Effects of physical training on several glycolytic enzymes in rat heart

In response to a program of daily swimming for 16 weeks, the activities of pyruvate kinase and lactate dehydrogenase increased significantly in the hearts of young male rats. The isozyme composition in M of cardiac lactate dehydrogenase increased from 28.5 to 32.7% in the trained animals. Phosphofructokinase activity and glycogen content were unchanged. The hearts of the exercising animals were 28% heavier than those of sedentary paired weight controls.     

Effects of various agents on the R bodies of certain bacteria

We have shown that urea and temperature affect the unrolling of the R bodies from the bacteria Caedibacter taeniospiralis, Pseudomonas taeniospiralis and Pseudomonas avenae. The R bodies of P. taeniospiralis are not, however, affected by pH changes nor by EDTA or EGTA unlike the other two types of R body. Antibodies prepared against the R bodies of C. taeniospiralis have been shown, following gold-labelling and electron microscopy, to be specific for the proteins of the homologous R body. Pre-treatment of R bodies with pronase or sodium periodate had no effect on these reactions.     

Effects of physical training on several glycolytic enzymes in rat heart.

In response to a program of daily swimming for 16 weeks, the activities of pyruvate kinase and lactate dehydrogenase increased significantly in the hearts of young male rats. The isozyme composition in M of cardial lactate dehydrogenase increased from 28.5 to 32.7% in the trained animals. Phosphofructokinase activity and glycogen content were unchanged. The hearts of the exercising animals were 28% heavier than those of sedentary paired weight controls.     

Flagellin treatment protects against chemicals, bacteria, viruses, and radiation

Sudden exposure of human populations to chemicals, pathogens, or radiation has the potential to result in substantial morbidity. A potential means of rapidly protecting such populations might be to activate innate host defense pathways, which can provide broad protection against a variety of insults. However, innate immune activators can, by themselves, result in severe inflammatory pathology, which in large part is driven by hemopoietic-derived cytokines such as TNF-alpha. We reasoned that, because it preferentially activates epithelial cells, the TLR5 agonist flagellin might not induce severe inflammatory pathology and yet be an ideal agent to provide such non-specific protection, particularly at the mucosal surfaces that serve as a front line of host defense. In accordance, we observed that systemic treatment of mice with purified flagellin did not induce the serologic, histopathologic, and clinical hallmarks of inflammation that are induced by LPS but yet protected mice against chemicals, pathogens, and ionizing radiation. Flagellin-elicited radioprotection required TLR5, the TLR signaling adaptor MyD88, and was effective if given between 2 h before to 4 h after exposure to irradiation. Flagellin-elicited radioprotection was, in part, mediated via effects on cells in bone marrow but yet rescued mortality without a pronounced rescue of radiation-induced anemia or leukopenia. Thus, systemic administration of flagellin may be a relatively safe means of providing temporary non-specific protection against a variety of challenges.     

Sortase enzymes in Gram-positive bacteria

In Gram-positive bacteria proteins are displayed on the cell surface using sortase enzymes. These cysteine transpeptidases join proteins bearing an appropriate sorting signal to strategically positioned amino groups on the cell surface. Working alone, or in concert with other enzymes, sortases either attach proteins to the cross-bridge peptide of the cell wall or they link proteins together to form pili. Because surface proteins play a fundamental role in microbial physiology and are frequently virulence factors, sortase enzymes have been intensely studied since their discovery a little more than a decade ago. Based on their primary sequences and functions sortases can be partitioned into distinct families called class A to F enzymes. Most bacteria elaborate their surfaces using more than one type of sortase that function non-redundantly by recognizing unique sorting signals within their protein substrates. Here we review what is known about the functions of these enzymes and the molecular basis of catalysis. Particular emphasis is placed on 'pilin' specific class C sortases that construct structurally complex pili. Exciting new data have revealed that these enzymes are amazingly promiscuous in the substrates that they can employ and that there is a startling degree of diversity in their mechanism of action. We also review recent data that suggest that sortases are targeted to specific sites on the cell surface where they work with other sortases and accessory factors to properly function.     

Computational analysis of the fructosyltransferase enzymes in plants, fungi and bacteria

Fructosyltransferases (FTases) are enzymes produced by plants, fungi, and bacteria, which are responsible for the synthesis of fructooligosaccharides. In this study, we conducted a computational analysis of reported sequences for FTase from a diverse source of organisms, such as plants, fungi, and bacteria. Ninety-one proteins sequences were obtained; all belonging to the glycoside hydrolase 32 (GH32) and 68 (GH68) families. The sequences were grouped in seven clades, five for plants, one for fungi, and one for bacteria. Our findings suggest that FTases from fungi and bacteria likely evolved from dicotyledonous FTases. The analysis of catalytic domains A, D and E, which contain the amino acids involved in the catalytic binding site, allowed the identification of clade-specific conserved characteristics. The analysis of sequence motifs involved in donor/acceptor molecule affinity showed that additional sequences could be responsible for donor/acceptor molecule affinity. The correlation of this large set of FTases allowed to identify additional features that might be used for the identification and classification of new FTases, and to improve the understanding of these valuable enzymes.     

Starch-hydrolyzing enzymes from thermophilic archaea and bacteria

Extremophlic microorganisms have developed a variety of molecular strategies in order to survive in harsh conditions. For the utilization of natural polymeric substrates such as starch, a number of extremophiles, belonging to different taxonomic groups, produce amylolytic enzymes. This class of enzyme is important not only for the study of biocatalysis and protein stability at extreme conditions but also for the many biotechnological opportunities they offer. In this review, we report on the different molecular properties of thermostable archaeal and bacterial enzymes including alpha-amylase, alpha-glucosidase, glucoamylase, pullulanase, and cyclodextrin glycosyltransferase. Comparison of the primary sequence of the pyrococcal pullulanase with other members of the glucosyl hydrolase family revealed that significant differences are responsible for the mode of action of these enzymes.     

Encapsulation of enzymes by radiation technique

Summary A new preparative technique for the encapsulation of enzymes by radiation polymerization was studied using cellulase, 2-hydroxyethyl methacrylate, and tetraethylene-glycol diacrylate. The enzyme activity of the immobilized enzyme capsules varied with the thickness of the membrane and with the size of the capsule; optimum size and thickness giving high enzyme activity were 0.5 – 2 mm and 50 – 200 m, respectively. The durability of the capsules was examined by continmuous enzyme reaction.