bluuebunny/crossref_metadata_2025 huggingface dataset:
Sexual development in malarial parasites: gametocyte production, fertility and infectivity to the mosquito vector
Authors: Dearsly A. L. , Sinden R. E. , Self I. A.
Published: June 2009

Using cloned lines ofPlasmodium bergheiproducing mixed asexual and sexual (clone 234L) and purely asexual (clone 233L) parasitaemias, the courses of parasitaemia, gametocytogenesis, exflagellation, ookinete productionin vitroand mosquito infectivity have been followed. For clone 234L mosquito infectivity is maximal at day 3 and has ceased by day 6 post-infection. Conversely, gametocytogenesis, exflagellation and ookinete production are at minimal levels at day 3 and rise to peaks between days 10 and 15 of infection (in TO mice infected with blood at mechanical blood passage 3). Sexual potential declines progressively with sustained mechanical passage (up to P14). Gametocyte conversion is highest early in infection and declines exponentially; however, upon each mechanical passage conversion is again raised but decreases more rapidly with succeeding passages. For practical mosquito transmission in the laboratory we consider P8to be the useful limit for mechanical transmission for this parasite clone. Asexual parasite growth (virulence) is more rapid with increased mechanical passage inducing a rapid fall in haematocrit. By P14the course of infection closely parallels that of the purely asexual clone 233L.
Genetically-determined influences on the ability of poor responder mice to respond to immunization againstTrichuris muris
Authors: Else K. J. , Wakelin D.
Published: June 2009

Strains of mice poorly (B10) or non-responsive (B10.BR) to a primary infection withTrichuris muriswere protected against infection by vaccination with excretory/secretory (E/S) antigen in Complete Freund's Adjuvant (CFA). Protection in these mice was slow to be expressed compared to that in good responder strains. Vaccination boosted the IgG and IgG1 antibody responses to E/S antigen and altered the antigen recognition profiles, three high molecular weight antigens (80–85, 90–95, 105–110 kDa) being recognized by antibodies in sera from vaccinated but not control mice. B10. BR mice which had experienced a patent primary infection could not be protected against challenge infections by vaccination and this was correlated with depressed levels of IgG1, but not total IgG, to E'S antigen early post-challenge compared with vaccinated infected mice which had not seen an adult primary infection. There was also lack of recognition of the three high molecular weight antigens recognized by antibodies in sera from mice infected after vaccination. It is suggested that the rapid development of high levels of IgG1 antibodies, and the recognition of the three high molecular weight antigens, may reflect events that are important in protective immunity. Immunomodulation of host immunity byT. murismay therefore be achieved, at least in part, by the suppression of specific IgG1 levels, the production of an irrelevant IgG isotype and prevention of the recognition of critical antigens.
Biased sex ratios and parasite mating probabilities
Authors: May R. M. , Woolhouse M. E. J.
Published: June 2009

An earlier paper (May, 1977) developed a theoretical framework for exploring the consequences of dioecy for the population dynamics of schistosomes, assuming an unbiased sex ratio. This paper extends the analysis to biased sex ratios, as have been reported in practice. We consider the relationships of the mean number and distribution of worms among hosts, the sex ratio, and the mating system (monogamous or polygamous) to: (i) the female mating probability, Φ the prevalence of mated female worms. Ω: and (iii) the mean number of mated female worms per host, ξ. Among other results, we show how high values of Φ are associated with male-biased sex ratios and polygamous mating; that Ω is independent of the mating system and is relatively unaffected by the sex ratio; and that ξ is maximal for unbiased sex ratios given monogamous mating, and for female-biased sex ratios if mating is polygamous. These results, together with the confounding effects of the mean number and distribution of worms, are described in detail in the main body of the paper.
Frequency of cross-fertilization in the human malaria parasitePlasmodium falciparum
Authors: Ranford-Cartwright L. C. , Balfe P. , Carter R. , Walliker D.
Published: June 2009

Two clones of the human malaria parasitePlasmodium falciparum, denoted 3D7 and HB3, were grownin vitrounder conditions permitting the development of gametocytes. The two clones differ in their allelic forms of two antigen genes MSP1 and MSP2. The alleles can be distinguished as size differences of polymerase chain reaction (PCR) amplified fragments of repetitive regions of each gene. Mosquitoes (Anopheles stephensi) were fed on a mixture of these gametocytes. A total of 128 oocysts was isolated from the midguts of infected mosquitoes from 9 crossing experiments between the clones. DNA extracted from these oocysts was amplified by PCR. Oocysts which contained both alleles of each gene (MSP1 and MSP2) had developed from heterozygotes produced by cross-fertilization events between 3D7 and HB3 gametes. The remaining oocysts contained single alleles of each gene, in parent clone combinations, and these had developed from homozygotes formed by self-fertilizations. The results suggest that gametes in the original mixture fed to mosquitoes had undergone random mating.
Characterization ofMegatrypanumtrypanosomes from European Cervidae
Authors: Böse R. , Petersen K. , Pospichal H. , Buchanan N. , Tait A.
Published: June 2009

