Effect of dexamethasone treatment on the immune response of Gulf Coast Native lambs to Haemonchus contortus infection     

Peña MT  Miller JE  Horohov DW 《Veterinary parasitology》2004,119(2-3):223-235

Neonatal and weaner Gulf Coast Native (Native) lambs were studied to determine whether an immunological basis underlies their natural resistance to Haemonchus contortus infection. Neonatal Native lambs (n = 8) and weaner Native lambs (n = 15) were randomly assigned to a treatment or a control group. Lambs in the treatment group received dexamethasone by intramuscular injection three times a week for 10 weeks (neonatal) and 15 weeks (weaners). All lambs were monitored for fecal egg count (FEC), blood packed cell volume (PCV), and white blood cell differential counts on a weekly basis for the duration of the studies. Neonatal lambs were kept on pasture with their dams and weaner lambs were dewormed at weaning and kept in pens where they received trickle infections. Serum antibody titers to H. contortus whole worm antigen (WWA) were determined using ELISA. Lymphocyte proliferation assays on peripheral blood mononuclear cells (PBMC) were done to assess lymphocyte function. All lambs were vaccinated with killed Brucella abortus strain 19 to assess the effect of dexamethasone treatment on antibody response. All lambs were necropsied at the end of each study to recover the contents of the gastrointestinal tract for nematode enumeration and identification. The results showed that mean FEC and mean PCV of the treatment group was significantly higher and lower, respectively, than in the control group in both neonatal and weaner lambs from weeks 6 and 5, respectively. At necropsy, total nematode count was significantly higher in treatment groups than in the control groups. Serum antibody titers to H. contortus WWA were significantly lower in treated groups than in control groups. Treatment groups showed a consistent depression in lymphocyte percentage being significantly lower from week 6 in both neonatal and weaner lambs. No differences were found in the response of PBMC to mitogen stimulation between the groups. Lambs in the control groups showed strong positive brucellosis card tests and the treatment groups did not. Dexamethasone treatment resulted in depression of the immune response and loss of natural resistance of Native lambs to H. contortus infection. The results of these studies suggest that some aspects of the immune response may underlie the natural resistance of Native sheep to H. contortus infection.  相似文献   

Chemopreventive activity of polyphenolics from black Jamapa bean (Phaseolus vulgaris L.) on HeLa and HaCaT cells     

Aparicio-Fernández X  García-Gasca T  Yousef GG  Lila MA  González de Mejia E  Loarca-Pina G 《Journal of agricultural and food chemistry》2006,54(6):2116-2122

The antiproliferative effects of 100% methanol crude extract and of Toyopearl and silica gel fractions from the seed coats of black Jamapa beans (Phaseolus vulgaris L.) were evaluated using HeLa, human adenocarcinoma cells, and HaCaT, human premalignant keratinocytes. The 100% methanol crude extract [172.2 microM equiv of (+)-catechin] increased adhesion of HeLa cells; however, 3- and 5-fold higher concentrations decreased the number of cells attached as a function of the treatment time. The highest concentration tested diminished the cell adhesion until 40% (after 24 h) to almost 80% (after 72 h). The IC50 values showed that the 100% methanol crude extract was the most effective inhibitor of HeLa cell proliferation, even when it was dissolved in dimethylsulfoxide (DMSO) [34.5 microM equiv of (+)-catechin] or in medium [97.7 microM equiv of (+)-catechin]. The Toyopearl 5 (TP5) fraction and silica gel 2 (SG2) fraction inhibited 60% of the HeLa cell proliferation. The IC50 was 154 microM equiv of (+)-catechin of the 100% methanol crude extract on HaCaT cells. Toyopearl fractions TP4 and TP6 significantly inhibited HaCaT cell proliferation, but the silica gel fractions did not have a significant effect. The 100% methanol crude extract (35 microg of dry material/mL) decreased the number of HeLa cells in the G0/G1 phase from 68.9% (for control cells) to 51.4% (for treated cells) and increased apoptosis (2.9 and 21.2% for control and treated cells, respectively). The results indicated that black Jamapa beans could be a source of polyphenolic compounds, which have an inhibitory effect toward HeLa cancer cells but are less aggressive on HaCaT premalignant cells.  相似文献   

