The PM2 virion has a novel organization with an internal membrane and pentameric receptor binding spikes

Biological membranes are notoriously resistant to structural analysis. Excellent candidates to tackle this problem in situ are membrane-containing viruses where the membrane is constrained by an icosahedral capsid. Cryo-EM and image reconstruction of bacteriophage PM2 revealed a membrane bilayer following the internal surface of the capsid. The viral genome closely interacts with the inner leaflet. The capsid, at a resolution of 8.4 A, reveals 200 trimeric capsomers with a pseudo T = 21 dextro organization. Pentameric receptor-binding spikes protrude from the surface. It is evident from the structure that the PM2 membrane has at least two important roles in the life cycle. First, it acts as a scaffold to nucleate capsid assembly. Second, after host recognition, it fuses with the host outer membrane to promote genome entry. The structure also sheds light on how the viral supercoiled circular double-stranded DNA genome might be packaged and released.     

Sequence and Gene Expression Analyses of Plasmid pHPM8 from Helicobacter pylori Reveal the Presence of Two Operons with Putative Roles in Plasmid Replication and Antibiotic Activity

The DNA sequence of a 7.8-kb Helicobacter pylori plasmid, pHPM8, was determined. Six open reading frames (ORFs) were present. Ribonuclease protection studies showed that ORF1/ORF2 and ORF3/ORF4 genes are organized in operons possibly involved in plasmid replication and in production of a peptide with antibiotic activity, respectively. Finding areas of pHPM8 with a high level of identity to H. pylori chromosomal DNA supported the hypothesis that recombination occurs between plasmids and the chromosome of H. pylori.     

LIMaS: the JAVA-based application and database for microarray experiment tracking

Microarrays allow monitoring of gene expression for tens of thousands of genes in parallel and are being used routinely to generate huge amounts of valuable data. Handling and analysis of such data are becoming major bottlenecks in the utilization of the technology. To enable the researcher to interpret the results postanalysis, we have developed a laboratory information management system for microarrays (LIMaS) with an n-tier Java front-end and relational database to record and manage large-scale expression data preanalysis. This system enables the laboratory to replace the paper trail with an efficient and fully customizable interface giving it the ability to adapt to any working practice, e.g., handling many resources used to form many products (chaining of resources). The ability to define sets of activities, resources, and workflows makes LIMaS MIAME-supportive.LIMaS is available for download at (http://www.mgu.har.mrc.ac.uk/microarray.)     

Knock-Down of IL-1Ra in Obese Mice Decreases Liver Inflammation and Improves Insulin Sensitivity

Interleukin 1 Receptor antagonist (IL-1Ra) is highly elevated in obesity and is widely recognized as an anti-inflammatory cytokine. While the anti-inflammatory role of IL-1Ra in the pancreas is well established, the role of IL-1Ra in other insulin target tissues and the contribution of systemic IL-1Ra levels to the development of insulin resistance remains to be defined. Using antisense knock down of IL-1Ra in vivo, we show that normalization of IL-1Ra improved insulin sensitivity due to decreased inflammation in the liver and improved hepatic insulin sensitivity and these effects were independent of changes in body weight. A similar effect was observed in IL1-R1 KO mice, suggesting that at high concentrations of IL-1Ra typically observed in obesity, IL-1Ra can contribute to the development of insulin resistance in a mechanism independent of IL-1Ra binding to IL-1R1. These results demonstrate that normalization of plasma IL-1Ra concentration improves insulin sensitivity in diet- induced obese mice.     

Leveraging remote learning during the Covid‐19 pandemic to enhance student understanding of biodiversity

We evaluated whether individual nature‐based ecological (NBE) study used in tandem with group collaboration enhanced undergraduate student understanding of ecological concepts and pro‐environmental perceptions. In response to the Covid‐19 pandemic, we developed a multiweek unit on the latitude diversity gradient (LDG) for fully online instruction that leveraged the unique situation of students learning in disparate geographic locations. Student understanding of the LDG and pro‐environmental perceptions were assessed with surveys administered both pre‐ and post‐activity in an introductory‐level biology laboratory course. Student understanding of the geographic location where biodiversity is the highest was high prior to the start of the laboratory unit and exhibited only a small improvement after the unit. In contrast, students’ higher order thinking around the LDG was enhanced by the lab activity. Student environmental perceptions shifted toward ecocentric views and away from anthropocentric views after the laboratory unit. The greatest gains in ecological understanding and shifts toward ecocentric viewpoints occurred in the group of students who visited their field sites most often. Our results provide further evidence as to the value of NBE for the introductory biology laboratory, even in an online learning setting. The lab unit described in this study provides a potential approach to teaching ecology in an online format that could easily be adapted to fit the needs of a particular curriculum.     

Vitamin D and maternal and child health: Overview and implications for dietary requirements

The essentiality of vitamin D for normal growth and development has been recognized for over 80 years, and vitamin D fortification programs have been in place in the United States for more than 70 years. Despite the above, vitamin D deficiency continues to be a common finding in certain population groups. Vitamin D deficiency has been suggested as a potential risk factor for the development of preeclampsia, and vitamin D deficiency during infancy and early childhood is associated with an increased risk for numerous skeletal disorders, as well as immunological and vascular abnormalities. Vitamin D deficiency can occur through multiple mechanisms including the consumption of diets low in this vitamin and inadequate exposure to environmental ultraviolet B rays. The potential value of vitamin D supplementation in high‐risk pregnancies and during infancy and early childhood is discussed. Currently, there is vigorous debate concerning what constitutes appropriate vitamin D intakes during early development as exemplified by differing recommendations from the Institute of Medicine Dietary Reference Intake report and recent recommendations by the Endocrine Society. As is discussed, a major issue that needs to be resolved is what key biological endpoint should be used when making vitamin D recommendations for the pregnant woman and her offspring. Birth Defects Research (Part C) 99:24–44, 2013. © 2013 Wiley Periodicals, Inc.     

Turbidity Structures the Controls of Ecosystem Metabolism and Associated Metabolic Process Domains Along a 75-km Segment of a Semiarid Stream

Ecosystems - Stream ecosystem metabolism contributes to global carbon cycling, yet predicting metabolism across ecosystems remains elusive. Even within stream segments, spatial variation in...     

Genetic diseases of the Kennedy pathways for membrane synthesis

The two branches of the Kennedy pathways (CDP-choline and CDP-ethanolamine) are the predominant pathways responsible for the synthesis of the most abundant phospholipids, phosphatidylcholine and phosphatidylethanolamine, respectively, in mammalian membranes. Recently, hereditary diseases associated with single gene mutations in the Kennedy pathways have been identified. Interestingly, genetic diseases within the same pathway vary greatly, ranging from muscular dystrophy to spastic paraplegia to a childhood blinding disorder to bone deformations. Indeed, different point mutations in the same gene (PCYT1; CCTα) result in at least three distinct diseases. In this review, we will summarize and review the genetic diseases associated with mutations in genes of the Kennedy pathway for phospholipid synthesis. These single-gene disorders provide insight, indeed direct genotype-phenotype relationships, into the biological functions of specific enzymes of the Kennedy pathway. We discuss potential mechanisms of how mutations within the same pathway can cause disparate disease.