scholarly journals Entomophthora muscae — moisture as a factor affecting its transmission and conidial germination

2014 ◽  
Vol 16 (1) ◽  
pp. 133-139 ◽  
Author(s):  
John P. Kramer
Keyword(s):  
Microscopical Study ◽  
Conidial Germination ◽  
Dominant Form ◽  
Entomophthora Muscae ◽  
House Flies ◽  
Resting Spores

The role played by moisture in the transmission of <i>Entomophthora muscae</i> and in the germination of its conidia was investigated. A majority of adult house flies exposed to conidial showers that fell upon surfaces covered with droplets of condensation acquired the parasite, while no flies exposed to conidial showers that fell upon dry surfaces did so. A microscopical study of conidial showers showed that germination was practically non-existent on dry surfaces while a vast majority of conidia that fell upon a droplet-covered surface germinated. A method for the <i>in vivo</i> culture of <i>E. muscae</i> was developpd and 11 serial passages of the fungus were achieved. Resting spores rather than conidia became the dominant form produced in the cadavers, and flies in a twelfth group remained unifected.

Formation and germination of resting spores from different strains from the Entomophthora muscae complex produced in Musca domestica

2001 ◽  
Vol 79 (9) ◽  
pp. 1076-1082 ◽  
Author(s):  
Lene Thomsen ◽  
José Bresciani ◽  
Jørgen Eilenberg
Keyword(s):  
Musca Domestica ◽  
House Fly ◽  
Spore Production ◽  
Spore Formation ◽  
Entomophthora Muscae ◽  
Resting Spore ◽  
Resting Spores ◽  
Group B ◽  
Different Strains

Three species within the Entomophthora muscae (Cohn) Fresenius complex (Entomophthora schizophorae Keller & Wilding, E. muscae s.str., and E. muscae "group B") were investigated for resting spore formation in vivo in the house fly (Musca domestica L.). Resting spores of E. muscae group B were experimentally induced from August to the beginning of February, while no resting spores were ever observed in E. schizophorae infected M. domestica or in flies infected by E. muscae s.str. originating from M. domestica. When newly dead fly cadavers containing E. muscae group B resting spores were kept moist, cystidia emerged from the abdomen; this is the first report of cystidia in the genus Entomophthora. Resting spore production was significantly affected by both temperature and E. muscae group B strain. More infected flies formed resting spores when kept 1 week at 10°C compared with constant exposure at 22°C, but the tendency of the different E. muscae group B strains to form resting spores persisted with shifting temperatures. After 4 months of incubation under natural winter conditions in Denmark, E. muscae group B resting spores germinated on water agar at 20°C with a 16 h light : 8 h dark photoperiod within 1 week, but no germ conidia were observed.Key words: Entomophthorales, Entomophthora muscae complex, Diptera, Musca domestica, resting spore formation, resting spore germination.

The differentiation of the chick chorionic epithelium: an experimental study

Development ◽  
1974 ◽  
Vol 32 (2) ◽  
pp. 365-374
Author(s):  
Roberto Narbaitz ◽  
Pierre P. Tellier
Keyword(s):  
Experimental Study ◽  
Parathyroid Hormone ◽  
Synthetic Medium ◽  
External Source ◽  
Microscopical Study ◽  
Electron Microscopical Study ◽  
Parathyroid Glands ◽  
Vascular Changes ◽  
Electron Microscopical

An electron microscopical study of the chorionic epithelium under two different experimental situations was conducted in order to gain knowledge on the mechanisms controlling the differentiation of ‘calcium-absorbing’ cells. In chorioallantoic membranes from 10-day-old embryos cultured on a semi-synthetic medium, the chorion became avascular but ‘calcium-absorbing’ cells differentiated, showing that the differentiation of these cells is not dependent on the vascular changes which in vivo occur simultaneously. The number of ‘calcium-absorbing’ cells was much larger in the explants cultured on parathyroid hormone-enriched medium than in controls, indicating that the hormone is capable of stimulating their differentiation. Since it is known that parathyroid glands are active at the time in which ‘calcium-absorbing’ cells normally appear, our results suggest that the hormone may be the normal inductor of their differentiation. Finally, a small number of ‘calcium-absorbing’ cells differentiated in vivo in a portion of chorion which had been artificially separated from the shell membranes, showing that their differentiation does not depend on the proximity of the external source of calcium.

scholarly journals Efficiency of a new Waitea circinata extract against rice pathogens

