The chemical composition of the cyst wall of the potato cyst-nematode, Heterodera rostochiensis

1. Cyst walls of the potato cyst-nematode (Heterodera rostochiensis Woll.) were isolated by sieving a suspension of crushed cysts. About 12mg. of dried cyst walls was obtained from 1000 cysts. 2. The cyst walls contained mainly protein (72%, calculated from nitrogen content). On acid hydrolysis about 77% of the cyst wall went into solution. Of 19 amino acids present, proline, glycine, and alanine were the most abundant, and made up about 50% by weight of the total amino acids. The amino acid composition suggested that collagen-like proteins predominated in the cyst wall and larval cuticle. 3. A small amount of glucosamine (1.5%) was present in the hydrolysates, but chitin was not detected in the cyst walls. 4. Other components of the cyst walls were lipid (2%), carbohydrate (0.5%) and a small amount of inorganic matter (ash, 5%). Polyphenols (2% by wt. of the cyst walls) occurred in the acid hydrolysates. The dark pigments of the cyst wall were not indole-containing melanins.     

The structure of a glycopeptide isolated from the yeast cell wall

1. Glycopeptides containing mannose were extracted from isolated yeast cell walls by ethylenediamine and purified by treatment with Pronase and fractionation on a Sephadex column. 2. A glycopeptide that appeared homogeneous on electrophoresis and ultracentrifugation had a molecular weight of 76000, and contained a high-molecular-weight mannan and approx. 4% of amino acids. 3. The amino acid composition of the peptide was determined. It was rich in serine and threonine and also contained glucosamine. No cystine and methionine were detected. 4. The glycopeptide underwent a beta-elimination reaction when treated with dilute alkali at low temperatures. The reaction resulted in the release of mannose, mannose disaccharides and possibly other low-molecular-weight mannose oligosaccharides. During the beta-elimination reaction the dehydro derivatives of serine and threonine were formed. One of the linkages between carbohydrate and amino acids in the glycopeptide is an O-mannosyl bond from mannose and mannose oligosaccharides to serine and threonine. 5. After the beta-elimination reaction the bulk of the mannose in the form of the large mannan component was still covalently linked to the peptide. This polysaccharide was therefore attached to the amino acids by a linkage different from the O-mannosyl bonds to serine and threonine that attach the low-molecular-weight sugars. 6. Mannan was prepared from the glycopeptide and from the yeast cell wall by treatment of the fractions with hot solutions of alkali. The mannan contained aspartic acid and glucosamine and some other amino acids. The aspartic acid and glucosamine were present in equimolar amounts; the aspartic acid was the only amino acid present in an amount equivalent to that of glucosamine. Thus there is the possibility of a linkage between the mannan and the peptide via glucosamine and aspartic acid. 7. Mannose 6-phosphate was shown to be part of the mannan structure. Information about the structure of the mannan and the linkage of the glucosamine was obtained by periodate oxidation studies. 8. The glucosamine present in the glycopeptide could not be released by treatment with an enzyme preparation obtained from the gut of Helix pomatia. This enzyme released glucosamine from the intact cell wall. Thus there are probably at least two polymers containing glucosamine in the cell wall. 9. The biosynthesis of the mannan polymer in the yeast cell wall is discussed with regard to the two types of carbohydrate-amino acid linkages found in the glycoprotein.     

Electrophoretic isolation and partial characterization of a major secretory glycoprotein from the submandibular glands of the mouse

After either cholinergic or adrenergic stimulation of the submandibular glands of the mouse, a major protein of the incubation medium could be isolated by electrophoresis, designated the AM2 protein. About 5 per cent of the secreted proteins and 2.4 per cent of the secreted protein-bound sialic acid was recovered as the purified AM2 protein. The AM2 protein appeared to be electrophoretically pure in 7.5% polyacrylamide gel both at pH 8.9 and at pH 4.3. In sodium dodecyl sulfate-electrophoresis the molecular weight was estimated to be about 80 000 for the major component and about 40 000 for the minor component. By isoelectric focusing the isoelectric point has been determined to be 4.7. The amino acid analysis indicated Glx, Asx, Leu and Ala as the major amino acids, comprising 15.0, 10.6, 9.2 and 9.1 per cent of the amino acid residues, respectively. The ratio of the acidic amino acids and their amides (Glx plus Asx) to the basic amino acids (Lys plus Arg) was 2.2. The sugar analysis showed that the AM2 glycoprotein consists of 17.3 per cent of carbohydrate, with as major carbohydrate component glucosamine. The molar ratio of the sugars was Man : Gal : Glc : GlcNH2 : sialic acid = 2.3 : 1.0 : 4.7 : 9.8 : 2.9. Galactosamine could be detected as a trace component and fucose was not detectable.     

