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At least 145 records · Page 8Linked to original sources

bioRxiv2017

Changes in free amino acid concentrations and associated gene expression profiles in the abdominal muscle of kuruma shrimp Marsupenaeus japonicus reared at different salinity

Shrimps inhabiting around the coastal area can survive in a wide range of salinity. However, the molecular mechanisms involved in their adaptation to different environmental salinity have remained largely unknown. In the present study, we reared kuruma shrimp Marsupenaeus japonicus at 1.7 %, 3.4 % and 4.0 % salinity. After rearing for 6, 12, 24 and 72 h, we determined free amino acid concentrations in their abdominal muscle, and performed RNA-seq analysis on this muscle. The concentrations of free amino acids were clearly altered depending on salinity after rearing for 24 h. Glutamine and alanine concentrations were markedly increased following the increase of salinity. In association with such changes, many genes related to amino acid metabolism changed their expression levels. Notably, the increased glutamine content at high salinity appeared to be relevant to the increase of the expression level of the gene encoding glutamate-ammonia ligase which functions in the glutamine metabolism. Furthermore, the alanine content increased at high salinity was likely to be associated with the decrease in the expression levels of the alanine-glyoxylate transaminase gene. Thus, the changes in the concentration of free amino acids for osmoregulation in kuruma shrimp are considered to be regulated by the changes in the expression levels of genes related to amino acid metabolism.\n\nSummary statesmentKuruma shrimp Marsupenaeus japonicus changes free amino acid contents and associated gene expression levels in their muscle to adjust effectively to different salinity.

zoology↗

bioRxiv2017

Behavioral and Hematological Response of Clarias gariepinus juvenile exposed to Acute concentrations of Aqueous Extract of Siam Weed (Chloromolaena odorata) leaf as Anesthetic agent

This experiment was carried out to investigate the effect of Siam Weed (chloromelena odorata) on the heamatology of Clarias gariepinus juvenile. A total of one hundred and fifty (150) juvenile of Clarias gariepinus were randomly assigned to different concentrations of C. odorata leave aqueous extract in a completely randomize design (CRD). The concentrations were 50mg/l, 100mg/l, 150mg/l, 200mg/l. Distilled water (0.00 mg/l) was used as the control. The fish exhibited stressful behavior which was higher as the concentration of Chromolaena odorata leave extract increased. There was a gradual decrease with time until a state of calmness, which was subsequently followed by death. The effect on 96hr exposed period was recorded and blood samples collected at 24hr and 96hr interval. Result on hematological parameters revealed significant difference (P<0.05) among treatments with increase in exposure time for all the blood parameters. C. odorata at increased concentrations affected the behavior and hematology of C. gariepinus.

zoology↗

bioRxiv2017

Humpback whales of the Persian Gulf

The humpback whale has long been considered a rare straggler into the Persian Gulf, however new evidence contradicts this concept. We here critically review published and new records for Megaptera novaeangliae occurrence in the Gulf for the period 1883-2017. Of eight authenticated records (6 specimens, 2 live-sightings), seven are contemporary cases while one is a mid-Holocene specimen from UAE. An additional four are possible but unsubstantiated reports. Four regional, current, range states are confirmed, i.e. Iran, Iraq, Kuwait and Qatar. Four of the five newly reported cases are from Irans coastal waters. We conclude that the Persian Gulf is part of the habitual range of the Arabian Sea humpback whale population, and has been since at least the mid-Holocene. It is unknown whether frequent passage occurs through the Strait of Hormuz or whether whales are (semi)resident. The low abundance of this endangered population and frequent deleterious anthropogenic events, particularly ship strikes and net entanglements, are cause for major concern. In view of its historical and taxonomic relevance, the formal description of Megaptera indica Gervais, 1883, from Iraq, now thought to be a subspecies M. novaeangliae indica, is here translated from French.

zoology↗

bioRxiv2017

Odonata diversity of the eastern region of Bangladesh with four new addition to the Bangladeshi dragonfly fauna

