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PubMed1998

Factors affecting biosynthesis by Xanthomonas albilineans of albicidin antibiotics and phytotoxins.

Albicidins are important factors in systemic pathogenesis by Xanthomonas albilineans, which causes the devastating leaf scald disease of sugar cane. They are also of substantial interest as antibiotics that selectively block prokaryote DNA replication. Albicidin biosynthesis is highly sensitive to medium composition. An optimized, chemically defined medium (SMG3) yielded 30-fold more albicidin from half the accumulated biomass, relative to sucrose peptone (SP) medium. Phosphate starvation stimulated albicidin production in SMG3 and SP media. Addition of other amino acids, ammonium ions or peptones to the defined medium increased the growth rate of X. albilineans XA3, but differentially inhibited albicidin biosynthesis. Knowledge of these factors indicates new approaches to understanding mechanisms of pathogenesis and resistance to sugar cane leaf scald disease, and to strain improvement for production of albicidin antibiotics.

Amino Acids↗
PubMed2005

Solid-state fermentation of cornmeal with the basidiomycete Ganoderma lucidum for degrading starch and upgrading nutritional value.

AIMS: The objective of this research was to study the ability of the basidiomycete Ganoderma lucidum to degrade starch and upgrade nutritional value of cornmeal during solid-state fermentation (SSF). METHODS AND RESULTS: On the basal medium that consisted of cornmeal and salt solution, alpha-amylase activity of G. lucidum reached its maximum value of 267 U g(-1) of culture on day 20 after inoculation. Prolongation of fermentation time from 10 to 25 days increased significantly the degradation rate of starch and ergosterol yield (a kind of physiologically active substances of G. lucidum, also as an indicator of mycelial biomass) (P < 0.01). Supplementation of glucose, sucrose or maltose to the basal medium also caused a significant increase in either the degradation rate of starch or the ergosterol yield as compared with control (P < 0.01). Among five kinds of nitrogen sources supplemented, yeast extract, casamino acid and peptone were more effective than (NH4)2SO4 and NH4NO3, and yeast extract gave the highest degradation rate of starch and ergosterol yield, followed by peptone. Through orthogonal experiments, the theoretical optimum culture medium for SSF of this fungus was the following: 100 g cornmeal, ground to 30-mesh powder, moistened with 67 ml of nutrient salt solution supplemented with 3 g yeast extract and 7.5 g glucose per litre. CONCLUSIONS: Under the optimum culture condition, the degradation rate of starch reached its maximum values of 70.4%; the starch content of the fermented product decreased from 64.5 to 25.3%, while the reducing sugar content increased from 4.2 to 20.6%. SSF also produced a significant increase (P < 0.01) from 11.0 to 16.5% in protein content. SIGNIFICANCE AND IMPACT OF THE STUDY: After SSF by G. lucidum, the digesting and absorbing ratio of cornmeal was strikingly increased and some active substances originated from G. lucidum remained in the fermented product. This implied that cornmeal could be processed into many kinds of special functional foods by SSF of G. lucidum.

Biomass↗
PubMed2006

A cost effective fermentative production of succinic acid from cane molasses and corn steep liquor by Escherichia coli.

AIM: Development and optimization of an efficient and inexpensive medium for succinic acid production by Escherichia coli under anaerobic conditions. METHODS AND RESULTS: Initially, 0.8 gl(-1) of succinic acid was produced in 60 h in 300-ml medium. On optimization, glucose and peptone were replaced by cane molasses and corn steep liquor. Three hundred ml of this medium was inoculated with 4% (v/v) of seed inoculum, incubated at 39 degrees C for 72 h, resulted in 7.1 gl(-1) of succinic acid in 36 h. Scale up in a 10-l fermentor under conditions of controlled pH and continuous CO2 supply in this medium resulted in 17 gl(-1) of succinic acid in 30 h. CONCLUSIONS: A ninefold increase in succinic acid production was obtained in 500-ml anaerobic bottles with optimized medium having cane molasses and corn steep liquor as against initial medium containing glucose and peptone. However, a subsequent scale up in a 10-l fermentor resulted in a 2.5-fold increase in succinic acid production as against optimized medium used in 500-ml anaerobic bottles. SIGNIFICANCE AND IMPACT OF THE STUDY: Succinic acid production was enhanced in medium consisting of inexpensive carbon and nitrogen sources in a shorter span of time.

