The Drosophila lethal(2)giant larvae tumor suppressor protein forms homo-oligomers and is associated with nonmuscle myosin II heavy chain

Inactivation of the Drosophila lethal(2)giant larvae (l(2)gl) gene causes malignant tumors in the brain and the imaginal discs and produces developmental abnormalities in other tissues, including the germline, the ring gland and the salivary glands. Our investigations into the l(2)gl function have revealed that the gene product, or p127 protein, acts as a cytoskeletal protein distributed in both the cytoplasm and on the inner face of lateral cell membranes in a number of tissues throughout development. To determine whether p127 can form oligomers or can stably interact with other proteins we have analyzed the structure of the cytosolic form of p127. Using gel filtration and immunoaffinity chromatography we found that p127 is consistently recovered as high molecular weight complexes that contain predominantly p127 and at least ten additional proteins. Blot overlay assays indicated that p127 can form homo-oligomers and the use of a series of chimaeric proteins made of segments of p127 fused to protein A, which alone behaves as a monomer, showed that p127 contains at least three distinct domains contributing to its homo-oligomerization. Among the proteins separated from the immuno-purified p127 complexes or isolated by virtue of their affinity to p127, we identified one of the proteins by microsequencing as nonmuscle myosin II heavy chain. Further blot overlay assay showed that p127 can directly interact with nonmuscle myosin II. These findings confirm that p127 is a component of a cytoskeletal network including myosin and suggest that the neoplastic transformation resulting from l(2)gl gene inactivation may be caused by the partial disruption of this network.

A physical and genetic map of the Stigmatella aurantiaca DW4/3.1 chromosome

A physical map of the myxobacterium Stigmatella aurantiaca DW4/3.1 chromosome was constructed by pulsed-field gel (PFG) long-range mapping. One-and two-dimensional pulsed-field gel analyses were used together with reciprocal double-restriction, cross-hybridization and hybridization fingerprint analysis. These PFG results were confirmed by Smith-Birnstiel analysis, by Southern hybridization using linking clones and clones of a lambda genomic library for the determination of adjacent restriction fragments and by transposon insertion mapping using defined genomic sequences for hybridization. It was thus possible to construct a circular restriction map of the single 9.35 Mbp chromosome of S. aurantiaca based on the endonucleases Asel and Spel. Genetic loci as well as the replication origin were located on the physical map by Southern hybridization using heterologous (derived from Myxococcus xanthus, Escherichia coli and Streptomyces lividans) and homologous probes that are mainly involved in development and cell motility.

Size and stability of the genomes of the myxobacteria Stigmatella aurantiaca and Stigmatella erecta

Genomic DNA of Stigmatella aurantiaca DW 4/3.1 was restricted with the rare-cutting endonucleases AseI and SpeI. The restriction pattern derived is composed of 33 AseI and 25 SpeI fragments, whose total size amounts to approximately 9,350 kbp. Genomic fingerprint analysis of chromosomal DNA from several S. aurantiaca isolates further revealed five completely different SpeI and AseI fingerprints and one distinct fingerprint for Stigmatella erecta. In addition, minor variations between the genome sizes of these isolates were observed.

Immunoblot for densitometric estimation of antibodies (IDEA): a useful method for quantification of intrathecally produced antibodies against individual antigens in infectious diseases of the central nervous system

Intrathecally produced antibodies specific for the infectious agent can be shown by immunoblot. A quantification is practicable by titration. Densitometric evaluation of the immunoblot by a new technique, IDEA (immunoblot for densitometric estimation of antibodies), does not only render titration unnecessary, but also has the advantage of presenting the differentiated local immune response against individual antigens of the infectious agent. Preliminary studies for the densitometric evaluation were performed with a measles virus immunoblot which had been developed with a cerebrospinal fluid (CSF) sample of a patient suffering from multiple sclerosis containing high antibody titers. A peroxidase-labeled anti-immunoglobulin antibody had been added. The intensity of the color reaction on the membrane dependent on the antibody concentration follows a saturation kinetics comparable to the Michaelis-Menten kinetics in enzymology. Thus, indices for the intrathecal antibody synthesis of each individual viral antigen can be calculated by taking the permeability of the blood-CSF barrier into consideration. This method is illustrated in a patient with zoster meningoencephalitis.

Second generation biosensors

Enzyme-membrane electrodes using glucose oxidase in combination with peroxide detection dominate in the field of laboratory analyzers for diluted samples. Using the same indication principle, extremely fast responding glucose sensors have been fabricated by covering thin metal electrodes with a porous enzyme layer. In the second generation auxiliary enzymes and/or co-reactants are coimmobilized with the analyte converting enzyme in order to improve the analytical quality and to simplify the performance. Following this line oxidizable interferences are suppressed by using a glucose oxidase/peroxidase complex which communicates with the electrode at a low working potential. Furthermore, fluctuations of pH or buffer capacity are ineffective when using a glucose oxidase/peroxidase layer covered fluoride FET in the potentiometric glucose determination. Enzymatic recycling of the analyte and/or accumulation of intermediates increase the sensitivity by several orders of magnitude. Inclusion of NAD bound to PEG in the glucose dehydrogenase layer allows a reagentless glucose measurement.

