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31.
Nisin production of Lactococcus lactis N8 with hemin‐stimulated cell respiration in fed‐batch fermentation system
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In this study, nisin production of Lactococcus lactis N8 was optimized by independent variables of glucose, hemin and oxygen concentrations in fed‐batch fermentation in which respiration of cells was stimulated with hemin. Response surface model was able to explain the changes of the nisin production of L. lactis N8 in fed‐batch fermentation system with high fidelity (R2 98%) and insignificant lack of fit. Accordingly, the equation developed indicated the optimum parameters for glucose, hemin, and dissolved oxygen were 8 g L?1 h?1, 3 μg mL?1 and 40%, respectively. While 1711 IU mL?1 nisin was produced by L. lactis N8 in control fed‐batch fermentation, 5410 IU mL?1 nisin production was achieved within the relevant optimum parameters where the respiration of cell was stimulated with hemin. Accordingly, nisin production was enhanced 3.1 fold in fed‐batch fermentation using hemin. In conclusion the nisin production of L. lactis N8 was enhanced extensively as a result of increasing the biomass by stimulating the cell respiration with adding the hemin in the fed‐batch fermentation. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:678–685, 2015 相似文献
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This study analyses the structural, technological performance components and the overall productivity of inland rainbow trout ( Oncorhynchus mykiss ) farms in the Marmara region, Turkey. Of 81 active farms, 36 were small scale (1–10 t year−1 ), 32 medium-sized (11–30 t year−1 ) and 13 large production units (over 30 t year−1 ). Sufficient data for this study were collected from 70 farms for inclusion in the analyses; 59.3% were so-called combined farms (hatchery and grow-out), 37.9% on-growing farms (for market production) and 2.9% producing juvenile fish only for stocking or for supply to grow-out farms. Juvenile fish production was largely conducted on large farms. Capacity utilization (102.8%) of the large farms was most similar to their projected capacity. Many large farms (43.9%) use high-tech utilities and tools. Small farms mostly use concrete ponds whereas most medium and large-scale farms use fiberglass tanks. Medium and large-scale farms were found to be more successful in broodstock management, fertilization, hatching success and survival rate of juvenile fish. Fish stocking density in medium-sized farms (21.8 kg m−3 ) was higher than in small-scale (14.5 kg m−3 ) and large-scale farms (15.5 kg m−3 ). Overall feed conversion ratio for all farms was estimated as 1.2. From the survey results it appears that production capacity planning was calculated more accurately in the projection phase for small and large-scale farms rather than for medium-sized farms. Medium and large-scale farms were more successful in terms of performance (good experience, good structural and technological capabilities). 相似文献
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Elif Şahin Horasan Gülden Ersöz Musa Göksu Feza Otag Ahmet Oner Kurt Sevim Karaçorlu Ali Kaya 《Mycopathologia》2010,170(4):263-268
Objectives
We aimed to asses possible clinically significant differences between C. parapsilosis and other candida species candidemia receiving care in the intensive care unit (ICU) setting.Methods
The study included 118 adult patients diagnosed as candidemia after admission to the ICU of a university hospital between January 2004 and December 2009. Data about demographic characteristics, underlying diseases, and risk factors for ICU-related candidemia were collected.Results
During the study period, 118 patients with candidemia were identified among 2,853 patients admitted into the ICU. Candidemia was seen in 41.4 cases per 1,000 ICU admissions. The overall incidence of candidemia in ICU patients during the study period was 2.09 per 1,000 hospital admissions. Of the isolates, 18.6% were C. albicans and 81.4% were C. non-albicans. The species most frequently isolated was C. parapsilosis (66.1%, 78/118). The distribution of other Candida spp. was as follows: 15 had C. tropicalis (12.7%) and 3 had C. glabrata (2.5%). By Statistical analysis, when patients with candidemia who had C. parapsilosis were compared with other Candida spp., the following factors were found to be significantly associated with C. parapsilosis fungemia; intravascular catheters (p = 0.008), malignity (p = 0.049) and age (p = 0.039). Relationship was found between C. tropicalis and hematologic malignancies (p = 0.001).Conclusions
When infections with a high mortality such as candidemia is suspected in critically ill patients, it is important to know local risk factors and epidemiological distributions of causative agents in selection of empirical and effective antifungal treatment. 相似文献34.