Animals↗
PubMed1986

A note on the recovery of micro-organisms from an oil-in-water cream.

The isolation of micro-organisms from the oil-in-water Aqueous Cream BP, has been examined using a variety of solvent systems to disperse the cream prior to membrane filtration or direct inoculation. Pour-plate methods which utilize combinations of either peptone-water (containing 5% w/v polysorbate 80) or nutrient broth (containing 4% w/v Lubrol W) provided the most efficient recovery of Pseudomonas aeruginosa but still allowed less than 20% recovery. White spirit and isopropyl myristate allowed no recovery when used as dispersants. Recoveries of P. aeruginosa varied according to the source of the cream. A combination of 1% w/v polysorbate 80 in 0.1% w/v peptone-water and membrane filtration allowed 63.2% w/v and 67.0% w/v recoveries respectively of Aspergillus niger and Candida albicans from unpreserved aqueous cream, but gave unreproducible results for Escherichia coli and P. aeruginosa. Chlorocresol 0.1% w/v) did not meet the British Pharmacopoeial requirements for efficacy of antimicrobial preservatives when tested against C. albicans using membrane filtration to isolate the micro-organism.

Aspergillus niger↗
PubMed1996

Purification and catalytic properties of two manganese peroxidase isoenzymes from Pleurotus eryngii.

The ligninolytic basidiomycetes Pleurotus eryngii, Pleurotus ostreatus, Pleurotus pulmonarius and Pleurotus sajor-caju did not exhibit detectable levels of manganese peroxidase (MP) when grown in liquid media with ammonium tartrate as N source. However, after examination of cells grown on different organic N-based media, high MP activity was obtained in peptone medium, up to nearly 3 U/ml in cultures of P. eryngii. Moreover, Mn2+ supplementation was not used to produce MP, since all Mn2+ concentrations assayed (1-4000 microM) inhibited production of this enzyme in liquid medium. Two MP isoenzymes were purified to homogeneity from shaken or stationary cultures of P. eryngii grown in peptone medium. The purification process (which included chromatography on Biorad Q-cartridge, Sephacryl S-200 and Mono-Q) attained 56% activity yield with a purification factor of 25. The isoenzymes differed in pI (3.75 and 3.65), N-terminal sequence and some catalytic properties. They were in some aspects (e.g, molecular mass of 43 kDa) similar to Phanerochaete chrysosporium MP but exhibited some distinct characteristics, including Mn(2+)-independent peroxidase activities against 2,6-dimethoxyphenol and veratryl alcohol, and higher resistance to H2O2. Recent studies have shown that MP are ubiquitous enzymes in ligninolytic fungi, but the results obtained suggest that differences in catalytic properties probably exist between different Mn(2+)-oxidizing peroxidases produced by these fungi.

Amino Acid Sequence↗
PubMed1994

Influence of culture conditions on expression of antigens in Bordetella bronchiseptica.

