Utilization of oligosaccharides by three pathogenic isolates of colletotrichum gloeosporioides

Summary Utilization of six oligosaccharides (viz., sucrose, maltose, cellobiose, lactose, raffinose and melezitose) by the isolates ofColletotrichum gloeosporioides Penz. causing leaf-spot diseases ofCarissa carandas L.,Eucalyptus robusta Sm. andBougainvillaea glabra Choizy has been studied. Daily chromatographic analysis of the culture medium revealed that the utilization of sucrose, maltose, cellobiose and raffinose was through a hydrolytic pathway. In case of lactose and melezitose no hydrolytic product could be detected. During the utilization of sucrose two oligosaccharides (Rf 0.27 and 0.2) made their appearance. TheBougainvillaea-isolate synthesized two oligosaccharides (Rf 0.18 and 0.1) in a maltose medium although no glucose could be traced, while in case of the other two isolates, in addition to these synthetic oligosaccharides, glucose also appeared. When theCarissa-isolate ofColletotrichum gloeosporioides was grown on a cellobiose medium, in addition to glucose, two synthetic oligosaccharides (Rf 0.15 and 0.11) were formed. Other two isolates showed the formation of one oligosaccharide (Rf 0.15) and no glucose. The dry weight of mycelium recorded an increase on oligosaccharides with slow rate of consumption, while on oligosaccharides with rapid rate of utilization it tended to become constant or showed a decline towards the end of the incubation.     

The effects of carbohydrates upon the survival and reproduction of adult female Pimpla turionellae L. (Hym., Ichneumonidae)

In this study the effects of 23 carbohydrates belonging to various groups upon the survival egg production and egg of female adult Pimpla turionellae L. were investigated. The best results among the carbohydrates tested was obtained with sucrose which was also employed as control. Glucose, maltose, trehalose and melezitose on the other hand showed no significant effect. The egg production was observed to be unaffected by glucose and maltose although it showed significant increase with trehalose and significant decrease with melezitose. Fructose and sorbitol caused a significant decrease in the survival of the insect. Fructose and sorbitol did not have any significant effect upon egg production whereas galactose caused a significant decrease. With the exception of galactose, no carbohydrate caused any significant effect upon egg hatching. Although they did not produce any eggs the female insects survived for 13.17, 15.13, 11.58 and 15.83 days in mannose, melibiose, raffinose and mannitol, respectively. The shortest life span was observed in arabinose followed by α-methyl- D -glucoside, dulcitol, rhamnose, cellobiose, xylose, starch, lactose, sarbose, ribose and glycogen.     

Physiological effect of sugars on various digestive enzymes ofSpodoptera littoralis larvae

Summary Feeding of Styropor lamellae treated with 0.25 M maltose, sucrose, raffinose or melezitose byS. littoralis larvae induced amylase activity to 5–6 fold and invertase and protease activity to 2–3 that of the control. Melibiose induced amylase activity to about 4-fold and invertase and protease activity to 188% and 173%, respectively, that of the control. -lactose stimulated the various digestive enzymes to various extents; cellobiose had practically no effect. Glucose and fructose induced the various digestive enzymes to about the same level but to a much higher extent than galactose.The feeding rate of the various sugar compounds except maltose, correlates well with their stimulating activity on the digestive enzymes. Maltose, which induced the larval digestive enzymes to about the same level as that of sucrose, elicited a considerably lower feeding response. The excretion index of sugars stimulating digestive enzymes and eliciting a feeding response, such as maltose, sucrose, raffinose and melezitose, is considerably lower than that of the other sugars.In a comparative test, sucrose, maltose and raffinose induced the various digestive enzymes to about the same level as their equivalent monosaccharide components. However, -lactose and cellobiose, which have the same components as melibiose and maltose but differ in their configuration, affect the various enzymatic systems weakly.Contribution from The Volcani Center, Agricultural Research Organization, Bet Dagan, Israel. 1972 Series, No. 2171-E. Definitions. Feeding response: express the intake of sugar plus insert Styropor carrier. Excretion index: ratio between weight of fecal pellets and Styropor lamellae consumed.The authors wish to thank Mr. K. R. S. Ascher for fruitful discussions, Dr. A. Genizi for statistical analysis of the results, Mrs. Sara Yablonski and Mrs. Shulamit Cohen for skillful technical assistance, and Mrs. Shoshana Hadad for insect rearing.     

