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1.
Tokuya Harada Ken Fujimori Susumu Hirose Matsue Masada 《Bioscience, biotechnology, and biochemistry》2013,77(8):764-769
A defined medium was developed in which Alcaligenes faecalis var. myxogenes 10C3 mutant K produced a large quantity of β-glucan 10C3K. The medium contained 4% glucose together with 0.1% citrate, succinate or fumarate as the carbon source, 0.15% (NH4)2HPO4 as the nitrogen source and mineral salts. When NaNH4HPO4, KNO3 or urea was used at a concentration of 0.03% nitrogen as the sole nitrogen source, salts of organic acid were not needed in addition to glucose.In culture medium containing phosphate buffer (M/15, pH 6.5~8.0) large amounts of polysaccharide were formed and its yield from the 4% glucose added was about 50%. Thus, it was shown that polysaccharide production is enhanced greatly if a suitable pH for polysaccharide production is maintained during incubation. 相似文献
2.
Reis N Gonçalves CN Aguedo M Gomes N Teixeira JA Vicente AA 《Biotechnology letters》2006,28(7):485-490
A novel micro-bioreactor based on the oscillatory flow technology was applied to the scale-down of the biotechnological production
of γ-decalactone. A decrease up to 50% of the time required to obtain the maximum concentration of the compound was observed,
when compared with other scaled-down platforms (stirred tank bioreactor or shake flask). A three-fold increase in γ-decalactone
productivity was obtained by increasing oscillatory mixing intensity from Reo ~482 to Reo ~1447. This was presumably related to the effective contribution of the reactor geometry to enhanced mass transfer rates
between the two immiscible liquid phases involved in the process by increasing the interfacial area.
Revisions requested 11 October 2005; Revisions received 4 January 2006 相似文献
3.
Christian Schlichtherle 《Mycotoxin Research》1997,13(1):49-49
This paper describes the importance of fumonisins for human beings and animals and shows data for the occurence in food. Corn-based
food samples (n = 299) purchased in the area of munich were analyzed for fumonisin content using an enzyme immunoassay.
Fumonisins are mycotoxins produced byFusarium species, especially byFusarium moniliforme andFusarium proliferatum. Occurrence of fumonisins in corn and in cornbased foods and feeds has been reported from almost all over the world. In several
animal species different diseases are traced back to fumonisin toxicosis. Fumonisin levels of 5–10 ppm inhorse feed induce
“Equine Leucoencephalomalacia” and hepatic lesions. Hepatotoxic (10 150 ppm fumonisin in feed) and pneumotoxic (>150 ppm fumonisin
in feed) effects have been reported for swine. Cattle and poultry appear to be less susceptible to fumonisins. Fumonisin B1 Revels of 50 ppm in the diet of rats cause hepatotoxic and nephrotoxic effects, long time exposure results in hepatic cancer.
A possible role of fumonisins in the etiology of human esophageal cancer is under discussion, although no direct causal evidence
is known so far. The mode of action of the fumonisins is probably based on inhibition of sphingolipidbiosynthesis caused by
the blockade of the enzyme sphyngosine (sphinganine)-N-acyltrans-ferase. 相似文献
4.
Razzaghi-Abyaneh M Shams-Ghahfarokhi M Eslamifar A Schmidt OJ Gharebaghi R Karimian M Naseri A Sheikhi M 《Mycopathologia》2006,161(4):245-249
The effects of Akacid plus, a novel guanidine-based polymer first introduced as a biocidal and disinfectant agent were studied on Aspergillus parasiticus growth and its aflatoxin (AF) productivity. The fungus was cultured on yeast extract-sucrose (YES) broth in presence of various twofold serial dilutions of 25% Akacid plus (1.5-96 microL/50 mL medium) and then incubated in shaking condition with 150 rev./min at 28 degrees C for 96 h. Based on obtained results, Akacid plus was found to significantly inhibit both growth and aflatoxin B1 (AFB1) synthesis in very low concentrations in a dose-dependent manner. Fungal growth inhibition was determined in the range of 9.6-99.6% in mycelia exposed to the total concentration range of 1.5-48 microL. A final concentration of 96 microL was necessary to completely inhibit the growth of fungus. Under similar conditions, AFB1 synthesis was found to be strongly inhibited by 8.1-98.0% in presence of 1.5-24 microL Akacid plus with a maximum of 100% by 48 microL concentration. With respect to the unique physico-chemical properties of Akacid plus, its marked inhibitory effects on A. parasiticus growth and its AFB1 synthesis shown for the first time in this study make it a promising candidate for application in prevention programmes of AF contamination of susceptible crops. 相似文献
5.
