Oocyst counts in crossbred ewes under tree-crop plantation in the forest zone of Ghana

In this paper, the Eimeria oocyst output of two groups, pregnant ewes (group 1) and non-pregnant controls (group 2), which were followed from September 1993 to August 1994, is described. In both groups of animals the level of oocyst output was high during the minor rainy season. However, during the periparturient period the pregnant ewes showed the higher oocyst output. The oocyst output in both group fell to similar levels after weaning of the lambs in March 1994. The species of Eimeria identified in order of dominance were Eimeria parva, E. pallida, E. faurei, E. ahsata, E. ovina, E. intricata, E. granulosa and E. ninakohlyakimovae. There were no differences in the species composition of oocysts in both groups of animals.     

Satellite DNA and heterochromatin of the flour beetle Tribolium confusum

The chromosomes of Tribolium confusum have conspicuous bulks of pericentromeric constitutive heterochromatin. The amount of heterochromatin measured by C-banding in metaphase chromosomes is estimated to be 40-45%. It is composed of an A + T rich DNA according to the distamycin A/diamidinophenylindol staining of chromosomes. Restriction analysis of isolated T. confusum genomic DNA shows that this species has a satellite DNA that constitutes about 40% of the genome. Cloning and sequencing experiments reveal a monomer length of 158 base pairs and a copy number of 5.77 x 10(5) per haploid genome. Its sequence is A + T rich (73%), with direct and inverted repeats, one of them with a possibility of forming stable cruciform structure. The abundance, monomer length, and the mutation rate are similar to those found in other satellite families from different species of Tenebrionidae, but no sequence homology has been found among them. No retarded mobility of satellite DNA, characteristic for molecules with sequence-induced curvature, has been detected by electrophoresis on nondenaturing polyacrylamide gels. In situ digestions with restriction enzymes and in situ hybridization show that this satellite DNA is located in pericentromeric positions of all chromosomes coinciding with C-bands.     

Eimeria from bats of the world: two new species from Myotis spp. (Chiroptera: Vespertilionidae)

Between 1986 and 1995, 548 fecal samples were collected from 41 species of bats (Molossidae, Mormoopidae, Phyllostomidae, Thyropteridae, and Vespertilionidae) from New Mexico, California, Baja California Sur (Mexico), and Bolivia. Of these, the feces of 28 (5%) bats, including Antrozous pallidus, Myotis ciliolabrum, Myotis lucifugus, and Myotis yumanensis (Vespertilionidae), contained oocysts representing at least 3 species of Eimeria. A new species of eimerian from M. lucifugus (3/27, 11%) and M. yumanensis (8/70, 11%) is described. Sporulated oocysts are ellipsoidal, 22.3 x 14.8 (18-25 x 13-16) microns with micropyle (approximately 2 microns) and polar granules (1-4), but an oocyst residuum is absent. The oocyst wall is slightly rough exteriorly and has 2 layers (total < or = 1 micron thick). Football-shaped sporocysts are 8.1 x 6.6 (8-11 x 5-7) microns, each with a Stieda body and granular sporocyst residuum present. A new eimerian from M. yumanensis (4/70, 6%) and M. ciliolabrum (1/12, 8%) also is described. Sporulated oocysts are spheroidal to subspheroidal, 15.0 x 14.1 (14-16 x 14-16) microns, with micropyle and oocyst residuum absent; a polar granule is present. The wall is smooth and has 2 layers (total < 1 micron thick). Sporocysts are football-shaped, 7.1 x 5.9 (6-9 x 5-7) microns, each with a Stieda body and sporocyst residuum. The sporulated oocysts of a third morphotype, found in A. pallidus (12/85, 14%), were indistinguishable from those of Eimeria arizonensis, a species typically found in murid rodents. The currently recognized species of bat Eimeria are listed, and a dichotomous key is provided.     

