Was There a Cambrian Explosion on Land? The Case of Arthropod Terrestrialization.

Arthropods, the most diverse form of macroscopic life in the history of the Earth, originated in the sea. Since the early Cambrian, at least ~518 million years ago, these animals have dominated the oceans of the world. By the Silurian-Devonian, the fossil record attests to arthropods becoming the first animals to colonize land, However, a growing body of molecular dating and palaeontological evidence suggests that the three major terrestrial arthropod groups (myriapods, hexapods, and arachnids), as well as vascular plants, may have invaded land as early as the Cambrian-Ordovician. These dates precede the oldest fossil evidence of those groups and suggest an unrecorded continental "Cambrian explosion" a hundred million years prior to the formation of early complex terrestrial ecosystems in the Silurian-Devonian. We review the palaeontological, phylogenomic, and molecular clock evidence pertaining to the proposed Cambrian terrestrialization of the arthropods. We argue that despite the challenges posed by incomplete preservation and the scarcity of early Palaeozoic terrestrial deposits, the discrepancy between molecular clock estimates and the fossil record is narrower than is often claimed. We discuss strategies for closing the gap between molecular clock estimates and fossil data in the evolution of early ecosystems on land.

A vegetative storage protein improves drought tolerance in maize.

Vegetative storage proteins (VSPs) are known to serve as nitrogen reserves in many dicot plants but remain undiscovered in grasses, most widely grown group of crops globally. We identified and characterized a VSP in maize and demonstrated that its overexpression improved drought tolerance. Nitrogen supplementation selectively induced a mesophyll lipoxygenase (ZmLOX6), which was targeted to chloroplasts by a novel N-terminal transit peptide of 62 amino acids. When ectopically expressed under the control of various tissue-specific promoters, it accumulated to a fivefold higher level upon expression in the mesophyll cells than the wild-type plants. Constitutive expression or targeted expression specifically to the bundle sheath cells increased its accumulation by less than twofold. The overexpressed ZmLOX6 was remobilized from the leaves like other major proteins during grain development. Evaluated in the field over locations and years, transgenic hybrids overexpressing ZmLOX6 in the mesophyll cells significantly outyielded nontransgenic sibs under managed drought stress imposed at flowering. Additional storage of nitrogen as a VSP in maize leaves ameliorated the effect of drought on grain yield.

Ancestral morphology of Ecdysozoa constrained by an early Cambrian stem group ecdysozoan.

BACKGROUND: Ecdysozoa are the moulting protostomes, including arthropods, tardigrades, and nematodes. Both the molecular and fossil records indicate that Ecdysozoa is an ancient group originating in the terminal Proterozoic, and exceptional fossil biotas show their dominance and diversity at the beginning of the Phanerozoic. However, the nature of the ecdysozoan common ancestor has been difficult to ascertain due to the extreme morphological diversity of extant Ecdysozoa, and the lack of early diverging taxa in ancient fossil biotas. RESULTS: Here we re-describe Acosmia maotiania from the early Cambrian Chengjiang Biota of Yunnan Province, China and assign it to stem group Ecdysozoa. Acosmia features a two-part body, with an anterior proboscis bearing a terminal mouth and muscular pharynx, and a posterior annulated trunk with a through gut. Morphological phylogenetic analyses of the protostomes using parsimony, maximum likelihood and Bayesian inference, with coding informed by published experimental decay studies, each placed Acosmia as sister taxon to Cycloneuralia + Panarthropoda-i.e. stem group Ecdysozoa. Ancestral state probabilities were calculated for key ecdysozoan nodes, in order to test characters inferred from fossils to be ancestral for Ecdysozoa. Results support an ancestor of crown group ecdysozoans sharing an annulated vermiform body with a terminal mouth like Acosmia, but also possessing the pharyngeal armature and circumoral structures characteristic of Cambrian cycloneuralians and lobopodians. CONCLUSIONS: Acosmia is the first taxon placed in the ecdysozoan stem group and provides a constraint to test hypotheses on the early evolution of Ecdysozoa. Our study suggests acquisition of pharyngeal armature, and therefore a change in feeding strategy (e.g. predation), may have characterised the origin and radiation of crown group ecdysozoans from Acosmia-like ancestors.

Arachnid monophyly: Morphological, palaeontological and molecular support for a single terrestrialization within Chelicerata.