Concurrent protein synthesis is required for in vivo chitin synthesis in postmolt blue crabs

Chitin synthesis in crustaceans involves the deposition of a protein-polysaccharide complex at the apical surface of epithelial cells which secrete the cuticle or exoskeleton. The present study involves an examination of in vivo incorporation of radiolabeled amino acids and amino sugars into the cuticle of postmolt blue crabs, Callinectes sapidus. Rates of incorporation of both 3H leucine and 3H threonine were linear with respect to time of incubation. Incorporation of 3H threonine into the endocuticle was inhibited greater than 90% in the presence of the protein synthesis inhibitor, puromycin. Linear incorporation of 14C glucosamine into the cuticle was also demonstrated; a significant improvement of radiolabeling was achieved by using 14C-N-acetylglucosamine as the labeled precursor. Incorporation of 3H-N-acetylglucosamine into the cuticle of postmolt blue crabs was inhibited 89% by puromycin, indicating that concurrent protein synthesis is required for the deposition of chitin in the blue crab. Autoradiographic analysis of control vs. puromycin-treated crabs indicates that puromycin totally blocks labeling of the new endocuticle with 3H glucosamine. These results are consistent with the notion that crustacean chitin is synthesized as a protein-polysaccharide complex. Analysis of the postmolt and intermolt blue crab cuticle indicates that the exoskeleton contains about 60% protein and 40% chitin. The predominant amino acids are arginine, glutamic acid, alanine, aspartic acid, and threonine.     

Protein-polysaccharides of pig laryngeal cartilage

1. Protein-polysaccharides of chondroitin 4-sulphate were extracted with neutral calcium chloride from pig laryngeal cartilage that was not completely homogenized. The protein-polysaccharides were purified by precipitation with 9-aminoacridine. On zone electrophoresis in compressed glass fibre at pH7.2 it was separated into two fractions, although two distinct zones were not obtained. These fractions, which had already been shown to differ in their antigenic determinants, also differed considerably in amino acid composition, total protein, hexose and glucosamine contents. 2. The fraction of higher mobility contained approx. 2% of protein and only traces of glucosamine. Serine and glycine accounted for over half the total amino acid residues, but aromatic, basic and sulphur-containing amino acids were not detected. The weight-average molecular weight, determined by sedimentation, was 230000. 3. Assuming that there was the same sequence of neutral sugars at the linkage points as in PP-L fraction (protein-polysaccharide light fraction), the approximate molar ratio of hexose to serine suggested that most of the serine residues were linked to chondroitin sulphate chains. Support for this was derived from the agreement between the weight-average molecular weight of the chondroitin sulphate-peptide after proteolysis, and the chain weight calculated from its serine content. The chain weight based on the serine content of the fraction of higher electrophoretic mobility was approximately similar. 4. In contrast, the fraction of lower electrophoretic mobility resembled PP-L fraction in its amino acid composition, protein and glucosamine contents. The presence of glucosamine, together with the higher hexose content, suggested that this fraction contained some keratan sulphate. 5. The relatively low molecular weight of the fraction of higher mobility enabled it to be extracted without complete disintegration of the cartilage. The unlikelihood of its being produced by autolytic enzymes is discussed.     

