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PubMedDate not supplied

Relationship between body fat mass, carbohydrate tolerance and IRI response during glucose infusion in subjects with early diabetes.

We have studied the interrelationship of total body fat mass, carbohydrate tolerance and IRI response in 17 non-obese and obese subjects, who were suspected of having early diabetes. We carried out an i.v. glucose infusion test consisting of a priming injection of 0.33 g/kg followed by constant glucose infusion of 12 mg/kg/min in all persons. Total body fat mass was estimated by the tritium dilution method. There was a positive correlation of body fat mass, fasting glucose concentration and blood glucose concentration at 150 min as well as a strong correlation between body fat mass and BG area 60--120 min as parameters of carbohydrate tolerance in all subjects, i.e. the degree of carbohyrate intolerance was directly related to the quantity of total body fat mass. A similar correlation was found when the non-obese and obese groups were analyzed separately. In neither group did total body fat mass correlate with parameters of IRI response. In obese subjects with pathological carbohydrate tolerance, however, a positive correlation of basal IRI concentration and total body fat mass was found. Furthermore, a close relation between basal IRI level and parameters of carbohydrate tolerance could be demonstrated in obese subjects. The present study failed to demonstrate any correlation of parameters of carbohydrate tolerance and glucose-induced IRI response in either group. Thus, the significant relationship between body fat mass and degree of carbohydrate intolerance indicates that body fat mass plays an important role in the disturbance of blood glucose homeostasis in early diabetes with and without obesity.

Adipose Tissue↗

PubMed1979

Effects of differences in amount and kind of dietary carbohydrate on plasma glucose and insulin responses in man.

The effect of variations in kind and amount of dietary carbohydrate on plasma glucose and insulin responses was studied in normal subjects and in patients with chemical diabetes. Plasma glucose and insulin responses fell when the proportion of total calories given as carbohydrate were decreased by 15% (coincidental with a comparable increase in dietary fat). Associated with the lower plasma glucose and insulin concentrations was a fall in fasting and postprandial triglyceride levels. Plasma glucose and insulin responses were also lower when equivalent carbohydrate challenges were given as part of a mixed meal, as compared to a drink. Furthermore, carbohydrate given as starch also led to an attenuated glucose and insulin response when compared to an equivalent amount of glucose administered as either dextrose or sucrose. Finally, significant differences were also seen after the ingestion of different kinds of starch, with potato being the most like dextrose, and rice the least. These results indicate that differences in amount and kind of ingested carbohydrate can modify ensuing plasma glucose and insulin responses, and raise the possibility that such dietary manipulation may have some therapeutic utility in patients with abnormal carbohydrate and lipid metabolism.

Blood Glucose↗

PubMed1976

Protein-carbohydrate-lipid complex isolated from the cell envelopes of Chlamydia psittaci in alkaline buffer and ethylenediaminetetraacetate.

Exposure of isolated cell envelopes from purified infectious elementary (EB) of Chlamydia psittaci to sodium carbonate-bicarbonate buffer at pH 10 plus ethylenediaminetetraacetate (EDTA) results in partial solubilization of the total protein. The released materials represent 20% of the dry weight, 16% of the total protein, 40% of the total carbohydrate, and 9% of the total lipid of the cell envelopes. Sucrose density gradient centrifugation, and Sephadex G-200, Sepharose 4B, or diethylaminoethyl-cellulose column chromatography, reveal a protein-carbohydrate-lipid complex of several hundred thousand molecular weight that contains 50% protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the isolated EB cell envelopes reveals two major protein bands, A and B, with estimated molecular masses of approximately 85,000 and 53,000, respectively, both of which also stain for the presence of carbohydrate and lipid. Gel electrophoresis of the protein-carbohydrate-lipid complex reveals two protein bands, C and D, with estimated molecular weights of approximately 17,000 and 13,000, respectively, which contain lipid and a small amount of carbohydrate; bands A and B are not present in the complex. Gel electrophoresis of the cell envelope residues after extraction of the complex with alkali and EDTA shows a single main band, corresponding to the position of band B, which contains protein, carbohydrate, and lipid; band A is completely missing. B and A is believed to be a component of the complex, which is split into two subunits on alkali solubilization.