Production of amylase(s) by Schwanniomyces castellii and Endomycopsis fibuligera

Schwanniomyces castellii and Endomycopsis fibuligera Produced extracellular amylase(s) when grown on various carbon sources and at different pH values. Both yeast species showed significant amylase synthesis in the presence of either maltose or soluble starch. On the other substrates tested (glucose, cellobiose, sucrose, trehalose, melezitose, raffinose, ethanol, glycerol) differences were found regarding growth and amylase production. Free glucose in the culture medium apparently inhibited enzyme synthesis. The pH range allowing maximal growth and amylase production was 4.5–6.0 for E. fibuligera and 5.5–7.0 for S. castellii.     

Specificity of yeast (Saccharomyces cerevisiae) in removing carbohydrates by fermentation

The specificity of Saccharomyces cerevisiae yeast on the removal of carbohydrates by fermentation was studied. The common monosaccharides, D-glucose, D-fructose, D-mannose, and D-galactose were completely removed; D-glucuronic acid and D-ribose were partially removed; but D-xylose, D-rhamnose, and L-sorbose were not removed and were completely resistant. Of four glycosides, methyl and phenyl alpha- and beta-D-glucopyranosides, three of the four were partially removed and methyl beta-D-glucopyranoside was not removed. The disaccharides, maltose, sucrose, and turanose were completely removed, while cellobiose, lactose, and melibiose were completely resistant. Isomaltose and alpha,alpha-trehalose were partially removed. Maltotriose and raffinose were partially removed, but isomaltotriose and melezitose were completely resistant. The tetrasaccharides, maltotetraose, isomaltotetraose, and acarbose, were completely resistant. Further, the yeast enzymes did not alter any of the resistant carbohydrates by transglycosylation or condensation reactions or by any other types of reactions.     

Sugar convertibility in the parasitoid Cotesia glomerata (Hymenoptera: Braconidae)

Lack of suitable sugar sources for adult parasitic wasps is an important cause of failure in biological control programs, but the metabolic constraints of sugar feeding are poorly understood. Here we investigated the suitability of 11 naturally occurring sugars as energy sources for the parasitoid Cotesia glomerata (L.) (Hymenoptera: Braconidae). By feeding energy-deprived individuals with given quantities of a 40% (w:w) sugar solution, we assessed recovery time and lifespan after feeding. More than 50% of the wasps recovered within 20 min, and at least 80% within 60 min after uptake of one of the monosaccharides fructose or glucose, the disaccharide sucrose, or the trisaccharide melezitose. Between 40 to 80% of the test insects recovered within an hour after intake of maltose, raffinose, galactose, or mannose. Less than 25% recovered within 1 h after uptake of melibiose, trehalose, rhamnose, or water (control). Parasitoids obtained the highest lifespan benefits after intake of glucose, fructose, sucrose, or melezitose, indicating and confirming their convertibility as an energy source for C. glomerata. In contrast, no lifespan increase was found after consumption of rhamnose and trehalose. The differences in recovery time and lifespan are discussed in terms of parasitoid enzyme activity and metabolic processes.     

Nutritional requirements and simplified cultivation medium to study growth and energetics of a sourdough lactic acid bacterium Lactobacillus fermentum Ogi E1 during heterolactic fermentation of starch

AIMS: Nutritional requirements of Lactobacillus fermentum Ogi E1 were studied in order to define a simplified fermentation medium. METHODS AND RESULTS: When grown with MRS-medium in 2l bioreactors, a biphasic pattern of growth and metabolite production was observed. Study of nutritional requirements resulted in a simplified medium (SYAM) that allowed, under anaerobiosis, similar results to be obtained as in MRS medium, but without biphasic fermentation kinetics. The best substrates for both growth and amylase production were starch and maltose. Although melibiose, raffinose, fructose, sucrose and glucose also supported growth, lower amylase activity was observed. CONCLUSION: The physiology of the strain can be investigated with SYAM medium, using either starch or maltose as substrate. The strain also presented potential for alpha-galactoside fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus fermentum was one of the dominant bacteria of African maize dough fermentations. Amylolytic strains with activity against other compounds (i.e. raffinose) suggested a potential to be used as starter for cereal fermentation.     

Transport and hydrolysis of disaccharides by Trichosporon cutaneum.

