Isolation and description of a non-motile,fusiform, stalked bacterium,a representatieve of a new genus

A single strain representing the fusiform group of caulobacters first described by Henrici and Johnson has been isolated from a freshwater pond. Like the genusCaulobacter this is a chemo-organotrophic bacterium that has one polar prostheca, a stalk in the sense that its apical holdfast permits the cell to attach to solid substrates. Fine structure studies reveal, however, that the prostheca of this organism contains typical cellular constituents, not the membranous material found in the stalks ofCaulobacter andAsticcacaulis. The organism also differs from the other caulobacters in having no motile stage and no dimorphic life cycle (both daughter cells are stalked at the time of division). Because only one strain has been isolated no nomenclatural proposals are made, but sufficient evidence is presented to indicate that this is a representative of a new genus of the Schizomycetes.     

Purification, cloning, and characterization of a profibrinolytic plasminogen-binding protein, TIP49a

The plasminogen receptors responsible for enhancing cell surface-dependent plasminogen activation expose COOH-terminal lysines on the cell surface and are sensitive to proteolysis by carboxypeptidase B (CpB). We treated U937 cells with CpB, then subjected membrane fractions to two-dimensional gel electrophoresis followed by ligand blotting with (125)I-plasminogen. A 54-kDa protein lost the ability to bind (125)I-plasminogen after treatment of intact cells and was purified by two-dimensional gel electrophoresis and then sequenced by mass spectrometry. Two separate amino acid sequences were obtained and were identical to sequences contained within human and rat TIP49a. The cDNA for the 54-kDa protein matched the human TIP49a sequence, and encoded a COOH-terminal lysine, consistent with susceptibility to CpB. Antibodies against rat TIP49a recognized the plasminogen-binding protein on two-dimensional Western blots of U937 cell membranes. Human (125)I-Glu-plasminogen bound specifically to TIP49a protein, and binding was inhibited by epsilon-aminocaproic acid. A single class of binding sites was detected, and a K(d) of 0.57 +/- 0.14 microm was determined. TIP49a enhanced plasminogen activation 8-fold compared with the BSA control, and this was equivalent to the enhancement mediated by plasmin-treated fibrinogen. These results suggest that TIP49a is a previously unrecognized plasminogen-binding protein on the U937 cell surface.     

Identification of a wheat allergen,Tri a Bd 36K,as a peroxidase

A 36-kDa allergen, Tri a Bd 36K, was purified from wheat albumin and characterized. The protein was similar to barley peroxidase BP-1 both in its amino acid sequence and peroxidase activity. The enzyme seemed to contain L-fucose and D-mannose and the glycan moiety reacted with IgE antibodies in a patient's serum.     

Wah Soon Chow,a teacher,a friend and a colleague

Photosynthesis Research - To finish this special issue, some friends, colleagues and students of Prof. Chow (Emeritus Professor, the Research School of Biology, the Australian National University)...     

An allotypic specificity presumably of the a series in rabbit immunoglobulins, different from a1, a2, and a3

From the serum of a wild rabbit lacking all the known allotypic specificities of the a series, IgG showing an allotypic specificity named. A100 has been isolated and antisera against it prepared in domestic rabbits. The determinants responsible for the A100 allotypic specificity are present both on IgG and IgM. They are located on the heavy chain and the Fab fragment of IgG.Evidence for the genetic determinism of A100 suggests that it is the product of a new allele at the $\text{a}$ locus.     

Ending a decade of deception: a valiant failure, a not-so-valiant failure, and a success story

Prior studies involving two methods, Brooks Parsimony Analysis (BPA) and TreeMap, have found BPA to be the more reliable method. Recent criticisms leveled at these studies argue that the tests were unfairly created and biased in favor of BPA. The authors of a recent critique offered new exemplars to demonstrate flaws in BPA, plus a simple fix to correct the flaws found in TreeMap. A re‐evaluation of their exemplars clearly shows that the authors' calculations are incorrect, their understanding of the methods is lacking, and that their simple fix does not work. Additional analyses using TreeMap 2.02 are run to show that TreeMap 2.02, like TreeMap 1.0, cannot adequately deal with widespread parasites, contrary to the claims of its supporters. Furthermore, the exemplars corroborate previous findings that BPA, when calculated correctly, is more reliable than TreeMap1.0 and TreeMap 2.02 and therefore the method of choice in coevolutionary and biogeographic studies.     

