scholarly journals Chiasmata in spermatocytes of Drosophila melanogaster

1964 ◽  
Vol 5 (1) ◽  
pp. 80-84 ◽  
Author(s):  
B. M. Slizynski
Keyword(s):  
Drosophila Melanogaster ◽  
Type Strain ◽  
Wild Type Strain ◽  
Chromosome Behaviour ◽  
Wild Type ◽  
Homologous Chromosomes ◽  
Translocation Heterozygote ◽  
Positive Material ◽  
Chromosome Material

On the basis of chromosome behaviour in three strains of Drosophila melanogaster males—a wild-type strain, a translocation heterozygote strain and a double translocation strain—it is concluded that the cytologically detected apparent chiasmata in the autosomes are only surface associations of homologous chromosomes and do not involve exchange of chromosome material. Such chiasma-like associations occur also between non-homologous chromosomes. The stainable, Feulgen-positive material of the chromosomes is thought to be responsible for the surface associations.

scholarly journals Reproduction and endoreduplication in Drosophila melanogaster Meig. when influenced by lead nitrate

2020 ◽  
Vol 27 ◽  
pp. 303-308
Author(s):  
V. Yu. Strashnyuk ◽  
O. V. Taglina
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Glands ◽  
Type Strain ◽  
Wild Type Strain ◽  
Lead Nitrate ◽  
Wild Type ◽  
Reproductive Ability ◽  
Dose Dependent Decrease ◽  
Drosophila Cells ◽  
Dose Dependent

Aim. The purpose of investigation was to study the reproductive ability and polyteny degree of chromosomes in Drosophila melanogaster Meig. under the influence of various concentrations of lead nitrate. Methods. Canton-S wild-type strain was used as the material. Flies developed on standard sugar-yeast medium, to which in the experiment lead nitrate was added in concentrations of 0.1, 1, and 10 mg/ml. The reproductive ability of the strain was evaluated by the number of adult offspring. The polyteny degree of chromosomes was studied on squashed preparations of larva salivary glands stained with acetoorsein by cytomorphometry. The preparations were obtained at late 3rd instar. Results. The number of adult offsprings decreased when lead nitrate was added to the nutrient medium: at a concentration of 0.1 mg/ml – by 22.8 %, at 1 mg/ml – by 38.9 %. A concentration of 10 mg/ml was lethal. Males showed greater sensitivity to the drug compared to females. The degree of polyteny of chromosomes in the salivary glands of larvae decreased on average by 5.0–6.5 %. Conclusions. Lead nitrate causes a significant, dose-dependent decrease in the reproductive ability of fruit flies and has a toxic effect on Drosophila cells, inhibiting the process of endoreduplication. Keywords: Drosophila melanogaster Meig., heavy metals, fecundity, giant chromosomes, polyteny.

Notizen: A New Mutant Affecting Aldehyde Oxidase in Drosophila melanogaster

1979 ◽  
Vol 34 (3-4) ◽  
pp. 304-305 ◽  
Author(s):  
Michael M. Bentley ◽  
John H. Williamson
Keyword(s):  
Drosophila Melanogaster ◽  
Type Strain ◽  
Wild Type Strain ◽  
Aldehyde Oxidase ◽  
Heat Stability ◽  
Chromosome 2 ◽  
Control Strain ◽  
Wild Type ◽  
Mutant Stock ◽  
Wild Type Control

Abstract A new locus, Aldox-2, which affects the activity and heat stability of aldehyde oxidase in D. melanogaster is described. The Aldox-2 locus is localized to map position 86 on chromosome 2, between c and px. Aldehyde oxidase activity in Aldox-2 homozygotes is approximately 25 - 30% that of the Oregon-R wild-type control strain. The enzyme from the mutant stock is much more heat labile than is the enzyme from the wild-type strain. Both the activity and heat phenotypes are completely recessive.

scholarly journals Influence of the population genetic background on the persistency of a recessive lethal in Drosophila melanogaster

