Measles Immunoglobulins in Subacute Sclerosing Panencephalitis

Normal responses of measles specific immunoglobulins M and G (IgM and IgG) were defined in 10 children with measles. Abnormal responses of measles IgM and IgG were found in both sera and cerebrospinal fluids from three cases of subacute sclerosing panencephalitis. In two patients the serum titres of measles IgM and IgG were abnormally high. The measles IgM was present during prolonged illnesses in serum and cerebrospinal fluid, which suggested a correlation with the known persistence of measles virus antigen in the brain of the three patients. It was concluded that both measles IgM and IgG may be produced within the central nervous system in subacute sclerosing panencephalitis.     

Mitogen-induced preferential synthesis of proteins during the G0 to S phase transition in human lymphocytes

We have followed the induction of protein synthesis in mitogen-activated human peripheral blood mononuclear cells during the transition from quiescence, or G0, through the prereplicative phase and into first S phase. Doses of mitogens optimal for proliferative response preferentially enhance the synthesis of a subset of intracellular proteins during the approximately 24-h lag interval. The mitogenic lectin phytohemagglutinin (PHA) and OKT3, a mitogenic monoclonal antibody to the CD3 component of the T cell antigen receptor, preferentially enhance bands of the same molecular weight in one-dimensional SDS-PAGE. The proteins are low detergent soluble (0.1% Triton X-100) "cytoplasmic" cellular components and some have been identified as single spots on two-dimensional gels. Bands of 51 and 66 kDa are induced early in lag phase (4 h after stimulation) but are transiently synthesized, decreasing later in lag phase. The majority of the mitogen-induced proteins, 39, 51, 55, 60, 73, and 95 kDa are enhanced by mid lag phase (12 h after stimulation). With the exception of the 55-kDa band, five of these proteins are clearly enhanced in T cells purified after mitogen stimulation. The same five bands show sustained synthesis in actively cycling cells 42-48 h after stimulation and are major synthesized proteins, and corresponding bands are synthesized in a transformed T cell line, MOLT-4. Two of the proteins in this group that are most prominently synthesized during the lag interval have been previously identified as the heat shock proteins, HSP 90 (95-kDa band) and HSC 70 (73-kDa band). We speculate that this group of five proteins, including HSP 90 and HSC 70, may be coordinately expressed in actively replicating T cells and may have some common structural or functional role in sustaining the replicative state.     

Pesticide exposure: the hormonal function of the female reproductive system disrupted?

Some pesticides may interfere with the female hormonal function, which may lead to negative effects on the reproductive system through disruption of the hormonal balance necessary for proper functioning. Previous studies primarily focused on interference with the estrogen and/or androgen receptor, but the hormonal function may be disrupted in many more ways through pesticide exposure. The aim of this review is to give an overview of the various ways in which pesticides may disrupt the hormonal function of the female reproductive system and in particular the ovarian cycle. Disruption can occur in all stages of hormonal regulation: 1. hormone synthesis; 2. hormone release and storage; 3. hormone transport and clearance; 4. hormone receptor recognition and binding; 5. hormone postreceptor activation; 6. the thyroid function; and 7. the central nervous system. These mechanisms are described for effects of pesticide exposure in vitro and on experimental animals in vivo. For the latter, potential effects of endocrine disrupting pesticides on the female reproductive system, i.e. modulation of hormone concentrations, ovarian cycle irregularities, and impaired fertility, are also reviewed. In epidemiological studies, exposure to pesticides has been associated with menstrual cycle disturbances, reduced fertility, prolonged time-to-pregnancy, spontaneous abortion, stillbirths, and developmental defects, which may or may not be due to disruption of the female hormonal function. Because pesticides comprise a large number of distinct substances with dissimilar structures and diverse toxicity, it is most likely that several of the above-mentioned mechanisms are involved in the pathophysiological pathways explaining the role of pesticide exposure in ovarian cycle disturbances, ultimately leading to fertility problems and other reproductive effects. In future research, information on the ways in which pesticides may disrupt the hormonal function as described in this review, can be used to generate specific hypotheses for studies on the effects of pesticides on the ovarian cycle, both in toxicological and epidemiological settings.     

