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91.
Cellular metabolite analyses by 13C-NMR showed that C. reinhardtii cells assimilate acetate at a faster rate in heterotrophy than in mixotrophy. While heterotrophic cells produced bicarbonate and CO2
aq, mixotrophy cells produced bicarbonate alone as predominant metabolite. Experiments with singly 13C-labelled acetate (13CH3-COOH or CH3-13COOH) supported that both the 13C nuclei give rise to bicarbonate and CO2
aq. The observed metabolite(s) upon further incubation led to the production of starch and triacylglycerol (TAG) in mixotrophy, whereas in heterotrophy the TAG production was minimal with substantial accumulation of glycerol and starch. Prolonged incubation up to eight days, without the addition of fresh acetate, led to an increased TAG production at the expense of bicarbonate, akin to that of nitrogen-starvation. However, such TAG production was substantially high in mixotrophy as compared to that in heterotrophy. Addition of mitochondrial un-coupler blocked the formation of bicarbonate and CO2
aq in heterotrophic cells, even though acetate uptake ensued. Addition of PSII-inhibitor to mixotrophic cells resulted in partial conversion of bicarbonate into CO2
aq, which were found to be in equilibrium. In an independent experiment, we have monitored assimilation of bicarbonate via photoautotrophy and found that the cells indeed produce starch and TAG at a much faster rate as compared to that in mixotrophy and heterotrophy. Further, we noticed that the accumulation of starch is relatively more as compared to TAG. Based on these observations, we suggest that acetate assimilation in C. reinhardtii does not directly lead to TAG formation but via bicarbonate/CO2
aq pathways. Photoautotrophic mode is found to be the best growth condition for the production of starch and TAG and starch in C. reinhardtii. 相似文献
92.
A. S. Rao 《Plant and Soil》1962,17(2):260-266
Summary A comparison of fungal populations in the rhizospheres of eight varieties of peanut grown in a red lateritic soil amended with farmyard manure was made by the dilution-plate technique. There was a marked increase in fungi in the rhizospheres of TMV 2, TMV 4, Pollachi Red and EC 1698, the increase was smaller in Spanish Improved and RS 1 while very little rhizosphere effect was shown by TMV 3 and Pondicherry 8. Age of the plant had a significant influence on numbers of fungi in the rhizosphere. High R/S ratios were obtained when the plants were 30 days old, at which time attained maximum vegetative growth and started to flower. The ratios gradually decreased after that age until the plants were three months old when there was again a small increase. This later rise in fungal populations is interpreted to be due to an increase in microbial activity around dead or senescent roots. No correlation could be established between numbers of root nodules produced by a variety and its rhizosphere effect. Preferential stimulation of certain fungi in the rhizosphere of some of the varieties was noticed. 相似文献
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Summary In this paperTetracoccosporium andDictyoarthrinium are treated.T. cupulatum, D. lilliputeum andD. microsporum are described new, apart from the typeD. sacchari. A key to the known species ofDictyoarthrinium is proposed.Tetracoccosporium, is a maiden report for India. 相似文献
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Sixty-two strains of yeasts, molds and bacteria were screened for lactase (β-D-galactosidase) activity. Strains exhibiting
the enzyme activity were evaluated for cell yield as well as enzyme units available per litre of the medium, per g cell dry
weight and per mg protein of their cell-free extracts. The molds exhibited lowest enzyme activity but highest cell yields,
bacteria produced lowest cell yield and maximum enzyme activity. Cultures exhibiting very high activity among yeasts wereSaccharomyces fragilis (strain 3217) and among bacteriaStreptococcus cremoris (strain H),Lactobacillus bulgaricus (strain RTS and 1373) andLeuconostoc citrovorum (strain 8081). 相似文献
100.
The essential oil from flowers and leaves of Adenocalymma alliaceae (Bignoniaceae) consists almost entirely of diallyl di-, tri-and tetra-sulphide, a mixture formerly encountered within the Allium genus but never before convincingly recognized within the class of dicotyledonous angiosperms. 相似文献