Carbohydrate formation in rewetted terrestrial cyanobacteria

Summary In the terrestrial cyanobacterium Nostoc commune Vauch. formation of carbohydrate polymers was measured upon rewetting the mats in a light-dark regime. To discriminate between carbohydrates of different physiological function, total carbohydrate was determined as anthrone-reactive material (ARM) and storage carbohydrate (glycogen) assayed by an enzymic test. In the dry thalli glycogen was found to represent less than one tenth of the ARM. After rewetting an increase of total carbohydrate was observed in illuminated samples. Only glycogen, however, showed a regular pattern of synthesis and degradation during a 12:12 h light-dark cycle. This indicates that most carbohydrates detected by anthrone belong to the metabolically inert sheath material.When illuminated colonies were kept submerged after rewetting glycogen was hydrolyzed indicative of being used in the rapid recovery of cellular functions as observed in rewetted colonies. Apparently, photosynthesis allowed for net glycogen synthesis only, provided the mats were sufficiently aerated. These findings give evidence that the (carbohydrate) sheath plays an important role in water retention in an organism bound to a terrestrial habitat.     

Utilization of reducing power in growing cultures of Chromatium

Summary The overall composition of cell material in the stationary growth phase of cultures of Chromatium strain 6412 cultivated with sulfide as electron donor is approximately (C₅H₈O₂N). At the moment that sulfide became depleted, 42% had been oxidized to sulfur and 58% to sulfate. Thus at this time 69% of the reducing power initially present had been utilized. However, the amount of structural cell material produced was only 56% of the amount present in the stationary phase of growth. This discrepancy appeared to be due to the accumulation of storage carbohydrate. Storage carbohydrate was synthesized as long as sulfide was available and consumed after sulfide depletion. Increase in structural cell material after sulfide depletion could not be accounted for by CO₂ fixation only, which indicates that storage carbohydrate can be converted into structural cell material. When stationary-phase cultures were again supplied with sulfide, growth was not observable in the first few hours, even though sulfide was oxidized, mainly to sulfur. Under these conditions reducing power was utilized for the synthesis of storage carbohydrate from CO₂.     

Evaluation of microwave radiation method for sample preparation of pine needles and wood for carbohydrate analysis

The aim of the current study was to test the suitability of microwave heating for stopping carbohydrate transformations in plant material. Needles and branches of Pinus sylvestris were treated in microwave oven (2.45 GHz, 800W) and compared to the samples treated in boiling ethanol (96 %). In extracts obtained from the microwaved material the ratio of sucrose to hexoses (glucose and fructose) decreased, while ethanol treatment resulted in stable extracts. The carbohydrate composition in dry samples estimated after a month of storage was persistent. The boiling of needles in ethanol in microwave oven gave the same results as boiling on a heating plate. In the woody material, differently from the needles, the total concentration of measured carbohydrates depended significantly on the preparation method. In the case of needles, the treatment of plant material in ethanol was better suited for the determination of carbohydrate levels than the microwave treatment.     

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.     

The composition,nutritional status and digestibility of the diets of Sarotherodon mossambicus from nine man-made lakes in Sri Lanka

Synopsis The dietary composition and the nutritional status and the digestibility of the diets of Sarotherodon mossambicus from nine reservoirs in Sri Lanka were evaluated. The feeding habits of S. mossambicus were variable from reservoir to reservoir; they ranged from herbivory to total carnivory. The protein, total lipid, carbohydrate and total organic matter content of the ingested material were related to the dietary composition and ranged from 18.53% to 35.15% (x−24.18%), 5.94% to 9.84% (x−7.91%), 11.6% to 34.7% (x−22.34%) and 34.4% to 64.4% (x−45.71%), respectively. Irrespective of the feeding habits, the diet contained a significant proportion of organic material which cannot be accounted for by protein, total lipid and carbohydrate. As much as the ingested material was related to the feeding habit, the digestibility of the nutrient components was related to the food material devoured. For example, the mean digestibility of the total organic matter in S. mossambicus feeding on detritus, plants and animal were 36.85, 33.5 and 29.5 respectively, and compared well with observations from elsewhere. It is hypothesised that the favourable nutrient quality of the available dietary material in the reservoirs of Sri Lanka, which could be and is effectively utilized by S. mossambicus, may have been, at least partially, responsible for its almost unprecedented success in Sri Lanka.     

