Colletotrichum fructicola, a Member of Colletotrichum gloeosporioides sensu lato, is the Causal Agent of Anthracnose and Soft Rot in Avocado Fruits cv. “Hass”

The filamentous Ascomycota Colletotrichum gloeosporioides sensu lato is a fungus that has been reported worldwide as a causal agent of anthracnose disease in avocado and other crops. In Mexico, this species affects fruits from an early stage of development in the orchard until the post-harvest stage. Although fungicides are continuously applied to control Colletotrichum species, pericarp cankers and soft rot mesocarp in fruits are still frequently observed. Considering the lack of a precise description of the causative agent, the aim of the current study was to determine the pathogens involved in this symptomatology. Twenty-four isolates were consistently obtained from the pericarp of avocado fruits cv. “Hass” collected in the central avocado-producing area of Mexico. Morphological features such as colony growth, conidia size, and mycelial appressorium were assessed. Bayesian multilocus phylogenetic analyses were performed using amplified sequences of the internal transcribed spacer region of the nuclear ribosomal DNA; actin, chitin synthase, glyceraldehyde-3-phosphate dehydrogenase partial genes; and APn2-Mat1-2 intergenic spacer and mating type Mat1-2 partial gene from the nine selected isolates. In addition, fruits were inoculated with a conidial suspension and reproducible symptoms confirmed the presence of Colletotrichum fructicola in this area. This pathogenic species can now be added to those previously reported in the country, such as C. acutatum, C. boninense, C. godetiae, C. gloeosporioides, and C. karstii. Disease management programs to reduce the incidence of anthracnose should include C. fructicola to determine its response to fungicides that are routinely applied, considering that the appearance of new species is affecting the commercial quality of the fruits and shifting the original population structure.

First Report of Two Colletotrichum Species Associated with Bitter Rot on Apple Fruit in Korea – C. fructicola and C. siamense

Bitter rot caused by the fungal genus Colletotrichum is a well-known, common disease of apple and causes significant yield loss. In 2013, six fungal strains were isolated from Fuji apple fruits exhibiting symptoms of bitter rot from Andong, Korea. These strains were identified as Colletotrichum fructicola and C. siamense based on morphological characteristics and multilocus sequence analysis of the internal transcribed spacer rDNA, actin, calmodulin, chitin synthase, and glyceraldehyde-3-phosphate dehydrogenase Pathogenicity tests confirmed the involvement of C. fructicola and C. siamense in the development of disease symptoms on apple fruits. This is the first report of C. fructicola and C. siamense causing bitter rot on apple fruit in Korea.

Role of LAMMER Kinase in Cell Wall Biogenesis during Vegetative Growth of Aspergillus nidulans

Depending on the acquisition of developmental competence, the expression of genes for beta-1,3-glucan synthase and chitin synthase was affected in different ways by Aspergillus nidulans LAMMER kinase. LAMMER kinase deletion, DeltalkhA, led to decrease in beta-1,3-glucan, but increase in chitin content. The DeltalkhA strain was also resistant to nikkomycin Z.

The efficacy of a chitin synthesis inhibitor against field populations of organophosphate-resistant Aedes aegypti in Brazil

The mosquito Aedes aegypti is the main focus of dengue control campaigns. Because of widespread resistance against conventional chemical insecticides, chitin synthesis inhibitors (CSIs) are considered control alternatives. We evaluated the resistance status of four Brazilian Ae. aegypti populations to both the organophosphate temephos and the pyrethroid deltamethrin, which are used in Brazil to control larvae and adults, respectively. All vector populations exhibited high levels of temephos resistance and varying rates of alterations in their susceptibility to pyrethroids. The effect of the CSI novaluron on these populations was also investigated. Novaluron was effective against all populations under laboratory conditions. Field-simulated assays with partial water replacement were conducted to evaluate novaluron persistence. Bioassays were continued until an adult emergence inhibition of at least 70% was attained. We found a residual effect of eight weeks under indoor conditions and novaluron persisted for five-six weeks in assays conducted in an external area. Our data show that novaluron is effective against the Ae. aegypti populations tested, regardless of their resistance to conventional chemical insecticides.

Clinical Experiences Treating Edifenphos and Iprobenfos Intoxication Patients

Organophosphate fungicides include edifenphos, iprobenfos and tolclofos-methyl. Edifenphos inhibits cell wall synthesis by reduction in chitin synthase activity and inhibits the action of acetylcholinesterase. Thus, exposure to this chemical results in excessive salivation, lacrimation, urination, defecation, gastrointestinal motility and emesis symptoms, just like other organophosphate insecticides. Although edifenphos is an organophosphate fungicide, it is the only agricultural chemical which inhibits the action of pralidoxime and atropine, an activity which in turn, inhibits treatment. Thus, we have to treat these cases as soon as possible with atropine and pralidoxime, using the same approach as used for exposure to other organophosphate insecticides. In this report we evaluate the results of treatment of 4 patients who were intoxicated by fungicides (3 cases with edifenphos and 1 case with iprobenfos).

