Scielo RSS <![CDATA[Biological Research]]> http://www.scielo.cl/rss.php?pid=0716-976020170001&lang=pt vol. 50 num. lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.cl/img/en/fbpelogp.gif http://www.scielo.cl <![CDATA[Musk gland seasonal development and musk secretion are regulated by the testis in muskrat (<em>Ondatra zibethicus</em>)]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100201&lng=pt&nrm=iso&tlng=pt Abstract Background The muskrat is a seasonal breeder. Males secrete musk to attract females during the breeding season. The testosterone binding to the androgen receptor (AR) in musk glands of muskrat may play an important role conducting the musk secretion process. Methods The musk gland, testis and blood samples of musk rats are collected in both breeding and non-breeding seasons. Some part of the samples are kept in liquid nitrogen for transcriptome analysis and Western blotting test. Some part of the samples are kept in 70% alcohol for histology experiment, blood samples are kept at −20 °C for the serum testosterone measurement experiment. Results This study demonstrates that the quantity of secreted musk, the volume of the musk glands, the diameter of the gland cells and AR expression are all higher during the breeding season than at other times (p &lt; 0.01). StAR, P450scc and 3β-HSD expression in the Leydig cells of the testis were also higher during this season, as was serum testosterone. AR was also observed in the gland cells of two other musk-secreting animals, the musk deer and small Indian civet, in their musk glands. These results suggest that the testes and musk glands co-develop seasonally. Conclusion The musk glands’ seasonal development and musk secretion are regulated by the testes, and testosterone plays an important role in the seasonal development of musk glands. <![CDATA[BJ-1108, a 6-Amino-2,4,5-trimethylpyridin-3-ol analogue, regulates differentiation of Th1 and Th17 cells to ameliorate experimental autoimmune encephalomyelitis]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100202&lng=pt&nrm=iso&tlng=pt Abstract Background CD4+ T cells play an important role in the initiation of an immune response by providing help to other cells. Among the helper T subsets, interferon-γ (IFN-γ)-secreting T helper 1 (Th1) and IL-17-secreting T helper 17 (Th17) cells are indispensable for clearance of intracellular as well as extracellular pathogens. However, Th1 and Th17 cells are also associated with pathogenesis and contribute to the progression of multiple inflammatory conditions and autoimmune diseases. Results In the current study, we found that BJ-1108, a 6-aminopyridin-3-ol analogue, significantly inhibited Th1 and Th17 differentiation in vitro in a concentration-dependent manner, with no effect on proliferation or apoptosis of activated T cells. Moreover, BJ-1108 inhibited differentiation of Th1 and Th17 cells in ovalbumin (OVA)-specific OT II mice. A complete Freund’s adjuvant (CFA)/OVA-induced inflammatory model revealed that BJ-1108 can reduce generation of proinflammatory Th1 and Th17 cells. Furthermore, in vivo studies showed that BJ-1108 delayed onset of disease and suppressed experimental autoimmune encephalomyelitis (EAE) disease progression by inhibiting differentiation of Th1 and Th17 cells. Conclusions BJ-1108 treatment ameliorates inflammation and EAE by inhibiting Th1 and Th17 cells differentiation. Our findings suggest that BJ-1108 is a promising novel therapeutic agent for the treatment of inflammation and autoimmune disease. <![CDATA[Metabotropic glutamate receptor 5 may be involved in macrophage plasticity]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100203&lng=pt&nrm=iso&tlng=pt Abstract Background Macrophages are a functionally heterogeneous cell population and depending on microenvironments they polarize in two main groups: M1 and M2. Glutamic acid and glutamate receptors may participate in the regulation of macrophage plasticity. To investigate the role of glutamatergic systems in macrophages physiology, we performed the transfection of mGluR5 cDNAs into RAW-264.7 cells. Results Comparative analysis of modified (RAW-mGluR5 macrophages) and non-modified macrophages (RAW-macrophages) has shown that the RAW-mGluR5 macrophages absorbed more glutamate than control cells and the amount of intracellular glutamate correlated with the expression of excitatory amino acid transporters -2 (EAAT-2). Besides, our