Genetic loss of Faah compromises male fertility in mice

Marijuana is the most commonly used illicit drug. Although there is some indication that reproductive functions in males are impaired in chronic marijuana users, the genetic evidence and underlying causes remain largely unknown. Herein we show that genetic loss of Faah, which encodes fatty acid amide hydrolase (FAAH), results in elevated levels of anandamide, an endocannabinoid, in the male reproductive system, leading to compromised fertilizing capacity of sperm. This defect is rescued by superimposing deletion of cannabinoid receptor 1 (Cnr1). Retention of Faah(-/-) sperm on the egg zona pellucida provides evidence that the capacity of sperm to penetrate the zona barrier is hampered by elevated anandamide levels. Collectively, the results show that aberrant endocannabinoid signaling via CNR1 impairs normal sperm function. Besides unveiling a new regulatory mechanism of sperm function, this study has clinical significance in male fertility.     

Passive sexual transmission of human immunodeficiency virus type 1 variants and adaptation in new hosts

Human immunodeficiency virus type 1 (HIV-1) genetic diversity is a major obstacle for the design of a successful vaccine. Certain viral polymorphisms encode human leukocyte antigen (HLA)-associated immune escape, potentially overcoming limited vaccine protection. Although transmission of immune escape variants has been reported, the overall extent to which this phenomenon occurs in populations and the degree to which it contributes to HIV-1 viral evolution are unknown. Selection on the HIV-1 env gene at transmission favors neutralization-sensitive variants, but it is not known to what degree selection acts on the internal HIV-1 proteins to restrict or enhance the transmission of immune escape variants. Studies have suggested that HLA class I may determine susceptibility to HIV-1 infection, but a definitive role for HLA at transmission remains unproven. Comparing populations of acute seroconverters and chronically infected patients, we found no evidence of selection acting to restrict transmission of HIV-1 variants. We found that statistical associations previously reported in chronic infection between viral polymorphisms and HLA class I alleles are not present in acute infection, suggesting that the majority of viral polymorphisms in these patients are the result of transmission rather than de novo adaptation. Using four episodes of HIV-1 transmission in which the donors and recipients were both sampled very close to the time of infection we found that, despite a transmission bottleneck, genetic variants of HIV-1 infection are transmitted in a frequency-dependent manner. As HIV-1 infections are seeded by unique donor-adapted viral variants, each episode is a highly individual antigenic challenge. Host-specific, idiosyncratic HIV-1 antigenic diversity will seriously tax the efficacy of immunization based on consensus sequences.     

Structural and functional analyses of a glycoside hydrolase family 5 enzyme with an unexpected β-fucosidase activity

We present characterization of PbFucA, a family 5 glycoside hydrolase (GH5) from Prevotella bryantii B(1)4. While GH5 members typically are xylanases, PbFucA shows no activity toward xylan polysaccharides. A screen against a panel of p-nitrophenol coupled sugars identifies PbFucA as a β-D-fucosidase. We also present the 2.2 ? resolution structure of PbFucA and use structure-based mutational analysis to confirm the role of catalytically essential residues. A comparison of the active sites of PbFucA with those of family 5 and 51 glycosidases reveals that while the essential catalytic framework is identical between these enzymes, the steric contours of the respective active site clefts are distinct and likely account for substrate discrimination. Our results show that members of this cluster of orthologous group (COG) 5520 have β-D-fucosidase activities, despite showing an overall sequence and structural similarity to GH-5 xylanases.     

Osteopontin,inflammation and myogenesis: influencing regeneration,fibrosis and size of skeletal muscle

Osteopontin is a multifunctional matricellular protein that is expressed by many cell types. Through cell-matrix and cell-cell interactions the molecule elicits a number of responses from a broad range of target cells via its interaction with integrins and the hyaluronan receptor CD44. In many tissues osteopontin has been found to be involved in important physiological and pathological processes, including tissue repair, inflammation and fibrosis. Post-natal skeletal muscle is a highly differentiated and specialised tissue that retains a remarkable capacity for regeneration following injury. Regeneration of skeletal muscle requires the co-ordinated activity of inflammatory cells that infiltrate injured muscle and are responsible for initiating muscle fibre degeneration and phagocytosis of necrotic tissue, and muscle precursor cells that regenerate the injured muscle fibres. This review focuses on the current evidence that osteopontin plays multiple roles in skeletal muscle, with particular emphasis on its role in regeneration and fibrosis following injury, and in determining the severity of myopathic diseases such as Duchenne muscular dystrophy.     

