Nisin production of Lactococcus lactis N8 with hemin‐stimulated cell respiration in fed‐batch fermentation system

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     

First Report of the Occurrence of Grapevine leafroll‐associated virus‐5 in Turkish Vineyards

Surveys were made in the main grape growing region (Southeast Anatolia) of Turkey for the occurrence of Grapevine leafroll‐associated virus‐5 (GLRaV‐5). Plant samples with typical leafroll symptoms and mealybugs, Planococcus ficus (Signoret) were used for assessing the occurrence of GLRaV‐5 by RT‐PCR. A 272 bp band representing GLRaV‐5 infection was successfully detected in plants and mealybugs in some vineyards of the Southeast Anatolia region and the virus is the first time reported in Turkish vineyards.     

Effects of bovine milk lactoperoxidase system on some bacteria

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.     

Cutaneous leishmaniasis infection in Balb/c mice using a Leishmania tropica strain isolated from Turkey.

Leishmania tropica, which is endemic in Turkey, is the causative agent of cutaneous leishmaniasis. Leishmania tropica promastigotes (2 x 10(7)) isolated from a patient with dermal leishmaniasis and reproduced in NNN medium were inoculated subcutaneously into the footpads of 10 Balb/c mice. Cutaneous leishmaniasis developed on the footpads of 4 mice approximately 45 days later. Leishmania tropica amastigotes were observed in smear slides and then cultivated in NNN medium. Balb/c mice are a suitable laboratory model for this isolate of L. tropica and thus a source of amastigotes for studies on the immunology, chemotherapy, and pathogenicity of cutaneous leishmaniasis.     

Estimation of the potential fertility based upon non-return rates of bulls: using polyacrylamide gel instead of cervical mucus in the sperm penetration test

In the present study, we aimed to develop a polyacrylamide gel that could be used instead of bovine cervical mucus in the cervical mucus penetration test (CMPT) to obtain coherent and replicable results in bulls. The frozen semen samples of six Holstein bulls, which were divided into two fertility groups as low and high according to their non-return rate (NRR), were used. In this study, the modified CMPT (mCMPT) was carried out within 0.25 mL transparent plastic straws with an inner diameter 1.7 mm. The penetration ability of spermatozoa to bovine cervical mucus and to polyacrylamide gels swollen with two different solutions [NaCl (G1) and PBS (G2)] was compared. For the penetration test, the straws filled with cervical mucus and both gels were dipped into thawed semen samples and incubated at 37 degrees C for 15 min. After the incubation, straws were frozen in liquid nitrogen vapour and stored at -20 degrees C. On the evaluation day, the frozen straws were cut at 1.5-1.75 cm (penetration distance range=PDR1), 3.25-3.5 cm (PDR2) and 5.0-5.25 cm (PDR3), beginning from open-end of the straws. The separated frozen parts were then immediately transferred onto special counting slides by pushing with a mandrel and left to thaw. Thawed samples were covered with cover glass and penetrated spermatozoa in these parts were counted. The relation between the results and fertility of bulls was determined. In the tests performed using mucus, the number of spermatozoa determined in the high fertility group was found to be higher at PDR3 (p<0.0001) compared to the low fertility group, while in G1 spermatozoa number was significantly higher at PDR1 and PDR3 (p<0.0001). However, in G2 medium, no significant difference was observed between either of the fertility groups with respect to spermatozoa number determined at all distance ranges. In the study, we have determined that the gel swollen with NaCl produces better results and this gel can be used instead of bovine cervical mucus for the CMPT. Therefore, we have concluded that the penetration test performed by polyacrylamide gel swollen with NaCl can be a suitable technique for estimation of the potential fertility of bull spermatozoa.     

Insulin and heparin co-immobilized 3D polyester fabrics for the cultivation of fibroblasts in low-serum media

Insulin and/or heparin immobilized/co-immobilized non-woven polyester fabric (NWPF) discs were developed for the cultivation of L929 mouse fibroblasts in low-serum media. At first, NWPF discs were hydrolyzed to obtain a carboxylic acid group-introduced matrix (NWPF-hydrolyzed). Insulin and heparin co-immobilized NWPF (NWPF-insulin-heparin) was prepared by the grafting of PEO onto NWPF-hydrolyzed disc (NWPF-PEO), followed by the reaction first with insulin and then heparin. In the presence of spacer arm, PEO, the amount of immobilized insulin molecules significantly increased from 6.96 to 84.45 microg/cm(2). The amount of heparin bound to the NWPF-PEO (5.93 microg/cm(2)) was higher than that of the insulin immobilized surface (4.59 microg/cm(2)). Insulin and heparin immobilized NWPF discs were observed with fluorescence microscopy by labeling the insulin and heparin with 8-anilino-1-naphthalene sulfonic acid (ANS) or fluorescein isothiocyanate (FITC), respectively. L929 fibroblasts were used to check the cell adhesion and cell growth capabilities of modified NWPF discs in low-serum media (containing 5% fetal bovine serum). Optical photographs showed that after 2nd day of the culture, fibroblastic cells spread along the length of modified fibers, eventually filling the interfiber space. At the end of 6-day growth period, cell yield in the presence of immobilized heparin was a little bit higher than that of the immobilized insulin. Co-immobilized (insulin/heparin) NWPF discs did not accelerate the cell growth as well as insulin or heparin immobilized discs.     

Homozygous mutations in fibroblast growth factor 3 are associated with a new form of syndromic deafness characterized by inner ear agenesis, microtia, and microdontia

We identified nine individuals from three unrelated Turkish families with a unique autosomal recessive syndrome characterized by type I microtia, microdontia, and profound congenital deafness associated with a complete absence of inner ear structures (Michel aplasia). We later demonstrated three different homozygous mutations (p.S156P, p.R104X, and p.V206SfsX117) in the fibroblast growth factor 3 (FGF3) gene in affected members of these families, cosegregating with the autosomal recessive transmission as a completely penetrant phenotype. These findings demonstrate the involvement of FGF3 mutations in a human malformation syndrome for the first time and contribute to our understanding of the role this gene plays in embryonic development. Of particular interest is that the development of the inner ear is completely disturbed at a very early stage--or the otic vesicle is not induced at all--in all of the affected individuals who carried two mutant FGF3 alleles.     

Melatonin treatment for prevention of oxidative stress: involving histopathological changes

This study was undertaken to test the effect of irradiation on the histopathology of the hypothalamus and cerebral cortex. In addition, the probable effects of radiotherapy on the activities of antioxidant enzymes and levels of nitric oxide (NO) in the plasma were investigated as well. The effects of melatonin treatment on radiotherapy-based central nervous system (CNS) damage were also studied. For this purpose, the rats were randomized into four groups. The first group was the control group (sham-exposed group), the second group received only melatonin, the third group was irradiated and the fourth group received both melatonin and irradiation. Plasma samples of rats were collected for measuring the activities of superoxide dismutase (SOD), catalase (CAT) and the levels of NO. 24 h after the interventions, tissue samples were obtained from the hypothalamus and the cerebral cortex for the light microscopic investigations. These tissues were mostly affected by radiation. The results indicated that the application of radiation significantly enhanced the levels of plasma SOD and NO. On the other hand, melatonin pretreatment prevented the decrease in plasma CAT activity induced by irradiation. It was found that the application of melatonin could significantly prevent the irradiation-induced damages. Light microscopic results revealed that the damage of the CNS by radiation was prevented by the application of melatonin.