The majority of extant arachnids are terrestrial, but other chelicerates are generally aquatic, including horseshoe crabs, sea spiders, and the extinct eurypterids. It is necessary to determine whether arachnids are exclusively descended from a single common ancestor (monophyly), because only that relationship is compatible with one land colonisation in chelicerate evolutionary history. Some studies have cast doubt on arachnid monophyly and recast the origins of their terrestrialization. These include some phylogenomic analyses placing horseshoe crabs within Arachnida, and from aquatic Palaeozoic stem-group scorpions. Here, we evaluate the possibility of arachnid monophyly by considering morphology, fossils and molecules holistically. We argue arachnid monophyly obviates the need to posit reacquisition/retention of aquatic characters such as gnathobasic feeding and book gills without trabeculae from terrestrial ancestors in horseshoe crabs, and that the scorpion total-group contains few aquatic taxa. We built a matrix composed of 200 slowly-evolving genes and re-analysed two published molecular datasets. We retrieved arachnid monophyly where other studies did not - highlighting the difficulty of resolving chelicerate relationships from current molecular data. As such, we consider arachnid monophyly the best-supported hypothesis. Finally, we inferred that arachnids terrestrialized during the Cambrian-Ordovician using the slow-evolving molecular matrix, in agreement with recent analyses.

We listed patients and we should transplant them.

Twenty percent of kidneys recovered for transplantation are discarded. The most common reason for not transplanting these kidneys is to organ quality and biopsy findings. Yet, organ quality measures are not associated with discard rates and kidneys with poorer quality measures lead to greater life span for the recipient compared to staying on dialysis. Biopsy findings are not correlated with graft survival in most cases. The risk aversion of transplant centers from using "high-risk" kidneys can be, in part at least, attributed to negative consequences of poor graft survival with possible program sanctions or possible loss of insurance contracts. CMS has taken a first step by eliminating short-term graft survival as a performance measure for transplant centers. Many of the discarded kidneys will provide good results if transplanted and would recognize that patients value getting a transplant above graft survival.

A Tube-Dwelling Early Cambrian Lobopodian.

Facivermis yunnanicus [1, 2] is an enigmatic worm-like animal from the early Cambrian Chengjiang Biota of Yunnan Province, China. It is a small (<10 cm) bilaterian with five pairs of spiny anterior arms, an elongated body, and a swollen posterior end. The unusual morphology of Facivermis has prompted a history of diverse taxonomic interpretations, including among annelids [1, 3], lophophorates [4], and pentastomids [5]. However, in other studies, Facivermis is considered to be more similar to lobopodians [2, 6-8]-the fossil grade from which modern panarthropods (arthropods, onychophorans, and tardigrades) are derived. In these studies, Facivermis is thought to be intermediate between cycloneuralian worms and lobopodians. Facivermis has therefore been suggested to represent an early endobenthic-epibenthic panarthropod transition [6] and to provide crucial insights into the origin of paired appendages [2]. However, the systematic affinity of Facivermis was poorly supported in a previous phylogeny [6], partially due to incomplete understanding of its morphology. Therefore, the evolutionary significance of Facivermis remains unresolved. In this study, we re-examine Facivermis from new material and the holotype, leading to the discovery of several new morphological features, such as paired eyes on the head and a dwelling tube. Comprehensive phylogenetic analyses using parsimony, Bayesian inference, and maximum likelihood all support Facivermis as a luolishaniid in a derived position within the onychophoran stem group rather than as a basal panarthropod. In contrast to previous studies, we therefore conclude that Facivermis provides a rare early Cambrian example of secondary loss to accommodate a highly specialized tube-dwelling lifestyle.

Discovery of midgut genes for the RNA interference control of corn rootworm.

RNA interference (RNAi) is a promising new technology for corn rootworm control. This paper presents the discovery of new gene targets - dvssj1 and dvssj2, in western corn rootworm (WCR). Dvssj1 and dvssj2 are orthologs of the Drosophila genes snakeskin (ssk) and mesh, respectively. These genes encode membrane proteins associated with smooth septate junctions (SSJ) which are required for intestinal barrier function. Based on bioinformatics analysis, dvssj1 appears to be an arthropod-specific gene. Diet based insect feeding assays using double-stranded RNA (dsRNA) targeting dvssj1 and dvssj2 demonstrate targeted mRNA suppression, larval growth inhibition, and mortality. In RNAi treated WCR, injury to the midgut was manifested by "blebbing" of the midgut epithelium into the gut lumen. Ultrastructural examination of midgut epithelial cells revealed apoptosis and regenerative activities. Transgenic plants expressing dsRNA targeting dvssj1 show insecticidal activity and significant plant protection from WCR damage. The data indicate that dvssj1 and dvssj2 are effective gene targets for the control of WCR using RNAi technology, by apparent suppression of production of their respective smooth septate junction membrane proteins located within the intestinal lining, leading to growth inhibition and mortality.

