Developmental Expression of Neural Cell Adhesion Molecules of Oligodendrocytes In Vivo and in Culture

Abstract: Previously, we have shown that oligodendrocyte adhesion molecules are related to the 120,000–M_r neural cell adhesion molecule (NCAM-120). In this report, we present further evidence that the oligodendrocyte adhesion molecule is NCAM-120. Studies on the expression of NCAM-120 and other molecular forms of NCAM in vivo in rat brain, in vitro in primary mixed cultures, and in cultures enriched for oligodendrocytes are described. Western blot analysis of rat brain using anti-NCAM showed that NCAM-120 first appears at postnatal day 7 and increases in quantity thereafter, coincident with the development of oligodendrocytes in vivo and comparable to the expression of myelin basic protein. Purified oligodendrocytes from 4-week-old rat brains expressed only NCAM-120. Quantitation of various forms of NCAMs in rat brain showed marked age-related differences in the expression of three molecular forms of NCAM. Immunofluorescence analysis showed that oligodendrocytes, at all ages tested, expressed NCAM, but in older oligodendrocytes, the intensity of staining was less. Western blot analysis of oligodendrocyte-enriched cultures showed that from day 1 after isolation (12 days of age) through day 7 after isolation (18 days of age) only NCAM-120 is seen. A possible role for NCAM in myelination and remyelination is discussed.     

Exploring the Structural Mechanism of Covalently Bound E3 Ubiquitin Ligase: Catalytic or Allosteric Inhibition?

Covalent inhibition has recently gained a resurgence of interest in several drug discovery areas. The expansion of this approach is based on evidence elucidating the selectivity and potency of covalent inhibitors when bound to particular amino acids of a biological target. The Nedd4-1, an E3 ubiquitin ligase, is characterized by two covalent binding sites, of which catalytic Cys^cat and allosteric Cys^allo are enclosed. This enzyme has demonstrated inhibition at both the above-mentioned binding sites; however, a detailed molecular understanding of the structural mechanism of inhibition upon Cys^cat and Cys^allo binding remains vague. This prompted us to provide the first account of investigating the preferential covalent binding mode and the underlying structural and molecular dynamic implications. Based on the molecular dynamic analyses, it was evident that although both catalytic and allosteric covalent binding led to greater stability of the enzyme, a preferential covalent mechanism of inhibition was seen in the allosteric-targeted system. This was supported by a more favorable binding energy in the allosteric site compared to the catalytic site, in addition to the larger number of residue interactions and stabilizing hydrogen bonds occurring in the allosteric covalent bound complex. The fundamental dynamic analysis presented in this report compliments, as well as adds to previous experimental findings, thus leading to a crucial understanding of the structural mechanism by which Nedd4-1 is inhibited. The findings from this study may assist in the design of more target-specific Nedd4-1 covalent inhibitors exploring the surface-exposed cysteine residues.     

Novel nicotinamide analog as inhibitor of nicotinamide N-methyltransferase

Nicotinamide N-methyltransferase (NNMT) has been linked to obesity and diabetes. We have identified a novel nicotinamide (NA) analog, compound 12 that inhibited NNMT enzymatic activity and reduced the formation of 1-methyl-nicotinamide (MNA), the primary metabolite of NA by ～80% at 2?h when dosed in mice orally at 50?mg/kg.     

Prospects for ethanol production from cellulose withClostridium thermocellum-Bacillus stearothermophilus co-cultures

Summary A lactate dehydrogenase deficient, high ethanol yielding mutant ofB. stearothermophilus was successfully co-cultured withC. thermocellum on cellulose. The co-culture produced 50% more ethanol and a 75% higher level of CMCase activity than theC. thermocellum mono-culture.     

Physiological and biochemical studies on psychrotolerance in Listeria monocytogenes

Studies were undertaken to explain the ability of Listeria monocytogenes to grow at low temperatures in a chemostat. It was found that when grown in continuous culture at a dilution rate of 0·02 h⁻¹ L. monocytogenes had a lower proportion of anteiso -17:0, and a higher proportion of anteiso -15:0, and smaller chain fatty acids when grown at 10°C compared to 30°C. A previously unreported glycolipid was only seen after growth at low temperature. Growth temperature had no effect on the rate of glucose uptake.     

A requirement for NF-protocadherin and TAF1/Set in cell adhesion and neural tube formation

Neurulation in vertebrates is an intricate process requiring extensive alterations in cell contacts and cellular morphologies as the cells in the neural ectoderm shape and form the neural folds and neural tube. Despite these complex interactions, little is known concerning the molecules that mediate cell adhesion within the embryonic neural plate and neural folds. Here, we demonstrate the requirement for NF-protocadherin (NFPC) and its cytosolic partner TAF1/Set for proper neurulation in Xenopus. Both NFPC and TAF1 function in cell-cell adhesion in the neural ectoderm, and disruptions in either NFPC or TAF1 result in a failure of the neural tube to close. This neural tube defect can be attributed to a lack of proper organization of the cells in the dorsal neural folds, manifested by a loss in the columnar epithelial morphology and apical localization of F-actin. However, the epidermal ectoderm is still able to migrate and cover the open neural tube, indicating that the fusions of the neural tube and epidermis are separate events. These studies demonstrate that NFPC and TAF1 function to maintain proper cell-cell interactions within the neural folds and suggest that NFPC and TAF1 participate in novel adhesive mechanisms that contribute to the final events of vertebrate neurulation.     

Maternal body mass index and risk of testicular cancer in male offspring: A systematic review and meta-analysis

Objectives: To date a number of studies have examined the association between maternal weight and testicular cancer risk although results have been largely inconsistent. This systematic review and meta-analysis investigated the nature of this association. Methods: Search strategies were conducted in Ovid Medline (1950–2009), Embase (1980–2009), Web of Science (1970–2009), and CINAHL (1937–2009) using keywords for maternal weight (BMI) and testicular cancer. Results: The literature search produced 1689 hits from which 63 papers were extracted. Only 7 studies met the pre-defined criteria. Random effects meta-analyses were conducted. The combined unadjusted OR (95% CI) of testicular cancer in the highest reported category of maternal BMI compared with the moderate maternal BMI was 0.82 (0.65–1.02). The Cochran's Q P value was 0.82 and the corresponding I² was 0%, both indicating very little variability among studies. The combined unadjusted OR (95% CI) for testicular cancer risk in the lowest reported category of maternal BMI compared to a moderate maternal BMI category was 0.88 (0.65–1.20). The Cochran's Q P value was 0.05 and the corresponding I² was 54%, indicating evidence of statistical heterogeneity. The combined unadjusted OR (95% CI) of testicular cancer risk per unit increase in maternal BMI was 1.01 (0.97–1.06). The Cochran's Q test had a P value of 0.05 and the corresponding I² was 55% indicating evidence of statistical heterogeneity. Conclusion: This meta-analysis, which included a small number of studies, showed that a higher maternal weight does not increase the risk of testicular cancer in male offspring. Though an inverse association between high maternal BMI and testicular cancer risk was detected, it was not statistically significant. Further primary studies with adjustment for appropriate confounders are required.