The species Phytomonas serpens is known to express some molecules displaying similarity to those described in trypanosomatids pathogenic to humans, such as peptidases from Trypanosoma cruzi (cruzipain) and Leishmania spp. (gp63). In this work, a population of P. serpens resistant to the calpain inhibitor MDL28170 at 70 µm (MDLR population) was selected by culturing promastigotes in increasing concentrations of the drug. The only relevant ultrastructural difference between wild-type (WT) and MDLR promastigotes was the presence of microvesicles within the flagellar pocket of the latter. MDLR population also showed an increased reactivity to anti-cruzipain antibody as well as a higher papain-like proteolytic activity, while the expression of calpain-like molecules cross-reactive to anti-Dm-calpain (from Drosophila melanogaster) antibody and calcium-dependent cysteine peptidase activity were decreased. Gp63-like molecules also presented a diminished expression in MDLR population, which is probably correlated to the reduction in the parasite adhesion to the salivary glands of the insect vector Oncopeltus fasciatus. A lower accumulation of Rhodamine 123 was detected in MDLR cells when compared with the WT population, a phenotype that was reversed when MDLR cells were treated with cyclosporin A and verapamil. Collectively, our results may help in the understanding of the roles of calpain inhibitors in trypanosomatids.

1. Worms which had been cultured in media of different osmotic pressures were immersed in concentrated solutions of NaCl, KC1, CaCl2 and MgCl2, and the times of cessation of spontaneous movement noted.

2. Worms from ‘normal’ cultures were immersed in a single concentration of each of the above solutions (all osmotically equivalent to 0·51 M NaCl) and the shrinkage curves were determined.

3. Worms from ‘normal’ cultures were placed in NaCN and KCN solutions and the subsequent shrinkage on immersion in a concentrated balanced salt solution was measured. From these results it is concluded that cyanide decreases the permeability of the body to water, and also that NaCN enters the body more rapidly than KCN.

4. It has been shown that the chloride solutions which produce the greatest effect on the movement of the worms produce the least shrinkage and vice versa. From this it is concluded that the substances investigated can be arranged in order of their rates of penetration approximately as follows: NaCl> CaCl2> MgCl2, KCl.

5. It is suggested that the results obtained are more easily explained on the assumption that the rates of penetration of the substances used are controlled by the activities of living protoplasm than by the properties of non-living cuticle.

Evidence is presented of a periodicity of oogenesis and spermatogenesis in D. aegira. Pauses in oogenesis were detected between successions of oogonial divisions; in spermatogenesis, the intervals appeared to be longer and the pauses came before division of primary spermatocytes. Regulation of division rates was such that between two and three times as many spermatozoa as oocytes were produced.

Observations indicated that spermatozoa emerged from the axial cell soon after their formation and made contact with oocytes early, often before these were fully grown. Properties of the oocyte cell membrane evidently precluded precocious sperm entry and the penetration of more than one spermatozoon.

Sincere thanks are due to Dr R. B. Short, who kindly made available all the material, and to Dr S. W. Fox and Dr C. B. Metz for the excellent facilities provided. This work was supported by P. H. S. Research Grant E 4749 (Institute of Allergy and Infectious Diseases) awarded to R. B. Short, and by N.A.S.A. Grant NsG–173–62 and N.S.F. Grant G–9150. Contribution No. 019 of the Institute for Space Biosciences.

The consensus view of biomembrane structure is outlined. The present model is built upon a fluid lipid matrix, usually two molecules in length, into which the proteins are embedded. The lipid bilayer organization is discussed, such as their phase transition and fluid character and the effect of cholesterol upon the chain organization. The non-lamellar arrangement which some lipids adopt is described. The use of new physical techniques for obtaining information about the structure and dynamics of membrane proteins are described. These techniques include electron diffraction, electron microscopy and FTIR spectroscopy. Models of the structures of the Ca2+–ATPase and the glucose transporter from erythrocytes are shown, indicating the putative helices embedded in the lipid bilayer and the groups of amino acids in the aqueous environment. These models are based upon biochemical methods to obtain amino acid sequences using DNA cloning techniques. Finally, an experimental method using triplet probes is described for the study of the rotational dynamics of membrane proteins. Labelled monoclonal antibodies for studying the dynamics of the glucose transporter have been used.

