Enantiocontrolled preparation of indolizidines: synthesis of (-)-2-epilentiginosine and (+)-lentiginosine.

A highly stereoselective approach to (-)-2-epilentiginosine and (+)-lentiginosine has been developed based on a diastereofacially selective cycloaddition of dichloroketene with a chiral dienol ether. The two naturally occurring indolizidines are each obtained enantioselectively (> or = 99:1) in ca. 8.5% overall yield.

Regiochemistry in the Pauson-Khand reaction: has a trans effect been overlooked?

Alkyne-dicobalt hexacarbonyl complexes have been studied by DFT to examine whether electronic differences in the acetylenic substituents could play a role in determining the regiochemical outcome in the Pauson-Khand reaction. It appears that in some instances the regiochemistry is, in fact, governed exclusively by the electronic nature of the acetylenic substituents through the discriminant loss of a carbon monoxide ligand.

Targeted disruption of the Kcnq1 gene produces a mouse model of Jervell and Lange-Nielsen Syndrome.

KCNQ1 encodes KCNQ1, which belongs to a family of voltage-dependent K(+) ion channel proteins. KCNQ1 associates with a regulatory subunit, KCNE1, to produce the cardiac repolarizing current, I(Ks). Loss-of-function mutations in the human KCNQ1 gene have been linked to Jervell and Lange-Nielsen Syndrome (JLNS), a disorder characterized by profound bilateral deafness and a cardiac phenotype. To generate a mouse model for JLNS, we created a line of transgenic mice that have a targeted disruption in the Kcnq1 gene. Behavioral analysis revealed that the Kcnq1(-/-) mice are deaf and exhibit a shaker/waltzer phenotype. Histological analysis of the inner ear structures of Kcnq1(-/-) mice revealed gross morphological anomalies because of the drastic reduction in the volume of endolymph. ECGs recorded from Kcnq1(-/-) mice demonstrated abnormal T- and P-wave morphologies and prolongation of the QT and JT intervals when measured in vivo, but not in isolated hearts. These changes are indicative of cardiac repolarization defects that appear to be induced by extracardiac signals. Together, these data suggest that Kcnq1(-/-) mice are a potentially valuable animal model of JLNS.

Caloric restriction inhibits seizure susceptibility in epileptic EL mice by reducing blood glucose.

PURPOSE: Caloric restriction (CR) involves underfeeding and has long been recognized as a dietary therapy that improves health and increases longevity. In contrast to severe fasting or starvation, CR reduces total food intake without causing nutritional deficiencies. Although fasting has been recognized as an effective antiseizure therapy since the time of the ancient Greeks, the mechanism by which fasting inhibits seizures remains obscure. The influence of CR on seizure susceptibility was investigated at both juvenile (30 days) and adult (70 days) ages in the EL mouse, a genetic model of multifactorial idiopathic epilepsy. METHODS: The juvenile EL mice were separated into two groups and fed standard lab chow either ad libitum (control, n=18) or with a 15% CR diet (treated, n=17). The adult EL mice were separated into three groups; control (n=15), 15% CR (n=6), and 30% CR (n=3). Body weights, seizure susceptibility, and the levels of blood glucose and ketones (beta-hydroxybutyrate) were measured over a 10-week treatment period. Simple linear regression and multiple logistic regression were used to analyze the relations among seizures, glucose, and ketones. RESULTS: CR delayed the onset and reduced the incidence of seizures at both juvenile and adult ages and was devoid of adverse side effects. Furthermore, mild CR (15%) had a greater antiepileptogenic effect than the well-established high-fat ketogenic diet in the juvenile mice. The CR-induced changes in blood glucose levels were predictive of both blood ketone levels and seizure susceptibility. CONCLUSIONS: We propose that CR may reduce seizure susceptibility in EL mice by reducing brain glycolytic energy. Our preclinical findings suggest that CR may be an effective antiseizure dietary therapy for human seizure disorders.

Highly enantioselective approach to indolizidines: preparation of (+)-(1S,8aS)-1-hydroxyindolizidine and (-)-slaframine.

A highly stereoselective approach to (-)-slaframine and its probable biosynthetic precursor (+)-(1S,8aS)-1-hydroxyindolizidine has been developed based on a diastereofacially selective cycloaddition of dichloroketene with a chiral dienol ether.

New pyridone approach: total synthesis of mappicine ketone (nothapodytine B).

A novel synthesis of mappicine ketone, which possesses strong selective activity against the herpes viruses HSV-1 and HSV-2, including those Acyclovir-resistant, and human cytomegalovirus (HCMV) has been efficiently accomplished. The synthesis highlights a new pyridone approach that effectively combines a double, intramolecular Michael addition in a conjugated ester-conjugated amide with oxidation-decarboxylation of the resulting piperidone.

Efficient, highly enantioselective synthesis of selina-1,3, 7(11)-trien-8-one, a major component of the essential oil of Eugenia uniflora.

The first synthesis of selina-1,3,7(11)-trien-8-one (1), a major constituent of the essential oil from the leaves of Eugenia uniflora, has been accomplished, with excellent stereo- and regiocontrol, in eight steps and in 12% overall yield from the known octalone derivative 2a.

Characterization of wheatgrass-derived barley yellow dwarf virus resistance in a wheat alien chromosome substitution line.

