The tuatara genome reveals ancient features of amniote evolution.

The tuatara (Sphenodon punctatus)-the only living member of the reptilian order Rhynchocephalia (Sphenodontia), once widespread across Gondwana1,2-is an iconic species that is endemic to New Zealand2,3. A key link to the now-extinct stem reptiles (from which dinosaurs, modern reptiles, birds and mammals evolved), the tuatara provides key insights into the ancestral amniotes2,4. Here we analyse the genome of the tuatara, which-at approximately 5 Gb-is among the largest of the vertebrate genomes yet assembled. Our analyses of this genome, along with comparisons with other vertebrate genomes, reinforce the uniqueness of the tuatara. Phylogenetic analyses indicate that the tuatara lineage diverged from that of snakes and lizards around 250 million years ago. This lineage also shows moderate rates of molecular evolution, with instances of punctuated evolution. Our genome sequence analysis identifies expansions of proteins, non-protein-coding RNA families and repeat elements, the latter of which show an amalgam of reptilian and mammalian features. The sequencing of the tuatara genome provides a valuable resource for deep comparative analyses of tetrapods, as well as for tuatara biology and conservation. Our study also provides important insights into both the technical challenges and the cultural obligations that are associated with genome sequencing.

Publisher Correction: The tuatara genome reveals ancient features of amniote evolution.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Flexibility of the petunia strigolactone receptor DAD2 promotes its interaction with signaling partners.

Strigolactones (SLs) are terpenoid-derived plant hormones that regulate various developmental processes, particularly shoot branching, root development, and leaf senescence. The SL receptor has an unusual mode of action. Upon binding SL, it hydrolyzes the hormone, and then covalently binds one of the hydrolytic products. These initial events enable the SL receptor DAD2 (in petunia) to interact with the F-box protein PhMAX2A of the Skp-Cullin-F-box (SCF) complex and/or a repressor of SL signaling, PhD53A. However, it remains unclear how binding and hydrolysis structurally alters the SL receptor to enable its engagement with signaling partners. Here, we used mutagenesis to alter DAD2 and affect SL hydrolysis or DAD2's ability to interact with its signaling partners. We identified three DAD2 variants whose hydrolytic activity had been separated from the receptor's interactions with PhMAX2A or PhD53A. Two variants, DAD2N242I and DAD2F135A, having substitutions in the core α/ß hydrolase-fold domain and the hairpin, exhibited hormone-independent interactions with PhMAX2A and PhD53A, respectively. Conversely, the DAD2D166A variant could not interact with PhMAX2A in the presence of SL, but its interaction with PhD53A remained unaffected. Structural analyses of DAD2N242I and DAD2D166A revealed only small differences compared with the structure of the WT receptor. Results of molecular dynamics simulations of the DAD2N242I structure suggested that increased flexibility is a likely cause for its SL-independent interaction with PhMAX2A. Our results suggest that PhMAX2A and PhD53A have distinct binding sites on the SL receptor and that its flexibility is a major determinant of its interactions with these two downstream regulators.

Determinants of Latent Tuberculosis Treatment Acceptance and Completion in Healthcare Personnel.

BACKGROUND: US public health strategy for eliminating tuberculosis (TB) prioritizes treatment of latent TB infection (LTBI). Healthcare personnel (HCP) are less willing to accept treatment than other populations. Little is known about factors associated with HCP LTBI therapy acceptance and completion. METHODS: We conducted a retrospective chart review to identify all employees with LTBI at time of hire at a large academic medical center during a 10-year period. Personal demographics, occupational factors, and clinic visit variables were correlated with LTBI treatment acceptance and completion rates using multivariate logistic regression. RESULTS: Of 470 HCP with LTBI for whom treatment was recommended, 193 (41.1%) accepted treatment, while 137 (29.1%) completed treatment. Treatment adherence was better with 4 months of rifampin than 9 months of isoniazid (95% vs 68%, P < .005). Increased age of the healthcare worker was independently associated with lower rates of treatment acceptance (odds ratio [95% confidence interval]: 0.97 [0.94-0.99] per year), as was having an occupation of clinician (0.47 [0.26-0.85]) or researcher (0.34 [0.19-0.64]). Male gender was associated with higher treatment acceptance (1.90 [1.21-2.99]). Treatment completion was associated with being from a low- (9.49 [2.06-43.73]) or medium- (8.51 [3.93-18.44]) TB-burden country. CONCLUSIONS: Geographic and occupational factors affect acceptance and completion of LTBI therapy. Short-course regimens may improve adherence. Physicians, researchers, and HCP from high-TB-burden countries have lower treatment rates than other HCP. Improving LTBI treatment in HCP will require attending to cultural and occupational differences.