A study was conducted in the eastern region to contribute to the Odonata fauna of Bangladesh. A total of 76 species belonging to 9 families have been recorded during the study period of April 2014 to July 2016. Three Zygopteran species e.g, Ceriagrion rubiae, Calicnemia imitans, Prodasineura autumnalis and one Anisopteran species e.g, Megalogomphus smithii have been newly discovered from Bangladesh. Megalogomphus genus have been first time recorded from Bangladesh.

zoology↗

bioRxiv2017

Diet predicts milk composition in primates

Mammalian mothers pay heavy energetic costs to fuel the growth of their offspring. These costs are highest during lactation. Energy transmitted to offspring in the form of milk must ultimately come from the maternal diet, but there have been few comparative studies of the relationship between milk properties and mammalian diets. We used interspecific data on primate milk composition and wild diets to establish that concentrations of milk protein and sugar are predicted by diet independent of maternal mass, litter mass, and infant parking behavior such that increasing folivory or faunivory increases protein concentration but decreases sugar concentration. Milk energy density is unrelated to diet, though infant parking species do produce more energy-dense milk. While parking effects have been previously explained as a result of mother-infant separation, the mechanisms causing the relationship between nutrient packaging in milk and maternal diet are currently unclear. However, they likely reflect evolved differences in maternal energetics related to maternal foraging ecology, infant growth patterns, or the relative dietary abundance of nutrients costly to synthesize in milk among primate species.

zoology↗

bioRxiv2017

Biomechanics of the peafowl’s crest: a potential mechanosensory role for feathers during social displays

Feathers act as vibrotactile sensors that can detect mechanical stimuli during avian flight and tactile navigation, suggesting that they may also detect stimuli during social displays. In this study, we present the first measurements of the biomechanical properties of the feather crests found on the heads of birds, with an emphasis on those from the Indian peafowl (Pavo cristatus). We show that in peafowl these crest feathers are coupled to filoplumes, small feathers known to function as mechanosensors. We also determined that airborne stimuli with the frequencies used during peafowl courtship and social displays couple efficiently via resonance to the vibrational response of their feather crests. Specifically, vibrational measurements showed that although different types of feathers have a wide range of fundamental resonant frequencies, peafowl crests are driven near-optimally by the shaking frequencies used by peacocks performing train-rattling displays. Peafowl crests were also driven to vibrate near resonance in a playback experiment that mimicked the effect of these mechanical sounds in the acoustic very near-field, reproducing the way peafowl displays are experienced at distances [≤] 1.5m in vivo. When peacock wing-shaking courtship behaviour was simulated in the laboratory, the resulting airflow excited measurable vibrations of crest feathers. These results demonstrate that peafowl crests have mechanical properties that allow them to respond to airborne stimuli at the frequencies typical of this species social displays. This suggests a new hypothesis that mechanosensory stimuli could complement acoustic and visual perception and/or proprioception of social displays in peafowl and other bird species. We suggest behavioral studies to explore these ideas and their functional implications.

zoology↗

bioRxiv2017

Cryptic phylogeographic history sheds light on the generation of species diversity in sky-island mountains

Biodiversity hotspots should be given high priority for conservation under the situation of global climate change. The sky islands in southwestern China are characterized by extraordinarily high species diversity and are among one of the worlds top biodiversity hotspots. However, neither the actual species diversity in this region or mechanisms generating this diversity are well explored. Here, we report on the phylogeographic analysis of the long-tailed mole (Scaptonyx fusicaudus), a semi-fossorial mammal that inhabits the montane cool forests across the Chinese sky islands and is considered to represent one species divided into two subspecies. Analyses using DNA sequence data from one mitochondrial and six nuclear genes revealed that populations inhabiting different mountains exhibited exceptionally strong geographic structure. The lowlands and large rivers act as \"soft\" and \"hard\" barriers to dispersal, respectively, isolating evolutionary lineages for up to 11 million years. Our results suggest that the mountain ranges act as interglacial refugia buffering populations from climate fluctuations, further facilitating allopatric diversification. Strikingly, species delimitation analyses suggests that the long-tailed mole may comprise 18 operational taxonomic units and 17 putative species. Our results suggest that for low-vagility species, the complex topography of the Chinese sky islands has shaped genetic diversity and structure and promoted exceptional diversification through a combination of eco-environmental stability as well as geographic fragmentation. The patterns observed in S. fusicaudus may be representative for other cold- adapted species, reflecting the generation of mammalian faunal diversity in the sky-island mountains of southwestern China.

