Electron cytochemistry of mycobacteria: Evidence that strongly acidic sulfate groups are present on the surface of H37Rv (virulent) strain ofMycobacterium tuberculosis

Cytochemical characterization of mycobacterial surfaces was carried out on virulent (H37Rv) and avirulent (H37Ra) strains ofMycobacterium tuberculosis. The results were quantified and compared with those obtained with three colony types of the opportunistic pathogenMycobacterium avium. Mycobacterium aurum, a rapidly growing, nonpathogenic species, served as a model for the cytochemical methods. Concanavalin A (ConA) reacted with -d-mannose and -d-glucose residues, whereas negative charged residues were detected with either the ionized ferritin (CF) or the colloidal ferric hydroxide (CIH) method. Strongly acidic sulfate groups were detected by their selective blockage with alcian blue (AB) at pH 1 prior to the CIH labeling at pH 1.8. Weakly acidic groups were demonstrated by AB blockage at pH 2.5 prior to staining with CF stain. Except forM. aurum, all other strains showed a marked heterogeneity in regard to the abundance of their surface labeling. Accessible sulfate groups were present on the cell surface of the virulent H37Rv strain ofM. tuberculosis, but not on the avirulent strain H37Ra. Distribution of ConA receptors, on the other hand, was unrelated to the virulence or pathogenicity of the bacterial strain.     

The complete nucleotide sequence of the colicinogenic plasmid ColA. High extent of homology with ColE1

Summary The complete nucleotide sequence of the colicinogenic plasmid ColA has been determined. The plasmid DNA consists of 6720 bp (molecular weight 4.48×10⁶). Fifteen putative biological functions have been identified using the functional map previously determined. These include 11 genes and 3 DNA sites. Nine genes encode proteins of which 3 have been fully characterized. The replication region of ColA coding for RNAI and RNAII is highly homologous to that of ColE1 andClo DF13. The same holds true for the site-specific recombination region containing palindromic symmetry and involved in stable maintenance of the plasmids. A high percentage of homology has been detected for putative mobility proteins encoded by ColA and ColE1. The exclusion proteins are also highly homologous.     

Restriction map construction using a 'complete sentences compatibility' algorithm

We have developed a new algorithm ‘Complete sentencescompatibility’ (CSC) which uses single and double digestionfragments to rapidly determine restriction maps of circularDNA. From possible combinations of fragments of each simpledigestion, which we call ‘sentences of decomposition’,we construct a restriction map which combines the sentenceswhile taking into account compatibility rules. The algorithmcan also deal with experimental errors of fragment weight andcan suggest solutions that account for non-readable bands (fragmentsof zero length or multiple bands) on the gel. Because experimentsusing pairs of restrictive enzymes often result in multiplesolutions, a complementary algorithm tries to reduce the numberof proposed solutions by establishing consensus maps. The restrictionmap construction algorithm was tested on real cases, some containingmore than fifteen fragments. Execution times range from 1 –10 s on an IBM PC compatible microcomputer. Received on July 21, 1987; accepted on December 31, 1987     

Conformations and dynamics of surfactants in micelles and liquid crystals by nuclear magnetic relaxation

The order parameters as well as the rates of overall and internal motions of aggregated surfactants can be obtained from deuteron and carbon-13 nuclear relaxation experiments. The main contribution to the relaxation is generally the quadrupolar coupling (²H) or the short range dipolar interaction with protons (¹³C). In some cases it is convenient to derive the same information from the¹³C relaxation induced by long range dipolar interactions with a paramagnetic probe exchanging rapidly among the polar heads of surfactant molecules. This paper outlines the methods of interpretation of relaxation data by means of a rotational jump model of internal motions, taking into account most of the accessible conformers. The conformational and dynamical parameters are obtained from the magnetic field dependence of the longitudinal relaxation rates (micelles) or from the simultaneous fit of these rates and of the dipolar or quadrupolar splittings (liquid crystals). Some examples of application of these methods are given from recent works on single and double detailed surfactants.     

A 126 bp fragment of a plant histone gene promoter confers preferential expression in meristems of transgenic Arabidopsis

The tissue-specific pattern of expression directed by the H4A748 Arabidopsis histone promoter was investigated by analysis of beta-glucuronidase (GUS) activity in transgenic Arabidopsis containing H4A748-GUS gene fusions. As determined by fluorimetric and histochemical tests, the H4A748 promoter directs preferential expression in meristems of young seedlings and adult plants. The low activity found in nonproliferating tissues may relate to basal constitutive expression of the histone promoter and/or to endoreduplication occurring in some tissues. The endogenous histone mRNA levels parallel the GUS activity found in different tissues. Analysis of the regulatory properties of 5' deleted promoters showed that multiple positive elements exist between -900 and -219 and that the proximal region of the promoter to -219 is sufficient to establish the full tissue-specific pattern of expression. Further deletion to -93 nearly abolished the promoter activity thus suggesting that the 126 bp fragment located between -219 and -93 contains the elements responsible for the specific expression pattern. The presence of several remarkable sequences within this fragment is discussed.     

