bluuebunny/crossref_metadata_2025_split huggingface dataset:
The ultrastructure of the tegument of adult Schistosoma haematobium
Authors: Leitch B. , Probert A. J. , Runham N. W. 
Published: June 2009

SummaryThe ultrastructure of the tegument of Schistosoma haematobium was examined using scanning and transmission electron microscopy. The surface of the male worm is characterized by numerous raised tubercles bearing apically directed spines. The female in contrast to the male is cylindrical and relatively smooth. Details of oral and ventral suckers are given. The use of uranyl acetate as a tertiary fixative and en bloc stain has revealed the heptalaminate nature of the outer membrane. Tegumental mitochondria are shown to be morphologically more complex than those of S. mansoni. Spherical and elliptical inclusion bodies are also described. The ultrastructure of the oesophageal tegument of S. haematobium is described for the first time and corresponds with earlier observations of S. mansoni.
The use of frequency distributions in an attempt to detect host mortality induced by infections of diplostomatid metacercariae
Authors: Kennedy C. R. 
Published: June 2009

SummaryFollowing recent suggestions that a peaked host age–parasite abundance curve, concomitant with a decline in the degree of dispersion of parasites in the older age classes of hosts, can provide evidence of parasite-induced host mortality, the changes in mean abundance and over-dispersion of metacercarial stages of Diplostomum spathaceum, D. gasterostei, Tylodelphys clavata and T. podicipina in relation to fish age were studied in a field locality. The mean parasite burden of D. spathaceum, D. gasterostei and T. clavata increased with host age and the maximum mean burden was found in the oldest hosts. The variance to mean ratio also increased in D. gasterostei, but decreased in the oldest hosts in D. spathaceum and T. clavata. It is concluded that this decrease could be due to parasite-induced host mortality but could equally be due to death of parasites within the host or to changes in infection rate or could be a reflection of the small sample size of the oldest fish. The mean burden of T. podicipina declined gradually with host age, but the variance to mean ratio remained constant and it is concluded that this could be explained by death of the parasites within the host. None of these data or data from other localities provided clear and unambiguous evidence of host mortality induced by heavy infections of any of the four species, although they are consistent with such mortality and do not refute such a possibility. It is concluded that it may be just as difficult to detect and unequivocally demonstrate parasite-induced host mortality in metacercarial digenean–fish host systems as in any other parasite–host systems.
Temperature-dependent reproduction and survival of Gyrodactylus bullatarudis (Monogenea) on guppies (Poecilia reticulata)
Authors: Scott Marilyn E. , Nokes D. J. 
Published: June 2009

SummaryTemperature-dependent survival and reproduction of Gyrodactylus bullatarudis Turnbull, 1956 were examined at 17, 21, 25·5, 27·5 and 30 °C on isolated guppies under conditions where parasite density dependence and host responses were minimized. Parasites had the longest life-span (5·5 days) at 21 °C, the highest average fecundity (1·73 offspring) at 25·5 °C and the highest instantaneous per capita birth rate (0·543/parasite/day) at 27·5 °C. The intrinsic rate of increase of the parasite population was maximum (0·230/parasite/day) at 27·5 °C. Data obtained from this study indicate that G. bullatarudis are not able to survive at 30 °C.
Immunization of rats againstSchistosoma mansoniusing irradiated cercariae, lung schistosomula and liver-stage worms
Authors: Ford M. J. , Bickle Q. D. , Taylor M. G. 
Published: June 2009