Views of US Voters on Compensating Living Kidney Donors.

IMPORTANCE: Patients in the United States waiting for kidney transplantation die in increasing numbers owing to the severe kidney shortage, which might be alleviated by compensating living kidney donors. OBJECTIVE: To determine the willingness of voting US citizens to become living kidney donors and to ascertain the potential influence of compensation for donation. DESIGN, SETTING, AND PARTICIPANTS: A professionally designed quantitative survey was administered by an international polling firm in June 2014. Information was collected on willingness to donate a kidney and the potential influence of compensation ($50 000); survey data included respondent age, income, education level, sex, US region, race/ethnicity, marital status, political affiliation, likelihood to vote, and employment status. The survey was performed via a random-digit dialing process that selected respondents via both landlines and mobile telephones to improve population representation. The survey included 1011 registered US voters likely to vote. MAIN OUTCOMES AND MEASURES: The degree to which the US voting public is willing to donate a kidney and the perceptions of current voters toward paying living kidney donors. RESULTS: Of the 1011 respondents, 427 were male and 584 were female, with 43% of participants between ages 45 and 64 years. With respondents grouped by willingness to donate, we found that 689 (68%) would donate a kidney to anyone and 235 (23%) only to certain persons; 87 (9%) would not donate. Most (59%) indicated that payment of $50 000 would make them even more likely to donate a kidney, 32% were unmoved by compensation, and 9% were negatively influenced by payment. CONCLUSIONS AND RELEVANCE: Most US voters view living kidney donation positively, and most would be motivated toward donor nephrectomy if offered a payment of $50 000. Because most registered voters favor such payments, and because thousands of lives might be saved should compensation increase the number of transplantable kidneys, laws and regulations prohibiting donor compensation should be modified to allow pilot studies of financial incentives for living kidney donors. Outcomes of such trials could then result in evidence-based policies, which would incorporate fair and just compensation to those persons willing to undergo donor nephrectomy.

Broad 4-hydroxyphenylpyruvate dioxygenase inhibitor herbicide tolerance in soybean with an optimized enzyme and expression cassette.

With an optimized expression cassette consisting of the soybean (Glycine max) native promoter modified for enhanced expression driving a chimeric gene coding for the soybean native amino-terminal 86 amino acids fused to an insensitive shuffled variant of maize (Zea mays) 4-hydroxyphenylpyruvate dioxygenase (HPPD), we achieved field tolerance in transgenic soybean plants to the HPPD-inhibiting herbicides mesotrione, isoxaflutole, and tembotrione. Directed evolution of maize HPPD was accomplished by progressively incorporating amino acids from naturally occurring diversity and novel substitutions identified by saturation mutagenesis, combined at random through shuffling. Localization of heterologously expressed HPPD mimicked that of the native enzyme, which was shown to be dually targeted to chloroplasts and the cytosol. Analysis of the native soybean HPPD gene revealed two transcription start sites, leading to transcripts encoding two HPPD polypeptides. The N-terminal region of the longer encoded peptide directs proteins to the chloroplast, while the short form remains in the cytosol. In contrast, maize HPPD was found almost exclusively in chloroplasts. Evolved HPPD enzymes showed insensitivity to five inhibitor herbicides. In 2013 field trials, transgenic soybean events made with optimized promoter and HPPD variant expression cassettes were tested with three herbicides and showed tolerance to four times the labeled rates of mesotrione and isoxaflutole and two times the labeled rates of tembotrione.

Maize ARGOS1 (ZAR1) transgenic alleles increase hybrid maize yield.

Crop improvement for yield and drought tolerance is challenging due to the complex genetic nature of these traits and environmental dependencies. This study reports that transgenic over-expression of Zea mays AR GOS1 (ZAR1) enhanced maize organ growth, grain yield, and drought-stress tolerance. The ZAR1 transgene exhibited environmental interactions, with yield increase under Temperate Dry and yield reduction under Temperate Humid or High Latitude environments. Native ZAR1 allele variation associated with drought-stress tolerance. Two founder alleles identified in the mid-maturity germplasm of North America now predominate in Pioneer's modern breeding programme, and have distinct proteins, promoters and expression patterns. These two major alleles show heterotic group partitioning, with one predominant in Pioneer's female and the other in the male heterotic groups, respectively. These two alleles also associate with favourable crop performance when heterozygous. Allele-specific transgene testing showed that, of the two alleles discussed here, each allele differed in their impact on yield and environmental interactions. Moreover, when transgenically stacked together the allelic pair showed yield and environmental performance advantages over either single allele, resembling heterosis effects. This work demonstrates differences in transgenic efficacy of native alleles and the differences reflect their association with hybrid breeding performance.