2021 ◽  
Vol 51 ◽  
Author(s):  
Jacqueline Campos Borba de Carvalho ◽  
Amanda Abdallah Chaibub ◽  
Kellen Cristhina Inácio Sousa ◽  
Denise Candini de Brito ◽  
Marta Cristina Corsi de Filippi ◽  
...  
Keyword(s):  
Rice Blast ◽  
Mycorrhizal Fungus ◽  
Conidial Germination ◽  
Appressorium Formation ◽  
Vitro Assay ◽  
Rice Pathogens ◽  
Waitea Circinata ◽  
Mycelial Mass

ABSTRACT Waitea circinata (Warcup & Talbot) is an orchid antagonist mycorrhizal fungus with biocontrol potential against rice pathogens. This study aimed to optimize the extraction method, obtain a new extract and evaluate its efficiency against rice pathogens in vitro and in vivo, as well as to compare it with other extraction methods and W. circinata. The extracts were obtained and screened for in vitro growth inhibition against the pathogens Cochliobolus miyabeanus, Monographella albescens and Sarocladium oryzae, using the following extracts: mycelial, crude, lyophilized and mycelial mass. An additional in vitro assay was performed with the principal rice pathogen (Magnaporthe oryzae), in order to evaluate the conidial germination and appressorium formation. Based on this evaluation, the lyophilized and mycelial mass extracts were tested in vivo against rice blast (M. oryzae) and compared to the W. circinata mycelial suspension, in different application forms (simultaneous and previous). The mycelial mass extract inhibited all the pathogens, and the crude and lyophilized extracts inhibited C. miyabeanus and M. albescens, respectively. The mycelial mass extract inhibited the M. oryzae conidial germination and appressorium formation by 80 %, and the simultaneous and previous applications suppressed the rice blast by 94 %. These results indicate that the new extract can be used to control rice pathogens.

Gain of function of Malate Dehydrogenase 2 (MDH2) and familial hyperglycemia

2021 ◽  
Author(s):  
Prapaporn Jungtrakoon Thamtarana ◽  
Antonella Marucci ◽  
Luca Pannone ◽  
Amélie Bonnefond ◽  
Serena Pezzilli ◽  
...  
Keyword(s):  
Insulin Secretion ◽  
Malate Dehydrogenase ◽  
Missense Variant ◽  
Gain Of Function ◽  
Dominant Form ◽  
Functional Studies ◽  
The Us ◽  
Glucose Stimulated Insulin Secretion

Abstract Objective We set out to identify the genetic cause of hyperglycemia in multigenerational families with an apparent autosomal dominant form of adult-onset diabetes not due to mutations in known monogenic diabetes genes. Methods Existing Whole Exome Sequencing (WES) data were used to identify exonic variants segregating with diabetes in 60 families from the US and Italy. Functional studies were carried out in vitro (transfected MIN6-K8 cells) and in vivo (Caenorhabditis elegans) to assess the diabetogenic potential of two variants in the Malate Dehydrogenase 2 (MDH2) gene linked with hyperglycemia in two of the families. Results A very rare mutation (p.Arg52Cys) in MDH2 strongly segregated with hyperglycemia in one family from the US. An infrequent MDH2 missense variant (p.Val160Met) also showed disease co-segregation in a family from Italy, although with reduced penetrance. In silico, both Arg52Cys and Val160Met were shown to affect MDH2 protein structure and function. In transfected HepG2 cells, both variants significantly increased MDH2 enzymatic activity, thereby decreasing the NAD+/NADH ratio - a change known to affect insulin signaling and secretion. Stable expression of human wild type MDH2 in MIN6-K8 cell lines enhanced glucose- and GLP-1-stimulated insulin secretion. This effect was blunted by the Cys52 or Met160 substitutions. Nematodes carrying equivalent changes at the orthologous positions of the mdh-2 gene showed impaired glucose-stimulated insulin secretion. Conclusions Our findings suggest a central role of MDH2 in human glucose homeostasis and indicate that gain of function variants in this gene may be involved in the etiology of familial forms of diabetes.

In vivo and in vitro fate of fenvalerate in house flies

1990 ◽  
Vol 38 (2) ◽  
pp. 140-152 ◽  
Author(s):  
D.L. Bull ◽  
N.W. Pryor
Keyword(s):  
House Flies

Culture of Entomophthora muscae in vivo and its infectivity for six species of muscoid flies

1981 ◽  
Vol 76 (3) ◽  
pp. 139-143 ◽  
Author(s):  
J. P. Kramer ◽  
D. C. Steinkraus
Keyword(s):  
Entomophthora Muscae
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