SummaryIn PVG rats a single immunizing infection withSchistosoma mansonicercariae exposed to 0, 5, 10 or 20 krad. gamma radiation failed to induce more than minimal resistance (17–29%) to challenge 4 weeks later, whereas 4 immunizations with 20 krad.-irradiated cercariae, over several months, induced substantial resistance (75%). In contrast, significant protection was induced in Fischer rats by a single immunization with unirradiated cercariae or cercariae irradiated with up to 80 krad. Comparable resistance was induced by unirradiated and by 2, 5 and 20 krad.-irradiated cercariae (67–74%) and lower levels by 10, 40 and 80 krad.-irradiated infections (57, 48 and 33%, respectively). Although the resistance induced by a single dose of 1000 20 krad.-irradiated cercariae could be boosted by a second (88%), further immunizations failed to enhance this resistance. Also, increasing the number of immunizing cercariae in single or multiple vaccinations from 1000 to 3000 failed to increase the resistance. While the resistance induced by 20 krad.-irradiated cercariae persisted undiminished for at least 25 weeks (67%), the resistance induced by normal cercariae declined to insignificant levels by 25 weeks (21%). Comparison of the migration and survival of unirradiated and of 20 and 40 krad.-irradiated cercariae revealed dramatic differences in their fate: parasites exposed to 40 krad. remained in the skin, while the majority of 20 krad.-irradiated parasites died in the lungs after a sojourn of at least 14 days. Thus, although skin schistosomula alone could induce significant protection, optimal resistance was induced only by parasites which migrated to the lungs or beyond. The immunizing potential of these older parasites was investigated by exposing rats to lung-and liver-stage larvae injected into the tail and mesenteric veins, respectively. Irradiated 4-day lung schistosomula induced comparable resistance (79%) to that induced by a complete unattenuated cercarial infection (78%), whereas less resistance was induced by irradiated and unirradiated 11-day-old liver worms (30 and 27%) and by 25-day-old pre-adult worms (48%).
Degeneration Phenomena of Trypanosoma gambiense
Authors: Hindle Edward 
Published: June 2009

After treatment with arsenophenylglycin the number of trypanosomes in an infected animal immediately begins to decrease, and the parasites disappear from the peripheral circulation 6—7 hours after the time of injection, the short stumpy forms being the last to degenerate.One of the first changes noticed in the trypanosomes after treatment is the rounding up of their posterior extremities caused by the retraction of the protoplasm behind the kineto-nucleus. Meanwhile the tropho-nucleus becomes filled with granules of volutinose, which are extruded into the cytoplasm and pass along the axial filament towards the anterior extremity of the body. In dividing forms the granules form two longitudinal rows, being distributed along the two axial filaments. Finally, the granules lose their regular arrangement and become scattered throughout the cytoplasm, being more abundant, however, at the anterior end.The kineto-vacuole, when present, enlarges considerably and may become filled with chromatic substance derived from the kineto-nucleus.The axial filament begins to degenerate soon after treatment, often breaking up into a row of granules. Occasionally, however, chromatic substance from the kineto-nucleus passes along the axial filament, and it then appears as a thick black band extending along the middle of the cell eventually to the anterior extremity. Subsequently it breaks up into granules which dissolve in the cytoplasm of the cell.Chromatic bodies are given off from the kineto-nucleus both before and after treatment and do not seem to be a characteristic feature of degeneration.Sometimes the tropho-nucleus completely disappears before the cytoplasm breaks up into fragments, but at other times it preserves its form long after all other parts of the trypanosome, with the exception of the flagellum, have disappeared. These free nuclei resemble the “latent bodies” described by Salvin-Moore and Breinl, but as they, along with the fragments of cytoplasm, granules etc., are ingested by the leucocytes, it seems possible that they are merely one of the results of degeneration and not part of the life-cycle of this parasite.These investigations have been carried on partly with the aid of a grant from the Tropical Diseases Research Fund (Colonial Office).
A Study of the Diverse Races of Entamoeba histolytica distinguishable from one another by the dimensions of their Cysts
Authors: Dobell Clifford , Jepps Margaret W. 
Published: June 2009

