Flavonols improve tomato pollen thermotolerance during germination and tube elongation by maintaining reactive oxygen species homeostasis.

Elevated temperatures impair pollen performance and reproductive success, resulting in lower crop yields. The tomato (Solanum lycopersicum) anthocyanin reduced (are) mutant harbors a mutation in FLAVANONE 3-HYDROXYLASE (F3H), resulting in impaired flavonol antioxidant biosynthesis. The are mutant has reduced pollen performance and seed set relative to the VF36 parental line, phenotypes that are accentuated at elevated temperatures. Transformation of are with the wild-type F3H gene, or chemical complementation with flavonols, prevented temperature-dependent reactive oxygen species (ROS) accumulation in pollen and restored the reduced viability, germination, and tube elongation of are to VF36 levels. Overexpression of F3H in VF36 prevented temperature-driven ROS increases and impaired pollen performance, revealing that flavonol biosynthesis promotes thermotolerance. Although stigmas of are had reduced flavonol and elevated ROS levels, the growth of are pollen tubes was similarly impaired in both are and VF36 pistils. RNA-seq was performed at optimal and stress temperatures in are, VF36, and the F3H overexpression line at multiple timepoints across pollen tube elongation. The number of differentially expressed genes increased over time under elevated temperatures in all genotypes, with the greatest number in are. These findings suggest potential agricultural interventions to combat the negative effects of heat-induced ROS in pollen that lead to reproductive failure.

Functional recovery following traumatic brain injury in rats is enhanced by oral supplementation with bovine thymus extract.

Traumatic brain injury (TBI) is one of the leading causes of death worldwide. There are currently no effective treatments for TBI, and trauma survivors suffer from a variety of long-lasting health consequences. With nutritional support recently emerging as a vital step in improving TBI patients' outcomes, we sought to evaluate the potential therapeutic benefits of nutritional supplements derived from bovine thymus gland, which can deliver a variety of nutrients and bioactive molecules. In a rat model of controlled cortical impact (CCI), we determined that animals supplemented with a nuclear fraction of bovine thymus (TNF) display greatly improved performance on beam balance and spatial memory tests following CCI. Using RNA-Seq, we identified an array of signaling pathways that are modulated by TNF supplementation in rat hippocampus, including those involved in the process of autophagy. We further show that bovine thymus-derived extracts contain antigens found in neural tissues and that supplementation of rats with thymus extracts induces production of serum IgG antibodies against neuronal and glial antigens, which may explain the enhanced animal recovery following CCI through possible oral tolerance mechanism. Collectively, our data demonstrate, for the first time, the potency of a nutritional supplement containing nuclear fraction of bovine thymus in enhancing the functional recovery from TBI.

Unveiling putative modulators of mutable collagenous tissue in the brittle star Ophiomastix wendtii: an RNA-Seq analysis.

Collagenous connective tissue, found throughout the bodies of metazoans, plays a crucial role in maintaining structural integrity. This versatile tissue has the potential for numerous biomedical applications, including the development of innovative collagen-based biomaterials. Inspiration for such advancements can be drawn from echinoderms, a group of marine invertebrates that includes sea stars, sea cucumbers, brittle stars, sea urchins, and sea lilies. Through their nervous system, these organisms can reversibly control the pliability of their connective tissue components (i.e., tendons and ligaments) that are composed of mutable collagenous tissue (MCT). The variable tensile properties of the MCT allow echinoderms to perform unique functions, including postural maintenance, reduction of muscular energy use, autotomy to avoid predators, and asexual reproduction through fission. The changes in the tensile strength of MCT structures are specifically controlled by specialized neurosecretory cells called juxtaligamental cells. These cells release substances that either soften or stiffen the MCT. So far, only a few of these substances have been purified and characterized, and the genetic underpinning of MCT biology remains unknown. Therefore, we have conducted this research to identify MCT-related genes in echinoderms as a first step towards a better understanding of the MCT molecular control mechanisms. Our ultimate goal is to unlock new biomaterial applications based on this knowledge. In this project, we used RNA-Seq to identify and annotate differentially expressed genes in the MCT structures of the brittle star Ophiomastix wendtii. As a result, we present a list of 16 putative MCT modulator genes, which will be validated and characterized in forthcoming functional analyses.