Temperature dependence of metabolic processes in perfused rat liver (author''s transl)

The ruthenium red (RR) stained forelimb musculature of three species of urodeles Triturus (Notophthalmus) viridescens, Amblystoma maculatum, Amblystoma opacum in various stages of growth were examined with the electron microscope for the presence of satellite cells. It was found that RR staining facilitated greatly the identification of satellite cells. In young larvae of all three species satellite cells were detected with a frequency of 29% to 48% per total number of nuclei. In adult Triturus and Amblystoma maculatum satellite cells were no longer detected; instead "pericytes" as described by Hay ('74) were seen with a frequency of 12% and 3% respectively. During metamorphosis of Triturus satellite cells, with part of their myofiber-satellite cell intercellular space filled with basement membrane material, occurred at a peak frequency. The cells presumably are intermediate in the formation of "pericytes." At ten days after metamorphosis satellite cells and intermediate cells were no longer detected and the limb musculature contained only "pericytes" similar to the ones observed in adult newts. The significance of the presence of satellite cells in relation to limb regeneration and muscle regeneration is discussed.     

Expression of myosin heavy chain and of myogenic regulatory factor genes in fast or slow rabbit muscle satellite cell cultures

We investigated the myogenic properties of rabbit fast or slow muscle satellite cells during their differentiation in culture, with a particular attention to the expression of myosin heavy chain and myogenic regulatory factor genes. Satellite cells were isolated from Semimembranosus proprius (slow-twitch muscle; 100% type I fibres) and Semimembranosus accessorius (fast-twitch muscle; almost 100% type II fibres) muscles of 3-month-old rabbits. Satellite cells in culture possess different behaviours according to their origin. Cells isolated from slow muscle proliferate faster, fuse earlier into more numerous myotubes and mature more rapidly into striated contractile fibres than do cells isolated from fast muscle. This pattern of proliferation and differentiation is also seen in the expression of myogenic regulatory factor genes. Myf5 is detected in both fast or slow 6-day-old cell cultures, when satellite cells are in the exponential stage of proliferation. MyoD and myogenin are subsequently detected in slow satellite cell cultures, but their expression in fast cell cultures is delayed by 2 and 4 days respectively. MRF4 is detected in both types of cultures when they contain striated and contractile myofibres. Muscle-specific myosin heavy chains are expressed earlier in slow satellite cell cultures. No adult myosin heavy chain isoforms are detected in fast cell cultures for 13 days, whereas cultures from slow cells express neonatal, adult slow and adult fast myosin heavy chain isoforms at that time. In both fast and slow satellite cell cultures containing striated contractile fibres, neonatal and adult myosin heavy chain isoforms are coexpressed. However, cultures made from satellite cells derived from slow muscles express the slow myosin heavy chain isoform, in addition to the neonatal and the fast isoforms. These results are further supported by the expression of the mRNA encoding the adult myosin heavy chain isoforms. These data provide further evidence for the existence of satellite cell diversity between two rabbit muscles of different fibre-type composition, and also suggest the existence of differently preprogrammed satellite cells.     

Hydrophobic and electrostatic cell surface properties of Cryptosporidium parvum

The oocyst wall of Eimeria spp. consists of a 10-nm-thick outer lipid layer and a 90-mm-thick inner layer of glycoprotein which has been described previously to be composed of a single major protein. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions and (125)I labelling of a oocyst wall fragments and of delipidated intact oocysts revealed a molecule of approximately 12 kDa as the major protein component of the oocyst wall of Eimeria tenella. An immunoglobulin M monoclonal antibody (c11B9F3) was produced against this 12-kDa oocyst wall protein sliced from a preparative SDS-polyacrylamide gel. Its reactivity by immunofluorescence against oocyst wall fragments and sporozoites or by immunoperoxidase assays of infected tissue sections was stage restricted to gametocytes and oocysts but pan-specific against all face of the oocyst wall. In chicks passively immunized with C11B9F3, oocyst output was significantly (P<0.01) reduced by 42 to 54% after homologous E. tenella infection and by 35% after heterologous Eimeria maxima infection compared with that of control groups. The results demonstrate the presence of a highly conserved, low-molecular-weight antigen on the oocyst wall and the gametocytes of Eimeria spp. which is a candidate for inclusion in a pan-specific, transmission-blocking vaccine against avian coccidiosis.     