Megatrypanumtrypanosomes have been isolated from a number of different European Cervidae, but on the basis of morphology it has not been possible to define the species to which these isolates belong. We isolatedTrypanosoma (Megatrypanum) theilerifrom 10 cattle, andMegatrypanumtrypanosomes from 11 fallow deer (Cervus dama), 9 red deer (Cervus elaphus), and 4 roe deer (Capreolus capreolus) by blood culture on a biphasic medium (NNN agar slopes). Trypanosomes were propagated in Schneider's Drosophila medium and characterized by isoenzyme analysis and molecular karyotyping. Isocitrate dehydrogenase and phosphoglucomutase were visualized after starch gel electrophoresis of trypanosome lysates. By cluster analysis of this data all isolates from deer were clearly separated from theT. (M.) theileriisolates from cattle. Isolates from roe deer were different not only fromT. (M.) theileribut also from the other deer isolates. Isolates from fallow deer and red deer were grouped together. Thus, there are probably at least two different species ofMegatrypanumtrypanosomes in the three Cervidae. One parasitizing roe deer, the other, apparently less host specific species, infecting red deer and fallow deer. Separation of the chromosomes ofMegatrypanumtrypanosomes by pulsed-field gradient gel electrophoresis (PFGE) showed that each isolate contained a large number (> 18) of chromosomes ranging in size from 300 to > 2200 kb. The molecular karyotypes were similar for all isolates, although no isolate was identical to another.
The influence of second intermediate host dispersion pattern upon the transmission of cercariae of Echinoparyphium recurvatum (Digenea: Echinostomatidae)
Authors: McCarthy A. M.
Published: June 2009

Transmission of cercariae of the echinostome digenean Echinoparyphium recurvatum was observed in experimental populations of the second intermediate host snail Lymnaea peregra. Populations of 100 snails were distributed among plastic mesh cages in an infection arena to produce different patterns of host dispersion. Cercarial transmission was investigated in host populations showing three separate patterns of host dispersion; Ideal Regular, Random and Contagious (‘Clumped’). Levels of cercarial transmission in populations showing each type of dispersion pattern were found to be significantly different. The highest rate of cercarial transmission occurred in the contagiously dispersed host population, and the lowest in the randomly dispersed population. Analysis of results from the randomly dispersed population also showed that both the mean percentage prevalence of infection, and also the mean number of cysts recovered per snail, increased significantly with the number of snails per cage. The positive relationship between the mean number of cysts per snail and the number of snails per cage was found to be best described by an exponential function. Chemosensory location of L. peregra snail hosts by E. recurvatum cercariae may provide an explanation for the patterns of cercarial transmission observed.
An experimental and theoretical study of the dynamics of a mouse – nematode (Heligmosomoides polygyrus) interaction
Authors: Scott M. E.
Published: June 2009

The population dynamics of outbred laboratory mice in indoor enclosures in the absence and presence of a naturally transmitted direct life-cycle nematode Heligmosomoides polygyrus Dujardin 1845 were reported previously. This manuscript presents further information on the age and sex structure of the populations, results of experiments designed to estimate the density-dependent effect of the parasite on host survival and reproduction, and a mathematical model of both uninfected and infected mouse populations. In the uninfected mouse population, survival of female mice was age- and density-independent, survival of male mice was age-dependent and density-independent, and recruitment was density-dependent. Independent experiments revealed that the parasite had no density-dependent effect on mouse reproduction, but had density-dependent effects on both acute and chronic survival of mice. An age-structured Leslie matrix model captured the exponential growth and plateau of the uninfected mouse population. Modification of the model to incorporate the effects of the parasite provided a good fit to the data from the infected populations, supporting the hypothesis that density-dependent effects of the parasite on host survival could lead to regulation of host abundance.
Carbohydrate reserves and infectivity in Trichinella spiralis isolated from carrion
Authors: Raines Karen M. , Stewart G. L.
Published: June 2009

Trichinous mice were killed and their carcasses maintained at room temperature or subzero temperatures for varying lengths of time. Some worm parameters were measured after direct isolation from carcasses while others were measured following passage through a second round of hosts. Glycogen and trehalose levels in infective 1st-stage larvae (L1) isolated directly from carcasses maintained at room temperature were significantly less than controls (day 0) after day 4 post-kill (p.k.). By day 21 p.k. among L1 isolated directly from mouse carcasses those observed coiled or moving had decreased by around 20% compared to day 0 p.k. The percentage of L1 isolated from carcasses on several days p.k., used to infect mice and recovered as pre-adult worms declined significantly after they had remained in carcasses for 14 days. Only 2·6% of muscle larvae isolated from carcasses on day 21 p.k. and used to infect mice were recoverable as pre-adults. Pre-adult worms raised in mice infected with larvae from day 7 carcasses had about 50% less glycogen than worms raised in mice infected with larvae isolated from fresh carcasses (day 0 p.k.). The fecundity in vitro of adult worms isolated from mice on day 7 following infection with infective L1 larvae maintained in carcasses held at room temperature for 0–16 days declined only when adult worms developed from larvae recovered from carcasses at 3 days following host death. Following 24 h at temperatures below freezing, infectivity of L1 larvae isolated from frozen carcasses was reduced by 97%. Carbohydrate levels remained high in larvae from carcasses frozen for up to 4 days.
Polychromophilus murinus: a malarial parasite of bats: life-history and ultrastructural studies
Authors: Gardner R. A. , Molyneux D. H.
Published: June 2009

