Desmosomal adhesion: structural basis,molecular mechanism and regulation (Review)

Desmosomes are adhesive intercellular junctions of epithelia and cardiac muscle. They have an essential function in maintaining the integrity of tissues, which is compromised in human genetic and autoimmune disease that targets desmosomal components. Recent evidence (1) suggests new roles for the function of desmosomal adhesion in tissue morphogenesis, (2) gives new insights into the molecular mechanism of adhesion, (3) indicates that the desmosomal adhesion molecules, desmocollin and desmoglein, may contribute to the regulation of epidermal diffentiation, and (4) shows that the affinity of desmosomal adhesion is regulated by protein kinase C.     

Klinische,pathologisch-anatomische,thermographische und radiologische Befunde bei einer Giraffe mit chronischer Arthritis

Chronic arthritis is a known medical problem in many species also in artiodactyla. The moist coldness that exists in the latitudes of Germany enhances this condition in animals that are accustomed to dry coldness in their natural habitats. This case report shows that thermography can be used for the assessment of arthritis in giraffes. Post-mortem results of pathology and computed tomography confirm the diagnosis based on thermography. Thermal imaging is a practical, non-invasive diagnostic tool for examining animals without stress and anesthesia.     

A rapid (one day), sensitive real-time polymerase chain reaction assay for detecting Escherichia coli O157:H7 in ground beef

The purpose of this study was to apply our rapid, integrated double enrichment 5' nuclease real-time polymerase chain reaction assay for the detection of Escherichia coli O157:H7 and evaluate its efficacy. The assay targeted ground beef, an important vehicle in disease epidemiology. The assay reliably determined in 8 h the presence of E. coli O157:H7 in ground beef at the level of 1 colony-forming unit (CFU)/g. The sensitivity and specificity of the assay were compared with that of standard enrichment diagnostic techniques. A correlation of 100% in detection was achieved to the limit of 1 CFU/g. This assay can be used as a rapid, automatic process for identification of E. coli O157:H7 in ground beef or can be integrated with standard culture procedures, resulting in considerable cost and time savings.     

Plant Chitinases: Genetic Diversity and Physiological Roles

Chitinase proteins are widely distributed across diverse biological systems. Chitinases hydrolyze chitin, chitosan, lipochitooligosaccharides, peptidoglycan, arabinogalactan and glycoproteins containing N-acetylglucosamine. Analyses of genome-wide sequence and microarray expression profilings show that chitinase genes are represented by large families and the individual member genes are expressed in diverse conditions. Chitinase proteins are members in the group of the pathogenesis-related proteins that are strongly induced when host plant cells are challenged by pathogen stress and thus chitinases constitute an important arsenal of plants against fungal pathogens. Transgenic plants have been produced that overexpress chitinases alone or in conjunction with other defense-related proteins. The phenotype analyses of such plants have shown enhanced disease resistance in large number of cases. Apart from defense against pathogen stress, chitinases are implicated in relationships between plant cells and fungi (e.g., mycorrhizae associations) and bacteria (e.g., legume/Rhizobium associations). Chitinases are also involved in plant abiotic stress responses as noted for osmotic, salt, cold, wounding and heavy metal stresses. Chitinases play a role in developmental aspects of plants too (i.e., regulation of plant embryogenesis process). A detailed account of the genetic diversity and functional aspects of plant chitinases is presented in this review.     

Supported employment: cost-effectiveness across six European sites

A high proportion of people with severe mental health problems are unemployed but would like to work. Individual Placement and Support (IPS) offers a promising approach to establishing people in paid employment. In a randomized controlled trial across six European countries, we investigated the economic case for IPS for people with severe mental health problems compared to standard vocational rehabilitation. Individuals (n=312) were randomized to receive either IPS or standard vocational services and followed for 18 months. Service use and outcome data were collected. Cost‐effectiveness analysis was conducted with two primary outcomes: additional days worked in competitive settings and additional percentage of individuals who worked at least 1 day. Analyses distinguished country effects. A partial cost‐benefit analysis was also conducted. IPS produced better outcomes than alternative vocational services at lower cost overall to the health and social care systems. This pattern also held in disaggregated analyses for five of the six European sites. The inclusion of imputed values for missing cost data supported these findings. IPS would be viewed as more cost‐effective than standard vocational services. Further analysis demonstrated cost‐benefit arguments for IPS. Compared to standard vocational rehabilitation services, IPS is, therefore, probably cost‐saving and almost certainly more cost‐effective as a way to help people with severe mental health problems into competitive employment.     

