Effect of carbohydrates on the growth ofRhizoctonia solani Kühn

The growth OfRhizoctonia solani in different carbohydrates was studied. The rate of growth of the fungus was traced by taking the dry weights of mycelia obtained from the carbohydrate medium at regular intervals and shifts in the pH were recorded. Different carbohydrate sources had different effects on the growth of the organism. The exoenzymes from the organism were capable of cleaving carbohydrates irrespective of whether the fungus grew in them or not.     

Growth characteristics on cellobiose of three different anaerobic fungi isolated from the ovine rumen.

Three morphologically different anaerobic fungi, a Neocallimastix sp. strain (LM-1), a Piromonas sp. strain (SM-1), and a Sphaeromonas sp. strain (NM-1), were isolated from the rumens of sheep. Growth studies were conducted with each isolate in batch cultures by using an anaerobic semidefined medium that lacked ruminal fluid and contained 0.5% cellobiose. Cultures were incubated for periods of up to 10 days, and fungal growth was assessed at regular intervals by dry weight measurements. Samples of fungal biomass were also analyzed for cell-associated protein and, after acid hydrolysis, for chitin as hexosamine. The isolates produced similar yields of dry weight and contained similar amounts of protein. However, strain LM-1 grew at a higher rate and contained less than half the level of chitin compared with the other two isolates. There were high positive correlations between chitin and protein for all three fungi, but comparisons of these parameters with dry weights were affected by the presence of variable amounts of storage carbohydrate. The amount of storage carbohydrate reached maximum levels in strain LM-1 during mid-growth phase and then quickly declined thereafter. When dry weight yields for strain LM-1 were adjusted for changes in storage carbohydrate, high positive correlations were obtained between dry weight and protein or chitin. The storage carbohydrate was probably an alpha-1,4-glucan with alpha-1,6 branches.     

The effect of growth medium on B. anthracis Sterne spore carbohydrate content

The expressed characteristics of biothreat agents may be impacted by variations in the culture environment, including growth medium formulation. The carbohydrate composition of B. anthracis spores has been well studied, particularly for the exosporium, which is the outermost spore structure. The carbohydrate composition of the exosporium has been demonstrated to be distinct from the vegetative form containing unique monosaccharides. We have investigated the carbohydrate composition of B. anthracis Sterne spores produced using four different medium types formulated with different sources of medium components. The amount of rhamnose, 3-O-methyl rhamnose and galactosamine was found to vary significantly between spores cultured using different medium formulations. The relative abundance of these monosaccharides compared to other monosaccharides such as mannosamine was also found to vary with medium type. Specific medium components were also found to impact the carbohydrate profile. Xylose has not been previously described in B. anthracis spores but was detected at low levels in two media. This may represent residual material from the brewery yeast extract used to formulate these two media. These results illustrate the utility of this method to capture the impact of growth medium on carbohydrate variation in spores. Detecting carbohydrate profiles in B. anthracis evidentiary material may provide useful forensic information on the growth medium used for sporulation.     

Growth characteristics on cellobiose of three different anaerobic fungi isolated from the ovine rumen

Three morphologically different anaerobic fungi, a Neocallimastix sp. strain (LM-1), a Piromonas sp. strain (SM-1), and a Sphaeromonas sp. strain (NM-1), were isolated from the rumens of sheep. Growth studies were conducted with each isolate in batch cultures by using an anaerobic semidefined medium that lacked ruminal fluid and contained 0.5% cellobiose. Cultures were incubated for periods of up to 10 days, and fungal growth was assessed at regular intervals by dry weight measurements. Samples of fungal biomass were also analyzed for cell-associated protein and, after acid hydrolysis, for chitin as hexosamine. The isolates produced similar yields of dry weight and contained similar amounts of protein. However, strain LM-1 grew at a higher rate and contained less than half the level of chitin compared with the other two isolates. There were high positive correlations between chitin and protein for all three fungi, but comparisons of these parameters with dry weights were affected by the presence of variable amounts of storage carbohydrate. The amount of storage carbohydrate reached maximum levels in strain LM-1 during mid-growth phase and then quickly declined thereafter. When dry weight yields for strain LM-1 were adjusted for changes in storage carbohydrate, high positive correlations were obtained between dry weight and protein or chitin. The storage carbohydrate was probably an alpha-1,4-glucan with alpha-1,6 branches.     

