Antibodies against Affinity-Purified, Surface-Exposed Outer Membrane Proteins of Edwardsiella ictaluri Block Invasion into Fathead Minnow Epithelial Cells

Surface-exposed outer membrane proteins (OMPs) of Edwardsiella ictaluri were isolated by selective solubilization of inner membrane proteins from total membrane preparations. Purification of biotin-labeled, insoluble, surface-exposed proteins using streptavidin columns was performed, and single-dimension sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) showed four major OMPs, with apparent molecular weights of 22, 31, 59, and 72 kilodaltons (kDa). Purified surface-exposed proteins corresponded to proteins isolated from total outer membrane preparations resolved by SDS–PAGE, showing that surface-exposed proteins are within the outer membrane fraction and can be successfully isolated using affinity purification. Polyclonal antiserum against these surface-exposed OMPs was produced in New Zealand white rabbits, and protein recognition was determined using in-gel Western analysis. Rabbit antisera recognized three of the four protein bands (22, 31, and 59 kDa). The produced antisera blocked invasion of cells from fathead minnow Pimephales promelas by virulent E. ictaluri, showing that at least one of these proteins is involved in initial bacterial–host cell interactions

Detection of Early Stages of Myxobolus Cerebralis in Fin Clips from Rainbow Trout (Onchorynchus mykiss)

A nested polymerase chain reaction (PCR) assay was used to detect early stages of Myxobolus cerebralis in caudal and adipose fin samples from rainbow trout (RT). To determine sensitivity, groups of 10 RT were exposed to 2,000 M. cerebralis triactinomyxons/fish for 1 hour at 15 degrees C and subsequently moved to clean recirculating water. Fish were held for 2 and 6 hours and 1, 2, 3, 5, 7, 10, 30, and 60 days before sampling by nonlethal fin biopsy. Nested PCR performed on fin clips showed that M. cerebralis DNA was detected in caudal fin tissue in 100% of fish up to 5 days postexposure. At days 7 and 10 postexposure, 80% of fish were positive, and at 60 days postexposure, 60% of fish were positive using this technique. Conversely, testing on adipose fin clips proved less sensitive, as positive fish dropped from 80% at day 7 to below 20% at day 10 postinfection. Since detection of M. cerebralis infection using caudal fin samples coupled with nested PCR is an effective method for detection of early parasite stages, use of this technique provides for accurate, nonlethal testing

Development of a New Tacaribe Arenavirus Infection Model and Its Use to Explore Antiviral Activity of a Novel Aristeromycin Analog

Background A growing number of arenaviruses can cause a devastating viral hemorrhagic fever (VHF) syndrome. They pose a public health threat as emerging viruses and because of their potential use as bioterror agents. All of the highly pathogenic New World arenaviruses (NWA) phylogenetically segregate into clade B and require maximum biosafety containment facilities for their study. Tacaribe virus (TCRV) is a nonpathogenic member of clade B that is closely related to the VHF arenaviruses at the amino acid level. Despite this relatedness, TCRV lacks the ability to antagonize the host interferon (IFN) response, which likely contributes to its inability to cause disease in animals other than newborn mice. Methodology/Principal Findings Here we describe a new mouse model based on TCRV challenge of AG129 IFN-α/β and -γ receptor-deficient mice. Titration of the virus by intraperitoneal (i.p.) challenge of AG129 mice resulted in an LD50 of ∼100 fifty percent cell culture infectious doses. Virus replication was evident in the serum, liver, lung, spleen, and brain 4–8 days after inoculation. MY-24, an aristeromycin derivative active against TCRV in cell culture at 0.9 µM, administered i.p. once daily for 7 days, offered highly significant (P\u3c0.001) protection against mortality in the AG129 mouse TCRV infection model, without appreciably reducing viral burden. In contrast, in a hamster model of arenaviral hemorrhagic fever based on challenge with clade A Pichinde arenavirus, MY-24 did not offer significant protection against mortality. Conclusions/Significance MY-24 is believed to act as an inhibitor of S-adenosyl-L-homocysteine hydrolase, but our findings suggest that it may ameliorate disease by blunting the effects of the host response that play a role in disease pathogenesis. The new AG129 mouse TCRV infection model provides a safe and cost-effective means to conduct early-stage pre-clinical evaluations of candidate antiviral therapies that target clade B arenaviruses

Comparison of Injuries to Coyote From 3 Types of Cable Foot-Restraints

We compared injury rates among captured coyotes (Canis latrans) to determine if modifications to cable foot-restraints would decrease resulting injuries. Mean International Standardization Organization’s injury scores of coyotes caught in 3 types of cable foot-restraints were 22.2, 37.9, and 60.4 (F2,41 = 4.63, P = 0.015) for a chain-loop, standard cable, and sleeved cable, respectively. These results may be important for trappers and researchers to consider when using a cable foot-restraint device to capture wildlife

PuntaToro virus (Bunyaviridae, Phlebovirus) infection in mice: strain differences inpathogenesis and host interferon response

The Adames strain of Punta Toro virus (PTV-A, Bunyaviridae, Phlebovirus) causes an acute lethal disease in hamsters and mice. The Balliet strain of the virus (PTV-B) is generally considered to be avirulent. The difference in hamster susceptibility is likely due to the ability of PTV-A to suppress interferon (IFN)-β similarly to that described for Rift Valley fever virus. Here we investigated strain differences in PTV pathogenesis and the IFN response in mice. Although PTV-B infection in mice did not induce systemic IFN-β release, primary macrophages produced dramatically higher levels when exposed to the virus in culture. The importance of IFN in resistance to PTV infection was borne out in studies employing STAT-1 knock-out mice. Also, a number of genesspecific to IFN response pathways were upregulated in PTV-B-infected macrophages. Our findings provide new insights into the type I IFN response during PTV infection in the mouse model of phleboviral disease