The composition of the cyst wall of the beet cyst-nematode Heterodera schachtii

1. Cyst walls of the beet cyst-nematode (Heterodera schachtii Schmidt) were obtained by sieving a suspension of crushed cysts; about 15mg of dried cyst walls was obtained from 1000 cysts. 2. The cyst walls contained 68% protein calculated from nitrogen content. Glutamic acid, glycine, proline and hydroxyproline made up about 54% by weight of the amino acids obtained on acid hydrolysis. 3. Minor constituents of the cyst wall were hexosamine (3.3%), lipid (6%), carbohydrate (2%) and phenols (2%). The hexosamine was identified as galactosamine. 4. The cyst walls contained inorganic material (ash 17%), most of which was extractable with EDTA, but not with water. Major inorganic components were calcium and phosphorus (1.7% and 1.5% respectively, by weight). Carbon dioxide (about 1% by weight) was liberated from the cyst walls on acidification. 5. The cyst walls of H. schachtii and the potato cyst-nematode (Heterodera rostochiensis) contained different amounts of the same amino acids. They also differed in their inorganic content and in the nature of the hexosamine present.     

Characterization of a glycoprotein in the cyst fluid of Cysticercus tenuicollis from the goat

Dixon S. N., Gibbons R., Parker Janice and Sellwood R. 1973. Characterization of a glycoprotein in the cyst fluid of Cysticercus tenuicollis from the goat. International Journal for Parasitology3:419–424. In the fluids of two tapeworm cysts from goats a prominent periodic acid- Schiff reagent staining protein was found on gel electrophoretograms. In one case serum proteins from the host were also observed. The glycoprotein has been isolated and found to contain about 7·7 per cent heterosaccharide consisting of glucose, galactose, mannose, fucose, neuraminic acid, glucosamine and an unidentified component. The amino acid portion is extremely rich in glutamic acid, aspartic acid, lysine and arginine. Its molecular weight is approximately 90,000. A small degree of heterogeneity was demonstrated by ultra-centrifugal analysis; this may be due to the presence of about 3 per cent of a glycosaminoglycan. In view of the high proportion of charged amino acids it is suggested that this glycoprotein, which appears to be derived from the parasite, functions as the osmotically active macromolecule in the cyst fluid maintaining the turgidity of the cyst.     

Cell wall composition in the ascomycete sphaerostilbe repens at different developmental stages

Changes in the biochemical composition of isolated cell walls were analysed during the differentiation of coremia and rhizomorphs in Sphaerostilbe repens.Differentiation was accompanied by exclusively quantitative variations of the wall components: the content in carbohydrates, chitin and free amino sugars increased; on the contrary, amino acids, uronic acids, lipids and mineral substances decreased.Carbohydrates were composed of glucose, galactose and mannose; glucosamine was the main component of amino sugars. The predominant amino acid in the walls was cysteine the amount of which increased during hyphal aggregation, while quantities of the sixteen other determined amino acids decreased.Mineral matter was present in large quantities in the walls of the fungus, especially in vegetative mycelium. Iron, phosphorus and calcium were the most abundant elements.Possible relations between the variations in chemical composition of the wall and the capability of hyphae to aggregate are discussed.     

Changes in glucosamine and galactosamine levels during conidial germination in Neurospora crassa.

The levels of glucosamine and galactosamine were determined in conidia, germinating conidia, and vegetative mycelia of Neurospora crassa. In the vegetative mycelia about 90% of the amino sugars were shown to be components of the cell wall. The remaining 10% of the amino sugars were tentatively identified as the nucleotide sugars uridine diphospho-2-acetamido-2-deoxy-D-glucose and uridine diphospho-2-acetamido-2-deoxy-D-galactose. Conidia and vegetative mycelia contained about the same levels of glucosamine. During the first 9 h after the initiation of germination, the total glucosamine content had increased 3.1-fold, whereas the residual dry weight of the culture had increased 7.7-fold. This led to a drop in the glucosamine concentration from 100 mumol/g of residual dry weight to 42 mumol/g. During this time, all of the conidia had germinated and the surface area of the new germ tubes had increased to 10 times that of the conidia. Either germ tubes were initially produced without glucosamine-containing polymers, or these polymers (probably chitin) were deposited only at low densities in the germ tube cell walls. The chitin precursor uridine diphospho-2-acetamido-2-deoxy-D-glucose was present at all times during conidial germination. Conida contained very low levels of galactosamine. During germination, galactosamine could not be detected until the culture had reached a cell density of about 0.6 mg of residual dry weight per ml of growth medium. This was observed regardless of the time required to reach this cell density or the fold increase in dry weight. The accumulation of galactosamine-containing polymers does not appear to be necessary for germ tube formation. The levels of soluble galactosamine (uridine diphospho-2-actamido-2-deoxy-D-galatose) were very low in conidia and increased during germination at the same time that galactosamine appeared in the cellular polymers. In addition, under certain culture conditions, the appearance of galactosamine and the increase in the glucosamine concentration occurred simultaneously.     

