Representative Members Research Articles

Biomineralization pathways in calcifying dinoflagellates: Uptake, storage in MgCaP-rich bodies and formation of the shell

Little is known about shell formation of calcareous dinoflagellates, despite the fact that they are one of the major calcifying organisms of the phytoplankton. Here, calcitic cyst formation in two representative members of calcareous dinoflagellates is investigated using cryo-electron microscopy (cryo-SEM and cryo-FIB-SEM) in combination with micro-Raman and infrared spectroscopy. Only calcein-AM and not calcein enters these cells, indicating active uptake of calcium and other divalent cations. Multifunctional vacuoles containing crystalline inclusions are observed, and the crystals are identified as anhydrous guanine in the β-form. The same vacuolar enclosures contain dense magnesium-, calcium-, and phosphorous-rich mineral bodies. These bodies are presumably secreted into the outer matrix where calcite forms. Calcite formation occurs via multiple independent nucleation events, and the different crystals grow with preferred orientation into a dense reticular network that forms the mature calcitic shell. We suggest a biomineralization pathway for calcareous dinoflagellates that includes (1) active uptake of calcium through the membranes, (2) deposition of Mg2+- and Ca2+-ions inside disordered MgCaP-rich mineral bodies, (3) secretion of these bodies to the inter-membrane space, and (4) Formation and growth of calcite into a dense reticulate network. This study provides new insights into calcium uptake, storage and transport in calcifying dinoflagellates. Statement of significanceLittle is known about the shell formation of calcareous dinoflagellates, despite the fact that they are one of the major calcifying organisms of the phytoplankton. We used state-of-the-art cryo-electron microscopy (cryo-SEM and cryo-FIB-SEM) in combination with micro-Raman spectroscopy to provide new insights into mineral formation in calcifying dinoflagellates.To date, intracellular crystalline calcite was assumed to be involved in calcite shell formation. Surprisingly, we identify these crystalline inclusions as anhydrous guanine suggesting that they are not involved in biomineralization. Instead, a key finding is that MgCaP-rich bodies are probably secreted into the outer matrix where the calcite shell is formed. We suggest that these bodies are an essential part of Ca-uptake, -storage and –transport and propose a new biomineralization model.

First detection and complete genome of Soybean chlorotic mottle virus naturally infecting soybean in China by deep sequencing

Soybean chlorotic mottle virus (SbCMV) was first detected from soybean plants in Jiangxi Province of China by high throughput sequencing and was confirmed by PCR. The complete nucleotide sequence of NC113 was determined to be 8 210 nucleotides, and shared the highest similarity (91.7%) with sequences of SbCMV that was only reported in Japan. It encodes nine putative open reading frames (ORFs Ia, Ib and II–VIII), and contains a large intergenic region located at nucleotide 5 976–6 512 between ORFs VI and VII. Sequence analysis and phylogenetic tree indicated that NC113 is an isolate of SbCMV, and is more related to the soymoviruses Blueberry red ringspot virus (BRRSV), Peanut chlorotic streak virus (PCSV) and Cestrum yellow leaf curling virus (CmYLCV) than to other representative members in the Caulimoviridae family. Field survey of 472 legume plants from Jiangxi and Zhejiang provinces showed SbCMV was only detected from soybean in Nanchang City with a low incidence rate. This is the first report of Soybean chlorotic mottle virus identified in China.

A Divergent Synthetic Route to the Vallesamidine and Schizozygine Alkaloids: Total Synthesis of (+)-Vallesamidine and (+)-14,15-Dehydrostrempeliopine.

The total synthesis of representative members of the schizozygine alkaloids, (+)-vallesamidine and (+)-14,15-dehydrostrempeliopine, were completed from a late-stage divergent intermediate. The synthesis took advantage of efficient nitro-group reactions with the A/B/C ring skeleton constructed concisely on a gram scale through an asymmetric Michael addition, nitro-Mannich/lactamisation, Tsuji-Trost allylation, and intramolecular C-N coupling reaction. Other key features of the synthesis are a novel [1,4] hydride transfer/Mannich-type cyclisation to build ring E and a diastereoselective ring-closing metathesis reaction to construct ring D. This approach gave access to a late-stage C14,C15 alkene divergent intermediate that could be simply transformed into (+)-vallesamidine, (+)-14,15-dehydrostrempeliopine, and potentially other schizozygine alkaloids and unnatural derivatives.

