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1.
Lycopersicon esculentum cultivar Micro-Tom is a miniature tomato with many advantages for studies of the molecular biology and physiology of plants. To evaluate the suitability of Micro-Tom as a host plant for the study of pathogenesis, Micro-Tom plants were inoculated with 16 well-known fungal, bacterial, and viral pathogens of tomato. Athelia rolfsii, Botryotinia fuckeliana, Oidium sp., Phytophthora infestans, and Sclerotinia sclerotiorum caused typical symptoms and sporulated abundantly on Micro-Tom. Micro-Tom was resistant to Alternaria alternata, Corynespora cassiicola, and Fusarium oxysporum. When Micro-Tom was inoculated with 17 isolates of Ralstonia solanacearum, many isolates induced wilt symptoms. Agrobacterium tumefaciens also was pathogenic, causing crown galls on stem tissue after needle prick inoculation. In Micro-Tom sprayed with Pseudomonas syringae pv. tomato, P. s. pv. tabaci, or P. s. pv. glycinea, bacterial populations did not increase, and yellow lesions appeared only on leaves sprayed with P. s. pv. tomato. Tomato mosaic virus, Tomato aspermy virus, and Cucumber mosaic virus systemically infected Micro-Tom, which developed symptoms characteristic of other cultivars of tomato after infection with the respective virus. These results indicated that Micro-Tom was generally susceptible to most of the important tomato pathogens and developed typical symptoms, whereas certain pathogens were restricted by either hypersensitive resistance or nonhost resistance on Micro-Tom. Therefore, an assortment of Micro-Tom–pathogen systems should provide excellent models for studying the mechanism of susceptible and resistant interactions between plants and pathogens.  相似文献   
2.

Potassium has important physiological functions in eucalypt plantations, increasing their productivity when applied to soil via mineral fertilizers. There is interest in identifying alternative sources to KCl owing to its high cost and limited reserves. The aim of the study was to test the effect of replacing KCl with NaCl and phonolite rock powder. Two comparisons were made: (1) application of 283 kg ha?1 of KCl compared with that of 2125 kg ha?1 of phonolite rock powder (equivalent to 170 kg ha?1 of K2O in both treatments); (2) application of 139 kg ha?1 of NaCl compared with that of 183 kg ha?1 of KCl (equivalent to 2.33 kmol Na and K, respectively). Radial growth, soil water content, leaf water potential (Ψ), accumulated transpiration, stem volume and biomass increment, as well as water use efficiency (WUE) were evaluated. In the first comparison, both fertilizations presented equal values for all characteristics evaluated. In the second, the accumulated transpiration in trees fertilized with KCl was 17% higher than that in plants fertilized with NaCl. In contrast, the WUE was 20% higher in the trees fertilized with NaCl than in those fertilized with KCl, reflecting the lower water consumption for the same increment in stem volume and biomass. We conclude that phonolite rock powder and NaCl are possible substitutes for conventional K fertilization performed with KCl.

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3.
Semen collection has an essential role in the initial bacterial load in boar ejaculates and extended semen. The study aimed to explore the efficacy of an adjusted penis fixation in a semi-automatic collection system on reducing bacterial contamination of ejaculates in two-boar studs with different scenarios. Historically, stud A had low levels of bacterial load in raw semen, while stud B had a high level of contamination. A total of 56 mature boars had their semen collected using two methods of penis fixation: (a) Traditional: The penis was fixed directly with the artificial cervix and transferred to the adjustable clamp; (b) Adjusted: The fixation was performed with one gloved-hand, and after exteriorization, the penis was gripped using the artificial cervix with the other gloved-hand and transferred to the adjustable clamp. The bacterial load (p = .0045) and the occurrence of ejaculates >231 CFU/ml (p = .0101) were reduced in the Adjusted compared to the Traditional method. Bacterial load was reduced when using the Adjusted method in stud B (p = .0011), which showed a greater occurrence of critical factors for bacterial contamination (p ≤ .0034). The Adjusted method reduced the occurrence of ejaculates >231 CFU/ml when the preputial ostium was dirty (p = .016) and the duration of semen collection was >7 min (p = .022) compared to the Traditional method. In conclusion, the Adjusted penis fixation was efficient in reducing bacterial load of ejaculates, mainly in boar stud B, which had high contamination challenges.  相似文献   
4.
