Brachyptera Group. Sp.32. C. Brachyptera. Sp.33. C.c RUFA. Sp.34. C. Troglodytes. Sp.35. C. Fulvicapilla.

A part from considerations as to where it is best wedged into the linear sequence, the brachyptera group is defined in general terms as a compact group of four small or very small species which resemble one another in many important specific characters and the other thirty-six species classified here as Cisticola in so many ways of form, coloration and behaviour as to make them best understood by classifying them also under that generic name.     

The glycolipids of Lactobacillus casei A.T.C.C. 7469

1. The lipids were extracted from Lactobacillus casei A.T.C.C. 7469 with chloroform-methanol mixtures. The glycolipids were obtained by chromatography on silicic acid and DEAE-cellulose (acetate form). 2. Hydrolysis of the glycolipids with alkali gave two glycerol glycosides and a mixture of fatty acids. 3. The glycosides were separated and their structures elucidated. The major component was O-alpha-d-galactopyranosyl-(1-->2)-O-alpha-d-glucopyranosyl-(1-->1)-glycerol and the minor component O-alpha-d-glucopyranosyl-(1-->6)-O-alpha-d-galactopyranosyl-(1-->2)-O-alpha-d-glucopyranosyl-(1-->1)-glycerol. 4. Analysis of the fatty acids by gas-liquid chromatography showed that they were predominantly palmitic acid, octadecenoic acid and lactobacillic acid.     

Counterions which favour the C form of DNA.

Recently the relationship between the B and C forms of DNA has been questioned. We have found some amino acids and related amines which form complexes with DNA and favour the C form. We have studied such complexes by X-ray diffraction. With some of these counterions the transition between the B and C forms occurs smoothly, whereas in other cases there is a discontinuous transition. We conclude that the C form is a well-defined variant of the B form favoured by some counterions under low humidity conditions.     

A.T and C.C+ base pairs can form simultaneously in a novel multistranded DNA complex

Previous experiments have established that in certain synthetic oligomeric DNA sequences, including mixtures of d(AACC)5 with d(CCTT)5, adenine-thymine (A.T) base pairs form to the exclusion of neighboring protonated cytosine-cytosine (C.C+) base pairs [Edwards, E., Ratliff, R., & Gray, D. (1988) Biochemistry 27, 5166-5174]. In the present work, circular dichroism and other measurements were used to study DNA oligomers that represented two additional classes with respect to the formation of A.T and/or C.C+ base pairs. (1) One class included two sets of repeating pentameric DNA sequences, d(CCAAT)3-6 and d(AATCC)4,5. For both of these sets of oligomers, an increase in the magnitude of the long-wavelength positive CD band centered at about 280 nm occurred as the pH was lowered from 7 to 5 at 0.1 and 0.5 M Na+, indicating that C.C+ base pairs formed. Even though it may have been possible for these oligomers to form duplexes with two antiparallel A.T base pairs per pentamer, no A.T base pairing was detected by monitoring the CD changes at 250 nm. Thus, spectral data showed that as few as 40% C.C+ base pairs were stable in two sets of oligomers in which A.T base pairs did not form adjacent to, or in place of, C.C+ base pairs. (2) Another class of oligomer was represented by d(C4A4T4C4), which was studied by CD, HPLC, and centrifugation experiments. We confirmed previous work that this sequence was able to form both types of base pairs as the pH and temperature were lowered [Gray, D., Cui, T., & Ratliff, R. (1984) Nucleic Acids Res. 12, 7565-7580].(ABSTRACT TRUNCATED AT 250 WORDS)     

The separation of bovine brain beta-N-acetyl-D-hexosaminidases. Abnormal gel-filtration behaviour of beta-N-acetyl-D-glucosaminidase C.

