Arthropod-borne viruses (arboviruses) circulate in nature between arthropod vectors and vertebrate hosts. Arboviruses often cause devastating diseases in vertebrate hosts, but they typically do not ...cause significant pathology in their arthropod vectors. Following oral acquisition of a viremic bloodmeal from a vertebrate host, the arbovirus disease cycle requires replication in the cellular environment of the arthropod vector. Once the vector has become systemically and persistently infected, the vector is able to transmit the virus to an uninfected vertebrate host. In order to systemically infect the vector, the virus must cope with innate immune responses and overcome several tissue barriers associated with the midgut and the salivary glands. In this review we describe, in detail, the typical arbovirus infection route in competent mosquito vectors. Based on what is known from the literature, we explain the nature of the tissue barriers that arboviruses are confronted with in a mosquito vector and how arboviruses might surmount these barriers. We also point out controversial findings to highlight particular areas that are not well understood and require further research efforts.
...even in the AcMNPV genome, roughly half of the genes have no assigned function, meaning that there are probably many more interesting baculovirus accessory genes whose functions are waiting to ...be discovered. Since BV can bind to and enter many kinds of vertebrate and invertebrate cells, baculovirus host range is more complex than just receptor binding, and the determinants of host range are poorly characterized. ...invertebrate antiviral immunity is still a young field, and little is known about immune responses of insects against baculoviruses.
In vivo targeted gene disruption is a powerful tool to study gene function. Thus far, two tools for genome editing in Aedes aegypti have been applied, zinc-finger nucleases (ZFN) and transcription ...activator-like effector nucleases (TALEN). As a promising alternative to ZFN and TALEN, which are difficult to produce and validate using standard molecular biological techniques, the clustered regularly interspaced short palindromic repeats/CRISPR-associated sequence 9 (CRISPR/Cas9) system has recently been discovered as a "do-it-yourself" genome editing tool. Here, we describe the use of CRISPR/Cas9 in the mosquito vector, Aedes aegypti. In a transgenic mosquito line expressing both Dsred and enhanced cyan fluorescent protein (ECFP) from the eye tissue-specific 3xP3 promoter in separated but tightly linked expression cassettes, we targeted the ECFP nucleotide sequence for disruption. When supplying the Cas9 enzyme and two sgRNAs targeting different regions of the ECFP gene as in vitro transcribed mRNAs for germline transformation, we recovered four different G1 pools (5.5% knockout efficiency) where individuals still expressed DsRed but no longer ECFP. PCR amplification, cloning, and sequencing of PCR amplicons revealed indels in the ECFP target gene ranging from 2-27 nucleotides. These results show for the first time that CRISPR/Cas9 mediated gene editing is achievable in Ae. aegypti, paving the way for further functional genomics related studies in this mosquito species.
Abstract The mechanisms used by baculoviruses to exit the midgut and cause systemic infection of their insect hosts have been debated for decades. After being ingested, baculoviruses reach the ...midgut, where several host barriers need to be overcome in order to establish successful infection. One of these barriers is the basal lamina, a presumably virus-impermeable extracellular layer secreted by the epithelial cells lining the midgut and trachea. This review discusses new evidence that demonstrates how these viruses breach the basal lamina and establish efficient systemic infections. The biochemical mechanisms involved in dismantling basal lamina during baculovirus infection may also provide new insights into the process of basal lamina remodeling in invertebrate and vertebrate animals.
Abstract
This meta-analysis sought to expand upon neurobiological models of mindfulness through investigation of inherent brain network connectivity outcomes, indexed via resting state functional ...connectivity (rsFC). We conducted a systematic review and meta-analysis of rsFC as an outcome of mindfulness training (MT) relative to control, with the hypothesis that MT would increase cross-network connectivity between nodes of the Default Mode Network (DMN), Salience Network (SN), and Frontoparietal Control Network (FPCN) as a mechanism of internally-oriented attentional control. Texts were identified from the databases: MEDLINE/PubMed, ERIC, PSYCINFO, ProQuest, Scopus, and Web of Sciences; and were screened for inclusion based on experimental/quasi-experimental trial design and use of mindfulness-based training interventions. RsFC effects were extracted from twelve studies (mindfulness
n
= 226; control
n
= 204). Voxel-based meta-analysis revealed significantly greater rsFC (MT > control) between the left middle cingulate (
Hedge’s g
= .234,
p
= 0.0288,
I
2
= 15.87), located within the SN, and the posterior cingulate cortex, a focal hub of the DMN. Egger’s test for publication bias was nonsignificant, bias = 2.17,
p
= 0.162. In support of our hypothesis, results suggest that MT targets internetwork (SN-DMN) connectivity implicated in the flexible control of internally-oriented attention.
