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1.
Hector M. Alvarez Frank Mayer Dirk Fabritius A. Steinbüchel 《Archives of microbiology》1996,165(6):377-386
An oleaginous hydrocarbon-degrading Rhodococcus opacus strain (PD630) was isolated from a soil sample. The cells were able to grow on a variety of substrates and to produce large
amounts of three different types of intracellular inclusions during growth on alkanes, phenylalkanes, or non-hydrocarbon substrates.
Electron microscopy revealed large numbers of electron-transparent inclusions with a sphere-like structure. In addition, electron-dense
inclusions representing polyphosphate and electron-transparent inclusions with an elongated disc-shaped morphology occurred
in small amounts. The electron-transparent inclusions of alkane- or gluconate-grown cells were composed of neutral lipids
(98%, w/w), phospholipids (1.2%, w/w), and protein (0.8%, w/w). The major component of the cellular inclusions was triacylglycerols;
minor amounts of diacylglycerols and probably also some free fatty acids were also present. Free fatty acids and/or fatty
acids in acylglycerols in cells of R. opacus amounted up to 76 or 87% of the cellular dry weight in gluconate- or olive-oil-grown cells, respectively. The fatty acid composition
of the inclusions depended on the substrate used for cultivation. In cells cultivated on n-alkanes, the composition of the
fatty acids was related to the substrate, and intermediates of the β-oxidation pathway, such as hexadecanoic or pentadecanoic
acid, were among the acylglycerols. Hexadecanoic acid was also the major fatty acid (up 36% of total fatty acids) occurring
in the lipid inclusions of gluconate-grown cells. This indicated that strain PD630 utilized β-oxidation and de novo fatty
acid biosynthesis for the synthesis of storage lipids. Inclusions isolated from phenyldecane-grown cells contained mainly
the non-modified substrate and phenylalkanoic acids derived from the hydrocarbon oxidation, such as phenyldecanoic acid, phenyloctanoic
acid, and phenylhexanoic acid, and approximately 5% (w/w) of diacylglycerols. The lipid inclusions seemed to have definite
structures, probably with membranes at their surfaces, which allow them to maintain their shape, and with some associated
proteins, probably involved in the inclusion formation.
Received: 22 December 1995 / Accepted: 12 March 1996 相似文献
2.
Permanent contraception of dogs induced with intratesticular injection of a Zinc Gluconate-based solution 总被引:1,自引:0,他引:1
Oliveira EC Moura MR de Sá MJ Silva VA Kastelic JP Douglas RH Marques AP 《Theriogenology》2012,77(6):1056-1063
The objective was to evaluate the efficacy of a single intratesticular injection of a Zinc Gluconate-based solution to induce sterility in male dogs. Fifteen pubertal mongrel dogs (8 mo to 4 y old) were assigned to two groups; Control dogs (n = 5) received a single injection of an isotonic saline solution into each testis, whereas Treated dogs (n = 10), were given Testoblock, a proprietary zinc-gluconate (13.1 mg zinc/ml) solution in a physiological vehicle. The volume of saline or Testoblock injected varied from 0.2 to 1.0 ml/testis (based on testis width). Physical examination, testis width, hematology, clinical chemistry (hepatic and renal function), plasma testosterone concentration, semen characteristics, and libido, were assessed until castration (150 d after treatment). In Treated dogs, testis width increased (approximately 20%) relative to that in Control dogs, but subsequently was not significantly different from Controls (group × time interaction, P < 0.0001). For all dogs, values for hematology and clinical chemistry consistently remained within reference ranges. Although plasma testosterone concentrations decreased over time (P < 0.006), there was only a tendency for an effect of group (P < 0.09), and libido was not significantly affected. By 63 d after Testoblock treatment, eight Treated dogs were azoospermic, whereas the remaining two were oligozoospermic (<10 × 106 sperm/ml). We concluded that intratesticular injection of the Zinc Gluconate-based chemical sterilant Testoblock has considerable potential to induce permanent contraception in male dogs. 相似文献
3.
In the facultative methylotroph Arthrobacter P1 the enzyme transaldolase plays an important role in both the pentose phosphate pathway and in the ribulose monophosphate cycle of formaldehyde fixation.Among gluconate-negative mutants of Arthrobacter P1 strains occurred which also were unable to grow on xylose because they had lost the ability to synthesize transaldolase. Furthermore, this loss of transaldolase activity resulted in decreased growth rates on a number of other heterotrophic substrates. Contrary to expectation, these mutants still grew on methylamine and were even able to use gluconate as a carbon source at normal rates provided methylamine was supplied as a nitrogen source. Under these conditions high levels of transaldolase were observed.Partial purification of the transaldolases synthesized by gluconate-grown cells of wild type Arthrobacter P1 and methylamine-grown cells of one of these mutants, strain Art 98, revealed the presence of transaldolase isoenzymes. These enzymes displayed similar kinetics but were very different in heat sensitivity. Functionally these isoenzymes are apparently very similar but their synthesis is regulated differently. One of the enzymes is synthesized constitutively whereas the other is specifically induced during growth on C1 compounds. Strain Art 98 has lost the ability to synthesize the constitutive transaldolase. It is postulated that the C1-induced transaldolase serves to ensure a sufficiently high rate of regeneration of ribulose-5-phosphate during growth on C1 compounds.Abbreviations RuMP
ribulose monophosphate
- DEAE
diethylaminoethyl 相似文献
4.