results have shown that RAW-mGluR5 macrophages expressed a higher level of peroxisome proliferator-activated receptor γ (PPAR-γ) and secreted more IL-10, high mobility group box 1 proteins (HMGB1) and Galectin-3 than control RAW-macrophages. Conclusions We propose that elevation of intracellular glutamate and expression of mGluR5 may initiate the metabolic rearrangement in macrophages that could contribute to the formation of an immunosuppressive phenotype. <![CDATA[Analysis of gene expression changes associated with human carcinoma-associated fibroblasts in non-small cell lung carcinoma]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100204&lng=pt&nrm=iso&tlng=pt Abstract Background This study aimed to investigate the gene expression changes associated with carcinoma-associated fibroblasts (CAFs) involving in non-small cell lung carcinoma (NSCLC). Methods We downloaded the GEO series GSE22862, which contained matched gene expression values for 15 CAF and normal fibroblasts samples, and series GSE27289 containing SNP genotyping for four matched NSCLC samples. The differentially expressed genes in CAF samples were identified using the limma package in R. Then we performed gene ontology (GO) and pathway enrichment analysis and protein–protein interaction (PPI) network construction using the identified DEGs. Moreover, aberrant cell fraction, ploidy, allele-specific copy number, and loss of heterozygosity (LOH) within CAF cells were analyzed using the allele-specific copy number analysis. Results We obtained 545 differentially expressed genes between CAF and normal fibroblasts samples. The up-regulated genes are mainly involved in GO terms such as positive regulation of cell migration and extracellular region, while the down-regulated genes participate in the lung development and extracellular region. Multiple genes including bone morphogenetic protein 4 (BMP4) and transforming growth factor, beta 3 (TGFB3) are involved in the TGF-β signaling pathway. Genes including BMP4, TGFBI and matrix Gla protein (MGP) were hub genes. Moreover, no LOH event for BMP4 and MGP was found, that for sphingosine kinase 1 (SPHK1) was 70%, and for TGFBI was 40%. Conclusion Our data suggested that BMP4, MGP, TGFBI, and SPHK1 may be important in CAFs-associated NSCLC, and the abnormal expression and high LOH frequency of them may be used as the diagnosis targets of CAFs in NSCLC. <![CDATA[Uptake of DNA by cancer cells without a transfection reagent]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100205&lng=pt&nrm=iso&tlng=pt Abstract Background Cancer cells exhibit elevated levels of glucose uptake and may obtain pre-formed, diet-derived fatty acids from the bloodstream to boost their rapid growth; they may also use nucleic acid from their microenvironment. The study of processing nucleic acid by cancer cells will help improve the understanding of the metabolism of cancer. DNA is commonly packaged into a viral or lipid particle to be transferred into cells; this process is called transfection in laboratory. Cancer cells are known for having gene mutations and the evolving ability of endocytosis. Their uptake of DNAs might be different from normal cells; they may take in DNAs directly from the environment. In this report, we studied the uptake of DNAs in cancer cells without a transfection reagent. Methods A group of DNA fragments were prepared with PCR and labeled with isotope phosphorous-32 to test their uptake by Huh 7 (liver cancer) and THLE3 (normal liver cells) after incubation overnight by counting radioactivity of the cells’ genomic DNA. Multiple cell lines including breast cancer and lung cancer were tested with the same method. DNA molecules were also labeled with fluorescence to test the location in the cells using a kit of “label it fluorescence in situ hybridization (FISH)” from Mirus (USA). Results The data demonstrated that hepatocellular carcinoma cells possess the ability to take in large DNA fragments directly without a transfection reagent whereas normal liver cells cannot. Huh7 and MDA-MB231 cells displayed a significantly higher Rhodamine density in the cytoplasmic phagosomes and this suggests that the mechanism of uptake of large DNA by cancer cells is likely endocytosis. The efficacy of uptake is related to the DNA’s size. Some cell lines of lung cancer and breast cancer also showed similar uptake of DNA. Conclusions In the present study, we have revealed the