Bordetella (B.) bronchiseptica isolates from the respiratory tract of rat and pig in their virulent phase-I and their spontaneously developed avirulent phase-III were investigated. The strains were cultured on Bordet-Gengou agar, on nutrition agar with 10% horse blood, and with 5% sheep blood, on yeast agar, on minimal nutrition agar (MM) and Simmon's citrate agar with glycerol, starch, and nicotinic acid. Antigenic modulation was induced by MgSO4 on Bordet-Gengou agar. The B. bronchiseptica strains were cultivated at 37 degrees C for 48 h. The influence of different MgSO4 concentrations after five passages (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100 mM/ml and low (20 degrees C) and high (42 degrees C) temperatures on antigenic modulation was investigated on Bordet-Gengou (B-G) agar. B. bronchiseptica colonies were characterized in relation to morphology, haemolysis, slide agglutination with B. bronchiseptica phase-I polyclonal antibodies, haemagglutination with horse and calf erythrocytes and polypeptide and LPS patterns in SDS-PAGE. Cultivation of B. bronchiseptica phase-I on B-G agar and ACMM agar at 37 degrees C for 48 h resulted in strong phase-I antigenic patterns, and, on peptone-rich media, in antigenic modulation. The morphology of B. bronchiseptica phase-I-strain colonies on peptone media was different from that of B-G and ACMM agar. The LPS pattern of both strains resembled that of phase-III strains. MgSO4 concentrations of 1 mM/ml (strain 1636 I) and 3 mM/ml (Ratte I) were able to induce LPS-pattern-like phase III.

Agglutination Tests↗
PubMed1997

Increased sensitivity of gastrin cells to gastric distension following antral denervation in the rat.

1. Secretion of the antral hormone gastrin is increased by protein in the gastric lumen and by nervous reflexes. We have examined the relative importance of luminal and neuronal mechanisms, by lesioning the antral innervation using benzalkonium chloride. 2. Benzalkonium chloride was applied to the serosa of the antrum in anaesthetized rats. In some animals, a stainless-steel cannula was also implanted in the corpus. Animals were allowed 10 days to recover. Plasma gastrin was measured by radioimmunoassay and mRNAs encoding gastrin, somatostatin and histidine decarboxylase were measured by Northern blot. 3. Antral denervation was associated with gastric retention after fasting, and elevated plasma gastrin (28.4 +/- 7 pM compared with 7.6 +/- 1.0 pM in controls). When fasted control or denervated rats were refed, plasma gastrin increased 3-fold in both cases. A gastrin-releasing peptide antagonist inhibited the post-prandial rise in plasma gastrin in control rats, but had no effect in antrally denervated rats. 4. In fasted, antrally denervated rats with a gastric fistula, basal gastric acid secretion was depressed 3-fold, and plasma gastrin concentrations were similar to controls. 5. Distension of the stomach with peptone via a barostat attached to the gastric cannula (5 cm H2O, 30 min), produced 3-fold increases in plasma gastrin in both control and denervated rats. However, distension with a non-nutrient solution at pH 6.0 had no effect in controls, but increased gastrin to a similar extent to peptone in denervated rats; distension with 50 mM HCl had no effect in either control or denervated rats. 6. Somatostatin and gastrin mRNA abundances in the antrum were depressed by about 35% by antral denervation, but somatostatin mRNA in the corpus was unchanged; GAPDH mRNA abundance was unaffected by antral denervation. 7. The data suggest that luminal nutrient releases gastrin in the rat, in vivo, via activation of antral neurons secreting gastrin-releasing peptide, and that the antral innervation normally inhibits G-cell responses to non-nutrient distension of the stomach. After antral denervation, gastric distension with a non-nutrient solution is an adequate stimulus for gastrin release.

Animals↗
PubMed2005

Improvement of xylanase production in solid-state fermentation by alkali tolerant Aspergillus versicolor MKU3.

AIMS: To optimize the media components for xylanase production by Aspergillus versicolor MKU3 in solid-state fermentation (SSF). METHODS AND RESULTS: Medium optimization was carried out using De Moe's fractional factorial design with seven components. Maximum production of xylanase 3249.9 U g(-1) was obtained in SSF with an optimized medium containing (g l(-1)): NaNO(3), 20; K(2)HPO(4), 20; MgSO(4), 10; FeSO(4), 0.001; KCl, 1; peptone, 10 and yeast extract, 10. Four components namely NaNO(3), MgSO(4), peptone and K(2)HPO(4) significantly increased the xylanase production by A. versicolor MKU3. CONCLUSIONS: Fractional factorial design was used to optimize the seven components in the fermentation medium for SSF. The optimized media increased xylanase production by 3.4-fold. SIGNIFICANCE AND IMPACT OF THE STUDY: Aspergillus versicolor MKU3 produced maximum xylanase after two steps of media optimization under alkaline condition. This medium will be significant value for xylanase production in SSF.

