α-Syntrophin Modulates Myogenin Expression in Differentiating Myoblasts

α-Syntrophin is a scaffolding protein linking signaling proteins to the sarcolemmal dystrophin complex in mature muscle. However, α-syntrophin is also expressed in differentiating myoblasts during the early stages of muscle differentiation. In this study, we examined the relationship between the expression of α-syntrophin and myogenin, a key muscle regulatory factor.The absence of α-syntrophin leads to reduced and delayed myogenin expression. This conclusion is based on experiments using muscle cells isolated from α-syntrophin null mice, muscle regeneration studies in α-syntrophin null mice, experiments in Sol8 cells (a cell line that expresses only low levels of α-syntrophin) and siRNA studies in differentiating C2 cells. In primary cultured myocytes isolated from α-syntrophin null mice, the level of myogenin was less than 50% that from wild type myocytes (p<0.005) 40 h after differentiation induction. In regenerating muscle, the expression of myogenin in the α-syntrophin null muscle was reduced to approximately 25% that of wild type muscle (p<0.005). Conversely, myogenin expression is enhanced in primary cultures of myoblasts isolated from a transgenic mouse over-expressing α-syntrophin and in Sol8 cells transfected with a vector to over-express α-syntrophin. Moreover, we find that myogenin mRNA is reduced in the absence of α-syntrophin and increased by α-syntrophin over-expression. Immunofluorescence microscopy shows that α-syntrophin is localized to the nuclei of differentiating myoblasts. Finally, immunoprecipitation experiments demonstrate that α-syntrophin associates with Mixed-Lineage Leukemia 5, a regulator of myogenin expression.We conclude that α-syntrophin plays an important role in regulating myogenesis by modulating myogenin expression

Characterization of LysB4, an endolysin from the Bacillus cereus-infecting bacteriophage B4

<p>Abstract</p> <p>Background</p> <p><it>Bacillus cereus </it>is a foodborne pathogen that causes emetic or diarrheal types of food poisoning. The incidence of <it>B. cereus </it>food poisoning has been gradually increasing over the past few years, therefore, biocontrol agents effective against <it>B. cereus </it>need to be developed. Endolysins are phage-encoded bacterial peptidoglycan hydrolases and have received considerable attention as promising antibacterial agents.</p> <p>Results</p> <p>The endolysin from <it>B. cereus </it>phage B4, designated LysB4, was identified and characterized. <it>In silico </it>analysis revealed that this endolysin had the VanY domain at the N terminus as the catalytic domain, and the SH3_5 domain at the C terminus that appears to be the cell wall binding domain. Biochemical characterization of LysB4 enzymatic activity showed that it had optimal peptidoglycan hydrolase activity at pH 8.0-10.0 and 50°C. The lytic activity was dependent on divalent metal ions, especially Zn²⁺. The antimicrobial spectrum was relatively broad because LysB4 lysed Gram-positive bacteria such as <it>B. cereus, Bacillus subtilis </it>and <it>Listeria monocytogenes </it>and some Gram-negative bacteria when treated with EDTA. LC-MS analysis of the cell wall cleavage products showed that LysB4 was an <smcaps>L</smcaps>-alanoyl-<smcaps>D</smcaps>-glutamate endopeptidase, making LysB4 the first characterized endopeptidase of this type to target <it>B. cereus</it>.</p> <p>Conclusions</p> <p>LysB4 is believed to be the first reported <smcaps>L</smcaps>-alanoyl-<smcaps>D</smcaps>-glutamate endopeptidase from <it>B. cereus</it>-infecting bacteriophages. The properties of LysB4 showed that this endolysin has strong lytic activity against a broad range of pathogenic bacteria, which makes LysB4 a good candidate as a biocontrol agent against <it>B. cereus </it>and other pathogenic bacteria.</p

