bluuebunny/crossref_metadata_2025 huggingface dataset:
Microspines on Schistosoma japonicum and S. haematobium egg shells
Authors: Schnitzer Bertram , Sodeman Thomas , Sodeman William A. , Durkee Thomas
Published: June 2009

Microspines 0·05 μm long and 0·002 μm in diameter at the base have been demonstrated on the egg shells of S. japonicum. They are protrusions of the shell but are structured into inner and outer layers of differing electron density.

Spines observed on the shell of S. haematobium can be flexed by contact with host cell membranes. Firm, perhaps binding, contact is suggested. The spine length serves to define a space between the shell wall and the host cell membrane which could represent the primary interface of host parasitic contact.
Effect of Toxoplasma gondii upon neophobic behaviour in wild brown rats, Rattus norvegicus
Authors: Webster J. P. , Brunton C. F. A. , Macdonald D. W.
Published: June 2009

The effect of Toxoplasma gondii on neophobic behaviour (the avoidance of novel stimuli) was assessed in four groups of wild rats with naturally occurring Toxoplasma infection. Two groups were placed in individual cages and tested in a series of experiments which examined the effect of Toxoplasma on the rat's reaction to 3 food-related novel stimuli (odour, food- container, food). A trappability study was performed on the other two groups to test whether Toxoplasma had an effect on probability of capture. The results show that low neophobia was significantly associated with positive Toxoplasma titres in 3 out of 4 groups. We suggest that differences between infected and uninfected wild rats arise from pathological changes caused by Toxoplasma cysts in the brains of infected rats. Such behavioural changes may be selectively advantageous for the parasite as they may render Toxoplasma-infected rats more susceptible to predation by domestic cats (the definitive host of Toxoplasma) and, as a side-effect, more susceptible to trapping and poisoning during pest control programmes.
The use of sheep fistulated at the oesophagus for the recovery of strongyloid larvae from pasture
Authors: Heath D. D. , Southcott W. H. , May P. F.
Published: June 2009

Estimates were made of the intake of strongyloid infective larvae by sheep at pasture by the recovery of larvae from samples of herbage collected through oesophageal fistulae.

All herbage eaten was not recovered through the fistula but few larvae were lost in the process of mastication and swallowing. More larvae could be recovered from macerated than from undamaged herbage.

Samples were obtained from different sheep on different days and at different times during the day and the variance components associated with these factors were estimated from seven sets of observations. The contribution to variance differed widely for each factor with the major contribution coming from time changes in the differences between sheep.

The authors wish to thank Mr G. W. Major for valuable technical assistance throughout these studies.
Transmission of Leucocytozoon sakharoffi in England by Simulium angustitarse
Authors: Baker J. R.
Published: June 2009

Leucocytozoon sakharoffi of English rooks (Corvus f. frugilegus) underwent sporogony in female Simulium (Eusimulium) angustitarse, the cycle taking 3–4 days. Sporozoites from the salivary glands of S. angustitarse, both naturally and experimentally infected, gave rise to L. sakharoffi infections when injected to aparasitaemic rooks, with a minimum pre-patent period of 8 days.

I am very grateful to the following persons, for invaluable help in many ways: Mr C. Swan and Mr A. Ponchaud (Ministry of Agriculture, Fisheries and Food); Dr J. Ash, Mr N. A. Wood and Mr M. Holland (Game Research Association); Mr N. A. Hancock (Smith, Kline and French); Mr N. Biddlecombe (Breamore Estate); Dr L. Davies (Durham University); Professor D. S. Bertram, Mr E. J. Blackie, Miss L. Selden, Miss J. Freeman and Mr P. Mellor (London School of Hygiene and Tropical Medicine).

This work was generously supported by a grant from the Natural Environment Research Council.
Cold tolerance of an endoparasitic nematode within a freezing-tolerant orthopteran host
Authors: Tyrrell C. , Wharton D. A. , Ramløv H. , Moller H.
Published: June 2009

Wetanemasp. is a nematode parasite of the hind gut of the freezing-tolerant orthopteranHemideina maori(a New Zealand alpine weta). The prevalence and intensity of infection remains high throughout the winter, suggesting that the parasite can survive despite the regular freezing of the host. In the laboratory,Wetanemahas survived freezing within its host to temperatures as low as −61 °C, much lower than the supercooling point or lower lethal temperature of the weta. The freezing tolerance of the parasite is therefore much greater than that of its host. Female worms survived lower temperatures better than males and juveniles. Parasites might assist the freezing tolerance of their host if they acted as endogenous ice nucleators. However, there was no relationship between the size of the worm burden and the supercooling point of the host and no significant difference between the supercooling points of infected and uninfected hosts. The freezing and subsequent survival of isolatedWetanemawas observed directly on a microscope cold stage. This parasite of a freezing- tolerant host is thus also freezing tolerant. There are few other reports of a parasite surviving freezing within a living host.
The use of biotin-labelled, synthetic DNA oligomers for the detection and identification of Plasmodium falciparum
Authors: Hughes M. A. , Hommel M. , Crampton J. M.
Published: June 2009

