A kinetic study on the plasmid stability of three <Emphasis Type="Italic">Lactococcus lactis</Emphasis> strains

Absract The plasmid stability of three wild type Lactococcus lactis strains and their mutants was investigated at different incubation time and temperatures in two different media [M17 broth and reconstituted skim milk (RSM)]. The results showed that both incubation times and temperature are effective on plasmid loss. The plasmid profiles of wild type strains exhibited 8 to 9 distinct plasmid species with molecular weights from 2.1 to 24.0 kb. Lactose fermentation ability was found to be encoded by 22.2 (strain U70), 23.6 (strain U29) and 24.0 (strain U52) kb plasmids in the wild type strains, respectively. The stabilities of the plasmids were explained by applying a second-order polynomial modeling system. Reasonable fittings were obtained for the model and the adjusted regression coefficients (R ² _adj) were between 0.76 and 0.99 for the overall data. Overall, it was found that incubation time had the most profound effect on plasmid stability, with plasmid loss occurring after 72 h, while temperatures in the range of 15–40°C also induced plasmid instability.     

Extended vertical trapezius myocutaneous flap in head and neck reconstruction as a salvage procedure

In surgical treatment of head and neck cancer, when local tumor recurrence or failure of the previous reconstruction method occurs, reoperation for reconstruction of complicated soft-tissue defects can become a challenge for the plastic surgeon. This article describes the authors' experience with the extended vertical trapezius myocutaneous flap for head and neck complicated soft-tissue defects in nine patients ranging in age from 17 to 72 years. The causes of the defects were squamous cell carcinoma of the external ear (n = 2), lip (n = 2), larynx (n = 1), and oral cavity floor (n = 1); congenital hemifacial atrophy-temporomandibular joint ankylosis (n = 1); synovial sarcoma at the mandibular ramus (n = 1); and malignant fibrous histiocytoma at the posterior cranial fossa (n = 1). Eight of the nine patients had previously been operated on using other flap procedures, including free flaps and/or distant pedicled flaps (pectoralis major and deltopectoral flaps). One patient had been operated on using a graft procedure. After failure of the previous flap procedures in four patients and tumor recurrence in five patients, the extended vertical trapezius myocutaneous pedicled flap was used as a salvage procedure. The mean flap size was 7 x 34 cm. The flap was based solely on the transverse cervical artery. Superior muscle fibers of the trapezius were preserved and the caudal end of the flap was extended from 10 to 13 cm beyond the caudal end of the trapezius muscle. Three weeks postoperatively, the pedicle was separated. No flap failure occurred. The donor sites were closed primarily. There were no disabilities with regard to shoulder motion. Tumor recurrence was observed in two patients. In conclusion, for complicated soft-tissue defects of the head and neck, the extended vertical trapezius flap can be preferred as a salvage procedure because it is a simple, reliable, large flap that is located far enough from the damaged area.     

Assessment of antimicrobial activity of nanosized Ag doped TiO2 colloids

In the present research, the antimicrobial effects of nanosized silver (Ag) doped TiO(2) colloidal solutions prepared using a sol-gel technique were investigated. In order to determine the solution characteristics, the turbidity, viscosity and pH of the colloidal solutions were measured. Differential thermal analysis-thermogravimetry equipment was used to determine the chemical structures and reaction types of the films formed from these solutions. The morphology of Ag doped TiO(2) nanoparticles was evaluated by atomic force microscopy. The disc diffusion method was employed to explore antimicrobial activity, and the Broth Microdilution method was used to obtain MIC values of nanosized Ag doped TiO(2) colloidal solutions against the test microorganisms Escherichia coli, Staphylococcus aureus, Candida albicans, Bacillus subtilis, and Salmonella typhimurium. It was found that the silver doped TiO(2) nanoparticles inhibited the growth and multiplication of the test microorganisms, including the fungus C. albicans. Antimicrobial activity was observed against all tested microorganisms at a very low concentration of 1.125-2.81 μg/ml of nano silver in 1-25 % Ag-TiO(2) solutions.     