A subterminal growth zone at arm tip likely underlies life-long indeterminate growth in brittle stars.

BACKGROUND: Echinoderms are a phylum of marine invertebrates with close phylogenetic relationships to chordates. Many members of the phylum Echinodermata are capable of extensive post-traumatic regeneration and life-long indeterminate growth. Different from regeneration, the life-long elongation of the main body axis in adult echinoderms has received little attention. The anatomical location and the nature of the dividing progenitor cells contributing to adults' growth is unknown. RESULTS: We show that the proliferating cells that drive the life-long growth of adult brittle star arms are mostly localized to the subterminal (second from the tip) arm segment. Each of the major anatomical structures contains dividing progenitors. These structures include: the radial nerve, water-vascular canal, and arm coelomic wall. Some of those proliferating progenitor cells are capable of multiple rounds of cell division. Within the nervous system, the progenitor cells were identified as a subset of radial glial cells that do not express Brn1/2/4, a transcription factor with a conserved role in the neuronal fate specification. In addition to characterizing the growth zone and the nature of the precursor cells, we provide a description of the microanatomy of the four distal-most arm segments contrasting the distal with the proximal segments, which are more mature. CONCLUSIONS: The growth of the adult brittle star arms occurs via proliferation of progenitor cells in the distal segments, which are most abundant in the second segment from the tip. At least some of the progenitors are capable of multiple rounds of cell division. Within the nervous system the dividing cells were identified as Brn1/2/4-negative radial glial cells.

LinkageMapView-rendering high-resolution linkage and QTL maps.

MOTIVATION: Linkage and quantitative trait loci (QTL) maps are critical tools for the study of the genetic basis of complex traits. With the advances in sequencing technology over the past decade, linkage map densities have been increasing dramatically, while the visualization tools have not kept pace. LinkageMapView is a free add-on package written in R that produces high resolution, publication-ready visualizations of linkage and QTL maps. While there is software available to generate linkage map graphics, none are freely available, produce publication quality figures, are open source and can run on all platforms. LinkageMapView can be integrated into map building pipelines as it seamlessly incorporates output from R/qtl and also accepts simple text or comma delimited files. There are numerous options within the package to build highly customizable maps, allow for linkage group comparisons, and annotate QTL regions. AVAILABILITY AND IMPLEMENTATION: https://cran.r-project.org/web/packages/LinkageMapView/.

EchinoDB, an application for comparative transcriptomics of deeply-sampled clades of echinoderms.

BACKGROUND: One of our goals for the echinoderm tree of life project (http://echinotol.org) is to identify orthologs suitable for phylogenetic analysis from next-generation transcriptome data. The current dataset is the largest assembled for echinoderm phylogeny and transcriptomics. We used RNA-Seq to profile adult tissues from 42 echinoderm specimens from 24 orders and 37 families. In order to achieve sampling members of clades that span key evolutionary divergence, many of our exemplars were collected from deep and polar seas. DESCRIPTION: A small fraction of the transcriptome data we produced is being used for phylogenetic reconstruction. Thus to make a larger dataset available to researchers with a wide variety of interests, we made a web-based application, EchinoDB (http://echinodb.uncc.edu). EchinoDB is a repository of orthologous transcripts from echinoderms that is searchable via keywords and sequence similarity. CONCLUSIONS: From transcripts we identified 749,397 clusters of orthologous loci. We have developed the information technology to manage and search the loci their annotations with respect to the Sea Urchin (Strongylocentrotus purpuratus) genome. Several users have already taken advantage of these data for spin-off projects in developmental biology, gene family studies, and neuroscience. We hope others will search EchinoDB to discover datasets relevant to a variety of additional questions in comparative biology.

Genetic analysis of glucosinolate variability in broccoli florets using genome-anchored single nucleotide polymorphisms.