Could it be Quetiapine-induced Peripartum Cardiomyopathy?

Peri-partum Cardiomyopathy (PPCM) is a rare and life threatening complication of pregnancy. There are only two cases registered with the World Health Organization of cases of cardiomyopathy in patients taking Quetiapine. Here we discuss an interesting case of potential Quetiapine induced cardiomyopathy.

Lifestyle transitions in plant pathogenic Colletotrichum fungi deciphered by genome and transcriptome analyses.

Colletotrichum species are fungal pathogens that devastate crop plants worldwide. Host infection involves the differentiation of specialized cell types that are associated with penetration, growth inside living host cells (biotrophy) and tissue destruction (necrotrophy). We report here genome and transcriptome analyses of Colletotrichum higginsianum infecting Arabidopsis thaliana and Colletotrichum graminicola infecting maize. Comparative genomics showed that both fungi have large sets of pathogenicity-related genes, but families of genes encoding secreted effectors, pectin-degrading enzymes, secondary metabolism enzymes, transporters and peptidases are expanded in C. higginsianum. Genome-wide expression profiling revealed that these genes are transcribed in successive waves that are linked to pathogenic transitions: effectors and secondary metabolism enzymes are induced before penetration and during biotrophy, whereas most hydrolases and transporters are upregulated later, at the switch to necrotrophy. Our findings show that preinvasion perception of plant-derived signals substantially reprograms fungal gene expression and indicate previously unknown functions for particular fungal cell types.

History of deceased organ donation, transplantation, and organ procurement organizations.

The historical development of deceased organ donation, transplantation, and organ procurement organizations is reviewed. The concept of transplantation, taking parts from one animal or person and putting them into another animal or person, is ancient. The development of organ transplantation brought on the need for a source of organs. Although many early kidney transplants used kidneys from living donors, these donors could not satisfy the ever-growing need for organs, and extrarenal organs were recovered only from deceased donors. This need for organs to satisfy the great demand led to specialized organizations to identify deceased donors, manage them until recovery occurred, and to notify transplant centers that organs were available for their patients. The functions of these organ procurement organizations expanded to include other required functions such as education, accounting, and compliance with state and federal requirements. Because of the shortage of organs relative to the demand, lack of a unified organ allocation system, the perception that organs are a national resource and should be governed by national regulations, and to improve results of organ procurement organizations and transplant centers, the federal government has regulated virtually all phases of organ procurement and transplantation.

The University of Florida Department of Surgery: building a stronger tomorrow on yesterday's foundation.

Established in 1957, the University of Florida Department of Surgery has a solid foundation on which current faculty are driven to build a stronger tomorrow. The department is focused on promoting patient-centered care, expanding its research portfolio to improve techniques and outcomes, and training the surgical leaders of tomorrow. It fosters an environment where faculty, residents, students, and staff challenge long-held traditions with the goal of improving the health of our patients, the quality of our care, and the vitality of our work environment.

Cell Number Regulator1 affects plant and organ size in maize: implications for crop yield enhancement and heterosis.

Genes involved in cell number regulation may affect plant growth and organ size and, ultimately, crop yield. The tomato (genus Solanum) fruit weight gene fw2.2, for instance, governs a quantitative trait locus that accounts for 30% of fruit size variation, with increased fruit size chiefly due to increased carpel ovary cell number. To expand investigation of how related genes may impact other crop plant or organ sizes, we identified the maize (Zea mays) gene family of putative fw2.2 orthologs, naming them Cell Number Regulator (CNR) genes. This family represents an ancient eukaryotic family of Cys-rich proteins containing the PLAC8 or DUF614 conserved motif. We focused on native expression and transgene analysis of the two maize members closest to Le-fw2.2, namely, CNR1 and CNR2. We show that CNR1 reduced overall plant size when ectopically overexpressed and that plant and organ size increased when its expression was cosuppressed or silenced. Leaf epidermal cell counts showed that the increased or decreased transgenic plant and organ size was due to changes in cell number, not cell size. CNR2 expression was found to be negatively correlated with tissue growth activity and hybrid seedling vigor. The effects of CNR1 on plant size and cell number are reminiscent of heterosis, which also increases plant size primarily through increased cell number. Regardless of whether CNRs and other cell number-influencing genes directly contribute to, or merely mimic, heterosis, they may aid generation of more vigorous and productive crop plants.

Family initiated discussions about organ donation at the time of death.

