Differences in virulence and oocyst shedding profiles in lambs experimentally infected with different isolates of Cryptosporidium parvum

A wide spectrum of disease severity associated with cryptosporidiosis has been described, ranging from asymptomatic to fatal in both human and animal hosts. The reasons for the variations in severity are likely to be multifactorial, involving environmental, host and parasite factors. This paper describes two experimental infection trials in lambs, a symptomatic host for the parasite, to investigate variation in the clinical manifestations following infection with two distinct isolates of Cryptosporidium parvum. In the first experiment, groups of naïve lambs were challenged with one of two isolates (CP1 or CP2) at ​< ​1 week of age, to test the effect of the isolates on disease outcome. In a second experiment one group of lambs challenged at < 1 week of age (CP1) was then re-challenged with the same isolate at 6 weeks of age (CP1), while a second group was challenged for the first time at 6 weeks of age (CP1). This experiment examined age-related disease symptoms, oocyst shedding and the effect of prior exposure to the parasite on a subsequent homologous challenge. The two isolates were associated with significant differences in the demeanour of the animals and in the numbers of oocysts shed in the faeces. There were also differences in the duration and severity of diarrhoea, though these were not significant. The age of the lamb, at the time of a primary challenge (<1 week or 6 weeks), also resulted in differences in clinical outcomes, with younger lambs showing more severe clinical disease than the older lambs (feeding profiles and presentation of diarrhoea), while older lambs showed virtually no signs of infection but still produced large numbers of oocysts

FLORAL BIOLOGY AND BREEDING SYSTEM OF STERCULIA-CHICHA ST HIL (STERCULIACEAE)

90473574

Phenological aspects of flowering and fruiting at the Ecological Station of Paulo de Faria-SP-Brazil

The present work was carried out at 'Estacao Ecologica de Paulo de Faria', north of the state of Sao Paulo, southeast of Brazil (19°55'-19°58'S and 49°31'-49°32'W). The flowering and fruiting phenology of trees, shrubs, and lianas species were observed from April 1993 to December 1995. The results were compaired with those surveyed at other forests from Sao Paulo state: Santa Genebra (Campinas). Serra do Japi (Jundiai) and lianas of Mata Atlantica. The majority of species of lianas flowered from January to April and trees and shrubs between September to December. The most intense frutification period occurred during May to August. Similarly to Santa Genebra, the flowering season at 'Estacao Ecologica de Paulo de Faria' started at the beginning of the wet season while frutification during the dryest period of the year. At Serra do Japi, the flowering and frutification occurred from the end of dry and beginning of the rainy season. Considering the liana at Mata Atlantica presented two peaks of flowering, while at 'Estacao Ecologica de Paulo de Faria' occurs only one. Regarding the fruiting phenology is similar for both area, most species producing fruits during the first semestre

Development And Cytology Of Pollen In Dahlstedtia Malme (leguminosae: Papilionoideae)

