Modulation of neuronal activity and hepatic metabolism by ploidy and l‐carnitine supplement in rainbow trout (Oncorhynchus mykiss)

l ‐carnitine, a multiphysiological, bioactive and pollution‐free additive, is known to act as a growth‐enhancer and appears to act as an antioxidant compound. However, high dosages may cause detrimental physiological effects to fish. Considering such, a feeding trial was carried out to evaluate the effects of dietary l ‐carnitine content on neuronal activity (acetylcholinesterasic activity), hepatic metabolism (catalase activity) and liver histological markers in both diploid and triploid trout (Oncorhynchus mykiss) juveniles. Fish were hand‐fed for 56 days on three nutritionally identical diets, varying in l ‐carnitine content; unsupplemented diet (15 mg kg^?1) and supplemented (200 or 530 mg kg^?1) diets. Moderate to severe glycogen/lipid depletion was the major liver histopathological disorder observed in all dietary groups. This cause–effect relationship appeared to be dose and time‐dependent, suggesting an important role of l ‐carnitine in the liver metabolism. Moreover, the hepatocite size and nuclear diameter appeared to be larger in l ‐carnitine supplemented groups than in control group. l ‐carnitine caused significant induction of catalase activity and inhibition of AChE. Diploid and triploid trouts showed marked differences in enzymatic activities, reflected by consistently higher values of AChE activities for triploid animals.     

Antioxidant activity of a catechol derived from abietic acid

The demand for novel effective antioxidant-based drugs has led to the synthesis and evaluation of the antioxidant potential in several molecules derived from natural compounds. In this work the in vitro antioxidant activity of an abietic acid-derived catechol (methyl 11,12-dihydroxyabietate-8,11,13-trien-18-oate, MDTO) was evaluated. This substance, possessing important biological properties, is similar to carnosic acid, a natural antioxidant from rosemary or sage leaves. Aiming to understand the antioxidant activity of MDTO, the energetics of its O-H bond, using time-resolved photoacoustic calorimetry (TR-PAC), was investigated. On energetic grounds it is predicted that MDTO is a good free radical scavenger, although its activity is lower than that of quercetin, a very effective antioxidant, which was used for comparison. In agreement with these predictions, the DPPH(*) and ABTS(*+) radical scavenging activities are lower than those of quercetin. In addition, MDTO also reacts with HOCl, a powerful proinflammatory oxidant produced by activated neutrophils, and protects liposomes against iron-ascorbate-induced oxidation. The discussion of these results foresees potential applications of MDTO as an antioxidant.     

Tolerance of potentially diazotrophic bacteria to adverse environmental conditions and plant growth-promotion in sugarcane

Sugarcane is one of the crops responsible for the high consumption of fertilizers in Brazil. To minimize this demand a sustainable alternative is to increase the studies to evaluate the beneficial effects of the relationship between plants/microorganisms, mainly plant growth-promoting bacteria. The objectives of this study were: a) to evaluate potentially diazotrophic bacteria isolates from sugarcane in adverse environmental conditions; b) inoculate these bacteria in sugarcane to evaluate their ability in plant growth-promotion. The study was carried in the Northeast of Brazil. Bacterial genera Burkholderia sp., Pantoea sp., Stenotrophomonas sp. and Enterobacter sp. were evaluated in different culture medium and later the bacterial isolates were inoculated in sugarcane evaluating the plant growth-promotion. Stenotrophomonas sp. and Pantoea sp. were tolerant to salinity and to different sources of carbon in acid medium and too tolerated high concentrations of pesticides and produced quorum sensing molecules (QS), but did not increase the dry matter production of sugarcane. Burkholderia sp. and Enterobacter sp. were more sensitive to salinity and pest control, but were more effective in plant growth-promotion. The tolerance of the bacteria to the adverse environmental conditions interfered negatively in the ability to plant growth-promotion.     

Screening of lactic acid bacteria potentially useful for sorghum fermentation

A screening of commercial lactic acid bacteria potentially useful in the improvement of sorghum nutritional quality was done. The aim of this study was to test starter cultures to meet the prerequisites for the establishment of small-scale industrial production of sorghum fermented foods in Africa.     

Comparison of the effects induced by different processing methods on sorghum proteins

The effects induced by cooking, dry heating, popping, fermentation and germination on sorghum proteins were studied. Changes promoted by these processing methods were compared via sodium dodecyl sulfate polycrylamide gel electrophoresis (SDS-PAGE), in vitro protein digestibility (IVPD) assay and Fourier Transform Infrared (FT-IR).     

