Identification of Synapomorphic Characteris in the Genus Sarcocystis Based on 18S rDNA Sequence Comparison

ABSTRACT. In order to further investigate synapomorphic characters in the genus Sarcocystis , the small subunit ribosomal RNA gene sequences of Sarcocystis capracanis and Sarcocystis moulei were determined and used to infer the phylogenetic position of these two organisms within the cyst-forming coccidia. Phylogenies derived using distance, maximum parsimony and maximum likelihood methods demonstrated that S. capracanis groups with Sarcoystis tenella and Sarcocystis arieticanis as a clade that shares the characteristic of using canids as their definitive host. S. moulei was shown to group with Sarcocystis gigantea and Sarcocystis fusiformis as a clade that shares the characteristic of using felids as their definitive host.     

How tetrapods feed in water: a functional analysis by paradigm

Mechanical theory is used to erect a paradigm predicting the manipulations used by carnivorous aquatic amphibians, reptiles, birds and mammals to catch, subdue, process and swallow their prey. These predictions are confirmed by observational evidence. Most aquatic predatory tetrapods use long, prehensile tooth-armed jaws as pincer jaws to snap shut onto the prey and catch and kill it, although some use the flexibility of long necks in spear fishing and some odontocetes may stun prey with sonar. Most do not have cutting or nipping dentitions as these cannot be used on prey which is freely floating. They use caniniform dentition to hold and kill prey, or in some cases crushing dentition to break open hard-shelled prey. They dismember prey by dynamic loading, snatching bites so quickly that the prey tears. They use shake feeding, shaking the prey apart from side to side above the water. If the prey is too large to lift above the water they use twist feeding, twisting pieces off. Small pieces are easily swallowed but larger pieces are held above the water and swallowed by tilting the head back in gravity feeding, or by jerking the head back and forth in incrtial feeding. Some animals use mobile jaws to pull prey back into the mouth in ratchet feeding. Filter feeding evades these problems by feeding on very small prey. The use of paradigms in functional analysis is discussed with special reference to this work. The paradigm method is shown to be the most suitable one. There has been repeated convergent and parallel evolution of adaptations to feed in water.     

Measurement of immunoreactive cytochrome P450 2E1 in human leucocytes

We describe initial results on a Western blotting method, using a ployclonal antibody and chemiluminescence detection, for the measurement of cytochrome P450 2E1 in human lymphocytes. The method has been used to study the levels of 2E1 in lymphocytes isolated from 5 ml blood samples collected from a small group of well-controlled type 1 diabetics and healthy individuals. The described method offers increased sensitivity compared with a previously published method and does not need in vitro culturing of the lymphocytes prior to 2E1 measurement. The apparent molecular weight of the lymphocyte P450 2E1 was 55 kDa. There was approximately a six-fold difference in expression levels of 2E1 detected by this immunochemical technique across the study population.     

Effects of insect herbivory on early plant succession: comparison of an English site and an American site

We examined the survival, size, and agonistic behaviour of faster and slower developing rainbow trout ( Salmo gairdneri ) in an artificial stream channel with a simulated redd. The analysis was performed at two levels: between three full-sib families genetically marked at a hexosaminidase locus, and within families segregating for a regulatory allele Pgml-t(b) that is associated with faster developmental rate. The families differed significantly in their hatching times but showed little variation in emergence times. Fishes with the Pgml-t(b) allele hatched and emerged significantly earlier than their full-sibs without the allele. Despite the mortality of at least 50% of emerged fishes in the selection experiment, there was no significant difference in survival between either the three families or fishes with different genotypes at the Pgml-t locus. However, fishes from the faster developing family and those with the Pgml-t(b) allele had significantly higher levels of agonistic behaviour and had a tendency to be larger than slower developing individuals.