Monitoring training load in youth soccer players: effects of a six-week preparatory training program and the association between external and internal loads

This study examined the effects of a six-week preparatory training program on physical performance and physiological adaptations in junior soccer players. Additionally, we investigated whether a relationship existed between external and internal loads. Youth soccer players (aged 16 years old) from a youth football academy participated in six weeks of pre-conditioning training. Wireless Polar Team Pro and Polar heart rate sensors (H10) were used to monitor physical performance indicators (sprint and acceleration scores, covered distance, maximum and average speed and duration), physiological responses (maximum and average heart rate [HR] and R-R interval, time in HR zones 4+5, and heart rate variability [HRV]), and training load score. Additionally, muscle status and rating of perceived exertion (RPE) scores were measured using digital questionnaires. Significant increases were observed in the majority of physical performance indicators [i.e., sprints (p = 0.015, ES = 1.02), acceleration (p = 0.014, ES = 1), total distance (p = 0.02, ES = 0.87), as well as maximum speed (p = 0.02, ES = 0.87)]. A trend towards improvement was observed in the remaining performance indicators (i.e., distance/min and avg speed; ES = 0.6), training load (ES = 0.2), muscle status (ES = 0.3)), and all physiological responses parameters (ES = 0.1 to 0.6). Significant correlations were found between the majority of external load parameters (i.e., performance indicators) and objective (i.e., physiological responses) and subjective (i.e., RPE, muscle status) internal load parameters (p < 0.001). The highest number of moderate-large correlations were registered between performance indicators and time in HR zone 4+5 (0.58 < r < 0.82), training load (0.53 < r < 0.83), average HR (0.50 < r < 0.87), maximal HR (0.51 < r < 0.54) and average R-R interval (0.58 < r < 0.76). HR zone 4+5, average and maximal HR, average R-R interval, and training load score may help control training parameters and reduce the risk of under- or over-training in youth soccer players. However, these conclusions should be confirmed and replicated in future studies with more diverse subject populations.     

Preperoxisomal vesicles can form in the absence of Pex3

We demonstrate that the peroxin Pex3 is not required for the formation of peroxisomal membrane structures in yeast pex3 mutant cells. Notably, pex3 mutant cells already contain reticular and vesicular structures that harbor key proteins of the peroxisomal receptor docking complex—Pex13 and Pex14—as well as the matrix proteins Pex8 and alcohol oxidase. Other peroxisomal membrane proteins in these cells are unstable and transiently localized to the cytosol (Pex10, Pmp47) or endoplasmic reticulum (Pex11). These reticular and vesicular structures are more abundant in cells of a pex3 atg1 double deletion strain, as the absence of Pex3 may render them susceptible to autophagic degradation, which is blocked in this double mutant. Contrary to earlier suggestions, peroxisomes are not formed de novo from the endoplasmic reticulum when the PEX3 gene is reintroduced in pex3 cells. Instead, we find that reintroduced Pex3 sorts to the preperoxisomal structures in pex3 cells, after which these structures mature into normal peroxisomes.     

Mechanism of loading the Escherichia coli DNA polymerase III sliding clamp: II. Uncoupling the beta and DNA binding activities of the gamma complex

Sliding clamps tether DNA polymerases to DNA to increase the processivity of synthesis. The Escherichia coli gamma complex loads the beta sliding clamp onto DNA in an ATP-dependent reaction in which ATP binding and hydrolysis modulate the affinity of the gamma complex for beta and DNA. This is the second of two reports (Williams, C. R., Snyder, A. K., Kuzmic, P., O'Donnell, M., and Bloom, L. B. (2004) J. Biol. Chem. 279, 4376-4385) addressing the question of how ATP binding and hydrolysis regulate specific interactions with DNA and beta. Mutations were made to an Arg residue in a conserved SRC motif in the delta' and gamma subunits that interacts with the ATP site of the neighboring gamma subunit. Mutation of the delta' subunit reduced the ATP-dependent beta binding activity, whereas mutation of the gamma subunits reduced the DNA binding activity of the gamma complex. The gamma complex containing the delta' mutation gave a pre-steady-state burst of ATP hydrolysis, but at a reduced rate and amplitude relative to the wild-type gamma complex. A pre-steady-state burst of ATP hydrolysis was not observed for the complex containing the gamma mutations, consistent with the reduced DNA binding activity of this complex. The differential effects of these mutations suggest that ATP binding at the gamma1 site may be coupled to conformational changes that largely modulate interactions with beta, whereas ATP binding at the gamma2 and/or gamma3 site may be coupled to conformational changes that have a major role in interactions with DNA. Additionally, these results show that the "arginine fingers" play a structural role in facilitating the formation of a conformation that has high affinity for beta and DNA.     

MEL-28 is downstream of the Ran cycle and is required for nuclear-envelope function and chromatin maintenance

Early embryonic development depends on the faithful execution of basic cell biological processes whose coordination remains largely unknown. With a global network analysis, we found MEL-28 to be associated with two types of complexes, one implicated in nuclear-envelope function and the other in chromatin organization. Here, we show that MEL-28, a protein that shuttles between the nucleus and the kinetochore during the cell cycle, is required for the structural and functional integrity of the nuclear envelope. In addition, mel-28(RNAi) embryos exhibit defects in chromosome condensation, pronuclear migration, kinetochore assembly, and spindle assembly. This combination of mel-28(RNAi) phenotypes resemble those caused by depleting members of the Ran cycle in C. elegans, a conserved cellular signaling pathway that is required for mitotic spindle assembly, nuclear-envelope reformation after mitosis, and nucleocytoplasmic exchange (reviewed in). Although MEL-28 localization to the nuclear periphery is not dependent on nuclear pore components, it is dependent on RAN-1 and other key components of the Ran cycle. Thus, MEL-28 is downstream of the Ran cycle and is required for both proper nuclear-envelope function and chromatin maintenance.