Effect of N source during soybean pod filling on nitrogen and sulfur assimilation and remobilization

During pod filling, a grain legume remobilizes vegetative nitrogen and sulfur to its developing fruit. This study was conducted to determine whether different nitrogen sources affected N and S assimilation and remobilization during pod filling. Well-nodulated plants fed 1.0 mM KNO₃, 0.5 mM urea, or 2.5 mM urea assimilated 0%, 37%, or 114% more N, respectively, and 25%, 46%, or 56% more S, respectively, than did the average non-nodulated control plant fed 5.0 mM KNO₃. Thus, N source during pod filling greatly affected both N and S assimilation. Depending upon N source, plant N concentration during pod filling decreased from 2.96% to between 1.36% and 1.82%. Non-nodulated control plants fed 5.0 mM KNO₃ had the highest residual N at harvest. During the same treatments, plant S concentration decreased from 0.246% to a relatively uniform 0.215%. Thus, during pod filling, vegetative N was seemingly remobilized more efficiently (38–54%) than was S (13%). N source also affected seed yield and seed quality. Non-nodulated control plants fed 5.0 mM KNO₃ produced the lowest yield (21.1 g seeds plant^-1), whereas well nodulated plants fed 1.0 mM KNO₃, 0.5 mM urea, or 2.5 mM urea produced yields of 26.2 g, 31.8 g, and 36.7 g seeds plant^-1, respectively. Non-nodulated plants fed 2.5 mM urea yielded 28.6 g of seeds plant^-1. Seed N concentrations of non-nodulated plants and nodulated plants fed 2.5 mM urea were high, 6.30% and 6.11% N, respectively, whereas their seed S concentrations were low, 0.348% and 0.330% S, respectively. N sources that produced both a relatively high seed yield and seed N concentration (i.e., a relatively high total seed N plant^-1) produced a proportionately smaller increase in total seed sulfur. Consequently, seed quality, as judged solely by seed S concentration, was lowered.     

Phylogeographic Patterns and Evolution of the Mitochondrial DNA Control Region in Two Neotropical Cats (Mammalia, Felidae)

The ocelot (Leopardus pardalis) and margay (L. wiedii) are sister-species of Neotropical cats which evolved from a lineage that migrated into South America during the formation of the Panamanian land bridge 3–5 million years ago. Patterns of population genetic divergence of each species were studied by phylogenetic analyses of mitochondrial DNA (mtDNA) control region sequences in individuals sampled across the distribution of these taxa. Abundant genetic diversity and remarkably concordant phylogeographic partitions for both species were observed, identifying parallel geographic regions which likely reflect historical faunal barriers. Inferred aspects of phylogeography, population genetic structure, and demographic history were used to formulate conservation recommendations for these species. In addition, observed patterns of sequence variation provided insight into the molecular evolution of the mtDNA control region in closely related felids. Received: 26 January 1998 / Accepted: 14 May 1998     

Safety and Immunogenicity of the Malaria Vaccine Candidate MSP3 Long Synthetic Peptide in 12–24 Months-Old Burkinabe Children

Background

A Phase Ia trial in European volunteers of the candidate vaccine merozoite surface protein 3 (MSP3), a Plasmodium falciparum blood stage membrane, showed that it induces biologically active antibodies able to achieve parasite killing in vitro, while a phase Ib trial in semi-immune adult volunteers in Burkina Faso confirmed that the vaccine was safe.The aim of this study was to assess the safety and immunogenicity of this vaccine candidate in children aged 12–24 months living in malaria endemic area of Burkina Faso.

Methods

The study was a double-blind, randomized, controlled, dose escalation phase Ib trial, designed to assess the safety, reactogenicity and immunogenicity of three doses of either 15 or 30 µg of MSP3-LSP adsorbed on aluminum hydroxide in 45 children 12 to 24 months of age randomized into three equal groups. Each group received 3 vaccine doses (on days 0, 28 and 56) of either 15 µg of MSP3-LSP, 30 µg of MSP3-LSP or of the Engerix B hepatitis B vaccine. Children were visited at home daily for the 6 days following each vaccination to solicit symptoms which might be related to vaccination. Serious adverse events occurring during the study period (1 year) were recorded. Antibody responses to MSP3-LSP were measured on days 0, 28, 56 and 84.

Results

All 45 enrolled children received three MSP3 vaccine doses. No serious adverse events were reported. Most of the adverse events reported were mild to moderate in severity. The only reported local symptoms with grade 3 severity were swelling and induration, with an apparently dose related response. All grade 3 adverse events resolved without any sequelae. Both MSP3 doses regimens were able to elicit high levels of anti-MSP3 specific IgG1 and IgG3 antibodies in the volunteers with very little or no increase in IgG2, IgG4 and IgM classes: i.e. vaccination induced predominantly the isotypes involved in the monocyte-dependent mechanism of P. falciparum parasite-killing.

