Enterocin HZ produced by a wildEnterococcus faeciumstrain isolated from a traditional, starter-free pickled cheese

2014 ◽  
Vol 81 (2) ◽  
pp. 164-172 ◽  
Author(s):  
Zeliha Yildirim ◽  
Harun Bilgin ◽  
Hilal Isleroglu ◽  
Kader Tokatli ◽  
Didem Sahingil ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Maximum Level ◽  
Biologically Active ◽  
Logarithmic Phase ◽  
16S Rrna Analysis ◽  
Uht Milk ◽  
Late Logarithmic Phase ◽  
Initial Ph ◽  
90 C 30 ◽  
C 30

BacteriogenicEnterococcus faeciumHZ was identified by using biochemical (Strep-API 20, API-50 CHL, fatty acid profile) and 16S rRNA analysis (99·99 %).Ent. faeciumHZ was sensitive to clinically important antibiotics such as vancomycin, and did not have gelatinase and haemolysis activities. Enterocin HZ, a bacteriocin fromEnt. faeciumHZ, was sensitive to papain and tyripsin, but resistant to pepsin, lipase, catalase, α-amylase, organic solvents, detergents, ß-mercaptoethanol, and heat treatment (90 °C/30 min). It was biologically active at pH 2·0–9·0 and synthesised at the highest level in MRS or M17 broth at 32 or 37 °C with an inoculum amount of 0·1–0·5 % and an initial pH of 6·0–7·0. Enterocin HZ production reached maximum level at middle and late logarithmic phase and its molecular weight was ∼4·5 kDa. It was active against some Gram-positive foodborne bacteria.Ent. faeciumHZ or its bacteriocin enterocin HZ is a good candidate to be studied as a food biopreservative since enterocin HZ showed strong bactericidal activity againstListeria monocytogenesin UHT milk and alsoEnt. faeciumHZ grew very well in milk and produced enterocin HZ at maximum level.

Demonstration of opsonizing antibodies to Francisella tularensis by leukocyte chemiluminescence

1980 ◽  
Vol 29 (2) ◽  
pp. 329-334
Author(s):  
S Löfgren ◽  
A Tärnvik ◽  
J Carlsson
Keyword(s):  
Heat Treatment ◽  
Francisella Tularensis ◽  
Immunoglobulin G ◽  
Immune Serum ◽  
Agglutination Reaction ◽  
Time Intervals ◽  
Reaction Heat ◽  
Complement Component C3 ◽  
Pmn Leukocytes ◽  
C 30

Twenty-three individuals were vaccinated with a viable attenuated strain of Francisella tularensis, and blood was collected at various time intervals during 4 weeks. To demonstrate opsonizing antibodies, a mixture of serum and vaccine bacteria was incubated, whereafter the chemiluminescence response of polymorphonuclear (PMN) leukocytes to this mixture was recorded. No opsonizing antibodies against F. tularensis were found in sera obtained before vaccination. Eleven days after vaccination, sera from nine individuals, and 21 days after vaccination, sera from all 23 individuals contained antibodies. Antibodies were demonstrated earlier with the chemiluminescent technique that with the agglutination reaction. Heat treatment (56 degrees C, 30 min) or removal of complement component C3 from immune serum reduced the chemiluminescent response of the leukocytes. A high chemiluminescent response of the leukocytes was induced by immunoglobulin G (IgG)- and IgM-enriched fractions of immune serum in the presence of complement. In the absence of complement, the IgG fraction induced a low chemiluminescent response; the IgM fraction induced no response at all.

Adsorption of Chromium (VI) from Aqueous Solution by Agricultural Waste Derived Activated Carbon

2013 ◽  
Vol 726-731 ◽  
pp. 2100-2106 ◽  
Author(s):  
Hua Zhang ◽  
Xue Hong Zhang ◽  
Yi Nian Zhu ◽  
Shou Rui Yuan
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Agricultural Waste ◽  
Order Kinetic ◽  
Chromium Vi ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Grapefruit Peel ◽  
Pseudo Second Order ◽  
C 30