1. Entamoeba histolytica Schaudinn (vel E. dysenteriae Councilman and Lafleur), the human dysentery amoeba, is a collective species. It comprises a number of distinct races, strains, or pure lines, distinguishable from one another by the size of the cysts which they produce.2. How many such distinct races exist is still undetermined; but we have demonstrated the existence of at least five.3. There is no evidence that the different races differ in their geographical distribution, or in any character save size.4. These races remain constant in character within a given host; and the dimensions of the cysts are not determined by the action of the host upon the parasite, since two different races may coexist side by side in the same host.5. Different values for the dimensions of the cysts are obtained when these are measured in different media. Taking the measurements of living cysts suspended in physiological saline solution as representing the true value, we find that the dimensions of cysts in iodine solution are approximately the same; but that cysts which have been suitably fixed, stained, and mounted in balsam, have undergone an apparent reduction of approximately 10% from the true diameter.6. The most suitable fixative for E. histolytica cysts we have found to be a modification of Schaudinn's fluid. (Saturated aqueous solution of corrosive sublimate, two parts; absolute alcohol, one part; glacial acetic acid, 4–5%.) Cysts fixed in this fluid undergo no measurable shrinkage or swelling in the process.7. The apparent loss of size observed in cysts which have been fixed, stained, and mounted in balsam, is due chiefly to the invisibility of the cyst wall in the mounting medium.8. It follows from what has been said above (5 and 6) that to obtain an approximately true value for the dimensions of the living cysts from measurements made upon those suitably fixed, stained, and mounted in balsam, these measurements should be multiplied by the factor 9. We find no evidence of the existence of a sexual dimorphism in the cysts belonging to a single race, such as has been described by Mathis and Mercier.10. Since cysts of E. histolytica may be found with all diameters from about 5μ. to about 20μ—a range overlapping or covering the dimensions of the cysts of the two common harmless intestinal amoebae of man (E. coli and E. nana) and of other cysts and cyst-like bodies occurring in human faeces—it is of considerable practical importance to recognize and distinguish the diverse races of E. histolytica which differ from one another in the dimensions of the cysts which they produce.
Observations on Entamoeba histolytica
Authors: Cutler D. Ward 
Published: June 2009

1. Observations on E. histolytica from the human intestine have been made and compared with amoebae living in culture media and in the ulcers of the large intestines of cats, which have died of amoebic dysentery.2. The effects of the substances chlorine, tyrosin, and skatol on culture amoebae have been investigated; it has been found that the two first substances stimulate vegetative reproduction, but that skatol induces cyst formation.3. The changes that the nucleus undergoes preparatory to division and the behaviour of the karyosome during division are fully described. It is shown that the nuclei originally described as characteristic of E. histolytica and E. tetragena are phases of nuclear change in the life history of the same animal.4. Cyst formation and the nuclear divisions in the cysts are described, together with a short discussion as to the view taken that the chromatoid bodies are not comparable with the chromidia of other Rhizopoda.5. Reasons are adduced for the suggestion that during the further development of the cysts quadrinucleate amoebae emerge, which divide to form four small amoebulae.6. Degeneration in E. histolylica is described and the view of Darling, that budding phenomena are degenerative ones, is confirmed.
The Behaviour of Balantidium coli Malm. in Cultures
Authors: Jameson A. Pringle 
Published: June 2009

Balantidium coli (from the domestic pig) can be readily cultivated in the medium devised by Dobell and Laidlaw (1926) for the cultivation of entozoic amoebae (inspissated horse-serum and Ringer-eggwhite, with solid rice-starch). If the hydrogen-ion concentration does not exceed the limits p H = 5·4–8·0, rich cultures can be obtained in this medium, at 37° C.; and strains of the ciliate can be readily propagated for any desired period if subcultures are made every 3–5 days.In such cultures conjugation occurs periodically; but encystation has never been observed, and all attempts to induce it under cultural conditions have hitherto failed.The conjugation of Balantidium, as seen in cultures, is peculiar, but it has been impossible as yet to elucidate all details of the process. Conjugants are always much smaller than non-conjugants, and frequently unequal in size. Apparently but one conjugant is fertilised, and survives as an exconjugant—the partner dying after separation.Encystation has never been seen to follow conjugation, as described by Brumpt (1909).
Observations on some Parasites ofOscinella fritLinn
Authors: Imms A. D. 
Published: June 2009

The stem infestation ofOscinella fritin England is attacked by at least two species of hymenopterous parasites of considerable importance. The species areHalticoptera fuscicornisWalk. (Chalcidoidea) andRhoptromeris euceraHtg. (Cynipoidea). It is also parasitised to a much lesser degree byLoxotropa tritomaThoms. (Proctotrypoidea). These three species are described and figured in detail.The three species named above have been reared by the writer from host puparia obtained in the Harpenden district; they have also been reared in the Leeds and Oxford districts by other observers. They attack the host in the larval stage of the latter and emerge from the puparia. All three species are characteristic parasites of cyclorrhaphous Diptera.In the Harpenden district a parasitism of 27 per cent. was observed in 1926 and of 37 per cent. in 1927,Rhoptromeris eucerabeing the dominant parasite.Evidence is brought forward which appears to indicate that the parasites, collectively, become more abundant as the season advances, with the result thatOscinella fritaffecting late sown oats suffers markedly heavier parasitisation than when it attacks oats drilled earlier in the season.The time of maximum emergence ofOscinella fritin out-of-door rearing cages during the years 1926 and 1927 coincided very closely with its period of greatest abundance in the field, as recorded by Cunliffe.
Larval Flukes associated with the Cercariae of Clonorchis sinensis in Bithynoid Snails in China and Adjacent Territory
Authors: Faust Ernest Carroll 
Published: June 2009

