Effect of toluidine blue on pollen germination and pollen tube growth

Toluidine blue is known to induce gynogenic haploids in significant numbersin Populus]. Because the efficacy of a chemical in inducing gynogenesis depends largely on its effeot on pollen germination, on pollen tube growth, and on male gamete formation, the effect of toluidine blue (0, 1, 10 and 100 mgl-1) on these processes was studied in treated pistils ofSolatium nigrum (4 X), as well as on cultured pollen grains ofS. nigrum andTrigonella foenumgraecum. Irrespective of the time of application, toluidine blue (1 and 10 mg I-1) had no effect on pollen germination or pollen tube growth in pistils ofS. nigrum; at 100 mg I-1 it invariably inhibited both the processes. Almost similar responses were elicited by cultured pollen grains. InT. foenum-graecum toluidine blue had no effeot on pollen germination and suppressed tube growth. Gamete formation was inhibited, to various degrees, at all the concentrations tested; at 100 ing I-1 hardly any pollen tube showed gamete formation. Based on our results, and those on other systems, the potentiality of toluidine blue as an inducer of gynogenesis has been analysed.     

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...     

Sequencing and comparative analysis of fugu protocadherin clusters reveal diversity of protocadherin genes among teleosts

Background  

The synaptic cell adhesion molecules, protocadherins, are a vertebrate innovation that accompanied the emergence of the neural tube and the elaborate central nervous system. In mammals, the protocadherins are encoded by three closely-linked clusters (α, β and γ) of tandem genes and are hypothesized to provide a molecular code for specifying the remarkably-diverse neural connections in the central nervous system. Like mammals, the coelacanth, a lobe-finned fish, contains a single protocadherin locus, also arranged into α, β and γ clusters. Zebrafish, however, possesses two protocadherin loci that contain more than twice the number of genes as the coelacanth, but arranged only into α and γ clusters. To gain further insight into the evolutionary history of protocadherin clusters, we have sequenced and analyzed protocadherin clusters from the compact genome of the pufferfish, Fugu rubripes.     

Production and characterization of interspecific hybrids between Brassica maurorum and crop brassicas

 Seven interspecific hybrids were produced between Brassica maurorum (♀), a wild species resistant to Alternaria blight and white rust, and all the monogenomic (B. campestris, B. nigra and B. oleracea) and digenomic (B. juncea, B. napus and B. oleracea) crop brassicas (♂) through embryo rescue. The hybrids were confirmed by means of morphological and cytological studies. All the hybrids were pollen-sterile. Amphidiploids were induced in three of the hybrids: B. maurorum×B. napus, B. maurorum×B. carinata, B. maurorum×B. nigra. The hybrids were also confirmed through DNA analyses for nuclear and organelle genomes using RAPD and RFLP techniques. Received: 31 July 1998 / Accepted: 14 August 1998     

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     

Emergence of 13_A2 Blue Lineage of Phytophthora infestans was Responsible for Severe Outbreaks of Late Blight on Tomato in South‐West India

Prior to 2007, late blight was not reported as a serious threat to tomato cultivation in India although the disease has been known on potato since 1953. During the July–December cropping season of 2009 and 2010, severe late blight epidemics were observed in Karnataka state of India, causing crop losses up to 100%. Nineteen Phytophthora isolates, recovered from late blight affected tomato tissues from different localities in Karnataka state between 2009 and 2010, were identified as Phytophthora infestans based on morphology, a similarity search of ITS sequences at GenBank and species‐specific PCR using PINF/ITS5 primer pair. The isolates were further assessed for metalaxyl sensitivity, mating type, mitochondrial DNA (mtDNA) haplotype, DNA fingerprinting patterns based on simple sequence repeats (SSR) and RFLPs using the RG57 probe and aggressiveness on tomato. All isolates were metalaxyl resistant, A2 mating type, mtDNA haplotype Ia and had identical SSR and RG57 fingerprints and highly aggressive on tomato. The phenotypic and genotypic characters of isolates examined in this study were found to be similar to that of 13_A2 genotype of P. infestans population reported in Europe. Thus, appearance of new population similar to 13_A2 genotype was responsible for severe late blight epidemics on tomato in South‐West India.     

Fungal foliar diseases in Withania somnifera and its effect on secondary metabolites

Withania somnifera is a promising revitalizing medicinal herb. The plant is affected by foliar diseases in Lakkavalli forest region of Bhadra Wildlife Sanctuary. The symptomatology of foliar fungal disease incidence, severity and distribution in the study area was examined during 2006–2009. The seedborne nature and transmission of the causal pathogen and its management with seed dressing fungicides were studied. The results of the study indicated that Alternaria alternata caused severe leaf spot disease, while Myrothecium roridum and Fusarium oxysporum caused minor diseases. Based on the internal transcribed spacer (ITS1 and ITS2) regions of rDNA, the major pathogen was identified as A. alternata. The disease is homogeneously distributed in Lakkavalli forest region and high severity is recorded during November. Alternaria alternata and Fusarium oxysporum were the dominant seedborne pathogens that are transmitted to seedlings. Among the seed dressing fungicides used, Hyzeb was the most effective, followed by Captra, Antracol and Bavistin, in reducing the incidence of A. alternata and other seedborne fungi. The infected W. somnifera foliages had decreased steroids and alkaloids and increased phenolics and flavonoids. Analysis of alkaloids in diseased foliages by high performance thin layer chromatography indicated the occurrence of transformed compounds at R_f = 0.1, 0.77 (254 nm) and 0.2 (366 nm).     

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.