Microorganisms of Lake Baikal and Lake Nyasa as Indicators of Anthropogenic Influence: Prospects for Use in Biotechnology

Restriction endonucleases (RENs) were detected in 650 microbial strains isolated from water columns and bottom sediments of deep rift lakes, Baikal (Russia) and Nyasa (Southeastern Africa). They enzymes included unique (Fan I, Aca I, and Sse 91) and very rare (Bsi I, and Cci N I) species not typical of aquatic ecosystems. Water columns, deep cores, and bottom sediments of pure areas of the lakes contained no microorganisms with new RENs. Thus, the inshore areas of Lake Baikal, having been exposed to anthropogenic influences, may contain mutant bacterial strains expressing RENs that have not been described previously.     

A new DNA methyltransferase M.BstC8I forms 5'-G(M5C)NNGC-3'. Studying of restriction endonuclease sensitivity to M.BstC8I-methylation

Bacillus stearothermophilus C8 was grown up on the Luria agar at 37 degrees C. A new DNA-methylase was determined in cellular lysate. The methylation of the DNAs of bacteriophages lambda and T7 in the region of 5'-G(m5C)NNGC-3' blocked the activity of BstC8I. Specificity of M.BstC8I was analyzed on methylated lambda DNA. For this purpose, we used computer modeling and the data on the sensitivity of restrictases BstC8I, BsuRI, AjnI, and PvuII to methylation. The sensitivity of some restrictases to new methylation was studied. The results may be used for DNA methylation studying.     

Determination of substrate specificity of restriction endonuclease FauI

The recognition sequence and cleavage point of restriction endonuclease FauI have been determined as 5'-CCCGC(4/6). Not being isoschisomer of any known restriction endonuclease, this enzyme may be used in genetic engineering.     

BtrI, a novel restriction endonuclease, recognises the non-palindromic sequence 5′-CACGTC(-3/-3)-3′

The recognition sequence and cleavage positions of a new restriction endonuclease BtrI isolated from Bacillus stearothermophilus SE-U62 have been determined. BtrI belongs to a rare type IIQ of restriction endonucleases, which recognise non-palindromic nucleotide sequences and cleave DNA symmetrically within them.     

Concentration of caveolin-3 at the neuromuscular junction in young and old rat skeletal muscle fibers.

Caveolin-3, a muscle-specific member of the caveolin family, is strongly localized to the neuromuscular junction (NMJ) in adult rat muscle fibers, where it co-localizes with alpha-bungarotoxin staining. In 24-month-old rats, less distinct staining corresponds with the normal aging changes in the NMJ. After denervation, the pattern and intensity of staining begin to break up as early as 3 days, and by 10 days little staining remains. The functional implications of this concentration of caveolin-3 at the NMJ remain obscure, but it is possible that its absence could account for some of the phenotypic characteristics of individuals with caveolin-3 mutations.     

Varied diet and opportunistic foraging in the Ethiopian Bush-crow Zavattariornis stresemanni,an Endangered generalist

The Ethiopian Bush-crow Zavattariornis stresemanni is an endangered, co-operatively breeding southern Ethiopian endemic with a remarkably restricted range (c. 6 000 km²). The species’ range was recently found to be almost perfectly predicted by an envelope of cooler, drier and more seasonal climate than surrounding areas, but the proximate determinants of this range restriction remain unclear. We assessed whether specialisation in diet or foraging may restrict the range of the species by conducting foraging watches to determine prey composition, augmented by observations of opportunistic foraging techniques, and by comparing our results to previously published information on diet. Prey composition comprised a range of arthropods, such as insect larvae (62.7%), beetles (Coleoptera) (15.6%), and grasshoppers and crickets (Orthoptera) (11.8%). Prey was primarily obtained by pecks above ground (74.2%) but also frequently dug up (23.8%). Prey capture was most successful during pecks and we also found chicks were preferentially fed larger prey items over smaller ones by adults. We documented opportunistic behaviours such as nest-raiding and ox-pecking. Diet and foraging are varied and unspecialised, and therefore do not appear to explain the restricted range of the Ethiopian Bush-crow.     

Type II SsrI restriction endonuclease from Staphylococcus saprophyticus

The recognition sequence and cleavage site for restriction endonuclease SsrI have been determined, the latter being 5'-GTT decreases AAC-3'. The enzyme was isolated from Staphylococcus saprophyticus strain and may be used in DNA investigation instead of its isoshizomer HpaI.     

Selective regulation of arterial branching morphogenesis by synectin

Branching morphogenesis is a key process in the formation of vascular networks. To date, little is known regarding the molecular events regulating this process. We investigated the involvement of synectin in this process. In zebrafish embryos, synectin knockdown resulted in a hypoplastic dorsal aorta and hypobranched, stunted, and thin intersomitic vessels due to impaired migration and proliferation of angioblasts and arterial endothelial cells while not affecting venous development. Synectin(-/-) mice demonstrated decreased body and organ size, reduced numbers of arteries, and an altered pattern of arterial branching in multiple vascular beds while the venous system remained normal. Murine synectin(-/-) primary arterial, but not venous, endothelial cells showed decreased in vitro tube formation, migration, and proliferation and impaired polarization due to abnormal localization of activated Rac1. We conclude that synectin is involved in selective regulation of arterial, but not venous, growth and branching morphogenesis and that Rac1 plays an important role in this process.