IL-4 protects adult C57BL/6 mice from prolonged Cryptosporidium parvum infection: analysis of CD4+alpha beta+IFN-gamma+ and CD4+alpha beta+IL-4+ lymphocytes in gut-associated lymphoid tissue during resolution of infection

Resistance of adult C57BL/6 mice to severe Cryptosporidium parvum infection is dependent on CD4+alpha beta+ TCR lymphocytes. In this study, we demonstrated that treatment with anti-IFN-gamma mAb extended oocyst excretion 18 days longer, and anti-IL-4 mAb extended oocyst excretion at least 11 days longer than isotype control mAb treatment. Analysis of the specific activity of anti-IFN-gamma mAb present in treated mouse sera suggested that IFN-gamma may have a limited role in the resolution phase of infection. Changes were also documented in numbers of CD4+alpha beta+IFN-gamma+ and CD4+alpha beta+IL-4+ lymphocytes in Peyer's patches and intraepithelium of adult C57BL/6 mice during resolution of C. parvum infection. Resistance to initial severe infection was associated with CD4+alpha beta+IFN-gamma+ lymphocytes, and eventual resolution of infection was associated with CD4+alpha beta+IL-4+ lymphocytes. Analysis of cytokine expression following in vitro stimulation with C. parvum Ags during resolution of infection demonstrated consistent increases in CD4+alpha beta+IL-4+ lymphocytes, but not CD4+alpha beta+IFN-gamma+ lymphocytes. The relevance of CD4+alpha beta+IL-4+ lymphocytes in protection against C. parvum was then evaluated in C57BL/6 IL-4 gene knockout mice (IL-4(-/-)). Adult IL-4(-/-) mice excreted oocysts in feces approximately 23 days longer than IL-4(+/+) mice. Further, anti-IFN-gamma mAb treatment increased the severity and the duration of infection in IL-4(-/-) mice compared with those in IL-4(+/+) mice. Together, the data demonstrated that IFN-gamma was important in the control of severity of infection, and either IFN-gamma or IL-4 accelerated termination of infection. However, neither IL-4 nor IFN-gamma was required for the final clearance of infection from the intestinal tract of adult mice.     

Bacterial population dynamics in three anopheline species: the impact on Plasmodium sporogonic development

The functional role of bacteria in the midgut of adult mosquitoes is unknown. In this study, we examined the population dynamics of midgut bacteria of laboratory reared Anopheles stephensi, An. gambiae, and An. albimanus. Mosquito midguts were dissected under sterile conditions and examined for the presence of bacteria using standard microbiologic techniques. Ninety percent and 73% (n = 30) of newly emerged An. gambiae and An. stephensi, respectively, harbored bacteria. In contrast, only 17% (n = 23) of An. albimanus harbored any bacteria. The bacterial population increased 11-40-fold in the presence of a blood meal, but then decreased to pre-blood meal levels in 3-5 days. Pseudomonas cepacia, Enterobacter agglomerans, and Flavobacterium spp. were found in all three anopheline species. Midgut bacteria were acquired both transtadially and through the sugar meal. Transtadial transmission was demonstrated by successfully passaging Escherichia coli HS5 from the larval to the adult stage. However, midgut bacteria were acquired more efficiently through the sugar meal than through transtadial passage. An increase in midgut bacterial counts after mosquitoes were exposed to a bacteria/sugar suspension significantly reduced oocyst infection rates and densities in Plasmodium falciparum-infected mosquito cohorts. Since bacteria occur naturally in wild mosquitoes, it may be possible to modify anopheline vector competence using introduced or indigenous bacteria.     