Activated carbon prepared from grapefruit peel, an agricultural solid waste by-product, has been used for the adsorption of Cr(VI) from aqueous solution. The effects of adsorbent dosage, pH and temperature on adsorption of Cr(VI) were investigated. The maximum adsorption yield was obtained at the initial pH of 3. The dynamical data fit very well with the pseudo-second-order kinetic model and the calculated adsorption capacities (23.98, 24.33 and 24.81 mg/g) were in good agreement with experiment results at 20°C, 30°C and 40 °C for the 100 mg/L Cr(VI) solution. The Freundlich model (R2 values were 0.9198-0.9871) fitted adsorption data better than the Langmuir model. The calculated parameters confirmed the favorable adsorption of Cr(VI) on the activated carbon prepared from grapefruit peel.

scholarly journals Ammonium removal by a novel heterotrophic nitrifying and aerobic denitrifying bacterium Pseudomonas stutzeri KTB from wastewater

2015 ◽  
Vol 50 (3) ◽  
pp. 219-227 ◽  
Author(s):  
Maohong Zhou ◽  
Hairen Ye ◽  
Xiaowei Zhao
Keyword(s):  
Nitrogen Removal ◽  
Removal Rate ◽  
Pseudomonas Stutzeri ◽  
Culture Conditions ◽  
Aerobic Denitrification ◽  
Ammonium Concentration ◽  
Logarithmic Phase ◽  
Ammonium Removal ◽  
Removal Ratio ◽  
Initial Ph

The effects of culture conditions on a newly isolated Pseudomonas stutzeri KTB's ability to simultaneously perform heterotrophic nitrification and aerobic denitrification were investigated to determine its potential of application in nitrogen removal from wastewater. The results from experiments in the presence of 10 mmol/L of ammonium were as follows: succinate was the preferred carbon source, and the optimum C/N ratio, temperature, and initial pH were 10, 30 °C, and 7–8, respectively. Nitrogen removal took place not only in the logarithmic phase but also in the stationary phase. Under the optimum conditions, the nitrogen removal rate increased as the ammonium concentration elevated, until it was as high as 60 mmol/L. Meanwhile, the maximum specific growth rate decreased. The highest nitrogen removal rate of 0.977 mmol/L/h was observed at 60 mmol/L of ammonium and the maximum removal ratio of 85.6% at 40 mmol/L when the bacterial treatment for 48 h was completed. The strain was vulnerable to even higher ammonium loads. When incubated in anaerobically digested hennery wastewater containing 43.85 mmol/L of ammonium and 2.32 mmol/L of nitrate, the removal ratio and rate reached 82.4% and 0.397 mmol/L/h, respectively. The strain might be a great candidate for ammonium removal from wastewater.

BACKGROUND CONTENT OF TECHNOGENIC AND NATURAL RADIONUCLIDES IN DETOXIFYING AND BIOLOGICALLY ACTIVE SUBSTANCES

2021 ◽  
Vol 1 (2) ◽  
pp. 223-229
Author(s):  
G.А. Zhorov ◽  
◽  
L.L. Zakharova ◽  
V.N. Obryvin ◽  
◽  
...  
Keyword(s):  
Specific Activity ◽  
Raw Materials ◽  
Natural Radionuclides ◽  
Animal Husbandry ◽  
Maximum Level ◽  
Feed Additives ◽  
Biologically Active Substances ◽  
Biologically Active ◽  
Radioactive Isotopes ◽  
Active Substances

For correctly assess the effectiveness and safety of the use of sorption-detoxifying agents and feed additives intended for animals receiving feed with an excess content of toxicants, it is necessary to take into account the background levels of radionuclides, toxic elements, pesticides and other technogenic and natural pollutants in the studied substances. The need for such studies is due both to the existence of areas with a naturally elevated level of natural toxicants in the sources of raw materials for the production of additives and drugs, and to the increasing anthropogenic influence, accompanied by the entry of xenobiotics into environmental objects. In series of radiometric studies, the specific activity of technogenic and natural radioactive isotopes (90Sr, 137Cs, 40К, 226Ra, 232Th) in a number of sorption-detoxifying and biologically active substances and preparations used in animal husbandry and veterinary medicine as part of feed additives and pharmacological agents was determined. It was found that in 43% of the studied samples, the level of specific activity of 1,1Sr in 3-90 times higher than allowed by the current standards. The maximum level of 90Sr, equal to (137±9) Bq/kg, was detected in perlite. The specific activity of 137Cs did not exceed the permissible level: in mineral sorbents its amount reached (40±7) Bq/kg, in organic and complex sorbents – (24±4), and in feed additives – (29±8) Bq/kg. The maximum levels of 40K were (1429±83) Bq/ kg in minerals (radionite) and (2613±100) Bq/kg in organic substances (lignohumate). The levels of 226Ra and 232Th did not exceed (153±13) and (79±13) Bq/kg, respectively, and were higher in the mineral samples.

