Enzyme activities of agarwood (Aquilaria malaccensis Lamk.) stem under pathogenesis

Cellulase, pectinase, peroxidase and polyphenol oxidase activities were determined in healthy,naturally infected and inoculated agarwood (Aquilaria malaccensis) plant parts at varioustime intervals to study the changes in activities of these enzymes during pathogenesis.  Samplesinfected naturally with Chaetomium globosum and  Fusarium oxysporum exhibited higheractivity of all the enzymes compared to healthy samples &nbsp

Biochemical changes in agarwood tree (Aquilaria malaccensis Lamk.) during pathogenesis

Post-infection changes in sugars, ascorbic acid, phenols and protein of agarwood tree (Aquilaria malaccensis) were investigated after inoculation with fungi such as Chaetomium globosum and Fusarium oxysporum. In healthy trees, the biochemical constituents increased, whereas in infected trees they decreased after inoculation with fungi. &nbsp

Sperm Competition, Sperm Numbers and Sperm Quality in Muroid Rodents

Sperm competition favors increases in relative testes mass and production efficiency, and changes in sperm phenotype that result in faster swimming speeds. However, little is known about its effects on traits that contribute to determine the quality of a whole ejaculate (i.e., proportion of motile, viable, morphologically normal and acrosome intact sperm) and that are key determinants of fertilization success. Two competing hypotheses lead to alternative predictions: (a) sperm quantity and quality traits co-evolve under sperm competition because they play complementary roles in determining ejaculate's competitive ability, or (b) energetic constraints force trade-offs between traits depending on their relevance in providing a competitive advantage. We examined relationships between sperm competition levels, sperm quantity, and traits that determine ejaculate quality, in a comparative study of 18 rodent species using phylogenetically controlled analyses. Total sperm numbers were positively correlated to proportions of normal sperm, acrosome integrity and motile sperm; the latter three were also significantly related among themselves, suggesting no trade-offs between traits. In addition, testes mass corrected for body mass (i.e., relative testes mass), showed a strong association with sperm numbers, and positive significant associations with all sperm traits that determine ejaculate quality with the exception of live sperm. An “overall sperm quality” parameter obtained by principal component analysis (which explained 85% of the variance) was more strongly associated with relative testes mass than any individual quality trait. Overall sperm quality was as strongly associated with relative testes mass as sperm numbers. Thus, sperm quality traits improve under sperm competition in an integrated manner suggesting that a combination of all traits is what makes ejaculates more competitive. In evolutionary terms this implies that a complex network of genetic and developmental pathways underlying processes of sperm formation, maturation, transport in the female reproductive tract, and preparation for fertilization must all evolve in concert

Characterization of arbuscular mycorrhizal fungus communities of Aquilaria crassna and Tectona grandis roots and soils in Thailand plantations

Aquilaria crassna Pierre ex Lec. and Tectona grandis Linn.f. are sources of resin-suffused agarwood and teak timber, respectively. This study investigated arbuscular mycorrhizal (AM) fungus community structure in roots and rhizosphere soils of A. crassna and T. grandis from plantations in Thailand to understand whether AM fungal communities present in roots and rhizosphere soils vary with host plant species and study sites. Terminal restriction fragment length polymorphism complemented with clone libraries revealed that AM fungal community composition in A. crassna and T. grandis were similar. A total of 38 distinct terminal restriction fragments (TRFs) were found, 31 of which were shared between A. crassna and T. grandis. AM fungal communities in T. grandis samples from different sites were similar, as were those in A. crassna. The estimated average minimum numbers of AM fungal taxa per sample in roots and soils of T. grandis were at least 1.89 vs. 2.55, respectively, and those of A. crassna were 2.85 vs. 2.33 respectively. The TRFs were attributed to Claroideoglomeraceae, Diversisporaceae, Gigasporaceae and Glomeraceae. The Glomeraceae were found to be common in all study sites. Specific AM taxa in roots and soils of T. grandis and A. crassna were not affected by host plant species and sample source (root vs. soil) but affected by collecting site. Future inoculum production and utilization efforts can be directed toward the identified symbiotic associates of these valuable tree species to enhance reforestation efforts

