Functional characteristics of culturable bacterioplankton from marine and estuarine environments.

Information on the structure of bacterioplankton communities is continuously increasing, while knowledge of their metabolic capabilities remains limited. In this study, the metabolic capacity of bacterioplankton was investigated, as such information is necessary to fully understand carbon cycling and other biogeochemical processes. The diversity of dominant culturable chemoorganotrophic bacteria from one estuarine and three marine environments was analyzed by random isolation of colony-forming units on solid media, taxonomical identification by partial 16S rRNA gene sequence analysis, and functional characterization of the isolates. A total of 76 16S rRNA gene sequences, representing 19 different genotypes, were obtained from the four sampling localities, including Bacillus, Pseudomonas, Pseudoalteromonas, Vibrio, and Erythrobacter as the most frequently isolated genera. The range of metabolic functions possessed by the cultured bacterial assemblages differed significantly between sites. Similarly, the percentage at each sampling station of bacteria capable of performing a specific function was significantly different for 18 of the 25 investigated metabolic functions. At two localities, the bacterial assemblages were dominated by a single genus (Pseudoalteromonas or Erythrobacter) and appeared to be functionally specialized. More than 95% of the isolates were capable of utilizing dissolved free amino acids and protein as their sole nitrogen sources, and all isolates of the specialized assemblages expressed beta-glucosidase. Furthermore, only some of the isolates were able to utilize NH4+, while up to two thirds of the isolates of the two marine sites were able to grow on NO3-.     

Physiological girdling of pine trees via phloem chilling: proof of concept

Quantifying below-ground carbon (C) allocation is particularly difficult as methods usually disturb the root-mycorrhizal-soil continuum. We reduced C allocation below ground of loblolly pine trees by: (1) physically girdling trees and (2) physiologically girdling pine trees by chilling the phloem. Chilling reduced cambium temperatures by approximately 18 degrees C. Both methods rapidly reduced soil CO2 efflux, and after approximately 10 days decreased net photosynthesis (P(n)), the latter indicating feedback inhibition. Chilling decreased soil-soluble C, indicating that decreased soil CO2 efflux may have been mediated by a decrease in root C exudation that was rapidly respired by microbes. These effects were only observed in late summer/early autumn when above-ground growth was minimal, and not in the spring when above-ground growth was rapid. All of the effects were rapidly reversed when chilling was ceased. In fertilized plots, both chilling and physical girdling methods reduced soil CO2 efflux by approximately 8%. Physical girdling reduced soil CO2 efflux by 26% in non-fertilized plots. This work demonstrates that phloem chilling provides a non-destructive alternative to reducing the movement of recent photosynthate below the point of chilling to estimate C allocation below ground on large trees.     

Is Helicobacter pylori the cause of dyspepsia?

OBJECTIVE--To determine the association between infection with Helicobacter pylori and dyspepsia. DESIGN--Cross sectional study of dyspeptic subjects and age and sex matched controls identified by a questionnaire survey of all inhabitants aged 20-69. (Endoscopy, histological examination, and microbiological examinations of biopsies from the gastric mucosa were performed blind.) SETTING--Population based survey in Sørreisa, Norway. SUBJECTS--All 782 dyspeptic subjects (excluding those with a previous history of peptic ulcer, gall stones or kidney stones, and coronary heart disease) and controls were offered an endoscopy, of whom 309 dyspeptic subjects and 310 controls attended. MAIN OUTCOME MEASURES--Prevalences of endoscopic and histological diagnoses and of cultures positive for H pylori. RESULTS--A high prevalence of positive cultures, increasing with age, was found in both dyspeptic subjects (48%) and non-dyspeptic controls (36%) (p = 0.004). Positive cultures in both dyspeptic subjects and controls were strongly associated with histological gastritis (70%, 95% confidence interval 65.5 to 85.3; 60%, 52.7 to 67.7, respectively) and peptic ulcer (92%, 61.5 to 99.8; 64.1, 9.4 to 99.2, respectively). Only 3% of subjects with a histologically non-inflamed gastric mucosa had this infection (dyspeptic subjects 2%, 0.2 to 7.0; controls 4%; 1.2 to 8.8). CONCLUSIONS--The relation between dyspeptic symptoms and H pylori is dubious; H pylori seems to have a pathogenetic role in gastritis and may be a contributing factor but not a cause of peptic ulcer.     

Functional activity of RLIM/Rnf12 is regulated by phosphorylation-dependent nucleocytoplasmic shuttling

The X-linked gene Rnf12 encodes the ubiquitin ligase really interesting new gene (RING) finger LIM domain–interacting protein (RLIM)/RING finger protein 12 (Rnf12), which serves as a major sex-specific epigenetic regulator of female mouse nurturing tissues. Early during embryogenesis, RLIM/Rnf12 expressed from the maternal allele is crucial for the development of extraembryonic trophoblast cells. In contrast, in mammary glands of pregnant and lactating adult females RLIM/Rnf12 expressed from the paternal allele functions as a critical survival factor for milk-producing alveolar cells. Although RLIM/Rnf12 is detected mostly in the nucleus, little is known about how and in which cellular compartment(s) RLIM/Rnf12 mediates its biological functions. Here we demonstrate that RLIM/Rnf12 protein shuttles between nucleus and cytoplasm and this is regulated by phosphorylation of serine S214 located within its nuclear localization sequence. We show that shuttling is important for RLIM to exert its biological functions, as alveolar cell survival activity is inhibited in cells expressing shuttling-deficient nuclear or cytoplasmic RLIM/Rnf12. Thus regulated nucleocytoplasmic shuttling of RLIM/Rnf12 coordinates cellular compartments during mammary alveolar cell survival.     

