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Strain Combinations (strain + combination)
Selected AbstractsAKT1 leader gene and downstream targets are involved in a rat model of kidney allograft tolerance,JOURNAL OF CELLULAR BIOCHEMISTRY, Issue 3 2010Vojislav Jovanovic Abstract Tolerance is the so-called "Holy Grail" of transplantation but achieving this state is proving a major challenge, particularly in the clinical settings. This tolerance state can be induced in rodent models using a variety of maneuvers. This phenomenon is classically characterized by donor specificity (recipients accept a secondary donor-specific allograft but reject third-party allograft) as well as by the absence of chronic rejection lesion. We previously showed that administration and anti-donor anti-class II serum on the day of transplantation induce tolerance to a kidney allograft in the LEW-1W to LEW-1A strain combination. In this study, we used DNA microarrays to compare gene patterns involved in anti-donor anti-class II tolerated or untreated syngeneic kidney transplants in this strain combination. Statistical and non-statistical analyses were combined with ab initio analysis, using the recently developed leader gene approach, to shed new light on this phenomenon. Theoretical and experimental results suggest that tolerance and rejection outcome may be in large part determined by low expression variations of some genes, which can form a core gene network around specific genes such as Rac1, NFKB1, RelA, AKT1, IKBKB, BCL2, BCLX, and CHUK. Through this model, we showed that AKT1 gene, WNT pathway and NO synthesis are strictly connected to each other and may play an important role in kidney tolerance and rejection processes, with AKT1 gene being the center of this complex network of interactions. J. Cell. Biochem. 111: 709,719, 2010. © 2010 Wiley-Liss, Inc. [source] Rhizobacteria-mediated resistance against the blackeye cowpea mosaic strain of bean common mosaic virus in cowpea (Vigna unguiculata)PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 10 2009Arakere Chunchegowda Udaya Shankar Abstract BACKGROUND: The present study investigated the effect of seven Bacillus -species plant-growth-promoting rhizobacteria (PGPR) seed treatments on the induction of disease resistance in cowpea against mosaic disease caused by the blackeye cowpea mosaic strain of bean common mosaic virus (BCMV). RESULTS: Initially, although all PGPR strains recorded significant enhancement of seed germination and seedling vigour, GBO3 and T4 strains were very promising. In general, all strains gave reduced BCMV incidence compared with the non-bacterised control, both under screen-house and under field conditions. Cowpea seeds treated with Bacillus pumilus (T4) and Bacillus subtilis (GBO3) strains offered protection of 42 and 41% against BCMV under screen-house conditions. Under field conditions, strain GBO3 offered 34% protection against BCMV. The protection offered by PGPR strains against BCMV was evaluated by indirect enzyme-linked immunosorbent assay (ELISA), with lowest immunoreactive values recorded in cowpea seeds treated with strains GBO3 and T4 in comparison with the non-bacterised control. In addition, it was observed that strain combination worked better in inducing resistance than individual strains. Cowpea seeds treated with a combination of strains GBO3 + T4 registered the highest protection against BCMV. CONCLUSION: PGPR strains were effective in protecting cowpea plants against BCMV under both screen-house and field conditions by inducing resistance against the virus. Thus, it is proposed that PGPR strains, particularly GBO3, could be potential inducers against BCMV and growth enhancers in cowpea. Copyright © 2009 Society of Chemical Industry [source] CD8+ T-Cell Depletion and Rapamycin Synergize with Combined Coreceptor/Stimulation Blockade to Induce Robust Limb Allograft Tolerance in MiceAMERICAN JOURNAL OF TRANSPLANTATION, Issue 12 2008Z. Li The growing development of composite tissue allografts (CTA) highlights the need for tolerance induction protocols. Herein, we developed a mouse model of heterotopic limb allograft in a stringent strain combination in which potentially tolerogenic strategies were tested taking advantage of donor stem cells in the grafted limb. BALB/c allografts were transplanted into C57BL/6 mice treated with anti-CD154 mAb, nondepleting anti-CD4 combined to either depleting or nondepleting anti-CD8 mAbs. Some groups received additional rapamycin. Both depleting and nondepleting mAb combinations without rapamycin only delayed limb allograft rejection, whereas