The influence of milk composition on pH and calcium activity measured in situ during heat treatment of reconstituted skim milk

2010 ◽  
Vol 77 (3) ◽  
pp. 257-264 ◽  
Author(s):  
Jayani Chandrapala ◽  
Ian McKinnon ◽  
Mary Ann Augustin ◽  
Punsandani Udabage
Keyword(s):  
Heat Treatment ◽  
High Temperatures ◽  
Skim Milk ◽  
Milk Composition ◽  
Complexing Agents ◽  
Calcium Activity ◽  
Initial Ph ◽  
Ph Decrease ◽  
Milk Solids

The pH and calcium activity of reconstituted skim milk solutions (9–21% w/w milk solids non-fat) on heating and after cooling were studied as a function of milk pH prior to heating (pH 6·2–7·2 at 25°C) and added calcium complexing agents (phosphate or EDTA). The pH decreased as the temperature was raised from 25 to 90°C and the magnitude of the pH decrease was greater with increase in initial pH at 25°C before heating or milk concentration. The pH decrease on heating from 25 to 90°C in skim milk solutions with added calcium complexing agents was lower than that of milk without the addition of these salts. The calcium activity decreased on heating from 25 to 60°C. The magnitude of the change decreased with increase in initial pH at 25°C before heating and milk concentration. The decrease in calcium activity on heating from 25 to 60°C for skim milk solutions with added calcium complexing agents was lower than that of milk solutions without the addition of calcium complexing agents. The changes in pH and calcium activity on heating milk were largely reversible after cooling the milk. The results suggested that the pH and calcium activity at high temperatures are a function of the milk composition. Knowledge of the initial pH prior to heating alone is not sufficient for predicting the changes that occur during heating.

scholarly journals Expression of a Mitochondrial Peroxiredoxin Prevents Programmed Cell Death in Leishmania donovani

2006 ◽  
Vol 5 (5) ◽  
pp. 861-870 ◽  
Author(s):  
Simone Harder ◽  
Meike Bente ◽  
Kerstin Isermann ◽  
Iris Bruchhaus
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Mitochondrial Membrane ◽  
Leishmania Donovani ◽  
Physiological Role ◽  
Logarithmic Phase ◽  
Insect Vector ◽  
Oxygen Species ◽  
Late Logarithmic Phase

ABSTRACT Leishmania promastigote cells transmitted by the insect vector get phagocytosed by macrophages and convert into the amastigote form. During development and transformation, the parasites are exposed to various concentrations of reactive oxygen species, which can induce programmed cell death (PCD). We show that a mitochondrial peroxiredoxin (LdmPrx) protects Leishmania donovani from PCD. Whereas this peroxiredoxin is restricted to the kinetoplast area in promastigotes, it covers the entire mitochondrion in amastigotes, accompanied by dramatically increased expression. A similar change in the expression pattern was observed during the growth of Leishmania from the early to the late logarithmic phase. Recombinant LdmPrx shows typical peroxiredoxin-like enzyme activity. It is able to detoxify organic and inorganic peroxides and prevents DNA from hydroxyl radical-induced damage. Most notably, Leishmania parasites overexpressing this peroxiredoxin are protected from hydrogen peroxide-induced PCD. This protection is also seen in promastigotes grown to the late logarithmic phase, also characterized by high expression of this peroxiredoxin. Apparently, the physiological role of this peroxiredoxin is stabilization of the mitochondrial membrane potential and, as a consequence, inhibition of PCD through removal of peroxides.

scholarly journals MpeR Regulates themtrEfflux Locus in Neisseria gonorrhoeae and Modulates Antimicrobial Resistance by an Iron-Responsive Mechanism