Relationship between tipburn and leaf mineral composition in strawberry

Malformation of emerging leaves with distortion of leaf tips, a condition known as tipburn, is frequently observed in strawberry. Calcium (Ca) deficiency has been considered the main cause of tipburn. The aim of the present study was to analyse the relationship between leaf mineral composition and the incidence of tipburn in three short-day strawberry (Fragaria x ananassa Duch.) cultivars (‘Ventana’, ‘Camarosa’ and ‘Candonga’) submitted to different concentrations of Ca. The studies were conducted in a hydroponic system in a greenhouse. Calcium was added as Ca(NO₃)₂ at 2 mM, 3 mM, 4 mM and 5 mM. A completely randomized block design (4 Ca concentrations × 3 cultivars) with three replications was used. Each replicate consisted of 12 plants grown in a polyethylene bag (100 cm × 18 cm × 3 cm) filled with coconut peat. Crown diameter and tipburn incidence were evaluated throughout the experimental period, and at the end of the experiment leaf mineral composition was assessed. In general, plants with larger crown diameters had a greater incidence of tipburn. The ‘Candonga’ cultivar had the smallest incidence of tipburn, while the ‘Camarosa’ and ‘Ventana’ cultivars were more susceptible. There was no correlation between level of Ca applied and incidence of tipburn. The incidence of tipburn was associated with foliar K:Ca and K:Mg ratios. Ratios above 3.40 for K:Mg and 1.77 for K:Ca represented a risk of more than 50% of tipburn incidence, when overall means for all cultivars and levels of Ca were used.     

Continental drainage in north america during the phanerozoic from Nd isotopes

Neodymium (Nd) isotopic data show consistent patterns in the sources of sedimentary rocks in North America at a continental scale. Between 600 and 450 million years ago (Ma), ancient continental shield sources dominated. Around 450 Ma, detritus from the Caledonian-Appalachian mountains overwhelmed sediment from all older sources, and is documented over large areas of the southern, western, and northern margins of North America. This material continued to dominate the sediment supply until about 150 Ma, probably due to cannibalistic recycling of sedimentary rocks formed earlier. Around 150 Ma, the rising western Cordillera delivered new and different detritus to the sedimentary system.     

Cambrian burgess shale animals replicated in clay minerals

Although the evolutionary importance of the Burgess Shale is universally acknowledged, there is disagreement on the mode of preservation of the fossils after burial. Elemental mapping demonstrates that the relative abundance of elements varies between different anatomical features of the specimens. These differences reflect the compositions of the minerals that replicated the decaying organism, which were controlled by contrasts in tissue chemistry. Delicate morphological details are replicated in the elemental maps, showing that authigenic mineralization was fundamental to preserving these fossils, even though some organic remains are also present.     

Age, growth and reproductive biology of the European conger eel (Conger conger) from the Atlantic Iberian waters

The European conger eel, Conger conger, is a fish widely distributed in the north-eastern Atlantic, being an important commercial and recreational fish species. A total of 85 juvenile congers eels were used in this study. Seventy-three congers were captured mainly by hook and pots in inshore waters (10–15 m depth) of the Iberian Peninsula (North Portugal and Vigo), monthly from March 1998 to March 2000. Another twelve specimens have been captured during a research cruise (R.V. “Capricórnio”) in summer 1999 by trawl at depths about 400 m in south Portugal. The length and weight of the congers eels ranged from 38 to 173 cm and 125 to 14,553 g, respectively. The observation of burnt otoliths under UV light proved to be a useful method for ageing conger eels. Marginal increment analysis was used to validate the annual pattern in the deposition of bright zones in the otoliths. Age for the congers ranged from 2 to 12 years. The VBF population growth curve estimates from the otoliths of the females gave results of L_∞ = 265 cm, k = 0.07 and t₀ = −1.20. Sex determination and gonadal development were obtained from histological analysis. All the specimens collected in the coastal shallow waters were females, either immature or in a developing stage. The ovaries contained oocytes in two main stages of development: a pre-vitellogenic stage and an early vitellogenic stage. The few males (n = 4) observed have been captured in the trawl fishery at deeper waters. The males possessed small cells spermatogonias and spermatocytes clustered in crypts in the testis scattered in a matrix of adipose tissue. The sexual steroids, 17β-oestradiol and testosterone, were measured in blood plasma samples by solid-phase radioimmunoassay. Both sexual steroids presented a high correlation with the sexual development stage in terms of maximum oocyte diameter and gonadosomatic index. This work presents for the first time, data on age, reproductive biology and endocrinology of conger eels captured in the west coast of the Iberian Peninsula.