bluuebunny/crossref_metadata_2025_split huggingface dataset:
The population age structure and reproductive biology of Gyrodactylus salaris Malmberg (Monogenea)
Authors: Harris P. D. , Jansen P. A. , Bakke T. A. 
Published: June 2009

SUMMARYGyrodactylus salaris has recently become a major pathogen of Atlantic Salmon (Salmo salar) in Norway. The survivorship, population age structure and pattern of insemination of G. salaris were studied to determine the extent to which this species reproduces sexually. The age-specific mortality schedule of G. salaris could be described by an exponential model but day to day variations were large, with an increase in mortality after each birth. Modelling population growth using the best fit mortality schedule indicated that, at stable age structure, 35% of the population would consist of newborn and pre-1st birth flukes. Using testis, penis and embryo development, pre-1st birth and immediately post-1st birth flukes could be unambiguously identified, and established infections were found to contain 35% pre-1st birth flukes, as predicted. The proportion of pre-1st birth flukes in newly established infections was significantly smaller, probably because of differences in the rate of transmission between newborn and older flukes. Gyrodactylus salaris is relatively long-lived, and more than 40% of the population may survive to give birth for the third time. As gyrodactylids are protogynous, and the first daughter is probably produced asexually, this long-lived strategy ensures that a large part of the G. salaris population possesses a functional male system, and that the asexually derived flukes are a smaller component of the total population in this species. Flukes with whorls of inseminated spermatozoa within the seminal receptacle were found in all age groups possessing a functional male system, and were interpreted as having been cross-inseminated. G. salaris on susceptible Norwegian salmon appears to regularly reproduce sexually, possibly accounting for its morphological variability and wide range of potential salmonid hosts.
The relationship between worm population density, host survival and the growth of the third-stage larva of Amplicaecum robertsi Sprent & Mines, 1960, in the mouse
Authors: Dobson Colin 
Published: June 2009

Female mice survived longer than male mice when infected with 400 eggs but not when infected with 100 eggs of Amplicaecum robertsi.The larvae grew to greater lengths in young than in older mice; smaller worm burdens were also found in the older animals.The growth of the larva was associated with the total worm burden of the host. As the worm burdens, of 40-day-old female mice, increased up to 281 individuals the length of the larvae attained after 14 days decreased; when the larval population increased above this number the lengths of the worms also increased.These crowding effects are discussed in relation to competition for nutrients, immunological suppression of larval growth and to the ability of large larval populations to swamp the resistance mechanisms of the host. It is suggested that the increased growth of the larvae in large populations is due to their ability to break down the liver of the infected host more efficiently than small populations. However, this eventually leads to the deaths of the host through total liver breakdown.This work was done during the tenure of a Senior Research Fellowship from the Wool Research Board of Australia. My best thanks are due to Mr J. James for his assistance with the statistics, to Professor J. F. A. Sprent for his help and advice and to Mr C. Wilkinson for his assistance.
Certain aspects of the host-parasite relationship of Nematospiroides dubius (Baylis)
Authors: Dobson Colin 
Published: June 2009

Adults of Nematospiroides dubius recovered from female mice were smaller than those from male mice. In general, a similar result was obtained for infections in rats. Longer worms were recovered from gonadectomized rats than from intact animals; the difference between the growth of the worms in male and female hosts was still apparent.Treatment of castrate male rats with testosterone was more favourable to the growth of the male than the female worm. Oestradiol treatment of spayed female rats caused a stunting of both sexes of the nematode. However, this effect was least noticeable among the female worms.An increase in the age of the rat resulted in a decrease in the lengths of the worms recovered. The worms grew to greater lengths in 25-day-old mice than in rats of the same age and sex.It is suggested that the sex hormones may have two effects on worm growth. First, an indirect effect involving the nutrition of the worm, and secondly, a direct effect of the hormones themselves on the tissues of the worm.This work was done during the tenure of a Department of Scientific and Industrial Research Studentship. My thanks are due to Dr E. T. B. Francis for his help and criticism, and to Professor I. Chester Jones, in whose department the work was done, for the facilities he provided.
The effects of pregnancy and treatment with progesterone on the host–parasite relationship of Amplicaecum robertsi Sprent & Mines, 1960, in the mouse
Authors: Dobson Colin 
Published: June 2009

