Abstract Yersinia pestis was introduced to North America around 1900 and leads to nearly 100% mortality in prairie dog (Cynomys spp.) colonies during epizootic events, which suggests this pathogen may exert a strong selective force. We characterized genetic diversity at an MHC class II locus (DRB1) in Gunnison's prairie dog (C. gunnisoni) and quantified population genetic structure at the DRB1 versus 12 microsatellite loci in three large Arizona colonies. Two colonies, Seligman (SE) and Espee Ranch (ES), have experienced multiple plague‐related die‐offs in recent years, whereas plague has never been documented at Aubrey Valley (AV). We found fairly low allelic diversity at the DRB1 locus, with one allele (DRB1*01) at high frequency (0.67–0.87) in all colonies. Two other DRB1 alleles appear to be trans‐species polymorphisms shared with the black‐tailed prairie dog (C. ludovicianus), indicating that these alleles have been maintained across evolutionary time frames. Estimates of genetic differentiation were generally lower at the MHC locus (F ST = 0.033) than at microsatellite markers (F ST = 0.098). The reduced differentiation at DRB1 may indicate that selection has been important for shaping variation at MHC loci, regardless of the presence or absence of plague in recent decades. However, genetic drift has probably also influenced the DRB1 locus because its level of differentiation was not different from that of microsatellites in an F ST outlier analysis. We then compared specific MHC alleles to plague survivorship in 60 C. gunnisoni that had been experimentally infected with Y. pestis. We found that survival was greater in individuals that carried at least one copy of the most common allele (DRB1*01) compared to those that did not (60% vs. 20%). Although the sample sizes of these two groups were unbalanced, this result suggests the possibility that this MHC class II locus, or a nearby linked gene, could play a role in plague survival.

Das Empfinden von Schmerz soll einen Organismus vor schädlichen Umwelteinflüssen warnen, doch die Erfahrung von Schmerzen ist auch assoziiert mit einer erhöhten Sterblichkeit. Bisher ist allerdings nicht bekannt, wie das Erleben von Schmerzen und der Alterungsprozess eines Individuums zusammenhängen. Eine US-amerikanische Arbeitsgruppe hat nun den Einfluss eines Schmerzrezeptors auf Langlebigkeit und Metabolismus bei Mäusen untersucht.

The relationship among ammonia levels, cage-changing frequency, and bedding types is an important and potentially controversial topic in the laboratory animal science community. Some bedding options may not provide sufficient urine absorption and bacterial regulation to minimize ammonia production during the interval between cage changes. High intracage ammonia levels can cause subclinical degeneration and inflammation of nasal passages, rhinitis and olfactory epithelial necrosis in exposed mice. Here we sought to compare the effects of 4 commonly used bedding substrates (1/4-in. irradiated corncob, reclaimed wood pulp, aspen wood chips, and recycled newspaper) on ammonia generation when housing female C57BL/6 mice in static and individually ventilated caging. Intracage ammonia levels were measured daily for 1 wk (static cage experiment) or 2 wk (IVC experiment). The results of this study suggest that the corncob, aspen wood chip, and recycled newspaper beddings that we tested are suitable for once-weekly cage changing for static cages and for changing every 2 wk for IVC. However, ammonia levels were not controlled appropriately in cages containing reclaimed wood pulp bedding, and pathologic changes occurred within 1 wk in the nares of mice housed on this bedding in static cages.

Disuse atrophy of both muscle and bone can occur rapidly during periods of inactivity. In several rodent models developed for the study of disuse atrophy, immobilization is induced by prolonged cage restraint, hind limb unloading, tenotomy, sciatic nerve block or sciatic denervation. In less tractable species such as wild-caught hibernating rodents, the sciatic denervation model is superior in terms of both animal welfare and applicability to the characteristics of natural cases of disuse atrophy. The authors describe a refined surgical approach to sciatic denervation in golden-mantled ground squirrels (Callospermophilus lateralis), a hibernating species, that improves animal welfare and reduces the incidence of post-operative complications such as autotomy.

