Casein Kinase 1 Underlies Temperature Compensation of Circadian Rhythms in Human Red Blood Cells.

Temperature compensation and period determination by casein kinase 1 (CK1) are conserved features of eukaryotic circadian rhythms, whereas the clock gene transcription factors that facilitate daily gene expression rhythms differ between phylogenetic kingdoms. Human red blood cells (RBCs) exhibit temperature-compensated circadian rhythms, which, because RBCs lack nuclei, must occur in the absence of a circadian transcription-translation feedback loop. We tested whether period determination and temperature compensation are dependent on CKs in RBCs. As with nucleated cell types, broad-spectrum kinase inhibition with staurosporine lengthened the period of the RBC clock at 37°C, with more specific inhibition of CK1 and CK2 also eliciting robust changes in circadian period. Strikingly, inhibition of CK1 abolished temperature compensation and increased the Q10 for the period of oscillation in RBCs, similar to observations in nucleated cells. This indicates that CK1 activity is essential for circadian rhythms irrespective of the presence or absence of clock gene expression cycles.

Rhythmic potassium transport regulates the circadian clock in human red blood cells.

Circadian rhythms organize many aspects of cell biology and physiology to a daily temporal program that depends on clock gene expression cycles in most mammalian cell types. However, circadian rhythms are also observed in isolated mammalian red blood cells (RBCs), which lack nuclei, suggesting the existence of post-translational cellular clock mechanisms in these cells. Here we show using electrophysiological and pharmacological approaches that human RBCs display circadian regulation of membrane conductance and cytoplasmic conductivity that depends on the cycling of cytoplasmic K+ levels. Using pharmacological intervention and ion replacement, we show that inhibition of K+ transport abolishes RBC electrophysiological rhythms. Our results suggest that in the absence of conventional transcription cycles, RBCs maintain a circadian rhythm in membrane electrophysiology through dynamic regulation of K+ transport.

Risk factors associated with enteric septicemia of catfish on Mississippi commercial catfish farms.

A gram-negative bacterium, Edwardsiella ictaluri, is the cause of enteric septicemia of catfish (ESC), which is one of the most prevalent bacterial diseases in farm-raised catfish. The objective of this study was to identify risk factors associated with ESC mortalities and are reported by farm personnel. To identify risk factors a catfish management database was developed. The odds ratios (OR) of the final multivariable logistic regression model were: (1) volume of the pond (OR, 0.56), (2) interval from harvest until a mortality event (OR, 1.49), (3) interval from stocking until a mortality event (OR, 0.52), (4) nitrite measured within 14 d of a mortality (OR, 3.49), (5) total ammonia measured within 14 d of a mortality (OR, 20.48), and (6) sum of feed fed for 14 d prior to the disease outbreak (OR, 1.02), all of which were significantly (P ≤ 0.05) associated with ESC occurrence. This study showed that some commonly recorded production variables were associated with ESC outbreaks and if monitored could help identify "at risk" ponds prior to disease outbreaks.

Pond-level risk factors associated with columnaris disease on Mississippi commercial catfish farms.

A large commercial catfish enterprise encompassing over 500 food fish ponds from five farms covering multiple counties in the Mississippi Delta was included in this analysis of columnaris risk factors. A gram-negative bacterium, Flavobacterium columnare, is the cause of columnaris disease and is considered the second-most prevalent bacterial disease in farm-raised catfish. The objective of this study was to determine if pond-level risk factors reported by farm personnel were associated with columnaris disease mortalities. To identify risk factors affecting susceptibility of farm-raised channel catfish Ictalurus punctatus to columnaris disease, a Catfish Management database was developed. Logistic regression was used to model the relationships between probability of columnaris in ponds and risk factors examined. Generalized linear mixed models incorporating hierarchically structured random effects of ponds and one or more fixed-effects risk factors were fitted. In the screening process, each risk factor was evaluated in the basic model as a single fixed-effects factor, and if associated with the outcome (P ≤ 0.20), was retained for development of multivariable models. Two multivariable logistic regression models were constructed from data collected at the pond level by producers. The first was constructed from data in which water quality was not considered. Pond depth and reduced feed consumption for a 14-d period prior to disease outbreaks measured on a per hectare basis were significantly (P ≤ 0.05) associated with columnaris disease. The second, in which water quality variables were also considered, pond depth, reduced feed consumption, shorter intervals from stocking to disease outbreaks, and total ammonia nitrogen were significantly (P ≤ 0.05) associated with columnaris occurrence. This study showed some commonly recorded production variables were associated with columnaris disease outbreaks and, if monitored, could help identify "at risk" ponds before disease outbreaks occur.

A swine model for the evaluation of efficacy of anti-microbial catheter coatings.

