PaperPlayer biorxiv zoology

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.11.246710v1?rss=1 Authors: Turner, T. L. Abstract: Sponges (phylum Porifera) are common inhabitants of kelp forest ecosystems in California, but their diversity and ecological importance are poorly characterized in this biome. Here I use freshly collected samples to describe the diversity of the order Scopalinida in California. Though previously unknown in the Eastern Pacific Ocean, four new species are described here: Scopalina nnnn1 sp. nov., S. kkkk sp. nov., S. gggg sp. nov., and S. jjjj sp. nov.. These discoveries illustrate the considerable uncharacterized sponge diversity remaining in California kelp forests, and the utility of SCUBA-based collection to improve our understanding of this diversity. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.11.246058v1?rss=1 Authors: Meijaard, E., Ni'matullah, S., Dennis, R., Hadisiswoyo, P., Sherman, J., O., O., Wich, S. A. Abstract: The Tapanuli orangutan ( Pongo tapanuliensis ) is the most threatened great ape species in the world. It is restricted to an area of about 1,000 km 2 of mostly hill forest where fewer than 800 animals survive in three declining subpopulations. Through a historical ecology approach involving analysis of colonial-era and other literature, we demonstrate that historically the Tapanuli orangutan lived in a much larger area, and across a much wider range of habitat types compared to now. Its current range is about 10-20% of the range it had some 150-200 years ago. A combination of historic fragmentation of forest habitats, mostly for small-scale agriculture, and unsustainable hunting likely drove various populations to the south, east and west of the current population to extinction prior to the industrial-scale forest conversion that started in the 1970s. Our findings indicate how sensitive orangutans are to the combined effects of habitat fragmentation and unsustainable mortality or rescue and translocation rates. Saving this species will require prevention of any further fragmentation and any killings or other removal of animals from the remaining population. Without concerted action to achieve this, the remaining populations of Tapanuli orangutan are doomed to become extinct within the foreseeable future. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.11.246009v1?rss=1 Authors: WANG, L., Wang, Q., Cai, H., Wang, H., Huang, Y., Feng, Y., Bai, X., Qin, M., Manguin, S., Gavotte, L., Wu, W., Frutos, R. Abstract: Human echinococcosis is present worldwide but it is in China that prevalence is the highest. Western China and in particular the Tibetan plateau is the region where the burden of echinococcosis is the most important. Dogs are a major carrier of echinococcosis and monitoring the presence of Echinococcus worms in dogs is therefore essential for efficiently controlling the disease. Detection kits based on three different technologies, i.e. sandwich ELISA, ELISA and gold immunodiffusion are currently marketed and used in China. The objective of this work was to assess the efficacy of these kits, in particular with respect to sensitivity and specificity. Four fecal antigen detection kits for canine echinococcosis covering the three technologies were obtained from companies and tested in parallel on 220 fecal samples. The results indicate that the performance is lower than expected, in particular in terms of sensitivity. The best results were obtained with the sandwich ELISA technology. The gold immunofiltration yielded the poorest results. In all cases, further development is needed to improve the performance of these kits, which represent a key element for the control of echinococcosis. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.09.243238v1?rss=1 Authors: DuBay, S., Palmer, D. H., Piland, N. Abstract: Linnaean taxonomy is a cornerstone of Western biology in which organisms are given a two-part name (a genus and species), creating biological units that help us order and manage our knowledge of the living world. In this system, the names of species themselves take on additional functions, such as describing features of the organism or honoring individuals (known as eponyms). Here, we interrogate how power and authority over the natural world are claimed through Western scientific naming practices to evaluate the legacies of imperialism, dispossession, and exclusion in these practices. We compile and analyze a dataset of all bird species descriptions from 1950 to present, asking: who has access and power to name species, and who is honored in species names? We show that 95% of newly described species are described from the global South, but the majority of species and eponyms are described by authors, and named after individuals, from the global North. We find an increase through time in authors from the global South, which is associated with a rise in eponyms that honor individuals from global South countries. However, this formal inclusion of global South authors has not translated into increases in first authorship (a primary form of credit and authority in Western science). We contextualize these disparities in naming and authorship within broader global structures of access and power put in place through centuries of European and U.S. imperialism, but a historical perspective alone ignores institutional and individual agency and incentives in present-day actions. As we increasingly reflect on the social foundations and impacts of our science, these findings show how research and labor in the global South continue to be disproportionately translated into power and authority in the global North, upholding and re-enacting imperial structures of domination. