scholarly journals Coral-associated viral communities show high levels of diversity and host auxiliary functions

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e4054 ◽  
Author(s):  
Karen D. Weynberg ◽  
Patrick W. Laffy ◽  
Elisha M. Wood-Charlson ◽  
Dmitrij Turaev ◽  
Thomas Rattei ◽  
...  

Stony corals (Scleractinia) are marine invertebrates that form the foundation and framework upon which tropical reefs are built. The coral animal associates with a diverse microbiome comprised of dinoflagellate algae and other protists, bacteria, archaea, fungi and viruses. Using a metagenomics approach, we analysed the DNA and RNA viral assemblages of seven coral species from the central Great Barrier Reef (GBR), demonstrating that tailed bacteriophages of the Caudovirales dominate across all species examined, and ssDNA viruses, notably the Microviridae, are also prevalent. Most sequences with matches to eukaryotic viruses were assigned to six viral families, including four Nucleocytoplasmic Large DNA Viruses (NCLDVs) families: Iridoviridae, Phycodnaviridae, Mimiviridae, and Poxviridae, as well as Retroviridae and Polydnaviridae. Contrary to previous findings, Herpesvirales were rare in these GBR corals. Sequences of a ssRNA virus with similarities to the dinornavirus, Heterocapsa circularisquama ssRNA virus of the Alvernaviridae that infects free-living dinoflagellates, were observed in three coral species. We also detected viruses previously undescribed from the coral holobiont, including a virus that targets fungi associated with the coral species Acropora tenuis. Functional analysis of the assembled contigs indicated a high prevalence of latency-associated genes in the coral-associated viral assemblages, several host-derived auxiliary metabolic genes (AMGs) for photosynthesis (psbA, psbD genes encoding the photosystem II D1 and D2 proteins respectively), as well as potential nematocyst toxins and antioxidants (genes encoding green fluorescent-like chromoprotein). This study expands the currently limited knowledge on coral-associated viruses by characterising viral composition and function across seven GBR coral species.

Author(s):  
Xinyue Zhang ◽  
Erlie Su ◽  
Shanshan Li ◽  
Xiehui Chen ◽  
Zhihua Fan ◽  
...  

The diversity and transcription efficiency of GH1 family β-glucosidase genes were investigated in natural and inoculated composts using a DNA clone library and real-time qPCR. Compositional differences were observed in the functional community between both composting processes. Proteobacteria, Actinobacteria, Firmicutes, and Chloroflexi were the dominant phyla. Twenty representative β-glucosidase genes were quantitatively analyzed from DNA and RNA pools. Principal component analysis and Pearson’s correlation analysis showed that cellulose degradation is correlated with the composition and succession of functional microbial communities, and this correlation was mainly observed in Proteobacteria and Actinobacteria. Compared with inoculated compost, the functional microbial communities in natural compost with a low diversity index exhibited weak buffering capacity for function in response to environmental changes. This may explain the consistency and dysfunction of cellulose degradation and transcriptional regulation by dominant β-glucosidase genes. Except for the β-glucosidase genes encoding constitutive enzymes, individual β-glucosidase genes responded to environmental changes more drastically than the group β-glucosidase genes. Correlation results suggested that β-glucosidase genes belonging to Micrococcales played an important role in the regulation of intracellular β-glucosidase. These results indicated that the responses of functional microorganisms were different during both composting processes, and were reflected at both the individual and group levels.


2015 ◽  
Vol 89 (17) ◽  
pp. 8909-8921 ◽  
Author(s):  
Catherine Béliveau ◽  
Alejandro Cohen ◽  
Don Stewart ◽  
Georges Periquet ◽  
Abdelmadjid Djoumad ◽  
...  

ABSTRACTPolydnaviruses form a group of unconventional double-stranded DNA (dsDNA) viruses transmitted by endoparasitic wasps during egg laying into caterpillar hosts, where viral gene expression is essential to immature wasp survival. A copy of the viral genome is present in wasp chromosomes, thus ensuring vertical transmission. Polydnaviruses comprise two taxa,BracovirusandIchnovirus, shown to have distinct viral ancestors whose genomes were “captured” by ancestral wasps. While evidence indicates that bracoviruses derive from a nudivirus ancestor, the identity of the ichnovirus progenitor remains unknown. In addition, ichnoviruses are found in two ichneumonid wasp subfamilies, Campopleginae and Banchinae, where they constitute morphologically and genomically different virus types. To address the question of whether these two ichnovirus subgroups have distinct ancestors, we used genomic, proteomic, and transcriptomic analyses to characterize particle proteins of the banchineGlypta fumiferanaeichnovirus and the genes encoding them. Several proteins were found to be homologous to those identified earlier for campoplegine ichnoviruses while the corresponding genes were located in clusters of the wasp genome similar to those observed previously in a campoplegine wasp. However, for the first time in a polydnavirus system, these clusters also revealed sequences encoding enzymes presumed to form the replicative machinery of the progenitor virus and observed to be overexpressed in the virogenic tissue. Homology searches pointed to nucleocytoplasmic large DNA viruses as the likely source of these genes. These data, along with an analysis of the chromosomal form of five viral genome segments, provide clear evidence for the relatedness of the banchine and campoplegine ichnovirus ancestors.IMPORTANCERecent work indicates that the two recognized polydnavirus taxa,BracovirusandIchnovirus, are derived from distinct viruses whose genomes integrated into the genomes of ancestral wasps. However, the identity of the ichnovirus ancestor is unknown, and questions remain regarding the possibility that the two described ichnovirus subgroups, banchine and campoplegine ichnoviruses, have distinct origins. Our study provides unequivocal evidence that these two ichnovirus types are derived from related viral progenitors. This suggests that morphological and genomic differences observed between the ichnovirus lineages, including features unique to banchine ichnovirus genome segments, result from evolutionary divergence either before or after their endogenization. Strikingly, analysis of selected wasp genomic regions revealed genes presumed to be part of the replicative machinery of the progenitor virus, shedding new light on the likely identity of this virus. Finally, these genes could well play a role in ichnovirus replication as they were overexpressed in the virogenic tissue.


Author(s):  
Patricia G. Arscott ◽  
Gil Lee ◽  
Victor A. Bloomfield ◽  
D. Fennell Evans

STM is one of the most promising techniques available for visualizing the fine details of biomolecular structure. It has been used to map the surface topography of inorganic materials in atomic dimensions, and thus has the resolving power not only to determine the conformation of small molecules but to distinguish site-specific features within a molecule. That level of detail is of critical importance in understanding the relationship between form and function in biological systems. The size, shape, and accessibility of molecular structures can be determined much more accurately by STM than by electron microscopy since no staining, shadowing or labeling with heavy metals is required, and there is no exposure to damaging radiation by electrons. Crystallography and most other physical techniques do not give information about individual molecules.We have obtained striking images of DNA and RNA, using calf thymus DNA and two synthetic polynucleotides, poly(dG-me5dC)·poly(dG-me5dC) and poly(rA)·poly(rU).


Genetics ◽  
2003 ◽  
Vol 165 (2) ◽  
pp. 613-621 ◽  
Author(s):  
Douglas R Dorer ◽  
Jamie A Rudnick ◽  
Etsuko N Moriyama ◽  
Alan C Christensen

Abstract Within the unique Triplo-lethal region (Tpl) of the Drosophila melanogaster genome we have found a cluster of 20 genes encoding a novel family of proteins. This family is also present in the Anopheles gambiae genome and displays remarkable synteny and sequence conservation with the Drosophila cluster. The family is also present in the sequenced genome of D. pseudoobscura, and homologs have been found in Aedes aegypti mosquitoes and in four other insect orders, but it is not present in the sequenced genome of any noninsect species. Phylogenetic analysis suggests that the cluster evolved prior to the divergence of Drosophila and Anopheles (250 MYA) and has been highly conserved since. The ratio of synonymous to nonsynonymous substitutions and the high codon bias suggest that there has been selection on this family both for expression level and function. We hypothesize that this gene family is Tpl, name it the Osiris family, and consider possible functions. We also predict that this family of proteins, due to the unique dosage sensitivity and the lack of homologs in noninsect species, would be a good target for genetic engineering or novel insecticides.