A Divergent Synthetic Route to the Vallesamidine and Schizozygine Alkaloids: Total Synthesis of (+)‐Vallesamidine and (+)‐14,15‐Dehydrostrempeliopine

AbstractThe total synthesis of representative members of the schizozygine alkaloids, (+)‐vallesamidine and (+)‐14,15‐dehydrostrempeliopine, were completed from a late‐stage divergent intermediate. The synthesis took advantage of efficient nitro‐group reactions with the A/B/C ring skeleton constructed concisely on a gram scale through an asymmetric Michael addition, nitro‐Mannich/lactamisation, Tsuji–Trost allylation, and intramolecular C−N coupling reaction. Other key features of the synthesis are a novel [1,4] hydride transfer/Mannich‐type cyclisation to build ring E and a diastereoselective ring‐closing metathesis reaction to construct ring D. This approach gave access to a late‐stage C14,C15 alkene divergent intermediate that could be simply transformed into (+)‐vallesamidine, (+)‐14,15‐dehydrostrempeliopine, and potentially other schizozygine alkaloids and unnatural derivatives.

Community structure and distribution of benthic Bacteria and Archaea in a stratified coastal lagoon in the Southern Gulf of Mexico

Coastal lagoons are important aquatic systems with strong physicochemical gradients, where the participation of microorganisms in biogeochemical cycles has been well recognised; however, to date, the microbial diversity and distribution in these environments remains under-investigated. Here, three distinguished regions (oligohaline, marine and the mixing) of a transitional coastal lagoon were explored to characterise the structure and composition of benthic microbial communities through 16S rRNA gene Illumina-sequencing, for both Bacteria and Archaea domains. Principal coordinate analysis showed differences in the community structure according to the analysed zones. PERMANOVA analysis evidenced that, of the measured variables, sample zonation and salinity were the main environmental factors explaining the variance of the prokaryotic assemblages. Differentially abundant microbial taxa were detected for each region of the lagoon by LEfSe analysis. Representative members of anaerobic methanogens/methanotrophs (Methanosaetaceae, ANME 1-b and WSA2) were enriched in the oligohaline sediments, while the coastal marine zone had a community represented mainly by Sandaracinaceae, Aminicenantes and Thaumarchaeota (Group-C3). The sediments in the mixing zone had higher abundance of Flavobacteriaceae, Syntrophobacteraceae and uncultured Thermoplasmatales, Bathyarchaeota and Lokiarchaeota. This study expands the available information of the composition and distribution of uncultured Bacteria and Archaea in transitional coastal lagoons, contributing to a systematic understanding of the functioning of these ecosystems.

Evolutionary Trends in RNA Base Selectivity Within the RNase A Superfamily.

There is a growing interest in the pharmaceutical industry to design novel tailored drugs for RNA targeting. The vertebrate-specific RNase A superfamily is nowadays one of the best characterized family of enzymes and comprises proteins involved in host defense with specific cytotoxic and immune-modulatory properties. We observe within the family a structural variability at the substrate-binding site associated to a diversification of biological properties. In this work, we have analyzed the enzyme specificity at the secondary base binding site. Towards this end, we have performed a kinetic characterization of the canonical RNase types together with a molecular dynamic simulation of selected representative family members. The RNases’ catalytic activity and binding interactions have been compared using UpA, UpG and UpI dinucleotides. Our results highlight an evolutionary trend from lower to higher order vertebrates towards an enhanced discrimination power of selectivity for adenine respect to guanine at the secondary base binding site (B2). Interestingly, the shift from guanine to adenine preference is achieved in all the studied family members by equivalent residues through distinct interaction modes. We can identify specific polar and charged side chains that selectively interact with donor or acceptor purine groups. Overall, we observe selective bidentate polar and electrostatic interactions: Asn to N1/N6 and N6/N7 adenine groups in mammals versus Glu/Asp and Arg to N1/N2, N1/O6 and O6/N7 guanine groups in non-mammals. In addition, kinetic and molecular dynamics comparative results on UpG versus UpI emphasize the main contribution of Glu/Asp interactions to N1/N2 group for guanine selectivity in lower order vertebrates. A close inspection at the B2 binding pocket also highlights the principal contribution of the protein ß6 and L4 loop regions. Significant differences in the orientation and extension of the L4 loop could explain how the same residues can participate in alternative binding modes. The analysis suggests that within the RNase A superfamily an evolution pressure has taken place at the B2 secondary binding site to provide novel substrate-recognition patterns. We are confident that a better knowledge of the enzymes’ nucleotide recognition pattern would contribute to identify their physiological substrate and eventually design applied therapies to modulate their biological functions.