Agglutinin from Limulus polyphemus. Purification with formalinized horse erythrocytes as the affinity adsorbent.

We have purified an agglutinin from the hemolymph of Limulus polyphemus about 1500-3000-fold by adsorption to formalinized horse erythrocytes, elution with N-acetylneuraminic acid and subsequent fractionation on Sephadex G-200. Recovery was in the range of 50 percent. On ultracentrifugation the agglutinin behaves as an homogenous protein with a molecular weight of about 460 000. On polyacrylamide gel electrophoresis of the dissociated protein in sodium dodecylsulfate we found a single prominent diffuse band with an apparent molecular weight of 22 000 plus or minus 2000. This band contained carbohydrate as determined by periodic acid-Schiff staining. The intensity of staining compared with standards suggested a carbohydrate content of less than 4 percent. The protein contains a preponderance of acidic amino acids and has an isoelectric point of 4.83.5 residues per 1000 of glucosamine were detected on amino acid analysis. Agglutination of formalinized horse erythrocytes by the purified protein is inhibited not only by N-acetylneuraminic acid but also by D-glucuronic acid; but not by a number of other monosaccharides. D-Glucuronic acid may be used in place of N-acetylneuraminic acid as the eluting sugar in the purification procedure.     

Chemical Composition of the Cell Wall of the H37Ra Strain of Mycobacterium tuberculosis

The cell wall of the H37Ra strain of Mycobacterium tuberculosis was isolated and freed of extraneous noncovalently linked material by a series of extraction and enzymatic procedures. Chemical analysis of the cell wall has revealed the following composition: 22.8% amino acids, principally alanine, glutamate, and diaminopimelate in a molar ratio of 1:1.8:0.8; 24.7% reducing sugars, all in the form of arabinose and galactose in a molar ratio of 2.6:1; and 3.95% amino sugars, all in the form of glucosamine, muramic acid, and galactosamine in a molar ratio of 1:6.6:0.8. About 32.1% of the dry weight of the cell wall is lipid, of this about 55% is in the form of two series of mycolic acids. Each series of mycolic acids contains two homologues differing by 28 mass units. One pair of homologues contains in each a carbonyl function and an unsaturated double bond; the other pair contains two cyclopropane groups in each homologue. The remaining lipids are composed principally of normal saturated fatty acids, including tuberculostearic acid.     

Preparation and Chemical Composition of the Cell Walls of Mature Infectious Dense Forms of Meningopneumonitis Organisms

Relatively large-scale production and purification of meningopneumonitis organisms was developed for chemical and immunological studies on cell walls of the infectious dense forms. By disruption of purified organisms with glass beads in a Mickle shaker, highly purified preparations of cell walls were obtained by sucrose density gradient centrifugation, enzyme digestion, and sodium dodecyl sulfate treatment. The dry-weight recovery of purified cell walls from intact organisms was about 13%. When (32)P-labeled preparations of cell walls were fractionated into acid-soluble, lipid, ribonucleic acid (RNA), deoxyribonucleic (DNA), and residual fractions, about 80% of the (32)P in cell wall preparations was recovered in the phospholipid fraction, which corresponded to about 3% of the total phospholipid in the intact organisms. About 7% of the (32)P in purified cell walls was recovered in the RNA and DNA fractions respectively, but this corresponds to only about 0.4% of the (32)P found in those fractions in intact organisms. From dry-weight determinations, it was calculated that the purified cell wall preparations contained only 0.6% total nucleic acids, and these are probably not true cell wall constituents. These cell walls contained 70 to 75% protein, corresponding to about 14% of the protein in intact organisms. Amino acid analysis of these protein showed the existence of all common amino acids, glucosamine, and galactosamine. However, no muramic acid was detected by the methods employed.     

