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J Bonin

Publications and source records attributed to J Bonin.

13 recordsLinked to original sources
PubMed2006

Solvation dynamics of the electron produced by two-photon ionization of liquid polyols. 1. Ethylene glycol.

Solvated electrons have been produced in ethylene glycol by two-photon ionization of the solvent with 263 nm femtosecond laser pulses. The two-photon absorption coefficient of ethylene glycol at 263 nm is determined to be beta = (2.1 +/- 0.2) x 10(-11) m W(-1). The dynamics of electron solvation in ethylene glycol has been studied by pump-probe transient absorption spectroscopy. So, time-resolved absorption spectra ranging from 430 to 710 nm have been measured. A blue shift of the spectra is observed for the first tens of picoseconds. Using the Bayesian data analysis method, the observed solvation dynamics are reconstructed with different models: stepwise mechanisms, continuous relaxation models, or combinations of stepwise and continuous relaxation. Comparison between models is in favor of continuous relaxation, which is mainly governed by solvent molecular motions.

Journal Article↗
PubMed1999

Liver fluke (Opisthorchiidae) findings in red foxes (Vulpes vulpes) in the eastern part of the Federal State Brandenburg, Germany--a contribution to the epidemiology of opisthorchiidosis.

Parasitological examination of 677 livers from red foxes shot in connection with a rabies control programme were carried out in the eastern districts of the Federal State Brandenburg/Germany in 1996. Of the foxes, 32.5% were positive for opisthorchiid flukes. Metorchis bilis, the most frequently occurring fluke was found in 28.1% of foxes with numbers between 1 and 185. Opisthorchis felineus was found in 6.7% of fox livers. A maximum of 169 specimens was removed from one animal. Pseudamphistomum truncatum was present in only 2 foxes. The percentage of positive foxes in different districts varied between 15.8 and 43.3%. Significant differences in fluke prevalence were found between districts with a high share of surface water compared with a district with a low percentage of surface water. No sex-dependent differences in opisthorchiid prevalence were established.

Animals↗
PubMed1997

Hindlimb deformities (ectromelia, ectrodactyly) in free-living anurans from agricultural habitats.

High prevalences of hindlimb deformities were recorded in wild-caught green frogs (Rana clamitans), northern leopard frogs (Rana pipiens), American toads, (Bufo americanus), and bullfrogs (Rana catesbeiana) from agricultural sites exposed to pesticide runoff in the St. Lawrence River Valley of Québec, Canada, between July and September 1992 and 1993. Of 853 metamorphosing anurans examined in 14 farmland habitats, 106 (12%; range 0 to 69%) had severe degrees of ectromelia and ectrodactyly, compared to only two (0.7%; range 0 to 7.7%) of 271 in 12 control sites. However, the variation in the proportion of deformities among sites was too large to conclude that there was a significant difference between control and pesticide-exposed habitats. Clinical signs varied and were characterized by segmental hypoplasia or agenesis of affected limbs. Conspicuous abnormalities interfered with swimming and hopping, and likely constituted a survival handicap. Because of circumstances and the frequency of these malformations in nine distinct habitats, and in three different species from one of our study sites, we propose a teratogenic action of exogenous factors. Despite the fact that many biotic and abiotic agents are potentially harmful to limb development, agricultural contaminants were suspected as primary aggressors. Thus, clinical examination and frequency of deformities in anurans might be an economical screening tool to assess ecosystem health and the presence of environmental contaminants.

Agriculture↗
PubMed1985

Antigenic variation and resistance to neutralization in poliovirus type 1.

Mutations have been identified in variants of poliovirus, type 1 (Mahoney) on the basis of their resistance to neutralization by individual monoclonal antibodies. The phenotypes of these variants were defined in terms of antibody binding; the pattern of epitopes expressed or able to be exploited for neutralization were complex. Single amino acid changes can have distant (in terms of linear sequence) and generalized effects on the antigenic structure of poliovirus and similarly constituted virions.

Amino Acid Sequence↗
PubMed1985

Natural variants of the Sabin type 1 vaccine strain of poliovirus and correlation with a poliovirus neutralization site.

