Wyniki wyszukiwania - Biblioteka Nauki

1

Biodiversity of Lactococcus lactis bacteriophages in Polish dairy environment

100%

Szczepańska A. K. , Hejnowicz M. S. , Kołakowski P. , Bardowski J.

|

tom 54

|

nr 1

151-158

EN

We present here the results of an exploration of the bacteriophage content of dairy wheys collected from milk plants localized in various regions of Poland. Thirty-three whey samples from 17 regions were analyzed and found to contain phages active against L. lactis strains. High phage titer in all whey samples suggested phage-induced lysis to be the main cause of fermentation failures. In total, over 220 isolated phages were examined for their restriction patterns, genome sizes, genetic groups of DNA homology, and host ranges. Based on DNA digestions the identified phages were classified into 34 distinct DNA restriction groups. Phage genome sizes were estimated at 14-35 kb. Multiplex PCR analysis established that the studied phages belong to two out of the three main lactococcal phage types - c2 and 936, while P335-type phages were not detected. Yet, analyses of bacterial starter strains revealed that the majority of them are lysogenic and carry prophages of P335-type in their chromosome. Phage geographical distribution and host range are additionally discussed.

2

Oddzialywanie bakteriocyn Lactococcus lactis na mikroflore zywnosci

75%

Koterska B. , Oberbek A. , Czarnocka B. , Sliwinska W.

|

nr 04

111-112

3

Purification and characterization of proline-specific peptidases from Lactococcus and Lactobacillus

75%

Stepaniak L.

|

nr 2

EN

Purified proline-specific amino peptidases from Lactobacillus curvatus and from Lactococcus lactis were active on both X-proline dipeptidyl aminopeptidase (PepX) substrates, Gly-Pro-AMC or Gly-PropNA and on proline endopepetidase (PEP) substrates Suc-Gly-Pro-Leu-Gly-Pro, Suc-Gly-Pro-AMC, Z-Gly-Pro-AMC or Suc-Gly-Pro-pNA, however; activity on PEP substrates was markedly less than that on PepX substrates. The enzymes from Lactobacillus and Lactococcus hydrolyzed a number of oligopeptides containing 7-11 amino acids residues and proline at the penultimate position from N-terminus, but hydrolysis of natural PEP oligopeptide substrates containing proline residues at internal positions was negligible. The two proline-specific enzymes were strongly stimulated by NaCl and inhibited by phenylmethylsulfonyl fluoride and organic solvents.

4

Lactococcus lactis IBB477 presenting adhesive and mucoadhesive properties as a candidate carrier strain for oral vaccination against influenza virus

63%

Radziwill-Bienkowska J. M. , Zochowska D. , Bardowski J. , Mercier-Bonin M. , Kowalczyk M.

|

nr 3

5

Selection of Lactococcus lactis strains producing bacteriocins active against pathogenic bacteria

63%

Koterska B. , Czarnocka B. , Sliwinska W. , Oberbek A.

|

tom 07

|

nr 4

723-732

EN

Eleven strains of Lactococcus lacťis synthesising substances of the properties antagonistic toward the strains of the same species were examined. The effect of the strains on pathogenic bacteria: Escherichia coli, Salmonella sp., Staphylococcus aureus and Listeria, monocytogenes was assessed by spot-diffusion method and on a basis of synthesis of inhibitory substance in a liquid medium. Seven out of eleven strains were found to inhibit the growth of the pathogenic bacteria. In the liquid medium only one strain, however, produced the inhibitory substance in the concentration required to inhibit the growth of L. monocytogenes and S. aureus, and, in the same conditions, three strains synthesised the substance of activity against only L. monocytogenes. These substances showed the character of bacteriocins since they did not inhibit the growth of gram-negative bacteria, lost the activity after incubation with proteolytic enzymes, were considerably thermostable in acid and neutral medium, and were inactivated after heating in basic medium. The antibacterial activity of bacteriocins found in this work limits their potential use for preventing the growth of pathogenic L. monocytogenes and S. aureus.

