Nature's disguise:Empirical demonstration of dead-leaf masquerade in Kallima butterflies

Animals deploy diverse color-based defenses against predators,including crypsis,mimicry,aposematism,and masquerade.While crypsis,mimicry,aposematism have been extensively studied,the strategy of masquerade-where organisms imitate inedible or inanimate objects such as leaves,twigs,stones,and bird droppings-remains comparatively underexplored,particularly in adult butterflies.The Indian oakleaf butterfly(Kallima inachus)exemplifies this phenomenon,with its wings resembling dead leaves,providing a classic example of natural selection.Although it has long been postulated that these butterflies evade predation by being misidentified as dead leaves,direct experimental evidence is lacking.In the current study,using domestic chicks as predators,we manipulated their prior experience with dead leaves(model objects)while maintaining constant exposure to butterflies to test whether dead-leaf masquerade provides a protective advantage by preventing recognition.Results showed a marked delay in the initiation of attacks by chicks familiar with dead leaves compared to those with no prior exposure or those exposed to visually altered leaves.Chicks with prior dead-leaf experience required a similar amount of time to attack the butterflies as they did to attack dead leaves.These findings provide the first empirical demonstration of dead-leaf masquerade in Kallima butterflies,shedding light on its evolutionary significance.Our study highlights the effectiveness of masquerade in inducing the misclassification of butterflies as inanimate objects,showcasing the precise mimicry achieved by these organisms when viewed in isolation from the model objects.This study advances our understanding of the evolution of masquerade and its role as a potent antipredator strategy in nature.

Regulation of aging by NELF-A and RNA polymerase Ⅱ elongation

Epigenetic regulation of aging:Aging is defined as the gradual decline of physiological function and cellular integrity,causing o rganismal vulnerability to age-onset diseases and morbidity.Studies in different animal models have led to the identification of twelve aging hallmarks that shared several features:its age-associated manifestation.

Risk Management of Cyanotoxins in Singapore

Cyanotoxins produced by cyanobacteria pose significant challenges to water resource management due to the potential impacts they have on human health. Cylindrospermopsin (CYN) and microcystins (MC) are the more commonly detected cyanotoxins in Singapore’s reservoirs. Among the MC congeners monitored locally, the most frequently detected variants are MC-RR (37.6%), followed by MC-LR (25.6%). MC-LA and MC-YR are the least frequently detected variants (7.1%). No cyanotoxins have been detected in Singapore’s treated drinking water. Singapore’s National Water Agency (PUB) and the National Environment Agency (NEA) developed recreational water quality guidelines using Chl a concentrations of 50 μg/L. In local surface waters, long-term data showed that at 50 μg/L of Chl a, MC-LR concentrations ranged from <0.025 μg/L to 1 μg/L. In addition to using Chl a concentrations, Microcystis cell counts in reservoir water have also been used to manage cyanotoxin risk in drinking water. Specifically, routinely monitored data from all 17 Singapore reservoirs indicated that to keep MC-LR concentrations below the WHO provisional guideline of 1 μg/L in drinking water, Microcystis cell counts needed to be <10,000 cells/ml. Culture experiments using local Microcystis isolates showed M. aeruginosa produced the most MC compared to M. ichthyoblabe, M. flos-aquae, and M. viridis. Based on the maximum toxin cell quota equivalent to the WHO provisional guideline for MC-LR of 1 μg/L in drinking water, a 5000 cells/ml cell count guideline was derived for M. aeruginosa. This cell count has also been incorporated into Singapore’s cyanotoxin risk management framework for reservoirs.

Structural basis for dsRNA recognition by NS1 protein of influenza A virus

Influenza A viruses are important human pathogens causing periodic pandemic threats. Nonstructural protein 1 （NS1） protein of influenza A virus （NS1A） shields the virus against host defense. Here, we report the crystal structure of NS1A RNA-binding domain （RBD） bound to a double-stranded RNA （dsRNA） at 1.7A. NS1A RBD forms a homodimer to recognize the major groove of A-form dsRNA in a length-independent mode by its conserved concave surface formed by dimeric anti-parallel a-helices, dsRNA is anchored by a pair of invariable arginines （Arg38） from both monomers by extensive hydrogen bonds. In accordance with the structural observation, isothermal titration calorimetry assay shows that the unique Arg38-Arg38 pair and two Arg35-Arg46 pairs are crucial for dsRNA binding, and that Ser42 and Thr49 are also important for dsRNA binding. Agrobacterium co-infiltration assay further supports that the unique Arg38 pair plays important roles in dsRNA binding in vivo.

