Ensifer, Phyllobacterium and Rhizobium species occupy nodules of Medicago sativa (alfalfa) and Melilotus alba (sweet clover) grown at a Canadian site without a history of cultivation.

Phage-resistant and -susceptible bacteria from nodules of alfalfa and sweet clover, grown at a site without a known history of cultivation, were identified as diverse genotypes of Ensifer, Rhizobium and Phyllobacterium species based on sequence analysis of ribosomal (16S and 23S rRNA) and protein-encoding (atpD and recA) genes, Southern hybridization/RFLP and a range of phenotypic characteristics. Among phage-resistant bacteria, one genotype of Rhizobium sp. predominated on alfalfa (frequency approximately 68 %) but was recovered infrequently ( approximately 1 %) from sweet clover. A second genotype was isolated infrequently only from alfalfa. These genotypes fixed nitrogen poorly in association with sweet clover and Phaseolus vulgaris, but were moderately effective with alfalfa. They produced a near-neutral reaction on mineral salts agar containing mannitol, which is atypical of the genus Rhizobium. A single isolate of Ensifer sp. and two of Phyllobacterium sp. were recovered only from sweet clover. All were highly resistant to multiple antibiotics. Phylogenetic analysis indicated that Ensifer sp. strain T173 is closely related to, but separate from, the non-symbiotic species 'Sinorhizobium morelense'. Strain T173 is unique in that it possesses a 175 kb symbiotic plasmid and elicits ineffective nodules on alfalfa, sweet clover, Medicago lupulina and Macroptilium atropurpureum. The two Phyllobacterium spp. were non-symbiotic and probably represent bacterial opportunists. Three genotypes of E. meliloti that were symbiotically effective with alfalfa and sweet clover were encountered infrequently. Among phage-susceptible isolates, two genotypes of E. medicae were encountered infrequently and were highly effective with alfalfa, sweet clover and Medicago polymorpha. The ecological and practical implications of the findings are discussed.

Agro-industrial waste materials and wastewater sludge for rhizobial inoculant production: a review.

Inoculating legumes with commercial rhizobial inoculants is a common agriculture practice. Generally, inoculants are sold in liquid or in solid forms (mixed with carrier). The production of inoculants involves a step in which a high number of cells are produced, followed by the product formulation. This process is largely governed by the cost related to the medium used for rhizobial growth and by the availability of a carrier source (peat) for production of solid inoculant. Some industrial and agricultural by-products (e.g. cheese whey, malt sprouts) contain growth factors such as nitrogen and carbon, which can support growth of rhizobia. Other agro-industrial wastes (e.g. plant compost, filtermud, fly-ash) can be used as a carrier for rhizobial inoculant. More recently, wastewater sludge, a worldwide recyclable waste, has shown good potential for inoculant production as a growth medium and as a carrier (dehydrated sludge). Sludge usually contains nutrient elements at concentrations sufficient to sustain rhizobial growth and heavy metals are usually below the recommended level. In some cases, growth conditions can be optimized by a sludge pre-treatment or by the addition of nutrients. Inoculants produced in wastewater sludge are efficient for nodulation and nitrogen fixation with legumes as compared to standard inoculants. This new approach described in this review offers a safe environmental alternative for both waste treatment/disposal and inoculant production.

Sequence and mutational analysis of the common nodBCIJ region of Rhizobium sp. (Oxytropis arctobia) strain N33, a nitrogen-fixing microsymbiont of both arctic and temperate legumes.

By heterologous hybridization, we have identified the common nodulation genes nodBCIJ of Rhizobium sp. strain N33 within a 8.2-kb PstI fragment. The nodBCIJ genes are located within a 4,620-bp region which also included a consensus nod box promoter. The four open reading frames coding for the nodBCIJ genes contain 657, 1,353, 915, and 789 nucleotides, respectively. We found that the nodA gene was not adjacent to the nodB gene, unlike the situation in many rhizobia. The DNA of the nodBCIJ genes of Rhizobium sp. strain N33 were found to be homologous to the corresponding genes of other rhizobia except for the 3'-coding region of the nodC gene. The deduced NodC protein was the longest of the rhizobia except Bradyrhizobium japonicum. Tn5 mutagenesis of the common nod region of strain N33 revealed that the nodBC genes were essential for nodulation on their temperate hosts Onobrychis viciifolia and Astragalus cicer. By contrast, mutations in the nodI and nodJ genes produced a Nod+ phenotype with a reduced number of nodules on the temperate hosts. Nodules formed on Onobrychis viciifolia by either nodI or nodJ mutants were approximately 10 times smaller than nodules formed by the wild type strain: this reduction in nodule size was not observed on Astragalus cicer.