Diurnal Changes in Maize Leaf Photosynthesis : III. Leaf Elongation Rate in Relation to Carbohydrates and Activities of Sucrose Metabolizing Enzymes in Elongating Leaf Tissue

Maize (Zea mays L. cv. Pioneer 3184) leaf elongation rate was measured diurnally and was related to diurnal changes in the activities of sucrose metabolizing enzymes and carbohydrate content in the elongating portion of the leaf. The rate of leaf elongation was greatest at midday (1300 hours) and was coincident with the maximum assimilate export rate from the distal portion of the leaf. Leaf elongation during the light period accounted for 70% of the total observed increase in leaf length per 24 hour period. Pronounced diurnal fluctuations were observed in the activities of acid and neutral invertase and sucrose phosphate synthase. Maximum activities of sucrose phosphate synthase and acid invertase were observed at 0900 hours, after which activity declined rapidly. The activity of sucrose phosphate synthase was substantially lower than that observed in maize leaf source tissue. Neutral invertase activity was greatest at midday (1200 hours) and was correlated positively with diurnal changes in leaf elongation rate. There was no significant change in the activity of sucrose synthase over the light/dark cycle. Sucrose accumulation rate increased during a period when leaf elongation rate was maximal and beginning to decline. Maximum sucrose concentration was observed at 1500 hours, when the activities of sucrose metabolizing enzymes were low. At no time was there a significant accumulation of hexose sugars. The rate of starch accumulation increased after the maximum sucrose concentration was observed, continuing until the end of the light period. There was no delay in the onset of starch mobilization at the beginning of the dark period, and essentially all of the starch was depleted by the end of the night. Mobilization of starch in the elongating tissue at night could account for a significant proportion of the calculated increase in the tissue dry weight due to growth. Collectively, the results suggested that leaf growth may be controlled by the activities of certain sucrose metabolizing enzymes and may be coordinated with assimilate export from the distal, source portion of the leaf. Results are discussed with reference to diurnal photoassimilation and export in the distal, source portion of the leaf.     

Growth limitation and cell production bySaccharomycopsis fibuligera on a starch medium

Summary Batch cultures ofSaccharomycopsis fibuligera on a starch medium showed that the aerobic growth of the yeast was limited by total carbohydrate contents of the substrate, no inhibitory effect of metabolites being noticeable. Cell numbers increased earlier than dry weights of the biomass during adaptation to the medium. A significative increase in cell sizes accompanied active carbohydrate metabolism.     

Growth,photosynthesis, nitrogen fixation and carbohydrate production by a unicellular cyanobacterium,Synechococcus sp. (Cyanophyta)

A polymer-producing strain of unicellular cyanobacteria, Synechococcus sp., was isolated from a coastal lagoon in Florida. This strain, designated BG0011, excreted a highly viscous polysaccharide. Maximum observed growth rates for BG0011 were 2.5 div. day^-2. BG0011 also exhibited nitrogen fixation (nitrogenase) activity under aerobic conditions and grew at near maximum rates in medium lacking reduced nitrogen. Growth and carbohydrate production were enhanced by carbon dioxide enrichment. Rheological study of the extracellular polysaccharide revealed a viscosity versus shear rate curve similar in shape to that of xanthan gum. Maximum observed rate of carbohydrate production was 1 g dry weight liter^-1 month^-1.     

