Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lactic acid bacteria (LAB) comprise a diverse group of Gram-positive, non-spore-forming microorganisms. These bacteria are widely used in food technology. The species identification of LAB depends mainly on physiological and biochemical criteria. The esterolytic systems of LAB remain poorly characterized. Esterases (EC 3.1.1.3) represent a diverse group of hydrolases catalyzing the cleavage and formation of esters bonds Screening of esterases is usually performed either by employing chromophoric substances (e.g., alpha- or beta-naphthyl esters of short-chain fatty acids). The post-electrophoretic detection of esterases is a sensitive technique applied in bacterial systems, that mainly provides information on the similarity of strains within the same species or subspecies according to their esterase patterns. This technique is principally used to determine the number and substrate specificity of esterases and lipases, revealing the complexity of lipase and esterase systems. The present chapter describes the technique of polyacrylamide gel electrophoresis (PAGE; in the absence of sodium dodecyl sulfate [SDS]), in non-denaturing conditions, to find intracellular fractions for strain typing of LAB.
Methods Mol Biol 2004
PMID:Differentiation of lactic acid bacteria strains by postelectrophoretic detection of esterases. 1515 58

Lactic acid bacteria (LAB) are considered weakly lipolytic compared with many other groups of bacteria (e.g., Pseudomonas, Bacillus, and Achromobacter). The esterolytic and lipolytic systems of dairy LAB remain poorly characterized. Esterases from lactic acid bacteria, yeasts, and Pseudomonas organisms may be involved in the development of fruity flavors in foods, and pregastric lipase and esterases are essential for the development of typical flavor in Italian cheese. Microbial lipases and esterases may improve quality or accelerate the maturation of cheeses, cured bacon, and fermented sausages. Lipases are defined as glycerol ester hydrolases (EC 3.1.1.3) that hydrolyze tri-, di-, and monoglycerides present at an oil-water interface. Esterases (EC 3.1.1.6) hydrolyze esters in solution and may also hydrolyze tri- and especially di- and monoglycerides containing short-chain fatty acids. Some probiotic strains of LAB can hydrolyze the triglycerides, releasing most short and medium chain, and essential fatty acids, which are valuable to today's health-conscious consumer. Medium chain fatty acids (C6-C14), in particular, have become accepted treatment for patients with malabsorption symptoms, a variety of metabolic disorders, cholesterol problems, and infant malnutrition. These probiotic bacteria could alleviate lipase deficiency in the digestive tract during digestion (steatorrhea). In this chapter, we describe different methods routinely used in our laboratory to determine the esterolytic and lipolytic activity of LAB. These techniques include the use of alpha- and beta-naphthyl derivatives of fatty acids (chromogenic method), the p-nitrophenyl (pNP) derivative of fatty acids (chromogenic method), and triglycerides (agar-well assay technique and titrimetric test) as substrates.
Methods Mol Biol 2004
PMID:Determination of esterolytic and lipolytic activities of lactic acid bacteria. 1515 59

Many technological parameters that affect the nature and functional properties of proteins are involved in the preparation of meat products. The dry-curing process is quite complex because of the coexistence of enzymes from endogenous and bacterial origins. The protein breakdown that takes place during the ripening of dry fermented sausages leads to an increase in the concentration of peptides and free amino acids. The proteolytic events have been thoroughly investigated not only because of their physiological significance but also for their technological connotations in terms of texture and flavor development. Lactic acid bacteria and Staphylococcus or Kocuria are used as starter cultures in fermented meat products. In recent years, the proteolytic system of lactobacilli involved in meat fermentation became the focus of an increasing number of studies because of the technological roles of these organisms. Although results obtained from broth systems show proteolytic activity, studies involving food systems must be done to confirm their effectiveness. A simplified soluble muscle extract to determine the capacity to degrade meat proteins by lactic acid bacteria was developed using a spectrophotometric method based on the reaction of the alpha-amino groups released by hydrolysis with o-phtaldialdehyde and beta-mercaptoethanol to form an adduct (1-thioalkyl-2-alkylisoindoles) that is enhanced at basic pH and absorbs strongly at 360 nm.
Methods Mol Biol 2004
PMID:Meat-model system development for proteolytic activity determination. 1515 60

The physiological responses to exercise and stress of the Antarctic labriform swimmer Pagothenia borchgrevinki were compared to the temperate labriform swimmers Notolabrus celidotus and Notolabrus fucicola. Basic swimming characteristics were very similar amongst the three species with P. borchgrevinki showing a reduced capacity for exercise. P. borchgrevinki showed large increases in haematocrit (Hct) following exercise that were not seen in the temperate species. Lactate dehydrogenase (LDH) activities were high in the white myotomal muscle from the Antarctic fish, with a distinct indication of metabolic cold adaptation in this enzyme. Nevertheless, although the temperate fish showed elevated muscle lactate concentrations following either exercise or electrical stimulation the Antarctic fish did not. The data suggest that poor anaerobic performance of white muscle is associated with the labriform mode of locomotion.
Comp Biochem Physiol A Mol Integr Physiol 2004 Jul
PMID:Mode of locomotion places selective pressures on Antarctic and temperate labriform swimming fish. 1531 95

