Absence of satellite III DNA in the centromere and the proximal long-arm region of human chromosome 14: analysis of a 14p- variant.

Cytogenetic methods and molecular probes derived from the centromere and short arm of chromosome 14 were used to investigate the structural properties of a chromosome 14 variant. Results of GTL, CBG, Ag-NOR, and non-banded Giemsa staining of the chromosomes suggested the complete absence of the short arm and possibly a large part of the centromere. Negative in situ hybridisation with an alpha satellite III probe confirmed the absence of the arm; the detection of normal amounts of alpha satellite DNA, however, indicated retention of the centromeric domain. The natural occurrence of a human acrocentric variant lacking a short arm was thus established. Within the detection limits of the methods used, the results demonstrate that satellite III DNA is not essential for normal centromeric activity and allow us to exclude the presence of this satellite DNA within the centromere and proximal long-arm region of human chromosome 14.     

Doubled haploids for estimating genetic variances in presence of linkage and gene association

Summary The effect of gene association (or dispersion) and linkage on the estimation of genetic variances in a diallel experiment involving doubled haploid lines is evaluated. It is shown that the estimates of the additive and the additive X additive genetic variances, as obtained by Choo et al. (1979), are biased if genes are linked or are not independently distributed in the parents. However, this bias only occurs in the presence of interaction between homozygous loci. Gene association (or dispersion) and linkage, if present, can be detected by comparing the parental vs the crosses mean, the parental vs the doubled haploid lines variance, and the among vs the within crosses variance.     

Development of L-689,065 - the prototype of a new class of potent 5-lipoxygenase inhibitors

The combination of a 5-phenylpyridine substituent and a novel, substituted thiopyrano[2,3,4-c,d]indole ring system yields a potent and selective 5-lipoxygenase inhibitor, L-689,065.     

Application of modified ising model to the helix-coil transition of DNA molecules

Equilibrium properties of heterogeneous DNA near the melting temperature T_m are investigated using the grand partition function. The present approach gives exact and analytical solutions. The algebraic expressions enhance a more thorough understanding of the correlation among many observed equilibrium phenomena. The following quantities have been examined: melting temperature T_m, transition width W, partial melting curves θ_AT and θ_GC, mean length of a helical segment h, and correlation length γ.     

Nematicidal efficacy of herbal powders on Meloidogyne incognita (Tylenchida: Meloidogynidae) on potted watermelon

Nine herbal powders were tested against root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood (Tylenchida: Meloidogynidae) under greenhouse conditions. The herbal powders were collected from Gezira State, Sudan. Herbal powders were used without extraction to simplify the application by farmers. Most of the herbal powders were effective in controlling M. incognita in the soil compared to the control. Some treatments (e.g., Acacia nilotica (L.), Argemone mexicana L., and Azadirachta indica A. Juss) had statistically lower Root Knot Index (RNI) than the control. The number of juveniles per 100 g soil was lower in soil amended with Dinbera retroflexa (Vahl), Azadirachta indica, Salvadora persica (L.), and Acacia nilotica than in unamended soil. The results of both RNI and number of juveniles were not significantly different from the synthetic nematicide used. Herbal powders from A. indica and Acacia nilotica may be promising in controlling of this pest because they are readily available to farmers in tropical regions.     

Restriction endonuclease mapping of the hepatitis B viral genome isolated from Taiwan

The Eco RI fragment of hepatitis B virus (HBV) DNA isolated from human blood plasma Dane particles were inserted into plasmid pUC8 Eco RI site and transformed into E. coli JM103 host. Two recombinants pTWL1 and pTWL2 were found to carry 3.2 kbp fragment and proved to have HBV genome by Southern hybridization method. The 1.4 kbp Bam HI fragment which carried the hepatitis B viral surface antigen (HBsAg) gene, obtained via Bam HI digestion of Dane particles DNA which was made fully double stranded by endogenous DNA polymerase reaction, was also inserted into plasmid pUC8 Bam HI site. Four recombinant clones, pTWS1, pTWS2, pTWS3, and pTWS4 were found. Only one of the clones pTWS1 carried the HBsAg gene in a correct orientation with respect to the lac promoter sequence. The physical mapping of HBV DNA was performed with several restriction endonucleases. Our results indicated that the HBV DNA insert contains unique XbaI and HpaI cleavage sites and lacks the cleavage sites for the HindIII, SmaI, KpnI, SalI, and SstI endonucleases. The locations of Bam HI, BglII, and HincII endonucleases cleavage sites within the cloned HBV DNA of the pTWL1 plasmid were similar to that HBV DNA of adw and adw2 subtypes.