KEY MESSAGE: The identification of genetic factors influencing the accumulation of individual glucosinolates in broccoli florets provides novel insight into the regulation of glucosinolate levels in Brassica vegetables and will accelerate the development of vegetables with glucosinolate profiles tailored to promote human health. Quantitative trait loci analysis of glucosinolate (GSL) variability was conducted with a B. oleracea (broccoli) mapping population, saturated with single nucleotide polymorphism markers from a high-density array designed for rapeseed (Brassica napus). In 4 years of analysis, 14 QTLs were associated with the accumulation of aliphatic, indolic, or aromatic GSLs in floret tissue. The accumulation of 3-carbon aliphatic GSLs (2-propenyl and 3-methylsulfinylpropyl) was primarily associated with a single QTL on C05, but common regulation of 4-carbon aliphatic GSLs was not observed. A single locus on C09, associated with up to 40 % of the phenotypic variability of 2-hydroxy-3-butenyl GSL over multiple years, was not associated with the variability of precursor compounds. Similarly, QTLs on C02, C04, and C09 were associated with 4-methylsulfinylbutyl GSL concentration over multiple years but were not significantly associated with downstream compounds. Genome-specific SNP markers were used to identify candidate genes that co-localized to marker intervals and previously sequenced Brassica oleracea BAC clones containing known GSL genes (GSL-ALK, GSL-PRO, and GSL-ELONG) were aligned to the genomic sequence, providing support that at least three of our 14 QTLs likely correspond to previously identified GSL loci. The results demonstrate that previously identified loci do not fully explain GSL variation in broccoli. The identification of additional genetic factors influencing the accumulation of GSL in broccoli florets provides novel insight into the regulation of GSL levels in Brassicaceae and will accelerate development of vegetables with modified or enhanced GSL profiles.

High-density single nucleotide polymorphism (SNP) array mapping in Brassica oleracea: identification of QTL associated with carotenoid variation in broccoli florets.

KEY MESSAGE: A high-resolution genetic linkage map of B. oleracea was developed from a B. napus SNP array. The work will facilitate genetic and evolutionary studies in Brassicaceae. A broccoli population, VI-158 × BNC, consisting of 150 F2:3 families was used to create a saturated Brassica oleracea (diploid: CC) linkage map using a recently developed rapeseed (Brassica napus) (tetraploid: AACC) Illumina Infinium single nucleotide polymorphism (SNP) array. The map consisted of 547 non-redundant SNP markers spanning 948.1 cM across nine chromosomes with an average interval size of 1.7 cM. As the SNPs are anchored to the genomic reference sequence of the rapid cycling B. oleracea TO1000, we were able to estimate that the map provides 96 % coverage of the diploid genome. Carotenoid analysis of 2 years data identified 3 QTLs on two chromosomes that are associated with up to half of the phenotypic variation associated with the accumulation of total or individual compounds. By searching the genome sequences of the two related diploid species (B. oleracea and B. rapa), we further identified putative carotenoid candidate genes in the region of these QTLs. This is the first description of the use of a B. napus SNP array to rapidly construct high-density genetic linkage maps of one of the constituent diploid species. The unambiguous nature of these markers with regard to genomic sequences provides evidence to the nature of genes underlying the QTL, and demonstrates the value and impact this resource will have on Brassica research.

Genetic basis and selection of glyceollin elicitation in wild soybean.

Glyceollins, a family of phytoalexins elicited in legume species, play crucial roles in environmental stress response (e.g., defending against pathogens) and human health. However, little is known about the genetic basis of glyceollin elicitation. In the present study, we employed a metabolite-based genome-wide association (mGWA) approach to identify candidate genes involved in glyceollin elicitation in genetically diverse and understudied wild soybeans subjected to soybean cyst nematode. In total, eight SNPs on chromosomes 3, 9, 13, 15, and 20 showed significant associations with glyceollin elicitation. Six genes fell into two gene clusters that encode glycosyltransferases in the phenylpropanoid pathway and were physically close to one of the significant SNPs (ss715603454) on chromosome 9. Additionally, transcription factors (TFs) genes such as MYB and WRKY were also found as promising candidate genes within close linkage to significant SNPs on chromosome 9. Notably, four significant SNPs on chromosome 9 show epistasis and a strong signal for selection. The findings describe the genetic foundation of glyceollin biosynthesis in wild soybeans; the identified genes are predicted to play a significant role in glyceollin elicitation regulation in wild soybeans. Additionally, how the epistatic interactions and selection influence glyceollin variation in natural populations deserves further investigation to elucidate the molecular mechanism of glyceollin biosynthesis.