the addition of rapamycin induced long-term allograft survival in both combinations. Nevertheless, robust donor-specific tolerance, defined by the acceptance of a fresh donor-type skin allograft and simultaneous rejection of third-party grafts, required initial CD8+ T-cell depletion. Mixed donor-recipient chimerism was observed in lymphoid organs and recipient bone marrow of tolerant but not rejecting animals. Tolerance specificity was confirmed by the inability to produce IL-2, IFN-, and TNF-, in MLC with donor antigen while significant alloreactivity persisted against third- party alloantigens. Collectively, these results show that robust CTA tolerance and mixed donor-recipient chimerism can be achieved in response to the synergizing combination of rapamycin, transient CD8+ T-cell depletion and costimulation/coreceptor blockade. [source] INTERGENOMIC EPISTASIS AND COEVOLUTIONARY CONSTRAINT IN PLANTS AND RHIZOBIAEVOLUTION, Issue 5 2010Katy D. Heath Studying how the fitness benefits of mutualism differ among a wide range of partner genotypes, and at multiple spatial scales, can shed light on the processes that maintain mutualism and structure coevolutionary interactions. Using legumes and rhizobia from three natural populations, I studied the symbiotic fitness benefits for both partners in 108 plant maternal family by rhizobium strain combinations. Genotype-by-genotype (G × G) interactions among local genotypes and among partner populations determined, in part, the benefits of mutualism for both partners; for example, the fitness effects of particular rhizobium strains ranged from uncooperative to mutualistic depending on the plant family. Correlations between plant and rhizobium fitness benefits suggest a trade off, and therefore a potential conflict, between the interests of the two partners. These results suggest that legume,rhizobium mutualisms are dynamic at multiple spatial scales, and that strictly additive models of mutualism benefits may ignore dynamics potentially important to both the maintenance of genetic variation and the generation of geographic patterns in coevolutionary interactions. [source] Modified technique of ureteroureterostomy in rat kidney transplantationMICROSURGERY, Issue 4 2004Alexander Pietsch Dr. Med. Different strain combinations of rats are available to study immunological and transplant-related problems in the models of kidney transplantation. Although numerous modifications of surgical techniques for ureteric reconstruction are evaluated in order to reduce complications and to extend long-term survival, ureteric complications still occur frequently, especially when the difference in diameter of both donor and host ureters is disproportionate. Instead of using the current nonsplinted ureteroureterostomy (method A), a versatile and rapid technical modification (method B) was developed to perform reconstruction of ureters with disproportionate diameters. The overall incidence of ureteric complications was 80% (8/10) using method A, whereas this rate was significantly reduced to 15% (3/20) using method B (P < 0.001). Our modification proves the feasibility of nonsplinted ureteroureterostomy in a technical, highly demanding rat model of kidney transplantation with an acceptable rate of ureteric complication, considering the disproportionate difference in diameter between the host and donor ureters. © 2004 Wiley-Liss, Inc. [source] Survival of ovarian allografts in an experimental animal modelPEDIATRIC TRANSPLANTATION, Issue 6 2007Roger G. Gosden Abstract: Transplantation of ovarian tissue is a promising strategy for fertility preservation in young cancer patients with premature ovarian failure if they have cryopreserved their own tissue before undergoing gonadotoxic treatment. However, extension of ovary donation to children and adults seeking treatment for hypogonadism is controversial unless the tissue does not provoke an immune reaction or specific tolerance can be safely and effectively achieved. The survival of heterotopic ovarian allografts was tested in a mouse model. Isografts were placed under the kidney capsule of ovariectomized animals differing at the H-2 haplotype (H-2d or H-2k). Within three wk, and in contrast to isografts, the allografts were rejected, although their survival was extended when donor and host strains shared the same haplotype (H-2k). Allograft survival was not improved if the tissue was implanted orthotopically. When monoclonal antibodies to CD4 antigens were administered at doses exceeding those effective for long-term tolerance to cardiac allografts, graft survival was prolonged in one of