Catharanthus roseus(L.) G. Don cells acidified Mura-shige-Skoogmedium rapidly. Upon transfer to fresh medium, the medium pH(initially5.3) dropped below 4 within 2 d. This acidificationwas reversed under hypoxic conditions. The cells induced a similaracidification in a simple medium consisting of CaCl2, KCl, andglucose: medium pH dropped below 4 within 6 h. The acidificationwas accompanied by an influx of K+ at a H+(efflux)/K+ ratioof ca 0.6 as well as by an expansion of endogenous organic acidpool, in which malic and citric acids were the major components.Anoxia reversed all these processes: the direction of both K+and H+ fluxes reversed with a H+/K+ ratio of 1.70. Anoxia induceda cytoplasmic acidification from pH 7.6 (aerobic) to 7.4 asmeasured by 31P-NMR, accompanied by a rapid, long-lasting lactateaccumulation at expense of malic and citric acids. Evidencesuggested that accumulation of lactic acid was not a cause ofcytoplasmic acidification under anoxia, but a result of pH regulationby the biochemical pH-stat [Davies (1973) Symp. Soc. Exp. Biol.27: 513]. The anoxic acidification of the cytoplasm was ascribedto the influx of H+ from the medium. (Received April 18, 1997; Accepted July 8, 1997) 相似文献
6.
The solubility of maltitol in pure water and industrial syrup was measured in a temperature range from 10 to 90 °C. Maltitol
is highly soluble in water, and this yields high viscosity values for the saturated aqueous solutions at different temperatures.
In addition, solubility of maltitol in ethanol/water mixtures was followed at 30, 35, 45, and 55 °C. Results show that maltitol
solubility is highly dependent on water content in the solvent mixture. Moreover, it increases monotonically with temperature.
The logarithm of viscosity changes linearly against the mole fraction of maltitol in the aqueous solutions up to saturation.
The saturated solutions showed a Newtonian behavior in a temperature range from 20 to 90 °C. Maltitol is also characterized
in supersaturated solutions by a narrow metastable zone, which slightly increases as temperature is raised. The density of
aqueous solutions of maltitol was measured as a function of molality up to saturation at 20 °C, and results show that density
can be correlated with concentration according to a linear relation. The obtained results were used to explain maltitol crystallization,
which exhibits a high nucleation rate and a slow growth leading to small size crystals. 相似文献
7.
