Sugar Supplements Research Articles

Diet-induced obesity and spatial cognition in young male rats

Recent work suggests that obesity may adversely affect cognitive behavior. To examine this suggestion, the effects of feeding a standard chow diet, and either supplemental sugar or fat on the development of obesity and performance on a test of spatial learning, the Morris Water Maze (MWM), were assessed in young male Long–Evans rats. Rats given access to a sucrose solution or dietary fat in addition to the chow diet consumed approximately 10% more calories per day, gained more weight, and had larger epididymal fat pads than rats fed the chow diet alone. Moreover, rats fed the supplemental sucrose took significantly more time to find a hidden platform in the MWM than rats fed the chow diet alone or chow and supplemental fat. Additionally, when tested 10 days after the initial training trials, rats given sucrose displayed deficits in long-term spatial memory. After 6 weeks on the diets, fasting blood glucose and serum triglyceride concentrations were significantly higher in sucrose-fed rats than in rats eating only the standard diet. These results indicate that diet-induced obesity resulting from excess sucrose intake, but not fat intake, in young animals impairs spatial learning and memory. It is hypothesized that these deficits arise from metabolic insults that leave the brain vulnerable to alterations in insulin sensitivity and glucose metabolism.

Effects of feeding frequency and sugar concentrations on lifetime reproductive success of Meteorus pulchricornis (Hymenoptera: Braconidae)

Many species of parasitoids can increase their reproduction through feeding on supplemental sugar sources. We evaluated the longevity both with and without hosts and progeny production of a uniparental strain of Meteorus pulchricornis by varying concentration of the sugar solution and feeding frequency. A 1:1:1 sucrose–glucose–fructose-mixture was tested in a range of concentrations (0–70% (w/v)). The parasitoid lifespan did not increase with the concentration of sugar solutions, but parasitoids feeding on a 30% sugar solution attained greater longevity than parasitoids feeding on other sugar concentrations in the absence of hosts. The same effect of sugar concentration was also observed on progeny production, where when the parasitoid was fed 30% (w/v) sugar solution, its lifetime progeny production doubled in comparison to that fed water, and increased by 50% compared to those fed the other sugar solutions. In the last experiment, we studied the effect of feeding intervals on the longevity and progeny production of M. pulchricornis. Parasitoids fed with a 30% (w/v) 1:1:1 sucrose–glucose–fructose-mixture continuously lived six times longer than unfed parasitoids, three times longer than parasitoids fed only once and two times longer than parasitoids fed once every two days in the absence of hosts. Parasitoids with continuous access to the sugar solution produced considerably more progeny than those with fewer feeding frequencies. This increasing progeny production was accomplished more through an increase in daily offspring production rather than through extending reproductive lifespan.

Dietary sugars, serum and the biocide chlorhexidine digluconate modify the population and structural dynamics of mixed Candida albicans and Escherichia coli biofilms

Despite the increasing recognition of the role played by mixed species biofilms in health and disease, the behavior and factors modulating these biofilms remain elusive. We therefore compared the effect of serum, two dietary sugars (sucrose and galactose) and a biocide, chlorhexidine digluconate, on a dual species biofilm (DSB) of Candida albicans and Escherichia coli and, their single species biofilm (SSB) counterparts. Both modes of biofilm growth on polystyrene plastic surfaces were quantified using a viable cell count method and visualized using confocal scanning laser microscopy (CSLM). Present data indicate that co-culture of C. albicans with varying initial concentrations of E. coli leads to a significant inhibition of yeast growth (r=-0.964; p<0.001). Parallel ultrastructural studies using CSLM and a Live/Dead stain confirmed that E. coli growth rendered blastospores and hyphal yeasts non-viable in DSB. SSB of C. albicans showed pronounced growth when its growth surface was pretreated with serum and by sugar supplements in the incubating medium (p<0.05). Intriguingly, C. albicans in DSB was more resistant to the antiseptic effect of chlorhexidine digluconate. Taken together, the current data elucidate some features of the colonization resistance offered by bacteria in mixed bacterial/fungal habitats and how such phenomena may contribute to the development of fungal superinfection during antimicrobial therapy.