Polychromophilus murinus, a malaria parasite of Chiroptera is reported from Myotis daubentoni in England. The vector was suspected to be the ectoparasitic Nycteribiid fly, Nycteribia kolenatii. N. kolenatii collected from wild-caught M. daubentoni were found to have oocysts on the midgut and sporozoites in the salivary glands. Wild-caught N. kolenatii were maintained on two wild-caught M. daubentoni harbouring heavy (patent) infections of P. murinus; both oocysts and sporozoites were found in these flies. The mature oocysts measured 52–71 μm in diameter. Sporozoites were straight or slightly crescentic and had a mean length of 7·4 μm. Electron microscopy of immature and mature oocysts revealed a morphology similar to that of malaria parasites. Sporozoites were also similar in structure to Plasmodium sporozoites and were found in the epithelial cells of the salivary gland and within the lumen; a cytostome was present and transverse sections revealed 21 microtubules arranged evenly around the periphery. Sporozoites were observed within the basement membrane of the salivary gland of N. kolenatii; such sporozoites appeared to be penetrating the gland, a process hitherto not described in malaria parasites. Rickettsia-like bodies were found within the cytoplasm of the epithelial cells of the salivary gland. Exflagellation of microgametocytes was achieved. An ultrastructural study of the gametocytes revealed a structure similar to that described in other Haemoproteidae. A common feature of infected erythrocytes was a projecting erythrocyte membrane. Attempts to find schizogony in impression smears and sections of tissues of two infected M. daubentoni were not successful.
A genetic analysis of reproduction in Strongyloides ratti
Authors: Viney M. E.
Published: June 2009

Strongyloides ratti has a complex life-cycle with two adult generations, one free-living and dioecious and one parasitic and female only. The parasitic females reproduce by parthenogenesis, but it is unclear whether this is mitotic or meiotic in nature. This question has been addressed genetically by analysing the progeny of parasitic females that were heterozygous at an actin locus for evidence of allelic segregation. Such progeny were similarly heterozygous showing that segregation had not occurred. It was therefore concluded that reproduction in the parasitic female of S. ratti is functionally mitotic.
Age-prevalence and household clustering ofStrongyloides stercoralisinfection in Jamaica
Authors: Lindo J. F. , Robinson R. D. , Terry S. I. , Vogel P. , Gam A. A. , Neva F. A. , Bundy D. A. P.
Published: June 2009

The epidemiology ofStrongyloides stercoraliswas studied in families of clinical (reference) cases and their neighbours at endemic foci in Jamaica. Thirteen foci were studied based on the place of residence of a reference case. For each household of a reference case, the 4 most proximal neighbourhood households (spatial controls) were included in the study. Out of 312 persons contacted 244 were followed up using questionnaires, stool examination and serology. Prevalence of infection based on stool examination was 3·5% and on ELISA 24·2%. Prevalence increased with age but was not related to gender. Reference cases were significantly older than the general study population. The prevalence of infection based on both serology and stool examination was significantly higher in reference than in neighbouring households (the reference cases, themselves, were not included in the analysis). Furthermore, prevalence of infection was highest among persons who shared a bedroom with a reference case and decreased significantly with increasing spatial separation. This is indicative of close contact transmission which has not been previously shown for a geohelminth, but which is common among microparasites.
Parasites of wild brown rats (Rattus norvegicus) on UK farms
Authors: Webster J. P. , Macdonald D. W.
Published: June 2009

Wild brown rats (Rattus norvegiens) from 11 rural UK farmsteads were found to carry 13 zoonotic and 10 non-zoonotic parasitic species, many of which (e.g.Cryptosporidium, Pasteurella, Listeria, Yersinia, CoxiellaandHantavirus) have rarely or never been previously investigated for wild rats. The study suggests that wild brown rats, serving as vectors of disease, represent a serious risk to the health of humans and domestic animals in the UK.
Susceptibility of brook charr,Salvelinus fontinalisto the pathogenic haemoflagellate,Cryptobia salmositica, and the inheritance of innate resistance by progenies of resistant fish
Authors: Forward G. M. , Ferguson M. M. , Woo P. K. T.
Published: June 2009

Eighty-seven of 175 laboratory raised F1 generation brook charr (Salvelinus fontinalis) were resistant to experimentalCryptobia salmositicainfection. Susceptibility to the pathogen was not related to age nor to route of infection. Plasma of resistant charr lysed the parasite underin vitroconditions while those of susceptible fish did not. Sperm from 4 susceptible and 4 resistant male charr, from 8 F1 families, were used to fertilize eggs from 2 hatchery raised susceptible charr. Susceptibility of progenies (F2 families) was determined 4 weeks after inoculation of the parasite. All progenies (seven F2 families) of 4 susceptible males were susceptible to experimental infection and their plasma did not lyse the parasite. It was presumed that these susceptible progenies were homozygous recessive (rr), and that the resistant allele was dominant. All progenies (two F2 families) of 1 resistant male (presumed RR) and 2 susceptible females were all resistant to infection and their plasma lysed the parasite. The ratio of resistant to susceptible charr in 6 other F2 families from the other 3 resistant males (presumed Rr) and two susceptible females was about 1:1. The results suggest a single Mendelian locus which determines innate resistance toC. salmositicainfection in brook charr and that it is possible to breedCryptobia-resistant fish.
The effect of two types of diet on populations ofAscaris suumandOesophagostomum dentatumin experimentally infected pigs
Authors: Petkevicius S. , Bjørn H. , Roepstorff A. , Nansen P. , Knudsen K. E. Bach , Barnes E. H. , Jensen K.
Published: June 2009