Bovine brain tissue was extracted and the 50 000g supernatant was separated by electrophoresis, DEAE-Sephadex chromatography and gel filtration on Sephadex G-200 and Bio-Gel P-200. The electrophoretic separation showed that the beta-N-acetyl-D-hexosaminidases (hexosaminidases) of bovine brain tissue were composed of four different fractions. Two fractions (A and B) exerted both glucosaminidase and galactosaminidase activity, a third fraction (C) showed only glucosaminidase activity, whereas a fourth form (D) with specificity towards the galactosaminide moiety was found to be present. DEAE-Sephadex chromatography at pH 7.0 showed that the B form was eluted with the void volume, whereas the A and D forms could be eluted in one peak by raising that salt concentration. The C form could not be detected in the eluate. Gel filtration on Sephadex G-200 showed that the B, A and D forms had almost equal molecular weights. In this case also the C form could not be detected in the column eluates. Gel filtration on Bio-Gel P-200 revealed that the C form was eluted with the void volume.     

Preparation and characterization of troponin C from bullfrog skeletal muscle.

Troponin C was isolated from the skeletal muscle of bullfrog (Rana catesbeiana), and its relative molecular mass was estimated to be 18,000 by SDS/polyacrylamide gel electrophoresis. In its amino acid composition, bullfrog troponin C was similar to that of the frog (Rana esculenta) but different from that of rabbit. Its ultraviolet spectrum was consistent with its amino acid composition. The ultraviolet difference spectrum of the Ca(2+)-loaded form vs. the metal-free form indicated that the single Tyr residue and some Phe residues in the bullfrog troponin C molecule were affected by the conformational change associated with Ca2+ binding. On electrophoresis in polyacrylamide gel in 14 mM Tris and 90 mM glycine, the metal-free and Mg(2+)-loaded forms migrated slower than the Ca(2+)-loaded form. The property is shared by rabbit troponin C but not parvalbumins or calmodulin. The ATPase activity of CDTA-treated myofibrils reconstituted with bullfrog troponin C showed the same Ca(2+)- and Sr(2+)-sensitivity as that of those reconstituted with rabbit troponin C. Bullfrog troponin C is, thus, physiologically the same as rabbit troponin C, in spite of several marked differences in their physicochemical properties.     

Pepsinogen C and pepsin C from gastric mucosa of Japanese monkey. Purification and characterization.

A new pepsinogen component, pepsinogen C, was purified from the gastric mucosa of Japanese monkey. The chromatographic behavior of this component on DE-32 cellulose was coincident with that of pepsinogen III-2 previously reported (1), and final purification was performed by large-scale polyacrylamide disc gel electrophoresis. The molecular weight was 35,000 as determined by gel filtration. The ratios of glutamic acid to aspartic acid and of leucine to isoleucine were higher than those of other Japanese monkey pepsinogens. The activated form, pepsin C, had a molecular weight of 27,000 and contained a large number of glutamic acid residues. The optimal pH for hemoglobin digestion was 3.0. Pepsin C could scarcely hydrolyze the synthetic substrate, N-acetyl-L-phenylalanyl-3, 5-diiodo-L-tyrosine (APDT). 1, 2-Epoxy-3-(p-nitrophenoxy)propane (EPNP), p-bromophenacyl bromide, and diazoacetyl-DL-norleucine methyl ester (DAN) inhibited pepsin C [EC 3.4.23.3] in the same way as pepsin III-3 of Japanese monkey. The susceptibility to pepstatin of pepsin C was lower than that of pepsin III-3, and 500 times more pepstatin was required for the same inhibitory effect. The classification and nomenclature of Japanese monkey pepsinogens and pepsins are discussed.     

Structural prediction and analysis of endothelial cell protein C/activated protein C receptor.

The endothelial cell receptor (EPCR) for protein C (PC)/activated protein C (APC) is a 221 amino-acid residues long transmembrane glycoprotein with unclear physiological function. To facilitate future studies and to rationalize recently reported experimental data about this protein, we have constructed three-dimensional models of human, bovine and mouse EPCR using threading and comparative model building. EPCR is homologous to CD1/MHC class I molecules. It consists of two domains, which are similar to the alpha1 and alpha2 domains of MHC class I molecules, whereas the alpha3 domain of MHC is replaced in EPCR by a transmembrane region followed by a short cytosolic tail. The alpha1 and alpha2 domains of CD1/MHC proteins form a groove, which binds short peptides. These domains are composed of an eight-stranded antiparallel beta-pleated sheet with two long antiparallel alpha-helices. The distance between the helical segments dictates the width of the groove. The cleft in EPCR appears to be relatively narrow and it is lined with hydrophobic/aromatic and polar residues with a few charged amino acids. Analysis of the human EPCR model predicts that (a) the protein does not contain any calcium binding pockets; (b) C101 and C169 form a buried disulphide bridge, while C97 is free, and buried in the core of the molecule; and (c) four potential glycosylation sites are solvent exposed.     

