Green Synthesized Silver Nanoparticles Using Lactobacillus Acidophilus as an Antioxidant,Antimicrobial, and Antibiofilm Agent Against Multi-drug Resistant Enteroaggregative Escherichia Coli

Probiotics and Antimicrobial Proteins - The present study was envisaged to employ the green synthesis and characterization of silver nanoparticles (AgNPs) using the potential probiotic strain...     

Ancient vertebrate conserved noncoding elements have been evolving rapidly in teleost fishes

Vertebrate genomes contain thousands of conserved noncoding elements (CNEs) that often function as tissue-specific enhancers. In this study, we have identified CNEs in human, dog, chicken, Xenopus, and four teleost fishes (zebrafish, stickleback, medaka, and fugu) using elephant shark, a cartilaginous vertebrate, as the base genome and investigated the evolution of these ancient vertebrate CNEs (aCNEs) in bony vertebrate lineages. Our analysis shows that aCNEs have been evolving at different rates in different bony vertebrate lineages. Although 78-83% of CNEs have diverged beyond recognition ("lost") in different teleost fishes, only 24% and 40% have been lost in the chicken and mammalian lineages, respectively. Relative rate tests of substitution rates in CNEs revealed that the teleost fish CNEs have been evolving at a significantly higher rate than those in other bony vertebrates. In the ray-finned fish lineage, 68% of aCNEs were lost before the divergence of the four teleosts. This implicates the "fish-specific" whole-genome duplication in the accelerated evolution and the loss of a large number of both copies of duplicated CNEs in teleost fishes. The aCNEs are rich in tissue-specific enhancers and thus many of them are likely to be evolutionarily constrained cis-regulatory elements. The rapid evolution of aCNEs might have affected the expression patterns driven by them. Transgenic zebrafish assay of some human CNE enhancers that have been lost in teleosts has indicated instances of conservation or changes in trans-acting factors between mammals and fishes.     

Conservation of all three p53 family members and Mdm2 and Mdm4 in the cartilaginous fish

Analysis of the genome of the elephant shark (Callorhinchus milii), a member of the cartilaginous fishes (class Chondrichthyes), reveals that it encodes all three members of the p53 gene family, p53, p63 and p73, each with clear homology to the equivalent gene in bony vertebrates (class Osteichthyes). Thus, the gene duplication events that lead to the presence of three family members in the vertebrates dates to before the Silurian era. It also encodes Mdm2 and Mdm4 genes but does not encode the p19^Arf gene. Detailed comparison of the amino acid sequences of these proteins in the vertebrates reveals that they are evolving at highly distinctive rates, and this variation occurs not only between the three family members but extends to distinct domains in each protein.Key words: p53, p63, p73, Mdm2, Mdm4, elephant shark     

Captures of oriental fruit moth, <Emphasis Type="Italic">Grapholita molesta</Emphasis> (Lepidoptera: Tortricidae), in traps baited with host-plant volatiles in Chile

Studies in Australia and China identified host-plant volatile blends from peach and pear that captured relatively high numbers of Grapholita molesta (Busck). To determine if these blends are attractants in other countries and relative to each other, the two host-plant blends, a laboratory blend identified in Switzerland, and a new “total blend” made by mixing components of all three blends, were field-tested in Chile for the first time. The same solvent type, concentrations, and dispensers as in the original studies, plus an additional concentration and solvent, were used. Only the Swiss blend at the low n-hexane concentration captured significantly more males than the solvent traps, albeit in very low numbers (1.46 ± 1.46, mean ± SEM males/trap/week). Furthermore, host-plant blends decreased male captures in sex pheromone traps, and the effect was dose-dependent for the Chinese and total blends. A laboratory flight tunnel test confirmed the lack of G. molesta male response to the Australian, Chinese, and Swiss plant blends. In the flight tunnel, however, the males responded sooner and in higher numbers to mixtures of sex pheromone with host-plant blends than they did to the sex pheromone alone.     

Evolution and diversity of fish genomes

The ray-finned fishes ('fishes') vary widely in genome size, morphology and adaptations. Teleosts, which comprise approximately 23600 species, constitute >99% of living fishes. The radiation of teleosts has been attributed to a genome duplication event, which is proposed to have occurred in an ancient teleost. But more evidence is required to support the genome-duplication hypothesis and to establish a causal relationship between additional genes and teleost diversity. Fish genomes seem to be 'plastic' in comparison with other vertebrate genomes because genetic changes, such as polyploidization, gene duplications, gain of spliceosomal introns and speciation, are more frequent in fishes.     

Genetic basis of tetrodotoxin resistance in pufferfishes

Tetrodotoxin (TTX) is a highly potent neurotoxin that selectively binds to the outer vestibule of voltage-gated sodium channels. Pufferfishes accumulate extremely high concentrations of TTX without any adverse effect. A nonaromatic amino acid (Asn) residue present in domain I of the pufferfish, Takifugu pardalis, Na v1.4 channel has been implicated in the TTX resistance of pufferfishes . However, the effect of this residue on TTX sensitivity has not been investigated, and it is not known if this residue is conserved in all pufferfishes. We have investigated the genetic basis of TTX resistance in pufferfishes by comparing the sodium channels from two pufferfishes (Takifugu rubripes [fugu] and Tetraodon nigroviridis) and the TTX-sensitive zebrafish. Although all three fishes contain duplicate copies of Na v1.4 channels (Na v1.4a and Na v1.4b), several substitutions were found in the TTX binding outer vestibule of the two pufferfish channels. Electrophysiological studies showed that the nonaromatic residue (Asn in fugu and Cys in Tetraodon) in domain I of Na v1.4a channels confers TTX resistance. The Glu-to-Asp mutation in domain II of Tetraodon channel Na v1.4b is similar to that in the saxitoxin- and TTX-resistant Na+ channels of softshell clams . Besides helping to deter predators, TTX resistance enables pufferfishes to selectively feed on TTX-bearing organisms.     

Compact intergenic regions of the pufferfish genome facilitate isolation of gene promoters: characterization of Fugu 3'-phosphoadenosine 5'-phosphosulfate synthase 2 (fPapss2) gene promoter function in transgenic Xenopus

The highly compact nature of the pufferfish (Fugu rubripes) genome renders it a useful tool not only for annotating coding regions within vertebrate genomes, but also for the identification of sequences important to gene regulation. Indeed, owing to this compaction it will be feasible in many instances to initiate analyses using entire intergenic regions when mapping gene promoters; a strategy that is very rarely feasible with the expanded genomes of other species. Stemming from our interest in studying promoters expressed in chondrocytes, we selected for study the intergenic region upstream of Fugu 3'-phosphoadenosine 5'-phosphosulfate synthase 2, fPapss2, a gene required for the normal development of cartilage extracellular matrix. Functional characterization of the entire fPapss2 5' intergenic region was carried out by monitoring expression of the enhanced green fluorescent protein (EGFP) gene reporter in the developing cartilage of transgenic Xenopus laevis. By evaluating a series of 5' intergenic region deletions we defined a minimal fPapss2 sequence of approximately 300 bp that was essential for EGFP expression in tadpole cartilage. This functional analysis of an entire Fugu intergenic region, combined with the efficiency of Xenopus transgenesis, serves as a model for the rapid characterization of evolutionarily-conserved regulatory regions of other pufferfish genes.