This investigation compared the effect of two common types of diet on worm burdens and faecal egg counts of pigs inoculated withAscaris suumandOesophagostomum dentatum. The diets were both considered nutritionally sufficient for pigs of this age, and gave high and comparable growth rates. Pigs were inoculated with both worm species at 14 weeks of age and slaughtered 3 or 12 weeks later. At 3 weeks,A. suumlarvae were numerous in the small intestine of pigs fed ground barley plus protein supplement, but were not detected from pigs fed a commercial full-constituent pelleted feed. At 12 weeks, however, average adult worm burdens were low and similar in both groups. At both slaughter times,O. dentatumworm burdens were significantly higher in pigs fed barley plus protein than in pigs given commercial feed, particularly for female worms, and the commercial diet led to worms being located further along the large intestine, and to reduced worm fecundity. The chemical composition of large intestinal contents differed significantly between pigs fed the two diets.
An analysis of the molluscan hosts of the trematodes of birds and mammals and some speculations on host-specificity
Authors: Ewers W. H.
Published: June 2009

Data on 279 species of trematodes of birds and mammals are analysed in tables, to show the molluscan orders and families that act as first intermediate hosts of various trematode families.

Host-specificity is highly developed in the first larvae of trematodes and it is suggested that, as a consequence of this, certain species, genera and families of molluscs harbour a greater variety of trematodes than others. The families Lymnaeidae, Physidae, Planorbidae, Hydrobiidae and Thiaridae are by far the most important first-intermediate hosts of the trematodes of birds and mammals whose life cycles are known; each family acting as host of not less than twenty-four species and eight families of trematodes.

This paper is published with the approval of the Director General of Health, Canberra, A.C.T.
Schistosoma mansoni: in vivoandin vitrostudies of immunity using the guinea-pig model
Authors: Pearce E. J. , McLaren Diane J.
Published: June 2009

In vivoandin vitroparameters of immunity have been assessed in guinea-pigs sensitized with 500 normal or 500 radiation-attenuated cercariae ofSchistosoma mansoni. High levels of resistance to a challenge infection developed in both the chronic and irradiated vaccine model, but immunity was expressed earlier (week 4) and reached higher levels (90%) in the latter case. Vaccinated guinea-pigs have thus been shown to achieve greater resistance than the more commonly used rodent hosts.In vitrocytotoxicity assays have demonstrated that antibodies capable of participating in complement-dependent (lethal antibody) or eosinophil-mediated schistosomular killing, develop in the serum of guinea-pigs immunized with either normal or irradiated cercariae. The time course of development of the eosinophil adherence promoting antibody approximated in both models, the development of immunityin vivo, but the lethal antibody response paralleled the immune status of the animal only in the irradiated vaccine model
The water relations of the larva of Xenopsylla cheopis (Siphonaptera)
Authors: Sharif M.
Published: June 2009

A considerable loss of water in the flea larva, through its defaecation and excretion as the result of the absence of rectal glands, through a profuse evaporation from the surface cuticle on account of its being a soil inhabitant, and from its tracheal system owing to the absence of an efficient closing apparatus of the spiracles, is compensated by the absorption of water with the food and through the cuticle, and by the utilization of metabolic water.

It has been proved, by conducting experiments on the food composed of dried horse blood and yeast, with different degrees of moisture contents, and by controlling the quantity of the desiccated food and the duration of its exposure to a low effective humidity of 60% at 22° C., that the chief source of the gain of water in the larva of Xenopsylla cheopis is through the food.

The closing mechanism of the spiracles of the flea larva plays only a small part in the control of evaporation at medial temperatures but not at extreme ones.

There are intrinsic differences in the water requirements of the flea larvae of the two sexes, being slightly less in the male larva than in the female larva.

I am greatly obliged to Lt.-Col. Sir Sahib Singh Sokhey, Director, Haffkine Institute, Bombay, for affording me facilities for the pursuit of these investigations. Mr T. N. Raste has helped me in the calculation of the data statistically, for which I am grateful to him.
The effect of physical agents on hydatid scolex viability
Authors: Fastier L. B.
Published: June 2009

By employing a combination of sub-stage heating and supra-vital staining with eosin or neutral red it was found that viable and non-viable hydatid scolices could be distinguished microscopically. Using this technique a study of the effect of heat in vitro on hydatid scolices has shown that death resulted from exposures at 50° C. for 70 min. and at 55° C. for 30 min.

Experiments on the effect of boiling in destroying the contents of fertile cysts embedded in sheep liver showed that when offal was added directly to boiling water destruction of scolices was complete after 40 min. boiling. When the infected liver was placed in cold water brought to the boil, scolex death was assured only after 30 min. subsequent boiling.

