Toxic Bacillus pumilus from indoor air, Recycled Paper Pulp,Norway Spruce, Food Poisoning Outbreaks and Clinical Samples

Forty-four B. pumilus isolates of food poisoning, clinical, environmental and industrial origins were investigated for toxin production using the boar spermatozoan motility assay, previously shown to be a sensitive method for detecting non-protein toxins from B. cereus and B. licheniformis. The three toxic isolates originated from live tree, indoor air and recycled paper pulp and were more toxic than the previously described food poisoning isolates of B. licheniformis, whereas the B. pumilus food poisoning and clinical isolates were lower in toxicity. The type strain also produced inhibitory substances. The toxic substances were insensitive to heat (100 °C, 20 min), to pH 2 or pH 10 and to digestion with pronase. The substances were readily soluble in methanol and chloroform, but less soluble in toluene. Exposure of boar spermatozoa to 1–10 μg ml^–1 (EC₅₀) of methanol soluble substance from the four strains disrupted the plasma membrane permeability barrier, induced abnormalities in the postacrosomal sheath, collapsed the mitochondrial and suppressed cytoplasmic NAD reduction. No change was observed in human peripheral blood lymphocytes exposed to concentrations of B. pumilus extract that affected spermatozoa. The toxin producing isolates were 99.4 to 99.6% similar in 16SrDNA (500 bp) to the type strain and could not be distinguished from the 41 non-toxic isolates by biochemical properties or whole cell fatty acid composition.     

Cloning of the regulatory locus ompB of Salmonella typhimurium LT-2

Summary We have cloned the complete functional ompB locus of Salmonella typhimurium LT-2 into Escherichia coli K-12 using a cosmid vector and in vitro packaging into . The ompB locus of Salmonella was found to complement both envZ and ompR mutations in E. coli as well as an ompR mutation of Salmonella. The ompR part of the ompB locus was further subcloned into the multicopy plasmid pKN410 as a 1.3 kb fragment. This fragment coded for a single 28.5 kd protein corresponding to about 820 bp in length. Furthermore, the OmpR proteins of S. typhimurium and E. coli were shown to be structurally and functionally highly similar.Abbreviations SDS sedium dodecyl sulfate - kb kilobase pairs - bp base pairs - kd kilodaltons     

Periodontal infections and atherosclerosis: mere associations?

PURPOSE OF REVIEW: Several lines of evidence from the last few decades suggest that periodontitis is an important risk factor for cardiovascular diseases. In this review we discuss the recent findings on the systemic effects of periodontitis, which may contribute to the pathogenesis of atherosclerosis, with a special emphasis on lipoproteins. RECENT FINDINGS: In addition to the epidemiological studies exploring the direct or indirect relationship between clinical periodontitis and cardiovascular diseases, studies utilizing serology, animal models, cell cultures, and biochemistry of lipoproteins have been published. Local infection in the periodontal pockets triggers a systemic inflammatory response releasing inflammatory mediators and awakens a strong immune response against periodontal pathogens. Elevated systemic antibody levels especially to Porphyromonas gingivalis are associated with an increased risk for atherosclerosis. Periodontitis is also accompanied by proatherogenic changes in both low and high density lipoproteins, which lead to enhanced cholesteryl ester uptake by and reduced cholesterol efflux from macrophages. Vesicles and lipopolysaccharide isolated from P. gingivalis activate macrophages to convert into foam cells. Moreover, animal studies have demonstrated that infection by P. gingivalis enhances progression of atherosclerosis. SUMMARY: Recent studies have clarified the mechanisms by which periodontitis may contribute to the development of atherosclerosis. Serological, animal, and cell culture studies provide evidence that infection by P. gingivalis may promote atherosclerosis. The influence of periodontitis on lipoprotein metabolism has emerged as a new, important factor. Recent studies provide experimental proof that periodontitis may predispose to atherosclerosis.     

Hormonal responses to a resistance exercise performed under the influence of delayed onset muscle soreness

Hormonal responses to an unaccustomed knee-extension exercise (E1; 5 times 10 repetitions with 40% load of 1RM [1 repetition maximum] followed by 2 sets until exhaustion) were compared in 6 men with the corresponding responses to an identical exercise performed 2 days later under the influence of delayed onset muscle soreness (DOMS) (E2). Both exercises were performed with a variable-resistance machine causing exhaustion with significantly fewer repetitions than a normal constant-resistance knee-extension device does. The E1 induced DOMS as expected, but the 1RM, the total work done, and the repetition number and frequency were not different in the 2 exercises. In the 2 sets to failure, the mean repetition number varied between 17 and 25. The exercise-induced norepinephrine, epinephrine, testosterone, cortisol (COR), and growth hormone (GH) increases were similar in the 2 exercises, although the overall level of COR and GH, including the preexercise concentrations, tended to decline in the second exercise. The results may thus suggest that the hormonal response to resistance exercise is not significantly altered when performed soon after an unaccustomed exercise bout leading to DOMS.     

