The amphibian chytrid fungus along an altitudinal transect before the first reported declines in Costa Rica

Amphibian populations have declined and disappeared in protected and apparently undisturbed areas around the world, especially in montane areas of the tropics. The amphibian chytrid fungus, Batrachochytrium dendrobatidis has been implicated in many of these declines. In Costa Rica most declines occurred in the highlands. We examined an amphibian collection made in Braulio Carrillo National Park in 1986 for the amphibian chytrid fungus B. dendrobatidis, prior to the well documented amphibian declines in Monteverde, along an altitudinal transect from 100 to 2600 m elev. Skin from the pelvic patch of 202 specimens corresponding to 30 species was examined histologically to determine whether the disease was present in the highlands of the park before amphibian populations declined. For comparison, in 2002 we collected and examined 18 specimens of seven species of Eleutherodactylus and Craugastor from two other lowland Caribbean sites. The chytrid fungus was present in almost all altitudes in 1986, including lower areas. The pathogen was also found in both species that later declined and in species that did not do so. We detected chytrid fungus on amphibians collected at almost all altitudes in 1986, including those sampled at 280 m. B. dendrobatidis was abundant in frogs collected in the 2002 survey, and seems to be endemic in most of Costa Rica. More retrospective museum surveys are needed in order to determine whether it can be found in the area before 1986.     

Direct and indirect evaluation of denudation rates in Central Italy

This paper presents the main results of a series of geomorphological studies, aimed to the quantitative direct and indirect evaluation of denudation processes in Central Italy. These studies, which started in some sample areas since long ago, were further deepened and extended to a wider number of drainage basins, representative of a variety of morphostructural conditions.     

Physicochemical behaviors of sugars, lipids, and gluten in short dough and biscuit

The structure of short dough and biscuit has been characterized at a macroscopic level (dimensions, bulk structure) and a microscopic level (starch damage, protein aggregates, microstructure) by physical and biochemical methods. The baking process of short dough induces a large decrease of the product bulk density from 1.26 to 0. 42 (+/-0.01) g.cm(-)(3) for final biscuit, leading to a cellular solid with a thin colored surface and a porous inner structure. Proteins appear aggregated in biscuit when compared to short dough, whereas starch granules remain almost intact in biscuits. The components which are involved in the cohesiveness of short dough and biscuit final structure have been identified. They suggest that short dough is a suspension of solid particles in a liquid phase being an emulsion of lipids in a concentrated sugar solution. The role of sugars in biscuit structure suggest that biscuit structure is a composite matrix of protein aggregates, lipids and sugars, embedding starch granules.     

Effect of the anion citrate on the mineral composition of artificial casein micelles

The composition of artificial casein micelles (ACM) prepared at constant concentration of caseins, calcium (Ca), and phosphate (P(i)) in media with different citrate (Cit) concentrations was studied. The incorporation of the different mineral and protein components to the ACM was conditioned by the Cit concentration. In our working condition, the ACM size remained almost constant for Cit concentration ranging from 7 to 10 mM. This behavior could be indicating that the action of Cit essentially consists of a regulation of the Ca activity. The molar ratio at which Ca and P(i) were incorporated to the ACM varied for different Cit concentrations. At decreasing pH, the Ca/P(i) molar ratios for the remanent ions in the ACM were dependent on the Cit concentration. These observations could be related to a certain kind of competition between Cit, micellar calcium phosphate (MCP), and other groups able to bind Ca in the ACM.     

Two microsatellite markers flanking a dominant gene for resistance to soybean cust nematode race 3