Flavonols improve thermotolerance in tomato pollen during germination and tube elongation by maintaining ROS homeostasis.

Elevated temperatures impair pollen performance and reproductive success, resulting in lower crop yields. The Solanum lycopersicum anthocyanin reduced ( are ) mutant has a FLAVANONE 3 HYDROXYLASE ( F3H ) gene mutation resulting in impaired synthesis of flavonol antioxidants. The are mutant has reduced pollen performance and seed set relative to the VF36 parental line, which is accentuated at elevated temperatures. Transformation of are with the wild-type F3H gene, or chemical complementation with flavonols, prevented temperature-dependent ROS accumulation in pollen and reversed are's reduced viability, germination, and tube elongation to VF36 levels. VF36 transformed with an F3H overexpression construct prevented temperature driven ROS increases and impaired pollen performance, revealing thermotolerance results from elevated flavonol synthesis. Although stigmas of are had reduced flavonols and elevated ROS, the growth of are pollen tubes were similarly impaired in both are and VF36 pistils. RNA-Seq was performed at optimal and stress temperatures in are , VF36, and the VF36 F3H overexpression line at multiple timepoints across pollen tube elongation. Differentially expressed gene numbers increased with duration of elevated temperature in all genotypes, with the largest number in are . These findings suggest potential agricultural interventions to combat the negative effects of heat-induced ROS in pollen that leads to reproductive failure. One sentence summary: Flavonol antioxidants reduce the negative impacts of elevated temperatures on pollen performance by reducing levels of heat induced reactive oxygen species and modulation of heat-induced changes in the pollen transcriptome.

Enhanced pollen tube performance at high temperature contributes to thermotolerant fruit production in tomato.

Rising temperature extremes during critical reproductive periods threaten the yield of major grain and fruit crops. Flowering plant reproduction depends on development of sufficient numbers of pollen grains and on their ability to generate a cellular extension, the pollen tube, which elongates through the pistil to deliver sperm cells to female gametes for double fertilization. These critical phases of the life cycle are sensitive to temperature and limit productivity under high temperature (HT). Previous studies have investigated the effects of HT on pollen development, but little is known about how HT applied during the pollen tube growth phase affects fertility. Here, we used tomato as a model fruit crop to determine how HT affects the pollen tube growth phase, taking advantage of cultivars noted for fruit production in exceptionally hot growing seasons. We found that exposure to HT solely during the pollen tube growth phase limits fruit biomass and seed set more significantly in thermosensitive cultivars than in thermotolerant cultivars. Importantly, we found that pollen tubes from the thermotolerant Tamaulipas cultivar have enhanced growth in vivo and in vitro under HT. Analysis of the pollen tube transcriptome's response to HT allowed us to develop hypotheses for the molecular basis of cellular thermotolerance in the pollen tube and we define two response modes (enhanced induction of stress responses, and higher basal levels of growth pathways repressed by heat stress) associated with reproductive thermotolerance. Importantly, we define key components of the pollen tube stress response identifying enhanced ROS homeostasis and pollen tube callose synthesis and deposition as important components of reproductive thermotolerance in Tamaulipas. Our work identifies the pollen tube growth phase as a viable target to enhance reproductive thermotolerance and delineates key pathways that are altered in crop varieties capable of fruiting under HT conditions.

