In vitro metabolism of EPN and EPNO in susceptible and resistant strains of house flies

EPN is twice as toxic as EPNO to house flies from both the Diazinon-resistant strain and the susceptible strain. EPN and EPNO are also eight times more toxic to the susceptible than the resistant strain. This is due to the ability of the resistant strain to metabolize these compounds to a greater extent. Metabolism by the glutathione S-transferases present in the 100,000g supernatant is more extensive than that by the NADPH-dependent microsomal mixed-function oxidases. The glutathione S-transferases are the major route of metabolism for EPN and appear to be the principal mechanism conferring resistance. EPN was metabolized by the microsomal fraction via oxidative desulfuration to the oxygen analog, EPNO, and by oxidative dearylation to p-nitrophenol. EPNO was metabolized by the same system to p-nitrophenol and desethyl EPNO as well as to an unknown metabolite. The soluble fraction metabolized EPN to p-nitrophenol, S-(p-nitrophenyl)glutathione, O-ethyl phenylphosphonothioic acid, and S-(O-ethyl phenylphosphonothionyl)glutathione. The identification of the latter conjugate demonstrates a new type of metabolite of organophosphorus compounds. EPNO was metabolized by the soluble fraction to p-nitrophenol and S-(p-nitrophenyl)glutathione.     

Temperature in relation to phosphorus nutrition in Chinese cabbage

Chinese cabbage plants [Brassica pekinensis (Lour) Rupr. cv. Nagaoka 50] were cultivated experimentally for two years (1993 and 1994) using a semi‐forcing technique of floating rowcovers, polyethylene (T₁), polypropylene (T₂), versus no floating row‐covers, control (T₀). Five samplings were made, taking four plants per each replication and total phosphorus (P) (P_total), inorganic P (P_i), and calculated organic P (P_org) were determined as well as foliar acid phosphatase activity (FAPA). The aerial and root temperatures of the treatments T₁ and T₂ exceeded those of T₀. The P_total concentration showed no significant variations with treatment, whereas the P_i concentrations increased in T_i and T₂ and P_org decreased in both treatments with respect to T₀. The FAPA was influenced a similar way as P_i, raising with temperature. The contents (mg plant^‐1) of P_tolal, P_i, and P_org were greater in T₁ and T₂ than in T₀, and this could be due to the fact that the highest temperatures (root and aerial zone) generated by the plastic rowcovers favored the absorption of P, thereby boosting FAPA and the fresh and dry weights, and yield.     

Genetic mapping,marker assisted selection and allelic relationships for the Pu6 gene conferring rust resistance in sunflower

Rust resistance in the sunflower line P386 is controlled by Pu₆, a gene which was reported to segregate independently from other rust resistant genes, such as R₄. The objectives of this work were to map Pu₆, to provide and validate molecular tools for its identification, and to determine the linkage relationship of Pu₆ and R₄. Genetic mapping of Pu₆ with six markers covered 24.8 cM of genetic distance on the lower end of linkage Group 13 of the sunflower consensus map. The marker most closely linked to Pu₆ was ORS316 at 2.5 cM in the distal position. ORS316 presented five alleles when was assayed with a representative set of resistant and susceptible lines. Allelism test between Pu₆ and R₄ indicated that both genes are linked at a genetic distance of 6.25 cM. This is the first confirmation based on an allelism test that at least two members of the R_adv/R₄/R₁₁/ R_13a/R_13b/Pu₆ cluster of genes are at different loci. A fine elucidation of the architecture of this complex locus will allow designing and constructing completely new genomic regions combining genes from different resistant sources and the elimination of the linkage drag around each resistant gene.     

Soil carbon dioxide efflux in pure and mixed stands of oak and beech

Total Soil Respiration (TSR) was measured in pure and mixed stands of oak and beech and was partitioned into two contributions using the forest floor removal technique: Mineral Soil Respiration (MSR) and Forest Floor Respiration (FFR). In addition, laboratory incubations of the forest floor and the Ah horizon were performed to evaluate the heterotrophic respiration and the DOC production of these horizons. The relationships between soil temperature and the various soil respiration contributions in the three stands were compared using Q ₁₀ functions. In situ, significant differences (α = 0,05) between stands were observed for the R ₁₀ parameter (respiration rate at 10 °C) of the TSR, MSR and FFR contributions, while only the temperature sensitivity (Q ₁₀) of TSR was significantly affected by stand composition. The effect of soil water content was only significant on MSR and followed different patterns according to stand composition. Under controlled conditions, the R ₁₀ of the forest floor and of the Ah horizon varied with stand composition and the Q ₁₀ of the forest floor decreased in the order: oak (2.27) > mixture (2.01) > beech (1.71).     

