Intracellular Localization of Several Enzymes in Candida tropicalis Grown on Different Carbon Sources

Intracellular localization of several enzymes related to tricarboxylic acid cycle was investigated during the aerobic growth of Candida tropicalis on acetate, n-alkane and glucose. NADP-linked isocitrate dehydrogenase in acetate-grown cells was mostly found in S₂ fraction (20,000 × g supernatant fraction of protoplast lysate), whereas more than half of this activity in n-alkane-grown cells was recovered in P₂ fraction (20,000 × g pellet fraction). Large parts of NAD-linked isocitrate dehydrogenase and malate dehydrogenase were present in P₂ fraction, while NADP- and NAD-linked glutamate dehydrogenases were found preferentially in S₂ fraction, irrespective of the growth substrates used. Isocitrate lyase was detected in both fractions. Citrate synthase and aconitase in acetate-grown cells were almost particulate. Catalase activity recovered in P₂ fraction was far higher in alkane-grown cells than in acetate- or glucose-grown cells.     

The application of whole-cell protein electrophoresis for the classification and identification of basidiomycetous yeast species

The relationships among 65 basidiomycetous yeast strains were determined by one-dimensional electrophoresis of SDS-solubilized whole-cell proteins. Protein profiles were compared by the Pearson product moment correlation coefficient (r). The strains investigated represented species from the generaCystofilobasidium, Filobasidium, Filobasidiella, Kondoa, Leucosporidium, Mrakia andRhodosporidium. Except for the genusMrakia, all species constituted separate protein electrophoretic clusters. The species of the genusMrakia (M. frigida, M. gelida, M. nivalis andM. stokesii) show highly similar protein patterns, suggesting that these four species may be synonymous. Strains of two varieties ofFilobasidiella neoformans, F. neoformans var.neoformans andF. neoformans var.bacillispora, could not be differentiated by protein electrophoresis.For the delineation of the protein electrophoretic clusters of the yeasts studied, literature data relying on other criteria, such as DNA base composition, carbon source utilization patterns, enzymatic protein electrophoregrams, ubiquinone systems, DNA-DNA homology and rRNA sequence data were used. It was demonstrated that a database of SDS-protein patterns provides a valuable tool for the identification of yeasts.     

T cell–derived exosomes induced macrophage inflammatory protein‐1α/β drive the trafficking of CD8+ T cells in oral lichen planus

Oral lichen planus (OLP) is a T cell–mediated chronic inflammatory disease with uncertain aetiology. Exosomes are nanosized particles with biological capacities. Here, we aimed to study the effects of T cell–derived exosomes (T‐exos) on the pathogenesis of OLP and its mechanism. T‐exos were incubated with Jurkat cells for 48 hours, and 26 cytokines in the supernatant were measured by luminex assay. The expression of macrophage inflammatory protein (MIP)‐1α/β was detected using immunohistochemistry and ELISA; that of CCR1/3/5 on peripheral T cells was determined by flow cytometry. Transwell assay was performed to investigate the chemotactic effect of MIP‐1α/β, and cells in the lower chambers were examinated by flow cytometry. As a result, OLP T‐exos elevated the production of MIP‐1α/β, which were highly expressed in OLP tissues and plasma. CCR1/5 were markedly expressed on OLP peripheral T cells, and the majority of CCR1/5⁺ T cells were CD8⁺ T cells. Besides, MIP‐1α/β promoted the migration of OLP mononuclear cells, while inhibiting CCR1/5 significantly decreased the trafficking of mononuclear cells, especially that of CD8⁺ T cells. Conclusively, OLP T‐exos‐induced MIP‐1α/β may drive the trafficking of CD8⁺ T cells after binding with CCR1/5 in OLP, contributing to the development of OLP.     

Caprolactam waste liquor degradation by various yeasts

Waste liquor from caprolactam manufacture contains many mono- and di-carboxylic acids. Of four yeasts tested, Yarrowia lipolytica DS-1 was the best at decreasing Chemical Oxygen Demand values, by up to 60% with 50 and 100 g waste liquor/after 48 h. Caproic, butyric and valeric acids were utilized most easily. Adipic acid was not decreased below 13% (w/v).The authors are with the Biotechnology Division, Research Centre, Gujarat State Fertilizers Co. Ltd, P.O. Fertilizernagar, Dist. Vadodara, 391 750, India     

A basidiomycetous yeast, Pseudozyma tsukubaensis, efficiently produces a novel glycolipid biosurfactant. The identification of a new diastereomer of mannosylerythritol lipid-B

Mannosylerythritol lipids (MELs) are glycolipid biosurfactants produced by the yeast strains of the genus Pseudozyma. These compounds show not only excellent surface-active properties but also versatile biochemical activities. In the course of MEL production by Pseudozyma tsukubaensis, we found an unusual MEL that had a different carbohydrate structure from that of conventional MELs. The carbohydrate structure was identified as 1-O-beta-D-mannopyranosyl-D-erythritol, and the MEL was confirmed to be 1-O-beta-(2',3'-di-O-alka(e)noyl-6'-O-acetyl-D-mannopyranosyl)-D-erythritol. Interestingly, the configuration of the erythritol moiety in the present MEL was opposite to that of the known MEL-B, 4-O-beta-(2',3'-di-O-alka(e)noyl-6'-O-acetyl-D-mannopyranosyl)-D-erythritol, and to that of all MELs hitherto reported. The present MEL should thus provide different interfacial and biochemical properties compared to conventional MELs.     