A TaqMan-based real-time PCR assay was developed for the diagnosis of Anaplasma marginale infection of cattle. The established assay was proven to be highly specific, since no cross-reactions were observed with other Anaplasma species of ruminants, including the closely related Anaplasma centrale, or other haemoparasites of ruminants (Anaplasma bovis, Anaplasma ovis, Anaplasma phagocytophilum, Babesia bovis, Babesia bigemina, Theileria annulata and Theileria buffeli). The detection limit was equal to that of nested (n)PCR (10(1) copies of standard DNA and 3 x 10(1) infected erythrocytes ml(-1) of blood). The assay was also reproducible, as shown by satisfactory low intra-assay and inter-assay coefficients of variation. Fifty-four blood samples of ruminants (cattle, n = 51; sheep, n = 2; goats, n = 1), that had been tested previously by reverse line blot (RLB) hybridisation, were subjected to an nPCR assay and the newly established real-time PCR assay. By using real-time PCR, A. marginale DNA was detected in 39/51 bovine samples, with DNA titres ranging from 3.60 x 10(3) to 5.70 x 10(8) copies ml(-1) of blood, whereas sheep and goat samples tested negative. The concordance with nPCR was 100%, whereas a unique sample that had tested negative by RLB gave positive results by nPCR and real-time PCR. The established assay could overcome the limitations of existing diagnostic methods, allowing for simultaneous detection and quantification of the A. marginale DNA in bovine blood, that is essential to support the clinical diagnosis, to assess the carrier status of the animals and to evaluate the efficacy of vaccines and antirickettsial drugs.  相似文献   
5.
Besides infection in humans, Salmonella enteritidis can also cause serious illness in young chickens. However, the genetic and immunological parameters important for the disease in chickens are not well characterized. In this study, processes in the chicken intestine in response to a Salmonella infection were investigated in two different chicken lines. One-day-old chickens were orally infected with Salmonella. T-cell subpopulations, phagocytic properties of intestinal mononuclear cells and RNA expression levels of the jejunum were investigated. The two chicken lines differed in the amount of cfu in the liver and growth retardation after the infection. Differences in phagocytic activity of intestinal mononuclear cells were found between control and Salmonella infected chickens. The number of CD4+ T-cells of the intestine decreased after the Salmonella infection in one chicken line, while the number of CD8+ T-cells increased in both chicken lines, but the time post infection of this increase differed between the lines. In one chicken line the expression levels of the genes carboxypeptidase M and similar to ORF2 decreased after the Salmonella infection, which might be related to a decrease in the amount of macrophages. With the microarray, ten genes were found that were regulated in only one of the chicken lines, while we found six genes regulated in response to the infection in both chicken lines. So differences in genetic background of the chickens influence the intestinal host response of the Salmonella infection as observed by phagocytic activity, gene expression and changes in the number of T-cell subpopulations and macrophages.  相似文献   
6.
A 2-year-old Labrador Retriever developed atrophy of the right temporal muscle, subsequently showed generalized seizure and died 2 months after the clinical onset. Postmortem examination revealed the tumor masses in the right mandibulopharyngeal area, nasopharynx and intracranial space. Histopathologically, these tumor masses were composed of small round neoplastic cells and neuropil-like stroma separated by fibrovascular septa. In the neoplastic masses, small neoplastic cells with round to oval hyperchromatic nuclei and scanty cytoplasm predominated, and angulated neoplastic cells with larger nuclei and moderate cytoplasm were scattered. Immunohistochemically, neoplastic cells were positive for neuron specific enorase, neurofilament protein, chromogranin A, synaptophysin and tyrosine hydroxylase. Based on these findings, this case was diagnosed as peripheral neuroblastoma, presumably originated from the sympathetic ganglion, maybe right craninal cervical ganglion.  相似文献   
7.
