Bovine Diarrhea Virus

Marked cytopathic changes were induced by challenge with Newcastle disease (ND) virus in bovine testicle or kidney cell cultures which were previously infected with non-cytopathogenic strains of bovine diarrhea (BD) virus. No cytopathic changes were induced by ND virus in similar cells not infected with BD virus. The development of cytopathic effect was shown to be associated with enhancement of ND virus replication. This exalting effect of BD virus appears to be dependent on infectivity, since the effect was inhibited when infection of the cells with BD virus was blocked by specific antiserum. Various factors involved in the phenomenon were investigated and an in vitro method (END) for the assay of BD virus and its antibodies was developed. The use of this method eliminates the difficulties in recognizing non-cytopathogenic strains of BD virus which hampered systematic investigations of the nature and behavior of BD virus as well as of the natural history and pathogenesis of the infection in cattle.     

Bovine Epizootic Fever

It was found that the ruins of Bovine Epizootic Fever appeared to be RNA as its replication was not inhibited by 5-iodo-2′-deoxyuridine. It had a buoyant density of 1.196, was not filterable through membrane filter (Millipore Filter Corp. Mass.) of 100 mμ pore size, and was sensitive to ether, chloroform and deoxycholate, was inactivated by trypsin and ultraviolet irradiation, precipitated by protamine sulfate, readily inactivated at pH 3.0, fairly labile at 56 C but readily preserved at —80 C, not stabilized at 50 C by I M MgCl₂, and resisted repeated freeze-thawing. The virus appears not to require a DNA-depcndent RNA synthesis in the host cell for its replication, as chromomycin A3 did not inhibit its replication. Sucrose density gradient centrifugation was unsuitable for purification because of a very poor recovery of infectivity. CsCl equilibrium density gradient centrifugation was successfully used for this purpose, and electron microscopy of the resulting fractions by phosphotungstic negative staining technique revealed virus-like bullet-shape particles, about 140 mμ in length and 80 mμ across, in the fraction of peak infectivity titer. The particle is probably the virion of the virus. These findings suggest relation of the virus to Rhabdoviruses [6], but further studies are necessary. The physicochemical properties of the virus provide additional evidence for similarity of the virus to bovine ephemeral fever virus, and emphasizes the desirability of further detailed comparative studies to decide whether they are one and the same or merely very closely related.     

Disrupting seasonality to control disease outbreaks: The case of koi herpes virus

Common carp accounts for a substantial proportion of global freshwater aquaculture production. Koi herpes virus (KHV), a highly virulent disease affecting carp that emerged in the late 1990s, is a serious threat to this industry. After a fish is infected with KHV, there is a temperature dependent delay before it becomes infectious, and a further delay before mortality. Consequently, KHV epidemiology is driven by seasonal changes in water temperature. Also, it has been proposed that outbreaks could be controlled by responsive management of water temperature in aquaculture setups. We use a mathematical model to analyse the effect of seasonal temperature cycles on KHV epidemiology, and the impact of attempting to control outbreaks by disrupting this cycle. We show that, although disease progression is fast in summer and slow in winter, total mortality over a 2-year period is similar for outbreaks that start in either season. However, for outbreaks that start in late autumn, mortality may be low and immunity high. A single bout of water temperature management can be an effective outbreak control strategy if it is started as soon as dead fish are detected and maintained for a long time. It can also be effective if the frequency of infectious fish is used as an indicator for the beginning of treatment. In this case, however, there is a risk that starting the treatment too soon will increase mortality relative to the case when no treatment is used. This counterproductive effect can be avoided if multiple bouts of temperature management are used. We conclude that disrupting normal seasonal patterns in water temperature can be an effective strategy for controlling koi herpes virus. Exploiting the seasonal patterns, possibly in combination with temperature management, can also induce widespread immunity to KHV in a cohort of fish. However, employing these methods successfully requires careful assessment to ensure that the treatment is started, and finished, at the correct time.     

Ibaraki Virus,an Agent of Epizootic Disease of Cattle Resembling Bluetongue

Outbreaks of an acute febrile disease of cattle occurred in Japan in 1959 and 1960. Its occurrence was limited in late summer and autumn, and in Kyushu, Shikoku and Honshu roughly south of 37 degrees north latitude, suggesting a close correlation of the incidence with the climatic conditions, hence a possibility of the presence of arthropod vector. The disease was characterized by fever and lesions affecting the mucous membrane and skin, musculature and vascular system. Degeneration of striated muscles was observed in the esophagus, larynx, pharynx, tongue and skeletal muscular system. Edema and hemorrhage were marked in the mouth, lips, abomasum, coronets etc., occasionally followed by degeneration of the epithelium leaving erosions or ulcerations. Severe lesions affecting the esophageal and laryngopharyngeal musculature caused deglutitive difficulty which in turn resulted in dehydration and emaciation, and occasionally in aspiration pneumonia, constituting the major causes of death of the affected animals. These findings indicate that the disease resembles bluetongue in sheep and cattle. The clinical materials obtained from natural cases induced a clinical illness when inoculated into calves, and the disease was transmitted serially in calves by intravenous inoculation of the blood obtained at the height of febrile reaction. The experimentally produced disease was clinically and pathologically indistinguishable from the natural disease.     

Leucine aminopeptidase during meiotic development.

We found a leucine aminopeptidase (LAP; EC 3.4.11.1) to be abundant in meiotic prophase tissue of a basidiomycete, Coprinus cinereus. After direct purification of the aminopeptidase component from meiocytes, we cloned the gene by degenerate PCR using partial amino-acid sequences of the purified enzyme and 5' and 3' RACE. It was homologous to the eukaryotic leucine aminopeptidase gene. The recombinant protein possesses the characteristic activities of a Coprinus leucine aminopeptidase (CoLAP) with a molecular mass of 52.4 kDa, and forms a homohexamer. Northern blot and spatial distribution analysis by immunohistochemical staining indicated CoLAP to be abundant in meiotic prophase cells and the supporting cells around meiocytes, but scarce in mycelium cells. Interestingly, from zygotene to pachytene, CoLAP was mostly present in supporting cells around meiocytes, but from diplotene onwards, it was plentiful in meiocytes themselves, suggesting that its expression is required to control some of the biochemical events at meiotic prophase. Moreover, the strong expression of CoLAP mRNA immediately after treatment with methyl methanesulfonate in mycelium implies that CoLAP has a role in somatic DNA repair.     

Tim4 recognizes carbon nanotubes and mediates phagocytosis leading to granuloma formation

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