Attractiveness of women's body odors over the menstrual cycle: the role of oral contraceptives and receiver sex

It is a long held assumption that women have concealed ovulation,which means that men do not know when women's menstrual cyclesare in their most fertile phase. Recent empirical results haveprovided evidence that ovulation may not be totally concealedfrom pair-bonded males, but the generality and the mechanismsof the finding demand further study. To examine the possibleadaptive value of the phenomenon, it is necessary to study whetherthe ability to detect ovulation is confined to males. We studiedthese questions in an experiment in which male and female ratersrated the sexual attractiveness and intensity of T-shirts' odorsworn by 42 women using oral contraceptives (pill users) andby 39 women without oral contraceptives (nonusers). Males ratedthe sexual attractiveness of nonusers highest at midcycle. However,female raters showed only a nonsignificant trend for this relationship.Neither sex rated attractiveness of the odors of pill usersaccording to their menstrual cycle. The results indicate thatmen can use olfactory cues to distinguish between ovulatingand nonovulating women. Furthermore, the contrasting resultsbetween pill users and nonusers may indicate that oral contraceptivesdemolish the cyclic attractiveness of odors. Together, thesefindings give more basis for the study of the role of odorsin human sexual behavior.     

Candida alocasiicola sp. nov., Candida hainanensis sp. nov., Candida heveicola sp. nov. and Candida musiphila sp. nov., novel anamorphic, ascomycetous yeast species isolated from plants

In a taxonomic study on the ascomycetous yeasts isolated from plant materials collected in tropical forests in Yunnan and Hainan Provinces, southern China, four strains isolated from tree sap (YJ2E(T)) and flowers (YF9E(T), YWZH3C(T) and YYF2A(T)) were revealed to represent four undescribed yeast species. Molecular phylogenetic analysis based on the large subunit (26S) rRNA gene D1/D2 domain sequences showed that strain YJ2E(T) was located in a clade together with Candida haemulonii and C. pseudohaemulonii. Strain YF9E(T) was most closely related to C. azyma and strain YWZH3C(T) to C. sorbophila and C. spandovensis. Strain YYF2A(T) was clustered in a clade containing small-spored Metschnikowia species and related anamorphic Candida species. The new strains differed from their closely related described species by more than 10% mismatches in the D1/D2 domain. No sexual states were observed for the four strains on various sporulation media. The new species are therefore assigned to the genus Candida and described as Candida alocasiicola sp. nov. (type strain, YF9E(T) = AS 2.3484(T) = CBS 10702(T)), Candida hainanensis sp. nov. (type strain, YYF2A(T) = AS 2.3478(T) = CBS 10696(T)), Candida heveicola sp. nov. (type strain, YJ2E(T) = AS 2.3483(T) = CBS 10701(T)) and Candida musiphila sp. nov. (type strain, YWZH3C(T) = AS 2.3479(T) = CBS 10697(T)).     

The Alternative Oxidase of Yarrowia lipolytica Mitochondria Is Unable To Compete with the Cytochrome Pathway for Electrons

The activity of the cyanide-resistant alternative oxidase (pathway) of Yarrowia lipolytica mitochondria was studied as a function of the activity of the major, cyanide-sensitive, cytochrome pathway. The contribution of the alternative oxidase to the total respiration of mitochondria was evaluated by measuring the rate of oxygen consumption in the presence of cyanide (an inhibitor of the cytochrome pathway). The potential activity of the cytochrome pathway was evaluated spectrophotometrically, by measuring the oxidation rate of cytochrome c by ferricyanide, which accepts electrons from complex III (cytochrome c) of this pathway. The oxidation of succinate by mitochondria in the presence of ferricyanide and cyanide was accompanied by oxygen consumption due to the transfer of electrons through the alternative pathway. The subsequent addition of ADP or FCCP (an uncoupler of oxidative phosphorylation in the cytochrome pathway) completely inhibited the consumption of oxygen by the mitochondria. Under these conditions, the inhibition of the alternative pathway by benzohydroxamic acid failed to affect the transfer of electrons from cytochrome c to ferricyanide. Benzohydroxamic acid did not influence the rate of ferricyanide reduction by the cytochrome pathway occurring in controlled state 4, nor could it change the phosphorylation quotient ATP/O upon the oxidation of various substrates. These findings indicate that the alternative pathway is unable to compete with the cytochrome respiratory chain for electrons. The alternative pathway transfers only electrons that are superfluous for the cytochrome chain.