Endemic malaria still exists in the Republic of Vanuatu, an 80-island archipelago that sits astride the southeast margin of the Southeast Asian-Melanesian malaria band (Buxton Line 170 degrees E, 20 degrees S). The annual parasite incidence has decreased dramatically over the past decade, which has been attributed to an intensive insecticide-treated bednet distribution program and implementation of a revised Plasmodium falciparum treatment policy that employs combination chloroquine + sulfadoxinelpyrimethamine as a first-line therapy. Standard malariometric surveys were conducted at 10 locations in 2 provinces, screening 2351 adults and children towards the end of the peak transmission season. Spleen rates were consistent with mesoendemic malaria. Examination of blood slides revealed a mean slide-positive rate of 22% (range 4% to 33%). P. falciparum predominated, accounting for 73% of infections, followed by P. vivax (25%). Among 396 individuals with P. falciparum, the gametocyte rate was 54%, with 37% presenting gametocytes alone without asexual stages. Only 8% and 4% of persons with asexual stage P. falciparum and P. vivax parasitaemia, respectively, were symptomatic. These data suggest that malaria transmission has increased in some locations in Vanuatu over the past decade and this report underscores the importance of appropriate bednet use and vector control in this setting as well as the impact of adding sulfadoxine/pyrimethamine and removing primaquine from the national malaria treatment formulary.
Malaria ; upper case pea ; Vanuatu ; control ; asexual

The effect of four sub-lethal concentrations (400, 800, 1,200 and 1,600 microg/ml) of three amino acids such as isoluecine, aspartic acid and phenylalanine on vegetative growth and sexual and asexual reproduction of Achlya racemosa, A. proliferoides and Saprolegnia furcata was investigated. The density of vegetative growth and diameters of vegetative colonies of species of the Oomycetes fungi decreased with rising the concentration of the applied amino acid. Vegetative hyphae of treated fungi almost appeared branched in case of S. furcata, thick in case of A. racemosa and distorted in case of A. proliferoides as compared with control. The different treatments with amino acids depressed both sporangial formation and discharge, which were dependent on the tested species of zoosporic fungi, the amino acid and its dosage. Phenylalanine was the most effective amino acid in inhibiting sporulation and S. furcata was the most sensitive fungal species. Aspartic acid and isoleucine stimulated germination of discharged spores through the formation of germlings. Gemmae formation by the three fungi was reduced at the low concentrations of amino acids and nearly missed at high concentrations. Sex organs (oogonia and antheridia) were affected partly; rudiment oogonia were observed at low concentrations (400 and 800 microg/ml) and disappeared at higher concentrations, whereas antheridial branch formation was stimulated as the fungi were treated with isoleucine and to some extent phenylalanine.
Achlya* ; Amino Acids* ; Aspartic Acid ; Fungi ; Germination ; Hyphae ; Isoleucine ; Oogonia ; Oomycetes ; Phenylalanine ; Reproduction, Asexual ; Saprolegnia* ; Spores

Chestnut blight disease caused by Cryphonectria parasitica is widely distributed throughout chestnut tree plantations in Korea. We surveyed 65 sites located at 9 provinces in South Korea, and isolated 248 virulent and 3 hypovirulent strains of chestnut blight fungus. Hypovirulent strains had dsRNA virus in the cytoplasm, which is one of the typical characteristics of hypovirulent strains. In addition, they showed more characteristics of hypovirulent strains, i.e., suppressed conidiation, reduced pigmentation in colony color, and reduced phenol oxidase activity as well as reduced pathogenicity. Hypovirulent strains, KCPH-22, KCPH-135 and KCPH-136, had a genomic dsRNA band with the molecular weight of 12.7 kb, which is the L-dsRNA of CHV1. They also had a 2.7 kb defective dsRNA band. Single conidia isolated from hypovirulent strains were cultured and various phenotypes and absence of dsRNA bands were obtained from single conidial cultures, which means that hypovirulence transmission is unstable in asexual reproduction and variations in viral heredity by asexual reproduction. Biocontrol trial using hypovirulent strains was also carried out in the chestnut tree plantations, and canker expansion in the treated trees was stopped and healed by callus formation at the margin of the canker. These results show the potentials in successful biocontrol of chestnut blight if the vegetatively compatible hypovirulent strains could be directly used around the canker formed by compatible virulent strains.
Bony Callus ; Cytoplasm ; Fungi* ; Heredity ; Korea* ; Molecular Weight ; Monophenol Monooxygenase ; Phenotype ; Pigmentation ; Reproduction, Asexual ; Spores, Fungal ; Trees ; Virulence

The rice blast fungus, Magnaporthe oryzae, is an important pathogen of rice plants. It is well known that genes encoded in the genome have different evolutionary histories that are related to their functions. Phylostratigraphy is a method that correlates the evolutionary origin of genes with evolutionary transitions. Here we applied phylostratigraphy to partition total gene content of M. oryzae into distinct classes (phylostrata), which we designated PS1 to PS7, based on estimation of their emergence time. Genes in individual phylostrata did not show significant biases in their global distribution among seven chromosomes, but at the local level, clustering of genes belonging to the same phylostratum was observed. Our phylostrata-wide analysis of genes revealed that genes in the same phylostratum tend to be similar in many physical and functional characteristics such as gene length and structure, GC contents, codon adaptation index, and level of transcription, which correlates with biological functions in evolutionary context. We also found that a significant proportion of genes in the genome are orphans, for which no orthologs can be detected in the database. Among them, we narrowed down to seven orphan genes having transcriptional and translational evidences, and showed that one of them is implicated in asexual reproduction and virulence, suggesting ongoing evolution in this fungus through lineage-specific genes. Our results provide genomic basis for linking functions of pathogenicity factors and gene emergence time.
Base Composition ; Bias (Epidemiology) ; Child ; Child, Orphaned ; Codon ; Fungi* ; Genome ; Humans ; Magnaporthe ; Methods ; Oryza ; Reproduction, Asexual ; Virulence ; Virulence Factors

The effect of blue light (BL) on the morphological development of Aspergillus niger was studied by the scanning electron microscopy (SEM) observation. Comparing with the darkness, BL was able to stimulate development of sporangiophore and conidiosphore, promote grownth of mycelium. Suppression subtractive hybridization (SSH) was conducted with tester cDNA which was from 39 to approximately 40h-old mycelium cultured under darkness and driver cDNA which was from mycelium illuminated for 3 to approximately 4h under BL after dark growth. Some cDNA bands were obtained by suppression PCR (polymerase chain reaction) with the subtractive cDNA. Positive bacterial clones were randomly picked and identified by colony PCR method. Through sequence alignments from GenBank, most of differential cDNA fragments were highly identical with some redox enzymes existing in mitochondria, and the quantitative measurement of these differential mRNA by real time RT-PCR indicated that relative expression of the identified gene fragments under BL induction was higher than that under darkness. Furthermore, the result suggested that some respiratory chain redox enzymes of mitochondria were involved in the photoresponse and consequently influence the metabolism. Among differential cDNA fragments two unkown sequences were found and their complete gene and gene function remained to be investigated.
Aspergillus niger ; genetics ; radiation effects ; ultrastructure ; DNA, Complementary ; genetics ; DNA, Plant ; genetics ; Gene Expression Profiling ; Gene Expression Regulation, Plant ; radiation effects ; Gene Library ; Light ; Microscopy, Electron, Scanning ; Nucleic Acid Hybridization ; Reproduction, Asexual ; radiation effects ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction