/F ratio of affected children would suggest that autosomal recessive genes play a large part in incidence.

    40. Marriage between first cousins increases the prevalence of neurological birth defects by about 100%

      Because first cousins share a larger portion of their genome than two unrelated individuals, there is a higher chance that a child will inherit disease-causing mutations.

    41. The Homozygosity Mapping Collaborative for Autism (HMCA) (21) has recruited 104 families (79 simplex and 25 multiplex) from the Arabic Middle East, Turkey, and Pakistan (table S1 and fig. S1), of which 88 pedigrees (69 simplex and 19 multiplex) have cousin marriages (i.e., parental consanguinity).

      The authors selected families with one or more individuals affected by autism.

      Among those families, about half have cousin marriages, which are referred to as consanguineous pedigrees.

      A simplex family is one in which there is only one person with autism. A multiplex family has multiple people with autism.

    42. Reliability between clinician assessments was high

      In order to ensure that the results obtained from this study are reliable, the authors ensured that all of the teams were using the same clinical protocol in the same way.

    43. homozygosity mapping

      To improve the quality of results, the authors chose consanguineous families (families that share a very recent ancestor), because of their high risk of having autistic children.

      Researchers at Johns Hopkins University reasoned that families with multiple females with autism must have special genetic variants for autism that can be more easily identified than when comparing other groups.

      For more information, see the Hub at Johns Hopkins.

    44. segregation analyses

      A technique used to determine how a trait is inherited, and if it is inherited in a standard (Mendelian) way.

    45. autosomal

      Refers to the autosomes, or the 22 numbered chromosomes (which do not include the sex chromosomes).

    46. pedigrees

      Refers to both the family tree and the ancestry of the subjects. In biology, pedigrees are represented with a standard set of symbols, such as those below:

    47. The accumulating number of distinct, individually rare genetic causes in autism (5, 10, 11) suggests that the genetic architecture of autism resembles that of mental retardation and epilepsy, with many syndromes, each individually rare, as well as other cases potentially reflecting complex interactions between inherited changes (12).

      Studies have shown that there are many unique combinations of mutations that can cause autism, as is the case with intellectual disability and epilepsy.

      Unfortunately, given that there are so many ways for autism to occur, it is difficult to identify all of the mutations and changes that can lead to symptoms.

    48. syndromic autism

      Here, "syndromic" means common varieties of autism.

    49. copy number variants

      Phenomenon in which sections of the genome are repeated, deleted, or inverted. It has been shown that CNVs at specific locations increase the risk to develop autism.

    50. chromosomal anomalies have been reported in 1 to 2% of cases of autism

      Data supports the fact that autism is linked with several genomic regions. Nnew regions are still being identified today.

    51. Autism includes mental retardation in up to 70%

      Autism is associated with intellectual disability (formerly called mental retardation*) about 70% of the time, and males are more often diagnosed.

      There is no evidence that social class has an impact on the incidence of the disease, but there is not enough data to know if race or ethnicity influence the incidence of autism.

      There is also no available data to support the idea that incidence of autism is changing over time.

      *For more on the movement to change the language of disability, see the Wall Street Journal.

    52. de novo

      In this article, the authors focus on patients who inherited long deletions or additions from their parents.

      However, this is not the only approach to understanding the genetics of autism. Some look directly at the appearance of de novo single nucleotide polymorphisms (mutations to a single base).

    53. de novo mutation

      A mutation is de novo when it appears for the first time in an individual, rather than being inherited.

      It is usually the result of a mutation in the germ line (the cells that produce sperm and eggs) of one of the parents, or a mutation that arises in the fertilized egg itself.

      It is also known as a new mutation.

    54. highly heritable, they exhibit wide clinical variability and heterogeneous genetic architecture, which have hindered gene identification

      Several research teams have worked independently to identify loci that could be responsible for autism. However, this has been difficult due to the high number of genes that could be involved and the high variability between affected individuals.

    55. neuropsychiatric

      A mental health disorder that is caused by the nervous system.

    56. heterogeneous disorders

      Disorders like autism that can result from many different genetic anomalies.

      Autism is difficult to characterize not only because there are many different genetic causes, but also because autism sometimes results when several otherwise benign mutations come together in the genome of an individual.

    57. homozygosity mapping

      A method for mapping genes involved in rare, recessive disorders. It is used in inbred populations (populations where many individuals are related to each other). Because these populations are very highly related, individuals will share large areas of their chromosomes in areas surrounding target genes.

    58. level of expression changes in response to neuronal activity

      Synapses (the electric signals that transfer information in the nervous system) regulate the expression of some genes.

      Among the genes regulated by neuronal activity are those that are involved in learning.

    59. mapped several loci

      Locus (pl. Loci.) : The locus of a gene is its physical location on a specific chromosome.

      "Mapping" a locus means finding out where it is physically located on a chromosome.

      Example: location of the genes BRCA 1 and BRCA 2:

      Example: location of the genes *BRCA *1 and *BRCA *2

    60. autism-spectrum disorders

      Autism-spectrum disorders (ASD), sometimes referred to collectively as "autism," are a family of developmental disorders that have different symptoms and intensities.

    1. A. berteroi is effectively pollinated by two native solitary bees

      The authors found that A. berteroi is best pollinated by bees.

      This is drawn from the fact that other visitors did not carry or deposit pollen well.

    2. Our results contrast with the findings of Moré et al. (2007) and de Araújo et al. (2014), who reported that flowers of Mandevilla spp. were pollinated exclusively by pollinators with long, thin proboscides. Additionally, de Araújo et al. (2014) reported that Agraulis vanillae and Ascia monuste are the effective pollinators of Mandevilla tenuifolia; coincidently, these two taxa were the same non-skipper butterfly visitors of A. berteroi in southern Florida.

      Results were different from previous research who showed that one species were pollinated by long, thin mouth parts.

    3. The principal pollinators of A. berteroi in the pine rocklands of south Florida are two native bees; bee pollination (mostly by Euglossine bees) has been previously reported for this family (Lopes and Machado 1999; de Moura et al. 2011).

      The author is explaining that the pollination of the species "Euglossine" has been experimented on before. With this being said, the previous work tested these bees and how they interact with plants.

      In the above article, the author is specifically experimenting on this family of bees and how they interact with A. berteroi in the pine rockland environment. The author is more concerned with how these bees interact with this specific plant.

    4. Table 4. Proboscis measurements (mean and standard error) for flower visitors to A. berteroi. Proboscis width and length with the same letters are not significantly different with Tukey comparisons.

      In this table, the author describes how the width and length of the insects proboscis play a role in pollination.

      This chart was made to determine the differences in proboscis.

    5. The complex flower morphology of A. berteroi is similar to the morphology described for other Apocynaceae (Barrios and Koptur 2011). The flowers restrict access to only those visitors with mouthparts long enough to reach the nectar at the base of the floral tube. Furthermore, the sugar concentration of the nectar (30–67 %) is within the range of values reported for flowers pollinated by long-tongued bees (∼40 %; Proctor et al. 1996). Although Pascarella et al. (2001) stated that A. berteroi is visited exclusively by Lepidoptera, our field observations showed that long-tongued bees were common floral visitors, as well as skippers. Skippers were the most frequent and constant visitors, often visiting numerous flowers of the same species in a row.

      Apocynaceae flowers restrict visitors with mouthparts long enough to reach the base of the floral tube.

      Previous data states that the A. berteroi species is only visited by skipper butterflies. However, the authors found they are also visited by long-tongued bees to the same extent.

    6. appears that they were acting as nectar thieves.

      These butterflies were taking the reward meant for true pollinators without actually aiding the plant in reproduction.

    7. the width of the proboscis of the pollinators of A. berteroi is more important than the length in determining pollen transfer efficiency.

      This study found a correlation between the thickness and effectiveness of feeding parts used by pollinators.

      It is possible that a wide pollen receptacle results in a need to have thicker feeding parts.

    8. The final test of pollinator effectiveness, whether flowers visited by the different pollinators set fruit, provided clear results. Placing potted plants in the field, observing visits, bagging, tagging and following subsequent fruit set showed that only flowers visited by long-tongued bees set fruit following a single visit. Of the 44 flowers visited by long-tongued bees, 16 (36.4 %) set fruit. None of the flowers visited by the other pollinator groups (4 by non-skippers butterflies, 19 by skippers and 2 by short-tongued bees) produced any fruit. Fruit set differed significantly among pollinator groups (Kruskal–Wallis test, χ23=111.7, P = 0.009, n = 69). Though the sample sizes were small for non-skipper butterflies and short-tongued bees due to their lower rate of visitation (Table 2), we also found that these groups of visitors do not carry significant amounts of pollen on their proboscides; consequently, we conclude that these two groups of visitors are much less effective pollinators of A. berteroi than are long-tongued bees.

      The authors found that only flowers visited by long-tongued bees produced fruit after a single visit.

      The authors also determined that non-skipper butterflies and short-tongued bees are less effective pollinators in comparison.

    9. We then used monofilament nylon fishing line of four different diameters (4 lb, 0.20 mm diameter; 6 lb, 0.23 mm diameter; 8 lb, 0.28 mm diameter and 25 lb, 0.53 mm diameter) inserted into single flowers to simulate flower visits.

      Fishing line was used to simulate repeatedly the collecting of nectar. This could then be used to see which line (stand-in for proboscis) collected the most pollen, and if it correlated with thickness.

    10. Table 1. Flower visitors of A. berteroi observed in the study sites, and presence/absence of pollen on the proboscis.