Some family members initiate organ donation discussions before being approached by donor coordinators or healthcare providers. We examined differences between families that did vs. did not initiate organ donation discussions and factors predicting donation consent among those families that self-initiated the discussion. Next-of-kin of donor-eligible individuals (147 donors, 138 non-donors) from one organ procurement organization completed a telephone interview. Seventy-three families (25.6%) first mentioned organ donation, and 54 (74%) of them consented to donation. Several characteristics of the deceased and next-of-kin were associated with whether family members initiated the donation discussion with donation coordinators or healthcare providers. Moreover, family mention of donation was more likely to yield consent when the deceased was younger (OR=0.95, CI=0.92-0.99), next-of-kin was a registered donor (OR=3.86, CI=2.84-6.76), and when family was more satisfied with the healthcare team (OR=1.20, CI=1.04-1.39). Knowing the deceased's donation intentions and being exposed to positive organ donation messages are more likely to trigger families to raise donation with providers. Organ procurement organizations (OPOs) and healthcare providers should work collaboratively to develop strategies for how best to respond to families who initiate this conversation.

Biology of maize kernel infection by Fusarium verticillioides.

Fusarium kernel rot disease starburst symptomatology was characterized fully for the first time. Two maize lines were hand pollinated and inoculated, using a fluorescent protein-expressing transformant of the fungal pathogen Fusarium verticillioides, by introduction of a conidial suspension through the silk channel of intact ears. Microscopy was used to identify the infection court and document initial stages of kernel colonization and subsequent manifestation of macroscopic symptoms. The fungus entered kernels of susceptible line AD38 via an open stylar canal and spread extracellularly and over the kernel through the nucellus region, sporadically entering pericarp and filling the long thick-walled mesocarp cells. Hyphae spread within pericarp from cell to cell via pits, colonizing files of host cells by growing both up and down the kernel in a radial pattern that preceded macroscopic symptom development. The starburst symptom developed subsequently, and mirrored colonization exactly, when there was extensive dissolution of the thick walls of pericarp cells. Line HT1 exhibited a closed stylar canal phenotype and was not susceptible-except when the pericarp surface was breached mechanically. We hypothesize the passive movement of conidia along the surface of silks, perhaps via capillarity, as a possible mechanism for pathogen access to the infection court.

Relationship of exposure to organ donation information to attitudes, beliefs, and donation decisions of next of kin.

CONTEXT: Public education campaigns about organ donation are common, but their association to actual attitudes, beliefs, and decisions about organ donation among family members of donation-eligible individuals is unknown. OBJECTIVE: To examine the sources of organ donation information identified by donor and nondonor families who participated in a large-scale study to examine factors that influence organ donation decisions. DESIGN: Semistructured telephone survey conducted after a passive recruitment strategy. SETTING AND PARTICIPANTS: Participants were 285 next of kin of donor-eligible individuals (147 donors, 138 nondonors) from one organ procurement organization. RESULTS: Most (85.6%) of next of kin were exposed to at least 1 source of donation information that was important to them, although the types of donation information they were exposed to varied widely. White and educated adults were more likely to have been exposed to more donation information than had minorities and persons with less education. Favorable attitudes and beliefs about organ donation, donor designation, and sharing donation intentions with others were all associated with more exposure to different types of donation information. Donation consent was more likely when next of kin had been exposed to more donation information in the months preceding the family member's death. CONCLUSIONS: When examined in the context of other recent research, these findings argue for continued development and implementation of public education campaigns for organ donation, with an emphasis on repeated exposure over time.

CMS oversight, OPOs and transplant centers and the law of unintended consequences.

The Health Resources and Services Administration launched collaboratives with the goals of increasing donation rates, increasing the number of organs transplanted, eliminating deaths on the waiting list and improving outcomes. The Center for Medicare and Medicaid Services (CMS) recently published requirements for organ procurement organizations (OPOs) and transplant centers. Failure to meet CMS performance measures could result in OPOs losing their service area or transplant centers losing their CMS certification. CMS uses analyses by the Scientific Registry of Transplant Recipients (SRTR) to evaluate a transplant center's performance based on risk-adjusted outcomes. However, CMS also uses a more liberal (one-sided) statistical test rendering more centers likely to qualify as low performing. Furthermore, the SRTR model does not incorporate some important patient variables in its statistical model which may result in biased determinations of quality of care. Cumulatively, there is much unexplained variation for transplant outcomes as suggested by the low predictive ability of survival models compared to other disease contexts. OPOs and transplant centers are unlikely to quietly accept their elimination. They may take certain steps that can result in exclusion of candidates who might otherwise benefit from transplantation and/or result in fewer transplants through restricted use of organs thought to carry higher risk of failure. CMS should join with transplant organizations to ensure that the goals of the collaborative are not inhibited by their performance measures.