ABCD2 is abundant in adipose tissue and opposes the accumulation of dietary erucic acid (C22:1) in fat

The ATP binding cassette transporter, ABCD2 (D2), is a peroxisomal protein whose mRNA has been detected in the adrenal, brain, liver, and fat. Although the role of this transporter in neural tissues has been studied, its function in adipose tissue remains unexplored. The level of immunoreactive D2 in epididymal fat is >50-fold of that found in brain or adrenal. D2 is highly enriched in adipocytes and is upregulated during adipogenesis but is not essential for adipocyte differentiation or lipid accumulation in day 13.5 mouse embryonic fibroblasts isolated from D2-deficient (D2^−/−) mice. Although no differences were appreciated in differentiation percentage, total lipid accumulation was greater in D2^−/− adipocytes compared with the wild type. These results were consistent with in vivo observations in which no significant differences in adiposity or adipocyte diameter between wild-type and D2^−/− mice were observed. D2^−/− adipose tissue showed an increase in the abundance of 20:1 and 22:1 fatty acids. When mice were challenged with a diet enriched in erucic acid (22:1), this lipid accumulated in the adipose tissue in a gene-dosage-dependent manner. In conclusion, D2 is a sterol regulatory element binding protein target gene that is highly abundant in fat and opposes the accumulation of dietary lipids generally absent from the triglyceride storage pool within adipose tissue.     

A bioreactor test system to mimic the biological and mechanical environment of oral soft tissues and to evaluate substitutes for connective tissue grafts

Gingival cells of the oral connective tissue are exposed to complex mechanical forces during mastication, speech, tooth movement and orthodontic treatments. Especially during wound healing following surgical procedures, internal and external forces may occur, creating pressure upon the newly formed tissue. This clinical situation has to be considered when developing biomaterials to augment soft tissue in the oral cavity. In order to pre‐evaluate a collagen sponge intended to serve as a substitute for autogenous connective tissue grafts (CTGs), a dynamic bioreactor system was developed. Pressure and shear forces can be applied in this bioreactor in addition to a constant medium perfusion to cell‐material constructs. Three‐dimensional volume changes and stiffness of the matrices were analyzed. In addition, cell responses such as cell vitality and extracellular matrix (ECM) production were investigated. The number of metabolic active cells constantly increased under fully dynamic culture conditions. The sponges remained elastic even after mechanical forces were applied for 14 days. Analysis of collagen type I and fibronectin revealed a statistically significant accumulation of these ECM molecules (P < 0.05–0.001) when compared to static cultures. An increased expression of tenascin‐c, indicating tissue remodeling processes, was observed under dynamic conditions only. The results indicate that the tested in vitro cell culture system was able to mimic both the biological and mechanical environments of the clinical situation in a healing wound. Biotechnol. Bioeng. 2010;107: 1029–1039. © 2010 Wiley Periodicals, Inc.     

Lactobacillus strains isolated from the vaginal microbiota of healthy women inhibit Prevotella bivia and Gardnerella vaginalis in coculture and cell culture

The purpose of this study was to investigate how human vaginal isolates of Lactobacillus acidophilus, Lactobacillus jensenii, Lactobacillus gasseri and Lactobacillus crispatus inhibit the vaginosis-associated pathogens Gardnerella vaginalis and Prevotella bivia. Results show that all the strains in coculture condition reduced the viability of G. vaginalis and P. bivia, but with differing degrees of efficacy. The treatment of G. vaginalis- and P. bivia-infected cultured human cervix epithelial HeLa cells with L. gasseri strain KS120.1 culture or cell-free culture supernatant (CFCS) results in the killing of the pathogens that are adhering to the cells. The mechanism of the killing activity is not attributable to low pH and the presence of lactic acid alone, but rather to the presence of hydrogen peroxide and proteolytic enzyme-resistant compound(s) present in the CFCSs. In addition, coculture of G. vaginalis or P. bivia with L. gasseri KS120.1 culture or KS120.1 bacteria results in inhibition of the adhesion of the pathogens onto HeLa cells.     

Postnatal allometry of the skeleton in Tupaia glis (Scandentia: Tupaiidae) and Galea musteloides (Rodentia: Caviidae)--a test of the three-segment limb hypothesis

During the evolution of therian mammals, the two-segmented, sprawled tetrapod limbs were transformed into three-segmented limbs in parasagittal zig-zag configuration (three-segment limb hypothesis). As a consequence, the functional correspondence of limb segments has changed (now: scapula to thigh, upper arm to shank, fore arm plus hand to foot). Therefore, the scapula was taken into account in the current study of the postnatal growth of the postcranial skeleton in two small mammalian species (Tupaia glis, Galea musteloides). Comparisons were made between the functionally equivalent elements and not in the traditional way between serially homologous segments. This study presents a test of the three-segment limb hypothesis which predicts a greater ontogenetic congruence in the functionally equivalent elements in fore and hind limbs than in the serially homologous elements. A growth sequence, with decreasing regression coefficients from proximal to distal, was observed in both species under study. This proximo-distal growth sequence is assumed to be ancestral in the ontogeny of eutherian mammals. Different reproductive modes have evolved within eutherian mammals. To test the influence of different life histories on ontogenetic scaling during postnatal growth, one species with altricial juveniles (Tupaia glis) assumed to be the ancestral mode of development for eutherians and one species with derived, precocial young (Galea musteloides) were selected. The growth series covered postnatal development from the first successive steps with a lifted belly to the adult locomotory pattern; thus, functionally equivalent developmental stages were compared. The higher number of allometrically positive or isometrically growing segments in the altricial mammalian species was interpreted as a remnant of the fast growth period in the nest without great locomotor demands, and the clearly negative allometry in nearly all segments in the precocial young was interpreted as a response to the demand on early locomotor activity. Different life histories seem to have a strong influence on postnatal ontogenetic scaling; the effects of the developmental differences are still observable when comparing adults of the two species.     