      In this table, the author describes various interactions the visitor encountered with plants.

    11. Mann–Whitney test (post hoc)

      Non-parametric (not assuming a normal distribution) statistical test that is used to compare two sample means that come from the same population, and used to test whether two sample means are equal or not. The authors conducted the Mann-Whitney test post hoc (after the Kruskal-Wallis test) in order to compare the groups (to investigate which groups significantly differ) but with corrections to control for inflation of type I error (false positive – determining differences in the dataset when there actually is none).

    12. We chose the sites based on the presence of many individuals of the study species

      This study site was a part of a previous experiment. In the previous experiment, the study site was chosen due to the abundance of individuals that were present. Essentially, the area with a higher abundance of individuals is beneficial to the experiment. It is beneficial to use previous work as a reference, especially if there is a common factor.

    13. Angadenia berteroi bears large, showy, yellow, tubular flowers. They have the typical complex floral arrangement

      This species that will be studied shows complex floral arrangements.

    14. non-asclepiad

      A plant that is not formally a part of the family Asclepiadaceae.

    15. diversity and abundance

      Diversity describes the number of species, while abundance describes how many individuals of each species.

    16. The unusual flowers of the Apocynaceae vary in floral mechanisms (Endress and Bruyns 2000), and insects are the major floral visitors of Apocynaceae s.l.

      The following conducted on Angadenia berteroi, a flower from the Apocynaceae family native to south Florida describe the pollination patterns of butterflies and bees.


    17. tubular flowers

      A type of flower that has a long, thin, tube-like structure. The tube-like structure is formed by the pedals and often separate the mouth into a flared shape.

    18. In hawkmoth-pollinated plants, floral tube length determines which species may transfer pollen; hawkmoths with tongues that are too short or too long will not pick up pollen effectively

      Floral tube length in hawkmoth-pollinated plants will determine which insect will transfer pollen. if it is too short or too long they will not be effective.

    19. Several studies have reported that the body structure of floral visitors, especially the feeding apparatus associated with the dimensions and the morphology of the flowers, is one of the factors determining which visitors can effectively function as pollinators

      The structure of the insect determines the effectiveness of the pollination as well as the shape of the flower like the length of mouth part and floral tube.

    20. the majority of plant species are visited by a variety of pollinator groups, but visitation does not necessarily imply pollination; not all flower visitors are important and effective pollinators (Stebbins 1970; Waser et al. 1996; Fenster et al. 2004; Ne'eman et al. 2010).

      Most plants show visitation from other insects but not all pollinate.

    1. The natural geographic range of the genus in the New World is from northern Mexico to northern Argentina.

      A new Piper species called Piper kelleyj was found in Equador by University of Cincinnati botanist Eric Tepe. The plant is now commonly known as "pink belly" pepper. This is because of the rosy underside of its leaves. It hosts 40 different species of insects (at least).


    2. Finally, we assessed the degree to which Piperphylogenetic relationships are related to differences in secondary chemical composition and community assembly.


      The research by Martinez and his colleagues used fossil from Piper and compared them to angiosperm species (a plant that has flowers and produces seeds) in order to evaluate the age divergence of the taxa. The divergence was estimated at thirty millions years.

    3. Most of the chemicals found by our analysis are well known to confer direct and indirect anti-herbivore protection to plants

      The Piper species that were sampled were found to contain secondary chemicals that likely function to protect the plant from herbivores.

    4. phylogeny

      Evolutionary history that traces the relationship between organisms.

    5. allelopathy

      A mechanism plants use to ensure their survival.

      The plant produces one or more biochemicals that affect neighboring competitors in their growth and/or reproduction.

    6. Our results suggest that Piper species that are chemically dissimilar from those already present in a patch would be more likely to colonize and persist within the patch.

      Species with different chemical properties are less likely to compete with one another, therefore tend to coexist with each other.

    7. Nonetheless, phylogenetic underdispersion was significant for both -NRI and -NTI, a result that supports the idea that the effect of phylogeny on community assembly is associated with strongly conserved traits not measured in this study.

      Species that are closely related tend to coevolve, which allows them to coexist together more easily than non-related species.

    8. Sedio et al. 2013

      Sedio describes the phylogenetic niche conservatism (PNC) phenomenon that occurs in plants.

      In this phenomenon, a plant's microhabitat patterns are influenced by the biogeographical history of the plant's ancestors. He explains how related taxa are able to coexist since they were able to retain significant niche characteristics of their common ancestors.

    9. Kursar et al. (2009)

      The young leaves make large energy investments in chemical, developmental defenses, and floral nectar.

      There were many variations among species suggesting that herbivory is a strong selective agent.

    10. Cavender-Bares et al. 2004

      The research performed by Cavender-Bares and his colleagues highlights the importance of evolutionary processes combined with community interactions in community dynamics.

