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Spring viremia of carp virus (SVCV) causes devastating losses in aquaculture. Coumarin has an advantageous structure for the design of novel antiviral agents with high affinity and specificity. In this study, we evaluated a hydroxycoumarin medicine, i.e., 7-(6-benzimidazole) coumarin (C10), regarding its anti-SVCV effects in vitro and in vivo. Results showed that up to 12.5 mg/L C10 significantly inhibited SVCV replication in the epithelioma papulosum cyprini (EPC) cell line, with a maximum inhibitory rate of >97%. Furthermore, C10 significantly reduced cell death and relieved cellular morphological damage in SVCV-infected cells. Decreased mitochondrial membrane potential (ΔΨm) also suggested that C10 not only protected mitochondria, but also reduced apoptosis in SVCV-infected cells. For in vivo studies, intraperitoneal injection of C10 resulted in an anti-SVCV effect and substantially enhanced the survival rate of virus-infected zebrafish. Furthermore, C10 significantly enhanced antioxidant enzyme activities and decreased reactive oxygen species (ROS) to maintain antioxidant-oxidant balance within the host, thereby contributing to inhibition of SVCV replication. The up-regulation of six interferon (IFN)-related genes also demonstrated that C10 indirectly activated IFNs for the clearance of SVCV in zebrafish. This was beneficial for the continuous maintenance of antiviral effects because of the low viral loads in fish. Thus, C10 is suggested as a therapeutic agent with great potential against SVCV infection in aquaculture.
Exosomes are small vesicles secreted by all cell types in the brain and play a role in cell-cell communication through the transfer of cargo or encapsulation. Exosomes in the brain have considerable impact on neuronal development, activation, and regeneration. In addition, exosomes are reported to be involved in the onset and propagation of various neurodegenerative diseases. In this review, we discuss the content of exosomes derived from major cell types in the brain, and their function under physiological and pathological conditions.
Understanding the genetic mechanisms underlying particular adaptations/phenotypes of organisms is one of the core issues of evolutionary biology. The use of genomic data has greatly advanced our understandings on this issue, as well as other aspects of evolutionary biology, including molecular adaptation, speciation, and even conservation of endangered species. Despite the well-recognized advantages, usages of genomic data are still limited to non-mammal vertebrate groups, partly due to the difficulties in assembling large or highly heterozygous genomes. Although this is particularly the case for amphibians, nonetheless, several comparative and population genomic analyses have shed lights into the speciation and adaptation processes of amphibians in a complex landscape, giving a promising hope for a wider application of genomics in the previously believed challenging groups of organisms. At the same time, these pioneer studies also allow us to realize numerous challenges in studying the molecular adaptations and/or phenotypic evolutionary mechanisms of amphibians. In this review, we first summarize the recent progresses in the study of adaptive evolution of amphibians based on genomic data, and then we give perspectives regarding how to effectively identify key pathways underlying the evolution of complex traits in the genomic era, as well as directions for future research.
Studies on behavioral flexibility in response to habitat differences and degradation are crucial for developing conservation strategies for endangered species. Trachypithecus species inhabit various habitats and display different patterns of strata use; however, the effect of habitat structure on strata use remains poorly studied. Here, we investigated strata use patterns of Indo-Chinese gray langurs (Trachypithecus crepusculus) in a primary evergreen forest in Mt. Wuliang, southwest China, from June 2012 to January 2016. In addition, we compared T. crepusculus strata use and terrestriality with five other Trachypithecus species from previous studies. Unlike langurs living in karst forests, our study group was typically arboreal and spent only 2.9% of time on the ground. The group showed a preference for higher strata when resting and lower strata (<20 m) when moving. The langurs primarily used time on the ground for geophagy, but otherwise avoided the ground during feeding. These strata use patterns are similar to those of limestone langurs (T. francoisi) when using continuous forests. At the genus level (n=6 species), we found a negative relationship between habitat forest cover and terrestriality. This negative relationship was also true for the five limestone langur species, implying limestone langurs increase territoriality in response to decreased forest cover. Our results document behavioral flexibility in strata use of Trachypithecus langurs and highlight the importance of the protection of continuous forests to promote langur conservation.