zoology↗

bioRxiv2017

Placozoans are eumetazoans related to Cnidaria

The phylogenetic placement of the morphologically simple placozoans is crucial to understanding the evolution of complex animal traits. Here, we examine the influence of adding new genomes from placozoans to a large dataset designed to study the deepest splits in the animal phylogeny. Using site-heterogeneous substitution models, we show that it is possible to obtain strong support, in both amino acid and reduced-alphabet matrices, for either a sister-group relationship between Cnidaria and Placozoa, or for Cnidaria and Bilateria (=Planulozoa), also seen in most published work to date, depending on the orthologues selected to construct the matrix. We demonstrate that a majority of genes show evidence of compositional heterogeneity, and that the support for Planulozoa can be assigned to this source of systematic error. In interpreting this placozoan-cnidarian clade, we caution against a peremptory reading of placozoans as secondarily reduced forms of little relevance to broader discussions of early animal evolution.

zoology↗

bioRxiv2019

Combined salinity and acidity stressors alter Daphnia magna population growth and structure under prolonged absence of photoperiod

Although natural and anthropogenic influences affect freshwater ecosystems globally at unprecedented levels, the effects of co-occurring physico-chemical stress on zooplankton phenotypic plasticity under extreme conditions remain understudied.We exposed a laboratory-raised clonal population of Daphnia magna to different stress levels of acidity and salinity undergoing complete constant light over 30 days. Overall, population size and age structure at day 10 considerably differed between specific stress contexts. All populations expanded compared to the starting population on day 1. On day 30, overall, population size increased but showed significant differences between treatment groups. Surprisingly, Daphnia performed better under combined stress of salinity and acidity than under acidity alone as the extra salinity in the medium may have counterbalanced sodium loss caused by lower pH. Our results reveal a considerable degree of differential reproductive and ontogenetic plasticity in response to combined stressors under disrupted photoperiod. Exposure to constant light led to increased population size, which may be a result of supercharged ion regulation that enables zooplankton to survive better under specific levels of extreme environmental change and adverse chemical stress. Our findings merit further molecular investigation of phenotypic plasticity of the congeners across severe combined stress conditions.Competing Interest StatementThe authors have declared no competing interest.View Full Text

zoology↗

bioRxiv2019

Out of the Qinghai-Tibetan Plateau and get flourishing - the evolution of Neodon voles (Rodentia: Cricetidae) revealed by systematic sampling and low coverage whole genome sequencing

Neodon, genus of a short time evolutionary history, was reported to be diverged from its relatives in early stage of Pleistocene. Only 4 species were well documented in Neodon for a long period of time until last years when a systematic work described and added three new species, adjusted three species used to belong to Lasiopodomys, Phaiomys, Microtus to Neodon and removed one species (Neodon juldaschi) to genus Blanfordimys, leading to a total of eight species recorded in Neodon. To gain a better insight into the phylogeny and ecology of Neodon, we have systematically sampled Neodon species along the whole Hengduan and Himalayan Mountains in the last 20 years. In addition to morphological identification, we generated 1x - 15x whole genome sequencing (WGS) data and achieved the mitochondrial genomes and an average of 5,382 nuclear genes for each morpho-species. Both morphology and phylogeny results supported an extra six new species in Neodon (nominated Neodon shergylaensis sp. nov., N. namchabarwaensis sp. nov., N. liaoruii sp. nov., N. chayuensis sp. nov., N. bomiensis sp. nov., and N. bershulaensis sp. nov.). This is the first study that included Neodon samples covering its entire distribution area in China and this systematic sampling also revealed a long-time underestimation of Neodons diversity, and suggested its speciation events linked highly to founder event via dispersal (from Plateau to surrounding mountains). The results also revealed that the Qinghai-Tibetan Plateau is the center of origin of Neodon, and the impetus of speciation include climate change, isolation of rivers and mountains.