An association of carbohydrates with particles of arabis mosaic virus retained within Xiphinema diversicaudatum

Sections through the odontophore of Xiphinema diversicaudatum showed two types of staining for carbohydrates using the periodic acid - thiosemicarbazide -silver proteinate (PA-TSC-SP) reaction. The first consisted of thin, localised, intensely-stained patches on the lining of the food canal of all the specimens examined. The second type, found only in nematodes exposed to AMV-infected plants, revealed cloud-like areas of carbohydrate - containing material associated with the stained patches on the lining of the food canal. By staining alternate sections with uranyl acetate/lead citrate, these carbohydrate clouds were shown to contain virus particles. Although the cloud material could have originated from either the plant or the nematode, sections through a pellet of partially purified virus particles prepared from plants did not stain for carbohydrate. The possible role of carbohydrate in virus retention and transmission is discussed.     

Breakdown of Douglas-fir phloem by a lignocellulose-degradingStreptomyces

An actinomycete,Streptomyces flavovirens, was shown to decay the intact cell walls of Douglas-fir phloem. Disks that had been cut from the inner bark were autoclaved, leached with sterile water, and inoculated withS. flavovirens. Decay produced by the actinomycete was observed by scanning electron microscopy, and the residual phloem was analyzed for weight loss and changes in carbohydrate and lignin content. After growth ofS. flavovirens for 12 weeks, inoculated disks had lost 47% of the leached dry weight, whereas sterile control disks had lost only 12%. The bulk of the material degraded by the actinomycete was carbohydrate. Scanning electron micrographs of decayed phloem disks showed irregular cavities in the cell walls of parenchyma and sclereids, with actinomycete hyphae penetrating these cavities.     

Vitis vinifera root and leaf metabolic composition during fruit maturation: implications of defoliation

Grapevine (Vitis vinifera) roots and leaves represent major carbohydrate and nitrogen (N) sources, either as recent assimilates, or mobilized from labile or storage pools. This study examined the response of root and leaf primary metabolism following defoliation treatments applied to fruiting vines during ripening. The objective was to link alterations in root and leaf metabolism to carbohydrate and N source functioning under conditions of increased fruit sink demand. Potted grapevine leaf area was adjusted near the start of véraison to 25 primary leaves per vine compared to 100 leaves for the control. An additional group of vines were completely defoliated. Fruit sugar and N content development was assessed, and root and leaf starch and N concentrations determined. An untargeted GC/MS approach was undertaken to evaluate root and leaf primary metabolite concentrations. Partial and full defoliation increased root carbohydrate source contribution towards berry sugar accumulation, evident through starch remobilization. Furthermore, root myo‐inositol metabolism played a distinct role during carbohydrate remobilization. Full defoliation induced shikimate pathway derived aromatic amino acid accumulation in roots, while arginine accumulated after full and partial defoliation. Likewise, various leaf amino acids accumulated after partial defoliation. These results suggest elevated root and leaf amino N source activity when leaf N availability is restricted during fruit ripening. Overall, this study provides novel information regarding the impact of leaf source restriction, on metabolic compositions of major carbohydrate and N sources during berry maturation. These results enhance the understanding of source organ carbon and N metabolism during fruit maturation.     

