ABSTRACT
AIMS: The effect of nutritional supplementation of two Metarhizium species with riboflavin (Rb) during production of conidia was evaluated on (i) conidial tolerance (based on germination) to UV-B radiation and on (ii) conidial expression following UV-B irradiation, of enzymes known to be active in photoreactivation, viz., photolyase (Phr), laccase (Lac) and polyketide synthase (Pks). METHODS AND RESULTS: Metarhizium acridum (ARSEF 324) and Metarhizium robertsii (ARSEF 2575) were grown either on (i) potato dextrose agar medium (PDA), (ii) PDA supplemented with 1% yeast extract (PDAY), (iii) PDA supplemented with Rb (PDA+Rb), or (iv) PDAY supplemented with Rb (PDAY+Rb). Resulting conidia were exposed to 866·7 mW m-2 of UV-B Quaite-weighted irradiance to total doses of 3·9 or 6·24 kJ m-2 . Some conidia also were exposed to 16 klux of white light (WL) after being irradiated, or not, with UV-B to investigate the role of possible photoreactivation. Relative germination of conidia produced on PDA+Rb (regardless Rb concentration) or on PDAY and exposed to UV-B was higher compared to conidia cultivated on PDA without Rb supplement, or to conidia suspended in Rb solution immediately prior to UV-B exposure. The expression of MaLac3 and MaPks2 for M. acridum, as well as MrPhr2, MrLac1, MrLac2 and MrLac3 for M. robertsii was higher when the isolates were cultivated on PDA+Rb and exposed to UV-B followed by exposure to WL, or exposed to WL only. CONCLUSIONS: Rb in culture medium increases the UV-B tolerance of M. robertsii and M. acridum conidia, and which may be related to increased expression of Phr, Lac and Pks genes in these conidia. SIGNIFICANCE AND IMPACT OF THE STUDY: The enhanced UV-B tolerance of Metarhizium spp. conidia produced on Rb-enriched media may improve the effectiveness of these fungi in biological control programs.
Subject(s)
Metarhizium , Riboflavin/pharmacology , Spores, Fungal , Up-Regulation/drug effects , Deoxyribodipyrimidine Photo-Lyase/genetics , Deoxyribodipyrimidine Photo-Lyase/metabolism , Laccase/genetics , Laccase/metabolism , Metarhizium/drug effects , Metarhizium/enzymology , Metarhizium/genetics , Metarhizium/radiation effects , Polyketide Synthases/genetics , Polyketide Synthases/metabolism , Spores, Fungal/drug effects , Spores, Fungal/radiation effects , Ultraviolet RaysABSTRACT
AIMS: The genetic diversity of Beauveria bassiana was investigated by comparing isolates of this species to each other (49 from different geographical regions of Brazil and 4 from USA) and to other Beauveria spp. METHODS AND RESULTS: The isolates were examined by multilocus enzyme electrophoresis (MLEE), amplified fragment length polymorphism (AFLP), and rDNA sequencing. MLEE and AFLP revealed considerable genetic variability among B. bassiana isolates. Several isolates from South and Southeast Brazil had high similarity coefficients, providing evidence of at least one population with clonal structure. There were clear genomic differences between most Brazilian and USA B. bassiana isolates. A Mantel test using data generated by AFLP provided evidence that greater geographical distances were associated with higher genetic distances. AFLP and rDNA sequencing demonstrated notable genotypic variation between B. bassiana and other Beauveria spp. CONCLUSION: Geographical distance between populations apparently is an important factor influencing genotypic variability among B. bassiana populations in Brazil. SIGNIFICANCE AND IMPACT OF THE STUDY: This study characterized many B. bassiana isolates. The results indicate that certain Brazilian isolates are considerably different from others and possibly should be regarded as separate species from B. bassiana sensu latu. The information on genetic variation among the Brazilian isolates, therefore, will be important to comprehending the population structure of B. bassiana in Brazil.