Male mice harboured more third-stage larvae of Amplicaecum robertsi than females; these larvae also grew longer than did those in female mice. Gonadectomy removed the differences, evident between the sexes, in both the numbers recovered and the growth of the third-stage larva, between male and female mice. The worms recovered from the gonadectomized hosts were smaller than those from the intact male and female host.Pregnant female mice harboured more worms than either the male or the non-pregnant female mouse. These worms were also smaller than those from the male and non-pregnant females. There was no difference in the growth of the larvae from gonadectomized and pregnant hosts.The treatment of spayed female mice with progesterone resulted in an increase in the size of worm population as compared with the numbers of worms recovered from intact female mice. The worms from the progesterone-treated spayed females were also longer than those from the spayed female hosts.Treatment of normal female mice with progesterone resulted in an increased recovery of worms compared with the numbers of worms recovered from normal female animals. The worms were stunted but they were of a size comparable to those recovered from pregnant female mice.It is suggested that the increase in the size of worm populations and the stunting of the worms recovered from pregnant female mice is associated with the effects of progesterone in relation to the hormone balance associated with the ovary at the time of pregnancy.
The attachment of the monogeneanDiplectanum aequans(Wagener) Diesing to the gills ofMorone labraxL.
Authors: Paling J. E. 
Published: June 2009

The main adhesive apparatus ofDiplectanum aequansis described and a functional interpretation is offered.Two sets of organs are involved in adult animals: 4 hamuli (median hooks) and the 3 associated accessory bars, and 2 squamodiscs.The two pairs of hamuli are ‘gaffed’ into the gill tissue of the host by the following mechanism: muscular contraction produces a posterior movement of the anterior ends of the hamuli which are so pivoted that the points of the hamuli are caused to extend out from the haptor.The squamodiscs of adults are operated by extrinsic muscles which produce posterior movement in the anterior region of each squamodisc. This tends to push the parasite out from its position between adjacent secondary gill lamellae.The tendency to dislodgement is opposed by the two pairs of hamuli which ‘gaff’ into the base of the secondary lamellae. In addition, the more posterior spines on the squamodiscs become embedded in the gill tissue and so provide further resistance to the movement of the anterior region of the squamodisc. Thus the attachment of adults requires both sets of adhesive organs functioning in a complementary manner.Juveniles do not possess squamodiscs. They are considered to adhere to their hosts primarily with their hamuli.I would like to acknowledge the help given to me by the Director and Staff of the Marine Biological Association Laboratory and also the Proprietors of Cook and Sons Ltd., of Salcombe, Devon.
Fasciola tragelaphisp.nov. from the sitatunga,Tragelaphus spekeiRothschild, with a note on the prepharyngeal pouch in the genusFasciolaL.
Authors: Pike A. W. , Condy J. B. 
Published: June 2009

Fasciola tragelaphisp.nov. from the bile ducts of aTragelaphus spekeishot in the Chobe swamps of Rhodesia differs from other species of the genus in its very large size (10.2–12.0 cm long in fixed and mounted specimens), in the shape of its body and in the distribution and arrangement of the reproductive organs. The testes lie almost entirely in the posterior half of the body, well away from the female genitalia, which lie mostly in the anterior third of the worm. The ovary is always bilateral, and the coiled uterus runs in a straight line between the caeca to the genital atrium. A prepharyngeal pouch found in this species is compared with that found in other members of the genusFasciolaand in related genera.We gratefully acknowledge the help given during the preparation of this paper by the staff of the Bureau, particularly Mr G. Dimmock for technical assistance. We would also like to thank Mr S. Prudhoe for reading the manuscript and offering useful advice, Mr B. Bracegirdle for producing the photograph of the whole worm reproduced in the Plate, fig. 1 and to Bechuanaland Hunters Ltd., particularly I. M. Henderson, for obtaining further specimens for examination.
Oviposition in Hyalomma anatolicum anatolicum (Koch, 1844) (Ixodoidea: Ixodidae)
Authors: Snow K. R. , Arthur Don. R. 
Published: June 2009