1. Eleven new species of cercariae are described from China. Of this number ten have been obtained from species of bithynoid snails and one from Planorbis möllendorfi.2. One of these species, Cercaria beatifica, a heterophyid larva, needs to be differentiated from the cercaria of Clonorchis sinensis, which develops experimentally in the same mollusc.3. The forms described are much more common parasites of bithynoid snails than is the larva of Clonorchis.4. Wherever it has been possible the larval characters, particularly those of the excretory system, have been utilised to show the relationship of the cercariae to adult groups.
The anatomy of three digenetic trematodes, Skrjabiniella aculeatus (Odhner), Lecithochirium rufoviride (Rud.) and Sterrhurus fusiformis (Lühe) from Conger conger (Linn.)
Authors: Jones Dilys O. 
Published: June 2009

1. The anatomy of three digenetic trematodes from Conger conger (Linn.), Skrjabiniella aculeatus (Odhner), Lecithochirium rufoviride (Rud.) and Sterrhurus fusiformis (Luhe) has been described. The technique employed is given, and in each case the history of the species has been traced.2. The discussion on the nomenclature of Skrjabiniella aculeatus explains why this generic name used by Issaitschikow (1928) has been adopted in this work in place of Prosorhynchus, and a key to the genera Prosorhynchus s.str. and Skrjabiniella has been suggested. A table showing the proposed division of Odhner's genus Prosorhynchus is included.3. In the discussion on the hemiurid worms it is pointed out that there is no sound basis for the separation of the genera Lecithochirium and Sterrhurus as they stand.
Studies on the nature and properties of the perienteric fluid ofAscaris lumbricoides
Authors: Rogers W. P. 
Published: June 2009

1. The composition of the perienteric fluid ofAscaris lumbricoidesof the pig, immediately after removal from the host and after varying periods ofin vitrostarvation, is recorded.2. Apart from the more frequently observed constituents of invertebrate tissue fluids, the body fluid ofAscariswas found to contain ascorbic acid, amino sugar and small amounts of uronic acid.3. Large amounts of anion other than chloride, probably fatty acid, must have been present in the body fluid, though chloride was probably the predominant anion in fluids of parasites which had passed several days ofin vitrolife.4. The chief factors (starvation, osmotic pressure and the nature of the medium, etc.) affecting the composition of the body fluid are briefly discussed.
The early stages ofLimnophora exurdaPand. (Diptera, Anthomyidae)
Authors: Tate P. 
Published: June 2009

The larvae and puparia ofLimnophora exurdaare to be found in tufts of wet moss or liverworts in or near small waterfalls.The larvae are carnivorous and exhibit the characteristic morphological characters of carnivorous anthomyid larvae.
The morphology and systematic position ofDobellina mesnilinov.gen. (Entamoeba mesniliKeilin, 1917)
Authors: Bishop Ann , Tate P. 
Published: June 2009

1. A detailed morphological study has been made of the amoeba, parasitic in larvae ofTrichocera, which was described by Keilin (1917) under the nameEntamoeba mesnili.2. This study shows that the parasite cannot be included in any of the existing genera of parasitic amoebae and the new genusDobellinais formed for it. A diagnosis of the genusDobellinais given.3. In CambridgeTrichoceralarvae were never found infected withDobellina mesniliearlier in the winter than January and the infection rate appears to be highest (up to 92%) towards the end of January and in February. Infected larvae were never found later in the year than May.
Larval and nymphal mites (Acarina; Trombiculidae) from Ceylon and the maldive islands
Authors: Radford Charles D. 
Published: June 2009