two strain combinations, but they failed to restore fertility. These results indicate that the ovary is not an immunologically privileged organ, as the older literature suggested, and chronic immunosuppression is likely to be required for ovarian allografts in clinical settings. [source] Portal Venous Donor-Specific Transfusion in Conjunction with Sirolimus Prolongs Renal Allograft Survival in Nonhuman PrimatesAMERICAN JOURNAL OF TRANSPLANTATION, Issue 1 2009K. K. Dhanireddy Pretransplant exposure to donor antigen is known to modulate recipient alloimmunity, and frequently results in sensitization. However, donor-specific transfusion (DST) can have a protolerant effect that is dependent on route, dose and coadministered immunosuppression. Rodent studies have shown in some strain combinations that portal venous (PV) DST alone can induce tolerance, and uncontrolled clinical use of PVDST has been reported. In order to determine if pretransplant PVDST has a clinically relevant salutary effect, we studied it and the influence of concomitant immunosuppression in rhesus monkeys undergoing renal allotransplantation. Animals received PVDST with unfractionated bone marrow and/or tacrolimus or sirolimus 1 week prior to transplantation. Graft survival was assessed without any posttransplant immunosuppression. PVDST alone or in combination with tacrolimus was ineffective. However, PVDST in combination with sirolimus significantly prolonged renal allograft survival to a mean of 24 days. Preoperative sirolimus alone had no effect, and peripheral DST with sirolimus prolonged graft survival in 2/4 animals, but resulted in accelerated rejection in 2/4 animals. These data demonstrate that PVDST in combination with sirolimus delays rejection in a modest but measurable way in a rigorous model. It may thus be a preferable method for donor antigen administration. [source] Increased expression of epidermal fatty acid-binding protein by alveolar macrophages during acute rejection of rat lungsAPMIS, Issue 10 2010JULIA HOLLER Holler J, Zakrzewicz A, Garn H, Hirschburger M, Kummer W, Padberg W, Grau V. Increased expression of epidermal fatty acid-binding protein by alveolar macrophages during acute rejection of rat lungs. APMIS 2010; 118: 791,800. In the lung, epidermal fatty acid-binding protein (E-FABP) is expressed by alveolar macrophages (AM) and alveolar epithelial cells type II (AEII). E-FABP may regulate macrophage activation and is involved in the metabolism of surfactant phospholipids. As macrophage activation and surfactant dysfunction are associated with rejection, we hypothesize that E-FABP expression is changed during acute rejection of pulmonary grafts. Orthotopic left lung transplantations were performed in the Dark Agouti to Lewis and in the isogeneic Lewis to Lewis rat strain combinations. E-FABP expression was analyzed in the lung by immunohistochemistry, immunoblotting and quantitative reverse transcription-polymerase chain reaction (RT-PCR). Alveolar leukocytes obtained by bronchoalveolar lavage were analyzed by RT-PCR. Immunohistochemistry of isografts revealed strong E-FABP immunoreactivity in AEII and a moderate immunoreactivity in AM. In allografts undergoing acute rejection, AM exhibiting increased E-FABP immunoreactivity accumulated. Immunoblots revealed a single band at 15 kDa, which corresponds to the expected molecular mass of E-FABP. The levels of E-FABP mRNA were higher in allografts than in isografts and control lungs. Furthermore, alveolar leukocytes isolated by bronchoalveolar lavage from allografts displayed higher E-FABP mRNA expression levels than leukocytes from isografts and controls. In conclusion, we demonstrate for the first time upregulation of E-FABP expression in AM during severe inflammation. [source] DNA markers for estimation of inbreeding depression and heterosis in the guppy Poecilia reticulataAQUACULTURE RESEARCH, Issue 11 2003Takahito Shikano Abstract Molecular markers have significant potential for use in precise breeding programmes in aquaculture. This paper reviews the use of DNA markers to estimate inbreeding depression and heterosis in the guppy Poecilia reticulata. Full-sib matings revealed that inbreeding causes declines in survival and salinity tolerance, but not in undwarfism, growth and high water temperature tolerance, indicating the effects of inbreeding differ among fitness-related traits. Salinity tolerance was used to quantify the level of inbreeding depression and heterosis because the trait is strongly sensitive to inbreeding and shows a linear decrease with an increase in inbreeding coefficient. A positive