Zinc efficiency is correlated with enhanced expression and activity of zinc-requiring enzymes in wheat

Zinc (Zn) is an essential micronutrient for plants. The ability of plants to maintain significant yields under low Zn is termed Zn efficiency (ZE) and its genetic and mechanistic basis is still not well understood. Previously, we showed that root Zn uptake did not play a role in ZE. In the current study, Zn-efficient and -inefficient wheat (Triticum aestivum) genotypes were grown for 13 d in chelate buffer nutrient solutions at low (0.1 pM), sufficient (150 pM), and high (1 microM) Zn(2+) activities and analyzed for root-to-shoot translocation of Zn, subcellular leaf Zn distribution, and activity and expression of the Zn-requiring enzymes in leaves. No correlation between ZE and Zn translocation to the shoot was found. Furthermore, total and water-soluble concentrations of leaf Zn were not associated with ZE, and no differences in subcellular Zn compartmentation were found between Zn-efficient and -inefficient genotypes. However, the expression and activity of the Zn-requiring enzymes copper (Cu)/Zn superoxide dismutase (SOD) and carbonic anhydrase did correlate with differences in ZE. Northern analysis suggested that Cu/ZnSOD gene expression was up-regulated in the Zn-efficient genotype, Kirgiz, but not in inefficient BDME. Under Zn deficiency stress, the very Zn-efficient genotype Kirgiz and moderately Zn-efficient Dagdas exhibited an increased activity of Cu/ZnSOD and carbonic anhydrase when compared with Zn-inefficient BDME. These results suggest that Zn-efficient genotypes may be able to maintain the functioning of Zn-requiring enzymes under low Zn conditions; thus, biochemical Zn utilization may be an important component of ZE in wheat.     

Induction of volatile terpene biosynthesis and diurnal emission by methyl jasmonate in foliage of Norway spruce

Terpenoids are characteristic constitutive and inducible defense chemicals of conifers. The biochemical regulation of terpene formation, accumulation, and release from conifer needles was studied in Norway spruce [Picea abies L. (Karst)] saplings using methyl jasmonate (MeJA) to induce defensive responses without inflicting physical damage to terpene storage structures. MeJA treatment caused a 2-fold increase in monoterpene and sesquiterpene accumulation in needles without changes in terpene composition, much less than the 10- and 40-fold increases in monoterpenes and diterpenes, respectively, observed in wood tissue after MeJA treatment (D. Martin, D. Tholl, J. Gershenzon, J. Bohlmann [2002] Plant Physiol 129: 1003-1018). At the same time, MeJA triggered a 5-fold increase in total terpene emission from foliage, with a shift in composition to a blend dominated by oxygenated monoterpenes (e.g. linalool) and sesquiterpenes [e.g. (E)-beta-farnesene] that also included methyl salicylate. The rate of linalool emission increased more than 100-fold and that of sesquiterpenes increased more than 30-fold. Emission of these compounds followed a pronounced diurnal rhythm with the maximum amount released during the light period. The major MeJA-induced volatile terpenes appear to be synthesized de novo after treatment, rather than being released from stored terpene pools, because they are almost completely absent from needle oleoresin and are the major products of terpene synthase activity measured after MeJA treatment. Based on precedents in other species, the induced emission of terpenes from Norway spruce foliage may have ecological and physiological significance.     

