Biomass and enzymatic activities of marine bacteria in the presence of multiple metals.

Marine environments are a repository for metals, and humans have enhanced this phenomenon over the years. Heavy metals are notoriously toxic due to their ability to biomagnify in the food chain and interact with cellular components. Nevertheless, some bacteria have physiological mechanisms that enable them to survive in impacted environments. This characteristic makes them important as biotechnological tools for environmental remediation. Thus, we isolated a bacterial consortium in Guanabara Bay (Brazil), a place with a long metal pollution history. To test the growth efficiency of this consortium in Cu-Zn-Pb-Ni-Cd medium, we measured the activity of key enzymes of microbial activity (esterases and dehydrogenase) under acidic (4.0) and neutral pH conditions, as well as the number of living cells, biopolymer production, and changes in microbial composition during metal exposure. Additionally, we calculated the predicted physiology based on microbial taxonomy. During the assay, a slight modification in bacterial composition was observed, with low abundance changes and little production of carbohydrates. Oceanobacillus chironomi, Halolactibacillus miurensis, and Alkaliphilus oremlandii were predominant in pH 7, despite O. chironomi and Tissierella creatinophila in pH 4, and T. creatinophila in Cu-Zn-Pb-Ni-Cd treatment. The metabolism represented by esterases and dehydrogenase enzymes suggested bacterial investment in esterases to capture nutrients and meet the energy demand in an environment with metal stress. Their metabolism potentially shifted to chemoheterotrophy and recycling nitrogenous compounds. Moreover, concomitantly, bacteria produced more lipids and proteins, suggesting extracellular polymeric substance production and growth in a metal-stressed environment. The isolated consortium showed promise for bioremediation of multimetal contamination and could be a valuable tool in future bioremediation programs.

Cytogenetic aspects of a canine breast carcinosarcoma - a case report.

This study searched a rare and aggressive type of cancer in dogs and humans, the breast carcinosarcoma. Both clinical and pathological traits of mammary carcinosarcomas in dogs are similar to humans, such as infrequent occurrence, fast tumor growth, and unfavorable prognosis when compared to carcinomas. Other possible alterations include chromosomal abnormalities that can be useful for the identification of tumoral cells and diagnosis. The aim of this study was to compare the chromosomal features of peripheral lymphocytes and tumor cells in a mammary carcinosarcoma of a 14-year-old female Poodle. Chromosomes were analyzed from 210 metaphases by conventional Giemsa staining, C-banding, and base-specific fluorochrome staining with chromomycin A3 (CMA3+) and DAPI. Of the 105 blood cells, 56.3% followed the standard karyotype of dogs (2n = 78). In contrast, the carcinosarcoma cells showed high chromosomal numbers (104 to 153), divided into 80% hypertriploid (118 to 136 chromosomes), 10.5% hypotetraploid (137 to 153 chromosomes), 5.7% hypotriploid (104 to 116 chromosomes), and 3.8% triploid cells (117 chromosomes). Among the aneuploid cells identified, we highlighted the trisomy of pair 1 and X chromosome once these elements were easily recognized in karyotype because of their size (pair 1) or differential morphology. Heterochromatin in normal cells was restricted to the pericentromeric region of all chromosomes while few C-bands were observed in tumor cells. This apparent loss of heterochromatin in neoplastic cells was supposed to favor centric fusion among formerly acrocentric chromosomes. Fluorochrome staining reinforced this hypothesis once GC-rich segments (CMA3+) were identified on 10 chromosomes from normal cells (2n = 78) whereas carcinosarcoma metaphases had up to 11 chromosomes bearing CMA3 signals in spite of their remarkable high chromosomal numbers. We concluded that, like in humans, the carcinosarcoma in dogs caused genome instability that eventually led to structural and numerical chromosomal aberrations. Besides, this study reinforced the importance of cytogenetic studies in dogs as a reference material for human cancer studies, especially in rare cases, since it is possible to increase knowledge about the characteristics of breast neoplasms in which there is a little availability of similar cases for comparative studies.