Estimating the biodiversity of terrestrial invertebrates on a forested island using DNA barcodes and metabarcoding data.

Invertebrates are a major component of terrestrial ecosystems, however, estimating their biodiversity is challenging. We compiled an inventory of invertebrate biodiversity along an elevation gradient on the temperate forested island of Hauturu, New Zealand, by DNA barcoding of specimens obtained from leaf litter samples and pitfall traps. We compared the barcodes and biodiversity estimates from this data set with those from a parallel DNA metabarcoding analysis of soil from the same locations, and with pre-existing sequences in reference databases, before exploring the use of combined data sets as a basis for estimating total invertebrate biodiversity. We obtained 1,282 28S and 1,610 COI barcodes from a total of 1,947 invertebrate specimens, which were clustered into 247 (28S) and 366 (COI) OTUs, of which ≤ 10% were represented in GenBank. Coleoptera were most abundant (730 sequenced specimens), followed by Hymenoptera, Diptera, Lepidoptera, and Amphipoda. The most abundant OTU from both the 28S (153 sequences) and COI (140 sequences) data sets was an undescribed beetle from the family Salpingidae. Based on the occurrences of COI OTUs along the elevation gradient, we estimated there are ~1,000 arthropod species (excluding mites) on Hauturu, including 770 insects, of which 344 are beetles. A DNA metabarcoding analysis of soil DNA from the same sites resulted in the identification of similar numbers of OTUs in most invertebrate groups compared with the DNA barcoding, but less than 10% of the DNA barcoding COI OTUs were also detected by the metabarcoding analysis of soil DNA. A mark-recapture analysis based on the overlap between these data sets estimated the presence of approximately 6,800 arthropod species (excluding mites) on the island, including ~3,900 insects. Estimates of New Zealand-wide biodiversity for selected arthropod groups based on matching of the COI DNA barcodes with pre-existing reference sequences suggested over 13,200 insect species are present, including 4,000 Coleoptera, 2,200 Diptera, and 2,700 Hymenoptera species, and 1,000 arachnid species (excluding mites). These results confirm that metabarcoding analyses of soil DNA tends to recover different components of terrestrial invertebrate biodiversity compared to traditional invertebrate sampling, but the combined methods provide a novel basis for estimating invertebrate biodiversity.

Differential gene expression in the evolution of sex pheromone communication in New Zealand's endemic leafroller moths of the genera Ctenopseustis and Planotortrix.

BACKGROUND: Sex pheromone communication in moths has attracted the attention of evolutionary biologists due to the vast array of pheromone compounds used, addressing questions of how this diversity arose and how male reception has evolved in step with the female signal. Here we examine the role of changing gene expression in the evolution of mate recognition systems in leafroller moths, particularly focusing on genes involved in the biosynthetic pathways of sex pheromones in female pheromone glands and the peripheral reception repertoire in the antennae of males. From tissue-specific transcriptomes we mined and compared a database of genes expressed in the pheromone glands and antennae of males and females of four closely related species of leafroller moths endemic to New Zealand, Ctenopseutis herana and C. obliquana, and Planotortrix excessana and P. octo. The peculiarity of this group, compared to other Lepidoptera, is the use of (Z)-5-tetradecenyl acetate, (Z)-7-tetradecenyl acetate, and (Z)-8-tetradecenyl acetate as sex pheromone components. RESULTS: We identify orthologues of candidate genes from the pheromone biosynthesis pathway, degradation and transport, as well as genes of the periphery olfactory repertoire, including large families of binding proteins, receptors and odorant degrading enzymes. The production of distinct pheromone blends in the sibling species is associated with the differential expression of two desaturase genes, deast5 and desat7, in the pheromone glands. In male antennae, three odorant receptors, OR74, OR76a and OR30 are over-expressed, but their expression could not be clearly associated with the detection of species-specific pheromones components. In addition these species contain duplications of all three pheromone binding proteins (PBPs) that are also differentially expressed among species. CONCLUSIONS: While in females differences in the expression of desaturases may be sufficient to explain pheromone blend differences among these New Zealand leafroller species, in males differential expression of several genes, including pheromone binding proteins, may underpin differences in the response by males to changing pheromone components among the species.

