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721.
We evaluate the ecological sustainability of extracting the oleoresin of Copaifera multijuga Hayne and some factors influential in its production. We monitored oleoresin production after initial extraction in 43 mother trees in the Adolpho Ducke Forest Reserve, near Manaus, Brazil (2°57′43″ S, 59°55′38″ W). We evaluated production relative to tree diameter (DBH), collection interval, soil clay content, competition intensity, and termite infestation. 57% of productive trees had DBH ≥ 41 cm and were responsible for 95% of total production. Although these trees had the highest initial production, after one year only 28% of initial oleoresin production was recuperated, much slower than in trees with DBH < 41 cm. Production was positively correlated with DBH and dominance within mother tree. Oleoresin production varied slightly with season. Trees that never produced oleoresin did not have termite infestations.  相似文献   
722.
Methylxanthinic alkaloids and phenolic compounds are related to the therapeutic properties of Ilex paraguariensis infusions. Considering the known vascular tropism of xanthines, an aqueous extract (mate) and caffeine were evaluated on blood vessel formation, in connection with the analysis of those secondary metabolites, which was performed in young and mature leaf samples collected in three cultivation systems located in the southern region in Brazil (Santa Catarina State). Samples of young and mature leaves from a monoculture cultivation system (MC) showed the highest content of phenolic compounds (149.68 microg/mL, young leaves; 135.50 microg/mL, mature leaves) and caffeine (young leaves, 148.07 microg/mL; mature leaves, 244.63 microg/mL) as compared to samples from agroforesty (AF) and shaded-native (NT) cultures. Theophylline was not detected in samples by reverse phase-high performance liquid chromatography, and mature leaves showed lower theobromine amounts (11.46 microg/mL). Treatments performed with mate aqueous extract and caffeine (1.03-4.12 microM/disk) in the yolk sac vascular membranes of 2-day-old chick embryos revealed pro-vasculo- and angiogenic properties as well as embryonic growth enhancement. These findings, uncoupled from any detectable embryotoxic effect, suggest a potential therapeutic and/or prophylactic use in cardiovascular disorders for caffeine and related constituents of mate plant extracts, an issue that waits further studies.  相似文献   
723.
This study was designed to optimize calcium-45 (45Ca) sample preparation method in a Liquid Scintillation Counter (LSC) for use with vegetables and soil samples. Different tests were conducted on fruit and soil samples to determine the best conditions related to drying, time and centrifuge speed (rpm) after calcination at 450°C and 550°C for vegetable and soil samples, respectively. The homogeneity of samples, linearity, detection and quantification limits were also determined. The quench curve was calculated to establish the parameters to program the LSC. Six 45Ca sample replicates were measured with a coefficient of variation (CV) of 1.74%, which indicates good sample homogeneity. The method is linearity over the range of activity studied for 0–30,000 disintegrations per minute (dpm). Our results suggest that the optimum homogenized sample preparation for calcination purposes was lyophilization. Techniques using 45Ca applied to soil and plant tissues are promising tracers of Ca in plants, which can be very useful for the study of Ca kinetics in plants and can serve to guide efficient fertilization programs.  相似文献   
724.
The exposure of pigs to heat stress (HS) appears to damage their intestinal epithelia, affecting the absorption of amino acids (AAs). Arg is involved in the restoration of intestinal epithelial cells but HS reduces Arg intake. The effect of dietary supplementation with Arg on the morphology of intestinal epithelia, AA transporter gene expression, and serum concentration (SC) of free AAs in HS pigs was analyzed. Twenty pigs (25.3 ± 2.4 kg body weight) were randomly assigned to two dietary treatments: Control (0.81% Arg), wheat–soybean meal diet supplemented with l-Lys, l-Thr, dl-Met, and l-Trp, and the experimental diet where 0.16% free l-Arg was supplemented to a similar Control diet (+Arg). All pigs were individually housed and exposed to HS, fed ad libitum with full access to water. The ambient temperature (AT), recorded at 15-min intervals during the 21-d trial, ranged on average from 29.6 to 39.4 °C within the same day. Blood samples were collected on day 18 at 1600 hours (AT peak); serum was separated by centrifugation. At the end of the trial, five pigs per treatment were sacrificed to collect samples of mucosa scratched from each small intestine segment. The expression of AA transporters in intestinal mucosa and the SC of AAs were analyzed. Villi height (VH) was higher (P < 0.01) in the duodenum, jejunum, and ileum but the crypt depth did not differ between the Control and the +Arg pigs. Supplementation of l-Arg increased the mRNA coding for the synthesis of the cationic AA transporter b0,+ (P < 0.01) and the neutral AA transporter B0 (P < 0.05) in the duodenum by approximately 5-fold and 3-fold, respectively, but no effect on mRNA abundance was observed in the jejunum and ileum. The supplementation of l-Arg increased serum Arg, His, Met, Thr, Trp, and urea (P < 0.05) and also tended to increase Val (P < 0.10) but did not affect Ile, Lys, Leu, and Phe. These results indicate that supplementing 0.16% l-Arg to the Control diet may help to improve the function of the small intestine epithelium, by increasing the VH, the abundance of AA transporters, and the SC of most indispensable AAs in pigs exposed to HS conditions. However, the lack of effect of supplemental Arg on both Lys SC and weight gain of pigs suggests that increasing the Lys content in the +Arg diet might be needed to improve the performance of HS pigs.  相似文献   
725.