A swine model was developed to investigate the efficacy of percutaneous venous catheters with anti-microbial coatings. The catheters used in the study consisted of silver-coated and uncoated catheters, both designed for percutaneous venous access. Five commercial pigs were each implanted with three venous catheters and followed for a period of 90 days. Two of the three catheters were coated and one was uncoated. To evaluate the percutaneous aspects of the catheters in the model, two venous access catheters were implanted percutaneously, parallel to the dorsal midline. These catheters were just caudal to the region that is dorsal to the scapula in each animal. In each case, the catheter to the left of the dorsal midline was silver-coated while the catheter to the right of the dorsal midline was uncoated. A silver-coated catheter was also implanted in the left external jugular vein of each animal and buried subcutaneously in order to evaluate the elution of the coating through the body under venous contact. Over the 90 day period, the concentration of silver in the blood rose to a mean peak level of 23.2 ppb following implantation of the catheters and then decreased after the second post-surgery week. The histological evaluation and macroscopic inspection at necropsy revealed minimal tissue response to both coated and uncoated materials. Data on bacterial growth indicated that bacteria were present at the terminal subcutaneous end of two of the uncoated percutaneous catheters. Based upon serum silver levels, exudate formation, histological examination, and bacterial growth information, the swine model was deemed to be suitable for testing the efficacy of catheters containing anti-microbial coatings.

Lead poisoning and toxicokinetics in a heifer and fetus treated with CaNa2 EDTA and thiamine.

Lead (Pb) poisoning of a pregnant heifer was diagnosed based upon clinical signs (head pressing, blindness, muscle twitching) and a blood lead concentration of 1.73 ppm. Blood and urinary Pb half-lives with CaNa2 EDTA/thiamine therapy were determined to be 2.08 and 1.38 days, respectively. Many cations (Ca, Fe, Zn, Na, Cu), including Pb, were excreted at higher concentrations in urine during therapy. Blood (0.425 ppm) and liver (4.85 ppm) Pb concentrations in the fetus were 71.7% and 84.3% of the same tissue Pb concentrations of the dam, indicating a significant transfer of Pb in utero. Severe polioencephalomalacia was described in the adult, and hepatic lysosomes with metallic electron densities were present in the fetus.

The pathogenesis of quail bronchitis.

To determine the fate of virus and characterize the development of lesions, 1-week-old bobwhite quails (Colinus virginianus) were inoculated intratracheally with 10(6) mean tissue-culture-infective doses of quail bronchitis virus. Quails were killed and necropsied sequentially at 2, 4, 8, 16, and 24 hours postinoculation (PI) and on days 2-10 PI. Virus was first isolated from the lung as early as 2 hours PI, from cecal tonsils and bursa of Fabricius 4 hours PI, and from spleen and liver 8 hours PI. Tissue virus titers were highest on days 4 to 6 PI, corresponding with the severity of histologic lesions. Viral inclusions were present in tracheal mucosal epithelium by day 2 PI. On day 3 PI, tracheal epithelium was deciliated, formed an irregular luminal border, and had more frequent inclusions. On days 4 and 5 PI, tracheal epithelium was partially desquamated, but there were minimal leukocytic infiltrates. Bronchiolar epithelium underwent similar changes, but the leukocytic infiltration was more intense and included lymphocytes and heterophils. There was extension of leukocytic infiltrates into surrounding lung that was most extensive on day 3 PI. Hyperplasia of splenic macrophages was first identified on day 2 PI and peaked by day 5 PI.

Morphological effects of arthroscopic partial synovectomy in horses.

Gross and microscopic effects of arthroscopic partial synovectomy on synovium and articular cartilage of middle carpal joints were studied in 15 horses. A 7-mm diameter motorized synovial resector was inserted into each middle carpal joint and arthroscopic partial synovectomy and lavage or arthroscopic lavage alone was performed. Study periods were 0 (three horses), 16 (three horses), and 30 days (six horses). No gross evidence of degenerative joint disease was observed at day 16 or 30. At 30 days, resected areas lacked villi and there was deposition of fibrin on the synovial surface with varying amounts of newly formed fibrovascular tissue. Thirty days after arthroscopic synovectomy, normal synovium had not formed in equine middle carpal joints.

Experimental infection of bobwhite quail with Indiana C adenovirus.

Bobwhite quails (Colinus virginianus) were inoculated intratracheally, intraperitoneally, or subcutaneously with Indiana C adenovirus at 1, 3, 6, or 9 weeks of age. Mortality rates were 33-100% in quails inoculated at 1 or 3 weeks of age and 0-10% in quails inoculated at 6 or 9 weeks of age. Gross and histologic lesions included necrotizing tracheitis and bronchitis with pneumonia, necrotizing hepatitis and splenitis, and lymphoid depletion of the bursa of Fabricius; these were consistent with quail bronchitis. Indiana C is highly pathogenic in bobwhite quails and cannot be recommended as a vaccine to prevent quail bronchitis.

