Biopriming of maize seeds with plant growth-promoting bacteria isolated from the earthworm Aporrectodea molleri: effect on seed germination and seedling growth.

Earthworms have become a potential source of multi-beneficial bacteria and effective bioinoculants. Seed biopriming is an efficient inoculation method to apply bacteria prior to sowing, which enhances the chances of bacterial candidates to colonize the rhizosphere and/or establish a liaison with the plant. In this study, we evaluated plant growth-promoting traits of bacterial strains isolated from the earthworm's Aporrectodea molleri chloragogenous tissue. In addition, we investigated their prospective use as biopriming agents to enhance Zea mays germination and seedling growth. Results were subjected to principal component analysis for potential correlations between the studied parameters. The bacterial strains displayed different in vitro plant growth-promoting characteristics and were efficient when applied in vivo as they significantly increased maize germination rate (26-78%), root elongation (67-84%), seedlings fresh weight and dry weight. Aeromonas encheleia TC22 was the most significant strain to influence germination due to its high ability to produce indole-3-acetic acid, and along with Pseudomonas azotoformans TC1, they were the most proficient at enhancing seedling root elongation and biomass, which was significantly correlated with their in vitro plant growth-promoting traits. Our findings indicate that isolates TC22 and TC1 are potent bio-primers for maize seeds and should be tested further for their use as biopriming inoculants.

[Low prevalence of anti-centromere antibodies in scleroderma in Morocco (about 272 cases)]. / Faible prévalence des anticorps anti-centromère dans la sclérodermie au Maroc (à propos de 272 cas).

PURPOSE: assessment of autoantibodies prevalence during scleroderma within a Moroccan population by a retrospective survey. MATERIAL AND METHODS: 272 patient (220 cases of systemic sclerosis, 45 cases localised scleroderma and 7 cases of mixed connective tissue disease (MCTD)) underwent a screening for antinuclear antibodies (ANA) by indirect immunofluorescence (IFI) on Hep-2 cells, followed, in 127 cases, by anti-extractable nuclear antigen (ENA) antibodies identification using a double immunodiffusion (IDD) method. RESULTS: sixty eight for percent of patients presenting with a systemic sclerosis had positive ANA whose identification revealed: 23 cases (15.3%) of anti-topoisomerase I, 8 cases (5.3%) of anti-centromere (ACA) and 5 cases (3.3%) of anti-U1-RNP antibodies. Out of the 8 cases of ACA, 3 corresponded to a CREST syndrome. Anti-topoisomerase I antibodies were observed in 2 of the 4 patients having an interstitial pulmonary syndrome. Anti-U1-RNP antibodies were present in 3/38 patients (7.8%) having a systemic sclerosis associated to arthritis. 4/45 patients (9%), presenting with a localised scleroderma, had positive ANA, of which 2 were ACA. All patients admitted for MCTD had anti-U1-RNP antibodies, coexisting with anti-Sm antibody in 2 cases. CONCLUSION: the low prevalence of ACA observed in this survey, when compared to American, European and Japanese studies, is probably due to ethnic variation in frequency of ANA. Indeed, low rates or absence of ACA have been reported in south-African, Afro-American, Indian, and Thai studies. The IDD, method of reference for detecting of anti-ENA antibodies, identify a small fraction of anti-nucleolar aspects of scleroderma. Thus, other methods such as ELISA and/or immunoblotting are required to complete their identification.

[In vitro antibiosensitivity of different strains of Mycoplasma capricolum]. / Antibiosensibilité in vitro de diverses souches de Mycoplasma capricolum.

The in vitro sensitivity of 20 wild strains of M. capricolum and that of the reference strain (California kid) against 14 antibiotics was investigated by means of a micromethod. The technique is based on the determination of the inhibitory minimum concentration (IMC) in a liquid medium as revealed by the inhibition of glucose metabolism. The following results were obtained: all strains were sensitive to five antibiotics (tylosin, oxytetracyclin, gentamycin, neomycin, nalidixic acid) with an IMC varying from 0.06 to 8 meq/ml. The variation in the IMC values from 8 to 32 meq/ml for spiramycin and erythromycin indicated that some of these strains were sensitive and other resistant to these two drugs. All strains were resistant to seven antibiotics (streptomycin, bacitracin, polymyxin, chloramphenicol, lincomycine, rifampicine and novobiocine), sometimes at a concentration exceeding 128 meg/ml.

Analysis of membrane proteins of Mycoplasma capricolum strains by SDS-PAGE and immunoblotting.

Sixteen moroccan and five other Mycoplasma (M.) capricolum strains were characterized by SDS-PAGE as well as by the immunobinding assay and immunoblotting, using antisera against M. capricolum California Kid (CK) and M. mycoides YG. There was a strong reaction of all 21 strains with antiserum against M. capricolum CK and of 18 strains with antiserum against M. mycoides YG in the immunobinding assay, confirming the cross-reactivity between these two species observed earlier. A marked heterogeneity among the M. capricolum strains appeared in SDS-PAGE and in immunoblotting, characterized by different protein patterns and different strengths of identical protein bands. All M. capricolum strains investigated revealed, however, at least three strong protein bands with mol. weights of about 30, 42 and 52 KD reacting in immunoblotting with antiserum against M. capricolum CK but not with antiserum against M. mycoides YG. These proteins may represent antigens suitable for the identification and differentiation of M. capricolum strains.

Is short-term odour recognition predictable from odour profile?

Smelling an odour induces a pattern of sensations, images and memories which participate in identification. It was proposed that perceptual memory performances for odours could be inferred from the description of these olfactory representations. The subject was asked to elaborate an odour descriptor profile, and a short-term odour recognition memory task was chosen to test the individual perceptual memory performance. Two pattern-recognition methods based on artificial neural networks and discriminant analysis were carried out and allowed odour profile and perceptual memory performance to be related. Insofar as the subjects gave dichotomic responses in the recognition memory task, each response could be evaluated in terms of correct or incorrect responses. Simulations indicated that the olfactory recognition memory performance can be predicted in man from odour-elicited semantic profiles by using artificial neural networks. It was also shown that all semantic descriptors do not participate in olfactory recognition to the same degree. Low-level information, such as intensity, familiarity and hedonic judgements, did not allow the artificial neural network to predict the olfactory performance. By contrast, high-level information, such as gustatory, olfactory and visual evocations, allowed artificial networks to make such predictions.