Rearrangements in the salivary gland chromosomes of<i>Chironomus riparius</i>Mg. (Diptera, Chironomidae) following exposure to lead

Michailova, Paraskeva; Ilkova, Julia; Petrova, N. A.; White, Kenneth

doi:10.1080/00087114.2001.10589246

Cited by 19 publications

(14 citation statements)

References 16 publications

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“…The S values at each of the three different Pb concentrations were significantly higher than in control larvae but not significantly correlated to the three Pb concentrations (rs = 0.8; P = 0.2). In Cr-treated larvae, aberrations were found in 15% of the cells while in control larvae their frequency was 2% (Michailova et al 2001a Figure 4. ), In treated larvae, no differences in S values were observed among the three Cr concentrations possibly because Cr ions do not last so long in the dissolved states in which they can be bioaccumulated (Namieśnik & Rabajczyk 2010).…”

Section: Genotoxic Effects Of Experimental Exposure To Specific Tracementioning

confidence: 99%

“…In the Pb-and Cu-exposed larvae, there was a dose-response relationship between the concentration of the trace-metal ions and the frequencies of decondensations (Michailova et al 2001a(Michailova et al ,b, 2006. There were also reactions that were seemingly specific to the exposure to a given ion.…”

Section: Genotoxic Effects Of Experimental Exposure To Specific Tracementioning

confidence: 99%

“…Trivalent salts of Cr (III) are absorbed by organisms with difficulty. Another explanation is that the ability of larvae to incorporate Cr compounds by endocytosis was limited (Michailova et al 2001a). In contrast, Pb and Al had strong effects on NOR activity.…”

Section: Genotoxic Effects Of Experimental Exposure To Specific Tracementioning

confidence: 99%

“…In this way the supposed genotoxic effects of specific trace metals observed in the field can be measured (Michailova & Belcheva 1990;Michailova et al 2001a,b;Michailova et al 2003Michailova et al , 2006. So far, four trace metals were tested in laboratory experiments: Al, Pb, Cr and Cu (Michailova et al 2001a(Michailova et al ,b, 2003(Michailova et al , 2006. Al, Pb and Cr free ions were tested separately with a chronic exposure, starting from fertilized egg masses up to the last larval stage.…”

Section: Genotoxic Effects Of Experimental Exposure To Specific Tracementioning

confidence: 99%

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Chironomids (Diptera) and their salivary gland chromosomes as indicators of trace-metal genotoxicity

Michailova

Sella

Petrova

2012

Italian Journal of Zoology

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The long-term impact of pollution in freshwater aquatic environments can be assessed realistically only if the mutagenic effects of pollutants on organisms inhabiting aquatic biotopes are evaluated. To do this, the larvae of Chironomids (Diptera) can serve as suitable indicators of potential environmental genotoxicity. These larvae exhibit aberrations in their polytene chromosomes, which, when analyzed, indicate an early response to toxicity more efficiently than morphological analysis, up to now the usual technique. Chironomids have excellent salivary gland chromosomes with well-defined bands and permanent somatic pairing, where there are two important regions of active transcription-Balbiani rings (BRs) and Nucleolar organizers (NOR). We have described the responses of different Chironomid species in two situations: in the field and in the laboratory, where we performed Cr, Al, Pb and Cu trace-metal-exposure experiments with Chironomus riparius. In both situations, the genome response consisted in a statistically significant increase in somatic chromosome aberrations and decrease in BR and NOR activity to levels lower than those of larvae under standard conditions. The main chromosome aberrations consisted in inversions, amplifications, deletions and deficiencies. Deletions in the chromosome G in C. riparius transformed it into a pompon-like structure. Chromosome aberrations were not randomly distributed: they occurred mainly in sites with repetitive DNA elements that have a highly interspersed location in the C. riparius genome. Hence C. riparius is the species most likely to produce aberrations and can be used as a model for cost-effective monitoring of the early genomic response to trace metals and other stress agents.