Direct preparation protocol to obtain mitotic chromosomes from canine mammary tumors.

Currently, mammary neoplasms in female canines are a serious problem in veterinary clinics. In addition, the canine species is an excellent disease model for human oncology because of the biological and genetic similarities between the species. Cytogenetics has allowed further study of the characterization of neoplasms in canines. We hypothesized that the use of a direct preparation protocol for mitotic chromosome analysis would provide a simple and low cost protocol for use in all laboratories. The objective of this method is to display in a few hours of dividing cells just like the time of collection since cell division in tissue can be obtained. Ten female canines with the spontaneous occurrence of mammary neoplasia were used to test a pioneering direct preparation protocol to obtain mitotic chromosomes. The excised breast tumor tissue fragments were subjected to the protocol consisting of treatment with colchicine, treatment with hypotonic solution, and fixation. Mitotic chromosomes were absent in cell suspensions of only two samples among the 10 materials analyzed, based on the analysis of five blades for each preparation obtained. So, the cell suspension obtained allowed for the observation of eight tissue samples viable for cytogenetic analysis, five of which had excellent numbers of mitotic chromosomes. However, the technique was unsuccessful in producing high-quality cell suspensions because of inadequate condensation and scattering of chromosomes. While adjustments to methodological procedures are needed, this protocol represents a low cost and simplified method to study the cytogenetics of canine tumors.

Population divergence and peculiar karyoevolutionary trends in the loricariid fish Hypostomus aff. unae from northeastern Brazil.

Loricariidae (Siluriformes, Hypostominae) is one of the most diverse catfish families. In spite of the wide distribution of loricariids in South America, cytogenetic reports are available for only a few species, mostly from southern and southeastern Brazil. We made the first chromosomal analysis of Hypostomus aff. unae from the Contas River basin in northeastern Brazil. Four populations isolated by short distances but from distinct landscapes were studied based on conventional staining, C-banding, argyrophilic nucleolar organizer regions (Ag-NOR), CMA(3)/DAPI fluorochrome staining, and fluorescent in situ hybridization with 18S rDNA probes. Although sharing the same diploid number (2n = 76) and NOR locations, each population presented exclusive karyotype formulae and specific patterns of heterochromatic and AT-rich regions. The derived karyotypes of H. aff. unae (2n >54; high number of acrocentrics bearing AT-rich interstitial heterochromatin) indicated a divergent karyoevolution, mostly driven by centric fissions, pericentric inversions and particular heterochromatin dispersion models. This finding of distinct evolutionary units in H. aff. unae will be useful for understanding the natural history of loricariids from relatively unexplored coastal basins in South America.

Heterochromatin heterogeneity in Hypostomus prope unae (Steindachner, 1878) (Siluriformes, Loricariidae)from Northeastern Brazil.

Cytogenetic analyses using C-banding and chromosomal digestion by several restriction enzymes were carried out in four populations (named A, B, C and D) of Hypostomus prope unae (Loricariidae, Hypostominae) from Contas river basin, northeastern Brazil. These populations share 2n=76 and single NORs on the second metacentric pair but exclusive karyotype forms for each locality. Populations A and B presented conspicuous terminal and interstitial heterochromatic blocks on most of acrocentric chromosomes and equivalent to NORs with differences in both position and bearing pair. Population D showed evident marks at interstitial regions and interspersed with nucleolar region while population C presented interstitial and terminal heterochromatin segments, non-coincident with NORs. The banding pattern after digestion with the endonucleases Alu I, Bam HI, Hae III and Dde I revealed a remarkable heterogeneity within heterochromatin, allowing the identification of distinctive clusters of repeated DNA in the studied populations, besides specific patterns along euchromatic regions. The analysis using restriction enzymes has proved to be highly informative, characterizing population differences and peculiarities in the genome organization of Hypostomus prope unae.