共查询到20条相似文献,搜索用时 31 毫秒
1.
Summary Cultures of Streptomyces flavogriseus produced considerable amounts of xylanase when grown on xylan containing media. Comparatively lower yields of this enzyme were obtained when hay or avicel served as main carbon source, -xylosidase was synthesized intracellularly and appeared less dependent on the fermentation substrate. The strain produced simultaneously various enzymes of the cellulase complex and the xylose induced glucose isomerase. 相似文献
2.
I. S. Maddox K. Spencer J. M. Greenwood M. W. Dawson J. D. Brooks 《Biotechnology letters》1985,7(11):815-818
Summary One strain each of the fungus,Aspergillus
niger, and the yeast,Saccharomycopsis
lipolytica, were investigated for their ability to produce citric acid from the sugars present in hemicellulose hydrolysates.S.
lipolytica produced citric acid as efficiently from mannose as from glucose, but failed to assimilate xylose, arabinose or galactose.A.
niger readily assimilated mannose, xylose and arabinose, and produced citric acid from these sugars although the yields were lower than from glucose. A possible inhibitory effect of arabinose on citric acid production from other sugars was observed usingA.
niger. 相似文献
3.
Summary A 4.1-kb cryptic plasmid, designated pCA134, has been isolated fromClostridium species. In order to develop a vector suitable for transforming saccharolytic clostridia three hybrid plasmids were constructed by inserting pCA134 into pHV32 withEcoRI, orBglII andBamHI. The newly constructed plasmids were propagated inEscherichia
coli and were used to transformBacillus
subtilis andClostridium
acetobutylicum. One of them, pCAB32 (10.1 kb), which contains chloramphenicol acetyltransferase gene and an origin of replication derived from pCA134 was introduced intoB.subtilis andC.acetobutylicum as well asE.coli. 相似文献
4.
Summary Production of ethanol from cellodextrins, as large as cellohexose, byCandida lusitaniae andC. wickerhamii was studied.C. lusitaniae fermented only glucose and cellobiose, whereasC. wickerhamii efficiently fermented cellodextrins. Maximum ethanol yields of 29.2 g/liter from 54 g/liter cellodextrins were achieved byC. wickerhamii in 3–4 days. 相似文献
5.
Comparative evaluation of ethanol production by xylose-fermenting yeasts presented high xylose concentrations 总被引:5,自引:0,他引:5
Summary Three strains ofPichia
stipitis and three ofCandida
shehatae were compared withPachysolen
tannophilus in their abilities to ferment xylose at concentrations as high as 200 g/L when subjected to both aerobic and microaerophilic conditions. Evaluations based on accumulated ethanol concentrations, ethanol productivities, xylose consumption, and ethanol and xylitol yields were determined from batch culture time courses. Of the strains considered,P.stipitis NRRL Y-7124 seemed most promising since it was able to utilize all but 7 g/L of 150 g/L xylose supplied aerobically to produce 52 g/L ethanol at a yield of 0.39 g per gram xylose (76% of theoretical yield) and at a rate comparable to the fastest shown byC.shehatae NRRL Y-12878. For all strains tested, fermentation results from aerobic cultures were more favorable than those from microaerophilic cultures.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned. 相似文献
6.
Surface sterilized seeds and mesocotyls from sterile seedlings from Panicum bisulcatum Thumb., as well as basal parts of leaves and mesocotyls from sterile seedlings, and seeds from Panicum milioides Nees ex. Trin were used as explants to induce callus on a Murashige and Skoog medium supplemented with 2.5 to 10 mg/l of 2,4-D. Subculturing of the white callus from P. milioides and of the brown callus from P. bisulcatum on a medium containing 0.1 mg/l 2,4-D and 10 g/l sucrose led in both species to the appearance of green structures from which plants could be regenerated. Plants were regenerated by an organogenetic process in P. milioides, while P. bisulcatum plants were regenerated both via organogenesis and somatic embryogenesis. 1032 and 94 plants, from P. bisulcatum and P. milioides, respectively, were transferred into soil, and about 90% of them were grown to maturity and set seeds.Abbreviations MS
Murashige and Skoog medium (15)
- 2,4-D
2,4-dichlorophenoxyacetic acid
- IAA
indoleacetic acid 相似文献
7.
Summary ExposingBacillus
subtilis cultures to high concentrations of alkali cations, especially K+, allows efficient transformation by plasmids. The method allows transformation with unfractionated plasmid DNA, monomeric plasmid DNA as well as linear plasmid DNA.B.
subtilis strains, not amenable to natural transformation, were also transformed by the present method. 相似文献
8.