Fructose is a major dietary sugar, which is elevated in the serum of diabetic humans, and is associated with metabolic syndromes important in the pathogenesis of diabetic complications. The facilitative fructose transporter, GLUT5, is expressed in insulin-sensitive tissues (skeletal muscle and adipocytes) of humans and rodents, where it mediates the uptake of substantial quantities of dietary fructose, but little is known about its regulation. We found that GLUT5 abundance and activity were compromised severely during obesity and insulin resistance in Zucker rat adipocytes. Adipocytes from young obese (fa/fa), highly insulin-responsive Zucker rats contained considerably more plasma membrane GLUT5 than those from their lean counterparts (1.8-fold per microgram membrane protein), and consequently exhibited higher fructose transport (fivefold) and metabolism (threefold) rates. Lactate production was the preferred route for fructose metabolism in these cells. As the rats aged and become more obese and insulin-resistant, adipocyte GLUT5 surface density (12-fold) and fructose transport (10-fold) and utilisation rates (threefold) fell markedly. The GLUT5 loss was more dramatic in adipocytes from obese animals, which developed a more marked insulin resistance than lean counterparts. The decline of GLUT5 levels in adipocytes from older, obese animals was not a generalised effect, and was not observed in kidney, nor was this expression pattern shared by the alpha1 subunit of the Na+/K+ ATPase. Our findings suggest that plasma membrane GLUT5 levels and thus fructose utilisation rates in adipocytes are dependent upon cellular insulin sensitivity, inferring a possible role for GLUT5 in the elevated circulating fructose observed during diabetes, and associated pathological complications.
Mol Cell Biochem 2004 Jun
PMID:Fructose transport and metabolism in adipose tissue of Zucker rats: diminished GLUT5 activity during obesity and insulin resistance. 1536 82

Lactate and succinate were produced from glucose by Corynebacterium glutamicum under oxygen deprivation conditions without growth. Addition of bicarbonate to the reaction mixture led not only to a 3.6-fold increase in succinate production rate, but also to a 2.3- and 2.5-fold increase, respectively, of the rates of lactate production and glucose consumption, compared to the control. Furthermore, when small amounts of pyruvate were added to the reaction mixture, acid production rates and the glucose consumption rate were multiplied by a factor ranging from 2 to 3. These phenomena were paralleled by an increase in the NAD(+)/NADH ratio, thus corroborating the view that the efficient regeneration of NAD(+) could be triggered by the addition of either bicarbonate or pyruvate. To investigate the global metabolism of corynebacteria under oxygen deprivation conditions, we engineered several strains where the genes coding for key metabolic enzymes had been inactivated by gene disruption and replacement. A lactate dehydrogenase (LDH)-deficient mutant was not able to produce lactate, suggesting this enzyme has no other isozyme. Although a pyruvate carboxylase (pyc) mutant exhibited similar behavior to that of the wild type, phosphoenolpyruvate carboxylase (ppc) mutants were characterized by a dramatic decrease in succinate production, which was concomitant to decreased lactate production and glucose consumption rates. This set of observations corroborates the view that in coryneform bacteria under oxygen deprivation conditions the major anaplerotic reaction is driven by the ppc gene product rather than by the pyc gene product. Moreover, intracellular NADH concentrations in C. glutamicum were observed to correlate to oxygen-deprived metabolic flows.
J Mol Microbiol Biotechnol 2004
PMID:Metabolic analysis of Corynebacterium glutamicum during lactate and succinate productions under oxygen deprivation conditions. 1538 16

Stem cells have been shown to partly restore central nervous system (CNS) function after transplantation into the injured CNS. However, little is known about their influence on acute energy metabolism after spinal cord injury. The present study was designed to analyze regional changes in energy metabolites. Young adult mice were subjected to laminectomy with subsequent hemisection at the L2/3 vertebral level. Immediately thereafter a stable clone of murine neural stem cells (NSCs) was injected into the lesion site. After 4 and 24 h, spinal cords were removed and ATP, glucose, and lactate were analyzed by a bioluminescence approach in serial sections and compared to a laminectomized (intact control), hemisected-only or hemisected vehicle-injected control group. At both time points, ATP content of the hemisected group in the tissue segments adjacent to the lesion was increased when compared to the laminectomized control. At the lesion site ATP content decreased significantly at 24 h in the cell-transplanted group when compared to the laminectomized control group. Glucose content decreased at the lesion site and in segments adjacent to the lesion at both time points and in all experimental groups when compared to the laminectomized control group. Lactate content decreased significantly at 4 h in the caudal segments of the vehicle-injected group and in both adjacent segments of the transplanted group when compared to the laminectomized control. At the lesion site, lactate content decreased significantly at 4 and 24 h in the cell-transplanted group, when compared to the laminectomized control. The area of ATP decline at the lesion site 24 h postinjury was significantly lower in the vehicle control group as compared to the hemisected or transplanted group. The decrease in glucose combined with an increase in ATP in the lesion-adjacent segments may indicate that the tissue responds with an increased use of glucose to support itself with sufficient ATP. The significant decrease in glucose, lactate, and ATP in the cell-transplanted group at 24 h may indicate a high metabolic need of the stem cells. The lower area of ATP decline 24 h after vehicle administration suggests that the vehicle solution washes out toxic mediators, thus ameliorating hemisection-dependent secondary tissue damage.
J Mol Neurosci 2004
PMID:Regional energy metabolism following short-term neural stem cell transplantation into the injured spinal cord. 1545 36