correlation was observed between heterozygosity at microsatellite loci and salinity tolerance among 17 guppy populations. This indicates that heterozygosity estimated from microsatellites is a useful indicator for the estimation of inbreeding depression, suggesting that overall heterozygosity is important for fitness-related traits that show inbreeding depression. Use of DNA markers to estimate the amount of heterosis in various strain combinations was examined using diallele and reciprocal crosses among four domestic strains. The amount of heterosis differed among the strain combinations and correlated with Nei's genetic distance measured by microsatellites and also by dissimilarity using random amplified polymorphic DNA (RAPD) analysis. This indicates that microsatellite and RAPD markers are useful for estimating the amount of heterosis in various strain combinations, further suggesting that the amount of heterosis depends on the genetic differences between the strains. The present study showed that DNA markers are useful tools for estimating inbreeding depression and heterosis in guppy breeding. [source] A comparative genetic analysis between collagen-induced arthritis and pristane-induced arthritisARTHRITIS & RHEUMATISM, Issue 8 2003Peter Olofsson Objective To compare the genetic regulation of collagen-induced arthritis (CIA) with that of pristane-induced arthritis (PIA) in rats. Methods A genome-wide linkage analysis of an (E3 × DA)DA backcross of rats with CIA (n = 364 male rats; the same strain combinations as previously used to determine the genetic control of PIA) was performed. The strongest loci in both CIA and PIA (i.e., Cia12/Pia4 and Cia13/Pia7) were isolated in congenic strains. Susceptibility in both congenic strains was tested in rats with CIA and in rats with PIA. Results We found a striking, although not complete, similarity of the arthritis-controlling loci in CIA and in PIA, as well as the previously defined loci associated with cartilage destruction, antibody production, and the acute-phase response. All major PIA quantitative trait loci (QTLs) identified in early severe arthritis were also strong regulators of CIA. The 2 strongest QTLs, Cia12/Pia4 on chromosome 12 and Cia13/Pia7 on chromosome 4, were also analyzed in congenic strains with DA or E3 as the background genome. Consistent with the results of linkage analysis, the congenic strain experiments showed that the chromosome 4 locus was more penetrant in CIA than in PIA, while the chromosome 12 locus almost completely dominated the control of PIA severity. Conclusion The underlying genetic control of CIA was found to have many, but not all, pathogenic mechanisms in common with PIA, despite the use of a cartilage-specific antigen (type II collagen) to induce CIA but not PIA. [source] Effect of Inoculum Composition and Low KCl Supplementation on the Biological and Rheological Stability of an Immobilized-Cell System for Mixed Mesophilic Lactic Starter ProductionBIOTECHNOLOGY PROGRESS, Issue 6 2001L. Lamboley Two strains of Lactococcus lactissubsp. lactis (L. lactis KB and KBP) and one of L. lactissubsp. lactis biovar. diacetylactis (L. diacetylactis MD) were immobilized separately in ,-carrageenan-locust bean gum gel beads. Continuous fermentations were carried out in supplemented whey permeate in a 1-L pH-controlled stirred tank reactor inoculated with a 30% (v/v) bead inoculum and a bead ratio of 55:30:15 for KB, KBP, and MD, respectively. The process demonstrated a high productivity and microbial stability during the 7-week continuous culture. Compared with previous experiments carried out with an inoculum bead ratio of 33:33:33 for KB, KBP, and MD beads, respectively, the modification of the inoculum bead ratio had apparently little effect on free and immobilized, total and specific populations. A dominant behavior of L. diacetylactis MD over the other strains of the mixed culture was observed both with free-cell populations in the effluent and with immobilized-cell populations. Additional experiments were carried out with other strain combinations for continuous inoculation-prefermentation of milk. The data also confirmed the dominance of L. diacetylactis during long-term continuous immobilized-cell fermentations. This dominance may be tentatively explained by the local competition involved in the development of the bead cross-contamination and in citrate utilization by L. diacetylactis strains. The gel beads demonstrated a high rheological stability during the 7-week continuous fermentation even at low KCl supplementation of the broth medium (25 mM KCl). [source] | |||||||||||||