Fossil evidence for evolution of the shape and color of penguin feathers

Penguin feathers are highly modified in form and function, but there have been no fossils to inform their evolution. A giant penguin with feathers was recovered from the late Eocene (~36 million years ago) of Peru. The fossil reveals that key feathering features, including undifferentiated primary wing feathers and broad body contour feather shafts, evolved early in the penguin lineage. Analyses of fossilized color-imparting melanosomes reveal that their dimensions were similar to those of non-penguin avian taxa and that the feathering may have been predominantly gray and reddish-brown. In contrast, the dark black-brown color of extant penguin feathers is generated by large, ellipsoidal melanosomes previously unknown for birds. The nanostructure of penguin feathers was thus modified after earlier macrostructural modifications of feather shape linked to aquatic flight.     

Wild halophytic species as forage sources: Key aspects for plant breeding

The use of wild halophytic species as forage resources in saline environments has gained increasing attention. Argentina ranks third in area of saline soils in the world, with a third of its territory showing various degrees of salinity, sodicity and/or alkalinity. On this type of soils, rangelands are the main forage resource for livestock production. Many wild species have forage potential and can also be used for the rehabilitation of rangelands and for intercropping. Information about these species, as well as on the physiological and genetic bases associated with salinity tolerance, provides relevant tools for efficient selection methods. This study addresses Argentine wild halophyte species with forage potential and describes selection criteria with an emphasis on the following taxa: (a) Poaceae: subfamily Chloridoideae and tribes Paniceae and Triticeae, (b) Fabaceae and (c) Amaranthaceae (formerly known as Chenopodiaceae). The review is intended to contribute to the general discussion on strategies for the improvement of wild plant genetic resources, using forage species naturally growing in saline soils in Argentina as a case study.     

Geographic variability in response to azinphos‐methyl in field‐collected populations of Cydia pomonella (Lepidoptera: Tortricidae) from Argentina

BACKGROUND: Resistance to insecticides has been related to application history, genetic factors of the pest and the dynamic within the treated area. The aim of this study was to assess the geographic variation in azinphos‐methyl response and the role of esterase and cytochrome P450 monooxygenase enzymes in codling moth populations collected within different areas of the Río Negro and Neuquén Valley, Argentina. RESULTS: Diapausing field‐collected populations showed resistance ratios at the LC₅₀ that were 0.7–8.7 times higher than that of the susceptible strain. Mean esterase (EST) and cytochrome P450 monooxygenase activities (expressed as α‐N min^?1 mg^?1 prot^?1 and pg 7‐OHC insect^?1 min^?1 respectively) were significantly correlated with LD₅₀ values from the field‐collected populations. In addition, azinphos‐methyl response was associated with the geographic area where the insect population was collected: populations from isolated and more recent productive areas presented significantly lower resistance ratios in comparison with populations from older and more intensive productive areas. CONCLUSION: The populations assayed presented different resistance levels to azinphos‐methyl. The response was highly correlated with the orchard's geographic location. EST and ECOD activities were involved in azinphos‐methyl response in the given region. Copyright © 2012 Society of Chemical Industry     

Toxicity of seawater and sand affected by the Prestige fuel-oil spill using bivalve and sea urchin embryogenesis bioassays

An evaluation of the toxicity of seawater and sand sampled from an area of the Galician coast (NW Iberian Peninsula), highly impacted by the Prestige fuel-oil spill, was attempted by using marine invertebrate embryogenesis bioassays with bivalves and sea urchins. Water samples were frozen and toxicity testing was delayed until the reproductive season of the sea urchins. Sand samples were elutriated and tested within 13 d from sampling, using bivalves from commercial stocks. Sand elutriates were non toxic for embryos despite visual presence of small tar balls. In contrast, seawater from the most impacted site was highly toxic during the first days after the spill, with complete inhibition of embryogenesis even after 4-fold dilution. In a lower degree toxicity persisted for two months in light-exposed coastal water. These findings stress the impact to water column organisms of the less conspicuous and frequently overlooked water-accommodated fraction, rather than the more visible oil slick.     

Identification of mtDNA lineages of Sus scrofa by multiplex single base extension for the authentication of processed food products

A genetic method to identify the breed of origin could serve as a useful tool for inspecting the authenticity of the increasing number of monobreed foodstuffs, such as those derived from small local European pig breeds. Mitochondrial DNA (mtDNA) is practically the only reliable genomic target for PCR in processed products, and its haploid nature and strict maternal inheritance greatly facilitate genetic analysis. As a result of strategies that sought to improve the production traits of European pigs, most industrial breeds presently show a high frequency of Asian alleles, while the absence or low frequency of such Asian alleles has been observed in small rustic breeds from which highly prized dry-cured and other traditional products are derived. Therefore, the detection of Asian ancestry would indicate nonconformity in Protected Denomination of Origin products. This study presents a single base extension assay based on 15 diagnostic mtDNA single nucleotide polymorphisms to discriminate between Asian and European Sus scrofa lineages. The test was robust, sensitive and accurate in a wide range of processed foodstuffs and allowed accurate detection of pig genetic material and identification of maternal ancestry. A market survey suggested that nonconformity of products derived from Portuguese breeds is an unusual event at present, but regular surveys both in the local populations and in commercial products would be advisible. Taking into consideration the limitations presented by other methodologies, this mtDNA-based test probably attains the highest resolution for the direct genetic test for population of origin in Sus scrofa food products.     

