The transfer of pyrethroid resistance resulting from crosses between resistant German cockroaches and susceptible Asian cockroaches

Crosses were made between the Asian cockroach,Blattella asahinai Mizukubo, and resistant strains of the German cockroach,B. germanica (L.), to assess the transfer of pyrethroid resistance to the progeny and to study the inheritance mechanism(s) involved. It was shown that the strain of Asian cockroaches studied was susceptible to four pyrethroids. F₁ progeny were essentially susceptible to the same compounds. Tests with F₂ progeny and those from backcrosses to the resistant parent indicated that the data for each pyrethroid fit an hypothesis of simple, autosomal, nearly completely recessive inheritance. The results are discussed from the standpoint of the impact of the Asian genome on the inheritance mechanism(s).     

GTPγS restores nucleophosmin (NPM) localization to nucleoli of GTP-depleted HeLa cells

Previous studies showed that localization of nucleophosmin/B23 (NPM) to nucleoli requires adequate cellular GTP levels (Finchet al., J Biol Chem 268, 5823–5827, 1993). In order to study whether hydrolysis of GTP plays a role in NPM localization, we introduced a nonhydrolyzable GTP analog into HeLa cells. Cells were first depleted of GTP with the IMP dehydrogenase inhibitor, mycophenolic acid (MA), to induce translocation of NPM from the nucleoli to the nucleoplasm. Non-hydrolyzable GTP analogs were then introduced into cells by electroporation. We found that introduction of the non-hydrolyzable analog, GTPS, was effective in restoring NPM localization to nucleoli. Cells incubated in medium containing G-nucleotides without electroporation showed no effect. To reduce the possibility that cells use guanine from degraded nucleotide to supplement GTP pools via salvage pathways, experiments were also performed in the presence of (6-mercaptopurine) 6MP, a competitive inhibitor of the salvage enzyme, HGPRT (hypoxanthine guanine phosphoribosyl transferase), in addition to MA. Under these conditions, introduction of GTPS still effectively restored the localization of NPM into nucleoli. This study demonstrates that electroporation can be used effectively to introduce nucleotides into cultured cells without excessive loss of viability. Our results also indicate that the GTP dependent localization of NPM to the nucleoli may not require GTP hydrolysis.     

Long-Term Drug Treatment of Obesity in a Private Practice Setting

ATKINSON, RICHARD L, ROY C BLANK, DONALD SCHUMACHER, NIKHIL V DHURANDHAR, DOUGLAS L RITCH. Long-term drug treatment of obesity in a private practice setting. This study evaluated the long-term efficacy and safety of the combination of phentermine and fenfluramine for the treatment of obesity in a private practice setting. A total of 1388 consecutive, qualified patients presenting to a private general internal medicine practice in Charlotte, NC, were enrolled with eligibility criteria including: age 18 years to 60 years, 20% over “desirable” bodyweight or body mass index <27, no serious medical or psychiatric disease, and no contraindications to drug therapy. Patients were instructed in diet, exercise, and behavior modification techniques and received phentermine (15 mg/day to 30 mg/day) and fenfluramine (20 mg/day to 60 mg/day) continuously for over 3 years. Average duration of treatment was 15. 9 months, and average weight loss at the last visit was 11. 6 kg, or 11. 7% of initial bodyweight. For patients completing 1 year of drug treatment, mean weight loss was 16. 5 kg, or 16% of initial weight. Weight loss persisted for 2 years, but partial regain was seen at 3 years. The dropout rates were 18% at 6 months, 39% at 1 year, 68% at 2 years, and 78% at 3 years. At 1 year, blood pressure of hypertensive patients fell from 151/95 mm Hg to 127/78 mm Hg, and serum cholesterol and triglycerides of hyperlipidemic patients fell by 0. 750 mmol/L (29 mg/dL) and 0. 937 mmol/L (83 mg/dL), respectively. Adverse events were modest. We conclude that, in a private practice setting, long-term treatment of obesity with the combination of phentermine, fenfluramine, and a weight maintenance program is generally safe and effective. More research is needed to determine efficacy and safety for longer than 3 years.     

Amino acid concentrations and selected enzyme activities in rat auditory,olfactory, and visual systems

Homogenates of specific brain regions of three sensory systems (auditory, olfactory, and visual) were prepared from pigmented Long-Evans Hooded rats and assayed for amino acid concentrations and activities of glutaminase, aspartate aminotransferase (total, cytosolic, and, by difference, mitochondrial), malate dehydrogenase, lactate dehydrogenase, and choline acetyltransferase. Comparing the quantitative distributions among regions revealed significant correlations between AAT and aspartate, between glutaminase and glutamate, between glutamate and glutamine, and between AAT plus glutaminase, or glutaminase alone, and the sum of aspartate, glutamate, and GABA, suggesting a metabolic pathway involving the synthesis of a glutamate pool as precursor to aspartate and GABA. Of the inhibitory transmitter amino acids, GABA concentrations routinely exceeded those of glycine, but glycine concentrations were relatively high in brainstem auditory structures.     

Two cDNA clones coding for the legumin protein of Pisum sativum L. contain sequence repeats

The sequence of two cDNA clones coding for the whole of the -subunit and most of the -subunit of legumin are presented together with a considerable amount of protein sequence data to confirm the predicted amino acid sequence. A unique feature shown by these cDNAs is the presence of three 56 base pair tandem repeats in the region encoding the C terminal of the polypeptide. The tandem repeats are also exhibited in the predicted polypeptide sequence as three 18 amino acid repeats which contain extremely high proportions of polar, mainly acidic, residues. The new sequences are compared to the previously published sequence of some shorter legumin cDNAs (Nature 295: 76–79). In the region where the sequences overlap, the previous cDNAs differ from the new ones by only a few base substitutions but most of the repeated region is not present though the sequences on either side are. The possibility that the absence of the repeats may reflect the difference between two types of legumin gene, rather than an artefact of the cloning of the cDNAs, is discussed.     

Fractionation of the gene-size macronuclear chromatin fragments of the binucleated eukaryote Oxytricha

Summary The macronuclear chromatin of Oxytrichia nova consists of chromatin fragments which are fully soluble in 0.2 mM EDTA and whose DNA length varies from 500–25 000 bp. The DNA migrates electrophoretically as a series of discrete bands, with specific genes present in only one or a few bands. The chromatin fragments are composed of nucleosomes and migrate electrophoretically in proportion to their DNA length. These results suggest schemes for the fractionation of undigested chromatin in order to enrich for specific genes, facilitating analysis of changes in chromatin structure associated with changes in gene expression.     

Characterization of temperate phages ofBacillus subtilis

Nine known temperature phages ofBacillus subtilis, including four that are newly isolated (ϱ6, ϱ10, ϱ14, and ϱ18), have been compared. Analysis by serology, immunity, host range, and adsorption site similarity place the phages into four groups: Group I, ϕ105, ϱ6, ϱ10, and ϱ14, which are 80–90% related; Group II, SPO2; Group III, ϕ3T and ϱ11, 100% related; and Group IV, SP16. The phage ϱ18 is largely uncharacterized, but is heteroimmune to other groups.     

Variation in the susceptibility of sockeye salmon Oncorhynchus nerka to infectious haemopoietic necrosis virus

Haemoglobin concentrations, haematocrit values, red blood cell counts, red blood cell diameter, erythrocyte sedimentation rate and plasma haemoglobin concentration were measured on the air-breathing mud eel Amphipnous cuchia .