Association between composition of the human gastrointestinal microbiome and development of fatty liver with choline deficiency.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease affects up to 30% of the US population, but the mechanisms underlying this condition are incompletely understood. We investigated how diet standardization and choline deficiency influence the composition of the microbial community in the human gastrointestinal tract and the development of fatty liver under conditions of choline deficiency. METHODS: We performed a 2-month inpatient study of 15 female subjects who were placed on well-controlled diets in which choline levels were manipulated. We used 454-FLX pyrosequencing of 16S ribosomal RNA bacterial genes to characterize microbiota in stool samples collected over the course of the study. RESULTS: The compositions of the gastrointestinal microbial communities changed with choline levels of diets; each individual's microbiome remained distinct for the duration of the experiment, even though all subjects were fed identical diets. Variations between subjects in levels of Gammaproteobacteria and Erysipelotrichi were directly associated with changes in liver fat in each subject during choline depletion. Levels of these bacteria, change in amount of liver fat, and a single nucleotide polymorphism that affects choline were combined into a model that accurately predicted the degree to which subjects developed fatty liver on a choline-deficient diet. CONCLUSIONS: Host factors and gastrointestinal bacteria each respond to dietary choline deficiency, although the gut microbiota remains distinct in each individual. We identified bacterial biomarkers of fatty liver that result from choline deficiency, adding to the accumulating evidence that gastrointestinal microbes have a role in metabolic disorders.

EchinoDB: an update to the web-based application for genomic and transcriptomic data on echinoderms.

BACKGROUND: Here we release a new version of EchinoDB, EchinoDB v2.0 ( https://echinodb.uncc.edu ). EchinoDB is a database of genomic and transcriptomic data on echinoderms. The initial database consisted of groups of 749,397 orthologous and paralogous transcripts arranged in orthoclusters by sequence similarity. RESULTS: The updated version of EchinoDB includes two new major datasets: the RNA-Seq data of the brittle star Ophioderma brevispinum and the high-quality genomic assembly data of the green sea urchin Lytechinus variegatus. In addition, we enabled keyword searches for annotated data and installed an updated version of Sequenceserver to allow Basic Local Alignment Search Tool (BLAST) searches. The data are downloadable in FASTA format. The first version of EchinoDB appeared in 2016 and was implemented in GO on a local server. The new version has been updated using R Shiny to include new features and improvements in the application. Furthermore, EchinoDB now runs entirely in the cloud for increased reliability and scaling. CONCLUSION: EchinoDB serves a user base drawn from the fields of phylogenetics, developmental biology, genomics, physiology, neurobiology, and regeneration. As use cases, we illustrate the function of EchinoDB in retrieving components of signaling pathways involved in the tissue regeneration process of different echinoderms, including the emerging model species Ophioderma brevispinum. Moreover, we use EchinoDB to shed light on the conservation of the molecular components involved in two echinoderm-specific phenomena: spicule matrix proteins involved in the formation of stereom endoskeleton and the tensilin protein that contributes to the capacity of the connective tissues to quickly change its mechanical properties. The genes involved in the former had been previously studied in echinoids, while gene sequences involved in the latter had been previously described in holothuroids. Specifically, we ask (a) if the biomineralization-related proteins previously reported only in sea urchins are also present in other, non-echinoid, echinoderms and (b) if tensilin, the protein responsible for the control of stiffness of the mutable collagenous tissue, previously described in sea cucumbers, is conserved across the phylum.

Automated gene data integration with Databio.

OBJECTIVE: Although sequencing and other high-throughput data production technologies are increasingly affordable, data analysis and interpretation remains a significant factor in the cost of -omics studies. Despite the broad acceptance of findable, accessible, interoperable, and reusable (FAIR) data principles which focus on data discoverability and annotation, data integration remains a significant bottleneck in linking prior work in order to better understand novel research. Relevant and timely information discovery is difficult for increasingly multi-disciplinary projects when scientists cannot easily keep up with work across multiple fields. Computational tools are necessary to accurately describe data contents, and empower linkage to existing resources without prior knowledge of the various database resources. RESULTS: We developed the Databio tool, accessible at https://datab.io/, to automate data parsing, identifier detection, and streamline common tasks to provide a point-and-click approach to data manipulation and integration in life sciences research and translational medicine. Databio uses fast real-time data structures and a data warehouse of 137 million identifiers, with automated heuristics to describe data provenance without highly specialized knowledge or bioinformatics training.

Indomethacin enhances anti-tumor efficacy of a MUC1 peptide vaccine against breast cancer in MUC1 transgenic mice.

