Prevalence of Giardia and Cryptosporidium species in dog park attending dogs compared to non-dog park attending dogs in one region of Colorado

Dog parks are very popular in urban areas, but there are no current studies attempting to correlate visits to dog parks and risk of colonization by enteric parasites. The purpose of this study was to determine whether dog park visitation is associated with an increased prevalence of enteric parasites or an increase in prevalence of gastrointestinal signs in dogs in northern Colorado. Feces from dogs owned by veterinary students or Veterinary Teaching Hospital staff members were submitted with a completed survey form detailing dog park attendance rates, fecal character scores, and other clinical information. Feces were examined microscopically for parasites after sugar centrifugation, for Giardia spp. cysts and Cryptosporidium spp. oocysts by a commercially available immunofluorescence assay (FA) and the FA positive samples were genotyped after PCR amplification. The Giardia assemblages were determined using the glutamate dehydrogenase (GDH) β-giardin and triose phosphate isomerase (TPI) genes and the Cryptosporidium species were determined using the heat shock protein-70 gene. A total of 129 fecal samples were assayed; 66 were from dog park attending dogs and 63 were from non-dog park-attending dogs. The overall parasite prevalence rate was 7.0% (9 of 129 samples). Dog park attending dogs were more likely to be positive for Giardia or Cryptosporidium than non-dog park-attending dogs (p=0.0279), but there was no association of gastrointestinal signs with dog park attendance or with fecal flotation or FA results. The five Giardia isolates were assemblage C and/or D and the one Cryptosporidium isolate was Ctenocephalides canis.     

Anti-chemokine activities of ixodid ticks depend on tick species,developmental stage,and duration of feeding

Ixodid ticks require comparatively large bloodmeals for their development and survival. Blood-feeding elicits signaling events in the host leading to wound healing responses (hemostasis, inflammation, and tissue repair) and immunity. Bioactive molecules present in tick saliva sabotage these host responses at several levels. One of them is neutralization of cellular communication by binding of specific saliva molecules to cytokines that have important roles in innate and adaptive immunity. Chemokines are a subset of cytokines having chemotactic activities. We show anti-chemokine activities in salivary gland extracts (SGE) of adult Rhipicephalus appendiculatus ticks against human chemokines CXCL8, CCL2, CCL3, CCL5, and CCL11. At comparable protein concentrations, male Ixodes ricinus SGE showed activity against all the chemokines; SGE of female I. ricinus had comparatively lower levels of activity against all the chemokines but no detectable activity against CCL5 and CCL11. However, when the equivalent of a single pair of salivary glands was tested, male I. ricinus showed little or no activity against CCL3 and CCL5. No fundamental differences in activity were observed against mouse compared with human chemokines. A comparison with previously published data for Dermacentor reticulatus and Amblyomma variegatum indicates that the level of anti-cytokine activity depends on the species, developmental stage (adult or nymph), and amount of SGE used, as well as on the number of days the tick has been feeding.     

Eco-physiological and Antioxidant Responses of Holm Oak (<Emphasis Type="Italic">Quercus ilex</Emphasis> L.) Leaves to Cd and Pb

Plants of the urban environment are exposed to a wide range of pollutants, including heavy metals. This research studies in situ the eco-physiological and antioxidant responses of holm oak (Q. ilex) leaves to Pb and Cd to assess the mechanisms of metal tolerance in this species, widely used as biomonitor. Leaves of plants grown at parks and roadsides were analyzed for photosynthetic activity, Pb and Cd concentration in tissues and cell-free extracts, thiol groups, D1 and Rubisco protein content, ascorbic acid (AsA) amount, and catalase (CAT) activity. The main results evidenced that Cd concentration was higher in leaves collected at the park out from the downtown; whereas Pb was most abundant in leaves sampled at the roadside nearby the highway. Pb in cell-free extracts was higher in park than in roadside leaves. Although Cd in the leaf tissues was twofold lower than Pb, it was more abundant than Pb in cellular extracts deprived of all particulate matter. Leaves responded to different concentration of Cd and Pb modulating some eco-physiological and biochemical traits, roadside leaves showed reduced leaf lamina, higher content of photosynthetic pigments, hydrogen peroxide, and AsA, as well as higher CAT activity compared to park leaves. In the roadside leaves, a stress condition for photosynthetic apparatus can be hypothesized on the basis of the decline of photochemical activity, the increase of NPQ, and the reduction of Rubisco and D1 protein content. The elevated presence of thiol groups in these leaves suggests a possible role of Pb and Cd in activation of antioxidant responses.     

The effects of invasive North American beavers on riparian plant communities in Cape Horn, Chile: Do exotic beavers engineer differently in sub-Antarctic ecosystems?