An oligonucleotide mixture based on the 21 base pair repeat sequence of Plasmodium falciparum was covalently coupled to biotin and used as a probe to detect P. falciparum DNA. The limit of detection was 10 ng. This method was further developed as a fingerprint assay for parasite strain typing. After restrictian enzyme digestion, blotting and hybridization, distinct banding patterns were obtained for the strains tested and these were reproducible. In addition, discrete differences were found between PLF-3 S + /S-strains which may implicate genetic reorganization in the switching mechanism which occurs when parasites are passed from an intact to a splenectomized animal.
Hymenolepis diminuta: an investigation of juvenile hormone titre, degradation and supplementation in the intermediate host, Tenebrio molitor
Authors: Hurd H. , Strambi C. , Beckage N. E.
Published: June 2009

Metacestodes of Hymenolepis diminuta cause a perturbance of vitellogenesis in the intermediate host Tenebrio molitor. The reduction in host reproductive output associated with infection may be due to this pathophysiology. Many of these events are regulated by host juvenile hormone (JH). A comparison of the titre of JH and its rate of degradation in female control and parasitized 15-day-old insects has been made. Haemolymph from female beetles contained 1·27 pMol JH equivalents/100 µl. No significant difference was associated with infection. However, topical application of a JH analogue, methoprene, at the time of infecion or 8 days post-infection reduced the significant accumulation of vitellogenin usually found in the haemolymph of females 12 days or more post-infection. These findings indicate that parasite-induced alteration of host vitellogenesis is not mediated via alteration in JH titres, although observations made after hormone supplementation suggest some form of interaction between the parasite and the host endocrine system.
Vaccination againstTrichinella spiralisin mice using antigens from different isolates
Authors: Goyal P. K. , Wakelin D.
Published: June 2009

Antigen preparations from three isolates ofTrichinella spiralis (sensu-stricto)have been tested for their ability to immunize mice against homologous and heterologous challenge infections. Immunization was measured by accelerated expulsion of adult worms, reduction in female worm fecundity, stunting of growth, and level of antibody responses before and after challenge. Antigens of two isolates, from London (L) and Poland (P), immunized effectively against homologous challenge, adult worm recoveries being reduced by 64% and 51% respectively within 6 days. Antigen from a Spanish(S) isolate gave no homologous protection in terms of worm recovery at day 6 and only 43% reduction at day 8. L- and P-isolate antigens immunized well against heterologous challenge (day 6 worm recoveries reduced by 66% and 59%) but similar protection against S-isolate challenge was not seen until day 8. Immunization with S antigen gave better protection at day 6 against L-isolate challenge (77%) than against challenge with P-isolate (37%). These results imply considerable, but not complete, antigen cross-reactivity between the isolates and this was reflected in antibody responses. These variations in immunogenicity and immunization potential are discussed in terms of constraints on the use of vaccines against parasites that are widely distributed geographically.
Labelling larvae of the cattle-tick Boophilus microplus, with 32P to follow their movements on the host
Authors: Kemp D. H. , Koudstall D. , Kerr J. D.
Published: June 2009

After 24 h desiccation at 28–29 °C and approximately 50 % relative humidity about 70 % of B. microplus larvae drank sufficient solution containing 1·5 mCi of 32P per ml for their movements on the host to be followed with a portable G-M counter. Reduced viability of the labelled ticks could not be detected when they were kept for 24 h on the host and either allowed to feed or prevented from doing so. When feeding was continued for 72 h or when larvae were incubated for 3–4 weeks, adverse effects were found, the severity of which could not be directly related to the amount of 32P label. Desiccation, handling of larvae and exposure to radiation in the drinking solution may have contributed to their reduced viability.

Since resistance to the tick is manifest within the first 24 h after infestation labelled larvae could be used to compare development on different hosts during this time. Even after feeding for 72 h, larvae were more adversely affected by host resistance than by labelling damage.

We would like to thank Mr C. A. Schuntner for helpful advice and Mrs J.Galligan for technical assistance. The financial support of the Australian Meat Research Committee is gratefully acknowledged. Messrs D. Hancox and S. R.Henderson assisted with some of the experiments.
Intracellular differentiation ofLeishmania amazonensispromastigotes to amastigotes: presence of megasomes, cysteine proteinase activity and susceptibility to leucine-methyl ester
Authors: Galvao-Quintao L. , Alfieri S. C. , Ryter A. , Rabinovitch M.
Published: June 2009

Intracellular differentiation ofLeishmaniapromastigotes to amastigotes is a critical step in the establishment of infection. In this report three related features ofmexicanasubspecies amastigotes were used to follow the differentiation of the parasites within macrophages. Early after infection, (a) parasites did not contain ultrastructurally recognizable megasomes, (b) cysteine proteinase activity of parasite lysates was not detected in gelatin-containing acrylamide gels, and (c) parasites were essentially resistant to L-leucine-methyl ester (Leu-OMe). Typical megasomes were first identified on the 5th day, were more prevalent on day 7, and underwent swelling in macrophages exposed to Leu-OMe. Cysteine proteinase activity was first detected on day 3 and increased thereafter. Susceptibility to Leu-OMe of parasites studiedin situor isolated from infected macrophages increased with time of intracellular residence and by 7 days approached that of amastigotes isolated from mouse lesions. In contrast, parasites derived from either promastigotes or amastigotes were equally susceptible to another leishmanicidal compound, tryptophanamide (Trp-NH2). The results provide additional support for the involvement of megasomes and their cysteine proteinases in parasite killing by Leu-OMe, and highlight the slow pace of the intracellular differentiation ofL. amazonensispromastigotes to amastigotes.
Capture and penetration processes of the free-living juveniles ofTrichostrongylus colubriformis(Nematoda) by the nematophagous fungus,Arthrobotrys oligospora
Authors: Murray D. S. , Wharton D. A.
Published: June 2009