evidence that some cancer cells, but not nontumorigenic cells, can take DNA fragments directly from the environment without the aid of the transfecting reagent. <![CDATA[<em>Alpinia oxyphylla</em> Miq. extract changes miRNA expression profiles in db-/db- mouse kidney]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100206&lng=pt&nrm=iso&tlng=pt Abstract Background A number of dysregulated miRNAs have been identified and are proposed to have significant roles in the pathogenesis of type 2 diabetes mellitus or renal pathology. Alpinia oxyphylla has shown significant anti-inflammatory properties and play an anti-diabetes role. The objective of this study was to detect the alteration of miRNAs underlying the anti-diabetes effects of A. oxyphylla extract (AOE) in a type II diabetic animal model (C57BIKsj db-/db-). Results Treatment with AOE for 8 weeks led to lower concentrations of blood glucose, urine albumin, and urine creatinine. 17 and 13 miRNAs were statistically identified as differentially regulated in the DB/DB and db-/db- AOE mice, respectively, compared to the untreated db-/db- mice. Of these, 7 miRNAs were identified in both comparison groups, and these 7 miRNAs were verified by quantitative real-time PCR. Functional bioinformatics showed that the putative target genes of 7 miRNAs were associated with several diabetes effects and signaling pathways. Conclusions These founding suggest that the potential of AOE as a medicinal anti-diabetes treatment through changes in the expressions of specific miRNAs. The results provide a useful resource for future investigation of the role of AOE-regulated miRNAs in diabetes mellitus. <![CDATA[Morphological, molecular and FTIR spectroscopic analysis during the differentiation of kidney cells from pluripotent stem cells]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100207&lng=pt&nrm=iso&tlng=pt Abstract Background Kidney diseases are a global health problem. Currently, over 2 million people require dialysis or transplant which are associated with high morbidity and mortality; therefore, new researches focused on regenerative medicine have been developed, including the use of stem cells. Results In this research, we generate differentiated kidney cells (DKCs) from mouse pluripotent stem cells (mPSCs) analyzing their morphological, genetic, phenotypic, and spectroscopic characteristics along differentiation, highlighting that there are no reports of the use of Fourier transform infrared (FTIR) spectroscopy to characterize the directed differentiation of mPSCs to DKCs. The genetic and protein experiments proved the obtention of DKCs that passed through the chronological stages of embryonic kidney development. Regarding vibrational spectroscopy analysis by FTIR, bands related with biomolecules were shown on mPSCs and DKCs spectra, observing distinct differences between cell lineages and maturation stages. The second derivative of DKCs spectra showed changes in the protein bands compared to mPSCs. Finally, the principal components analysis obtained from FTIR spectra allowed to characterize chemical and structurally mPSCs and their differentiation process to DKCs in a rapid and non-invasive way. Conclusion Our results indicated that we obtained DKCs from mPSCs, which passed through the chronological stages of embryonic kidney development. Moreover, FTIR spectroscopy resulted in a non-invasive, rapid and precise technic that together with principal component analysis allows to characterize chemical and structurally both kind of cells and also discriminate and determine different stages along the cell differentiation process. <![CDATA[Proton NMR characterization of intact primary and metastatic melanoma cells in 2D & 3D cultures]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100208&lng=pt&nrm=iso&tlng=pt Abstract Objective To characterize the differences between the primary and metastatic melanoma cell lines grown in 2D cultures and 3D cultures. Methods Primary melanoma cells (WM115) and metastatic melanoma cells (WM266) extracted from a single donor was cultured in 2D as well as 3D cultures. These cells were characterized using proton NMR spectrometry, and the qualitative chemical shifts markers were identified and discussed. Results In monolayer culture (2D), we observed one qualitative chemical shift marker for primary melanoma cells. In spheroid cultures (3D), we observed nine significant chemical shifts, of which eight markers were specific for primary melanoma spheroids, whereas the other one marker was specific to metastatic melanoma spheroids. This study suggests that the glucose accumulation and phospholipid composition vary significantly between the primary and metastatic cells lines that are obtained from a single donor and also with the cell culturing methods. 