In recent years, vaccines against tumor antigens have shown potential for combating invasive cancers, including primary tumors and metastatic lesions. This is particularly pertinent for breast cancer, which is the second-leading cause of cancer-related death in women. MUC1 is a glycoprotein that is normally expressed on glandular epithelium, but is overexpressed and under-glycosylated in most human cancers, including the majority of breast cancers. This under-glycosylation exposes the MUC1 protein core on the tumor-associated form of the protein. We have previously shown that a vaccine consisting of MUC1 core peptides stimulates a tumor-specific immune response. However, this immune response is dampened by the immunosuppressive microenvironment within breast tumors. Thus, in the present study, we investigated the effectiveness of MUC1 vaccination in combination with four different drugs that inhibit different components of the COX pathway: indomethacin (COX-1 and COX-2 inhibitor), celecoxib (COX-2 inhibitor), 1-methyl tryptophan (indoleamine 2,3 dioxygenase inhibitor), and AH6809 (prostaglandin E2 receptor antagonist). These treatment regimens were explored for the treatment of orthotopic MUC1-expressing breast tumors in mice transgenic for human MUC1. We found that the combination of vaccine and indomethacin resulted in a significant reduction in tumor burden. Indomethacin did not increase tumor-specific immune responses over vaccine alone, but rather appeared to reduce the proliferation and increase apoptosis of tumor cells, thus rendering them susceptible to immune cell killing.

Determining gene expression on a single pair of microarrays.

BACKGROUND: In microarray experiments the numbers of replicates are often limited due to factors such as cost, availability of sample or poor hybridization. There are currently few choices for the analysis of a pair of microarrays where N = 1 in each condition. In this paper, we demonstrate the effectiveness of a new algorithm called PINC (PINC is Not Cyber-T) that can analyze Affymetrix microarray experiments. RESULTS: PINC treats each pair of probes within a probeset as an independent measure of gene expression using the Bayesian framework of the Cyber-T algorithm and then assigns a corrected p-value for each gene comparison.The p-values generated by PINC accurately control False Discovery rate on Affymetrix control data sets, but are small enough that family-wise error rates (such as the Holm's step down method) can be used as a conservative alternative to false discovery rate with little loss of sensitivity on control data sets. CONCLUSION: PINC outperforms previously published methods for determining differentially expressed genes when comparing Affymetrix microarrays with N = 1 in each condition. When applied to biological samples, PINC can be used to assess the degree of variability observed among biological replicates in addition to analyzing isolated pairs of microarrays.

Connecting nutrition composition measures to biomedical research.

OBJECTIVES: Biomedical research is gaining ground on human disease through many types of "omics", which is leading to increasingly effective treatments and broad applications for precision medicine. The majority of disease treatments still revolve around drugs and biologics. Although food is consumed in much higher quantities, we understand very little about how the human body metabolizes and uses the full range of nutrients, or how these processes affect human health and disease risk. Nutrient composition databases are used by dietitians to describe common consumer food products, but these fail to identify chemicals with the same nomenclature as metabolic pathways in basic life sciences research and with far less precision. Consumer-oriented nutrient compositions often describe generic substances (e.g. Sugars) while scientific reporting is often much more specific (e.g. Dextrose, Fructose, etc.). Integrating these two fields of research presents a difficult challenge for novel applications of precision nutrition. DATA DESCRIPTION: This data set provides a manually curated collection of nutrient identifiers from the USDA's Nutrition Data Bases and maps them to PubChem (a resource for cheminformatics and drug discovery research), biomedical literature records in PubMed using Medical Subject Headings, biological pathways using the Chemical Entities of Biological Interest ontology.

A Consensus Map in Cultivated Hexaploid Oat Reveals Conserved Grass Synteny with Substantial Subgenome Rearrangement.