The nematode-trapping fungusArthrobotrys oligosporatraps and invades all the free-living juvenile stages of the tri-chostrongyle nematodeTrichostrongylus colubriformis. The processes of capture and invasion of the 1st-stage juveniles are described using differential interference contrast optics and 3-D reconstruction techniques. The adhesive responsible for capture is well preserved using a freeze-substitution technique for scanning electron microscopy. The invasion process of the ensheathed 3rd-stage juvenile ofT. colubriformistakes much longer than in the 1st- or 2nd-stage juvenile and involves the formation of secondary infection pegs between the sheath and the cuticle which appear to penetrate the cuticle by physical pressure.
Histological changes in mosquito flight muscle fibres associated with parasitization by filarial larvae
Authors: Beckett Evelyn B.
Published: June 2009

1. Serial sections were examined of thoraces of a selected strain of Aedes aegypti infected with either Brugia pahangi or subperiodic B. malayi and of wild-caught Mansonia uniformis infected with the latter parasite.

2. A few badly damaged flight muscle fibres are seen in the early stages of infection but many more fibres are destroyed at the time when the mature filarial larvae leave the muscle and enter the haemocoel. In the intervening period, when the larvae are growing within the muscle fibres, only minor damage develops, affecting nuclei and/or mitochondria. The nature of such minor damage and the mechanism of complete muscle breakdown differs in the two species of mosquitoes.

3. It was concluded that the muscle damage was sufficiently severe to explain the significant mortality often observed among experimentally infected mosquitoes at the time when the mature filarial larvae enter the haemocoel.

I am very grateful to Dr W. W. Macdonald, of the Liverpool School of Tropical Medicine, who supplied the Aedes aegypti mosquitoes and who has given invaluable help and advice throughout this study. Mr Cheong Weng Hooi and his colleagues in Kuala Lumpur kindly supplied, and partly processed, the Mansonia uniformis mosquitoes. Miss M. A. Johnson assisted with the care of the A. aegypti colony and Mrs J. Oliver helped with some of the histological work.
Longitudinal studies of the immune response of Colombian patients infected with Trypanosoma cruzi and T. rangeli
Authors: Hudson L. , Guhl F. , de Sanchez N. , Bridge D. , Jaramillo C. A. , Young A.
Published: June 2009

Two groups of patients were examined for anti-Trypanosoma cruzi antibodies by immunofluorescence and ELISA (i) inhabitants of the village and surrounding rural area of Tibu, Norte de Santander, Colombia (n = 327) and (ii) employees of the Empresa Colombiana de Petroleos (ECOPETROL, n = 849). The latter group had a lower rate of positive serology (12 as compared to 29%) but the distributions of antibody titres were very similar in the two groups. A total of 119 serum samples (37 village and 82 ECOPETROL, including 25 seronegative controls) were analysed for their ability to immunoprecipitate the 7 major polypeptides of T. cruzi trypomastigotes of Mr > 72 kDa. Although 10 sera from positive patients showed no immunoprecipitation, all of the remaining positive sera contained antibodies which reacted with the 150, 90 and 85 kDa polypeptides. When the T. cruzi immunofluorescence positive, immunoprecipitation negative sera were retested by ELISA using GP90, all were negative thus suggesting that the patients had had a misdiagnosed T. rangeli infection. The new diagnosis was confirmed by immunofluorescence and ELISA with T. rangeli epimastigotes. Longitudinal studies were carried out on 19 patients from the ECOPETROL group for up to 3–5 years. Five seropositive patients showed a change in their anti-trypomastigote immunoprecipitation profiles over this period; one by loss of a previously recognized high molecular weight band and four others by conversion from a negative to a positive immunoprecipitation profile. These latter patients presented initially with uncomplicated T. rangeli infection but then acquired a T. cruzi superinfection. These patients represent the nucleus of a group in which prospective studies will identify the effect of T. rangeli infection on the course of subsequent South American trypanosomiasis and Chagas' disease.
Dynamics of infection in rats given low doses of homogonic and heterogonic Strongyloides ratti
Authors: Wilson P. A. G. , Simpson Norama E.
Published: June 2009

The results of control infections from 39 experiments using the ‘exact dose’ technique are analysed and compared with earlier large dose experiments with homogonic S. ratti. A smaller error variance and less added variance between experiments accompany the new method, which therefore provides a more precise experimental system. Using the exact dose technique, it is established that the migratory bahaviour of small numbers of L3 of the homogonic strain in lactating animals is the same as that of large numbers. In previous work the rate of migration of the homogonic strain estimated from conventional large dose experiments (Wilson, Cameron & Scott, 1978b) differed from that deduced from the use of radio-isotope labelled L3 (Wilson, 1979). ‘Exact dose’ data support results with the latter technique. There are significant differences between strains. The heterogonic larvae take longer to migrate in lactating hosts and appear to distribute themselves differently between mother and offspring. The consequences of these findings for theories of pathfinding in hosts are discussed. Experiments are also reported which failed to detect any artifact which might have resulted from ether anaesthesia of rats at injection of larval worms. This observation has implications for other studies in progress in this laboratory.
Haemonchus in India
Authors: Sood M. L.
Published: June 2009

