Host range of tropical and sub-tropical isolates of Polymyxa graminis

The host range of Polymyxa graminis isolates originating from peanut clump-infested areas in India (Andhra Pradesh and Rajasthan), Pakistan and Senegal was studied on monocotyledonous and dicotyledonous cultivated species, using known quantities of sporosori as inoculum. Profuse multiplication occurred only on some graminaceous species, but the various isolates showed different host specificity. All the isolates produced high infection on sorghum and pearl millet, and all but one isolate from Rajasthan infected maize. Wheat, rye and barley were susceptible to some of the tested isolates. The isolates from Rajasthan and Pakistan produced moderate to severe infection on at least one of these species. On rice, groundnut and sugar beet, only traces of infection by some isolates were detected, whereas no infection was observed on mustard and sunflower. Differences of susceptibility in Pennisetum spp. and Sorghum spp. were demonstrated. The variations in host specificity among isolates from peanut clump-infested areas may result from an adaptation of P. graminis populations to various biotopes. The implications of these results for the management of peanut clump disease are discussed. A comparison of the host ranges of isolates of P. graminis and P. betae from temperate areas demonstrated that distinct types of Polymyxa might be identified based on their relative ability to multiply on susceptible species. Nevertheless, overlapping in the host ranges among the different Polymyxa types, characterised by distinct ecological and genomic features, raises doubts about the host range as a classification criterion for the Polymyxa genus

High temperature during storage favours infection potential of resting spores of Polymyxa graminis of Indian origin

The infection potential of sporosori of Polymyxa graminis involved in the transmission of the Indian peanut clump virus (IPCV) was assessed by culturing bait plants exposed to various concentrations of sporosorus suspensions and then determination of the numbers of plants that became infected. Storage of air-dried inoculum at temperatures above 30 degrees C resulted in an increase in the infection potential compared to that of sporosori stored at 15 degrees C or 20 degrees C. In contrast, when the sporosori were stored at 20 degrees C or freeze-dried, their infection potential was low. These results confirm the adaptation of P. graminis isolates associated with IPCV transmission to the tropical environment. The implication of storage temperature for the epidemiology of Indian peanut clump virus and for the assessment of the infection potential of the vector in the soil is discussed

Differences in temperature requirements between polymyxa sp. of Indian origin and Polymyxa graminis and Polymyxa betae from temperate areas

The temperature requirements of three single cystosorus strains of Polymyxa sp. from India were studied at 15-18, 19-22, 23-26 and 27-30 degrees C (night-day temperature), and compared with the temperature requirements of three strains of P. graminis from Belgium, Canada and France and two strains of P. betae from Belgium and Turkey Sorghum was used as the host-plant for the Indian strains; the strains of P. graminis and P. betae from temperate areas were cultivated on barley and sugar beet, respectively. The cystosori germination and the development of plasmodia, zoosporangia and cystosori of Polymyxa sp. from India were optimal at 27-30 degrees C. Infection progression was slower at 23-26 degrees C than at 27-30 degrees C. At 19-22 degrees C, infection was insignificant. No infection occurred below 19 degrees C. In contrast, the infection of barley with P. graminis strains from temperate areas was optimal at 15-18 degrees C, but at 19-22 degrees C the progression appeared inconsistent and infection stayed low. Above 22 degrees C, infection was insignificant. P. betae strains showed consistent infection in the range of 15-18 degrees C to 27-30 degrees C. Plasmodia formation and cystosori detection of the Belgian strain were slightly advanced at 23-26 degrees C compared to 19-22 degrees C but clearly restrained at 27-30 degrees C. Fungus development of the P. betae strain from Turkey was almost as high at 27-30 degrees C as at the lower temperatures. These results strengthen the case for distinguishing between Polymyxa sp. from India and P. graminis or P. betae from temperate areas

Characterization of Polymyxa graminis involved in the transmission of peanut clump virus in tropical areas

The plasmodiophoraceous fungus, Polymyxa graminis Ledingham, is involved in the transmission of Peanut clump virus (PCV), a soil borne virus widely distributed in India and in West Africa. This fungus is known in temperate aras to be the vector of soil-borne viruses on barley, wheat and oat. Ecological requirements of P. graminis isolates from various origins are possibly different. Indian and African isolated indeed grow easily at 25-30°C°, whereas those from temperate areas are favoured by temperatures between 15 and 20°C. Host range of tropical isolates is apparently wider and less specific than that of isolates from temperature areas. Indian P. graminis isolates grow on monocotyledonous plants as well as on dicotyledonous plants, whereas in temperature areas, two fungal species are listed as separate species according to the host specificity; P. graminis growing only on graminaceous plants and Polymyxa betae Keskin on Chenopodiaceae. In order to clarify the taxonomic position and precise the requirements of P. graminis associated with PCV transmission, pure strains obtained from a single cystosorus are prepared from isolates of various origins. Host range, ecological requirements, such as temperature optimum and pH, are studied. First results confirm differences in the temperature optimum, the Indian strain growing best on sorghum between 20 and 30°C compared to less than 20°C for the strains from northern origins on barley

Comparative effects of chloride and sulfate salinities on two contrasting rice cultivars (Oryza sativa L.) at the seedling stage

