Biochemical studies on the production of neuraminidase by environmental isolates of Vibrio cholerae non-O1 from Bulgaria

2011 ◽  
Vol 57 (7) ◽  
pp. 606-610 ◽  
Author(s):  
Rumyana Eneva ◽  
Stephan Engibarov ◽  
Tanya Strateva ◽  
Radoslav Abrashev ◽  
Ignat Abrashev
Keyword(s):  
Vibrio Cholerae ◽  
Pathogenic Bacteria ◽  
Environmental Isolates ◽  
Anaerobic Conditions ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Cholera Vibrio ◽  
Key Factor ◽  
Aeration Conditions ◽  
The One

Neuraminidase is a key factor in the infectious process of many viruses and pathogenic bacteria. The neuraminidase enzyme secreted by the etiological agent of cholera — Vibrio cholerae О1 — is well studied in contrast with the one produced by non-O1/non-O139 V. cholerae. Environmental non-O1/non-O139 V. cholerae isolates from Bulgaria were screened for production of neuraminidase. The presence of the neuraminidase gene nanH was detected in 18.5% of the strains. Тhe strain showing highest activity (30 U/mL), V. cholerae non-O1/13, was used to investigate the enzyme production in several media and at different aeration conditions. The highest production of extracellular neuraminidase was observed under microaerophilic conditions, which is possibly related to its role in the infection of intestine epithelium, where the oxygen content is low. On the other hand, this is another advantage of the microbe in such microaerophilic environments as sediments and lake mud. The highest production of intracellular neuraminidase was observed at anaerobic conditions. The ratio of extracellular to intracellular neuraminidase production in V. cholerae was investigated. The temperature optimum of the enzyme was determined to be 50 °C and the pH optimum to be 5.6–5.8.

The Reaction of Thiol Compounds with the Vitamin-K Dependent Clotting Factors

1969 ◽  
Vol 21 (03) ◽  
pp. 573-579 ◽  
Author(s):  
P Fantl
Keyword(s):  
Prothrombin Time ◽  
Vitamin K ◽  
Anaerobic Conditions ◽  
Clotting Factors ◽  
Thiol Compounds ◽  
Aerobic Conditions ◽  
One Stage ◽  
Factor Ii ◽  
Ph Dependent ◽  
The One

SummaryTreatment of human and dog oxalated plasma with 0.2 to 1.0 × 10−1 M 2.3-dithiopropanol (BAL) or dithiothreitol (DTT) at 2–4° C for 30 min results in the reduction of the vitamin-K dependent clotting factors II, VII, IX and X to the respective-SH derivatives. The reaction is pH dependent. Under aerobic conditions the delayed one stage prothrombin time can be partly reversed. Under anaerobic conditions a gradual prolongation of the one stage prothrombin time occurs without reversal.In very diluted plasma treated with the dithiols, prothrombin can be converted into thrombin if serum as source of active factors VII and X is added. In contrast SH factors VII, IX and X are inactive in the specific tests. Reoxidation to active factors II, VII, IX and X takes place during adsorption and elution of the SH derivatives. The experiments have indicated that not only factor II but also factors VII, IX and X have active-S-S-centres.

Biosynthesis of the Diguanosine Nucleotides. I. Purification and Properties of an Enzyme from Yolk Platelets of Brine Shrimp Embryos

1974 ◽  
Vol 52 (3) ◽  
pp. 231-240 ◽  
Author(s):  
A. H. Warner ◽  
P. C. Beers ◽  
F. L. Huang
Keyword(s):  
Molecular Weight ◽  
Brine Shrimp ◽  
Artemia Salina ◽  
Temperature Optimum ◽  
Small Molecular Weight ◽  
Ph Optimum ◽  
Optimal Activity ◽  
Purification And Properties

An enzyme that catalyzes the synthesis of P1P4-diguanosine 5′-tetraphosphate (Gp4G) has been isolated and purified from yolk platelets of encysted embryos of the brine shrimp, Artemia salina. The enzyme GTP:GTP guanylyltransferase (Gp4G synthetase) utilizes GTP as substrate, has a pH optimum of 5.9–6.0, a temperature optimum of 40–42 °C, and requires Mg2+ and dithiothreitol for optimal activity. The synthesis of Gp4G is inhibited markedly by pyrophosphate, whereas orthophosphate has no effect on the reaction. In the presence of GDP the enzyme also catalyzes the synthesis of P1,P3-diguanosine 5′-triphosphate (Gp3G), but the rate of synthesis is low compared with Gp4G synthesis and dependent upon other small molecular weight components of yolk platelets.