Haemonchosis is an acute problem in India. Three species of Haemonchus occur. These are H. contortus (Rudolphi, 1803) which occurs in sheep, goat, cattle, buffalo and other ruminants; H. longistipes Railliet && Henry, 1909 occurring in camels and H. similis Travassos, 1941 in cattle. Seasonal fluctuation of H. contortus occurs, with infection being more frequent in autumn ≻ summer ≻ winter ≻ spring, and infection in sheep and goats has been reported to be 100 %. Various aspects of haemonchosis have been investigated. However, the fundamental and the most challenging areas in Haemonchus research remain almost untouched. In order
to forecast the development of haemonchosis, epidemiological studies should be undertaken on the prevalence, distribution and seasonal incidence of the worm to understand the effects of climatological factors like rainfall, humidity and temperature. The sparse and inadequate studies of metabolism need to be extended to other areas of Haemonchus biochemistry to provide additional possibilities for exploration of hostparasite differences. Clinical haemonchosis in sheep, goats and other
ruminants should be studied in order to calculate losses caused by mortality and the cost of anthelmintic medication. Most anthelmintics are expensive, and are not easily available to our farming community, therefore a search for many more indigenous anthelmintics (such as Wopell, Krimos, Sonex etc) must be made. Detailed knowledge of the mode of action and route of entry of anthelmintics at the molecular level could also be beneficial, particularly when the strains of H, contortus have been identified as resistant to some anthelmintics. The prospects of producing a vaccine against H. contortus should be explored. Attempts in this field have already been made by overseas workers (see Clegg && Smith, 1978) and in India too, work has been undertaken at Kerala (Sathianesan, personal communication). Therefore, because of its economic importance and wide distribution, H. contortus provides fascinating research material particularly in the warmer regions of the world.
The effects of the nematode peptide, KHEYLRFamide (AF2), on the somatic musculature of the parasitic nematode Ascaris suum
Authors: Pang F. Y. , Mason J. , Holden-Dye L. , Franks C. J. , Williams R. G. , Walker R. J.
Published: June 2009

AF2 is an endogenous RFamide-like peptide from the parasitic nematode Ascaris suum. The potent stimulatory effects of this peptide on the somatic musculature of Ascaris strongly suggest that it may have an important role in the motornervous system. Here we have investigated the possibility that AF2 may elicit a stimulatory action on Ascaris muscle by potentiating the actions of the excitatory cholinergic motornervous system either pre-synaptically, post-synaptically or both. In in vitro pharmacological experiments AF2 produced a dose-dependent increase in the frequency and amplitude of spontaneous contractions of Ascaris muscle strip which lasted for more than 1 h after a 3 min application of AF2 (10 nM–10µM; N = 7). In addition, AF2 (100 nM) potentiated the contraction elicited by ACh by 43 ± 9% (P < 0·01; N = 8). In electro-physiological recordings from muscle cells, AF2 (10–100 nM; N = 10) potentiated the amplitude of EJPs (excitatory junction potentials). For 100 nM AF2, the potentiation of the EJP was 218 ± 48% (N = 7; P < 0·01). This effect reversed after a wash of 10 min. AF2 did not potentiate the depolarization of the muscle cell elicited by bath applied ACh. These latter two observations are consistent with a presynaptic action of AF2. AF2 (10–100 nM) generated spontaneous muscle cell action potentials in previously quiescent cells. This effect took more than 1 h to wash out. These observations are discussed in terms of the paralysis of Ascaris that is elicited by AF2.
Q fever (Coxiella burnetii) reservoir in wild brown rat (Rattus norvegicus) populations in the UK
Authors: Webster J. P. , Lloyd G. , Macdonald D. W.
Published: June 2009

Seroprevalence ofCoxiella burnetii, the causal agent of Q fever in humans, was examined in wild brown rat populations from 4 Oxfordshire farmsteads (n= 127), 9 Somerset homesteads (n= 98), and 1 captive enclosure (n= 88) in the UK. Seroprevalence ranged between 7 and 53%, the lowest being within the captive population and the highest on dairy farmsteads with sheep present. This is the first reported investigation ofC. burnetiiin wild rats outside India. We suggest that the high Seroprevalence among rats (i) provides evidence that wild rats constitute an important reservoir forC. burnetiiin the UK, and (ii) explains why cats, as frequent predators of rats, are so important in the epidemiology of this disease.
Scanning electron microscopy of the tegument of adult Schistosoma curassoni, and comparison with male S. bovis and S. haematobium from Senegal
Authors: Southgate V. R. , Rollinson D. , Vercruysse J.
Published: June 2009

Scanning electron microscopical studies of adult male and female Schistosoma curassoni, male S. haematobium and male S. bovis are reported. The tubercles on the dorsal and dorso-lateral surfaces of male S. bovis are devoid of spines, whereas spines are present on the tubercles of male S. curassoni and S. haematobium. Some of the tubercles of S. curassoni and S. haematobium are completely covered in spines, whereas others have a spine-free apical area. Thus, on the isolates examined from Senegal it is concluded that adult male S. bovis can be easily distinguished from S. curassoni or S. haematobium on the basis of the structure of the tubercles. The surface of female S. curassoni is smooth, with transverse striations and a pitted appearance, apart from the posterior part where anteriorly pointing spines are found.
Antigenic characterization of adultWuchereria bancroftifilarial nematodes
Authors: Morgan T. M. , Sutanto Inge , Purnomo  , Sukartono  , Partono F. , Maizels R. M.
Published: June 2009