Alkalies↗
PubMedDate not supplied

YI-S, a casein-free medium for axenic cultivation of Entamoeba histolytica, related Entamoeba, Giardia intestinalis and Trichomonas vaginalis.

Pancreatic digests of casein are major ingredients of media used in the axenic cultivation of lumen-dwelling parasitic protozoa, especially Entamoeba, Giardia, and trichomonads. The digest used almost exclusively in the development of these media, Medo-Peptone (Trypticase BBL), has not been available since 1981. Moreover, none of dozens of similar type digests tested since then in our laboratory has proved equal to Medo-Peptone, and in the last two years it has become increasingly difficult to obtain new batches which will support even modest growth of Entamoeba histolytica. In response to this problem we have developed a casein-free medium, YI-S, consisting of a nutrient broth, vitamin mixture and serum. We recommend it as a replacement for the casein-dependent medium TYI-S-33, currently the most widely used for axenic culture of Entamoeba histolytica and other lumen-dwellers.

Animals↗
PubMed1998

A commensal symbiosis between Prevotella bivia and Peptostreptococcus anaerobius involves amino acids: potential significance to the pathogenesis of bacterial vaginosis.

In both batch and continuous culture, Peptostreptococcus anaerobius was able to grow in vaginal defined medium with Prevotella bivia, but not in pure culture. Growth of P. anaerobius was increased by 238% (P < 0.001) in peptone-supplemented vaginal defined medium conditioned by prior growth of P. bivia. Analysis of P. bivia culture supernatants showed a net accumulation of amino acids and subsequent growth of P. anaerobius in the conditioned supernatants resulted generally in amino acid utilization. Supplementation of peptone-supplemented vaginal defined medium with amino acids in concentrations similar to those available after prior growth with P. bivia were growth-stimulatory (246%, P=0.006) for P. anaerobius. Increased availability of amino acids by P. bivia is proposed as a mechanism to support the observed in vitro commensal symbiosis between P. bivia and P. anaerobius.

Amino Acids↗
PubMed1985

Effect of aerobic and anaerobic atmosphere on the detection of micro-organisms from blood cultures.

Blood from patients with suspected bacteraemia was simultaneously cultured in two Vacutainer blood culture bottles containing 45 ml of supplemented peptone broth (Becton Dickinson), five ml of blood in each bottle. The cultures were incubated at 37 degrees C for seven days. One of the bottles was vented and the other unvented. A total of 3958 blood culture sets were processed during the 20-month period of the study. Altogether 438 (11%) of the blood culture sets were positive. Of the 438 isolates, 317 (72%) were detected in both bottles, 61 (14%) in the vented bottle and 60 (14%) in the unvented bottle. A total of 60 (14%) isolates would not have been detected if only five ml of blood had been cultured. Only minor differences in the isolation rates of different bacterial and fungal species from the vented and unvented bottles were found. The results indicate that aerobic incubation of Vacutainer bottles with supplemented peptone broth is sufficient in routine diagnostic work.

Aerobiosis↗
PubMed1977

Comparative growth rates of selected anaerobic species in four commonly used broth media.

Generations times (g(t)) of selected anaerobic species were compared in four culture media commonly used for anaerobic bacteria to evaluate these media for growing inocula for anaerobic antibiotic susceptibility determinations. Twenty-two clinical isolates of Bacteroides fragilis, Fusobacterium spp., Clostridium perfringens, and Clostridium spp. were tested in Schaedler broth, supplemented Lombard-Dowell broth, supplemented thioglycolate broth, and supplemented peptone-yeast extract-glucose broth. Growth curves were performed in an anaerobic chamber; changes in cell density were followed by viable count procedures and, in some cases, turbidometric procedures. The clostridia did not appear to have significantly different g(t) values in different media. The g(t) values for the five clostridial species tested ranged from 18 to 45 min. The fusobacteria also showed no apparent differences in g(t) values in the four media; values ranged from 51 to 60 min. The two subspecies of B. fragilis tested showed no significant differences in g(t) values when compared with each other in the same media. The combined data, however, indicated that the growth rate in Schaedler broth was faster than in the other media (average g(t), 45.1 min), whereas the growth rate in peptone-yeast extract-glucose was slower (average g(t), 58.2 min). The growth rates in supplemented thioglycolate and supplemented Lombard-Dowell broth (average g(t), 53.6 min and average g(t), 51.0 min, respectively) were not significantly different.