The following case of Intestinal Myiasis occurred in a boy about twelve years of age, in normal health, who brought to me in September 1909 what he took to be “worms” discharged with his faeces. He said he did not feel anything abnormal but saw a mass of the creatures upon and in his freshly-voided faeces. He called his mother, and she stated to me afterwards that the “worms were in a cluster like a swarm of bees,” they were crawling about the faecal mass which was loose in character, as had been the case for several days. They varied considerably in size, as did the specimens brought to me. The mass of creatures would have filled one or two tablespoons.

A piroplasm was isolated from a wild-caught Psammomys obesus from the lower Jordan Valley. In wild-caught Psammomys the infection is submicroscopic or of very low intensity, but rises sharply following splenectomy. The animal from which the piroplasm was isolated died with a 44 % parasitaemia and haemoglobinuria, following splenectomy.

The piroplasm was transmissible to clean, laboratory-bred Psammomys, to hamsters and Meriones. It was not transmissible to, or gave rise only to transient infections in, adult mice, rats, Mastomys, Acomys and Arvicanthis. Suckling mice and rats showed low parasitaemias for a few days, although division forms of the parasite were observed.

No protective cross-immunity with Nuttallia danii was observed.

On the basis of its measurements, spectrum of infectivity to experimental animals and absence of cross-immunity with N. danii, the piroplasm of Psammomys is considered to be a new species.

The name Nuttallia meri, sp.nov. in memory of the late Prof. Gr. G. Mer, is proposed for this piroplasm of Psammomys obesus.

I should like to express my appreciation of the excellent technical assistance provided by Mrs Miriam Sarfatti and Mr A. Bortinger, and to thank Dr Y. Schlein for his help with some of the drawings. I am particularly indebted to Dr A. Hadani of the Kimron Veterinary Institute for providing me with Meriones and testing N. meri in his laboratory.

This study was supported by the Reubin Kunin and Samuel Lunenfeld Medical Research Foundation - to which grateful acknowledgement is made.

Aragão (1912) has recently described a new species of tick which he raised through three complete generations upon cold-blooded animals, the natural hosts in Brazil. He gave the species the name Amblyomma agamum because reproduction occurred parthenogenetically, males not having as yet been observed. The tick, in common with most other Ixodidae, feeds upon three successive hosts in the larval, nymphal and adult stages; it may, however, undergo metamorphosis from larva to nymph upon the host. This observation of Aragão's is the first of the kind, for parthenogenesis has not hitherto been observed in ticks. In the course of his raising experiments he obtained thousands of females which laid fertile eggs in the absence of males.

An anthelmintic test was carried out in lambs against fourth-stage larvae of Haemonchus contortus to determine whether a natural loss of worms from either untreated control animals or from animals treated with anthelmintic affected the estimated activity of the anthelmintic.

Thirty-two lambs were each infected with 1500 larvae of H. contortus on 4 consecutive days and divided into 4 groups of 8 animals. Two groups of lambs were treated with anthelmintic on day 7, the first group being slaughtered on day 9 and the second on day 29. An untreated control group was slaughtered 7 days after infection and a second control group was killed 29 days after infection.

The numbers of worms recovered indicated that in the untreated control lambs there was an estimated daily loss of about 7% of the parasite population between the first day of infection and day 29, and in the lambs given anthelmintic an estimated daily loss of about 2% of the worm population was indicated between days 9 and 29. If the rate of worm loss is not the same in the untreated control hosts and in the treated animals, the estimate of anthelmintic efficacy will vary according to the time of autopsy. To minimize the possibility of an incorrect result occurring in an anthelmintic trial due to a natural loss of worms, it is recommended that the untreated control and the treated lambs are slaughtered on the same day, and that the autopsy is carried out as soon as possible after anthelmintic therapy.

