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61.
The antimicrobial properties of lignin by-products obtained by organic solvent, neutral sulfite semichemical and kraft pulping
were shown in a series of yeasts. Lignin can act as an inhibitor of growth ofSporobolomyces roseus, Candida tropicalis, Trichosporon cutaneum andCandida albicans. Oxidation of all lignin samples tested depresses their inhibitory effects. 相似文献
62.
Regulation of phosphatidylinositol:ceramide phosphoinositol transferase in Saccharomyces cerevisiae. 总被引:1,自引:0,他引:1
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Maximal phosphatidylinositol:ceramide phosphoinositol transferase activity was measured in yeast cells harvested during the exponential phase of growth. The addition of inositol to the growth medium resulted in a twofold increase in IPC synthase activity in cells grown in the presence or absence of exogenous choline. Enzyme activity was not regulated in yeast inositol biosynthesis regulatory mutants by the addition of inositol to the growth medium. 相似文献
63.
S. Weining L. Ko R. J. Henry 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(4):509-513
-Amylases are the key enzymes involved in the hydrolysis of starch in plants. The polymerase chain reaction (PCR) was used to detect polymorphisms in the length of amplified sequences between the annealing sites of two primers derived from published -amy1 gene sequences in barley. These two primers (Bsw1 and Bsw7), flanking the promoter region and the first exon, amplified two PCR fragments in barley. One of the amplified products, with the expected length of 820 bp, appeared together with another shorter PCR band of around 750 bp. This 750-bp fragment seems to be derived from an -amylase gene not reported previously. Both of the PCR products could be amplified from the two-rowed barley varieties tested, including cv Himalaya from which the sequence information was obtained. Five of the six-rowed barley varieties also have the two PCR fragments whereas another two have only the long fragment. These two fragments seem to be unique to barley, neither of them could be amplified from other cereals; for example, wheat, rye or sorghum. These two -amylase fragments were mapped to the long arm of 6H, the location of the -amy1 genes, using wheat-barley addition lines. Amplification of genomic DNA from wild barley accessions with primers Bsw1 and Bsw7 indicated that both of the fragments could be present, or the long and short fragments could be present alone. The results also demonstrated that the genes specifying these two fragments could be independent from each other in barley. The conserved banding pattern of these two fragments in the two-rowed barley varieties implies that artificial selection from these genes may have played an important role in the evolution of cultivated barley from wild barley. 相似文献
64.
Association of a 76 kDa polypeptide with soluble starch synthase I activity in maize (cv B73) endosperm 总被引:2,自引:1,他引:1
Chen Mu Chee Harn Yuan-Tih Ko George W. Singletary Peter L. Keeling Bruce P. Wasserman 《The Plant journal : for cell and molecular biology》1994,6(2):151-159
Soluble starch synthase (SSS) I was purified 361-fold from hand-dissected endosperm tissue of inbred maize (Zea mays, cv. B73) to specific activities ranging between 5 and 9 µmol min−1 mg−1. A key to this purification protocol was the introduction of a size-exclusion chromatography step, a size-based fractionation which provided abundant levels of desalted SSS forms I and II. The native molecular masses calculated for SSS forms I and II were 75.5 kDa and 180 kDa, respectively. SSSI was then further purified by hydrophobic interaction chromatography on Phenyl-Superose and by FPLC on Mono Q. Analysis of column peaks by SDS—PAGE and scanning densitometry revealed that a 76 kDa polypeptide is strongly correlated with SSSI activity. Antibodies were then generated against a 76 kDa polypeptide extracted from starch granules. These antibodies, which were monospecific for the soluble 76 kDa polypeptide, neutralized greater than 90% of SSSI activity, and precipitated the 76 kDa protein. These results establish the 76 kDa protein as an SSSI in the B73 line of inbred maize. An immunologically similar 76 kDa protein also appears to be tightly associated with the starch granule. 相似文献
65.
66.