      The combination of phylogeny with their functional attributes help in better understanding communities.

    11. MacArthur and Levins 1967

      MacArthur and Levins explain that diversity of species living within the same environment can be explained as a result of limiting similarity.

    12. (Götzenberger et al. 2012)

      Götzenberger's research suggest that species distribution is largely influenced by intraspecific competition (competition within the same species)

      As the number of superior competitors increases, diversity decreases. This holds true only until other species are excluded.

    13. abiotic environment

      Non-living physical and chemical components that affect living organisms and the surrounding ecosystem.

    14. Hartmann 2007

      Hartman's research focused on secondary metabolism in plants. These were associated with genes that have a high ability to change and adapt to the pressures of their environment.

      Each plant population has unique secondary chemicals that have adapted to a plant's specific niche.

    15. Swenson 2013

      Swenson summarizes how to estimate the similarity between species by using both functional traits and phylogenetic trees.

      He uses the data from these approaches to test the mechanistic community hypothesis.

    1. we tested six sgRNAs targeting enhanced green fluorescent protein (EGFP)

      The authors used sgRNAs to target enhanced green fluorescent protein (EGFP) cells.

      The EGFP cells allow the cell to express fluorescent color. sgRNAs target these cells and destroy them. In cells where the sgRNA removed the EGFP gene, there is no fluorescent color.

    1. Contrasting taxonomic and functional responses of a tropical tree community to selective logging

      In logged habitats, does diversity of species, or their function in the ecosystem matter more?

  2. Mar 2018
    1. crypt regions of the organ

      See Dr. Bethany Radar and Dr. Ned Ruby use confocal images and immunocytochemistry to look at Vibrio fischeri in the crypts of the light organ:

      A look at Vibrio fischeri

    1. 46. Bhatt US et al. 2010 Circumpolar Arctic tundra vegetation change is linked to sea ice decline. Earth Interact. 14, 1 – 20. (doi:10.1175/ 2010EI315.1)

      Sea ice decline due to global warming is affecting plant productivity in arctic regions.

    2. 16. Chapin III FS, Shaver GR. 1985 Arctic. In Physiological ecology of North American plant communities (eds BF Chabot, HA Mooney), pp. 16– 40. New York, NY: Chapman and Hall.

      This paper explains the effects of low temperatures on the development of arctic plants.

    3. 15. Lambert AM, Miller-Rushing AJ, Inouye DW. 2010 Changes in snowmelt date and summer precipitation affect the flowering phenology of Erythronium grandiflorum (glacier lily; Liliaceae). Am. J. Bot. 97, 1431– 1437. (doi:10.3732/ajb. 1000095)

      This paper talks about the implications that alterations in the phenology of E. grandiflorum might have on its surrounding environment specially pollinators and herbivores.

    4. 11. Arft AM et al. 1999 Responses of tundra plants to experimental warming: meta-analysis of the International Tundra Experiment. Ecol. Monogr. 69, 491– 511.

      This source compiled the data from 13 ITEX sites and analyzed how the phenology, growth, and reproduction of plants in Tundra regions was affected by warming climate.

    5. 8. Xu L et al. In press. Temperature and vegetation seasonality diminishment over northern lands. Nat. Clim. Change. (doi:10.1038/nclimate1836)

      This paper adds on by going more in depth on how an increase in temperature near the poles is affecting the photosynthetic activity in the plants living in these regions.

    6. 3. Cleland EE, Chuine I, Menzel A, Mooney HA, Schwartz MD. 2007 Shifting plant phenology in response to global change. Trends Ecol. Evol. 22, 357– 365. (doi:10.1016/j.tree.2007.04.003)

      Changes in plant phrenology prove that plants are being influenced by environmental changes.

    7. 1. Maxwell B. 1992 Arctic climate: potential for change under global warming. In Arctic ecosystems in a changing climate: an ecophysiological perspective (eds FS Chapin, RL Jefferies, JF Reynolds, GR Shaver, J Svoboda), pp. 11–34. San Diego, CA: Academic Press.

      Maxwell builds on this data by presenting the different models used to study the effect of climate change in the Arctic ecosystems.

    8. [46]

      Sea ice decline due to global warming is affecting plant productivity in arctic regions.

    9. [12]

      Heat sums have increased over time for flowering and senescence. Warming induced early leaf bud bursts, growth, and reproduction but did not affect senescence. Study was performed in multiple sites in the arctic region over a course of four years.

    10. [11].

      Warming induced early leaf bud bursts, growth, and reproduction but did not affect senescence. Study was performed in multiple sites in the arctic region over a course of four years.

    11. Significance

      Climate change will result in a shifting of where plants are usually located on the planet. Southern plants will move into higher latitudes, for example.

    12. p = 0.013

      P values greater than 0.001 are generally considered insignificant in statistics.