Reovirus associated with excessive mortality in young bobwhite quail.

Multiple submissions of bobwhite quail (Colinus virginianus) were received for diagnosis from a commercial-size quail operation. The history and clinical signs included respiratory distress, lethargy, and substantial mortality. Reovirus was recovered from quail in the first submission, and both reovirus and adenovirus were isolated from later submissions. To determine the pathogenicity of the isolated reovirus, the initial isolate was inoculated into young quail from a different source. Those inoculated by the subcutaneous route became lethargic, and more than half died during the 2 weeks of the trial. Reovirus was recovered from a high percentage of those inoculated by this route. To the authors' knowledge, the isolation of reovirus from quail has rarely been reported, and reovirus has never before been suggested as a pathogen in this species.

Further characterization of an avian adenovirus associated with inclusion body hepatitis in bobwhite quails.

An adenovirus (isolate 1452) associated with inclusion body hepatitis of bobwhite quails (Colinus virginianus) was characterized as a group I, serotype 1 avian adenovirus and was indistinguishable from quail bronchitis virus. Bobwhite quails were inoculated via the intratracheal or intraperitoneal route with 10(6) mean tissue-culture infective dose of isolate 1452 at 1, 3, 6, or 9 weeks of age. Lesions produced by either route of inoculation were similar to those of quail bronchitis and included necrotizing tracheitis, proliferative and necrotizing bronchitis and pneumonia, and multifocal necrotizing hepatitis, necrotizing splenitis with or without hyperplasia of splenic macrophages, and lymphoid necrosis and atrophy of the bursa of Fabricius. Basophilic intranuclear viral inclusions were present in respiratory mucosal epithelium, hepatocytes and occasionally bile duct epithelium, and the mucosal epithelium overlying follicles of the bursa. Results indicate that isolate 1452 is a field isolate of quail bronchitis virus and that inclusion body hepatitis of bobwhite quails is a manifestation of quail bronchitis.

Pathology of experimentally induced quail bronchitis.

Bobwhite quails (Colinus virginianus) were inoculated with 10(6) mean tissue-culture infective dose of quail bronchitis virus at 1, 3, 6, or 9 weeks of age by intratracheal, intraperitoneal, or subcutaneous routes. Quails developed necrotizing tracheitis, proliferative and necrotizing bronchitis and pneumonia; multifocal necrotizing hepatitis; necrotizing splenitis, with or without hyperplasia of splenic mononuclear phagocytes; bursal lymphoid necrosis; and bursal atrophy. Lesions were more extensive and severe in quails inoculated at 1 or 3 weeks of age than in older quails. Large intranuclear inclusions, characteristic of adenovirus infection, were identified in trachea, lung, liver, and bursa of Fabricius. This is the first report of the histopathology of experimentally induced quail bronchitis.

Observations of experimentally induced quail bronchitis.

Quail bronchitis was experimentally reproduced in captive-reared bobwhite quails (Colinus virginianus). Quails were inoculated with 10(6) mean tissue culture infective doses of quail bronchitis virus at 1,3,6, or 9 weeks of age by the intratracheal, intraperitoneal, or subcutaneous route. Clinical signs were minimal, but occasionally birds were ruffled, exhibited open-mouthed breathing, and developed "snicks." Mortality rates of quails inoculated at 1 or 3 weeks ranged from 7% to 87%. Quails inoculated at 6 or 9 weeks of age had mortality rates from 0% to 20%. Mean body weights of survivors that had been inoculated at 3 or 6 weeks were significantly less than those of controls (P less than 0.05). No significant differences in body weight were detected between quails inoculated at 1 or 9 weeks and their uninoculated controls. Antibodies to group I adenovirus were detected by agar gel precipitation in 87.5% of birds that survived infection.

Adenoviral pancreatitis in guinea fowl (Numida meleagris).

Necrotizing pancreatitis was observed in 2-week-old Guinea fowl submitted for necropsy and histopathology. Intranuclear inclusion bodies seen histologically in acinar epithelium were examined by electron microscopy and found to contain viruses resembling adenovirus. Adenovirus was isolated in embryonated eggs from the pancreata of affected birds. The adenovirus isolated was not neutralized by chicken antisera developed against 10 known serotypes of group 1 avian adenoviruses.

Inclusion body hepatitis in bobwhite quail (Colinus virginianus).

Farm-reared bobwhite quails less than 3 weeks of age experienced high mortality (250 of 400). At necropsy, these birds had multiple 1-to-2-mm pale foci throughout their livers. Histologically, these foci varied from acute hepatocellular necrosis without an inflammatory response to necrosis with infiltrates of mononuclear inflammatory cells and some heterophils. Hepatocytes adjacent to affected areas had large basophilic intranuclear inclusions. A group I avian adenovirus was isolated from affected livers.