zoology↗

bioRxiv2019

A novel system for maintaining Varroa destructor mites on artificial diets and its application for studying mites as a vector for honey bee viruses.

The mite Varroa destructor is one of the most destructive parasites of the honey bee (Apis mellifera) and the primary cause of colony collapse in most regions of the world. These mites cause serious injury to their hosts, especially during the larval and pupal stages, and serve as the vector for several viruses, which affect honey bee health causing colony death. Attempts by beekeepers to control these mites have yielded limited success. The inability to rear populations of mites in vitro that excludes contact with their honey bee hosts has stymied research of Varroa biology. Previous attempts to rear and/or maintain Varroa mites in vitro by feeding them on artificial diets have had limited success. Several methods were plagued by mechanical failures including leaking membranes and, thus far, none have been widely adopted. Here we report a robust system for maintaining Varroa mites that includes an artificial diet, which does not contain honey bee tissue-derived components, thus making it particularly valuable in studying mite vectoring of honey bee viruses. With our system we demonstrated for the first time that Varroa mites maintained on an artificial diet supplemented with the particles of honey bee viruses, cDNA clone-derived genetically tagged Varroa destructor virus-1 and wild-type Deformed wing virus, can acquire and later transmit these viruses to recipient honey bee pupae. Along with providing an opportunity to study parasites and pathogens in the absence of honey bee hosts, this in vitro system for Varroa mite maintenance is both scalable and consistent. These features can be used to better understand mite nutritional needs, metabolic activity, responses to chemicals and other biological functions.

zoology↗

bioRxiv2019

Estimates of abundance and change in abundance of the Indo-Pacific bottlenose dolphins (Tursiops aduncus) along the south coast of South Africa

We investigated the abundance of Indo-Pacific bottlenose dolphins (Tursiops aduncus) along the south coast of South Africa, from the Goukamma Marine Protected Area (MPA) to the Tsitsikamma MPA, between 2014 and 2016. During this period, 662.3h of boat-based photo-identification survey effort was carried out, and the sighting histories of 817 identified individuals were used to estimate abundance using mark-recapture modelling. The selected open population model (POPAN) provided an estimate of 2,295 individuals (95% CI: 1,157-4,553) for the entire study area. A model estimate was produced for a subset of the study area, Plettenberg Bay, which could be compared with a past estimate for this location (2002-2003). The comparison suggested a 72.3% decrease in abundance, from 6,997 (95% CI: 5,230-9,492) in 2002-2003 to 1,940 (95% CI: 1,448-2,600) in 2014-2016. The decline in abundance was supported by a 72% reduction in mean group size for Plettenberg Bay between the periods. It is essential to be able to assess abundance changes at other locations to inform revision of T. aduncus conservation status in South Africa.

zoology↗

bioRxiv2019

Physiological and morphological correlates of extreme acid tolerance in larvae of the acidophilic amphibian Litoria cooloolensis (Anura: Pelodryadidae)