    13. (H2) Flower and leaf bud break of high Arctic plants should be more sensitive to temperature increases than those of low Arctic and alpine plants.

      The trends found indicated that high-elevation Arctic plants grew, flowered and aged at lower heat thresholds than low-elevation Arctic and alpine plants.

    14. Flower and leaf bud break are occurring earlier as sites become warmer.

      There was a strong negative relationship between the temporal trend of phenological events and the summer temperature trend for each species and site.

    15. temporal trends of heat sums (βTDD_x_YEAR) showed significantly increased heat sums over time for greening but a tendency for lower heat sums over time for flowering and senescence.

      The accumulated daily temperature required for plant growth has increased over time.

      The accumulated daily temperature required for flowering and aging has decreased over time.

    16. Trends in the timing of events as represented by βDOY_x_YEAR showed significantly later greening (positive slope) but tendencies for earlier flowering and earlier senescence (negative slopes) over the study.

      With warmer temperatures, plants are growing at a later time in the year but flowering and aging at an earlier time in the year.

    17. case-resampling bootstrap approach

      "Bootstrapping" is a process that allows scientists to ensure that their statistical data sets are correct by doing hundreds of random samplings.

    18. To determine whether observed trends in the timing of phenological events were associated with summer temperature trends, we tested the relationship between (βDOY_x_YEAR) with the summer temperature trend (βDOY_x_TAIRSUMMER) for each species at each subsite using linear mixed models, with site, subsite (nested within site) and species as random factors in JMP.

      Statistical analysis such as linear mixed models were used to demonstrate if the trends in the timing of phenological events were associated with the temperature during the summer.

    19. The slope of this relationship (β in days °C−1) has been termed the temperature sensitivity by other authors

      Large species sampling size necessary (or interspecific variation in species may be too high)

      Warming experiments underpredict the advance of spring events

      Experimental results alone cannot be used for parameterizing species distribution and ecosystem models

      Best (currently) measure: observational data

    20. Because site effects such as latitude, elevation and species traits have strong influences on the calendar date that a phenological event occurs, we did not use the DOY associated with a phenological event as a direct measure of phenological response. Instead, we used two types of measures that are largely independent of the site-specific properties (table 2). First, we calculated the TDD from snowmelt until the occurrence of the phenological event for each species-plot combination. This measure reflects the amount of heat accumulated from snowmelt until the phenological event was observed. Second, for each species-subsite combination, we calculated the slopes (β) of the relationships between the timing of the phenological event (represented as DOY or TDD) and the calendar year or site temperature (measured as air temperature of the spring or summer).

      Two types of measures were used to calculate the time of phenological events. One of them was thaw degree days (TDD) which was able to show how much heat was produced from snowmelt until the phenological response occurred. The other measure was done by comparing the slopes of each species-subsite. The slopes represented the time of the phenological event and the year or temperature it took place. One of the advantages of this measure is that it shows the comparison between species and sites.

    21. To evaluate potential differences in species responses among locations, sites were categorized into climatic zones as in previous syntheses [11,22,23]: high Arctic, low Arctic or alpine. Subsites were categorized as dry, moist or wet, where dry refers to plant communities on well-drained, mineral soils typically located on ridges, moist refers to sites with some soil drainage, and wet refers to plant communities with water tables frequently near or above the surface.

      The different locations used was categorized based on climate zones which were high Arctic, low Arctic, and alpine. They were also categorized as dry, moist, or wet.

    22. Consequently, we used mean temperatures of month combinations (spring = April–May and summer = June–August temperatures) as the basis of the temperature analysis.

      The average temperature for spring and summer times within a year were used to analyze temperature change throughout the experiment.

    23. Mean monthly air temperatures for the months preceding the growing season and months of the growing season (April–August) were calculated for each study site each year for comparison with plant phenology.

      The plant phenology was compared with the mean monthly air temperatures.

    24. A cubic spline interpolation

      Used to show the most accurate average of the temperatures.

    25. The weather dataset was based on data collected at the sites

      The data used for the weather was gathered from the specific site. However, in some places such as Finse, Norway, where the weather data was not available for a period of time, the averages from previous years was used.

    26. A priority-ranking lumping scheme that accounted for differences in plant morphology was used to consolidate phenological variables, although for a given species at a subsite, the phenological definitions were consistent over time.

      The plants were ranked based on the way they looked.

    27. Flowering and leafing stages were compiled from most sites at an observation resolution of one to two times per week.

      The plants' flowers and leafs were measured once or twice a week.

    28. insulator

      Material or substance that prevents the loss of heat to the environment.

    29. Our approach was to use long-term trends and interannual variability across the ITEX control plots to evaluate change in plant phenology in relation to temperature.

      Plant phenology changes were measured using trends and interannual variations.

    30. photoperiod

      The period of time every day that the plant receives light.

    31. anthesis

      The period at which the plant grows and opens its flowers.

    32. threshold

      The specific temperature that needs to be reached in order for a result to occur.

    33. Senescence

      The process of aging.

    34. bud

      A type of structure that develops on the stem of the plant which later grows into another part of the plant like a flower.

    35. evergreen

      Retaining green leaves throughout the year.

    36. forb

      Herbaceous plant without grass-like features in contrast to graminoids.

    37. synthesis

      A collection and combination of data.

    38. Ground-based phenological observations of individual plant species and growth forms have the potential to improve our understanding of the mechanisms behind the vegetation response to climate warming.

      Climate change brings about higher temperature which means more snow will melt in the arctic tundras. This might impact the growth of new plants in this environment.

      Read more in Livescience https://www.livescience.com/28406-arctic-tundra-turning-green.html

      Watch a video from National Geographic. https://voices.nationalgeographic.org/2016/11/17/climate-and-the-dividing-line-between-forest-and-tundra/

    39. heterogeneous

      Being different in structure or composition.

    40. deciduous

      Characteristic of shedding leaves.

    41. green-up

      The start of the growth cycle of a plant.

    42. Plant phenological responses to these increases in season length and temperature are uncertain, but understanding changes as they occur is essential for predicting future changes in tundra vegetation processes

      Constantly observing and following the seasonal changes that occur with these plants is very important in understanding the future of the plants and their habitat.

    43. heat sum thresholds

      The accumulated daily temperature required for plants to flower or start growing or produce fruits.

    44. moisture gradients

      The difference in moisture ( Liquid such as water present as vapor) between the inside and outside of a material like wood or soil.

    45. Tundra

      Region characterized by low temperatures, freezing soil and treeless terrain composed mainly of cold-resistant plants.

    46. trace gas

      Gas that is present in very small concentrations in the Earth's atmosphere.

    47. phenology

      Key seasonal changes in plants like the timing of flowering, especially in relation to climate.

    48. alpine

      Relating to high-elevation mountains.

    1. 38. Ollerton J, Killick A, Lamborn E, Watts S, Whiston M. 2007. Multiple meanings and modes: on the many ways to be a generalist flower. Taxon 56:717–728. doi:10.2307/25065856

      The meaning of a generalist flower can mean different things to different people. This review aims to assess these different meanings in the context of the ecological processes such as pollination.

    2. 36. Ne'eman G, Jürgens A, Newstrom-Lloyd L, Potts SG, Dafni A. 2010. A framework for comparing pollinator performance: effectiveness and efficiency. Biological Reviews 85:435–451.

      Measuring pollinator performance is significant to conservation efforts. However, comparing pollinator performance among pollinator groups is difficult due to the differences in collection methods and the diversity of the pollinators. This review resolves vague concepts.

    3. 34. Moré M, Sérsic AN, Cocucci AA. 2007. Restriction of pollinator assemblage through flower length and width in three long-tongued hawkmoth–pollinated species of Mandevilla (Apocynaceae, Apocynoideae). Annals of the Missouri Botanical Garden 94:485–504. doi:10.3417/0026-6493(2007)94[485:ROPATF]2.0.CO;2

      The author studied the way the species of insects obtain the flowers nectar. Specifically, the flowers that have a greater length to their nectar. This research was to determine how specific insects can obtain nectar and what specific plants they have to go to gain what they are looking for.

    4. 27. Inouye DW. 1980. The effect of proboscis and corolla tube lengths on patterns and rates of flower visitation by bumblebees. Oecologia 45:197–201. doi:10.1007/BF00346460

      The Authore studied how length of mouth parts and tubes will affect the vistiation from bumble bees

    5. 22. Galetto L. 1997. Flower structure and nectar chemical composition in three Argentine Apocynaceae. Flora192:197–207.

      The author researched the floral structure and what components are in their nectar in three different "Apocynaceae" species. Reviewing these components can verify the similarities each plant may have with each other.

    6. 10. Campbell DR, Waser NM, Price MV. 1996. Mechanisms of hummingbird-mediated selection for flower width in Ipomopsis aggregata. Ecology 77:1463–1472. doi:10.2307/2265543

      The author studied how hummingbirds pollinate flowers

    7. 7. Barrios B, Koptur S. 2011. Floral biology and breeding system of Angadenia berteroi (Apocynaceae): why do flowers of the pineland golden trumpet produce few fruits? International Journal of Plant Sciences172:378–385. doi:10.1086/658153

      The author studied the biology of flower plant "Angadenia berteroi" and how they breed.

    8. 4. Arbulo N, Santos E, Salvarrey S, Invernizzi C. 2011. Proboscis length and resource utilization in two Uruguayan bumblebees: Bombus atratus Franklin and Bombus bellicosus Smith (Hymenoptera: Apidae). Neotropical Entomology 40:72–77. doi:10.1590/S1519-566X2011000100010 

      Arbulo et. al. studies the proboscis length of two Uruguayan bumblebees in relation to the depth of the floral tube. The study found both species of bumblebees used the cultivated species of flowers. However, they did so in different amounts.