An alternative approach to the fermentation of sweet sorghum juice into biopolymer of poly-β-hydroxyalkanoates (PHAs) by newly isolated, Bacillus aryabhattai PKV01

This work revealed for the first time the possible use of a newly isolated Bacillus aryabhattai PKV01 for poly-β-hydroxyalkanoates (PHAs) production from fermentative sweet sorghum juice. Its growth and PHA production were investigated under different pH and nitrogen sources. Medium composition was optimized using statistical tools. The highest biomass and PHA content were reached at pH 6.5 with the use of urea. Plackett-Burman design was then applied to test the relative importance of medium components and process variables on cell growth and PHA production. Cell growth and PHAs production were affected by total sugar and urea and were subjected to optimize the sorghum juice medium using response surface methodology (RSM) via central composite design (CCD). The predicted optimal culture composition was achieved. Maximum dry cell weight and PHAs were obtained using a flask and almost double the amount was achieved using a bioreactor. After PHA recovery, the structure and thermal properties were characterised and revealed to be similar to the standard of poly-β-hydroxybutyrate (PHB).     

Utilization of Chondroitin Sulfate by Bacteroides thetaiotaomicron Growing in Carbohydrate-Limited Continuous Culture

When Bacteroides thetaiotaomicron, an obligate anaerobe from the human colonic flora, was grown in continuous culture with the mucopolysaccharide chondroitin sulfate as the limiting source of carbohydrate, growth yields ranged from 48 g of cell dry weight per mol of equivalent monosaccharide at a growth rate of 3.5 h per generation to 32 g per mol at a growth rate of 24 h per generation. The theoretical maximum growth yield (61 g of cell dry weight per mol of equivalent monosaccharide) was comparable to that of 54 g per mol, which was obtained previously when glucuronic acid, a component of chondroitin sulfate, was the limiting carbohydrate (S. F. Kotarski and A. A. Salyers, J. Bacteriol. 146:853-860, 1981). However, the maintenance coefficient was three times higher when chondroitin sulfate was the substrate than when glucuronic acid was the substrate. The specific activity of chondroitin lyase (EC 4.2.2.4), an enzyme which cleaves chondroitin sulfate into disaccharides, declined by nearly 50% as growth rates decreased from 3.5 to 24 h per generation. By contrast, the specific activities of several glycolytic enzymes and disaccharidases remained constant over this range of growth rates. Although chondroitin sulfate was growth limiting, some carbohydrate was detectable in the extracellular fluid at all growth rates. At rapid growth rates (1 to 2 h per generation), this residual carbohydrate included fragments of chondroitin sulfate having a wide range of molecular weights. At slower growth rates (2 to 24 h per generation), the residual carbohydrate consisted mainly of a small fragment which migrated on paper chromatograms more slowly than the disaccharides produced by chondroitin lyase but faster than a tetrasaccharide. This small fragment may represent the reducing end of the chondroitin sulfate molecule.     

Nitrogen Reserve Mobilization during Regrowth of Medicago sativa L. (Relationships between Availability and Regrowth Yield)

An experiment was designed to study the role of N and C reserves on regrowth of the shoots following defoliation of forage species. Starch and N accumulation in root and crown tissue of nonnodulated Medicago sativa L. were modified during regrowth by applying different levels of N and different cutting heights. Plants were obtained with similar crown and root dry weights, but having either low starch and high tissue N or high starch and low tissue N. The plants were then submitted to a second defoliation and supplied with optimal N nutrition, and N flow from reserve was quantified using pulse-chase 15N labeling. Maximum yields following the second regrowth were obtained from those plants having a high tissue N, despite their low level of nonstructural carbohydrate. When N in the roots and crown exceeded 5 mg N plant-1 at the beginning of regrowth, about 68% was translocated to regrowing shoots. Highly significant correlations were also found between the amounts of N available in roots and crown at the beginning of regrowth and (a) the amount of N that was mobilized to new tissues, (b) the amount of N taken up during the regrowth period, and (c) the final shoot yield after 24 d of regrowth. No similar correlations were found for plants that varied in their initial starch content of roots and crown. It is suggested that N reserves were used mainly during the first 10 d after defoliation, and that the resulting aerial growth during this period should be sufficient to restore N2 fixation and/or N uptake to levels equal to those prior to defoliation. These data emphasize (a) the importance of root N reserves in initiating and sustaining new shoot growth, and (b) the need for a re-evaluation of the contribution of C reserves to shoot regrowth.     