ABSTRACT Wheatgrass (Thinopyrum intermedium) possesses a high level of resistance to barley yellow dwarf virus (BYDV) subgroup I and subgroup II strains. A wheat line (P29), in which the 7D chromosome has been substituted with a group 7 chromosome from T. intermedium, was examined for the level of resistance to two subgroup I and two subgroup II BYDV strains. In P29 plants inoculated with the subgroup I PAV strains, the titer of virus in leaf and stem tissue was typically reduced 42 to 52% when compared with the BYDV-susceptible cv. Abe. P29 and 'Abe' had the same content of PAV in roots. These results and the absence of detectable virus in inoculated T. intermedium plants indicate that the complete resistance to subgroup I possessed by the wheatgrass has not been introgressed into P29. In contrast, P29 was completely resistant throughout the plant to the subgroup II strains, NY-RPV and NY-RMV, demonstrating that the complete resistance to subgroup II in T. intermedium was incorporated into P29. Further analysis of this resistance to NY-RPV showed that NY-RPV can replicate in mesophyll protoplasts of P29 and 'Abe', suggesting that this resistance is not operating at the single-cell level. Molecular marker analysis confirmed that the T. intermedium chromosome present in P29 is a different group 7 wheatgrass chromosome than that present in L1, a wheat line with BYDV resistance properties similar to those of P29.

The carboxy-terminal two-thirds of the cowpea chlorotic mottle bromovirus capsid protein is incapable of virion formation yet supports systemic movement.

Previous investigations into recombination in cowpea chlorotic mottle bromovirus (CCMV) resulted in the recovery of an unusual recombinant virus, 3-57, which caused a symptomless infection of cowpeas but formed no detectable virions. Sequence analysis of cDNA clones derived from 3-57 determined that mutations near the 5' terminus of the capsid protein gene introduced an early translational termination codon. Further mutations introduced a new in-frame start codon that allowed translation of the 3' two-thirds of the capsid protein gene. Based on the mutations observed in 3-57, wild-type CCMV clones were modified to determine if the carboxyl two-thirds of the capsid protein functions independently of the complete protein in long-distance movement. Analysis of these mutants determined that while virion formation is not required for systemic infection, the carboxy-terminal two-thirds of the capsid protein is both required and sufficient for systemic movement of viral RNA. This indicates that the CCMV capsid protein is multifunctional, with a distinct long-distance movement function in addition to its role in virion formation.

Deletions in the 3' untranslated region of cowpea chlorotic mottle virus transgene reduce recovery of recombinant viruses in transgenic plants.

The 3' untranslated region (UTR) adjacent to the capsid gene is frequently included with the transgene in the construction of capsid protein mediated virus resistant transgenic plants. Since ribonucleotide sequences within the 3' UTR are involved in the initiation of viral replication, the presence of this sequence may encourage the participation of the transgene in RNA recombination. Experiments were designed to explore the involvement of the 3' UTR of cowpea chlorotic mottle virus (CCMV) in RNA recombination events between transgenes and challenging viruses. Nicotiana benthamiana was transformed with CCMV transgenes consisting of the 3' two-thirds of the capsid gene and fragments of the associated 3' UTR lacking the terminal 69, 83, or 214 nucleotides. Plants were inoculated with wild-type CCMV transcripts for RNAs 1 and 2 and a movement defective RNA 3 transcript lacking the 3' third of the capsid gene. While no recombinant virus was detected in plants expressing 3' deletion constructs, 3% of control transformants containing an identical segment of the capsid gene with the complete 3' UTR yielded viable recombinant virus. These results suggest that RNA recombination between transgenic RNA and viral RNA can be reduced significantly by omitting or disrupting the 3' UTR in the transgene.

Recombination between viral RNA and transgenic plant transcripts.

Transformed plants expressing the 3' two-thirds of the cowpea chlorotic mottle virus (CCMV) capsid gene were inoculated with a CCMV deletion mutant lacking the 3' one-third of the capsid gene. Although the deletion inoculum replicates in inoculated cells, systemic infections occur only if recombination restores a functional capsid gene. Four of 125 inoculated transgenic plants, representing three different transgenic lines, became systemically infected. Analysis of viral RNA confirmed that RNA recombination had united the transgenic messenger RNA and the challenging virus through aberrant homologous recombination.

NIGMS human/rodent somatic cell hybrid mapping panels 1 and 2.

The NIGMS Human Genetic Mutant Cell Repository is currently distributing two well-characterized human/rodent somatic cell hybrid mapping panels. Mapping Panel 1 consists of DNA isolated from 18 hybrid cell cultures retaining from 1 to 19 human chromosomes. Mapping Panel 2 contains DNA from hybrids retaining 1 or 2 human chromosomes. All but 2 of the hybrids retain a single intact human chromosome. Mapping Panel 2 is also available as cell cultures. These resources should prove valuable to the Human Genome Project initiative. This article describes the sources of the hybrid cell cultures and the procedures utilized to prepare and characterize the panels.

Health implications of petroleum distillate ingestion.

The authors discuss the clinical approach to the management of hydrocarbon ingestions, including the role, implementation, and type of gastric decontamination utilized; the extent of medical evaluation, observation or hospitalization required; and the appropriate therapy for hydrocarbon pneumonitis. An appendix covers myocardial sensitization following inhalation abuse of hydrocarbons.

Characterization of a new human diploid cell line--IMR-91.

A human diploid fibroblast cell line has been established from the lung tissue of a male fetus. This has been characterized and frozen away in large quantity. A smaller quantity of fibroblastlike cells from skin has also been established, partially characterized, and placed in frozen storage from the same fetus. This project is in support of the National Institute on Aging research in general cell biology. The present lines designated IMR-91 lung and IMR-91 skin complement the previous human diploid fibroblast culture (IMR-90) established from a female fetus. The lack of random inactivation of one of the two X chromosomes in the present male line reduces the genetic heterogeneity inherent in the female line.