Practice pattern of non-muscle invasive bladder cancer in Japan, Korea and Taiwan: A Web-based survey.

To investigate the treatment pattern of non-muscle invasive bladder cancer patients among urologists in Japan, Korea and Taiwan, with emphasis on compliance with important treatment guidelines. A Web-based questionnaire survey was conceived by representative members of each country's urological oncology society and was open from June 2016 to February 2017 to each society's members. Descriptive statistics and multinomial logistic regression analysis were used. A total of 2334 urologists were invited and 701 responded to the survey with a response rate of 30.0%. Instruments used during transurethral resection of bladder cancer varied significantly between countries and depended on their availability. The re-transurethral resection rate for pT1 or high-grade disease >50% of the time was significantly higher in Japan than in the other two countries, but the collective rate was just 49%. The frequency of intravesical therapy in intermediate- to high-risk disease was generally consistent across countries. However, the choice of agent between chemotherapy and bacillus Calmette-Guérin was significantly different between countries. Maintenance bacillus Calmette-Guérin was used <10% of the time by 45% of respondents, the most important reasons being fear of side-effects, followed by a lack of efficacy and shortage of drug supply. There are significant differences between Japan, Korea and Taiwan in the management of intermediate- to high-risk non-muscle invasive bladder cancer. The results of this survey can serve as the basis for joint efforts to develop common clinical guidelines.

Visualizing the Stability of 2D Point Sets from Dimensionality Reduction Techniques

AbstractWe usek‐order Voronoi diagrams to assess the stability ofk‐neighbourhoods in ensembles of 2D point sets, and apply it to analyse the robustness of a dimensionality reduction technique to variations in its input configurations. To measure the stability ofk‐neighbourhoods over the ensemble, we use cells in thek‐order Voronoi diagrams, and consider the smallest coverings of corresponding points in all point sets to identify coherent point subsets with similar neighbourhood relations. We further introduce a pairwise similarity measure for point sets, which is used to select a subset of representative ensemble members via the PageRank algorithm as an indicator of an individual member's value. The stability information is embedded into thek‐order Voronoi diagrams of the representative ensemble members to emphasize coherent point subsets and simultaneously indicate how stable they lie together in all point sets. We use the proposed technique for visualizing the robustness of t‐distributed stochastic neighbour embedding and multi‐dimensional scaling applied to high‐dimensional data in neural network layers and multi‐parameter cloud simulations.

Diversity in the Last Decade of the Association of Program Directors in Surgery: A Descriptive Analysis of Leadership and Future Directions

The Association of Program Directors in Surgery Diversity and Inclusion Taskforce (APDS-DIT) was created in 2017 after the Executive Committee recognized low diversity in its membership. The DIT was charged to address gaps in diversity and inclusion at various phases of training and development from medical student to surgical leader. The aim of this study was to examine APDS demographics and determine the status of inclusion of women, racial and ethnic minorities, and nonuniversity surgeons. Eleven years (2008-2018) of APDS annual-meeting programs, web directory, 2018-membership lists, and 2017-AAMC data were analyzed. Leadership positions were examined by officer (program chair/vice chair, executive committee, and board of directors. Internet searches identified gender, race, and institutional affiliation. Representative members to other organizations, resident liaisons, and historian members were excluded. APDS "Member," "Associate," and "Resident" lists and AAMC data were divided by gender. Fifty-one individuals fulfilled 223 leadership positions over 11 years; 13 (25%) were women and 5 (10%) were non-Caucasian. Since 2013, the percentage of nonuniversity surgeons in APDS leadership has declined while, over the last 2 years, the percentage of women and ethnic/racial minority has increased. In 2018, the percentage of women in leadership (38%) was higher than the percentage of women in membership (combined total of program directors and associate program directors [26%]) and nonuniversity-affiliated surgeons comprised 35% of the APDS membership but only 14% of leadership roles. Over the last 11 years, representation of women, non-Caucasians, and nonuniversity surgeons has been at or less than 1/3 of their counterparts. As an organization that is tasked with creating future generations of the surgical workforce, it is imperative to recognize an under-representation of those members with diverse backgrounds that would add to the creative growth of the organization. The creation of the APDS-DIT emphasizes the organization's commitment to diversity and inclusion and an effort to create a pipeline of diverse leaders in the APDS and surgical training in general.