Butanol production from wheat straw by simultaneous saccharification and fermentation using Clostridium beijerinckii: Part II—Fed-batch fermentation

Abstract In these studies, Clostridium beijerinckii P260 was used to produce butanol (acetone–butanol–ethanol, or ABE) from wheat straw (WS) hydrolysate in a fed-batch reactor. It has been demonstrated that simultaneous hydrolysis of WS to achieve 100% hydrolysis to simple sugars (to the extent achievable under present conditions) and fermentation to butanol is possible. In addition to WS, the reactor was fed with a sugar solution containing glucose, xylose, arabinose, galactose, and mannose. The culture utilized all of the above sugars. It was noticed that near the end of fermentation (286–533 h), the culture had difficulties utilizing xylose. As a result of supplemental sugar feed to the reactor, ABE productivity was improved by 16% as compared with previous studies. In our previous experiment on simultaneous saccharification of WS and fermentation to butanol, a productivity of 0.31 g L −1 h −1 was observed, while in the present studies a productivity of 0.36 g L −1 h −1 was observed. It should be noted that a productivity of 0.77 g L −1 h −1 was observed when the culture was highly active. The fed-batch fermentation was operated for 533 h. It should be noted that C. beijerinckii P260 can be used to produce butanol from WS in integrated fermentations.

Fatty acids synthesized by oral treponemes in chemically defined media

OMIZ-W68, a chemically defined medium that contains no long-chain fatty acids and yet supports in vitro proliferation of a wide range of fastidious oral anaerobes, is described. The type strains of Treponema denticola, Treponema lecithinolyticum, Treponema maltophilum, Treponema pectinovorum, Treponema socranskii, and an as yet unpublished canine Treponema species could be propagated indefinitely in this medium with sugar supplements for the saccharolytic species. Analysis of the cellular fatty acids (CFA) of these treponemes by gas chromatography demonstrated the synthesis of C14, C15, C16, and C17 fatty acids (linear-, iso-, and anteiso-forms) in various proportions, but neither hydroxy- nor unsaturated fatty acids. However, between 0% and 40% of the eluted material could not be identified. The proportions of CFAs differed not only between species but also between the eight strains of Treponema denticola investigated. Replacing OMIZ-W68 by a derivative minimal essential medium (OMIZ-M/TDCDK) developed for Treponema denticola had little effect on the CFA profiles. In contrast, the CFA profiles of treponemes grown in OMIZ-W68 showed at best minor similarity to the strains from the Moore library of the Virginia Polytechnic Institute, which had been grown in media containing serum, peptones, and yeast extract.

Longevity, fecundity, and progeny sex ratio of Pteromalus cerealellae in relation to diet, host provision, and mating

We investigated the effects of diet (sugar feeding), host provision, and mating on the longevity, fecundity, and progeny sex ratio of Pteromalus cerealellae (Ashmead) (Hymenoptera: Pteromalidae), an ectoparasitoid of several stored-product insects. Sugar feeding (25% sucrose solution) increased male lifespan by a factor of 3–4 relative to sugar-starved (provided water only) or completely starved (provided no water and no sugar solution) males, irrespective of mating status or host provision. Sugar feeding also increased longevity of females which were not provided hosts, but had no effect on longevity of females which were provided hosts, suggesting that supplemental sugar feeding is beneficial to females only in the absence of hosts. Females had a significantly greater longevity than males: Mean (± SE) longevity of sugar-fed unmated females provisioned with no hosts (36.3 ± 1.2 days) was significantly greater than mean longevity of sugar-fed unmated males provisioned with no hosts (29.7 ± 0.9 days). A negative effect of mating on longevity was recorded only in the absence of hosts but not when hosts were provided. In general, sugar feeding resulted in a modest increase in progeny production by female P. cerealellae and this was significant for one batch of attacked hosts. However, cumulative lifetime progeny (mean ± SE) of sugar-fed females (64.2 ± 9.2) was not significantly greater than that of sugar-starved (44.5 ± 6.8), or completely starved (54.5 ± 9.3) females. Nevertheless, progeny of sugar-fed females was female-biased (53% females) compared to male-biased progeny recorded for completely-starved females (37% females). These results suggest the potential impact of sugar feeding on survival, fecundity, and sex allocation in P. cerealellae.

