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Energy conservation in microorganisms is classically categorized into respiration and fermentation; however, recent work shows some species can use mixed or alternative bioenergetic strategies. We explored the use of extracellular electron transfer for energy conservation in diverse lactic acid bacteria (LAB), microorganisms that mainly rely on fermentative metabolism and are important in food fermentations. The LAB Lactiplantibacillus plantarum uses extracellular electron transfer to increase its NAD+/NADH ratio, generate more ATP through substrate-level phosphorylation, and accumulate biomass more rapidly. This novel, hybrid metabolism is dependent on a type-II NADH dehydrogenase (Ndh2) and conditionally requires a flavin-binding extracellular lipoprotein (PplA) under laboratory conditions. It confers increased fermentation product yield, metabolic flux, and environmental acidification in laboratory media and during kale juice fermentation. The discovery of a single pathway that simultaneously blends features of fermentation and respiration in a primarily fermentative microorganism expands our knowledge of energy conservation and provides immediate biotechnology applications.

Coastal salt marshes are distributed widely across the globe and are considered essential habitat for many fish and crustacean species. Yet, the literature on fishery support by salt marshes has largely been based on a few geographically distinct model systems, and as a result, inadequately captures the hierarchical nature of salt marsh pattern, process, and variation across space and time. A better understanding of geographic variation and drivers of commonalities and differences across salt marsh systems is essential to informing future management practices. Here, we address the key drivers of geographic variation in salt marshes: hydroperiod, seascape configuration, geomorphology, climatic region, sediment supply and riverine input, salinity, vegetation composition, and human activities. Future efforts to manage, conserve, and restore these habitats will require consideration of how environmental drivers within marshes affect the overall structure and subsequent function for fisheries species. We propose a future research agenda that provides both the consistent collection and reporting of sources of variation in small-scale studies and collaborative networks running parallel studies across large scales and geographically distinct locations to provide analogous information for data poor locations. These comparisons are needed to identify and prioritize restoration or conservation efforts, identify sources of variation among regions, and best manage fisheries and food resources across the globe.

In genetically heterogeneous mice produced by the CByB6F1 x C3D2F1 cross, the "non-feminizing" estrogen, 17-α-estradiol (17aE2), extended median male lifespan by 19% (p

Prochloron spp. are obligate cyanobacterial symbionts of many didemnid family ascidians. It has been proposed that the cyclic peptides of the patellamide class found in didemnid extracts are synthesized by Prochloron spp., but studies in which host and symbiont cells are separated and chemically analyzed to identify the biosynthetic source have yielded inconclusive results. As part of the Prochloron didemni sequencing project, we identified patellamide biosynthetic genes and confirmed their function by heterologous expression of the whole pathway in Escherichia coli. The primary sequence of patellamides A and C is encoded on a single ORF that resembles a precursor peptide. We propose that this prepatellamide is heterocyclized to form thiazole and oxazoline rings, and the peptide is cleaved to yield the two cyclic patellamides, A and C. This work represents the full sequencing and functional expression of a marine natural-product pathway from an obligate symbiont. In addition, a related cluster was identified in Trichodesmium erythraeum IMS101, an important bloom-forming cyanobacterium.

Seagrass meadows are among the most productive ecosystems in the marine environment. It has been speculated that much of this production is exported to adjacent ecosystems via the movements of organisms. Our study utilized stable isotopes to track seagrass-derived production into offshore food webs in the northeastern Gulf of Mexico. We found that gag grouper (Myctereoperca microlepis) on reefs as far as 90 km from the seagrass beds incorporate a significant portion of seagrass-derived biomass. The muscle tissue of gag grouper, a major fisheries species, was composed on average of 18.5-25% seagrass habitat-derived biomass. The timing of this annual seagrass subsidy appears to be important in fueling gag grouper egg production. The [delta].sup.34S values of gag grouper gonad tissues varied seasonally and were [delta].sup.34S depleted during the spawning season indicating that gag utilize the seagrass-derived biomass to support reproduction. If such large scale trophic subsidies are typical of temperate seagrass systems, then loss of seagrass production or habitat would result in a direct loss of offshore fisheries productivity., Author(s): James Nelson [sup.1] , Rachel Wilson [sup.1] , Felicia Coleman [sup.2] , Christopher Koenig [sup.2] , Doug DeVries [sup.3] , Chris Gardner [sup.3] , Jeff Chanton [sup.1] Author Affiliations: [...]