M. Çankaya M. Şişecioğlu Ö. Barış M. Güllüce H. Özdemir 《Applied Biochemistry and Microbiology》2010,46(1):57-60
Bovine lactoperoxidase (LPO) was purified from skimmed milk using amberlite CG-50-H+ resin, CM sephadex C-50 ion-exchange chromatography, and sephadex G-100 gel filtration chromatography. Lactoperoxidase was purified 20.45-fold with a yield of 28.8%. Purity of enzyme checked by sodium dodecyl sulphate-polyacrylamide gel electrophoresis method and a single band was observed. K m was 0.25 mM at 20°C, V max value was 7.95 μmol/ml min at 20°C (pH 6.0). Antibacterial study was done by disk diffusion method of Kirby-Bauer using Mueller-Hinton agar medium with slight modification. Bovine LPO showed high antibacterial activity in 100 mM thiocyanate-100 mM H2O2 medium for some bacteria (Brevibacillus centrosaurus, B. choshinensis, B. lyticum, Cedecea davisae, Chryseobacterium indoltheticum, Clavibacter michiganense pv. insidiosum, Kocuria erythromyxa, K. kristinae, K. rosea, K. varians, Paenibacillus validus, Pseudomonas syringae pv. populans, Ralstonia pickettii, Rhodococcus wratislaviensis, Serratia fonticola, Streptomyces violaceusniger, Vibrio cholerae-nonO1) respectively, and compared with well known antibacterial substances (levofloxacin, netilmicin). LPO system has inhibition effects on all type bacteria and concentration is really important such as LPO-100 mM thiocyanate-100 mM H2O2 system was proposed as an effective agent against many factors causing several diseases. 相似文献
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The pathogenic fungus Aspergillus alliaceus has been shown to have potential for the biocontrol of Orobanche spp. (broomrape), a root parasitic plant. The effectiveness of A. alliaceus in reducing Orobanche infection was analysed using pesta granules prepared with different food formulations. The results showed that pesta granules comprising of fungal mycelia/spore mixtures from liquid and solid culture, sclerotia and fungal mycelia reduced Orobanche infection to a greater extent in below ground conditions when applied early and at high doses before crop sowing. In addition, pesta granules eliminated the risk of broomrape contamination within a 0.2–0.3 cm diameter of the granules. The sclerotial pathogenicity of A. alliaceus was compared with those of other fungi reported in other studies. In addition, some morphological and histological studies on the fungal pathogenicity on broomrape plants after infection are presented. The present study reveals the potential of sclerotial A. alliaceus pesta granule applications for long-term broomrape biocontrol under field conditions. 相似文献
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Mehmet Erşahin Hale Z. Toklu Şule Çetinel Meral Yüksel Can Erzik M. Zafer Berkman Berrak Ç. Yeğen Göksel Şener 《Neurochemical research》2010,35(3):418-428
The neuroprotective effect of alpha lipoic acid (ALA; 100 mg/kg, po), a dithiol antioxidant, on experimentally induced subarachnoid
hemorrhage (SAH) was assessed in Wistar albino rats. Neurological examination scores recorded at the 48th h of SAH induction
were increased in SAH groups, which were accompanied with significant increases in the formation of reactive oxygen species,
DNA fragmentation ratios, malondialdehyde levels and myeloperoxidase activity, while significant decreases in the brain glutathione
content and Na+, K+-ATPase activity were observed. On the other hand, ALA treatment reversed all these biochemical indices as well as SAH-induced
histopathological alterations. Increased brain edema, impaired blood-brain-barrier permeability and neurological scores were
also improved by ALA treatment. The results demonstrate that ALA exerts neuroprotective effects via the enhancement of endogenous
antioxidant enzyme activity, the inhibition of neutrophil accumulation and free radical generation, suggesting a therapeutic
potential in reducing secondary injury after SAH in patients. 相似文献