Study of a novel glycoconjugate, thiopeptidoglycan, and a novel polysaccharide lyase, thiopeptidoglycan lyase

A typical filamentous bacterium, Sphaerotilus natans, secretes a thiolic glycoconjugate which is assembled into a microtube, so called sheath. The glycoconjugate is known to consist of a pentasaccharide-dipeptide repeating unit, but its chemical structure has not been completely elucidated. In order to determine its chemical structure, the sheath was broken down by performic acid oxidation. The released sulfonated derivative was water soluble which was suitable for detailed NMR analysis. The data exhibited the presence of two stoichiometric and one substoichiometric (relative abundance was about 0.5) acetylations, suggesting that the glycoconjugate is composed of two equimolar pentasaccharide-dipeptide repeating units each having either two or three acetyl groups. However, the position of substoichiometric acetylation could not be defined. To determine the position, the sheath was derivatized with a thiol selective fluorescent reagent followed by digestion with a specific polysaccharide lyase prepared from a sheath-degrading bacterium, Paenibacillus koleovorans. As expected, two fluorescent digests were recovered by reverse-phase HPLC and were subjected to NMR analysis. The data revealed that both digests are pentasaccharide-dipeptides which have unsaturated glucuronic acid and galactosamine residues at their reducing and non-reducing ends, respectively. It was also confirmed that one digest has 3-O-acetylated glucose residue while the other has non-derivatized glucose residue. The substoichiometric acetylation was thus identified with the 3-O-acetylation, and structural determination of the thiolic glycoconjugate was completed. By virtue of the clarification of the two digests' structures, the cleavage site was specified as (1→4)-α-galactosaminic bond to glucuronic acid. Based on the present and earlier findings, we propose a novel glycoconjugate category named thiopeptidoglycan and a novel polysaccharide lyase named thiopeptidoglycan lyase.     

Chlorxanthomycin,a fluorescent,chlorinated, pentacyclic pyrene from a Bacillus sp

A gram-positive Bacillus sp. that fluoresces yellow under long-wavelength UV light on several common culture media was isolated from soil samples. On the basis of carbon source utilization studies, fatty acid methyl ester analysis, and 16S ribosomal DNA analysis, this bacterium was most similar to Bacillus megaterium. Chemical extraction yielded a yellow-orange fluorescent pigment, which was characterized by X-ray crystallography, mass spectrometry, and nuclear magnetic resonance spectroscopy. The fluorescent compound, chlorxanthomycin, is a pentacyclic, chlorinated molecule with the molecular formula C22H15O6Cl and a molecular weight of 409.7865. Chlorxanthomycin appears to be located in the cytoplasm, does not diffuse out of the cells into the culture medium, and has selective antibiotic activity.     

Production,in Pichia pastoris,of a recombinant monomeric mapacalcine,a protein with anti-ischemic properties

Mapacalcine is a small homodimeric protein of 19 kDa with 9 disulfide bridges extracted from the Cliona vastifica sponge (Red Sea). It selectively blocks a calcium current insensitive to most calcium blockers. Specific receptors for mapacalcine have been described in a variety of tissues such as brain, smooth muscle, liver, and kidney. Previous works achieved on hepatocytes and nervous cells demonstrated that this protein selectively blocks a calcium influx triggered by an ischemia/reperfusion (I/R) shock and efficiently protects cells from death after I/R. The aim of this work was to produce the recombinant mapacalcine in the yeast Pichia pastoris. Mass spectrometry, light scattering analysis and biological characterization demonstrated that the recombinant mapacalcine obtained was a monomeric form with 4 disulfide bridges which retains the biological activity of the natural protein.     

The hydration of a zwitterion, glycine, as a function of pH.

1. The hydration numbers of glycine (concentrations 1--3 M), as a function of concentration, were determined by surface tension measurements, using octan-1-ol as a 'reference' substance. 2. The hydration number of glycine at the isoelectric point decreased from 17.7 to 10.7 upon increasing the concentration from 1 to 3 M. 3. The changes in hydration of glycine as a function of the pH are due to the difference between hydrations of the ionized functional groups (NH+3, COO-) and the added ions (Me+ A-).