Mapping and characterisation of QTL × E interactions for traits determining grain and stover yield in pearl millet

A mapping population of 104 F(3) lines of pearl millet, derived from a cross between two inbred lines H 77/833-2 x PRLT 2/89-33, was evaluated, as testcrosses on a common tester, for traits determining grain and stover yield in seven different field trials, distributed over 3 years and two seasons. The total genetic variation was partitioned into effects due to season (S), genotype (G), genotype x season interaction (G x S), and genotype x environment-within-season interaction [G x E(S)]. QTLs were determined for traits for their G, G x S, and G x E(S) effects, to assess the magnitude and the nature (cross over/non-crossover) of environmental interaction effects on individual QTLs. QTLs for some traits were associated with G effects only, while others were associated with the effects of both G and G x S and/or G, G x S and G x E(S) effects. The major G x S QTLs detected were for flowering time (on LG 4 and LG 6), and mapped to the same intervals as G x S QTLs for several other traits (including stover yield, harvest index, biomass yield and panicle number m(-2)). All three QTLs detected for grain yield were unaffected by G x S interaction however. All three QTLs for stover yield (mapping on LG 2, LG 4 and LG 6) and one of the three QTLs for grain yield (mapping on LG 4) were also free of QTL x E(S) interactions. The grain yield QTLs that were affected by QTL x E(S) interactions (mapping on LG 2 and LG 6), appeared to be linked to parallel QTL x E(S) interactions of the QTLs for panicle number m(-2) on (LG 2) and of QTLs for both panicle number m(-2) and harvest index (LG 6). In general, QTL x E(S) interactions were more frequently observed for component traits of grain and stover yield, than for grain or stover yield per se.     

Identification and characterization of an amphipathic leucine zipper-like motif in Escherichia coli toxin hemolysin E. Plausible role in the assembly and membrane destabilization

Hemolysin E (HlyE) is a 34 kDa protein toxin, recently isolated from a pathogenic strain of Escherichia coli, which is believed to exert its toxic activity via formation of pores in the target cell membrane. With the goal of understanding the involvement of different segments of hemolysin E in the membrane interaction and assembly of the toxin, a conserved, amphipathic leucine zipper-like motif has been identified. In order to evaluate the possible structural and functional roles of this segment in HlyE, a 30-residue peptide (H-205) corresponding to the leucine zipper motif (amino acid 205-234) and two mutant peptides of the same size were synthesized and labeled by fluorescent probes at their N termini. The results show that the wild-type H-205 binds to both zwitterionic (PC/Chol) and negatively charged (PC/PG/Chol) phospholipid vesicles and also self-assemble therein. Detailed membrane-binding experiments revealed that this synthetic motif (H-205) formed large aggregates and inserted into the bilayer of only negatively charged lipid vesicles but not of zwitterionic membrane. Although both the mutants bound to zwitterionic and negatively charged lipid vesicles, neither of them inserted into the lipid bilayers nor assembled in any of these lipid vesicles. Furthermore, H-205 adopted a significant helical structure in membrane mimetic environments and induced the permeation of monovalent ions and release of entrapped calcein across the phospholipid vesicles more efficiently than the mutant peptides. The results presented here indicate that this H-205 (amino acid 205-234) segment may be an important structural element in hemolysin E, which could play a significant role in the binding and assembly of the toxin in the target cell membrane and its destabilization.     

Mixed culture bioconversion of 16-dehydropregnenolone acetate to androsta-1,4-diene-3,17-dione: optimization of parameters

Bioconversion of 16-dehydropregnenolone acetate (16-DPA) to androsta-1,4-diene-3,17-dione (ADD), an intermediate for the production of female sex hormones, by mixed culture of Pseudomonas diminuta MTCC 3361 and Comamonas acidovorans MTCC 3362 is reported. Various physicochemical parameters for the bioconversion of 16-DPA to ADD have been optimized in shake flask cultures. Nutrient broth inoculated with actively growing co-culture proved ideal for bacterial growth and bioconversion. A temperature range of 35-40 degrees C was most suitable; higher or lower temperatures adversely affected the bioconversion. Dimethylformamide below 2% concentration was the most suitable carrier solvent. Maximum conversion was recorded at 0.5 mg mL(-1) 16-DPA. A pH of 5.0 yielded a peak conversion of 62 mol % in 120 h incubation period. Addition of 9alpha-hydroxylase inhibitors failed to prevent further breakdown of ADD to nonsteroidal products. 16-DPA conversion in a 5 L fermenter followed a similar trend.     