For the tick Hyalomma anatolicum anatolicum, at constant temperature and humidity, the pattern of oviposition is constant, and consists of a peak period, usually after 2–3 days, followed by a gradual decline.Oviposition proceeds more rapidly in constant darkness than in continuous light.With increased temperature the oviposition period is decreased, but with increased humidity the period is extended.The largest eggs are laid from 0 to 48 h after the peak of egg production, and no correlation has been observed between female size and egg size.The number of eggs produced by a tick is directly proportional to its engorged weight, and since the engorged female weight is a direct reflexion of its unfed weight, the number of eggs laid is directly dependent on the size of the unfed female.Guinea-pigs show partial immune response to adults of H. anatolicum anatolicum when the ticks are fed on them repeatedly. This minimizes the amount of nutrients imbibed and accordingly egg-laying potential is not realized.The material on which this study was made was presented to us by Dr R. P. Chaudhuri, and we gratefully acknowledge his kindness.
Histochemical demonstration of aminopeptidase activity associated with the intramolluscan stages ofPhilophthalmus gralliMathis & Léger
Authors: Cheng Thomas C. , Yee Herbert W. F. 
Published: June 2009

Third-generation rediae and escaped cercariae ofPhilophthalmus gralliare found primarily in the interacinar spaces on the periphery of the hepatopancreas of its molluscan host,Tarebia granifera. The presence of these stages ofP. grallicauses both mechanical and physiological damage to the adjacent host cells. Mechanical damage results from ingestion by rediae and pressure exerted by motile rediae and cercariae. Histochemical tests involving two different substrates L-leucyl-α-naphthylamide and L-leucyl-4-methoxy-β-naphthylamide, have revealed the occurrence of aminopeptidase activity associated with the body surfaces of both rediae and cercariae. This exopeptidase is believed to be responsible for the lysis of the cytoplasm of surrounding host cells during migration and to be associated with extracaecal digestion. The intensity of the enzyme activity is correlated with the ages of the rediae and cercariae. Young rediae did not reveal aminopeptidase activity and cercariae within redial brood chambers revealed little or no activity.This research was supported in part by a grant from the American Cancer Society.
A gigantic Protostrongylus, P. africanus sp.nov., and other lung nematodes of antelopes in the Serengeti, Tanzania
Authors: Dinnik J. A. , Sachs R. 
Published: June 2009

It was found that antelopes in the Serengeti area, Tanzania, East Africa, are heavily infested with lung nematodes. Five species of the family Protostrongylidae, namely, Protostrongylus africanus sp.nov., P. etoshai Ortlepp, P. gazellae Yeh, Pneumostrongylus calcaratus Mönnig and P. cornigerus Ortlepp, as well as one species of the family Dictyocaulidae, Dictycaulus viviparus (Bloch), were recorded.A detailed description of Protostrongylus africanus sp.nov., which is conspicuous for its gigantic size, is given, and the lesions caused by this lung nematode are described.The distribution and incidence of lung nematodes in the various antelope species are discussed.
Chromosomes of the tsetse fly, Glossina palpalis R.-D.
Authors: Riordan K. 
Published: June 2009

Mitotic metaphase chromosomes of the tsetse fly Glossina palpalis R.-D. have been investigated.The chromosomes studied were in circumoesophageal nervous tissue from young pupae, stained with aceto-orcein and spread by squashing.The diploid number of chromosomes was shown to be 6, consisting of 2 long pairs and 1 short pair at metaphase.This finding is discussed briefly in relation to previous descriptions of the chromosomes of G. tachinoides West. and G. morsitans morsitans West. and to accepted systematic divisions of the genus Glossina into subgeneric groups.I wish to thank Mr H. Dickson for assistance with photography. I thank Mr D. A. T. Baldry for advice and suggestions concerning the manuscript. Mr T. M. Leach has also made suggestions concerning the manuscript, and as Director of the Nigerian Institute for Trypanosomiasis Research, has given his permission to publish this paper.
Serological and morphological studies on the inter- and intraspecific differences of the plant-parasitic nematodes Heterodera and Ditylenchus
Authors: Webster J. M. , Hooper D. J. 
Published: June 2009

