Continuous nisin production with bioengineered Lactococcus lactis strains.

Nisin production in continuous cultures of bioengineered Lactococcus lactis strains that incorporate additional immunity and regulation genes was studied. Highest nisin activities were observed at 0.2 h(-1) dilution rate and 12.5 g l(-1) fructose concentration for all strains. Recombinant strains were able to produce greater amounts of nisin at dilution rates below 0.3 h(-1) compared to the control strain. However, this significant difference disappeared at dilution rates of 0.4 and 0.5 h(-1). For the strains LL27, LAC338, LAC339, and LAC340, optimum conditions for nisin production were determined to be at 0.29, 0.26, 0.27, and 0.27 h(-1) dilution rates and 11.95, 12.01, 11.63, and 12.50 g l(-1) fructose concentrations, respectively. The highest nisin productivity, 496 IU ml(-1) h(-1), was achieved with LAC339. The results of this study suggest that low dilution rates stabilize the high specific nisin productivity of the bioengineered strains in continuous fermentation. Moreover, response surface methodology analysis showed that regulation genes yielded high nisin productivity at wide ranges of dilution rates and fructose concentrations.

Influence of growth conditions on the nisin production of bioengineered Lactococcus lactis strains.

Nisin production of three bioengineered strains, (LAC338, LAC339 and LAC340) with immunity (nisFEG) and/or regulation (nisRK) genes of nisin biosynthesis on plasmids in the Lactococcus lactis LL27 nisin producer, was evaluated under pH-controlled and pH-uncontrolled batch fermentations. Optimization studies showed that fructose and yeast extract yielded the highest nisin activity. The strains LAC338, LAC339, and LAC340 produced 24, 45, and 44% more nisin, respectively, than wild-type L. lactis LL27 after 12-h incubation. However, sharp decreases in the yield of nisin were observed at the late phase of fermentation with LAC339 and LL27 in contrast to LAC340 and LAC338 strains for which the high level of nisin could be maintained longer. Obviously, increasing the copy number of the regulation genes together with immunity genes in the nisin producers retarded the loss of nisin in the late phase of the fermentation.

The evaluation of physician patterns of practice in cardiac patients at two British Columbia tertiary referral hospitals.

OBJECTIVE: To evaluate the patterns of care in patients hospitalized with acute coronary syndrome or congestive heart failure. DESIGN: A pilot study - retrospective chart review. SETTING: Two British Columbia tertiary referral teaching hospitals. PATIENTS: One hundred patients admitted with stable angina, acute ischemic syndrome or congestive heart failure at each hospital. RESULTS: Patient profiles showed that women at both hospitals were significantly older and had significantly longer lengths of stay than men. Patterns of practice were comparable except when it came to lipid testing and lipid-lowering agents being prescribed to patients at the time of discharge. At hospital A, patients were more likely to have a lipid profile performed compared with patients at hospital B. CONCLUSIONS: The addition of lipid testing to the clinical pathway for patients with myocardial infarction led to more patients at hospital A having a lipid profile performed. The routine assessment of lipid profiles in patients admitted for acute ischemic syndromes led to more aggressive pharmacological treatment with hydroxy-methyl-glutaryl coenzyme A reductase inhibitors - agents that are known to reduce mortality and recurrent infarction. Methods to improve treatment are proposed to help reduce morbidity and/or mortality in patients with ischemic heart disease and congestive heart failure.

Individualized stress management for primary hypertension: a randomized trial.

OBJECTIVE: To test the efficacy of individualized stress management for primary hypertension in a randomized clinical trial with the use of ambulatory blood pressure (BP) measures. METHODS: Men and women aged 28 to 75 years with mean ambulatory BP greater than 140/90 mm Hg received 10 hours of individualized stress management by means of semistandardized treatment components. They were randomly assigned to immediate treatment (n = 27) or a wait list control group (n = 33). Participants on the wait list were subsequently offered treatment. Six-month follow-up data were available from 36 of the 45 participants who completed treatment. Measures were 24-hour ambulatory BP, lipid levels, weight, and psychological measures. RESULTS: Blood pressure was significantly reduced in the immediate treatment group and did not change in control subjects (-6.1 vs +0.9 mm Hg for systolic and -4.3 vs +0.0 mm Hg for diastolic pressure). When the wait list control group was later treated, BP was similarly reduced by -7.8 and -5.2 mm Hg, and for the combined sample, total change at follow-up was -10.8 and -8.5 mm Hg. Level of BP at the beginning of treatment was correlated with BP change (r = 0.45 [P<.001] and 0.51 [P<.001], respectively), and amount of systolic BP change was positively correlated with reduction in psychological stress (r = 0.34) and change in anger coping styles (r = 0.35-0.41). CONCLUSIONS: Individualized stress management is associated with ambulatory BP reduction. The effects were replicated and further improved by follow-up. Reductions in psychological stress and improved anger coping appear to mediate the reductions in BP change.

Antagonistic effect on Listeria monocytogenes and L. innocua of a bacteriocin-like metabolite produced by lactic acid bacteria isolated from sucuk.

Two Lactobacilli and four Pediococci strains producing bacteriocin-like metabolities isolated from sucuk were tested with agar spot tests and well diffusion assays for their inhibitory activity against 16 Listeria strains, also isolated from sucuk. The production of organic acids and hydrogen peroxide limited, L. sake Lb 706 (used as a bacteriocin producer strain) and the isolated lactic acid bacteria (LAB) showed inhibitory activity against all of the Listeria strains, while L. sake Lb 706-A (used as a bacteriocin non-producer mutant) had the same effects against only two Listeria monocytogenes strains (51, 52) in agar spot tests. In the well diffusion assays, while L sake Lb 706 and four Pediococci isolates (413, 416, 419, 446) exhibited inhibitory activity against all of the Listeria strains tested, L. sake Lb 706-A and two of the Lactobacilli isolates (77, 116) showed no effect on the Listeria strains tested.