2012 ◽  
Vol 56 (3) ◽  
pp. 1491-1501 ◽  
Author(s):  
Alexandra Dubon Mercante ◽  
Lydgia Jackson ◽  
Paul J. T. Johnson ◽  
Virginia A. Stringer ◽  
David W. Dyer ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Efflux Pump ◽  
Regulatory System ◽  
Logarithmic Phase ◽  
Free Iron ◽  
Content Type ◽  
Protein Encoding ◽  
Late Logarithmic Phase ◽  
Physiologic Parameters ◽  
Inner Membrane Protein

ABSTRACTPrevious studies have shown that the MpeR transcriptional regulator produced byNeisseria gonorrhoeaerepresses the expression ofmtrF, which encodes a putative inner membrane protein (MtrF). MtrF works as an accessory protein with the Mtr efflux pump, helping gonococci to resist high levels of diverse hydrophobic antimicrobials. Regulation ofmpeRhas been reported to occur by an iron-dependent mechanism involving Fur (ferric uptake regulator). Collectively, these observations suggest the presence of an interconnected regulatory system in gonococci that modulates the expression of efflux pump protein-encoding genes in an iron-responsive manner. Herein, we describe this connection and report that levels of gonococcal resistance to a substrate of themtrCDE-encoded efflux pump can be modulated by MpeR and the availability of free iron. Using microarray analysis, we found that themtrRgene, which encodes a direct repressor (MtrR) ofmtrCDE, is an MpeR-repressed determinant in the late logarithmic phase of growth when free iron levels would be reduced due to bacterial consumption. This repression was enhanced under conditions of iron limitation and resulted in increased expression of themtrCDEefflux pump operon. Furthermore, as judged by DNA-binding analysis, MpeR-mediated repression ofmtrRwas direct. Collectively, our results indicate that both genetic and physiologic parameters (e.g., iron availability) can influence the expression of themtrefflux system and modulate levels of gonococcal susceptibility to efflux pump substrates.

scholarly journals Enzymatic Manganese(II) Oxidation by a Marine α-Proteobacterium

2001 ◽  
Vol 67 (9) ◽  
pp. 4024-4029 ◽  
Author(s):  
Chris A. Francis ◽  
Edgie-Mark Co ◽  
Bradley M. Tebo
Keyword(s):  
San Diego ◽  
Marine Bacterium ◽  
Culture Medium ◽  
Surface Sediments ◽  
Anoxygenic Phototrophic Bacteria ◽  
Logarithmic Phase ◽  
Negative Bacterium ◽  
16S Rrna Analysis ◽  
Aerobic Anoxygenic Phototrophic Bacteria ◽  
San Diego Bay

ABSTRACT A yellow-pigmented marine bacterium, designated strain SD-21, was isolated from surface sediments of San Diego Bay, San Diego, Calif., based on its ability to oxidize soluble Mn(II) to insoluble Mn(III, IV) oxides. 16S rRNA analysis revealed that this organism was most closely related to members of the genus Erythrobacter, aerobic anoxygenic phototrophic bacteria within the α-4 subgroup of theProteobacteria (α-4 Proteobacteria). SD-21, however, has a number of distinguishing phenotypic features relative to Erythrobacter species, including the ability to oxidize Mn(II). During the logarithmic phase of growth, this organism produces Mn(II)-oxidizing factors of ≈250 and 150 kDa that are heat labile and inhibited by both azide ando-phenanthroline, suggesting the involvement of a metalloenzyme. Although the expression of the Mn(II) oxidase was not dependent on the presence of Mn(II), higher overall growth yields were reached in cultures incubated with Mn(II) in the culture medium. In addition, the rate of Mn(II) oxidation appeared to be slower in cultures grown in the light. This is the first report of Mn(II) oxidation within the α-4 Proteobacteria as well as the first Mn(II)-oxidizing proteins identified in a marine gram-negative bacterium.