14 qualitative chemical shift markers were obtained in the comparison between monolayer culture and spheroids cultures irrespective of the differences in the cell lines. Among which 4 were unique to monolayer cultures whereas 10 chemical shifts were unique to the spheroid cultures. This study also shows that the method of cell culture would drastically affect the phospholipid composition of the cells and also depicts that the cells in spheroid culture closely resembles the cells in vivo. Conclusion This study shows the high specificity of proton NMR spectrometry in characterizing cancer cell lines and also shows the variations in the glucose accumulation and phospholipid composition between the primary and metastatic melanoma cell lines from the same donor. Differences in the cell culture method does plays an important role in phospholipid composition of the cells. <![CDATA[Does <em>Cimicifuga racemosa</em> have the effects like estrogen on the sublingual gland in ovariectomized rats?]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100209&lng=pt&nrm=iso&tlng=pt Abstract Background Cimicifuga racemosa is one of the herbs used for the treatment of climacteric syndrome, and it has been cited as an alternative therapy to estrogen. Apart from hectic fevers, dyspareunia and so on, dry mouth also increase significantly after menopause. It has not yet been reported whether C. racemosa has any impact on the sublingual gland, which may relate to dry mouth. In an attempt to determine this, we have compared the effects of estrogen and C. racemosa on the sublingual gland of ovariectomized rats. Results HE staining showed that the acinar cell area had contracted and that the intercellular spaces were broadened in the OVX (ovariectomized rats) group, while treatment with estradiol (E2) and iCR (isopropanolic extract of C. racemosa) improved these lesions. Transmission electron microscopy showed that rough endoplasmic reticulum expansion in mucous and serous acinar epithelial cells and apoptotic cells was more commonly seen in the OVX group than in the SHAM (sham-operated rats) group. Mitochondria and plasma membrane infolding lesions in the striated ducts were also observed. These lesions were alleviated by both treatments. It is of note that, in the OVX + iCR group, the volume of mitochondria in the striated duct was larger than in other groups. Immunohistochemical staining showed that the ratio of caspase-3 positive cells was significantly increased in the acinar cells of the OVX group compared with the SHAM group (p &lt; 0.05); and the MA (mean absorbance) of caspase-3 in the striated ducts also increased (p &lt; 0.05). Estradiol decreased the ratio of caspase-3 positive cells and the MA of caspase-3 in striated ducts significantly (p &lt; 0.05). ICR also reduced the ratio of caspase-3 positive cells and the MA in the striated ducts (p &lt; 0.05), but the reduction of the MA in striated ducts was inferior to that of the OVX + E2 group (p &lt; 0.05). Conclusion Both estradiol and iCR can inhibit subcellular structural damage, and down-regulate the expression of caspase-3 caused by ovariectomy, but their effects were not identical, suggesting that both drugs confer a protective effect on the sublingual gland of ovariectomized rats, but that the specific location and mechanism of action producing these effects were different. <![CDATA[Knockdown of ubiquitin-specific peptidase 39 inhibited the growth of osteosarcoma cells and induced apoptosis in vitro]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100210&lng=pt&nrm=iso&tlng=pt Abstract Background Ubiquitin specific peptidase 39 (USP39), an essential factor in the assembly of the mature spliceosome complex, has an aberrant expression in several cancer. However, its function and the corresponding mechanism on human osteosarcoma has not been fully explored yet. Methods The mRNA and DNA copies of USP39 were increased in osteosarcoma cancer tissues compared with the one in human normal tissues according to datasets from the publicly available Oncomine database. A further