The Asian tiger mosquito, Aedes albopictus, is a highly successful invasive species that transmits a number of human viral diseases, including dengue and Chikungunya fevers. This species has a large genome with significant population-based size variation. The complete genome sequence was determined for the Foshan strain, an established laboratory colony derived from wild mosquitoes from southeastern China, a region within the historical range of the origin of the species. The genome comprises 1,967 Mb, the largest mosquito genome sequenced to date, and its size results principally from an abundance of repetitive DNA classes. In addition, expansions of the numbers of members in gene families involved in insecticide-resistance mechanisms, diapause, sex determination, immunity, and olfaction also contribute to the larger size. Portions of integrated flavivirus-like genomes support a shared evolutionary history of association of these viruses with their vector. The large genome repertory may contribute to the adaptability and success of Ae. albopictus as an invasive species.
ischemic stroke is one of the leading causes of mortality and disability worldwide. However, there is a current lack of effective therapies available. as the resident macrophages of the brain, microglia can monitor the microenvironment and initiate immune responses. in response to various brain injuries, such as ischemic stroke, microglia are activated and polarized into the proinflammatory M1 phenotype or the anti-inflammatory M2 phenotype. The immunomodulatory molecules, such as cytokines and chemokines, generated by these microglia are closely associated with secondary brain damage or repair, respectively, following ischemic stroke. it has been shown that M1 microglia promote secondary brain damage, whilst M2 microglia facilitate recovery following stroke. in addition, autophagy is also reportedly involved in the pathology of ischemic stroke through regulating the activation and function of microglia. Therefore, this review aimed to provide a comprehensive overview of microglia activation, their functions and changes, and the modulators of these processes, including transcription factors, membrane receptors, ion channel proteins and genes, in ischemic stroke. The effects of autophagy on microglia polarization in ischemic stroke were also reviewed. Finally, future research areas of ischemic stroke and the implications of the current knowledge for the development of novel therapeutics for ischemic stroke were identified. Contents 1. introduction 2. Microglia 3. Modulatory mechanisms of microglia polarization 4. autophagy 5. conclusions
Nacre, the iridescent material found in pearls and shells of molluscs, is formed through an extraordinary process of matrix-assisted biomineralization. Despite recent advances, many aspects of the biomineralization process and its evolutionary origin remain unknown. The pearl oyster Pinctada fucata martensii is a well-known master of biomineralization, but the molecular mechanisms that underlie its production of shells and pearls are not fully understood. We sequenced the highly polymorphic genome of the pearl oyster and conducted multi-omic and biochemical studies to probe nacre formation. We identified a large set of novel proteins participating in matrix-framework formation, many in expanded families, including components similar to that found in vertebrate bones such as collagen-related VWA-containing proteins, chondroitin sulfotransferases, and regulatory elements. Considering that there are only collagen-based matrices in vertebrate bones and chitin-based matrices in most invertebrate skeletons, the presence of both chitin and elements of collagen-based matrices in nacre suggests that elements of chitin- and collagen-based matrices have deep roots and might be part of an ancient biomineralizing matrix. Our results expand the current shell matrix-framework model and provide new insights into the evolution of diverse biomineralization systems.
Pearl oyster Pinctada martensii is cultured for production of pearl in China. It needs to implant a mantle graft cut from a donor oyster and a seed nucleus into the gonad of the host oyster to produce a pearl. Pearl sac surrounding the nucleus is formed by the proliferation of the implanted mantle graft from the outer mantle epithelial cells in the host oyster. The pearl sac is responsible for production of a cultured pearl. A comprehensive transcriptome analysis on pearl sac will help to understand the mechanism on pearl formation and immune response of host oyster after nucleus implantation. In the present study, 39,400,004 reads were produced from the pearl sac using RNA-sequence technology and then assembled into 102,762 unigenes. More than 22.4% of these unigenes were possibly involved in approximately 219 known signaling pathways. A total of 37,188 unigenes were annotated based on sequences similarities with known proteins. Fifty-one biomineralization-related unigenes and 268 immune-related unigenes were not previously detected in P. martensii. The un-annotated unigenes may be some genes specifically existed in P. martensii. These annotated or un-annotated unigenes in the present studies were valuable for the future investigation on molecular mechanism of pearl formation and immune response of the species.
The Asian tiger mosquito, Aedes albopictus isa major vector of dengue in mainland China. Dengue epidemics have spread from the southern coastal regions to the relatively northern and western regions since 1990s. Dengue has become an emerging public health problem in the southern coastal regions. microRNAs(miRNAs) are short non-coding RNAs that regulate gene expression at the post transcription allevel. A highly abundant miRNA, miR-252, was induced more than threefold after dengue virus serotype 2 (DENV-2) infection in the Ae. albopictus C6/36 cellline. Transfection with miR-252 inhibitor resulted in the increase of DENV-2 RNA copies and the up-regulation of DENV-2 envelop protein(E protein) expression, whereas over expression of miR-252 with its mimic decreased DENV RNA copies and the down-regulation of E protein expression. MiR-252 mimic reduced luciferase activity of a luciferase reporter that contained the predicted miR-252 target on the DENV-2 envelope gene sequence. The present results indicated that the miR-252 of Ae. albopictus could regulate the gene expression of DENV-2 E protein and may act asa cellular antiviral regulator in Ae. albopictus.
MicroRNAs (miRNAs) are short-nucleotide RNA molecules that function as negative regulators of gene expression in various organisms. However, miRNAs of Pinctada martensii have not been reported yet. P. martensii is one of the main species cultured for marine pearl production in China and Japan. In order to obtain the repertoire of miRNAs in P. martensii, we constructed and sequenced small RNA libraries prepared from P. martensii by Solexa deep sequencing technology and got a total of 27,479,838 reads representing 3,176,630 distinct sequences. After removing tRNAs, rRNAs, snRNAs, and snoRNAs, 10,596,306 miRNA reads representing 18,050 distinct miRNA reads were obtained. Based on sequence similarity and hairpin structure prediction, 258 P. martensii miRNAs (pm-miRNA) were identified. Among these pm-miRNAs, 205 were conserved across the species, whereas 53 were specific for P. martensii. The 3' end sequence of U6 snRNA was obtained from P. martensii by 3' rapid amplification of cDNA end PCR reaction and sequence-directed cloning. Eight conserved pm-miRNAs and two novel pm-miRNAs were validated by stem-loop quantitative real-time PCR with U6 snRNA as an internal reference gene. pm-miRNAs and the reported biomineralization-related genes were subjected to target analysis by using target prediction tools. Some of the pm-miRNAs, such as miR-2305 and miR-0046, were predicted to participate in biomineralization by regulating the biomineralization-related genes. Thus, this study demonstrated a large-scale characterization of pm-miRNAs and their potential function in biomineralization, providing a foundation to understand shell formation.
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