Two new species of the genus Hoplopleura are described from two closely related species of the genus Mus. H. ramgarh sp.nov. was found parasitizing Mus platythrix Bennett, 1932, in the Western Himalayan region in North India and in the Western Ghats in Peninsular India. H. sinhgarh sp.nov. was found parasitizing a species of the genus Mus, closely related to M. platythrix, and occurring sympatrically with it. The exact taxonomical status of this rodent species is still under investigation. The occurrence of two distinct species of lice on closely related sympatric populations of these mice has given an indication of their being two distinct taxa, a fact later supplemented by some consistent but not easily delineable skin and skull characters.

The survival of fasting imagines of Hyalomma savignyi under various conditions of temperature and relative humidity was studied.

Within the range of experimental conditions low temperature and high humidity are shown to be most favourable to the survival of ticks: at 17·5° C. and 80–95% R.H. mean longevity approaches 1 year, and a few individuals were observed to survive for more than 2 years. Longevity shortens as temperature rises and relative humidity decreases. At a temperature of 37° C. (and under various conditions of humidity) average longevity does not exceed 1·5–3·5 months, while under conditions of extreme dryness, viz. 10–20% b.h. (and various temperatures) average longevity ranges from 1·5 to 9 months.

The longevity of fasting imagines is not as much affected by dryness as that of preimaginal stages.

Through the kindness of Mr Nelson Annandale, Director of the Indian Museum, I have recently had the opportunity of examining a small collection of Pentastomids from that Museum. The collection contains one new species of Porocephalus and affords examples of new hosts and new localities in which species already known have been found. In all there were four different species.

Recently the writer has had occasion to go over and help arrange the United States National Museum collection of fleas. Although not as extensive as some of the other well-known flea collections, it is invaluable of the Philippines, and of Doctor Carrol Fox, Surgeon, United States Philippines, and of Doctor Carrol Fox, Surgeon, United States Public Health Service, Two of the foremost authorities on the Siphonaptera.

Two strains of Eimeria tenella with different decoquinate sensitivity and different glucose phosphate isomerase (GPI) isozymes were used in genetic recombination experiments: a line derived from a laboratory strain (NIAH) was decoquinate-resistant (DR) and had the isozyme GPI-9, while a field isolate (Iwate strain) was decoquinate-sensitive (DS) and had GPI-1. Coccidia-free chickens were orally inoculated with mixed oocysts of the two strains and parasites of the F1 generation were recovered. The F1 progeny showed both forms of the isozyme. Next, oocysts of the F1 progeny were passaged through chickens given the decoquinate-containing diet. The F2 progeny also had GPI-1 and GPI-9, indicating crossfertilization between the two strains. Six single oocysts were isolated from F2 progeny; 1 showed both phenotypes of GPI, 1 had GPI-1 and the remaining 4 lines had GPI-9. Analysis of the amount of GPI in recombinant oocysts suggested that the proliferation rate of the DR strain was slower than that of the DS strain. We concluded that GPI isozymes in E. tenella can serve as useful markers in experiments on chicken coccidia.

On 6 November 1939, shortly after the invasion of Poland, the professors at the Jagellonian University of Cracow were summoned to attend a lecture on “Nazi Science”, to be delivered by a high German official. Those who obeyed the order were arrested. The charge brought against them was, in brief, that they had been attempting to fulfil their duties at the University, and were thereby guilty of striving to keep alight the flame of Polish national culture. For these offences the unfortunate professors—some of them old and feeble— were imprisoned and robbed of their property. After being jailed in Cracow they were taken to a convict prison at Breslau and thence to a concentration camp at Sachsenhausen-Oranienburg (near Berlin)—where, of course, many of them died.

