RNA-binding proteins (RBPs) are central components of gene regulatory networks. The differentiation of heterocysts in filamentous cyanobacteria is an example of cell differentiation in prokaryotes. Although multiple non-coding transcripts are involved in this process, no RBPs have been implicated thus far.
View Article and Find Full Text PDFWhile previous research suggests that peer and teacher preferences are linked to adolescents' peer relationships, the specific impact of peer and teacher (dis)liking on adolescents' friendship networks is not fully understood. This study used longitudinal social network analysis to examine how peer (dis)liking and perceptions of teacher (dis)liking predicted friendship selection among Chinese adolescents. Questionnaires were administered to a sample of 2566 students (48.
View Article and Find Full Text PDFHow CRISPR-Cas systems defend bacteria and archaea against invading genetic elements is well understood, but less is known about their regulation. In the cyanobacterium Synechocystis sp. PCC 6803, the expression of one of the three different CRISPR-Cas systems responds to changes in environmental conditions.
View Article and Find Full Text PDFRNA degradation is critical for synchronising gene expression with changing conditions in prokaryotic and eukaryotic organisms. In bacteria, the preference of the central ribonucleases RNase E, RNase J and RNase Y for 5'-monophosphorylated RNAs is considered important for RNA degradation. For RNase E, the underlying mechanism is termed 5' sensing, contrasting to the alternative 'direct entry' mode, which is independent of monophosphorylated 5' ends.
View Article and Find Full Text PDFThis study examined whether having vulnerable friends helps or hurts victimized and depressed (i.e., vulnerable) adolescents and whether this depends on classroom supportive norms.
View Article and Find Full Text PDFSynthetic biology approaches toward the development of cyanobacterial producer strains require the availability of appropriate sets of plasmid vectors. A factor for the industrial usefulness of such strains is their robustness against pathogens, such as bacteriophages infecting cyanobacteria. Therefore, it is of great interest to understand the native plasmid replication systems and the CRISPR-Cas based defense mechanisms already present in cyanobacteria.
View Article and Find Full Text PDFEndoribonucleases govern the maturation and degradation of RNA and are indispensable in the posttranscriptional regulation of gene expression. A key endoribonuclease in Gram-negative bacteria is RNase E. To ensure an appropriate supply of RNase E, some bacteria, such as , feedback-regulate RNase E expression via the 5'-untranslated region (5' UTR) in .
View Article and Find Full Text PDFThe marine picocyanobacterium contributes significantly to global primary production, and its abundance and diversity is shaped in part by viral infection. Here, we identified a cyanophage-encoded MarR-type transcription factor that induces the gene expression of host MED4 endoribonuclease (RNase) E during phage infection. The increase in transcript levels relies on the phage (p)MarR-mediated activation of an alternative promoter that gives rise to a truncated yet enzymatically fully functional RNase E isoform.
View Article and Find Full Text PDFRNA helicases play crucial functions in RNA biology. In plants, RNA helicases are encoded by large gene families, performing roles in abiotic stress responses, development, the post-transcriptional regulation of gene expression as well as house-keeping functions. Several of these RNA helicases are targeted to the organelles, mitochondria and chloroplasts.
View Article and Find Full Text PDFPhycobilisomes (PBSs), the principal cyanobacterial antenna, are among the most efficient macromolecular structures in nature, and are used for both light harvesting and directed energy transfer to the photosynthetic reaction center. However, under unfavorable conditions, excess excitation energy needs to be rapidly dissipated to avoid photodamage. The orange carotenoid protein (OCP) senses light intensity and induces thermal energy dissipation under stress conditions.
View Article and Find Full Text PDFPhycobilisomes are the major pigment-protein antenna complexes that perform photosynthetic light harvesting in cyanobacteria, rhodophyte, and glaucophyte algae. Up to 50% of the cellular nitrogen can be stored in their giant structures. Accordingly, upon nitrogen depletion, phycobilisomes are rapidly degraded following an intricate genetic program.
View Article and Find Full Text PDFUnderstanding how microorganisms adjust their metabolism to maintain their ability to cope with short-term environmental variations constitutes one of the major current challenges in microbial ecology. Here, the best physiologically characterized marine strain, WH7803, was exposed to modulated light/dark cycles or acclimated to continuous high-light (HL) or low-light (LL), then shifted to various stress conditions, including low (LT) or high temperature (HT), HL and ultraviolet (UV) radiations. Physiological responses were analyzed by measuring time courses of photosystem (PS) II quantum yield, PSII repair rate, pigment ratios and global changes in gene expression.