N. J. Moon L. C. Moon L. O. Ely J. A. Parker 《Applied microbiology and biotechnology》1981,13(4):248-250
Summary Wheat was ensiled and periodically analyzed for lactic acid bacteria present. Initially Lactobacillus
plantarum, Leuconostoc
mesenteroides, Lactobacillus
cellobiosus and Streptococcus
lactis predominated. After two to four days enterococci including S.
faecium and S.
bovis were present in high populations as well as Lactobacillus
plantarum. It was concluded that mixed populations of enterococci and L.
plantarum are active in the successful fermentation of wheat silage. 相似文献
9.
Interspecific somatic hybrid plants betweenRudbeckia hirta cv. Marmalade andR.laciniata cv. Irish Eyes were regenerated following the electro-fusion of mesophyll protoplasts ofR.hirta with callus protoplasts ofR.laciniata. A hybrid selection scheme was based on the fact that plant regeneration, from parental protoplasts ofR.hirta, was via shoot regeneration of callus, and only via rhizogenesis forR.laciniata. The other half of the selection strategy was based on the presence of anthocyanin-pigmented roots; a characteristic of theR.hirta parent only. Somatic hybrids were regenerated, via rhizogenesis, alongside normalR.laciniata but were distinguished by the presence of pigmented roots (a feature ofR.hirta). Hybrid plants had a floral morphology that was intermediate as compared to that of the two parents, with an expected somatic chromosome number of 2n=(2x+4x)=74. Pollen viability though was low. Esterase and peroxidase isozyme profiles confirmed the hybrid nature of the regenerated plants with pigmented roots, whilst chloroplast DNA restriction analysis showed that these hybrids had aR.laciniata chloroplast DNA. This demonstration of somatic hybridisation not only opens up the possibility of incorporating novel traits between such ornamentalCompositae species, but provides a selection strategy based on rhizogenesis as the route to plant regeneration coupled with heritable pigmentation production of roots as a confirmatory hybrid marker.ABBREVIATIONS BSA
bovine serum albumin
- EDTA
ethylene diamine tetra acetic acid
- FDA
fluorescein diacetate
- f.wt.
fresh weight
- IAA
indole 3-acetic acid
- MS
Murashige and Skoog (1962) medium
- TEMED
N,N,N,N-Tetra methyl ethylene diamine
- TES
(N-tris (hydroxymethyl) methyl-2-aminoethanesulfonic acid) 相似文献
10.
Following PEG and high pH induced fusion, intraspecific gametosomatic hybrid plants (pollen tetrad protoplasts of a normal purple flowered variety of P. hybrida fused with cell suspension protoplasts of a nuclear albino mutant of the variety Blue Lace) and interspecific gametosomatic hybrid plants (tetrad protoplasts (as above) fused with cell suspension protoplasts of a nuclear albino mutant of P. parviflora) were recovered. Hybrid plants of both combinations possessed an intermediate vegetative and floral morphology with chromosome numbers of 2n=3x=21 and 2n=3x=25 respectively. Hybrid cells were in both systems identified as green colonies against an albino background as a result of complementation to chlorophyll proficiency. Pollen tetrad protoplasts did not divide. The production of such plants at the intra- and interspecific level in Petunia has shown that the concept of gametosomatic hybridisation can be extended to genera other than Nicotiana. An alternative selection strategy is available to that as used earlier for Nicotiana. 相似文献
11.
Summary Plasmids fromZ.
mobilis could be stably maintained inE.
coli HB101 in which the expression of various drug resistance markers could be monitored. A large molecular weight plasmid (5.2 kbp) ofZ.
mobilis was found to harbour the genes for mercuric chloride degradation and to confer uponE.
coli, resistance to a higher mercuric chloride concentration as compared toZ.
mobilis. The introduction of this plamsid madeE.
coli sensitive to concentrations of cadmium acetate which were originally non-inhibitory to it. 相似文献
12.
In our studies with the penicillin V acylase of Bovista plumbea strains NRRL 3501 and NRRL 3824, we wanted to receive spores of these fungi. Surprisingly the fruiting bodies obtained in our work were not identical with
those characteristic for Bovista plumbea. We identified them as Pleurotus ostreatus. For this reason we have to correct the name of the fungi known as Bovista plumbea NRRL 3501 and NRRL 3824. 相似文献
13.
Summary Cell suspension cultures of a Ceratocystis ulmi-resistant (Ulmus pumila) and a -susceptible elm (U.campestris) were established from leaf callus tissue. Treatment of cultures with spores of C.ulmi induced a large increase in the activity of phenylalanine ammonialyase, only in the cells of the resistant species U.pumila with a maximum after 24 h. Inoculated U.pumila cells also excreted a red unidentified chemical into the culture medium. Neither responses were induced in inoculated U.campestris cultures. The results are discussed in relation to the development of the elm cell culture system as a model for studying
the differential biochemical mechanisms of disease resistance in elms. 相似文献
14.