AdultWuchereria bancroftiwere recovered from infectedPresbytis cristatusmonkeys and radio-isotope labelled extrinsically with125I andin vitrowith [35S]methionine.125I labelling of the surface of adultW. bancroftipermitted a comparison between the major surface antigens of this species and those from the related lymphatic filariae,Brugia malayiandB. pahangi. All species bear a prominentMr29 000 surface antigen but among the differences observed were the strongly labelled molecules withMr58 000 and 67 000 inW. bancroftiwhich are extremely faint in theBrugiaspecies. The [35S]methionine label was effectively incorporated into somatic parasite proteinsin vitroalthough it was not possible to identify any secreted proteins in this way. The antigenicity of these products was investigated using a variety of sera from homologous and heterologous infections and the immunoprecipitation patterns highlighted particular differences between somatic proteins of male and female worms. One secreted antigen was detected, however, by virtue of its phosphorylcholine epitopes, in the culture medium of mixed adult worms; medium from maleW. bancroftiadults was negative although homogenates of either sex of adultW. bancroftiwere strongly positive in the same system.
Circulating antigen levels in serum of cattle naturally infected withSchistosoma mattheei
Authors: De Bont J. , Van Lieshout L. , Deelder A. M. , Ysebaert M. T. , Vercruysse J.
Published: June 2009

Levels of 2Schistosomacirculating antigens, the circulating anodic antigen (CAA) and the circulating cathodic antigen (CCA), were determined in serum samples collected, on a monthly basis over a period of 1·5 years, from 32 farm animals of different ages and from 12 tracer calves exposed toSchistosoma mattheeiinfection on a Zambian farm. Faecal egg counts were monitored in all animals and worm burdens in tracers determined after perfusion. Antigen determination tests in serum, with sensitivities between 95 and 100% in heifers and adult cows, proved to be excellent tools for the diagnosis of cattle schistosomiasis. Also in young calves, some infections could be demonstrated earlier by CCA determination than by faecal egg examination. A poor correlation was seen between the data for faecal egg counts and for CAA and CCA levels. It therefore appears that circulating antigen measurements in serum are of limited value as indicators of the pathogenesis of infection in cattle. Although all tracer calves were found infected at perfusion, large variations were recorded in antigen levels. An unexpected finding was the observation in farm animals of a clear seasonal pattern in CAA levels, with significant increase between August and October during the second half of the dry season, when animals are subjected to heavy physical and nutritional stress. It therefore appears that, although circulating antigen determination may provide an indication of the worm burden in ageing infections, possible variations of antigen clearance rate with the physiological condition of the host may complicate the interpretation of the results.
Studies on immunity toSchistosoma mansoni in vivo: whole-body irradiation has no effect on vaccine-induced resistance in mice
Authors: Vignali D. A. A. , Bickle Q. D. , Taylor M. G.
Published: June 2009

Actively immunized mice, whole-body irradiated with 650 or 525 rad., manifested comparable levels of resistance toSchistosoma mansonicompared with unirradiated, immunized mice in spite of a marked reduction in circulating leucocytes (>90%) and platelets (>85%), and despite an abrogation of delayed-type hypersensitivity (DTH) (Type IV) response to schistosomular antigens (as determined by footpad swelling, 24 h after injection of antigen). However, limited histopathological comparison of lung sections from irradiated and unirradiated mice 7 days post-challenge showed that cellular reactions (‘foci’) around parasites were essentially similar in size and cellular composition except that in irradiated mice, eosinophils were poorly represented both in the foci and in lung tissue in general. Neither presumed immune complex-mediated (Type III, Arthus reaction) hypersensitivity (as determined by footpad swelling, 5 h after injection of antigen) nor serum anti-schistosomulum extract antibody levels (as determined by ELISA) were affected. In addition, the pattern of125I-labelled schistosomular surface antigens immunoprecipitated with serum from irradiated and unirradiated mice was essentially similar. These results are consistent with antibody playing an important role in vaccine-induced immunity in mice but suggest that radiosensitive T cell function and radiosensitive cells, such as platelets and polymorphonuclear cells, including eosinophils, may not be essential.
Experimental and field studies on the viability of eggs, and the infectivity of third-stage larvae of the human hookworm Necator americanus recovered from the creek waters of the Niger Delta, Nigeria, and their epidemiological significance
Authors: Udonsi J. K.
Published: June 2009