Phosphate starvation responses are mediated by sugar signaling in Arabidopsis

Phosphate (Pi) is one of the least available plant nutrients in soils. It is associated with dynamic changes in carbon fluxes and several crucial processes that regulate plant growth and development. Pi levels regulate the expression of large number of genes including those involved in photosynthesis and carbon metabolism. Herein we show that sugar is required for Pi starvation responses including changes in root architecture and expression of phosphate starvation induced (PSI) genes in Arabidopsis. Active photosynthesis or the supplementation of sugar in the medium was essential for the expression of PSI genes under Pi limiting conditions. Expression of these genes was not only induced by sucrose but also detected, albeit at reduced levels, with other metabolizable sugars. Non-metabolizable sugar analogs did not induce the expression of PSI genes. Although sugar input appears to be down-stream of initial Pi sensing, it is absolutely required for the completion of the PSI signaling pathway. Altered expression of PSI genes in the hexokinase signaling mutant gin2 indicates that hexokinase-dependent signaling is involved in this process. The study provides evidence for requirement of sugars in PSI signaling and evokes a role for hexokinase in some components of Pi response mechanism.

Effects of nonstructural carbohydrate level and starch:sugar ratio on microbial metabolism in continuous culture of rumen contents

A dual flow continuous culture system was used to examine the effects of varying sugar as a proportion of sugar plus starch (NSC) at three concentrations of NSC on nutrient digestibility, ruminal fermentation and microbial growth. Diets contained 240, 280 and 330 g NSC/kg DM. At each NSC level, diets contained 29, 63 and 95 g sugar/kg DM. Corn grain and corn silage were the major starch sources. Liquid sugar blend (LSB) was the supplemental sugar source. Negative responses with interactions were seen at the 63 g sugar/kg DM level compared to no added sugar or 95 g sugar/kg DM in microbial growth, dry matter digested, protein digested, and total carbohydrate digested. Interactions resulted mostly because the negative responses to the 63 g sugar/kg DM were with the 240 and 280 g NSC/kg DM levels, but not with the 330 g NSC/kg DM level. Sugar addition depressed fiber digestion only with the 240 g NSC/kg DM level. At 330 g NSC/kg DM, all sugar substitutions were beneficial. Microbial responses were highest on the 330 g NSC/kg DM diet with 95 g sugar/kg DM, in which sugar made up 290 g/kg of the total NSC. Sugar additions at 95 g sugar/kg DM resulted in large increases in butyrate production. All sugar levels decreased acetate production but had little effect on propionate production.

Involvement of α-Amylase I-1 in Starch Degradation in Rice Chloroplasts

To determine the role of alpha-amylase isoform I-1 in the degradation of starch in rice leaf chloroplasts, we generated a series of transgenic rice plants with suppressed expression or overexpression of alpha-amylase I-1. In the lines with suppressed expression of alpha-amylase I-1 at both the mRNA and protein levels, seed germination and seedling growth were markedly delayed in comparison with those in the wild-type plants. However, the growth retardation was overcome by supplementation of sugars. Interestingly, a significant increase of starch accumulation in the young leaf tissues was observed under a sugar-supplemented condition. In contrast, the starch content of leaves was reduced in the plants overexpressing alpha-amylase I-1. In immunocytochemical analysis with specific anti-alpha-amylase I-1 antiserum, immuno-gold particles deposited in the chloroplasts and extracellular space in young leaf cells. We further examined the expression and targeting of alpha-amylase I-1 fused with the green fluorescent protein in re-differentiated green cells, and showed that the fluorescence of the expressed fusion protein co-localized with the chlorophyll autofluorescence in the transgenic cells. In addition, mature protein species of alpha-amylase I-1 bearing an oligosaccharide side chain were detected in the isolated chloroplasts. Based on these results, we concluded that alpha-amylase I-1 targets the chloroplasts through the endoplasmic reticulum-Golgi system and plays a significant role in the starch degradation in rice leaves.

