Covalent cross-linking of the bovine somatotropin dimer. Effects on growth-promoting, receptor-binding and immunological activities and preliminary characterization of the self-association.

Bovine somatotropin, at pH 8.5 in 0.02 M-Bicine [NN-bis-(2-hydroxyethyl)glycine]/0.09M-NaCl, showed by frontal analysis the characteristics of a rapid monomer-dimer equilibrium whose dissociation constant was estimated to be 6.6 X 10(-6)M. Reaction of the hormone with dimethyl suberimidate lead to covalent cross-linking of the dimeric species. Under the conditions chosen (0.4 mg of bifunctional imidate and 1 mg of protein/ml at room temperature for 1 h) the cross-linked dimers accounted for 26% of the total protein, and these were isolated by molecular sieving in 0.29M-NH3/0.12M-NaCl. Covalent stabilization greatly diminished the growth-promoting activity and the ability to interact with somatogenic sites in both rat liver in vivo and rabbit liver microsomal fractions. Evidence indicating a non-critical role for amino groups involved in the covalent cross-linking was provided by a nearly equivalent derivative obtained after reaction with 3,3'-dithiobispropionimidate, which had substantial hormonal activity upon cleavage of the disulphide links. Conversely, immunological reactivity as demonstrated by radioimmunoassay was not affected by cross-linking. Details of the least-squares procedure employed to evaluate the self-association equilibrium constant has been deposited as Supplement SUP 50115 (7 pages) with the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem.J. (1981) 193,5.     

Quantitative evaluation of the allometric transformation of of biological structures

Detection and quantification of allometry is a crucial problem in understanding morphological changes, both for systematic and morphogenetic purposes. A section of S.A.M. (Shape Analytical Morphometry) software system was used for this attempt. It consists of the following steps: a) boundary detection; b) starting point detection; c) size normalization; d) extraction of the fundamental shape by Kth order polynomials; e) finding of symmetry evaluator (S.A.E.) by means of a second degree equation. This last procedure gives an arc-chord complex that expresses a vector for allometry where intercept value was for application point, first degree coefficient was for direction and second degree coefficient was for modulus and versus. The main parameters, isometry fraction and allometry fraction may be understood referring them to morphogenetic models.     

Microplanktonic distributional patterns west of the Antarctic Peninsula,with special emphasis on the Tintinnids

Summary Microplankton was sampled with a centrifugal suction pump in the surface layer (approx. 9 m) of the Bellingshausen Sea and the Bransfield Strait in March 1987, and concentrated with a 26m-mesh net. Bulk microplanktonic settling volumes were assessed, silicoflagellates and large thecate dinoflagellates were counted, and tintinnids were counted and identified to species. Average (and maximum) values for the entire area surveyed were as follows, settling volume: 6.7 (43.3) ml/m³; silicoflagellates: 674 (7777) ind./l, 0.57 (6.54) mg C/m³; dinoflagellates: 109 (1321) ind./l, 1.40 (16.98) mg C/m³; tintinnids: 52 (589) ind./l, 1.15 (9.87) mg C/m³. The three geographic zones defined objectively on the basis of tintinnid specific assemblages also differed sharply in their surface salinity, overall microplanktonic abundance and bulk settling volume. The Bransfield Strait, with lowest settling volume values (2.1 ml/m³) and cell concentrations, was characterized by the dominance of Cymatocylis affinis/convallaria. In waters around the tip of the Antarctic Peninsula microplanktonic settling volumes averaged 4.6 ml/m³, cell concentrations were intermediate, and 79% of the tintinnids were represented by Codonellopsis balechi. The Bellingshausen Sea was characterized by the lowest salinities and the highest settling volumes (8.7 ml/m³) and cell counts; Laackmanniella spp. and Cymatocylis drygalskii, f. typica dominated this area. Almost all biological variables were significantly intercorrelated, and showed strong and mostly significant negative correlations with surface salinity, yet relationships between enhanced standing stock and ice meltwater were not obvious; rather, highest microplanktonic concentrations seemed to be due to ice-associated growth. Extremely high spatial correlations were found between the tintinnids and the dinoflagellates (r²: 0.941), suggesting the existence of close links between these two groups. Tintinnid species-specific assemblages show a coherent distributional pattern and well defined environment-related trends; most clearly differentiated preferences are exhibited by Laackmanniella prolongata (closely associated with ice-covered areas), Cymatocylis affinis/convallaria (oligotrophic open-ocean waters), and Codonellopsis balechi (coastal regions).     

Effect of waterfowl (Anas platyrhynchos) on indicator bacteria populations in a recreational lake Madison, Wisconsin.

A public swimming beach in Madison, wis., experienced intermittent high fecal coliform counts during the late summer and early fall of 1978. Public health officials closed the beach on a number of occasions. A public health survey identified a combination of waterfowl wastes and meteorological events as the explanation for the high bacteria counts. Fecal coliform bacteria were deposited by mallard ducks and multiplied in the beach sands. The bacteria were subsequently transported into the lake and resulted in high fecal coliform counts in the swimming area.     