The hypobranchial mucin of the whelk Buccinum undatum L. Properties of the mucin and of the glycoprotein component

1. The composition of the hypobranchial mucin from Buccinum undatum is reported. 2. The amino acid composition was determined; aspartic acid and glutamic acid contribute almost 24% of the total amino acids in the mucin. 3. Serine, threonine and alanine, in the proportions 2:1:1 respectively, were detected as N-terminal residues, implying the presence of at least four protein chains. 4. A glycoprotein component was isolated by phenol precipitation. 5. The glycoprotein contained 8% of neutral sugars comprising glucose, galactose, mannose and fucose, and 4.5% of hexosamine, comprising glucosamine and galactosamine in equal proportions. 6. A method is described for the preparation of glycopeptides from the glycoprotein. 7. The comparative biochemistry of the mucin is discussed.     

NUTRITIONAL VALUE OF THE FIELD CRICKET (GRYLLUS TESTACEUS WALKER)

Abstract The chemical composition and the nutritional quality of protein, fatty acids and chitin of adult field cricket Gryllus testaceus Walker were investigated. The adult insect contained: crude protein 58.3 %; fat 10.3 %, chitin 8.7 % and ash 2.96 % on dry matter basis respectively. The essential amino acid profile compared well with FAO/WHO recommended pattern except for cysteine and methionine. The fatty acid analysis showed unsaturated acid of the field cricket to be present in high quantities, and the total percentage of oleic acid, linolic acid and linolenic acid was 77.51%. The chitin content of the insect was 8.7% with a better quality than the commercial chitin that was prepared from shells of shrimp and crab. Therefore the chemical composition of the field cricket indicates the insect to be a good supplement to nutrition for food and feed, even a raw material for medicine.     

油葫芦的营养价值(英文)

本研究旨在确定油葫芦Gryllus testaceus Walker的主要营养成分和营养价值。研究发现油葫芦体内主要含有蛋白质、脂类和几丁质三类物质,它们的含量(干重比)分别是58.3％,10.3％和8.7％。其中必需氨基酸的含量除了半胱氨酸和蛋氨酸外,非常符合FAO／WHO所确定的人体对氨基酸需求标准。脂肪酸分析显示,不饱和脂肪酸的含量很高,仅油酸、亚油酸和亚麻酸的含量就占总脂肪含量的77.51％。油葫芦的甲壳素含量为8.7％,而且从该虫提取甲壳素／壳聚糖的品质在甲壳素色泽及残留灰分含量、壳聚糖粘度等方面比常规甲壳素原料虾蟹壳的好。因此,油葫芦可以作为很好的食品或饲料添加剂,或医药原料。     

皱肋文蛤氨基酸含量及脂肪酸组成分析

测定了皱肋文蛤(Meretrix lyrata)软体部分的氨基酸含量与脂肪酸组成.共检出17种氨基酸,总含量为软体部干重的52.26%;4种呈味氨基酸(天门冬氨酸、谷氨酸、甘氨酸和丙氨酸)的含量为22.07%,占氨基酸总量的42.23%;必需氨基酸(EAA)总含量为20.72%,其必需氨基酸的构成比例基本符合FAO/W...     

