Effect of alkyl chain length on thermochromism of novel nitro compounds

A series of novel nitro compounds containing different alkyl chain length (x=2∼5), 1,5-bis(hydroxyalkylamino)-2,4-dinitrobenzene (BDBx), are synthesized and their thermochromic behavior is investigated by using differential scanning calorimetry and optical microscopy. All the BDBx crystals synthesized show yellow color at room temperature. BDBx (x=2∼4) samples display orange color even in the solid when heated above respective thermochromic transition temperature, while the yellow color of BDB5 changes to orange with melting. The orange color of BDBx crystals returns to yellow when cooled down to room temperature, indicating that the thermochromic behavior of BDBx is reversible. The thermochromic transition temperatures of BDBx crystals are found to be decreased with increasing the alkyl chain length, exhibiting evenodd fluctuation.     

Bacterial populations assimilating carbon from C-labeled plant residue in soil: Analysis by a DNA-SIP approach

In this study, ¹³C-labeled rice callus was prepared as a model material for rice straw and was subjected to a DNA-SIP (stable isotope probing) experiment in which the bacterial population was monitored in a soil sample containing decomposing dried callus. Rice callus (¹³C = 78%) contained the more water-soluble organic carbon and less cellulose and lignin carbon than rice straw. The callus in the soil was 37% decomposed after 56 d of incubation in upland moisture conditions. PCR-DGGE analysis demonstrated that the bacterial community in the soil with the callus changed over time, showing a distinct difference between the first (up to 7 d) and second (14 d and later) stages. After isopycnic centrifugation, DNA in the fractions with a buoyant density between 1.759 and 1.734 g ml⁻¹ was subjected to population analysis (¹³C-assimilating populations). Diverse groups of bacterial sequences were retrieved from the ¹³C-labeled DNA fractions: Actinobacteria, Bacilli, γ-Proteobacteria, Chloroflexi, Sphingobacteria, Flavobacteria, Clostridia, Acidobacteria, Cyanobacteria and Candidate Division. Bacilli were detected mainly in the first stage, and Actinobacteria were detected throughout the incubation period. Several DGGE bands in the light fractions became more prominent in the soil with callus, which suggested that the addition of callus promoted the growth of bacteria that fed on soil organic matter, including α-Proteobacteria, γ-Proteobacteria, Bacilli, Actinobacteria, Nitrospira and Gemmatimonadetes.     

Intragastric gavage with denatonium benzoate acutely induces neuronal activation in the solitary tract nucleus via the vagal afferent pathway

Natural toxic substances have a bitter taste and their ingestion sends signals to the brain leading to aversive oral sensations. In the present study, we investigated chronological changes in c-Fos immunoreactivity in the nucleus tractus solitarius (NTS) to study the bitter taste reaction time of neurons in the NTS. Equal volumes (0.5 mL) of denatonium benzoate (DB), a bitter tastant, or its vehicle (distilled water) were administered to rats intragastrically. The rats were sacrificed at 0, 0.5, 1, 2, 4, 8, or 16 h after treatment. In the vehicle-treated group, the number of c-Fos-positive nuclei started to increase 0.5 h after treatment and peaked 2 h after gavage. In contrast, the number of c-Fos-positive nuclei in the DB-treated group significantly increased 1 h after gavage. Thereafter, the number of c-Fos immunoreactive nuclei decreased over time. The number of c-Fos immunoreactive nuclei in the NTS was also increased in a dose-dependent manner 1 h after gavage. Subdiaphragmatic vagotomy significantly decreased DB-induced neuronal activation in the NTS. These results suggest that intragastric DB increases neuronal c-Fos expression in the NTS 1 h after gavage and this effect is mediated by vagal afferent fibers.     