Summary Four species of bacteria which includedPseudomonas
fluorescens,Vibrio
cholerae andVibrio
costicola were observed to produce glutaminase both as extracellular and intracellular fractions. Comparatively both the fractions were higher in mineral media supplemented with 1% glutamine than in nutrient broth added with or without glutamine. Extracellular glutaminase production was about 2.6–6.8 times greater than the intracellular production by all the tested strains. 相似文献
15.
Summary A basic procedure was developed to produce a tempe-like product using the mouldRhizopus
oligosporus and black common beans (Phaseolus
vulgaris) as substrate. The initial pH of the substrate was 5.8, and fermentation was conducted at 37°C with a relative humidity of 70% for 72 hrs. Levels of soluble solids and soluble protein increased dramatically as a result of fermentation. Some changes were as well observed in fatty acid contents of fermented samples. It was concluded that the common bean used was an acceptable substrate for preparing this product. 相似文献
16.
Summary Enzyme synthesis, foaming behaviour and its effects were studied using two common cellulolytic fungi;Trichoderma
reesei andSporotrichum pulverulentum in a medium containing sugar beet cosette as a cellulosic substrate. Cellulase enzyme activities in the culture broth were found to be higher than the enzyme activities in natural and experimentally forced foam layers. 相似文献
17.
Gamil Amin 《Biotechnology letters》1992,14(6):499-504
Summary The possibility of usingZymomonas
mobilis as the microorganism, in solid-state fermentation of sugar-beet particles was investigated. The major factors affecting the process were investigated and related to ethanol yield and productivity. Ethanol yield of 0.48 g/g sugar, volumetric productivity of 12 g/L h, and final ethanol concentration of 130 g/L show the good performance ofZ.mobilis in a solid-state fermentation. 相似文献
18.
E. B. Doerschug 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1976,48(3):119-130
Summary Dotted (Dt) is the regulatory element of a two-unit controlling system in maize. Dt causes the inherited change from the recessive a (colorless) to its dominant allele, A (anthocyanin production), during the development of the stalk, leaves, and endosperm. The mutation events are observed as sectors of color in an anthocyaninless background.Since its discovery over 40 years ago, Dt has always been found in the terminal knob of the short arm of chromosome 9. This is puzzling because controlling and regulatory elements in general are not located permanently, but change positions (transpose) within the chromosomal complement. To resolve this seeming discrepancy, transpositions were looked for in a homozygous a Dt stock. Because the frequency of aleurone mutations is exponentially related to Dt dosage, a Dt transposition would result in a greatly increased number of dots if the egg or sperm nucleus contained both the transposed Dt and the Dt remaining on chromosome 9. A total of 6 transposed Dt's (Dt-T) were recovered in this manner.
Dt-TA was found linked to the gene Y (yellow endosperm) of chromosome 6. Dt-TB no longer showed linkage with yg2 of chromosome 9, but remains unlocated (the original Dt in this stock is separated from yg2 by 6 or 7 cross-over units.). The remaining transpositions (C-F) assorted independently of Dt on chromosome 9.The transposed Dt's had the same effect as Dt on the frequency and timing of aleurone mutations. An increase in transposition frequency and losses of Dt-T's was characteristic of several of the transposed Dt's. Dt-T's B-F transposed so frequently that testcross ratios of 71 (three Dt' s) and 15 1 (four Dt' s) were observed. No secondary transpositions or losses of Dt-TA were detected. Thus, Dt-TA resembles the original Dt with regard to its transposition frequency and stability.Journal Paper No. J-8333 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 1880. 相似文献
19.
Summary An investigation was performed to recognise a fungus capable of 19-hydroxylating the steroids androstenedione, cortexolone and progesterone, in high yield with little or no side reactions. The fungi selected for study belong to a group which has been previously reported to possess 19-hydroxylation ability. Pellicularia filamentasa f. sp. microsclerotia IFO 6298 and P.
filamentosa f.sp. sasakii IFO 5254 both 19-hydroxylated cortexolone, but 19-hydroxylated products were not detected using either androstenedione or progesterone as substrate. When 19-hydroxylating cortexolone, both strains of P.
filamentosa produced 11-hydroxycortexolone as a by-product, but P.
filamentosa f.sp. microsclerotia IFO 6298 was superior in terms of 19-hydroxylation and the relative amounts of the two products. 相似文献
20.
The terminal oxidases of Azotobacter vinelandii 总被引:2,自引:0,他引:2
The terminal respiratory chain of the aerobic nitrogen-fixing bacterium Azotobacter vinelandii was investigated by photochemical action spectra. Terminal cytochrome oxidases a2, a1 and o were confirmed as being the terminal oxidases for the physiological substrates NADH and L-malate. TMPD/ascorbate, not giving coupled phosphorylation uses cytochrome a1 and possibly an o type. DCPIP/ascorbate, giving coupled phosphorylation uses neither cytochrome a1 nor a2. 相似文献