Smarter birds, smaller eggs, and less parental care time

DEAR EDITOR,Natural selection favors encephalization(i.e., enlargement of relative brain size) not only because it ultimately enhances the survival of organisms but also because it does not impair reproductive success. However, little is known regarding how encephalization does not impact the reproductive success of organisms. Here, by analyzing a dataset of more than 1 000 modern bird species.

Impacts on Bats by a Supertyphoon vs.Ordinary Typhoons along a Habitat Urbanization Gradient

Two major human-caused threats to ecosystems are habitat modification and the increasing frequency and intensity of extreme weather events.To study the combined effect of these threats,the authors used acoustic monitoring of bats along a habitat modification gradient on the island of Okinawa,Japan.During the observation period,the island experienced numerous typhoons and one supertyphoon.Native bat species remained active even at high wind speeds(up to 30 m/s in some cases).Milder typhoons had no observable effect on bat populations,with activity levels fully recovering within a few hours or days.The super typhoon also did not seem to affect bats in fully or partially forested habitats but caused their local disappearance at the urban site,which they have not re-colonized three years after the event.Notably,bats that disappeared at the urban site were species roosting in well-protected places such as caves and concrete structures.In all cases,the biomass of small flying insects and the acoustic activity of insects recovered within days after extreme weather events.Thus,the striking difference between habitats in supertyphoon effects on bats cannot be explained by the super typhoon directly killing bats,destroying their roosting sites,or decreasing the abundance of their prey.The results underscore the importance of preserving natural habitats in areas particularly affected by changing climate and show that the survival of species and ecosystems during the numerous episodes of climate change in the Earth’s history does not necessarily mean their ability to survive the accelerating climate change of our time.

Mechanically induced Ca^(2+) oscillations in osteocytes release extracellular vesicles and enhance bone formation

The vast osteocytic network is believed to orchestrate bone metabolic activity in response to mechanical stimuli through production of sclerostin, RANKL, and osteoprotegerin(OPG). However, the mechanisms of osteocyte mechanotransduction remain poorly understood. We've previously shown that osteocyte mechanosensitivity is encoded through unique intracellular calcium (Ca^(2+) ) dynamics. Here, by simultaneously monitoring Ca^(2+) and actin dynamics in single cells exposed to fluid shear flow, we detected actin network contractions immediately upon onset of flow-induced Ca^(2+) transients, which were facilitated by smooth muscle myosin and further confirmed in native osteocytes ex vivo. Actomyosin contractions have been linked to the secretion of extracellular vesicles(EVs), and our studies demonstrate that mechanical stimulation upregulates EV production in osteocytes through immunostaining for the secretory vesicle marker Lysosomal-associated membrane protein 1(LAMP1) and quantifying EV release in conditioned medium, both of which are blunted when Ca^(2+) signaling was inhibited by neomycin. Axial tibia compression was used to induce anabolic bone formation responses in mice, revealing upregulated LAMP1 and expected downregulation of sclerostin in vivo. This load-related increase in LAMP1 expression was inhibited in neomycin-injected mice compared to vehicle.Micro-computed tomography revealed significant load-related increases in both trabecular bone volume fraction and cortical thickness after two weeks of loading, which were blunted by neomycin treatment. In summary, we found mechanical stimulation of osteocytes activates Ca^(2+) -dependent contractions and enhances the production and release of EVs containing bone regulatory proteins. Further, blocking Ca^(2+) signaling significantly attenuates adaptation to mechanical loading in vivo, suggesting a critical role for Ca^(2+) -mediated signaling in bone adaptation.

Predicting suitable habitat of an invasive weed Parthenium hysterophorus under future climate scenarios in Chitwan Annapurna Landscape,Nepal

