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91.
Victor H. Kollman John L. Hanners Robert E. London Enrique G. Adame Thomas E. Walker 《Carbohydrate research》1979,73(1):193-202
The blue-green alga Agmenellum quadruplicatum (strain PR6) has been used to prepare photobiosynthetically 13C-labeled d-glucose, 2-O-(α-d-glucopyranosyl)-glyceric acid (glucosylglycerate), 2-hydroxy-1-(hydroxymethyl)ethyl α-d-gluco-pyranoside (glucosylglycerol), and α-d-glueopyranosyl β-d-fructofuranoside (sucrose). When grown to a cell density of 4.4 g.L-1 (dry weight) under nitrate-nitrogen limiting growth conditions for 120 h, the algal cells contained 38% of the dry-cell weight as(1 → 4)-α-d-glucan (amylose). About 1% of the dry-cell weight was glucosylglycerol, glucosylglycerate, and sucrose. Glutamate was obtained, together with carbohydrates of low molecular weight, when the cells were extracted with chloroform-methanol; d-glucose was recovered from the extracted cells by acid hydrolysis of the starch. The algae were grown by using 20 mol% [13C] carbon dioxide for preparation of labeled carbohydrates and for cellular component identification by whole-cell n.m.r. spectroscopy. 相似文献
92.
93.
John S. D. Bacon Alex H. Gordon E. Jane Morris Victor C. Farmer 《The Biochemical journal》1975,149(2):485-487
O-Acetyl groups were detected by i.r. spectroscopy in cell-wall preparations from grasses and other higher plants and their presence was confirmed chemically. The amounts present are likely to influence both the physical state of the cell-wall polysaccharides and also their digestion by enzymes. 相似文献
94.
Lizbeth Castro-Concha Victor M. Loyola-Vargas José L. Chan Manuel L. Robert 《Plant Cell, Tissue and Organ Culture》1990,22(2):147-151
Agave tequilana stem explants were used to produce adventitious shoots under a set of different water potentials induced by different concentrations of gelrite in the medium. At high water potentials all shoots were vitrified; as the medium water potential became more negative the degree of vitrification decreased but the number of shoots per explant also diminished. The enzymes NADH and NAD-GDH (EC. 1.4.1.2) were measured along the water potential gradient. GDH activity was high in the non-vitrified tissues and decreased significantly in the vitrified ones.Abbreviations GDH
glutamate dehydrogenase
- MS
Murashige and Skoog medium
- MSO
methionine sulfoximine
- PVP
polyvinylpolypyrrolidone
- GS
glutamine synthetase
- GOGAT
glutamine: oxoglutarate amino transferase 相似文献
95.
Valeri B. Kozhemyako Galina N. Veremeichik Yuri N. Shkryl Svetlana N. Kovalchuk Vladimir B. Krasokhin Valeri A. Rasskazov Yuri N. Zhuravlev Victor P. Bulgakov Yuri N. Kulchin 《Marine biotechnology (New York, N.Y.)》2010,12(4):403-409
Silicatein genes are known to be involved in siliceous spicule formation in marine sponges. Proteins encoded by these genes,
silicateins, were recently proposed for nanobiotechnological applications. We studied silicatein genes of marine sponges Latrunculia oparinae collected in the west Pacific region, shelf of Kuril Islands. Five silicatein genes, LoSilA1, LoSilA1a, LoSilA2, and LoSilA3 (silicatein-α group), LoSilB (silicatein-β group), and one cathepsin gene, LoCath, were isolated from the sponge L. oparinae for the first time. The deduced amino acid sequence of L. oparinae silicateins showed high-sequence identity with silicateins described previously. LoCath contains the catalytic triad of amino acid residues Cys-His-Asn characteristic for cathepsins as well as motifs typical for
silicateins. A phylogenetic analysis places LoCath between sponge silicateins-β and L-cathepsins suggesting that the LoCath gene represents an intermediate form between silicatein and cathepsin genes. Additionally, we identified, for the first time,
silicatein genes (AcSilA and AcSilB) in nonspicule-forming marine sponge, Acаnthodendrilla sp. The results suggest that silicateins could participate also in the function(s) unrelated to spiculogenesis. 相似文献
96.
97.