Binding of fluid-phase complement components C3 and C3b to human lymphocytes.

It is known that a population of B-lymphocytes has receptors for the third component of complement, C3, and that these lymphocytes may be identified by their ability to form rosettes with sheep erythrocytes coated with covalently bound fragments of complement component C3. Human tonsil lymphocytes, enriched for B-cells, form rosettes with sheep erythrocytes coated with antibody and complement components C1, C4b and C3b (EAC143b cells). Fluid-phase C3 will inhibit rosette formation between EAC143b and human tonsil lymphocytes over the same concentration range as fluid-phase C3b. C3 is not cleaved to C3b during incubation with lymphocytes or with lymphocytes and EAC143b cells. Fluid-phase 125I-labelled C3 and 125I-labelled C3b bind to lymphocytes in a specific manner. The characteristics of binding of both radioiodinated C3 and radioiodinated C3b are very similar, but the binding oc C3 is again not a result of cleavage to C3b. Salicylhydroxamic acid does not inhibit binding of 125I-labelled C3 to tonsil lymphocytes at concentrations that completely inhibit binding of 125I-labelled C3 to EAC142 cells via the nascent binding site of C3b. It is concluded that C3 and C3b share a common feature involved in binding to lymphocytes bearing receptors for the third component of complement.     

X-ray and 13C solid-state NMR studies of N-benzoyl-phenylalanine.

A crystalline sample of N-benzoyl-DL-phenylalanine 1 and a polycrystalline sample of N-benzoyl-L-phenylalanine 2 were studied using 13C high-resolution solid-state NMR spectroscopy. The X-ray structure of the DL form was established. Sample 1 crystallizes in a monoclinic form with a P21/c space group, a=11.338(1) A, b=9.185(1) A, c=14.096(2) A, beta=107.53(3) degrees, V=1400(3) A3, Z=4 and R=0.053. The principal elements of the 13C chemical shift tensors deltaii for 1 and 2, selectively 13C (99%) labeled at the carboxyl groups were calculated. On the basis of 13C (delta)ii analysis the hydrogen bonding pattern for sample 2 was deduced. Enriched samples were used to establish the intermolecular distance between chemically equivalent nuclei for 1 and spatial proximity in heterogeneous domain for 2, employing the ODESSA pulse sequence. The consistence of the complementary approach covering X-ray data, analysis of the 13C (delta)ii parameters and ODESSA results is revealed.     

Cytogenetic studies in Cochlearia L. (Cruciferae). The origins of C. officinalis L. and C. micacea Marshall

Genome analysis has been used to investigate the evolutionary relationships of the tetraploid species in the genus Cochlearia. The results indicate that both C. officinalis L. (2n=24) and C. micacea Marshal (2n=26) are essentially autotetraploid in origin and that C. scotica Druce is simply a morphological variant of C. officinalis. The chromosomal relationships of the tetraploids to each other and to the diploids in the genus are discussed and the possible routes for the formation of all the species from a single, 2n=12, basic taxon are given. Evidence for the existence of a genic mechanism causing C. officinalis to form only bivalents is given and the mode of evolution of such a mechanism discussed.     

First determination of the isozyme patterns of phosphoglycerate mutases (E.C.2.7.5.3) and phosphoglycerate kinases (E.C.2.7.2.3) in human tissues.

We present in this paper the first report about identification of several fractions of phosphoglycerate mutase (PGlyM) activity using starch gel electrophoresis and two different buffer systems. A typical muscle form of PGlyM was detected. It is also shown that isozymes of phosphoglycerate kinase (PGK) can be separated through the buffer system used by Spencer et al; (1964) for the phosphogluco mutase.     