Alternative to Off-Season Sugar Supplement Feeding of Honeybees

An experiment was conducted at Gorkha Bee Farm, Yagyapuri, Chitwan during rainy season of 2005 to investigate alternative to sugar supplement feeding and reduce cost feeding during off- season. Apis mellifera L. honeybee colonies were prepared with 5 frames of covering bees and 3.5 frames of broods and a queen of similar quality each of five different supplemental feedings: i) sugar syrup (1:1 sugar and water); ii) rice bran syrup (100 gm rice bran soaked in 1 lit water and after 4 hours blended, filtered and added 200 gm sugar + 20 gm honey and required water to make 1 lit); iii) maize syrup (100 gm maize flour soaked in 1 lit water and after 4 hours blended, filtered and added 200 gm sugar + 20 gm honey and required water to make 1 lit); iv) banana syrup (100 gm ripen peeled banana mixed in 1 lit water, blended, filtered and added 200 gm sugar + 20 gm honey and required water to make 1 lit); and v) pumpkin syrup (100 gm boiled pumpkin after removing outer hard core mixed in 1 lit water, blended, filtered and added 200 gm sugar + 20 gm honey and required water to make 1 lit) was placed inside the hive in a division board feeder @ 30 ml per frame of honeybees per day at an interval of 3 days. Feeding honeybees with sugar syrup increased number of brood cells by 53.5%, brood frames by 37.1% and frames covered by bees by 32.0%. Honeybee colonies when fed with banana and pumpkin syrup increased brood cells by 16.3% and 2.8%, brood frames by 17.1% and 8.6% and bees covered number of frames by 12.0% and 3.2%, respectively. Number of brood cells, brood frames and covered frames by bee remained almost constant when honeybees fed with pumpkin syrup. On the other hand, feeding bee colonies with maize and rice bran syrup decreased the number of brood cells by 11.2% and 35.2%, brood frames by 11.4% and11.4% and bees covered frames by 24.0% and 24.0%, respectively. The cost of off-season feeding was the highest (Rs. 247.0) for sugar syrup followed by maize syrup (Rs. 140.4), banana syrup (Rs. 117.4), rice bran (Rs. 113.4), and pumpkin syrup (Rs.105.4). All of the feeding materials were safe to bee feeding. Banana syrup feeding was found superior to others, and therefore, its supplementation can reduce the cost of sugar feeding by more than 50% and increase brood production during off-season. &#x0D; &#x0D; Key words: Off- season, honeybee feeding, sugar supplement&#x0D; &#x0D; J. Inst. Agric. Anim. Sci. 26:77-81 (2005)

Effects of Temperature, Sugar Availability, Gender, Mating, and Size on the Longevity of Phorid FlyPseudacteon tricuspis(Diptera: Phoridae)

The phorid sy,Pseudacteontricuspis Borgmeier, has been released for biological control of red imported Þre ant,Solenopisinvicta Buren, in many parts of the southern United States. However, little is known about the nutritional ecology and the effects of environmental and physiological factors on lifespan of adult phorid sies under laboratory or Þeld conditions. Here we report the effects of sugar feeding, temperature, gender, mating, and body size on longevity of P. tricuspis. Sugar availability and temperature were the two major factors insuencing longevity. In general, sugar feeding increased lifespan by a factor of 2Ð3. Longevity of P. tricuspis was inversely related to temperature, and the greatest longevity (15 d) was recorded for sugar-fed sies kept at 20C. Longevity declined from 15 da t 20C to 4 d at 33C for sugar-fed females and from 7 d at 20 Ct o 2da t 33C for sugar-starved females. Similar results were obtained for male P. tricuspis, and gender or mating did not signiÞcantly insuence longevity. There was no signiÞcant difference in longevity between mated and unmated female and male sies, irrespective of diet and temperature. Gender, however, had a signiÞcant effect on wing length with females being larger than males. A positive correlation between wing length and longevity was recorded for sugar-starved female and male phorid sies kept at 20C and for sugar-starved males kept at 28C, but not for sugar-fed sies or sies exposed to high temperatures. These results suggest that provision of supplemental sugar sources and suitable microclimate near its release sites may enhance the success of P. tricuspis as a biological control agent.