Ultra-violet radiations of 2537 A. did not kill scolices under the conditions adopted. Although this wave-length would apparently be ineffective as a scolicicidal agent in surgery of the human hydatid cyst, irradiation of hydatid fluid containing scolices might offer a simple method for initial sterilization of scolex culture media.

The author wishes to acknowledge many helpful suggestions and loan of the Hanovia lamp by Dr G. M. Richardson of the Virus and Immunology Research Department, Otago Medical School.
Trypanosoma uniforme-Trypanosoma vivax infections in bovines and Trypanosoma uniforme infections in goats and sheep at Entebbe, Uganda
Authors: Wilson S. G.
Published: June 2009

In the course of recent work on the pathogenicity of Trypanosoma vivax in bovines, cases have occurred at the Veterinary Laboratory, Entebbe, when it has been difficult to diagnose the species of trypanosome occurring in the blood. This difficulty arose because many of the trypanosomes were too small to be typical T. vivax and the possible occurrence of T. uniforme had to be considered, and also because many abnormal degenerate forms appeared at irregular intervals. A more detailed study of the trypanosomes present in the infection was therefore undertaken and, although in many aspects this work is still incomplete, the course of the infection in goats and sheep has been sufficiently interesting to merit this preliminary report.
The scutum of the tick, Ixodes ricinus L.
Authors: Arthur D. R.
Published: June 2009

It is a common observation that in individual Ixodes ricinus L. ticks, size variations occur; such variation is reflected in the records of early workers (Wheler, 1899; Neumann, 1899: quoted by Nuttall, Warburton, Cooper & Robinson, 1911). The present paper attempts to examine the true specific importance of size variation by basing the study on measurements of the relatively inelastic scuta after the principle of using head capsule measurements for insectan larval instars.
Reactions of Cyphomandra betacea to strains of potato virus X
Authors: Matthews R. E. F.
Published: June 2009

During the course of work carried out in 1941 at the Plant Diseases Division, Auckland, N.Z., on a mixture of X strains in Red Dakota potatoes, it was found that among the twenty solanaceous species tested in host range studies, Cyphomandra betacea gave an anomalous reaction.
Lernaea chackoensis n.sp.: a copepod parasitic on two Madras fishes
Authors: Gnanamuthu C. P.
Published: June 2009

Since 1925, when Leigh-Sharpe described Lernaea elegans, the first Asiatic species from Anguilla japonica, four more species were recorded from China and Japan. The species described in the present paper, while differing from these and other known species, forms the first record of the genus from India. Five parasites attached to three fishes (Osphronemus goramy) and twelve removed from their hosts, together with two fish (Catla catla) infested by about eighteen parasites formed the material examined. Colonies of a vorticellid (Carchesium sp.) were found attached to the external portions of the parasites. In some the stalks of the epizoans were woven through by Algae such as Oscillaria, Lyngbya and Calothrix, enmeshing other algae like Cosmaria, Oedogonium and diatoms, and a matted covering was thus formed round the bodies of the parasites.
A study of the vector-parasite relationships in Schistosoma mansoni
Authors: Files Virginia S.
Published: June 2009

In this study Australorbis glabratus from Puerto Rico, the Dominican Republic, Venezuela, Surinam and Brazil, Biomphalaria pfeifferi from Liberia, and B. boissyi from Egypt were exposed to strains of Schistosoma mansoni from Puerto Rico, Venezuela, Surinam and Egypt, and to seven cross-strains of S. mansoni. In many instances, incompatibilities between vectors and parasites of different endemic areas were noted. It is suggested that these incompatibilities might be accounted for in two ways: (1) interspecific and intraspecific differences between vectors in respect to the physiological factors that are responsible for the development of the parasite in the snail, and (2) physiological differences between strains of the parasite. Evidence would seem to show that there are interspecific physiological differences between Australorbis glabratus and Biomphalaria boissyi; and that there are intraspecific differences between Australorbis glabratus from Brazil and A. glabratus from other countries here dealt with. In addition, it would appear that the parasite of Egypt differs physiologically from the parasites of Puerto Rico, Venezuela and Surinam; and that the parasite of Brazil differs physiologically from the parasites of the latter countries.

We wish to express our gratitude to the following persons for their co-operation in collecting and shipping snails for this study: Drs M. Abdel Azim, C. H. Barlow, J. O. Coutinho, A. Gabaldon, the late W. A. Hoffman, G. W. Luttermoser, J. Oliver-Gonzalez, H. A. Poindexter, Bichat de Almeida Rodriques and A. E. Wolff. We are also indebted to the late Dr W. A. Hoffman, Dr M. Mayer and Dr J. Alves Meira for sending us animals infected with Schistosoma mansoni.
Remarks on theilerioses and Theileria
Authors: Dschunkowsky E.
Published: June 2009

1. Areas in which theileriasis occurs are characterized by conditions in which the native cattle do not show clinical manifestations of the disease, but introduced cattle suffer from an epizootic manifesting itself seasonally with varied intensity.

2. The degree of virulence exhibited and the species of tick acting as vectors have only an indirect significance as an indication of species of the parasite.

3. The facts relating to the development of Theileria in the tissues of infected animals and relation of this to developmental stages in the circulating blood are still far from clear.

4. The development cycle of Theileria in the red cells of the circulating blood of sick animals is described, and proof given that this is characterized by the formation of anaplasmatic forms developing into ring-shaped forms in T. annulata and T. dispar, and probably in all forms except, possibly, T. parva.

