The vitamin requirements of Candida shehatae for xylose fermentation

Abstract The vitamin requirements of a strain of Candida shehatae for the fermentation of d -xylose was determined using a statistical procedure with a 2³ factorial design. Biotin as well as thiamine exerted a dramatic stimulatory effect on the rate of ethanol production, coupled with a significant improvement in the ethanol yield. The greatest enhancement of the fermentation was found in the presence of both these vitamins. Pyridoxine exerted only a minor effect, but was essential for complete substrate utilization in the absence of either biotin or thiamine. Only biotin caused a significant increase in the growth rate.     

Molecular dynamics simulation in vacuo and in solution of cyclolinopeptide A: a conformational study.

The conformation of cyclolinopeptide A [c-(Pro-Pro-Phe-Phe-Leu-Ile-Ile-Leu-Val)], a naturally occurring peptide with remarkable cytoprotective activity, has been investigated by means of molecular dynamics simulations in various molecular environments. Structural and dynamical properties have been analyzed and compared with those experimentally determined. A detailed analysis of hydrogen bonds is reported.     

Rehydration conditions and viability of freeze-dried lactic acid bacteria

The influence of rehydration conditions on the recovery of 16 species of freeze-dried lactic acid bacteria was investigated. The survival of dried cultures during reconstitution to the wet state was increased by rehydration with small volumes of the medium used for that purpose (0.3 and 0.5 ml). Comparison of rehydration at several times of exposure showed best survival at 10 min for the majority of the species analyzed.     

Effects of Static Magnetic Field Exposure on Plasma Element Levels in Rat

The interaction of static magnetic fields (SMFs) with living organisms is a rapidly growing field of investigation. The magnetic fields (MFs) effect observed with radical pair recombination is one of the well-known mechanisms by which MFs interact with biological systems. SMF influenced cellular antioxidant defense mechanisms by affecting antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT). However, there were insufficient reports about the effects of SMF on macro and trace elements in serum, and the results were contradictory until now. In the current study, 12 rats were divided into two groups, namely as control and exposure group (128 mT and 1 h/day during five consecutive days). The macro and trace element concentrations in serum were examined. No significant difference was observed in the sodium (Na), potassium (K), calcium (Ca), phosphorus (P), and selenium (Se) levels in rat compared to control. By contrast, exposure to SMF showed an increase in the zinc (Zn) level and a decrease in iron (Fe) concentration. Under our experimental conditions, SMF exposure cannot affect the plasma levels of macroelements, while it can disrupt Zn and Fe concentrations in rat.     

An electron spin resonance study on the free radicals produced from aclacinomycin a and its derivatives: analysis of hyperfine structure of the spectra by means of molecular orbital method

Quinone-containing carcinostatics, aclacinomycin A and its derivatives were investigated on the convertibility to free radical under a mild reducing condition. The hyperfine structures of electron spin resonance (ESR) spectra were satisfactorily reproduced by computer simulations, using the hyperfine coupling constants calculated by the Intermediate Neglect of Differential Overlap Molecular Orbital (INDO MO) method. This verifies the reliability of molecular orbital calculations and opens a way to analyze theoretically the correlation between chemical structures and carcinostatic activities. By analyzing hyperfine structures of ESR spectra, the free radical produced from aclacinomycin was identified as a neutral form of semiquinone radical of intact aclacinomycin. Taking into account the previous finding that 7-deoxyaklavinone (C1) is formed reductively by cytochrome P-450 reductase (EC 1.6.2.4; Komiyama et al., 1979), it is postulated that two types of semi-quinone radicals exist in vivo.