Detection of aphid remains in predatory insects and spiders by ELISA

An ELISA was developed which would detect and quantify ingested aphids in predators found in and around cereal crops. The detection limit of the assay was less than one hundredth of an homogenised adult aphid. Tests with 13 species of aphid showed that those which had been used as the principal immunogens reacted most strongly in the assay. Nearly a hundred species of invertebrates, both predators and alternative prey, have been tested in the assay and no evidence of significant cross-reaction was found with any of these species or with a number of samples of plant material on which aphids may be found. Aphid material could still be detected in predators which had been stored for up to 7 days in 4% formalin or 70% ethanol.     

Progress in Taxonomy of the Apicomplexan Protozoa

In 1987, 4516 species and 339 genera of the phylum Apicomplexa had been named. They consisted of the gregarines (subclass Gregarinasida) (1624 named species and 231 named genera), the hemogregarines (family Haemogregarinidae) (399 species and 4 genera), the eimeriorins (order Eimeriorida) (1771 species and 43 genera), the hemospororids (order Haemospororida) (444 species and 9 genera), the piroplasmids (order Piroplasmorida) (173 species and 20 genera), and a few others (105 species and 32 genera). The first apicomplexan protozoon was seen by Antony van Leeuwenhoek; in 1674 he saw oocysts of Eimeria stiedai in the gall bladder of a rabbit. The first member of the phylum to be named (by Dufour in 1828) was Gregarina ovata in earwigs. During the quarter century 1826–1850, 41 species and 6 genera of Apicomplexa were named. These numbers increased progressively. In the quarter century 1951–1975, 1873 new species and 83 new genera were named. Data are given for the numbers of named species and genera of apicomplexan protozoa of each group known in 1850, 1875, 1900, 1925, 1950, 1975, and 1987.     

A Comparison of Endogenous Development of Three Isolates of Cryptosporidium in Suckling Mice1

ABSTRACT. Suckling mice were used as a model host to compare the endogenous development of three different isolates of Cryptosporidium: one from a naturally infected calf, one from an immunocompetent human with a short-term diarrheal illness, and one from a patient with acquired immune deficiency syndrome (AIDS) and persistent, life-threatening, gastrointestinal cryptosporidiosis. After oral inoculation of mice with oocysts, no differences were noted among developmental stages of the three isolates in their sites of infection, times of appearance, and duration, morphology, and fine structure. Sporozoites excysted within the lumen of the duodenum and ileum, penetrated into the microvillous region of villous enterocytes, and developed into type I meronts with six or eight merozoites. Type I merozoites penetrated enterocytes and underwent cyclic development as type I meronts or they became type II meronts with four merozoites. Type II merozoites did not exhibit cyclic development but developed directly into sexual forms. Microgamonts produced £16 small, bullet-shaped microgametes, which were observed attaching to and penetrating macrogametes. Approximately 80% of the oocysts observed in enterocytes had a thick, two-layered wall. After sporulating within the parasitophorous vacuole, these thick-walled oocysts passed through the gut unaltered and were the resistant forms that transmitted the infection to a new host. Approximately 20% of the oocysts in enterocytes consisted of four sporozoites and a residuum surrounded only by a single oocyst membrane that ruptured soon after the parasite was released from the host cell. The presence of thin-walled, autoinfective oocysts and recycling of type I meronts may explain why a small oral inoculum can produce an overwhelming infection in a suitable host and why immune deficient persons can have persistent, life-threatening cryptosporidiosis in the absence of repeated oral exposure to thick-walled oocysts.     

The Sporulated Oocysts of Eimeria illinoisensis n. sp. and of Other Species of Eimeria of the Ox

SYNOPSIS. The sporulated oocysts of 12 species of Eimeria occurring in the ox Bos taurus in the United States are described and differentiated. They are E. alabamensis, E. auburnensis, E. bovis, E. brasiliensis, E. bukidnonensis, E. canadensis, E. cylindrica, E. ellipsoidalis, E. illinoisensis n. sp., E. subspherica, E. wyomingensis and E. zuernii. Two other species, not yet found in North America, which are recognized as valid are E. pellita and E. thianethi. The sporulated oocysts of E. illinoisensis n. sp. are ellipsoidal or slightly ovoid, 24–29 by 19–22 μ with a mean of 26.3 by 20.7 μ; their sporocysts are 13–16 by 6–7 μ with a mean of 15.3 by 6.5 μ. This species was found in 3 cattle from one farm in Illinois.     

Mitochondrial DNA control region polymorphisms: genetic markers for ecological studies of marine turtles

We describe a rapid and sensitive method for the detection of population-specific genetic markers in mitochondrial DNA (mtDNA) and the use of such markers to analyse population structure of marine turtles. A series of oligonucleotide primers specific for the amplification of the mtDNA control region in Cheloniid turtles were designed from preliminary sequence data. Using two of these primers, a 384–385-bp sequence was amplified from the 5′ portion of the mtDNA control region of 15 green turtles Chelonia mydas from 12 different Indo-Pacific rookeries. Fourteen of the 15 individuals, including some with identical whole-genome restriction fragment patterns, had sequences that differed by one or more base substitutions. Analysis of sequence variation among individuals identified a total of 41 nucleotide substitutions and a 1-bp insertion/deletion. Comparison with evidence from whole-genome restriction enzyme analysis of the same individuals indicated that this portion of the control region is evolving approximately eight times faster than the average rate and that the sequence analysis detected approximately one fifth of the total variation present in the genome. Restriction enzyme analysis of amplified products from an additional 256 individuals revealed significant geographic structuring in the distribution of mtDNA genotypes among five of the 10 rookeries surveyed extensively. Additional geographic structuring of genotypes was identified through denaturing gradient gel electrophoresis (DGGE) of amplified products. Only two of the 10 rookeries surveyed could not be differentiated, indicating that the Indo-Pacific C. mydas include a number of genetically differentiated populations, with minimal female-mediated gene flow among them. Important applications for genetic markers in the conservation and management of marine turtles include the identification of appropriate demographic units for research and management (i.e. genetically discrete populations) and assessment of the composition of feeding and harvested populations.