Production of bacteriocin-like metabolites by lactic acid cultures isolated from sucuk samples.

A total of 51 sucuk samples, obtained from different regions of Turkey, were examined for lactic acid bacteria (LAB) strains producing putative bacteriocin-like metabolites. For detection of antagonistic activity, agar spot and well diffusion assay tests were used. Lactobacillus sake Lb790, Listeria monocytogenes Li6, Staphylococcus aureus St44 and Escherichia coli NRRL B-3704 were used as indicator organisms. Strains having antimicrobial activity were also tested against Clostridium perfringens 4TTK, Clostridium botulinum type A. 7948, Bacillus cereus NRRL B-3711, Micrococcus luteus NRRL B-4376 and Yersinia enterocolitica type 103. 57 of 424 isolates from sucuk samples were putative producers of bacteriocin-like metabolistes and were identified as the following: 19 Lactobacillus plantarum, 4 L. curvatus, 4 Pediococcus pentosaceus, 3 P. acidilactici, 2 L. pentosus, 2 L. sake, 1 L. delbrueckii, 1 L. rhamnosus and 21 unidentified Lactobacillus spp. P. pentosaceus 416, P. acidilactici 413, 419 and 446, L. curvatus 348, L. plantarum 452 and 495, and Lactobacillus spp. 411 strains have the best potential for use as sucuk starter cultures.

The psychology of men and women recovering from coronary artery bypass surgery.

BACKGROUND: Little is known about the differences between men's and women's cardiac rehabilitation processes. What helps men during recovery may not necessarily aid women's recovery. Psychosocial variables are known to impact recovery in positive and negative ways. Unfortunately, it is not clear what variables are the most effective predictors of recovery outcomes for men and women. METHODS: Ninety coronary artery bypass graft patients (60 men, 30 women) completed a battery of psychological questionnaires on or after the third day after surgery. RESULTS: Results showed that women reported significantly more depressive symptoms than men. For women, pain was correlated positively with depressive symptomatology and functional impairment. For men, pain and functional impairment were correlated negatively with social support. In addition, the results of a multiple regression of pain on age, severity of disease, and two psychosocial variables (depressive symptomatology and social support) for the women showed that after controlling for age and severity of disease, depressive symptomatology and social support accounted for a significant 43% increment in the variance in pain. The psychosocial variables accounted for much less variance in pain in men. However, in a multiple regression of functional impairment on the same variables, depressive symptomatology and social support accounted for a significant 14% increment in the variance in pain in men but a nonsignificant increment for the women. CONCLUSIONS: The results support the notion that psychosocial variables play different roles in the recovery paths of men and women. In consequence, cardiac rehabilitation programs would be more effective with gender-specific tailoring.

Some characteristics of lactic acid bacteria present in commercial sucuk samples.

A total of 10 sucuk samples, obtained from Denizli, Turkey were analysed for some physical, chemical and microbiological characteristics. In addition, lactic acid bacteria (LAB) strains producing bacteriocin-like metabolites were isolated and identified. The production of some typical metabolites of the cultures isolated was investigated. At the end of the research, the average values of the pH, water and fat content were 5.1, and 37.2% and 30.5%, respectively. Microbiological analyses results were determined: average 8.34 log CFU/g TAMB, 8.91 log CFU/g LAB (at the MRS agar) and average 8.25 log CFU/g LAB (at the Elliker's lactic agar). The average counts of yeast-mould, coliform and Enterobacteriaceae were found to be 5.0 log CFU/g, 3.28 log CFU/g and 3.27 log CFU/g, respectively. In this study, counts of yeast-mould in the two samples, coliform counts in the five samples, and Enterobacteriaceae counts in the three samples were < 1.0 log CFU/g. A total of 6 of 100 LAB isolates obtained from the sucuk samples were found as a strain producing bacteriocin-like metabolites. These 6 strains were identified as follows; 3 strains Lactobacillus plantarum and 3 strains Pediococcus pentosaceus. According to the findings, these strains have the potential to be used as a sucuk starter culture. Additionally, acid and flavour compounds, other undesirable metabolite-producing activities of the strains, were determined in the model system. From these results it was concluded, after the determination of the toxicological properties, that the 4 strains of LAB identified (L. plantarum 13 P. pentosaceus 15 P. pentosaceus 74 and P. pentosaceus 75) would be useful as the starter and protective culture in the processing of the sucuk and similar fermented products.

Effects of Different Fruits and Storage Periods on Microbiological Qualities of Fruit-Flavored Yogurt Produced in Turkey.

Comparative microbiological analyses of fruit-flavored yogurt, plain yogurt, and plain yogurt with 8% sugar were conducted in this research. The fruit-flavored yogurts were produced from evaporated cow's milk (19.75% dry matter) containing 16% jam prepared with an equal weight of sugar and fruit (sour cherry, orange, strawberry, or banana). The total plate count, lactic acid and coliform bacteria, and yeast and mold counts were determined in yogurt samples stored for 1, 3, 5, 7, 9, and 13 days. In conclusion, it is suggested that these types of yogurt should not be stored longer than 7 days, because when a carryover culture is used for yogurt production, most likely yeast contamination will occur. Otherwise, pure starter culture should be utilized in yogurt production.