Am J Physiol Gastrointest Liver Physiol 298: G57-G62, 2010. First published November 5, 2009; doi: 10.1152/ajpgi.00175.2009.--To test the hypothesis that differences in duodenal iron absorption may explain the variable phenotypic expression among HFE C282Y homozygotes, we have compared relative gene expression of duodenal iron transporters among C282Y homozygotes [hereditary hemochromatosis (HH)] with and without iron overload. Duodenal biopsy samples were analyzed using real-time PCR for expression of DMT1, FPN1, DCYTB, and HEPH relative to GAPDH from 23 C282Y homozygotes, including 5 'nonexpressors' (serum ferritin < upper limit of normal and absence of phenotypic features of hemochromatosis) and 18 'expressors.' Four subjects of wild type for HFE mutations without iron overload or liver disease served as controls. There was a significant difference in expression of DMT1 (P = 0.03) and DMTI(IRE) (P = 0.0013) but not FPN1, DCYTB, or HEPH between groups. Expression of DMTI(IRE) was increased among HH subjects after phlebotomy compared with untreated (P = 0.006) and nonexpressor groups (P = 0.026). A positive relationship was observed among all HH subjects regardless of phenotype or treatment status between relative expression of FPN1 and DMT1 (r = 0.5854, P = 0.0021), FPN1, and DCYTB (r = 0.5554, P = 0.0040), FPN1 and HEPH (r = 0.5100, P = 0.0092), and DCYTB and HEPH (r = 0.5400, P = 0.0053). In summary, phlebotomy is associated with upregulation of DMTI(IRE) expression in HH subjects. HFE C282Y homozygotes without phenotypic expression do not have significantly decreased duodenal gene expression of iron transport genes compared with HH subjects with iron overload. There is coordinated regulation between duodenal expression of FPN1 and DMT1, FPN1 and DCYTB, and FPN1 and HEPH and also DCYTB and HEPH in HH subjects regardless of phenotype. iron homeostasis; duodenal iron transporters; hemochromatosis; HFE gene; DMT1; ferroportin; gene expression; iron absorption

The wheat leaf-rust resistance gene Lr21 was first identified in an Iranian accession of goatgrass, Aegilops tauschii Coss., the D-genome donor of hexaploid bread wheat, and was introgressed into modern wheat cultivars by breeding. To elucidate the origin of the gene, we analyzed sequences of Lr21 and h21 alleles from 24 wheat cultivars and 25 accessions of Ae. tauschii collected along the Caspian Sea in Iran and Azerbaijan. Three basic nonfunctional Ir21 haplotypes, HI, H2, and H3, were identilied. Lr21 was found to be a chimera of H1 and H2, which were found only in wheat. We attempted to reconstitute a functional Lr21 allele by crossing the cultivars Fielder (H1) and Wichita (H2). Rust inoculation of 5876 [F.sub.2] progeny revealed a single resistant plant that proved to carry the H1H2 haplotype, a result attributed to intragenic recombination. These findings retlect how plants balance the penalty and the necessity of a resistance gene and suggest that plants can reuse 'dead' alleles to generate new disease-resistance specificity, leading to a 'death-recycle' model of plant-resistance gene evolution at simple loci. We suggest that selection pressure in crop-weed complexes contributes to this process. DOI: 10.1534/genefics.108.099614

The comparison of organization of synapses reveal that different cell-cell adhesion proteins interact with networks of scaffolding proteins, the ctyoskeleton, and signaling pathways to regulate synapse and cell function.

The solid-phase synthesis of phenylacetylene oligomers which uses a nolvel 3-propyl-3-(benzyl-supported) triazene linkage is described. Phenylacetylene oligomers comprised of functionalized monomers are synthesized in gram quantities by solid-phase methods. The 1-aryl-3-propyl-3-(benzyl-supported) triazene moiety is used to attach growing oligomers to a divinylbenzene cross-linked polystyrene support, a linkage achieved by direct reaction of arenediazonium tetrafluoroborate salts with a n-propylamino-modified Merrifield resin. The yields and purities of oligomers obtained using this solid-phase method are compared with those of oligomers produced by solution methods.

A molecular-marker linkage map of hexaploid wheat (Triticum aestivum L. em. Thell) provides a framework for integration with the classical genetic map and a record of the chromosomal rearrangements involved in the evolution of this crop species. We have constructed restriction fragment length polymorphism (RFLP) maps of the A-, B-, and D-genome chromosomes of homoeologous groups 4, 5, and 7 of wheat using 114 F7 lines from a synthetic X cultivated wheat cross and clones from 10 DNA libraries. Chromosomal breakpoints for known ancestral reciprocal translocations involving these chromosomes/and for a known pericentric inversion on chromosome 4A were localized by linkage and aneuploid analysis. Known genes mapped include the major vernalization genes Vrn1 and Vrn3 on chromosome arms 5AL and 5DL, the red-coleoptile gene Rc1 on 7AS, and presumptively the leaf-rust (Puccinia recondita f.sp. tritici) resistance gene Lr34 on 7DS and the kernel-hardness gene Ha on 5DS. RFLP markers previously obtained for powdery-mildew (Blumeria graminis f.sp. tritici) resistance genes Pm2 and Pm1 were localized on chromosome arms 5DS and 7AL.