Anaerobiosis↗
PubMed1978

Medium for the enumeration and isolation of bacteria from a Swine waste digester.

A habitat-simulating medium was developed for the enumeration and isolation of bacteria from a swine waste digester. A roll tube medium with growth factors for strict anaerobes from previously studied anaerobic ecosystems was used to evaluate the effects of deletion, addition, or level of digester fluid, digester fluid treated with acid or base, rumen fluid, fecal extract, anaerobic pit extract, tissue extract, carbohydrates, peptones, short-chain fatty acids, minerals, vitamins, N and P sources, reducing and solidifying agents, buffers, and gases on colony counts. Decreasing the agar concentration from 2.5 to 1.0% increased the counts twofold. Blending increased the counts 1.7-fold. With a medium (174) containing digester fluid, peptones, minerals, cysteine, sodium carbonate, and agar, colony counts were 60% of the microscopic count and improved yields 2.5 to 20 times those obtained with media previously used for digesters or developed for other anaerobic ecosystems. Colony counts continued to increase for up to 4 weeks of incubation. Medium 174 permits the enumeration of total, methanogenic, and, with deletion of reducing agent, aerotolerant bacteria. The results suggest that the predominant bacteria grow slowly and have requirements different from those of bacteria from other ecosystems.

Journal Article↗
PubMed1981

Bacterial culture preservation in frozen and dry-film methylcellulose.

Forty-seven of 61 bacterial cultures, including strains of Pseudomonas, Xanthomonas, Erwinia, Agrobacterium, Corynebacterium, Serratia, Klebsiella, and Escherichia, remained viable after storage in frozen methylcellulose or in dried methylcellulose for up to 38 months. Pathogenicity remained intact for those strains tested. Bacteria were grown on a solid medium and then removed and placed in 1.0% methylcellulose (cellulose methyl ether) to make a final suspension of 10 colony-forming units (CFU) per ml. For storage in dried form, the bacteria-methylcellulose suspension was placed in a petri dish and dried in a forced-air incubator. After 24 h of storage at 25 degrees C, viable populations of 10 CFU/mg (equivalent to 10 CFU/ml) were recovered. Populations of 10 to 10 CFU/mg were recovered after storage of up to 38 months. Similar results were obtained in frozen methylcellulose. Survival was greatly enhanced when the growth medium for the bacteria was potato dextrose peptone rather than nutrient agar, yeast dextrose calcium carbonate peptone, or King's medium B. Addition of 0.1 M MgSO(4) to the methylcellulose suspension and to the resuspending liquid also increased survival and recovery from storage for some strains. Methylcellulose storage should be a simple, inexpensive, and reliable method of maintaining cultures for short or long periods of time.

Journal Article↗
PubMed1981

Immunodiffusion method for detection of type A Clostridium botulinum.

A simple gel immunodiffusion agar procedure was developed for detecting toxigenic strains of Clostridium botulinum type A. The method consisted of overlaying colonies grown on thin-layer tryptone-peptone-glucose-yeast extract agar with gel diffusion agar containing desired levels of C. botulinum type A antitoxin. Concentric precipitin zones formed around colonies of C. botulinum type A. Strains of C. botulinum type A were detected by this procedure. However, C. botulinum type B reacted to a lesser degree with this system. No reaction was noted with types E, F, Langeland, F8G, Clostridium perfringens, or with strains of nontoxigenic Clostridium sporogenes. Thickness of the plating medium, incubation time and temperature, environmental growth conditions, and levels of both agar an antitoxin were important factors affecting the efficiency of the procedure, whereas the age of the culture (used as inoculum) was not critical. Thin agar medium (5 ml per plate [15 by 100 mm]) containing 1.5% agar gave consistent results, but more agar limited diffusion, and lower levels encouraged spreaders. The optimal concentration of antitoxin incorporated in to the gel diffusion agar overlay was 1.2 IU/ml gel diffusion agar. Rabbit type A antitoxin prepared with purer immunizing agent gave similar reactions. The addition of type A antitoxin in tryptone-peptone-glucose-yeast extract agar medium before inoculation with type A C. botulinum showed promising results.