Gene expression profiling of chicken primordial germ cell ESTs

BACKGROUND: Germ cells are the only cell type that can penetrate from one generation to next generation. At the early embryonic developmental stages, germ cells originally stem from primordial germ cells, and finally differentiate into functional gametes, sperm in male or oocyte in female, after sexual maturity. This study was conducted to investigate a large-scale expressed sequence tag (EST) analysis in chicken PGCs and compare the expression of the PGC ESTs with that of embryonic gonad. RESULTS: We constructed 10,851 ESTs from a chicken cDNA library of a collection of highly separated embryonic PGCs. After chimeric and problematic sequences were filtered out using the chicken genomic sequences, there were 5,093 resulting unique sequences consisting of 156 contigs and 4,937 singlets. Pearson chi-square tests of gene ontology terms in the 2nd level between PGC and embryonic gonad set showed no significance. However, digital gene expression profiling using the Audic's test showed that there were 2 genes expressed significantly with higher number of transcripts in PGCs compared with the embryonic gonads set. On the other hand, 17 genes in embryonic gonads were up-regulated higher than those in the PGC set. CONCLUSION: Our results in this study contribute to knowledge of mining novel transcripts and genes involved in germline cell proliferation and differentiation at the early embryonic stages

Prevalence of sarcopenia and sarcopenic obesity in Korean adults: The Korean Sarcopenic Obesity Study (KSOS)

*Context:* Sarcopenic obesity (SO), a combination of excess weight and reduced muscle mass and/or strength, is suggested to be associated with an increased risk of adverse health outcomes. &#xd;&#xa;*Objectives:* To examine the prevalence and characteristics of Sarcopenic and SO defined by using different indices such as Appendicular Skeletal muscle Mass (ASM)/height^2^ and Skeletal Muscle Index (SMI (%): skeletal muscle mass (kg)/weight (kg) &#xd7; 100) for Korean adults. &#xd;&#xa;*Methods:* 591 participants were recruited from the Korean Sarcopenic Obesity Study (KSOS) which is an ongoing prospective observational cohort study. Analysis was conducted in 526 participants (328 women, 198 men) who had complete data on body composition using Dual X-ray absorptiometry and computed tomography. &#xd;&#xa;*Results:* The prevalence of sarcopenia and SO increases with aging. Using two or more standard deviations (SD) of ASM/height^2^ below reference values from young, healthy adults as a definition of sarcopenia, the prevalence of sarcopenia and SO was 6.3% and 1.3% in men and 4.1% and 1.7% in women over 60 years of age. However, using two or more SD of SMI, the prevalence of sarcopenia and SO was 5.1% and 5.1% respectively in men and 14.2% and 12.5% respectively in women. As defined by SMI, subjects with SO had 3 times the risk of metabolic syndrome (OR = 3.03, 95% confidence interval (CI) = 1.26-7.26) and subjects with non-sarcopenic obesity had approximately 2 times the risk of metabolic syndrome (OR = 1.89, 95% CI = 1.18-3.02) compared with normal subjects. &#xd;&#xa;*Conclusion:* Obese subjects with relative sarcopenia were associated with a greater likelihood for metabolic syndrome. As Koreans were more obese and aging, the prevalence of SO and its impact on health outcomes are estimated to be rapidly grow. Further research is requested to establish the definition, cause and consequences of SO.&#xd;&#xa

L-Asparaginase delivered by Salmonella typhimurium suppresses solid tumors

Bacteria can be engineered to deliver anticancer proteins to tumors via a controlled expression system that maximizes the concentration of the therapeutic agent in the tumor. L-asparaginase (L-ASNase), which primarily converts asparagine to aspartate, is an anticancer protein used to treat acute lymphoblastic leukemia. In this study, Salmonellae were engineered to express L-ASNase selectively within tumor tissues using the inducible araBAD promoter system of Escherichia coli. Antitumor efficacy of the engineered bacteria was demonstrated in vivo in solid malignancies. This result demonstrates the merit of bacteria as cancer drug delivery vehicles to administer cancer-starving proteins such as L-ASNase to be effective selectively within the microenvironment of cancer tissue

TLR4 mutation reduces microglial activation, increases Aβ deposits and exacerbates cognitive deficits in a mouse model of Alzheimer's disease