In a combined field and laboratory study, the eggs and 3rd-stage infective larvae of the human hookworm Necator americanus were recovered from the creek waters of the Niger Delta, Nigeria. They were tested for viability and infectivity. Eggs recovered from fresh water creeks showed a viability or hatching index of between 17·5 and 23·7%. Eggs recovered from brackish water showed a viability index of 18·8–21·4% in ‘normal’ cultures, and a maximum index of 6·3% when cultured in brackish water. The differences in the viability indices of these eggs were not significant (P > 0·05). Infective 3rd-stage larvae were recovered from both fresh creek water (205–258 L3/litre of water), and brackish water (45 L3/litre of water). Larvae hatched from brackish water eggs that were cultured in the brackish water were 20% infective by 3 days, but lost all infective potential by 7 days posthatching. Larvae from fresh water eggs, cultured in fresh water and ‘normal’ laboratory cultures reached 50% infectivity in 3–5 days, losing potential infectivity in 11–15 days posthatching. The infectivity patterns of larvae recovered directly from fresh and brackish waters did not differ significantly (P > 0·05) from the infectivity patterns of larvae recovered from laboratory cultures of eggs from all the experimental sources. Although larvae recovered directly from fresh and brackish waters survived in these respective media under laboratory conditions, there was a significant difference (P < 0·05) in their survival patterns. The survival and infectivity rates of field larvae were considerably reduced over time relative to control larvae. These results indicate that both contaminated fresh and brackish water creeks and their banks may form additional hookworm infection foci in areas where various water contact activities are carried out by the human host population.
Observations on the epidemiology of coccidial infections in sheep under varying conditions of intensive husbandry including chemoprophylaxis with monensin
Authors: Gregory M. W. , Catchpole Janet , Joyner L. P. , Parker B. N. J.
Published: June 2009

Coccidiosis occurs sporadically in lambs at about 6 weeks of age when oocyst output is very high in healthy as well as in diseased lambs. These experiments were designed to throw light on the source of infection and to correlate oocyst output in lambs and ewes with performance in lambs. In two experiments, one indoors on deep litter the other in outdoor paddocks, oocyst output (of different coccidial species), body weight and clinical state of lambs were recorded weekly. Oocyst output in ewes was also recorded, starting 1–4 weeks before lambing. Monensin was included in the concentrates of ewes and/or lambs, up to lambing or before and after lambing. No periparturient rise was detected in the oocyst output of ewes. Monensin drastically reduced oocyst output in animals receiving it. Oocyst output in lambs appeared to be little affected by the output of ewes around the lambing period, but was reduced if the ewes' output was kept low after lambing. Lambs receiving monensin tended to produce drier faeces but their weight gain was not significantly greater than that of controls. Eimeria crandallis was the predominant species in the lambs, followed by E. ovinoidalis and E. ovina.
The relationship between the age of Schistosoma mansoni cercariae and their ability to penetrate and infect the mammalian host
Authors: Lawson J. Ruth , Wilson R. A.
Published: June 2009

The ability of the cercariae of Schistosoma mansoni to penetrate the tails of mice was shown to remain constant throughout their lives. However, their capacity to establish themselves and then reach maturity decreased as they aged. The abdominal route of penetration produced consistently higher maturation rates than the tail route. Significantly different maturation rates were obtained by modifying the standard tail infection technique. Evidence is presented that age-related mortality of schisto-somula occurs within 24 h of penetration and may be associated with the exhaustion of energy reserves during the penetration of the stratum corneum. The relationship of this age-related mortality to ‘mass mortality’ is discussed.
The moulting process and the phenomenon of intermoult growth in the filarial nematode Brugia pahangi
Authors: Howells R. E. , Blainey L. J.
Published: June 2009

The larvae of Brugia pahangi recovered from the jird have been shown to grow continuously between moults, their length increasing at least 5-fold during the 4th instar. This intermoult growth is achieved without an increase in the surface area of larvae. The cuticle of very early 4th and 5th-stage worms is highly folded and intermoult growth is accommodated by an expansion of surface annular folds. The major increases in the surface area of larvae occur only through ecdysis, with an 8-fold increase in the surface area being achieved at the 3rd moult. The growth curve of these worms is therefore sigmoidal but the surface area curve is stepped. The relationship between the cuticles of nematodes and insects is discussed
A note on the genus Hyalomma Koch in Palestine
Authors: Adler S. , Feldman-Muehsam B.
Published: June 2009

The determination of Hyalomma sp. is discussed. In the material examined from Palestine the genital aperture of the female, the cuticle in the proximity of the stigmata and the number of ‘tunnels’ in the anterior border of the scutum are characters which facilitate diagnosis.
The kinetics of the penetration of some representative anthelmintics and related compounds into Ascaris lumbricoides var. suis
Authors: Trim A. R.
Published: June 2009

1. The rate of penetration of some representative drugs into Ascaris lumbricoides var. suis has been measured.

2. The series of 4-n-alkyl resorcinols shows a typical homologous series effect.

3. l-Nicotine penetrates relatively slowly.

4. Its rate of penetration is greatly influenced by the extent of dissociation of its methyl pyrrolidine basic group.

5. The rate of penetration of nicotine is greatly accelerated in the presence of some surface active substances.

6. Chloroform is the most rapidly penetrating substance studied, and its penetration is not significantly influenced by the presence of proteins, carbohydrates and fats and their products of digestion.

7. An analysis of the experimental results shows that the outermost layer of the cuticle of Ascaris is probably the main barrier to penetration. It behaves as if it were a thin; homogeneous layer of lipoid.

8. The significance of these results in the study of anthelmintics is assessed.
The water-soluble vitamins of parasitic worms
Authors: Chance M. R. A. , Dirnhuber P.
Published: June 2009

While investigating the nutrition of parasitic helminthes it became possible to estimate the amounts of several members of the vitamin B complex in the parasites. Information on this point was required in order to obtain some idea of the composition of a satisfactoryin vitrodiet.
Researches on the intestinal Protozoa of monkeys and man
Authors: Dobell Clifford , Neal R. A. , Hoare Cecil A.
Published: June 2009

1. It has previously been shown [by Dobell] that, in cultures of strain K 28c, Entamoeba histolytica could be maintained indefinitely and made to pass through all the stages of its life history.