Bacterial Proteins↗

PubMed1978

Subclass restriction of murine anti-carbohydrate antibodies.

Examination of the subclass distribution of murine antibodies directed against groups A and C streptococcal carbohydrate, alpha-(1 leads to 3) dextran and phosphocholine yields the surprising observation that these carbohydrate antigens stimulate IgG responses largely restricted to the rare IgG3 subclass. This subclass restriction is particularly impressive in light of the low circulating levels of IgG3 in nonimmune mouse serum and the failure of a variety of other antigens including proteins and aromatic haptens to stimulate IgG3 antibody production. Attempts to alter the subclass restriction of antibodies with carbohydrate specificity by immunization with carbohydrate-coupled protein have been unsuccessful and indicate that immunoregulation of subclass expression probably occurs at the level of the antibody forming (B) cell. It is therefore conceivable that VH regions of murine immunoglobulins may be restricted to particular IgG subclasses. A similar type of subclass restriction has been reported in human and rat anti-carbohydrate antibodies. This recruitment of a minor immunoglobulin isotype by carbohydrate antigens in several species further supports the concept of immunoregulation at the level of subclass, and suggests that these and other mammals may share a structurally similar isotype with perhaps a common evolutionary origin.

Animals↗

PubMed1979

[Specific problems posed by carbohydrate utilization in the rainbow trout].

Carbohydrate incorporation in trout diets arises problems both at digestive and metabolic levels. Digestive utilization of carbohydrate closely depends on their molecular weight. In addition, in the case of complex carbohydrates (starches), different factors such as the level of incorporation, the amount consumed and the physical state of starch influence the digestibility. The measurement of digestibility in itself is confronted with methodological difficulties. The way the feces are collected can affect the digestion coefficient. Dietary carbohydrates actually serve as a source of energy. Nevertheless, above a certain level in the diet, intolerance phenomena may appear. The question that arises now is to establish the optimal part that carbohydrates can take in the metabolizable energy of a given diet.

Animals↗

PubMed1978

Nonsecreting myeloma variants with heavy-chain carbohydrate deficiencies.

Light- and heavy-chain synthesis was studied in six previously isolated S194-2 mouse myeloma variant lines and in the parent from which they were derived. Serological data and comparative analysis of the cyanogen bromide fragments obtained from variant and parent intracellular immunoglobulin showed that five variants which failed to secrete detectable amounts of IgA synthesized both heavy- and light-chain subunits. Whereas at least two heavy-chain populations were resolved in the parent line, one containing carbohydrate and one devoid of carbohydrate, only the heavy-chain fraction devoid of carbohydrate was detected in the variant lines. The correlation between carbohydrate deficiencies on the heavy chains and lack of immunoglobulin secretion in five independent subclones is discussed in terms of possible primary lesions and the role of carbohydrate in secretion.

Carbohydrate Metabolism↗

PubMed1976

Concanavalin A-perioxidase-diaminobenzidine (Con-A-PO-DAB)-alcian blue (AB): a reliable method for dual staining of complex carbohydrates.

A method has been established for the dual staining of complex carbohydrates in light microscopy. It is a combined concanavalin A-peroxidase-diaminobenzidine (Con-A-PO-DAB)-alcian blue (AB) (pH 2.5) method, and with this method it is possible to color alpha-D-glucosyl and alpha-D-mannosyl residues and acidic groupings of complex carbohydrates in tissues brown and blue respectively. Histochemical experiments using histological sections with reactive complex carbohydrates and casein films containing carbohydrates of known chemical structure have substantiated the validity of the above significance of the dual staining. Thus, the present dual staining method is a reliable one and a new addition to a series of dual staining techniques hitherto employed in the light microscopic histochemistry of complex carbohydrates.