View Article and Find Full Text PDFSmall regulatory RNAs and antisense RNAs play important roles in the regulation of gene expression in bacteria but are underexplored, especially in natural populations. While environmentally relevant microbes often are not amenable to genetic manipulation or cannot be cultivated in the laboratory, extensive metagenomic and metatranscriptomic datasets for these organisms might be available. Hence, dedicated workflows for specific analyses are needed to fully benefit from this information.
View Article and Find Full Text PDFThe arrangement of functionally-related genes in operons is a fundamental element of how genetic information is organized in prokaryotes. This organization ensures coordinated gene expression by co-transcription. Often, however, alternative genetic responses to specific stress conditions demand the discoordination of operon expression.
View Article and Find Full Text PDFNewcastle disease virus (NDV) vectors expressing avian influenza virus (AIV) haemagglutinin (HA) of subtype H5 simultaneously protect chickens from Newcastle disease (ND) as well as avian influenza (AI). The expressed, membrane-bound surface protein HA is incorporated into virions while soluble HA has been described as a potent antigen. We tested whether co-expression of both HA variants from the same NDV vector increased the overall level of HA, which could be important for optimal immunogenicity.
View Article and Find Full Text PDFMarine cyanobacteria of the genus Prochlorococcus thrive in high cell numbers throughout the euphotic zones of the world's subtropical and tropical oligotrophic oceans, making them some of the most ecologically relevant photosynthetic microorganisms on Earth. The ecological success of these free-living phototrophs suggests that they are equipped with a regulatory system competent to address many different stress situations. However, Prochlorococcus genomes are compact and streamlined, with the majority encoding only five different sigma factors, five to six two-component systems and eight types of other transcriptional regulators.
View Article and Find Full Text PDFThe sRNA Yfr1 and members of the Yfr2 sRNA family are almost universally present within cyanobacteria. The conserved motifs of these sRNAs are nearly complementary to each other, suggesting their ability to participate in crosstalk. The conserved motif of Yfr1 is shared by members of the Yfr10 sRNA family, members of which are otherwise less conserved in sequence, structure, and synteny compared to Yfr1.
View Article and Find Full Text PDFPrior work has shown that popular peers can set a powerful norm for the valence and salience of aggression in adolescent classrooms, which enhances aggressive friendship processes (selection, maintenance, influence). It is unknown, however, whether popular peers also set a norm for prosocial behavior that can buffer against aggressive friendship processes and stimulate prosocial friendship processes. This study examined the role of prosocial and aggressive popularity norm combinations in prosocial and aggressive friendship processes.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
September 2019
The Harderian gland (HG) is an orbital structure whose proteinaceous secretions pass through the nasolacrimal duct to the vomeronasal organ (VNO). Though these three structures occur in many tetrapod vertebrates, the garter snake (Thamnophis sirtalis) is one of the few vertebrates in which the passage of the proteinaceous secretions have been experimentally shown. Secreted proteins from the HG may function as transporters for chemical signals to the VNO epithelium.
View Article and Find Full Text PDFThe aim of this study was to unravel the interrelatedness of friendship and help, and to examine the characteristics of friendship and help networks. The effects of mutual versus one-sided help relations on friendship initiation and maintenance, and vice versa, were examined. Friendship and help networks were analyzed (N = 953 students; 41 classrooms; M = 12.
View Article and Find Full Text PDFProchlorococcus is a marine picocyanobacterium with a streamlined genome that is adapted to different ecological niches in the oligotrophic oceans. There are currently >20 regulatory small RNAs (sRNAs) that have been identified in the model strain Prochlorococcus MED4. While most of these sRNAs are ecotype-specific, sRNA homologs of Yfr1 and of the Yfr2 family are widely found throughout the cyanobacterial phylum.
View Article and Find Full Text PDFThis study examined to what extent adolescents' and their friends' risk behaviors (i.e., delinquency and alcohol use) hinder or promote their academic achievement (grade point average [GPA]), and vice versa.
View Article and Find Full Text PDFThis study concerns peer selection and influence dynamics in early adolescents' friendships regarding academic achievement. Using longitudinal social network analysis (RSiena), both selection and influence processes were investigated for students' average grades and their cluster-specific grades (i.e.
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