Analysis of the Promoter of Emb5 from Zea mays Identifies a Region of 523 bp Responsible for Its Embryo-Specific Activity

The maize Emb5 is an abscisic acid–responsive gene which is specifically expressed in the late embryo during seed maturity. To further dissect and identify the elements specific for its embryo expression pattern, we investigated the activity of the − 1653 bp upstream of the “full-length” promoter region of this gene in transgenic Arabidopsis plants. We first confirmed that the “full-length” promoter could indeed drive the expression of β-glucuronidase reporter gene (GUS) in the transgenic Arabidopsis seed embryo. Subsequently, DNA fragments of ~ 500 bp in length were generated after a series of progressive deletions from positions − 1653 bp to − 1 bp relative to the transcriptional initiation site. These fragments were fused with GUS and introduced into Arabidopsis. Measurement of the GUS activity in the immature seeds isolated from the transgenic plants revealed that the region between positions − 523 bp and − 1 bp, namely ProEm-D, is absolutely required and sufficient for the temporal and embryo-specific expression of GUS with an activity comparable with the full-length Emb5 promoter in Arabidopsis. Therefore, our results clearly demonstrated that the 523 bp ProEm-D can replace the − 1653 bp Emb5 promoter to drive embryo-specific expression in Arabidopsis seed. Because of its small size and strong embryo-specific activity, it could become the promoter of choice in metabolic pathway engineering to transfer multiple genes for the production of valuable pharmaceutical products in seeds, such as polyunsaturated fatty acids found in fish oils, or pro-vitamin A where at least three transgenes are required to assemble the entire metabolic pathways

Functional analysis of virulence potential from Gardnerella vaginalis and other anaerobes commonly associated with Bacterial vaginosis

In the past half century, bacterial vaginosis (BV) has been a controversial topic in medical microbiology, and despite the wealth of information on this topic, the etiological agent has not yet been definitively identified Taking these data into consideration, we hypothesized that strains of G. vaginalis that were able to form biofilms could be the causative agent of BV. To test our hypothesis, we isolated more than 30 bacterial species from BV patients and also several strains of G. vaginalis from healthy women, and tested biofilm forming ability, initial adhesion to human vaginal cells, cytotoxicity activity, antimicrobial resistance and gene expression of know virulent genes. Our results revealed that G. vaginalis outcompeted all the other bacterial species in the initial adhesion to the epithelial cells. Furthermore, when comparing BV-associated G. vaginalis strains to strains isolated from healthy women, we found that all 7strains from BV were more virulent than the 7 strains colonizing healthy women, as measured by the higher cytotoxicity and the higher initial adhesion to epithelial cells. No significant differences were found in antimicrobial resistance profiles. Interestingly, no significant differences in expression of known virulence genes were detected, suggesting that the higher virulence of the BV-associated G. vaginalis was due to a yet unknown virulence determinant. We then tested virulent G. vaginalis against other known BV-associated anaerobe pathogens, namely Mobiluncus mulieris, Atopobium vaginae, Prevotella bivia and Fusobacteria nucleatum in mixed biofilm formation quantification. Interestingly, while the other tested anaerobes did not reveal a higher initial adhesion, they did enhance biofilm formation by G. vaginalis. Overall, our data suggests that virulent variants of G. vaginalis have the potential to be the etiological agent of BV, while acknowledging that other anaerobes do enhance G. vaginalis virulence