Predator perception of detritus and eggsac decorations spun by orb-web spiders Cyclosa octotuberculata:Do they function to camouflage the spiders?

Camouflage is one of the most widespread and powerful strategies that animals use to make detection/recognition more difficult. Many orb-web spiders of the genus Cyclosa add prey remains, plant debris, moults, and/or eggsacs to their webs called web decorations. Web decorations resembling spider body colour pattern have been considered to camouflage the spider from predators. While this camouflage is obvious from a human＇s perspective, it has rarely been investigated from a predator＇s perspective. In this study, we tested the visibility of web decorations by calculating chromatic and achromatic contrasts of detritus and eggsae decorations built by Cyclosa octotubereulata, against four different backgrounds viewed by both bird （e.g., blue tits） and hymenopteran （e.g. wasps） predators. We showed that both juvenile and adult spiders on webs with detritus or egg-sac deco- rations were undetectable by both hymenopteran and bird predators over short and long distances. Our results thus suggest that decorating webs with detritus or eggsacs by C octotuberculata may camouflage the spiders from both hymenopteran and bird predators in their common habitats [Current Zoology 56 （3）： 379-387, 2010].

A New Problem with Cross-Species Amplification of Microsatellites: Generation of Non-Homologous Products

Microsatellites have been widely used in studies on population genetics, ecology and evolutionary biology. However, microsatellites are not always available for the species to be studied and their isolation could be time-consuming. In order to save time and effort researchers often rely on cross-species amplification. We revealed a new problem of microsatellite cross-species amplification in addition to size homoplasy by analyzing the sequences of electromorphs from seven catfish species belonging to three different families （Clariidae, Heteropneustidae and Pimelodidae）. A total of 50 different electromorphs were amplified from the seven catfish species by using primers for 4 microsatellite loci isolated from the species Clarias batrachus. Two hundred and forty PCR-products representing all 50 electromorphs were sequenced and analyzed. Primers for two loci amplified specific products from orthologous loci in all species tested, whereas primers for the other two loci produced specific and polymorphic bands from some non-orthologous loci, even in closely related non-source species. Size homoplasy within the source species was not obvious, whereas extensive size homoplasy across species were detected at three loci, but not at the fourth one. These data suggest that amplification of products from non-orthologous loci and appearance of size homoplasy by cross-amplification are locus dependent, and do not reflect phylogenetic relationship. Amplification of non-orthologous loci and appearance of size homoplasy will lead to obvious complications in phylogenetie interference, population genetic and evolutionary studies. Therefore, we propose that sequence analysis of cross-amplification products should be conducted prior to application of cross-species amplification of microsatellites.

Marker-Assisted Breeding of Thermo-Sensitive Genic Male Sterile Line 1892S for Disease Resistance and Submergence Tolerance

Rice line 1892S is an elite thermo-sensitive genic male sterile(TGMS)line for two-line hybrid rice production.However,1892S is susceptible to rice blast,bacterial blight and submergence.Here we reported the introduction of blast resistance(R)gene Pi9,bacterial blight R gene Xa21 and submergence tolerance gene Sub1A into 1892S genetic background through backcrossing and marker-assisted selection.The improved TGMS line 31892S and its hybrids conferred disease resistance to rice blast and bacterial blight,and showed submergence tolerance for over 14 d without significant loss of viability.The sterility-fertility conversion of 31892S was similar to that of 1892S.31892S and its derived hybrid rice had similar agronomic traits and grain quality with 1892S and the control hybrid rice,respectively.The newly developed 31892S provided an improved TGMS line for two-line hybrid rice production with disease resistance to rice blast and bacterial blight,and submergence tolerance with no yield penalty or change in grain quality.

