Enzymatic Recovery of Elemental Palladium by Using Sulfate-Reducing Bacteria

Worldwide usage of platinum group metals is increasing, prompting new recovery technologies. Resting cells of Desulfovibrio desulfuricans reduced soluble Pd²⁺ to elemental, cell-bound Pd⁰ supported by pyruvate, formate, or H₂ as the electron donor without biochemical cofactors. Pd reduction was O₂ insensitive, opening the way for recycling and recovery of Pd under oxic conditions.     

Comprehensive label-free method for the relative quantification of proteins from biological samples

Pharmaceutical companies and regulatory agencies are broadly pursuing biomarkers as a means to increase the productivity of drug development. Quantifying differential levels of proteins from complex biological samples such as plasma or cerebrospinal fluid is one specific approach being used to identify markers of drug action, efficacy, toxicity, etc. We have developed a comprehensive, fully automated, and label-free approach to relative protein quantification from LC-MS/MS experiments of proteolytic protein digests including: de-noising, mass and charge state estimation, chromatographic alignment, and peptide quantification via integration of extracted ion chromatograms. Results from a variance components study of the entire method indicate that most of the variability is attributable to the LC-MS injection, with a median peptide LC-MS injection coefficient of variation of 8% on a ThermoFinnigan LTQ mass spectrometer. Spiked recovery results suggest a quantifiable range of approximately 32-fold for a sample protein.     

The effects of nectar addition on pollen removal and geitonogamy in the non-rewarding orchid Anacamptis morio

It has been suggested that the absence of floral rewards in many orchid species causes pollinators to probe fewer flowers on a plant, and thus reduces geitonogamy, i.e. self-pollination between flowers, which may result in inbreeding depression and reduced pollen export. We examined the effects of nectar addition on pollinator visitation and pollen transfer by tracking the fate of colour-labelled pollen in Anacamptis morio, a non-rewarding orchid species pollinated primarily by queen bumble-bees. Addition of nectar to spurs of A. morio significantly increased the number of flowers probed by bumble-bees, the time spent on an inflorescence, pollinarium removal and the proportion of removed pollen involved in self-pollination through geitonogamy, but did not affect pollen carryover (the fraction of a pollinarium carried over from one flower to the next). Only visits that exceeded 18 s resulted in geitonogamy, as this is the time taken for removed pollinaria to bend into a position to strike the stigma. A mutation for nectar production in A. morio would result in an initial 3.8-fold increase in pollinarium removal per visit, but also increase geitonogamous self-pollination from less than 10% of pollen depositions to ca. 40%. Greater efficiency of pollen export will favour deceptive plants when pollinators are relatively common and most pollinaria are removed from flowers or when inbreeding depression is severe. These findings provide empirical support both for Darwin's contention that pollinarium bending is an anti-selfing mechanism in orchids and for the idea that floral deception serves to maximize the efficiency of pollen export.     

Hipposin,a histone-derived antimicrobial peptide in Atlantic halibut (Hippoglossus hippoglossus L.)

A novel 51-residue antimicrobial peptide (AMP) from the skin mucus of Atlantic halibut (Hippoglossus hippoglossus L.) was isolated using acid extraction, and cationic exchange and reversed phase chromatography. The complete amino acid sequence of the AMP, termed hipposin, was determined by automated Edman degradation and mass spectrometry to be SGRGKTGGKARAKAKTRSSRAGLQFPVGRVHRLLRKGNYAHRVGAGAPVYL. The N-terminal amino group was acetylated. The theoretical mass of hipposin was calculated to be 5458.4 Da, which was in good agreement with the mass of 5459 Da determined by matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS). Hipposin was shown to be derived from histone H2A by PCR amplifying the encoding sequences from Atlantic halibut genomic DNA. The peptide showed sequence similarity with the 39-mer AMP buforin I of Asian toad and the 19-mer AMP parasin I of catfish. Fifty of the fifty-one residues in hipposin were identical to the N-terminal region of histone H2A from rainbow trout. Hipposin showed strong antimicrobial activity against several Gram-positive and Gram-negative bacteria and activity could be detected down to hipposin concentrations of 0.3 microM (1.6 microg/ml). Hipposin without N-terminal acetylation was prepared by solid-phase peptide synthesis and shown to have the same antimicrobial activity as the natural acetylated peptide. Thus, hipposin is a new broad-spectrum histone-derived AMP found in the skin mucus of Atlantic halibut.     