Effects of oestradiol and progesterone on the alkaline phosphatase activity of a human endometrial cancer cell-line

1980 ◽  
Vol 93 (1) ◽  
pp. 108-113 ◽  
Author(s):  
Mitsuaki Suzuki ◽  
Hiroyuki Kuramoto ◽  
Mieko Hamano ◽  
Hideo Shirane ◽  
Keiichi Watanabe
Keyword(s):  
Alkaline Phosphatase ◽  
Endometrial Cancer ◽  
Cell Growth ◽  
Cell Line ◽  
Growth Pattern ◽  
Cancer Cell Line ◽  
Hormonal Control ◽  
Logarithmic Phase ◽  
Adult Women ◽  
Late Logarithmic Phase

Abstract. The alkaline phosphatase (ALPase) activity of a human endometrial caner cell-line, established and designated as HEC-50-B in our laboratory, was investigated biochemically and histochemically in relation to its cell growth pattern and to the effects of the sex steroid hormones, oestradiol and progesterone. The ALPase activity increased sharply in the early stationary phase to reach an activity almost 2.5 times higher than that obtained in earlier stages of the culture. On administration of oestradiol to the culture medium, a sharp elevation of the ALPase activity was induced on an average of 2 days earlier (late logarithmic phase) than in the case of an ordinary culture (no hormone administration), without causing a notable change in cell growth pattern. It should be noticed, however, that progesterone at such a low concentration that had very little effect on cell growth in the culture could clearly prohibit the elevation of ALPase activity. This hormonal effect on the ALPase activity resembled that on the enzyme activity of the endometrium of adult women. The ALPase activity of both the cultured endometrial cancer cells and the endometrium was found to be a sensitive indicator of the effect of progesterone. It would be a useful tool for future study in elucidating the mechanism of hormonal control of the neoplasm.

Potassium iodate-induced proteolysis in ultra heat treated milk during storage: the role of β-lactoglobulin and plasmin

1986 ◽  
Vol 53 (4) ◽  
pp. 601-613 ◽  
Author(s):  
Mary B. Grufferty ◽  
Patrick F. Fox
Keyword(s):  
Whey Proteins ◽  
Inhibitory Effect ◽  
Casein Micelle ◽  
Ph Optimum ◽  
Heat Treated ◽  
Sh Group ◽  
90 C 30 ◽  
C 30 ◽  
Subsequent Storage ◽  
Β Lactoglobulin

SummaryThe report that addition of KI03 (0·1 mm) to milk before ultra high temperature (UHT) treatment induces extensive proteolysis during subsequent storage at 37 °C was confirmed. None was produced by addition of H202 KMn04 or K2Cr207. The pH optimum for KI03-induced proteolysis was between 7·0 and 8·0 and the temperature optimum 37—45 °C. β-Casein was particularly susceptible and the proteolysis pattern was similar to that caused by indigenous alkaline milk proteinase (MPA, plasmin). Addition of plasmin to milk before UHT treatment (140 °C/10 s) caused slight proteolysis during subsequent storage but addition of 0·1 mm-KI03 and plasmin caused extensive proteolysis which was prevented by addition of soyabean trypsin inhibitor, indicating the probable involvement of plasmin in KI03-induced proteolysis in UHT-treated milk. Equally extensive proteolysis occurred in serum protein-free casein micelle systems (SPFCM), with or without KI03, during storage at 37 °C following UHT treatment, indicating a role for whey proteins in KI03-induced proteolysis. Addition of β-lactoglobulin (β-lg) to a SPFCM system inhibited proteolysis, but extensive proteolysis occurred in a SPFCM system containing both β-lg and KI03. MPA-free Na caseinate (prepared by heating at 140 °C for 7 min) underwent extensive proteolysis when treated with plasmin before UHT treatment; proteolysis was inhibited by addition of °-lg to this system and KI03 reversed the inhibitory effect of β-lg. Plasmin proteolysis of isolated αs1-casein was inhibited by denatured β-lg (90 °C/30 min) at a level of 4 mg/ml but not by native β-lg. When denatured in the presence of KI03, β-lg had a lower free SH content than the control and was less inhibitory for plasmin in proteolysis of isolated αsl-casein. The results show that denatured β-lg inhibits plasmin proteolysis of caseins in UHT milk and that inhibition is prevented by KI03. This inhibition may occur via thiol–disulphide interchange, which is prevented if the SH group of ²-lg is oxidized by KI03, thus permitting the stimulatory effect of KI03 on proteolysis in UHT-treated milk.

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