Mycosporine glutamine and related mycosporines in the fungus Pyronema omphalodes

The structure of mycosporine glutamine, a new compound, has been established and its presence demonstrated in two fungi Pyronema omphalodes and Glomerella cingulata. Mycosporine glutamic acid has been isolated from Helvella leucomelaneae. Co-occurrence of normycosporine glutamine, mycosporine glutamine and glucosylmycosporine glutaminol has been demonstrated in the fungus P. omphalodes. A biosynthetic pathway is proposed. Mycosporines have been compared by HPLC.     

WLIP, a lipodepsipeptide of Pseudomonas 'reactans', as inhibitor of the symptoms of the brown blotch disease of Agaricus bisporus

A cell-free crude extract containing the white line inducing principle (WLIP), a lipodepsipeptide produced by Pseudomonas 'reactans' , could inhibit browning of mushrooms caused by Pseudomonas tolaasii . Mushrooms inoculated with Ps. tolaasii at concentrations of 2·7 × 10⁶ cfu ml⁻¹ or higher showed the symptoms of the disease after 2 d of incubation. Mushroom caps treated with various concentrations of a crude WLIP preparation, and later inoculated with bacterial concentrations higher than the threshold value, did not develop the symptoms of the disease. One milligram of a crude WLIP preparation could block 50% of the symptoms caused by 1·2 × 10⁷ cfu. The inhibition of browning was effective when incubating at low temperatures for 4 d. A suspension containing 1·6 mg ml⁻¹ of pure WLIP was also able to inhibit the symptoms of brown blotch disease induced by 7·6 × 10⁶ cfu ml⁻¹ of Ps. tolaasii .     

Emerging role for ERM proteins in cell adhesion and migration

The highly related ERM (Ezrin, Radixin, Moesin) proteins provide a regulated linkage between the membrane and the underlying actin cytoskeleton. They also provide a platform for the transmission of signals in responses to extracellular cues. Studies in different model organisms and in cultured cells have highlighted the importance of ERM proteins in the generation and maintenance of specific domains of the plasma membrane. A central question is how do ERM proteins coordinate actin filament organization and membrane protein transport/stability with signal transduction pathways to build up complex structures? Through their interaction with numerous partners including membrane proteins, actin cytoskeleton and signaling molecules, ERM proteins have the ability to organize multiprotein complexes in specific cellular compartments. Likewise, ERM proteins participate in diverse functions including cell morphogenesis, endocytosis/exocytosis, adhesion and migration. This review focuses on aspects still poorly understood related to the function of ERM proteins in epithelial cell adhesion and migration.Key words: epithelial cells, membrane-cytoskeleton interface, morphogenesis, ERM proteins, cell adhesion     

Risk of Early-Onset Neonatal Infection with Maternal Infection or Colonization: A Global Systematic Review and Meta-Analysis

Background

Neonatal infections cause a significant proportion of deaths in the first week of life, yet little is known about risk factors and pathways of transmission for early-onset neonatal sepsis globally. We aimed to estimate the risk of neonatal infection (excluding sexually transmitted diseases [STDs] or congenital infections) in the first seven days of life among newborns of mothers with bacterial infection or colonization during the intrapartum period.

Methods and Findings

We searched PubMed, Embase, Scopus, Web of Science, Cochrane Library, and the World Health Organization Regional Databases for studies of maternal infection, vertical transmission, and neonatal infection published from January 1, 1960 to March 30, 2013. Studies were included that reported effect measures on the risk of neonatal infection among newborns exposed to maternal infection. Random effects meta-analyses were used to pool data and calculate the odds ratio estimates of risk of infection. Eighty-three studies met the inclusion criteria. Seven studies (8.4%) were from high neonatal mortality settings. Considerable heterogeneity existed between studies given the various definitions of laboratory-confirmed and clinical signs of infection, as well as for colonization and risk factors. The odds ratio for neonatal lab-confirmed infection among newborns of mothers with lab-confirmed infection was 6.6 (95% CI 3.9–11.2). Newborns of mothers with colonization had a 9.4 (95% CI 3.1–28.5) times higher odds of lab-confirmed infection than newborns of non-colonized mothers. Newborns of mothers with risk factors for infection (defined as prelabour rupture of membranes [PROM], preterm <37 weeks PROM, and prolonged ROM) had a 2.3 (95% CI 1.0–5.4) times higher odds of infection than newborns of mothers without risk factors.