A supermarket cardiovascular screening program: analysis of participants' solicitation of follow-up care.

We conducted a cardiovascular screening program in 54 supermarkets in the province of Québec, Canada to determine cardiovascular risk factors, including total cholesterol, blood pressure, tobacco use, height, weight, and physical activity levels. A 10-minute debriefing counseling session followed. Of the 3,432 screening participants 18-74 years of age, 2,420 participated in a nutrition study, consisting of answering a brief questionnaire before the screening. Three months after the screening, 1,293 individuals returned the posttest nutrition questionnaire sent to them by mail. We report follow-up care activity for low-risk and high-risk individuals for respondents of the posttest nutrition questionnaire. Overall, 53% of respondents reported seeing a physician within three months after the screening to discuss their blood cholesterol or blood pressure results, and the percentage ranged from 25% for individuals with normal cholesterol (< or = 199 mg/dL) and normal blood pressure (< 140/90 mm Hg) to 83% for individuals with high cholesterol (> or = 240 mg/dL) and high blood pressure (> or = 140/90 mm Hg). Respondents who saw a physician following the screening were more likely to be (1) those on medication at the time of the screening for high blood cholesterol and high blood pressure, (2) older individuals, (3) those found to have high blood cholesterol and high blood pressure values during the screening, (4) women, and (5) individuals with a lower level of education. Seventy-nine percent identified as having high blood cholesterol during the screening reported that their blood cholesterol was remeasured. The majority of high-risk participants and their physicians took appropriate follow-up action.(ABSTRACT TRUNCATED AT 250 WORDS)

Wastewater sludge as a substrate for growth and carrier for rhizobia: the effect of storage conditions on survival of Sinorhizobium meliloti.

The inoculation of legumes with rhizobia is used to maximise nitrogen fixation and enhance the plant yield without using N fertilisers. For this reason many inoculant types were developed and optimised. In our study, the effects of the growth medium, the carrier, the temperature and the storage period were determined on the survival of Sinorhizobium meloliti. Secondary sludge from Communauté Urbaine de Quebec wastewater treatment plant and standard medium (YMB) were used for rhizobial growth. Dehydrated sludge from Jonquière wastewater treatment plant, peat and a mixture of peat and sludge were used as carrier materials. Results showed that the wastewater sludge offered better protection for rhizobia survival during freezing and thawing at -20 degrees C than the standard medium. In general, results also showed the suitability of using sludge as a carrier because it had the same or a higher potential than peat to support survival of S. meliloti. In the case of YMB-grown rhizobia, peat- and sludge-based carriers appeared to be similar in terms of survival rate during the storage at 4 and 25 degrees C. For secondary sludge-grown rhizobia, the survival was better in sludge than in peat based carrier. Generally, the cell count remained higher than 10(8) cells/g for up to 80 days at 4 and 25 degrees C in both carriers (sludge and peat). However, for the secondary sludge-grown cells stored in peat-based carrier at 4 degrees C, the viable cells decreased under 10(8) cells/g at the 81st day of storage but remained acceptable compared to the standard (10(7) cells/g of carrier).

Changes in knowledge and food behaviour following a screening program held in a supermarket.

We examined the relationship between knowledge, health beliefs and dietary behaviours of participants in a supermarket cardiovascular screening program, the conceptual framework for which was the Health Belief Model. 3,432 individuals aged 18-74 participated in the screening program conducted in 54 supermarkets in Montreal and Quebec. This program identified participants' risk for cardiovascular disease by measuring total serum cholesterol, blood pressure, height, weight, level of physical activity, and tobacco use. A ten-minute debriefing counselling session interpreted risk factors and recommended follow-up. 70% (n = 2,420) also completed a nutrition questionnaire on knowledge, health beliefs, and frequency of consumption of high fat foods. Respondents increased their knowledge and reduced the frequency of consumption of high-fat foods following the screening program (p < or = 0.05), particularly individuals with higher blood cholesterol levels, high blood pressure, and women.

Growth of alfalfa in sludge-amended soils and inoculated with rhizobia produced in sludge.