Subject(s)
Hypocreales/genetics , Amplified Fragment Length Polymorphism Analysis , Brazil , DNA, Fungal/genetics , DNA, Ribosomal/genetics , Electrophoresis/methods , Genetic Variation , Genotype , Geography , Hypocreales/enzymology , Sequence Analysis, DNA , United StatesABSTRACT
A light microscopy study of head cartilage tissue in rainbow trout alevins (Oncorhynchus mykiss) infected with the parasite Myxobolus cerebralis showed that, regardless of the presence or absence of whirling disease symptoms such as black tail and whirling swimming due to altered tail and spine morphology, some fish presented large amounts of spores lodged in the head after three months of infection. The spores were located in regions where the cartilage was extensively destroyed.
Subject(s)
Cartilage Diseases/veterinary , Cartilage/parasitology , Eukaryota/physiology , Fish Diseases/parasitology , Oncorhynchus mykiss/parasitology , Protozoan Infections, Animal/parasitology , Animals , Behavior, Animal , Cartilage/pathology , Cartilage Diseases/parasitology , Cartilage Diseases/pathology , Cartilage Diseases/physiopathology , Eukaryota/cytology , Eukaryota/isolation & purification , Fish Diseases/pathology , Fish Diseases/physiopathology , Protozoan Infections, Animal/pathology , Protozoan Infections, Animal/physiopathology , Skull , SwimmingABSTRACT
A light, transmission and scanning microscope study of the rays (lepidotrichia) forming the tail fin of rainbow trout (Oncorhynchus mykiss) fingerlings infected with the parasite Myxobolus cerebralis showed that triactinomyxon adherence to the tail fin of host fingerlings occurred 10 min after infection. After 2 h of exposure, it was possible to observe triactinomyxon spores in the epidermis. Although the characteristic symptoms of the disease, such as a black tail and a change in tail morphology, were observed, there was no attack against the tissue forming the tail fin rays and triactinomyxon spores were not observed inside the leptotrichial matrix at any stage, indicating that the spores do not reach the rays or that their observation was not possible under the conditions of the present study.
Subject(s)
Eukaryota/physiology , Fish Diseases/parasitology , Oncorhynchus mykiss/parasitology , Protozoan Infections, Animal/parasitology , Spine/ultrastructure , Tail/ultrastructure , Animals , Behavior, Animal , Bone and Bones , Eukaryota/pathogenicity , Eukaryota/ultrastructure , Fish Diseases/pathology , Fish Diseases/physiopathology , Host-Parasite Interactions , Microscopy, Electron, Scanning/veterinary , Protozoan Infections, Animal/pathology , Protozoan Infections, Animal/physiopathology , SwimmingABSTRACT
The germination processes of ARS-1590, ARS-1261 and ARS-1229 isolates of Zoophthora radicans (Brefeld) Batko on fifth-instar Empoasca kraemeri (Ross & Moore, 1957) nymphs, at 20ºC and 100% relative humidity were investigated and compared. The primary conidia on the insect germinated within two hours after inoculation for all isolates. The total production of germ tubes tended to be equal to that of capilliconidium on the host body, 12 hours after inoculation. The secondary conidia proportion, among the forms produced by the primary conidia on the insect, did not exceed 25% in all body regions.
Foram analisados e comparados os processos de germinação dos isolados ARS-1590, ARS-1261 e ARS-1229 de Zoophthora radicans (Brefeld) Batko sobre ninfas do 5º ínstar de Empoasca kraemeri (Ross & Moore, 1957) a 20ºC e 100% de umidade relativa (RH). A germinação dos conídios primários dos isolados sobre o inseto iniciou-se dentro do período de duas horas após a inoculação. A produção total de tubos germinativos tendeu a se igualar a de capiloconídios sobre o corpo do hospedeiro, doze horas após a inoculação. A proporção de conídios secundários, dentro das formas geradas pelos conídios primários germinados sobre o inseto, não ultrapassou 25% em qualquer das regiões do corpo.
ABSTRACT
The penetration ability of ARS-1590, ARS-1261 and ARS-1229 isolates of Zoophthora radicans (Brefeld) Batko on fifth-instar Empoasca kraemeri (Hoss & Moore) nymphs, at 20°C and 100% relative humidity (RH), were investigated and compared. The apressorium formation and isolates penetration began within the six hours after inoculation. The penetration occured in greater proportion in the abdome, followed by the thorax and head, more often through membranes than sclerites.