western blot analysis also demonstrated an aberrant endogenous expression of USP39 in three different osteosarcoma cells. Then lentivirus-mediated short hairpin RNA (shRNA) was designed to silence USP39 in human osteosarcoma cell line U2OS, which is used to test the impact of USP39-silencing on cellular proliferation, colony formation, cell cycle distribution and apoptosis. Results Knockdown of USP39 expression in U2OS cell significantly decreased cell proliferation, impaired colony formation ability. A further analysis indicated suppression of USP39 arrested cell cycle progression at G2/M phase via p21 dependent way. In addition, the results of Annexin V/7-AAD staining suggested the knockdown of USP39 could promote U2OS cell apoptosis through PARP cleavage. Conclusions These results uncover the critical role of USP39 in regulating cancer cell mitosis and indicate USP39 is critical for osteosarcoma tumorigenesis. <![CDATA[Expression of cocaine- and amphetamine-regulated transcript (CART) in hen ovary]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100211&lng=pt&nrm=iso&tlng=pt Abstract Background: Cocaine- and amphetamine-regulated transcript (CART), discovered initially by via differential display RT-PCR analysis of brains of rats administered cocaine, is expressed mainly in central nervous system or neuronal origin cells, and is involved in a wide range of behaviors, such as regulation of food intake, energy homeostasis, and reproduction. The hens egg-laying rate mainly depends on the developmental status of follicles, expression of CART have not been identified from hen follicles, the regulatory mechanisms of CART biological activities are still unknown. The objective of this study was to characterize the mRNA expression of CART in hen follicular granulosa cells and determine CART peptide localization and regulatory role during follicular development. Methods: Small white follicles (1–2 mm in diameter) were treated for RNA isolation; Small white follicles (1–2 mm in diameter) and large white follicles (4–6 mm in diameter) were treated for immunohistochemical localization and large white follicles (4–6 mm in diameter), small yellow follicles (6–8 mm in diameter), large yellow follicles (9–12 mm in diameter), mature follicles (F5, F4, F3, F2, F1, &gt;12 mm in diameter) were treated for RNA isolation and Real time PCR. Results: The results showed that full length of the CDS of hen CART was 336 bp encoding a 111 amino acid polypeptide. In the hen ovary, CART peptide was primarily localized to the theca layer, but not all, the oocyte and granulosa layer, with diffused, weaker staining than relative to the theca cell layer. Further, amount of CART mRNA was more (P &lt; 0.05) in granulosa cells of 6–8 mm follicles compared with that in granulosa cells of other follicles. However, CART mRNA amount was greater in theca cells of 4–6 mm follicles relative to follicles of other sizes (P &lt; 0.05). Conclusions: Results suggest that CART could play a potential role in developmental regulation of chicken follicles. <![CDATA[Photosynthesis at the far-red region of the spectrum in <em>Acaryochloris marina</em>]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100212&lng=pt&nrm=iso&tlng=pt Abstract Acaryochloris marina is an oxygenic cyanobacterium that utilizes far–red light for photosynthesis. It has an expanded genome, which helps in its adaptability to the environment, where it can survive on low energy photons. Its major light absorbing pigment is chlorophyll d and it has α–carotene as a major carotenoid. Light harvesting antenna includes the external phycobilin binding proteins, which are hexameric rods made of phycocyanin and allophycocyanins, while the small integral membrane bound chlorophyll binding proteins are also present. There is specific chlorophyll a molecule in both the reaction center of Photosystem I (PSI) and PSII, but majority of the reaction center consists of chlorophyll d. The composition of the PSII reaction center is debatable especially the role and position of chlorophyll a in it. Here we discuss the photosystems of this bacterium and its related biology. <![CDATA[De novo transcriptome assembly, functional annotation and differential gene expression analysis of juvenile and adult <em>E. fetida</em>, a model oligochaete used in ecotoxicological studies]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100401&lng=pt&nrm=iso&tlng=pt Abstract