Rapid modulation of the n-3 docosahexaenoic acid levels in the brain and retina of the newly hatched chick

The newly hatched chick obtains its fatty acids almost completely from the lipids of the egg yolk as these are transferred to the developing embryo during its 21-day period of incubation. Since the diet of the laying hen greatly influences the fatty acid composition of the egg lipids, and presumably also the fatty acid composition of the resulting chick, we tested how quickly and to what extent varying the amount of n-3 fatty acids in the diet of the hen would modulate the level of n-3 fatty acids in the brain and retina of the newly hatched chick. White Leghorn hens were fed commercial or semi-purified diets supplemented with 10% fish oil, linseed oil, soy oil, or safflower oil. Eggs, together with the brain, retina, and serum of newly hatched chicks, were then analyzed for fatty acid composition. The fatty acids of egg yolk responded quickly to the hen's diet with most of the change occurring by 4 weeks. There was a linear relationship between the linolenic acid content of the diets and levels of this fatty acid in egg yolk and chick serum. In chicks from hens fed the fish oil diet, the total n-3 fatty acids, including 22:6(n-3), were elevated twofold in the brain and retina and sevenfold in serum relative to commercial diet controls. The safflower oil diet led to a very low n-3 fatty acid content in egg yolks and only 25% of the control n-3 fatty acid content in the brain and retina of chicks.(ABSTRACT TRUNCATED AT 250 WORDS)     

摩鹿加云斑蛛卵袋结构与纤维组成

采用扫描电子显微镜（SEM）和氨基酸自动分析仪对摩鹿加云斑蛛Cyrtophora moluccensis卵袋的结构和组成进行了观察研究.结果表明摩鹿加云斑蛛的卵袋呈椭球状,是由多种丝腺纺出的微米与纳米级的丝纤维形成的多个覆盖层构成的,包括白色框架、军绿色与灰白色外覆盖层和白色内覆盖层3部分.卵袋框丝与典型的拖牵丝氨酸组成基本相似,丙氨酸和甘氨酸的含量最丰富,分别约占39%和33%,其次是谷氨酸、丝氨酸和脯氨酸,分别约占7.8%、5.7%和3.6%;其余卵袋丝纤维的氨基酸组成与典型的柱状腺丝相似,与卵袋框丝相比,卵袋覆盖层的丝氨基酸的含量显著增加,约占21%,同时甘氨酸和脯氨酸的含量显著减少,分别约占12%和1%,并含有更多的极性和大侧链氨基酸,其丙氨酸的含量变化不大,仍占了27%左右.根据氨基酸组成与扫描电镜的结果综合分析了不同自径丝纤维的丝腺来源.     

A chitin-like component in Aedes aegypti eggshells, eggs and ovaries

An insoluble white substance was prepared from extracts of eggshells of Aedes aegypti, the yellow fever mosquito and dengue vector. Its infrared and proton NMR spectra were similar to that of standard commercial chitin. This putative chitin-like material, also obtained from ovaries, newly laid and dark eggs, was hydrolyzed in acid and a major product was identified by HPLC to be glucosamine. The eggshell acid hydrolysate was also analyzed by ESI-MS and an ion identical to a glucosamine monoprotonated species was detected. The presence of chitin was also analyzed during different developmental stages of the ovary using a fluorescent microscopy technique and probes specific for chitin. The results showed that a chitin-like material accumulates in oocytes during oogenesis. Streptomyces griseus chitinase pre-treatment of oocytes greatly reduced the chitin-derived fluorescence. Chitinase activity was detected in newborn larvae and eggs prior to hatching. Feeding experiments indicated that the chitin synthesis inhibitor lufenuron inhibited chitin synthesis, either when mosquitoes were allowed to feed directly on lufenuron-treated chickens or when an artificial feeding system was used. Lufenuron inhibited egg hatch, larval development and reduced mosquito viability. These data demonstrate for the first time that (1) a chitin-like material is present in A. aegypti eggs, ovaries and eggshells; (2) a chitin synthesis inhibitor can be used to inhibit mosquito oogenesis; and (3) chitin synthesis inhibitors have potential for controlling mosquito populations.     

鸡粪中氨基酸含量测定与开发利用

本文对蛋鸡饲料与鸡粪进行了１３次１６种氨基酸含量的测定分析,氨基酸含量稳定,鸡粪中氨基酸含量比常用的部分饲料中氨基酸含量高。鸡对饲料中蛋白质的利用率仅为２９％;大部分蛋白质仍在鸡粪中,从分析结果看,１００克鸡粪中含有各种氨基酸１０．４５克。鸡粪取材广泛,价格低廉,氨基酸便于提取,有广阔的开发利用前景。