Determining the source of Bacillus cereus and Bacillus licheniformis isolated from raw milk, pasteurized milk and yoghurt.

AIMS: Strain-specific detection of Bacillus cereus and Bacillus licheniformis in raw and pasteurized milk, and yoghurt during processing. METHODS AND RESULTS: Randomly selected isolates of Bacillus spp. were subjected to PCR analysis, where single primer targeting to the repetitive sequence Box elements was used to fingerprint the species. The isolates were separated into six different fingerprint patterns. The results show that isolates clustered together at about the 57% similarity level with two main groups at the 82% and 83% similarity levels, respectively. Contamination with identical strains both of B. cereus and B. licheniformis in raw and pasteurized milk was found as well as contaminated with different strains (in the case of raw milk and yoghurt/pasteurized milk and yoghurt). Several BOX types traced in processed milk samples were not discovered in the original raw milk. CONCLUSIONS: BOX-PCR fingerprinting is useful for characterizing Bacillus populations in a dairy environment. It can be used to confirm environmental contamination, eventually clonal transfer of Bacillus strains during the technological processing of milk. SIGNIFICANCE AND IMPACT OF THE STUDY: Despite the limited number of strains analysed, the two Bacillus species yielded adequately detectable banding profiles, permitting differentiation of bacteria at the strain level and showing their diversity throughout dairy processing.

Y-chromosomal variation in the Czech Republic.

To analyze the contribution of the Czech population to the Y-chromosome diversity landscape of Europe and to reconstruct past demographic events, we typed 257 males from five locations for 21 UEPs. Moreover, 141 carriers of the three most common haplogroups were typed for 10 microsatellites and coalescent analyses applied. Sixteen Hg's characterized by derived alleles were identified, the most common being R1a-SRY(10831) and P-DYS257*(xR1a). The pool of haplogroups within I-M170 represented the third most common clade. Overall, the degree of population structure was low. The ages for Hg I-M170, P-DYS257*(xR1a), and R1a-SRY(10831) ap peared to be comparable and compatible with their presence during or soon after the LGM. A signal of population growth beginning in the first millennium B.C. was detected. Its similarity among the three most common Hg's indicated that growth was characteristic for a gene pool that already contained all of them. The Czech population appears to be influenced, to a very moderate extent, by genetic inputs from outside Europe in the post-Neolithic and historical times. Population growth postdated the archaeologically documented introduction of Neolithic technology and the estimated central value coincides with a period of repeated changes driven by the development of metal technologies and the associated social and trade organization.

Y chromosomal haplogroup J as a signature of the post-neolithic colonization of Europe.

In order to attain a finer reconstruction of the peopling of southern and central-eastern Europe from the Levant, we determined the frequencies of eight lineages internal to the Y chromosomal haplogroup J, defined by biallelic markers, in 22 population samples obtained with a fine-grained sampling scheme. Our results partially resolve a major multifurcation of lineages within the haplogroup. Analyses of molecular variance show that the area covered by haplogroup J dispersal is characterized by a significant degree of molecular radiation for unique event polymorphisms within the haplogroup, with a higher incidence of the most derived sub-haplogroups on the northern Mediterranean coast, from Turkey westward; here, J diversity is not simply a subset of that present in the area in which this haplogroup first originated. Dating estimates, based on simple tandem repeat loci (STR) diversity within each lineage, confirmed the presence of a major population structuring at the time of spread of haplogroup J in Europe and a punctuation in the peopling of this continent in the post-Neolithic, compatible with the expansion of the Greek world. We also present here, for the first time, a novel method for comparative dating of lineages, free of assumptions of STR mutation rates.

Network analyses of Y-chromosomal types in Europe, northern Africa, and western Asia reveal specific patterns of geographic distribution.