Stephanos I. Grammatikos Papasani V. Subbaiah Thomas A. Victor William M. Miller 《Cytotechnology》1994,15(1-3):31-50
Fatty acids (FAs) have long been recognized for their nutritional value in the absence of glucose, and as necessary components of cell membranes. However, FAs have other effects on cells that may be less familiar. Polyunsaturated FAs of dietary origin (n–6 andn–3) cannot be synthesized by mammals, and are termed essential because they are required for the optimal biologic function of specialized cells and tissues. However, they do not appear to be necessary for normal growth and metabolism of a variety of cells in culture. The essential fatty acids (EFAs) have received increased attention in recent years due to their presumed involvement in cardiovascular disorders and in cancers of the breast, pancreas, colon and prostate. Manyin vitro systems have emerged which either examine the role of EFAs in human disease directly, or utilize EFAs to mimic thein vivo cellular environment. The effects of EFAs on cells are both direct and indirect. As components of membrane phospholipids, and due to their varying structural and physical properties, EFAs can alter membrane fluidity, at least in the local environment, and affect any process that is mediated via the membrane. EFAs containing 20 carbons and at least three double bonds can be enzymatically converted to eicosanoid hormones, which play important roles in a variety of physiological and pathological processes. Alternatively, EFAs released into cells from phospholipids can act as second messengers that activate protein kinase C. Furthermore, susceptibility to oxidative damage increases with the degree of unsaturation, a complication that merits consideration because lipid peroxidation can lead to a variety of substances with toxic and mutagenic properties. The effects of EFAs on cultured cells are illustrated using the responses of normal and tumor human mammary epithelial cells. A thorough evaluation of EFA effects on commercially important cells could be used to advantage in the biotechnology industry by identifying EFA supplements that lead to improved cell growth and/or productivity.Abbreviations AA
arachidonic acid (20 carbons: 4 double bonds,n–6)
- BHA
butylated hydroxyanisole
- BHT
butylated hydroxytoluene
- cAMP
cyclic adenosine monophosphate
- CHO
Chinese hamster ovary
- DAG
diacylglycerol
- DGLNA
dihomo--linolenic acid (203,n–6)
- DHA
docosahexaenoic acid (226,n–3)
- EFA
essential fatty acid
- EGF
epidermal growth factor
- EGFR
epidermal growth factor receptor
- EPA
eicosapentaenoic acid (205,n–3)
- FA
fatty acid
- FBS
fetal bovine serum
- GLNA
-linolenic acid (183,n–6)
- LA
linoleic acid (182,n–6)
- LNA
-linolenic acid (183,n–3)
- LT
leukotriene
- MDA
malondialdehyde
- NAD
nicotinamide adenine dinucleotide
- NDGA
nordihydroguaiaretic acid
- OA
oleic acid (181,n–9)
- PG
prostaglandin
- PKC
protein kinase C
- PUFA
polyunsaturated fatty acid
- SFM
serum-free medium
- TX
thromboxane 相似文献
98.
99.
Yoon-Jeong Park Jin Chang Pen-Chung Chen Victor Chi-Min Yang 《Biotechnology and Bioprocess Engineering》2001,6(5):326-331
With the aim of developing a pH-sensitive controlled drug release system, a poly (L-lysine) (PLL) based cationic semi-interpenetrating polymer network (semi-IPN) has been synthesized. This cationic hydrogel
was designed to swell at lower pH and de-swell at higher pH and therefore be applicable for achieving regulated drug release
at a specific pH range. In addition to the pH sensitivity, this hydrogel was anticipated to interact with an ionic drug, providing
another means to regulate the release rate of ionic drugs. This semi-IPN hydrogel was prepared using a free-radical polymerization
method and by crosslinking of the polyethylene glycol (PEG)-methacrylate polymer through the PLL network. The two polymers
were penetrated with each other via interpolymer complexation to yield the semi-IPN structures. The PLL hydrogel thus prepared
showed dynamic swelling/de-swelling behavior in response to pH change, and such a behavior was influenced by both the concentrations
of PLL and PEG-methacrylate. Drug release from this semi-IPN hydrogel was also investigated using a model protein drug, streptokinase.
Streptokinase release was found to be dependent on its ionic interaction with the PLL backbones as well as on the swelling
of the semi-IPN hydrogel. These results suggest that a PLL semi-IPN hydrogel could potentially be used as a drug delivery
platform to modulate drug release by pH-sensitivity and ionic interaction. 相似文献
100.
Trivedi CM Luo Y Yin Z Zhang M Zhu W Wang T Floss T Goettlicher M Noppinger PR Wurst W Ferrari VA Abrams CS Gruber PJ Epstein JA 《Nature medicine》2007,13(3):324-331
In the adult heart, a variety of stresses induce re-expression of a fetal gene program in association with myocyte hypertrophy and heart failure. Here we show that histone deacetylase-2 (Hdac2) regulates expression of many fetal cardiac isoforms. Hdac2 deficiency or chemical histone deacetylase (HDAC) inhibition prevented the re-expression of fetal genes and attenuated cardiac hypertrophy in hearts exposed to hypertrophic stimuli. Resistance to hypertrophy was associated with increased expression of the gene encoding inositol polyphosphate-5-phosphatase f (Inpp5f) resulting in constitutive activation of glycogen synthase kinase 3beta (Gsk3beta) via inactivation of thymoma viral proto-oncogene (Akt) and 3-phosphoinositide-dependent protein kinase-1 (Pdk1). In contrast, Hdac2 transgenic mice had augmented hypertrophy associated with inactivated Gsk3beta. Chemical inhibition of activated Gsk3beta allowed Hdac2-deficient adults to become sensitive to hypertrophic stimulation. These results suggest that Hdac2 is an important molecular target of HDAC inhibitors in the heart and that Hdac2 and Gsk3beta are components of a regulatory pathway providing an attractive therapeutic target for the treatment of cardiac hypertrophy and heart failure. 相似文献