The purpose of this work was to identifymicrosatellite markers linked to a gene forresistance to Heterodera glycinesIchinohe (Soybean Cyst Nematode – SCN) insoybean cultivar Hartwig. ABC₁F₂ mapping population derivedfrom a cross between Hartwig (resistant)and the Brazilian soybean line Y23(susceptible) was used. About 200microsatellite or simple sequence repeat(SSR) primer pairs were tested in a bulkedsegregant analysis (BSA). Those thatshowed clear polymorphisms were amplifiedin the BC₁F₂ population, whichhad been previously inoculated andevaluated for resistance/susceptibility toSCN Race 3. Three SSR markers linked toSCN resistance were detected in thepopulation. Two of them, Satt 038 and Satt163, flanking a dominant resistant gene(d/a = –0.90), explained 37% of thephenotypic variance. This gene was mappedat the edge of molecular linkage group G. Broad and narrow sense heritabilities wereestimated to be 50.54% and 37.73%,respectively. A selection efficiency of91.18% was obtained with the simultaneoususe of the two markers. The identified SSRmarkers will be useful tools for assistingthe selection of homozygous genotypes andfor expediting the introgression of the SCNresistance locus from cv. Hartwig tosoybean elite cultivars.     

Digestive enzyme inhibitors and storage pest resistance in cowpea (Vigna unguiculata) seeds

Summary Amylase and trypsin inhibitors are proteins which inhibit digestive enzymes. The loss of the activity of these enzymes produces a reduction of starch and protein digestion. Amylase and trypsin inhibitor activity have been investigated in seeds of 20 cowpea lines in trying to establish their role in the storage pest resistance. A broad variation has been observed for both the inhibitors. Correlation analysis between inhibitor levels and extent of attack has shown that neither amylase nor trypsin inhibitors can separately explain the resistance to Callosobruchus maculatus (F.). Lines bruchid resistant in fact, have high levels of both inhibitors. Conversely lines with low levels of amylase and trypsin inhibitors are bruchid susceptible. The breeding for high contents of both amylase and trypsin inhibitors can be an effective way to obtain lines with resistance to storage pest.     

Identification and genetic characterization of an ethylene-dependent polygalacturonase from apricot fruit

During fruit ripening a loss of firmness occurs, which is a key factor limiting postharvest life. In apricot, Prunus armeniaca L., a wide range of fruit firmness at commercial maturity has been observed in different cultivars. Endopolygalacturonase (endoPG) activity has been reported to be associated with differences in firmness in many fruit species, but never in apricot. In this paper, we reported the identification of an apricot cDNA (PaPG) coding for an endoPG-like protein with 393 amino acids. Protein sequence comparison with known polygalacturonases (PGs) revealed that multiple features as conserved domains and functional residues and a predicted signal peptide were present in PaPG. Moreover, a phylogenetic analysis of this and other plant PGs placed PaPG into a clade containing endoPGs expressed in fruit, abscission and dehiscence zones without a propeptide sequence, very close to PRF5 from peach (Prunus persica L. Batsch). PaPG gene expression increased during postharvest storage of the fruit, correlating with fruit softening and ethylene release, and it responded to exogenous ethylene treatments. We localized the PaPG gene in apricot linkage group 4 after genetic mapping based on SNP analysis, in a position apparently syntenic to the PRF5 locus from peach. Results obtained offer genetic evidence supporting the hypothesis that PaPG and PRF5 are orthologous genes, and consequently position PaPG as a gene of interest for studies on fruit softening in apricot, and contribute to the development of molecular tools for breeding apricots with longer shelf life.     

Dampened behavioral and physiological responses mediate birds’ association with humans

The study of the mechanisms involved in phenotypic adaptations or plasticity to environmental stressors may serve to evaluate contemporary ecological and evolutionary dynamics in threatened or growing wildlife populations. By addressing human disturbance as a main stressor agent, we investigated antipredator response (flushing distance), social behavior (degree of gregarism), health (fecal pathogens), and endocrine status (fecal corticosterone levels) as potential mechanisms that permit birds to cope with anthropogenic impact in tourist areas. Our study models were species that are neither urbanized nor invasive, and that are typical of the high mountains of the Palearctic: the Alpine and the Red-billed chough (Pyrrhocorax graculus and P. pyrrhocorax), and the surrounding alpine bird community. Both chough species showed habituation, reduced flushing distances, fewer parasites and lower corticosterone levels in tourist than in non-tourist sites, and a significant variation in gregarious behavior. Behavioral and physiological adjustments permitted these corvids to optimize resource exploitation depending on habitat quality and in conditions of continuous disturbance. Human-induced changes in chough social behavior had no effect on local avian species richness, a surrogate measure for community diversity. Irrespectively of chough aggregations, bird diversity decreased significantly in recreational areas, thus not all community members tolerated human impact as choughs did. Our findings suggest that species that manage to coexist with humans primarily adjust traits that influence ecological interactions (social, foraging or antipredatory responses) and that vary rapidly (learned behaviors and physiological mechanisms that promote homeostasis).     

