Biodegradation kinetics of dicofol by selected microorganisms

The capacity of some plant growth promoters (seven species of bacteria namely, Azospirillium barasilense, Azotobacter chroococcum, Klebsilense pneumoneae, Pseudomonas cepacia, Bacillus subtilis, Pseudomonas fluorescens and Bacillus polymyxa) and some control agents for plant pathogens (two species of fungi namely, Trichoderma viride and Trichoderma harzianum) to degrade dicofol pesticide (DCF) in liquid culture media was investigated. The recovered amount of DCF was extracted based on the solid phase extraction (SPE) with methylene chloride and then analyzed by HPLC. Contrary to published reports, no intermediate or final degradation metabolites of DCF could be observed. About 26-33% of DCF degradation was observed after 3 days of incubation with the tested bacteria which increased to 61-80%, 74-85%, 77-87% and 75-94% after 7, 14, 21 and 28 days of incubation, respectively. On the other hand, the tested fungi removed roughly 35% of available DCF within the first three days of incubation which increased to 84-87%, 89-95%, 91-95% and 92-96% after 7, 14, 21 and 28 days of incubation, respectively. A biphasic model was assumed to explore the disappearance of DCF from media enriched with either bacteria or fungi, where the rate of disappearance in the first phase was faster than the second. This is clearly reflected in the half-life (t_1/2) for the first and second phases, where the t_1/2 values of DCF ranged from 2.82-4.42 to 19.32-29.73 days, respectively. The results have implications for the development of a bioremediation strategy.     

Differentially-regulated defence genes in Malus domestica during phytoplasma infection and recovery

To improve knowledge about plant/phytoplasma interactions and, in particular, about the ‘recovery’ phenomenon in previously-infected plants, we investigated and compared expression levels of several defence-related genes (four pathogenesis-related proteins and three jasmonate-pathway marker enzymes) in apple plants showing different states of health: vigorous (healthy), phytoplasma-infected, and recovered. Real Time-PCR analyses demonstrated that genes are differentially expressed in apple leaf tissue according to the plants’ state of health. Malus domestica Pathogenesis-Related protein (MdPR) 1, MdPR 2 and MdPR 5 were significantly induced in leaves of diseased and symptomatic plants compared to leaves of those plants that were healthy or recovered. On the other hand, levels of all the jasmonate (JA)-pathway marker genes that we selected for this study, were up-regulated in the leaves of recovered plants compared to the diseased ones. In conclusion, our study demonstrated that two different sets of defence genes are involved in the interactions between apple plants and ‘Candidatus Phytoplasma mali’ (‘Ca. P. mali’) and that these genes are differentially expressed during phytoplasma infection or recovery.     

Study on prevalence and bacterial etiology of mastitis,and effects of subclinical mastitis and stage of lactation on SCC in dairy goats in Egypt

Tropical Animal Health and Production - In Egypt, inadequate information on prevalence and epidemiology of caprine mastitis is available. This study was designed to investigate prevalence and...     

Comparative Analysis of Genetic Diversity in Two Tunisian Collections of Fig Cultivars Based on Random Amplified Polymorphic DNA and Inter Simple Sequence Repeats Fingerprints

This study characterized the genetic diversity of 18 Tunisian fig cultivars using random amplified polymorphic DNA (RAPD) and inter simple sequence repeats (ISSR). Both random and ISSR primers tested generated a total of 116 RAPD and 47 ISSR markers. Considerable genetic variation was observed among fig cultivars sampled from two regional Tunisian collections with an average diversity of 4.57. RAPD and ISSR banding patterns and genetic distances values reflected the high level of diversity among the collections and lower variability between the two collections. The correlation between the RAPD and ISSR similarity matrices computed for the 153 pairwise comparisons among the 18 varieties was lower and significant. An analysis of molecular variance showed that 92% of the total genetic diversity resided within collections, whereas only 8% between collections. The results indicated that in the local fig germ plasm the information provided by RAPD and ISSR is not analogous, most likely as a consequence of the fact that the two classes of markers explore, at least in part, different portions of the genome.     