Chitwan-Annapuma Landscape(CHAL)in central Nepal is known for its rich biodiversity and the landscape is expected to provide corridors for species range shift in response to climate change.Environmental assessments have identified biological invasions and other anthropogenic activities as major threats to the biodiversity in the CHAL.One of the rapidly spreading Invasive Alien Plant species(IAPs)in the CHAL is Parthenium hysterophorus L.,a neotropical invasive weed of global significance.This study aimed to investigate the current and future projected suitable habitat of P.hysterophorus in the CHAL using MaxEnt modelling in three'Representative Concentration Pathways'(RCPs 2.6,4.5 and 8.5)corresponding to different greenhouse gases emissiontrajectories for the year 2050 and 2070.A total of 288species occurrence points,six bioclimatic variablesmean diurnal range,isothermality,annual precipitation,precipitation of driest month,precipitation seasonality,precipitation of driest quarter and two topographic variables(aspect and slope)were selected for MaxEnt modelling.Potential range shift in terms of increase or decline in the suitable habitat areas under the projected scenarios were calculated.Slope and annual precipitation were the most important variables that explained the current distribution of P.hysterophorus.Twenty percent of the total area of CHAL was predicted to be suitable habitat for the growth of P.hysterophorus in the current climatic condition.Highest gain in the suitable habitat of this noxious weed was found under RCP 4.5 scenario in 2050 and 2070.whereas there will be a loss in thesuitable habitat under RCP 8.5 scenario in 2050 and2070.Out of four physiographic regions present in CHAL,three regions-Siwalik,Middle Mountain and High Mountain have suitable habitat for P.hysterophorus under current climatic condition.The mountainous region is likely to be affected more than the Siwalik region by further spread of P.fhysteropfhorus in the future under low(RCP 2.6)to medium(RCP 4.5)emission scenarios.The suitable habitat for this weed is likely to increase in the protected areas of mountain regions(Langtang National Park,Annapurna Conservation Area and Manaslu Conservation Area)in the future.The results have revealed a risk of spreading P.hysterophorus from present localities to non-invaded areas in the current and future climatic condition.Such risk needs to be considered by decision makers and resource managers while planning for effective management of this weed to reduce its ecological and economic impacts in the CHAL.

A mathematical Model for Inter-Cellular Inductive

In vertebrate limb, a group of specialized epithelial cells called Apical Ectodermal Ridge (AER) form at the boundary of dorsal and ventral limb ectoderm. Recent experiments suggest that AER forms at the boundary of Fringe expressing and Fringe non-expressing cells by a specific type of receptor-ligand interaction called as inductive signaling, involving the transmembrane proteins Notch, Serrate and Delta. Experiments conducted on Drosophila wing disc have shown that Fringe inhibits the binding ability of Serrate ligand to Notch and enhances that of Delta to Notch. Although several of the signaling elements have been identified experimentally, it remains unclear how the inter-cellular interactions can give rise to such a boundary of specialized cells. Here we present an ordinary differential equation (ODE) model involving Delta→Notch and Serrate→Notch interactions between juxtaposed Fringe expressing and Fringe nonexpressing cells. When simulated in a compartmentalized set up, this model gives rise to high Notch levels at the boundary of Fringe expressing and Fringe non-expressing cells.

周年生物钟:赋予动物预知季节的能力

Seasonal changes in climate and animal behaviors have been depicted in Chinese literature since ancient times,such as the classical poem"HuìChóng Ch-un Jiang Wǎn Jǐng"by Su Shi.We now know that the intricate interplays among the Sun,the Earth,and the Moon shape periodic environmental changes.

基于DNA技术的非对称加密与签名方法

结合现代基因工程技术和密码学技术设计了一个非对称加密与签名系统DNA-PKC,这是在生物密码研究领域的初步探索.类似于传统的公钥密码,DNA-PKC的密钥由加密钥和解密钥组成,加密者之间互相不能解密,只有解密钥的拥有者才能解密所有密文.不同于传统的公钥密码,DNA-PKC的密钥与密文均为生物分子实物,在应用协议等方面具有不同的要求.在安全性方面,DNA-PKC主要依赖于生物学问题而不是传统的计算困难问题,因而对未来的量子计算机的攻击免疫.

Climate and land-use interactively shape butterfly diversity in tropical rainforest and savanna ecosystems of southwestern China

Human-induced habitat conversion and degradation,along with accelerating climatic change,have resulted in considerable global biodiversity loss.Nevertheless,how local ecological assemblages respond to the interplay between climate and land-use change remains poorly understood.Here,we examined the effects of climate and land-use interactions on butterfly diversity in different ecosystems of southwestern China.Specifically,we investigated variation in the alpha and beta diversities of butterflies in different landscapes along human-modified and climate gradients.We found that increasing land-use intensity not only caused a dramatic decrease in butterfly alpha diversity but also significantly simplified butterfly species composition in tropical rainforest and savanna ecosystems.These findings suggest that habitat modification by agricultural activities increases the importance of deterministic processes and leads to biotic homogenization.The land-use intensity model best explained species richness variation in the tropical rainforest,whereas the climate and land-use intensity interaction model best explained species richness variation in the savanna.These results indicate that climate modulates the effects of land-use intensity on butterfly alpha diversity in the savanna ecosystem.We also found that the response of species composition to climate varied between sites:specifically,species composition was strongly correlated with climatic distance in the tropical rainforest but not in the savanna.Taken together,our long-term butterfly monitoring data reveal that interactions between human-modified habitat change and climate change have shaped butterfly diversity in tropical rainforest and savanna.These findings also have important implications for biodiversity conservation under the current era of rapid human-induced habitat loss and climate change.