Corneal ulceration in a dog following exposure to the defensive spray of a walkingstick insect (Anisomorpha spp.)

Objective – To describe a case of corneal ulceration in a dog resulting from ocular exposure to the defensive spray of a walkingstick insect (Anisomorpha spp.). Case Summary – A 4‐year‐old, male Chihuahua in southeastern Louisiana presented to an emergency veterinary hospital approximately 20 hours after it was witnessed to have come in close proximity to a walkingstick insect. Within seconds of approaching the insect, the dog yelped, jumped backwards and developed lacrimation, blepharospasm, and periocular swelling of the left eye. Upon presentation, the dog was found to have blepharospasms and miosis of the left eye. Fluorescein stain was applied to the affected eye and diffuse corneal uptake of stain was noted. A diffuse superficial corneal ulceration was diagnosed and treated supportively with ocular flushing, topical antibiotics, ocular lubrication, and a 1% solution of ocular atropine, as well as systemic nonsteroidal anti‐inflammatory agents. Clinical signs resolved 10 days after injury. New or Unique Information Provided – While most species of walkingstick insects are considered harmless, certain species in the southeastern United States have the ability to spray defensive venom at their predators. Upon ocular exposure to the venom, the victim may experience intense pain followed by blurred vision, conjunctivitis, keratitis, and corneal ulceration. To date, there is only 1 previous reported case of ocular exposure to walkingstick venom in a dog although both children and animals may be at higher risk for ocular exposure due to their curious nature and proximity in size to the insect. Superficial corneal and conjunctival damage can occur following direct exposure to the defensive chemical spray of the Northern and Southern Twostriped walkingstick insects found in the southeastern United States and may be considered a differential diagnosis in cases involving diffuse corneal ulceration.     

Fruit thinning in ‘Conference’ pear grown under deficit irrigation: Implications for fruit quality at harvest and after cold storage

Fruit thinning in pear is feasible for mitigation of water stress effects. However, it is not well known how fruit quality at harvest and after cold storage is affected by pre-harvest water stress. Even less is known about the effects of fruit thinning on quality under these circumstances. To elucidate these, we applied deficit irrigation (DI) and fruit thinning treatments to ‘Conference’ pear over the growing seasons of 2008 and 2009. At the onset of Stage II (80 and 67 days before harvest in 2008 and 2009, respectively), two irrigation treatments were applied: full irrigation (FI) and DI. FI trees received 100% of crop evapotranspiration (ETc). DI trees received no irrigation during the first three weeks of Stage II to induce water stress, but then received 20% of ETc to ensure tree survival. From bud-break until the onset of Stage II and during post-harvest, FI and DI trees received 100% of ETc. Each irrigation treatment received two thinning levels: no thinning leaving commercial crop load (∼180 fruits tree⁻¹), and hand-thinning at the onset of Stage II leaving a light crop load (∼85 fruits tree⁻¹). Under commercial crop loads, DI trees were moderately water-stressed and this had some positive effects on fruit quality. DI increased fruit firmness (FF), soluble solids concentrations (SSC) and acidity at harvest while no changes were observed in fruit maturity (based on ethylene production). Differences in FF and acidity at harvest between FI and DI fruit were maintained during cold storage. DI also reduced fruit weight loss during storage. But fruit size was reduced under DI. Fruit thinning under DI resulted in better fruit composition with no detrimental effect on fresh-market yield compared to un-thinned fruit. Fruit size at harvest and SSC values after five months of cold storage were higher in fruit from thinned trees than fruit from un-thinned trees. Fruit thinning increased fruit ethylene production, indicating advanced maturity. This may lead to earlier harvest which is desirable in years with impending drought. Fruit thinning is therefore a useful technique to enhance pear marketability under water shortage.