The promoters of two carboxylases in a C4 plant (maize) direct cell-specific, light-regulated expression in a C3 plant (rice) 总被引:1,自引:1,他引:0
Makoto Matsuoka Junko Kyozuka Ko Shimamoto Yuriko Kano-Murakami 《The Plant journal : for cell and molecular biology》1994,6(3):311-319
C4 plants have two carboxylases which function in photosynthesis. One, phosphoenolpyruvate carboxylase (PEPC) is localized in mesophyll cells, and the other, ribulose bisphosphate carboxylase (RuBPC) is found in bundle sheath cells. In contrast, C3 plants have only one photosynthetic carboxylase, RuBPC, which is localized in mesophyll cells. The expression of PEPC in C3 mesophyll cells is quite low relative to PEPC expression in C4 mesophyll cells. Two chimeric genes have been constructed consisting of the structural gene encoding β-glucuronidase (GUS) controlled by two promoters from C4 (maize) photosynthetic genes: (i) the PEPC gene (pepc) and (ii) the small subunit of RuBPC (rbcS). These constructs were introduced into a C3 cereal, rice. Both chimeric genes were expressed almost exclusively in mesophyll cells in the leaf blades and leaf sheaths at high levels, and no or very little activity was observed in other cells. The expression of both genes was also regulated by light. These observations indicate that the regulation systems which direct cell-specific and light-inducible expression of pepc and rbcS in C4 plants are also present in C3 plants. Nevertheless, expression of endogenous pepc in C3 plants is very low in C3 mesophyll cells, and the cell specificity of rbcS expression in C3 plants differs from that in C4 plants. Rice nuclear extracts were assayed for DNA-binding protein(s) which interact with a cis-regulatory element in the pepc promoter. Gel-retardation assays indicate that a nuclear protein with similar DNA-binding specificity to a maize nuclear protein is present in rice. The possibility that differences in pepc expression in a C3 plant (rice) and C4 plant (maize) may be the result of changes in cis-acting elements between pepc in rice and maize is discussed. It also appears that differences in the cellular localization of rbcS expression are probably due to changes in a trans-acting factor(s) required for rbcS expression. 相似文献
67.
Gary C. du Moulin Zorina Pitkin Yuan-Jin Shen Evelyn Conti Jean Ko Stewart Carla Charles Dylan Hamilton 《Cytotechnology》1994,15(1-3):365-372
Somatic cell and gene therapy involve the application of biological technologies to an individual patient through the use of living cells which provide a therapeutic benefit (Aliski, 1991). Various forms of cellular and gene therapies are being developed and evaluated in an increasing number of clinical trials for congential and acquired disorders. The potential and progress of these therapeutic applications have resulted in an increasing effort by the Food and Drug Administration (FDA) to develop the regulatory framework under which these therapeutic approaches would insure safety and efficacy, the primary mandate of the FDA.Over five years ago Cellcor began to define the parameters, specifications, and conditions relevant to a Quality Assurance/Quality Control (QA/QC) program that has evolved to insure safety and maximize the efficacy of applications of the company'sex vivo technology, autolymphocyte therapy. Autolymphocyte therapy is an outpatient form of somatic cell immunotherapy based upon the infusion of T cells that have been activatedex vivo using a combination of previously generated autologous cytokines and an anti-CD3 monoclonal antibody.We have been able to demonstrate the feasibility for the safe, controlled, and consistent preparation and delivery of a cellular therapy by application of relevant GMP regulations. This presentation reviews aspects of this program and chronicles our experience which at present amounts to over 4400 infusions for over 700 patients. This program provides a high degree of assurance that a cellular therapy program can be carried out in a multisite mode involving hundreds of patients through the strict adherence to cGMP as set forth in existing regulations. It would be prudent that developers of cellular andex vivo gene therapies establish a similar cell processing and QA/QC infrastructure at an early developmental stage to optimize safety and reproducibility and facilitate regulatory review. 相似文献
68.