<p>Abstract</p> <p>Background</p> <p>Amyloid plaques, a pathological hallmark of Alzheimer's disease (AD), are accompanied by activated microglia. The role of activated microglia in the pathogenesis of AD remains controversial: either clearing Aβ deposits by phagocytosis or releasing proinflammatory cytokines and cytotoxic substances. Microglia can be activated via toll-like receptors (TLRs), a class of pattern-recognition receptors in the innate immune system. We previously demonstrated that an AD mouse model homozygous for a loss-of-function mutation of TLR4 had increases in Aβ deposits and buffer-soluble Aβ in the brain as compared with a TLR4 wild-type AD mouse model at 14-16 months of age. However, it is unknown if TLR4 signaling is involved in initiation of Aβ deposition as well as activation and recruitment of microglia at the early stage of AD. Here, we investigated the role of TLR4 signaling and microglial activation in early stages using 5-month-old AD mouse models when Aβ deposits start.</p> <p>Methods</p> <p>Microglial activation and amyloid deposition in the brain were determined by immunohistochemistry in the AD models. Levels of cerebral soluble Aβ were determined by ELISA. mRNA levels of cytokines and chemokines in the brain and Aβ-stimulated monocytes were quantified by real-time PCR. Cognitive functions were assessed by the Morris water maze.</p> <p>Results</p> <p>While no difference was found in cerebral Aβ load between AD mouse models at 5 months with and without TLR4 mutation, microglial activation in a TLR4 mutant AD model (TLR4M Tg) was less than that in a TLR4 wild-type AD model (TLR4W Tg). At 9 months, TLR4M Tg mice had increased Aβ deposition and soluble Aβ42 in the brain, which were associated with decrements in cognitive functions and expression levels of IL-1β, CCL3, and CCL4 in the hippocampus compared to TLR4W Tg mice. TLR4 mutation diminished Aβ-induced IL-1β, CCL3, and CCL4 expression in monocytes.</p> <p>Conclusion</p> <p>This is the first demonstration of TLR4-dependent activation of microglia at the early stage of β-amyloidosis. Our results indicate that TLR4 is not involved in the initiation of Aβ deposition and that, as Aβ deposits start, microglia are activated via TLR4 signaling to reduce Aβ deposits and preserve cognitive functions from Aβ-mediated neurotoxicity.</p

Controlled Doping of Electrocatalysts through Engineering Impurities

Fuel cells recombine water from H-2 and O-2 thereby can power, for example, cars or houses with no direct carbon emission. In anion-exchange membrane fuel cells (AEMFCs), to reach high power densities, operating at high pH is an alternative to using large volumes of noble metals catalysts at the cathode, where the oxygen-reduction reaction occurs. However, the sluggish kinetics of the hydrogen-oxidation reaction (HOR) hinders upscaling despite promising catalysts. Here, the authors observe an unexpected ingress of B into Pd nanocatalysts synthesized by wet-chemistry, gaining control over this B-doping, and report on its influence on the HOR activity in alkaline conditions. They rationalize their findings using ab initio calculations of both H- and OH-adsorption on B-doped Pd. Using this "impurity engineering" approach, they thus design Pt-free catalysts as required in electrochemical energy conversion devices, for example, next generations of AEMFCs, that satisfy the economic and environmental constraints, that is, reasonable operating costs and long-term stability, to enable the "hydrogen economy.

KITENIN increases invasion and migration of mouse squamous cancer cells and promotes pulmonary metastasis in a mouse squamous tumor model

AbstractKAI1 C-terminal interacting tetraspanin (KITENIN) is reported to promote metastasis in mouse colon cancer models. We investigated the role of KITENIN on the progression of squamous cell carcinoma (SCC). In a preliminary clinical study using resected tissues from head and neck SCC patients, KITENIN was highly expressed in tumors and metastatic lymph nodes, while KAI1 was more increased in adjacent mucosa than in tumor. KITENIN-transfected mouse squamous cancer (SCC VII/KITENIN) cells showed significantly higher invasion, migration, and proliferation than empty vector-transfected cells. In syngeneic mouse squamous tumor models, more increased tumor volume and enhanced lung metastasis were found in SCC VII/KITENIN cells-injected mice. Thus, KITENIN increases invasion and migration of squamous cancer cells and thereby promotes distant metastasis in mouse squamous tumor models