Trichosporon cutaneum is shown to utilize six disaccharides, cellobiose, maltose, lactose, sucrose, melibiose, and trehalose. T. cutaneum can thus be counted with the rather restricted group of yeasts (11 to 12% of all investigated) which can utilize lactose and melibiose. The half-saturation constants for uptake were 10 +/- 3 mM sucrose or lactose and 5 +/- 1 mM maltose, which is of the same order of magnitude as those reported for Saccharomyces cerevisiae. Our results indicate that maltose shares a common transport system with sucrose and that there may be some interaction between the uptake systems for lactose, cellobiose, and glucose. Lactose, cellobiose, and melibiose are hydrolyzed by cell wall-bound glycosidase(s), suggesting hydrolysis before or in connection with uptake. In contrast, maltose, sucrose, and trehalose seem to be taken up as such. The uptake of sucrose and lactose is dependent on a proton gradient across the cell membrane. In contrast, there were no indications of the involvement of gradients of H+, K+, or Na+ in the uptake of maltose. The uptake of lactose is to a large extent inducible, as is the corresponding glycosidase. Also the glycosidases for cellobiose, trehalose, and melibiose are inducible. In contrast, the uptake of sucrose and maltose and the corresponding glycosidases is constitutive.     

Inhibition of Camellia japonica Pollen Tube Growth by Maltose

Various oligosaccharides were studied with regard to their effecton the in vitro growth of Camellia japonica pollen tube. Sucrose,raffinose, melezitose, cellobiose, turanose and isomaltose,especially the first four, promoted pollen tube growth, whilemaltotriose, trehalose, gentiobiose, palatinose, melibiose,lactose and lactulose had little effect. Maltose strongly inhibitednot only the tube growth on sugar-free medium but also sugar-stimulatedgrowth, except in the case of sucrose stimulation. Glycosidaseactivities toward the growth-stimulating oligosaccharides weredetected in the extract of sucrose-grown pollen, but the activitiesof -glucosidase and -galactosidase were much lower than thoseof ß-fructosidase and ß-glucosidase. Maltosesuppressed the increase in UDP-glucose level of the glucose-grownpollen but not that of the sucrose-grown one. These resultssuggest that maltose acts, directly or indirectly, somewherein the pathway from glucose to UDP-glucose via glucose-1-phosphate,but does not interfere with the direct conversion of sucroseto UDP-glucose. (Received December 1, 1984; Accepted May 24, 1985)     

Variation in the fermentative pattern of some Saccharomyces species

Summary The acquisition of the ability to ferment galactose, maltose, sucrose, raffinose and melibiose by yeast strains of the genus Saccharomyces was investigated. During cultivation in selective media 11 strains belonging to 5 species gained the ability to ferment one or several of these sugars. De-adaptation was not usually observed after cultivation in glucose medium, indicating that the saltants are stable in this medium.     

A cell-associated oligo-1,6-alpha-glucosidase from an extremely thermophilic anaerobic bacterium, Thermoanaerobium Tok6-B1.

Cell-associated oligo-1,6-alpha-glucosidase (EC 3.2.1.10) was isolated from Thermoanaerobium Tok6-B1 grown on starch-containing medium. Activity was purified 11.4-fold by salt precipitation, gel filtration, hydroxyapatite and anion-exchange chromatography. Molecular mass was determined as 30,000 by SDS/polyacrylamide-gel electrophoresis and 33,000 by analytical gel filtration. The probable order of specificity was p-nitrophenyl-alpha D-glucose greater than-isomaltose greater than-isomaltotriose greater than-panose greater than-nigerose and no activity was shown against malto-oligosaccharides, melezitose, melibiose, raffinose, cellobiose, sophorose, gentiobiose, lactose, pullulan, dextran or amylose. The optima for activity and stability were between pH 5.6 and 7.0 and the half-life at pH 6.5 was 1000 min at 70 degrees C and 20 min at 76 degrees C. Activity was stabilized by substrate, Mg2+, Mn2+ and Ca2+, but was destabilized by Zn2+ and EDTA. N-Ethylmaleimide, glucose and 1-O-methyl-alpha D-glucose were inhibitory but 1-O-methyl-beta D-glucose stimulated activity. The activation energy (Ea) was 109 kJ/mol.     

