Karyotype of Philodryas nattereri and Philodryas olfersii with a comparative analysis of the Dipsadidae family

Cytogenetic studies of Philodryas nattereri and Philodryas olfersii revealed a diploid chromosome number 2n = 36 for both species (3 metacentrics, 4 submetacentrics, and 10 acrocentrics, with a fundamental number of 51 and 52, respectively). The results obtained are novel and similar to those previously described for species belonging to the Dipsadidae family. The conventional karyotype is also novel and divergent from other species of the Dipsadidae family, where a higher proportion of macrochromosomes predominate, revealing two distinct groups in this family. The data are reported and discussed considering the cytotaxonomy of the family. These results strongly support the current view that chromosomal alterations, such as centric fusion and Robertsonian's translocations, seems to support the distinct importance of chromosomal rearrangements in speciation within this group.

Chromosomes of Gymnothorax funebris and the karyotypical differentiation within Gymnothorax (Anguilliformes: Muraenidae)

Cytogenetic studies in Gymnothorax funebris revealed a diploid chromosome number 2n = 42 (6 metacentrics, 4 submetacentrics, and 32 acrocentrics, FN = 52). The results obtained are novel and similar to those previously described for species belonging to Muraenidae family. The conventional karyotype is also novel and divergent from other species of the genus Gymnothorax, where a higher proportion of metacentric chromosomes predominate. The data are reported and discussed considering the cytotaxonomy of the genus. These results strongly support the current view that chromosomal alterations such as centric fusion and Robertsonian's translocations have an important role in the evolution of this group.

Occurrence of Listeria spp. in critical control points and the environment of Minas Frescal cheese processing

Critical control points (CCPs) associated with Minas Frescal cheese (a Brazilian soft white cheese, eaten fresh) processing in two dairy factories were determined using flow diagrams and microbiological tests for detection of Listeria monocytogenes and other species of Listeria. A total of 218 samples were collected along the production line and environment. The CCPs identified were reception of raw milk, pasteurization, coagulation and storage. Thirteen samples were positive for Listeria; 9 samples were Listeria innocua, 2 were Listeria grayi and 2 were L. monocytogenes. In factory A, Listeria was found in 50% of raw milk samples, 33.3% of curd samples, 16.7% of pasteurized milk samples, 16.7% of cheese samples and 25% of rubber pipes used to transport the whey. The microorganism was not obtained from environmental samples in this plant. In factory B, Listeria was found in one sample of raw milk (16.7%) and in three samples of environment (17.6%) and L. monocytogenes was obtained from raw milk (16.7%) and the floor of the cheese refrigeration room (14.3%). Two serotypes, 4b and 1/2a, were observed among the strains of L. monocytogenes isolated, both which are frequently involved in outbreaks of food-borne listeriosis and sporadic cases of the disease all over the world.

Purification and partial characterization of a lectin from Canavalia grandiflora benth. seeds

A D-glucose/D-mannose specific lectin from seeds of Canavalia grandiflora (ConGF) was purified by affinity chromatography on Sephadex G-50. By SDS-PAGE ConGF yielded three protein bands with apparent molecular masses of 29-30 kDa (alpha chain), 16-18 kDa (beta fragment) and 12-13 kDa (gamma fragment), like other related lectins from the genus Canavalia (Leguminosae). ConGF strongly agglutinates rabbit erythrocytes, has a high content of ASP and SER, and its N-terminal sequence (30 residues) is highly similar to the sequences of other related lectins from subtribe Diocleinae.