Adriana da Silva Rezende Moreira Gisele Huf Maria Armanda Monteiro da Silva Vieira Paulo Albuquerque da Costa Fábio Aguiar Anna Grazia Marsico Leila de Souza Fonseca M?nica Ricks Martha Maria Oliveira Anne Detjen Paula Isono Fujiwara Stephen Bertel Squire Afranio Lineu Kritski 《PloS one》2015,10(6)
Background
The use of liquid medium (MGIT960) for tuberculosis (TB) diagnosis was recommended by WHO in 2007. However, there has been no evaluation of its effectiveness on clinically important outcomes.Methods and Findings
A pragmatic trial was carried out in a tertiary hospital and a secondary health care unit in Rio de Janeiro City, Brazil. Participants were 16 years or older, suspected of having TB. They were excluded if only cerebral spinal fluid or blood specimens were available for analysis. MGIT960 technique was compared with the Lowenstein-Jensen (LJ) method for laboratory diagnosis of active TB. Primary outcome was the proportion of patients who had their initial medical management changed within 2 months after randomisation. Secondary outcomes were: mean time for changing the procedure, patient satisfaction with the overall treatment and adverse events. Data were analysed by intention-to-treat. Between April 2008 and September 2011, 693 patients were enrolled (348 to MGIT, 345 to LJ). Smear and culture results were positive for 10% and 15.7% of participants, respectively. Patients in the MGIT arm had their initial medical management changed more frequently than those in the LJ group (10.1% MGIT vs 3.8% LJ, RR 2.67 95% CI 1.44–.96, p = 0.002, NNT 16, 95% CI 10–39). Mean time for changing the initial procedure was greater in LJ group at both sites: 20.0 and 29.6 days in MGIT group and 52.2 and 64.3 in LJ group (MD 33.5, 95% CI 30.6–36.4, p = 0.0001). No other important differences were observed.Conclusions
This study suggests that opting for the MGIT960 system for TB diagnosis provides a promising case management model for improving the quality of care and control of TB.Trial Registration
Controlled-Trials.com ISRCTN79888843 相似文献8.
AmyL, an extracellular α-amylase from Bacillus licheniformis, is resistant to extracellular proteases secreted by Bacillus subtilis during growth. Nevertheless, when AmyL is produced and secreted by B. subtilis, it is subject to considerable cell-associated proteolysis. Cell-wall-bound proteins CWBP52 and CWBP23 are the processed products of the B. subtilis wprA gene. Although no activity has been ascribed to CWBP23, CWBP52 exhibits serine protease activity. Using a strain encoding an inducible wprA gene, we show that a product of wprA, most likely CWBP52, is involved in the posttranslocational stability of AmyL. A construct in which wprA is not expressed exhibits an increased yield of α-amylase. The potential role of wprA in protein secretion is discussed, together with implications for the use of B. subtilis and related bacteria as hosts for the secretion of heterologous proteins.The cell envelope of the gram-positive bacterium Bacillus subtilis consists of a single (cytoplasmic) membrane surrounded by a relatively thick cell wall consisting of similar proportions of peptidoglycan and covalently attached anionic polymers. The absence of an outer membrane means that there is no equivalent of the membrane-enclosed periplasm found in gram-negative bacteria. However, by virtue of its thickness and high density of negative charge, the cell wall may perform some of the roles of the periplasm in gram-positive bacteria.The absence of an outer membrane in gram-positive bacteria also simplifies the secretion pathway, and, consequently, B. subtilis and its close relatives have the potential to secrete proteins directly into the growth medium, at concentrations in excess of 5 grams per liter (4). Despite its extensive use in the production of commercially important Bacillus enzymes (e.g., α-amylases and alkaline proteases), attempts to exploit B. subtilis for the production of heterologous proteins at high concentrations have proved disappointing (8). One reason for this failure is the production and release into the culture medium of several extracellular proteases (24, 28, 37). Although native Bacillus proteins are generally resistant to these proteases, heterologous proteins are often rapidly degraded in their presence. As a result, strains of B. subtilis that are multiply deficient in extracellular proteases have been developed (11, 37). The more developed of these strains have less than 1% of the proteolytic activity of the wild type (37). To date, efforts have concentrated mainly on the proteases which reside in a truly extracellular location, while those which remain cell associated have been largely overlooked.Although strains deficient in extracellular proteases have improved the productivity of B. subtilis for the production of heterologous proteins, they have only partially overcome problems of unexpectedly low yields. We and others have recently shown (22, 31) that significant amounts of secretory protein are degraded within minutes of being synthesized. This degradation is observed even for Bacillus proteins that are highly resistant to proteases released into the culture medium, suggesting that a component of this degradation is cell associated.Margot and Karamata recently reported the identification of a cell-wall-associated protease encoded by the wprA gene (21). The primary product of this gene is a 96-kDa polypeptide that is processed into two previously identified cell wall proteins, namely, CWBP52 and CWBP23. The processing of the WprA precursor during secretion accompanies the targeting of CWBP52 and CWBP23 to the cell wall and is analagous to the processing of another B. subtilis cell-wall-bound protein, namely, WapA (5). The amino acid sequence of CWBP52 shows a high degree of similarity with serine proteases of the subtilisin family, and phenylmethylsulfonile fluoride (PMSF)-sensitive protease activity was detected in proteins extracted from the cell wall of a wprA+ strain, but not one in which this gene had been insertionally inactivated (21). In the absence of homology to proteins in the databases, the N-terminal CWBP23 moiety was presumed to function as a chaperone-like propeptide that is proteolytically processed on the trans side of the membrane. In this paper, we report on a potential role of products of wprA in the integrity of secretory proteins during late stages in the secretion pathway. We also discuss the potential of wprA mutants to increase the productivity of B. subtilis for secretory proteins. 相似文献
9.
