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 possess channel proteins, some of which probably function to relieve osmotic stress. Amino acid uptake systems predominate over sugar and peptide cation symporters, and of the sugar uptake porters, those specific for oligosaccharides and glycosides often outnumber those for free sugars. About 10% of the total transport proteins are constituents of putative multidrug efflux pumps with Major Facilitator Superfamily (MFS)-type pumps (55%) being more prevalent than ATP-binding cassette (ABC)-type pumps (33%), which, however, usually greatly outnumber all other types. An exception to this generalization is Streptococcus thermophilus with 54% of its drug efflux pumps belonging to the ABC superfamily and 23% belonging each to the Multidrug/Oligosaccharide/Polysaccharide (MOP) superfamily and the MFS. These bacteria also display peptide efflux pumps that may function in intercellular signalling, and macromolecular efflux pumps, many of predictable specificities. Most of the bacteria analyzed have no pmf-coupled or transmembrane flow electron carriers. The one exception is Brevibacterium linens, which in addition to these carriers, also has transporters of several families not represented in the other ten bacteria examined. Comparisons with the genomes of organisms from other bacterial kingdoms revealed that lactic acid bacteria possess distinctive proportions of recognized transporter types (e.g., more porters specific for glycosides than reducing sugars). Some homologues of transporters identified had previously been identified only in Gram-negative bacteria or in eukaryotes. Our studies reveal unique characteristics of the lactic acid bacteria such as the universal presence of genes encoding mechanosensitive channels, competence systems and large numbers of sugar transporters of the phosphotransferase system. The analyses lead to important physiological predictions regarding the preferred signalling and metabolic activities of these industrially important bacteria.

Drought conditions in the Southwestern U. S. and other parts of the world, the potential future impacts of climate change and politically-charged decisions regarding the allocation of water resources continue to challenge the agricultural community to find ways to successfully grow necessary food crops using less irrigation water. In addition, in many parts of the U. S., high levels of certain salts render ground water supplies unusable for salt-sensitive crops. Salt accumulation in soil and in tissues can also be a problem when water conservation methods are applied. Methods that save water and counteract salt accumulation are needed. Historically, magnetic water treatment (MWT) has shown promise in addressing both concerns though results have been inconsistent and somewhat controversial. This study evaluated the effect of MWT on lettuce yield, photosynthetic activity and nutrient levels under various irrigation reduction regimes. In addition, Watermark soil moisture sensors from Irrometer were used to measure the matric potential of root-depth soil of MWT, and non-MWT plants under those same regimes. Results indicated that statistically significant increases in yield, total chlorophyll and concentrations of some macro and micro-nutrients in plants treated by MWT could be achieved while using significantly less water compared to non-MWT irrigation water. In addition, MWT may also help counteract the effect of harmful sodium buildup in plants when less irrigation water was used.

No abstract

Abstract:Magnetic water treatment devices (MWT), while attractive because of their safety, simplicity, environmental friendliness and effectiveness in agriculture have been difficult to assess scientifically because a single, generally accepted, repeatable and measurable indicator of their decree of impact on the physical properties of water, has not been discovered. Experimental results have shown that MWT offers many agricultural benefits and that magnetically-treated water can more easily penetrate various media such as membranes, which are generally considered excellent proxies for plant cell walls. This study evaluated how MWT changes permeability through a semi-permeable membrane, how that change is impacted by flow velocity and proposed membrane permeability as a reliable indicator of MWT effectiveness. Results obtained from this study indicated that MWT changed permeability through a semi-permeable membrane and these changes depended on water flow velocity. Results further indicated that the permeability differential in the MWT treatment group decreased by almost 9% at low-flow velocities (laminar regime; Re<1000) to 2.3% at the high-flow velocities, compared to control (turbulent regime; Re>4000). At low-flow velocities, the electro-conductivity of MWT and the control group were statistically different at p ≤ 0.01. However, at higher-flow velocities, the difference between MWT and the control group was smaller and a statistically sufficient level was reached only at p ≤ 0.05 and p ≤ 0.10. The differences observed between the low, and high-flow velocity treatment groups was somewhat expected as high flow rates reduce the retention time of water in the treatment area and thus reduces the efficiency of magnetic treatment. These results also provide a clear indication that water has been impacted by MWT and demonstrate the degree that water has been impacted by MWT under various flow rates.