The sensation of pain is associated with increased mortality, but it is unknown whether pain perception can directly affect aging. We find that mice lacking TRPV1 pain receptors are long-lived, displaying a youthful metabolic profile at old age. Loss of TRPV1 inactivates a calcium-signaling cascade that ends in the nuclear exclusion of the CREB-regulated transcriptional coactivator CRTC1 within pain sensory neurons originating from the spinal cord. In long-lived TRPV1 knockout mice, CRTC1 nuclear exclusion decreases production of the neuropeptide CGRP from sensory endings innervating the pancreatic islets, subsequently promoting insulin secretion and metabolic health. In contrast, CGRP homeostasis is disrupted with age in wild-type mice, resulting in metabolic decline. We show that pharmacologic inactivation of CGRP receptors in old wild-type animals can restore metabolic health. These data suggest that ablation of select pain sensory receptors or the inhibition of CGRP are associated with increased metabolic health and control longevity.

Prairie dogs (Cynomys spp.) are highly susceptible to Yersinia pestis, with ≥99% mortality reported from multiple studies of plague epizootics. A colony of Gunnison's prairie dogs (Cynomys gunnisoni) in the Aubrey Valley (AV) of northern Arizona appears to have survived several regional epizootics of plague, whereas nearby colonies have been severely affected by Y. pestis. To examine potential mechanisms accounting for survival in the AV colony, we conducted a laboratory Y. pestis challenge experiment on 60 wild-caught prairie dogs from AV and from a nearby, large colony with frequent past outbreaks of plague, Espee (n = 30 per colony). Test animals were challenged subcutaneously with the fully virulent Y. pestis strain CO92 at three doses: 50, 5,000, and 50,000 colony-forming units (cfu); this range is lethal in black-tailed prairie dogs (Cynomys ludovicianus). Contrary to our expectations, only 40% of the animals died. Although mortality trended higher in the Espee colony (50%) compared with AV (30%), the differences among infectious doses were not statistically significant. Only 39% of the survivors developed moderate to high antibody levels to Y. pestis, indicating that mechanisms other than humoral immunity are important in resistance to plague. The ratio of neutrophils to lymphocytes was not correlated with plague survival in this study. However, several immune proteins with roles in innate immunity (VCAM-1, CXCL-1, and vWF) were upregulated during plague infection and warrant further inquiry into their role for protection against this disease. These results suggest plague resistance exists in wild populations of the Gunnison's prairie dog and provide important directions for future studies.

Over the past 40 yr, epizootics of plague (Yersinia pestis) in northern Arizona have reduced populations of the Gunnison's prairie dog (Cynomys gunnisoni), with the exception of a large population found in the Aubrey Valley (AV). To examine potential mechanisms accounting for their survival, we collected prairie dog serum samples in 2005-2006 from AV and a neighboring population near Seligman (SE), Arizona. We quantified gene expression at 58 diverse immune proteins using a multiplexed enzyme-linked immunosorbent assay panel. We found a subset of proteins important in coagulation and inflammation (tissue factor [TF], calbindin [Cal], and thrombopoietin [TPO]) and T-cell responses (CD40L and CD40) that were present in AV at levels two to eight times greater than SE. These results suggest that AV and SE animals might differ in their ability to mount an immune response.

into an embryo was a matter to be handled by the submitting investigator and the IBC, not by the IACUC or ZINC. Regardless of which investigator needs to obtain approval for use of nucleic acids, Great Eastern University’s IBC has oversight. However, the IACUC also has a responsibility to ensure that inserts do not affect the health of animals and animal workers at the institution. Lack of clarity regarding embryo housing makes it difficult to determine any potential threat to the colony, but caretakers can act as fomites if the nucleic acids have the potential to introduce pathogens, including zoonoses. Another reason why Finn’s answer is insufficient is that the type of nucleic acid used affects the number of embryos needed, which ultimately determines the number of adult breeding animals needed. In addition, any hatchlings become transgenic animals under IACUC responsibility. Therefore, the justification for animal numbers will need to include at least a proposed list of groups, if not specific substances, to be injected. This could be handled as a blanket protocol if Finn states that he will amend it for each specific substance before its use.