Whole-genome resequencing infers genomic basis of giant phenotype in Siamese fighting fish(Betta splendens)

Understanding the genetic basis of phenotypes is of importance in evolutionary biology and for genetic improvement of economically valuable animals.The giant phenotype of the fighting fish,Betta splendens,provides a unique opportunity to explore the genetic architecture of overgrowth in body size.As such,we re-sequenced and analyzed the genomes of 54 fighting fish.Genome-wide FST and selective sweep analyses using 3582429 DNA variants revealed three genomic regions at chr1,chr9,and chr11 that were associated with the giant phenotype.With a total length of~3.5 Mb,these regions showed high divergence between the giant and non-giant bettas.In contrast,no signature of selection was detected in the wild-type fish.Transcriptome analysis of brain and muscle samples from giant and normal bettas identified 14 candidate genes that were likely responsible for the giant phenotype.Overall,our data provide novel insights into the genetic basis of body size variation.The genome sequences,transcriptome sequences,DNA sequence variants,and candidate genes for body size provide valuable resources for further biological and evolutionary studies,as well as for rapid improvement in growth-related traits.

Identification of antimalarial targets of chloroquine by a combined deconvolution strategy of ABPP and MS-CETSA

Background: Malaria is a devastating infectious disease that disproportionally threatens hundreds of millions of people in developing countries. In the history of anti-malaria campaign, chloroquine(CQ) has played an indispensable role, however, its mechanism of action(MoA) is not fully understood.Methods: We used the principle of photo-affinity labeling and click chemistry-based functionalization in the design of a CQ probe and developed a combined deconvolution strategy of activity-based protein profiling(ABPP) and mass spectrometry-coupled cellular thermal shift assay(MS-CETSA) that identified the protein targets of CQ in an unbiased manner in this study. The interactions between CQ and these identified potential protein hits were confirmed by biophysical and enzymatic assays.Results: We developed a novel clickable, photo-affinity chloroquine analog probe(CQP) which retains the antimalarial activity in the nanomole range, and identified a total of 40 proteins that specifically interacted and photocrosslinked with CQP which was inhibited in the presence of excess CQ. Using MS-CETSA, we identified 83 candidate interacting proteins out of a total of 3375 measured parasite proteins. At the same time, we identified 8 proteins as the most potential hits which were commonly identified by both methods.Conclusions: We found that CQ could disrupt glycolysis and energy metabolism of malarial parasites through direct binding with some of the key enzymes, a new mechanism that is different from its well-known inhibitory effect of hemozoin formation. This is the first report of identifying CQ antimalarial targets by a parallel usage of labeled(ABPP)and label-free(MS-CETSA) methods.

Enrichment of novel Tau isoform with altered biochemical properties in Alzheimer's disease

Aberrant splicing in sporadic Alzheimer’s disease:Alzheimer’s disease (AD) is a progressive neurodegenerative disorder cha racterized by the presence of extracellular amyloid-β plaques and Tau-containing intracellular neurofib rilla ry tangles (Knopman et al.,2021).Cognitive decline in AD due to neuronal and synaptic loss is caused by the complex interplay between pathological amyloid-β and Tau species with the impaired innate clearance pathways.There are two types of AD based on disease aetiology (Knopman et al.,2021).

Mechanistic engineering of celastrol liposomes induces ferroptosis and apoptosis by directly targeting VDAC2 in hepatocellular carcinoma

Hepatocellular carcinoma(HCC)is one of most common and deadliest malignancies.Celastrol(Cel),a natural product derived from the Tripterygium wilfordii plant,has been extensively researched for its potential effectiveness in fighting cancer.However,its clinical application has been hindered by the unclear mechanism of action.Here,we used chemical proteomics to identify the direct targets of Cel and enhanced its targetability and antitumor capacity by developing a Cel-based liposomes in HCC.We demonstrated that Cel selectively targets the voltage-dependent anion channel 2(VDAC2).Cel directly binds to the cysteine residues of VDAC2,and induces cytochrome C release via dysregulating VDAC2-mediated mitochondrial permeability transition pore(mPTP)function.We further found that Cel induces ROS-mediated ferroptosis and apoptosis in HCC cells.Moreover,coencapsulation of Cel into alkyl glucoside-modified liposomes(AGCL)improved its antitumor efficacy and minimized its side effects.AGCL has been shown to effectively suppress the proliferation of tumor cells.In a xenograft nude mice experiment,AGCL significantly inhibited tumor growth and promoted apoptosis.Our findings reveal that Cel directly targets VDAC2 to induce mitochondria-dependent cell death,while the Cel liposomes enhance its targetability and reduces side effects.Overall,Cel shows promise as a therapeutic agent for HCC.