Contrasting Patterns of Genetic Differentiation among Blackcaps (Sylvia atricapilla) with Divergent Migratory Orientations in Europe

Migratory divides are thought to facilitate behavioral, ecological, and genetic divergence among populations with different migratory routes. However, it is currently contentious how much genetic divergence is needed to maintain distinct migratory behavior across migratory divides. Here we investigate patterns of neutral genetic differentiation among Blackcap (Sylvia atricapilla) populations with different migratory strategies across Europe. We compare the level of genetic divergence of populations migrating to southwestern (SW) or southeastern (SE) wintering areas with birds wintering in the British Isles following a recently established northwesterly (NW) migration route. The migratory divide between SW and SE wintering areas can be interpreted as a result of a re-colonization process after the last glaciation. Thus we predicted greater levels of genetic differentiation among the SW/SE populations. However, a lack of genetic differentiation was found between SW and SE populations, suggesting that interbreeding likely occurs among Blackcaps with different migratory orientations across a large area; therefore the SW/SE migratory divide can be seen as diffuse, broad band and is, at best, a weak isolating barrier. Conversely, weak, albeit significant genetic differentiation was evident between NW and SW migrants breeding sympatrically in southern Germany, suggesting a stronger isolating mechanism may be acting in this population. Populations located within/near the SW/SE contact zone were the least genetically divergent from NW migrants, confirming NW migrants likely originated from within the contact zone. Significant isolation-by-distance was found among eastern Blackcap populations (i.e. SE migrants), but not among western populations (i.e. NW and SW migrants), revealing different patterns of genetic divergence among Blackcap populations in Europe. We discuss possible explanations for the genetic structure of European Blackcaps and how gene flow influences the persistence of divergent migratory behaviors.     

A Systematic Review of MicroRNA in Glioblastoma Multiforme: Micro-modulators in the Mesenchymal Mode of Migration and Invasion

Glioblastoma multiforme (GBM) is an incurable form of brain cancer with a very poor prognosis. Because of its highly invasive nature, it is impossible to remove all tumor cells during surgical resection, making relapse inevitable. Further research into the regulatory mechanism underpinning GBM pathogenesis is therefore warranted, and over the past decade, there has been an increased focus on the functional role of microRNA (miRNA). This systematic review aims to present a comprehensive overview of all the available literature on the expression profiles and function of miRNA in GBM. Here, we have reviewed 163 papers and identified 253 upregulated, 95 downregulated, and 17 disputed miRNAs with respect to expression levels; 85 % of these miRNAs have not yet been functionally characterized. A focus in this study has been 26 interesting miRNAs involved in the mesenchymal mode of migration and invasion, demonstrating the importance of miRNAs in the context of the cellular niche. Both oncogenic and tumor-suppressive miRNAs were found to affect target genes involved in cell migration, cytoskeletal rearrangement, invasiveness, and angiogenesis. Clearly, the distinct functional properties of these miRNAs need further investigation and might hold a great potential in future molecular therapies targeting GBM.     

The old trout Salmo trutta in the pond

The last of 12 brown trout Salmo trutta stocked in a small pond in south‐east Norway in 1979 were caught in July 2011. These fish represent a curiosity regarding longevity and growth pattern, and ageing from otoliths was consistent with the known life history of this specimen. Despite almost total stagnation in growth since the age of 16 years, the testes were fully developed.     

FEMALE PROMISCUITY IS POSITIVELY ASSOCIATED WITH NEUTRAL AND SELECTED GENETIC DIVERSITY IN PASSERINE BIRDS

Passerine birds show large interspecific variation in extrapair paternity rates. There is accumulating evidence that such promiscuous behavior is driven by indirect, genetic benefits to females. Sexual selection theory distinguishes between two types of genetic benefits, additive and nonadditive effects, mediated by preferences for good and compatible genes, respectively. Good genes preferences should imply directional selection and mating skew among males, and thus reduced genetic diversity in the population. In contrast, compatible genes preferences should give balancing selection that retains genetic diversity. Here, we test how well these predictions fit with patterns of variation in genetic diversity and promiscuity levels among passerine birds. We found that more promiscuous species had higher nucleotide diversity at autosomal introns, but not at Z‐chromosome introns. We also found that major histocompatibility complex (MHC) class IIB alleles had higher sequence diversity, and therefore should recognize a broader spectrum of pathogens, in more promiscuous species. Our results suggest that female promiscuity targets a multitude of autosomal genes for their nonadditive, compatibility benefits. Also, as immunity genes seem to be of particular importance, we hypothesize that interspecific variation in female promiscuity among passerine birds has arisen in response to the strength of pathogen‐mediated selection.