DNA fingerprinting: application to conservation of the CITES-listed dragon fish, Scleropages formosus (Osteoglossidae)

Since 1975,CITES has listed the dragon fish, Scleropages formosus, as anendangered species. In 1995, a captive-bred population was set upby a commercial fish farm with assistance from the PrimaryProduction Department in Singapore. Other farms in Indonesia andMalaysia followed suit. These populations have contributed to animmediate conservation of the species. Due to very high demandfor this ornamental fish, these venues may be its last sanctuary.DNA fingerprints of the dragon fish were obtained by different methods from the green, red and gold varieties grown in a Singapore fish farm to determine which method was most suitable in providing information on genetic variability. Because a DNA fingerprint is a pattern made up of DNA fragments that are resolved by electrophoresis, each individual has its own unique fingerprint due to a genetic make-up different from another individual. Thus, genetic variability was best studied by developing DNA fingerprints.Firstly, restriction fragment length polymorphisms (RFLPs) were obtained. DNA fragments formed by cleavage with nine restriction endonucleases used singly were hybridized individually to four non-radioactively labelled probes to give RFLPs. The RFLPs for each variety were similar and genomic DNA from each variety had many binding sites to the probes. This made differentiating RFLPs specific to individual varieties difficult. Secondly, random amplified polymorphic DNA (RAPD) fingerprints were developed. DNA fragments that were resolved on a denaturing polyacrylamide gel were hybridized to seven arbitrary primers used singly. RAPD fingerprints for each variety were different for each primer tested. The similarity index indicated low genetic variability between varieties. Lastly, DNA was screened for microsatellite loci which refer to short tandem repeats of two or three bases. The occurrence of other microsatellite loci, their chromosome location and frequency is being investigated while primers have been designed to detect more loci by the polymerase chain reaction. As this method provides undisputed and reproducible evidence of relatedness and stock identification, and can be applied for long-term management of domesticated populations through pedigree construction and evaluation of heterozygosity, it is the preferred choice to determine genetic variability     

Case studies and reviews. Vegetation zonation and invertebrate fauna in Pant-y-llyn,an unusual seasonal lake in South Wales,UK

• 1. Temporary waters have been relatively neglected in British nature conservation, due in part to paucity of survey and comparative assessment. Such water bodies hold distinctive and specialized biological communities, and the need for conservation measures at key localities is increasingly recognized in Europe.
• 2. An account of the vegetation and invertebrate fauna in Pant-y-llyn, a small temporary lake on Carboniferous Limestone in South Wales, is presented. Water levels in the basin reflect seasonal variation in the height of the local groundwater, and it fills to a depth of ca 3–4 m in winter but is almost completely dry in summer.
• 3. There is a clearly displayed sequence of bryophyte, herbaceous swamp and woody plant communities which occupy different depth zones in the basin.
• 4. The invertebrate community is dominated by microcrustaceans and a range of insect groups; adaptations for survival over the summer dry phase are considered.
• 5. It is concluded that the ecological characteristics and distinctive hydrological features of Pant-y-llyn closely resemble those of the Irish turloughs. Pant-y-llyn thus represents an important site for conservation as the only known example of this form of seasonal water body in Britain.

     

Antimicrobial Activity of Peptides Derived from Olive Flounder Lipopolysaccharide Binding Protein/Bactericidal Permeability-Increasing Protein (LBP/BPI)

We describe the antimicrobial function of peptides derived from the C-terminus of the olive flounder LBP BPI precursor protein. The investigated peptides, namely, ofLBP1N, ofLBP2A, ofLBP4N, ofLBP5A, and ofLBP6A, formed α-helical structures, showing significant antimicrobial activity against several Gram-negative bacteria, Gram-positive bacteria, and the yeast Candida albicans, but very limited hemolytic activities. The biological activities of these five analogs were evaluated against biomembranes or artificial membranes for the development of candidate therapeutic agents. Gel retardation studies revealed that peptides bound to DNA and inhibited migration on an agarose gel. In addition, we demonstrated that ofLBP6A inhibited polymerase chain reaction. These results suggested that the ofLBP-derived peptide bactericidal mechanism may be related to the interaction with intracellular components such as DNA or polymerase.     

Fluorescence polarization assay for the diagnosis of bovine brucellosis: adaptation to field use

A fluorescence polarization assay (FPA) was used to test whole blood samples prepared by mixing blood cells from cattle without exposure to Brucella abortus (B. abortus) with sera from animals with confirmed (bacteriologically) infection. A cut-off value between negative and positive values was initially established to be 87.2mP. This value was changed to 95mP to increase assay specificity without loss of sensitivity when testing blood samples from negative animals. The FPA technology was applied to whole blood samples in the field and to stored whole blood samples using two diluent buffers. Relative sensitivity and specificity values for the FPA performed in the field, based on buffered antigen plate agglutination test and competitive enzyme immunoassay results were 95.3 and 97.3%, respectively. However, to obtain maximum sensitivity and specificity, a cut-off value of 105mP was determined for fresh whole blood samples. The relative sensitivity and specificity values of the FPA when testing stored whole blood samples were 100% each using a 95mP cut-off.The usefulness of the FPA for testing whole blood samples in the field was demonstrated.     

Interaction of Phosphate and Salinity on the Growth and Yield of Rice (Oryza sativa L.)

The role of phosphorus application on growth and yield of rice under saline conditions was studied in a set of two experiments, one in nutrient and the other in soil culture. In experiment 1, the effect of inorganic phosphate (P_i) on the growth and ionic relations of four rice cultivars, varying in salt tolerance and phosphorus use efficiency, grown in nutrient solution with and without 50 mol m^?3 NaCl was measured in a 2 week trial. The growth of all rice cultivars was affected to different degrees due to external P, in the presence of salt. External P, concentration up to 100 μM in the presence of NaCl caused stimulation of all growth parameters (shoot, root, tillering capacity), above this concentration P, had an inhibitory effect. Salt-induced P toxicity was exhibited at a much lower P, concentration (10 μM) by the salt sensitive cultivar. Increasing the supply of phosphorus (from 1 to 100 μM P_i) to the saline medium tended to decrease the concentrations of Na¹ and CI in all cultivars except IR 1561. Shoot concentrations of these saline ions were much lower in the salt tolerant and moderately salt tolerant rice cultivars. Shoot P and Zn concentrations showed an increasing trend in the presence of external P, and salt in the rooting nr -idium but most strikingly P: Zn ratio was lower in salt tolerant and moderately salt tolerant cultivars. Significantly higher concentrations of Na⁺, P and CI, and lower concentrations of Zn, were determined in the shoots of salt sensitive cultivars when exposed to salt stress in the presence of P_i Results were confirmed in naturally salt-affected soils of two different types (saline-sodic and saline) where paddy yield of NIAB 6 (salt tolerant) and IR 1561 (salt sensitive) showed improvement through moderate phosphorus supply (18 kg P ha^?1).     

Use of microsatellite markers to detect quantitative trait loci in Yorkshire pigs

To identify genetic markers associated with economic traits in pigs, 157 microsatellite markers were examined in Yorkshire pigs. Thirty eight female Yorkshire pigs were initially examined and six of them were selected as progenitors; half were more than 1.5 standard deviations (SD) above the mean for average daily gain (ADG) and backfat thickness (BFT), and the remaining half were more than 1.5 SD below the mean. These pigs were then mated to male Duroc pigs, and 200 F2 pig offspring were examined for the association of specific alleles with ADG and BFT. To confirm the specific markers identified in the initial analysis, associations of significant markers with economic traits were further examined in 228 additional performance-tested purebred pigs. Twenty-five microsatellite markers were significantly associated with either ADG or BFT, and among these, 17 were associated with both traits. The markers with the highest association to ADG were also associated with BFT. Our study reveals that specific markers could be used to predict economic significance, and confirms several quantitative trait loci (QTL) identified in previous studies. However, further analysis with more closely-spaced microsatellite markers is required to refine predictive values for economic traits and positions of QTL that are reliable for actual phenotypic prediction.