Conclusions

Neonatal infection in the first week of life is associated with maternal infection and colonization. High-quality studies, particularly from settings with high neonatal mortality, are needed to determine whether targeting treatment of maternal infections or colonization, and/or prophylactic antibiotic treatment of newborns of high risk mothers, may prevent a significant proportion of early-onset neonatal sepsis. Please see later in the article for the Editors'' Summary     

Na(+)/H(+) exchanger 3 is in large complexes in the center of the apical surface of proximal tubule-derived OK cells

Cell biological approaches were usedto examine the location and function of the brush border (BB)Na⁺/H⁺ exchanger NHE3 in the opossum kidney(OK) polarized renal proximal tubule cell line. NHE3 epitope taggedwith the vesicular stomatitis virus glycoprotein epitope(NHE3V) was stably expressed and called OK-E3V cells. On thebasis of cell surface biotinylation studies, these cells had10-15% of total NHE3 on the BB. Intracellular NHE3V largelycolocalized with Rab11 and to a lesser extent with EEA1. The BBlocation of NHE3V was examined by confocal microscopy relative to thelectins wheat germ aggluttinin (WGA) and phytohemagluttin E (PHA-E), aswell as the B subunit of cholera toxin (CTB). The cells were pyramidal,and NHE3 was located in microvilli in the center of the apical surface.In contrast, PHA-E, WGA, and CTB were diffusely distributed on the BB.Detergent extraction showed that total NHE3V was largely soluble inTriton X-100, whereas virtually all surface NHE3V was insoluble.Sucrose density gradient centrifugation demonstrated that total NHE3Vmigrated at the same size as ~400- and ~900-kDa standards, whereassurface NHE3V was enriched in the ~900-kDa form. Under basalconditions, NHE3 cycled between the cell surface and the recyclingpathway through a phosphatidylinositol (PI) 3-kinase-dependentmechanism. Measurements of surface and intracellular pH were obtainedby using FITC-WGA. Internalization of FITC-WGA occurred largely intothe juxtanuclear compartment that contained Rab11 and NHE3V. pH valueson the apical surface and in endosomes in the presence of the NHE3blocker, S3226, were elevated, showing that NHE3 functioned to acidifyboth compartments. In conclusion, NHE3V in OK cells exists in distinctdomains both in the center of the apical surface and in a juxtanuclearcompartment. In the BB fraction, NHE3 is largely in thedetergent-insoluble fraction in lipid rafts and/or in largeheterogenous complexes ranging from ~400 to ~900 kDa.

     

Absolute configuration of aleuriaxanthin

The chirality of aleuriaxanthin ex Aleuria aurantia has been shown to be 2′R by means of the modified Horeau method. Other carotenoids with terminal methylene in an acylic end group were not detected in A. aurantia.     

Ezrin interacts with focal adhesion kinase and induces its activation independently of cell-matrix adhesion

Ezrin, a membrane-cytoskeleton linker, is required for cell morphogenesis, motility, and survival through molecular mechanisms that remain to be elucidated. Using the N-terminal domain of ezrin as a bait, we found that p125 focal adhesion kinase (FAK) interacts with ezrin. We show that the two proteins coimmunoprecipitate from cultured cell lysates. However, FAK does not interact with full-length ezrin in vitro, indicating that the FAK binding site on ezrin is cryptic. Mapping experiments showed that the entire N-terminal domain of FAK (amino acids 1-376) is required for optimal ezrin binding. While investigating the role of the ezrin-FAK interaction, we observed that, in suspended kidney-derived epithelial LLC-PK1 cells, overproduction of ezrin promoted phosphorylation of FAK Tyr-397, the major autophosphorylation site, creating a docking site for FAK signaling partners. Treatment of the cells with a Src family kinase inhibitor reduced the phosphorylation of Tyr-577 but not that of Tyr-397, indicating that ezrin-mediated FAK activation does not require the activity of Src kinases. Altogether, these observations indicate that ezrin is able to trigger FAK activation in signaling events that are not elicited by cell-matrix adhesion.     

Bias and Sampling Error of the Estimated Proportion of Genotypic Variance Explained by Quantitative Trait Loci Determined From Experimental Data in Maize Using Cross Validation and Validation With Independent Samples.

Cross validation (CV) was used to analyze the effects of different environments and different genotypic samples on estimates of the proportion of genotypic variance explained by QTL (p). Testcrosses of 344 F(3) maize lines grown in four environments were evaluated for a number of agronomic traits. In each of 200 replicated CV runs, this data set was subdivided into an estimation set (ES) and various test sets (TS). ES were used to map QTL and estimate p for each run (p(ES)) and its median (p(ES)) across all runs. The bias of these estimates was assessed by comparison with the median (p(TS.ES)) obtained from TS. We also used two independent validation samples derived from the same cross for further comparison. The median p(ES) showed a large upward bias compared to p(TS.ES). Environmental sampling generally had a smaller effect on the bias of p(ES) than genotypic sampling or both factors simultaneously. In independent validation, p(TS.ES) was on average only 50% of p(ES). A wide range among p(ES) reflected a large sampling error of these estimates. QTL frequency distributions and comparison of estimated QTL effects indicated a low precision of QTL localization and an upward bias in the absolute values of estimated QTL effects from ES. CV with data from three QTL studies reported in the literature yielded similar results as those obtained with maize testcrosses. We therefore recommend CV for obtaining asymptotically unbiased estimates of p and consequently a realistic assessment of the prospects of MAS.