RATIONALE: To investigate the role of cysteinyl leukotrienes in altered bone marrow eosinophil and T cell numbers associated with chronic allergic asthma.METHODS: Mice which develop chronic airway remodeling (A/J) were compared to mice that develop non-progressive asthma (BALB/c) following intranasal ovalbumin (2 mg/ml; 25 uL: 3x/week for 3 months) challenge or saline (control). To determine the effect of cysteinyl leukotrienes on bone marrow function, ovalbumin and saline treated mice were given biodegradable pellets containing a cysteinyl leukotriene receptor antagonist (montelukast; 10 mg/kg/day) or placebo. End points included bone marrow eosinophil numbers. CD4+, CD8+, Treg (CD4+ Foxp3+CD25+) cell numbers were ascertained by flow cytometry. Statistical analysis was performed by t test.RESULTS: Bone marrow eosinophils numbers were elevated in ovalbumin-challenged A/J mice as compared to saline control (p = 0.012). Ovalbumin-challenged A/J mice had decreased CD4+ (p = 0.03) and CD8+ cells (p < 0.0001) bone marrow T cells as compared to controls. An abrogation in elevation of eosinophils (p = 0.002), and drop in CD4+ cells (p = 0.004) and CD8+ cells (p = 0.004) occurred in montelukast treated ovalbumin-challenged A/J mice. Treg cells decreased in ovalbumin-challenged A/J mice as compared to saline controls (p = 0.024). In comparison, no changes were noted in bone marrow eosinophil, CD4+, CD8+ or Treg cell numbers in ovalbumin-challenged or monteluakst treated BALB/c mice (p > 0.05) as compared to controls.CONCLUSIONS: Decreased bone marrow T cell numbers and accelerated eosinophilopoiesis are associated with ovalbumin exposure in mice which develop airway remodeling. These changes are cysteinyl leukotriene dependent. These bone marrow changes are not found in mice which do not develop airway remodeling. RATIONALE: To investigate the role of cysteinyl leukotrienes in altered bone marrow eosinophil and T cell numbers associated with chronic allergic asthma. METHODS: Mice which develop chronic airway remodeling (A/J) were compared to mice that develop non-progressive asthma (BALB/c) following intranasal ovalbumin (2 mg/ml; 25 uL: 3x/week for 3 months) challenge or saline (control). To determine the effect of cysteinyl leukotrienes on bone marrow function, ovalbumin and saline treated mice were given biodegradable pellets containing a cysteinyl leukotriene receptor antagonist (montelukast; 10 mg/kg/day) or placebo. End points included bone marrow eosinophil numbers. CD4+, CD8+, Treg (CD4+ Foxp3+CD25+) cell numbers were ascertained by flow cytometry. Statistical analysis was performed by t test. RESULTS: Bone marrow eosinophils numbers were elevated in ovalbumin-challenged A/J mice as compared to saline control (p = 0.012). Ovalbumin-challenged A/J mice had decreased CD4+ (p = 0.03) and CD8+ cells (p < 0.0001) bone marrow T cells as compared to controls. An abrogation in elevation of eosinophils (p = 0.002), and drop in CD4+ cells (p = 0.004) and CD8+ cells (p = 0.004) occurred in montelukast treated ovalbumin-challenged A/J mice. Treg cells decreased in ovalbumin-challenged A/J mice as compared to saline controls (p = 0.024). In comparison, no changes were noted in bone marrow eosinophil, CD4+, CD8+ or Treg cell numbers in ovalbumin-challenged or monteluakst treated BALB/c mice (p > 0.05) as compared to controls. CONCLUSIONS: Decreased bone marrow T cell numbers and accelerated eosinophilopoiesis are associated with ovalbumin exposure in mice which develop airway remodeling. These changes are cysteinyl leukotriene dependent. These bone marrow changes are not found in mice which do not develop airway remodeling.

Since the anthrax attacks of 2001, the emphasis on developing animal models of aerosolized select agent pathogens has increased. Many scientists believe that nonhuman primate models are the most appropriate to evaluate pulmonary response to, vaccines for, and treatments for select agents such as Yersinia pestis (Y. pestis), the causative agent of plague. A recent symposium concluded that the cynomolgus macaque (Macaca fascicularis) plague model should be characterized more fully. To date, a well-characterized cynomolgus macaque model of pneumonic plague using reproducible bioaerosols of viable Y. pestis has not been published. In the current study, methods for creating reproducible bioaerosols of viable Y. pestis strain CO92 (YpCO92) and pneumonic plague models were evaluated in 22 Indonesian-origin cynomolgus macaques. Five macaques exposed to doses lower than 250 CFU remained free of any indication of plague infection. Fifteen macaques developed fever, lethargy, and anorexia indicative of clinical plague. The 2 remaining macaques died without overt clinical signs but were plague-positive on culture and demonstrated pathology consistent with plague. The lethal dose of plague in humans is reputedly less than 100 organisms; in this study, 66 CFU was the dose at which half of the macaques developed fever and clinical signs (ED50), The Indonesian cynomolgus macaque reproduces many aspects of human pneumonic plague and likely will provide an excellent model for studies that require a macaque model.

