Levels of some antioxidant molecules and lipid peroxidation during in vivo transformation of the progenetic metacercaria of Clinostomum complanatum to ovigerous adult worms

The levels of oxidative stress markers are an important indicator of the physiological state of the parasite and its host. In the present study levels of lipid peroxidation, glutathione S transferase, glutathione, superoxide dismutase and catalase were determined in the Clinostomum complanatum progenetic metacercaria, obtained from the fish peritoneum (a hypoxic habitat). The in vivo transformed ovigerous adult worms were obtained from the aerobic environment of the buccopharyngeal region of experimentally infected chickens. Levels of antioxidant molecules were also determined in the blood of experimentally infected chickens. An increase in the levels of lipid peroxidation, and a significant decrease in the levels of glutathione S transferase, glutathione, superoxide dismutase and catalase was observed in the infected host as compared to the controls. In the ovigerous worms, the levels of lipid peroxidation, glutathione S transferase, glutathione, superoxide dismutase were found to be significantly less than the levels observed in the progenetic metacercaria. Since the establishment of worm in the buccal cavity of the avian host would lead to its exposure to oxygen and the haematophagous nature of the parasite also exposes it to the free radicals in the host blood, the progenetic metacercaria has evolved to produce excess free radical scavenging molecules reserved to combat the oxidative stress encountered within the microhabitat of the definitive host.     

The complete life cycle in captivity of the spider crab,Maja brachydactyla,Herbst 1788

The present research describes the complete life cycle in captivity, including spawning, larval culture and fattening of juveniles until commercial size. Additionally, size, weight and age at each moulting stage were recorded, as well as zoeas biochemical composition. The most significant results obtained were as follows. Embryonic development lasted for 33 days. Each female had between three and five spawns, separated by 4–5 days each. Larval culture lasted for 20 days at 14–17°C. The zoeas turn to megalopa at ~11 days after hatch/DAH), and from megalopa to juvenile at ~20 DAH. Average survival was ~13%. Juvenile growth rate was higher during the first 8 months (0.22%–0.46% bw/day), and then gradually decreased when changing from live to frozen diets. Survival during the fattening phase was 63%. The final moult occurs at 450 DAH, when males and females have a carapace total length of 12.38 + 1.23 and 13.57 + 1.23 cm, respectively, and 541.56 + 104.26 and 670.68 + 162.6 g in total weight respectively. Biochemical composition of cultured zoeas showed a high amount of phospholipids and long‐chain fatty acids, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and arachidonic acid (ARA). Low survival rates in larval culture and especially after passing to the benthic life style are the main problems regarding spider crab culture, and need to be improved.     

Linking morphological and ecophysiological leaf traits to canopy dieback in Persian oak trees from central Zagros

Intraspecific variability in morphological and ecophysiological leaf traits might be theorized to be present in declining populations,since they seem to be exposed to stress and plasticity could be advantageous.Here we focused on declining Persian oaks(Quercus brantii Lindl.var.persica(Jaub and Spach)Zohary)in the Zagros Mountains of western Iran,representing the most important tree species of this region.We selected trees with contrasting crown dieback,from healthy to severely defoliated,to investigate the relationships between canopy dieback and leaf morphology,water content and pigments.We also measured esterase and peroxidase,as enzymatic antioxidants and indicators of contrasting genotypes.Trees showing moderate to severe defoliation showed higher leaf mass area(LMA),reduced relative water content(RWC),and lower stomatal density(SD).Increasing LMA indicates a more sclerophyllic structure,according to drier conditions.We did not find significant differences in leaf pigments(chlorophyll a and b,and carotenoids)among crown dieback classes,suggesting that Persian oak trees are able to maintain accurate photochemical efficiency,while reduced RWC and SD suggest hydraulic limitations.Our results do not provide a consistent pattern as regards enzymatic antioxidant defense in Persian oak.Morphological leaf traits would be important drivers of future adaptive evolution in Persian oak,leading to smaller and thicker leaves,which have fitness benefits in dry environments.Nonetheless,drought responses may be critically affecting carbon uptake,as photosynthetic compounds are less effectively used in leaves with higher sclerophylly.     

In vitro clonal propagation of mature Tectona grandis through axillary bud proliferation

An in vitro clonal propagation procedure for mature Tectona grandis (teak) trees is described. Multiple shoots were induced from nodal segments through axillary bud proliferation. A shoot multiplication rate of 6.33 was achieved on Murashige and Skoog's (MS) medium supplemented with 10 μM 6-benzyladenine BA and 1 μM 1-naphthalene acetic acid (NAA) during every subculture cycle of 4 weeks. In vitro raised shoots could be successfully rooted (66.66%) on liquid MS medium supplemented with 15 μM NAA, with 1.60 roots per shoot, every 6 weeks of culture. In vitro hardening was carried out in sand soaked with half-strength MS medium (organic free). The plantlets were acclimatized first in a mist chamber and then in polybags in a mixture of soil, sand, and farmyard manure (1 : 1 : 1 v/v) in a shade house.     