Characterization of Odorant Receptors from a Non-ditrysian Moth, Eriocrania semipurpurella Sheds Light on the Origin of Sex Pheromone Receptors in Lepidoptera.

Pheromone receptors (PRs) are essential in moths to detect sex pheromones for mate finding. However, it remains unknown from which ancestral proteins these specialized receptors arose. The oldest lineages of moths, so-called non-ditrysian moths, use short-chain pheromone components, secondary alcohols, or ketones, so called Type 0 pheromones that are similar to many common plant volatiles. It is, therefore, possible that receptors for these ancestral pheromones evolved from receptors detecting plant volatiles. Hence, we identified the odorant receptors (ORs) from a non-ditrysian moth, Eriocrania semipurpurella (Eriocraniidae, Lepidoptera), and performed functional characterization of ORs using HEK293 cells. We report the first receptors that respond to Type 0 pheromone compounds; EsemOR3 displayed highest sensitivity toward (2S, 6Z)-6-nonen-2-ol, whereas EsemOR5 was most sensitive to the behavioral antagonist (Z)-6-nonen-2-one. These receptors also respond to plant volatiles of similar chemical structures, but with lower sensitivity. Phylogenetically, EsemOR3 and EsemOR5 group with a plant volatile-responding receptor from the tortricid moth Epiphyas postvittana (EposOR3), which together reside outside the previously defined lepidopteran PR clade that contains the PRs from more derived lepidopteran families. In addition, one receptor (EsemOR1) that falls at the base of the lepidopteran PR clade, responded specifically to ß-caryophyllene and not to any other additional plant or pheromone compounds. Our results suggest that PRs for Type 0 pheromones have evolved from ORs that detect structurally-related plant volatiles. They are unrelated to PRs detecting pheromones in more derived Lepidoptera, which, in turn, also independently may have evolved a novel function from ORs detecting plant volatiles.

Assembling large genomes: analysis of the stick insect (Clitarchus hookeri) genome reveals a high repeat content and sex-biased genes associated with reproduction.

BACKGROUND: Stick insects (Phasmatodea) have a high incidence of parthenogenesis and other alternative reproductive strategies, yet the genetic basis of reproduction is poorly understood. Phasmatodea includes nearly 3000 species, yet only the genome of Timema cristinae has been published to date. Clitarchus hookeri is a geographical parthenogenetic stick insect distributed across New Zealand. Sexual reproduction dominates in northern habitats but is replaced by parthenogenesis in the south. Here, we present a de novo genome assembly of a female C. hookeri and use it to detect candidate genes associated with gamete production and development in females and males. We also explore the factors underlying large genome size in stick insects. RESULTS: The C. hookeri genome assembly was 4.2 Gb, similar to the flow cytometry estimate, making it the second largest insect genome sequenced and assembled to date. Like the large genome of Locusta migratoria, the genome of C. hookeri is also highly repetitive and the predicted gene models are much longer than those from most other sequenced insect genomes, largely due to longer introns. Miniature inverted repeat transposable elements (MITEs), absent in the much smaller T. cristinae genome, is the most abundant repeat type in the C. hookeri genome assembly. Mapping RNA-Seq reads from female and male gonadal transcriptomes onto the genome assembly resulted in the identification of 39,940 gene loci, 15.8% and 37.6% of which showed female-biased and male-biased expression, respectively. The genes that were over-expressed in females were mostly associated with molecular transportation, developmental process, oocyte growth and reproductive process; whereas, the male-biased genes were enriched in rhythmic process, molecular transducer activity and synapse. Several genes involved in the juvenile hormone synthesis pathway were also identified. CONCLUSIONS: The evolution of large insect genomes such as L. migratoria and C. hookeri genomes is most likely due to the accumulation of repetitive regions and intron elongation. MITEs contributed significantly to the growth of C. hookeri genome size yet are surprisingly absent from the T. cristinae genome. Sex-biased genes identified from gonadal tissues, including genes involved in juvenile hormone synthesis, provide interesting candidates for the further study of flexible reproduction in stick insects.