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.06.240002v1?rss=1 Authors: Blackwell, T., Ford, A. G. P., Ciezarek, A. G., Bradbeer, S. J., Gracida Juarez, C. A., Ngatunga, B. P., Shechonge, A. H., Tamatamah, R., Etherington, G. J., Haerty, W., Di Palma, F., Turner, G. F., Genner, M. J. Abstract: Invasive freshwater fish systems are known to readily hybridize with indigenous congeneric species, driving loss of unique and irreplaceable genetic resources. Here we reveal that newly discovered (2013-2016) evolutionarily significant populations of Korogwe tilapia (Oreochromis korogwe) from southern Tanzania are threatened by hybridization with the larger invasive Nile tilapia (Oreochromis niloticus). We use a combination of morphology, microsatellite allele frequencies and whole genome sequences to show that O. korogwe from southern lakes (Nambawala, Rutamba and Mitupa) are distinct from geographically-disjunct populations in northern Tanzania (Zigi River and Mlingano Dam). We also provide genetic evidence of O. korogwe x niloticus hybrids in three lakes and demonstrate heterogeneity in the extent of admixture across the genome. Finally, using the least admixed genomic regions we estimate that the northern and southern O. korogwe populations most plausibly diverged approximately 140,000 years ago, suggesting that the geographical separation of the northern and southern groups is not a result of a recent translocation, and instead these populations represent independent evolutionarily significant units. We conclude that these newly-discovered and phenotypically unique cichlid populations are already threatened by hybridization with an invasive species, and propose that these irreplaceable genetic resources would benefit from conservation interventions. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.07.241141v1?rss=1 Authors: Wrey, M. C., Skaar, J. C., Cates, S. B., Bollman, S. R., Fuentes, C., Blouin, M. Abstract: Hatchery reared salmonid fish often have lower fitness than their natural-origin counterparts when spawning in the wild. Although this difference appears to result from rapid adaptation to captivity, it is not known what traits are under selection. We hypothesize that variation in traits that confer a growth rate advantage to some individuals in the novel hatchery environment are under strong selection because survival at sea is correlated with size at release. Here we show that full sibling families of steelhead trout ( Oncorhynchus mykiss ) show substantial variation in propensity to feed at the surface as fry, and that the more surface-oriented families grew faster under hatchery conditions. We hypothesize that surface-oriented fry gain an initial growth advantage that persists through size at release. Because surface orientation is a correlate of generalized boldness, hatcheries may inadvertently select for that phenotype, which could explain the fitness differences observed between hatchery and natural-origin fish in the wild. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.04.236828v1?rss=1 Authors: Tam, J. Abstract: Currently, the most effective mosquito repellents employ the use of the chemical N, N-Diethyl-meta-toluamide (DEET), often considered the gold standard of repellents. However, as DEET continues to be widely used, it is beginning to lose efficacy as mosquitoes gradually gain resistance to it. Additionally, DEET only protects the skin that it is applied on, and therefore, it is difficult to achieve 100% repellency for the entire body. As urbanization and climate change continue to increase the threat of widespread mosquito-borne illnesses, new forms of repellents must be developed to combat the possibility of an epidemic. Previous studies indicate that a multitude of insects, including spiders, flies, and mosquitoes, avoid electrostatic fields at sufficiently high voltages. In this study, I evaluate if electrostatic fields can be used as a potential personal repellent against mosquitoes and an alternative to chemical sprays. I found that by charging the surface of a person's body with a high voltage (9800V) but minuscule current, I created a safe and effective method that repels mosquitoes from landing on the skin. This method has similar efficacy to DEET, with near 100% repellency after 20 minutes of charging. It also has the advantage of not needing to be reapplied and provides full-body protection, allowing greater protection to the user than DEET. These results introduce a promising method of repelling mosquitoes, that used together with present-day chemical repellents, can help provide greater protection to malaria-endemic countries. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.04.236539v1?rss=1 Authors: Josek, T., Sperrazza, J., Alleyne, M., Syed, Z. Abstract: The black-legged tick, Ixodes scapularis (Ixodida, Ixodidae), is one of the major disease vectors in the United States and due to multiple human impact factors, such as decreasing forest size for land development and climate change, it has expanded its range and established across the United States. Throughout the life cycle, ticks locate hosts for their blood-meal and although the ecologies of this tick and their hosts have been studied in depth, the sensory physiology behind host location largely remains unexplored. Here we report establishing a robust paradigm to isolate and identify odors from the natural milieu for I. scapularis. We performed single sensillum recordings (SSR) from the olfactory sensilla on the tick tarsi, and used the SSR system as biological detector to isolate natural compounds that elicited biological activity. The SSR setup was further tested in tandem with gas chromatography (GC) wherein the ticks olfactory sensillum activity served as a biological detector. The GC-SSR recordings from the wall pore sensilla in the Hallers organ, and further identification of the biologically active deer glad constituents by GC-mass spectrometry (GC-MS) revealed methyl substituted phenols as strong chemostimuli, as compared to ethyl or propyl substitutions. Strongest electrophysiological activity was elicited by meta-cresol followed by para-cresol. Ethyl- and propylphenols with any of the three, ortho, meta or para substitutions, did not induce any neurophysiological activity. Finally, a behavioral analysis in a dual-choice olfactometer of all these phenols at three different doses revealed no significant behavioral response, except for p- cresol at -3 dilution Overall, this study contributes to our understanding of I. scapularis ticks neurophysiology and provides a robust platform to isolate and identify natural attractants and repellents. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.03.234385v1?rss=1 Authors: Graham, Z. A., Palaoro, A. V. Abstract: In many species, males possess specialized weaponry that have evolved to confer a benefit during aggressive interactions. Because male weaponry is typically an exaggerated or extreme version of pre-existing body parts, females often possess reduced or weaponry. Although much research has investigated sexual dimorphism in the sizes of such weapons, other weapon components, such as weapon performance or alternative weapon forms can also explain the evolution of weapon sexual dimorphisms. Here, we investigated the allometry and variation of multiple weapon components of hindleg weaponry in the male and female giant mesquite bugs, Thasus necalifornicus. Despite theory predicating greater allocation in male weaponry, we found that females allocated more into the lengths of their hindlegs compared to males. Despite this allocation, males possess relatively wider hindlegs, which likely increase area of muscle mass. Indeed, the squeezing performance of male hindlegs was much greater than that of female hindlegs. Lastly, we also described the allometry and variation in a male weapon component, prominent tibial spines, which likely are used to damage competitors during aggressive interaction. Overall, our findings highlight the intricacies of weapon sexual dimorphism and demonstrate the importance of measuring multiple weapon components and not a single measure. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.02.232728v1?rss=1 Authors: Bhakat, S. Abstract: Travassosinema bengalensis n. sp. is described from the hind gut of the spirobolid millipede, Trigoniulus corallinus (Gervais) from West Bengal, India. Females of the new species differ from the only known Indian species, T. travassosi Rao, 1958 by several characters namely tail length, length of oesophagous, size of egg, extension of umbraculum etc. It is very similar to other three species of Travassosinema, T. travassosi, T. thyropygi Hunt, 1996 and T. claudiae Morffe & Hasegawa, 2017 as all of them lack lateral alae and body contraction posterior to vulva. Except T. claudiae, it differs from all other species from millipedes by longest tail length (60% SL) and differs from T. claudiae by shorter oesophagous length and location of vulva. A new method for presentation of morphometric data (in percentage to standard length) in nematode is suggested. On the basis of phylogenetic analysis, it is suggested that umbraculum bearing genera, Indiana, Pulchrocephala should be excluded from the family Travassosinematidae. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.31.230664v1?rss=1 Authors: Rossi, M. E., Avila, C., Moles, J. Abstract: Among nudibranch molluscs, the family Tritoniidae gathers taxa with unclear phylogenetic position, such as some species of the genus Tritonia Cuvier, 1798. Currently, 35 valid species belong to this genus and only three of them are found in the Southern Ocean, namely T. challengeriana Bergh, 1884, T. dantarti Ballesteros & Avila, 2006, and T. vorax (Odhner, 1926). In this study, we shed light on the long-term discussed systematics and taxonomy of Antarctic Tritonia species using morpho-anatomical and molecular techniques. Samples from the Weddell Sea and Bouvet Island were dissected and prepared for scanning electron microscopy. The three molecular markers COI, 16S, and H3 were sequenced and analysed through maximum likelihood and Bayesian methods. The phylogenetic analyses and species delimitation tests clearly distinguished two species, T. challengeriana and T. dantarti, being widely-spread in the Southern Ocean, and endemic to Bouvet Island, respectively. Coloration seemed to be an unreliable character to differentiate among species since molecular data revealed both species can either have orange or white colour-morphotypes. This variability could be explained by pigment sequestration from the soft coral species they feed on. Morphological analyses reveal differences between Antarctic and Magellanic specimens of T. challengeriana, thus, we suggest the resurrection of T. antarctica Martens & Pfeffer, 1886 to encompass exclusively the Antarctic species. To progress further, additional molecular data from Magellanic specimens are required to definitely resolve their taxonomy and systematics. Key words: Phylogenetic analyses, Southern Ocean, species delimitation tests, Tritoniidae taxonomy. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.29.227074v1?rss=1 Authors: Hayward, A., Skuce, P. J., McNeilly, T. N. Abstract: Liver flukes (Fasciola spp) are important parasites of sheep and cattle across the world, causing significant damage to animal health and productivity due to both acute and chronic infection. Many comprehensive reviews have discussed the results of decades of research into the impact of fluke infection on livestock performance traits such as weight gain and milk production. While fluke are considered to be important, there have been no attempts to collate previous research in a quantitative manner, and nor has there been an attempt to determine why some studies find substantial effects of fluke while others conclude that effects of fluke on animal performance are negligible. In this study, we used meta-analysis to provide quantitative estimates of the impact of liver fluke on animal performance, and to identify elements of study design that influence the conclusions of such studies. A literature search provided 233 comparisons of performance in fluke-infected and uninfected animals. We standardized these data as log response ratios and calculated effect size variances in order to weight studies by their sample size and accuracy of their estimates. We performed multi-level meta-analysis to estimate effects of fluke infection in five traits: daily weight gain (N = 77); live weight (N = 47); carcass weight (N = 84); total weight gain (N = 18) and milk production (N = 6). There were significant negative effects of fluke infection on daily weight gain, live weight and carcass weight (9%, 6% and 0.6% reductions in performance, respectively), but not total weight gain or milk production. We then used mixed-effects meta-analysis to estimate the impact of moderator variables, including host, fluke, and study design factors, on study outcomes. We found that, in general, studies that gave experimental infections found generally larger effects of fluke than observational or drug studies; younger animals were more likely to suffer the effects of fluke infection on daily weight gain; and that effects on live weight increased across the course of an experiment. Our results provide the first quantitative estimate of the importance of liver fluke on performance across studies and highlight the elements of study design that can influence conclusions. Furthermore, our literature search revealed areas of research into liver fluke that could be the subject of greater effort, and types of study that could form the basis of future meta-analyses. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.29.226423v1?rss=1 Authors: Salvador, X., Fernandez-Vilert, R., Moles, J. Abstract: Citizen science provides us with much information about charismatic taxa such as the opisthobranchs, thus contributing enormously to enlarging the geographic distribution of species. This study collects new records of elusive sea slugs and snails in the Western Mediterranean coast (especially in the Catalan coast and the French Mediterranean coast) and contributes to new ecological information regarding phenology, diet, and behaviour. Out of the 36 species reported here, 20 correspond to new records in the Catalan coast (NE Spain), three are new records of pelagic pteropods for the Spanish coast, and 10 other species are new records for the French Mediterranean coast. All records have been registered at the online database of the NGO named Catalan Opisthobranch Research Group (GROC). This study highlights the importance of sampling at night and, especially, in shallow, often-understudied waters, which usually gather high species diversity. We believe the high-quality pictures and related species' information will serve future researchers and divers find and recognize these species in the Mediterranean basin. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.27.222737v1?rss=1 Authors: Pears, J., Johanson, Z., Trinajstic, K., Dean, M., Boisvert, C. Abstract: Chondrichthyes (Elasmobranchii and Holocephali) are distinguished by their largely cartilaginous endoskeleton that comprises an uncalcified core overlain by a mineralised layer; in the Elasmobranchii (sharks, skates, rays) this mineralisation takes the form of calcified polygonal tiles known as tesserae. In recent years, these skeletal tissues have been described in ever increasing detail in sharks and rays but those of Holocephali (chimaeroids) have been less well-described, with conflicting accounts as to whether or not tesserae are present. During embryonic ontogeny in holocephalans, cervical vertebrae fuse to form a structure called the synarcual. The synarcual mineralises early and progressively, anteroposteriorly and dorsoventrally, and therefore presents a good skeletal structure in which to observe mineralised tissues in this group. Here we describe the development and mineralisation of the synarcual in an adult and stage 36 elephant shark embryo (Callorhinchus milii). Small, discrete, but irregular blocks of cortical mineralisation are present in stage 36, similar to what has been described recently in embryos of other chimaeroid taxa such as Hydrolagus, while in Callorhinchus adults, the blocks of mineralisation have become more irregular, but remain small. This differs from fossil members of the holocephalan crown group (Edaphodon), as well as from stem group holocephalans (e.g., Symmorida, Helodus, Iniopterygiformes), where tessellated cartilage is present, with tesserae being notably larger than in Callorhinchus and showing similarities to elasmobranch tesserae, for example with respect to polygonal shape. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.25.220830v1?rss=1 Authors: Ferreira Maia, M., Wagah, M. G., Karisa, J., Mwakesi, R., Mure, F., Muturi, M., Wambua, J., Hamaluba, M., Dowell, F., Bejon, P., Kapulu, M. Abstract: Background: Screening for Plasmodium spp. sporozoite infection in mosquitoes is routinely done using ELISA (enzyme-linked immunosorbent assay). Near infrared spectroscopy (NIRS), a fast and non-destructive method, has recently been shown to distinguish, with 95% accuracy, between uninfected and sporozoite-infected mosquitoes using laboratory strains of Plasmodium falciparum (PfN54). The aim of this present study was to further investigate the reproducibility of NIRS to identify sporozoite infection in mosquitoes infected using field isolates of P. falciparum gametocytes from asymptomatic carriers. Methods: Healthy individuals (aged 5 years and above) were screened for gametocytaemia by thick-smear microscopy in an area of moderate transmission along the Coast of Kenya between May and September 2018. Asymptomatic gametocyte carriers were recruited for mosquito feeding assays, direct membrane feeding (DMFA) and direct skin feeding (DFA), using insectary-reared Anopheles gambiae s.s (Kilifi strain). Mosquitoes were kept for 14-days post feeding after which they were scanned using NIRS and subsequently analysed for sporozoite infection using circumsporozoite-ELISA. Predictive models were explored using partial least square regressions (PLS). Results: Two hundred and ninety-nine (299) individuals were screened for malaria parasites, 74 (24.8%) were found with circulating asexual parasites, and 16 (5.4%) with P. falciparum gametocyte stages. Fourteen (14) asymptomatic gametocyte carriers were recruited to the study for mosquito feeding assays. A total of 134 (7%, 134/1881) sporozoite-infected mosquitoes were obtained from 9 successful experiments. Three different training datasets composed of infected and uninfected mosquitoes were analysed. The PLS models were unable to distinguish between sporozoite-infected and uninfected mosquitoes. A predictive model could not be generated. Conclusions: The results of this study were not consistent with previous published research on NIRS for detection of sporozoite infection in the same mosquito species and may reflect differences between laboratory and field conditions. The current findings indicate that methods for sporozoite detection should be tested on field isolates at an early stage in their development and are informative for future research seeking novel high-throughput methods for parasite detection in mosquitoes. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.26.221994v1?rss=1 Authors: Torres, D. A., Rojas, A. E. Abstract: The Magdalena river basin is home to more than half of Colombia's human population, and consequently the basin also harbors their economic activities. These activities have generated high deforestation rates and negative pressures on natural resources. With such a scenario of forest loss it is imperative to assess the state of the biodiversity and its conservation. Here, during six years we assessed the mammalian species richness and abundance in premontane forests of Caldas department in the Magdalena river basin. We also presented additional information on the activity patterns and geographical affinities of this fauna. We recorded 100 species of mammals with the Chiroptera as the richest order, followed by Rodentia. Most of the species are common and are not under risk of extinction; however, it is important to highlight the presence of six endemic species, three vulnerable species and one endangered species (white-footed tamarin). The mammalian fauna of this region is similar to other lowland localities in the Neotropics, and less similar to highland localities, including the nearby ones. Specifically, this fauna is most similar to lowland Tolima, and the Caribbean region of Colombia, Venezuela and Costa Rica; however, when we accounted only for bat fauna, it was more similar to the Caribbean and Pacific regions of Colombia. To secure the long-term persistence of these species we recommend maintenance of the current corridors such as riparian forests and living fences and an increase in the forested area. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.23.217836v1?rss=1 Authors: Tesicky, M., Krajzingrova, T., Elias, J., Velova, H., Svobodova, J., Bauerova, P., Albrecht, T., Vinkler, M. Abstract: While seasonal trends in the testosterone-driven hormonal regulation of resource allocation are known from cohort population samples, data on the inter-annual individual stability of blood plasma testosterone levels in wild birds are lacking, and our understanding of age-dependent changes is limited. We assessed plasma testosterone levels in 105 samples originating from 49 repeatedly captured free-living great tits (Parus major) to investigate their relative long-term stability and lifetime changes. Furthermore, we examined the inter-annual stability of selected condition-related traits (carotenoid- and melanin-based plumage ornamentation, ptilochronological feather growth rate, body mass, and haematological heterophil/lymphocyte ratio) and their relationships to testosterone levels. We show that testosterone levels in both sexes are inter-annually repeatable, both in their absolute values and individual ranks (indicating the maintenance of relative status in a population), yet with higher stability in females. Despite this stability, in males we found a quadratic dependence of testosterone levels on age, with a peak in midlife. In contrast, female testosterone levels showed no lifetime trend. The inter-annual stability of condition-related traits was mostly moderate and unrelated to plasma testosterone concentrations. However, males with elevated testosterone had significantly higher carotenoid-pigmented yellow plumage brightness, presumably serving as a sexually selected trait. Showing inter-annual stability in testosterone levels, this research opens the way to further understanding of the causes of variation in fitness-related traits. Based on a unique longitudinal dataset, this study demonstrates that male plasma testosterone undergoes age-related changes that may regulate resource allocation. Our results thus demonstrate that male birds undergo hormonal senescence similar to mammals. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.24.219311v1?rss=1 Authors: Whiteland, H., Crusco, A., Tibble-Howlings, J., Forde Thomas, J., Bloemberg, L. W., Coghlan, A., Murphy, P., Hoffmann, K. F. Abstract: Background Schistosomiasis is a prevalent neglected tropical disease that affects approximately 300 million people worldwide. Its treatment is through a single class chemotherapy, praziquantel. Concerns surrounding the emergence of praziquantel insensitivity have led to a need for developing novel anthelmintics. Methodology/Principle findings Through evaluating and screening fourteen compounds (initially developed for anti-cancer and anti-viral projects) against Schistosoma mansoni, one of three species responsible for most cases of human schistosomiasis, a racemic N-acyl homoserine ( 1 ) demonstrated good efficacy against all intra mammalian lifecycle stages including schistosomula (EC 50 = 4.7 {micro}M), juvenile worms (EC 50 = 4.3 {micro}M) and adult worms (EC 50 = 8.3 {micro}M). To begin exploring structural activity relationships, a further 8 analogues of this compound were generated, including individual ( R )- and ( S )- enantiomers. Upon anti-schistosomal screening of these