Toll-like receptor triggering of a vitamin D-mediated human antimicrobial response     

Liu PT  Stenger S  Li H  Wenzel L  Tan BH  Krutzik SR  Ochoa MT  Schauber J  Wu K  Meinken C  Kamen DL  Wagner M  Bals R  Steinmeyer A  Zügel U  Gallo RL  Eisenberg D  Hewison M  Hollis BW  Adams JS  Bloom BR  Modlin RL 《Science (New York, N.Y.)》2006,311(5768):1770-1773

In innate immune responses, activation of Toll-like receptors (TLRs) triggers direct antimicrobial activity against intracellular bacteria, which in murine, but not human, monocytes and macrophages is mediated principally by nitric oxide. We report here that TLR activation of human macrophages up-regulated expression of the vitamin D receptor and the vitamin D-1-hydroxylase genes, leading to induction of the antimicrobial peptide cathelicidin and killing of intracellular Mycobacterium tuberculosis. We also observed that sera from African-American individuals, known to have increased susceptibility to tuberculosis, had low 25-hydroxyvitamin D and were inefficient in supporting cathelicidin messenger RNA induction. These data support a link between TLRs and vitamin D-mediated innate immunity and suggest that differences in ability of human populations to produce vitamin D may contribute to susceptibility to microbial infection.  相似文献   

Changes in the free amino acid contents of honeys during storage at ambient temperature     

Iglesias MT  Martín-Alvarez PJ  Polo MC  de Lorenzo C  Gonzalez M  Pueyo E 《Journal of agricultural and food chemistry》2006,54(24):9099-9104

This study was carried out to establish the changes in the free amino acid contents of floral honeys, honeydew honeys, and blend honeys during storage at room temperature and to test the capacity of the amino acids to distinguish the origin of the honeys after storage. For this purpose, 54 artisanal honeys (39 floral, 5 honeydew, and 10 blend) were studied. Samples were taken from recently collected honeys and at 3, 6, 9, 12, 16, 20, and 24 months after harvesting. The contents of most of the free amino acids were found to decrease with storage time, with the greatest reduction observed in the first 9 months. The contents of the amino acids aspartic acid, beta-alanine, and proline increased in the first few months after storage, reaching maximum values at 6 months, suggesting the possible existence of enzymatic activities. The application of stepwise discriminant analysis to the free amino acid content data demonstrated that the contents of the amino acids valine, beta-alanine, gamma-aminobutyric acid, serine, isoleucine, alpha-alanine, ornithine, and glutamine correctly assigned 87% of honeys to their group of origin: floral, honeydew, or blend.  相似文献   

Tuberculosis in mandrills at the Lisbon zoo     

Amado A  Albuquerque T  Gonçalves A  Duarte E  Botelho A  Fernandes T  Bernardino R  Lapão N 《The Veterinary record》2006,159(19):643

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Veterinary medical education for modern food systems: past, present, and brainstorming a future     

Morishita TY  Kahrs RF  Prasse KW  Maccabe A  Dierks R 《Journal of veterinary medical education》2006,33(4):530-532

Concepts presented here were derived from breakout sessions constituted by the 90 attendees of the Veterinary Medical Education for Modern Food Systems symposium, held in Kansas City, Missouri, USA, in October 2005. The attendees were food-animal educators, veterinary faculty, college deans and administrators, and veterinarians employed in government, industry, and private practice. Discussions at these breakout sessions focused on four primary areas: (1) determining the data needed to document the current demand for food-supply veterinarians (FSVs); (2) defining the information/skills/abilities needed within veterinary school curricula to address the current demands on FSVs; (3) outlining pre-DVM educational requirements needed to support FSVs; and (4) considering the role of post-DVM programs in meeting the demand for FSVs.  相似文献   

Silk genes support the single origin of orb webs     

Garb JE  Dimauro T  Vo V  Hayashi CY 《Science (New York, N.Y.)》2006,312(5781):1762