Effects of acorn masting on population dynamics of three forest-dwelling rodent species in Hokkaido,Japan

The effects of the abundance of acorns of the oak, Quercus crispula, on the population dynamics of three rodent species (Apodemus speciosus, A. argenteus, and Clethrionomys rufocanus) were analyzed using time series data (1992–2006). The data were obtained in a forest in northern Hokkaido, Japan, by live trapping rodents and directly counting acorns on the ground. Apodemus speciosus generally increased in abundance following acorn masting. However, the clear effect of acorn abundance was not detected for the other two rodent species. Acorns of Q. crispula contain tannins, which potentially have detrimental effects on herbivores. Apodemus speciosus may reduce the damage caused by acorn tannins with tannin-binding salivary proteins and tannase-producing bacteria, whereas such physiological tolerance to tannins is not known in the other two rodent species. The differences in the effects of acorns between the three species may be due to differences in their physiological tolerance to tannins.     

Increased bioethanol production from commercial tobacco cultivars overexpressing thioredoxin f grown under field conditions

Bioethanol is mainly produced from food crops such as sugar cane and maize, and this has been held partly responsible for the rise of food commodity prices. Tobacco, integrated in biorefinery facilities for the extraction of different compounds, could become an alternative feedstock for biofuel production. When grown for energy production, using high plant densities and several mowings during the growing season, tobacco can produce large amounts of inexpensive green biomass. We have bred two commercial tobacco cultivars (Virginia Gold and Havana 503B) to increase the carbohydrate content by the overexpression of thioredoxin f in the chloroplast. Marker-free transplastomic plants were recovered and their agronomic performance under field conditions was evaluated. These plants were phenotypically equivalent to their wild types yet showed increased starch (up to 280 %) and soluble sugar (up to 74 %) contents in leaves relative to their control plants. Fermentable sugars released from the stalk were also higher (up to 24 %) for transplastomic plants. After heat pretreatment, enzymatic hydrolysis and yeast fermentation of leaf and stalk hydrolysates, an average of 20–40 % more ethanol was obtained from transplastomic plants than their wild-type controls. We propose an integral exploitation of the entire tobacco plant managed as a forage crop (harvesting sugar and starch-rich leaves and lignocellulosic stalks) that could considerably cheapen the entire production process.     

The embryo culture media in the era of epigenetics: is it time to go back to nature?

This review is intended to draw attention to the importance of the culture media composition on the health of the embryos, fetuses, newborns, and adults derived from assisted reproductive technologies (ART). Although current research and industry trends are to use chemically defined media because of their suitability for manufacturing, commercialization, and regulatory purposes, compelling evidence indicates that those media fail to adequately account for the biological demands of early embryogenesis. Here, we list the main undesirable consequences of the ART described in the literature and results we and others have obtained over the past decade exploring an alternative and more natural way to support embryo growth in vitro: inclusion of endogenous reproductive fluids as additives in the ART culture media for pigs, cows, and humans. This review systematically assesses the pros and cons of using reproductive fluid additives, as well as the requirements to implement this approach in the future.     

Observations of bioluminescence in marine plankton from the Sea of Cortez

A bioluminescence chemical oceanography research cruise (Varifront III) through the Sea of Cortez from November through December 1981 provided an opportunity to investigate plankton associated with a brilliant and extensive display of surface water bioluminescence at the north end of Balleñas Channel. New observations of bioluminescence were made on larval stages of the euphausiid Nyctiphanes simplex Hansen (Calyptopis II, Furcilia I, II, and III, and juveniles) and Euphausia eximia Hansen (Calyptopis I), the Calanoida copepods Centropages furcatus Dana, Paracalanus indiens Wolfenden, Acrocalanus longicornis Giesbrecht, the Cyclopoida copepods Corycaeus (Corycaeus) speciousus Dana, Corycaeus (Onychocorycaeus) latus Dana, and several dinoflagellates Ceratium breve Ostenfeld and Schmidt, Ceratium horridum Gran, and Ceratium gibberum Gourret. These observations indicate the increasing importance of some of the smaller copepods and larval euphausiids contributing to surface bioluminescence.     

Functional characteristics of dystrophic skeletal muscle: insights from animal models.

Muscular dystrophies are a clinically and genetically heterogeneous group of disorders that show myofiber degeneration and regeneration. Identification of animal models of muscular dystrophy has been instrumental in research on the pathogenesis, pathophysiology, and treatment of these disorders. We review our understanding of the functional status of dystrophic skeletal muscle from selected animal models with a focus on 1) the mdx mouse model of Duchenne muscular dystrophy, 2) the Bio 14.6 delta-sarcoglycan-deficient hamster model of limb-girdle muscular dystrophy, and 3) transgenic null mutant murine lines of sarcoglycan (alpha, beta, delta, and gamma) deficiencies. Although biochemical data from these models suggest that the dystrophin-sarcoglycan-dystroglycan-laminin network is critical for structural integrity of the myofiber plasma membrane, emerging studies of muscle physiology suggest a more complex picture, with specific functional deficits varying considerably from muscle to muscle and model to model. It is likely that changes in muscle structure and function, downstream of the specific, primary biochemical deficiency, may alter muscle contractile properties.