Kimura Tetsuya; Takeda Shin; Kyozuka Junko; Asahi Tadashi; Shimamoto Ko; Nakamura Kenzo 《Plant & cell physiology》1993,34(2):345-355
A precursor to the 相似文献
69.
Nobuko Naito Evelyn Grace De Jesus Yasumitsu Nakai Tetsuya Hirano 《Cell and tissue research》1993,272(3):429-437
Tissue non-specific alkaline phosphatase is a membrane-bound glycoprotein enzyme which is characterized by its phosphohydrolytic, protein phosphatase, and phosphotransferase activities. This enzyme is distributed virtually in all mammalian tissues, particularly during embryonic development. Its expression is stagespecific and can be demonstrated in the developing embryo as early as the 2-cell stage. It has been suggested that tissue non-specific alkaline phosphatase might play a role in tissue formation. In the study reported here, a genetransfer approach was employed to investigate possible roles for this enzyme by inserting the cDNA for rat tissue non-specific alkaline phosphatase into CHO and LLC-PK1 cells. Permanently transfected cell-lines expressing varying levels of alkaline phosphatase were estblished. The data showed that functional enzyme was expressed in the transfected cells. Cell spreading and attachment were enhanced in transfected CHO cells expressing high levels of tissue non-specific alkaline phosphatase but not in the LLC-PK1 cells. Further, in CHO cells, proliferation was shown to be inversely proportional to the level of the tissue non-specific alkaline phosphatase expression. Homotypic cell association was demonstrated in both alkaline phosphatase-positive and alkaline phosphatase-negative cells in both CHO and LLC-PK1 celllines. Taken together, these findings suggest that in addition to a role in mineralization of bone, tissue nonspecific alkaline phosphatase might also play a role in other cell activities, including those related to differentiation, such as cell-cell or cell-substrate interaction and proliferation. 相似文献
70.
In Saccharomyces cerevisiae, TRK1 and TRK2 are required for high- and low-affinity K+ transport. Among suppressors of the K+ transport defect in trk1 delta trk2 delta cells, we have identified members of the sugar transporter gene superfamily. One suppressor encodes the previously identified glucose transporter HXT1, and another encodes a new member of this family, HXT3. The inferred amino acid sequence of HXT3 is 87% identical to that of HXT1, 64% identical to that of HXT2, and 32% identical to that of SNF3. Like HXT1 and HXT2, overexpression of HXT3 in snf3 delta cells confers growth on low-glucose or raffinose media. The function of another new member of the HXT superfamily, HXT4 (previously identified by its ability to suppress the snf3 delta phenotype; L. Bisson, personal communication), was revealed in experiments that deleted all possible combinations of the five members of the glucose transporter gene family. Neither SNF3, HXT1, HXT2, HXT3, nor HXT4 is essential for viability. snf3 delta hxt1 delta hxt2 delta hxt3 delta hxt4 delta cells are unable to grow on media containing high concentrations of glucose (5%) but can grow on low-glucose (0.5%) media, revealing the presence of a sixth transporter that is itself glucose repressible. This transporter may be negatively regulated by SNF3 since expression of SNF3 abolishes growth of hxt1 delta hxt2 delta hxt3 delta hxt4 delta cells on low-glucose medium. HXT1, HXT2, HXT3, and HXT4 can function independently: expression of any one of these genes is sufficient to confer growth on medium containing at least 1% glucose. A synergistic relationship between SNF3 and each of the HXT genes is suggested by the observation that SNF2 hxt1 delta hxt2 delta hxt3 delta hxt4 delta cells and snf3 delta HXT1 HXT2 HXT3 HXT4 cells are unable to grow on raffinose (low fructose) yet SNF3 in combination with any single HXT gene is sufficient for growth on raffinose. HXT1 and HXT3 are differentially regulated. HXT1::lacZ is maximally expressed during exponential growth whereas HXT3::lacZ is maximally expressed after entry into stationary phase. 相似文献