BIOCHEMICAL COMPOSITION AND METABOLIC ACTIVITY OF SCRIPPSIELLA TROCHOIDEA (DINOPHYCEAE) RESTING CYSTS1

The composition and metabolic activity of cysts of the marine dinoflagellate Scrippsiella trochoidea (Stein) Loeblich were examined during dormancy, quiescence, and germination. On a per cell basis, newly formed cysts contained an order of magnitude more carbohydrate but significantly less protein and chlorophyll a than did exponentially growing vegetative cells. Loss of lipid and carbohydrate from cysts during the initial dormancy period reflected a respiration rate estimated to be 10% of the respiratory activity in vegetative cells. Among older, quiescent cysts the calculated respiration rate decreased further to approximately 1.5% of the vegetative rate and appeared to proceed largely at the expense of carbohydrate reserves. These estimated rates of respiration were in good agreement with direct measurements of cyst oxygen consumption. The transfer of quiescent cysts to conditions permissive for germination resulted in a rapid increase in respiration rate, as evidenced by carbohydrate loss and O₂ consumption. The increased respiratory activity was followed by an increase in protein content and, later, by an increase in chlorophyll a content and photosynthetic capacity. Just prior to germination the P/R ratio became greater than 1, and the estimated chlorophyll-specific photosynthetic activity reached 75% of the rate in vegetative cells. Complete restoration of photosynthetic and respiratory capacity apparently was not achieved until after excystment. These data confirm the common assumption that dinoflagellate cysts represent true “resting” cells, containing extensive energy reserves and displaying greatly reduced metabolic activity.     

Influence of soil type,crop and air drying on residual carbohydrate content and aggregate stability after treatment with periodate and tetraborate

Summary The relationship between the water stability of microaggregates and the residual carbohydrate content of soil was examined in 15 soils from 7 soil series under various cultivations. The carbohydrate was progressively removed by increasing the time of treatment with 0.02M periodate and 0.1M tetraborate. The resulting decrease in reducing sugar content was significantly correlated with an increased disruption of microaggregates (>45 m) as determined by a turbidimetric method. The most effective treatment removed about 80% of the soil carbohydrate and caused an increase of about 75% in the fraction of microaggregates (<45 m) compared to untreated soil.15–20 percent of the soil carbohydrate was resistant to oxidation by periodate, even after prolonged reaction times and contained a higher relative proportion of glucose, arabinose, and xylose than the oxidised material. Sugars typical of microbial sources, mannose, galactose, rhamnose and fucose, were therefore preferentially oxidised by the periodate treatment.The grassland soils generally had higher carbohydrate contents than the arable soils and initially had a greater degree of aggregation. However, periodate oxidation affected each soil in its own characteristic manner. A significant inverse linear relationship between the degree of disruption and the residual sugar content was found with 13 of the 15 soils. Over the range measured aggregate stability was therefore related to the presence of carbohydrate predominantly from microbial sources.     

Composition of the cell wall of Chlorella fusca

Isolated cell walls of mature Chlorella fusca consisted of about 80% carbohydrate, 7% protein, and 13% unidentified material. Mannose and glucose were present in a ratio of about 2.7:1 and accounted for most of the carbohydrate. Minor components were glucuronic acid, rhamnose, and traces of other sugars; galactose was absent. After treatment with 2 M trifluoroacetic acid or with 80% acetic acid/HNO₃ (10/1, v/v), a residue with a mannose/glucose ratio of 0.3:1 was obtained, probably representing a structural polysaccharide. An X-ray diffraction diagram of the walls showed one diffuse reflection at 0.44 nm and no reflections characteristic of cellulose. Walls from young cells contained about 51% carbohydrate, 12% protein, and 37% unidentified material. Mannose and glucose were also the main sugars; their absolute amounts per wall increased 6–7 fold during cell growth. Walls isolated with omission of a dodecylsulphate/mercaptoethanol/urea extraction step had a higher protein content and, with young walls, a significantly higher glucose and fucose content. These data and other published cell wall analyses show a wide variability in cell wall composition of the members of the genus Chlorella.Abbreviations GLC gas liquid chromatography - TFA trifluoroacetic acid     

CELL PROLIFERATION IN COMPLEX TISSUES: THE CONTROL OF THE MITOTIC CYCLE OF CELL POPULATIONS IN THE CULTURED ROOT MERISTEM OF SUNFLOWER (HELIANTHUS)

Experiments were performed with cultured primary root tips of sunflower (Helianthus annuus var. Russian Mammoth) to determine: (1) if progression in the mitotic cycle of meristematic cells was nutritionally controllable by carbohydrate starvation and replenishment; (2) where in the mitotic cycle control was effected; and (3) whether nutritional deprivation could be used to detect phenotypically different subpopulations in a complex tissue. Meristematic cells were rendered stationary by carbohydrate starvation, as indicated by the absence of cell division; this condition was reversed by carbohydrate provision. After 72 or 96 hr of starvation most cells stopped in G1 (80–90%) and G2 (10–20%), and a very few (“leaky” cells) continued to enter S. “Leaky” cells represent a small population with an S period of approximately 4.1 hr that either lack a principal control point in G1 or have an unusual metabolism whereby the control point requirements are met and have a carbohydrate dependence for mitosis. Though phenotypically different, no specific functions can be attributed to “leaky” cells at this time.     

