Resistance of Calves to Reinfection with Eimeria bovis

SYNOPSIS. An immunity to reinfection with E. bovis was demonstrated in 3 experiments involving 60 calves. This immunity develops rapidly, as indicated by resistance to a challenge given 14 days after the immunizing inoculation. In 3 groups of 3 to 6 young calves each, immunity was still present to a moderate degree 2 to 3 months after inoculation; in one group of 5 animals about a year old there was apparently a high degree of immunity about 7 months after the last inoculation. In one experiment an immunizing inoculum of 10,000 oöcysts did not produce as much immunity as 50,000 oöcysts. In 2 experiments there appeared to be little difference in the immunity produced by a single inoculation of 50,000 as compared with 100,000 oöcysts, but inoculation with 100,000 oöcysts, resulted in substantially longer and more severe illness than 50,000 oöcysts. There appeared to be no appreciable difference in clinical symptoms or development of immunity between calves given a single immunizing inoculum and those given the same number of oöcysts in 5 equal inocula on successive days. Treatment with sulfamethazine and sulfamerazine (Merameth) 13 to 15 days after inoculation alleviated the clinical symptoms of coccidiosis without interfering appreciably with the development of immunity. In one experiment with 7 calves, no beneficial effect was noted from 1 or 2 transfusions of 500 ml. of plasma and leucocytes from immune calves into 4 calves 1 and 12 days or 11 days after a challenge inoculation.     

What limits a rare alpine plant species? Comparative demography of three endemic species of Myosotis (Boraginaceae)

Abstract Establishing what are the underlying causes of species range limits is of fundamental interest in ecology. We followed the fate of individually mapped plants of three endemic New Zealand high‐alpine species of Myosotis, over a period of 9 years. The species provide contrasts in their geographical range and their demography. Myosotis oreophila Petrie is rare and extremely localized (c. 0.5 ha extent), Myosotis cheesemanii Petrie is regionally endemic, and Myosotis pulvinaris Hook. f. is more widespread. All three occur on the Dunstan Mountains, Central Otago, South Island, New Zealand within a 1‐km radius, and individual plants were followed in four permanent plots. The three species differed in their longevity and in population variability, with the most widespread species (M. pulvinaris) having the lowest survival (61% per year), the fewest old plants (only 3% of plants present in 1993 surviving until 2001), no increase in survival rates with age, and the most variability in total numbers across years. Both of the rare species, M. oreophila and M. cheesemanii, had higher survival (75% and 88%, respectively, per year) especially for older plants, many older plants (20% and 59%, respectively, of 1993 plants surviving until 2001), and lower variability in total numbers across years. These results are consistent with other studies showing that rare plant species tend to have higher inertia than more common congeners. The range limits of M. oreophila showed a high level of spatial constancy on a scale of metres over the 9 years, despite 80% turnover in plants during that time. The M. oreophila population showed lower mean densities of plants near to the population boundaries, identical age‐specific survival rates, but lower flowering probabilities, than the core of the population. We were unable to detect any abiotic differences between inside and outside the M. oreophila range in terms of topography, soil parent materials, microclimate or through manipulation of snow cover. Disturbance may be a factor affecting the distribution of M. cheesemanii but limiting factors for M. oreophila and M. pulvinaris are likely to be biotic (competition, seed limitation, dispersal capacity) and/or historic. Further experimentation is recommended.     

Functional characterisation of the regulation of CAAT enhancer binding protein alpha by GSK-3 phosphorylation of Threonines 222/226

Background  

Glycogen Synthase Kinase-3 (GSK3) activity is repressed following insulin treatment of cells. Pharmacological inhibition of GSK3 mimics the effect of insulin on Phosphoenolpyruvate Carboxykinase (PEPCK), Glucose-6 Phosphatase (G6Pase) and IGF binding protein-1 (IGFBP1) gene expression. CAAT/enhancer binding protein alpha (C/EBPα) regulates these gene promoters in liver and is phosphorylated on two residues (T222/T226) by GSK3, although the functional outcome of the phosphorylation has not been established. We aimed to establish whether CEBPα is a link between GSK3 and these gene promoters.     

The first parasitic Trichoptera

Abstract.

• 1 A parasitoid habit is confirmed in larvae of an Australian micro-caddisfly, Orthotrichia muscari Wells, being the first known incidence of this habit in the order Trichoptera.
• 2 Larvae of O.muscari are non-specific parasites of pupae of other caddisfly species.
• 3 O.muscari is in an Australian/New Guinean/SE Asian species group in Orthotrichia, all members of which probably share the habit. Their larvae and pupae have atypical features that are interpreted as adaptations to their uncharacteristic niche.

     

Flowering dynamics of Orchis morio L. and Herminium monorchis (L.) R.Br, at two sites in eastern England

Information taken from two long-term demographic studies on Orchis morio L. and Herminium monorchis (L.) R.Br, is used to explore some of the factors which influence flowering. The proportion of plants which flowered each year varied considerably between species, flowering in O. morio exceeding 40% in all years except one over an 18 year period; over a 30 year period (1966–95), the number of plants of Herminium in flower never exceeded 36% of the population and no inflorescences were produced in 1977 and 1991. The relationship between flowering in Herminium in a given year and the monthly rainfall and temperature for the current and 3 previous years was analysed using logistic regression. Best fits were obtained using data for the summer months in the previous year, with an increasing flowering rate with rainfall and a decline with temperature. It is hypothesized that drought and high temperatures in the summer reduce leaf area and cause premature senescence and the death of leaves, with the result that not enough carbohydrates are stored to enable plants to support or initiate inflorescences the following year. For species such as Orchis morio which produce leaves in the autumn and remain green, summer drought causes no problems as they have no above ground organs. Factors which influence flowering in this species are as yet unknown.