Independent substitution mutations have been detected in capsid polypeptide VP1 of the type 1 oral poliovirus vaccine isolated from normal infant vaccine recipients. These mutations map at amino acid residues 142 and 147 of VP1, a region only minimally hydrophilic. A synthetic peptide, corresponding to residues 141 to 147 of VP1 was synthesized, conjugated to a carrier polypeptide of bovine serum albumin. The conjugate was found to elicit a weak poliovirus neutralizing antibody response. It was also capable of priming the immune system for the production of IgG-type antibodies able to neutralize greater than 99.999% of infectious type 1 virus. It is suggested that region 141 to 147 of VP1 may be involved in neutralization of the virus and that the mutants may have accumulated by antibody selection.

Antigen-Antibody Complex↗
PubMed1984

Recombinants of Mahoney and Sabin strain poliovirus type 1: analysis of in vitro phenotypic markers and evidence that resistance to guanidine maps in the nonstructural proteins.

A neutralizing monoclonal antibody-resistant variant of the Sabin vaccine strain of poliovirus type 1 and a guanidine-resistant variant of the virulent parent Mahoney strain were derived. The two variants were used, in a coinfection, to generate recombinant virus containing both resistance markers. Recombinants appeared on the order of 1.0 PFU for every 10(4) total PFU. Two independently derived recombinant viruses were isolated. Each isolate contained the P1 (structural protein) gene region of the Sabin strain virus and the P3 (nonstructural replicase protein) gene region of the Mahoney strain virus. The recombinant virus phenotypes were compared with certain characteristic in vitro phenotypes of both parents. It was found that the slow growth in cell culture, temperature sensitivity, and virion surface charge characteristics of the Sabin virus mapped entirely to the structural protein gene region whereas the phenotype of the actinomycin D sensitivity of the Sabin virus mapped to the gene region specifying the nonstructural replication proteins. Sequence analysis of the recombinant RNA revealed that the crossover occurred 3' of nucleotide 3919. This result showed that the resistance of poliovirus mutants to growth in 2 mM guanidine hydrochloride maps in the 3'-terminal region of the viral genome specifying the nonstructural proteins.

Antigens, Viral↗
PubMed1983

Mouse neurotropic recombinants of influenza A viruses.

Recombinants with known gene constellations between fowl plague virus (FPV) and various prototype influenza virus strains have been examined for neurovirulence in suckling mice. Strongly neurotropic recombinants were obtained from crosses between FPV and the strains virus N, Hong Kong, and PR8, but not between FPV and equi 2 or swine viruses. All highly neurotropic recombinants had RNA segment 4 (HA) derived from FPV and RNA segment 2 (Ptra gene) from the other prototype strain. The derivation of two other RNA segments of the polymerase complex, namely RNA segments 3 (Pol 2) and 5 (NP) and also segment 8 (NS) can modulate these properties. For example, if in recombinants between FPV and virus N in addition to RNA segment 2 also RNA segments 3 and/or 8 are derived from virus N, neurovirulence is further enhanced, while replacement of RNA segment 5 of FPV by the corresponding segment of virus N decreases or abolishes neurovirulence. The derivation of the other genes does not seem to be relevant for neurovirulence in the crosses mentioned above. Of the prototype strains tested, the turkey England (t. Engl.) strain is the only one which was highly neurotropic for suckling mice. Recombinants between FPV and t. Engl. which have kept the HA gene of t. Engl. were still neurotropic, while those with the HA gene of FPV were completely avirulent. The results obtained demonstrated that 1. the creation of influenza virus recombinants neurotropic for mice is not a rare event; 2. one of the parents should multiply well in mouse lungs; 3. the presence of a cleavable hemagglutinin is necessary, but not sufficient. In the pair FPV/turkey England the hemagglutinin of turkey England seems to determine neurovirulence.

Animals↗
PubMed1983

Pathogenesis of neurovirulent influenza A virus infection in mice. Route of entry of virus into brain determines infection of different populations of cells.