Temperature-induced alanine oxidation in a psychrotrophic Pseudomonas

1975 ◽  
Vol 21 (12) ◽  
pp. 2028-2033
Author(s):  
Prince K. Zachariah ◽  
John Liston
Keyword(s):  
Heat Treatment ◽  
Enzyme Synthesis ◽  
Optimum Temperature ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sephadex Column ◽  
Oxidase System ◽  
Psychrotrophic Bacteria ◽  
Induction Of Enzymes ◽  
Elution Fraction

A psychrotrophic pseudomonad isolated from iced fish oxidized alanine at temperatures close to 0 °C and grew over the range 0 °C–35 °C. The rate of oxidation of alanine, measured manometrically, by cells grown at 2 °C was lower than that of cells grown at 22 °C. However, the consumption of oxygen after heat treatment at 35 °C for 35 min was reduced considerably by 2 °C grown cells. Alanine oxidase activity was tested in an extract from cells grown at 2 °C and 22 °C with alanine as the sole carbon, nitrogen, and energy source. Cells grown at 2 °C produced an alanine oxidase with a temperature optimum of 35 °C and pH optimum of 8, which lost about 80% activity by heat treatment at 40 °C for 30 min. There was no change in activity after dialysis at pH 7, 8, or 9. Extracts from cells grown at 22 °C contained an alanine oxidase system with an optimum temperature of 45 °C, a pH optimum above 8, and only about 30% reduction of activity after heat treatment. This enzyme activity was concentrated in the 0.5 M elution fraction from a Sephadex column, and dialysis reduced the activity at pH 7 and 8. Mesophilic enzyme synthesis apparently started around a growth temperature of 10 °C.The crude alanine oxidase systems of Pseudomonas aeruginosa derived from cells grown at 13 °C and 37 °C had a common optimum temperature of 45 °C. These data suggest that one mechanism of psychrophilic growth by psychrotrophic bacteria may be the induction of enzymes with low optimum temperatures in response to low temperature conditions.

Cellulase production by Acetivibrio cellulolyticus

1980 ◽  
Vol 26 (7) ◽  
pp. 760-765 ◽  
Author(s):  
J. N. Saddler ◽  
A. W. Khan
Keyword(s):  
Sewage Sludge ◽  
Cellulose Degradation ◽  
Cellulase Production ◽  
Cellulolytic Enzymes ◽  
Exponential Growth Phase ◽  
Cellulose Powder ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Culture Supernate ◽  
Cellulose Concentration

Acetivibrio cellulolyticus, an isolate from an established sewage sludge culture, degraded cellulose powder, Avicel cellulose, and cellobiose. The organism showed maximum cellulose degradation in a medium containing 10 g/L of cellulose and it could also degrade cellulose in media containing up to 75 g/L of cellulose. During the exponential growth phase, large quantities of cellulolytic enzymes were found extracellularly whereas cellobiase activity was cell associated. The crude culture supernate contained endo- and exo-glucanase activities with a pH optimum at 5.0 and a temperature optimum at 50 °C. Maximum cellulase activities were detected in 2- to 3-day-old cultures grown on 1 g/L of cellulose. Cellulose concentration above 10 g/L caused the adsorption of these enzymes to the substrate and consequently lowered their detection in the supernate. The activities at 50 °C for endoglucanase, exoglucanase, and filter paper degrading ability, expressed as micrograms of glucose equivalents released per minute per milligram of protein culture supernate, were 510, 135, and 40 respectively.

STUDIES ON SOLUBILIZED ADENYLATE KINASE FROM MITOCHONDRIA

1966 ◽  
Vol 44 (11) ◽  
pp. 1469-1475 ◽  
Author(s):  
Marjorie A. Brewster ◽  
Ezzat S. Younathan
Keyword(s):  
Activation Energy ◽  
Rat Liver ◽  
Adenylate Kinase ◽  
Divalent Cations ◽  
Metabolic Function ◽  
Kcal Mole ◽  
Temperature Optimum ◽  
Ph Optimum ◽  
Sensitive Method