Response of Clostridium perfringens and its L form to bacteriocins of C. perfringens

Clostridium perfringens strain No. 28 and its penicillin-induced stable L form were treated with 10 different bacteriocins of C. perfringens. Viable count and labelled amino acid incorporation experiments revealed that the L form was sensitive to two and possibly three bacteriocins to which the bacillus was not, while both forms were commonly sensitive to two other bacteriocins and resistant to five others. Adsorption of bacteriocin, immunity factors, or perhaps uptake of bacteriocin might be proposed to explain the responses of these organisms to bacteriocins.     

Separation of the filamentous and cellular yeast forms of C. albicans following serum induction

Following serum induction of filamentous structures in Candida albicans, the budding and filamentous forms of the organism are separated and the total protein in each form is determined. The method is useful for testing potential chemotherapeutics aimed at interference with the formation of the pathogenic, filamentous form of C. albicans.     

The lipids C2- and C16-ceramide form large stable channels. Implications for apoptosis

We report that physiological concentrations of both short- and long-chain ceramides, despite being lipids, form large stable pores in membranes. Some of these pores should be large enough to allow cytochrome c to permeate. Dihydroceramide differs from ceramide by the reduction of one double bond, and yet both its apoptogenic and channel-forming activities are greatly reduced. A structural model provides insight into how ceramides might form pores. According to a mathematical model, both the individual conductance of the channels and the overall membrane conductance are directly related to the overall concentration of ceramide in the membrane. Slight changes in concentration have dramatic effects on the size of the channels formed, providing an easy way for rapidly altering membrane permeability by changing the activity of local synthetic and catabolic enzymes. A possible role for these channels in apoptosis is discussed.     

Electrophoretic characterization of hepatic alkaline phosphatase released by phosphatidylinositol-specific phospholipase C. A comparison with liver membrane and serum-soluble forms.

Alkaline phosphatase was solubilized from plasma membrane of rat liver with butanol-ol, bile acids or sodium deoxycholate, and electrophoretically compared with a soluble form in serum which was derived from the liver. The three enzyme preparations from the plasma membrane migrated at the same position on polyacrylamide-gel electrophoresis in the presence of either Triton X-100 or sodium dodecyl sulphate. The mobility of them, however, was distinctly different from that of the serum-soluble form of the liver-derived alkaline phosphatase. On the other hand, phosphatidylinositol-specific phospholipase C isolated from Bacillus cereus was used to release alkaline phosphatase from plasma membrane. The released alkaline phosphatase was demonstrated to have the same mobility as the serum-soluble form on polyacrylamide-gel electrophoresis in the presence or absence of detergents. The phospholipase C also converted the butan-1-ol-extracted membrane form into the serum-soluble form. The results suggest that release of alkaline phosphatase from the liver into serum is not simply caused by a detergent effect of bile salts, but involves an enzymic hydrolysis of phosphatidylinositol, with which alkaline phosphatase may strongly interact in the membrane.     

Microbial degradation of [C14C]polystyrene and 1,3-diphenylbutane.

Microbial degradation of [beta-14C]polystyrene and 1,3-diphenylbutane, a compound structurally representing the smallest repeating unit of styrene (dimer), was investigated in soil and liquid enrichment cultures. Degradation rates in soil, as determined by 14CO2 evolution from applied [14C]polystyrene, varied from 1.5 to 3.0% for a 4-month period. Although relatively low, these percentages were 15 to 30 times greater than values previously reported. Enrichment cultures, containing 1,3-diphenylbutane as the only carbon souce, were used to determine the mechanisms of microbial oxidation of the polymer chain ends. Metabolism of 1,3-diphenylbutane appeared to involve the attack by a monooxygenease to form 2-phenyl-4-hydroxyphenylbutane followed by a further oxidation and subsequent fission of the benzene ring to yield 4-phenylvaleric acid and an unidentified 5-carbon fragment via the classic meta-fission pathway. Phenylacetic acid was probably formed from 4-phenylvaleric acid by subsequent beta-oxidation of the side chain, methyl-oxidation and decarboxylation. An initial examination of the population of microorganisms in the diphenylbutane enrichment cultures indicated that these oxidative reactions are carried out by common soil microorganism of the genera Bacillus, Pseudomonas, Micrococcus, and Nocardia.     