Effects of culture conditions on isolated microspore response of barley cultivar Igri

Pretreatment of anthers in mannitol prior to isolation of microspores by glass rod homogenization was effective for in vitro induction of embryogenesis in barley cv. Igri. A procedure for separation of viable microspores using centrifugation on 20% maltose was developed. The concentration of microspores was important and greatly increased the number of developing structures. Initial culture of microspores on FHG medium containing 62 g l^-1 maltose, 4.4 M (1 mg l^-1) BA and 200 g l^-1 Ficoll-400 resulted in high frequencies of plant regeneration. Albino plant frequency was correlated to length of time in culture. Stock plant condition appeared to be a major factor influencing induction frequency. From 868 to 1738 green plants per 100 anthers were produced. The number of calli and embryos obtained and the number of green plantlets regenerated were improved by increasing the Ficoll concentration from 100 g l^-1 to 400 g l^-1 during the culture period compared to continuous culture on FHG Ficoll 200 g l^-1.Abbreviations BA benzyladenine     

Microspore culture in Corchorus olitorius: effect of growth regulators, temperature and sucrose on callus formation

Culture of isolated microspores and of anthers on media containing IAA directed free microspore development to an embryogenic pathway in C. olitorius. The first division of microspores on transfer to culture media was symmetrical in contrast to the asymmetrical division seen in normal development in vivo. Initially, 10-30% microspores divided symmetrically, but only 0.2-1% of the dividing microspores continued dividing and produced multicellular microcalli. About 30% of these microcalli produced callus but only on medium with 2.0 mg/L zeatin and 0.1 mg/L IAA. Incubation in the dark at temperatures of 35 degrees C for 1 day and then 25 degrees C was found effective for induction of first embryonic division in Corchorus. The frequency of microspore callus formation was higher on medium containing either 3% or 5% sucrose. Addition of colchicine and addition of activated charcoal to the above medium did not enhance microspore division in Corchorus olitorius. On transfer to different media most calli produced roots but regeneration of shoots and embryos was not induced.     

Aphid–ant mutualism: how honeydew sugars influence the behaviour of ant scouts

Honeydew is the keystone on which ant–aphid mutualism is built. The present study investigates how each sugar identified in Aphis fabae Scopoli honeydew acts upon the feeding and the laying of a recruitment trail by scouts of the aphid‐tending ant Lasius niger Linnaeus, and thus may enhance collective exploitation by the ant mutualists. The feeding preferences shown by L. niger for honeydew sugars are: melezitose = sucrose = raffinose > glucose = fructose > maltose = trehalose = melibiose = xylose. Although feeding is a prerequisite to the launching of trail recruitment, the reverse is not necessarily true: not all ingested sugar solutions elicit a trail‐laying behaviour among fed scouts. Trail mark laying is only triggered by raffinose, sucrose or melezitose, with the latter sugar being specific to honeydew. By comparing gustatory and recruitment responses of ant foragers to sugar food sources, the present study clarifies the role of honeydew composition both as a source of energy and as a mediator in ant–aphid interactions. Lasius niger feeding preferences can be related to the physiological suitability of each sugar (i.e. their detection by gustatory receptors as well as their ability to be digested and converted into energy). Regarding recruitment, the aphid‐synthesized oligosaccharide (melezitose) could be used by ant scouts as a cue indicative of a long‐lasting productive resource that is worthy of collective exploitation and defence against competitors or aphid predators.     

Kinetics,nutrition and inhibitor properties of basidiospore germination in schizophyllum commune

Summary The kinetics, nutritional requirements and inhibitor properties of basidiospore germination in the wood-rotting mushroom Schizophyllum commune were investigated. Measurements of changes in absorbancy and dry weight showed a lag period of approximately 15–20 hrs, followed by an abrupt increase in the rate of both processes. Individual basidiospore elongation also showed a lag phase and population changes were heterogenous in this regard.Carbohydrates active for basidiospore germination were grouped into four categories. Those sugars active between 15 and 20 hrs included glycogen, turanose, cellobiose, maltose, sucrose, glucose, fructose, mannose, galactose and xylose. Several sugar alcohols were only active between 30 and 60 hrs incubation and these included mannitol, sorbitol, ribitol, xylitol, arabitol, erythritol and glycerol. A third category of carbohydrates active for germination required prolonged incubation between 30 hrs and 7 days and included lactose, sorbose, raffinose, melezitose, trehalose, ribose and melibiose. Compounds without activity after 7 days included galactitol, inositol, acetate, succinate, gluconate, citrate, fumarate, rhamnose, fucose and inulin.Nitrogen sources active in basidiospore germination included complex organic nitrogenous substrates, asparagine, glutamine, arginine, urea and various ammonium salts.Germination was inhibited by cycloheximide, l-ethionine, p-fluoro-dl-phenylalanine, sodium azide, 2,4-dinitrophenol, phenylmercuric acetate and 2-deoxy-d-glucose. Alkali as a trapping agent arrested germination in glucose-(NH₄)₂SO₄ medium but was without ill-effect in glucose peptone broth.     