In the coastal sandy lowlands of east Australia, several anuran species including the Cooloola Sedgefrog Litoria cooloolensis, show remarkable tolerance to dilute highly acidic waters as low as pH 3.5. To investigate the physiological and morphological underpinnings of acid tolerance in L. cooloolensis larvae, we compared Na+ balance, uptake and efflux rates, and gill and skin morphology in larvae reared in circum-neutral (pH 6.5) and pH 3.5 water. We hypothesised that acute exposure to pH 3.5 water would cause an initial loss of ionic homeostasis in larvae, but with chronic exposure larvae would restore Na+ balance. Net Na+ flux rates were not significantly different from zero in larvae reared at pH 3.5 and in acid-na&iumlve animals maintained in pH 6.5 water. Animals reared at pH 6.5 and acutely exposed to pH 3.5 exhibited a net loss of Na+, due to a significant inhibition of Na+ uptake. In contrast, L. cooloolensis larvae reared at pH 3.5 maintained Na+ balance at pH 3.5 and did not exhibit inhibition of Na+ uptake at this pH. Investigation of Na+ transport kinetics and the morphology of the gills and integument suggests tolerance of L. cooloolensis larvae to low pH may be attributed to a high capacity for branchial Na+ uptake, increased tight junction length and elevated mucus production in the gills and integument. These factors confer resistance to acid damage and disruption of ionic homeostasis which would otherwise result in the death of larvae exposed to waters of pH 4.0 and less.

zoology↗

bioRxiv2019

Aberrant cocoons found on honey bee comb cells are found to be Osmia cornifrons (Radoszkowski) (Hymenoptera Megachilidae)

Potential biological threats to honey bees must be addressed and validated quickly, before making disruptive and costly decisions. Here we describe numerous Osmia cornifrons (Hymenoptera: Megachilidae) cocoons in honey bee cells from one bee hive in Ohio. The developing Osmia cells presented themselves as a mystery at first, catching the attention of regulatory agencies. Along with identifying this species as a presumably benign resident in honey bee colonies, our observations suggest Osmia may use stored honey bee resources to provision offspring. Conceivably, resident honey bees might even act as surrogates, by provisioning Osmia offspring with pollen. Since the cocoons were attached to one another with honey bee wax, it seems likely that honey bee hosts were present during Osmia development. Osmia females have some plasticity when selecting nesting resources, and, upon discovering honey bee comb can use this resource for raising offspring. Along with resolving a potentially new biotic threat to honey bees, this diagnosis suggests a method for mass production of Osmia pollinators using an array of single cell foundation.

zoology↗

bioRxiv2019

Temporal changes in post-alighting resistance to Rhopalosiphum padi (bird cherry-oat aphid) in ancestral wheats

O_LIAphids reduce wheat yield through feeding on phloem sap, inflicting direct and indirect damage to the plant. Currently no commercial wheat varieties have been bred for resistance to Rhopalosiphum padi (bird cherry-oat aphid). However, post-alighting resistance has been identified in Triticum monococcum lines at the seedling stage. C_LIO_LITo further characterise the resistance in T. monococcum at plant ages, we have investigated the development, survival and reproductive success of R. padi on two susceptible wheats Triticum aestivum (variety Solstice) and T. monococcum MDR037, as well as on the partially resistant T. monococcum MDR045 and MDR049, using one, two, 12 (flag leaf) and 20 week-old (inflorescence) plants. C_LIO_LIWe found that the host plant resistance reduced development and reproductive success in aphids. However, the effect decreased with plant age on MDR045 but increased with plant age on MDR049. C_LIO_LIThe observed resistance to aphids has strong potential for introgression into commercial wheat varieties, which could have an important role in Integrated Pest Management strategies to reduce aphid populations and virus transmission. C_LI

zoology↗

bioRxiv2019

Spatial distribution and research trend of illegal activities and the factors associated with wild mammal population declines in protected areas

