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Biochemical Genetics (v.36, #11-12)
A KP Element Inserted Between the Two Promoters of the Alcohol Dehydrogenase Gene of Drosophila melanogaster Differentially Affects Expression in Larvae and Adults by Yan-Hong Wu; Ann Verona Wilks; John B. Gibson (pp. 363-379).
An allele of the Drosophila melanogaster alcoholdehydrogenase (Adh) gene has a 1.15-kb KP elementinserted, in the same orientation as Adh transcription,five nucleotides upstream of the distal transcription start site. The target site-GTCCAAGT — inAdh between nucleotides –13 and –6 isduplicated at both ends of the insertion. Adult flieswith either one or two copies of the allele have lessthan 12% of the alcohol dehydrogenase (ADH) activity of thecontrols. Activity levels are also reduced in larvae,but by a much smaller amount. Quantitative Northernanalyses showed that the low activity level in adults was caused by reduced transcript levels fromthe distal promoter. 5′ RACE experiments indicatedthat adult transcripts were mostly initiated downstreamof the distal promoter but some skipped the first adult exon. In late third-instar larvae thetranscripts present were from the proximal promoter.After the KP element was deleted by an appropriatebreeding program, the distal transcript increased inadults to the control level, but ADH activityincreased to only 50% of the control. No nucleotidechanges were found in the gene that could explain thisdifference.
Keywords: DROSOPHILA MELANOGASTER ; KP ELEMENT; TRANSCRIPTION
Randomly Amplified Polymorphic DNA Variation in Populations of Eastern Australian Koalas, Phascolarctos cinereus by E. V. Fowler; P. Hoeben; P. Timms (pp. 381-393).
Randomly amplified polymorphic DNA (RAPD)variation in populations of the koala, Phascolarctoscinereus, was investigated, revealing significantdifferences in the level of diversity between southernand northern regions of eastern Australia. Of the20 polymorphic RAPD markers identified in koalas, 4-7were polymorphic in southern populations, while 12-17were polymorphic in northern populations. Analysis of molecular variance revealed a significantdifference in the estimated variance between koalas fromnorthern and those from southern regions (P < 0.001),where populations from the north were greater than twice as variable as their southerncousins. The total genetic diversity observed wasattributed to regional differences (30.91%), populationdifferences within a region (11.77%), and differencesamong individuals within a population (57.32%). Forthe within-region analyses, a large proportion of thegenetic diversity was attributable to individualdifferences within a population, 80.34% for the north and 91.23% for the south. These resultsdemonstrate that RAPD markers are useful for determiningpopulation structure among koalas.
Keywords: GENETIC DIVERSITY; POPULATION STRUCTURE
Apolipoprotein E Polymorphism in Sheep by Kenji Tsunoda; Yoshio Yamamoto; Yukio Akiya; Keizo Sato; Heramba B. Rajbhandary; Ho Van Son; Chau Ba Loc (pp. 395-405).
Using polyacrylamide gel isoelectric focusingfollowed by immunoblotting with anti-humanapolipoprotein E (APO E) antibody, the geneticpolymorphism of APO E was determined from desialylatedplasma of 554 unrelated adults of four European sheep(Suffolk, Corriedale, Cheviot, and Finnish Landrace) andfive Asian local sheep (Bhyanglung, Baruwal, Kagi,Lampuchhre, and Vietnamese). Twenty phenotypesconsisting of the homozygous and heterozygous combinationsof two APO E variants within the seven variants (E1-E7)detected were identified. Family and population datasupported the hypothesis that the phenotypes are controlled by seven codominant alleles,designated APOE1 to APOE7, at asingle autosomal locus. The common alleles,APOE4, APOE5, and APOE7were observed at mean frequencies of 0.5763, 0.1471, and0.1921 in the European sheep group and 0.4920, 0.1123,and 0.2995 in the Asian local sheep group,respectively.
Keywords: APOLIPOPROTEIN E; GENETIC POLYMORPHISM; ISOELECTRIC FOCUSING; IMMUNOBLOTTING; DOMESTIC SHEEP
Expression and Export of Pseudomonas putida NTU-8 Creatinase by Escherichia coli Using the Chitinase Signal Sequence of Aeromonas hydrophila by Ming Chuan Hong; Jinq Chyi Chang; Mei Li Wu; Ming Chung Chang (pp. 407-415).
The gene for the creatinase from Pseudomonasputida NTU-8 was sequenced and revealed an open readingframe (ORF) of 1209 base pairs encoding a polypeptide of403 amino acids with a calculated molecular weight (Mr) of 45,691. The deducedamino acid sequence is very similar to that of thecreatinase of Pseudomonas putida andFlavobacterium sp. An overproduction system forthe chitinase signal peptide-creatinase hybrid gene was constructed by using the pQE-51expression vector in E. coli JM109. The amountof this fusion enzyme was about 50% exported into theperiplasmic space of E. coli.
Keywords: CREATINASE; SIGNAL PEPTIDE; PERIPLASMIC SPACE; PROTEIN OVEREXPRESSION
A New Esterase Gene Amplification Involved in OP Resistance in Culex pipiens Mosquitoes from China by C.-L. Qiao; M. Marquine; N. Pasteur; M. Raymond (pp. 417-426).
Two overproduced esterases (A8 and B8) notpreviously described were found in southern China. Theyprovide a low resistance level to organophosphate (OP)insecticides, and correspond to a coamplification of both esterase loci (Est-2 and Est-3)classically involved in OP resistance for this mosquitospecies. This coamplification is distinct from all othersimilar events thus far reported. The peculiar situation in southern China, where numerous OP resistancealleles at these two loci were found, is discussed incomparison with the Mediterranean situation, the onlyone with a similar diversity of overproducedesterases.
Keywords: INSECTICIDE RESISTANCE; ADAPTATION; ORGANOPHOSPHATE; OVERPRODUCTION; MOSQUITO