PL

Materiał badań stanowiło 11 szczepów Lactococcus lactis syntetyzujących substancje o właściwościach antagonistycznych wobec szczepów tego samego gatunku. Oddziaływanie badanych szczepów na bakterie chorobotwórcze Escherichia coli, Salmonella sp., Staphylococcus aureus i Listeria monocytogenes oceniano bezpośrednią metodą dyfuzyjno-plamkową oraz na podstawie syntezy substancji hamującej w pożywce płynnej. Stwierdzono, że siedem spośród jedenastu szczepów hamowało wzrost bakterii chorobotwórczych (tab. 1, rys. 1). Jednak w pożywce płynnej tylko jeden szczep wytwarzał substancję hamującą w stężeniu wystarczającym do zahamowania wzrostu Listeria monocytogenes i Staphylococcus aureus, a trzy szczepy w tych samych warunkach syntetyzowały substancję o aktywności ograniczonej do L. monocytogenes (tab. 3). Substancje te posiadały cechy bakteriocyn: nie hamowały wzrostu bakterii gram-ujemnych, traciły aktywność po przetrzymywaniu z enzymami proteolitycznymi oraz charakteryzowały się znaczną termostabilnością w środowisku o odczynie kwaśnym i obojętnym, a ulegały inaktywacji pod wpływem ogrzewania w środowisku alkalicznym (tab. З i 4, rys. 2). Stwierdzona aktywność antybakteryjna bakteriocyn ogranicza ich potencjalne zastosowanie w zapobieganiu rozwojowi chorobotwórczych Listeria monocytogenes i Staphylococcus aureus.

6

Overproduction and purification of the CepA protein from Lactococcus lactis

63%

Kowalczyk M. , Bardowski J.

|

nr 2

EN

In this work we present cloning and overexpression of lactococcal CcpA protein in Escherichia coli Xllblue strain as a fusion with 6xHis tag. A high yield of the CcpA protein was obtained when the cells were cultured in liquid medium LB with 100 ug/ml ampicillin at 37°C and subsequently for 4 h after induction by IPTG. The procedure let us obtain 5 mg of homogenous CcpA protein. Glutaraldehyde crosslinking analysis indicated the formation of dimer or tetramer forms of the CcpA protein.

7

Biodiversity of Lactococcus lactis bacteriophages in Polish dairy environment

63%

Szczepanska A. K. , Hejnowicz M. S. , Kolakowski P. , Bardowski J.

|

tom 54

|

nr 1

EN

We present here the results of an exploration of the bacteriophage content of dairy wheys collected from milk plants localized in various regions of Poland. Thirty-three whey samples from 17 regions were analyzed and found to contain phages active against L. lactis strains. High phage titer in all whey samples suggested phage-induced lysis to be the main cause of fermentation failures. In total, over 220 isolated phages were examined for their restriction patterns, genome sizes, genetic groups of DNA homology, and host ranges. Based on DNA digestions the identified phages were classified into 34 distinct DNA restriction groups. Phage genome sizes were estimated at 14-35 kb. Multiplex PCR analysis established that the studied phages belong to two out of the three main lactococcal phage types - c2 and 936, while P335-type phages were not detected. Yet, analyses of bacterial starter strains revealed that the majority of them are lysogenic and carry prophages of P335-type in their chromosome. Phage geographical distribution and host range are additionally discussed.

8

Nietermiczne metody przedluzania trwalosci zywnosci o malym stopniu przetworzenia

44%

Czapski J. , Limanowka-Jacygrad D.

|

nr 03

27-39

PL

Zapotrzebowanie na produkty żywnościowe o cechach świeżych surowców jest przyczyną rozwoju technologii żywności o małym stopniu przetworzenia. Dla utrwalenia wymaga ona stosowania łagodnego ogrzewania lub zastosowania nietermicznych metod utrwalania. W artykule przedstawiono nietermiczne techniki przedłużania trwałości żywności wraz z niektórymi metodami pakowania.

EN

The development of minimally processed food is the answer of food technologists for the consumer demand for fresh food. This technology requires non-thermal processing or mild heat treatment. Some nonthermal methods of food processing, including packaging methods, were reviewed.

9

Quality of kefir produced using ActiveFlora probiotic

44%

Mituniewicz-Malek A. , Dmytrow I. , Jasinska M.

|

tom 12

|

nr 3

10

Praktyczne sposoby zabezpieczania przed działalnością bakteriofagów przy wyrobie serów

44%

Poznanski S. , Mikitiuk O.

|

tom 16

|

nr 07