The egg laying behavior of brood parasites is at the heart of studies on their co-evolution with hosts. Updating and reporting more egg laying behavior can improve our perception and insight on the brood parasitism process. During a seven years’ study period, we monitored 455 Oriental reed warbler (Acrocephalus orientalis) nests during the egg laying period, of which 250 were parasitized by common cuckoos (Cuculus canorus). We collected 53 clear videos of cuckoo parasitism, analyzed and recorded all parasitic behavior of cuckoo in details, and summarized the process of brood parasitism by the common cuckoo. Based on analyses of these field video-recordings, we proposed a new explanation for the egg removal behavior, namely the delivery hypothesis, i.e. the egg pecking and biting may facilitate parasitism, which help avoid the host’s attention and reduce host attacks, whilst egg removal is the side effect of egg pecking and biting. We concluded that common cuckoos are able to change their behaviour when hosts are around the nest, they have a set of methods to deal with host attacks and can complete parasitism boldly and smoothly at any time.
Pseudomonas plecoglossicida is a Gram-negative bacterium that is rod-shaped and has flagella. This bacterium causes visceral white spot disease and a very high mortality rate during the culture of Larimichthys crocea, which can cause serious economic losses. Analysis of transcriptome data and quantitative real-time PCR showed that the expression of dksA gene was significantly up-regulated after 48 hours of infection with Epinephelus coioides (log2FC = 3.12, p <0.001). RNAi of five shRNAs significantly reduced the expression of the gene dksA in P. plecoglossicida, and the optimal silencing efficiency was 96.23%. Compared with wild-type strains, the symptoms of visceral white spot disease in L. crocea infected with RNAi strains were reduced, the death time was delayed by 48 hours and the mortality rate was reduced by 20%. The silencing of the dksA gene leads to a large amount of down-regulation of the cellular components, flagella and ribosome assembly-related genes in P. plecoglossicida, and the significant up-regulation of the fliC gene may be a way to maintain the virulence of P. plecoglossicida. GO and KEGG results showed that L. crocea infected by RNAi strains were significantly down-regulated in inflammatory factor genes in immune-related pathways. In these immune pathways, the affected genes were associated with multiple immune response processes. The results showed that dksA was a virulence gene of P. plecoglossicida. Compared with wild strains, RNAi strains infection induced a weaker immune response in L. crocea.
Magnetic brain stimulation has contributed to the advancement of neuroscience. However, there remain challenges in the power of penetration and precision of magnetic stimulation, especially in small animals. Here, a novel strategy for magnetic brain stimulation in mice was established using a mild magnetic pulsed sequence and injection of superparamagnetic iron oxide (SPIO) nanodrugs to elevate local cortical susceptibility, namely a combined magnetic stimulation system (c-MSS). After imaging SPIO nanoparticles in the left prelimbic (PrL) cortex in mice, we were able to determine their safety and physical characteristics. Depressive-like behavior was established in mice using chronic unpredictable mild stress (CUMS) model. SPIO nanodrugs were delivered precisely to the left PrL cortex using in situ injection. A 0.1T magnetic field (adjustable frequency) was used for magnetic stimulation (5 min/session, two sessions daily). Biomarkers representing therapeutic effects were measured before and after c-MSS intervention. The c-MMS was found to rapidly improve depressive-like symptoms in CUMS mice after stimulation with a 10Hz field for 5 days, combined with increased brain-derived neurotrophic factor (BDNF) and inactivation of hypothalamic-pituitary-adrenal (HPA) axis function, which enhanced neuronal activity due to the SPIO nanoparticles mediated effect. c-MSS was shown to be safe and effective, representing a novel approach in the selective stimulation of arbitrary cortical targets in small animals, playing a bioelectric role in neural circuit regulation, including antidepressant effects for CUMS mice. This expands potential applications of magnetic stimulation and progresses brain research towards clinical application.