Antitoxins↗
PubMed1982

Effect of oilseed cakes on alpha-amylase production by Bacillus licheniformis CUMC305.

The effects of oilseed cakes on extracellular thermostable alpha-amylase production by Bacillus licheniformis CUMC305 was investigated. Each oilseed cake was made of groundnut, mustard, sesame, linseed, coconut copra, madhuca, or cotton. alpha-Amylase production was considerably improved in all instances and varied with the oilseed cake concentration in basal medium containing peptone and beef extract. Maximum increases were effected by a low concentration (0.5 to 1.0%) of groundnut or coconut, a high concentration (3%) of linseed or mustard, and an Rintermediate concentration (2%) of cotton, madhuca, or sesame. The oilseed cakes made of groundnut or mustard could completely replace the conventional peptone-beef extract medium as the fermentation base for the production of alpha-amylase by B. licheniformis. The addition of corn steep liquor to cotton, linseed, sesame, or madhuca cake in the medium improved alpha-amylase production.

Amylases↗
PubMed1982

Survival of Campylobacter jejuni inoculated into ground beef.

Ground beef was inoculated with mixed cultures of Campylobacter jejuni, and the samples were subjected to various cooking and cold-storage temperatures. When samples were heated in an oven at either 190 or 218 degrees C, approximately 10(7) cells of C. jejuni per g were inactivated (less than 30 cells per g) in less than 10 min after the ground beef reached an internal temperature of 70 degrees C. When the samples were held at -15 degrees C over 14 days of storage, the numbers of C. jejuni declined by 3 log10. When inoculated samples were stored with an equal amount of Cary-Blair diluent at 4 degrees C, no changes in viability were observed over 14 days of storage. Twenty-five times as much C. jejuni was recovered from inoculated ground beef when either 10% glycerol or 10% dimethyl sulfoxide was added to an equal amount of ground beef before freezing as was recovered from peptone-diluted ground beef. Twice as much inoculated C. jejuni was recovered from ground beef plus Cary-Blair diluent as was recovered from ground beef plus peptone diluent.

Animals↗
PubMed1983

Hypochlorite injury of Clostridium botulinum spores alters germination responses.

Clostridium botulinum spores were sublethally damaged by exposure to 12 or 28 micrograms of available chlorine per ml for 2 min at 25 degrees C and pH 7.0. The damaging dose was 2.7 x 10(-6) to 3.1 x 10(-6) micrograms of available chlorine per spore. Damage was manifested by a consistent 1.6 to 2.4 log difference between the most probable number enumeration of spores (modified peptone colloid medium) and the colony count (modified peptone yeast extract glucose agar); this did not occur with control spores. Damaged spores could be enumerated by the colony count procedure. Germination responses were measured in several defined and nondefined media. Hypochlorite treatment altered the rate and extent of germination in some of the media. Calcium lactate (9 mM) permitted L-alanine (4.5 mM) germination of hypochlorite-treated spores in a medium containing 12 or 55 mM sodium bicarbonate, 0.8 mM sodium thiosulfate, and 100 mM Tris-hydrochloride (pH 7.0) buffer. Tryptose inhibited L-alanine germination of the spores. Treatments with hypochlorite and with hydrogen peroxide (7%, 25 degrees C, 2 min) caused similar enumeration and germination responses, indicating that the effect was due to a general oxidation phenomenon.

Alanine↗