Felice Aull 《生物化学与生物物理学报:生物膜》1979,554(2):538-540
Steady state Cl? flux across the Ehrlich mouse ascites cell membrane was studied when gluconate replaced Cl? in the external medium. Saturation behavior was observed; was 23.9 mM Cl? and V was 758 μmol · g?1 dry weight · h?1. The cells lost K+, Cl? and H2O, consistent with relative impermeability to gluconate, and the Cl? efflux rate coefficient was elevated. The results indicate that a major portion of Cl? exchange occurs as a membrane transport process and suggest that the process is sensitive to intracellular Cl? levels. 相似文献
5.
Al-Balool FY 《Comparative biochemistry and physiology. Toxicology & pharmacology : CBP》2005,141(1):1-7
The effects of mucosally added Escherichia coli heat stable enterotoxin (STa, 30 ng mL(-1)) on the basal short-circuit current (Isc in microA cm(-2)) across stripped and unstripped sheets of proximal, mid and distal colon were investigated. Samples were taken from fed, starved (4 days, water ad lib) and undernourished (50% of control food intake for 21 days) gerbils (Gerbillus cheesmani). The effect of neurotoxin tetrodotoxin (TTX 10 microM) and the effect of replacing chloride by gluconate or the effect of removing bicarbonate from bathing buffer on the maximum increase in Isc induced by E. coli heat stable enterotoxin STa were also investigated. The results showed that there is a segmental difference both in the basal and STa-induced Isc. Also, STa is more effective in the proximal than distal colon in the three feeding conditions. Undernourishment raised the STa-induced Isc in the three regions of the colon. In fed and starved gerbils part of STa-induced Isc in the proximal colon was chloride-dependent, while the other was bicarbonate-dependent; in the mid colon, the STa-induced Isc was bicarbonate-dependent only. In the three regions of the colon taken from undernourished gerbil, the STa-induced Isc was both chloride-and bicarbonate-dependent. The increase in STa-induced Isc as a results of undernourishment in proximal and mid colon was chloride-dependent, while in the distal colon, it was both chloride- and bicarbonate-dependent. 相似文献
6.
The glucose and fructose degradation pathways were analyzed in the halophilic archaeon Halococcus saccharolyticus by 13C-NMR labeling studies in growing cultures, comparative enzyme measurements and cell suspension experiments. H. saccharolyticus grown on complex media containing glucose or fructose specifically 13C-labeled at C1 and C3, formed acetate and small amounts of lactate. The 13C-labeling patterns, analyzed by 1H- and 13C-NMR, indicated that glucose was degraded via an Entner-Doudoroff (ED) type pathway (100%), whereas fructose was degraded almost completely via an Embden-Meyerhof (EM) type pathway (96%) and only to a small extent (4%) via an ED pathway. Glucose-grown and fructose-grown cells contained all the enzyme activities of the modified versions of the ED and EM pathways recently proposed for halophilic archaea. Glucose-grown cells showed increased activities of the ED enzymes gluconate dehydratase and 2-keto-3-deoxy-gluconate kinase, whereas fructose-grown cells contained higher activities of the key enzymes of a modified EM pathway, ketohexokinase and fructose-1-phosphate kinase. During growth of H. saccharolyticus on media containing both glucose and fructose, diauxic growth kinetics were observed. After complete consumption of glucose, fructose was degraded after a lag phase, in which fructose-1-phosphate kinase activity increased. Suspensions of glucose-grown cells consumed initially only glucose rather than fructose, those of fructose-grown cells degraded fructose rather than glucose. Upon longer incubation times, glucose- and fructose-grown cells also metabolized the alternate hexoses. The data indicate that, in the archaeon H. saccharolyticus, the isomeric hexoses glucose and fructose are degraded via inducible, functionally separated glycolytic pathways: glucose via a modified ED pathway, and fructose via a modified EM pathway.Abbreviations. KDG
2-Keto-3-deoxygluconate
- KDPG
2-Keto-3-deoxy-6-phosphogluconate
- FBP
Fructose-1,6-bisphosphate
- TIM
Triosephosphate isomerase
- GAP
Glyceraldehyde-3-phosphate
- PEP
Phosphoenolpyruvate
- PTS
Phosphotransferase
- 1-PFK
Fructose 1-phosphate kinase
An erratum to this article can be found at 相似文献
7.