5. It is very desirable from the point of view of world economy that a special commission to study theileriasis in the different areas in which it occurs should be established on an international basis.
The ecology of immature phases of trichostrongyle nematodes: IV. Larval populations on lowland pastures
Authors: Crofton H. D.
Published: June 2009

1. Permanent and temporary pastures were examined using a modification of Taylor's method.

2. The goodness of fit of Neyman's Contagious Distribution Type A when applied to larvae on pastures is discussed.

3. Examination of permanent pastures over a period of 3 years showed that the difference in time of maximum infestation was greater between fields in the same year than between years for the same field.

4. Counts made on pastures where disease had occurred showed reasonably close agreement with Taylor's estimate.

5. No larvae were detected on fields after ploughing and reseeding.

6. The number of larvae per lb. of herbage on reseeded pastures was low, but the growth of grass masked the fact that the total population was relatively high at the end of the season.
Four new species of parasitic mites (Acarina)
Authors: Radford Charles D.
Published: June 2009

In this paper four new mites are described and figured, one being a new species of the subfamily Macronyssidae, one in the subfamily Laelaptinae and two in the family Trombiculidae.
The action of 2:4-diamino-6:7-diisopropylpteridine on normal, proguanil- and sulphadiazine-resistant strains ofPlasmodium gallinaceum
Authors: McConnachie Elspeth W.
Published: June 2009

1. 2:4-diamino-6:7-diisopropylpteridine has an antimalarial index of 1:40, when tested againstPlasmodium gallinaceum.

2. 2:4-diamino-1′-methylindolo-(2′:3′-6:7)-pteridine showed no activity againstP. gallinaceumin doses tolerated by the chick.

3. Proguanil- and sulphadiazine-proguanil-resistant strains ofP. gallinaceumwere cross-resistant to 2:4-diamino-6:7-diphenylpteridine.

4. Proguanil- and sulphadiazine-proguanil-resistant strains ofP. gallinaceumshowed no cross-resistance to 2:4-diamino-6:7-diisopropylpteridine, but were slightly hypersensitive to this compound.

I wish to thank Dr A. Bishop for her interest in this work, and for advice and criticism. The work has been financed by the Medical Research Council.
Art and Moralism
Authors: Taylor Craig
Published: June 2009

Mrs. Digby told me that when she lived in London with her sister, Mrs. Brooke, they were every now and then honoured by the visits of Dr. Johnson. He called on them one day soon after the publication of his immortal dictionary. The two ladies paid him due compliments on the occasion. Amongst other topics of praise they very much commended the omission of all naughty words. ‘What! my dears! then you have been looking for them?’ said the moralist. The ladies, confused at being thus caught, dropped the subject of the dictionary. (H.D. Best, Personal and Literary Memorials, London, 1829, printed in Johnsonian Miscellanies Vol. 2, G. Birkbeck Hill (ed.) (London: Constable & Co.,1897))
Plato on Conversation and Experience
Authors: Robertson David
Published: June 2009

Plato's dialogues show discourse strategies beyond purely intellectual methods of persuasion. The usual assumption is that linguistic understanding depends on a match of inner experiences. This is partly explained by an underlying engagement with the historical Gorgias on discourse and psychology, as well as Parmenides on philosophicallogos. In theGorgiasand theSymposium, speakers cannot understand alien experiences by philosophical conversation alone. There is no developed alternative model of understanding in the Platonic dialogues. The difficulties in bringing ‘philistine souls’ into Socratic alignment are the result of possessing an inferior soul, suffering misdirected passions, or missing the philosophy bug.
Presidential Address
Authors: Duff Mountstuart E. Grant
Published: June 2009

Two years ago, I had the honour to attempt, in addressing you, to answer the question how far Thucydides was of value to the modern statesman. I have recently been re-reading Herodotus, not precisely with a view to answer the same question in reference to him, but still not without keeping it, to some extent, before my mind. I purpose accordingly, this afternoon, to lay before you some of the considerations which have occurred to me with regard to his famous Enquiries; for ‘Enquiries’ or ‘Researches’, rather than Histories, ought perhaps to be the English rendering of the title of his famous book.
Strengthening primary health care and health promotion in Sri Lanka's schools: need for a comprehensive national policy
Authors: de Silva Umanga , Barraclough Simon
Published: June 2009

School children constitute ~20% of the population in Sri Lanka, making school health an important element in primary health care in this country. Sri Lanka faces severe economic problems, the challenge of reducing health inequalities within its society and a continuing ethnically based armed conflict. Historically, the school health program emphasised hygiene, screening for diseases and malnutrition and referrals to specialists. However, many interrelated factors influence the physical, mental and social health of school children. Schools should therefore provide not only a healthy physical setting, but also healthy social and emotional environments that promote better learning. This article uses both published and unpublished official documents, as well as a review of recent local research to present a comprehensive overview of school health programs in Sri Lanka, to identify problems with their content and implementation and to suggest ways for strengthening them. It is argued that there is a pressing need for a comprehensive national school health policy that not only addresses the essentials of planning and coordination, but also serves to reorient school health to embrace the promotion of physical and psychosocial health. Such a shift should be based on a whole-of-school approach, recognising the role of students, teachers and the wider community.
Understanding help seeking for mental health in rural South Australia: thematic analytical study
Authors: Collins Joanne E. , Winefield Helen , Ward Lynn , Turnbull Deborah
Published: June 2009