Fine specificities of antibodies in sera and cerebrospinal fluid in herpes virus infections of the central nervous system as detected by the antigen variable immunoblot technique

Applying the immunoblot technique a sensitive and specific method was developed for the detection of intrathecally synthesized antibodies against individual specific proteins that are antigens of various infectious agents causing encephalitis. Paired serum and cerebrospinal fluid (CSF) samples from five patients with herpes virus infections of the central nervous system (CNS) (three herpes simplex virus encephalitis, one varicella zoster virus encephalitis, one zoster ganglionitis) were investigated for the presence of locally produced IgG against the electrophoretically separated antigens of herpes simplex virus (HSV), varicella zoster virus (VZV) and human cytomegalovirus (HCMV), as well as for IgM antibodies in one case of HSV encephalitis. In two cases (HSV encephalitis and VZV encephalitis) four and one antibody, respectively, were found that were synthesized intrathecally only. In the other cases the patterns of sera and CSF antibodies were similar, the CSF antibodies showing an all-over stronger reaction, at identical IgG concentrations. In contrast to the conception of a 'limited heterogeneity' of intrathecal antibody synthesis in encephalitis, we thus found an 'expanded heterogeneity' of the intrathecally synthesized antibodies in comparison to the corresponding serum antibodies.

[Serologic studies in the diagnosis of pneumonia]

The importance of serological determination procedures for the diagnosis of pathogens was investigated in 207 episodes of pneumonia. The pathogenic organisms were detected in 138 cases; in 40 cases serological analysis helped to establish the diagnosis, while in 11 cases of pneumonia, the diagnosis was possible only with serology. The organisms most commonly found by serological investigations were Cytomegalovirus (n = 10), Aspergillus fumigatus (n = 7), and the influenza B virus (n = 7). Multiple infections, usually triggered by bacterial pathogens, were found in 48% of the cases of pneumonia with serological evidence of pathogens. In 71 episodes of pneumonia, the patients were immunosuppressed; in 11 cases, the causative organism was detected serologically.

Detection of HIV RNA by in situ hybridization in peripheral blood mononuclear cells of seronegative children born to HIV-infected mothers

Of 44 children born to human immunodeficiency virus (type 1) (HIV)-infected mothers, 11 have become seronegative. After the loss of maternal antibodies all children were analysed for several immunological functions and virological parameters in order to determine their HIV status. All children to date are clinically healthy and have normal immune functions. HIV-1 was detected by p24 antigen in one child, by in situ hybridization in nine children while viral cultures were all negative. These data suggest that the rate of vertical transmission of HIV-1 may be underestimated if seronegative children are considered to be not infected. They also suggest that molecular biological techniques are more sensitive than HIV antigen assay or viral cultures.

Clonal and variable properties of Neisseria meningitidis isolated from cases and carriers during and after an epidemic in The Gambia, West Africa

A representative collection of meningococci was isolated from cases and healthy carriers in The Gambia between 1982 and 1988, during and after an epidemic of meningococcal meningitis. These bacteria were subjected to a clonal analysis. All serogroup A bacteria from both cases and carriers were of one clone (A IV-1). Several unrelated clones were observed among serogroup 29E and serogroup Y carrier strains. The serogroup A strains were uniform for serotype and subtype antigens (serotype 4, subtype P1.7) and antibiotic sensitivity pattern. Occasional strains varied in their lipopolysaccharide (LPS), DNA fingerprint pattern, and/or the quantitative expression of the class 1 protein. A high degree of strain-specific variation was found for the expression of class 5 proteins, pili, and sulfonamide sensitivity. The frequency of strains expressing reduced amounts of the class 1 protein, altered LPS, and/or increased amounts of capsular polysaccharide rose among case strains obtained after the epidemic had ceased. These strains seem to be generally resistant to antibody-mediated bactericidal activity.

Trends in adolescent alcohol consumption in Halifax, Nova Scotia--1970-1986

The drinking behaviours of 1,128 students from grades 7 to 12 in Halifax, Nova Scotia were surveyed and the results were compared to surveys done on similar samples of adolescents in 1970, 1976 and 1983. The survey instruments were self-administered, anonymous questionnaires administered in class groups. In the 1986 survey, while no differences (p greater than .05) in the frequency of drinking episodes exists between males and females, the former group were found to be drinking more heavily. Since 1983, the percentage of drinkers has declined significantly (p less than .05) among both sexes. The percentage of frequent drinkers (once a week or more) and heavy drinking (6+ drinks per sitting, more than once per week) has not changed significantly (p greater than .05) in either sex.