The role of goats as reservoir hosts for bovine herpes virus 1 under field conditions

Bovine herpesvirus 1 (BoHV1) is the cause of economically significant viral infections in cattle. Respiratory symptoms associated with the infection are known as Infectious Bovine Rhinotracheitis (IBR). Sheep and goats are less sensitive to the infection although their role in inter-species viral transmission under field conditions is subject to controversy. The objective of this study was to investigate seroprevalence of BoHV1 infections in cattle, sheep, and goats raised together for at least a year. Blood serum samples were taken from 226 cattle, 1.053 sheep, and 277 goats from 17 small- to medium-scale farms. BoHV1-specific antibody presence and titers were determined using virus neutralization test. In total, 73 of the 226 cattle (32.3%) were seropositive. The infection was detected in 13 of the 17 farms. Infection rates ranged from 5.8 to 88.8%. Only one of the 1053 sheep (0.09%) was seropositive. However, 58 of the 277 (20.9%) goats were seropositive. Goat samples taken from 8 of the 17 farms were seropositive with infection rates ranging from 17 to 38.9%. Statistical analysis showed a significant correlation in infection rates between cattle and goats but not sheep. These results suggest that goats may be more sensitive to the BHV1 infection than sheep and the role of goats as possible reservoirs for BoHV1 in the control and eradication of BHV1 in cattle should be considered in future studies.

     

Regulation of flower development in Dendrobium crumenatum by changes in carbohydrate contents,water status and cell wall metabolism

The involvement of carbohydrates, water potential, cell wall components and cell wall-based enzymes in regulating flower development in Dendrobium crumenatum was investigated. Plants were subjected to cold treatment to release floral buds from dormancy, and the various parameters were investigated from young floral bud stage till flower senescence. Development of floral buds was accompanied by progressive decrease in concentrations of fructans and starch. Upon full flower opening, concentration of soluble sugars was maximum, accompanied by a more negative water potential. High pectin methylesterase activity was observed during early bud development and decreased thereafter. Significant increase in activities of β-galactosidase, β-mannosidase and β-xylosidase was also observed during floral bud development. The cell walls of sepals and petals were modified extensively during floral bud and flower development, as observed by changes in the amounts of celluloses, hemicelluloses and total pectin. Pectin solubilisation was also observed to commence during early floral bud development. These results indicated that carbohydrate hydrolysis, osmotic changes and cell wall dissolution that began early in young floral buds, all regulated flower development in this sympodial orchid. Possible applications of the findings in the horticultural industry are discussed.     

The physiology of Cymbidium plantlets cultured in vitro under conditions of high carbon dioxide and low photosynthetic photon flux density

Summary

Cymbidium plantlets were grown in vitro under conditions of high CO₂ and low photosynthetic photon flux density using the Miracle Packt culture system. Shoots and roots of plantlets showed differential growth characteristics. Shoot growth was not different in plantlets cultured under CO₂-enriched (CDE) and non-enriched (NCDE) conditions. Root growth was promoted in plantlets cultured under CDE in the presence or absence of 2% sucrose (S) with rockwool (R) as the supporting material. Growth was poor in plantlets cultured in 1% agar. Root growth was best in plantlets cultured under CDE R+S. Sucrose is still an important component for root growth under CDE conditions even though CO₂ can be used as an alternative carbon source. Photosynthetic measurements (CO₂ uptake and total Rubisco activity) showed the presence of active and operational photosynthetic machinery in plantlets cultured under CDE and NCDE conditions. The apparent lack of photoautotrophy (as evident from the lack of starch grains in chloroplasts) in plantlets cultured under NCDE conditions is not the result of a lesser potential for photoautotrophy; rather it is a consequence of sub-optimal CO₂ concentrations within the culture vessels.     

In situ growth and mortality of juvenile Acropora over 2 years following mass spawning in Sekisei Lagoon,Okinawa (24°N)

The growth of Acropora in Sekisei Lagoon was investigated in situ using ceramic coral settlement devices (CSDs) and marine blocks (MBs) with small holes on their surfaces that were deployed prior to a mass spawning event. Acropora that had settled in 10-mm holes on the upper surface of the MBs were found to have grown inwards after 348 days post-mass spawning. After 733 days, the colonies had grown outwards, encrusting the blocks and attaining a maximum diameter of 21.5 mm (3.7 mm). CSDs that had been stacked above each other on frames were separated and observed in situ on 405 and 764 days after mass spawning. After 405 days, the maximum diameter of the encrusting Acropora was 7.6 mm (±2.4 mm), which increased to 19.4 mm (±5.5 mm) after 764 days, with 30% of colonies extending short branches. The length of the branches of Acropora grown on the CSDs fixed to the MBs 3 months after the mass spawning event exceeded the size of the encrusting portion of the colony 629 days after spawning. The mortality of colonies between 1 and 2 years was slight, with the temperatures conducive to coral bleaching that occurred during the study also having only a slight effect.     

An early event in the interferon-induced transmembrane signaling process

Human interferon stimulates a transient two- to threefold increase in the concentration of diacylglycerol and inositol tris-phosphate within 15 to 30 seconds of cell exposure to interferon. Antibodies to interferon inhibit this effect. The stimulation was measurable in isolated cell membranes exposed to interferon. Human alpha and beta, but not gamma, interferon stimulate this increase in cells containing the appropriate interferon receptor. The effect was proportional to the number of interferon receptors. Both the diacylglycerol increase and antiviral effects induced by interferon could be correlated in terms of dose dependence. Thus, a transient diacylglycerol increase is an early event in the interferon-induced transmembrane signaling process.