Foram analisados e comparados os processos de germinação e habilidade de infecção dos isolados ARS-1590, ARS-1261 e ARS-1229 de Zoophthora radicans (Brefeld) Batko sobre ninfas do 5º ínstar de Empoasca kraemeri (Hoss & Moore) em ambiente de 20°C e 100% de umidade relativa. A formação de apressório e penetração dos isolados iniciaram-se dentro do período de seis horas após a inoculação. As penetrações dos isolados ocorreram em maior proporção no abdome, seguido do tórax e cabeça do inseto, tendo sido mais frequente nas membranas do corpo do que nos escleritos.
ABSTRACT
The penetration ability of ARS-1590, ARS-1261 and ARS-1229 isolates of Zoophthora radicans (Brefeld) Batko on fifth-instar Empoasca kraemeri (Hoss & Moore) nymphs, at 20°C and 100% relative humidity (RH), were investigated and compared. The apressorium formation and isolates penetration began within the six hours after inoculation. The penetration occured in greater proportion in the abdome, followed by the thorax and head, more often through membranes than sclerites.
Foram analisados e comparados os processos de germinação e habilidade de infecção dos isolados ARS-1590, ARS-1261 e ARS-1229 de Zoophthora radicans (Brefeld) Batko sobre ninfas do 5º ínstar de Empoasca kraemeri (Hoss & Moore) em ambiente de 20°C e 100% de umidade relativa. A formação de apressório e penetração dos isolados iniciaram-se dentro do período de seis horas após a inoculação. As penetrações dos isolados ocorreram em maior proporção no abdome, seguido do tórax e cabeça do inseto, tendo sido mais frequente nas membranas do corpo do que nos escleritos.
ABSTRACT
The germination processes of ARS-1590, ARS-1261 and ARS-1229 isolates of Zoophthora radicans (Brefeld) Batko on fifth-instar Empoasca kraemeri (Ross & Moore, 1957) nymphs, at 20ºC and 100% relative humidity were investigated and compared. The primary conidia on the insect germinated within two hours after inoculation for all isolates. The total production of germ tubes tended to be equal to that of capilliconidium on the host body, 12 hours after inoculation. The secondary conidia proportion, among the forms produced by the primary conidia on the insect, did not exceed 25% in all body regions.
Foram analisados e comparados os processos de germinação dos isolados ARS-1590, ARS-1261 e ARS-1229 de Zoophthora radicans (Brefeld) Batko sobre ninfas do 5º ínstar de Empoasca kraemeri (Ross & Moore, 1957) a 20ºC e 100% de umidade relativa (RH). A germinação dos conídios primários dos isolados sobre o inseto iniciou-se dentro do período de duas horas após a inoculação. A produção total de tubos germinativos tendeu a se igualar a de capiloconídios sobre o corpo do hospedeiro, doze horas após a inoculação. A proporção de conídios secundários, dentro das formas geradas pelos conídios primários germinados sobre o inseto, não ultrapassou 25% em qualquer das regiões do corpo.
ABSTRACT
As a consequence of human exposure to carcinogenic aromatic amines, biochemical approaches to risk assessment have emphasized metabolic determinants of individual susceptibility and quantification of arylamine-macromolecular adducts. A known genetic polymorphism in humans, hepatic arylamine acetyltransferase activity, has been associated with differences in individual susceptibility to urinary bladder (slow acetylators) and colorectal (rapid acetylators) cancers. Similarly, the high specificity of an inducible human cytochrome P450 towards the N-oxidation of 4-aminobiphenyl and other aromatic amines is consistent with metabolic differences that can be used to predict relative human risk. Exposure to aromatic amines has also been documented, primarily by quantification of adducts with protein or DNA. Using 32P-postlabelling methods and a competitive avidin/biotin-amplified enzyme-linked immunoassay, we have estimated 4-aminobiphenyl-DNA adduct levels in surgical samples of human peripheral lung and urinary bladder epithelium and report values ranging from 2 to 97 adducts per 10(8) nucleotides.