Biomineralization Pathways in Calcifying Dinoflagellates: Uptake, Storage in MgCaP-Rich Bodies and Formation of the Shell

Little is known about the formation of the shells of calcareous dinoflagellates, despite the fact that they are one of the major calcifying organisms of the phytoplankton. Here, we investigate calcitic cyst formation in two representative members from different clades of calcareous dinoflagellates using cryo-electron microscopy (cryo-SEM and cryo-FIB-SEM) in combination with micro-Raman and infrared spectroscopy.Only calcein-AM and not calcein enters these cells, indicating active uptake of calcium and other divalent cations. Multifunctional vacuoles containing crystalline inclusions are observed in both species and we identify the crystals as anhydrous guanine in the β-form. We also observe in the same vacuolar enclosures, dense magnesium, calcium and phosphorous rich mineral bodies by cryo EDX. These bodies are secreted into the outer matrix space where calcite forms. Calcite formation occurs via multiple independent nucleation events and the different crystals grow with preferred orientation into a dense reticular network that forms the calcitic cyst. The degree of atomic order of this calcite is less than that of geological calcite. We suggest a common biomineralization pathway for these two calcifying dinoflagellates: (1) Uptake of calcium and other cations through the membranes. (2) Deposition of Mg2+ and Ca2+ ions inside a disordered MgCaP-body. (3) Secretion of these bodies to the space between the outer membranes. (4) Formation and growth of calcite bodies into a dense reticulate network that forms the mature calcitic shell. This study provides new insights into calcium uptake, storage and transport in calcifying dinoflagellates.

A55 Molecular systematics of sturgeon nucleocytoplasmic large DNA viruses

Namao virus (NV) is a sturgeon nucleocytoplasmic large DNA virus (sNCLDV) that can cause a lethal disease of the integumentary system in lake sturgeon Acipenser fulvescens. As a group, the sNCLDV have not been assigned to any currently recognized taxonomic family of viruses. In this study, a dataset of NV DNA sequences was generated and assembled as two non-overlapping contigs of 306 and 448 base pairs (bp) and then used to conduct a comprehensive systematics analysis using Bayesian phylogenetic inference for NV, other sNCLDV, and representative members of six families of the NCLDV superfamily. The phylogeny of NV was reconstructed using protein homologues encoded by nine nucleocytoplasmic virus orthologous genes (NCVOGs): NCVOG0022—mcp, NCVOG0038—DNA polymerase B elongation subunit, NCVOG0076—VV A18-type helicase, NCVOG0249—VV A32-type ATPase, NCVOG0262—AL2 VLTF3-like transcription factor, NCVOG0271—RNA polymerase II subunit II, NCVOG0274—RNA polymerase II subunit I, NCVOG0276—ribonucleotide reductase small subunit, and NCVOG1117—mRNA capping enzyme. The accuracy of our phylogenetic method was evaluated using a combination of Bayesian statistical analysis and congruence analysis. Stable tree topologies were obtained with datasets differing in target molecule(s), sequence length, and taxa. Congruent topologies were obtained in phylogenies constructed using individual protein datasets and when four proteins were used in a concatenated approach. The major capsid protein phylogeny indicated that ten representative sNCLDV form a monophyletic group comprised of four lineages within a polyphyletic Mimi-Phycodnaviridae group of taxa. Overall, the analyses revealed that Namao virus is a member of the Mimiviridae family with strong and consistent support for a clade containing NV and CroV as sister taxa.

From Planning to Implementation of the YouthCan IMPACT Project: a Formative Evaluation

In order to improve the youth mental health system, there is an international movement toward developing community-based service hubs that provide integrated, collaborative care to youth. However, the implementation of multisystem collaboration is complex and can be hampered by barriers. This paper presents a formative evaluation of the YouthCan IMPACT integrated youth services project based on the Consolidated Framework for Implementation Research (CFIR), to identify facilitators and barriers to successful implementation. Results highlight that previous positive working relationships along with collaborative investment of resources from partnering organizations are essential to implement an integrated youth service model. In addition, it is important that representative members of all key stakeholder groups, including staff, youth, and caregivers, be involved in the development and execution of the project to ensure effective implementation. Attention to the facilitators and barriers to implementation may help teams seeking to implement highly collaborative, integrated models of service delivery for youth in the community.

Multifunctionality in Two Families of Dinuclear Lanthanide(III) Complexes with a Tridentate Schiff-Base Ligand.

The employment of N-(2-carboxyphenyl)salicylideneimine in 4f metal chemistry has led to two families of dinuclear complexes depending on the lanthanide(III) used. Representative members exhibit interesting magnetic, optical, and catalytic properties.