《Bioscience, biotechnology, and biochemistry》2013,77(6):1025-1027
We examined the effects of n-3 polyunsaturated fatty acid (PUFA), such as α-linolenic (α -LA), eicosapentaenoic (EPA), and docosahexaenoic acid (DHA) on immunoglobulin (Ig) production by spleen lymphocytes of Sprague-Dawley rats, n-3 polyunsaturated fatty acid (PUFA) strongly inhibited the production of IgA and IgM and that of IgG weakly at 100 μΜ. When the lymphocytes were treated with n-3 PUFA in the presence of other inhibitory biomaterials such as lectins, some PUFA attenuated their inhibitory effect on Ig production. In the presence of concanavalin A (ConA), all n-3 PUFA attenuated the inhibitory effect of ConA on the production of IgM or IgG but increased its inhibition of IgA synthesis. Thus, the interaction of n-3 polyunsaturated fatty acid and lectins in spleen interfere with each other or the expression of Ig production regulating activity. 相似文献
10.
2-Phenylethanol (2-PE) can be produced from l-phenylalanine (l-Phe) with the oxidation degradation of ethanol by active dry yeast. In this study, the catalysis effect of ethanol on biotransforming
l-Phe into 2-PE by yeast was evaluated and optimized. The results indicated that increasing ethanol concentration was beneficial
for enhancing 2-PE concentration but lowered the 2-PE productivity. Initial ethanol concentration above 25 g/l could strongly
inhibit the 2-PE production. To obtain 2-PE with desirable concentrations with an economical operation mode, three fed-batch
biotransformation operation methods using ethanol or/and glucose were carried out in a solid–liquid two-phase system. When
using ethanol alone with the initial concentration of 10 g/l, the total concentration and overall productivity of 2-PE were
7.6 g/l and 0.065 g l−1 h−1, respectively. Furthermore, an experiment with controlled glucose solely (higher than 2 g/l) was finished. In this case,
phenylacetaldehyde (PA) was detected along with ethanol accumulation, suggesting that reaction of PA → 2-PE in Ehrlich pathway
was inhibited. To further enhance 2-PE production by using glucose only, a novel operation strategy to simultaneously control
rates of glucose glycolysis and ethanol oxidative degradation with the aid of ISPR techniques was developed. With this strategy,
2-PE concentration and yield based on glucose consumption reached a higher level of 14.8 g/l and 0.12 g-PE/g-glucose, respectively,
and these are the highest values reported up to date with the fed-batch biotransformation operation mode. 相似文献
11.
