Impact of soil water content on maize responses to the plant growth-promoting rhizobacterium Azospirillum lipoferum CRT1

Members of the bacterial genus Azospirillum are root-associated bacteria that increase yield in cereals by promoting growth and alleviating drought stress. How plants integrate the many bacterium-derived growth-promoting stimuli with other environmental factors to generate a coordinated response remains unresolved. Using a commercial Azospirillum strain, A. lipoferum CRT1 and two host maize cultivars, it was observed that bacterization reduced the drought-induced increase in lateral root growth and enhanced the flood-induced increase in lateral root growth in the more drought- and flood-sensitive cultivar. In the other one, A. lipoferum CRT1 only elicited a moderate root growth response under low soil water potential. The photosynthetic potential and activity were increased in the earlier cultivar and decreased in the later one, irrespective of the soil water content. No impact of the bacterium was seen on the growth of the leaves of both cultivars under both stresses until the third leaf stage, therefore suggesting that it is a consequence of multiple primary adaptations to biotic and abiotic stresses. It is suggested that host–bacteria recognition leads to a stress-specific modulation of the root response and a differential stress-independent effect on photosynthesis. This is the first report of the impact of Azospirillum under flood conditions.     

Sentinel-2 images reveal functional biophysical heterogeneities in crop mosaics

Landscape Ecology - Identifying landscape structure and understanding its functions are crucial for biological control. However, the relationship between the crop mosaic phenological heterogeneity...     

Influence of dietary fat and vitamin E supplementation on free radical production and on lipid and protein oxidation in turkey muscle extracts

The objectives of this study were to investigate the effects of dietary fat (6% soy oil or rapeseed oil or tallow) and alpha-tocopheryl acetate supplementation at two levels (30 or 200 ppm) on radical production, measured by ESR spectroscopy, and on lipid and protein oxidation in turkey muscle extracts oxidized by an enzymic system (NADPH, ADP, FeSO(4)/cytochrome P450 reductase). Two muscles were tested: pectoralis major (glycolytic) and sartorius (oxidative) muscles. Radical production measured by ESR was higher in pectoralis major muscle than in sartorius muscle, whereas lipid and protein oxidation was more important in sartorius muscle, showing the importance of the pro-/antioxidant ratio in oxidative processes in muscular cells and of the measurement methodology to appreciate the free radical production. Dietary fat had no effect on the level of ESR signals, whereas feeding of animals with soy oil induced higher oxidation of lipids. Protein oxidation was less sensitive to the nature of the dietary fat than lipid oxidation. Vitamin E supplementation significantly decreased radical production, as measured by ESR spectroscopy. Vitamin E also decreased lipid and protein oxidation, but the effect of vitamin E on protein oxidation was less pronounced than on lipid oxidation.     

Derivatives of pesticides with an α-amino acid function: Synthesis and effect on threonine uptake

The synthesis of several derivatives of a pesticide and an α-amino acid are described. The process involves three steps, the last one (deprotection of the α-amino acid group) being the most critical. The resulting products preserved their α-amino acid group and were globally neutral. They were tested for their effect on the transport of a neutral amino acid, threonine, and two sugars, sucrose and glucose. Two derivatives markedly and specifically inhibited threonine uptake by leaf tissues of Vicia faba L. and phloem loading. Preliminary experiments suggested that the lysine-2,4-D derivative is a competitive inhibitor of threonine uptake. The apparent K_i (0.5 mM) was much lower than the apparent K_m (3 mm) of the natural substrate.     

Different ethylene production in vitro by several species and formae speciales of Fusarium

The ethylene production of severalFusarium species and formae speciales in vitro was measured under comparable conditions. All of them produced ethylene.Fusarium oxysporum Schlecht. ex Fr. f.tulipae Apt. produced much more than the other 18 strains investigated.Samenvatting Aangezien er aanwijzingen zijn dat ethyleen een rol speelt bij de aantasting van de tulpebol doorFusarium, werd de ethyleenproduktie van diverse soorten en formae speciales vanFusarium onder standaardvoorwaarden in vitro vergeleken. Alle onderzochteFusarium spp. en vormen vanFusarium produceerden ethyleen.Fusarium oxysporum Schlecht. ex Fr. f.tulipae Apt. bleek in vergelijking met 18 andere getoetste soorten en formae speciales enige duizenden malen meer ethyleen te produceren.     

Evaluation of the safety of ivermectin-praziquantel administered orally to pregnant mares

OBJECTIVE: To evaluate the safety of an orally administered ivermectin and praziquantel paste with regard to variables associated with clinical findings, parturition, lactation, maternal care, and neonate viability in pregnant mares. ANIMALS: 40 pregnant mares. PROCEDURE: Mares were randomly allocated into treatment (n = 20) and control (20) groups and administered a placebo or 3 times the therapeutic dosage of ivermectin (0.6 mg/kg) and praziquantel (4.5 mg/kg) at 14-day intervals until parturition. Physical examinations were performed on mares and their foals after parturition (on postpartum days 30, 60, and 90) to identify any drug-related effects. As an aid in assessing general health, hematologic and serum biochemical analyses were performed monthly on the mares. RESULTS: In blood constituents, minor alterations that were not biologically important were observed. Reproductive performance was not affected by the unusual treatment duration or high dosage, although the drugs were administered during a crucial period of equine embryonic development (30 to 60 days). Neither adverse effects on mares nor abortions occurred. Follow-up evaluations of the foals for a 3-month period did not detect any abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of the ivermectin-praziquantel paste appears to be safe in pregnant mares and their foals.     

Isolation and characterisation of local strains of Chlamydophila abortus (Chlamydia psittaci serotype 1) from Tunisia

Chlamydiosis is one of the major diseases that can lead to abortion in ewes. Since 1997, in 5 regions of Tunisia, Chlamydia-related abortions have been reported in 15 sheep and goat flocks. One hundred and sixty-six sera and 50 vaginal swab samples were collected from adult ewes. Chlamydial antigens were detected in 29 (58%) of the vaginal swabs using Enzyme Linked Immunosorbent Assay (ELISA) while 9 (18%) were positive by cell culture. Five strains were recovered from 4 different sheep flocks. Monoclonal antibody profiles and restriction fragment length polymorphism (RFLP) analysis of the 16S-23S rRNA spacer region showed that these isolates were C. abortus. Using amplified fragment length polymorphism (AFLP), these Tunisian strains were shown to exhibit the same pattern as strains isolated in France.