Microbial association and acidity development of unheated and pasteurized green-table olives fermented using glucose or sucrose supplements at various levels

Green-table olives, unheated and pasteurized, of Greek cultivar Conservolea were supplemented with glucose or sucrose in various amounts inoculated with Lactobacillus plantarum and fermentation was conducted. Although sugar supplements did not affect the lactic acid bacteria growth rate, they increased the rate of pH drop and the production of acids and lowered the final pH values in all cases. Adequate supplements of sugars (0.5%, 1.0% wv−1), of both types, in unheated olive fermentation, resulted in a fast pH drop, causing a satisfactory halt of Enterobacteriaceae growth in the first days of fermentation, and a subsequent population decline occurred in the following days, eliminating the danger of early stage spoilage and ensuring the safety of the final product. In pasteurized olives, where L. plantarum starter was the only microbial flora, it was considered worth evaluating the fermentation progress without any competition. The rate of pH drop was not as high as in unheated olives, but final pH values and acid development were more pronounced. Lactic acid was the predominant acid developed in both unheated and pasteurized olive fermentation, and increased sugar supplements resulted in faster production and higher yields of this acid. Acetic acid was also produced in low amounts at the end of fermentation, except in the cases of pasteurized olive fermentation supplemented with sucrose, where acetic acid was absent. A switch from homo-fermentative to hetero-fermentative metabolism might have taken place in case of glucose presence, but the same was not observed for sucrose.

Stevioside

Stevioside is a natural sweetener extracted from leaves of Stevia rebaudiana (Bertoni) Bertoni. The literature about Stevia, the occurrence of its sweeteners, their biosynthetic pathway and toxicological aspects are discussed. Injection experiments or perfusion experiments of organs are considered as not relevant for the use of Stevia or stevioside as food, and therefore these studies are not included in this review. The metabolism of stevioside is discussed in relation with the possible formation of steviol. Different mutagenicity studies as well as studies on carcinogenicity are discussed. Acute and subacute toxicity studies revealed a very low toxicity of Stevia and stevioside. Fertility and teratogenicity studies are discussed as well as the effects on the bio-availability of other nutrients in the diet. The conclusion is that Stevia and stevioside are safe when used as a sweetener. It is suited for both diabetics, and PKU patients, as well as for obese persons intending to lose weight by avoiding sugar supplements in the diet. No allergic reactions to it seem to exist.

Effect of particle size and supplemental sugar beet pulp on in vitro fermentation of high temperature dried alfalfa incubated with an equine faecal inoculum

The fibrous forage high temperature dried (HT) alfalfa has been fed to horses for a number of years because of its consistently high nutritive value. It is common practise in the UK to combine HT alfalfa either chopped or in a ground and pelleted form with sugar beet pulp (SB) as this is regarded as a nutritious feed for horses. Synergistic effects of sugar beet when added to fibre-based diets have been observed in other species (Longland et al., 1994) whereby the digestibility of graminaceous forages has been increased. However, such effects have been little examined in horses and there is a lack of information in the literature on the effects of SB on the digestibility of leguminous forages. Thus, the effect of sugar beet on the in vitro fermentation of ground and chopped HT alfalfa by an equid hind-gut microflora using the pressure transducer technique of Theodorou et al. (1994) was investigated.

Effect of diet on biting, oviposition, and survival of Aedes aegypti (Diptera: Culicidae).