Evaluation of antitumour activity of tea carbohydrate polymers in hepatocellular carcinoma animals

Box-Behnken design criterion was applied to identify the significant effects of various extraction parameters such as temperature, time, and solvent-solid ratio on extraction of tea carbohydrate. Among the three variables tested extraction temperature, and solvent-solid ratio were found to have significant effect on tea carbohydrate extraction. The most suitable condition for extraction of tea carbohydrate was found to be a single step extraction at extraction temperature 90°C, extraction time 30 min, and solvent-solid ratio 5:1. At these optimum extraction parameters, the maximum yield of tea carbohydrate obtained experimentally was found to be very close to its predicted value of 3.47% dry weight of root. Then, we have studied the influence of tea carbohydrate on biochemical parameters in hepatocellular carcinoma (HCC) animals. Hepatocellular carcinoma was induced by the injection of 1×10(5) H22 hepatocarcinoma cells into right hind thigh muscle in experimental animals. Tea carbohydrate could inhibit tumour growth and decrease microvessel density in tumour tissue. The altered amount of serum white blood cells (WBC), Interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) in HCC animals were dose-dependently increased, whereas activities of serum alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) were dose-dependently decreased in the drug treated animals. In addition, tea carbohydrate administration could decrease expression of vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) in H22 tumor tissue. It can be concluded that tea carbohydrate displayed strong antitumour activity in animals.     

Mannitol Production by Pyrenochaeta terrestris

Pyrenochaeta terrestris (Hansen) Gorenz, J. C. Walker and Larson produces D-mannitol in the mycelium but not in the cutture filtrates when grown in a sucrose salts liquid medium. In the present study, P. terrestris was grown in stilt culture on a synthetic salts medium containing 30 g of sucrose per liter. After inoculation with a myceliat suspension, the mycelial mats were harvested and the dry weight and the amount of mannitol were determined. Maximum mycelial mat production occurred at 15 days after inoculation while the amount of mannitol was greatest at about 7 days after inoculation. The percentage of mannitot on a dry weight basis was maximal (20–25 per cent) within a few days after inoculation and decreased rapidly to 3–4 per cent at the time mycelial mat production was greatest. The same percentage of mannitot was produced when the fungus was grown in shake culture or when the sucrose was replaced by equivalent amounts of D-fructose, D-glucose, D-mannose, maltose, trehalose, and raffinose. Increasing the amount of sucrose or decreasing the amount of sodium nitrate increased the amount of mycelium produced but the percentage of mannitol in the mycelium remained about the same. Mannitot was reutilized when mycelial mats were transferred to a mineral medium without a carbon source. It was concluded that mannitot probably serves as a reserve carbohydrate in P. terrestris.     

Carbohydrate metabolism in Nerine sarniensis bulbs developing in liquid culture

Anatomical and physiological changes accompanying enhanced Nerine sarniensis cv. Salmon Supreme bulb growth in vitro were examined. Small bulbs, 2–3 mm in diameter, grown in vitro on a semi-solid medium were subcultured to liquid medium with elevated levels of sucrose (Suc) and inorganic phosphate. Bulbs' fresh and dry weights, carbohydrate contents and the activities of enzymes related to carbohydrate metabolism were determined at different stages of bulb development. Starch was the dominant storage carbohydrate in these bulbs, and the leaf bases parenchyma cells were the principal storage tissue. During the first month of bulb growth, only small changes in starch content were detected. However, an increase in starch level was observed at later stages of development. The activity of ADP-glucose pyrophosphorylase (EC 2.7.7.27), a key enzyme of starch synthesis, increased just before the increase in starch accumulation. Sucrose was the dominant soluble sugar in the bulbs, only traces of glucose and fructose were detected. The activity of alkaline invertase (INV, EC 3.2.1.26) was higher than that of acid INV during the growth period. Sucrose synthase (EC 2.4.1.13) exhibited the highest Suc-degrading activity during bulb growth. Suc was hydrolyzed in the medium by the cell wall bound acid INV during the growing period. The results are discussed in relation to enhanced nerine bulb growth and development in vitro.     