IR ion spectroscopy in a combined approach with MS/MS and IM-MS to discriminate epimeric anthocyanin glycosides (cyanidin 3-O-glucoside and -galactoside)

Anthocyanins are widespread in plants and flowers, being responsible for their different colouring. Two representative members of this family have been selected, cyanidin 3-O-β-glucopyranoside and 3-O-β-galactopyranoside, and probed by mass spectrometry based methods, testing their performance in discriminating between the two epimers. The native anthocyanins, delivered into the gas phase by electrospray ionization, display a comparable drift time in ion mobility mass spectrometry (IM-MS) and a common fragment, corresponding to loss of the sugar moiety, in their collision induced dissociation (CID) pattern. However, the IR multiple photon dissociation (IRMPD) spectra in the fingerprint range show a feature particularly evident in the case of the glucoside. This signature is used to identify the presence of cyanidin 3-O-β-glucopyranoside in a natural extract of pomegranate. In an effort to increase any differentiation between the two epimers, aluminum complexes were prepared and sampled for elemental composition by FT-ICR-MS. CID experiments now display an extensive fragmentation pattern, showing few product ions peculiar to each species. More noteworthy is the IRMPD behavior in the OH stretching range showing significant differences in the spectra of the two epimers. DFT calculations allow to interpret the observed distinct bands due to a varied network of hydrogen bonding and relative conformer stability.

State-of-the-art CRISPR/Cas9 Technology for Genome Editing in Trypanosomatids.

CRISPR/Cas9 technology has revolutionized biology. This prokaryotic defense system against foreign DNA has been repurposed for genome editing in a broad range of cell tissues and organisms. Trypanosomatids are flagellated protozoa belonging to the order Kinetoplastida. Some of its most representative members cause important human diseases affecting millions of people worldwide, such as Chagas disease, sleeping sickness and different forms of leishmaniases. Trypanosomatid infections represent an enormous burden for public health and there are no effective treatments for most of the diseases they cause. Since the emergence of the CRISPR/Cas9 technology, the genetic manipulation of these parasites has notably improved. As a consequence, genome editing is now playing a key role in the functional study of proteins, in the characterization of metabolic pathways, in the validation of alternative targets for antiparasitic interventions, and in the study of parasite biology and pathogenesis. In this work we review the different strategies that have been used to adapt the CRISPR/Cas9 system to Trypanosoma cruzi, Trypanosoma brucei, and Leishmania spp., as well as the research progress achieved using these approaches. Thereby, we will present the state-of-the-art molecular tools available for genome editing in trypanosomatids to finally point out the future perspectives in the field.

Chemical logic of MraY inhibition by antibacterial nucleoside natural products

Novel antibacterial agents are needed to address the emergence of global antibiotic resistance. MraY is a promising candidate for antibiotic development because it is the target of five classes of naturally occurring nucleoside inhibitors with potent antibacterial activity. Although these natural products share a common uridine moiety, their core structures vary substantially and they exhibit different activity profiles. An incomplete understanding of the structural and mechanistic basis of MraY inhibition has hindered the translation of these compounds to the clinic. Here we present crystal structures of MraY in complex with representative members of the liposidomycin/caprazamycin, capuramycin, and mureidomycin classes of nucleoside inhibitors. Our structures reveal cryptic druggable hot spots in the shallow inhibitor binding site of MraY that were not previously appreciated. Structural analyses of nucleoside inhibitor binding provide insights into the chemical logic of MraY inhibition, which can guide novel approaches to MraY-targeted antibiotic design.

SynMyco transposon: engineering transposon vectors for efficient transformation of minimal genomes.

Mycoplasmas are important model organisms for Systems and Synthetic Biology, and are pathogenic to a wide variety of species. Despite their relevance, many of the tools established for genome editing in other microorganisms are not available for Mycoplasmas. The Tn4001 transposon is the reference tool to work with these bacteria, but the transformation efficiencies (TEs) reported for the different species vary substantially. Here, we explore the mechanisms underlying these differences in four Mycoplasma species, Mycoplasma agalactiae, Mycoplasma feriruminatoris, Mycoplasma gallisepticum and Mycoplasma pneumoniae, selected for being representative members of each cluster of the Mycoplasma genus. We found that regulatory regions (RRs) driving the expression of the transposase and the antibiotic resistance marker have a major impact on the TEs. We then designed a synthetic RR termed SynMyco RR to control the expression of the key transposon vector elements. Using this synthetic RR, we were able to increase the TE for M. gallisepticum, M. feriruminatoris and M. agalactiae by 30-, 980- and 1036-fold, respectively. Finally, to illustrate the potential of this new transposon, we performed the first essentiality study in M. agalactiae, basing our study on more than 199,000 genome insertions.

