The insolubility of Fe3+ necessitates special mechanisms for iron acquisition in most organisms. Bacteria use siderophores to chelate Fe3+ and iron in heme, hemoglobin, transferrin and lactoferrin, and employ novel mechanisms for receptor-dependent iron transport and iron-regulated gene expression. These mechanisms involve transfer of energy from the cytoplasmic membrane to the outer membrane t...

Although the use of microbial tracers has been instrumental in developing a better understanding of groundwater movement in many types of aquifers (1, 17, 34, 141, 149, 189, 190, 239), the importance of studying the transport behavior of the microorganisms themselves is now very apparent. This is due largely to an increasing dependence on limited and fragile groundwater resources. In particular...

Active transport across the outer membrane in gram-negative bacteria requires the energy that is generated by the proton motive force in the inner membrane. This energy is transduced to the outer membrane by the TonB protein in complex with the proteins ExbB and ExbD. In the pathogen Vibrio anguillarum we have identified two TonB systems, TonB1 and TonB2, the latter is used for ferric-anguibact...

Endotoxin, also referred to as lipopolysaccharide (LPS), can stimulate localized or systemic inflammation via the activation of pattern recognition receptors. Additionally, endotoxin and inflammation can regulate intestinal epithelial function by altering integrity, nutrient transport, and utilization. The gastrointestinal tract is a large reservoir of both gram-positive and gram-negative bacte...

The high concentration of swine production in southeastern North Carolina generates public health concerns regarding the potential transport of pathogens from these production systems to nearby surface waters. The microbial source tracking (MST) tool, antibiotic resistance analysis (ARA), was used to identify sources of E. coli in a segment of Six Runs Creek in Sampson County, North Carolina. A...

Escherichia coli cells carrying fosfomycin resistance plasmids were able to take up fosfomycin from the medium to the same extent as plasmid-free bacteria. The antibiotic entered the plasmid-harboring cells by means of the glpT and uhp transport systems, as is the case with susceptible bacteria. Active fosfomycin could be detected in soluble extracts of cells which had previously been incubated...

The genomes of eleven Gram-positive bacteria that are important for human health and the food industry, nine low G+C lactic acid bacteria and two high G+C Gram-positive organisms, were analyzed for their complement of genes encoding transport proteins. Thirteen to 18% of their genes encode transport proteins, larger percentages than observed for most other bacteria. All of these bacteria posses...

Burkholderia spp. that degrade phthalate have an ABC transporter-type phthalate transport system (OphFGH) and a specific porin (OphP) in addition to a permease-type phthalate transporter (OphD). OphFGH has a lower K(m) and higher V(max) than OphD, which affects how the bacteria grow. OphP is involved in both mechanisms of transport.

Growth of Bacteria and Archaea has been observed at temperatures up to 95 and 110 degrees C, respectively. These thermophiles are adapted to environments of high temperature by changes in the membrane lipid composition, higher thermostabilities of the (membrane) proteins, higher turnover rates of the energy transducing enzymes, and/or the (exclusive) use of sodium-ions rather than protons as co...