Microtopography determines the habitat quality of a threatened peatland butterfly at its southern range margin

Knowledge of the ecology of pre-adult stages of an organism at its species’ range margins is a prerequisite for conserving species, especially for understanding its responses to future climate changes. Largely sedentary premature life stages require specific living conditions within a relatively small area. Such conditions are created by vegetation structure heterogeneity and a microclimate gradient, generated by varying microtopography. We investigated the microhabitat selection patterns of egg-laying females and overwintering caterpillars of peatland butterfly Coenonympha tullia relative to vegetation composition, water quantity and microclimatic conditions across microtopographic zones of transition mire at the species’ southern range margin. We showed that (1) small-scale variability in mire microtopography determines oviposition site selection and larval presence; (2) microhabitats of pre-adult stages were largely confined to the intermediate microtopographic zone of the transition mire (flats); (3) egg-laying females and overwintered larvae preferred microsites with high coverage of main hostplants (Trichophorum alpinum, Carex lasiocarpa, C. limosa, C. panicea), and those with more humid and cooler summertime conditions than on hummocks; (4) females and larvae avoided shallow hollows permanently filled with water. The vegetation structure of flats enables the females to select spots with sufficient humidity for egg development, and allows the larvae to change their location according to suitable thermal and moisture conditions. We also discuss poor prospects for species in view of impacts of future climate changes on mire ecosystems.     

Inhibitory effects of dietary flavonoids on purified hepatic NADH-cytochrome b5 reductase: structure-activity relationships

The structure-activity relationships of flavonoids with regard to their inhibitory effects on NADH-cytochrome b5 reductase (E.C. 1.6.2.2), a clinically and toxicologically important enzyme, are not known. In the present study, the inhibitory effects of fourteen selected flavonoids of variable structure on the activity of purified bovine liver cytochrome b5 reductase, which shares a high degree of homology with the human counterpart, were investigated and the relationship between structure and inhibition was examined. Of all the compounds tested, the flavone luteolin was the most potent in inhibiting b5 reductase with an IC50 value of 0.11 μM, whereas naringenin, naringin and chrysin were inactive within the concentration range tested. Most of the remaining flavonoids (morin, quercetin, quercitrin, myricetin, luteolin-7-O-glucoside, (-)-epicatechin, and (+)-catechin) produced a considerable inhibition of enzyme activity with IC50 values ranging from 0.81 to 4.5 μM except apigenin (36 μM), rutin (57 μM) and (+)-taxifolin (IC50 not determined). The magnitude of inhibition was found to be closely related to the chemical structures of flavonoids. Analysis of structure-activity data revealed that flavonoids containing two hydroxyl groups in ring B and a carbonyl group at C-4 in combination with a double bond between C-2 and C-3 produced a much stronger inhibition, whereas substitution of a hydroxyl group at C-3 was associated with a less inhibitory effect. The physiologically relevant IC50 values for most of the flavonoids tested regarding b5 reductase inhibition indicate a potential for significant flavonoid-drug and/or flavonoid-xenobiotic interactions which may have important therapeutic and toxicological outcomes for certain drugs and/or xenobiotics.     

Cytotoxicity and DNA interactions of some platinum(II) complexes with substituted benzimidazole ligands

In the present study, four Pt(II) complexes with 2-ethyl (1)/or benzyl (2)/or p-chlorobenzyl (3)/or 2-phenoxymethyl (4) benzimidazole carrier ligands were evaluated for their in vitro cytotoxic activities against the human HeLa cervix, oestrogen receptor-positive MCF-7 breast, and oestrogen receptor-negative MDA-MB 231 breast cancer cell lines. The plasmid DNA interactions and inhibition of the BamHI restriction enzyme activities of the complexes were also studied. Complex 3 was found to be more active than carboplatin for all examined cell lines and comparable with cisplatin, except for the HeLa cell line.     

Effect of various nerve decompression procedures on the functions of distal limbs in streptozotocin-induced diabetic rats: further optimism in diabetic neuropathy

It is known that diabetic neuropathy is the result of endoneurial edema caused by various biochemical reactions triggered by hyperglycemia. This sequence of events can cause cessation of circulation at the perineurial level, or the tough layer, which is not resilient enough to spread intraneural pressure. Internal and external limiting structures create a double crush phenomenon to the nerve structure. Decompression of the nerve trunk at separate levels is one of the adjuncts to the overall treatment plan for diabetic neuropathy. In this study, the right sciatic nerves of 30 rats with streptozotocin-induced diabetes were used; three groups were created. In the control group, the sciatic nerves were explored and dissected only. In group II, tarsal tunnel release was performed and accompanied by epineurotomy of the sciatic nerve and its peroneal and tibial extensions. In group III, in addition to the procedures performed in group II, perineural sheaths, exposed through the epineurotomy sites at both the peroneal and tibial nerves, were incised for decompression of the fascicles. Improvement in diabetic neuropathy was evaluated by using footprint parameters. The last print length values, estimated according to the 38-month measurements, were 26.1 +/- 0.12 mm in the control group, 23.2 +/- 0.07 mm in group II, and 22.2 +/- 0.1 mm in group III. The toe spread and intermediate toe spread values of the groups were parallel to improvements in print lengths throughout the study. The best improvement was observed in the perineurotomy group. Finally, an electron microscopic study revealed variable degenerative changes in all groups, but they were milder in groups II and III. This experimental study reveals that adding internal decompression to external release doubled the effect in reducing derangement in the sciatic nerves of the rats and, in the authors' opinion, offers cause for further optimism in the treatment of diabetic neuropathy.     