The Human Genome Project: the Beginning of the Beginning

The Human Genome Project(HGP)is a historical and landmark scientific project.In spite of initial controversy it has become a bedrock foundation for much progress in biological science and human health.After the Human Genome Project was completed in the early 2000s,next generation sequencing technologies were developed and that has revolutionized genomics.Here is a brief account of the May 1985 meeting at University of California Santa Cruz.Historical accounts often begin with a the Department of Energy(DOE)meeting in Santa Fe in March 1986 and neglect including the Santa Cruz meeting[1],although sometimes it is discussed[2].

Integrated tool for microsatellite isolation and validation from the reference genome and their application in the study of breeding turnover in an endangered avian population

Accurate individual identification is required to estimate survival rates in avian populations.For endangered species,non-invasive methods of obtaining individual identification,such as using molted feathers as a source of DNA for microsatellite markers,are preferred because of less disturbance,easy sample preparation and high efficiency.With the availability of many avian genomes,a few pipelines isolating genome-wide microsatellites have been published,but it is still a challenge to isolate microsatellites from the reference genome efficiently.Here,we have developed an integrated tool comprising a bioinformatic pipeline and experimental procedures for microsatellite isolation and validation based on the reference genome.We have identified over 95000 microsatellite loci and established a system comprising 10 highly polymorphic markers(PIC value:0.49–0.93,mean:0.79)for an endangered species,saker falcon(Falco cherrug).These markers(except 1)were successfully amplified in 126 molted feathers,exhibiting high amplification success rates(83.9–99.7%),high quality index(0.90–0.97)and low allelic dropout rates(1–9.5%).To further assess the efficiency of this marker system in a population study,we identified individual sakers using these molted feathers(adult)and 146 plucked feathers(offspring).The use of parent and offspring samples enabled us to infer the genotype of missing samples(N=28),and all adult genotypes were used to ascertain that breeding turnover is a useful proxy for survival estimation in sakers.Our study presents a cost-effective tool for microsatellite isolation based on publicly available reference genomes and demonstrates the power of this tool in estimating key parameters of avian population dynamics.

Deciphering the Stigmatic Transcriptional Landscape of Compatible and Self-Incompatible Pollinations in Brassica napus Reveals a Rapid Stigma Senescence Response Following Compatible Pollination

Dear Editor, Self-incompatibility （SI） is a genetic mechanism through which flowering plants prevent self-pollination to ensure out- crossing and genetic diversity. In Brassica sp., this mechanism is controlled by the self-incompatibility （S） locus, in which, the stigmatic ＇S-locus receptor kinase （SRK）＇ recognizes the ＇S-locus cysteine rich protein （SCR）＇ from the self-pollen to elicit an active rejection response. This results in blocking of compatibil- ity factors from being delivered to the site of pollen attachment leading to self-pollen rejection （Chapman and Goring, 2010）. In contrast, following recognition of compatible signals from the cross-pollen or compatible pollen （CP）, the stigma releases its resources such as water and nutrients to the dry pollen so that the pollen tube can germinate and penetrate the stigmatic cuticle leading to successful fertilization. Thus, an incompatible or self-pollen is fully capable of eliciting a compatible response, but is actively rejected before compatible responses can occur.

A theoretical study of the mechanism of the nucleotidyl transfer reaction catalyzed by yeast RNA polymerase Ⅱ

The mechanism of the nucleotidyl transfer reaction catalyzed by yeast RNA polymerase II has been investigated using molecular mechanics and quantum mechanics methods.Molecular dynamics(MD) simulations were carried out using the TIP3 water model and generalized solvent boundary potential(GSBP) by CHARMM based on the X-ray crystal structure.Two models of the ternary elongation complex were constructed based on CHARMM MD calculations.All the species including reactants,transition states,intermediates,and products were optimized using the DFT-PBE method coupled with the basis set DZVP and the auxiliary basis set GEN-A2.Three pathways were explored using the DFT method.The most favorable reaction pathway involves indirect proton migration from the RNA primer 3'-OH to the oxygen atom of-phosphate via a solvent water molecule,proton rotation from the oxygen atom of-phosphate to the-phosphate side,the RNA primer 3'-O nucleophilic attack on the-phosphorus atom,and P-O bond breakage.The corresponding reaction potential profile was obtained.The rate limiting step,with a barrier height of 21.5 kcal/mol,is the RNA primer 3'-O nucleophilic attack,rather than the commonly considered proton transfer process.A high-resolution crystal structure including crystallographic water molecules is required for further studies.