Although silicon (Si) is not an essential element, it presents a close relationship with the alleviation of heavy‐metal toxicity to plants. This work was carried out to evaluate the effects of Si application to soil on the amelioration of metal stress to maize grown on a contaminated soil amended with Si (0, 50, 100, 150, and 200 mg kg–1) as calcium silicate (CaSiO3). Additionally, the cadmium (Cd) and zinc (Zn) bioavailability as well as their distribution into soil fractions was also studied. The results showed that adding Si to a Cd‐ and Zn‐contaminated soil effectively diminished the metal stress and resulted in biomass increase in comparison to metal‐contaminated soil not treated with Si. This relied on Cd and Zn immobilization in soil rather than on the increase of soil pH driven by calcium silicate application. Silicon altered the Cd and Zn distribution in soil fractions, decreasing the most bioavailable pools and increasing the allocation of metals into more stable fractions such as organic matter and crystalline iron oxides.  相似文献   
726.
Tick-transmitted rickettsial pathogens belonging to the Ehrlichia and Anaplasma genera can infect dogs and humans. In this study, four dogs from the North of Portugal, in which an ehrlichial disease was suspected clinically, were tested by molecular methods. After DNA extraction from blood on filter paper, a 345 bp fragment of the Ehrlichia/Anaplasma 16S rRNA gene was amplified by the polymerase chain reaction (PCR). Sequence analysis of PCR products revealed one dog infected with Ehrlichia canis and three with Anaplasma platys. One of these latter animals was co-infected with Babesia canis subspecies vogeli. This is the first report of the genetic characterisation of both A. platys and E. canis in naturally infected dogs from the North of Portugal.  相似文献   
727.
728.
Canine shelters frequently have inadequate living conditions that affect the behavior of dogs. This study compared fear-appeasement and sociability reactions in shelter and pet dogs when they are confronted by an unfamiliar experimenter. Results indicated that shelter dogs used for this study showed more fear-appeasement behavior—tail down, ears down, and crouching—as compared with pet dogs. In addition, shelter dogs quite frequently remained closer to the individual, despite showing signs of fear-appeasement, as compared with pet dogs. Finally, shelter dogs remained near the door of the enclosure less often when compared with pet dogs. This difference might be accounted for by the lack of any attachment bonds among shelter dogs toward their caretakers. These results may be associated to the usual stressful conditions and limited interactions with human beings that may be observed in shelters with scarce resources.  相似文献   
729.
730.
A collection of 70 olive samples, originating from diverse areas in central-southern Italy (Abruzzo, Apulia, Calabria, and Umbria) and corresponding to 3 major cultivars denominations (‘Carolea’, ‘Coratina’ and ‘Frantoio’), was genotyped at 10 microsatellite loci. In total, 44 alleles with a mean number of 4.4 alleles per locus were detected. The molecular analysis, allowed the study to show a clear genetic diversity between the three cultivars ‘Carolea’, ‘Coratina’ and ‘Frantoio’ and to state that ‘Carolea’ is a polyclonal cultivar, while ‘Coratina’ and ‘Frantoio’, are probably monoclonal ones. The analysis of intra-varietal polymorphism, through the SSR analysis, proved to be very useful both for varietal identification and for intra-varietal ones. Our work shows that the current designations of olive cultivars fall short of describing the genetic variability among economically important plant material. A thorough investigation of the existing variability will prove of major importance for both management and economic production of olive trees.  相似文献   
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