Analysis of the genome of the New Zealand giant collembolan (Holacanthella duospinosa) sheds light on hexapod evolution.

BACKGROUND: The New Zealand collembolan genus Holacanthella contains the largest species of springtails (Collembola) in the world. Using Illumina technology we have sequenced and assembled a draft genome and transcriptome from Holacanthella duospinosa (Salmon). We have used this annotated assembly to investigate the genetic basis of a range of traits critical to the evolution of the Hexapoda, the phylogenetic position of H. duospinosa and potential horizontal gene transfer events. RESULTS: Our genome assembly was ~375 Mbp in size with a scaffold N50 of ~230 Kbp and sequencing coverage of ~180×. DNA elements, LTRs and simple repeats and LINEs formed the largest components and SINEs were very rare. Phylogenomics (370,877 amino acids) placed H. duospinosa within the Neanuridae. We recovered orthologs of the conserved sex determination genes thought to play a role in sex determination. Analysis of CpG content suggested the absence of DNA methylation, and consistent with this we were unable to detect orthologs of the DNA methyltransferase enzymes. The small subunit rRNA gene contained a possible retrotransposon. The Hox gene complex was broken over two scaffolds. For chemosensory ability, at least 15 and 18 ionotropic glutamate and gustatory receptors were identified, respectively. However, we were unable to identify any odorant receptors or their obligate co-receptor Orco. Twenty-three chitinase-like genes were identified from the assembly. Members of this multigene family may play roles in the digestion of fungal cell walls, a common food source for these saproxylic organisms. We also detected 59 and 96 genes that blasted to bacteria and fungi, respectively, but were located on scaffolds that otherwise contained arthropod genes. CONCLUSIONS: The genome of H. duospinosa contains some unusual features including a Hox complex broken over two scaffolds, in a different manner to other arthropod species, a lack of odorant receptor genes and an apparent lack of environmentally responsive DNA methylation, unlike many other arthropods. Our detection of candidate horizontal gene transfer candidates confirms that this phenomenon is occurring across Collembola. These findings allow us to narrow down the regions of the arthropod phylogeny where key innovations have occurred that have facilitated the evolutionary success of Hexapoda.

Proficiency in identifying, managing and communicating medical errors: feasibility and validity study assessing two core competencies.

BACKGROUND: Communication skills and professionalism are two competencies in graduate medical education that are challenging to evaluate. We aimed to develop, test and validate a de novo instrument to evaluate these two competencies. METHODS: Using an Objective Standardized Clinical Examination (OSCE) based on a medication error scenario, we developed an assessment instrument that focuses on distinctive domains [context of discussion, communication and detection of error, management of error, empathy, use of electronic medical record (EMR) and electronic medical information resources (EMIR), and global rating]. The aim was to test feasibility, acceptability, and reliability of the method. RESULTS: Faculty and standardized patients (SPs) evaluated 56 trainees using the instrument. The inter-rater reliability of agreement between faculty was substantial (Fleiss k = 0.71) and intraclass correlation efficient was excellent (ICC = 0.80). The measured agreement between faculty and SPs evaluation of resident was lower (Fleiss k = 0.36). The instrument showed good conformity (ICC = 0.74). The majority of the trainees (75 %) had satisfactory or higher performance in all six assessed domains and 86 % found the OSCE to be realistic. Sixty percent reported not receiving feedback on EMR use and asked for subsequent training. CONCLUSION: An OSCE-based instrument using a medical error scenario can be used to assess competency in professionalism, communication, using EMRs and managing medical errors.

Mutational analysis of cysteine residues of the insect odorant co-receptor (Orco) from Drosophila melanogaster reveals differential effects on agonist- and odorant-tuning receptor-dependent activation.