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Section: Genotoxic Effects Of Experimental Exposure To Specific Tracementioning

confidence: 99%

Section: Genotoxic Effects Of Experimental Exposure To Specific Tracementioning

confidence: 99%

Section: Genotoxic Effects Of Experimental Exposure To Specific Tracementioning

confidence: 99%

Section: Genotoxic Effects Of Experimental Exposure To Specific Tracementioning

confidence: 99%

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Chironomids (Diptera) and their salivary gland chromosomes as indicators of trace-metal genotoxicity

Michailova

Sella

Petrova

2012

Italian Journal of Zoology

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“…Planello et al (2007) record a decrease in NOR activity after Cd treatment using rDNA immunofluorescent probes. Similarly the NORs of other species of Chironomidae exposed to copper, Pb, dimethylnitrosamine and other chemicals show a decrease in activity (Aziz et al, 1991;Bentivegen & Cooper, 1993;Michailova et al, 2001aMichailova et al, , b, 2006. In M. pallidula there was a significant change in the activity of the NOR located on chromosome EF from high to intermediate.…”

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confidence: 99%

Genomic alterations recorded in two species of Chironomidae (Diptera) in the Upper Jurassic limestone area of the Ojców National Park in Poland attributable to natural and anthropogenic factors

Michailova¹,

Szarek-Gwiazda²,

Kownacki³

et al. 2012

Eur. J. Entomol.

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Abstract. The Ojców National Park is situated in southern Poland in an area of Jurassic limestone, which determines the hydrochemistry of the water in the River Pr dnik. The geochemical index of the sediment in the River Pr dnik indicated it is moderately polluted with Pb and Zn, and heavily polluted with Cd compared to unpolluted sediment. The effect of natural and anthropogenic sources on the sediment in the River Pr dnik and in appearing of structural and functional alterations in the salivary gland chromosomes of two species of Chironomidae, Micropsectra pallidula and Polypedilum convictum, was investigated. Two types of chromosomal rearrangements (inherited and somatic) were identified in the species studied. Inherited heterozygous inversions occurred at a higher frequency (between 5.55%-57.81%) and may have local adaptive value. In M. pallidula a karyotype divergence consisting of fixed chromosome inversions on arms B and E was recorded. As somatic chromosome rearrangements can be caused by stress agents, we suggest that the somatic aberrations in both of the species studied indicate the existence of pollution, i.e. induced stress. On the basis of these somatic rearrangements the somatic index of both species was defined: M. pallidula -0.346, P. convictum -0.555. In addition to these rearrangements functional alterations in key structures, Balbiani rings (BRs) and the nucleolar organizer region (NOR) located on chromosome EF, which significantly decreased their transcriptional activity, were recorded in M. pallidula. Changes in the appearance of the telomere region on chromosome G in P. convictum was considered to be a response to the environmental conditions in the River Pr dnik. It was shown that polytene chromosomes are very sensitive to environmental changes and can be used to detect pollutants in aquatic ecosystems.

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Somatic breakpoints, distribution of repetitive DNA and non-LTR retrotransposon insertion sites in the chromosomes of Chironomus piger Strenzke (Diptera, Chironomidae)

Michailova

Ilkova

Hankeln³

et al. 2008

Genetica

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Structural aberrations, their frequency and distribution as well as distribution of the tandem repetitive minisatellite DNA clusters of Alu and Hinf elements and two retroelements, the LINE NLRCth1 and the SINE CTRT1, were analyzed in the genome of the chironomid C. piger Strenzke larvae from a Bulgarian population. A consistent somatic variability in the structure of the polytene chromosomes was detected, showing that the C. piger genome is more actively rearranging than supposed before. Breakpoints were concentrated in proximal parts of chromosomes significantly more often than in distal parts. By FISH analysis we could detect only one locus containing Alu elements and 38 Hinf cluster loci which appear to be dispersed equally all over the chromosomes. The retrotransposons NLRCth1 and CTRT1 are present only in a few loci, but highly variant among different individuals. The mean number of NLRCth1 sites per individual was 18.4 +/- 2.09 and of CTRT1 was 54.8 +/- 8.42. A third of breakpoint locations were close to or coincide with a locus occupied by a retroelement (either NLRCth1 or CTRT1). Nineteen percent of breakpoints coincided with Hinf repetitive DNA elements. Some breakpoints were identical in the two sibling species C. piger and C. riparius Meigen (syn.: C. thummi thummi) and are considered as conserved hot spots of chromosome breakage.

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Rearrangements in the salivary gland chromosomes ofChironomus ripariusMg. (Diptera, Chironomidae) following exposure to lead

Cited by 19 publications

References 16 publications

Chironomids (Diptera) and their salivary gland chromosomes as indicators of trace-metal genotoxicity

Chironomids (Diptera) and their salivary gland chromosomes as indicators of trace-metal genotoxicity

Genomic alterations recorded in two species of Chironomidae (Diptera) in the Upper Jurassic limestone area of the Ojców National Park in Poland attributable to natural and anthropogenic factors

Somatic breakpoints, distribution of repetitive DNA and non-LTR retrotransposon insertion sites in the chromosomes of Chironomus piger Strenzke (Diptera, Chironomidae)

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