Integrated pest management of Tuta absoluta: practical implementations across different world regions

Journal of Pest Science - The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato...     

RFLP mapping of QTLs for photoperiod response in tropical sorghum

Genetic control of flowering time in sorghum was investigated using a recombinant inbred lines population derived from a cross between IS 2807, a slightly photoperiod sensitive tropical caudatum landrace, and IS 7680,a highly photoperiod sensitive tropical guinea landrace. Progenies were sown with their parents at six different dates between 1995 and 1997 in Burkina Faso. Direct field measures and synthetic measures derived from the implementation of a model were used to characterize the photoperiod response. Emphasis was put to identify the most relevant traits to account for Basic Vegetative Phase (BVP) and photoperiod sensitivity sensus stricto. One QTL was detected on Linkage Group (LG) F for the traits related to BVP. Two QTLs were detected on LGs C and H for the traits related to the photoperiod sensitivity sensus stricto. This gives credit to at least partially independent genetic determinisms for those two components of photoperiod response. Evidences for possible orthology of the QTLs detected here with other QTLs and major genes involved in flowering time of sorghum and rice are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Intra‐household constraints on educational attainment in rural households in Papua New Guinea

This paper examines intra‐household and socio‐cultural factors leading to differential outcomes in educational attainment by gender and birth order amongst smallholder oil palm households in Papua New Guinea. Not all children share equitably in the household resources allocated to education: females have lower average education levels than males, and high birth order children have higher education attainment than lower birth order siblings, indicating preferential parental investment in sons and early born children. The findings demonstrate that despite households having regular access to relatively high incomes from oil palm and residing in close proximity to schools, primary school net enrolment rates remain significantly lower than those for East Asia and the Pacific region, and the millennium development goal of universal primary education has not been met. This finding is likely to be the result of a combination of intra‐household factors including gender power imbalances, low parental education levels, the agency of youth in educational decision‐making and the weakening attraction of education as a means of improving income‐earning potential.     

Diagnosis and surgical removal of brain abscesses in a juvenile alpaca

CASE DESCRIPTION: A 1-month-old female alpaca was examined because of progressive clinical signs consistent with an intracranial lesion. CLINICAL FINDINGS: Clinical signs included signs of depression, lethargy, tetraparesis, and neck weakness. Two large isointense intracranial masses could be seen on T1-weighted magnetic resonance images. On T2-weighted images, the masses contained concentric rings of hypointense and hyperintense material. TREATMENT AND OUTCOME: 2 abscesses were removed via a craniotomy that incorporated removal of the sagittal crest and surrounding skull and transection of the sagittal sinus. The bony deficit was replaced with polypropylene mesh. The alpaca recovered within 2 weeks and was fully integrated into the herd within 1 month after surgery. CLINICAL RELEVANCE: Findings indicated that surgical removal is a feasible means of successfully treating intracranial abscesses in juvenile alpacas.     

Euthanasia of honey-bee colonies: Proposal of a standard method

Honey bees are most often kept for production purposes. Sanitary, regulatory, or zootechnical circumstances may lead the beekeeper or the veterinarian to dispose of a honey-bee colony. Unfortunately and at present, no standard method of euthanasia exists, leaving the door open to many more or less acceptable practices. Based on a short survey of current practices in 8 countries, we list and rank these methods. Although imperfect, the sulfur dioxide technique appears to be the most efficient. We suggest that it should become the reference method to be taught and incorporated into veterinary and regulatory guidelines.     

The molecular mechanism of thermal noise in rod photoreceptors

Spontaneous electrical signals in the retina's photoreceptors impose a limit on visual sensitivity. Their origin is attributed to a thermal, rather than photochemical, activation of the transduction cascade. Although the mechanism of such a process is under debate, the observation of a relationship between the maximum absorption wavelength (λ(max)) and the thermal activation kinetic constant (k) of different visual pigments (the Barlow correlation) indicates that the thermal and photochemical activations are related. Here we show that a quantum chemical model of the bovine rod pigment provides a molecular-level understanding of the Barlow correlation. The transition state mediating thermal activation has the same electronic structure as the photoreceptor excited state, thus creating a direct link between λ(max) and k. Such a link appears to be the manifestation of intrinsic chromophore features associated with the existence of a conical intersection between its ground and excited states.