Solute transport, bacterial

Johnson, K.D., Hofte, H. Chrispeels, M.J. (1990). An intrinsic tonoplast protein of protein storage vacuoles in seeds is structurally related to a bacterial solute transporter (GlpF). The Plant Cell 2, 525-32. 

Aspects of four energy-transducing systems which can play an important role in bacterial energy metabolism will be discussed electron-transfer systems, the, Mg -activated ATPase complex, bacteriorhodopsin and secondary solute transport... 

Ajrfj+ = A P + Z pH where Z = 2.3 RT/ F The proton electrochemical potential (A Xjj+) difference across the coupled (energetically linked) plasma membrane in phototrophic bacteria plays an essential role in photophosphorylation and solute transport into bacterial cells. Therefore, the exact measurements of these quantities are required for studies of the mechanism of energy transduction. It was, for example, shown that R.ruhrum chrom-atophores, associated with a phospholipid-impregnated filter,... 

The Major Facilitator Superfamily (MFS) [95-97] is the largest secondary transporter family known in the genomes sequenced to date [98], These polytopic integral membrane proteins enable the transport of a wide range of solutes, including amino acids, sugars, ions, and toxins. Medically relevant members of the family include the bacterial efflux pumps associated with... 

The bacterial phosphoenolpyruvate (PEP)-dependent carbohydrate phosphotransferase systems (PTS) are characterised by their unique mechanism of group translocation. The transported solute is chemically modified (i.e. phos-phorylated) during the process (for comprehensive reviews see [151,152] and... 

Microbes are ubiquitous in the subsurface environment and as such may play an important role in groundwater solute behavior. Microbes in the subsurface can influence pollutants by solubility enhancement, precipitation, or transformation (biodegradation) of the pollutant species. Microbes in the groundwater can act as colloids or participate in the processes of colloid formation. Bacterial attachment to granular media can be reversible or irreversible and it has been suggested that extracellular enzymes are present in the system. Extracellular exudates (slimes) can be sloughed-off and act to transport sorbed materials [122]. The stimulation of bacterial growth in the subsurface maybe considered as in situ formation of colloids. 

Tissue electrodes [2, 3, 4, 5, 45,57], In these biosensors, a thin layer of tissue is attached to the internal sensor. The enzymic reactions taking place in the tissue liberate products sensed by the internal sensor. In the glutamine electrode [5, 45], a thick layer (about 0.05 mm) of porcine liver is used and in the adenosine-5 -monophosphate electrode [4], a layer of rabbit muscle tissue. In both cases, the ammonia gas probe is the indicator electrode. Various types of enzyme, bacterial and tissue electrodes were compared [2]. In an adenosine electrode a mixture of cells obtained from the outer (mucosal) side of a mouse small intestine was used [3j. The stability of all these electrodes increases in the presence of sodium azide in the solution that prevents bacterial decomposition of the tissue. In an electrode specific for the antidiuretic hormone [57], toad bladder is placed over the membrane of a sodium-sensitive glass electrode. In the presence of the antidiuretic hormone, sodium ions are transported through the bladder and the sodium electrode response depends on the hormone concentration. 

Manufacture of bacterial cellulose with desired shape Development of Kedem-Katchalsky equations of the transmembrane transport for binary nonhomogeneous non-electrolyte solutions Honeycomb patterned bacterial cellulose... 

We can now consider some typical nutrient solutes like amino acids and phosphate. Such molecules are ionized, which means that they would not readily cross the permeability barrier of a lipid bilayer. Permeability coefficients of liposome membranes to phosphate and amino acids have been determined [46] and were found to be in the range of 10 11 -10 12 cm/s, similar to ionic solutes such as sodium and chloride ions. From these figures one can estimate that if a primitive microorganism depended on passive transport of phosphate across a lipid bilayer composed of a typical phospholipid, it would require several years to accumulate phosphate sufficient to double its DNA content or pass through one cell cycle. In contrast, a modern bacterial cell can reproduce in as short a time as 20 min. 

In studies on transport in bacteria, another method for overcoming the problem of solute metabolism is to use bacterial mutants which will transport the solute but which lack one or more enzymes for metabolizing the solute. 

Whenever bacterial or fungal etiologies are suspected, ocular specimens for culture should ideally be plated directly on agar plates containing enriched or selective bacteriologic media. Commercially available transport media may not be sufficient for bacteria or fungi because most ocular specimens may contain diminutive quantities of fastidious microorganisms. However, transport solutions for viruses and chlamydia can effectively maintain... 

Most leaching described in the literature has followed the lines described above. Strongly basic ores, usually those containing abundant carbonate, are not well suited to bacterial leaching since a low pH is not as readily obtained as in other cases. For such ores, leaching with sodium carbonate solution has been used successfully, the uranium being transported as an anionic uranyl carbonate complex (Merritt, 1971). 

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