Overactivation of poly(ADP-ribose) polymerase-1 (PARP-1) in response to oxidative stress has been shown to contribute to necrotic cell death by consuming NAD+ and ATP. In the present study, PARP-1 overactivation was determined by identifying the distribution and accumulation of poly(ADP-ribose) following intraperitoneal administration of a hepatotoxic dose of carbon tetrachloride (572 mg/kg). Treated animals exhibited lipid peroxide levels 16.5-fold higher than controls. Serum activities of glutamic pyruvic transaminase and glutamic oxaloacetic transaminase were increased by 6.1-fold and 22.8-fold, respectively. Lactate dehydrogenase activity was significantly increased by 1.2-fold. Histopathological analyses revealed severe necrosis and increased poly(ADP-ribsyl)ation of cells in the centrilobular region of treated animals versus saline controls. These results demonstrate the role of PARP-1 overactivation in chemical-induced pathologies and suggest the potential role of PARP-1 inhibitors at preventing toxicity.
Res Commun Mol Pathol Pharmacol 2003
PMID:Hepatocellular accumulation of poly(ADP-ribose) in male ICR mice treated with a necrogenic dose of carbon tetrachloride. 1568 16

Aging is associated with reduced tolerance to ischemic insult, and genesis of this intolerant phenotype is poorly understood. We characterized effects of aging and gender on cardiovascular function and cell damage during 20 min ischemia and 60 min reperfusion in isolated hearts from young adult (2-4 months), mature adult (8 months), middle-aged (12 months), aged (18 months), and senescent (24-28 months) C57/Bl6 mice. Aging substantially impaired recovery of ventricular contractility, with this change primarily evident within 12 months of age. In males ventricular developed pressure recovered to 72 +/- 8 mmHg in young hearts vs. only 44 +/- 7, 30 +/- 3, 24 +/- 5, and 27 +/- 4 mmHg in mature, middle-aged, aged and senescent hearts, respectively. This pattern was largely due to worsened diastolic dysfunction. Coronary flow recovered to below pre-ischemic levels in all ages, correlating with contractile recovery. However, coronary dysfunction (impaired responses to 2-chloroadenosine and ADP) was unaltered by senescence. Lactate dehydrogenase (LDH) loss, a marker for oncosis, increased to middle-age (approximately twofold), then fell with further aging to a value no longer different from that in young adult hearts. Similar patterns of change were observed in female hearts, although LDH efflux was significantly lower in mature adult and middle-aged female vs. male hearts, with functional tolerance also tending to be greater at these ages (though not achieving significance). Overall, our data reveal age-related ischemic intolerance develops well before senescence, being primarily evident by "middle-age". Phenotypic changes appear selective for myocardial vs. vascular injury, and functional vs. oncotic injury. Similar changes occur in males and females, though there is evidence of a protected phenotype in mature to middle-aged female vs. male hearts.
J Mol Cell Cardiol 2005 Feb
PMID:Age-related changes in ischemic tolerance in male and female mouse hearts. 1569 30

A lactate permease was biochemically identified in Candida albicans RM1000 presenting the following kinetic parameters at pH 5.0: Km 0.33+/-0.09 mM and Vmax 0.85+/-0.06 nmol s(-1) mg dry wt(-1). Lactate uptake was competitively inhibited by pyruvic and propionic acids; acetic acid behaved as a non-competitive substrate. An open reading frame (ORF) homologous to Saccharomyces cerevisiae gene JEN1 was identified (CaJEN1). Deletions of both CaJEN1 alleles of C. albicans (resulting strain CPK2) resulted in the loss of all measurable lactate permease activity. No CaJEN1 mRNA was detectable in glucose-grown cells neither activity for the lactate transporter. In a medium containing lactic acid, CaJEN1 mRNA was detected in the RM1000 strain, and no expression was found in cells of CPK2 strain. In a strain deleted in the CaCAT8 genes the expression of CaJEN1 was significantly reduced, suggesting the role of this gene as an activator for CaJEN1 expression. Both in C. albicans and in S. cerevisiae cells CaJEN1-GFP fusion was expressed and targeted to the plasma membrane. The native CaJEN1 was not functional in a S. cerevisiae jen1delta strain. Changing ser217-CTG codon (encoding leucine in S. cerevisiae) to a TCC codon restored the permease activity in S. cerevisiae, proving that the CaJEN1 gene codes for a monocarboxylate transporter.
Mol Membr Biol
PMID:The disruption of JEN1 from Candida albicans impairs the transport of lactate. 1576 70


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>