Fatal epizootic equine herpesvirus 1 infections in new and unnatural hosts

In a zoological collection, four black bears (Ursus americanus) died from neurological disease within six months. Independently in a geographically different zoo, two Thomson's gazelles (Eudorcas thomsoni) and 18 guinea pigs (Cavia porcellus f. dom.) suffered from neurological disorders. In addition, guinea pigs showed abortions and stillbirths. All affected animals displayed a non suppurative meningoencephalitis with intranuclear inclusion bodies. Immunohistology demonstrated equine herpes virus antigen and ultrastructurally herpes viral particles were detected. Virus isolation and molecular analysis identified neurotropic equine herpesvirus (EHV) 1 strains in both epizootics. There is serological evidence of a possible virus transmission from other equids to the affected animals. Cross-species transmission of EHV-1 should be considered in the management of captive wild equids and ungulates, particularly with respect to fatal disease in irreplaceable species.     

Honey-bee abdomen assays of hemolymph from stressed and externally poisoned American cockroaches

Blood from cockroaches stressed by having their mouthparts sealed or by being dehydrated by contact with silica aerogel, administered into the opened wounds of freshly excised honey bee abdomens, produced neuromuscular reaction that was monitored and recorded as characteristic myograms. When blood became too viscous or unobtainable during the terminal stages of stress, coxal muscle was substituted. Abdomens used for assay were also used for toxicological studies, comparing their survival time with untreated abdomens. Intact and decapitated cockroaches were equally desiccated by contact with silica aerogel to determine if presence or absence of the coordinating center had any bearing on stress. Fragments of coxal muscle from the intact cockroaches deactivated 10 bee abdomens in 15 hr while coxal muscle from the decapitated cockroaches deactivated only one out of 10 abdomens. Blood from cockroaches poisoned by oral administrations of boric acid solution was readily available, clear, and free-flowing, and produced myograms showing periods of lethargy followed by deep convulsions. Portions of these myograms resembled symptoms of lethargy and convulsions produced by boric acid solution when it was administered directly into the bee abdomens.     

Silica aerogel and boric acid against cockroaches: External and internal action

American cockroaches, Periplaneta americana (L.), and German cockroaches, Blattella germanica (L.), ingested large quantities of powder (silica aerogel and boric acid) in the process of preening their appendages. Their crops were greatly distended by the powder, but the denticles of the armarium of the proventriculus permitted the movement of only very small quantities of silica aerogel into the remainder of the alimentary tract. Boric acid likewise passed the armarium in very small quantities and apparently only in solution.There was no significant difference in the rate of mortality of both species of cockroaches confined with deposits of silica aerogel SG-68, whether their mouthparts were sealed with paraffin wax or left unsealed. Ingested powder did not increase the rate of water loss. Cockroaches with unsealed mouthparts died more rapidly on deposits of boric acid than those with sealed mouthparts, as might be expected of a toxic compound. However, cockroaches with sealed mouthparts were strikingly affected by boric acid, indicating cuticular penetration by that compound. Penetration within the integument, in the gross body contents, in the alimentary tract, and in the feces was confirmed by a boric acid flame test.     

Exogenous induction of cerebral beta-amyloidogenesis is governed by agent and host

Protein aggregation is an established pathogenic mechanism in Alzheimer's disease, but little is known about the initiation of this process in vivo. Intracerebral injection of dilute, amyloid-beta (Abeta)-containing brain extracts from humans with Alzheimer's disease or beta-amyloid precursor protein (APP) transgenic mice induced cerebral beta-amyloidosis and associated pathology in APP transgenic mice in a time- and concentration-dependent manner. The seeding activity of brain extracts was reduced or abolished by Abeta immunodepletion, protein denaturation, or by Abeta immunization of the host. The phenotype of the exogenously induced amyloidosis depended on both the host and the source of the agent, suggesting the existence of polymorphic Abeta strains with varying biological activities reminiscent of prion strains.     

Photonic crystal light collectors in fish retina improve vision in turbid water

Despite their diversity, vertebrate retinae are specialized to maximize either photon catch or visual acuity. Here, we describe a functional type that is optimized for neither purpose. In the retina of the elephantnose fish (Gnathonemus petersii), cone photoreceptors are grouped together within reflecting, photonic crystal-lined cups acting as macroreceptors, but rod photoreceptors are positioned behind these reflectors. This unusual arrangement matches rod and cone sensitivity for detecting color-mixed stimuli, whereas the photoreceptor grouping renders the fish insensitive to spatial noise; together, this enables more reliable flight reactions in the fish's dim and turbid habitat as compared with fish lacking this retinal specialization.