New molecular and epidemiological issues in mesothelioma: Role of SV40

Mesotheliomas are malignant tumors usually associated with occupational asbestos exposure. Simian virus 40 (SV40) is a DNA tumor virus that preferentially causes mesotheliomas when injected intracardially and/or intrapleurally into hamsters. SV40 also transforms human cells in tissue culture, and these cells contain extensive DNA damage. In the United States, at least 60% of human mesotheliomas contain and express SV40. In these tumor cells, the SV40 tumor antigen binds and inhibits the cellular tumor suppressors p53 and Rb. These findings suggest that SV40 may contribute to the development of those human mesotheliomas that occur in people not exposed to asbestos. SV40 may also facilitate asbestos-mediated carcinogenicity. The epidemiological data available are insufficient to address the role that SV40 may have played in contributing to the increased incidence of mesothelioma in the second half of this century. J. Cell. Physiol. 180:167–172, 1999. © 1999 Wiley-Liss, Inc.     

Targeting of endothelin receptor-B to the neural crest

Endothelin receptor B (Ednrb) plays a critical role in the development of melanocytes and neurons and glia of the enteric nervous system. These distinct neural crest-derived cell types express Ednrb and share the property of intercalating into tissues, such as the intestine whose muscle precursor cells also express Ednrb. Such widespread Ednrb expression has been a significant obstacle in establishing precise roles for Ednrb in development. We describe here the production of an Ednrb allele floxed at exon 3 and its use in excising the receptor from mouse neural crest cells by use of Cre-recombinase driven by the Wnt1 promoter. Mice born with neural crest-specific excision of Ednrb possess aganglionic colon, lack trunk pigmentation, and die within 5 weeks due to megacolon. Ednrb receptor expression in these animals is absent only in the neural crest but present in surrounding smooth muscle cells. The absence of Ednrb from crest cells also results in a compensatory upregulation of Ednrb expression in other cells within the gut. We conclude that Ednrb loss only in neural crest cells is sufficient to produce the Hirschsprungs disease phenotype observed with genomic Ednrb mutations.     

The impact of Hurricane Ivan on the primary productivity and metabolism of marsh tidal creeks in the NorthCentral Gulf of Mexico

Past research has examined hurricane impacts on marine communities such as seagrass beds, coral reefs, and mangroves, but studies on how hurricanes affect marsh tidal creeks are lacking despite the important ecological roles that marsh tidal creeks have in coastal ecosystems. Here we report on the impact of Hurricane Ivan, which made landfall on September 16, 2004, on the primary productivity and metabolism of six marsh tidal creeks in the NorthCentral Gulf of Mexico. The hurricane did not seem to have any large, lasting impact on nutrient concentrations, primary productivity, metabolism, and chlorophyll a concentration in the water-column of the marsh tidal creeks. In contrast, the hurricane seemed to largely decrease gross primary productivity, net productivity, and chlorophyll a concentration in the sediment of the marsh tidal creeks. The results observed for Hurricane Ivan were coincident with those observed for four other major storms that made landfall close to the study area during 2005, Tropical Storm Arlene and Hurricanes Cindy, Dennis, and Katrina. However, the apparent negative impact of major storms on the sediment of the marsh tidal creeks did not seem to be long-lived and appeared to be dissipated within a few weeks or months after landfall. This suggests that marsh tidal creeks mostly covered with bare sediment are less disturbed by hurricanes than other types of marine communities populated with bottom-attached and/or more rigid organisms, such as seagrass meadows, coral reefs, and mangroves, where hurricane impacts can be larger and last longer.     

In Vitro Nuclear Assembly Using Fractionated Xenopus Egg Extracts

Nuclear membrane assembly is an essential step in the cell division cycle; this process can be replicated in the test tube by combining Xenopus sperm chromatin, cytosol, and light membrane fractions. Complete nuclei are formed, including nuclear membranes with pore complexes, and these reconstituted nuclei are capable of normal nuclear processes.Open in a separate windowClick here to view.^{(28M, flv)}     

Solution structure of the tumor necrosis factor receptor-1 death domain.

Tumor necrosis factor receptor-1 death domain (TNFR-1 DD) is the intracellular functional domain responsible for the receptor signaling activities. The solution structure of the R347K mutant of TNFR-1 DD was solved by NMR spectroscopy. A total of 20 structures were calculated by means of hybrid distance geometry-simulated annealing using a total of 1167 distance constraints and 117 torsion angle constraints. The atomic rms distribution about the mean coordinate positions for the 20 structures for residues composing the secondary structure region is 0.40 A for the backbone atoms and 1.09 A for all atoms. The structure consists of six antiparallel alpha-helices arranged in a similar fashion to the other members of the death domain superfamily. The secondary structure and three-dimensional structure of R347K TNFR1-DD are very similar to the secondary structure and deduced topology of the R347A TNFR1-DD mutant. Mutagenesis studies identified critical residues located in alpha2 and part of alpha3 and alpha4 that are crucial for self-interaction and interaction with TRADD. Structural superposition with previously solved proteins in the death domain superfamily reveals that the major differences between the structures reside in alpha2, alpha3, and alpha4. Interestingly, these regions correspond to the binding sites of TNFR1-DD, providing a structural basis for the specificity of death domain interactions and its subsequent signaling event.     