At fixed concentration (0.5%), lactose and galactose acted as inducers while glucose and other tested carbon sugars showed
repression effects on β-galactosidase production in Enterobacter aerogenes strain. The expression of Vitreoscilla hemoglobin gene (vgb) in this bacterial strain managed to overcome the repression effects as well as improving the induction of β-galactosidase
formation by carbon sources. In parallel, the bacterial O2 consumption was increased correspondingly to the vgb induction of β-galactosidase synthesis. When Enterobacter aerogenes strains were grown at the incubation temperature 42°C, about 5-fold higher enzyme productivity was obtained than with a similar
incubation at 37°C. The bacterial growth expressed as biomass yield had a different optimum temperature and was not influenced
to the same extent by variations in the carbon sources. These data are discussed in terms of proposed enhancement in β-galactosidase
productivity by vgb expression as well as its significance to improve the technology of whey processing. 相似文献
12.
Y. L. Wong-Leung W. F. Fong W. L. Lam 《World journal of microbiology & biotechnology》1993,9(5):529-533
Extracts of both sugarcane and soybean wastes supported the growth of Monascus but sugarcane waste was superior for the production of -galactosidase. An aqueous extract prepared from 5% (w/v) soybean waste and 7% (w/v) sugarcane waste gave the best result and was superior to the standard peptone/glucose/yeast extract medium. Liquid-solid mixtures were slightly less effective. Enzyme production could be enhanced by adding raffinose. Enzymatic hydrolysis of p-nitrophenyl--D-galactoside was optimal at pH 4.5. Raffinose and stachyose were hydrolysed to sucrose and galactose. 相似文献
13.
Samuel R. Sherman 《The Western journal of medicine》1967,106(6):501-505
The subject of this Socio-Economic Report is of tremendous importance to the medical profession because physicians should be aware that future programs for the expansion of health care services will be based and, in fact, are being based upon information which this Report contains. The relationship between poverty and accessibility of health care services is therefore quite direct. So, too, will be the impact upon the profession and the organization of medical practice.The 1966 amendments to the Poverty Act are concerned with neighborhood health centers and a vast array of other programs which will touch every physician and every community which can be identified by the standards indicated in this Report as low income, poor, or near poor. For this reason the California Medical Association Committee on Welfare Medical Programs, among several others concerned with aspects of this problem, is trying to alert every county medical society of developments as well as of the responsibilities they should assume in working with the Office of Economic Opportunity and other community organizations in providing guidance and leadership in structuring programs compatible with the interests of the public and the health care professions.This Report on poverty presents a current and prospective view of the problems and issues to be faced. Unless physicians see the relationship and join in a community effort to aid in resolving an issue which underlies public policy, we shall be looking back five or ten years from now to point out that we failed to take advantage of opportunities to assist in the development of a rational system of medical care for low-income groups.Individual physicians, component medical societies on a grass-roots level and CMA as a state organization should all be concerned with and aware of the facts. 相似文献
14.
Hachiro Ozaki Koji Kubota Hiroshi Takahashi 《Bioscience, biotechnology, and biochemistry》2013,77(9):2503-2508
A drug-resistant mutant, No. 4–23–11, which had been derived from Pénicillium brevicompactum ATCC 16024, was cultured in a liquid medium for the production of mycophenolic acid (MPA) in the presence and absence of various adsorbents, that is, celites, zeolites, aluminas, talc, silica, charcoals, carbon blacks, natural graphite and carbonaceous mesophase spheres. In the absence of an adsorbent, MPA production (0.2 ~4.8 g/1) and the size of mycelium pellets (5~0.5mm) markedly depended on the concentration of spores inoculated (104~ 107/ml), whereas in the presence of one of these adsorbents, small pellets (smaller than 1 mm in diameter) were formed and the high production of MPA (4.5 — 5.4 g/1) was observed, independently of the spore concentration between approximately 104~ 107/ml. Microscopic observation of the pellets revealed that numerous particles of the adsorbents adhered to the surface of the hyphae. These results suggest that the adsorbents might interfere with the adhesion of hyphae to each other and thus retard the formation of large pellets. 相似文献
15.