Conclusion

Our results support the promise of MSP3-LSP as a malaria vaccine candidate, both in terms of tolerability and of immunogenicity. Further assessment of the efficacy of this vaccine is recommended.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00452088","term_id":"NCT00452088"}}NCT00452088     

Regulation of low-molecular weight organic acid production in fungi

Organic acids produced by fungi have been proposed to have many roles in wood-decay processes, lignocellulose degradation or plant pathogenesis involving saprotrophic or pathogenic fungi, as well as in nutrient acquisition and metal detoxification involving mycorrhizal or rhizosphere-inhabiting fungi. In comparison with other fungi, a considerable body of work has been devoted to the comprehension of biosynthesis pathways in fungi involved in industrial production of organic acids, and also in those involved in wood-decay processes and pathogenicity. In this review we therefore focus on information available from these different types of low-molecular weight organic acid (LMWOA) producing fungi in order to better understand the environmental cues involved in regulating production of LMWOAs.     

Sulfonamides with the N-alkyl-N′-dialkylguanidine moiety as 5-HT7 receptor ligands

A series of arylsulfonamides containing guanidine incorporated in the structure of secondary amines (piperidine, piperazine) was synthesized on SynPhase Lanterns and evaluated for 5-HT_1A, 5-HT_2A, and 5-HT₇ receptors. The results demonstrated that N-alkyl-N′-dialkylguanidines displayed good 5-HT₇/5-HT_1A selectivity and may be regarded as promising structural core for development of 5-HT₇ ligands.     

Morphometrics Parallel Genetics in a Newly Discovered and Endangered Taxon of Galápagos Tortoise

Galápagos tortoises represent the only surviving lineage of giant tortoises that exhibit two different types of shell morphology. The taxonomy of Galápagos tortoises was initially based mainly on diagnostic morphological characters of the shell, but has been clarified by molecular studies indicating that most islands harbor monophyletic lineages, with the exception of Isabela and Santa Cruz. On Santa Cruz there is strong genetic differentiation between the two tortoise populations (Cerro Fatal and La Reserva) exhibiting domed shell morphology. Here we integrate nuclear microsatellite and mitochondrial data with statistical analyses of shell shape morphology to evaluate whether the genetic distinction and variability of the two domed tortoise populations is paralleled by differences in shell shape. Based on our results, morphometric analyses support the genetic distinction of the two populations and also reveal that the level of genetic variation is associated with morphological shell shape variation in both populations. The Cerro Fatal population possesses lower levels of morphological and genetic variation compared to the La Reserva population. Because the turtle shell is a complex heritable trait, our results suggest that, for the Cerro Fatal population, non-neutral loci have probably experienced a parallel decrease in variability as that observed for the genetic data.     

An integrated comparative approach to mangrove vegetation mapping using advanced remote sensing and GIS technologies: preliminary results

This study aims to develop an integrated methodology applying Remote Sensing and Geographic Information Systems (GIS) techniques for the assessment of the ecological status of mangrove forests. The study area is located at Phangnga Bay, Thailand. Various commonly available remote sensing data are evaluated for mangrove vegetation mapping. The satellite sensors used are covering the visible and infra-red (VIR) spectrum up to the microwave region of the electromagnetic spectrum. This study provides recommendations regarding the selection of a single sensor approach or sensor combination that fulfills a minimum requirement for practical mangrove mapping and inventory purposes (e.g. mangrove and non-mangrove areas, varying stocking density, dominant species composition and impact of human activities). Both their technical capabilities and their potentials are presented in correlation with the existing ground conditions.Asian Institute of Technology Bangkok, Thailand; National Research Council of Thailand Bangkok, Thailand; Royal Forestry Department Bangkok, Thailand     

Dynamics of biochemical and morphophysiological changes during zygotic embryogenesis in <Emphasis Type="Italic">Acca sellowiana</Emphasis> (Berg.) Burr.

Acca sellowiana (Berg.) Burr. is a native Myrtaceae from southern Brazil and Uruguay, now the subject of a domestication and breeding program. Biotechnological tools have been used to assist in this program. The establishment of a reliable protocol of somatic embryogenesis has been pursued, with a view to capturing and fixing genetic gains. The rationale behind this work relies on the fact that deepening comprehension of the general metabolism of zygotic embryogenesis may certainly improve the protocol for somatic embryogenesis. Thus, in the present work we studied the accumulation of protein, total sugars, starch, amino acids, polyamines (PAs), IAA and ABA, in different stages of A. sellowiana zygotic embryogenesis. Starch is the predominant storage compound during zygotic embryo development. Increased synthesis of amino acids in the cotyledonary stage, mainly of asparagine, was observed throughout development. Total free PAs showed increased synthesis, whereas total conjugated PAs were mainly observed in the early developmental stages. IAA decreased and ABA increased with the progression from early to late embryogenesis. Besides providing basic information on the morphophysiological and biochemical changes of zygotic embryogenesis, the results here obtained may provide adequate strategies towards the modulation of somatic embryogenesis in this species as well as in other woody angiosperms.