Blood gas analysis and cooximetry in retired racing Greyhounds

Objective – The purposes of this study were to evaluate the oxygen affinity of hemoglobin (Hb) in healthy retired racing Greyhounds via cooximetry, and to establish reference intervals for blood gases and cooximetry in this breed. Design – Prospective clinical study. Setting – University Teaching Hospital. Animals – Fifty‐seven Greyhounds and 30 non‐Greyhound dogs. Interventions – Venous blood samples were collected from the jugular vein and placed into heparinized tubes. The samples were analyzed within 30 minutes of collection using a blood gas analyzer equipped with a cooximeter. Measurements and Main Results – Greyhounds had significantly higher pH, PO₂, oxygen saturation, oxyhemoglobin, total Hb, oxygen content, and oxygen capacity and significantly lower deoxyhemoglobin and P₅₀ when compared with non‐Greyhound dogs. Conclusion – These findings support the fact that this breed is able to carry a higher concentration of total oxygen in the blood. As reported previously, this breed also has lower P₅₀ and, therefore, high oxygen affinity. In light of recent findings suggesting that in certain tissues a high affinity for oxygen is beneficial, this adaptation may be of benefit during strenuous exercise.     

Fate of prions in soil: Interaction of a recombinant ovine prion protein with synthetic humic-like mineral complexes

Prion proteins are regarded as the main agents of transmissible spongiform encephalopathies. Understanding their fate in soil may be crucial to elucidate the dissemination of the prion in the environment, associated with a possible transmission of infectivity. Studies were performed with simplified model systems, derived by the birnessite-mediated oxidative polymerization of catechol, which simulate processes naturally occurring in soil. A benign full-length recombinant purified ovine protein (PrP) (residues 23-234), as well as a truncated-form ovPrP (tPrP) (103-234) were utilized. Catechol and prion protein interacted under experimental conditions that reproduced the interaction of PrP with soluble organic matter or with insoluble organic matter during or after formation of catechol polymers. PrP stability in all buffers and chemicals was preliminarily monitored by circular dicroism (CD) measurements. The disappearance of protein molecules from the solution, the decrease of UV-Visible absorbance of supernatants, and the FT-IR spectra and the elemental analyses of solid-phase residues indicated that both PrP and tPrP were involved in catechol polymerization by birnessite. Furthermore, a clear flocculation of soluble catechol-protein polymeric products in solid aggregates was observed when PrP was added to the supernatants. Different kinds of extracting agents were not able to desorb/extract PrP as well as tPrP from the formed solid aggregates, thereby highlighting the high stability of protein-organic and -organo-mineral complexes.     

An effective field screening method for flood tolerance in soybean

Flooding is an abiotic stress that causes considerable reductions in crop growth and yield worldwide. Soybean (Glycine max [L.] Merr.) cultivars are generally sensitive to flooding stress. The objective of this study was to develop an effective flooding tolerance screening method in the field. A total of 40 soybean genotypes were evaluated for flooding tolerance at V5 and R1 growth stages. At each stage, genotypes were exposed to different durations of flooding stress (3, 6, 9, 12 and 15 days). Plant foliar damage score (FDS) and plant survival rate (PSR) were used as the indicators of flooding tolerance. Soybeans were more sensitive to flooding at R1 growth stage than V5 growth stage. Length of flooding duration accounted for the variance of FDS and PSR. Soybean genotypes exposed to a 3‐day flooding in either V5 or R1 growth stage, did not show obvious foliar damage, while genotypes exposed to a 12‐ or 15‐day flooding showed significant foliar damage and plant death. The optimum flooding duration to screen for flooding tolerance in the field was determined to be 9 and 6 days for V5 and R1 growth stages, respectively, as distinguishable responses to flooding allowed genotypes to be classified as either being flooding tolerant or flooding sensitive. High correlation between FDS and PSR (.99, p < .0001) was observed. Similarly, FDS and PSR were highly correlated with grain yield (.95 and .95, p < .0001). The field screening method for flooding tolerance developed in our study will be favourable for selection of soybean flooding‐tolerant germplasm.