Sex steroid hormone metabolism takes place in human ocular cells

Steroids are potentially important mediators in the pathophysiology of ocular diseases. In this study, we report on the gene expression in the human eye of a group of enzymes, the 17beta-hydroxysteroid dehydrogenases (17HSDs), involved in the biosynthesis and inactivation of sex steroid hormones. In the eye, the ciliary epithelium, a neuroendocrine secretory epithelium, co-expresses the highest levels of 17HSD2 and 5 mRNAs, and in lesser level 17HSD7 mRNA. The regulation of gene expression of these enzymes was investigated in vitro in cell lines, ODM-C4 and chronic open glaucoma (GCE), used as cell models of the human ciliary epithelium. The estrogen, 17beta-estradiol (10(-7) M) and androgen agonist, R1881 (10(-8) M) elicited in ODM-C4 and GCE cells over a 24 h time course a robust up-regulation of 17HSD7 mRNA expression. 17HSD2 was up-regulated by estradiol in ODM-C4 cells, but not in GCE cells. Under steady-state conditions, ODM-C4 cells exhibited a predominant 17HSD2 oxidative enzymatic activity. In contrast, 17HSD2 activity was low or absent in GCE cells. Our collective data suggest that cultured human ciliary epithelial cells are able to metabolize estrogen, androgen and progesterone, and that 17HSD2 and 7 in these cells are sex steroid hormone-responsive genes and 17HSD7 is responsible to keep on intra/paracrine estrogenic milieu.     

Fibroblast growth factor 8b causes progressive stromal and epithelial changes in the epididymis and degeneration of the seminiferous epithelium in the testis of transgenic mice

Transgenic (Tg) mice expressing human fibroblast growth factor 8b (FGF8-b) under the probasin promoter (Tg [Pbsn-FGF8] L2-L5Elo; hereafter referred to as FGF8-b-Tg) were shown to produce FGF8-b at high levels in the prostate and epididymis and at lower levels in the testis. The present study examined the effects of FGF8-b expression on the epididymis and testis. In old (age, >6 mo) FGF8-b-Tg mice, epididymides were frequently enlarged, with epithelial and stromal hypercellularity progressing upon aging to epithelial dysplasia and malignant transformation of stroma. In addition, oligospermia, dilatation of the duct, and inflammation were frequently observed in the epididymides. In association with the epididymal changes, some FGF8-b-Tg mice presented a degenerative seminiferous epithelium of the testis. Consistent with this observation, infertile males were found in two FGF8-b-Tg mouse lines. Masson trichrome staining and immunohistochemical analysis of smooth muscle actin, laminin, and androgen receptor revealed that changes in the epididymal stroma closely resembled those previously found in the prostates of the FGF8-b-Tg mice. Genes previously found to be upregulated in the prostate of FGF8-b-Tg mice, such as osteopontin (Spp1) connective tissue growth factor (Ctgf), apolipoprotein D (Apod), and FGF receptor 1c (Fgfr1-c), were also upregulated in the epididymides, suggesting that similar molecular mechanisms were active in both tissues. However, unlike in the prostate, the changes in the epididymal epithelium of the FGF8-b-Tg mice did not progress into invasive carcinoma. The results suggest that prolonged and enhanced FGF signaling induces dramatic changes in the epididymis and testis that lead to infertility in a portion of the FGF8-b-Tg males.     

Midsummer spatial variation in methane efflux from stands of littoral vegetation in a boreal meso-eutrophic lake

1. Spatial variation of methane (CH₄) efflux from the littoral zone of a meso‐eutrophic boreal lake was studied with a closed‐chamber technique for three summer days in 22 vegetation stands, consisting of three emergent and three floating‐leaved species. 2. Between‐species differences in CH₄ emission were significant. The highest emissions were measured from the emergent Phragmites australis stands (0.5–1.7 mmol m^?2 h^?1), followed by Schoenoplectus lacustris > Equisetum fluviatile > Nuphar lutea > Sparganium gramineum > Potamogeton natans. Within‐species differences between stands were not significant. 3. In P. australis stands, the stand‐specific mean CH₄ emission was significantly correlated with solar radiation, probably indicating the role of effective pressurised ventilation on CH₄ fluxes. The proportion of net primary production emitted as CH₄ was significantly higher in P. australis stands (7.4%) than in stands of S. lacustris and E. fluviatile (both 0.5%). 4. In N. lutea stands, CH₄ efflux was negatively correlated with the mean fetch and positively with the percentage cover of leaves on the water surface. There were no differences in CH₄ efflux between intact N. lutea leaves and those grazed by coleopteran Galerucella nymphaeae. In S. graminaeum and P. natans stands, CH₄ effluxes were not related to any of the measured environmental variables. 5. For all vegetation stands, the biomass above water level explained about 60% of the observed spatial variation in CH₄ emission, indicating the important role of plants as gas conduits and producers of substrates for methanogens in the anoxic sediment.