The Chinese sturgeon Acipenser sinensis is a large anadromous fish whose population has been seriously threatened in recent years. In this study, population genetic diversity and individual reproductive success were assessed using nuclear microsatellite markers (simple sequence repeat, SSR) and the complete mitochondrial (mtDNA) genome analysis of juveniles born in 2014. The results showed size polymorphism existed in the mtDNA genome of Chinese sturgeon, which was caused by a repeat motif. Population genetic diversity was found at a high level for both the SSR (Ho: 0.728±0.211; He: 0.779±0.122) and the mtDNA genome (H: 0.876±0.0035; Pi: 0.0011±0.0010). A positive value of the inbreeding coefficient (FIS: 0.066±0.143) was also found indicating that inbreeding had occurred. A reconstruction of sibling groups showed that there were 11 mothers and 11 fathers of Chinese sturgeons involved in reproduction in 2014. Statistical analysis indicated that the variance in individual reproductive success was not significant, and reproductive success of the parent fish was quite even (P=0.997>0.05) with Sweepstakes Reproductive Success (SRS) not occurring. These results suggested that with regard to conservation we need not worry too much about of the loss of genetic diversity due to the effects of SRS, but we must focus on having an adequate number of adults and suitable environmental conditions to ensure the fish can reproduce.
The infants during the breast-feeding period are underwent physiological and developmental remarkable changes. However, little is known about the gene expression features and the sex-specific gene expression of breast-feeding period infants. In this study, we sequenced 32 blood transcriptomes from 16 breast-feeding period infants of rhesus macaque (Macaca mulatta) and their lactating mothers. We identified 218 differentially expressed genes (DEGs) between infants and their mothers, including 91 up-regulated and 127 down-regulated DEGs in the infant group. Functional enrichment analysis with up-regulated DEGs or unique hub genes in infants both were mainly enriched in immune, growth and development. The protein-protein interaction analysis also revealed that genes at the key positions in infants were mainly related to development and immunity. However, we only detected 23 DEGs between female and male infants, including two DEGs located on Chromosome X and 11 DEGs located on Chromosome Y. One of the 23 DEGs was TMF1 regulated nuclear protein 1 (Trnp1), which was highly expressed in the female infants, was crucial to control the tangential and radial expansion of the cerebral cortex in mammals. Our study provides novel insights into the gene expression features of breast-feeding period infants in non-human primate, and also reveals the sex-specific gene expression between these infants.
Intestinal biopsy is a basic experimental method for studying pathological changes in the intestinal tract during human immunodeficiency virus (HIV) infection. In this study, jejunal resection and anastomosis were successfully performed in 12 Chinese rhesus macaques (Macaca mulatta). The sampled gut tissues were then examined by hematoxylin and eosin (H&E) staining, electron microscopy, flow cytometry, immunofluorescence detection, and RNA quality analysis to ensure suitability for histological, physiological, pathological, and immunological detection, as well as mechanistic analysis at the cellular and molecular level. Importantly, the surgery did not affect the ratio or number of immune cells in peripheral blood or the concentration of lipids, proteins, and vitamins in plasma, which are important indicators of nutritional status. Our results thus indicated that jejunal resection and anastomosis are feasible, and that immune homeostasis and intestinal barrier integrity are not altered by surgery. All macaques recovered well (except for one), with no postoperative complications. Therefore, this animal surgery may be applicable for longitudinal intestinal research related to diseases such as acquired immunodeficiency syndrome (AIDS).
Sleep serves an indispensable function in human health, and its disorders always bring about a cascade of negative consequences. As our closest phylogenetic relatedness, nonhuman primates (NHPs) are especially valuable for the comparative study of sleep, with tremendous potential to provide critical improvements in our understanding of human sleep and sleep disorders. Previous work on measuring sleep in NHPs has been mostly carried out using electroencephalography or videography. In this study, simultaneous videography and actigraphy were recorded in 10 cynomolgus monkeys (Macaca fasciculari) during seven nights (12 hours per night). The durations of wake, transitional sleep and relaxed sleep were scored by analysis of animal behaviors from videography and actigraphy data, using the same behavioral criteria for each state. Results were then compared, and it was found that the actigraphy appeared to constitute a reliable methodology for scoring the state of sleep in monkeys, showing a significant correlation in comparison with those scored by videography. Further epoch by epoch analysis indicated that the actigraphy method was more suitable for scoring the state of relaxed sleep as it can correctly identified 97.569% of relaxed sleep in comparison with video analysis. Only 34 epochs (0.128%) and 611 epochs (2.303%) were interpreted as wake and transitional sleep differently from the videography analysis. The present study validated the behavioral criteria and the actigraphy methodology for scoring sleep, which can be considered as a useful and a complementary technique to electroencephalography and/or videography analysis for sleep studies in non-human primates.