In field conditions, soil salinity may be due to an excess of different soluble salts. In order to compare the impact of chloride and sulfate salinities on rice, two contrasted cultivars (IKP: salt-sensitive and Pokkali: salt-resistant) were exposed to iso-strength Na+ nutrient solutions (NaCl 50 mM or Na2SO4 25 mM; EC: 5.31 dS m−1) for 2 weeks under controlled environmental conditions. It was found that NaCl was more toxic than Na2SO4, especially for the salt-sensitive IKP. Sodium and proline accumulation were higher while shoot osmotic potential was lower in NaCl-treated plants than in those exposed to Na2SO4. Chloride-treated plants exhibited a higher shoot malondialdehyde concentration, suggesting a higher level of lipid peroxidation while Na2SO4-treated plants presented a slightly higher total antioxidant activity. Pokkali was more tolerant than IKP to both types of toxicities although it accumulated similar concentration of toxic ions. Pokkali was able to reduce the root osmotic potential and to quickly recycle oxidized glutathione to reduced glutathione, which may help the plant to more efficiently control its oxidative status in stress conditions. It is concluded that different salts may have distinct impacts on the plant physiology and that differences may vary according to the considered cultivar

Differential risk factors for early and later hospital readmission of older patients.

BACKGROUND AND AIMS: This study aimed at analyzing rates and factors associated with early and later readmission (0-1 month and 2-3 months after discharge, respectively) of older people after index hospitalization. METHODS: This prospective observational study was conducted in two teaching hospitals. People 70 years and over were interviewed within 48 h of emergency admission. Socio-demographic and medical factors were collected, together with functional factors including Activities of Daily Living (basis and instrumental), cognitive state, and geriatric syndromes. Medical diagnosis, length of stay, and destination were collected at discharge, and patients were followed up by phone 1 and 3 months after discharge. During these interviews, outcomes on readmission, institutionalization, need for help, and death were evaluated. RESULTS: The population of 625 patients had a mean age of 80.0 years. The rate of early readmission (01 month) was 10. 7% and the overall rate within 3 months was 23.1%. Logistic regression analysis showed that variables predicting early readmission were previous hospitalization within 3 months, a longer length of stay, and a discharge diagnosis in chapter 8 (respiratory system) and chapter 10 (genito-urinary system) of the ICD-9-CM. Variables predicting later readmission were previous hospitalization within 3 months, a discharge diagnosis in chapter 7 (circulatory system) of the ICD-9-CM, and a poor pre-admission IADL score. CONCLUSIONS: In a medicalized population of older people, several risk factors may be identified for 0-1 month and 2-3 month readmission. Besides severe morbidities at discharge, diagnoses and previous hospitalization, pre-admission IADL was an independent risk factor for 2-3 month readmission

The cytokinin trans-zeatine riboside increased resistance to heavy metals in the halophyte plant species Kosteletzkya pentacarpos in the absence but not in the presence of NaCl

Heavy metals such as cadmium and zinc constitute major pollutants in coastal areas and frequently accumulate in salt marshes. The wetland halophyte plant species Kosteletzkya pentacarpos is a promising species for phytostabilization of contaminated areas. In order to assess the role of the antisenescing phytohormone cytokinin in heavy metal resistance in this species, seedlings were exposed for two weeks to Cd (10 mM), Zn (100 mM) or Cd þ Zn (10 mM þ 100 mM) in the presence or absence of 50 mM NaCl and half of the plants were sprayed every two days with the cytokinin trans-zeatine riboside (10 mM). Zinc reduced the endogenous cytokinin concentration. Exogenous cytokinin increased plant growth, stomatal conductance, net photosynthesis and total ascorbate and reduced oxidative stress estimated by malondialdehyde in Zn-treated plants maintained in the absence of NaCl. Heavy metal induced an increase in the senescing hormone ethylene which was reduced by cytokinin treatment. Plants exposed to the mixed treatment (Cd þ Zn) exhibited a specific hormonal status in relation to accumulation of abscisic acid and depletion of salicylic acid. Non-protein thiols (glutathione and phytochelatins) accumulated in response to Cd and Cd þ Zn. It is concluded that toxic doses of Cd and Zn have different impacts on the plant behavior and that the simultaneous presence of the two elements induces a specific physiological constraint at the plant level. Salinity helps the plant to cope with heavy metal toxicities and the plant hormone cytokinin assumes key function in Zn resistance but its efficiency is lower in the presence of NaCl

Identification précoce du profil gériatrique en salle d'urgences: Présentation de la grille SEGA

Context: The number and proportion of frail elder patients admitted to hospital without warning, often via casualties, are increasing. Early identification of geriatric profile and associated risks should contribute both to improving the orientation to appropriate services and to the rapid initiation of necessary interventions in order to prevent functional complications and prepare discharge so as to avoid prolonged stays. Methods: We developed a tool called SEGA, which evaluates the geriatric profile of older patients admitted in casualty. From data found in relevant literature, the advice of experts and the data from the cohort Declic, the tool was used prospectively in the casualty ward of a Belgian university hospital. Results: The utilisation of SEGA was judged feasible in this context. Approximately, ten minutes are necessary to supply data. The final score is closely linked to several predictors of geriatric frailty. Conclusion: The tool is easy to use in the context casualty admissions and could contribute to improving the management and orientation of frail older adults admitted to emergency department