Induction of transient ion channel-like pores in a cancer cell by antibiotic peptide

The anticancer activity of anti-bacterial cecropins makes them potentially useful as peptide anti-cancer drugs. We used the cell-attached patch to study the effect of cecropin B (CB; having one hydrophobic and one amphipathic alpha-helix) and its derivative, cecropin B3 (CB3; having two hydrophobic alpha-helices) on the membrane of Ags cancer cells. Application of 10-60 microM CB onto the membrane of the cancer cell produces short outward currents. Comparative study with CB3, which induces no outward currents, shows that the amphipathic group of CB is necessary for the pore formation. The results provide a rationale to study the cell-killing activity of antimicrobial peptides at the single cancer cell level.     

Do mitochondria make nitric oxide? no?

Several papers have claimed that mitochondria contain nitric oxide synthase (NOS) and make nitric oxide (NO*) in amounts sufficient to affect mitochondrial respiration. However, we found that the addition of L-arginine or the NOS inhibitor L-NMMA to intact rat liver mitochondria did not have any effect on the respiratory rate in both State 3 and State 4. We did not detect mitochondrial NO* production by the oxymyoglobin oxidation assay, or electrochemically using an NO* electrode. An apparent NO* production detected by the Griess assay was identified as an artifact. NO* generated by eNOS added to the mitochondria could easily be detected, although succinate-supplemented mitochondria appeared to consume NO*. Our data show that NO* production by normal rat liver mitochondria cannot be detected in our laboratory, even though the levels of production claimed in the literature should easily have been measured by the techniques used. The implications for the putative mitochondrial NOS are discussed.     

Repeated triggering of sporulation in Bacillus subtilis selects against a protein that affects the timing of cell division

Bacillus subtilis sporulation is a last-resort phenotypical adaptation in response to starvation. The regulatory network underlying this developmental pathway has been studied extensively. However, how sporulation initiation is concerted in relation to the environmental nutrient availability is poorly understood. In a fed-batch fermentation set-up, in which sporulation of ultraviolet (UV)-mutagenized B. subtilis is repeatedly triggered by periods of starvation, fitter strains with mutated tagE evolved. These mutants display altered timing of phenotypical differentiation. The substrate for the wall teichoic acid (WTA)-modifying enzyme TagE, UDP-glucose, has recently been shown to be an intracellular proxy for nutrient availability, and influences the timing of cell division. Here we suggest that UDP-glucose also influences timing of cellular differentiation.     

Purification and characterization of α-glucosidase from Aspergillus carbonarious

Summary An -glucosidase was purified from Aspergillus carbonarious CCRC 30414 over 20 fold with 37 % recovery. Its molecular mass was estimated to be 328 kDa by gel filtration with an optimum pH from 4.2 to 5.0, and pI=5.0. The optimum temperature is at 60°C over 40 min. The enzyme was partially inhibited by 5 mM Ag⁺, Hg²⁺, Ba²⁺, Pb²⁺, and Aso₄ ⁺.     

Skeletal muscle adiposity is associated with serum lipid and lipoprotein levels in Afro‐Caribbean men

Objective: When compared with other ethnic groups, African ancestry individuals have lower triglycerides and higher High‐density lipoprotein cholesterol (HDL‐C) levels, although the mechanisms for these differences remain unclear. A comprehensive array of factors potentially related to fasting serum lipid and lipoprotein levels in African ancestry men was evaluated. Design and Methods: Men (1,821) underwent dual‐energy X‐ray absorptiometry measures of total body fat and quantitative computed tomography assessments of calf skeletal muscle adiposity [subcutaneous and intermuscular adipose tissue (AT), and muscle density as a measure of intra‐muscular AT]. Results: Multivariable linear regression analysis identified age (?), total body fat (+), subcutaneous AT (?), fasting glucose (+), fasting insulin (+), diastolic blood pressure (+), and non‐African ancestry (+) as independent correlates of triglycerides (all P < 0.05). Total body fat (+), intra‐muscular AT (?), and diastolic blood pressure (+) were independent correlates of Low‐density lipoprotein cholesterol (LDL‐C) (all P < 0.001). Age (+), waist circumference (?), fasting insulin (?), physical activity (+), and alcohol intake (+) were independent correlates of HDL‐C (all P < 0.05). Conclusions: A novel relationship between skeletal muscle adiposity and serum lipid and lipoprotein levels in African ancestry men, independent of total and central adiposity was illuminated. In African ancestry populations, genetic factors are likely a significant determinant of triglycerides levels.     