North American beavers (Castor canadensis) were introduced into southern South America in 1946. Since that time, their populations have greatly expanded. In their native range, beavers shape riparian ecosystems by selectively feeding on particular plant species, increasing herbaceous richness and creating a distinct plant community. To test their effects as exotic engineers on sub-Antarctic vegetation, we quantified beaver impacts on tree canopy cover and seedling abundance and composition, as well as their impacts on herbaceous species richness, abundance and composition on Navarino Island, Cape Horn County, Chile (55°S). Beavers significantly reduced forest canopy up to 30 m away from streams, essentially eliminating riparian forests. The tree seedling bank was greatly reduced and seedling species composition was changed by suppressing Nothofagus betuloides and Nothofagus pumilio, but allowing Nothofagus antarctica. Herbaceous richness and abundance almost doubled in meadows. However, unlike beaver effects on North American herbaceous plant communities, much of this richness was due to invasion by exotic plants, and beaver modifications of the meadow vegetation assemblage did not result in a significantly different community, compared to forests. Overall, 42% of plant species were shared between both habitat types. Our results indicate that, as predicted from North American studies, beaver-engineering increased local herbaceous richness. Unlike in their native range, though, they did not create a unique plant community in sub-Antarctic landscapes. Plus, the elimination of Nothofagus forests and their seedling bank and the creation of invasion pathways for exotic plants together threaten one of the world’s most pristine temperate forest ecosystems.     

Calorie restriction promotes mitochondrial biogenesis by inducing the expression of eNOS

Calorie restriction extends life span in organisms ranging from yeast to mammals. Here, we report that calorie restriction for either 3 or 12 months induced endothelial nitric oxide synthase (eNOS) expression and 3',5'-cyclic guanosine monophosphate formation in various tissues of male mice. This was accompanied by mitochondrial biogenesis, with increased oxygen consumption and adenosine triphosphate production, and an enhanced expression of sirtuin 1. These effects were strongly attenuated in eNOS null-mutant mice. Thus, nitric oxide plays a fundamental role in the processes induced by calorie restriction and may be involved in the extension of life span in mammals.     

Effects of humic acids and herbicides,and their combinations on the growth of tomato seedlings in hydroponics

The morphology and length of roots and shoots of tomato (Lycopersicon esculentum Mill.) seedlings grown on a nutrient medium for fourteen days in a controlled environment chamber were apparently not affected, whereas the dry matter content of roots was significantly enhanced when 200 mg L^?1 of humic acid (HA) isolated from either a non-amended soil or a sewage-sludge-amended soil was present in the nutrient medium. In contrast, the HA-like fraction isolated directly from the sewage sludge caused, under the same conditions, extensive alterations of tomato morphology and a significant reduction of the length and dry weight of both shoots and roots. The presence in the nutrient medium of the herbicides alachlor or imazethapyr at concentrations of 1 and 0.01 mg L^?1, respectively, caused a marked decrease of tomato root and shoot length and dry weight. Differently, the herbicide rimsulfuron at a concentration of 0.01 mg L^?1 produced a slight decrease in shoot and root length and a slight increase in their dry weight. A combination of 200 mg L^?1 soil HA and each of the herbicides alachlor, rimsulfuron and imazethapyr at concentrations of 1, 0.01 and 0.01 mg L^?1, respectively, in the nutrient medium attenuated the growth depression of tomato shoots and roots observed in the presence of the herbicide alone. However, the simultaneous presence of sewage sludge HA and any herbicide in the nutrient solution caused negative synergistic effects on tomato growth. The volume of nutrient solution and the amount of electrolytes taken up by tomato plants during the growth experiments correlated highly significantly with the total plant dry weight. Tomato seedlings induced a pH decrease in the nutrient medium in all treatments except in those where sludge-HA was present, either alone or in combination with any herbicide.     

Mechanical and water barrier properties of glutenin films influenced by storage time

The goal of this work was to study the effect of storage time on the functional properties of glutenin films plasticized with selected hydrophilic low molecular weight compounds: glycerol (GL), triethanolamine (TEA), and sorbitol (S). Glutenins were extracted from wheat gluten, and films were cast from film-forming solutions. The glutenin-based films were homogeneous, flexible, translucent, and easy to handle. Films were stored in an environmental chamber at 50 +/- 5% realtive humidity and 23 +/- 2 degrees C. Optical, mechanical, and water vapor permeability properties were monitored at regular intervals for 16 weeks. Films plasticized with GL and TEA had similar mechanical and water vapor barrier properties during the first few days of fabrication. Films plasticized with S were stronger, with better water vapor barrier properties. Mechanical and water vapor permeability properties of films plasticized with GL changed dramatically over time, whereas the properties of films plasticized with TEA and S remained stable during storage. Color properties of films plasticized with GL, TEA, and S did not change within the time period studied.     

Synthesis of antioxidants in wheat sprouts

Aqueous and ethanolic extracts from wheat (Triticum aestivum) sprout powder were analyzed to determine its reduction and antioxidant activities. Mean and standard deviation of five independent samples were reported. The results showed that the micromoles of potassium ferricyanide reduced by aqueous and ethanolic extracts corresponding to 1 g of sprout powder (80.6 +/- 11.2 and 9.7 +/- 1.8, respectively) were higher than that reduced by 1 mg of other reducing compounds: ascorbic acid, rutin, quercetin, and reduced gluthatione (4.8 +/- 0.7, 3.8 +/- 1.2, 4.8 +/- 1.7, and 1.6 +/- 0.4, respectively). In addition, the oxygen superoxide scavenging activity performed by sprout extracts (from 1 g of powder) is comparable to that shown by 10 mg of antioxidant pure compounds (rutin and quercetin). Biochemical analysis of the sprout extracts shows that the antioxidant activity is mainly due to reducing glycoside and polyphenolic compounds.