Heterokaryon incompatibility blocks virus transfer among natural isolates of black Aspergilli

1997 ◽  
Vol 32 (3) ◽  
pp. 209-217 ◽  
Author(s):  
A. D. van Diepeningen ◽  
Alfons J. M. Debets ◽  
Rolf F. Hoekstra
Keyword(s):  
Heterokaryon Incompatibility ◽  
Black Aspergilli ◽  
Virus Transfer ◽  
Natural Isolates

Double-stranded RNA mycoviruses in section Nigri of the Aspergillus genus

1994 ◽  
Vol 40 (4) ◽  
pp. 325-329 ◽  
Author(s):  
János Varga ◽  
Ferenc Kevei ◽  
Csaba Vágvölgyi ◽  
Aldwin Vriesema ◽  
James H. Croft
Keyword(s):  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
S1 Nuclease ◽  
Prolonged Incubation ◽  
Double Stranded Rna ◽  
Virus Like Particles ◽  
Aspergillus Foetidus ◽  
Virus Transfer ◽  
Natural Isolates ◽  
Rnase Treatment

Double-stranded RNA bands were detected electrophoretically in about 7% of natural isolates and in 13 of 51 collection strains belonging in section Nigri of the genus Aspergillus. The identity of these bands was proved by S1 nuclease and RNase treatment. Most of the virus-containing natural isolates came from Indonesia. Electron microscopic examination of the strains revealed the presence of virus-like particles in the mycelia of the strains examined. All of the virus-like particles were isometric and their size was around 30–35 nm, while some Indonesian isolates also contained virus-like particles in the size range 23–25 nm. It was possible to cure some of these strains of virus-like particles by mutagenic treatment. The four strains tested lost their virus-like particles and also their 'arginine–proline leaky' phenotype and became prototrophic. Virus transfer was possible among these four strains by protoplast fusion. It also proved possible to transfer mycoviruses into a more distantly related Aspergillus tubingensis strain by prolonged incubation of the polyethylene glycol treated protoplasts in osmotically stabilized medium. In spite of the finding that all Aspergillus foetidus and both Aspergillus heteromorphus strains examined contained double-stranded RNA segments and virus-like particles, no phenotypes related to the presence of these VLPs have been observed so far.Key words: Aspergillus niger, dsRNA, mycovirus, virus-like particles (VLPs).

SEARCH FOR NATURAL ISOLATES OF Bacillus thuringiensis FOR DEVELOPMENT OF ECOLOGICALLY FRIENDLY BIOLOGICALS

2018 ◽  
Vol 53 (5) ◽  
pp. 1062-1069
Author(s):  
S.D. Grishechkina ◽  
◽  
V.P. Ermolova ◽  
T.A. Romanova ◽  
A.A. Nizhnikov ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Natural Isolates

Population Genetics ofCaenorhabditis elegans: The Paradox of Low Polymorphism in a Widespread Species

Genetics ◽  
2003 ◽  
Vol 163 (1) ◽  
pp. 147-157 ◽  
Author(s):  
Arjun Sivasundar ◽  
Jody Hey
Keyword(s):  
Genetic Variation ◽  
Microsatellite Loci ◽  
Population Expansion ◽  
Widespread Species ◽  
C Elegans ◽  
Model Research ◽  
The World ◽  
Natural Isolates ◽  
History Of ◽  
Low Levels

AbstractCaenorhabditis elegans has become one of the most widely used model research organisms, yet we have little information on evolutionary processes and recent evolutionary history of this widespread species. We examined patterns of variation at 20 microsatellite loci in a sample of 23 natural isolates of C. elegans from various parts of the world. One-half of the loci were monomorphic among all strains, and overall genetic variation at microsatellite loci was low, relative to most other species. Some population structure was detected, but there was no association between the genetic and geographic distances among different natural isolates. Thus, despite the nearly worldwide occurrence of C. elegans, little evidence was found for local adaptation in strains derived from different parts of the world. The low levels of genetic variation within and among populations suggest that recent colonization and population expansion might have occurred. However, the patterns of variation are not consistent with population expansion. A possible explanation for the observed patterns is the action of background selection to reduce polymorphism, coupled with ongoing gene flow among populations worldwide.

Primary Keratinocytes Can Be Infected by Natural Isolates of Genital Human Papillomavirus

Intervirology ◽  
1995 ◽  
Vol 38 (5) ◽  
pp. 264-268 ◽  
Author(s):  
Aldo Venuti ◽  
Anna Di Lonardo ◽  
Lucio Standoli ◽  
Maria Luisa Marcante
Keyword(s):  
Human Papillomavirus ◽  
Primary Keratinocytes ◽  
Natural Isolates

ESCAPE FROM MATING-TYPE INCOMPATIBILITY IN BISEXUAL (A + a) NEUROSPORA HETEROKARYONS

1975 ◽  
Vol 17 (3) ◽  
pp. 441-449 ◽  
Author(s):  
A. M. DeLange ◽  
A. J. F. Griffiths
Keyword(s):  
Mating Type ◽  
Loss Of Function ◽  
Wild Type ◽  
Opposite Mating Type ◽  
Type Locus ◽  
Heterokaryon Incompatibility ◽  
Recessive Mutant ◽  
Type Rate ◽  
Wild Type Rate ◽  
Incompatibility Locus

In Neurospora crassa, strains of opposite mating type generally do not form stable heterokaryons because the mating type locus acts as a heterokaryon incompatibility locus. However, when one A and one a strain, having complementing auxotrophic mutants, are placed together on minimal medium, growth may occur, although the growth is generally slow. In this study, escape from such slow growth to that at a wild type or near-wild type rate was observed. The escaped cultures are stable heterokaryons, mostly having lost the mating type allele function from one component nucleus, so that the nuclear types are heterokaryon compatible. Either A or a mating type can be lost. This loss of function has been attributed to deletion since only one nuclear type could be recovered in all heterokaryons except one, but deletion spanning adjacent loci has been directly demonstrated in a minority of cases. Alternatively when one component strain is tol and the other tol+ (tol being a recessive mutant suppressing the heterokaryon incompatibility associated with mating type), escape may occur by the deletion or mutation of tol+, also resulting in heterokaryon compatibility. An induction mechanism for escape is speculated upon.

scholarly journals Preparation and properties of the specific anti-influenza virus transfer factor

2010 ◽  
Vol 6 (1) ◽  
Author(s):  
Chongbi Li ◽  
Lihua Huang ◽  
Yanping Wang ◽  
Xiangle Li ◽  
Shaowei Liang ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Transfer Factor ◽  
Virus Transfer

scholarly journals Inhibitory Reactions between Natural Isolates of Streptomyces

Microbiology ◽  
1985 ◽  
Vol 131 (5) ◽  
pp. 1149-1155
Author(s):  
D. A. R. McQUEEN ◽  
N. A. ANDERSON ◽  
J. L. SCHOTTEL
Keyword(s):  
Natural Isolates

scholarly journals Studies on the Proteolytic Enzymes of Black Aspergilli

1958 ◽  
Vol 22 (1) ◽  
pp. 32-34 ◽  
Author(s):  
Fumihiko YOSHIDA ◽  
Michitaro NAGASAWA
Keyword(s):  
Proteolytic Enzymes ◽  
Black Aspergilli
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