Study of Resistance to Orobanche ramosa in Host (Oilseed Rape and Carrot) and Non-host (Maize) Plants

Orobanche ramosa is a parasitic Angiosperm responsible for severe yield losses in several economical crops. It is a serious threat in oilseed rape in France and Morocco and is appearing in carrot crops in Morocco. In this study, several varieties of oilseed rape and carrot were screened in order to identify resistant cultivars and to characterize the resistance mechanisms involved. All the 15 oilseed rape varieties tested were susceptible. In carrot, the varieties 'Colmar à coeur rouge' and 'Nantaise demi-longue' were susceptible, whereas 'Palaiseau' and 'Buror' were resistant. In the susceptible 'Colmar à coeur rouge' carrot no defence reactions were found and the development of the parasite inhibited carrot tap root formation. In the resistant carrot varieties, the parasite germinated, became attached to the host root but became necrotic before emergence. In 'Buror' carrot, formation of a mechanical barrier was associated with the restriction to the cortex of the parasite. In maize cv. 'Vigni', a non-host of O. ramosa, thickening of xylem vessels, cell divisions in the central cylinder and formation of an encapsulation layer were observed in association with restricted development of Orobanche haustoria.     

Study on effects of feeding laying hens on separate mycotoxins (aflatoxins, patulin, or citrinin)-contaminated diets on the egg quality and tissue constituents

Four groups (each of 8 laying hens plus one cock) were offered commercial laying mash contaminated with 100 ppb of aflatoxins, citrinin, patulin or uncontaminated (control) for 6 weeks. The mycotoxin-contaminated diets led to some significant changes in egg characteristics and composition such as ash and calcium contents of the egg shell. The noticeable changes including also the relative weights of adrenal glands. Blood profile reflected too alterations (P greater than 0.05) in urea content and activity of both glutamic oxaloacetic transaminase and alkaline phosphatase as well. The mycotoxins affected significantly moisture and fat contents of the red muscle and protein content, texture and percentage of lean meat in both types of muscles (red and white). Patulin toxicosis was responsible for the strongest alterations in moisture, fat and vitamin A contents of the laying hen's liver and for the lowest calcium content of egg shell besides the shape alteration of the eggs. Laying hens fed on aflatoxin-contaminated diet produced hatched chicks with higher weight (P less than or equal to 0.05) than those from the controls. Citrinin residues were 10 ppb in the fresh muscles and egg yolk and 6 ppb in egg white.     

Suitability of enzymatic hydrolyzates of extracted gluten from fresh pasta by-product used as bread improvers

Gluten extracted from fresh pasta by-products (PG) was enzymatically hydrolyzed by two different commercial proteases (Alcalase 2.4 L and Pancreatin) to different degrees of hydrolysis (DH 2.0, 4.0 and 8.0%). Commercial gluten (CG) was used as reference. The evaluation of functional properties of hydrolyzates from pasta gluten (PGH) and commercial gluten (CGH) showed that Pancreatin hydrolyzates had the highest emulsifying capacities. Regarding the foaming activity, all hydrolyzates performed better than unhydrolyzed gluten. PGH and CGH were added to wheat flour (1%) and their effects on dough rheology were studied. Most hydrolyzates with DH 8% increased dough thermal stability and elasticity during mixing, accelerated the denaturation rate of the protein network, and delayed the gelatinization speed of starch as the temperature increased. Texture profiles and specific volumes of breads from low quality wheat flour with added Pancreatin hydrolyzates (DH 8%) were comparable to those of breads from high quality flour. This showed the potential suitability of PGH and CGH as bread improvers.     

Biochemical and histological alterations of cellular metabolism from jerboa (Jaculus orientalis) by 2,4-dichlorophenoxyacetic acid: Effects on d-3-hydroxybutyrate dehydrogenase

2,4-Dichlorophenoxyacetic acid (2,4D) is one of the widely used herbicide of the phenoxy family with possible startling number of adverse effects on species other than the weeds which is designed to kill. The effects of 2,4D were investigated in jerboa (Jaculus orientalis), a wild animal of subdesert highlands. The jerboas have been daily treated intraperitonally with 2,4D 3 mg/kg body weight for 4 weeks. Plasmatic markers, and antioxidants defences systems were assessed and histological alterations were evaluated. The in vivo and in vitro effects of 2,4D on the mitochondrial d-3-hydroxybutyrate dehydrogenase (BDH) were also determined. Our results showed a strong decrease of triglycerides level and HDL cholesterol and an increase in GOT level and LDL cholesterol. The microscopic evaluation showed that 2,4D induced necrosis of seminiferous tubules cells in testis, hyperplasia of hepatocytes in liver and presence of multinucleated giant cells in brain. The results show also an inhibitory effect on BDH in terms of activity and kinetic parameters. All of these results show that 2,4D induces toxicity which affects energy metabolism, morphological perturbation and oxidative stress.     