The effect of adult diet on host biting, sugar probing and water probing patterns, oviposition behavior, and survival of Aedes aegypti (L.) from Charters Towers, Australia, were tested in the laboratory. The 7 diets were as follows: (1) starvation, (2) water, (3) 10% sugar, (4) blood, (5) blood with water supplement, (6) blood with 10% sugar supplement, and (7) blood with 3% sugar supplement. Biting, probing, oviposition, and survival observations were made every 6 h (0600-0800 hours, 1200-1400 hours, 1800-2000 hours, 2400-0200 hours). Biting frequency on the blood with 3% sugar diet (0.26 feeds per mosquito per 6 h) and the blood with 10% sugar diet (0.23 feeds per mosquito per 6 h) was significantly less than on blood (0.51 feeds per mosquito per 6 h) and 10% sugar (0.40 feeds per mosquito per 6 h) alone. Biting frequency was not significantly different between blood with water (0.47 feeds per mosquito per 6 h) and blood alone (0.51 feeds per mosquito per 6 h). Biting and oviposition occurred throughout the day, peaking between 1800 and 2000 hours and between 2000 and 2400 hours, respectively. Biting frequency with a 3% sugar supplement decreased after the 1st oviposition cycle on day 6 compared with unsupplemented biting. The presence of sugar delayed or inhibited oviposition. Females with access to blood with water bit and oviposited concurrently on days 4-6, 8-9, and 11, indicating a 3-d gonotrophic cycle. Survival on blood alone was not significantly lower than survival on sugar and water supplemented diets. Behavior of the Charters Towers strain proved to be significantly influenced by diet, and biting occurred opportunistically without regard for previously observed crepuscular or diurnal rhythms. The biting frequencies observed were the highest yet recorded for this species, which indicates that the vectorial capacity of the Australian Ae. aegypti may be underestimated severely.

Human Glycosylation Disorders and Sugar Supplement Therapy

Some genetic defects in protein glycosylation can be treated effectively with dietary supplements of monosaccharides. An easy screening test and non-toxic therapy for potentially lethal disorders should encourage physicians to search for more patients with glycosylation disorders. It should also stimulate research on the occurrence and availability of monosaccharides used for glycoconjugate synthesis and for vertebrate models to study their utilization.

Practitioner-Based Nutrition Advice for Chronic Fatigue Syndrome Varies

Chronic fatigue syndrome (CFS) is a vaguely identified disorder characterized by various persistent symptoms, including fatigue, sore throat, mild fever, muscle pain and weakness, depression, and lack of mental clarity. Nutritional aspects related to CFS have received little attention despite the fact that the syndrome is associated with a number of characteristics which may increase nutritional risk. A questionnaire was mailed to health care practitioners: 200 medical doctors (MDs), 200 doctors of osteopathic medicine (DOs), and 200 doctors of chiropractic (DCs) to determine whether nutrition was among recommendations given to CFS patients and whether these practitioners perceived these recommendations as beneficial. Response rate was 33% of subjects receiving the survey instrument: 72 MDs (39%), 55 DOs (30%), and 58 DCs (31%). Fifty-seven percent of 139 respondents (38% of MDs, 58% of DOs, and 69% of DCs) replied that they used nutrition therapies when treating CFS patients. Nutrition advice varied widely. Recommendations included low sugar, low caffeine, low fat, yeast-free, hypoallergenic, and low sodium diets and supplements of multivitamin/mineral, single vitamin, herbal remedy, single mineral, and homeopathy. Use of yeast-free diets varied by practice group, with DCs most likely and MDs least likely to report it (p<0.01). No MDs used homeopathy. DCs were most likely (64%) and MDs least likely (24%) to perceive improvement due to nutrition therapy (p<0.05); this difference may be confounded by other variables that differ between these types of practice. Due to the wide array of advice reported and the very small numbers of CFS patients per subject, no conclusions could be drawn regarding promising therapies, using this empirical approach.

