Resumo Poliploides sintéticos são materias fundamentais para melhoramento genético da melancia. Comparativamente ao seu homólogo diploide, a melancia tetraploide apresenta amplas diferenças genotípica e fenotípica e diferença de expressão gênica. A expressão gênica digital ou DGE (digital gene expression) foi utilizada neste estudo para representar o perfil de expressão gênica da melancia autotetraploide e seu progenitor diploide e a expressão diferencial de genes relacionados ao estresse biótico e abiótico. Os resultados mostraram que 4.985 DEGs foram observados no organismo autotetraploide, sendo que, deste total, 66.02%foram supra-regulados. A análise de ontologia gênica (GO) mostrou que estes DEGs estão relacionados principalmente com processos metabólicas, célula e atividade catalítica, abrangendo de acordo com a análise de genes e genoma (KEGG) rotas metabólicas, metabolismo secundário e ribossomos. Além disso, 134 genes de defesa foram identificados, abrangendo substâncias de ajuste osmótico, enzimas/proteínas de proteção, proteínas sinalizadoras e proteínas relacionadas à patogênese. Este estudo mostrou a expressão diferencial de genes relacionados ao estresse e o perfil global de expressão gênica de melancia autotetraploide, estes resultados podem complementar, a nível molecular, o entendimento do fator resistência após a duplicação do genoma em cucurbitáceas.

Abstract Synthetic polyploids are key breeding materials for watermelon. Compared with diploid watermelon, the tetraploid watermelon often exhibit wide phenotypic differences and differential gene expression. Digital gene expression (DGE) profile technique was performed in this study to present gene expression patterns in an autotetraploid and its progenitor diploid watermelon, and deferentially expressed genes (DEGs) related to the abiotic and biotic stress were also addressed. Altogether, 4,985 DEGs were obtained in the autotetraploid against its progenitor diploid, and 66.02% DEGs is up-regulated. GO analysis shows that these DEGs mainly distributed in ‘metabolic process’, ‘cell’ and ‘catalytic activity’. KEGG analysis revealed that these DEGs mainly cover ‘metabolic pathways’, ‘secondary metabolites’ and ‘ribosome’. Moreover, 134 tolerance related DEGs were identified which cover osmotic adjustment substance, protective enzymes/protein, signaling proteins and pathogenesis-related proteins. This study present the differential expression of stress related genes and global gene expression patterns at background level in autotetraploid watermelons. These new evidences could supplement the molecular theoretical basis for the better resistance after the genome doubling in the gourd family.

Red mud is the waste generated during the production of alumina from bauxite. The high-temperature reduction of red mud in the absence and presence of sodium borate was carried out to facilitate the subsequent recovery of iron by wet magnetic separation. Sodium borate was found to enhance the recovery of iron, as well as increasing the particle size of metallic iron significantly. High-temperature reduction in the presence of 4% sodium borate increased the iron grade of the metallic powder to 90.05%, compared to 80.24% without sodium borate under the optimum conditions of roasting at 1300°C for 30 min. Experimental evidence showed that sodium borate promotes the reduction of iron oxides and the growth of metallic iron grains, which leads to improved separation between iron and gangue during the subsequent magnetic separation.

MicroRNAs (miRNAs) are small RNA molecules that modulate gene expression implicated in cancer, which play crucial roles in diverse biological processes, such as development, differentiation, apoptosis, and proliferation. The aim of this study was to investigate whether miR-30c mediated the resistance of breast cancer cells to the chemotherapeutic agent doxorubicin (ADR) by targeting tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ). miR-30c was downregulated in the doxorubicin-resistant human breast cancer cell lines MCF-7/ADR and MDA-MB-231/ADR compared with their parental MCF-7 and MDA-MB-231 cell lines, respectively. Furthermore, we observed that transfection of an miR-30c mimic significantly suppressed the ability of MCF-7/ADR to resist doxorubicin. Moreover, the anti-apoptotic gene YWHAZ was confirmed as a target of miR-30c by luciferase reporter assay, and further studies indicated that the mechanism for miR-30c on the sensitivity of breast cancer cells involved YWHAZ and its downstream p38 mitogen-activated protein kinase (p38MAPK) pathway. Together, our findings provided evidence that miR-30c was one of the important miRNAs in doxorubicin resistance by regulating YWHAZ in the breast cancer cell line MCF-7/ADR.