Novel Immune-type Receptor Genes and the Origins of Adaptive and Innate Immune Recognition

The prototypic forms of teleost novel immune-type receptors(NITRs) consist of a variable (V) region, a unique V-like C2(V/C2) domain, a transmembrane region and a cytoplasmic tailcontaining immunoreceptor tyrosine-based inhibition motifs (ITIMs).NITRs encode diversified V regions in large multigene familiesbut do not undergo somatic rearrangement. Studies in four differentbony fish model systems have identified a number of differentorganizational forms of NITRs. Specifically, NITR genes encodeN-terminal ectodomains of the V-type but otherwise vary in the:total number of extracellular immunoglobulin domains, numberand location of joining (J) region-like motifs, presence oftransmembrane regions, presence of charged residues within transmembraneregions, presence of cytoplasmic tails, and/or distributionof ITIM(s) within the cytoplasmic tails. V region-containingNITRs constitute a far more complex family than recognized originallyand currently include individual members that potentially functionthrough inhibitory as well as activating mechanisms. The genomicorganization of the NITR gene cluster as well as the structuraldiversity and overall architecture of the NITR proteins is reminiscentof genes encoded at the mammalian leukocyte receptor cluster(LRC); however, there presently is no functional evidence tosupport an orthologous relationship between NITR and LRC geneproducts. Comparisons of the predicted structures of the NITRshave identified several short regions of sequence identity anda novel cloning strategy has been devised that selects for secretoryand transmembrane proteins that encode these short motifs. Usingthis approach, related genes termed immune-type receptors (ITRs)have been identified in cartilaginous fish. Taken together,these studies indicate that leukocyte regulatory receptors,including those that mediate natural killer function, mighthave emerged early in vertebrate evolution and that the NITR/ITRgenes represent a new and potentially highly significant linkbetween innate and adaptive immune responses.     

Transformation of Saccharopolyspora erythraea by electroporation of germinating spores: construction of propionyl Co-A carboxylase mutants

The introduction of plasmid DNA into germinating spores of an industrially improved strain of Saccharopolyspora erythraea was accomplished by electroporation. Various parameters affecting the efficiency of electroporation were examined. The most critical factor was the extent of spore germination. Electrocompetence was limited to a 4-h period following the initial emergence of the germ tube. Electroporation efficiencies as high as 2 × 10⁵ CFU μg⁻¹ of plasmid DNA were obtained using electrocompetent germlings. The optimal field strength was 12–14 kV cm⁻¹ with a pulse duration of 15–20 ms. Electrocompetent germlings were stored at −80°C without a significant decrease in transformation efficiency. The utility of this protocol was demonstrated by isolating a propionyl-CoA carboxylase mutant through targeted gene disruption and replacement. Received 3 April 1998/ Accepted in revised form 28 September 1998     

Sequence variations in small-subunit ribosomal RNAs of Hartmannella vermiformis and their phylogenetic implications

Evidence of associations between free-living amoebas and human disease has been increasing in recent years. Knowledge about phylogenetic relationships that may be important for the understanding of pathogenicity in the genera involved is very limited at present. Consequently, we have begun to study these relationships and report here on the phylogeny of Hartmannella vermiformis, a free-living amoeba that can harbor the etiologic agent of Legionnaires' disease. Our analysis is based on studies of small-subunit ribosomal RNA genes (srDNA). Nucleotide sequences were determined for nuclear srDNA from three strains of H. vermiformis isolated from the United Kingdom, Germany, and the United States. These sequences then were compared with a sequence previously obtained for a North American isolate by J. H. Gunderson and M. L. Sogin. The four genes are 1,840 bp long, with an average GC content of 49.6%. Sequence differences among the strains range are 0.38%-0.76%. Variation occurs at 19 positions and includes 2 single-base indels plus 14 monotypic and 3 ditypic single-base substitutions. Variation is limited to eight helix/loop structures according to a current model for srRNA secondary structure. Parsimony, distance, and bootstrap analyses used to examine phylogenetic relationships between the srDNA sequences of H. vermiformis and other eukaryotes indicated that Hartmannella sequences were most closely related to those of Acanthamoeba and the alga Cryptomonas. All ditypic sites were consistent with a separation between European and North American strains of Hartmannella, but results of other tests of this relationship were statistically inconclusive.