Summary Two prey populations that share a common predator can interact indirectly by causing changes in the predator's foraging behaviour. Previous work suggests that adaptive choice of prey by the predator usually has two related consequences: (i) the predation rate on a particular prey species increases with the relative and/or absolute abundance of that prey; and (ii) increases in either prey population produce a short-term increase in the fitness of the other prey (short-term indirect mutualism between prey). This paper investigates how these two consequences are changed if the prey exhibit adaptive anti-predator behaviour. In this case, the predation rate on a particular prey often decreases as the prey's density increases. The predator then usually exhibits negative switching between prey. However, the presence of adaptive antipredator behaviour does not change the short-term mutualism between prey. In this case, as a prey becomes less common, it achieves a larger growth rate by reducing its anti-predator effort. These results imply that observations of the relationship between prey density and predation rate cannot be used to infer the nature of the behavioural indirect effect between prey that share a predator. 相似文献
16.
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18.
Hiroshi Sata Hajime Taniguchi Yoshiharu Maruyama 《Bioscience, biotechnology, and biochemistry》2013,77(12):3275-3280
Bacillus circulans F-2 requires a special carbon source or cultural conditions for amylase production. The α-glucosidase production of this bacterium was studied in various cultural conditions with measured glucose concèntrations. High amylase production was always accompanied by low α-glucosidase production and the absence of glucose in culture broth. Usually higher α-glucosidase production was observed in cultural conditions where little amylase was produced. In the presence of 1-deoxynojirimycin, an inhibitor of α-glucosidase activity, the bacterium produced significant amounts of amylase even in conditions giving high α-glucosidase production. It was concluded that the special requirement of this bacterium to produce amylase is effected by its high sensitivity to glucose repression and by the production of α-glucosidase which leads to the formation of glucose. Production of α-glucosidase was, like that of amylase, induced by maltooligosaccharides and repressed by glucose, but both its induction and repression are less sensitive to glucose than those of amylase. 相似文献
19.
A. Bartke N. Musto B.V. Caldwell H.R. Behrman 《Prostaglandins & other lipid mediators》1973,3(1):97-104
Administration of Phenylmethylsulfonylfluoride, an inhibitor of cholesterol esterase, to male mice caused an increase in the concentration of esterified cholesterol in the testis, a decrease in the weight of seminal vesicles and a decrease in the concentration of testosterone in peripheral plasma. It is suggested that hydrolysis of cholesterol esters present in the testis is required for normal production of androgenic steroids.Administration of prostaglandin F2α to male mice lowered plasma testosterone levels and raised the concentration of esterified cholesterol in the testes. Apparently testicular steroidogenesis was inhibited. 相似文献
20.
Effects of Interaction Between Cadmium and Plumbum on Phytochelatins and Glutathione Production in Wheat (Triticum aestivum L.) 总被引:2,自引:0,他引:2
QinSUN Xiao-RongWANG Shi-MingDING Xin-FangYUAN 《植物学报(英文版)》2005,47(4):435-442
Phytochelatins (PCs) may function as a potential biomarker for metal toxicity. However, less attention has been paid to the effects of metal interactions on the production of PCs and glutathione (GSH), the most prominent cellular thiol. In the present study, the effects of interactions between cadmium (Cd) and plumbum (Pb) on the production of PCs and GSH were monitored over a period of 14 d in wheat (Triticum aestivum L.) tissues. The results showed that combination of Cd and Pb led to synergistic growth inhibition in wheat. Exposure to Cd or Pb increased levels of PCs in a concentration-, tissue-, and time-dependent manner. Cadmium was more effective that Pb in increasing PCs production. Compared with the effects of Cd or Pb alone on the production of PCs, the combination of Cd and Pb acted synergistically, resulting in an enhanced production of PCs. Cadmium also stimulated GSH production in a concentration-, tissue-, and time-dependent manner. However, Pb had no obvious effects on GSH levels. The combination of Pb and Cd antagonized GSH production over the course of the growth period. The results of the present study suggest that metal interactions should be considered in the application of PCs and GSH as potential biomarkers for the evaluation of metal toxicity. 相似文献