A highly efficient protein corona-based proteomic analysis strategy for the discovery of pharmacodynamic biomarkers

The composition of serum is extremely complex,which complicates the discovery of new pharmacodynamic biomarkers via serum proteome for disease prediction and diagnosis.Recently,nanoparticles have been reported to efficiently reduce the proportion of high-abundance proteins and enrich lowabundance proteins in serum.Here,we synthesized a silica-coated iron oxide nanoparticle and developed a highly efficient and reproducible protein corona(PC)-based proteomic analysis strategy to improve the range of serum proteomic analysis.We identified 1,070 proteins with a median coefficient of variation of 12.56%using PC-based proteomic analysis,which was twice the number of proteins identified by direct digestion.There were also more biological processes enriched with these proteins.We applied this strategy to identify more pharmacodynamic biomarkers on collagen-induced arthritis(CIA)rat model treated with methotrexate(MTX).The bioinformatic results indicated that 485 differentially expressed proteins(DEPs)were found in CIA rats,of which 323 DEPs recovered to near normal levels after treatment with MTX.This strategy can not only help enhance our understanding of the mechanisms of disease and drug action through serum proteomics studies,but also provide more pharmacodynamic biomarkers for disease prediction,diagnosis,and treatment.

A New Species of Euphlyctis (Amphibia, Anura, Dicroglossidae) from the West Coastal Plains of India

The genus Euphlyctis is widely distributed across Southwestern Arabian Peninsula into parts of Southeast Asia. Five of the seven known Euphlyctis species are found within the Indian subcontinent. Here, we describe a new species, Euphlyctis karaavali sp. nov. from South-west coast of India, which was discovered during surveys engaging citizens. This species was identified to be distinct based on molecular and morphological evidence. We provide a detailed description of this species along with its call description and compare it with closest congeners. Previous studies in the region had identified this species as E. hexadactylus but suggested the possibility of it being cryptic. Genetically E. karaavali sp. nov. is distinct from E. hexadactylus with a genetic divergence of 9.2% （12S and 16S） and shows a high divergence with E. kalasgramensis and E. ehrenbergii （13.04% each）. Our findings are discussed in the context of cryptic species discovery, citizen engagement in scientific progress and conservation measures while suggesting future directions.

Phylogeography and diversification of Oriental weaverbirds(Ploceus spp.):A gradual increase of eurytopy

Weaverbirds are a speciose group of colorful passerines inhabiting the Old World Tropics.Nevertheless,the Oriental weaverbirds(Ploceus spp.),widespread across southern Asia,are much less diverse and restricted to a few ecological niches compared to their African counterpart.To investigate their phylogeography,we retrieved 101 samples of Baya Weaver(P.philippinus),Streaked Weaver(P.manyar),Black-Throated Weaver(P.benghalensis)and Asian Golden Weaver(P.hypoxanthus)along with GenBank sequences of Finn's Weaver(P.megarhynchus).We reconstructed the first molecular phylogeny based on a dataset consisting of both mitochondrial and nuclear genes,dating the most recent common ancestor of Oriental Ploceus to~11 mya.Subsequent speciation appears to have been a combination of divergence within the Indian subcontinent and dispersal across a barrier situated between the Indian subcontinent and the Indochinese region,which provided habitats with a varying degree of isolations and ultimately promoted divergences in allopatry.Two descendants of the earliest nodes,P.megarhynchus and P.hypoxanthus,are both rare and local,often found near large river systems,which perhaps reflects niche conservatism and a lack of adaptive potential.The three smaller species are all widespread,common and less habitat specific.The most recent divergence,between western and eastern P.philippinus populations,is supported by both phylogenetic and morphological evidence,pointing toward limited gene flow between them.However,a zone of intergradation may exist in Myanmar and Brahmaputra flood plains,thus preventing a recommendation for species level recognition without further study.

