Involvement of Indole-3-Acetic Acid Metabolism in the Early Fruit Development of the Parthenocarpic Tomato Cultivar,MPK-1

Journal of Plant Growth Regulation - Parthenocarpy, or fruit set and growth without fertilization, is a desirable trait in tomato cultivation as it reduces the cost of tomato production. MPK-1 is a...     

PCR-based Specific Detection of Ustilaginoidea virens and Ephelis japonica

A PCR‐based technique for detection of clavicipitaceous pathogens in rice and related grasses was developed. The target pathogens were Ustilaginoidea virens, which causes rice false smut, and Ephelis japonica, which causes rice udbatta disease and black choke in grasses. To design specific primers, a comparison was made on genetic diversity on the rDNA internal transcribed spacers (ITS1 and ITS2) and the 5.8S rRNA gene of U. virens, Ephelis japonica, as well as some other clavicipitaceous fungi. Each fungus was successfully detected by using a specific primer set with high sensitivity. Species‐specific primers designed here were capable of detecting these pathogens in plant tissues. The PCR detection was consistent with conventional histological observation. This nested PCR assay was sensitive and reliable for the detection of U. virens and E. japonica, and thus can be a used to study disease cycles and early prediction of false smut and udbatta‐disease incidence in fields.     

Diverse effects of hydrogen peroxide on cytosolic Ca2+ homeostasis in rat pancreatic beta-cells

Oxygen-free radicals are thought to be a major cause of beta-cell dysfunction in diabetic animals induced by alloxan or streptozotocin. We evaluated the effect of H2O2 on cytosolic Ca2+ concentration ([Ca2+]i) and the activity of ATP-sensitive potassium (K+ATP) channels in isolated rat pancreatic beta-cells using microfluorometry and patch clamp techniques. Exposure to 0.1 mM H2O2 in the presence of 2.8 mM glucose increased [Ca2+]i from 114.3+/-15.4 nM to 531.1+/-71.9 nM (n=6) and also increased frequency of K+ATP channel openings. The intensity of NAD(P)H autofluorescence was conversely reduced, suggesting that H2O2 inhibited the cellular metabolism. These three types of cellular parameters were reversed to the control level on washout of H2O2, followed by a transient increase in [Ca2+]i, the transient inhibition of K+ATP channels associated with action currents and increase of the NAD(P)H intensity with an overshoot. In the absence of external Ca2+, 0.1 mM H2O2 increased [Ca2+]i from 88.8+/-7.2 nM to 134.6+/-8.3 nM. Magnitude of [Ca2+]i increase induced by 0.1 mM H2O2 was decreased after treatment of cells with 0.5 mM thapsigargin, an inhibitor of endoplasmic reticulum Ca2+ pump (45.8+/-4.9 nM vs 15.0+/-4.8 nM). Small increase in [Ca2+]i in response to an increase of external Ca2+ from zero to 2 mM was further facilitated by 0.1 mM H2O2 (330.5+/-122.7 nM). We concluded that H2O2 not only activates K+ATP channels in association with metabolic inhibition, but also increases partly the Ca2+ permeability of the thapsigargin-sensitive intracellular stores and of the plasma membrane in pancreatic beta-cells.     

Genetic disease patterns in Japan: a review.

Comprehensive genetic studies in which the genetic structure of a population is considered against the background of ecological factors, including environmental and social variables, often supply valuable information for the solution of a number of problems in human biology, including reproductive compensation and inbreeding depression. In the first section of this paper we consider the incidence of genetic diseases in Japan in reference to other populations. Some of the genetic disorders found elsewhere do not occur or are of lower frequencies in Japan. On the other hand, a number of genetic diseases occur at higher than usual frequencies, leading to an incidence of genetic disease of the order of about 1 per 100 in newborn Japanese. We next review the studies of consanguinity in Japan and report evidence of very high levels, ranging from 8.6% to 58.0%, for villages during the early part of the twentieth century. The rates are declining rapidly for the country but, because of traditional social values, inbreeding rates remain significant in many small villages. In the final section we consider the probable trends in the frequency of inbreeding on a worldwide basis and point out that frequencies of certain genetic diseases are likely to remain high and even increase in some societies because of various socially prescribed mating patterns.     

Complete Genomic Structure of the Bloom-forming Toxic Cyanobacterium Microcystis aeruginosa NIES-843

The nucleotide sequence of the complete genome of a cyanobacterium,Microcystis aeruginosa NIES-843, was determined. The genomeof M. aeruginosa is a single, circular chromosome of 5 842 795base pairs (bp) in length, with an average GC content of 42.3%.The chromosome comprises 6312 putative protein-encoding genes,two sets of rRNA genes, 42 tRNA genes representing 41 tRNA species,and genes for tmRNA, the B subunit of RNase P, SRP RNA, and6Sa RNA. Forty-five percent of the putative protein-encodingsequences showed sequence similarity to genes of known function,32% were similar to hypothetical genes, and the remaining 23%had no apparent similarity to reported genes. A total of 688kb of the genome, equivalent to 11.8% of the entire genome,were composed of both insertion sequences and miniature inverted-repeattransposable elements. This is indicative of a plasticity ofthe M. aeruginosa genome, through a mechanism that involveshomologous recombination mediated by repetitive DNA elements.In addition to known gene clusters related to the synthesisof microcystin and cyanopeptolin, novel gene clusters that maybe involved in the synthesis and modification of toxic smallpolypeptides were identified. Compared with other cyanobacteria,a relatively small number of genes for two component systemsand a large number of genes for restriction-modification systemswere notable characteristics of the M. aeruginosa genome.     

Aldehyde Dehydrogenase 3B1 (ALDH3B1): Immunohistochemical Tissue Distribution and Cellular-specific Localization in Normal and Cancerous Human Tissues

Aldehyde dehydrogenase (ALDH) enzymes are critical in the detoxification of endogenous and exogenous aldehydes. Our previous findings indicate that the ALDH3B1 enzyme is expressed in several mouse tissues and is catalytically active toward aldehydes derived from lipid peroxidation, suggesting a potential role against oxidative stress. The aim of this study was to elucidate by immunohistochemistry the tissue, cellular, and subcellular distribution of ALDH3B1 in normal human tissues and in tumors of human lung, colon, breast, and ovary. Our results indicate that ALDH3B1 is expressed in a tissue-specific manner and in a limited number of cell types, including hepatocytes, proximal convoluted tubule cells, cerebellar astrocytes, bronchiole ciliated cells, testis efferent ductule ciliated cells, and histiocytes. ALDH3B1 expression was upregulated in a high percentage of human tumors (lung > breast = ovarian > colon). Increased ALDH3B1 expression in tumor cells may confer a growth advantage or be the result of an induction mechanism mediated by increased oxidative stress. Subcellular localization of ALDH3B1 was predominantly cytosolic in tissues, with the exception of normal human lung and testis, in which localization appeared membrane-bound or membrane-associated. The specificity of ALDH3B1 distribution may prove to be directly related to the functional role of this enzyme in human tissues. (J Histochem Cytochem 58:765–783, 2010)