Activation of latent HIV-1 by Mycobacterium tuberculosis and its purified protein derivative in alveolar macrophages from HIV-infected individuals in vitro

A chromosome-specific satellite DNA from the South American fish species Leporinus obtusidens has been isolated and characterized. Sequence analysis and Southern hybridization studies indicate that the cloned 483-bp fragment is 60% AT rich and appears to comprise two diverged monomers. A highly variable low-copy number polymorphism was detected and, thus, this satellite DNA may serve as a valuable genetic marker. Using a Southern blot approach, the cloned satellite DNA cross-hybridized strongly to the DNA of Leporinus elongatus but failed to detect homologous sequences in the genomes of other closely related Leporinus species and higher vertebrates. Using fluorescence in situ hybridization to mitotic metaphase spreads of L. obtusidens and L. elongatus, this satellite DNA was located to the (peri)centromeric region of one single chromosome pair in both species. As the cloned satellite DNA sequence clearly evolved along a chromosomal lineage and is highly variable, it may serve as a very useful marker in further genetic, molecular and cytogenetic studies of the genus Leporinus.     

Prevention of nausea and vomiting in female patients undergoing breast surgery: a comparison with granisetron, droperidol, metoclopramide and placebo

Centromerically located alphoid satellite DNAs are present in all primates. They typically consist of arrays of a 340-bp monomeric unit that is composed of related, but diverged, 170-bp subunits. A unique monomeric unit has recently been described: the alphoid satellite monomers of the neotropical primate Chiropotes satanas (bearded saki) are typically 539 bp in length. In addition, a number of smaller satellite sequences are present in this species. Analysis of two primates closely related to Chiropotes, Pithecia irrorata (saki) and Cacajao melanocephalus (uakari), show that they also contain unique alphoid satellites that are different from those of Chiropotes and different from one another. Southern blot and sequence analyses suggest that an alphoid satellite rearrangement(s) occurred early in the history of the tribe Pitheciini (Chiropotes, Pithecia, Cacajao) and that rearrangements are continuing to occur in this group of primates.     

Enzyme-linked immunosorbent assay for the detection of Cryptosporidium parvum IgG in the serum of cats

The objective was to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of Cryptosporidium parvum IgG in the serum of cats. The ELISA was an indirect ELISA using soluble C. parvum oocyst antigens and a peroxidase-labeled anti-feline IgG secondary antibody. Sera from cats with Toxocara felis, Giardia spp., Aelurostrongylus abstrusus, Isospora felis, Isospora rivolta, Toxoplasma gondii, or Taenia spp. infections were assayed in specificity studies. Following optimization, the ELISA and fecal examination for oocysts were performed on samples from 170 client-owned or humane society source cats and 1 cat inoculated orally with C. parvum oocysts. Cryptosporidium parvum oocysts were detected in feces (4/170; 2.4%), and C. parvum IgG was detected in serum (26/170; 15.3%) from naturally exposed cats. The seroprevalence data suggest that some cats in the geographical area studied were exposed to C. parvum, but persistent oocyst shedding was less common. The ELISA is not useful for predicting oocyst shedding in individual cats.     

Recent management of pituitary adenomas

Eight 2-day-old SPF chickens were each inoculated orally with a single dose of 5 x 10(5) oocysts of Cryptosporidium baileyi, and immunoglobulin G (IgG) antibody responses were chronologically measured by indirect immunofluorescent antibody (IFA) assay. Anti-C. baileyi IgG antibody levels remained high (1:106.67 to 1:512.00) for at least 4 months with 330 days of a detectable period. Ten days after the negative conversion, each chicken was re-challenged with 1 x 10(7) oocysts of the same species. Subsequent infection in 340-day-old individuals caused sudden elevated IgG antibody levels and the titer peaked on day 28 postchallenge inoculation (PCI), at 1:1.024 with a 65 days of detection period. Chickens in primary infection showed oocyst shedding profiles, but did not exhibit any oocyst shedding before or after experimental reinfection.     