Deletion of GBG1/AYR1 Alters Cell Wall Biogenesis in Saccharomyces cerevisiae

We identified a gene for beta-1,3-glucan synthesis (GBG1), a nonessential gene whose disruption alters cell wall synthesis enzyme activities and cell wall composition. This gene was cloned by functional complementation of defects in beta-1,3-glucan synthase activity of the the previously isolated Saccharomyces cerevisiae mutant LP0353, which displays a number of cell wall defects at restrictive temperature. Disruption of the GBG1 gene did not affect cell viability or growth rate, but did cause alterations in cell wall synthesis enzyme activities: reduction of beta-1,3-glucan synthase and chitin synthase III activities as well as increased chitin synthase I and II activities. GBG1 disruption also showed altered cell wall composition as well as susceptibility toward cell wall inhibitors such as Zymolyase, Calcofluor white, and Nikkomycin Z. These results indicate that GBG1 plays a role in cell wall biogenesis in S. cerevisiae

Field evaluation of novaluron, a chitin synthesis inhibitor larvicide, against mosquito larvae in polluted water in urban areas of Bangkok, Thailand.

Novaluron, an insect growth regulator, a benzoylphenyl urea insecticide, was evaluated in the field against the larvae of polluted-water mosquitoes. The study was carried out in highly polluted sites infested with populations of mosquito larvae, mostly Culex quinquefasciatus Say, in low-income communities in urban areas of Bangkok, Thailand. An EC10 formulation was premixed in water and applied by pressurized spray tank to plots ranging from 180 to 1,000 m2 at the rate of 0.1 ml EC 10/m2 (equal to 10 mg a.i./m2) of the breeding sites. Assessments were made by sampling mosquito larvae and pupae to determine the trends of immature populations before treatment and weekly after treatment. Reduction of the populations in percents were then computed by comparing counts of immature mosquitoes (larvae and pupae) to the pretreatment counts at each particular site. It was found that the immature populations of mosquitoes in the treated areas were dramatically suppressed and remained at extremely low levels for 3-7 weeks after the treatment depending on the prevailing conditions of each experimental site. No negative impact on fishes or aquatic plants in the treated areas were detected during the study period and three months after the experiment was discontinued. Novaluron is an effective agent to control immature populations of polluted-water mosquitoes, especially Cx. quinquefasciatus in habitats in urban areas. This IGR larvicide may play an important role in vector control programs in terms of effectiveness, environmental friendliness and strategies for insecticide-resistance management in vector mosquitoes.

Efeito de triflumuron- um inibidor da síntese de quitina - sobre o desenvolvimento e a reprodução de culicídeos vetores de doenças / Effect of triflumuron- an inhibitor of the synthesis of quitina - on the development and the reproduction of culicidae disease vectors

Aedes aegypti, Aedes albopictus e Culex quinquefasciatus são 3 espécies de mosquito difundidas principalmente nas regiões tropicais e subtropicais do globo. No Brasil, estão relacionadas com a transmissão de doenças como a dengue e a filariose linfática e há grande preocupação com sua potencial participação na transmissão de outras arboviroses, como o vírus do oeste do Nilo e o da febre amarela. Atualmente, a principal forma de combate a vetores de doenças é realizada através do uso de inseticidas químicos, cujo sítio de ação é o sistema nervoso central do inseto. Como conseqüência do uso maciço destes produtos, a freqüência de indivíduos resistentes em populações de várias espécies de insetos vetores tem aumentado. Os reguladores do desenvolvimento de insetos aparecem como uma nova alternativa de controle de mosquitos vetores. Neste grupo, encontram-se os inibidores da síntese de quitina (CSI), substâncias que prejudicam o processo de muda, acarretando deficiências principalmente na cutícula dos insetos. No presente trabalho, verificou-se que o CSI triflumuron foi eficaz contra estas 3 espécies de culicídeos vetores, em concentrações na ordem de (miu)g/L. Além disso, foi investigado o efeito da aplicação, em larvas, de dose parcialmente letal de triflumuron sobre vários aspectos da biologia de Ae. aegypti. De modo geral, a longevidade, aceitação do repasto sangüíneo, volume de sangue ingerido, reprodução e postura são afetados negativamente nos adultos sobreviventes ao tratamento na fase imatura. Triflumuron foi eficaz contra diversas populações de campo de Ae. aegypti, com diferentes níveis de susceptibilidade ao organofosforado temephos e ao piretróide deltametrina: não houve emergência de adultos viáveis quando as larvas foram expostas à IE99 de triflumuron para a cepa-referência Rockefeller. Embora não tenha sido detectada resistência cruzada entre aqueles inseticidas químicos e o CSI, a mortalidade de populações resistentes ao temephos, mas não à deltam...