Saline extracts of species of Ditylenchus and Heterodera initiated antibody production when inoculated separately into rabbits. On agar gel-diffusion plates these antisera gave a precipitate response against their homologous extracts and against extracts of some of the other nematode species. Up to four precipitation bands occurred, indicating the presence of at least four distinct antigens. Antisera to these extracts did not precipitate against extracts of the host plant or against the extracts of nematodes from other genera. None of the nematode extracts precipitated against normal serum. The precipitation response divided the Heterodera species tested into two groups, one containing H. schachtii, H. trifolii and H. rostochiensis and the other containing H. cruciferae, H. carotae and H. goettingiana with apparently no antigens common to both groups. The three species of Ditylenchus were serologically distinct, and it was not possible to interbreed D. myceliophagus and D. destructor. The extent of the postvulval sac was the most useful morphological character for separating D. myceliophagus from D. destructor. Only slight intraspecific serological differences were detected between five races (narcissus, oat, red clover, tulip and giant) of D. dipsaci and between the two pathotype populations (Colyton and Woburn) of H. rostochiensis. Precipitates occurred at the excretory pore of living larvae and adults of Ditylenchus species and at the vulval aperture of white females of Heterodera species placed in their homologous antisera.We thank Dr A. J. Gibbs for much advice.
Ixodes pacificusCooley and Kohls, 1943: Its life-history and occurrence
Authors: Arthur Don. R. , Snow Keith R. 
Published: June 2009

The life-history ofI. pacificuswhen fed on guinea-pigs under laboratory conditions is described. Feeding of the female proceeds for 10–11 days. Between 120 and 191 mg of concentrated food is found in the female's gut on detaching from this host, and this is directly related to the unfed body weight of the tick.The egg-laying pattern, in general, shows an initial peak, after which the number of eggs tails off, the whole process lasting approximately 33–40 days. The number of eggs laid by females varies between 790 and 1300. The preoviposition period is about 11–16 days.Larvae hatch in about 53–55 days, and their feeding time ranges from 4 to 9 days, although in the present experiments larvae emerging from early laid eggs took about 10 days to complete engorgements.Moulting of larvae to nymphs at 90% R.H. took 37–38 days, and nymphs fed for 7–11 days, with most becoming replete on the ninth.Very few females emerged from these nymphs, and those that did emerged in just over 30 days. The reasons for this are not clear. No diapause appeared to be necessary to complete the life-cycle, and with due allowance for hardening of the mouthparts the life-history of one generation was about 7 months. Females died within 3 or 4 months if hosts were not available.From the literature and from hitherto unpublished records some 55 vertebrates have been implicated as hosts toI. pacificus;these hosts include a wide range of mammals, six species of birds and possibly nine species of lizards.The species has been listed from British Columbia and from five western states of U.S.A. The need for more intensive ecological work on this species is emphasized.We are indebted to Glen M. Kohls, J. D. Gregson and D. E. Johnstone for permission to use unpublished records from their respective institutions. One of us (D.R.A) is also indebted to the Wellcome Trustees for financial assistance to visit Canada during the preliminary stages of the work.
Ultrastructural studies on the sporozoite of Eimeria tenella
Authors: Ryley John F. 
Published: June 2009

The structure of the sporozoite of Eimeria tenella has been studied with the aid of the electron microscope, using both sectioned fixed material and negatively stained or shadowed whole cells. An apical ring gives rise to a series of 24 fibrils which extend posteriorly under a double bilamellar membrane. Within the apical ring lies a conoid with spirally arranged tubules and an apical pore; under some conditions at least this conoid can be pushed forward beyond the apical ring. Originating within the conoid are a group of club-shaped organelles which extend backwards into the cell to lie among an extensive regular array of micronemes. The nucleus lies between two apparently structureless paranuclear bodies, and scattered throughout the remaining cytoplasm are mitochondria with tubular cristae, oval structures containing amylopectin, occasional lipid droplets, and vesicles containing nondescript material possibly undergoing digestion and which may have a possible connexion with a lateral micropyle.I am indebted to Mrs Muriel Bentley for much technical collaboration and to Mrs McLaren for making her manuscript available before publication.
Studies of the amino acids ofRhodnius prolixus. II. Analysis of the excretory material
Authors: Harington J. S. 
Published: June 2009

