microPublication biology最新文献

[This corrects the article DOI: 10.17912/micropub.biology.001394.].

The discovery of Wza, an octomeric helical barrel integral bacterial outer-transmembrane protein, has challenged the widely held understanding that all integral outer-membrane proteins of Gram-negative bacteria are closed β-barrels composed of transmembrane β- strands. Wza is a member of the Outer-Membrane Polysaccharide Exporter family and our bioinformatics analysis suggests that other members of the family may also contain outer-membrane transmembrane segments that are helical. A review of the literature indicates that in addition to Wza, outer-membrane core complex proteins of the type IV secretion systems also contain transmembrane segments that are helical.

Lysosome activity regulates germline development in multiple species. In the Drosophila testis, lysosomes activate as germ cells exit mitosis and enter meiosis. Notably, reduced activity of germ-cell lysosomes, which is seen during aging, leads to fewer viable sperm. Here, we investigated the activity of Mitf/TFEB, a master regulator of lysosome biogenesis, during Drosophila spermatogenesis. We discovered that Mitf activity was upregulated in meiotic-stage spermatocytes, consistent with the lysosome-activation pattern. However, Mitf activity in spermatocytes declined in older males, concurrent with reduced expression of a Mitf-targeted V-ATPase component. These findings provide insight into the regulation of upstream lysosome controls during spermatogenesis.

Three novel temperate siphoviruses, Juno112, KHumphrey, and ChuckDuck, were isolated from soil at Stevenson University using the bacterium Arthrobacter globiformis B-2979. Based on gene content similarity, Juno112 and KHumphrey are assigned to actinobacteriophage cluster AS3 and ChuckDuck to cluster FA. All three phages encode tyrosine recombinases, with ChuckDuck encoding two.

Gibberellic acid (GA) is a phytohormone that is important for plant growth and development. Mutants in GA biosynthesis, signaling and metabolism have been critical to understanding the role GA plays in plants. GA mutants have also revolutionized global production of staple crops such as rice, wheat, and barley. GA mutants have been isolated in maize and characterization of the underlying genes has helped map the GA biosynthesis and signaling pathways. However, the number of maize dwarf mutants is far less than other species. Here, we identify new dwarf mutants that could benefit our understanding of maize plant height control.

The identification and characterization of gene paralogs is crucial to understand the functional contribution of individual genes/proteins to biological pathways. Here, we have identified 51 genes belonging to fifteen paralogous groups encoding enzymes involved in carbohydrate metabolism in Drosophila melanogaster . Strikingly, most paralogous groups comprise a single 'canonical' enzyme that is expressed ubiquitously and one or more variants expressed predominantly in the testis. Most of these testis-specific forms are predicted to be catalytically inactive, suggesting they may have adopted regulatory roles. This work will aid the planning and interpretation of experimental studies of several Drosophila metabolic pathways, including glycolysis, gluconeogenesis and the pentose phosphate pathway.

BCG greatly stimulates innate immune cells. Previous studies demonstrated that BCG-stimulated monocytes develop trained immunity whereby they respond to homologous and heterologous antigens. Previous studies used isolated monocytes or animal models to study BCG-induced trained immunity, which have benefits and limitations. To approximate in vivo conditions, we stimulated peripheral blood mononuclear cells (PBMCs) with BCG-treated human fibroblasts. We found that compared with BCG stimulation, the addition of fibroblasts increased the expression of IFN-γ in NK and γδ T cells and of TNF-α and IL-10 in monocytes. We conclude that BCG-treated fibroblasts offer advantages over BCG alone for studying trained immunity.

Nutrient availability influences ribosome biogenesis, requiring dynamic regulation of RNA Pol I activity. In C. elegans , fasting reduces pre-rRNA levels. However, whether this reduction stems from a regulation of RNA Pol I expression remains unclear. Here, we examined how the nutritional status affects the localization and expression levels of RPOA-2 , a core subunit of RNA Pol I, in the intestine. We found that RPOA-2 retains its nucleolar localization regardless of animals being fed, fasted or fed after fasting. Interestingly, fasting reduces RPOA-2 protein amounts which are restored upon feeding. These findings suggest that the availability of RNA Pol I core subunits contributes to the regulation of rDNA transcription in response to nutrients.

The recent construction of a parthenogenetic strain of D. melanogaster offers new avenues of research, but this potential is limited by the stock's abysmal fecundity. We tried using spermless (placebo) males to "trick" the virgins into producing more offspring, but the boost that we achieved proved to be short-lived due to premature death of the mothers. To explore the cause of this mortality, we compared the lifespans of parthenogenetic vs. wild-type females when mated with spermless males. We found that parthenogenetic females are less robust than wild-females when raised alone but are more resistant to harm from spermless males.

The C. elegans transcription factor NHR-49 has been extensively studied for its functions in regulating metabolic processes, stress responses, innate immunity and aging. Molecular identification of a gene previously known as bah-3 , which affects susceptibility of worms to deleterious surface attachment of bacterial biofilms from Yersinia spp., revealed that bah-3 ( dc9 ) is an ochre nonsense allele of nhr-49 . Other severe mutations of nhr-49 also had a Bah phenotype, but deletions affecting 5' isoforms of the gene did not affect biofilm attachment, nor did 3' gain-of-function missense mutations. Other bah genes ( bah-1 , bah-2 , bah-4 ) encode GT92 glycosylation factors, predicted to affect surface coat. NHR-49 may act as a positive transcription factor for one or more of these surface glycosylation genes, in contrast to its other roles in regulating metabolic processes.