Monoclonal antibodies to Cache Valley virus for serological diagnosis

Cache Valley virus (CVV) is a mosquito-borne virus in the genus Orthobunyavirus, family Peribunyaviridae. It was first isolated from a Culiseta inorata mosquito in Cache Valley, Utah in 1956 and is known to circulate widely in the Americas. While only a handful of human cases have been reported since its discovery, it is the causative agent of fetal death and severe malformations in livestock. CVV has recently emerged as a potential viral pathogen causing severe disease in humans. Currently, the only serological assay available for diagnostic testing is plaque reduction neutralization test which takes several days to perform and requires biocontainment. To expand diagnostic capacity to detect CVV infections by immunoassays, 12 hybridoma clones secreting anti-CVV murine monoclonal antibodies (MAbs) were developed. All MAbs developed were found to be non-neutralizing and specific to the nucleoprotein of CVV. Cross-reactivity experiments with related orthobunyaviruses revealed several of the MAbs reacted with Tensaw, Fort Sherman, Tlacotalpan, Maguari, Playas, and Potosi viruses. Our data shows that MAbs CVV14, CVV15, CVV17, and CVV18 have high specific reactivity as a detector in an IgM antibody capture test with human sera.     

Langerhans cells and cDC1s play redundant roles in mRNA-LNP induced protective anti-influenza and anti-SARS-CoV-2 immune responses

Nucleoside modified mRNA combined with Acuitas Therapeutics’ lipid nanoparticles (LNPs) has been shown to support robust humoral immune responses in many preclinical animal vaccine studies and later in humans with the SARS-CoV-2 vaccination. We recently showed that this platform is highly inflammatory due to the LNPs’ ionizable lipid component. The inflammatory property is key to support the development of potent humoral immune responses. However, the mechanism by which this platform drives T follicular helper (Tfh) cells and humoral immune responses remains unknown. Here we show that lack of Langerhans cells or cDC1s neither significantly affected the induction of PR8 HA and SARS-CoV-2 RBD-specific Tfh cells and humoral immune responses, nor susceptibility towards the lethal challenge of influenza and SARS-CoV-2. However, the combined deletion of these two DC subsets led to a significant decrease in the induction of PR8 HA and SARS-CoV-2 RBD-specific Tfh cell and humoral immune responses. Despite these observed defects, these mice remained protected from lethal influenza and SARS-CoV-2 challenges. We further found that IL-6, unlike neutrophils, was required to generate normal Tfh cells and antibody responses, but not for protection from influenza challenge.In summary, here we bring evidence that the mRNA-LNP platform can support the induction of protective immune responses in the absence of certain innate immune cells and cytokines.     

Genetic diversity,population structure and phenotypic variation in European Salix viminalis L. (Salicaceae)

To investigate the potential of association genetics for willow breeding, Salix viminalis germplasm was assembled from UK and Swedish collections (comprising accessions from several European countries) and new samples collected from nature. A subset of the germplasm was planted at two sites (UK and Sweden), genotyped using 38 SSR markers and assessed for phenological and biomass traits. Population structure, genetic differentiation (F _ST ) and quantitative trait differentiation (Q _ST ) were investigated. The extent and patterns of trait adaptation were assessed by comparing F _ST ?and Q _ST parameters. Of the 505 genotyped diploid accessions, 27 % were not unique. Genetic diversity was high: 471 alleles was amplified; the mean number of alleles per locus was 13.46, mean observed heterozygosity was 0.55 and mean expected heterozygosity was 0.62. Bayesian clustering identified four subpopulations which generally corresponded to Western Russia, Western Europe, Eastern Europe and Sweden. All pairwise F _ST values were highly significant (p?F _ST ???=???0.12), and the smallest between the Swedish and Eastern European populations (F _ST ??=??0.04). The Swedish population also had the highest number of identical accessions, supporting the view that S. viminalis was introduced into this country and has been heavily influenced by humans. Q _ST values were high for growth cessation and leaf senescence, and to some extent stem diameter, but low for bud burst time and shoot number. Overall negative clines between longitudinal coordinates and leaf senescence, bud burst and stem diameter were also found.     

A modified and automated version of the 'Fluorimetric Detection of Alkaline DNA Unwinding' method to quantify formation and repair of DNA strand breaks

Background  

Formation and repair of DNA single-strand breaks are important parameters in the assessment of DNA damage and repair occurring in live cells. The 'Fluorimetric Detection of Alkaline DNA Unwinding (FADU)' method [Birnboim HC, Jevcak JJ. Cancer Res (1981) 41:1889–1892] is a sensitive procedure to quantify DNA strand breaks, yet it is very tedious to perform.