Insect odorant receptors are heteromeric odorant-gated cation channels comprising a conventional odorant-sensitive tuning receptor (ORx) and a highly conserved co-receptor known as Orco. Orco is found only in insects, and very little is known about its structure and the mechanism leading to channel activation. In the absence of an ORx, Orco forms homomeric channels that can be activated by a synthetic agonist, VUAA1. Drosophila melanogaster Orco (DmelOrco) contains eight cysteine amino acid residues, six of which are highly conserved. In this study, we replaced individual cysteine residues with serine or alanine and expressed Orco mutants in Flp-In 293 T-Rex cells. Changes in intracellular Ca(2+) levels were used to determine responses to VUAA1. Replacement of two cysteines (Cys-429 and Cys-449) in a predicted intracellular loop (ICL3), individually or together, gave variants that all showed similar increases in the rate of response and sensitivity to VUAA1 compared with wild-type DmelOrco. Kinetic modeling indicated that the response of the Orco mutants to VUAA1 was faster than wild-type Orco. The enhanced sensitivity and faster response of the Cys mutants was confirmed by whole-cell voltage clamp electrophysiology. In contrast to the results from direct agonist activation of Orco, the two cysteine replacement mutants when co-expressed with a tuning receptor (DmelOR22a) showed an ∼10-fold decrease in potency for activation by 2-methyl hexanoate. Our work has shown that intracellular loop 3 is important for Orco channel activation. Importantly, this study also suggests differences in the structural requirements for the activation of homomeric and heteromeric Orco channel complexes.

Pheromone receptor evolution in the cryptic leafroller species, Ctenopseustis obliquana and C. herana.

How new mate recognition systems evolve when changes are required in both the male and female components remains a conundrum. Here, we investigated the molecular basis of pheromone reception in two species of tortricid (leafroller) moth, Ctenopseustis obliquana and C. herana. Male C. obliquana are attracted to a 90:10 blend of (Z)-8-tetradecenyl acetate (Z8-14:OAc) and (Z)-5-tetradecenyl acetate (Z5-14:OAc), whereas C. herana males are attracted to Z5-14:OAc alone. We used a transcriptome sequencing approach from adult male and female antennae to identify 47 olfactory receptors (ORs) from each species and assessed their expression levels in male and female antennae using RNA-Seq counting and quantitative RT-PCR. Three male-biased and one female-biased OR were identified in C. obliquana by quantitative RT-PCR, and four male-biased and one female-biased receptor in C. herana. The male-biased receptors, CoblOR7, CoblOR30, CherOR7, CherOR30, CherOR1a and CherOR1b were tested for their ability to respond to sex pheromone components in a HEK293 cell calcium assay. CoblOR7 and CherOR7 responded to Z8-14:OAc, however, no receptor for Z5-14:OAc was identified. In addition to Z8-14:OAc, CherOR7 also responded to Z7-14:OAc, indicating that this receptor may be under relaxed constraint. Of the 29 amino acid differences between CoblOR7 and CherOR7, significantly more are located in the third and the sixth transmembrane domain regions. Overall, these findings are consistent with studies revealing the presence of neurons tuned to both Z8-14:OAc and Z5-14:OAc in both species, but that for C. herana males, the ability to detect Z8-14:OAc is currently not required.

Using multilayer perceptron computation to discover ideal insect olfactory receptor combinations in the mosquito and fruit fly for an efficient electronic nose.

The model organism, Drosophila melanogaster, and the mosquito Anopheles gambiae use 60 and 79 odorant receptors, respectively, to sense their olfactory world. However, a commercial "electronic nose" in the form of an insect olfactory biosensor demands very low numbers of receptors at its front end of detection due to the difficulties of receptor/sensor integration and functionalization. In this letter, we demonstrate how computation via artificial neural networks (ANNs), in the form of multilayer perceptrons (MLPs), can be successfully incorporated as the signal processing back end of the biosensor to drastically reduce the number of receptors to three while still retaining 100% performance of odorant detection to that of a full complement of receptors. In addition, we provide a detailed performance comparison between D. melanogaster and A. gambiae odorant receptors and demonstrate that A. gambiae receptors provide superior olfaction detection performance over D. melanogaster for very low receptor numbers. The results from this study present the possibility of using the computation of MLPs to discover ideal biological olfactory receptors for an olfactory biosensor device to provide maximum classification performance of unknown odorants.

