Characteristics of the Kabicidin Resistant Mutant of Fusarium sp. Having a High Productivity of Alkaline Protease

In order to elucidate the biochemical mechanism of the alkaline protease accumulation from n-paraffins by a kabicidin-resistant mutant of Fusarium sp., the cell constituents and the extracellular products of the mutant strain were compared with those of the parent strain. No prominent differences in the cell constituents were observed between the parent and the mutant. From the analysis of the extracellular products, however the mutant was found to have a high productivity of some hydrolytic enzymes, such as amylase and ribonuclease, and ergosterol which is a structural constituent of fungal cell membrane. The relationship of secretion of ergosterol, resistance to kabicidin and accumulation of alkaline protease is discussed.     

Purification of Cytochrome a of an L-Glutamate-producing Microorganism,Brevibacterium thiogenitalis

The respiratory chain system of Brev. thiogenitalis grown in the presence of copper ions contained cytochromes a, b and c. The cytochrome a was solubilized and purified from the cell-free extracts by means of Triton X-100 and cholate extraction, and DEAE-cellulose chromatography. It was purified about 130-fold from the cell-free extracts and was free from other cytochromes, The purified preparation contained 1.4 mμatom copper and 1.9 mμatom iron per mμmole heme a, respectively, and approximately 5 mμmoles heme a per mg protein.     

Role of Copper Ions in the Regulation of L-Glutamate Biosynthesis

Cell-free extracts of Brevibacterium thiogenitalis culture grown in the presence of copper catalyzed the oxidation of NADH₂ and succinate through an electron transport chain which contained menaquinones and cytochromes a, b and c. On the other hand, extracts of cells grown in the absence of copper lacked cytochromes a and c, and contained cytochrome d.

These findings, as well as the results obtained in inhibition experiments, suggest that in copper-deficient cells the major part of NADH₂ was oxidized via a bypass in which the electrons were transferred directly from flavoprotein or cytochrome b to molecular oxygen.

Electron transport from these substrates to molecular oxygen resulted in ATP synthesis. The average P/O ratios in extracts of the copper-sufficient cells were 0.33 for generated NADH₂, 0.20 for added NADH₂, and 0.34 for succinate, and those in extracts of the copper-deficient cells were 0.15, 0.13 and 0.21, respectively. In addition, a linear relationship was found between the yield of L-glutamate from acetate and the P/Ο ratios with both NADH₂ and succinate as substrates.

From these results, it is reasonable to consider that the poor yield of L-glutamate from acetate in copper-deficient cells was due to a reduction in energy supply, which was caused by the low efficiency of oxidative phosphorylation.     

Biotransformation of 3-(3′,5′ -Dichlorophenyl)-5,5-dimethyl oxazolidine-2,4-dione

Using 3-(3′,5′-dichlorophenyl)-5,5-dimethyloxazolidine-2,4-dione labeled with ¹⁴C or ³H, absorption, excretion, and tissue distribution in male Wistar rats were studied, and metabolites excreted were identified. At the dosage rates of 100, 300, 1000 and 3000 mg/kg, the maximum excretion of orally administered radioactivity occurred within 24 hr. Increase in the dosage rate was paralleled by decrease in the proportion of urinary elimination. Essentially all the radioactivity was excreted in 2 weeks. DDOD level was generally low in most tissues. Adipose tissue contained higher radioactivity compared with others. Most of the urinary metabolites identified were characterized by hydroxylation at the 4′ position of the benzene ring moiety, and hydrolytic or oxidative modification of the oxazolidine ring portion.     

Conversions of Microbial Products in Relation to Oxygen Supply in Inosine Fermentation

On the basis of the ratio (cell’s respiration rate/maximum oxygen demand of cells, r_{a b}/K_rM) as a new criterion of oxygen supply, symptoms of oxygen deficiency was described in inosine fermentation. Conversions of the products were observed to occur in relation to the extent of oxygen deficiency. When oxygen demand of the cells was satisfied (r_{a b}/K_rM = 1.0), the cells accumulated exclusively inosine. Under limited oxygen supply at the value of r_{a b}/K_rM 0.5~0.9, on the other hand, inosine formation was inhibited and acetoin was the predominant product. When oxygen supply was limited more strictly at the value of r_{a b}/K_rM smaller than 0.3, the cells excreted 2,3-butyleneglycol as the main product.     