3,3'-Diaminobenzidine↗

PubMed1979

Dietary carbohydrate and metabolism of ingested protein.

Six normal people were fed a lean beef meal while on a normal diet and after seven days on a very low carbohydrate (greater than 25 g/day) 2000 kcal/day diet. After carbohydrate restriction, the protein-induced rise in branched chain aminoacids was 40-50% greater than the rise after the control diet. Intravenous leucine also produced a 40% greater rise in plasma-leucine after carbohydrate restriction. Three days of fasting exaggerated protein-induced increases in plasma branched-chain aminoacids by 55-77%. Hypocaloric, pure carbohydrate refeeding restored the branched-chain aminoacid responses to normal. Severe carbohydrate restriction thus leads to increased accumulation of plasma branched-chain aminoacids after protein feeding which is at least in part due to reduced utilisation of these aminoacids.

Adult↗

PubMed2026

Synthesis and Application of a Suite of 2,5-Aryl Tetrazole Photoaffinity-Based Probes for Profiling Microbial Carbohydrate and Mucin Metabolism in Gut Microbiota.

Photoaffinity-based chemoproteomics provides a strategy for interrogating protein engagement and networks within complex biological systems. In the context of carbohydrate metabolism, however, linking the probe structure to glycan-processing networks remains challenging due to the diversity and redundancy of carbohydrate-active enzymes (CAZymes). Here, we employ 2,5-tetrazoles as photoreactive groups to develop a suite of monosaccharide-bearing probes designed to capture carbohydrate-associated protein environments in gut microorganisms. Across defined bacterial cultures and human fecal lysates, tetrazole probes enriched glycoside hydrolases (GHs) and additional carbohydrate-associated proteins, including transporters and regulatory elements. Notably, enrichment profiles were functionally biased toward glycan-processing modules, despite minimal shifts in global protein abundance under different growth conditions. These findings demonstrate that tetrazole chemoproteomics complements abundance-based proteomics by reporting on glycan-associated protein engagement and organization. Together, this probe suite provides a substrate-centric approach to studying carbohydrate-processing networks in defined microbes and complex microbiomes.

Tetrazoles↗

PubMed1979

Triglyceride integrated concentrations: effect of variation of source and amount of dietary carbohydrate.

The effect of changes in the amount of dietary carbohydrate (45 or 65% of total energy) and in the source of carbohydrate (sucrose or corn syrup) on plasma triglyceride and cholesterol concentrations was studied in eight healthy males. Subjects ingested each of the four formula diets for 10 days in a latin square sequence. Diet-induced response was assessed by measurement of plasma lipid concentrations in blood obtained after overnight fast and by measurement of the mean plasma lipid concentrations--designated the integrated concentration--of blood obtained by 24 hr continuous blood withdrawal. The fasting plasma triglyceride concentration increased significantly during ingestion of the high carbohydrate diet (P less than 0.005) but was not significantly influenced by the source of carbohydrate calories. The 45% carbohydrate diets induced larger meal associated plasma triglyceride variation than 65% diets. Sucrose-containing diets induced significantly higher plasma triglyceride integrated concentrations than corn syrup diets, whether provided as 45% (P less than 0.05) or 65% (P less than 0.005) of total energy. Diet-induced changes in fasting or integrated plasma cholesterol concentration were minimal.

Adult↗

PubMed1978

Monkey pepsinogens and pepsins. III. Carbohydrate moiety of Japanese monkey pepsinogens and the amino acid sequence around the site of its attachment to protein.