The mangrove communities in the Arroyo Seco deltaic fan,Jalisco, Mexico,and their relation with the geomorphic and physical–geographic zonation

This work investigates mangrove tree zonation dynamics in a deltaic fan in the southwestern coast of Mexico. A hypothetical evolution that led to the formation and consolidation of the Arroyo Seco deltaic fan based on the environmental components from the hydrographic basin is proposed. Also, the relief morphogenetic types, along with their sedimentary composition, are derived from geomorphologic and edaphic diagnose methods. Finally, mangrove tree zonation, basal area and height along transects traced parallel to the relief are related to morphogenetic types and to the water table depth during the dry period. There was a clear sedimentological evidence of the accretion process in the deltaic fan. The accretion horizons conditioned the water table, which increased in depth from the margin of the lagoon to the hinterland, thus changing among geoforms. It was much greater at the middle part of the transects, where continental or lagoon water did not infiltrate due to high resistance of clayey soils. The geomorphic zonation of mangrove communities in the Arroyo Seco deltaic fan is: (1) a low fluvial distributary accumulative plain, with coconut palm plantations; (2) a bank fluvial accumulative plain between distributary channels, with coconut palm plantations and patches of low tropical forest; (3) a relatively high swamp accumulative plain, flooded during high water levels, with Avicennia germinans; (4) a low swamp, temporarily flooded accumulative plain, with Rhizophora mangle, Laguncularia racemosa and A. germinans; (5) a very low swamp, permanently flooded accumulative plain, with distributary channels, lateral microbars and tide microdepressions, where Rhizophora and Laguncularia codominate; and (6), a Rhizophora fringe and colonization area along the fan's frontal edge on the same plain. Along this gradient composed of six mangrove communities, basal area and height tended to increase as the water table reached soil level.     

Effect of jasmonic acid on the induction of polyphenoloxidase and peroxidase activities in relation to date palm resistance against Fusarium oxysporum f. sp. albedinis

Bayoud, caused by Fusarium oxysporum f. sp. albedinis (Foa), is the most damaging disease of date palm in Morocco. In the present study we have investigated the effect of jasmonic acid (JA) on two defence-related enzymes, namely peroxidases (POX) and polyphenoloxidases (PPO) in date palm seedlings root. Our data show that exogenous application of JA at a concentration of 50 μM increased the activity of both enzymes. The increase of POX activity in the presence of JA was much more important than that observed following infection with the pathogen. As compared to untreated plants, PPO activity was 2.2 and 1.3 times higher in BSTN and JHL cultivars respectively. In addition, PAGE analysis revealed increased band intensity of the major constitutive isoforms of POX and PPO in both JA-treated and Foa-treated seedlings. Close examination of symptomatic and asymptomatic plants showed that root tissues of symptomatic plants were massively colonized by Foa. Also, disease development in these plants appeared to involve a marked degradation of the host cell walls early during the process of pathogen invasion. In contrast, the presence of Foa in asymptomatic plants induced limited necrotic lesions (hypersensitive-reaction like lesions) that were probably involved in reducing the progression of the pathogen. Together, our findings indicate that JA is capable of enhancing date palm root resistance to infection by Foa via the activation of defence-related enzymes such as PPO and POX.     

Digestive enzyme activity at different developmental stages of blackspot seabream, Pagellus bogaraveo (Brunnich 1768)

Blackspot seabream, Pagellus bogaraveo (Brunnich), has been identified as a potential species to diversify European aquaculture production. Although rearing aspects have been widely investigated, little information exists on the nutritional requirements for this species. The aim of this study was to build up information on the activity of digestive enzymes at certain developmental stages of blackspot seabream in order to understand the nutritional needs of larvae and post larvae. Fish larvae were reared from hatching to 55 days after hatching (dah), and the feeding plan consisted in rotifers (5–35 dah), Artemia naupli (30–35 dah) metanaupli (35–45) and Gemma microdiet (45–55 dah). At 7, 11, 21, 45 and 55 days after hatching (dah), pooled samples of fish larvae were collected for analysis of trypsin, amylase, lipase, alkaline phosphatase and leucine–alanine peptidase activity. Up to 21 dah, the whole larvae body was used for enzymatic analysis, whereas in older larvae only the dissected abdominal cavity was used. Blackspot seabream body dry weight growth was exponential, increasing from 60 μg at 5 dah to 30±9.7 mg at 55 dah. Amylase specific activity decreased significantly during development, exhibiting at 11 dah (0.6 U mg^?1 protein) an average value 2.7 times lower than at 7 dah, and remaining stable between 45 and 55 dah (0.7 U mg protein^?1). Trypsin specific activity remained constant until 21 dah (between 38 and 44 mU mg protein^?1), which could be related to the larvae feeding regime. At later stages of development, lipase‐specific activity exhibited a significant increase (P<0.05), being three times higher at 55 dah (8 U mg protein^?1) than at 45 dah. The total activity of the studied digestive enzymes increased significantly during larval development (until 21 dah), whereas afterwards only lipase and leucine–alanine peptidase increased significantly between 45 and 55 dah. The pattern of digestive enzymes activity was related to organogenesis and the type of food used at different developmental stages.     

Variations of chemical composition of two Algerian essential oils collected for different seasons and assessment of their insecticidal toxicity against three moth pests

Journal of Plant Diseases and Protection - The aims of this work were to point out the seasonal variation in chemical composition and evaluate the insecticidal activities of Mentha spicata and...     

Corn flour-mimosa tannin-based adhesives without formaldehyde for interior particleboard production

A formaldehyde-free adhesive consisting of a corn flour/NaOH adhesive mixture and a mimosa tannin/hexamine intermediate component was developed and evaluated for application to wood panels such as particleboards. The main ingredients of this adhesive include corn flour, NaOH, mimosa tannin and hexamine. This study investigated the physical properties (rheological and thermal analysis) of corn flour/NaOH and mimosa tannin/hexamine adhesives as well as mechanical properties of particleboards produced with these adhesives. Thermomechanical (TMA) experiments indicate the best performance of the adhesives to be around the relative mass proportions of 50:50 between corn flour/NaOH and mimosa tannin/hexamine. Former NMR measurements on corn starch and mimosa tannin proved that the two components behave as a polymer blend rather than co-reacting. The laboratory results show that particleboards bonded with the adhesive at this optimal ratio show good mechanical properties. Moreover, the formaldehyde emission levels obtained from boards bonded with the optimal adhesive were considerably lower to those obtained from boards made with control urea formaldehyde.