The Mycological and Molecular Biological Studies on Arthroderma benhamiae Isolated for the First Time in Korea / 대한의진균학회지

BACKGROUND: Arthroderma (A.) benhamiae, one of three telemorphs of Trichophyton (T.) mentagrophytes, has not been isolated until recently in Korea, but in Japan the first report on it was made in 1998. OBJECTIVE: To identify A. benhamiae for the first time in Korea. METHODS: Twelve strains suggestive of A. benhamiae grossly and microscopically were detected among 1, 059 of T. mentagrophytes isolated at the Catholic Skin Clinic, Daegu, from 1998 to 2000. They were examined by mating tests and molecular methods. In mating tests, they were respectively crossed with "+" and "-" tester strains of A. vanbreuseghemii, A. benhamiae African race, A. benhamiae Americano-European race. Molecular methods included the sequence analysis of internal transcribed spacer 2 (ITS2) region of ribosomal DNA and chitin synthase 1 (CHS1) gene, and random amplified DNA polymorphism (RAPD) with random primer OPAO-15 (5'-GAA GGC TCC C-3'). RESULTS: Mating tests revealed that 12 strains of T. mentagrophytes consisted of 6 of A. benhamiae, 4 of A. vanbreuseghemii and 2 of indeterminate. Six strains of A. benhamiae, all isolated from the patients with a history of contact with rabbits, included 1 of Americano-European race and 5 of African race of Americano-European race and 5 of African race. One clinical isolate, a strain of A. benhamiae Americano-European race "-" in mating tests, was almost identical with the standard strains of A. benhamiae Americano-European race with molecular methods as 99.2% (351/354) similarity of ITS2 sequence, 99.1% (313/ 316) similarity of CHS1 sequence, and similar RAPD pattern. Five clinical strains of A. benhamiae African race were identical with standard strains in ITS2 and CHS1 gene and RAPD pattern. CONCLUSION: The first isolation of 6 strains of A. benhamiae in Korea was reported. Five were identified as A. benhamiae African race "+", and 1 as A. benhamiae Americano-European race "-".

The Mycological and Molecular Biological Studies on Arthroderma benhamiae Isolated for the First Time in Korea / 대한의진균학회지

BACKGROUND: Arthroderma (A.) benhamiae, one of three telemorphs of Trichophyton (T.) mentagrophytes, has not been isolated until recently in Korea, but in Japan the first report on it was made in 1998. OBJECTIVE: To identify A. benhamiae for the first time in Korea. METHODS: Twelve strains suggestive of A. benhamiae grossly and microscopically were detected among 1, 059 of T. mentagrophytes isolated at the Catholic Skin Clinic, Daegu, from 1998 to 2000. They were examined by mating tests and molecular methods. In mating tests, they were respectively crossed with "+" and "-" tester strains of A. vanbreuseghemii, A. benhamiae African race, A. benhamiae Americano-European race. Molecular methods included the sequence analysis of internal transcribed spacer 2 (ITS2) region of ribosomal DNA and chitin synthase 1 (CHS1) gene, and random amplified DNA polymorphism (RAPD) with random primer OPAO-15 (5'-GAA GGC TCC C-3'). RESULTS: Mating tests revealed that 12 strains of T. mentagrophytes consisted of 6 of A. benhamiae, 4 of A. vanbreuseghemii and 2 of indeterminate. Six strains of A. benhamiae, all isolated from the patients with a history of contact with rabbits, included 1 of Americano-European race and 5 of African race of Americano-European race and 5 of African race. One clinical isolate, a strain of A. benhamiae Americano-European race "-" in mating tests, was almost identical with the standard strains of A. benhamiae Americano-European race with molecular methods as 99.2% (351/354) similarity of ITS2 sequence, 99.1% (313/ 316) similarity of CHS1 sequence, and similar RAPD pattern. Five clinical strains of A. benhamiae African race were identical with standard strains in ITS2 and CHS1 gene and RAPD pattern. CONCLUSION: The first isolation of 6 strains of A. benhamiae in Korea was reported. Five were identified as A. benhamiae African race "+", and 1 as A. benhamiae Americano-European race "-".

