Characteristics of Plasmon Resonance of Gold Nanoparticles in Three-Layer Systems AuNP-Al2O3-PdO(Pd)

Plasmonics - This work deals with plasmonic properties of gold nanoparticles (NP) in the three-layers system comprising this NP, isolating (Al2O3), and conducting (PdO, Pd) layers. A sequence of...     

Low nucleotide diversity at the pal1 locus in the widely distributed Pinus sylvestris.

Nucleotide polymorphism in Scots pine (Pinus sylvestris) was studied in the gene encoding phenylalanine ammonia-lyase (Pal, EC 4.3.1.5). Scots pine, like many other pine species, has a large current population size. The observed levels of inbreeding depression suggest that Scots pine may have a high mutation rate to deleterious alleles. Many Scots pine markers such as isozymes, RFLPs, and microsatellites are highly variable. These observations suggest that the levels of nucleotide variation should be higher than those in other plant species. A 2,045-bp fragment of the pal1 locus was sequenced from five megagametophytes each from a different individual from each of four populations, from northern and southern Finland, central Russia, and northern Spain. There were 12 segregating sites in the locus. The synonymous site overall nucleotide diversity was only 0.0049. In order to compare pal1 with other pine genes, sequence was obtained from two alleles of 11 other loci (total length 4,606 bp). For these, the synonymous nucleotide diversity was 0.0056. These estimates are lower than those from other plants. This is most likely because of a low mutation rate, as estimated from between-pine species synonymous site divergence. In other respects, Scots pine has the characteristics of a species with a large effective population. There was no linkage disequilibrium even between closely linked sites. This resulted in high haplotype diversity (14 different haplotypes among 20 sequences). This could also give rise to high per locus diversity at the protein level. Divergence between populations in the main range was low, whereas an isolated Spanish population had slightly lower diversity and higher divergence than the remaining populations.     

Physiological comparison of cells with high and low alcohol dehydrogenase activities in bacterial populations consuming ethanol

Measuring the physiological heterogeneity of natural and industrial microbial populations is essential to studying, modelling and monitoring of microbial populations. It was discovered that populations of Escherichia coli and Bacillus megaterium growing in medium with ethanol as an external source of energy have two actively respiring but physiologically different subpopulations. Cells of one subpopulation have negligibly low alcohol dehydrogenase (ADH) activity (ADH-L cells) and cells of the other have high ADH activity (ADH-H cells). The subpopulation of ADH-H bacterial cells was measured using 10 min incubations of cells in a 1% solution of allyl alcohol for fast selective killing of cells with high activity of ADH and flow cytometry detection of dead cells after this incubation. The content of ADH-H cells during exponential phase of batch culture varied from 9 % to 90 % and lowered to zero for a few hours during starvation of the population. ADH-L cells are actively respiring cells and not depolarized cells. The simultaneous presence of ADH-L and ADH-H cells growing in the medium with ethanol can be explained by the fact that ADH-H cells oxidize actively external ethanol whereas ADH-L cells oxidize only intracellular storage carbohydrates. The method for enumeration of cells with high ADH activity can be used to monitor the heterogeneity of bacterial populations consuming ethanol as a sole source of carbon and energy.     

Isolation and characterization of mutated alcohol oxidases from the yeast <Emphasis Type="Italic">Hansenula polymorpha</Emphasis> with decreased affinity toward substrates and their use as selective elements of an amperometric biosensor

Background  

Accurate, rapid, and economic on-line analysis of ethanol is very desirable. However, available biosensors achieve saturation at very low ethanol concentrations and thus demand the time and labour consuming procedure of sample dilution.     

Goldfish can recover after short-term exposure to 2,4-dichlorophenoxyacetate: Use of blood parameters as vital biomarkers

This study investigated the effects of 2,4-dichlorophenoxyacetic acid (2,4-D), a widely used herbicide, on the metabolism of goldfish, Carassius auratus, using only vital (non-lethal) approaches. After 96 h exposure to 1, 10 or 100 mg/L of 2,4-D selected hematological (total hemoglobin and hematocrit) and biochemical (glucose content, aspartate transaminase and acetylcholinesterase activities) parameters were unchanged in blood of exposed fish. At 100 mg/L of 2,4-D lymphocyte numbers decreased by 8%, whereas promyelocyte and metamyelocyte numbers increased by 7- and 2-fold, respectively. Exposure to 100 mg/L of 2,4-D also elevated carbonyl protein levels (by 2-fold), triglyceride content (by 43%) and alanine transaminase activity (by 46%) in goldfish plasma. All of these hematological and biochemical parameters reverted to control values after a 96 h recovery period. These data indicate that 2,4-D has toxicological effects on goldfish that can be monitored with multiple diagnostic tests using non-lethal blood testing.