Effects of N-fertilizers,straw, and dry fallow on the nitrogen balance of a flooded soil planted with rice

Summary Nitrogen balance studies were made on rice (Oryza sativa) grown in flooded soil in pots. A low rate of fertilizer (5.64 mg N. kg⁻¹ soil) did not depress the N gain, but a high rate (99.72 mg N. kg⁻¹ soil) elminated the N gain. Soil N loss was negligible since¹⁵N applied as ammonium sulfate and thoroughly mixed with the soil was recovered from the soil-plant system after 3 crops. The observed N gain, therefore, was caused by N₂-fixation, not by a reduction of soil N loss. Straw enhanced N gain at the rate of 2–4 mg per g straw. However, this gain was not observed when soil N availability was high. Dry fallow between rice crops decreased the N gain.     

Pseudomonas aeruginosa acid phosphatase and cholinesterase induced by choline and its metabolic derivatives may contain a similar anionic peripheral site

Summary Different compounds derived from choline, and obtained by demethylation or by oxidation of the primary alcohol group with subsequent N-demethylation, were tested as inducer agents of acid phosphatase and cholinesterase in Ps. aeruginosa. It was found that betaine and dimethylglycine were the most effective inducers of both enzyme activities. These metabolites including choline itself, were not inducers of acid phosphatase and cholinesterase in other Gram-negative bacteria such as: Escherichia coli, Salmonella typhimurium, Shigella flexneri, Enterobacter liquefacciens and Proteus mirabilis. The acid phosphatase activities found in these bacteria were not inhibited in vitro by choline, betaine and phosphorylcholine. From these results it may be concluded that the acid phosphatase activity from Ps. aeruginosa is different from the same activity observed in the other bacteria. In addition, it is also shown that Ps. aeruginosa acid phosphatase and cholinesterase were inhibited by a number of compounds containing a positively charged amino group, with methyl or ethyl groups bound to it. These results seem to confirm that Ps. aeruginosa acid phosphatase and cholinesterase may contain a similar anionic site.     

Nitrogen fixation throughout growth,and varietal differences in nitrogen fixation by the rhizosphere of rice planted in pots

Summary The nitrogen-fixing activity in the rhizospheres of various rices was measured by the acetylene-reduction method throughout plant growth in green-house pots. The activity began to increase 4 weeks after transplanting, increased until heading stage, then decreased. The concentrations of exchangeable ammonium and sugars in the soil were not related to the variation of nitrogen-fixing activity during rice growth.The nitrogen-fixing activities in the rhizospheres of 41 rice varieties in pots were measured to discover varietal differences. Levels of nitrogen fixation were highly correlated with the rices' dry root weight at heading stage.     

Pure red cell hypoplasia associated with long-arm deletion of chromosome 5

Summary A further instance of the new hematologic entity of pure red cell hypoplasia with deletion of the long arm of a chromosome 5(5q-) was seen in a 59-year-old white male. Examination of the bone marrow showed depressed erythroid cells with normal granulocytic and megakaryocytic precursors. Chromosomal analysis showed deletion of a chromosome 5 without any apparent translocation. This karyotype may be associated with acute leukemia.     

Epidemiological Characterization of Influenza A(H1N1)pdm09 Cases from 2009 to 2010 in Baguio City,the Philippines

Background

Baguio City, Philippines experienced its first influenza A(H1N1)pdm09 [A(H1)pdm09] case in May 2009. In spite of numerous reports describing the epidemiological and clinical features of A(H1)pdm09 cases, there are no studies about A(H1)pdm09 epidemiology in the Philippines, where year-round influenza activity was observed.

Objectives

We aimed to investigate the epidemiological and clinical features of A(H1)pdm09 in pandemic and post-pandemic periods.

Methods

Data were collected under enhanced surveillance of influenza-like illness (ILI) and severe acute respiratory infection (SARI) from January 2009 to December 2010. RT-PCR was used to detect A(H1)pdm09, following the protocol of the United States Centers for Disease Control and Prevention. The reproduction number was computed as a simple exponential growth rate. Differences in proportional and categorical data were examined using chi-square test or Fishers’ exact test.

Results and Conclusions

The outbreak was observed from week 25 to 35 in 2009 and from week 24 to 37 in 2010. The highest proportion of cases was among children aged 5–14 years. The number of ILI outpatients was 2.3-fold higher in 2009 than in 2010, while the number of inpatients was 1.8-fold higher in 2009. No significant difference in gender was observed during the two periods. The clinical condition of all patients was generally mild and self-limiting, with only 2 mortalities among inpatients in 2009. The basic reproduction number was estimated as 1.16 in 2009 and 1.05 in 2010 in the assumption of mean generation time as 2.6 days. School children played a significant role in facilitating influenza transmission.     