Analysis of the interaction between manganese (III) mesoporphyrin (MnMeso) and oleic acid (OA) vesicles reveals the preferential association of MnMeso with OA. Kinetic data suggest a binding stoichiometry of 1:3:4 between MnMeso and OA. Compared to egg phosphatidylcholine (EPC), OA induces higher increase of the Ti relaxation property of MnMeso. Interaction is stronger in OA-MnMeso than in PC-MnMeso. Electron microscopy helps confirm the association of MnMeso with the OA membrane.

The visible light-dependent changes in spectral absorption of marine phytoplankton detritus were studied. Laboratory results were compared to measurements of particulate spectral absorption, carbon and nitrogen obtained from waters with different optical characteristics. There was an increase in visible absorption following degradation of pigments. Bacterial spectral absorption was similar to detritus absorption. It was concluded that particulate spectral absorption is affected by the type and composition of particles, biological processing of organic matter and by photochemical processes.

Rtes, patterns and mechanisms of the degradation of phytoplankton and copepod fecal pellet pigments were determined. Chlorophylls, pheopigments and carotenoids were analyzed using high performance liquid chromatography. Experimental variables included light, aeration and presence of an active bacterial population. Results showed that pigment degradation was dependent on the presence of light and oxygen. Similar bleaching rates were observed for all pigments. It was suggested that a light-sensitive coupling mechanism exists between degradation pigments.

Bioethics education now takes place outside universities as well as within them. How should clinicians, ethics committee members, and policymakers be taught the ethics they need, and how may their [...]

Medical decisionmaking would be a messier but better thing if it honored what is morally valuable about patients' families. The concerns of intimates have a legitimate call upon us even [...]

Freud called it the 'romance of the family'--the fantasy that the grown-ups passing themselves off as your mother and father are impostors, and your 'real' family is not only much [...]

Estimates vary, but it seems safe to say that somewhere in the neighborhood of half of all deaths in America currently occur in hospitals. Many--perhaps most--Americans now spend their final [...]

Like many societies, our own has forged iron links between women's procreative capacity, the nurturing of children, and limitations on other forms of social expression and reward. Here as elsewhere, [...]

Of the many avenues opened for investigation by the push to facilitate advance care planning, two run along together like the lanes of a Los Angeles freeway. These are the [...]

Bioethical problems take many different forms, and fascinate many different kinds of people. Physicians and philosophers, lawyers and theologians, policy analysts and talk show hosts are all drawn by the [...]

The study explains the synthesis and characterization of SafC, a catechol 4-O-methyltransferase protein, which is commonly used for the biosynthesis of various saframycin products. SafC has the ability to methylate a variety of catechols and hence can be used in many medical and biological applications.

This distracted globe. The last Fellows meeting is scarcely a month past as I write these words, though it seems rather longer. Pace of life, perhaps, or maybe it's related [...]

Moral Particularism. Edited by Brad Hooker and Margaret Little, Oxford: Clarendon Press; New York: Oxford University Press, 2000, xiv+317 pp. $55 cloth, $19.95 paper. Reviewing is a tricky business. A [...]

When Doctors Say No: The Battleground of Medical Futility. By Susan B. Rubin. Bloomington & Indianapolis: Indiana University Press, 1998. 204 pp. $24.95. Roughly put, the phrase 'social constructionism' names [...]

Lessons for Bioethics from the Social Sciences and Managed Care Consider the following sketch of how bioethics relates to health care, its major object of study, and to the social [...]

By Christopher W. Gowans. New Yor: Oxford University Press, 1994. 257 pp. $39.95. A social worker of my acquaintance who chairs her hospital's ethics committee used to be continually depressed [...]

AM, an eighty-year-old woman, is brought by ambulance to the emergency room after an apparent suicide attempt. She was discovered by her neighbors, who have tried to look after her [...]

E.M. Forster's novel Howard's End might be seen as a parable of proxy decisionmaking that underscores the need for the sort of proposal Linda and Ezekiel Emanuel make. The book [...]

It's hardly startling that the store of bioethical essays concerned with the question, Who has the right to demand what from whom? dwarfs the supply of those that consider how [...]

Environmental ethics is sometimes characterized as moral intuitions in search of a theory; the feeling that nature is 'ethically considerable,' as current jargon puts it, is widespread but hard to [...]

Animal Experimentation: The Moral Issues. Edited by Robert M. Baird and Stuart E. Rosenbaum. Buffalo, N.Y: Prometheus Books, 1991. 182 pp. $14.95. Baird and Rosenbaum seem attracted to the tricky [...]