Purified Japanese monkey pepsinogens I and II contain carbohydrate as a part of the enzyme molecule. By gel filtration on Sephadex G-100, chromatography on DE-32 cellulose, and polyacrylamide disc gel electrophoresis, the carbohydrate moiety could not be separated from the enzyme protein, and the content did not decrease on repeated chromatography. Glycopeptides were obtained by successive digestion of pepsinogens with thermolysin and aminopeptidases and isolated by chromatography on Sephadex G-25 and G-50. Identification and determination of carbohydrate components was performed by paper and gas-liquid chromatographies. The presence of 4 glucosamines, 6 galactoses, 6--8 mannoses, and 8--11 fucoses per molecule of the glycopeptide of both pepsinogens was observed, of which the high content of fucose is especially unique. The molecular weight of the carbohydrate chains should be around 4,000--5,000. The amino acid sequence of a major glycopeptide was deduced to be Ile-Gly-Ile-Gly-Thr-Pro-Gln-Ala-Asn, in which the asparagine residue is the site of attachment of the carbohydrate chain.

Amino Acid Sequence↗

PubMed1975

Conversion of type III hyperlipoproteinaemia to type IV hyperlipoproteinaemia by a fat-free, carbohydrate rich diet.

Hyperlipoproteinaemia type III has been considered a clear cut clinical entity characterized by the presence of cholesterol rich "floating" beta very low density lipoproteins (VLDL) after ultracentrifugation. Carbohydrate inducibility is pronounced in type III. This study was undertaken to elucidate the effect of a high carbohydrate diet in type III as an effort to clarify a suggested association between type III and IV hyperlipoproteinaemia. On an isocaloric fat free carbohydrate rich diet the lipoprotein pattern changed as the VLDL triglycerides increased 31 per cent on average and LDL and HDL cholesterol decreased by 40 and 22 per cent. The high ratio cholesterol/triglycerides in VLDL was normalized. The lipoprotein levels in serum after carbohydrate induction showed all characteristics of a type IV with high VLDL triglycerides, normal cholesterol/triglyceride ratio in VLDL, subnormal cholesterol levels in LDL and HDL with changed relation between LDL1 and LDL2. On electrophoresis the floating beta band disappeared. It is probable that depending on the nutritional situation, the metabolic defect in type III may be expressed either as a type III or a type IV. An explanation of the effects of the carbohydrate rich diet on the lipoprotein pattern is suggested.

Cholesterol↗

PubMed1977

The role of carbohydrate in the glycoenzyme invertase of Neurospora crassa.

Data obtained concerning the carbohydrate moieties of the glycoenzyme invertase (EC 3.2.1.26, beta-D-fructofuranoside fructohydrolase) from Neurospora crassa were consistent with a linkage of some carbohydrate chains by O-glycosidic bonds to serine and threonine residues; the possibility of N-glycosylamine linkage of some of the carbohydrate to the amide group of asparagine is also indicated. The invertase was remarkably stable on storage at low temperatures. Oxidation of the carbohydrate residues in the enzyme by sodium periodate markedly affected the heat-stability of the enzyme. It is suggested that the carbohydrate moieties function as stabilizers of the tertiary structure of the glycoenzyme.

Amino Acids↗

PubMed1975

Some metabolic effects of prolonged feeding of starch, sucrose, fructose and carbohydrate-free diet in the rat.

Male rats of the ASL Wistar strain were fed from weaning on starch, fructose or carbohydrate-free diets for 4 and 12 weeks. In addition, further groups were fed for 24 weeks on starch, sucrose or carbohydrate-free diets. Livers were examined for gross composition, glucose-6-phosphatase activity and in vitro lipogenesis and glucose oxidation. Intestinal sucrase was also measured. Dietary fructose and the carbohydrate-free diet induced an enlargement of the livers after 12 weeks feeding, when expressed per 100g body weight, and at the same time, an increased fat content. Fructose caused an increase in liver glucose-6-phosphatase after 4 weeks, which persisted after 12 weeks, and a similar increase was observed after 24 weeks feeding on sucrose. Fructose produced an increase in intestinal sucrose after 4 weeks, but this did not persist and there was no increase evident after 12 weeks feeding, nor after 24 weeks feeding on sucrose. Fructose markedly depressed the in vitro lipogenesis and glucose oxidation in liver slices. This was evident after 4 weeks feeding and also after 12 weeks when the effect of age showed as a fall in both these parameters in the control group of animals. The carbohydrate-free diet caused an increase in liver glucose-6-phosphatase after 4 weeks, a smaller increase after 12 weeks, and there was no increase apparent when feeding was continued for 24 weeks. Apparently due to the absence of substrate, the intestinal sucrose activity fell to less than half after 4 weeks and to negligible levels after 12 and 24 weeks on carbohydrate-free diet. In vitro liver lipogenesis and glucose oxidation were depressed after 4 and 12 weeks in a similar way to the fructose diet. On both these diets the rise in liver glucose-6-phosphatase appeared to parallel the fall in liver lipogeneis and glucose oxidation.