Studies on the prolonged storage of Metarhizium anisopliae conidia: effect of temperature and relative humidity on conidial viability and virulence against mosquitoes

The shell lengths, dried shell weights, soft tissue wet weights, and soft tissue dry weights were ascertained for noninfected Ilyanassa obsoleta and for the same snail species naturally infected with the following digeneans: Himasthla quissetensis, Zoogonus lasius, Cercaria dipterocerca, Lepocreadium setiferoides, Microphalloides nassicola, Stephanostomum tenue, and Microbilharzia variglandis. Analyses of the data obtained indicate that infection with all of the trematodes listed above causes neither enhanced growth of soft tissues nor accelerated lengthening of the shell. However, snails infected with sporocysts of Z. lasius have significantly heavier shells than do noninfected snails. These data suggest that infection with Z. lasius may have caused enhanced growth in the form of increased calcium deposition in the shell of I. obsoleta, possibly as a result of parasitic castration. In addition, the mean dry weight of the soft tissues of snails infected with M. variglandis, when normalized for shell length, is significantly lower than that of noninfected snails, possibly as a result of parasite-induced pathology. Finally, comparisons among infected snails indicate a trend toward increased soft tissue dry weight in snails infected with L. setiferoides, although the mean dry weight of these snails does not differ significantly from the mean dry weight of noninfected snails.     

Studies on the biosorption of uranium by a thermotolerant, ethanol-producing strain of Kluyveromyces marxianus

The ability of residual biomass from the thermotolerant ethanol-producing yeast strain Kluyveromyces marxianus IMB3 to function as a biosorbent for uranium has been examined. It was found that the biomass had an observed maximum biosorption capacity of 120?mg U/g dry weight of biomass. The calculated value for the biosorption maximum, obtained by fitting the data to the Langmuir model was found to be 130?mg U/g dry weight biomass. Maximum biosorption capacities were examined at a number of temperatures and both the observed and calculated values obtained for those capacities increased with increasing temperature. Decreasing the pH of the biosorbate solution resulted in a decrease in uptake capacity. When biosorption reactions were carried out using sea-water as the diluent it was found that the maximum biosorption capacity of the biomass increased significantly. Using transmission electron microscopy, uranium crystals were shown to be concentrated on the outer surface of the cell wall, although uranium deposition was also observed in the interior of the cell.     

Effects of nitrogen on growth and carbohydrate formation in Porphyridium cruentum

The microalga Porphyridium cruentum (Rhodophyta) has several industrial and pharmaceutical uses, especially for its polysaccharide production. This study aimed to investigate the influence of nitrogen levels as reflected by altered N:P ratios on the production and content of biomass and carbohydrate. N:P molar ratios were altered in batch cultures to range from 1.6 to 50 using the Redfield ratio of 1:16 as reference. Algal growth (estimated as final cell number, biomass concentration and maximum specific growth rate) was negatively affected at low N:P ratios. The optimal N:P ratio for growth was identified at 35–50, with specific growth rates of 0.19 day^?1 and maximum cell concentrations of 59·10⁸ cells L^?1 and 1.2 g dry weight of biomass L^?1. In addition, variation in cell size was seen. Cells with larger diameters were at higher N:P ratios and smaller cells at lower ratios. The cellular carbohydrate content increased under reduced nitrogen availability. However, because accumulation was moderate at the lowest N:P ratio, 0.4 g per g dry weight biomass compared to 0.24 at the Redfield ratio of 16:1, conditions for increased total carbohydrate formation were identified at the N:P ratios optimal for growth. Additionally, carbohydrates were largely accumulated in late exponential to stationary phase.     

