Peanut clump virus and Polymyxa graminis interactions with pearl millet (Pennisetum glaucum [L.] R. Br.) and Sorghum(Sorghum bicolor [L.] Moench)

The susceptibility of 6 pearl millet (Ankoutess, ICMV IS 89305, ICMV IS 92222, ICMV IS 94206, Sadoré local and Zatib) and 6 sorghum (Irat 204, Mota Maradi, Nad 1, Sariaso 10, Sepon 82 and Zinder local) accessions to Peanut clump virus and its vector (Polymyxa graminis) was evaluated during the rainy season of 2002 under field conditions in Sadoré, Niger. The frequencies of infection of roots and leaves, analysed by a penicillinase-based DAS-ELISA, confirmed the differences among the pearl millet and sorghum accessions. In pearl millet, the virus was detected in roots and leaves, whereas in sorghum, infection was common in roots but rare in leaves. This was linked with the seed transmission of PCV in millet and not in sorghum. These results confirmed preliminary observations on the movement of the virus within these plant species, underlining the potential role of the viral P15 gene, a suppressor of post-transcriptional gene inactivation. Susceptibility to P. graminis f.sp. tropicalis was assessed under controlled conditions using a zoospore inoculation assay. Infection was quantified by a real-time quantitative PCR assay targeting the ribosomial DNA, and highlighting the differences between plant accessions and species. In addition to guidance on the selection of resistant cultivars, this study also sought to provide a toolbox for improving the understanding of the plant/vector/virus interaction

Indian peanut clump virus (IPCV) infection on wheat and barley: symptoms, yield loss and transmission through seed

Wheat and barley crops were susceptible to Indian peanut clump furovirus (IPCV) under field conditions in Hyderabad, Andhra Pradesh, India. In wheat, the Hyderabad isolate of IPCV (IPCV-H) induced symptoms resembling the rosette caused by soil-borne wheat mosaic furovirus, and these were apparent only 3 weeks after emergence. Early-infected plants were severely stunted and dark green, with chlorotic streaks on the youngest leaves, which turned necrotic as the plants aged; most of these plants died. Late-infected plants were also stunted and were conspicuous in the field because of their dark green appearance as a result of delayed maturity. The virus was detected by ELISA and nucleic acid hybridization in all plants with symptoms. These plants usually produced fewer tillers than healthy ones. Spikes were malformed, often did not emerge from the flag leaf, and they contained few, shrivelled seeds. Grain yield was decreased by an average of 58%. In barley, IPCV-H caused severe stunting and general leaf chlorosis. As the plants aged, the leaves became necrotic and the few infected plants that reached maturity produced small spikes. IPCV-H antigens were detected by ELISA in every wheat seed from infected plants and the virus was transmitted through wheat seed at a frequency of 0.5-1.3%. Storage at 4°C for more than a year did not affect seed transmission frequency. The virus was detected in leaves and roots of seed-transmitted plants. Seed transmission was not detected in barley. The Durgapura isolate (IPCV-D) was detected in wheat crops (cv. RR-21) at 3 different locations in Rajasthan State, India. Infected plants showed reduced growth without any overt symptoms

Conformation-specific spectroscopy and dynamics of biological neurotransmitters

Fundamental studies of flexible biological molecules in the gas phase are of great importance to the biological community. The focus of this work is the ultraviolet and infrared spectroscopy of the neurotransmitter serotonin. The conformational preferences of the monomer, protonated monomer, and water clusters are extensively studied. The conformation-specific ultraviolet and infrared spectra of the monomer and water clusters were compared to that of tryptamine and its water clusters as well as density functional theory to make firm conformational assignments of the eight conformations observed in the supersonic jet for the monomer and four conformations observed in the water clusters. The potential energy surface is also explored by determining energy barrier heights of isomerization from one conformational minimum to another in the monomer via stimulated emission pumping-population transfer and hole-filling spectroscopies. These results were also compared to the energy barriers previously found for tryptamine and the calculated density functional theory energy barriers. Two other biological molecules, tryptamine and melatonin, were studied by dispersed fluorescence where internal mixing of the first and second excited states was found for tryptamine

Etude de l'impact de la dilution du sperme sur la mesure automatique du spermogramme par analyseur d'image (cell-soft)

info:eu-repo/semantics/nonPublishe

STIMULATED EMISSION PUMPING-POPULATION TRANSFER SPECTROSCOPY OF JET-COOLED SEROTONIN

Author Institution: Department of Chemistry, Purdue University, West Lafayette, IN 47907Serotonin (5-hydroxytryptamine) possesses the same flexible ethylamine side chain as tryptamine, differing from it by the addition of a hydroxyl group in the 5-position on the indole ring. Conformational isomerization can therefore occur by reorientation of the ethylamine side chain, hindered rotation of the OH group, or a combination of the two. Building on our recently completed study of the conformation-specific spectroscopy of serotonin,}}. we report here the results of a study of the energy thresholds to isomerization in serotonin using stimulated emission pumping-population transfer (SEP-PT) spectroscopy. The method involves selective excitation of conformer X early in the supersonic free jet by SEP to produce ground state X with well-defined internal energy E. Following re-cooling of the excited molecules, conformer Y is interrogated selectively downstream in the expansion using laser-induced fluorescence. As the dump laser wavelength is tuned to higher vibrational levels in the ground state, the first transition that produces a gain in the population of conformer Y sets the energy threshold to X$\rightarrow$Y conformational isomerization. Energy thresholds for all seven A$\rightarrow$X channels are determined (where SERO(A) is the lowest energy conformer of serotonin), and compared against the corresponding signal in the A$\rightarrow$A reactant channel. The barriers that involve hindered rotation of the ethylamine side chain are generally similar to those in TRA, while the energy threshold to hindered rotation of the OH group is determined to be $569$\,<\,$E_{\mathrm{thresh}}$\,<\,$890$\,\wn. When conformational change involves motion of both sub-groups, the observed threshold is the larger of the two thresholds observed for the two sub-group isomerizations. These results will be compared to predictions of the relative energies of the minima and transition states from \textit{ab initio} theory

Evaluation in vitro de l'activité antagoniste d'isolats de Trichoderma harzianum Pers. contre trois espèces fongiques pathogènes de l'oignon au Burkina Faso

In vitro Evaluation of Antagonistic Activity of Trichoderma harzianum Pers. Isolates against Three Fungal Species Pathogens of Onion in Burkina Faso. The antagonistic effect of five Trichoderma harzianum Pers. isolates of which four from Burkina Faso and one from South Africa was evaluated in vitro against Aspergillus niger van Tieghem, Fusarium oxysporum f.sp. cepae Schlecht. Emend. Snyd & Hans and Fusarium solani (Mart.) Sacc. regarded as the main onion fungal pathogens in Burkina Faso. The fungal pathogens species and T. harzianum isolates were directly confronted in Petri dishes for seven days. The pathogen radial growth in presence or absence of antagonist was measured. The two isolates with the highest antagonism rates were grown with each pathogen in confrontation at distance. The culture took place in two Petri dishes sealed with parafilm for seven days. The radial growth of each pathogen was measured. All isolates of T. harzianum inhibited the fungal pathogens growth with antagonism ratio ranging from 0.61 to 0.93 and 0.01 to 0.24 respectively by direct and remote confrontation. The isolates ThTab from Burkina Faso and ThAfs from South Africa showed the best antagonism effect and a myco-parasitic action on all tested pathogens. The antagonistic action modes of these isolates and their possible biological control use are discussed