Growth Curves for Macrobrachium rosenbergii in Semi-Intensive Culture in Brazil

Abstract.— Four 0.02-ha earthen ponds at the UNESP Aquaculture Center, Jaboticabal, São Paulo, Brazil, were stocked with newly metamorphosed Macrobrachium rosenbergii post-larvae at 1.5 animals/m². After 8 mo, prawn density at harvest ranged from 0.3/m² to 0.8/m². Growth curves were determined for each population using von Bertalanffy growth functions. Asymptotic maximum length and asymptotic maximum weight increased as final population size decreased indicating that a strong density effect on prawn growth occurs in semi-intensive culture, even when populational density varies within a small range of less than 1 animal/m².     

ARBUSCULAR MYCORRHIZAL FUNGI IN REVEGETATED MINED DUNES

This study aimed to thoroughly investigate communities of arbuscular mycorrhizal fungi (AMF) in six coastal, mined, reconstituted and revegetated dune areas in Northeast Brazil. AMF spore density and species richness as well as the numbers of infective AMF propagules and glomalin‐related soil protein (GRSP) were analyzed. Four areas had been restored for 16, 12, 8 and 4 years, and after being mined, reconstituted and re‐vegetated, the fifth was mined and reconstituted but not yet re‐vegetated, and the sixth had a native and undisturbed coastal forest vegetation. The soil samples were sampled in the dry and wet seasons of 2005. The number of infective propagules was significantly higher in the dry than in wet season, except in the un‐vegetated dune area, which had less than 0·2 propagules cm⁻³ soil. AMF spore density and especially GRSP contents changed little between the seasons. GRSP contents were positively correlated to Al and Fe soil levels and were highest in the restinga forest. In total, 29 AMF species were identified, and glomoid and gigasporoid species predominated in all areas. AMF species richness and viable propagules of AMF were lowest in the un‐vegetated dune area. Remarkably, higher species richness (28) was found in the re‐vegetated areas, compared with the forest area that had only 10 species. The numbers of infective propagules tended to be also lower in the forest than in the re‐vegetated sites. In conclusion, re‐vegetation appears to favour the AMF communities in terms of infective propagule numbers and AMF species richness. Copyright © 2011 John Wiley & Sons, Ltd.     

Potential for carbon sequestration after biochar-P fertilizer application: A biological and chemical assessment

Innovation is required on many fronts in agriculture, not only to improve nutrient use efficiency but also to mitigate the effects of climate change. Our previous studies presented the high agronomic efficiency of an experimental phosphate fertilizer using a biochar-matrix, called ‘BioFert’. However, the efficiency of BioFert for soil carbon sequestration goals has not yet been evaluated. We incubated BioFert and initial raw sugarcane-biochar over 56 days in two soils (i.e., Ferralsol and Alisol) and measured the total CO₂ and δ¹³C-CO₂ to quantify the contribution of native soil organic matter, sugarcane-biochar, or BioFert to carbon mineralization. There was no significant difference in cumulative CO₂ release between BioFert and the control (without carbon addition), and BioFert was less mineralized than carbon from sugarcane-biochar regardless of soil type. In addition, accelerated aging by thermal oxidation of these carbon sources revealed that more than 80% of BioFert-carbon was prevented from accelerated mineralization, while sugarcane-biochar achieved ~80% of carbon mineralization. The residual solids after oxidation were analysed by X-ray photoelectron spectroscopy and indicated aliphatic/aromatic and carboxylic chemical bonds on the BioFert surface, which might offer new cation exchange sites over time. We conclude that BioFert is not only a phosphate fertilizer with high phosphorus use efficiency but also a stable source of carbon for soil carbon sequestration purposes.     

Use of recombinant cyprosin in the manufacture of ewe's milk cheese

A recombinant cyprosin from the cardoon (Cynara cardunculus L.) was assayed and compared with calf rennet in batches of ewes' milk cheese by determining different chemical, biochemical, and microbiological parameters over 4 months of ripening. There were no differences between the two types of coagulants in most chemical parameters, a(w), and pH. Proteolysis was more marked and rapid in cheese containing recombinant cyprosin as coagulant, the soluble nitrogen content of which was significantly higher (p < 0.01) than that of the cheese obtained with animal rennet; at the end of ripening the nonprotein nitrogen of cheese produced with recombinant cyprosin was slightly higher (p > 0.05) as compared with that in cheeses obtained with animal rennet. Microbial counts in the milk used for making cheese were high in most of the groups analyzed. Despite slight differences in counts, the main microbial groups analyzed were similar in cheese produced with both types of coagulants throughout ripening.     

A recombinant form of chagasin from Trypanosoma cruzi: inhibitory activity on insect cysteine proteinases

BACKGROUND: The activity of the major digestive cysteine proteinase detected in the intestinal tract of larvae of the bean weevil, Acanthoscelides obtectus (Say), was efficiently inhibited by the well-characterized cysteine proteinase synthetic inhibitor E-64 and also by a recombinant form of chagasin (r-chagasin), a tight-binding cysteine proteinase inhibitor protein from Trypanosoma cruzi. RESULTS: Incorporation of r-chagasin into an artificial diet system at 0.1 g kg(-1) retarded growth rate, decreased larval survival and led to complete mortality of A. obtectus at the end of the trial. The observed differences in growth rates occurred particularly in the first and second development stages. Artificial seeds containing high levels of r-chagasin (0.5-30 g kg(-1)) completely inhibited larval penetration. CONCLUSION: Together, the results reported in this paper support the hypothesis that the inhibitory activity of r-chagasin towards the major insect gut cysteine proteinase in vitro and in vivo is an accurate prediction of its insecticidal effects. The selectivity of this inhibitor against insect digestive proteinases supports the key role in parasite virulence by affecting the endogenous proteinase activity in its natural host.