Animals↗

PubMed1979

Carbohydrate of the factor VIII/von Willebrand factor in von Willebrand's disease.

We have examined the plasma Factor VIII/von Willebrand factor (FVIII/vWF) molecule from 16 patients with von Willebrand's disease, and have found no evidence of a significant decrease of carbohydrate content in 15 of these patients. FVIII/vWF was isolated by preparative counter immunoelectrophoresis directly from plasma using antibody to Factor VIII-related antigen, reduced in sodium dodecyl sulfate in the presence of urea, and electrophoresed in 5% polyacrylamide gels to separate the FVIII/vWF subunit from other proteins. Duplicate gels were stained by either the periodic acid-Schiff (PAS) reaction or by Coomassie Brilliant Blue G250. The ratio of Coomassie: PAS was determined by spectrophotometric scanning of the gels. Transferrin was used as an internal reference standard. The ratio for 23 normal individuals was 2.4+/-0.38 and the observed range was 1.8-3.8. 15 patients with von Willebrand's disease fell within this range. One patient independently reported as having decreased FVIII/vWF carbohydrate was also studied by this technique. A ratio of 6.8 was found, indicative of decreased, though not absent, carbohydrate. Cold insoluble globulin did not represent a significant contaminant in these analyses. 11 of the von Willebrand's disease patients with normal FVIII/vWF carbohydrate had abnormal crossed immunoelectrophoretic patterns characterized by absence of the less anodic forms of Factor VIII-related antigen. Four patients had normal patterns. These studies indicate that an absence or decrease of PAS reactive FVIII/vWF carbohydrate is not a consistent abnormality in von Willebrand's disease.

Blood Coagulation Factors↗

PubMed2026

Metagenomic insights into the global wild boar faecal microbiome reveal novel taxa and carbohydrate degraders distinguishing wild and domesticated Sus.

BACKGROUND: The inclusion of fibre in domestic pig diets is favourable from a digestive health, environmental, and socio-economic perspective. Unlike the highly optimized formulated diets of domestic pigs, wild boars feed opportunistically, consuming a broad range of foods that consist predominantly of plant materials. Consequently, the intestinal microbiota of wild boars is thought to be adapted to a versatile, fibre-rich diet and may represent a valuable source of probiotics for enhancing fibre degradation. However, comprehensive studies characterizing the wild boar gut microbiome, particularly its community structure and carbohydrate utilization potential, and comparison to that of domestic pigs are still lacking. RESULTS: We collected 89 faecal samples from wild boars across four countries and analysed them primarily using metagenomic sequencing. De novo assembly yielded 3,288 high- and medium-quality metagenome-assembled genomes (MAGs) representing 968 distinct species, of which 538 were previously unknown. Incorporating these MAGs enabled robust microbiome comparisons with 125 previously published samples largely from domestic pigs, which revealed significant structural and functional differences. These differences resolved into two community types, determined not by host species but by diet and lifestyle: C1 comprising 81% of samples from free-ranging, foraging wild boars and C2 consisting of 93% of samples from captive, fed domestic pigs. The lower alpha-diversity observed in C1 likely reflected the impact of highly fluctuating dietary resources and environmental conditions, resulting in dominance of fewer resilient or adaptable taxa. Nevertheless, both community types maintained substantial carbohydrate utilization potential: while C2 exhibited a higher relative abundance of CAZymesub genes associated with a broader range of carbohydrate substrate (CHO) classes, C1 was enriched in individual species that were generally richer in CAZymesub genes and CHO classes. To leverage this potential, we curated a catalogue of carbohydrate degraders from both community types and identified 47 highly versatile species, with several novel species amongst them. CONCLUSIONS: This study uncovered the previously untapped microbial diversity in the wild boar faecal microbiome and demonstrated that the faecal microbiome of Sus is primarily shaped by diet and lifestyle. The two community types identified, which differed both structurally and functionally, represent alternative states of microbiome homeostasis in wild versus domesticated Sus populations. The curated catalogue of carbohydrate degraders provides a valuable resource to guide tailored probiotic supplementation during dietary transitions to novel fibrous feedstocks. Video Abstract.