Parent-offspring conflict theory,signaling of need,and weight gain in early life

Human growth in early life has major implications for fitness. During this period, the mother regulates the growth of her offspring through placental nutrition and lactation. However, parent-offspring conflict theory predicts that offspring are selected to demand more resources than the mother is selected to provide. This general issue has prompted the development of begging theory, which attempts to find the optimal levels of offspring demand and parental provisioning. Several models have been proposed to account for begging behavior, whether by biochemical or behavioral pathways, including: (1) blackmail of parents; (2) scramble competition between multiple offspring; (3) honest signaling of nutritional need; and (4) honest signaling of offspring worth. These models are all supported by data from nonhuman animals, with species varying according to which model is relevant. This paper examines the evidence that human suckling and crying signal nutritional demand, need, and worth to the mother. While suckling provides hormonal stimulation of breast milk production and signals hunger, crying fulfills a different role, with evidence suggesting that it signals both worth and need for resources (nutrition and thermoregulation). The role of signaling in nutritional demand is examined in the context of three common health problems that have traditionally been assumed to have physiological rather than behavioral causes: excess weight gain, failure to thrive, and colic. The value of such an evolutionary approach lies in its potential to enhance behavioral management of these conditions.     

High frequency of skin reactions in patients with leishmaniasis treated with meglumine antimoniate contaminated with heavy metals: a comparative approach using historical controls

We analyzed data from historical controls treated with meglumine antimoniate to compare the frequency of adverse events observed in patients with cutaneous leishmaniasis treated with the same dose of meglumine antimoniate contaminated with heavy metals in an endemic area of the State of Bahia, Brazil. Group A patients were treated in 2000 with the drug produced by Eurofarma Laborat rios Ltda., S o Paulo, Brazil (lot A) and group B patients were treated in 1996 with the reference drug produced by Rhodia Farma Ltda., S o Paulo, Brazil (lot B). We observed an unusual higher frequency of skin reactions in group A patients. However, all type of adverse events observed in group A were also observed in group B. The physico-chemical analysis of these lots revealed that lot A had lower pH and higher concentration of total and trivalent antimony, lead, cadmium, and arsenic. Our findings suggest that the skin reactions could be attributed to heavy metal contamination of lot A.     

Epidemiologic determinants of aural abscessation in free-living eastern box turtles (Terrapene carolina) in Virginia

Epidemiologic determinants of 46 cases of aural abscessation in free-living eastern box turtles (Terrapene carolina) admitted to the Wildlife Center of Virginia (Virginia, USA) from 1991 to 2000 were evaluated. County human population density, year and season of admission, weight, and sex did not affect the risk for box turtles to develop aural abscessation. Counties with cases of aural abscessation were not randomly distributed, but rather were clustered into two multi-county regions. Geographic location was the only risk factor associated with aural abscessation in box turtles found in this study. Possible etiologies could include chronic infectious disease, malnutrition, or chronic exposure to environmental contamination with organochlorine compounds.     

Characterization of the argA gene required for arginine biosynthesis and syringomycin production by Pseudomonas syringae pv. syringae

Two types of necrosis-inducing lipodepsipeptide toxins, called syringomycin and syringopeptin, are major virulence factors of Pseudomonas syringae pv. syringae strain B301D. A previous study showed that a locus, called syrA, was required for both syringomycin production and plant pathogenicity, and the syrA locus was speculated to encode a regulator of toxin production. In this study, sequence analysis of the 8-kb genomic DNA fragment that complements the syrA phenotype revealed high conservation among a broad spectrum of fluorescent pseudomonads. The putative protein encoded by open reading frame 4 (ORF4) (1,299 bp) in the syrA locus region exhibited 85% identity to ArgA, which is involved in arginine biosynthesis in Pseudomonas aeruginosa. Growth of strain W4S2545, the syrA mutant, required supplementation of N minimal medium with arginine. Similarly, syringomycin production of syrA mutant W4S2545 was restored by the addition of arginine to culture media. Furthermore, the insertion of Tn5 in the genome of the syrA mutant W4S2545 was localized between nucleotides 146 and 147 in ORF4, and syringomycin production was complemented in trans with the wild-type DNA fragment containing intact ORF4. These results demonstrate that the syrA locus is the argA gene of P. syringae pv. syringae and that argA is directly involved in arginine biosynthesis and therefore indirectly affects syringomycin production because of arginine deficiency.     