2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Peng Chen ◽  
Hongyang Jing ◽  
Mingtao Xiong ◽  
Qian Zhang ◽  
Dong Lin ◽  
...  

AbstractThe genes encoding for neuregulin1 (NRG1), a growth factor, and its receptor ErbB4 are both risk factors of major depression disorder and schizophrenia (SZ). They have been implicated in neural development and synaptic plasticity. However, exactly how NRG1 variations lead to SZ remains unclear. Indeed, NRG1 levels are increased in postmortem brain tissues of patients with brain disorders. Here, we studied the effects of high-level NRG1 on dendritic spine development and function. We showed that spine density in the prefrontal cortex and hippocampus was reduced in mice (ctoNrg1) that overexpressed NRG1 in neurons. The frequency of miniature excitatory postsynaptic currents (mEPSCs) was reduced in both brain regions of ctoNrg1 mice. High expression of NRG1 activated LIMK1 and increased cofilin phosphorylation in postsynaptic densities. Spine reduction was attenuated by inhibiting LIMK1 or blocking the NRG1–LIMK1 interaction, or by restoring NRG1 protein level. These results indicate that a normal NRG1 protein level is necessary for spine homeostasis and suggest a pathophysiological mechanism of abnormal spines in relevant brain disorders.


Hematology ◽  
2009 ◽  
Vol 2009 (1) ◽  
pp. 344-350 ◽  
Author(s):  
Christoph Klein

Abstract Congenital neutropenia comprises a variety of genetically heterogeneous phenotypic traits. Molecular elucidation of the underlying genetic defects has yielded important insights into the physiology of neutrophil differentiation and function. Non-syndromic variants of congenital neutropenia are caused by mutations in ELA2, HAX1, GFI1, or WAS. Syndromic variants of congenital neutropenia may be due to mutations in genes controlling glucose metabolism (SLC37A4, G6PC3) or lysosomal function (LYST, RAB27A, ROBLD3/p14, AP3B1, VPS13B). Furthermore, defects in genes encoding ribosomal proteins (SBDS, RMRP) and mitochondrial proteins (AK2, TAZ) are associated with congenital neutropenia syndromes. Despite remarkable progress in the field, many patients with congenital neutropenia cannot yet definitively be classified by genetic terms. This review addresses diagnostic and therapeutic aspects of congenital neutropenia and covers recent molecular and pathophysiological insights of selected congenital neutropenia syndromes.


2021 ◽  
Author(s):  
Rajan Saha Raju ◽  
Abdullah Al Nahid ◽  
Preonath Shuvo ◽  
Rashedul Islam

AbstractTaxonomic classification of viruses is a multi-class hierarchical classification problem, as taxonomic ranks (e.g., order, family and genus) of viruses are hierarchically structured and have multiple classes in each rank. Classification of biological sequences which are hierarchically structured with multiple classes is challenging. Here we developed a machine learning architecture, VirusTaxo, using a multi-class hierarchical classification by k-mer enrichment. VirusTaxo classifies DNA and RNA viruses to their taxonomic ranks using genome sequence. To assign taxonomic ranks, VirusTaxo extracts k-mers from genome sequence and creates bag-of-k-mers for each class in a rank. VirusTaxo uses a top-down hierarchical classification approach and accurately assigns the order, family and genus of a virus from the genome sequence. The average accuracies of VirusTaxo for DNA viruses are 99% (order), 98% (family) and 95% (genus) and for RNA viruses 97% (order), 96% (family) and 82% (genus). VirusTaxo can be used to detect taxonomy of novel viruses using full length genome or contig sequences.AvailabilityOnline version of VirusTaxo is available at https://omics-lab.com/virustaxo/.