Glycogen in the Marine Protozoon Parauronema acutum*

SYNOPSIS. The carbohydrate which accumulates in the cytoplasm of the marine protozoon, Parauronema acutum, during normal growth was isolated, purified and characterized chemically. The highly purified material yielded only glucose residues following hydrolysis in 0.6 N HCl for 3 h at 100 C; measurement of total carbohydrate by the phenol-sulfuric acid method and by treatment with amylo-glucosidase and glucose oxidase gave similar values. Aqueous solutions of the purified material reacted with iodine to form a complex which exhibited an absorption peak at 456 nm with a shift to 484 nm in the presence of 50% saturated (NH₄)₂SO₄. Digestion with α-amylase, β-amylase, and isoamylase yielded 71%, 45% and 8.3% hydrolysis, respectively. Treatment sequentially with both isoamylase and β-amylase gave complete hydrolysis of the polymer. The average chain length (CL) determined by the isoamylase procedure was 12. These observations are consistent with the view that the carbohydrate isolated from the protozoan is a polymer consisting of α-D-glucose residues arranged in chains containing α-(1→4) linkages with branch points containing α-(1→6) linkages occurring once on the average of ～ 12 glucose residues and, as such, is indistinguishable from glycogen isolated from mammalian sources.     

Detection of protein and carbohydrate in the extracellular matrix released byCochliobolus heterostrophus during germination

The extracellular matrix (ECM) ofCochliobolus heterostrophus (anamorph:Bipolaris maydis) was made visible by gold/silver and FITC-lectin staining at different stages of germ tube development. A proteinaceous material was released from conidia as germ tubes began to emerge and continued to be released from the germ tube tip throughout elongation. A material that did not stain for protein was observed to surround germ tubes upon their elongation. At later stages of maturation, germ tubes were surrounded by a sheath of proteinaceous material. After 15 h of incubation, staining with the FITC-labeled Concanavalin A revealed that a carbohydrate material surrounded and extended between hyphae. The ECM extract was separated into two fractions which were shown by SDS-PAGE and HPLC analyses to consist of proteins and carbohydrates. The results demonstrate that the composition and physical structure of the ECM change over time. Thus, the ECM is not a static material. Rather, the components of the ECM appear to be laid down at different stages of fungal morphogenesis, possibly related to germ tube emergence, elongation, and maturation.     

Subcellular localization and glycoprotein nature of the invertase from the fission yeast Schizosaccharomyces pombe

The subcellular localization of the enzyme invertase in Schizosaccharomyces pombe cells, both repressed and derepressed for synthesis of the enzyme, was studied. Most of the invertase was found to be located outside the plasma membrane and only a small percentage was found to be associated to membranes. A substantial portion of the external enzyme remained firmly bound to cell-wall material.All of the invertase recovered in soluble form from cellular extracts reacted with concanavalin A and with the lectin from Bandeiraea simplicifolia seeds, indicating the presence in the enzyme of a carbohydrate moiety which probably contains terminal mannosyl (or structurally related) and galactosyl residues.The possibility of the presence of two different forms of invertase in S. pombe was considered. An intracellular, soluble form of invertase, devoid of carbohydrate, similar to the small invertase of the budding yeast Saccharomyces cerevisiae, was not found in S. pombe. However, the Michaelis constant for sucrose of the enzyme present in repressed cells was smaller than that of the invertase synthesized under derepressing conditions, although this difference could also be the result of a different pattern of glycosylation of the invertase synthesized under different growth conditions.     

Acquired Resistance in Hypersensitive Tobacco against Tobacco Mosaic Virus, Induced by Plant Cell Wall Components

Isolated cell walls from Nicotiana tabacum L. cv. Xanthi-nc were partially digested with enzymes present in the fungal preparation cellulase Onozuka R-10. Released carbohydrate material was separated from the enzymes by gel filtration and fractions were injected into the intercellular spaces of one half of each of several Xanthi-nc leaves. Two to three days after injection the whole leaves were inoculated with TMV. A large reduction in mean lesion diameter was observed in the injected areas compared with those in untreated tissue.     

