The Effect of Temperature, Pressure and Chlorine Concentration of Spray Washing Water on Numbers of Bacteria on Lamb Carcases

Combined analysis of three experiments showed that when lamb carcases with initial bacterial numbers of between logi₁₀3.29 and 4.22/cm² were spray washed, statistically significant reductions in bacterial numbers of log₁₀O.5 were obtained when the spray wash water temperature was > 57°C, and reductions of log₁₀1.0 were obtained when the temperature was ≥ 80°C. Reductions at all temperatures were enhanced by log₁₀0.66 when the water contained 30 µg/ml chlorine, but increasing the concentration to 450 µg/ml reduced bacterial numbers only by a further log₁₀0–29. At highly contaminated sites increasing the duration of spraying from 30 to 120 s significantly increased the reductions obtained when water containing added chlorine was used. Reductions in bacterial numbers after spray washing with pressures of 3.5, 5.6. 7.7 kg/cm² were not significantly different.     

Effects of infection with a granulosis virus on larval growth, development and ecdysteroid production in the cabbage looper, Trichoplusia ni

ABSTRACT. Granulosis virus-infected Trichoplusia ni (Hûbner) larvae exhibited an increased larval life span with no supernumerary moult and no pupation. Weight gain was not affected. Insects infected shortly after hatching were slower in reaching the fourth and fifth stadia than were control insects. Haemolymph ecdysteroid titres were lower in virus-infected insects than control insects, but these differences were only significant ( P <0.05) in the fifth stadium. Electron microscopic examination of the pro thoracic glands revealed extensive granulosis virus infection, and glands from virus-infected insects produced no RIA-detectable ecdysteroids in vitro. Injection of 20-OII-ecdysone into virus-infected larvae at various concentrations and times did not induce pupation.     

Introduction of the non-indigenous amphipod Gammarus pulex alters population dynamics and diet of juvenile trout Salmo trutta

Summary 1. The amphipod Gammarus pulex , introduced to Irish rivers with the aim of enhancing trout feeding, is displacing the native Gammarus duebeni celticus . These two species are generally associated with different environmental conditions and macroinvertebrate communities, confounding assessment of effects of the invader as compared with the native on fish populations. Here, we uncouple effects of the two Gammarus species from environmental gradients.
2. A weir dissects a lowland stretch of the River Lissan, slowing the upstream invasion by G. pulex and resulting in contiguous G. pulex , mixed species and G. d. celticus reaches. Total invertebrate abundance and biomass in the benthos were significantly higher in the G. pulex reach, driven by high invader abundance, with low abundance of other taxa. Gammarus pulex was particularly prominent in night-time drift.
3. Correspondingly, densities and biomass of 0+ trout were significantly higher in the G. pulex reach, while instantaneous loss rates were lower. Fish growth rates were similar among the three reaches.
4. In the G. pulex reach, this invader dominated the diet of 0+ trout, leading to ingestion of significantly higher invertebrate biomass than fish in the other reaches. Fish generally preyed on Gammarus in proportion to its abundance, but exhibited some positive selection for G. pulex in the invaded reach.
5. The negative effects of the invader on native invertebrates are contrasted with positive effects on juvenile trout. This indicates changes in energy flux after invasion, with differential resource use or assimilation by G. pulex probable underlying mechanisms. As the frequency of amphipod invasions increases globally, investigations of their role as strong interactors at multiple levels of ecological organisation is required if the consequences of deliberate and unintentional introductions are to be predicted, and ultimately, prevented.     

Identification of circulating murine CD34+OCN+ cells

Background aims

Previous studies identified a circulating human osteoblastic population that expressed osteocalcin (OCN), increased following fracture and pubertal growth, and formed mineralized colonies in vitro and bone in vivo. A subpopulation expressed CD34, a hematopoietic/endothelial marker. These findings led to our hypothesis that hematopoietic-derived CD34⁺OCN⁺ cells exist in the circulation of mice and are modulated after fracture.