Organization Of Multigene Families Research Articles

Karyological Study of Acanthocephalus lucii (Echinorhynchida): The Occurrence of B Chromosomes in Populations from PCB-Polluted Waters

In this study, we performed a cytogenetic analysis of Acanthocephalus lucii specimens from three sites with different levels of environmental pollution. Standard and fluorochrome staining (CMA3/DAPI), fluorescence in situ hybridization (FISH) with 18S rDNA and histone H3 probes, and silver impregnation were performed. Chromosome complements of 2n = 7/8 (male/female), n = 1m + 2sm + 1a (X), and CMA3-positive bands in all chromosomes were found in all three populations. FISH revealed one 18S rDNA locus on the X chromosome and one locus of H3 histone genes on the first chromosome pair. At the intraspecific level, the populations differed in the presence of supernumerary B chromosomes, which were found in all specimens from Zemplínska Šírava and in 89.4% of specimens from the Laborec River, but not at the reference site. The first two sites are considered to be water bodies with high toxin contamination. Based on this fact, we assume an increased frequency of chromosome breaks leading to the formation of DNA fragments that have the potential to form B chromosomes. The present results add to the very limited data on the organization of multigene families in the genome of Acanthocephala and suggest a possible causal link between water pollution and the occurrence of B chromosomes in fish parasites.

Two Novel Multigene Families, 530 and 300, in the Terminal Variable Regions of African Swine Fever Virus Genome

Here, we describe two novel multigene families (MGF) present in the terminal variable regions of the African swine fever virus (ASFV) genome. MGF530 includes at least six related ORFs (averaging 530 amino acids) containing four well-conserved domains and amino acid identities ranging from 24 to 55%. MGF300 is composed of three ORFs (averaging 300 amino acids) containing three highly conserved domains and amino acid identities ranging from 25 to 46%. Amino terminal regions of predicted MGF530 and 300 proteins share significant similarity with each other and with the comparable regions of previously characterized MGF360 ORFs. Members of both MGF530 and 300 are transcribed in ASFV-infected porcine macrophages. These results indicate that the composition and organization of MGF in the terminal variable region of the ASFV genome are more complex than previously recognized.