Prospects for Reduced Impact Logging in Central African logging concessions

Reduced Impact Logging (RIL) has traditionally been described as a set of forest management practices that reduce logging impacts and improve productivity. In this paper, we review the evolution of the logging sector in the Congo basin since the early 20th century. We argue that logging in the Congo basin has been little influenced by RIL until the recent regional Forestry Law reforms that started in Cameroon in 1994. RIL has not been integrated into the logging sector of the region as an independent body of knowledge, but more as a complement of the new mandatory management plans. In spite of its proven environmental and economic advantages, the role of RIL in improving forest management has been poorly understood, and we identify some causes of this situation. Finally, based on a regional study of 30 concessions, we analyse the frequency of some RIL-related practices and their relation with markets and certification schemes. We conclude that a clear definition of what RIL techniques are embraced by the logging sector is needed if RIL is to fully benefit from the recent development of new market and logging schemes based on certification, improved logging efficiency and a more transparent chain of custody.     

Effect of feedborne fluorine intoxication on broiler chicks' performance, biochemistry, physiology and pathology.

Feeding broiler chicks on graded levels of fluorine (0, 25, 125, 625 and 3125 ppm F) from NaF for 4 weeks (4-7 weeks of age) resulted in various alterations which depended on the level of contamination. The main changes included poor growth and feed conversion, high mortality rate, disorders of bone formation, decreased relative weights of pituitary, adrenal, heart, liver, spleen, lungs, kidneys and gizzard and changes in intestinal dimensions. Also, the biochemical tests revealed other kinds of physiological disfunction mainly in the form of anaemia (low haematocrit, haemoglobin, total protein, albumin and globulin fractions), intoxication (increased methaemoglobin), nephrotic (raised phosphorus and magnesium) and hepatic (elevated lipoproteins and lowering enzymatic activity) disfunctions. The general observations and postmortem examination confirmed also the biochemical findings which revealed the harmful effect of feedborne-fluorine intoxication in broiler chicks.     

Effects of long-term phosphorus fertilizer inputs and seasonal conditions on organic soil phosphorus cycling under grazed pasture

Soil microbes and phosphatase enzymes play a critical role in organic soil phosphorus (P) cycling. However, how long-term P inputs influence microbial P transformations and phosphatase enzyme activity under grazed pastures remains unclear. We collected top-soil (0–75 mm) from a grazed pasture receiving contrasting P inputs (control, 188 kg ha⁻¹ year⁻¹ of single super phosphate [SSP], and 376 kg ha⁻¹ year⁻¹ of SSP) for more than 65 years. Olsen P, microbial biomass P, and acid and alkaline phosphatase enzyme activities were measured regularly over a 2-year period. Pasture dry matter and soil chemical properties were also investigated. Results showed that long-term P inputs significantly increased pasture dry matter, total N, and the concentrations of ${\mathrm{NO}}_3^{–}$–N but significantly decreased soil pH and the concentrations of ${\mathrm{NH}}_4^{+}$–N. Total C was not affected by P fertilization. Although Olsen P significantly increased with increasing long-term P inputs, microbial biomass P was similar under P fertilized treatments. Long-term P inputs decreased acid phosphatase activity but increased alkaline phosphatase activity. Microbial biomass P was similar across seasons in the control but decreased in spring and autumn while increased in summer and winter under P fertilized treatments. Acid and alkaline phosphatase activities were significantly affected by season and followed similar seasonal trends being maximum in summer and minimum in winter regardless of P treatment. Correlation and principal component analysis revealed that acid and alkaline phosphatase activities were significantly positively correlated with soil temperature and significantly negatively correlated with soil moisture. In contrast, Olsen P and microbial biomass P were weakly correlated with environmental conditions. The findings of this study highlight the intertwined relationship between organic P cycling and the availability of C and N in soil systems and the need to integrate both soil moisture and temperature in models predicting organic P mineralization, especially in the context of global climate change.