Coinfection of a cell culture with a human and avian influenza A virus had yielded a recombinant virus with high neurovirulence for mice. This study reports on the comparative pathogenesis of central nervous system infection in mice between the parental human and the recombinant virus using the immunohistologic peroxidase-antiperoxidase method and virus assay of tissue suspensions. The human virus replicated poorly in mice and did not replicate in the brain even after intracerebral inoculation. In contrast, the recombinant virus replicated to high titer in the lung and brain with resulting viremia after inoculation of young mice by the intracerebral, intraperitoneal, or intranasal routes. Different populations of cells in the brain became infected after inoculation by each of the three routes: choroid plexus, and ependymal and subependymal cells after intracerebral inoculation; cells in perivenous areas, neurons in the olfactory bulbs and trigeminal ganglia and nuclear groups in the brainstem and midbrain after intranasal inoculation. Intraperitoneal inoculation resulted almost exclusively in the perivenous spread of the virus. The intranasal inoculation suggested that virus entry into the brain both by spread along nerve cell processes from the nasal mucosa to the brain and trigeminal ganglia and subsequent perivenous spread after viremia developed following virus replication in the lung. To dissect these two mechanisms we inoculated neonatal mice that had acquired high levels of serum antibody by nursing from actively immunized mothers. Intraperitoneal inoculation of these mice failed to cause infection, whereas intranasal inoculation resulted in the same pattern of cellular spread through the olfactory and trigeminal pathways as noted previously. This proved that this recombinant influenza virus could invade the central nervous system after infection via a natural route of infection. This highly neuroinvasive agent provides one example of the extent of virulence which can be acquired by recombination of apathogenic influenza viruses and raises a note of caution for adequate control of those agents generated in the laboratory.

Animals↗
PubMed1980

Mechanism of translocation: effect of cognate transfer ribonucleic acids on the binding of AUGUn to 70S ribosomes.

We try to mimic the unidirectional sliding-type movement of the PP-tRNA . mRNA complex with respect to the ribosome by looking at the effect of different combinations of cognate tRNAs on the stability of the 70S-AUGUn complex. The association constant for the binary complex 70S-AUGU3 was determined as 6.8 x 10(5) M-1. Addition of tRNAfMet resulted in a 67-fold increase in the association constant, which with both cognate tRNAs is revised to Kassoc = 2.2 x 10(8) M-1. Increasing the chain length of the oligonucleotide from AUGU3 to AUGU13 did not further raise the association constant. The data indicate that the stability of the 70S ribosome . mRNA interaction is governed by the presence of the cognate tRNAs and is topographically restricted to the decoding domains. Since a peptidyl group in the tRNA increases the affinity of AUGU3 for the ribosome by up to 15-fold, we conclude that the affinity of the peptidyl transfer center for the peptidyl moiety pulls the PP-tRNA . mRNA complex from the A (aminoacyl-tRNA) site to the P (peptidyl-tRNA) site. EF-G . GTP or EF-G . GMPPCP 5'-(beta, gamma-methylene)triphosphate] displace tRNAfMet from the quaternary complex 70S . AUGUn . tRNAfMet . tRNAPhe (n = 3 and 6) at Mg2+ less than 25 mM. From the amount of EF-G . GTP bound to a 70S ribosome, it follows that the elongation factor replaces the deacylated tRNA in a stoichiometric way. These data indicate that the EF-G . GTP-dependent release of the deacylated tRNA from the P site, followed by removal of EF-G . GDP from the 50S subunit, is sufficient to trigger the translocation of the mRNA . PP-tRNA complex.

Biological Transport↗
PubMedDate not supplied

[Distribution of opisthorchiid liver flukes in red foxes (Vulpes vulpes) in western Brandenburg].

226 (= 43.9%) out of 515 red foxes originating from the western districts of the Federal State Brandenburg were positive for opisthorchiid flukes. Metorchis bilis, Opisthorchis felineus and Pseudamphistomum truncatum occurred in prevalences of 36.9, 8.9 and 0.2% respectively. Although low fluke burden were predominant the maximum number of each fluke species isolated was 419, 46, and 78 respectively. No clear relations were found between the liver fluke prevalence and the proportion of surface waters of the different administrative districts. However, most positive foxes originated from municipalities closely situated to rivers, canals, and lakes.

Animals↗
PubMedDate not supplied

[Neurotropic influenza type A viruses].

Influenza A/turkey/England/63 is neurotropic for mice. Substitution of the hemagglutinin gene of this virus by the corresponding gene of A/FPV/ Rostok /34 virus results in the loss of the neurotropic properties of the original virus. Examination of recombinants produced by hybridization of parental strains nonpathogenic (or weakly pathogenic) for newborn mice revealed recombinants highly virulent for this host. A correlation between constellation of genes and neurovirulence for mice was established. After intranasal administration neurovirulent viruses were shown to be able to penetrate into the brain of the infected animal along the trigeminal nerve escaping the blood stream.

Animals↗