1971 ◽  
Vol 17 (2) ◽  
pp. 103-111 ◽  
Author(s):  
Karl H. Ytterborn
Keyword(s):  
Drosophila Melanogaster ◽  
Inbred Strain ◽  
Genetic Background ◽  
Type Strain ◽  
Detrimental Effect ◽  
Wild Type Strain ◽  
Gene Pools ◽  
Wild Type ◽  
Original Population ◽  
Heterozygous Carriers

SUMMARYIn a population of Drosophila melanogaster started from an inbred wild-type strain the recessive second chromosome lethal studied had shown overdominance which after many generations was lost. In the present study the persistence of this lethal was tested in three series each of five populations. The genetic backgrounds of the different series of populations were obtained from (a) the inbred strain, (b) the above original population after the overdominance had been lost, and (c) a population started from the same inbred strain and where another lethal had shown overdominance which subsequently had been lost. The lethal was overdominant in the (a) background but detrimental to the heterozygous carriers on the other backgrounds. The detrimental effect of the lethal was stronger in the (b) background than in the (c) background. The varying behaviour of the lethal is possibly due to different adapted background genotypes and/or different degrees of heterozygosity of the gene pools.

scholarly journals Melatonin influence on Drosophila melanogaster life span at different light regimes

2008 ◽  
Vol 6 (3) ◽  
pp. 24-32
Author(s):  
Aleksey A Moskalev ◽  
Anna V Krementsova ◽  
Olga A Malysheva
Keyword(s):  
Dna Repair ◽  
Drosophila Melanogaster ◽  
Data Analysis ◽  
Life Span ◽  
Type Strain ◽  
Wild Type Strain ◽  
Combined Effects ◽  
Wild Type ◽  
Maximum Life Span ◽  
Light Regimes

It was investigated the combined effects of different light regimes (round-the-clock lighting or darkening) and antioxidant melatonin on Drosophila melanogaster life span of wild type strain Canton-S,mutant strain with defect of red-ox system (Sod) and mu tant strain with disturbance of excision DNA repair (mus210). It was revealed, that maintenance of Drosophila imago at round-the-clock lighting leads to decrease of mean and/or maximum life span with compare to being at darkening. Adding of melatonin to Drosophila meal induces the geroprotector effects, mainly, in dark conditions. The effects mentioned above were most expressed in strain with mutation of Sod. All effects have revealed in both sexes. The data analysis has shown that mechanisms of different light regimes and melatonin influ ence on life span are rather different.

scholarly journals Effects of Mutations of RAD50, RAD51, RAD52, and Related Genes on Illegitimate Recombination in Saccharomyces cerevisiae

Genetics ◽  
1996 ◽  
Vol 142 (2) ◽  
pp. 383-391 ◽  
Author(s):  
Yasumasa Tsukamoto ◽  
Jun-ichi Kato ◽  
Hideo Ikeda
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Quantitative Analysis ◽  
Structural Analysis ◽  
Recombination Rate ◽  
Type Strain ◽  
Negative Selection ◽  
Wild Type Strain ◽  
Illegitimate Recombination ◽  
Wild Type ◽  
In The Wild

Abstract To examine the mechanism of illegitimate recombination in Saccharomyces cerevisiae, we have developed a plasmid system for quantitative analysis of deletion formation. A can1 cyh2 cell carrying two negative selection markers, the CAN1 and CYH2 genes, on a YCp plasmid is sensitive to canavanine and cycloheximide, but the cell becomes resistant to both drugs when the plasmid has a deletion over the CAN1 and CYH2 genes. Structural analysis of the recombinant plasmids obtained from the resistant cells showed that the plasmids had deletions at various sites of the CAN1-CYH2 region and there were only short regions of homology (1-5 bp) at the recombination junctions. The results indicated that the deletion detected in this system were formed by illegitimate recombination. Study on the effect of several rad mutations showed that the recombination rate was reduced by 30-, 10-, 10-, and 10-fold in the rad52, rad50, mre11, and xrs2 mutants, respectively, while in the rud51, 54, 55, and 57 mutants, the rate was comparable to that in the wild-type strain. The rad52 mutation did not affect length of homology at junction sites of illegitimate recombination.