Background Earthworms are sensitive to toxic chemicals present in the soil and so are useful indicator organisms for soil health. Eisenia fetida are commonly used in ecotoxicological studies; therefore the assembly of a baseline transcriptome is important for subsequent analyses exploring the impact of toxin exposure on genome wide gene expression. Results This paper reports on the de novo transcriptome assembly of E. fetida using Trinity, a freely available software tool. Trinotate was used to carry out functional annotation of the Trinity generated transcriptome file and the transdecoder generated peptide sequence file along with BLASTX, BLASTP and HMMER searches and were loaded into a Sqlite3 database. To identify differentially expressed transcripts; each of the original sequence files were aligned to the de novo assembled transcriptome using Bowtie and then RSEM was used to estimate expression values based on the alignment. EdgeR was used to calculate differential expression between the two conditions, with an FDR corrected P value cut off of 0.001, this returned six significantly differentially expressed genes. Initial BLASTX hits of these putative genes included hits with annelid ferritin and lysozyme proteins, as well as fungal NADH cytochrome b5 reductase and senescence associated proteins. At a cut off of P = 0.01 there were a further 26 differentially expressed genes. Conclusion These data have been made publicly available, and to our knowledge represent the most comprehensive available transcriptome for E. fetida assembled from RNA sequencing data. This provides important groundwork for subsequent ecotoxicogenomic studies exploring the impact of the environment on global gene expression in E. fetida and other earthworm species. <![CDATA[Differential roles for pathogenicity islands SPI-13 and SPI-8 in the interaction of <em>Salmonella</em> Enteritidis and <em>Salmonella</em> Typhi with murine and human macrophages]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100402&lng=pt&nrm=iso&tlng=pt Abstract Background Salmonella pathogenicity island (SPI)-13 is conserved in many serovars of S. enterica, including S. Enteritidis, S. Typhimurium and S. Gallinarum. However, it is absent in typhoid serovars such as S. Typhi and Paratyphi A, which carry SPI-8 at the same genomic location. Because the interaction with macrophages is a critical step in Salmonella pathogenicity, in this study we investigated the role played by SPI-13 and SPI-8 in the interaction of S. Enteritidis and S. Typhi with cultured murine (RAW264.7) and human (THP-1) macrophages. Results Our results showed that SPI-13 was required for internalization of S. Enteritidis in murine but not human macrophages. On the other hand, SPI-8 was not required for the interaction of S. Typhi with human or murine macrophages. Of note, the presence of an intact copy of SPI-13 in a S. Typhi mutant carrying a deletion of SPI-8 did not improve its ability to be internalized by, or survive in human or murine macrophages. Conclusions Altogether, our results point out to different roles for SPI-13 and SPI-8 during Salmonella infection. While SPI-13 contributes to the interaction of S. Enteritidis with murine macrophages, SPI-8 is not required in the interaction of S. Typhi with murine or human macrophages. We hypothesized that typhoid serovars have lost SPI-13 and maintained SPI-8 to improve their fitness during another phase of human infection. <![CDATA[A spleen tyrosine kinase inhibitor attenuates the proliferation and migration of vascular smooth muscle cells]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100403&lng=pt&nrm=iso&tlng=pt Abstract Background Pathologic vascular smooth muscle cell (VSMC) proliferation and migration after vascular injury promotes the development of occlusive vascular disease. Therefore, an effective chemical agent to suppress aberrant proliferation and migration of VSMCs can be a potential therapeutic modality for occlusive vascular disease such as atherosclerosis and restenosis. To find an anti-proliferative chemical agent for VSMCs, we screened an in-house small molecule library, and the selected small molecule was further validated for its anti-proliferative effect on VSMCs using multiple approaches, such as cell proliferation assays, wound healing assays, transwell migration assays, and ex vivo aortic ring assay. Results Among 43 initially screened small molecule inhibitors