Visceral Leishmaniasis is a macrophage associated disorder for the treatment of which antimony based drugs like SAG and SSG were the first choice in the recent past. The clinical value of antimony therapy is now declined against VL because increasing cases of Sodium Antimony Gluconate (SAG) resistance have reached outstanding proportion in Bihar, India. Within this context we looked into the protein sequences of ABC transporters of Leishmania spp associated with Visceral Leishmaniasis that are known to play a crucial role in the development of multidrug resistance (MDR). Our studies consisting of ClustalW, Phylogeny and TCOFFEE have pinpointed that ABC transporters have enormously diverged during the process of evolution even within the identical species strains resulting in insignificant homology and subdued conservation amongst the aminoacid residues. Moreover these amino acid residues remain susceptible to mutations in evolutionary era as indicated by high frequency of variations by the variability studies. Hence we predict that during the process of evolution a series of frequent mutations might have led to changes in the ABC transporters favorable to effluxing the drug thereby making the Leishmania species prone to resistance against the efficient first line drug SAG, used for combating VL. This selection has made them to survive efficiently in the adverse circumstances of antimony based antileishmanial therapy regime. 相似文献
8.
Joost A. Simons M. Joost Teixeira de Mattos Oense M. Neijssel 《Archives of microbiology》1993,159(4):386-391
The metabolism of gluconate by Klebsiella pneumoniae NCTC 418 was studied in continuous culture. Under all gluconate-excess conditions at low culture pH values (pH 4.5–5.5) the majority (70–90%) of the gluconate metabolized was converted to 2-oxogluconate via gluconate dehydrogenase (GADH), although specific 2-oxogluconate production rates under potassium-limited conditions were significantly lower than under other gluconate-excess conditions. At high culture pH values, metabolism shifted towards production of acetate. Levels of GADH were highest at low culture pH values and synthesis was stimulated by the presence of (high concentrations of) gluconate. An increase in activity of the tricarboxylic acid cycle was accompanied by a decrease in GADH activity in vivo and in vitro, suggesting that the GADH serves a role as an alternative energy-generating system. Anaerobic 2-oxogluconate production was found to be possible in the presence of nitrate as electron acceptor. Levels of gluconate kinase were highest when K. pneumoniae was grown under gluconate-limited conditions. Under carbon-excess conditions, levels of this enzyme correlated with the intracellular catabolic flux.Abbreviations GADH
gluconate dehydrogenase (EC 1.1.99.3)
- GAK
gluconate kinase (EC 2.7.1.12)
- GDH
glucose dehydrogenase (EC 1.1.99.17)
- PQQ
pyrroloquinoline quinone [2,7,9-tricarboxy-1-H-pyrrolo (2,3-f) quinoline-4,5-dione]
- TCA
trichloroacetic acid 相似文献
9.
Arun Kumar Haldar Kshudiram Naskar Nashreen S. Islam 《Experimental parasitology》2009,122(2):145-8062
We demonstrate that the combination of sub-optimal doses of Sodium Antimony Gluconate (SAG) and the diperoxovanadate compound K[VO(O2)2(H2O)], also designated as PV6, is highly effective in combating experimental infection of BALB/c mice with antimony resistant (SbR) Leishmania donovani (LD) as evident from the significant reduction in organ parasite burden where SAG is essentially ineffective. Interestingly, such treatment also allowed clonal expansion of antileishmanial T-cells coupled with robust surge of IFN-γ and concomitant decrease in IL-10 production. The splenocytes from the treated animals generated significantly higher amounts of IFN-γ inducible parasiticidal effector molecules like superoxide and nitric oxide as compared to the infected group. Our study indicates that the combination of sub-optimal doses of SAG and PV6 may be beneficial for the treatment of SAG resistant visceral leishmaniasis patients. 相似文献
10.
Jun-Ichi Nihashi Yasutaro Fujita 《Biochimica et Biophysica Acta (BBA)/General Subjects》1984,798(1):88-95
The regulation of induction of inositol dehydrogenase (EC 1.1.1.18) and gluconate kinase (EC 2.7.1.12) was studied in Bacillus subtilis. Inositol dehydrogenase is induced by myo-inositol and gluconate kinase is induced by D-gluconate. Both inductions were strongly repressed by rapidly metabolizable carbohydrates such as D-glucose, D-mannose, D-fructose and glycerol (D-glucose had the strongest repressive effect) but they were weakly repressed by slowly metabolizable carbohydrates. Although each carbohydrate exerted a stronger effect on the induction of inositol dehydrogenase than that of gluconate kinase, it showed a similar tendency with respect to the degree of repression of each induction. This catabolite repression could not be diminished by addition of cyclic AMP to medium. In addition, non-metabolizable D-glucose analogues had no or weak repressive effects. On the assumption that rapidly metabolizable carbohydrates might be metabolized to repress both inductions, it was investigated whether several mutants blocked in the Embden-Meyerhof pathway could produce metabolite(s) (repressor) to repress them. A phosphoglycerate kinase (EC 2.7.2.3) deficient mutant could produce the repressor from D-glucose, D-mannose, D-fructose and glycerol but other mutants could not produce it from carbohydrates unable to be metabolized ineach mutant. Thus, catabolite repression of both enzyme inductions seemed to be under similar regulation. The identification of the possible repressor of the induction of inositol dehydrogenase and gluconate kinase in vivo was discussed. 相似文献