Animals↗

PubMed1978

The relations between intestinal alkaline phosphatase and carbohydrates with regard to calcium absorption.

The effect of carbohydrates on calcium absorption were studied in situ following the injection of a solution containing CaCl2 (+45Ca) into the ileal loop. The increase in Ca absorption was proportional to the concentration of carbohydrates injected and could be attributed to a progressive increase in the duration of absorption. In the ileal loop, sorbitol was much more effective than L-arabinose at equal concentrations in activating absorption. Such differences in the action of these carbohydrates were also observed in vitro with alkaline phosphatase extracted from the ileum. The transphosphorylating effect of the enzyme was much more pronounced in the case of sorbitol. Since the carbohydrate is a phosphate acceptor, it might influence the duration of absorption by reducing the inhibition exerted by phosphate upon a transfer mechanism which involves phosphatase, another possibility is that carbohydrate could postpone calcium insolubility through the formation of a phosphocarbohydrate complex.

Alkaline Phosphatase↗

PubMed1979

Carbohydrate structure of yeast invertase. Demonstration of a form with only core oligosaccharides and a form with completed polysaccharide chains.

Invertase, extracted from broken cells of Saccharomyces cerevisiae X-2180 mm2 mannan mutant, was separated into a fraction insoluble in 75% ammonium sulfate (P75 invertase, 36% carbohydrate) and a soluble fraction (S75 invertase, 53% carbohydrate). The latter reacted with antibodies specific for the alpha 1 leads to 6-linked mannose of the mannoprotein outer chain, whereas the P75 invertase failed to react with this antiserum although it did react with serum against terminal alpha 1 leads to 3-linked mannose units that are characteristic of the mannoprotein core. A bacterial endo alpha 1 leads to 6-mannanase removed the outer chains from the S75 invertase and converted it to a form that was similar in electrophoretic and immunochemical properties to the P75 invertase, whereas the endomannanase had little effect on the latter invertase. The results suggest that the P75 invertase is a form of the enzyme to which only the core oligosaccharide units had been added, and the S75 invertase represents an enzyme fraction to which the polysaccharide outer chains were also attached. A strong anomeric PMR signal for unsubstituted alpha 1 leads to 6-linked mannose in the S75 invertase, and a much reduced signal in the P75 invertase and endomannanase-digested S75 invertase, support these conclusions. Endo-N-acetyl-beta-glucosaminidase digestion of the S75 and P75 invertases, as well as of a purified wild type yeast invertase, produced an apparently identical series of 3 to 4 carbohydrate-containing proteins that were separable by polyacrylamide gel electrophoresis in sodium dodecyl sulfate but that migrated as a single band on isoelectric focusing. The bands ranged from about 63,000 to 69,000 daltons and differed by the size of one or more carbohydrate core units each of 15 mannoses and 1 N-acetylglucosamine. The results suggest that the external invertase molecules contain some core units without attached outer chains, and that the cells contain a precursor form of the enzyme to which only the core units have been added. In support of this conclusion, PMR spectra and chromatographic patterns show that the core fragments from the P75, S75, and wild type invertases are essentially identical.

Carbohydrate Conformation↗