Use of the industrial yeastCandida utilis for cadmium sorption

The sorption ability of Candida utilis biomass for cadmium ions with accumulating competence of dried cells and cells in alginate was compared. After an optimization of process conditions (pH 5.5, biomass concentration 1 g/L and c0 50 mg/L), the cadmium sorption capacity of dried yeast biomass was perceptibly higher than that of the other tested adsorbents. Considering the sorption of the dried yeast biomass equal to 100 %, the cells in alginate reached 86 % while native cells showed only 42 %.     

Production of ethanol by the yeastCandida utilis under autoanaerobic conditions

Candida utilis CCY 29-38-65 converts glucose to ethanol under autoanaerobic conditions. On aeration switch-on the produced ethanol is utilized as carbon source and the specific rate of biomass production increases.     

Substrate dependent bioaccumulation of cadmium by growing yeastCandida utilis

The ability of growing yeastCandida utilis to accumulate cadmium ions from the cultivation broth depends on the carbon source used; xylose and glucose were tested here. For the two substrates, the course of cadmium bioaccumulation and total uptake were quite different. With glucose the maximum of bioaccumulation was about ten times higher than with xylose. The data were consistent with a simple mathematical model of process dynamics which assumes a Freudlich isotherm to describe the biosorption equilibrium and first-order dynamics to simulated the transient state.     

Restoration of respiratory competence in the yeastCandida utilis after somatic fusion withSaccharomyces cerevisiae

After somatic fusion between a mitochondrial mutant ofCandida utilis andSaccharomyces cerevisiae respiratory competent strain, the complex III of the respiratory chain seems to be restored. Fusion products, FP, synthesizing normal apocytochromeb were recovered and showed normal-shaped mitochondria along the cytoplasm as in theCandida utilis original, respiratory-competent strain.     

Assimilation spectrum of the yeastCandida utilis 49 used for producing fodder yeast from synthetic ethanol

Oxidizing and assimilating ability of the yeastCandida utilis 49 was tested with 21 different low-boiling organic compounds which come as components of raw synthetic ethanol. The highest yields of yeast dry weight were obtained with ethanol (72.0%), propanol (48.2%), ethyl acetate (43.4%) and acetic acid (34.2%). To a minor extent, the yeast was capable of utilizing also 2-propanol, butanol and 2-butanol; it oxidized most of the compounds tested.     

Relationship of sulphur metabolism and division ofChlorella pyrenoidosa cells

It was demonstrated that caproic acid inhibits the uptake of phosphate and sulphate byChlorella cells. These findings were used to demonstrate the existence of the previously hypothetical sulphur compound (Tamiyaet al. 1959–1961) essential to the process of division of the alga. A³⁵S-labelled substance was isolated by partition chromatography on a DEAE cellulose column; it was found to be thermolabile and capable of inducing division of the algae even in an inhibited culture. It was also demonstrated that the addition of the substance during the early hours of ontogenetic development shortened the latter by almost half. It can be concluded that the dark phase in the terminal stage of ontogenetic development has a positive effect on the synthesis of this S-substance.     

Novel coiled-coil cell division factor ZapB stimulates Z ring assembly and cell division

Formation of the Z ring is the first known event in bacterial cell division. However, it is not yet known how the assembly and contraction of the Z ring are regulated. Here, we identify a novel cell division factor ZapB in Escherichia coli that simultaneously stimulates Z ring assembly and cell division. Deletion of zapB resulted in delayed cell division and the formation of ectopic Z rings and spirals, whereas overexpression of ZapB resulted in nucleoid condensation and aberrant cell divisions. Localization of ZapB to the divisome depended on FtsZ but not FtsA, ZipA or FtsI, and ZapB interacted with FtsZ in a bacterial two-hybrid analysis. The simultaneous inactivation of FtsA and ZipA prevented Z ring assembly and ZapB localization. Time lapse microscopy showed that ZapB–GFP is present at mid-cell in a pattern very similar to that of FtsZ. Cells carrying a zapB deletion and the ftsZ84 ^ts allele exhibited a synthetic sick phenotype and aberrant cell divisions. The crystal structure showed that ZapB exists as a dimer that is 100% coiled-coil. In vitro , ZapB self-assembled into long filaments and bundles. These results raise the possibility that ZapB stimulates Z ring formation directly via its capacity to self-assemble into larger structures.     

