Bacteriophage-resistance mechanisms examined by transfection of Lactococcus lactis subsp. lactis 4513-5 mediated by high voltage electroporation

1992 ◽  
Vol 37 (2) ◽  
Author(s):  
KatjaM. Meyer ◽  
Roland S�ssmuth
Keyword(s):  
Lactococcus Lactis ◽  
High Voltage ◽  
Resistance Mechanisms ◽  
Lactococcus Lactis Subsp ◽  
Bacteriophage Resistance

Growth, nisA Gene Expression, and In Situ Activity of Novel Lactococcus lactis subsp. cremoris Costarter Culture in Commercial Hard Cheese Production

2017 ◽  
Vol 80 (12) ◽  
pp. 2137-2146 ◽  
Author(s):  
Dimitrios Noutsopoulos ◽  
Athanasia Kakouri ◽  
Eleftheria Kartezini ◽  
Dimitrios Pappas ◽  
Efstathios Hatziloukas ◽  
...  
Keyword(s):  
Gene Expression ◽  
Lactococcus Lactis ◽  
Starter Culture ◽  
Fold Increase ◽  
Raw Milk ◽  
Good Growth ◽  
Lactococcus Lactis Subsp ◽  
Quantitative Expression ◽  
Hard Cheese

ABSTRACT This study evaluated in situ expression of the nisA gene by an indigenous, nisin A–producing (NisA+) Lactococcus lactis subsp. cremoris raw milk genotype, represented by strain M78, in traditional Greek Graviera cheeses under real factory-scale manufacturing and ripening conditions. Cheeses were produced with added a mixed thermophilic and mesophilic commercial starter culture (CSC) or with the CSC plus strain M78 (CSC+M78). Cheeses were sampled after curd cooking (day 0), fermentation of the unsalted molds for 24 h (day 1), brining (day 7), and ripening of the brined molds (14 to 15 kg each) for 30 days in a fully controlled industrial room (16.5°C; 91% relative humidity; day 37). Total RNA was directly extracted from the cheese samples, and the expression of nisA gene was evaluated by real-time reverse transcription PCR (qRT-PCR). Agar overlay and well diffusion bioassays were correspondingly used for in situ detection of the M78 NisA+ colonies in the cheese agar plates and antilisterial activity in whole-cheese slurry samples, respectively. Agar overlay assays showed good growth (>8 log CFU/g of cheese) of the NisA+ strain M78 in coculture with the CSC and vice versa. The nisA expression was detected in CSC+M78 cheese samples only, with its expression levels being the highest (16-fold increase compared with those of the control gene) on day 1, followed by significant reduction on day 7 and almost negligible expression on day 37. Based on the results, certain intrinsic and mainly implicit hurdle factors appeared to reduce growth prevalence rates and decrease nisA gene expression, as well as the nisin A–mediated antilisterial activities of the NisA+ strain M78 postfermentation. To our knowledge, this is the first report on quantitative expression of the nisA gene in a Greek cooked hard cheese during commercial manufacturing and ripening conditions by using a novel, rarely isolated, indigenous NisA+ L. lactis subsp. cremoris genotype as costarter culture.

Location and characterization of aminopeptidase N in Lactococcus lactis subsp. cremoris HP

1992 ◽  
Vol 37 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Fred A. Exterkate ◽  
Marian de Jong ◽  
Gerrie J. C. M. de Veer ◽  
Ronald Baankreis
Keyword(s):  
Lactococcus Lactis ◽  
Aminopeptidase N ◽  
Lactococcus Lactis Subsp

Lactococcus lactis subsp. cremoris FC alleviates symptoms of colitis induced by dextran sulfate sodium in mice

2009 ◽  
Vol 9 (12) ◽  
pp. 1444-1451 ◽  
Author(s):  
Yosuke Nishitani ◽  
Takeshi Tanoue ◽  
Katsushige Yamada ◽  
Tsukasa Ishida ◽  
Masaru Yoshida ◽  
...  
Keyword(s):  
Lactococcus Lactis ◽  
Dextran Sulfate ◽  
Dextran Sulfate Sodium ◽  
Lactococcus Lactis Subsp

scholarly journals The effects of Lactococcus lactis subsp. lactis and its supernatant on some bacteriological and sensory values in Rainbow trout (Onchorhynchus mykiss) fillets

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Asad Abbaspour Anbi ◽  
Vadood Razavilar ◽  
Moslem Neyriz Naghadehi ◽  
Masoud Seidgar ◽  
Ali Nekuiefard ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Lactococcus Lactis ◽  
Storage Time ◽  
Culture Medium ◽  
Live Cells ◽  
Human Consumption ◽  
Lactococcus Lactis Subsp ◽  
Live Bacteria ◽  
And Control ◽  
Control Samples

Lactic Acid Bacteria (LAB) have a great potential as bio-preservatives. The live cells and supernatant Lactococcus lactis subsp. lactis induced bacteriological changes in Onchorhynchus mykiss fillet by spray and immersion methods was studied during vacuum- packaged storage at 4 °C for 15 days. 40 kg of O. mykiss were prepared from a culture farm in Oshnavieh (Northwest Iran) and 112 fillet samples (100g) were prepared by aseptic method. L. lactis subsp. lactis (PTCC1336) bacteria was cultured in MRS culture medium. Its supernatant (2%, 4%) was extracted and 106 CFUml-1 dilutions of LAB were prepared and tested on the fillets to enhance their shelf life. All samples were evaluated regarding to growth of psychrotrophic, psychrophilic, mesophilic bacteria, molds and yeasts. Four characteristics including of odor, flavor, texture and color of fillets after and before cooking were evaluated for sensory analysis on days 1, 5, 10 and 15 and compared with control samples. The 4% supernatant and live bacteria were more effective than that of 2% and control (P<0.05). The amounts of corrosive bacteria in 4% and live cells in storage time were less than human consumption limits (7log CFUg-1), whereas in control and 2% supernatant treatments were more than that limits. The results showed that increasing the percentage of supernatant was more effective on bacteriologic factors and enhanced sensory characteristics of rainbow trout fillets (P<0.05).

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