Adenylate kinase from mitochondria of rat liver was made soluble by sonication. The enzyme had a pH optimum of 8.0, temperature optimum of 30°, and activation energy of 12.2 kcal/mole. It was activated by several divalent cations in the following order of efficiency: Mg++ > Co++ > Mn++ > Ca++, with an optimal Mg++: ADP ratio of 1. The apparent Km value (ADP as substrate) was found to be 1.3 mM at pH 7.4 and 30°. The activity was sensitive to phloretin and mildly activated by aurovertin. Oligomycin, 2,4-dinitrophenol, p-chloromercuribenzoate, alloxan, and phlorizin had no effect on the activity. The metabolic function and a comparison of the properties of this solubilized mitochondrial adenylate kinase with those of similar preparations from other sources are discussed in the light of these findings. During this study, a sensitive method adaptable for a large number of assays of adenylate kinase was developed, and is described in detail.

scholarly journals MLVA-TYPING OF CLINICAL STAMPS OF GENETICALLY CHANGED VIBRIO CHOLERAE BIOTYPE EL TOR INSULATED IN RUSSIA AND UKRAINE IN THE PERIOD OF SEVENTH PANDEMIC CHOLERA

2018 ◽  
pp. 37-43
Author(s):  
I. V. Savelieva ◽  
A. N. Kulichenko ◽  
V. N. Saveliev ◽  
D. A. Kovalev ◽  
O. V. Vasilieva ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Vibrio Cholerae ◽  
Genetically Modified ◽  
Cholera Vibrio ◽  
Separate Branch ◽  
Comparative Aspect ◽  
The Russian Federation ◽  
Time Periods ◽  
El Tor ◽  
Mlva Typing

Aim. Conduct in a comparative aspect MLVA-typing of genetically altered cholera vibrio biovar El Tor, isolated from patients during the epidemic (1994) and outbreaks (1993, 1998) in Dagestan with isolates in Mariupol (Ukraine) in 1994-2011 in Moscow (2010, 2012), India (1964, 2006, 2007), Bangladesh 1991, 1994, 2001, 2004) and to establish Phylogenetic connections between strains of cholera vibrios isolated in different years in these territories, to ascertain the source of their drift. Materials and methods. MLVA-tyP-ing was carried out in PCR at 5 variable loci of 35 clinical strains of genetically modified Vibrio cholerae byotyPe El Tor. The obtained amPlicon was studied in the system of automatic caPillary electroPhoresis ExPerion («Bio Rad Laboratories», USA). For Phylogenetic analysis, along with MLVA-genotyPes, 35 strains of Vibrio cholerae from the Institute's collection used Published genotyPes of strains isolated in India, Bangladesh, Haiti. Results. The investigated strains of cholera vibrio are referred to 21 MLVA-tyPes, divided into 2 main clades and 1 seParate branch with clonal clusters and subclusters, each of which contains closely related strains of cholera vibrio genovariants having a different degree of Phylogenetic relationshiP - full or Partial identity of allelic Profiles of five variable loci. The sources of drift of genetically modified Vibrio cholerae byotyPe El Tor to Russia and Ukraine from disadvantaged cholera of India, Bangladesh, Azerbaijan and the countries of the Middle East have been established. Conclusion. The obtained data testify to the PolymorPhism of MLVA-tyPes of genetically altered strains of cholera vibrio of the biologist El Tor, evolved in different years and caused ePidemics or outbreaks of cholera in different territories during different time Periods of the course of the seventh cholera Pandemic, and also suggest the Polyclonal origin of the Vibrio cholerae biovar El Tor and the source of their drift to the territory of the Russian Federation and Ukraine.

scholarly journals Fresh extension of Vibrio cholerae competence type IV pili predisposes them for motor-independent retraction

2021 ◽  
Author(s):  
Jennifer L. Chlebek ◽  
Triana N. Dalia ◽  
Nicolas Biais ◽  
Ankur B. Dalia
Keyword(s):  
Cell Surface ◽  
Vibrio Cholerae ◽  
Conformational Changes ◽  
Pathogenic Bacteria ◽  
Ectopic Expression ◽  
Type Iv Pili ◽  
Therapeutic Interventions ◽  
Dynamic Activity ◽  
Type Iv ◽  
Additional Support