Clostridium piliforme is an obligate intracellular bacterium that causes enterohepatic disease in many animal species. C. piliforme infections are commonly subclinical in laboratory rats and mice, and little is known about host regulation of disease or of the effects of C. piliforme infections on investigations that use subclinically infected animals. To assess host regulation of subclinical C. piliforme infections and the effects of those infections on laboratory mice, the expression of the pro-inflammatory cytokines tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) was evaluated at 0, 1, 3, 7, 14 and 28 days after inoculation with C. piliforme. Subclinical infection was induced in weanling C. piliforme-susceptible DBA/2 or -resistant C57BL/6 mice with either a toxic or a non-toxic C. piliforme strain. Hepatic lesions and bacteria were demonstrated histologically in both mouse strains for 14 days after inoculation with the toxigenic bacterial strain, but were never demonstrated histologically following inoculation with the non-toxigenic strain. Hepatic TNF-alpha and IFN-gamma mRNA and serum protein levels were similarly elevated in both mouse strains 1 day after inoculation with both C. piliforme strains, as evaluated by reverse transcription PCR and enzyme-linked immunosorbent assays, respectively. Elevation of IFN-gamma persisted for 14 days after inoculation; TNF-alpha remained elevated at 28 days after inoculation.

Clostridium piliforme is an obligately intracellular bacterium that causes enterohepatic disease in many domestic and laboratory animal species. Susceptibility to infection is known to vary with the host immune status, species and strain, but little is known about specific immune mechanisms that regulate this disease. Subclinical infection was induced in weanling C. piliforme-susceptible DBA/ 2 or resistant C57BL/ 6 mice with either a toxic or a non-toxic C. piliforme isolate. Hepatic lesions and bacteria were evident in both mouse strains for 14 days after inoculation with the toxigenic bacterial isolate, but were never demonstrated following inoculation with the non-toxigenic isolate. All mice demonstrated increased interleukin-6 (IL-6) levels that were largely independent of host strain susceptibility to infection or virulence of the bacterial isolate. The severity of C. piliforme-induced hepatic lesions was increased by polyclonal anti-IL-6 treatment in both resistant (DBA/ 2) and susceptible (C57BL/ 6) mouse strains. These data indicate that IL-6 is important in mediating the course of murine C. piliforme infections but is not involved in determining host susceptibility to acute infection, nor is it influenced by the virulence of the C. piliforme isolate.

Clostridium piliforme induces enterohepatic disease in many domestic and laboratory animal species. Susceptibility to infection is known to vary with the immune status and strain of the host, but little is known about specific immune mechanisms that regulate this disease. To evaluate host control of C. piliforme infection, we examined the role of interleukin-12 (IL-12) both in the control of and in the response to murine C. piliforme infection. For this study, 3-week-old C. piliforme-resistant C57BL/6 or -susceptible DBA/2 mice were infected intravenously with either the toxic H1 or the nontoxic M1 C. piliforme isolate. Serum and liver samples were collected prior to C. piliforme inoculation (day 0) and at days 1, 3, 7, 14, and 28 postinoculation, Evaluation of hepatic IL-12 p40 mRNA expression by reverse transcription-PCR and of total-IL-12 protein levels in serum by enzyme-linked immunosorbent assay revealed that C. piliforme induced elevations in both hepatic p40 mRNA and serum total-IL-12 levels at all times postinoculation. Elevations were similar with both toxic and nontoxic C. piliforme isolates. Levels of total IL-12 in serum were significantly (P < 0.05) higher in C57BL/6 mice than in DBA/2 mice. Additional experiments were performed in which polyclonal antibody treatment was used to neutralize IL-12 in mice of both strains prior to intravenous inoculation with toxic C. piliforme H1-IL-12 neutralization increased the severity of Tyzzer's disease at day 3 postinoculation in both mouse strains, but the degree of increase was greater in C57BL/6 mice than in DBA/2 mice.