The phospholipids of Pneumococcus I-192R, A.T.C.C. 12213: Some structural rearrangements occurring under mild conditions

1. The phospholipids from the non-capsulated strain of Pneumococcus I-192R, A.T.C.C. 12213, were separated into three fractions by chromatography on columns of silicic acid and DEAE-cellulose (acetate form). 2. The water-soluble phosphate esters produced by deacylation of each fraction were separated by chromatography on columns of DEAE-cellulose (HCO(3) (-) form). 3. Three deacylated products, diglycerol phosphate, glycerylphosphorylglycerol phosphate and bis(glycerylphosphoryl)glycerol, were identified by analysis, by chemical degradations and by comparison with synthetic materials. 4. From a study of freshly isolated lipids prepared and worked up under conditions where exposure to acid was minimal, it was concluded that the Pneumococcus contains phosphatidylglycerol and bisphosphatidylglycerol, in the molar proportion 1:2.5-3.0, and that the deacylation product glycerylphosphorylglycerol phosphate was probably an artifact of the isolation procedure. 5. Acid-catalysed isomerization (phosphodiester migration) of diglycerol phosphate and bis(glycerylphosphoryl)glycerol and transesterification (glycerol phosphate transfer) of diglycerol phosphate were observed. The structures of the products were established by degradation. 6. A novel mechanism for the biosynthesis of bisphosphatidylglycerol is presented.     

The cell wall of Bacillus licheniformis N.C.T.C. 6346. Linkage between the teichuronic acid and mucopeptide components

1. After extraction of teichoic acid from cell walls of Bacillus licheniformis with dilute alkali, the insoluble residue contains the teichuronic acid and mucopeptide components and a small amount of residual phosphorus. 2. A complex of teichuronic acid and a part of the mucopeptide was isolated from the soluble fraction obtained by lysozyme treatment of alkali extracted walls. 3. Small-molecular-weight mucopeptide fragments, not containing teichuronic acid, are obtained from the soluble fraction in yields similar to those obtained after treatment of whole walls or acid-extracted walls with lysozyme. 4. The covalent linkages between teichuronic acid and mucopeptide are broken by treatment with dilute acid. The release of teichuronic acid chains is accompanied by the hydrolysis of N-acetylgalactosaminide linkages and the exposed N-acetylgalactosamine residues form chromogen under very mild conditions, indicating that they are substituted on C-3. 5. The initial rate of formation of reactive N-acetylgalactosamine residues during mild acid hydrolysis is parallel to the rate of extraction under the same conditions of teichuronic acid from alkali-treated insoluble walls, and to the rate of acid hydrolysis of glucose 1-phosphate. 6. The results suggest that the teichuronic acid chains are attached through reducing terminals of N-acetylgalactosamine residues to phosphate groups in the mucopeptide. 7. Muramic acid phosphate was isolated from the insoluble mucopeptide remaining after extraction of walls with dilute alkali followed by dilute acid.     

Host range of Cercospora apii and C. beticola and description of C. apiicola, a novel species from celery

The genus Cercospora is one of the largest and most heterogeneous genera of hyphomycetes. Cercospora species are distributed worldwide and cause Cercospora leaf spot on most of the major plant families. Numerous species described from diverse hosts and locations are morphologically indistinguishable from C. apii and subsequently are referred to as C. apii sensu lato. The importance and ecological role that different hosts play in taxon delimitation and recognition within this complex remains unclear. It has been shown that Cercospora leaf spot on celery and sugar beet are caused respectively by C. apii and C. beticola, both of which are part of the C. apii complex. During this study we characterized a new Cercospora species, C. apiicola, which was isolated from celery in Venezuela, Korea and Greece. The phylogenetic relationship between C. apiicola and other closely related Cercospora species was studied with five different gene areas. These analyses revealed that the C. apiicola isolates cluster together in a well defined clade. Both C. apii and C. beticola sensu stricto form well defined clades and are shown to have wider host ranges and to represent distinct species.