Illegal activities are a persistent problem in many protected areas, but an overview of the extent of this problem and its impact is lacking. We review 35 years (1980-1914) of research across the globe to examine the spatial distribution of research and socio-ecological factors influencing population decline within protected areas under illegal activities pressure. From 92 papers reporting 1048 species/site combinations, more than 350 species comprising mammals, reptiles, birds, fishes and molluscs were reported to have been extracted illegally from 146 protected areas across four continents. Research in illegal activities has increased substantially during the review period but also shows strong taxonomic and geographic biases towards large wild mammals and African continent respectively, suggesting persistent poaching pressures on wild mammals in African protected areas. Population declines were most frequent i) where there was commercial poaching as opposed to subsistence poaching alone, ii) in countries with a low human development index particularly in strict protected areas and iii) for species with a body mass over 100 kg. Habitat loss associated with greater land use change had an additional significant impact on population decline, particularly in the less-strict categories (IUCN III-VI) of protected area across the continents. Overall, these findings provide evidence that illegal activities are most likely to cause species declines of large-bodied animals in protected areas in resource-poor countries regardless of protected area conservation status (i.e. IUCN category). Given the mounting pressures of illegal activities, additional conservation effort such as improving anti-poaching strategies and conservation resources in terms of improving funding and personnel directed at this problem is a growing priority.

zoology↗

bioRxiv2019

A long noncoding RNA acts as a post-transcriptional regulator of heat shock protein 70 kDa synthesis in the cold hardy Diamesa tonsa under heat shock

Cold stenothermal insects living in glacier-fed streams are stressed by temperature variations resulting from glacial retreat during global warming. The molecular aspects of insect response to environmental stresses remain largely unexplored. The aim of this study was to expand our knowledge of how a cold stenothermal organism controls gene expression at the transcriptional, translational, and protein level under warming conditions. Using the chironomid Diamesa tonsa as target species and a combination of RACE, qPCR, polysomal profiling, western blotting, and bioinformatics techniques, we discovered a new molecular pathway leading to previously overlooked adaptive strategies to stress. We obtained and characterized the complete cDNA sequences of three heat shock inducible 70 (hsp70) and two members of heat-shock cognate 70 (hsc70). Strikingly, we showed that a novel pseudo-hsp70 gene encoding a putative long noncoding RNA (lncRNA) which is transcribed during thermal stress, acting as a ribosome sponge to provide post-transcriptional control of HSP70 protein levels. The expression of the pseudo-hsp70 gene and its function suggest the existence of a new and unexpected mechanism to cope with thermal stress: lowering the pace of protein production to save energy and optimize resources for recovery.

zoology↗

bioRxiv2019

Zika and dengue viruses infecting wild-caught mosquitoes in an environmental protection area in Brazil

Species of the genus Flavivirus are widespread in Brazil and are a major public health concern. The city of Sao Paulo is in a highly urbanized area with some green spaces which are used for recreation and where potential vertebrate hosts and mosquito vectors of these arboviruses can be found, a scenario that can contribute to the transmission of flaviviruses to humans. This study therefore sought to investigate natural flavivirus infection in mosquitoes collected in the Capivari-Monos Environmental Protection Area (EPA) in the south of the city. Monthly mosquito collections were carried out from March 2016 to April 2017 with CO2-baited CDC light traps. Specimens were identified morphologically and grouped in pools. A total of 260 pools of non-engorged females were inoculated into the C6/36 cell lineage after analysis by indirect immunofluorescence assay (IFA). IFA-positive specimens were tested by qRT-PCR with genus-specific primers targeting a region of ~260 nucleotides in the flavivirus NS5 gene, and the PCR products were sequenced to confirm and identify the flavivirus species. Anopheles (Kerteszia) cruzii and Wyeomyia (Prosopolepis) confusa were the most frequent species collected. Zika virus (ZIKV) nucleotide sequences were detected in three mosquito species, An. cruzii, Limatus durhami and Wy. confusa, and dengue virus 2 (DENV-2) sequences in Culex. spp. and Culex. (Mel.) vaxus. To our knowledge, this is the first report of natural isolation of DENV-2 and ZIKV in sylvatic species of mosquitoes in the Capivari-Monos EPA. Our findings suggest that DENV-2 is present in Culex mosquitoes, and ZIKV in Anopheles, Wyeomyia and Limatus. The flavivirus species identified here are of medical importance; surveillance is therefore recommended in this EPA, where vertebrates and mosquitoes can act as flavivirus hosts and vectors.

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