Influence of manganese deficiency and toxicity on isoprenoid syntheses

Twenty-eight day old wheat (Triticum aestivum L. cv Stacy) response to varying Mn concentration (10.1-10,000 micromolar) in nutrient solution was measured. Manganese concentrations in the most recently matured leaves (blade 1) were 0.21 to 19.03 mmol Mn per kilogram dry weight, respectively. Fresh and dry weights increased to a maximum at the 5 micromolar Mn nutritional level (0.37 millimole Mn per kilogram dry weight) and were decreased at Mn above and below this concentration. Blade 1 chloroplast pigment concentrations increased up to the 20 micromolar Mn nutritional level (1.98 millimole Mn per kilogram dry weight) and decreased at higher Mn concentrations. Thylakoid Mn content was above 1 mole Mn/100 mole chloroplast at Mn nutrition levels which resulted in greatly decreased plant growth. Total phytoene biosynthesis was decreased by Mn deficiency and toxicity. In vitro ent- kaurene synthesis was greatly influenced by Mn concentration with a maximal biosynthesis at 1 micromolar Mn and decreases at Mn levels above and below this concentration. In vivo blade 1 gibberellic acid equivalent concentrations were maximal at 20 parts per million Mn nutrition solution levels (1.98 millimole Mn per kilogram dry weight) and decreased at Mn tissue concentrations above and below this value; additionally, gibberellic acid concentrations were reciprocal to extracted C₂₀ alcohol concentrations. Mn influence on gibberellin and chloroplast pigment biosyntheses exactly matched the measured changes in growth.     

Biochemical aspects of oögenesis in Drosophila melanogaster

The growth of ovaries of a wild type strain of Drosophila melanogaster has been studied from eclosion to 7 days later. Wet weight, protein, DNA, RNA, and carbohydrate have been determined at successive intervals. All experiments were performed on flies grown axenically on a killed yeast medium. The results indicate that wet weight increases rapidly from day 1 to day 4 and reaches a maximum at day 6. This increase is associated with the appearance of vitellogenic and post-vitellogenic stages of oögenesis. The increase in protein and RNA generally follows the wet weight curve and remains more or less constant after reaching a maximum at day 6. The DNA content reaches a maximum at day 3 and falls rapidly thereafter. The carbohydrate content increases slowly, reaching a maximum at day 7. The data are compared with available evidence from other strains and genotypes of D. melanogaster.     

Alkaloid production in Vernonia cinerea: Callus, cell suspension and root cultures

Fast-growing callus, cell suspension and root cultures of Vernonia cinerea, a medicinal plant, were analyzed for the presence of alkaloids. Callus and root cultures were established from young leaf explants in Murashige and Skoog (MS) basal media supplemented with combinations of auxins and cytokinins, whereas cell suspension cultures were established from callus cultures. Maximum biomass of callus, cell suspension and root cultures were obtained in the medium supplemented with 1 mg/L alpha-naphthaleneacetic acid (NAA) and 5 mg/L benzylaminopurine (BA), 1.0 mg/L NAA and 0.1 mg/L BA and 1.5 mg/L NAA, respectively. The 5-week-old callus cultures resulted in maximum biomass and alkaloid contents (750 microg/g). Cell suspension growth and alkaloid contents were maximal in 20-day-old cultures and alkaloid contents were 1.15 mg/g. A 0.2-g sample of root tissue regenerated in semi-solid medium upon transfer to liquid MS medium containing 1.5 mg/L NAA regenerated a maximum increase in biomass of 6.3-fold over a period of 5 weeks. The highest root growth and alkaloid contents of 2 mg/g dry weight were obtained in 5-week-old cultures. Maximum alkaloid contents were obtained in root cultures in vitro compared to all others including the alkaloid content of in vivo obtained with aerial parts and roots (800 microg/g and 1.2 mg/g dry weight, respectively) of V. cinerea.     

Long-term in vitro culture of wheat grains

Wheat (Triticum aestivum, Triticum durum) grains were excised immediately following fertilization and cultured until maturity. A rachis fragment attached to the grain was required to ensure an increase in grain size for the first 10 days following fertilization. A ¹⁴C-labeling study revealed that 8-day-old grains accumulated more dry matter into the ethanol-insoluble fraction when grown on agar rather than when immersed in liquid medium. Light enhanced the absorption of sucrose from the medium only in the latter case. In agar-based culture, when no contact was made between the grain surface and the medium, peeling off the outer pericarp layers increased sugar absorption, leading to a threefold increase in the amount of accumulated dry matter in the ethanol-insoluble fraction. Culturing of wheat grains with attached rachis fragment and peeled pericarp is recommended for maximum in vitro growth.