Informatics-based prediction of molecular networks targeted by active ingredients in Danshen (Salvia miltiorrhiza)

Salvia miltiorrhiza (Chinese, Danshen) is one of the most famous traditional herbs, and has been used to treat cardiovascular disease. Despite the wide application of Danshen in China, the mechanisms of its bioactive components are poorly understood. The present study used bioinformatics to identify possible mechanisms by which Danshen treats cardiovascular disease. Possible human protein targets of Danshen were identified in the PubChem database, possible human gene targets of cardiovascular disease were identified in the NCBI database, and then both sets of targets were analyzed using Ingenuity Pathway Analysis to predict molecular networks affected by Danshen in cardiovascular disease. The results suggest that signaling proteins affected by Danshen in cardiovascular disease, which include FASN, PAFAH1B2, PLA2G7, PAFAH1B3 and IL1B, are involved primarily in LXR/RXR activation, atherosclerosis signaling, hepatic fibrosis/hepatic stellate cell activation, acute phase response signaling. The main networks affected by Danshen are predicted to involve in cellular movement, immune cell trafficking, hematological system development and function;DNA replication, recombination, and repair, cancer, hematological disease;cardiovascular disease, organismal injury and abnormalities, tissue morphology.These results identify several specific proteins and pathways that may be affected by Danshen in cardiovascular disease, and they illustrate the power of integrative bioinformatics and chemical fragment analysis for focusing mechanistic studies.

Apolipoprotein E elicits targetdirected miRNA degradation to maintain neuronal integrity

Apolipoprotein E has diverse functions in neurons:Apolipoprotein E(ApoE)is a glycoprotein that primarily regulates lipid metabolism and transport in the central nervous system.There are three predominant human ApoE protein isoforms with cysteine and arginine substitutions at amino acid positions 112 and 158 that impact their lipidation and related functions(Flowers and Rebeck,2020).ApoE2 is characterized by Cys112 and Cys158,ApoE3 by Cys112 and Arg158,whereas ApoE4 contains Arg112 and Arg158.

Oviposition Site Selection in the Malayan Giant Frog (Limnonectes blythii) in Singapore: Conservation Implications

Amphibians require specific habitats for breeding and loss or degradation of such habitats can negatively affect reproductive success. Oviposition site selection within a habitat is also important as site quality is linked to larval survivorship and metamorphic success. We investigated oviposition site preferences of the stream-breeding frog Limnonectes blythii in Singapore through surveys and habitat measurements of breeding and non-breeding sites（N = 30 and 32, respectively）. The study species L. blythii is classified as Near Threatened（NT） in the IUCN red list and is associated with medium sized forest streams. L. blythii appeared to prefer streams with higher water p H and shallower water depths for oviposition. Our findings have implications in conservation management as it provides the baseline for habitat restoration for creation of new and for preserving existing breeding habitat of L. blythii.

Simvastatin enhanced growth and altered testis transcriptome profiles of male tilapias

Simvastatin(SIM),a commonly prescribed drug for lowering serum-lipid,has been detected in many aquatic environments.Exposure to high concentrations of SIM in rats and aquatic organisms resulted in toxicity to hepatocytes and negative effects on development.However,there is a paucity of studies on the effects of long-term exposure to low concentrations of SIM on aquaculture species.This study aimed to analyze the effects of environmentally relevant concentrations(0.1μg/L and 1μg/L)of SIM exposure for two months on developing Mozambique tilapias.Surprisingly,the growth of male tilapias was enhanced after a 2-month SIM exposure.The analysis of testis histology revealed that after the SIM exposure,the development of the testis was delayed,and sperm production was reduced.Sequencing of testis transcriptomes showed that the exposure to SIM altered the expression of many genes related to the development of testes and spermatogenesis.These data suggest that a 2-month exposure to environmentally relevant concentrations of increases the growth of male tilapias by inhibiting sexual development of males.

Symmetry quantification and segmentation in STEM imaging through Zernike moments

We present a method using Zernike moments for quantifying rotational and reflectional symmetries in scanning transmission electron microscopy(STEM)images,aimed at improving structural analysis of materials at the atomic scale.This technique is effective against common imaging noises and is potentially suited for low-dose imaging and identifying quantum defects.We showcase its utility in the unsupervised segmentation of polytypes in a twisted bilayer TaS_(2),enabling accurate differentiation of structural phases and monitoring transitions caused by electron beam effects.This approach enhances the analysis of structural variations in crystalline materials,marking a notable advancement in the characterization of structures in materials science.