2. It was also demonstrated that all non-encysting strains of E. histolytica could be induced to encyst in vitro by substituting their concomitant bacterial flora by that of strain K 28c.

3. In order to ascertain what part each constituent of the bacterial flora of K 28c played in the life of E. histolytica, a detailed analysis of this flora was carried out. It was found to comprise eight aerobic organisms (mostly of the B. coli group) and six anaerobes.

4. The properties of individual species and varieties of bacteria were studied by adding them to cultures of the amoebae or by hatching the cysts of E. histolytica in media previously seeded with the bacteria to be tested.

5. With the same end in view two methods were devised for producing simplified strains of E. histolytica associated with from one to four species of bacteria only. By treating the cysts with acriflavine, the mixed flora could be freed of the aerobic organisms, leaving only the spores of the anaerobes. The spore-bearing anaerobes, in their turn, could be eliminated by treatment of the mixture with gentian violet. By using these methods it was possible to produce cultures of ‘synthetic’ strains of E. histolytica accompanied by any desired combination of bacteria, whose properties it was desired to investigate.

6. The results of the earlier experiments suggested that the essential constituent of the flora of K 28c was B. coli, all varieties of which appeared to promote growth, induce encystation and excystation, and generally favoured the completion of the life-cycle of the amoebae in vitro, whereas the anaerobic bacteria present in the strain appeared to be inactive as regards encystation.

7. However, later experiments have demonstrated conclusively that, although the aerobic bacteria individually induced the cysts of E. histolytica to hatch and supported the growth of the amoebae indefinitely, only one species—the anaerobe N5—was capable of promoting encystation. As regards the aerobic bacteria, their chief role is to provide the anaerobic conditions necessary for the growth of the amoebae with N5 in culture.
Spiral torsion in Taenia taeniaeformis (Batsch, 1786) caused by the knotting together of two worms
Authors: Rees Gwendolen
Published: June 2009

The larval stage of Taenia taeniaeformis, namely, Cysticercus taeniae-taeniaeformis, has recently been described by the writer (1951), a detailed account being given of the musculature and of the excretory and nervous systems of the scolex and strobila. In addition, some abnormalities in structure were noted, chief of which was the spiral torsion observed in some specimens and which involved the musculature, excretory and nervous systems of the strobila but not the surface layers. A search was then made for some adult specimens in order to find whether the same abnormality could be seen and to ascertain what the effect of such a torsion would be on the genitalia in the mature and gravid regions. Several adult specimens, from the intestine of a cat, were given to the writer by Mr L. E. Hughes, veterinary investigation officer. Unfortunately, none of these specimens showed the identical spiral torsion found in the larva, but two of them had become knotted together, presumably at an early stage, and were considerably distorted in the regions involved in the knot. This distortion was again of a spiral nature but involved the entire proglottid and not only the internal structures as was found in the type of spiral torsion common in the larval stage of this species. The condition was not merely a turning over of the strobila but an abnormal spiral growth brought about by the continued constriction on the body where the two worms were twisted around one another. So here again, in the adult stage, spiral torsion is evident but from a different cause and involving the whole of the relevant segments from the surface layers to all the contained organs.
On the synonymy of Marshallagia orientalis (Bhalerao, 1932) with Marshallagia marshalli and a record of its occurrence from the mountainous region of the punjab
Authors: Sarwar M. M.
Published: June 2009

In June 1946, one male and one female helminth of the species Marshallagia marshalli (Ransom, 1907) were collected from one of two goats (Capra sibirica), at Manali, which had been slaughtered soon after their arrival from Spiti (Kangra district, Punjab, India). The abomasa, small intestines, lungs and livers of both the animals were available for examination. The lungs, livers and small intestines did not yield any helminths, but one male and one female of Marshallagia marshalli, were collected from the abomasum of one goat, and a single male specimen of Haemonchus contortus was collected from the abomasum of the other goat.
The mites (Acarina: Analgesidae) living on or in the feathers of birds
Authors: Radford Charles D.
Published: June 2009

In 1950 the author published a paper entitled ‘The Mites (Acarina) parasitic on Mammals, Birds and Reptiles’ in which it was stated that the subject of feather mites (Analgesidae) was too big to be included in that work, and though they were parasitic throughout their life upon the host or in the quills of the feathers they should be made the subject of a separate paper.
Polyhedral virus diseases affecting the larvae of the privet hawk moth (Sphinx ligustri)
Authors: Smith Kenneth M. , Wyckoff R. W. G. , Xeros N.
Published: June 2009

During June 1951 a quantity of eggs of the privet hawk moth were obtained in Cambridge. On emergence from the egg it was noticed that a number of the young larvae had died, some immediately after emerging, others after a period of a few days. In some cases the young larvae died before they had got completely clear of the egg shell. Examination of these larvae showed that all had died of a polyhedral virus disease.
Welcome from the Society Presidents
Authors: Smith Dave , Johnson Cathy , Fitzgerald David
Published: June 2009