ABSTRACTBacteria utilize dynamic appendages called type IV pili (T4P) to interact with their environment and mediate a wide variety of functions. Pilus extension is mediated by an extension ATPase motor, commonly called PilB, in all T4P. Pilus retraction, however, can either occur with the aid of an ATPase motor, or in the absence of a retraction motor. While much effort has been devoted to studying motor-dependent retraction, the mechanism and regulation of motor-independent retraction remains poorly characterized. We have previously demonstrated that Vibrio cholerae competence T4P undergo motor-independent retraction in the absence of the dedicated retraction ATPases PilT and PilU. Here, we utilize this model system to characterize the factors that influence motor-independent retraction. We find that freshly extended pili frequently undergo motor-independent retraction, but if these pili fail to retract immediately, they remain statically extended on the cell surface. Importantly, we show that these static pili can still undergo motor-dependent retraction via tightly regulated ectopic expression of PilT, suggesting that these T4P are not broken, but simply cannot undergo motor-independent retraction. Through additional genetic and biophysical characterization of pili, we suggest that pilus filaments undergo conformational changes during dynamic extension and retraction. We propose that only some conformations, like those adopted by freshly extended pili, are capable of undergoing motor-independent retraction. Together, these data highlight the versatile mechanisms that regulate T4P dynamic activity and provide additional support for the long-standing hypothesis that motor-independent retraction occurs via spontaneous depolymerization.SIGNIFICANCEExtracellular pilus fibers are critical to the virulence and persistence of many pathogenic bacteria. A crucial function for most pili is the dynamic ability to extend and retract from the cell surface. Inhibiting this dynamic pilus activity represents an attractive approach for therapeutic interventions, however, a detailed mechanistic understanding of this process is currently lacking. Here, we use the competence pilus of Vibrio cholerae to study how pili retract in the absence of dedicated retraction motors. Our results reveal a novel regulatory mechanism of pilus retraction that is an inherent property of the external pilus filament. Thus, understanding the conformational changes that pili adopt under different conditions may be critical for the development of novel therapeutics that aim to target the dynamic activity of these structures.

scholarly journals CBX7 is Dualistic in Cancer Progression Based on its Function and Molecular Interactions

2021 ◽  
Vol 12 ◽  
Author(s):  
Jun Li ◽  
Taohui Ouyang ◽  
Meihua Li ◽  
Tao Hong ◽  
MHS Alriashy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cancer Progression ◽  
Circular Rnas ◽  
Regulate Gene Expression ◽  
Epigenetic Regulator ◽  
Key Factor ◽  
The One ◽  
Related Proteins ◽  
Polycomb Repressive Complex 1 ◽  
Oncosuppressor Genes

Chromobox protein homolog 7 (CBX7) is a member of the Chromobox protein family and participates in the formation of the polycomb repressive complex 1(PRC1). In cells, CBX7 often acts as an epigenetic regulator to regulate gene expression. However, pathologically, abnormal expression of CBX7 can lead to an imbalance of gene expression, which is closely related to the occurrence and progression of cancers. In cancers, CBX7 plays a dual role; On the one hand, it contributes to cancer progression in some cancers by inhibiting oncosuppressor genes. On the other hand, it suppresses cancer progression by interacting with different molecules to regulate the synthesis of cell cycle-related proteins. In addition, CBX7 protein may interact with different RNAs (microRNAs, long noncoding RNAs, circular RNAs) in different cancer environments to participate in a variety of pathways, affecting the development of cancers. Furthermore, CBX7 is involved in cancer-related immune response and DNA repair. In conclusion, CBX7 expression is a key factor in the occurrence and progression of cancers.

What Italian business disliked about a European common market

2008 ◽  
Vol 49 (2) ◽  
Author(s):  
Francesca Fauri
Keyword(s):  
Great Majority ◽  
Production Costs ◽  
Export Market ◽  
Export Demand ◽  
Italian Economy ◽  
Key Factor ◽  
Treaty Of Rome ◽  
The One ◽  
Medium Firms ◽  
Opening Up

AbstractThe possibility of enlarging Italy’s export market was the key factor that made industrialists repeatedly express their consent for a unified market, even in their earliest statements on the matter. The great majority of Italian business declared itself in favour of a united market dependent upon a given set of conditions: gradual abolition of tariffs, leveling of production costs among members, free circulation of workers (as well as of goods and capital) and inclusion in the Treaty of Art.109 on the resumption of tariff controls or measures of safeguard where a sudden crisis in the balance of payments occurs.The policy of Italian business towards EEC integration in those years was the result of a compromise between protectionist sectors (small-medium firms) on the one hand and, on the other, firms belonging to the so-called automobile cycle (Fiat, Pirelli etc.) and the engineering sector, whose growth had been led by export demand and favoured opening up the Italian economy to international competition.Once the Treaty of Rome was signed, there were issues that Italian industrialists did not like. However, on the whole, participation was never called into question and, despite a few skeptical voices, Italian business valued European integration as a unique opportunity to enlarge the market, increase foreign demand and improve competitiveness. The Italian economic miracle had begun to take shape.

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