Diversification of DNA sequences in the symbiotic genome of Rhizobium etli

Bacteria of the genus Rhizobium and related genera establish nitrogen-fixing symbioses with the roots of leguminous plants. The genetic elements that participate in the symbiotic process are usually compartmentalized in the genome, either as independent replicons (symbiotic plasmids) or as symbiotic regions or islands in the chromosome. The complete nucleotide sequence of the symbiotic plasmid of Rhizobium etli model strain CFN42, symbiont of the common bean plant, has been reported. To better understand the basis of DNA sequence diversification of this symbiotic compartment, we analyzed the distribution of single-nucleotide polymorphisms in homologous regions from different Rhizobium etli strains. The distribution of polymorphisms is highly asymmetric in each of the different strains, alternating regions containing very few changes with regions harboring an elevated number of substitutions. The regions showing high polymorphism do not correspond with discrete genetic elements and are not the same in the different strains, indicating that they are not hypervariable regions of functional genes. Most interesting, some highly polymorphic regions share exactly the same nucleotide substitutions in more than one strain. Furthermore, in different regions of the symbiotic compartment, different sets of strains share the same substitutions. The data indicate that the majority of nucleotide substitutions are spread in the population by recombination and that the contribution of new mutations to polymorphism is relatively low. We propose that the horizontal transfer of homologous DNA segments among closely related organisms is a major source of genomic diversification.     

Report of an archaic human skeleton discovered at altamura (Bari), in the “Lamalunga” district

The circumstances of the discovery and the first morphological observations concerning an, archaic human skeleton found in Altamura (Bari), in the “Lamalunga” district are reported. The observations were made by anthropologists from Bari University, at the site of the discovery, in a cave (Le Solange cave), a few days after they were first spotted by speleologists from the Speleological Research Center of Altamura (C.A.R.S.) and from the “Vespertilio” group of the Italian Alpine Club (C.A.I.) of Bari. The human remains were found in a corner of a small cavity in close association with columnar stalagmitic formations. All the bones are partly covered with, or embedded in, calcareous concretion while others are visible but lined with a calcareous shell of varying thickness. It is possible to recognize the skull (lying on its back); part of the face is apparent including the orbits and all the frontal region. On the ground, very close to the skull, there are many postcranial bones, but not all immediately recognizable because of the concretions. Immediately in front of and below the frontal are the tworadii; between these and a femoral shaft is the complete, but inverted, mandible. Bothfemora, thetibiae and thefibulae are present. Furthermore, the righthumerus, the distal epiphysis of an ulna and some costal elements are recognizable. The elements furthest from thecranium appear to be the innominate bones, partly covered with calcitic crust. Inside the pelvis are heavily, concreted pieces of bone among which are a costal element and a vertebral body. From the general robusticity of the bones and the rather high and narrow iliac fossa, the skeleton can be judged that of an adult male. Considering the presence on thecranium at the same time of both progressive and ancient features the Altamura specimen can be placed in the group of fossils of the European mid-Pleistocene characterized by the presence of archaic morphological traits and by a progressive increase in Neanderthal traits.     

Antimicrobial Activities of Methanol,Ethanol and Supercritical CO2 Extracts of Philippine Piper betle L. on Clinical Isolates of Gram Positive and Gram Negative Bacteria with Transferable Multiple Drug Resistance

Piper betle L. has traditionally been used in alternative medicine in different countries for various therapeutic purposes, including as an anti-infective agent. However, studies reported in the literature are mainly on its activities on drug susceptible bacterial strains. This study determined the antimicrobial activities of its ethanol, methanol, and supercritical CO₂ extracts on clinical isolates of multiple drug resistant bacteria which have been identified by the Infectious Disease Society of America as among the currently more challenging strains in clinical management. Assay methods included the standard disc diffusion method and the broth microdilution method for the determination of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentrations (MBC) of the extracts for the test microorganisms. This study revealed the bactericidal activities of all the P. betle leaf crude extracts on methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), extended spectrum β-lactamase-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, and metallo-β-lactamase-producing Pseudomonas aeruginosa and Acinetobacter baumannii, with minimum bactericidal concentrations that ranged from 19μg/ml to 1250 μg/ml. The extracts proved to be more potent against the Gram positive MRSA and VRE than for the Gram negative test bacteria. VRE isolates were more susceptible to all the extracts than the MRSA isolates. Generally, the ethanol extracts proved to be more potent than the methanol extracts and supercritical CO₂ extracts as shown by their lower MICs for both the Gram positive and Gram negative MDRs. MTT cytotoxicity assay showed that the highest concentration (100 μg/ml) of P. betle ethanol extract tested was not toxic to normal human dermal fibroblasts (HDFn). Data from the study firmly established P. betle as an alternative source of anti-infectives against multiple drug resistant bacteria.