The efficiency of rhizobial inoculants produced in wastewater sludge used as a growth medium and as a carrier was compared with that of inoculants produced in yeast mannitol broth (YMB) medium and by using peat as a carrier. Alfalfa (Medicago sativa L.) plants were inoculated with solid and liquid Sinorhizobium meliloti inoculants and grown in pots containing two soil types (Kamouraska clay soil and Saint-André sandy soil). The effect of various levels of sludge amendment (60 and 120 kg N/ha) and nitrogen fertilizer (60 kg N/ ha) was also studied. The sludge-based inoculants showed the same symbiotic efficiency (nodulation and plant yield) as YMB-based inoculants. The inoculation increased the nodulation indexes from 4-6 to 8-12, and the rhizobial number from 10(3) (uninoculated soils) to 10(6)-10(7) cells/g in inoculated soils. However, the shoot dry weights and the nitrogen contents were not increased significantly by the inoculation. Applying sludge as an amendment enhanced the rhizobial number in soils from 10(3) to 10(4) cells/g and improved significantly the plant growth (shoot dry weights and nitrogen contents). This improvement increased with sludge rate and with the cut (three cuts). Compared with sludge, N fertilizer gave lower plant yields. The nodulation was not affected by sludge and N-fertilizer application. The texture and physico-chemical properties of soil were found to affect the yield and nitrogen content of the plants. In this study, macroelements and heavy metals were at acceptable levels and were not considered to be negative factors.

[Enoximone in the hemodynamic evaluation before heart transplantation. A new test]. / L'énoximone dans le bilan hémodynamique prétransplantation cardiaque. Un nouveau test.

A better selection of patients referred for cardiac transplantation should lead to better surgical results. The presence of severe and irreversible pulmonary hypertension is an important factor and its pretransplantation assessment requires pharmacodynamic testing with vasodilators and dobutamine. The aim of this study of 10 patients in congestive cardiac failure referred for cardiac transplantation was to evaluate enoximone in this indication by comparing it with sodium nitroprussiate (3 micrograms/kg/mn). Intravenous enoximone (total dose of 1.5 mg/kg) increased the cardiac index (+49%; p less than 0.01), slightly reduced the mean systemic blood pressure (-8%; p less than 0.05) whilst inducing a greater reduction in systemic arterial resistances (-36%; p less than 0.01); the fall in mean blood pressure was less than with sodium nitroprussiate (-23%; p less than 0.01). Myocardial oxygen consumption (rate-pressure product) did not increase in contrast to the effect of dobutamine (+21%; p less than 0.01). There was a significant reduction in pulmonary arteriolar resistances (p less than 0.01) with all three drugs but the interpretation of this response and its prognostic significance in patients with a low cardiac output and persistent pulmonary hypertension are discutable even when pulmonary arteriolar resistances are less than 6 Wood units. The value of using an inotropic agent such as Dobutamine or Enoximone is to unmask fixed pulmonary hypertension which may be missed in patients with low cardiac output even with vasodilator drugs, and also to mimic the haemodynamic result of transplantation. In this indication Enoximone may be used like Dobutamine but with the advantage of not increasing myocardial oxygen consumption and being probably less arrhythmogenic.

Production of S. meliloti using wastewater sludge as a raw material: effect of nutrient addition and pH control.

The utilization of wastewater sludge as a raw material for the production of legume inoculant is considered as a new viable alternative for recycling. The effect of addition of nutrient sources (yeast extract and glycerol) and the pH control on S. meliloti was investigated in a shake flask and at controlled pH in a 15 l fermentor. Different concentrations of yeast extract (0.5, 1, 2 and 4 g l(-1)) and glycerol (2.5, 5, 7.5 and 10 g l(-1)) were added to the secondary sludge. The cell yield as well as the generation time were affected by the addition of these nutrient sources. The maximum cell yield (8.85x10(9) cfu ml(-1)) was achieved in 32 hours of incubation with the addition of 4 g l(-1) of yeast extract. This value was 3.2 times higher than from the non-supplemented sludge. Moreover, at this yeast extract concentration, the cell concentration in the stationary phase did not decrease. The addition of glycerol to sludge samples containing 4 g l(-1) of yeast extract further improved the rhizobial growth but not significantly compared with the control. The highest yield (16.5x10(9) cfu ml(-1)) was obtained with 7.5 g l(-1) of glycerol and 4 g l(-1) of yeast extract. In fermentor experiments, pH did not seem to be a limiting factor and the increase of pH up to 8.85 in uncontrolled fermentor seems to have no effect on rhizobial growth and cell yield.

Efficient and simple method for determination of suspendibility of bio-inoculant suspensions.

This study assessed the utilization of viscosity and zeta potential as a novel method to evaluate suspendibility of formulation of Sinorhizobium meliloti grown in starch industry wastewater for use as bio-inoculants. For this objective, sorbitol was used as a suspending agent at concentrations of 0 to 10% w/v. Model, based on multiple linear regression (with pH as dependant variable, and zeta potential, average particle size and sorbitol concentration as independent variables) demonstrated an important relation which was significant (p<0.001, R2=0.98). Sigmoid regression revealed a significant relation between zeta potential and suspendibility with p value=0.007 and R-squared=0.86, and between viscosity and suspendibility (p value<0.0001 and R squared=0.9823). Thus, these direct correlations established the lowering of measurement time from 12 h to 5 min.