1. A qualitative paper chromatographic analysis of the free amino acids inRhodniusurine and excreta was made: eleven amino acids or related compounds were detected, cystine and cysteic acid in urine, and histidine, histamine, leucine, taurine, glycine, valine, phenylalanine and alanine in the excretory fractions.2. In addition to these, three yellow pigment spots were separated from the excreta; one of these is of unknown composition and two are peptides.3. A possible relationship between certain of the excretory amino acids and haemolymph ones is discussed.I am greatly indebted to the late Professor P. A. Buxton, C.M.G., F.R.S., for his stimulating criticism during this study, and to the members of the School for very useful discussion, and to Mr Paul Baily for performing the column chromatographic analyses on my behalf. The study forms part of a Thesis for the degree of Ph.D. approved by the University of London, and was financed by the South African Council for Scientific and Industrial Research. I wish to acknowledge their generous financial support.
The effect of the miteMyocoptes musculinus(C. L. Koch 1840) on the skin of the white laboratory mouse and its control
Authors: Watson D. P. 
Published: June 2009

1. The means of attachment of the miteMyocoptes musculinusto the hair of the host, the mouse, and the sites where it is located are given.2. Normal and skin infected withM. musculinusof young (6–8 weeks) and adult (6 months) mice is treated with colchicine and examined histologically.3. Infected skin shows a mitotic count of approximately four times that of normal skin in the adult; there is no appreciable difference in the young.4. Acaricides used to control the mite were benzene hexachloride (0·015%), dieldrin (0·015%), arsenic and sulphur mixture (0·018% arsenic), piperonyl butoxide (5%) and dimethylphthalate (100%); the latter being the most efficacious.5. It is established that the drugs had no effect on the rate of division of the cells of the malpighian layer of the skin.6. The number ofMyobiapresent increases as theMyocoptesare killed unless dimethylphthalate, an oily liquid, is used at intervals.7. Diet in conjunction with signs of mange is discussed.8. Carriers ofM. musculinusare given.I wish to thank Cooper McDougall for supplying the materials used in dipping and swabbing, and the Infestation Control Laboratory of the Ministry of Agriculture for supplying me with a number of specimens of wild mice from different parts of the country. I am also grateful to the Council of the Royal Free Hospital School of Medicine for facilities for carrying out the work; and to Dr A. M. Hughes for her helpful guidance at all stages of the work and especially for reading the paper.
Physiological studies on trematodes: the osmotic activity ofGastrothylax crumenifer
Authors: Goil Madan M. 
Published: June 2009

The percentage change in weight, at 38·2 °C, in different concentrations of sodium chloride at different intervals, of a trematode,Gastrothylax crumenifer, from the reticulum of buffaloes has been recorded.A state of approximate isotonicity is reached between 0·4 and 0·5% sodium chloride.The osmotic pressure has also been expressed in terms of freezing-point depression.
A new species of Toxascaris from hyenas
Authors: Warren E. G. 
Published: June 2009

Toxascaris versterae sp.nov. from hyenas in South Africa is described. T. versterae is compared with Toxascaris leonina, the only other member of the genus.I thank Professor J. F. A. Sprent for his advice and criticism. This work was supported by grants from the Australian Research Grants Committee and from the U.S. Department of Health, Education and Welfare, No. AI-07023–03.
Immunity of rats and mice following injection with60Co irradiatedBabesia rodhainiinfected red cells
Authors: Phillips R. S. 
Published: June 2009

Babesia rodhainiinfected mouse and rat red cells were non-infective after receiving 40 or 60 krad irradiation from a60Co source.Rats inoculated with irradiated infected red cells were subsequently found to show strong resistance to homologous challenge.Mice, which are more susceptible toB. rodhaini, showed less resistance to challenge, following immunization with irradiatedB. rodhainiinfected red cells.Splenectomized rats were immunized with irradiated infected blood. There was a delay compared with the controls in the onset of acute fatal parasitaemias in these rats. A population of parasites was isolated by taking and mixing blood from each of the splenectomized rats during the patent parasitaemia following challenge. This population appeared to be an antigenic variant of the original immunizing population.I thank Mrs J. Page for excellent technical assistance and Dr K. N. Brown for criticizing the manuscript.