Monitoring the abundance of Aedes (Ochlerotatus) albifasciatus (Macquart 1838) (Diptera: Culicidae) to the south of Mar Chiquita Lake, central Argentina, with the aid of remote sensing

Surges in the size of adult populations of the flood-water mosquito Aedes albifasciatus can produce important economical losses because of the way this species irritates livestock. Although this species is also the main vector of west equine encephalitis in Argentina, little is known about the factors affecting its population dynamics, as it is difficult to obtain data on its abundance over a large area. However, the results of intensive study of the mosquito in a few sites might reasonably be extrapolated to a regional scale by the use of remotely sensed data. The adult, larval and pupal stages of Ae. albifasciatus were sampled at five field sites to the south of Mar Chiquita Lake, either once a month (during the dry, cold season) or once a fortnight (during the warm, rainy season), between August 1992 and April 1993. The measured abundance of adults or pre-adults and a meteorological coefficient useful for the estimation of larval abundance each showed significant correlation with various statistics derived from normalized-difference, vegetation indices (NDVI) calculated from satellite (NOAA-AVHRR) imagery. A linear discriminant analysis, using data on NDVI, rainfall and temperature, accurately identified periods with and without pre-adults. The satellite imagery was also useful in the estimation of larval abundance and consequently could be used to predict adult abundance 7 days in advance. Even though the satellite data employed have poor spatial resolution, their high temporal resolution makes them very useful in studies of the population dynamics of mosquitoes in general, at least once the relevant variables and their relationships with mosquito breeding and survival have been identified.     

Two new coccidian parasites from the grand anglehead lizard, Gonocephalus grandis from Peninsular Malaysia

During 3 collecting expeditions between October 1996 and December 1996, fecal samples were obtained from 43 adult Gonocephalus grandis from Tanah Rata and the Cameron Highlands in Peninsular Malaysia. Two species of coccidia (Isospora gonocephali n. sp. [9/43, 23%] and Eimeria cameronensis n. sp. [3/43, 7%]) were discovered. Sporulated oocysts of I. gonocephali are subspherical to ovoidal, 22.3 x 18.7 (19-25 x 17-23) microm with a bilayered wall composed of a thin inner wall and a striated outer wall with a pitted surface; oocyst residuum absent; 1 polar granule present; sporocysts are almond-shaped, 13.5 x 9.2 (12-15 x 8.5-10) microm, Stieda body broad, domelike, substieda body fanlike, sporocyst residuum consisting of coarse, nonuniform granules in an amorphous cluster; sporozoites sausage-shaped with 1 large terminal, refractile body and lay randomly in the sporocyst. Sporulated oocysts of E. cameronensis are bilayered, smooth-walled, ellipsoidal, 26.5 x 12.4 (25-28 x 12-13) microm; with 1, small, polar granule composed of 2-3 splinter-like structures fused together; oocyst residuum absent; sporocysts ovoidal, almost rectangular-shaped 8.8 x 6.6 (8-9 x 5-7) microm, with no Stieda or substieda bodies, containing scattered residuum and 2 sausage-shaped sporozoites with 1 terminal, ovoidal refractile body. No individual lizard was host to both coccidian species.     

Coccidial infections of goats in Selangor, peninsular Malaysia

Coccidial infections were studied in goats in the state of Selangor (peninsular Malaysia) during a 12-month period. The study included 10 smallholder farms on which kids were monitored for faecal oocyst counts from birth until 1-year old. Eimeria oocysts were found in 725 (89%) of 815 faecal samples examined. Nine species of Eimeria were identified. The most prevalent were E. arloingi, found in 71% of the samples, E. ninakohlyakimovae (67%), E. christenseni (63%) and E. alijevi (61%). The other species found were, E. hirci, E. jolchijevi, E. caprovina, E. caprina and E. pallida, present in 34, 22, 12, 9 and 4% of the samples, respectively. Oocyst counts were significantly higher in animals of less than 4-months old (P < 0.05). High oocyst counts were mainly caused by non-pathogenic species. Poor hygienic conditions were found to be associated with a higher intensity of coccidial infections. Mortality rates in kids could not be related to the intensity of coccidial infections.     