Ethno-medico-botany of the <i style="">Dimasa Kachari</i> of North Cachar Hills district of Assam

718-720Folklore medicinal uses of 25 plant species belonging to 23 families for various ailments among the Dimasa Kacharis, one of the prominent ethnic tribes of North Kachar Hills district of Assam is reported. The study was undertaken covering the area of Dimasa inhabiting villages of NC Hills district of Assam

<b>Ethno-medico-botany of the Zeme tribe of North Cachar Hills district of Assam</b>

430-436 Folklore medicinal uses of 33 plant species belonging to 22 families for various ailments among the Zeme Nagas, one of the prominent ethnic tribes of North Cachar Hills district of Assam, India is reported. The study was undertaken during1999-2000 covering the area of Zeme inhabiting villages of N. C. Hills district of Assam. </smarttagtype

Dominant Suppression of Repeat-Induced Point Mutation in Neurospora crassa by a Variant Catalytic Subunit of DNA Polymerase-ζ

Crosses involving the Adiopodoumé strain of Neurospora crassa are defective for repeat-induced point mutation (RIP), a genome defense mechanism of fungi. We show here that the Adiopodoumé strain possesses an incompletely penetrant and variably expressive dominant suppressor of RIP (Srp) that maps to an ∼34-kbp genome segment that is ∼26 kbp proximal to mat on linkage group IL. Gene disruption experiments revealed that Srp is the upr-1 allele of Adiopodoumé (upr-1Ad) that is contained within this segment. The upr-1 gene codes for the catalytic subunit of the translesion DNA polymerase-ζ (Pol-ζ) and it is unusually polymorphic in Neurospora. That the upr-1 gene contains upstream ORFs that overlap with the main ORF is potentially relevant to the incomplete penetrance and variable expressivity of the suppressor. Crosses between heterokaryons that contain upr-1Ad and strains that prevent mating events involving nuclei that contain upr-1Ad yielded no progeny in which RIP had occurred, consistent with the idea that the suppressor encoded by upr-1Ad is diffusible. The potential involvement of the Pol-ζ subunit in two functions, translesion DNA synthesis and RIP regulation, might account for the rapid evolution of its gene in Neurospora

Genetic transformation of Neurospora tetrasperma, demonstration of repeat-induced point mutation (RIP) in self-crosses and a screen for recessive RIP-defective mutants.

The pseudohomothallic fungus Neurospora tetrasperma is naturally resistant to the antibiotic hygromycin. We discovered that mutation of its erg-3 (sterol C-14 reductase) gene confers a hygromycin-sensitive phenotype that can be used to select transformants on hygromycin medium by complementation with the N. crassa erg-3+ and bacterial hph genes. Cotransformation of hph with PCR-amplified DNA of other genes enabled us to construct strains duplicated for the amplified DNA. Using transformation we constructed self-fertile strains that were homoallelic for an ectopic erg-3+ transgene and a mutant erg-3 allele at the endogenous locus. Self-crosses of these strains yielded erg-3 mutant ascospores that produced colonies with the characteristic morphology on Vogel's sorbose agar described previously for erg-3 mutants of N. crassa. The mutants were generated by repeat-induced point mutation (RIP), a genome defense process that causes numerous G:C to A:T mutations in duplicated DNA sequences. Homozygosity for novel recessive RIP-deficient mutations was signaled by self-crosses of erg-3-duplication strains that fail to produce erg-3 mutant progeny. Using this assay we isolated a UV-induced mutant with a putative partial RIP defect. RIP-induced mutants were isolated in rid-1 and sad-1, which are essential genes, respectively, for RIP and another genome defense mechanism called meiotic silencing by unpaired DNA