Analysis of Quinolinequinone Analogs with Promising Cytotoxic Activity against Breast Cancer

It is quite challenging to find out bioactive molecules in the vast chemical universe. Quinone moiety is a unique structure with a variety of biological properties, particularly in the treatment of cancer. In an effort to develop potent and secure antiproliferative lead compounds, five quinolinequinones ( AQQ1-5 ) described previously have been selected and submitted to the National Cancer Institute (NCI) of Bethesda to envisage their antiproliferative profile based on the NCI Developmental Therapeutics Program. According to the preliminary in vitro single-dose anticancer screening, four of five quinolinequinones ( AQQ2-5 ) were selected for five-dose screening and they displayed promising antiproliferative effects against several cancer types. All AQQs showed a excellent anticancer profile with low micromolar GI₅₀ and TGI values against all leukemia cell lines, some non-small cell lung and ovarian cancer, most colon, melanoma, and renal cancer, and in addition to some breast cancer cell lines. AQQ2-5 reduced the proliferation of all leukemia cell lines at a single dose and five additional doses, as well as some non-small cell lung and ovarian cancer, the majority of colon cancer, melanoma and renal cancer, and some breast cancer cell lines. This motivated us to use in vitro, in silico, and in vivo technologies to further investigate their mode of action. We investigated the in vitro cytotoxic activities of the most promising compounds, AQQ2 and AQQ3 , in HCT-116 colon cancer, MCF7 and T-47D breast cancer, and DU-145 prostate cancer cell lines, and HaCaT human keratinocytes. Concomitantly, IC₅₀ values of AQQ2 and AAQ3 against MCF7 and T-47D cell lines of breast cancer, DU-145 cell lines of prostate cancer, HCT-116 cell lines of colon cancer, and HaCaT human keratinocytes were determined. AQQ2 exhibited anticancer activity through the induction of apoptosis and caused alterations in the cell cycle. In silico pharmacokinetic studies of all analogs have been carried out against ATR, CHK1, WEE1, CDK1, and CDK2. In addition to this, in vitro ADME and in vivo pharmacokinetic profiling for the most effective AAQ ( AAQ2 ) have been studied.     

Basic Fibroblast Growth Factor Attenuates Bisphosphonate-Induced Oxidative Injury but Decreases Zinc and Copper Levels in Oral Epithelium of Rat

Recent studies have reported oxidative damage due to bisphosphonate (BP) in various cancer tissues and neurons, although basic fibroblast growth factor (bFGF) induced antioxidant effects in the cells. The bFGF may modulate the BP-induced oxidative stress in oral epithelium of rats. This study was undertaken to explore possible beneficial antioxidant effects of bFGF on oxidative stress induced by BP in oral epithelium of rats. Twenty-eight rats were equally divided into four groups. The first group was used as control. The second, third and fourth groups intraperitoneally received BP (zoledronic acid), bFGF and BP + bFGF. At the end of 10 weeks, the rats were sacrificed, and oral epithelium samples were taken for analyses. In BP group, the lipid peroxidation levels were increased in the oral epithelium, while the activities of glutathione peroxidase (GSH-Px) and the concentrations of total antioxidant status (TAS) were decreased. In rats treated with bFGF, lipid peroxidation levels decreased, and the activities of GSH-Px and concentrations of TAS improved in the oral epithelium. However, zinc and copper levels were decreased in the oral epithelium by BP and bFGF treatments. Concentrations of vitamin E and reduced glutathione in the samples did not change in the groups. In conclusion, treatment with bFGF modulated the antioxidant redox system and reduced the oral epithelium oxidative stress induced by BP. However, zinc and copper levels were decreased by BP and bFGF treatments.     

Identification of adsorption inhibition, restriction/modification and abortive infection type phage resistance systems in Lactococcus lactis strains

98 Lactococcus lactis strains were isolated from traditional fermented milk products in Turkey tested against 60 lactococcal lytic phages to determine their resistance levels. While 82 L. lactis strains were sensitive against lactic phages at different levels, 16 L. lactis strains showed resistance to all phages tested. Types of phage resistance among 16 L. lactis strains were identified as phage adsorption inhibition in eight strains, restriction/modification in six strains and abortive infection (heat sensitive phage resistance) in two strains, using three broad-spectrum phages phi pll 98-32, phi pld 67-42 and phi pld 67-44.