The Context of Chemical Communication Driving a Mutualism.

Recent work suggests that Drosophila and Saccharomyces yeasts may establish a mutualistic association, and that this is driven by chemical communication. While individual volatiles have been implicated in the attraction of D. melanogaster, the semiochemicals affecting the behavior of the sibling species D. simulans are less well characterized. Here, we scrutinized a broad range of volatiles produced by attractive and repulsive yeasts to experimentally evaluate the chemical nature of communication between these species. When grown in liquid or on agar-solidified grape juice, attraction to S. cerevisiae was driven primarily by 3-methylbutyl acetate (isoamyl acetate) and repulsion by acetic acid, a known attractant to D. melanogaster (also known as vinegar fly). By using T-maze choice tests and synthetic compounds, we showed that these responses are strongly influenced by compound concentration. Moreover, the behavioral response is impacted further by the chemical context of the environment. Thus, chemical communication between yeasts and flies is complex, and is not driven simply by the presence of single volatiles, but modulated by compound interactions. The ecological context of chemical communication needs to be taken into consideration when testing for ecologically realistic responses.

Sex pheromone evolution is associated with differential regulation of the same desaturase gene in two genera of leafroller moths.

Chemical signals are prevalent in sexual communication systems. Mate recognition has been extensively studied within the Lepidoptera, where the production and recognition of species-specific sex pheromone signals are typically the defining character. While the specific blend of compounds that makes up the sex pheromones of many species has been characterized, the molecular mechanisms underpinning the evolution of pheromone-based mate recognition systems remain largely unknown. We have focused on two sets of sibling species within the leafroller moth genera Ctenopseustis and Planotortrix that have rapidly evolved the use of distinct sex pheromone blends. The compounds within these blends differ almost exclusively in the relative position of double bonds that are introduced by desaturase enzymes. Of the six desaturase orthologs isolated from all four species, functional analyses in yeast and gene expression in pheromone glands implicate three in pheromone biosynthesis, two Δ9-desaturases, and a Δ10-desaturase, while the remaining three desaturases include a Δ6-desaturase, a terminal desaturase, and a non-functional desaturase. Comparative quantitative real-time PCR reveals that the Δ10-desaturase is differentially expressed in the pheromone glands of the two sets of sibling species, consistent with differences in the pheromone blend in both species pairs. In the pheromone glands of species that utilize (Z)-8-tetradecenyl acetate as sex pheromone component (Ctenopseustis obliquana and Planotortrix octo), the expression levels of the Δ10-desaturase are significantly higher than in the pheromone glands of their respective sibling species (C. herana and P. excessana). Our results demonstrate that interspecific sex pheromone differences are associated with differential regulation of the same desaturase gene in two genera of moths. We suggest that differential gene regulation among members of a multigene family may be an important mechanism of molecular innovation in sex pheromone evolution and speciation.

Niche construction initiates the evolution of mutualistic interactions.

Niche construction theory explains how organisms' niche modifications may feed back to affect their evolutionary trajectories. In theory, the evolution of other species accessing the same modified niche may also be affected. We propose that this niche construction may be a general mechanism driving the evolution of mutualisms. Drosophilid flies benefit from accessing yeast-infested fruits, but the consequences of this interaction for yeasts are unknown. We reveal high levels of variation among strains of Saccharomyces cerevisiae in their ability to modify fruits and attract Drosophila simulans. More attractive yeasts are dispersed more frequently, both in the lab and in the field, and flies associated with more attractive yeasts have higher fecundity. Although there may be multiple natural yeast and fly species interactions, our controlled assays in the lab and field provide evidence of a mutualistic interaction, facilitated by the yeast's niche modification.

Odor memories regulate olfactory receptor expression in the sensory periphery.