Control of ctenocephalides felis on dogs and cats using the insect growth regulator [or chitin synthesis inhibitor] lufenuron program, in Egypt

Lufenuron, the chitin synthesis inhibitor [Program, Novartis, Switzerland] was given orally at doses of 10 mg/kg b. wt. to dogs and 30 mg/kg b. wt. to cats every four weeks [monthly] for the treatment of experimental flea infestations. Three-four weeks after the last infestation, lufenuron had effectively controlled the Ct. Felis infestation of dogs and cats as the drug prevented the development of the offspring of adult female fleas feeding on animals. Flea populations remained absent or very low until the end of the study, 91 days after the first treatment

Cloning and Phylogenetic Analysis of Chitin Synthase Genes from Tricholoma matsutake

Chitin synthases(UDP-N-acetyl-D-glucosamine: chitin 4-beta-N-acetyl-D-glucosaminyl transferase, EC 2.4.1.16) catalyze the synthesis of chitin from UDP-N-acetyl-D-glucosamine. Two zymogenic type of chitin synthase gene(TmCHS1 and TmCHS2) were amplified and its nucleotide sequences were determined. By the amino acid comparison and UPGMA tree grouping, TmChs1 and TmChs2 were classified as class II and class IV chitin synthases respectively. The class II type TmChs1 was grouped with others of Agaricales ectomycorrhizal mushroom. Additionally the phylogenetic tree was well adapted to Hymenomycete previously classified by morphological and physiological characteristics.

Phylogeny and Taxonomy of the Dermatophytes Using Sequence Analysis of the Chitin Synthase 1 Gene / 대한의진균학회지

BACKGROUND: The species of dermatophytes have been identified and classified by morphological and biochemical characterization as well as by mating experiments. But these techniques are either time consuming or lacking specificity. Recently molecular analysis has been introduced to the field of medical mycology. OBJECTIVE: We investigated the phylogeny and taxomomy of the dermatophytes using sequence analysis of the chitin synthase 1 (CHS1) gene. METHODS: 15 species of dermatophytes (6 strains of T.rubrum, 4 strains of T. mentagrophytes subtypes, M. canis, M. gypseum, E. floccosum, T. verrucosum, and T. tonsurans) were cultured on Sabouraud dextrose broth and their DNA were extracted by bead-beating method. Cloning and sequencing of PCR product were done. RESULTS: The size of specific bands among dermatophytes was 615 bp in CHS1 gene. Phylogenetic analysis of sequences revealed that 6 strains of T. rubrum showed genetically identical pattern in intraspecies, but subtypes of T. mentagrophytes were different. The other dermatophytes showed different pattern in interspecies. CONCLUSION: The phylogenetic analysis of CHS1 gene provided useful information for classification and understanding the evolution of dermatophytes species.

Flow cytometry analysis of cell cycle in myosin II-deficient yeast

OBJECTIVE: To determine whether cell cycle changes can be detected in myosin II-deficient cells using flow cytometry techniques. BACKGROUND: Although the primary role of myosin II (Myo1p) in the yeast Saccharomyces cerevisiae is in cytokinesis we have reported that this conventional myosin also appears to inuence the regulation of cell wall metabolism as indicated by increases in the expression of chitin metabolizing enzymes in a null mutant of the MYO1 gene. The expression of these enzymes is known to be regulated in the cell cycle suggesting that cell cycle changes may alter their expression. METHODS: Flow cytometry was employed to assess the nuclear DNA content of logarithmic yeast cell cultures as a means of determining changes in the cell cycle of Myo1p-deficient cells. RESULTS: Significant changes were observed in the Myo1p-deficient strain suggesting that these cells are arrested in G2/M-phase of the cell cycle. CONCLUSIONS: Based on the results of this preliminary study, we propose a model in which the increased activity of chitin metabolizing enzymes may be explained by a mitotic arrest in these cells.

Fotoactivación in vitro de la quitina sintetasa de los esporangioforos de Phycomyces blakesleeanus / In vitro photoactivation of chitin synthetase from Phycomyces blakesleeanus sporangiophores

Se estudió el mecanismo de la foto-activación de la quitina sintetasa presente en los esporangióforos de Phycomyces en estado IV. La enzima se estabilizó parcialmente cuando los extractos se obtuvieron en presencia de sacarosa; se obtuvo la máxima actividad a pH 7.8 y se estimuló por adición de proteasas exógenas. La iluminación de los extractos con luz blanca produjo una estimulación promdeido en la actividad del 75% en ausencia de tripsina y del 21% en presencia de la proteasa. En la obscuridad, la adición de Ca 2+ produjo una débil estimulación a bajas concentraciones y una inhibición a concentraciones mas altas; su adicion dio lugar a una alta activación por la luz. La iodo-acetamida inhibio la activación de la quitina sintetasa por la luz y por la tripsina. Con estos resultados se propone un modelo para explicar el mecanismo de activación de la quitina sintetasa por la luz