    9. 2. Alexandersson R, Johnson SD. 2002. Pollinator–mediated selection on flower–tube length in a hawkmoth–pollinated Gladiolus (Iridaceae). Proceedings of the Royal Society B: Biological Sciences 269:631–636. doi:10.1098/rspb.2001.1928 

      How tube length will determine the type of pollination

    10. 1. Adrienne B, Venables B, Barrows EM. 1985. Skippers: pollinators or nectar thieves? Journal of the Lepidopterist's Society 39:299–312.

      The author researched other articles based on pollinators and nectary reward

    11. with many reports of butterflies and hawkmoths pollinating species of this family (Haber 1984; Darrault and Schlindwein 2005; Sugiura and Yamazaki 2005; Moré et al. 2007).

      Haber found that hawkmoths are frequent pollinators of these families, but require a significant nectar reward to do so.

      Darrault and Schlindwein found these butterflies and moths do pollinate. Furthermore, in contrast to this study, they found that diameter of the mouth parts showed no correlation with pollen collected.

    12. Many studies of other plant–pollinator systems provide evidence that the morphological match between the pollination apparatus and the length of the proboscis is associated with pollination effectiveness (Inouye 1980; Waser et al. 1996; Castellanos et al. 2004; Moré et al. 2012; Miller et al. 2014).

      Inouye found that proboscis length was correlated with a bee's time spent at a flower. Waser found that many pollination systems tend towards specialization.

      This implies that flowers adapt their shape and length to accomodate one group of pollinators. Length is a great determinant in these cases.

    13. In many self-incompatible Apocynaceae, flower revisitation increases the probability that self-pollen is deposited onto the stigma, leading to ovule and fruit abortion (Lipow and Wyatt 1999, 2000; Wyatt et al. 2000; Wyatt and Lipow 2007).

      Lipow and Wyatt found in multiple studies that self pollination in this family of plants prevents fruit bearing. This can be problematic, as it can decrease seed output. As such, it could create pressure for plants to evolve to punish revisitors.

    14. South Florida


      Given that bees are being shown to be very important pollinators, it is relevant that South Florida is currently undergoing efforts to preserve bee populations.

    15. Pollination success was quantified for these same flowers by recording the fruit production of visited flowers on the potted plants, maintained in the greenhouse. We placed at least 15 plants per day, each with one to three open flowers, over 20 days of observations, using a new set of plants each day. We recorded a total of 69 visits to over 400 flowers observed in this potted plant placement experiment. Pollination efficiency of each visitor group was assessed by comparing the percentage of visited flowers that produced fruit after a single visit.

      The success rate of the pollination was determined by recording the fruit produced by visited flowers. 15 potted plants having 1-3 open flowers were studied over 20 days, and a new set of plants was used every day. 69 total visits to over 400 flowers were observed throughout the course of the experiment.

    16. To determine the most effective pollinator, we placed 15 greenhouse-grown potted plants in the field to quantify pollination success at Site 3, the site with the highest visitation frequency (B. B. Roque, personal observations). On 20 different days during the flowering period, we compared the qualitative effectiveness of the different pollinator groups by allowing a single visit to individual flowers on the potted plants. Flowers that were ready to open prior to observation periods were bagged, while in bud, to exclude visitors. At the time of observation (from 9:00 am to 12:00 pm), bags were removed and flowers exposed to foraging insects. For a specific flower, pollinator visits were restricted to a single visit by one individual from one of the four groups of pollinators. After visitation, a flower was labelled (by pollinator group) and bagged to exclude subsequent visitors.

      For this experiment, the authors wanted to determine which was the best pollinator in relation to effectiveness. They grew 15 plants in the greenhouse and then placed them at the site with the highest number of visitors. Over 20 days, a single visit by pollinators was allowed for each individual flower. Bags were placed on the flowers whenever they were not being studied so as to avoid pollinator visits.

    17. To examine a possible relationship between line thickness and pollen deposition, we hand pollinated fresh flowers using fishing line of four different diameters. Each thickness was inserted into a fresh flower to the bottom of the corolla tube to collect pollen (as above); we then stained entire length of the fishing line with methylene blue to stain the adhering pollen grains and introduced the stained portion into another new fresh flower.

      In this experiment, fresh flowers were pollinated using four fishing lines of different diameters to simulate different proboscis diameters. The fishing lines were inserted into the floral tube in order to collect pollen. Then, the length of the fishing lines were stained blue. The fishing lines were re-inserted and the pollen that attached were stained blue. The same fishing lines were then inserted into other fresh flowers.