Specific rate of growth of buds related to the genealogical age of the parent cell inCandida utilis

Specific growth rate, specific rate of oxygen consumption calculated per unit cell mass and substrate consumption were followed during the (S + G2) phase of the cell cycle of Candida utilis, when the cell mass increase occurs due to bud growth. Scar-free cells and cells with one and more scars were investigated. Buds of the mother scar-bearing cells grew more slowly. Oxygen was used up at the same rate, whereas glucose was utilized more rapidly.     

A homologue of the bacterial cell division site-determining factor MinD mediates placement of the chloroplast division apparatus

BACKGROUND: Chloroplast division in plant cells occurs by binary fission, yielding two daughter plastids of equal size. Previously, we reported that two Arabidopsis homologues of FtsZ, a bacterial protein that forms a cytokinetic ring during cell division, are essential for plastid division in plants, and may be involved in the formation of plastid-dividing rings on both the stromal and cytosolic surfaces of the chloroplast envelope membranes. In bacteria, positioning of the FtsZ ring at the center of the cell is mediated in part by the protein MinD. Here, we identified AtMinD1, an Arabidopsis homologue of MinD, and investigated whether positioning of the plastid-division apparatus at the plastid midpoint might involve a mechanism similar to that in bacteria. RESULTS: Sequence analysis and in vitro chloroplast import experiments indicated that AtMinD1 contains a transit peptide that targets it to the chloroplast. Transgenic Arabidopsis plants with reduced AtMinD1 expression exhibited variability in chloroplast size and number and asymmetrically constricted chloroplasts, strongly suggesting that the plastid-division machinery is misplaced. Overexpression of AtMinD1 inhibited chloroplast division. These phenotypes resemble those of bacterial mutants with altered minD expression. CONCLUSIONS: Placement of the plastid-division machinery at the organelle midpoint requires a plastid-targeted form of MinD. The results are consistent with a model whereby assembly of the division apparatus is initiated inside the chloroplast by the plastidic form of FtsZ, and suggest that positioning of the cytosolic components of the apparatus is specified by the position of the plastidic components.     

Specific binding of a factor inducing differentiation to mouse myeloid leukemic M1 cells

A factor inducing differentiation of mouse myeloid leukemic M1 cells into macrophages (differentiation-inducing factor, D-factor), which was purified to homogeneity from conditioned medium of mouse Ehrlich ascites tumor cells, could be iodinated without detectable loss of biological activity. The binding of 125I-D-factor to M1 cells was specific; the binding was inhibited competitively by D-factor derived from Ehrlich cells and mouse fibroblast L929 cells, but not by other growth factors or D-factor derived from differentiated M1 cells. The latter differs from D-factor of Ehrlich cells and L929 cells in antigenicity and molecular weight. At 21 degrees C, the binding was saturated at 370 pM 125I-D-factor. M1 cells showed a high affinity for 125I-D-factor (dissociation constant, 1.0 X 10(-10) M) and expressed a small number of binding sites (170 per cell). Specific binding of 125I-D-factor was observed only to several clones derived from M1 cells, including those sensitive and resistant to induction of differentiation by D-factor.     

Biology of the pathogenic yeastCandida glabrata

The yeasts, being favorite eukaryotic microorganisms used in food industry and biotechnologies for production of biomass and various substances, are also used as model organisms in genetic manipulation, molecular and biological research. In this respect, Saccharomyces cerevisiae is the best-known species but current situation in medicine and industry requires the use of other species. Here we summarize the basic taxonomic, morphological, physiological, genetic, etc. information about the pathogenic yeast Candida glabrata that is evolutionarily very closely related to baker's yeast.     

