Lachnospira pectinoschiza sp. nov., an Anaerobic Pectinophile from the Pig Intestine

Pectinophiles are bacteria that utilize pectin and only a few related compounds as substrates. Obligately anaerobic pectinophiles have been isolated from the intestinal tracts and gingivae of humans and from the rumina of cattle. We isolated three strains of pectinophilic bacteria from colonic contents of pigs but were unable to isolate pectinophiles from the rumen contents of four sheep, even when the animals were fed a high-pectin diet. The pectinophiles isolated from pigs were strictly anaerobic, motile, gram-positive rods (0.36 to 0.56 by 2.4 to 3.1 μm). Pectin, polygalacturonic acid, and gluconate were the only substrates that supported rapid growth. All three strains grew slowly on either lactose or cellobiose and fermented fructose after a lag of several days. Pectin was degraded by means of an extracellular pectin methylesterase and a Ca2+-dependent exopectate lyase. A comparison of the 16S rRNA sequences of these isolates with the 16S rRNA sequences of other gram-positive bacteria revealed a specific relationship with Lachnospira multipara (level of similarity, 94%). The Gram reaction, formation of spore-like structures, and the utilization of lactose and cellobiose differentiated the pig isolates from previously described pectinophiles. The pig isolates represent a previously undescribed species of the genus Lachnospira, for which we propose the name Lachnospira pectinoschiza

In-situ measurements of the optical absorption of dioxythiophene-based conjugated polymers

Conjugated polymers can be reversibly doped by electrochemical means. This doping introduces new sub-bandgap optical absorption bands in the polymer while decreasing the bandgap absorption. To study this behavior, we have prepared an electrochemical cell allowing measurements of the optical properties of the polymer. The cell consists of a thin polymer film deposited on gold-coated Mylar behind which is another polymer that serves as a counterelectrode. An infrared transparent window protects the upper polymer from ambient air. By adding a gel electrolyte and making electrical connections to the polymer-on-gold films, one may study electrochromism in a wide spectral range. As the cell voltage (the potential difference between the two electrodes) changes, the doping level of the conjugated polymer films is changed reversibly. Our experiments address electrochromism in poly(3,4-ethylene-dioxy-thiophene) (PEDOT) and poly(3,4-dimethyl-propylene-dioxy-thiophene) (PProDOT-Me$_2$). This closed electrochemical cell allows the study of the doping induced sub-bandgap features (polaronic and bipolaronic modes) in these easily oxidized and highly redox switchable polymers. We also study the changes in cell spectra as a function of polymer thickness and investigate strategies to obtain cleaner spectra, minimizing the contributions of water and gel electrolyte features

Piliation of Invasive Streptococcus pneumoniae Isolates in the Era before Pneumococcal Conjugate Vaccine Introduction in Malawi

The pneumococcal pilus has been shown to be an important determinant of adhesion and virulence in mouse models of colonization, pneumonia, and bacteremia. A pilus is capable of inducing protective immunity, supporting its inclusion in next-generation pneumococcal protein vaccine formulations. Whether this vaccine target is common among pneumococci in sub-Saharan Africa is uncertain. To define the prevalence and genetic diversity of type I and II pili among invasive pneumococci in Malawi prior to the introduction of the 13-valent pneumococcal conjugate vaccine (PCV13) into routine childhood immunization, we examined 188 Streptococcus pneumoniae isolates collected between 2002 and 2008 (17% serotype 1). In this region of high disease burden, we found a low frequency of invasive piliated pneumococci (14%) and pilus gene sequence diversity similar to that seen previously in multiple global pneumococcal lineages. All common serotypes with pilus were covered by PCV13 and so we predict that pilus prevalence will be reduced in the Malawian pneumococcal population after PCV13 introduction

Scheduling language and algorithm development study. Volume 3: Detailed functional specifications for the language and module library

The detailed functional specifications presented are written as requirements for software implementation of the language and the program modules, and are aimed at a specific audience

Therapeutic use of a receptor mimic probiotic reduces intestinal Shiga toxin levels in a piglet model of hemolytic uremic syndrome

BACKGROUND: Hemolytic uremic syndrome (HUS) is a systemic and potentially fatal complication of gastroenteritis secondary to Shiga toxin-producing enterohemorrhagic Escherichia coli (EHEC) infection characterized by microangiopathic hemolytic anemia, thrombocytopenia, and acute renal damage. Shiga toxin (Stx), the toxin principle in HUS, is produced locally within the gut following EHEC colonization and is disseminated via the vasculature. Clinical development of HUS currently has no effective treatment and is a leading cause of renal failure in children. Novel post-exposure therapies are currently needed for HUS; therefore, the purpose of this study was to investigate the efficacy of a Stx receptor mimic probiotic in a porcine model of HUS. Edema disease, an infection of swine caused by host adapted Shiga toxin-producing Escherichia coli (STEC) and mediated by Shiga toxin 2e (Stx2e), shares many pathogenic similarities to HUS. In this study, three-week old piglets were inoculated with STEC and 24 hours later treated twice daily with a probiotic expressing an oligosaccharide receptor mimic for Stx2e to determine if the probiotic could reduce intestinal toxin levels. METHODS: Piglets were orally inoculated with 10(10) CFU of STEC strain S1191 eight days after weaning. Beginning day 1 post-inoculation, piglets were treated orally twice daily with 5 × 10(11) CFU of either the receptor mimic probiotic or a sham probiotic for 10 days. Intestinal Stx2e levels were assessed daily via Vero cell assay. The efficacy of the probiotic at reducing intestinal Stx2e, vascular lesions, and clinical disease was evaluated with repeated measures ANOVA and Fisher's exact test as appropriate. RESULTS: The probiotic significantly reduced intestinal Stx2e, as reflected by decreased fecal toxin titers on days 3-8 post-inoculation (p < 0.01). Despite this reduction in intestinal toxin levels, however, the probiotic failed to reduce the incidence of vascular necrosis in target organs and had no effect on clinical disease. CONCLUSIONS: The data suggest that post-exposure treatment with a Stx-binding probiotic is effective in reducing intestinal toxin burden. Future studies could target this approach for possible development of post-exposure interventions.Shannon J Hostetter, Amy F Helgerson, James C Paton, Adrienne W Paton, and Nancy A Cornic