Hexaploid oat ( L., 2 = 6 = 42) is a member of the Poaceae family and has a large genome (∼12.5 Gb) containing 21 chromosome pairs from three ancestral genomes. Physical rearrangements among parental genomes have hindered the development of linkage maps in this species. The objective of this work was to develop a single high-density consensus linkage map that is representative of the majority of commonly grown oat varieties. Data from a cDNA-derived single-nucleotide polymorphism (SNP) array and genotyping-by-sequencing (GBS) were collected from the progeny of 12 biparental recombinant inbred line populations derived from 19 parents representing oat germplasm cultivated primarily in North America. Linkage groups from all mapping populations were compared to identify 21 clusters of conserved collinearity. Linkage groups within each cluster were then merged into 21 consensus chromosomes, generating a framework consensus map of 7202 markers spanning 2843 cM. An additional 9678 markers were placed on this map with a lower degree of certainty. Assignment to physical chromosomes with high confidence was made for nine chromosomes. Comparison of homeologous regions among oat chromosomes and matches to orthologous regions of rice ( L.) reveal that the hexaploid oat genome has been highly rearranged relative to its ancestral diploid genomes as a result of frequent translocations among chromosomes. Heterogeneous chromosome rearrangements among populations were also evident, probably accounting for the failure of some linkage groups to match the consensus. This work contributes to a further understanding of the organization and evolution of hexaploid grass genomes.

Phylotranscriptomic analysis uncovers a wealth of tissue inhibitor of metalloproteinases variants in echinoderms.

Tissue inhibitors of metalloproteinases (TIMPs) help regulate the extracellular matrix (ECM) in animals, mostly by inhibiting matrix metalloproteinases (MMPs). They are important activators of mutable collagenous tissue (MCT), which have been extensively studied in echinoderms, and the four TIMP copies in humans have been studied for their role in cancer. To understand the evolution of TIMPs, we combined 405 TIMPs from an echinoderm transcriptome dataset built from 41 specimens representing all five classes of echinoderms with variants from protostomes and chordates. We used multiple sequence alignment with various stringencies of alignment quality to cull highly divergent sequences and then conducted phylogenetic analyses using both nucleotide and amino acid sequences. Phylogenetic hypotheses consistently recovered TIMPs as diversifying in the ancestral deuterostome and these early lineages continuing to diversify in echinoderms. The four vertebrate TIMPs diversified from a single copy in the ancestral chordate, all other copies being lost. Consistent with greater MCT needs owing to body wall liquefaction, evisceration, autotomy and reproduction by fission, holothuroids had significantly more TIMPs and higher read depths per contig. Ten cysteine residues, an HPQ binding site and several other residues were conserved in at least 70% of all TIMPs. The conservation of binding sites and the placement of echinoderm TIMPs involved in MCT modification suggest that ECM regulation remains the primary function of TIMP genes, although within this role there are a large number of specialized copies.

Medtronic Freestyle valve for right ventricular reconstruction in pediatric Ross operations.

BACKGROUND: The use of homograft conduits to reconstruct right ventricle (RV) to pulmonary artery (PA) connections is an essential component of the Ross operation. Homograft availability and cost may be problematic when considering the Ross operation. We elected in January 1998 to utilize commercially available xenografts as an alternative to homografts for RV/PA reconstruction in the pediatric Ross operation. Our early results using the Medtronic Freestyle valve (Medtronic, Minneapolis, MN) for RV/PA reconstruction are presented. METHODS: We reviewed our database for all Ross operations performed on children since January 1998. A total of 16 patients were identified. Eleven children received a Medtronic Freestyle valve, 2 children received a homograft, and 3 children received another type of xenograft. Echocardiographic evaluation of all children who received the Medtronic Freestyle valve was performed at hospital discharge and at two subsequent outpatient evaluations. RESULTS: The median peak instantaneous pressure gradient across the xenograft was 16 +/- 9 mm Hg (immediately after surgery before hospital discharge); 22 +/- 20 mm Hg at 23 +/- 11 months (first postdischarge follow-up); and 27 +/- 20 mm Hg at 35 +/- 9 months (second postdischarge follow-up). Linear regression analysis revealed an increasing pressure gradient with time (R(2)-adjusted = 0.44, p < 0.0001). At the same three observation points, the xenograft annulus diameter decreased: 25 +/- 1.2 mm; 19 +/- 4.3 mm; and 20 +/- 1.8 mm. Linear regression analysis revealed a decreasing annulus diameter with time (R(2)-adjusted = 0.41, p < 0.0001). CONCLUSIONS: The Medtronic Freestyle valve provides a possible alternative to homografts for the reconstruction of the RV/PA connection in the pediatric Ross operation. Long-term follow-up is necessary to evaluate this xenograft as an alternative to the homograft.