Virgin females of Brugia malayi, B. pahangi and B. patei were mated with males of species other than their own to determine whether they would hybridize. Microfilariae were produced in all but one cross (that between B. pahangi males and B. malayi females). Hybrid infective larvae, produced in mosquitoes and inoculated intraperitoneally into jirds, grew to adults but these were unable to produce microfilariae because hybrid males did not produce spermatozoa. Hybrid females were fertile and produced microfilariae when crossed with males of their parental species.

We address the question of whether host and/or environmental factors might affect endoparasite richness and distribution, using carnivores as a model. We reviewed studies published in international peer-reviewed journals (34 areas in the Iberian Peninsula), describing parasite prevalence and richness in carnivores, and collected information on site location, host bio-ecology, climate and detected taxa (Helminths, Protozoa and Mycobacterium spp.). Three hypotheses were tested (i) host based, (ii) environmentally based, and (iii) hybrid (combination of environmental and host). Multicollinearity reduced candidate variable number for modelling to 5: host weight, phylogenetic independent contrasts (host weight), mean annual temperature, host trophic level and biogeographical region. General Linear Mixed Modelling was used and the best model was a hybrid model that included biogeographical region and host trophic level. Results revealed that endoparasite richness is higher in Mediterranean areas, especially for the top predators. We suggest that the detected parasites may benefit from mild environmental conditions that occur in southern regions. Top predators have larger home ranges and are likely to be subjected to cascading effects throughout the food web, resulting in more infestation opportunities and potentially higher endoparasite richness. This study suggests that richness may be more affected by historical and regional processes (including climate) than by host ecological processes.

Cell extracts of an entero-invasive protozoon of squirrel monkeys, Tritrichomonas mobilensis, contained relatively high proteolytic activity, measured on hide powder azure (HPA). Multiple proteinase forms, optimally active at pH 5–7, were detected by electrophoretic analysis in gelatin-containing polyacrylamide gels. Three major proteinase bands of apparent low molecular weights, Mr 18, 23 and 30 kDa, were seen on gels. Inhibition-activation studies suggest that only cysteine proteinases were involved in HPAase and gelatinolytic activities of T. mobilensis cell extracts.

Apicomplexan parasites cause devastating diseases in humans and livestock. Previously we demonstrated that antibodies targeting transmissible forms of the apicomplexan parasite, Eimeria, are effective at reducing parasite shedding thus preventing the transmission of the disease. However, the mechanisms responsible have not been fully defined. Moreover, there is no direct evidence that the parasite-specific IgG antibodies can reach the parasite developing in the enterocytes of the infected chicken host. This study summarizes our efforts using host immunity, parasite proteomics and 3D microscopy to provide a step forward in our understanding of how this immune response works. Eimeria maxima is an important pathogen of poultry and used as a surrogate for a number of human pathogens including Toxoplasma and Plasmodium. Our studies demonstrate that immunization with the purified wall forming bodies (WFBs) results in a production of parasite-specific IgG antibodies, which have the ability to reach in situ gametocytes in the intestinal lumen and permeate the enterocyte/parasite membranes in order to bind to the cytoplasmic Type 1 and Type 2 WFBs. This raises the intriguing possibility that via this process antibodies block the development of Eimeria maxima in vivo.

The material upon which this paper is based was secured in May, 1930, from a specimen of Scopus umbretta bannermani C. H. B. Grant (Ciconiiformes) which had been shot by a native on the Buzi River in Mozambique, about 40 miles from the eastern border of the Melsetter District of Southern Rhodesia. Several hours elapsed before the bird was brought into camp and its skin prepared for museum purposes, and our parasitological examination of the specimen was carried out under some difficulty with failing light. No worms were found in the alimentary tract, but on removing the liver and teasing this organ apart about twenty trematodes were recovered. To the naked eye these appeared very similar to schistosomes and, accepting this as a tentative diagnosis, we assumed that the parasites had been loosened from an abode in the branches of the hepatic portal vein. Considerably later, when we sought to identify the formalin-preserved specimens, it became evident that we had chanced upon an infection with a species of “holostome” closely related if not identical with that atypical and obscurely known form, Holostomum serpens.