Pair-rule and gap gene mutants in the flour beetle Tribolium castaneum

Early pattern formation in the Drosophila embryo occurs in a syncytial blastoderm where communication between nuclei is unimpeded by cell walls. During the development of other insects, similar gene expression patterns are generated in a cellular environment. In Tribolium, for instance, pair-rule stripes are transiently expressed near the posterior end of the growing germ band. To elucidate how pattern formation in such a situation deviates from that of Drosophila, functional data about the genes involved are essential. In a genetic screen for Tribolium mutants affecting the larval cuticle pattern, we isolated 4 mutants (from a total of 30) which disrupt segmentation in the thorax and abdomen. Two of these mutants display clear pair-rule phenotypes. This demonstrates that not only the expression, but also the function of pair-rule genes in this short-germ insect is in principle similar to Drosophila. The other two mutants appear to identify gap genes. They provide the first evidence for the involvement of gap genes in abdominal segmentation of short-germ embryos. However, significant differences between the phenotypes of these mutants and those of known Drosophila gap mutants exist which indicates that evolutionary changes occurred in either the regulation or action of these genes.     

Species differences in vasopressin receptor binding are evident early in development: comparative anatomic studies in prairie and montane voles

Monogamous prairie voles (Microtus ochrogaster) and promiscuous montane voles (Microtus montanus) exhibit remarkable differences in the distribution of vasopressin (AVP) receptors in the adult brain. This difference in receptor distribution is associated with species differences in the behaviors, including pair bond formation and paternal care, found selectively in the monogamous vole. To investigate a potential mechanism for this species difference in AVP receptors, the present study examined the ontogeny of receptor binding in the two species to determine whether the adult maps arose from a shared pattern in development. By using 125I-linear-AVP, which is a selective high-affinity ligand for the V1a receptor, we found early appearance and transient expression of AVP receptor binding during postnatal development in both species. However, the ontogenetic patterns of regional AVP receptor binding were species specific. In the diagonal band, the bed nucleus of the stria terminalis, and the central nucleus of the amygdala, prairie voles had higher AVP receptor binding at birth than montane voles, and this difference persisted with little variation into adulthood. In these areas, therefore, species differences in AVP receptor binding appeared to be determined primarily by genetic or prenatal factors. In the lateral septum, both species had low levels of AVP receptor binding at birth. Thereafter, the binding increased rapidly in montane voles, but it remained unchanged in prairie voles. In the cingulate cortex, AVP receptor binding in prairie voles showed a peak in early development with a subsequent decline and reached the adult level at weaning, whereas the binding in montane voles remained unchanged into adulthood. A similar but opposite pattern was found in the frontoparietal cortex, in which AVP receptor binding showed an early peak in montane voles but did not change significantly in prairie voles. These results demonstrate that 1) species differences in regional AVP receptor binding are evident in the early postnatal period and, in several areas, may be determined by genetic or prenatal factors, and 2) AVP may target brain areas differently in infant and adult prairie and montane voles and, thus, could exert differential effects on the organization of the central nervous system in the two species of voles.     

Use of live oocyst vaccines in the control of avian coccidiosis: experimental studies and field trials

Areas addressed in this study on the use of live oocyst vaccines to control coccidiosis include: the influence of immunocompetency of the strains and sex of the birds used; methods of delivery of vaccine; immunological variation between different strains of the same coccidial species; and the effects of combining vaccine with anticoccidial medication. The results show that vaccination with live oocysts elicited significant protection against coccidiosis, both with experimentally induced and naturally acquired coccidial infection, resulting in average bird weight gains and feed efficiency similar to that obtained with conventional anticoccidial medication.