analogues, the ( R )- enantiomer retained activity, whereas the ( S )- lost activity. Furthermore, modification of the lactone ring to a thiolactone ring ( 3 ) improved potency against schistosomula (EC 50 = 2.1 {micro}M), juvenile worms (EC 50 = 0.5 {micro}M) and adult worms (EC 50 = 4.8 {micro}M). As the active racemic parent compound is structurally similar to quorum sensing signaling peptides used by bacteria, further evaluation of its effect (along with its stereoisomers and the thiolactone analogues) against Gram + ( Staphylococcus aureus ) and Gram - ( Escherichia coli ) species was conducted. While some activity was observed against both Gram + and Gram - bacteria species for the racemic compound 1 (MIC 125 mg/L), the ( R ) stereoisomer had better activity (125 mg/L) than the ( S ) (>125mg/L). However, the greatest antimicrobial activity (MIC 31.25 mg/L against S. aureus ) was observed for the thiolactone containing analogue ( 3 ). Conclusion/Significance To the best of our knowledge, this is the first demonstration that N-Acyl homoserines exhibit anthelmintic activities. Furthermore, their additional action on Gram + bacteria opens a new avenue for exploring these molecules more broadly as part of future anti-infective initiatives. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.22.215624v1?rss=1 Authors: Marialva, E. F., Secundino, N. F. C., Fernandes, F. F., Araujo, H. R., Rios-Velasquez, C. M., Pimenta, P. F., Pessoa, F. A. C. Abstract: We describe the immature stages of Migonemyia migonei, which is the vector of Leishmania (Viannia) braziliensis, the aetiological agent of cutaneous leishmaniasis in South America, and a putative vector of Leishmania infantum chagasi. Scanning Electron Microscopy (SEM) was used to refine the description of the structures of eggs, all instar larvae and pupa. The eggs have polygonal cells on the egg exochorion, and differences between larval and pupal chaetotaxy are highlighted. Different sensillary subtypes were observed in the larval stages, among the types trichoidea, basiconica, coelonica and campanoformia. These results contribute to the taxonomy of Mg. migonei and may contribute to future studies on the phylogeny of this important species vector. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.21.214056v1?rss=1 Authors: Ong, S.-Q., Ahmad, H., Mohd. Ngesom, A. M. Abstract: The impact of movement restrictions (MRs) during the COVID-19 lockdown on the existing endemic infectious disease dengue fever has generated considerable research interest. We compared the curve of weekly epidemiological records of dengue incidences during the period of lockdown to the trend of previous years (2015 to 2019) and a simulation at the corresponding period that expected no MRs and found that the dengue incidence declined significantly with a greater magnitude at phase 1 of lockdown, with a negative gradient of 3.2-fold steeper than the trend observed in previous years, indicating that the control of population movement did reduce dengue transmission. However, starting from phase 2 of lockdown, the dengue incidences demonstrated an elevation and earlier rebound by 4 weeks and grew with an exponential pattern. Together with our data on Aedes mosquitoes, we proposed a stronger diffusive effect of vector dispersal that led to a higher rate of transmission. From the result of the Aedes survey using human landing caught (HLC), we revealed that Aedes albopictus is the predominant species for both indoor and outdoor environments, with the abundance increasing steadily during the period of lockdown. We only recovered Aedes aegypti from the indoor environment, which is relatively fewer than Ae. albopictus, by contrasting their population growth, which suggested that Ae. albopictus invaded and colonized the habitat of Ae. aegypti during the period of lockdown. These findings would help authorities review the direction and efforts of the vector control strategy. Author summaryCOVID-19 pandemic is taking hold globally and dengue fever transmission is not on the top of the list of concerns. With a partial lockdown implemented by Malaysia on 18 March, we postulate the movement restrictions (MRs) of people in large-scale would hamper the regular dengue transmission and aim to reveal the impact of MRs on both dengue incidences and Aedes mosquitoes. We showed a significant decline of dengue incidences at the beginning of lockdown but later rebounded at an earlier time and higher rate compared to the corresponding period of previous years. Our result also reviews how adaptive the Ae. albopictus with the movement of the host, as the human contained in the house, the abundance of the mosquitoes increased significantly during the period of lockdown. We also suggest that Ae. albopictus could be the key substitution vector that contributes significantly to dengue virus circulation, and therefore, the vector control direction and strategies should be redesigned. Copy rights belong to original authors. Visit the link for more info