The orb web is a spectacular evolutionary innovation that enables spiders to catch flying prey. This elegant, geometric structure is woven with silk fibers that are renowned for their superior mechanical properties. We used silk gland expression libraries to address a long-standing controversy concerning the evolution of the orb-web architecture. Contrary to the view that the orb-web design evolved multiple times, we found that the distribution and phylogeny of silk proteins support a single, ancient origin of the orb web at least 136 million years ago. Furthermore, we substantially expanded the repository of silk sequences that can be used for the synthesis of high-performance biomaterials.  相似文献   

Early Cretaceous spider web with its prey     

Peñalver E  Grimaldi DA  Delclòs X 《Science (New York, N.Y.)》2006,312(5781):1761

The orb web is a spectacular evolutionary innovation that enables spiders to catch flying prey. This elegant, geometric structure is woven with silk fibers that are renowned for their superior mechanical properties. We used silk gland expression libraries to address a long-standing controversy concerning the evolution of the orb-web architecture. Contrary to the view that the orb-web design evolved multiple times, we found that the distribution and phylogeny of silk proteins support a single, ancient origin of the orb web at least 136 million years ago. Furthermore, we substantially expanded the repository of silk sequences that can be used for the synthesis of high-performance biomaterials.  相似文献   

Transient expression of pepper Bs2 gene in Citrus limon as an approach to evaluate its utility for management of citrus canker disease     

L. N. Sendín  M. P. Filippone  I. G. Orce  L. Rigano  R. Enrique  L. Peña  A. A. Vojnov  M. R. Marano  A. P. Castagnaro 《Plant pathology》2012,61(4):648-657

The pepper Bs2 gene confers resistance to Xanthomonas campestris pv. vesicatoria (Xcv) pathogenic strains containing the avrBs2 avirulence gene in susceptible pepper and tomato. The avrBs2 gene is highly conserved in the Xanthomonas genus and when bacteria lack this gene their growth in a susceptible host is diminished, indicating that the avrBs2 gene product could confer an adaptive advantage to the pathogen. The avrBs2 of Xanthomonas citri subsp. citri (Xcc), cause of citrus canker, shares 96% homology with avrBs2 of Xcv. To evaluate if Bs2 could recognize avrBs2 of Xcc in citrus plants and thereby activate plant defence mechanisms to increase resistance to canker, transient expression experiments were conducted using Agrobacterium tumefaciens in lemon plants subsequently challenged with wildtype Xcc. The results showed that transient expression of Bs2 reduced canker formation in lemon and induced plant defence mechanisms, as shown by callose deposition and PR‐1 expression. Moreover, when an avrBs2 mutant of Xcc was used, no decrease in disease symptoms was observed. This work shows that the Bs2 gene from Solanaceae is functional in lemon, a member of the Rutaceae family. Therefore, Bs2 is a potential candidate gene for stable expression in transgenic citrus plants in order to improve resistance to canker disease.  相似文献   

Conventional and real-time PCR for the identification of Fusarium fujikuroi and Fusarium proliferatum from diseased rice tissues and seeds     

Maria Teresa Amatulli  Davide Spadaro  Maria Lodovica Gullino  Angelo Garibaldi 《European journal of plant pathology / European Foundation for Plant Pathology》2012,134(2):401-408

Fusarium fujikuroi is a species of the Gibberella fujikuroi species complex (GFSC) and the causal agent of bakanae disease on rice. Even if F. fujikuroi is the most abundant Fusarium species found on rice, other species can also be isolated from rice, such as F. proliferatum. Multiple alignment of translation elongation factor (TEF) gene sequences of different Fusarium spp., showed a deletion of six nucleotides in F. fujikuroi sequence and a two nucleotide polymorphism in the same region of F. proliferatum sequence. These elements of variability were used to develop a conventional and Real-Time PCR assay for diagnosis. The species specific primer pairs (Fuji1F/TEF1R and Proli1F/TEF1R) gave a product of 179 and 188?bp for F. fujikuroi and F. proliferatum respectively. Primer specificity was confirmed by analyzing the DNA of the most representative species of the GFSC and 298 strains of Fusarium spp. isolated from rice plants and seeds in Italy. The specific primers were also successfully used to detect fungal presence directly from infected rice tissues and seeds, providing a rapid tool for the early detection of pathogen contamination.  相似文献