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Group B streptococcus (GBS) is a common asymptomatic colonizer in acidic vagina of pregnant women and can transmit to newborns, causing neonatal pneumonia and meningitis. Biofilm formation is often associated with bacterial colonization and pathogenesis. Little is known about GBS biofilm and the effect of environmental stimuli on their growth along with biofilm formation. The objective of this study was to investigate the survival and biofilm formation of GBS, isolated from pregnant women, in nutrient-limited medium under various pH conditions. Growth and survival experiments were determined by optical density and viable counts. Crystal violet staining, scanning electron microscopy, and atomic force microscopy (AFM) were used to analyze the capacity of biofilm production. Our results showed that GBS isolates proliferated with increasing pH with highest maximum specific growth rate (μ) at pH 6.5, but survived at pH 4.5 for longer than 48 h. Biofilm formation of the 80 GBS isolates at pH 4.5 was significantly higher than at pH 7.0. This difference was confirmed by two other methods. The low elastic modulus obtained from samples at pH 4.5 by AFM revealed the softness of biofilm; in contrast, little or no biofilm was measured at pH 7.0. Under acidic pH, the capability of biofilm formation of serotypes III and V showed statistically significant difference from serotypes Ia and Ib. Our finding suggested that survival and enhanced biofilm formation at vaginal pH are potentially advantageous for GBS in colonizing vagina and increase the risk of vaginosis and neonatal infection. [ABSTRACT FROM AUTHOR]

Septins are members of the GTPase superfamily, which has been implicated in diverse cellular functions including cytokinesis and morphogenesis. Septin 12 ( SEPT12) is a testis-specific gene critical for the terminal differentiation of male germ cells. We report the identification of two missense SEPT12 mutations, c.266C>T/p.Thr89Met and c.589G>A/p.Asp197Asn, in infertile men. Both mutations are located inside the GTPase domain and may alter the protein structure as suggested by in silico modeling. The p.Thr89Met mutation significantly reduced guanosine-5′-triphosphate (GTP) hydrolytic activity, and the p.Asp197Asn mutation (SEPT12D197N) interfered with GTP binding. Both mutant SEPT12 proteins restricted the filament formation of the wild-type SEPT12 in a dose-dependent manner. The patient carrying SEPT12D197N presented with oligoasthenozoospermia, whereas the SEPT12T89M patient had asthenoteratozoospermia. The characteristic sperm pathology of the SEPT12D197N patient included defective annulus with bent tail and loss of SEPT12 from the annulus of abnormal sperm. Our finding suggests loss-of-function mutations in SEPT12 disrupted sperm structural integrity by perturbing septin filament formation. Hum Mutat 33:710-719, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The effect of a water-soluble trimalonic acid derivative of fullerene, carboxyfullerene (C63(COOH)6), on the opening of blood-brain barrier (BBB) in Escherichia coli (E. coli)-induced meningitis was tested. In E. coli-induced meningitis model, the increase of BBB permeability was manifested in two distinct phases based on cytokine expression pattern and neutrophilic infiltration in B6 mice. An early increase in BBB permeability was occurred at 1–5 h post injection that could be blocked by either anti-TNF-αor anti-IL-1β antibodies. A late one (neutrophil-associated BBB opening) was manifested at 6–12 h that was inhibited by vinblastine pretreatment. Inhibition of the early E. coli-induced BBB opening blocked the development of the late one. Furthermore, the neutrophil-associated BBB opening (the late phase), but not cytokine- induced one (the early phase), was inhibited by a water-soluble carboxyfullerene. [ABSTRACT FROM AUTHOR]