Accelerated hydrolysis method to estimate the amino acid content of wheat (Triticum durum Desf.) flour using microwave irradiation

The technique of microwave-assisted acid hydrolysis was applied to wholegrain wheat (Triticum durum Desf. cv. Balcali 2000) flour in order to speed the preparation of samples for analysis. The resultant hydrolysates were chromatographed and quantified in an automated amino acid analyzer. The effect of different hydrolysis temperatures, times and sample weights was examined using flour dispersed in 6 N HCl. Within the range of values tested, the highest amino acid recoveries were generally obtained by setting the hydrolysis parameters to 150 °C, 3 h and 200 mg sample weight. These conditions struck an optimal balance between liberating amino acid residues from the wheat matrix and limiting their subsequent degradation or transformation. Compared to the traditional 24 h reflux method, the hydrolysates were prepared in dramatically less time, yet afforded comparable ninhydrin color yields. Under optimal hydrolysis conditions, the total amino acid recovery corresponded to at least 85.1% of the total protein content, indicating the efficient extraction of amino acids from the flour matrix. The findings suggest that this microwave-assisted method can be used to rapidly profile the amino acids of numerous wheat grain samples, and can be extended to the grain analysis of other cereal crops.     

Response of the tomato miner Tuta absoluta (Lepidoptera: Gelechiidae) to thirteen insecticides in semi‐natural conditions in Tunisia

Experiments on larvicide and ovicide activity of 13 insecticides in semi‐natural conditions showed a medium to low efficacy of bio‐insecticides on all instars of Tuta absoluta (Meyrick) except for Bacillus thuringiensis Berliner var. kurstaki which was distinguished by an average mortality of 72.5%. Spinosad and Spinetoram based insecticides showed high efficiency in controlling all instars of larvae with respectively an average mortality of 66.5% and 85.6%. However, this study revealed a unique ovicide effect of azadirachtin‐neem oil based insecticide with 43.8% egg mortality.     

Evaluation of two methods for the protection of tomato crops against the tomato leafminer Tuta absoluta (Meyrick) under greenhouses in Tunisia

The evaluation of two methods of plant protection in tomato crops cultivated in greenhouses against Tuta absoluta (Meyrick) in the region of Teboulba in Tunisia was performed. This study evaluated the use of insect‐proof screens alone or in combination with one sex pheromone water trap compared to a control greenhouse not equipped with either. The study confirms that the use of one sex pheromone water trap combined with insect‐proof covering of doors and aeration openings is sufficient to guarantee good crop protection. This combined control system allowed a low density of the pest (less than 2 individuals per leaf) to be maintained and a mean number of mines below 1 mine per leaf.     

<Emphasis Type="Italic">Manihot fortalezensis</Emphasis> Nassar,Ribeiro, Bomfim et Gomes a new species of <Emphasis Type="Italic">Manihot</Emphasis> from Ceará, Brazil

A new species of Manihot has been collected from Fortaleza, Ceará state, Brazil. It was grown at the living collection in the experimental station, University of Brasilia since 1980 and left for natural reproduction. It bred true during all these years giving rise to identical typical plants of the ancestor one. The closest species to it is M. glaziovii. Apparently this new species was formed by sporadic hybridization between M. glaziovii and cassava itself in its natural habitat, Ceará. It possesses morphological marker gene of the latter one which is ribbed fruit that is found only in cassava. Interspecific hybrids produced experimentally between M. glaziovii and cassava showed similar morphological markers. Exam of its ovules revealed formation of multiple embryos, an indicator of apomixis. Grafting it with common cassava was compatible, giving increased root size up to seven times.     

Recent molecular and breeding strategies in lettuce (Lactuca spp.)

Genetic Resources and Crop Evolution - Lettuce (Lactuca spp.) is an annual and self-pollinating crop that belongs to the Asteraceae (Compositae) family. It is one of the most globally essential...