Responses of the ant Lasius niger to various compounds perceived as sweet in humans: a structure-activity relationship study

A behavioural study on the ant Lasius niger was performed by observing its feeding responses to 85 compounds presented in a two-choice situation (tested compound versus water control or sucrose solution). Among these compounds, only 21 were phagostimulating: six monosaccharides (D-glucose, 6-deoxy-D-glucose, L-galactose, L-fucose, D-fructose, L-sorbose), four derivatives of D-glucose (methyl alpha-D-glucoside, D-gluconolactone and 6-chloro- and 6-fluoro-deoxy-D-glucose), five disaccharides (sucrose, maltose, palatinose, turanose and isomaltose), one polyol glycoside (maltitol), three trisaccharides (melezitose, raffinose and maltotriose) and two polyols (sorbitol and L-iditol). None of the 16 non-carbohydrate non-polyol compounds tested, although perceived as sweet in humans, was found to be active in ants. The molar order of effectiveness of the major naturally occuring compounds (melezitose > sucrose = raffinose > D-glucose > D-fructose = maltose = sorbitol) is basically different from the molar order of their sweetness potency in humans (sucrose > D-fructose > melezitose > maltose > D-glucose = raffinose = sorbitol). On a molar basis melezitose is in L. niger about twice as effective as sucrose or raffinose, while D-glucose and D-fructose are three and four times less effective, respectively, than sucrose or raffinose. From a structure-activity relationship study it was inferred that the active monosaccharides and polyols should interact with the ant receptor through only one type of receptor, through the same binding pocket and the same binding residues, via a six-point interaction. The high effectiveness of melezitose in L. niger mirrors the feeding habits of these ants, which attend homopterans and are heavy feeders on their honeydew, which is very rich in this carbohydrate.     

梗孢酵母属的一个新种

作者于1978年从福建省福州市西湖公园的芒果花中分离出一株酵母1519。该菌株不产生子囊孢子、掷孢子,亦未见到有锁状连合。未发现有性繁殖。无性繁殖是在母细胞上产生小梗,小梗上产生子细胞,子细胞还可再生小梗再生子细胞。如果子细胞不脱落则成链状或分枝的链状。不发酵任何糖。按照形态和繁殖特征只符合Lodder(1970)酵母分类专著中半知菌部分的梗孢酵母。因此将它放入梗孢酵母属,命名为福州梗孢酵母(Sterigmatomyces fuzhouensis sp.n.)。     

Plutella xylostella (diamondback moth) and its parasitoid Diadegma semiclausum show different gustatory and longevity responses to a range of nectar and honeydew sugars

Parasitoids as well as many of their herbivorous hosts, depend on carbohydrate‐rich food during the adult stage. Different types of nectar and honeydew vary with regard to their sugar composition. In order to successfully exploit a food source, the insect must show a positive gustatory response to its component sugars and be able to digest and metabolise them. Here we tested the herbivore Plutella xylostella L. (Lepidoptera: Plutellidae) and its parasitoid Diadegma semiclausum (Hellén) (Ichneumonidae: Campopleginae) with respect to their feeding response and longevity when provided with one of nine sugars (fructose, glucose, lactose, maltose, melibiose, melezitose, raffinose, sucrose, or trehalose). Both species responded to and showed a prolonged life span on a broad range of sugars. The impact of food supply on life span was about sixfold higher for the parasitoid than for the herbivore. In general, there was a good fit between gustatory response and achieved longevity, with some outliers. Both species showed only weak responses to melibiose, which significantly prolonged life span. The parasitoid showed a gustatory response to melezitose, which did not prolong its life span. The parasitoid and its herbivorous host responded differently to trehalose. These differences in gustatory response and longevity show the potential for application of selective sugar sources in conservation biological control. At the same time it also reveals a risk that the indiscriminate application of sugar sources may stimulate herbivory.     

Extraction and quantification of the raffinosaccharides in soya bean

The raffinosaccharides and their possible metabolites can be rapidly and quantitatively extracted from soya bean with aqueous 80% methanol, and quantified by g.l.c. after trimethylsilylation or oximation and trimethylsilylation. The procedure has been applied variously to crude, defatted, untreated, heat-treated, and acid-treated soya bean without deproteinisation. l-Arabinose, l-rhamnose, d-fructose, d-glucose, d-galactose, d-mannose, sucrose, cellobiose, galactobiose, melibiose, raffinose, cellotriose, galactotriose, manninotriose, stachyose, verbascotetraose, and verbascose have been identified and quantified.