Localization of alpha 1-microglobulin (HC protein) in normal human tissues: an immunohistochemical study using monoclonal antibodies

Summary Alpha-1-microglobulin is a low molecular weight (approximately 30 000 d) glycoprotein present in biological fluids. It is heterogeneous in charge. A monoclonal antibody was used to investigate the tissue distribution of the protein in normal human tissues and cell lines by indirect immunofluorescence and immunoperoxidase techniques. The protein was demonstrable in cells of the monocyte-macrophage lineage, in thymus and T cell dependent areas of spleen, lymph node and tonsils. It was detected in several lymphoid or nonlymphoid cell lines but not in peripheral blood lymphocytes. The microglobulin was also detectable in the cytoplasm of hepatocytes. Finally, it was observed in glandular secretions (sudoral glands and mucosal glands of the digestive tract) where it may be associated with IgA. Possible explanations for the highly divergent results previously reported with polyclonal antisera to ₁ microglobulin are discussed.     

Phénolamides et induction florale de Cichorium intybus dans différentes conditions de culture en serre ou in vitro

Phenolamides and floral induction of Cichorium intybus in different conditions of culture in glass-room or in vitro. Three complexes between phenols and amines (phenolamides) have been found in Cichorium intybus L., a plant with an absolute requirement of vernalisation followed by long days for flowering. Upon hydrolysis, these complexes (A, B and C) liberate aromatic amines whose exact identification is in progress, but which are closely related to dopamine, tyramine and serotonin, respectively. In a first series of experiments, phenolamides were studied in the buds of plants grown in the greenhouse under varying conditions. Only buds from plants which flower in long days contained large amounts of these compounds. Much smaller amounts were found in buds at the end of vernalisation (at 2–4°C) before long-day treatment as well as in buds kept in the vegetative state after vernalisation by being grown in short days (8 h light) or in total darkness. In a second series of experiments, phenolamides were studied in bud-forming calli induced in vitro on explants of tuberised root. After sixteen days of culture in continuous light, large quantities of phenolamide were found in the buds and calli of the upper part of the explant, while the lower part which never produces buds contained much less. Buds formed under continuous light produce inflorescences in approximately one month. Various other culture conditions make it possible to maintain the explants in the vegetative state. This can be obtained by short-day conditions, or otherwise under continuous illumination by decreasing the sugar or increasing the NAA levels in the medium. After 13 days of culture, the phenolamide levels were much lower under all of these conditions, than under conditions favourable to floral induction. Compound C is absent or present in trace amounts in vegetative buds. The significance of the differences observed between floral and vegetative buds is supported by the sensitivity of the analytical techniques used. The accumulation of phenolamides in tissues of Cichorium intybus appears to be closely linked to floral induction. Under continuous light it begins very early in young buds and even in the calli that bear these buds.     

In vitro fertilization with normal development in the sheep

Ovine tubal (n = 87) and ovarian in vitro matured oocytes (n = 99) were fertilized in vitro with ejaculated spermatozoa capacitated for 8 h in modified defined medium buffered with Hepes. High levels of fertilization were obtained as assessed by development to two-to six-cell stage within 40 h (75. 8% for ovulated and 62. 6% for in vitro matured oocytes). Electron microscope analysis of oocytes 20–22 h after insemination indicated that in vitro fertilization approximated the in vivo events. Embryos (two- to six-cell) were transferred surgically to the oviducts of pseudopregnant rabbits. Three days later, 42 (from ovulated oocytes) and 15 (from in vitro matured oocytes) embryos were recovered; 26 (61. 9%) and 10 (66. 6%), respectively, had cleaved at least once. Embryos incubated in vivo (n = 20 from ovulated oocytes; n = 9 from in vitro matured oocytes) were transferred surgically to the uteri of seven and four recipient ewes resulting in four and two pregnancies, respectively, from which three and one, respectively, have been maintained ( > 3 months). The first lamb resulting from the in vitro fertilization of an ovulated oocyte was born. In addition, six embryos (two- to four-cell) from tubal oocytes and ten embryos (two- to six-cell) from in vitro matured oocytes were directly transferred to the oviducts of two and three ewes, respectively. Two pregnancies resulting from in vitro matured fertilized oocytes are in progress ( > 3 months).     

On a simple epidemic model with a heterogeneous infective population

This paper is concerned with a generalization of the simple epidemic model in which the infective population is partitioned intom classes, each of specific infectiousness. Attention is restricted, however, to the case where all the meeting rates between two individuals are equal to each other. Both deterministic and stochastic versions are examined. In either case the development in time of the epidemic process is investigated by exploiting a connection with the standard simple epidemic model. Finally, it is shown that the technique used also applies to a similar model for the spread of information.