    18. To quantify the efficiency of each visitor group, we estimated pollen on the visitor mouthparts as the average number of pollen grains per individual visitor of each group.

      The authors counted average number of pollen grains per group, as well as time spent at each flower, and the behavior of the pollinator after leaving the flower.

      All of these metrics are important to pollination efficiency.

    19. We haphazardly selected plants with open flowers for each of the intervals.

      The authors use the word 'haphazardly' to indicate randomness in the sampling of the flowers. It is important to have randomness to avoid bias.

    20. The flowers have no notable fragrance, and offer viscous nectar as a pollinator reward, with the sugar concentration of the nectar ranging from 30 to 67 %

      This species has no fragrance and uses nectar as a reward with 30-67% sugar concentration as the reward.

    21. stigma

      This part of the flower collects the pollen that has been delivered, whether by wind or pollinators.

    22. foraging

      The process in which resources are searched for and gathered.

    23. Angadenia berteroi 

      A flower species that is known as the Pineland Golden Trumpet. This plant is native to Pine Rocklands.

    24. pollinia

      A mass of pollen grains. These pollen grains are the product of each anther lobe of some flowers (especially orchids). Single or paired pollinia are attached to, and carried by pollinating insects.

    25. Proboscis

      In many insects, the proboscis is the elongated sucking mouthpart that is typically tubular and flexible. Pollinators use this to suck the nectar of flowers.

    26. conspecific

      Refers to another organism of the same species.

    27. perianth

      The outer part of the flower, which consists of sepals and pedals.

    1. species chemical dendrogram

      An informal phylogenetic tree that represents clusters of species with similar characteristics.

    2. induction

      Secondary compounds that are only present after a stimulus occurs.

      For instance, one stimulus could be leaf damage caused by herbivory.

    3. gas chromatography mass spectroscopy (GC-MS)

      Gas Chromatography: Used to separate and analyze compounds that do not decompose. Measures the content of multiple components in a sample.

      Mass Spectroscopy: Measures the characteristics of individual molecules. This is done by converting the molecules into ions so they can be manipulated by magnetic and electrical fields.

      GC-MS is a machine that does both.

    4. community assembly

      The factors that dictate the presence and amount of a species within a community.

    5. sympatric

      Species or populations that reside in the same geographic area.

    6. ecologically divergent

      Differences with species resulting from reproductive barriers.

    7. “species-limiting similarity”

      The most amount two species can share their living environments and still coexist.

    8. trophic level

      Level in the food chain an organism belongs to in an ecosystem. For instance, plants that are primary producers belong to the first trophic level.

    9. congeneric taxa

      Of related nature or origin. Of the same genus.

    10. communities

      A collection of plants or organisms in a specific geographical area that exist at a specific time.

    11. secondary chemical composition

      Compounds that play a role in a plant's ecological interaction with its environment.

      For example, secondary compounds may function in protection against herbivores and/or pollinator attractants

    1. Solitary invasive orchid bee outperforms co-occurring native bees to promote fruit set of an invasive Solanum

      Does There Need To Be an "I" in Team? Loner bee excels in promoting fruit set on Invasive plant species Solanum when compared to socially outgoing native bees

    1. Why can’t we tickle ourselves (2)

      This article discusses how researchers are exploring why humans can't tickle themselves.

      Read more about self-tickling in Discover: http://discovermagazine.com/2014/sept/2-tickle-yourself-elmo

    2. ultrasonic vocalizations

      Noises rats make that are outside the range of human hearing.

  3. Feb 2018
    1. This suggests that the follower-aggregate dynamics are driven by self-organization


      Explain how the results support this conclusion

    2. closure


    3. snowballing


    4. The specific criterion for inclusion in the list was that the group explicitly expressed its support for ISIS, publishing ISIS-related news or propaganda and/or calling for jihad in the name of ISIS

      Author's experiments

      why did they choose these criteria? why are they important?

    5. Chechen origin focused in the Caucasus region near ISIS’s main area of influence in the Levant

      Author's experiments

      Please give background on why this is important

    6. We chose VKontakte for our pro-ISIS analysis because

      Author's experiments

    7. language-agnostic


    8. how support for an entity like ISIS develops online

      Author's experiments

      Question they're asking

    9. Recent research has used records of attacks to help elucidate group structure in past organizations for which the Internet was not a key component (3, 6, 12), the nature of attacks by lone-wolf actors (13), and the relationship between general online buzz and real-world events (14–16)

      Previous work

    10. ad hoc


    11. extremist


    1. DEET repellency

      DEET is a ubiquitous repellent known to effectively provide protection from many biting insects, particularly mosquitoes. Its exact interaction between itself and the organisms it targets are not yet fully known. Yet, what is understood is that it possesses two primary lines of negative feedback that act as a defense to prevent feeding. These two are the olfactory and gustatory levels. This, along with other smaller contributors are what give DEET its ability to deter insects