In vitro antibacterial activity of Lactobacillus helveticus strain KS300 against diarrhoeagenic, uropathogenic and vaginosis-associated bacteria

AIMS: The purpose of this study was to investigate in vitro the antibacterial activity of the Lactobacillus helveticus strain KS300 against vaginosis-associated bacteria including Gardnerella vaginalis and Prevotella bivia, uropathogenic Escherichia coli, and diarrhoeagenic Salmonella enterica serovar Typhimurium. METHODS AND RESULTS: The KS300 strain inhibited the growth of G. vaginalis, P. bivia, S. typhimurium, and pathogenic E. coli. After direct co-culture, data show that the Lactobacillus strain decreased the viability of G. vaginalis, P. bivia, S. typhimurium, and pathogenic E. coli. The adhering KS300 strain inhibited the adhesion of G. vaginalis DSM 4944 and uropathogenic Dr-positive E. coli IH11128 onto HeLa cells. Moreover, the KS300 strain inhibited the internalization of uropathogenic Dr-positive E. coli IH11128 within HeLa cells and S. typhimurium SL1344 within Caco-2/TC7 cells. CONCLUSIONS: The findings demonstrate that L. helveticus strain KS300 is adhesive onto cultured human cells and has antagonistic activities against vaginosis-associated, uropathogenic and diarrhoeagenic pathogens. SIGNIFICANCE AND IMPACT OF THE STUDY: Adhering L. helveticus strain KS300 is a potential probiotic strain displaying a strain-specific array of in vitro antibacterial activities.     

Development of a process for the production of the anticancer lead compound pleurotin by fermentation of Hohenbuehelia atrocaerulea

Pleurotin is a naphthoquinone antibiotic originally isolated from Pleurotus griseus. Two pleurotin producing strains of Hohenbuehelia atrocaerulea have been identified, which, on solid substrate fermentation for 2 months yield 1-2 mg/l of the antibiotic. Described here is the lengthy developmental process which resulted in a production protocol being developed which reliably yields pleurotin from liquid fermentation at >300 mg/l. Critical to obtaining this increase in titer was inclusion in the media of an aqueous extract of alder wood.     

A critical beta6-beta7 loop in the pleckstrin homology domain of ceramide kinase

CerK (ceramide kinase) produces ceramide 1-phosphate, a sphingophospholipid with recognized signalling properties. It localizes to the Golgi complex and fractionates essentially between detergent-soluble and -insoluble fractions; however, the determinants are unknown. Here, we made a detailed mutagenesis study of the N-terminal PH domain (pleckstrin homology domain) of CerK, based on modelling, and identified key positively charged amino acid residues within an unusual motif in the loop interconnecting beta-strands 6 and 7. These residues are critical for CerK membrane association and polyphosphoinositide binding and activity. Their mutagenesis results in increased thermolability, sensitivity to proteolysis, reduced apparent molecular mass as well as propensity of the recombinant mutant protein to aggregate, indicating that this loop impacts the overall conformation of the CerK protein. This is in contrast with most PH domains whose function strongly relies on charges located in the beta1-beta2 loop.     

Culture-independent characterization of the digestive-tract microbiota of the medicinal leech reveals a tripartite symbiosis

Culture-based studies of the microbial community within the gut of the medicinal leech have typically been focused on various Aeromonas species, which were believed to be the sole symbiont of the leech digestive tract. In this study, analysis of 16S rRNA gene clone libraries confirmed the presence of Aeromonas veronii and revealed a second symbiont, clone PW3, a novel member of the Rikenellaceae, within the crop, a large compartment where ingested blood is stored prior to digestion. The diversity of the bacterial community in the leech intestinum was determined, and additional symbionts were detected, including members of the alpha-, gamma-, and delta-Proteobacteria, Fusobacteria, Firmicutes, and Bacteroidetes. The relative abundances of the clones suggested that A. veronii and the novel clone, PW3, also dominate the intestinum community, while other clones, representing transient organisms, were typically present in low numbers. The identities of these transients varied greatly between individual leeches. Neither time after feeding nor feeding on defibrinated blood caused a change in identity of the dominant members of the microbial communities. Terminal restriction fragment length polymorphism analysis was used to verify that the results from the clone libraries were representative of a larger data set. The presence of a two-member bacterial community in the crop provides a unique opportunity to investigate both symbiont-symbiont and symbiont-host interactions in a natural model of digestive-tract associations.