During five months spent in Colombo (April–August 1944) a large number of small mammals and birds were examined for larval Trombiculinae.From November 1944 to February 1945 similar investigations were carried out on the Maldive Islands. The number of species obtained included three species of the genus Gahrliepia Oudemans, 1912 (not included in this paper), Trombicula deliensis Walch, 1923, Trombicula acuscutellaris Walch, 1923, Neoschöngastia indica Hirst, 1915, Walchia turmalis Gater, 1932 (a second species of Walchia not included in this paper), a new species of Schöngastia herein named ‘maldiviensis’ n.sp., and Womersleyia minuta n.g., n.sp.
The Morphology and Method of Division ofTrichomonas
Authors: Bishop Ann 
Published: June 2009

1. Three trichomonads have been cultivated and studied,T. hominis, Trichomonassp. fromM. nemestrinus(= R.T. strain), andT. batrachorumfrom English frogs and toads.2. A number of strains ofT. batrachorumwere cultivated over periods varying from two weeks to five months without the appearance of aEutrichomastixstage.3. The division process ofT. batrachorumhas been studied. The new basal fibre arises as an outgrowth from the blepharoplast. The old axostyle is absorbed and new ones are formed from the daughter blepharoplast during the telophase. Six chromosomes appear during the prophase. Spindle fibres do not appear. There is a separation of the daughter blepharoplasts into centro-some and basal granule at the metaphase.4. Division ofT. hominisandTrichomonassp. fromM. nemestrinusis essentially similar to that ofT. batrachorum. The number of chromosomes appeared to be five or six. Double individuals were found in the cultures, and inT. hominisindividuals containing four or six sets of organellae. Their significance is obscure.
On the Persistence of Eosinophilia, and on Immune Reactions in Human Trichinosis, Several Years after Recovery
Authors: Theiler Hans , Augustine Donald L. , Spink Wesley W. 
Published: June 2009

Following a brief historical introduction, the results of differential counts, precipitin tests and skin reactions on seven cases of trichinosis 4–9 years after recovery are presented. Eosinophile counts ranging from 2 to 7 per cent. were encountered, but the number of cases studied does not warrant any conclusion being drawn. Positive precipitin tests and intradermal reactions were encountered in cases up to 7 years after infection. The findings are discussed, together with a consideration of the pertinent literature, and the importance of the skin reaction and precipitin tests as aids to diagnosis are emphasised in conjunction with due consideration of the history and symptomatology. It is affirmed that the tests have proved of value in establishing a diagnosis in mild cases.It is a pleasure to acknowledge our indebtedness to Dr George R. Minot, who made the records of the hospital available to us, and to Dr W. D. Sutliff, whose continued interest and ready co-operation greatly facilitated our work.
Method of Chain Formation inHerpetomonas bancrofti
Authors: Holmes Francis O. 
Published: June 2009

Stages of incomplete division of chains of individuals in the speciesHerpetomonas bancrofti, as well as the distribution of abnormal cells within long chains, were found to support the writer's earlier view (Holmes, 1931) that successive longitudinal divisions of individuals occur within chains. In this type of division there is alternate splitting of individuals from anterior and from posterior ends of cells. It is concluded that this hitherto unproved type of division of pairs and chains is sufficient to account for the presence of all observed aggregates.No evidence was found suggesting occurrence of any essentially different type of cell division, such as the transverse fission reported by Franchini (1931, 1931a) as possibly accounting for formation of chains inH. ganorae.
Observations Upon Chilomastix from Bufo vulgaris, with notes on Chilomastix aulastomi
Authors: Bishop Ann 
Published: June 2009

1. Chilomastix from Bufo vulgaris has been grown in culture media but a “pure” strain was not obtained. Division and encystment occurred.2. Two types of division were found. In one type the original cytostome and flagella persisted and a new set was formed from one pair of basal granules. In the other type the original cytostome disappeared and two new ones were formed from the two pairs of basal granules. This second type of division is similar to that of Chilomastix aulastomi from Haemopis sanguisuga.3. It is therefore probable that two species of Chilomastix are present in Bufo vulgaris.4. Cysts of Chilomastix from Bufo vulgaris and of Chilomastix aulastomi were studied. Nuclear division was never seen in them.I wish to offer my best thanks to Mr Clifford Dobell, F.R.S., for kindly reading through the manuscript.