Radical curative efficacy of five-day regimen of primaquine for treatment of Plasmodium vivax malaria in India

For over 4 decades the antimalarial program in India has been prescribing a 5-day primaquine regimen as an antirelapse therapy to treat Plasmodium vivax malaria. In view of conflicting reports on the effectiveness of this regimen in the Indian subcontinent, and the varying prevalence of P. vivax in various ecosystems in India, the antirelapse efficacy of this regimen was evaluated in Orissa, a malaria endemic state in eastern India where P. falciparum predominates. In 723 cases of P. vivax infection treated with chloroquine alone and followed up weekly for 1 yr, the prevalence of recurrence of parasitaemia with fever was 8.6%. Among another 759 P. vivax cases treated with chloroquine and a 5-day regimen of primaquine at 15 mg/day (adult dose), the recurrence of infection was 6.5%. The difference in recurrence was not significant (P = 0.53). It is important to note that in a great majority of cases of P. vivax in this area, infection did not recur even without treatment with primaquine. This finding, that the use of the 5-day primaquine regimen with chloroquine had no significant advantage over the use of chloroquine alone, undermines the rationale of using primaquine as an antirelapse drug in forested areas with a high prevalence of P. falciparum.     

Immunomodulation by peptide analogs of retroviral envelope protein

The mechanism by which retroviral proteins exert their immunosuppressive influence has remained enigmatic. Early studies have demonstrated that retroviral infection suppresses cellular and humoral immune responses. A hydrophilic 26 amino acid region of the otherwise hydrophobic transmembrane envelope protein of murine and feline leukemia viruses, p15E, is conserved among the transmembrane envelope proteins of numerous animal retroviruses (e.g. murine, feline, bovine and simian) as well as in human T-cell leukemia virus, and to a lesser extent, in human immunodeficiency virus (HIV). We evaluated the immunomodulatory properties of various synthetic retroviral envelope peptides synthesized as overlapping fragments to this conserved sequence. We report that two small peptides inhibit human mixed lymphocyte reaction (MLR), interleukin-2 (IL-2) and tumor necrosis factor (TNF-alpha) production. These peptides did not affect human natural killer (NK) cell cytotoxicity in vitro, and nitric oxide (NO) production in mouse macrophage cells, RAW264.7. Our observations suggests immunomodulatory potential of two retroviral peptide analogs.     

Effect of high altitude on sensitivity to the taste of phenylthiocarbamide

Sensitivity to the taste of phenylthiocarbamide (PTC) was studied using the Harris-Kalmus method in healthy human volunteers at sea level and then subsequently at an altitude of 3500 m over a period of 3 weeks, after which they were brought back to sea level. Blood sugar, insulin and blood cortisol levels were estimated weekly. The results indicated that, out of 51 subjects studied, 26 (55%) were PTC tasters at sea level. Eight of those unable to taste PTC at sea level tested as tasters at high altitude, and 2 of them reverted to being non-tasters on return to sea level. In the blood, an increase in cortisol and blood insulin levels was seen without any significant change in sugar levels. All the changes recorded at high altitude tended to return to basal values after re-induction to sea level. The study suggests that high-altitude hypoxia in some way, possibly involving changes in hormonal profile among other factors, causes an alteration in sensitivity to the taste of PTC, resulting in some of the individuals shifting to lower PTC sensitivity. Received: 24 November 1999 / Accepted: 25 January 2000     

Coronary stenting using a 6 F. diagnostic catheter: a report of two cases

Standard guiding catheters for coronary interventions may not selectively engage the coronary ostium despite a successful cannulation with a diagnostic catheter of the same curve. This discrepancy is explained by a slight difference in shape between the two catheters (shorter tip of the guiding, absence of tip tapering, etc.). The authors report on the use of 6 F. coronary diagnostic catheters as guiding catheters for coronary angioplasty and stent implantation in two patients with critical stenoses: in the right coronary artery distal to a right internal mammary artery anastomosis in one and in the ostial right coronary artery in the other. In both cases, the use of diagnostic catheters was the key to success despite the vessel orifice being unfavourable for the use of different types of guiding catheters.     

Synthesis of (3E, 5Z)-3,5-dodecadienylacetate, the sex pheromone of Phtheochroa cranaodes (Lepidoptera: Tortricidae

(3E, 5Z)-3,5-Dodecadienyl acetate, the female sex pheromone of Phtheochroa cranaodes, was regio and stereo-selectively synthesized from 1-octyne and (E)-4bromo-3-buten-1-ol by using Pd(PPh3)4, CuI and piperidine to afford the enyne (5). Further elaboration afforded the target pheromone. The synthetic pheromone was identified with the natural product by its MS and IR, data GLC retention time and biological activity.