In a study of 908 males from Europe, northern Africa, and western Asia, the variation of four Y-linked dinucleotide microsatellites was analyzed within three "frames" that are defined by mutations that are nonrecurrent, or nearly so. The rapid generation and extinction of new dinucleotide length variants causes the haplotypes within each lineage to diverge from one another. We constructed networks of "adjacent" haplotypes within each frame, by assuming changes of a single dinucleotide unit. Two small and six large networks were obtained, the latter including 94.9% of the sampled Y chromosomes. We show that the phenetic relationships among haplotypes, represented as a network, result largely from common descent and subsequent molecular radiation. The grouping of haplotypes of the same network thus fits an evolutionarily relevant criterion. Notably, this method allows the total diversity within a sample to be partitioned. Networks can be considered optimal markers for population studies, because reliable frequency estimates can be obtained in small samples. We present synthetic maps describing the incidence of different Y-chromosomal lineages in the extant human populations of the surveyed areas. Dinucleotide diversity also was used to infer time intervals for the coalescence of each network.

[Detection of the kappa-casein genotype in bulls using restriction fragment length polymorphisms]. / Detekcia genotypu kapa-kazeínu u býkov hovädzieho dobytka na základe polymorfizmu dlzky restrikcných fragmentov (FFLP).

Genetic analysis of RFLP was used for detection of genotype and allele frequencies of kappa-casein in Slovakian Spotted (60 bulls) and Slovakian Pinzgau (22 bulls) cattle breeds, according to the method of Medrano et al. (1990). DNA was prepared from the semen of animals. In the Slovakian Spotted breed the frequencies of alleles were as follows: kappa-CnA = 0.666, kappa-CnB = 0.333. The frequencies of kappa-Cn A/A, A/B and B/B genotypes were 45.00, 43.33 and 11.66, respectively. In the 22 tested Pinzgau bulls, the frequencies of the A and B alleles were 0.682 and 0.318, respectively. The percentual occurrence of genotypes was also determined: 54.54 (kappa-Cn A/A), 27.27 (kappa-Cn A/B) and 18.18 (kappa-Cn B/B). Comparing our own results with those of Mácha et al. (1968), who carried out the analysis of distribution of the kappa-casein genetic variants in the same cattle breeds by starch gel electrophoresis of the milk samples of 170 cows (Tab. I), the 16 p.c. decrease of the allele B in the Slovakian Spotted cattle, lasting about 30 years, is very remarkable. The occurrence of homozygous genotype BB decreased by 35 p.c. In addition, the homozygous genotype AA increased by about 18 p.c. and the occurrence of heterozygous genotype is also higher by nearly 17 p.c. In the same comparison of the Slovakian Pinzgau breed, no difference was estimated in the allele frequencies of kappa-Cn (Tab. I).(ABSTRACT TRUNCATED AT 250 WORDS)

[Polymorphism of alphas-casein in white short-haired polled goats]. / Polymorfizmus alfas-kazeínov u kozy bielej krátkosrstej bezrohej.

Distribution of alleles of the alphas-casein complex was studied by isoelectric focusing in the White Shorthaired Polled goat according to the method of Krause et al. (1988) and Mahé et al. (1993). In addition to the common alleles alpha s1-CnA and B, the alpha s1-CnE allele is described; it has not yet been observed in this breed. We are not able to confirm the occurrence of the alpha s1-CnC allele. At least one out of three defective mutants (alpha s1-CnD,F and 0) was found, nevertheless their identification was not discussed. The following percentile occurrence (Tab. I) of the above-mentioned alleles of alpha s1-casein was determined: alpha s1-CnA = 11.30; alpha s1-CnB = 38.26; alpha s1-CnC = 0; alpha s1-CnE = 17.39; alpha s1-CnX = 33.04 (the letter X indicates the defective mutants without specifying their type and number). Our results differ significantly from those of Boulamger et al. (1984), Grosclaude et al. (1987) and Trakovická (1992). Higher (in contrast to the French authors) and lower alpha s1-casein allele rates (as compared to Trakovická, 1992) were observed. The higher occurrence of the alpha s2-CnB is also conspicuous. However, our observations correspond to those according to which the "strong" alleles have higher frequencies in European breeds than in the French ones (Grosclaude et al., 1992-cit. Mahé et al., 1993). The alleles of alpha s2-casein were also investigated. The electrophoretic variant of the alpha s2-casein was observed next to the type B and located closer to the anode (suspected mutation); on that account it was named B-. This variant was also seen in a homozygous form.(ABSTRACT TRUNCATED AT 250 WORDS)