Long-term effects of several biochemical and physical factors on cellulose biosynthesis in callus and suspension cultures of normal and mutant barley (Hordeum vulgare L.) strains producing less cellulose

To clarify a low level of cellulose biosynthesis of thein vitro cultured cells, the effects of several biochemical factors such as carbon sources (sucrose, maltose, and UDPG), antioxidants (ascorbic acid and glutathione) and physical factors such as artificial pressure, high gravity, on the cellulose production in barley callus and suspension cultures were investigated. In the suspension culture of two barley strains, the supplement of different concentrations (0, 1.5, 3.0, and 4.5%) of sucrose or maltose into the medium for 30 days did not promote the cellulose production and 4.5% of sugar supplement was rather inhibitory in one strain. However, in the presence of sucrose at 3%, UDPG (3 or 10 mM) supplement, as a precursor for cellulose, promoted 1.2–13 fold of the production in two strains. A low concentration (3 mM) of ascorbic acid and glutathione promoted 1.5 and 1.2 fold of the production in two strains, respectively. These results suggest that low cellulose biosynthesis of thein vitro cultured cells is due to a decreased level of the UDPG in the cytosol, and that the oxidative condition of external medium impedes cellulose synthesis in some manners. Artificial pressure applied to the callus promoted 1.4 fold of the cellulose production. High gravity (5,000 or 10,000g) applied to the suspension-cultured cells by centrifugation did not cause a substantial change.

Kinetics of plasma fructose and glucose when lactose and fructose are used as energy supplements for neonatal calves.

Shortly after birth, plasma glucose and fructose concentrations of the neonate decline and thus leave blood sugar below the homeostatic mode. Two trials were conducted to determine the plasma glucose and fructose kinetics in control and supplemented calves for 108 h after birth. In the short-term trial, six Holstein calves were given 40 g of either fructose, lactose, or water (control) orally at 1 and 96 h after birth. Treatments were administered with a colostrum substitute (Life Boost) at 1 h and whole milk at 96 h. Rectal temperatures and changes in plasma glucose and fructose concentrations were monitored at close intervals for 12 h after supplementation. In the long-term trial, 15 Holstein calves were given 40 g of either lactose, fructose, or water (control) at 1 h after birth and at 12-h intervals for 81 h. Plasma glucose and fructose concentrations were determined before and 4 h after each of the seven feedings. Early postpartal feeding of fructose suppressed plasma glucose (approximately 50%), with a reciprocal rise in plasma fructose. Irrespective of treatment, plasma glucose concentrations did not stabilize (approximately 100 mg/dL) until 17 to 24 h after birth. After 24 h, lactose supplements increased concentrations of plasma glucose 4 h after supplementation (169.7 +/- 8.2 mg/dL), compared with those in calves that did not receive the additional lactose. After 24 h, fructose supplements did not affect plasma glucose, but plasma fructose concentrations increased (82.6 +/- 12.4 mg/dL) 4 h after administration. The response to fructose supplements declined by 11.4 mg x dL(-1) x d(-1). Fructose was not detected in the plasma of control or lactose-treated calves after 17 h after birth. Calves that received fructose supplements had rectal temperatures 8 and 10 h after birth that were higher than those of the other calves. The mechanisms of sugar metabolism change quickly following birth. Oral sugar supplements increase the total plasma sugar concentrations of treated calves.

Role of high sugar concentrations in inducing somatic embryogenesis from cucumber cotyledons

We examined the effects of sucrose concentrations in initiation media with a constant carbohydrate molarity, and of osmotic potential provided by glucose or mannitol, on somatic embryogenesis from cotyledon explants of Cucumis sativus L. cv. ‘Shimoshirazu’. In constant carbohydrate molarity (0.25 M), the percentage embryo formation and the yield of embryos were enhanced by increasing sucrose concentrations. Sucrose (0.25 or 0.50 M) and glucose (0.50 M) both gave high frequencies of somatic embryogenesis; no embryos were formed when mannitol was the sole carbon source. When initiation media contained 0.25 M sucrose, raising the osmotic potential with either mannitol or glucose increased embryo yield and significantly promoted direct embryo formation. The percentage of bipolar embryos was also enhanced by increasing the molarity of carbohydrates in the initiation medium by the addition of glucose or mannitol. Glucose was a more effective sugar supplement than mannitol in inducing somatic embryos. Addition of 0.15 M glucose to the initiation medium containing 0.25 M sucrose resulted in the highest number of somatic embryos. Glucose had a specific carbon effect as well as an osmotic role. The specific carbon effect plays a major role and osmotic potential a minor and supplementary role in cucumber embryogenesis.