scholarly journals The role of Zur-regulated lipoprotein A in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles in Acinetobacter baumannii

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Nayeong Kim ◽  
Hyo Jeong Kim ◽  
Man Hwan Oh ◽  
Se Yeon Kim ◽  
Mi Hyun Kim ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Mutant Strain ◽  
Antimicrobial Susceptibility ◽  
Type Strain ◽  
Wild Type Strain ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Wild Type ◽  
Bacterial Morphology

Abstract Background Zinc uptake-regulator (Zur)-regulated lipoprotein A (ZrlA) plays a role in bacterial fitness and overcoming antimicrobial exposure in Acinetobacter baumannii. This study further characterized the zrlA gene and its encoded protein and investigated the roles of the zrlA gene in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles (OMVs) in A. baumannii ATCC 17978. Results In silico and polymerase chain reaction analyses showed that the zrlA gene was conserved among A. baumannii strains with 97–100% sequence homology. Recombinant ZrlA protein exhibited a specific enzymatic activity of D-alanine-D-alanine carboxypeptidase. Wild-type A. baumannii exhibited more morphological heterogeneity than a ΔzrlA mutant strain during stationary phase. The ΔzrlA mutant strain was more susceptible to gentamicin than the wild-type strain. Sizes and protein profiles of OMVs were similar between the wild-type and ΔzrlA mutant strains, but the ΔzrlA mutant strain produced 9.7 times more OMV particles than the wild-type strain. OMVs from the ΔzrlA mutant were more cytotoxic in cultured epithelial cells than OMVs from the wild-type strain. Conclusions The present study demonstrated that A. baumannii ZrlA contributes to bacterial morphogenesis and antimicrobial resistance, but its deletion increases OMV production and OMV-mediated host cell cytotoxicity.

scholarly journals FixJ family regulator AcfR of Azorhizobium caulinodans is involved in symbiosis with the host plant

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wei Liu ◽  
Xue Bai ◽  
Yan Li ◽  
Haikun Zhang ◽  
Xiaoke Hu
Keyword(s):  
Signal Transduction ◽  
Host Plant ◽  
Type Strain ◽  
Wild Type Strain ◽  
Response Regulator ◽  
Azorhizobium Caulinodans ◽  
Wild Type ◽  
Response Regulators ◽  
Free Living ◽  
Two Component

Abstract Background A wide variety of bacterial adaptative responses to environmental conditions are mediated by signal transduction pathways. Two-component signal transduction systems are one of the predominant means used by bacteria to sense the signals of the host plant and adjust their interaction behaviour. A total of seven open reading frames have been identified as putative two-component response regulators in the gram-negative nitrogen-fixing bacteria Azorhizobium caulinodans ORS571. However, the biological functions of these response regulators in the symbiotic interactions between A. caulinodans ORS571 and the host plant Sesbania rostrata have not been elucidated to date. Results In this study, we identified and investigated a two-component response regulator, AcfR, with a phosphorylatable N-terminal REC (receiver) domain and a C-terminal HTH (helix-turn-helix) LuxR DNA-binding domain in A. caulinodans ORS571. Phylogenetic analysis showed that AcfR possessed close evolutionary relationships with NarL/FixJ family regulators. In addition, six histidine kinases containing HATPase_c and HisKA domains were predicted to interact with AcfR. Furthermore, the biological function of AcfR in free-living and symbiotic conditions was elucidated by comparing the wild-type strain and the ΔacfR mutant strain. In the free-living state, the cell motility behaviour and exopolysaccharide production of the ΔacfR mutant were significantly reduced compared to those of the wild-type strain. In the symbiotic state, the ΔacfR mutant showed a competitive nodule defect on the stems and roots of the host plant, suggesting that AcfR can provide A. caulinodans with an effective competitive ability for symbiotic nodulation. Conclusions Our results showed that AcfR, as a response regulator, regulates numerous phenotypes of A. caulinodans under the free-living conditions and in symbiosis with the host plant. The results of this study help to elucidate the involvement of a REC + HTH_LuxR two-component response regulator in the Rhizobium-host plant interaction.

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