of kinases that have no known anti-proliferative effect on VSMCs, a spleen tyrosine kinase (Syk) inhibitor (BAY61-3606) showed significant anti-proliferative effect on VSMCs. Further experiments indicated that BAY61 attenuated the VSMC proliferation in both concentration- and time-dependent manner, and it also significantly suppressed the migration of VSMCs as assessed by both wound healing assays and transwell assays. Additionally, BAY61 suppressed the sprouting of VSMCs from endothelium-removed aortic rings. Conclusion The present study identified a Syk kinase inhibitor as a potent VSMC proliferation and migration inhibitor and warrants further studies to elucidate its underlying molecular mechanisms, such as its primary target, and to validate its in vivo efficacy as a therapeutic agent for restenosis and atherosclerosis. <![CDATA[Selective intra-dinucleotide interactions and periodicities of bases separated by K sites: a new vision and tool for phylogeny analyses]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100501&lng=pt&nrm=iso&tlng=pt Abstract Direct tests of the random or non-random distribution of nucleotides on genomes have been devised to test the hypothesis of neutral, nearly-neutral or selective evolution. These tests are based on the direct base distribution and are independent of the functional (coding or non-coding) or structural (repeated or unique sequences) properties of the DNA. The first approach described the longitudinal distribution of bases in tandem repeats under the Bose–Einstein statistics. A huge deviation from randomness was found. A second approach was the study of the base distribution within dinucleotides whose bases were separated by 0, 1, 2… K nucleotides. Again an enormous difference from the random distribution was found with significances out of tables and programs. These test values were periodical and included the 16 dinucleotides. For example a high “positive” (more observed than expected dinucleotides) value, found in dinucleotides whose bases were separated by (3K + 2) sites, was preceded by two smaller “negative” (less observed than expected dinucleotides) values, whose bases were separated by (3K) or (3K + 1) sites. We examined mtDNAs, prokaryote genomes and some eukaryote chromosomes and found that the significant non-random interactions and periodicities were present up to 1000 or more sites of base separation and in human chromosome 21 until separations of more than 10 millions sites. Each nucleotide has its own significant value of its distance to neutrality; this yields 16 hierarchical significances. A three dimensional table with the number of sites of separation between the bases and the 16 significances (the third dimension is the dinucleotide, individual or taxon involved) gives directly an evolutionary state of the analyzed genome that can be used to obtain phylogenies. An example is provided. <![CDATA[Properties of realgar bioleaching using an extremely acidophilic bacterium and its antitumor mechanism as an anticancer agent]]> http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602017000100502&lng=pt&nrm=iso&tlng=pt Abstract Realgar is a naturally occurring arsenic sulfide (or Xionghuang, in Chinese). It contains over 90% tetra-arsenic tetrasulfide (As4S4). Currently, realgar has been confirmed the antitumor activities, both in vitro and in vivo, of realgar extracted using Acidithiobacillus ferrooxidans (A. ferrooxidans). Bioleaching, a new technology to greatly improve the use rate of arsenic extraction from realgar using bacteria, is a novel methodology that addressed a limitation of the traditional method for realgar preparation. The present systematic review reports on the research progress in realgar bioleaching and its antitumor mechanism as an anticancer agent. A total of 93 research articles that report on the biological activity of extracts from realgar using bacteria and its preparation were presented in this review. The realgar bioleaching solution (RBS) works by inducing apoptosis when it is used to treat tumor cells in vitro and in vivo. When it is used to treat animal model organisms in vivo, such as mice and Caenorhabditis elegans, tumor tissues grew more slowly, with mass necrosis. Meanwhile, the agent also showed obvious inhibition of tumor cell growth. Bioleaching technology greatly improves the utilization of realgar and is a novel methodology to improve the traditional method.