Transport of Particles in Intestinal Mucus under Simulated Infant and Adult Physiological Conditions: Impact of Mucus Structure and Extracellular DNA

The final boundary between digested food and the cells that take up nutrients in the small intestine is a protective layer of mucus. In this work, the microstructural organization and permeability of the intestinal mucus have been determined under conditions simulating those of infant and adult human small intestines. As a model, we used the mucus from the proximal (jejunal) small intestines of piglets and adult pigs. Confocal microscopy of both unfixed and fixed mucosal tissue showed mucus lining the entire jejunal epithelium. The mucus contained DNA from shed epithelial cells at different stages of degradation, with higher amounts of DNA found in the adult pig. The pig mucus comprised a coherent network of mucin and DNA with higher viscosity than the more heterogeneous piglet mucus, which resulted in increased permeability of the latter to 500-nm and 1-µm latex beads. Multiple-particle tracking experiments revealed that diffusion of the probe particles was considerably enhanced after treating mucus with DNase. The fraction of diffusive 500-nm probe particles increased in the pig mucus from 0.6% to 64% and in the piglet mucus from ca. 30% to 77% after the treatment. This suggests that extracellular DNA can significantly contribute to the microrheology and barrier properties of the intestinal mucus layer. To our knowledge, this is the first time that the structure and permeability of the small intestinal mucus have been compared between different age groups and the contribution of extracellular DNA highlighted. The results help to define rules governing colloidal transport in the developing small intestine. These are required for engineering orally administered pharmaceutical preparations with improved delivery, as well as for fabricating novel foods with enhanced nutritional quality or for controlled calorie uptake.     

A Novel Method to Evaluate the Community Built Environment Using Photographs – Environmental Profile of a Community Health (EPOCH) Photo Neighbourhood Evaluation Tool

Background

Previous research has shown that environments with features that encourage walking are associated with increased physical activity. Existing methods to assess the built environment using geographical information systems (GIS) data, direct audit or large surveys of the residents face constraints, such as data availability and comparability, when used to study communities in countries in diverse parts of the world. The aim of this study was to develop a method to evaluate features of the built environment of communities using a standard set of photos. In this report we describe the method of photo collection, photo analysis instrument development and inter-rater reliability of the instrument.

Methods/Principal Findings

A minimum of 5 photos were taken per community in 86 communities in 5 countries according to a standard set of instructions from a designated central point of each community by researchers at each site. A standard pro forma derived from reviewing existing instruments to assess the built environment was developed and used to score the characteristics of each community. Photo sets from each community were assessed independently by three observers in the central research office according to the pro forma and the inter-rater reliability was compared by intra-class correlation (ICC). Overall 87% (53 of 60) items had an ICC of ≥0.70, 7% (4 of 60) had an ICC between 0.60 and 0.70 and 5% (3 of 60) items had an ICC ≤0.50.

Conclusions/Significance

Analysis of photos using a standardized protocol as described in this study offers a means to obtain reliable and reproducible information on the built environment in communities in very diverse locations around the world. The collection of the photographic data required minimal training and the analysis demonstrated high reliability for the majority of items of interest.     

Criteria for the crystallization of polysaccharides

The relationship between crystallization and the annealing process is well established in the synthetic polymer field. This relationship appears to have been somewhat neglected in studies on biopolymers. Results are presented to show the effect of both humidity and temperature in promoting structural changes in polysaccharide system. Three different polysaccharides have been used as examples of how crystallization may be speeded up by annealing at elevated temperatures.     

Effect of food attractants on appetite and growth rate of gilthead bream, Sparus aurata L.

Appetite and growth rate were measured in Sparus aurata fed ad-libitum a basal diet supplemented with either a synthetic mixture of chemicals based upon the analysis of Mylilus edulis , muscle extract, or newly hatched Artemia saline nauplii. These components were tested for their feeding attraction potency, and were added to the basal diet at three concentrations each; 5, 10 and 20 g kg^-1 dry diet.
Appetite, which was defined as ad-libitum food intake, was significantly affected by the type and concentration of attractant. When the basal diet was supplemented with 10 or 20 g kg^-1 of the synthetic Mytilus edulis muscle extract, it was associated with significantly higher appetite than the basal diet only or the basal diet supplemented with any level of newly hatched Artemia salina nauplii. On the other hand, relative growth rate under the same conditions did not completely conform to the results with appetite. The difference between appetite and growth rate as criteria for the evaluation of food attractants is discussed.