Canine necrotizing meningoencephalitis (NME) and granulomatous meningoencephalomyelitis (GME) were compared pathologically. Gross observation exhibited lateral ventricular dilation and discoloration, malacia and/or cavitation of the cerebrum in NME. On the contrary, gross changes were milder in GME, except for occasional visible granulomatous mass formation. Histopathologically, the lesions of NME were distributed predominantly in the cerebral cortex and various degrees of inflammatory and necrotic changes were observed according to clinical stages. Besides, microscopic lesions of GME were mainly distributed in the white matter of the cerebrum, cerebellum and brainstem, which are characterized by perivascular cuffing, multiple granulomas and leptomeningeal infiltrates. Although macrophages and lymphocytes were predominant in the inflammatory lesions of both disorders, macrophages in GME transformed into epithelioid cells and exhibited more massive infiltration. Although lectin RCA-1-reactive cells were numerous in both disorders, lysozyme immunoreactive cells in NME were fewer than that in GME. Parenchymal infiltration of MAC387-positive cells was common in GME and limited in NME. The number of CD3-positive lymphocytes in the GME lesions tended to be greater than in NME, though the difference was not statistically significant. Morphological and immunohistochemical differences of the lesions, in particular, the characteristics of infiltrative macrophages may reflect these different pathogeneses of the two disorders.  相似文献   
8.
We reported that meat chicks have either a greater capability to acclimatize to novel environments, or a blunted hypothalamic‐pituitary‐adrenal response to novel environments compared with layer chicks in a commercial base. The present study compared the differences in behavior and plasma corticosterone concentrations under isolation‐induced stress between neonatal meat and layer Nagoya chicks which had been separated from the same population. Both types of neonatal chicks reared in groups were individually separated and their spontaneous activity and distress‐induced vocalizations were monitored for 10 min. The responses of the two types were remarkably different, with the meat chicks being less active than the layer chicks. Distress‐induced vocalizations were fewer in the meat than in the layer chicks. The meat chicks spent more time in a sleeping posture during isolation‐induced stress. Plasma corticosterone concentrations measured at the end of the test tended to be higher in the layer chicks than in meat ones, but not significantly. In conclusion, the selection of Nagoya chickens for meat and layer may have trends similar to those observed in commercial chickens in relation to stress susceptibility.  相似文献   
9.
The timing of parturition was recorded for a total of 56 beef cattle (Japanese Black × Holstein Friesian) on different dietary treatments. The rate of calving during daylight hours in cows night‐fed (18.00 hours) with a roughage diet was significantly higher than that in cows night‐fed with a high concentrate diet (79.2% vs 38.5%, P < 0.05). Subsequently, the vaginal temperature (VT) of these cows was analyzed using a cosinor method. When the feeding schedule was changed from twice daily (08.30 and 15.30 hours) to night feeding, the periodicity, the acrophase and the bathyphase, which were the parameters of the cosine curve, were unstable from the first day of night feeding until after day 6 (P < 0.05). Prior to parturition, the midline‐estimating statistic of rhythm (MESOR) and the amplitude for the cows that were fed a high‐roughage diet at night and that calved at night‐time were lower and larger, respectively, than that for the other treatments (P < 0.01). Based on these results, the time of parturition in most of the beef cows was influenced by feeding time and diet composition. Those cows that calved at night‐time in spite of night feeding had lower vaginal temperatures.  相似文献   
10.
This study was conducted to determine the age and liveweight at puberty of 120 crossbred beef heifers submitted to four diets to achieve predetermined weight gains (kg/day): 0.5 (G500; n?=?32), 0.75 (G750; n?=?32), 1.0 (G1000; n?=?29), and 1.25 (G1250; n?=?27). Animals were classified depending on their level of crossing between Nelore (N) and Hereford (H): 25%N-75%H, 37.5%N-63.5%H, 43.7%N-56.7%H, 50%N-50%H, and 75%N-25%H. Reproductive evaluation was performed at the beginning and at the end of the experimental period by ultrasonography and hormone analysis. The average age and liveweight at puberty were 388.0?±?1.9 days and 331.4?±?1.3 kg, respectively. Animals from the 25%N-75%H group reached puberty earlier than heifers from other genetic groups supplemented with G1250 diet (P?<?0.05). Heifers with higher degree of Nelore (75%N-25%H) fed with G1000 diet showed estrus 42 days prior to mating, but only 57 % reached puberty at mating (P?<?0.05). Heifers with follicles of higher diameter reached puberty (P?<?0.05) earlier. Higher average daily weight gain showed a positive effect on follicular diameter and IGF-I level at puberty (P?<?0.01). Concentrations of GH were lower in heifers fed G1250 compared to G1000 diet (P?<?0.05). There was a significant interaction between nutritional level and insulin levels at puberty (P?<?0.01). We demonstrated the relationship between IGF-I and average daily gain on the onset of puberty in heifers. In conclusion, heifers submitted to the higher feeding level showed a higher follicular diameter and were younger at puberty.  相似文献   
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