The baculoviral chitinase (CHIA) and cathepsin (V-CATH) enzymes promote terminal insect host liquefaction, which aids viral progeny dissemination. Recombinant Autographa californica ...nucleopolyhedrovirus (AcMNPV)-derived viruses were previously generated with reprogrammed
transcription by replacing the native promoter with the AcMNPV
(
) or core protein (
) promoter sequences, but of both these
-reprogrammed viruses lacked
transcription and V-CATH enzymatic activity. Here, we report that dual
/
promoter reprogramming of the adjacent
genes resulted in modulated temporal transcription of both genes without impacting infectious budded virus production. These promoter changes increased CHIA and V-CATH enzyme activities in infected
-derived cultured cells and
larvae. In addition, larvae infected with the dual reprogrammed virus had earlier mortalities and liquefaction. This recombinant baculovirus, lacking exogenous genomic elements and increased
expression levels, may be desirable for and amenable to producing enhanced baculovirus-based biopesticides.
Baculovirus-infected larvae release progeny viral occlusion bodies (OBs) to enable cyclical virus transmission to new hosts. The alphabaculovirus chitinase and cathepsin enzymes cause terminal ...liquefaction of host insect cadavers, aiding OB dispersal. The mechanism of cell lysis required to release the OBs is unclear but here we show Autographa californica multiple nucleopolyhedrovirus cathepsin protease activity is required for efficient release of the host tissue-degrading chitinase and cathepsin enzymes and critical for release of progeny OBs from virus-infected cells. Comparisons between viruses containing or lacking cathepsin indicate that cathepsin was necessary for OB release into cultured cell media or hemolymph of insects. In addition, pharmacological inhibition of cysteine protease activity in cells during infection blocked maturation of active cathepsin and OB release from infected cells. Together, these results suggest an important link between baculovirus-induced cell lysis, the concomitant maturation of cathepsin, and cellular release of chitinase, cathepsin and progeny OBs from cells.
•Cellular release of progeny viral OBs requires mature viral cathepsin cysteine protease.•Pharmacological inhibition of cysteine protease activity during infection by wildtype virus blocks cellular release of progeny viral OBs.•Expression of the viral cathepsin protease enhances cellular release of viral chitinase and cathepsin.•Cellular regulation of chitinase and cathepsin is important for dissemination of progeny viral OBs.
Marine ecosystems are globally threatened by human activities, but some areas, such as those affected by abandoned industrial plants, show an overlap of acute and chronic impacts, which determine a ...considerable deterioration of their health status. Here we report the results of a research conducted on coastal sewers that discharge their loads in the highly contaminated area of Bagnoli-Coroglio (Tyrrhenian Sea, Western Mediterranean). The sampling area is characterized by heavy industrial activities (a steel plant using coal, iron and limestone) started in 1905 and ceased in 1990, which left widespread heavy metals and hydrocarbon contamination. After taking into account the potential influence of sediment grain size ranges through their inclusion as covariates in the analysis, we tested the potential impact of sewage discharge on the total abundance and multivariate structure of meiofaunal assemblages, as well as on the abundance of single taxa. The organic matter was analysed in terms of total phytopigment and biopolymeric carbon concentrations. Nematoda, Copepoda (including their nauplii), and Tardigrada were the most abundant meiofaunal taxa at all sites, but nematodes did not show a consistent pattern relative to the sewage outfalls. However, the sewer located in the historically most contaminated area showed a minimal abundance of all taxa, including nematodes, while copepods were relatively less abundant at the two southernmost sewers. Comparing the north vs. south site of the sewers, higher meiofaunal abundances were observed in the southward part, likely as a result of the local circulation. The results of this study indicate the general adaptation of meiofauna to multiple stressors (sewage discharge, superimposed to chronic industrial contamination) and its likely modulation by other local processes. They also provide relevant baseline information for future restoration interventions that would take into account the spatial variation of target organisms as needed.
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•Sediment collected at two distances and on opposite sides from four sewers in a post-industrial area•Changes in meiofaunal assemblage composition assessed as response variables•The sewer in the historically most contaminated area showed a collapse of all taxa.•Copepods decreased significantly at the two southernmost sewers.•Novel insights into the potential impact of multiple stressors and for future restoration
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