This study investigated barriers to help seeking for mental health concerns and explored the role of psychological mindedness using semistructured interviews with sixteen adults in a South Australian rural centre. Prior research-driven thematic analysis identified themes of stigma, self-reliance and lack of services. Additional emergent themes were awareness of mental illness and mental health services, the role of general practitioners and the need for change. Lack of psychological mindedness was related to reluctance to seek help. Campaigns, interventions and services promoting mental health in rural communities need to be compatible with rural cultural context, and presented in a way that is congruent with rural values.
Preliminary description and nutritional characterization of a chemoorganotrophic archaeobacterium growing at temperatures of up to 110 ° isolated from a submarine hydrothermal vent environment
Authors: Pledger Ralph J. , Baross John A.
Published: June 2009

Summary: An extremely thermophilic coccoid bacterium, designated strain ES4, was isolated from a flange (a newly described geological structure associated with massive sulphide mounds) at the Juan de Fuca Ridge hydrothermal vent system. The organism is a salt-requiring obligately anaerobic chemoorganotroph which reduces elemental sulphur but can grow very poorly in the absence of sulphur. Organic substrates utilized include yeast extract, peptone and amino acid hydrolysate as well as individual amino acids, the peptide Leu-Ser and starch. When growing on a defined medium, ES4 requires a supplement of vitamins and 20 amino acids at trace concentrations. Growth is most rapid in the temperature range 90-99 °C, with a maximum growth temperature of about 110 °C. In the optimal temperature range for growth, ES4 has a doubling time of about 1 h and can reach densities of 109 cells ml-1. Insensitivity to the antibiotics vancomycin, streptomycin and chloramphenicol, and the presence of di- and tetra-ether phytanyl lipids, indicate that ES4 is an archaeobacterium.
Phospholipase-A-independent damage caused by the colicin A lysis protein during its assembly into the inner and outer membranes of Escherichia coli
Authors: Howard S. Peter , Cavard Danièle , Lazdunski Claude
Published: June 2009

Summary: The requirement for the activation of phospholipase A by the colicin A lysis protein (Cal) in the efficient release of colicin A by Escherichia coli cells containing colicin A plasmids was studied. In particular, we wished to determine if this activation is the primary effect of Cal or whether it reflects more generalized damage to the envelope caused by the presence of large quantities of this small acylated protein. E. coli tolQ cells, which were shown to be leaky for periplasmic proteins, were transduced to pldA and then transformed with the recombinant colicin A plasmid pKA. Both the pldA and pldA
+ strains released large quantities of colicin A following induction, indicating that in these cells phospholipase A activation is not required for colicin release. This release was, however, still dependent on a functioning Cal protein. The assembly and processing of Cal in situ in the cell envelope was studied by combining pulse-chase labelling with isopycnic sucrose density gradient centrifugation of the cell membranes. Precursor Cal and lipid-modified precursor Cal were found in the inner membrane at early times of chase, and gave rise to mature Cal which accumulated in both the inner and outer membrane after further chase. The signal peptide was also visible on these gradients, and its distribution too was restricted to the inner membrane. Gradient centrifugation of envelopes of cells which were overproducing Cal resulted in very poor separation of the membranes. The results of these studies provide evidence that the colicin A lysis protein causes phospholipase A-independent alterations in the integrity of the E. coli envelope. These alterations are required for the breakdown of the permeability barrier leading to colicin export.
Characterization of a new thermostable direct haemolysin produced by a Kanagawa-phenomenon-negative clinical isolate of Vibrio parahaemolyticus
Authors: Honda* Takeshi , Abad-Lapuebla Marimin A. , Ni Yuxin , Yamamoto Koichiro , Miwatani Toshio
Published: June 2009

The production of two haemolysins, thermostable direct haemolysin (Vp-TDH) and a Vp-TDH-related haemolysin (Vp-TRH), by clinical isolates ofVibrio parahaemolyticushas previously been reported. Here we describe a third type of haemolysin (named Vp-TDH/I), which is produced by a clinical isolate (strain TH012) that is Kanagawa phenomenon negative. Vp-TDH/I was purified by a series of column chromatographies on DEAE-Sephadex A25, hydroxyapatite, Sepharose 4B and Mono Q. By physicochemical, biological and immunological analyses, Vp-TDH/I was demonstrated to be similar, but not identical, to Vp-TDH and Vp-TRH. The gene encoding Vp-TDH/I was cloned and the deduced amino acid sequence of Vp-TDH/I confirmed that Vp-TDH/I has a sequence different from those of previously known Vp-TDH and Vp-TRH. Not only purified Vp-TDH/I but also live cells of the Vp-TDH/I-producing strain induced fluid accumulation in ligated rabbit intestine. We conclude that this clinical isolate produces a new type of Vp-TDH-related haemolysin, which may be involved in the pathogenesis of this organism.
Regulation of invertase in Aspergillus nidulans: effect of different carbon sources
Authors: Vainstein Marilene H. , Peberdy John F.
Published: June 2009

