Although the use of plant growth-promoting bacteria in agriculture is a reality, the molecular basis of plant-bacterial interaction is still poorly understood. We used a proteomic approach to study the mechanisms of interaction of Herbaspirillum seropedicae SmR1 with rice. Root proteins of rice seedlings inoculated or noninoculated with H. seropedicae were separated by 2-D electrophoresis. Differentially expressed proteins were identified by MALDI-TOF/TOF and MASCOT program. Among the identified proteins of H. seropedicae, the dinitrogenase reductase NifH and glutamine synthetase GlnA, which participate in nitrogen fixation and ammonium assimilation, respectively, were the most abundant. The rice proteins up-regulated included the S-adenosylmethionine synthetase, methylthioribose kinase, and acireductone dioxygenase 1, all of which are involved in the methionine recycling. S-Adenosylmethionine synthetase catalyzes the synthesis of S-adenosylmethionine, an intermediate used in transmethylation reactions and in ethylene, polyamine, and phytosiderophore biosynthesis. RT-qPCR analysis also confirmed that the methionine recycling and phytosiderophore biosynthesis genes were up-regulated, while ACC oxidase mRNA level was down-regulated in rice roots colonized by bacteria. In agreement with these results, ethylene production was reduced approximately three-fold in rice roots colonized by H. seropedicae. The results suggest that H. seropedicae stimulates methionine recycling and phytosiderophore synthesis and diminishes ethylene synthesis in rice roots.

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ABSTRACT. Breast cancer is the second most common cancer worldwide and the first among women. Invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) are the two major histological subtypes, and the clinical and molecular differences between them justify the search for new markers to distinguish them. As proteomic analysis allows for a powerful and analytical approach to identify potential biomarkers, we performed a comparative analysis of IDC and ILC samples by using two-dimensional electrophoresis and mass spectrometry. Twenty-three spots were identified corresponding to 10 proteins differentially expressed between the two subtypes. ACTB, ACTG, TPM3, TBA1A, TBA1B, VIME, TPIS, PDIA3, PDIA6, and VTDB were upregulated in ductal carcinoma compared to in lobular carcinoma samples. Overall, these 10 proteins have a key role in oncogenesis. Their specific functions and relevance in cancer initiation and progression are further discussed in this study. The identified peptides represent promising biomarkers for the differentiation of ductal and lobular breast cancer subtypes, and for future interventions based on tailored therapy.

Galactose oxidase (GO) converts galactose to an aldehyde and has several biotechnological applications, including cancer diagnosis. It is mainly produced by Fusarium austroamericanum but is also produced by Fusarium acuminatum and by isolates of the Fusarium graminearum and Gibberella fujikuroi complexes. The F. austroamericanum GO gaoA gene has been cloned, but the GO genes from other secreting species have not been characterized. Problems associated with the F. austroamericanum GO such as high pI and low catalytic efficiency and thermostability, and the difficult purification process makes the search for homologous genes attractive. In this work, the GO genes from Fusarium verticillioides and Fusarium subglutinans, two species of the G. fujikuroi complex, were cloned, sequenced, and analyzed. New GO genes were found in databases and were used to construct a phylogenetic tree, which revealed the existence of three orthologous lineages of GO genes in Fusarium spp. In addition, RT-PCR analyses revealed that the new GO cloned gene may be endogenously expressed in F. subglutinans but not in F. verticillioides, in the used culture conditions.

Bacterial endophytes of the genus Herbaspirillum colonize sugar cane and can promote plant growth. The molecular mechanisms that mediate plant- H. seropedicae interaction are poorly understood. In this work, we used 2D-PAGE electrophoresis to identify H. seropedicae proteins differentially expressed at the log growth phase in the presence of sugar cane extract. The differentially expressed proteins were validated by RT qPCR. A total of 16 differential spots (1 exclusively expressed, 7 absent, 5 up- and 3 down-regulated) in the presence of 5% sugar cane extract were identified; thus the host extract is able to induce and repress specific genes of H. seropedicae. The differentially expressed proteins suggest that exposure to sugar cane extract induced metabolic changes and adaptations in H. seropedicae presumably in preparation to establish interaction with the plant.