Plastid genome evolution in tribe Desmodieae (Fabaceae: Papilionoideae).

Recent plastid genome (plastome) studies of legumes (family Fabaceae) have shown that this family has undergone multiple atypical plastome evolutions from each of the major clades. The tribe Desmodieae belongs to the Phaseoloids, an important but systematically puzzling clade within Fabaceae. In this study, we investigated the plastome evolution of Desmodieae and analyzed its phylogenetic signaling. We sequenced six complete plastomes from representative members of Desmodieae and from its putative sister Phaseoloid genus Mucuna. Those genomes contain 128 genes and range in size from 148,450 to 153,826 bp. Analyses of gene and intron content revealed similar characters among the members of Desmodieae and Mucuna. However, there were also several distinct characters identified. The loss of the rpl2 intron was a feature shared between Desmodieae and Mucuna, whereas the loss of the rps12 intron was specific to Desmodieae. Likewise, gene loss of rps16 was observed in Mucuna but not in Desmodieae. Substantial sequence variation of ycf4 was detected from all the sequenced plastomes, but pseudogenization was restricted to the genus Desmodium. Comparative analysis of gene order revealed a distinct plastome conformation of Desmodieae compared with other Phaseoloid legumes, i.e., an inversion of an approximately 1.5-kb gene cluster (trnD-GUC, trnY-GUA, and trnE-UUC). The inversion breakpoint suggests that this event was mediated by the recombination of an 11-bp repeat motif. A phylogenetic analysis based on the plastome-scale data set found the tribe Desmodieae is a highly supported monophyletic group nested within the paraphyletic Phaseoleae, as has been found in previous phylogenetic studies. Two subtribes (Desmodiinae and Lespedezinae) of Desmodieae were also supported as monophyletic groups. Within the subtribe Lespedezinae, Lespedeza is closer to Kummerowia than Campylotropis.

A Survey on Cooperative Co-Evolutionary Algorithms

The first cooperative co-evolutionary algorithm (CCEA) was proposed by Potter and De Jong in 1994 and since then many CCEAs have been proposed and successfully applied to solving various complex optimization problems. In applying CCEAs, the complex optimization problem is decomposed into multiple subproblems, and each subproblem is solved with a separate subpopulation, evolved by an individual evolutionary algorithm (EA). Through cooperative co-evolution of multiple EA subpopulations, a complete problem solution is acquired by assembling the representative members from each subpopulation. The underlying divide-and-conquer and collaboration mechanisms enable CCEAs to tackle complex optimization problems efficiently, and hence CCEAs have been attracting wide attention in the EA community. This paper presents a comprehensive survey of these CCEAs, covering problem decomposition, collaborator selection, individual fitness evaluation, subproblem resource allocation, implementations, benchmark test problems, control parameters, theoretical analyses, and applications. The unsolved challenges and potential directions for their solutions are discussed.

Sequence diverse miRNAs converge to induce mesenchymal-to-epithelial transition in ovarian cancer cells through direct and indirect regulatory controls.

Epithelial-to-mesenchymal transition (EMT) has been shown to be similarly regulated by multiple miRNAs, some displaying little or no sequence identity. While alternate models have been proposed to explain the functional convergence of sequence divergent miRNAs, little experimental evidence exists to elucidate the underlying mechanisms involved. Representative members of the miR-200 family of miRNAs and the sequence divergent miR-205 miRNA were independently over expressed in mesenchymal-like ovarian cancer (OC) cells resulting in mesenchymal-to-epithelial transition (MET). The miR-205 and the miR-200 family of miRNAs were found to coordinately induce MET in mesenchymal-like OC cells by affecting both direct and indirect changes in the expression of genes previously associated with EMT/MET. Only two direct targets of these miRNAs (ZEB 1 and WNT5A) are commonly down regulated in response to over-expression of miR-205 and/or the miR-200 family of miRNAs. Down-regulation of these genes, alone or in combination, only partially recapitulates the changes induced by the miRNAs indicating an additional contribution of indirect changes regulated by the miRNAs. Combined gene expression analyses and phylogenetic comparisons suggest an evolutionarily more recent involvement of miR-205 in the EMT/MET process.