Insect protein digestion improves purity of Steinernema carpocapsae in vitro culture and reduces culture period

Insect protein, used for in vitro culture media for entomopathogenic nematode, produces nematodes of high quality. However, the time-consuming culture and poor purity of nematodes hinder the commercial application of insect protein media. We show that hydrolyzed insect protein improves nematode purity in in vitro culture. The results revealed that nematode purity was increased by more than 90 %, and the culture period was reduced by 6 days. Estimated economic efficiency of using hydrolyzed insect protein medium was increased by 44.25 % over that obtained with non-hydrolyzed insect medium.     

Virus-like particles produced in Saccharomyces cerevisiae elicit protective immunity against Coxsackievirus A16 in mice

Hand, foot, and mouth disease (HFMD) has caused significant morbidity and mortality in the Asia-Pacific regions, particularly in infants and young children. Coxsackievirus A16 (CA16) represents one of the major causative agents for HFMD, and the development of a safe and effective vaccine preventing CA16 infections has become a public health priority. In this study, we have developed a yeast system for the production of virus-like particles (VLPs) for CA16 by co-expressing P1 and 3CD of CA16 in Saccharomyces cerevisiae. These VLPs exhibit similarity in both protein composition and morphology as empty particles from CA16-infected cells. Immunization with CA16 VLPs in mice potently induced CA16-specific IgG and neutralization antibodies in a dose-dependent manner. IgG subclass isotyping revealed that IgG1 and lgG2b were dominantly induced by VLPs. Meanwhile, cytokine profiling demonstrated that immunization with VLPs significantly induced the secretion of IFN-γ, indicating potent cellular immune response. Furthermore, in vivo challenge experiments showed that passive immunization with anti-VLPs sera conferred full protection against lethal CA16 challenge in neonate mice. Taken together, our data demonstrated that VLPs produced in yeast might have the potential to be further developed as a vaccine candidate against HFMD.     

Optogenetic reporters

The discovery of naturally evolved fluorescent proteins and their subsequent tuning by protein engineering provided the basis for a large family of genetically encoded biosensors that report a variety of physicochemical processes occurring in living tissue. These optogenetic reporters are powerful tools for live‐cell microscopy and quantitative analysis at the subcellular level. In this review, we present an overview of the transduction mechanisms that have been exploited for engineering these genetically encoded reporters. Finally, we discuss current and future efforts towards the combined use of various optogenetic actuators and reporters for simultaneously controlling and imaging the physiology of cells and tissues.     

异育银鲫GABAB受体1亚基 cDNA部分序列的克隆及组织表达分析

为了确定γ-氨基丁酸B受体（gamma-aminobutyric acid B receptor,GABABR）基因在异育银鲫（Carassius auratus gibelio）不同组织中的表达,本实验分别对异育银鲫不同组织中GABABR1基因进行RT-PCR扩增,并进行了克隆和测序,在与GenBank基因库中已知GABABR1序列进行同源性比对的基础上采用邻接法构建系统发育树,并进一步分析其在异育银鲫不同组织内的表达水平。结果：经克隆获得异育银鲫GABABR1基因CDS区序列383bp,编码127个氨基酸。荧光定量PCR结果显示GABABR1基因在异育银鲫脑、肝、肾、心、肠、鳔、鳃、肌、鳍、脾、卵巢、精巢组织中均有表达,且在不同组织中的表达水平由高到低依次是：脑>尾鳍>精巢>心、肠、鳔> 卵巢、脾、鳃、肌>肝、肾。本研究证实了GABABR1基因在异育银鲫各组织中的表达的广泛性,且有明显的组织特异性。     

The Drosophila putative histone acetyltransferase Enok maintains female germline stem cells through regulating Bruno and the niche

Maintenance of adult stem cells is largely dependent on the balance between their self-renewal and differentiation. The Drosophila ovarian germline stem cells (GSCs) provide a powerful in vivo system for studying stem cell fate regulation. It has been shown that maintaining the GSC population involves both genetic and epigenetic mechanisms. Although the role of epigenetic regulation in this process is evident, the underlying mechanisms remain to be further explored. In this study, we find that Enoki mushroom (Enok), a Drosophila putative MYST family histone acetyltransferase controls GSC maintenance in the ovary at multiple levels. Removal or knockdown of Enok in the germline causes a GSC maintenance defect. Further studies show that the cell-autonomous role of Enok in maintaining GSCs is not dependent on the BMP/Bam pathway. Interestingly, molecular studies reveal an ectopic expression of Bruno, an RNA binding protein, in the GSCs and their differentiating daughter cells elicited by the germline Enok deficiency. Misexpression of Bruno in GSCs and their immediate descendants results in a GSC loss that can be exacerbated by incorporating one copy of enok mutant allele. These data suggest a role for Bruno in Enok-controlled GSC maintenance. In addition, we observe that Enok is required for maintaining GSCs non-autonomously. Compromised expression of enok in the niche cells impairs the niche maintenance and BMP signal output, thereby causing defective GSC maintenance. This is the first demonstration that the niche size control requires an epigenetic mechanism. Taken together, studies in this paper provide new insights into the GSC fate regulation.     

The Role of Semidisorder in Temperature Adaptation of Bacterial FlgM Proteins

Probabilities of disorder for FlgM proteins of 39 species whose optimal growth temperature ranges from 273 K (0°C) to 368 K (95°C) were predicted by a newly developed method called Sequence-based Prediction with Integrated NEural networks for Disorder (SPINE-D). We showed that the temperature-dependent behavior of FlgM proteins could be separated into two subgroups according to their sequence lengths. Only shorter sequences evolved to adapt to high temperatures (>318 K or 45°C). Their ability to adapt to high temperatures was achieved through a transition from a fully disordered state with little secondary structure to a semidisordered state with high predicted helical probability at the N-terminal region. The predicted results are consistent with available experimental data. An analysis of all orthologous protein families in 39 species suggests that such a transition from a fully disordered state to semidisordered and/or ordered states is one of the strategies employed by nature for adaptation to high temperatures.     

An Embryonic Myosin Isoform Enables Stretch Activation and Cyclical Power in Drosophila Jump Muscle

The mechanism behind stretch activation (SA), a mechanical property that increases muscle force and oscillatory power generation, is not known. We used Drosophila transgenic techniques and our new muscle preparation, the jump muscle, to determine if myosin heavy chain isoforms influence the magnitude and rate of SA force generation. We found that Drosophila jump muscles show very low SA force and cannot produce positive power under oscillatory conditions at pCa 5.0. However, we transformed the jump muscle to be moderately stretch-activatable by replacing its myosin isoform with an embryonic isoform (EMB). Expressing EMB, jump muscle SA force increased by 163% and it generated net positive power. The rate of SA force development decreased by 58% with EMB expression. Power generation is Pi dependent as >4 mM Pi was required for positive power from EMB. Pi increased EMB SA force, but not wild-type SA force. Our data suggest that when muscle expressing EMB is stretched, EMB is more easily driven backward to a weakly bound state than wild-type jump muscle. This increases the number of myosin heads available to rapidly bind to actin and contribute to SA force generation. We conclude that myosin heavy chain isoforms influence both SA kinetics and SA force, which can determine if a muscle is capable of generating oscillatory power at a fixed calcium concentration.