Studies on Production of Biotin by Microorganisms

In a preceding paper we reported that Rhodotorula flava 194 effectively converted biotin to biotinamide. In a present paper the metabolism of desthiobiotin by R. flava 194 was studied under the same condition as in the conversion of biotin to biotinamide. Two desthiobiotin derivatives (Vitamer I and II) were isolated. Vitamer II (crystalline) was identified as bisnordesthiobiotin and Vitamer I was chromatographically determined as desthiobiotinamide.     

Psychological stress contributed to the development of low-grade fever in a patient with chronic fatigue syndrome: a case report

Background

Low-grade fever is a common symptom in patients with chronic fatigue syndrome (CFS), but the mechanisms responsible for its development are poorly understood. We submit this case report that suggests that psychological stress contributes to low-grade fever in CFS.

Case presentation

A 26-year-old female nurse with CFS was admitted to our hospital. She had been recording her axillary temperature regularly and found that it was especially high when she felt stress at work. To assess how psychological stress affects temperature and to investigate the possible mechanisms for this hyperthermia, we conducted a 60-minute stress interview and observed the changes in the following parameters: axillary temperature, fingertip temperature, systolic blood pressure, diastolic blood pressure, heart rate, plasma catecholamine levels, and serum levels of interleukin (IL)-1β and IL-6 (pyretic cytokines), tumor necrosis factor-α and IL-10 (antipyretic cytokines). The stress interview consisted of recalling and talking about stressful events. Her axillary temperature at baseline was 37.2°C, increasing to 38.2°C by the end of the interview. In contrast, her fingertip temperature decreased during the interview. Her heart rate, systolic and diastolic blood pressures, and plasma levels of noradrenaline and adrenaline increased during the interview; there were no significant changes in either pyretic or antipyretic cytokines during or after the interview.

Conclusions

A stress interview induced a 1.0°C increase in axillary temperature in a CFS patient. Negative emotion-associated sympathetic activation, rather than pyretic cytokine production, contributed to the increase in temperature induced by the stress interview. This suggests that psychological stress may contribute to the development or the exacerbation of low-grade fever in some CFS patients.

     

Aberrant Glycogen Synthase Kinase 3β Is Involved in Pancreatic Cancer Cell Invasion and Resistance to Therapy

Background and Purpose

The major obstacles to treatment of pancreatic cancer are the highly invasive capacity and resistance to chemo- and radiotherapy. Glycogen synthase kinase 3β (GSK3β) regulates multiple cellular pathways and is implicated in various diseases including cancer. Here we investigate a pathological role for GSK3β in the invasive and treatment resistant phenotype of pancreatic cancer.

Methods

Pancreatic cancer cells were examined for GSK3β expression, phosphorylation and activity using Western blotting and in vitro kinase assay. The effects of GSK3β inhibition on cancer cell survival, proliferation, invasive ability and susceptibility to gemcitabine and radiation were examined following treatment with a pharmacological inhibitor or by RNA interference. Effects of GSK3β inhibition on cancer cell xenografts were also examined.

Results

Pancreatic cancer cells showed higher expression and activity of GSK3β than non-neoplastic cells, which were associated with changes in its differential phosphorylation. Inhibition of GSK3β significantly reduced the proliferation and survival of cancer cells, sensitized them to gemcitabine and ionizing radiation, and attenuated their migration and invasion. These effects were associated with decreases in cyclin D1 expression and Rb phosphorylation. Inhibition of GSK3β also altered the subcellular localization of Rac1 and F-actin and the cellular microarchitecture, including lamellipodia. Coincident with these changes were the reduced secretion of matrix metalloproteinase-2 (MMP-2) and decreased phosphorylation of focal adhesion kinase (FAK). The effects of GSK3β inhibition on tumor invasion, susceptibility to gemcitabine, MMP-2 expression and FAK phosphorylation were observed in tumor xenografts.

Conclusion

The targeting of GSK3β represents an effective strategy to overcome the dual challenges of invasiveness and treatment resistance in pancreatic cancer.