Engineering production of antihypertensive peptides in plants

To date, a number of antihypertensive peptides (AHPs) have been identified. Most of these are derived from proteins present in common edible consumables, including milk, egg, and plant foods. Consumption of these foods serves as means of AHP delivery and thus contributing favorable health benefits. It is hypothesized that food crops, either over-expressing AHP precursor proteins or producing particular peptides as heterologous components, may serve as viable vehicles for production and delivery of functional foods as alternative hypertension therapies. In recent years, genetic engineering efforts have been undertaken to add value to functional foods. Pioneering approaches have been pursued in several crop plants, such as rice and soybean. In this review, a summary of current tools used for discovery of new AHPs, as well as strategies and perspectives of capitalizing on these AHPs in genetic engineering efforts will be presented and discussed. The implications of these efforts on the development of functional foods for preventing and treating hypertension are also presented.     

50 years of the Revista de Biologia Tropical: its contribution to the development of the Geo-Paleontology

The geosciences contribution along the 50 years of the Revista de Biología Tropical had been scarcity and episodic. Until now there are 2374 papers but only 21 (0.88%) have some relation with geological sciences. It's possible to recognize two periods with geological contributions, one between 1963 and 1978. It's appropriate to underline the importance of the biologist L. D. Gómez with his contributions about Costa Rican Paleobotanic in this period. The other period includes from 1988 to the present, and it's typified by an increase of biologist and geologist participation in different topics regarding with geosciences. Foreign and national researches are in the same ratio and belong from several countries like Costa Rica, México and Dominican Republic. The subjects are concerning mainly about fossil taxonomy (Paleontology: 81%), only 19% are related with geological topics. Such distribution could be explained because the affinity between the fossil studies and the biological sciences.     

Plasma levels of GH and PRL and concentrations in the fluids of bovine ovarian cysts and follicles

Prolactin and GH have been detected within the ovary, and it has become increasingly evident that they have a role as intrafollicular regulatory factors. The aim of the present work was to gain an insight into the elements influencing intraovarian GH and PRL in bovine species and to see whether cystic degeneration was accompanied by abnormal bovine GH (bGH) and PRL (bPRL) plasma patterns. We followed the relationships between plasma and ovarian fluid bGH and bPRL concentrations over an entire year in Friesian cows whose ovaries showed distinct types of structures. To assess the presence of bGH and bPRL within ovarian cells, we assayed selected ovarian structures by immunohistochemistry. The results demonstrated that: 1) plasma and ovarian fluid hormonal concentrations were independent, and their ratio was independent of the ovarian structure classes, subclasses and period of the year; 2) in the majority of the cows the concentration of bGH in ovarian fluid was no more than 80% of the level in plasma, whereas in about half the animals bPRL concentrations were higher in the ovary than in peripheral plasma; 3) mean bPRL concentrations in ovarian fluids were significantly higher in summer than in winter; 4) immunoreactive bGH and bPRL were present within granulosa and luteal cells. Thus, it is suggested that in the cow bGH and bPRL levels in the ovary might be regulated in some way independently of the pituitary.     

Genome-Wide Association Mapping for Yield and Other Agronomic Traits in an Elite Breeding Population of Tropical Rice (Oryza sativa)

Genome-wide association mapping studies (GWAS) are frequently used to detect QTL in diverse collections of crop germplasm, based on historic recombination events and linkage disequilibrium across the genome. Generally, diversity panels genotyped with high density SNP panels are utilized in order to assay a wide range of alleles and haplotypes and to monitor recombination breakpoints across the genome. By contrast, GWAS have not generally been performed in breeding populations. In this study we performed association mapping for 19 agronomic traits including yield and yield components in a breeding population of elite irrigated tropical rice breeding lines so that the results would be more directly applicable to breeding than those from a diversity panel. The population was genotyped with 71,710 SNPs using genotyping-by-sequencing (GBS), and GWAS performed with the explicit goal of expediting selection in the breeding program. Using this breeding panel we identified 52 QTL for 11 agronomic traits, including large effect QTLs for flowering time and grain length/grain width/grain-length-breadth ratio. We also identified haplotypes that can be used to select plants in our population for short stature (plant height), early flowering time, and high yield, and thus demonstrate the utility of association mapping in breeding populations for informing breeding decisions. We conclude by exploring how the newly identified significant SNPs and insights into the genetic architecture of these quantitative traits can be leveraged to build genomic-assisted selection models.