Calpain activation is upstream of caspases in radiation-induced apoptosis

The molecular events involved in apoptosis induced by ionizing radiation remain unresolved. In this paper we show that the cleavage of fodrin to a 150 kDa fragment is an early proteolytic event in radiation-induced apoptosis in the Burkitts' Lymphoma cell line BL30A and requires 100 microM zVAD-fmk for inhibition. Caspases-1, -3, -6 and -7 were shown to cleave fodrin to the 150 kDa fragment in vitro and all were inhibited by 10 microM zVAD-fmk. We also show that the in vitro cleavage of fodrin by calpain is inhibited by 100 microM zVAD-fmk as was the calpain-mediated hydrolysis of casein. We demonstrate that calpain is activated within 15 min after radiation exposure, concomitant with the cleavage of fodrin to the 150 kDa fragment whereas caspase-3 is activated at 2 h correlating with the cleavage of fodrin to the 120 kDa fragment. These results support a role for calpain in the early phases of the radiation-induced apoptosis pathway, upstream of the caspases.     

Evolutionary variation in bacterial RNase P RNAs

Sequences encoding RNase P RNAs from representatives of the last remaining classical phyla of Bacteria have been determined, completing a general phylogenetic survey of RNase P RNA sequence and structure. This broad sampling of RNase P RNAs allows some refinement of the secondary structure, and reveals patterns in the evolutionary variation of sequences and secondary structures. Although the sequences range from 100 to <25% identical to one another, and although only 40 of the nucleotides are invariant, there is considerable conservation of the underlying core of the RNA sequence. RNase P RNAs, like group I intron RNAs but unlike ribosomal RNAs, transfer RNAs or other highly conserved RNAs, are quite variable in secondary structure outside of this conserved structural core. Conservative regions of the RNA evolve by substitution of apparently interchangeable alternative structures, rather than the insertion and deletion of helical elements that occurs in the more variable regions of the RNA. In a remarkable case of convergent molecular evolution, most of the unusual structural elements of type B RNase P RNAs of the low G+C Gram-positive Bacteria have evolved independently in Thermomicrobium roseum , a member of the green non-sulfur Bacteria.     

Parametric studies of free-electron laser nonlinear ponderomotivetrapping buckets

Experimental and computational studies of free-electron lasers (FELs) operating at high input powers have been undertaken. These studies constitute a novel method of investigating saturation and trapping effects in free-electron lasers. Experiments and simulations show that when the input radiation power is increased to levels comparable to output power, the energy that maximizes the FEL gain shifts upwards. This effect is directly related to the height of the FEL ponderomotive trapping bucket (see J.S. Wurtele et al., 1990). By parametrically surveying the extent of this energy shift the authors observe the nonlinear trapping bucket phenomenon     

Cloning and expression of a plasmid pBS195 gene, determining oxygenase activity, in Escherichia coli cells

Plasmid pBS195, detected in a strain of Lactobacillus sp. isolated from long-living persons, has a broad host range, including Gram-positive and Gram-negative microorganisms [1]. Plasmid-harboring colonies of the strain Escherichia coli HB101 give a color reaction with catechol. This indicates that genes mediating the activity of oxygenase are present in this plasmid. The high activity level of this enzyme, mediated by pBS195, and substrate specificity, which has not bee detected in any known metapyrocatechases, were found in cells of E. coli. Hybridization with a 32P-labeled fragment containing the NahC gene revealed a region of homology with a 1.6-kb EcoR I- BamH I fragment of plasmid pBS195. Deletion variants of this plasmid that lost oxygenase activity confirmed the location of the oxygenase gene in this region. The gene responsible for oxygenase activity in the plasmid was cloned on the pUC19 vector in E. coli cells. The expression of the cloned gene is controlled by the lac promoter of this vector. Physical, hybridization, and deletion analyses as well as analysis of polypeptides, which are synthesized in E. coli mini-cells, showed that this activity requires the participation of a polypeptide with molecular mass of 34 kDa.     

Role of local lymphatic stimulation in the prevention of early complications after stomach surgeries

Experiments were conducted on 120 albino rats and 16 dogs with the use of scanning and electron microscopy as well as the radionuclide method of microcirculation study to substantiate the method of regional lymphostimulation after operations on the stomach for the prevention of early postoperative complications. Some lymphagogues (lidase, heparin, procaine hydrochloride) were infused in the early postoperative period through a catheter introduced into the hepatoduodenal ligament. This zone is represented by a large group of lymph nodes receiving lymph from the stomach and the adjacent organs and the intercellular space of the hepatoduodenal ligament. The study showed that lymphostimulation improves the circulation of lymph and blood which are disturbed as the result of the operation and improves the local homeokinesis in the wall of the stomach after its resection and vagotomy. Lymphostimulation increases the resorption and transport activity of the lymphatic system and improves drainage of the edema fluid and the products of disturbed metabolism from the interstitium of the gastric mucosa. The results of using the method of regional lymphostimulation in 441 patients after various operations on the stomach for peptic ulcer showed the possibility of reducing the number of early postoperative complications, such as inadequacy of the sutures of the gastroduodeno--entero--anastomosis, anastomositis, infectious-inflammatory complications, and others.