The Presidents of the Microscopy Society of America, the Microbeam Analysis Society and the International Metallographic Society invite you to join them in Richmond for the 2009 Microscopy & Microanalysis meeting. This EXPO issue of Microscopy and Microanalysis provides you with full details of the scientific meeting and its ancilliary events, as well as giving valuable information about the many vendors who will be exhibiting their products at the meeting. Attendance at the meeting will provide you with a useful snapshot of the diverse activities taking place across the many scientific disciplines that currently utilize microscopy and microanalysis.
Hypothiocyanous acid reactivity with low-molecular-mass and protein thiols: absolute rate constants and assessment of biological relevance
Authors: Skaff Ojia , Pattison David I. , Davies Michael J.
Published: June 2009

MPO (myeloperoxidase) catalyses the oxidation of chloride, bromide and thiocyanate by H2O2 to HOCl (hypochlorous acid), HOBr (hypobromous acid) and HOSCN (hypothiocyanous acid, also know as cyanosulfenic acid) respectively. Specificity constants indicate that thiocyanate, SCN−, is a major substrate for MPO. HOSCN is also a major oxidant generated by other peroxidases including salivary, gastric and eosinophil peroxidases. Whereas HOCl and HOBr are powerful oxidizing agents, HOSCN appears to be a less reactive, but more thiol-specific oxidant. Although it is established that HOSCN selectively targets thiols, absolute kinetic data for the reactions of thiols with HOSCN are absent from the literature. This study shows for the first time that the reactions of HOSCN with low-molecular-mass thiol residues occur with rate constants in the range from 7.3×103 M−1·s−1 (for N-acetyl-cysteine at pH 7.4) to 7.7×106 M−1·s−1 (for 5-thio-2-nitrobenzoic acid at pH 6.0). An inverse relationship between the rate of reaction and the pKa of the thiol group was observed. The rates of reaction of HOSCN with thiol-containing proteins were also investigated for four proteins (creatine kinase, BSA, β-lactoglobulin and β-L-crystallins). The values obtained for cysteine residues on these proteins are in the range 1×104– 7×104 M−1·s−1. These second-order rate constants indicate that HOSCN is a major mediator of thiol oxidation in biological systems exposed to peroxidase/H2O2 systems at (patho)physiological concentrations of halide and SCN− ions, and that HOSCN may play an important role in inflammation-induced oxidative damage.
Induction of germination in Myxococcus xanthus fruiting body spores
Authors: Elías Montserrat , Murillo Francisco J.
Published: June 2009

Myxococcus xanthus, when starved on a solid surface, undergoes a multicellular cycle of development that consists of fruiting and sporulation. Myxospore germination has been followed in CTT, a complex medium composed mainly of peptides, by monitoring the sequential disappearance of some characteristic spore properties. Loss of heat resistance, shortly after incubation was initiated, was followed by loss of resistance to SDS and finally, refractility and ovoid shape. Germination of a population of myxospores did not occur synchronously. However, in the presence of calcium, germination was activated, being more rapid and synchronous. Other spore activation treatments tested did not have the same stimulatory effect. We searched for specific nutrients or chemicals capable of inducing germination. Amino acids, unlike other potential carbon and energy sources for M. xanthus, or several sugars tested, were most effective in triggering germination. Continuous incubation in CTT and Casamino acids germinant solutions was not required for induction and completion of germination of a large proportion of spores in a population.
The relationships between leukotoxin production, growth rate and the bicarbonate concentration in a toxin-production-variable strain of Actinobacillus actinomycetemcomitans
Authors: Ohta Hiroyuki , Miyagi Atsushi , Kato Keijiro , Fukui Kazuhiro
Published: June 2009

Actinobacillus actinomycetemcomitans, a Gram-negative periodontopathic bacterium, produces a leukotoxin belonging to the RTX family. The production of leukotoxin varies greatly among different strains of this species. In this paper the effects of growth rate and bicarbonate on the leukotoxin production by a toxin-production-variable strain (301-b) during growth in a chemostat were examined. When the bacterium was grown in anaerobic fructose-limited chemostat cultures (pH 7.0 and 37 °) at dilution rates (D) ranging from 0.04 to 0.20 h−1 in the absence and presence of 10 mM bicarbonate, it produced leukotoxin as a cluster of two polypeptides (M
r 113000 and 120000) and complexed with nucleic acids on the bacterial cell surface. The relationship between leukotoxin production and specific growth rate was analysed by plotting the specific rate of leukotoxin production [q
LT, in μg (mg dry wt)−1 h−1] against D. The plots were approximated to the linear relationships q
LT 2.7D − 0.058 and q
LT − 9.3D − 0.407 without and with bicarbonate, respectively. These relationships suggest that the apparent leukotoxin production is a result of both growth-rate-dependent production and growth-rate-independent decomposition. The cellular leukotoxin level was also followed after the change from chemostat to batch culture in the same fermenter. In batch culture leukotoxin production stopped immediately and the cellular toxin level rapidly decreased, suggesting toxin decomposition. From the slopes of the approximated linear relationships between q
LT and D, a theoretical maximum leukotoxin yield (Y
LT) was estimated as 2.7 and 9.3 μg (mg dry wt)−1 in the absence and presence of 10 mM bicarbonate, respectively. The increased Y
LT value in the cultures containing bicarbonate indicated that the addition stimulated the efficiency of leukotoxin synthesis up to about threefold. Further increases of bicarbonate concentration to between 20 and 40 mM had no effect on the total leukotoxin production, but the amount of extracellular leukotoxin increased with higher bicarbonate concentrations.