Aspergillus nidulansproduces an extracellularβ-d-fructofuranoside fructohydrolase (invertase) when grown on a medium containing theβ-fructofuranosides sucrose or raffinose, indicating that synthesis is subject to induction by the substrate. On a growth medium containing sucrose, production was maximal at 15 h in cultures incubated at 28 C°. After this time the level of detectable invertase in the cultures declined. A proportion of the enzyme was secreted during the linear growth phase of the fungus. Various sugars were investigated for induction of invertase, but only the twoβ-fructofuranosides induced high production levels; with the other sugars, the enzyme was produced only at a low constitutive level. Mycelium grown under repressive conditions (1% glucose), rapidly produced invertase when transferred to sucrose-containing medium. After 80 min the invertase level in these cultures was 26-fold higher than the constitutive level. The repressive effect of other sugars, e.g. glucose and xylose, on invertase production was also demonstrated in this experimental system.
Fatty acid analysis of phytopathogenic coryneform bacteria
Authors: Henningson Paul J. , Gudmestad Neil C.
Published: June 2009

The classification of plant-pathogenic coryneform bacteria has been revised many times. All plant-pathogenic coryneform bacteria were once classified in the genus Corynebacterium. Currently, all are classified in the genera Arthrobacter, Clavibacter, Curtobacterium or Rhodococcus. Difficulties still remain regarding the characterization of species and subspecies within these groups. Analysis of cellular fatty acids by high-resolution capillary gas chromatography has recently become a standard method of bacterial identification in many laboratories. In the studies reported here, cellular fatty acid analyses were performed to examine the plant-pathogenic coryneform bacteria as an autonomous group. A total of 189 bacterial strains were profiled. Results from these studies support the division of plant-pathogenic coryneforms into four major groups (genera). Further subdivision was not required for Rhodococcus and Arthrobacter, as each genus contains only one species of plant-pathogenic bacteria. Some, but not all, Curtobacterium pathovars could be differentiated from one another based on fatty acid analysis alone. Infrasubspecific classification of plant-pathogenic Curtobacterium organisms appears to be appropriate. Most of the species or subspecies belonging to the genus Clavibacter could be differentiated using fatty acid profiles. Other chemotaxonomic methods also differentiate organisms within Clavibacter. Reclassification is warranted within Clavibacter michiganense. Clavibacter michiganense subspecies should be returned to full species status.
Streptomyces akiyoshiensis differs from other Gram-positive bacteria in the organization of a core biosynthetic pathway gene for aspartate family amino acids
Authors: Le Yunzheng , He Jianyong , Vining Leo C.
Published: June 2009

A partial Sau3Al digest of genomic DNA from Streptomyces akiyoshiensis was cloned in a Streptomyces-Escherichia coli
shuttle vector, and the recombinant plasmids were used to transform E. coli CGSC 6212, which carries a mutation in the gene for aspartate semialdehyde dehydrogenase (Asd). One of 39000 transformants tested grew on LB medium lacking diaminopimelate. A 17 kb plasmid (pJV21) isolated from this strain conferred prototrophy when used to transform E. coli CGSC 6212. The gene responsible was located on a 2.2 kb DNA fragment by subcloning. Nucleotide sequencing and codon preference analysis of the subcloned insert and of the 3.3 kb insert in the Asd -complementing plasmid pJV36 located three complete and two incomplete open reading frames (ORFs). One of these (ORF3), encoding a polypeptide of 338 amino acids (M
r 35484), was identified as the gene for Asd by comparing its sequence with database sequences of asd from other bacteria. The inability of pJV30, in which a segment of ORF3 had been deleted, to transform E. coli CGSC 6212 to prototrophy supported this assignment. Southern hybridization indicated that the sequenced region of the cloned DNA fragment represented a continuous segment of the S. akiyoshiensis chromosome. The deduced amino acid sequences of the ORFs adjacent to asd showed no similarity to sequences for aspartate kinase (Ask); also, transformation with plasmids containing asd and adjacent regions from the S. akiyoshiensis chromosome did not complement the ask mutant E. coli CGSC 5074. It is concluded that asd and ask in S. akiyoshiensis are not present in an operon, and thus are organized differently from these genes in the Gram-positive bacteria previously examined.
Codon usage in the Mycobacterium tuberculosis complex
Authors: Andersson Siv G. E. , Sharp Paul M.
Published: June 2009

The usage of alternative synonymous codons in Mycobacterium tuberculosis (and M. bovis) genes has been investigated. This species is a member of the high-G + C Gram-positive bacteria, with a genomic G + C content around 65 mol%. This G + C-richness is reflected in a strong bias towards C- and Gending codons for every amino acid: overall, the G + C content at the third positions of codons is 83%. However, there is significant variation in codon usage patterns among genes, which appears to be associated with gene expression level. From the variation among genes, putative optimal codons were identified for 15 amino acids. The degree of bias towards optimal codons in an M. tuberculosis gene is correlated with that in homologues from
Escherichia coli
and Bacillus subtilis. The set of selectively favoured codons seems to be quite highly conserved between M. tuberculosis and another high-G + C Gram-positive bacterium, Corynebacterium glutamicum, even though the genome and overall codon usage of the latter are much less G + C-rich.