PURIFICATION OF SPECIES SPECIFIC ANTIBODIES TO CARBOHYDRATE COMPONENTS OF MACROCYSTIS PYRIFERA (PHAEOPHYTA)1

Polyclonal rabbit antibodies to cell wall components were produced against gametophytes of the giant kelp Macrocystis pyrifera (Linnaeus) C. Agardh. These antibodies were found to react with carbohydrates extracted from M. pyrifera and Pterygophora californica Ruprecht by carbohydrate based enzyme immunoassay (EIA). The antibodies reacted with carbohydrates from both species. After affinity purification on a column with M. pyrifera carbohydrate coupled to AH-Sepharose, the eluted antibody was specific for M. pyrifera carbohydrate with little cross reactivity to P. californica carbohydrate in the EIA test. In experiments carried out to characterize the antigenic specificity of unfractionated antibody using commercially prepared carbohydrates in the EIA, the antibodies were shown to react primarily with fucoidan and to a lesser degree, alginate. The unfractionated antibody was also shown to bind to proteins from both M. pyrifera and P. californica. These results indicate that species specific carbohydrate determinants may be present in the kelp cell wall.     

Growth,body composition and digestive enzyme responses of Caspian Kutum,Rutilus frisii (Kamenskii, 1901), juveniles fed different levels of carbohydrates

The study evaluated the effects of dietary carbohydrate levels on growth performance and digestive enzyme activities in juveniles Caspian Kutum, Rutilus frisii (Kamenskii, 1901). Fish with an initial average weight of 0.8 ± 0.2 g (means ± SD) were fed five isonitrogenous and isoenergic formulated diets with different carbohydrate levels of 15%, 20%, 25%, 30% and 35% in triplicate groups for 10 weeks (fifteen 45‐L aquaria with 30 fish per tank and water temperature of 21.5–23.5°C). Based on the results, growth performance of Caspian Kutum was significantly improved by increasing carbohydrate levels from 15% to 35% (p < .05). A result of body composition analysis showed that the protein content was elevated with increasing carbohydrate levels (p < .05). Digestive enzyme activities were significantly influenced by dietary carbohydrate levels (p < .05). Trypsin, chymotrypsin, lipase and amylase specific activities increased significantly with rising carbohydrate levels from 15% to 35%. Alkaline phosphatase and N amino peptidase activities increased with carbohydrate levels increasing from 15% to 25%, but decreased with a further rise in the carbohydrate level from 25% to 35%. The results indicate that increasing carbohydrate levels from 15% to 35% have positive effects on growth parameters. However, carbohydrate amounts at levels higher than 35% and their effects on growth performance and digestive enzymes are not obvious, hence, more widespread studies on this nutrient are recommended.     

Sulphated polysaccharide synthesis in brown algae

Summary Histochemical and autoradiographic techniques have been used to investigate the sites of synthesis, transport and location of sulphated polysaccharides in some larger brown seaweeds.The most rapid uptake of ³⁵SO₄ occurred when material was incubated in medium with 10^-4M carrier sulphate, negligable uptake occurring from seawater.Autoradiography using ³⁵SO₄ has shown that in Pelvetia sulphated material is synthesised by all cell types, particularly epidermal cells. In Laminaria spp. this activity is confined to specialized secretory cells which discharge into mucilage canals. In both instances the process of carbohydrate sulphation appears to occur in the Golgi-rich perinuclear region.     

Determination of P status ofHevea brasiliensis by bark analysis

Summary The several methods to determine the P status ofHevea Brasiliensis on tropical soils are reviewed. The matter is very complicated, as several P compounds are found in soils,i.e. organic P, acid soluble P, exchangeable P, alkali-soluble P and inert P. It was found that P analyses of Hevea barks can better represent the amount of available P in the soil than soil analyses. Bark analyses are, moreover, less markedly influenced by date of sampling than leaf analyses. This characteristic feature of P in barks of Hevea may be ascribed to the outstanding property of energy-rich phosphorylated compounds as agents in increasing the synthesis of caoutchouc particles from the daily assimilates and the carbohydrate reserves.