1999 ◽  
Vol 146 (2) ◽  
pp. 333-344 ◽  
Author(s):  
Chavela M. Carr ◽  
Eric Grote ◽  
Mary Munson ◽  
Frederick M. Hughson ◽  
Peter J. Novick

Proteins of the Sec1 family have been shown to interact with target-membrane t-SNAREs that are homologous to the neuronal protein syntaxin. We demonstrate that yeast Sec1p coprecipitates not only the syntaxin homologue Ssop, but also the other two exocytic SNAREs (Sec9p and Sncp) in amounts and in proportions characteristic of SNARE complexes in yeast lysates. The interaction between Sec1p and Ssop is limited by the abundance of SNARE complexes present in sec mutants that are defective in either SNARE complex assembly or disassembly. Furthermore, the localization of green fluorescent protein (GFP)-tagged Sec1p coincides with sites of vesicle docking and fusion where SNARE complexes are believed to assemble and function. The proposal that SNARE complexes act as receptors for Sec1p is supported by the mislocalization of GFP-Sec1p in a mutant defective for SNARE complex assembly and by the robust localization of GFP-Sec1p in a mutant that fails to disassemble SNARE complexes. The results presented here place yeast Sec1p at the core of the exocytic fusion machinery, bound to SNARE complexes and localized to sites of secretion.


2019 ◽  
Author(s):  
Cassandra K. Hayne ◽  
Casey A. Schmidt ◽  
A. Gregory Matera ◽  
Robin E. Stanley

ABSTRACTThe splicing of tRNA introns is a critical step in pre-tRNA maturation. In archaea and eukaryotes, tRNA intron removal is catalyzed by the tRNA splicing endonuclease (TSEN) complex. Eukaryotic TSEN is comprised of four core subunits (TSEN54, TSEN2, TSEN34, and TSEN15). The human TSEN complex additionally co-purifies with the polynucleotide kinase CLP1; however, CLP1’s role in tRNA splicing remains unclear. Mutations in genes encoding all four TSEN subunits, as well as CLP1, are known to cause neurodegenerative disorders, yet the mechanisms underlying the pathogenesis of these disorders are unknown. Here, we developed a recombinant system that produces active TSEN complex. Co-expression of all four TSEN subunits is required for efficient formation and function of the complex. We show that human CLP1 associates with the active TSEN complex, but is not required for tRNA intron cleavage in vitro. Moreover, RNAi knockdown of the Drosophila CLP1 orthologue, cbc, promotes biogenesis of mature tRNAs and circularized tRNA introns (tricRNAs) in vivo. Collectively, these and other findings suggest that CLP1/cbc plays a regulatory role in tRNA splicing by serving as a negative modulator of the direct tRNA ligation pathway in animal cells.


2020 ◽  
Vol 48 (4) ◽  
pp. 1569-1581 ◽  
Author(s):  
Gwenny Cackett ◽  
Michal Sýkora ◽  
Finn Werner

African swine fever virus (ASFV) represents a severe threat to global agriculture with the world's domestic pig population reduced by a quarter following recent outbreaks in Europe and Asia. Like other nucleocytoplasmic large DNA viruses, ASFV encodes a transcription apparatus including a eukaryote-like RNA polymerase along with a combination of virus-specific, and host-related transcription factors homologous to the TATA-binding protein (TBP) and TFIIB. Despite its high impact, the molecular basis and temporal regulation of ASFV transcription is not well understood. Our lab recently applied deep sequencing approaches to characterise the viral transcriptome and gene expression during early and late ASFV infection. We have characterised the viral promoter elements and termination signatures, by mapping the RNA-5′ and RNA-3′ termini at single nucleotide resolution. In this review, we discuss the emerging field of ASFV transcripts, transcription, and transcriptomics.


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