Rising sea levels and salinization of groundwater due to global climate change result in fast-dwindling sources of freshwater. Therefore, it is important to find alternatives to grow food crops and vegetables. Halophytes are naturally evolved salt-tolerant plants that are adapted to grow in environments that inhibit the growth of most glycophytic crop plants substantially.
View Article and Find Full Text PDFHalophytes, salt-tolerant plants, are a source of valuable secondary metabolites with potential economic value. The steady-state pools of many stress-related metabolites are already enhanced in halophytes when compared with glycophytes, but growth under conditions away from the optimum can induce stress and consequently result in changes to secondary metabolites such as antioxidants. However, direct evidence for increasing the concentration of valuable secondary metabolites as a consequence of altering the salinity of the growing environment still remains equivocal.
View Article and Find Full Text PDFSalt tolerance of halophytes relies on several strategies, among them, the production of species-specific secondary metabolites. Chemically, a broad variety of secondary compounds of economic interest is present in halophytes. Several of these secondary compounds are restricted to halophytic species or are found in higher concentrations than in glycophytes.
View Article and Find Full Text PDFHelicobacter pylori resists gastric acidity by modulating the proton-gated urea channel UreI, allowing for pH(out)-dependent regulation of urea access to intrabacterial urease. We employed pH- and Ca(2+)-sensitive fluorescent dyes and confocal microscopy to determine the location, rate, and magnitude of pH changes in an H. pylori-AGS cell coculture model, comparing wild-type bacteria with nonpolar ureI-deletion strains (ureI-ve).
View Article and Find Full Text PDFureI encodes an inner membrane protein of Helicobacter pylori. The role of the bacterial inner membrane and UreI in acid protection and regulation of cytoplasmic urease activity in the gastric microorganism was studied. The irreversible inhibition of urease when the organism was exposed to a protonophore (3,3',4', 5-tetrachlorsalicylanide; TCS) at acidic pH showed that the inner membrane protected urease from acid.
View Article and Find Full Text PDFThe only experimental data available on the membrane topology of transition metal ATPases are from in vitro studies on two distinct P-type ATPases (CadA and CopA) of a gastric bacterium, Helicobacter pylori, both postulated to contain eight transmembrane domains (H1 to H8). In this study, H. pylori CadA ATPase was subjected to analysis of membrane topology in vivo by expression of ATPase-alkaline phosphatase (AP) hybrid proteins in Escherichia coli using a novel vector, pBADphoA.
View Article and Find Full Text PDFCloning and sequencing of an approximately 6.0-kb chromosomal DNA fragment from Helicobacter felis revealed five complete open reading frames. The deduced amino acid sequence of one ORF exhibited sequence similarity to the FtsH protein, an ATP-dependent metalloprotease, from various bacterial species.
View Article and Find Full Text PDFSouthern blot screening of a genomic Helicobacter pylori library was employed to find a P type ATPase using a mixture of 16 DNA oligonucleotides coding for the DKTGT(I/L)T consensus sequence specific for the phosphorylation site of this family of ATPases. A positive clone, pRH439, was isolated and sequenced. The inserted 3.
View Article and Find Full Text PDFThis study examines whether the regular use of sugar-free chewing gum can improve oral hygiene and therefore reduce the risk of caries. During a four-week test, twenty subjects chewed a piece of gum twice a day for thirty minutes after meals. At the start, after two weeks, and at the end of the test period, the plaque and gingiva indices were recorded and the buffer capacity and secretion rate of the saliva determined.
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