Odor learning induces structural and functional modifications throughout the olfactory system, but it is currently unknown whether this plasticity extends to the olfactory receptors (Or) in the sensory periphery. Here, we demonstrate that odor learning induces plasticity in olfactory receptor expression in the honeybee, Apis mellifera. Using quantitative RT-PCR analysis, we show that six putative floral scent receptors were differentially expressed in the bee antennae depending on the scent environment that the bees experienced. Or151, which we characterized using an in vitro cell expression system as a broadly tuned receptor binding floral odorants such as linalool, and Or11, the specific receptor for the queen pheromone 9-oxo-decenoic acid, were significantly down-regulated after honeybees were conditioned with the respective odorants in an olfactory learning paradigm. Electroantennogram recordings showed that the neural response of the antenna was similarly reduced after odor learning. Long-term odor memory was essential for inducing these changes, suggesting that the molecular mechanisms involved in olfactory memory also regulate olfactory receptor expression. Our study demonstrates for the first time that olfactory receptor expression is experience-dependent and modulated by scent conditioning, providing novel insight into how molecular regulation at the periphery contributes to plasticity in the olfactory system.

Divergent transcriptional responses to low temperature among populations of alpine and lowland species of New Zealand stick insects (Micrarchus).

In widespread and genetically structured populations, temperature variation may lead to among-population differentiation of thermal biology. The New Zealand stick insect genus Micrarchus contains four species that inhabit different thermal environments, two of which are geographically widespread. RNA-Seq and quantitative PCR were used to investigate the transcriptional responses to cold shock among lowland and alpine species to identify cold-responsive transcripts that differ between the species and to determine whether there is intraspecific geographical variation in gene expression. We also used mitochondrial DNA, nuclear 28S ribosomal DNA and transcriptome-wide SNPs to determine phylogeographic structure and the potential for differences in genetic backgrounds to contribute to variation in gene expression. RNA-Seq identified 2160 unigenes that were differentially expressed as a result of low-temperature exposure across three populations from two species (M. hystriculeus and M. nov. sp. 2), with a majority (68% ± 20%) being population specific. This extensive geographical variation is consistent across years and is likely a result of background genetic differences among populations caused by genetic drift and possibly local adaptation. Responses to cold shock shared among alpine M. nov. sp. 2 populations included the enrichment of cuticular structure-associated transcripts, suggesting that cuticle modification may have accompanied colonization of low-temperature alpine environments and the development of a more cold-hardy phenotype.

A novel fatty acyl desaturase from the pheromone glands of Ctenopseustis obliquana and C. herana with specific Z5-desaturase activity on myristic acid.

Sexual communication in the Lepidoptera typically involves a female-produced sex pheromone that attracts males of the same species. The most common type of moth sex pheromone comprises individual or blends of fatty acyl derivatives that are synthesized by a specific enzymatic pathway in the female's pheromone gland, often including a desaturation step. This reaction is catalyzed by fatty acyl desaturases that introduce double bonds at specific locations in the fatty acid precursor backbone. The two tortricid moths, Ctenopseustis obliquana and C. herana (brown-headed leafrollers), which are endemic in New Zealand, both use (Z)-5-tetradecenyl acetate as part of their sex pheromone. In C. herana, (Z)-5-tetradecenyl acetate is the sole component of the pheromone. Labeling experiments have revealed that this compound is produced via an unusual Δ5-desaturation of myristic acid. Previously six desaturases were identified from the pheromone glands of Ctenopseustis and its sibling genus Planotortrix, with one differentially regulated to produce the distinct blends used by individual species. However, none were able to conduct the Δ5-desaturation observed in C. herana, and presumably C. obliquana. We have now identified an additional desaturase gene, desat7, expressed in the pheromone glands of both Ctenopseustis species, which is not closely related to any previously described moth pheromone desaturase. The encoded enzyme displays Δ5-desaturase activity on myristic acid when heterologously expressed in yeast, but is not able to desaturate any other fatty acid (C8-C16). We conclude that desat7 represents a new group of desaturases that has evolved a role in the biosynthesis of sex pheromones in moths.

Physician Health Series Part One: Characteristics of Physicians as Patients.

This is the first article of a 3-part series about physician health. In this installment, we outline the unique characteristics of physicians as patients, challenges and opportunities presented by physician-patients, and recommendations for treating physicians. Future articles will delve into role clarity, occupational considerations, mental health, and interactions with third parties such as the physician's employer or licensing board. Ultimately, this series will help treating clinicians provide the best care to their physician-patients and successfully navigate the unique challenges that may arise, especially when the diagnosis may have an impact on their ability to practice medicine.