<Emphasis Type="Italic">Aquimarina salinaria</Emphasis> sp. nov., a novel algicidal bacterium isolated from a saltpan

A bacterial strain designated antisso-27^T, previously isolated from saltpan in Taiwan while screening for bacteria for algicidal activity, was characterized using the polyphasic taxonomic approach. Strain antisso-27^T was Gram-negative, aerobic, brownish yellow colored, rod-shaped, non-flagellated and non-gliding. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain antisso-27^T belonged to the genus Aquimarina within the family Flavobacteriaceae with relatively low sequence similarities of 94.0–96.6% to other valid Aquimarina spp. It contained iso-C_17:0 3-OH, iso-C_15:0, iso-C_16:0, iso-C_15:1 and iso-C_15:0 3-OH as the main fatty acids and contained a menaquinone with six isoprene units (MK-6) as the major isoprenoid quinone. Major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, an uncharacterized aminolipid and five uncharacterized phospholipids. Strain antisso-27^T employed direct mode of algicidal lysis to Chlorella vulgaris strain 211-31; nevertheless, it released an algicidal substance against M. aeruginosa strain MTY01. This is the first study that the Aquimarina species possesses both direct and indirect algicidal activities. On the basis of the phylogenetic and phenotypic data, strain antisso-27^T should be classified as representing a novel species, for which the name A. salinaria sp. nov. is proposed. The type strain is A. salinaria antisso-27^T (= BCRC 80080^T = LMG 25375^T).     

PMC,a potent hydrophilic α‐tocopherol derivative,inhibits NF‐κB activation via PP2A but not IκBα‐dependent signals in vascular smooth muscle cells

The hydrophilic α‐tocopherol derivative, 2,2,5,7,8‐pentamethyl‐6‐hydroxychromane (PMC), is a promising alternative to vitamin E in clinical applications. Critical vascular inflammation leads to vascular dysfunction and vascular diseases, including atherosclerosis, hypertension and abdominal aortic aneurysms. In this study, we investigated the mechanisms of the inhibitory effects of PMC in vascular smooth muscle cells (VSMCs) exposed to pro‐inflammatory stimuli, lipopolysaccharide (LPS) combined with interferon (IFN)‐γ. Treatment of LPS/IFN‐γ‐stimulated VSMCs with PMC suppressed the expression of inducible nitric oxide synthase (iNOS) and matrix metalloproteinase‐9 in a concentration‐dependent manner. A reduction in LPS/IFN‐γ‐induced nuclear factor (NF)‐κB activation was also observed in PMC‐treated VSMCs. The translocation and phosphorylation of p65, protein phosphatase 2A (PP2A) inactivation and the formation of reactive oxygen species (ROS) were significantly inhibited by PMC in LPS/IFN‐γ‐activated VSMCs. However, neither IκBα degradation nor IκB kinase (IKK) or ribosomal s6 kinase‐1 phosphorylation was affected by PMC under these conditions. Both treatments with okadaic acid, a PP2A‐selective inhibitor, and transfection with PP2A siRNA markedly reversed the PMC‐mediated inhibition of iNOS expression, NF‐κB‐promoter activity and p65 phosphorylation. Immunoprecipitation analysis of the cellular extracts of LPS/IFN‐γ‐stimulated VSMCs revealed that p65 colocalizes with PP2A. In addition, p65 phosphorylation and PP2A inactivation were induced in VSMCs by treatment with H₂O₂, but neither IκBα degradation nor IKK phosphorylation was observed. These results collectively indicate that the PMC‐mediated inhibition of NF‐κB activity in LPS/IFN‐γ‐stimulated VSMCs occurs through the ROS‐PP2A‐p65 signalling cascade, an IKK‐IκBα‐independent mechanism. Therapeutic interventions using PMC may therefore be beneficial for the treatment of vascular inflammatory diseases.     

Anti-oxidant activity and effect of Pinus morrisonicola Hay. on the survival of leukemia cell line U937

The free radical scavenging and anti-cancer activites of Pinus morrisonicola Hay. were studied using different parts of the pine, namely, needle, bark and cone. Results showed that pine needle water extract has the highest scavenging superoxide anion activity and the lowest IC50 value in inhibiting superoxide anion formation; however, the bark water extract showed the best anti-lipid peroxidation activity. Additionally, needle water extract displayed the highest inhibition of leukemia cell line U937 growth. The results indicated that P. morrisonicola Hay. possesses potential chemopreventative and therapeutic properties.     

Neurogenetic interactions and aberrant behavioral co-morbidity of attention deficit hyperactivity disorder (ADHD): dispelling myths

Background

Attention Deficit Hyperactivity Disorder, commonly referred to as ADHD, is a common, complex, predominately genetic but highly treatable disorder, which in its more severe form has such a profound effect on brain function that every aspect of the life of an affected individual may be permanently compromised. Despite the broad base of scientific investigation over the past 50 years supporting this statement, there are still many misconceptions about ADHD. These include believing the disorder does not exist, that all children have symptoms of ADHD, that if it does exist it is grossly over-diagnosed and over-treated, and that the treatment is dangerous and leads to a propensity to drug addiction. Since most misconceptions contain elements of truth, where does the reality lie?

Results

We have reviewed the literature to evaluate some of the claims and counter-claims. The evidence suggests that ADHD is primarily a polygenic disorder involving at least 50 genes, including those encoding enzymes of neurotransmitter metabolism, neurotransmitter transporters and receptors. Because of its polygenic nature, ADHD is often accompanied by other behavioral abnormalities. It is present in adults as well as children, but in itself it does not necessarily impair function in adult life; associated disorders, however, may do so. A range of treatment options is reviewed and the mechanisms responsible for the efficacy of standard drug treatments are considered.

Conclusion

The genes so far implicated in ADHD account for only part of the total picture. Identification of the remaining genes and characterization of their interactions is likely to establish ADHD firmly as a biological disorder and to lead to better methods of diagnosis and treatment.