Some possible codes for encrypting data in DNA

Three codes are reported for storing written information in DNA. We refer to these codes as the Huffman code, the comma code and the alternating code. The Huffman code was devised using Huffman's algorithm for constructing economical codes. The comma code uses a single base to punctuate the message, creating an automatic reading frame and DNA which is obviously artificial. The alternating code comprises an alternating sequence of purines and pyrimidines, again creating DNA that is clearly artificial. The Huffman code would be useful for routine, short-term storage purposes, supposing – not unrealistically – that very fast methods for assembling and sequencing large pieces of DNA can be developed. The other two codes would be better suited to archiving data over long periods of time (hundreds to thousands of years).     

Role of ethylene in postharvest quality of cut oriental lily ‘Stargazer’

The effects of endogenous and exogenous C₂H₄ and C₂H₄ inhibitors on the postharvest leaf and flower quality of Oriental lily Stargazer were investigated. Endogenous C₂H₄ was not produced by freshly harvested excised leaves or flowers. Treatment of freshly harvested excised flowers, buds, leaves, and intact cut stems with C₂H₄ concentrations as high as 10 µl·l^–1 did not affect bud opening or longevity or the development of leaf yellowing. Therefore, treatment with anti-C₂H₄ compounds, such as silver thiosulfate (STS) and 1-methylcyclopropene (1-MCP), did not improve the quality of the flowers. Data thus indicate that freshly harvested Stargazer were not sensitive to C₂H₄. Sensitivity of Stargazer to C₂H₄, however, increased dramatically following cold storage, as exposure of cold-stored stems to C₂H₄ concentrations as low as 0.3 µl·l^–1 significantly affected bud opening. The development of leaf yellowing on cold-stored stems was not affected by the exogenous C₂H₄. Pretreating cold-stored stems with 1-MCP significantly reduced blasting of small buds that failed to develop due to carbohydrate depletion and reduced the percentage of buds that did not fully open. Concurrently, 1-MCP did not affect the quality of the leaves. These data indicate that sensitivity of cut lilies to C₂H₄ differs following cold storage and that 1-MCP is a more suitable anti-C₂H₄ compound than STS. Furthermore, studies on endogenous C₂H₄ production revealed that, while C₂H₄ was not detected in freshly harvested buds and leaves, it was produced by both following cold storage. The latter produced C₂H₄ at a higher rate than the former. Results of this study clearly indicate that there are two situations in which lilies will benefit from pretreatment with an anti-C₂H₄ compound (1) when cut stems contain buds that are marginally small for opening and (2) when cut stems will be cold stored before marketing.     

Hydrosoluble formazan XTT: its application to natural products drug discovery for Leishmania

A colorimetric method for measuring the viability of Leishmania promastigotes is described that is based on the reduction of the tetrazolium salt, XTT, to a water-soluble formazan. Values obtained by the XTT method correlated well with parasite number (r=0.965) and with methods that rely upon the reduction of MTT or MTS (r=0.96 and 0.97, respectively). The IC(50) values obtained by XTT method with amphotericin-B, miltefosine and ketoconazole were similar to those previously reported by other methods. The XTT method proved to be a reliable and convenient method for the screening of methanolic extracts from 1059 plants and was used for the bioassay-guided fractionation of the alkaloid aegeline from Sarcorhachis naranjoana.     

The relevance of alternative RNA splicing to pharmacogenomics

The importance of alternative RNA splicing in the generation of genetic diversity is now widely accepted. This article highlights how alternative RNA splicing can have an impact on drug efficacy and safety, and demonstrates its potential pharmacogenomic value. The analysis of the repertoire of alternative RNA splicing events could potentially identify markers of pharmacogenomic relevance with high sensitivity and specificity and also provides a route through which genes can be selected for single nucleotide polymorphism (SNP) genotyping. Recent methodological advances, including microarray and splice-dedicated expression profiling, have made it possible to perform high-throughput alternative splicing analyses.