Uridine,a cell division factor in pea roots

Nodulation (root nodule formation) in legume roots is initiated by the induction of cell divisions and formation of root nodule primordia in the plant root cortex, usually in front of the protoxylem ridges of the central root cylinder. We isolated a factor from the central cylinder (stele) of pea roots which enhances hormone-induced cell proliferation in root cortex explants at positions similar to those of nodule primordia. The factor was identified as uridine. Uridine may act as a morphogen in plant roots at picomolar concentrations.     

Specific deficit in the synthesis of 6-sulfoquinovsyl diglyceride in Chlorella pyrenoidosa.

It was found that when Chlorella pyrenoidosa was grown on cysteine as the sole sulfur source, it lost the ability to grow photoautotrophically. When grown in the presence of glucose, cysteine-grown cells displayed a doubling time in the light or dark of 45 h, which is identical to that of cells grown on glucose and SO4 in the dark. This suggests that cells grown on cysteine as sole sulfur source can only grow heterotrophically. In support of this hypothesis, it was found that cysteine-grown cells were defective both in vivo and in vitro in CO2 fixation, although O2 evolution in such cells was normal. Assays of the enzymes of the Calvin cycle indicated that the deficit in CO2 fixation could be ascribed to a lowered phosphoribulokinase activity. A total lipid analysis of Chlorella grown on cysteine revealed that such cells showed a 100-fold deficiency in the purportedly chloroplast-associated 6-sulfoquinovsyl diglyceride. This agrees with earlier reports that cysteine could not serve as a precursor of sulfolipid in Chlorella. No other polar lipid was affected. Large amounts of triglyceride, however, were found in cysteine-grown cells. The biosynthesis of triglyceride provides a means of utilizing reduced nicotinamide adenine dinucleotide reducing equivalents not being used for CO2 fixation.     

Isolation of a factor inducing pole cell formation from Drosophila embryos

Summary

An attempt to isolate an ooplasmic factor active in inducing pole cells in Drosophila embryos is described. With the help of a bioassay system, we demonstrated that RNA extracted from embryos was active in inducing pole cells. These RNA-induced pole cells were morphologically identical to the normal ones. In addition, a local application of cycloheximide suggests that translation in the posterior pole cytoplasm is a precondition for pole cell formation.     

Transport of ribitol and D-glucose in the yeastCandida guillermondii

The uptakes of the linear polyol ribitol and ofd-glucose byCandida guillermondii were found to be carrier-mediated and to require metabolic energy. In glucose-grown cells ribitol possibly enters by simple diffusion but after an induction period a specific transport system is synthesized, inhibitable by higher concentrations of arabinitols, xylitol, mannitol and sorbitol. Actidione blocks the synthesis of the inducible ribitol transport system. Two systems of different affinity for substrate were found to operate in the uptake of both glucose and of ribitol. Counter-transport experiments with ribitol,d-glucose and 3-O-methyl-d-glucose support the carrier nature of the uptake system.     

Phytohormone effects on cell division inChlorella pyrenoidosa chick (TX-7-11-05) (chlorellaceae)

Phytohormone effects on cell division of synchronous cultures ofChlorella pyrenoidosa (TX-7-11-05) were studied under different photo flux densities. The time required for initiation of incipient cell division was reduced significantly by treatment with kinetin (6-furfurylaminopurine), gibberellic acid, and indole-3-acetic acid. Data show that kinetin was more effective than gibberellic acid, which was more effective than indole-3-acetic acid. Studies with combinations of the phytohormones revealed no antagonistic, additive, or synergistic effects.     

Monosaccharides of the green fresh-water algaChlorella kessleri

Both qualitative and quantitative representation of monosaccharides of autotrophically and heterotrophically cultivated algaChlorella kessleri was determined. Potysaccharides obtained after separation of lipids from the alga were subjected to amylolysis and hydrolysis. Individual monosaccharides were determined in the form of per-O-acetylalditols using the method of gas chromatography-mass spectrometry.