Microsporogenesis, chromosome number, meiotic behaviour and meiotic index were investigated in Dahlstedtia pinnata and D. pentaphylla, two legume species occurring largely in Brazil, in order to ascertain whether the pollen could limit fertilization events. Archesporial cells originate primary sporogenous and anther wall precursor cells, the tapetum is uniseriate, uninucleate and glandular. Tetrads are tetrahedric or decussate, and cytokinesis is of the simultaneous type. Mature pollen grains are tricolpate and bicellular. No abnormalities in microsporogenesis were found. In both species the chromosome number is n = 11, a number not reported previously. The base number for Dahlstedtia is also 11, because cytological observations include both species of Dahlstedtia. D. pentaphylla has a higher meiotic index and lower individual variation values, and it is considered meiotically stable. Its pollen grains do not limit fertilization. D. pinnata has a lower meiotic index, and the pollen is one of the factors which limit fertilization. Furthermore, D. pinnata has numerous adventitious shoots, which suggest that vegetative propagation is important in its reproductive process. © 2002 The Linnean Society of London.1384461471Alam, S., Sandal, P.C., Relationships among free amino acids in male-sterile and male-fertile sudan grass, Sorghum vulgare var. sudanense (1967) Bangladesh Journal of Botany, 1, pp. 199-204Audran, J.C., Bouillot, J., Sporoderm infrastructural and cytochemical modifications in cytoplasmic male sterile broad bean (Vicia faba L.) (1981) Acta Societatia Botanica Polonica, 50, pp. 223-226Bawa, K.S., Webb, C.J., Flower, fruit, and seed abortion in tropical forest trees: Implications go the evolution of paternal and maternal reproductive patterns (1984) American Journal of Botany, 71, pp. 736-751Bhandari, N.N., The microsporangium (1984) Embryology of angiosperms, pp. 53-121. , Johri, BM, ed. Berlin: Springer-VerlagBolkhovskikh, Z., Grif, V., Matvejeva, T., Zakharyeva, O., (1969) Chromosome numbers of flowering plants, , Botanical Institute, Academy of Sciences of the Soviet UnionCharlesworth, D., Evidence for pollen competition in plants and its relationships to fitness: A comment (1988) American Naturalist, 132, pp. 298-302Coelho, L.G.M., Battistin, A., Meiotic behaviour of Adesmia DC. (Leguminosae-Faboideae) species native to Rio Grande do Sul, Brazil (1998) Genetics and Molecular Biology, 21, pp. 403-406Ferguson, I.K., Skvarla, J.J., The pollen morphology of the subfamily Papilionoideae (Leguminosae) (1981) Advances in legume systematics, (PART 2), pp. 859-895. , Polhill RM, Raven PH, eds. Kew: Royal Botanic GardensFrankel, R., Izhar, S., Nitsen, J., The timing of callose activity and cytoplasmic male sterility in Petunia (1969) Biochemical Genetics, 3, pp. 451-455Geesink, R., (1984) Scala Milletiearum: A survey of the genera of the tribe Millettieae (Leguminosae - Papilionoideae), , Leiden: E. J. Brill & Leiden University Press (Leiden Botanical Series, 1)Gerlach, D., (1969) Botanische Mikrotechnik, , Stuttgart: Georg. Thieme VerlagGerrits, P.O., (1991) The application of glycol methacrylate in histotechnologysome fundamental principles, , Netherlands: Department of Anatomy and Embryology. State University, GroningenGibson, P.J., Diggle, P.K., Flower development and male sterility in Ocotea tenera (1998) International Journal of Plant Science, 159, pp. 405-417Goldblatt, P., Cytology and the phylogeny of Leguminosae (1981) Advances in legume systematics, (PART 2), pp. 427-463. , Polhill RM, Raven PH, eds. Kew: Royal Botanic GardensGoldblatt, P., Index to plant chromosome numbers, 1975-78 (1981) Monographs in Systematic Botany from the Missouri Botanical Garden, 4Goldblatt, P., Index to plant chromosome numbers, 1979-81 (1984) Monographs in Systematic Botany from the Missouri Botanical Garden, 8Goldblatt, P., Index to plant chromosome numbers, 1982-83 (1985) Monographs in Systematic Botany from the Missouri Botanical Garden, 13Goldblatt, P., Index to plant chromosome numbers, 1984-85 (1988) Monographs in Systematic Botany from the Missouri Botanical Garden, 23Goldblatt, P., Johnson, D.E., Index to plant chromosome numbers, 1986-87 (1990) Monographs in Systematic Botany from the Missouri Botanical Garden, 30, p. 90Goldblatt, P., Johnson, D.E., Index to plant chromosome numbers, 1988-89 (1991) Monographs in Systematic Botany from the Missouri Botanical Garden, 40Goldblatt, P., Johnson, D.E., Index to plant chromosome numbers, 1990-91 (1994) Monographs in Systematic Botany from the Missouri Botanical Garden, 51Goldblatt, P., Johnson, D.E., Index to plant chromosome numbers, 1992-94 (1997) Monographs in Systematic Botany from the Missouri Botanical Garden, 61Goldblatt, P., Johnson, D.E., Index to plant chromosome numbers, 1994-95 (1998) Monographs in Systematic Botany from the Missouri Botanical Garden, 69Goldenberg, R., Shepherd, G.J., Studies on the reproductive biology of Melastomataceae in 'cerrado' vegetation (1998) Plant Systematics and Evolution, 211, pp. 13-29Guerra, M., O uso do giemsa em citogenética vegetal - Comparação entre a coloração simples e o bandeamento (1983) Ciência e Cultura, 35, pp. 190-193Horner H.T., Jr., A comparative light and electron-microscopic study of microsporogenesis in male-fertile and cytoplasmic male-sterile sunflower (Helianthus annuus) (1977) American Journal of Botany, 64, pp. 745-759Ilarslan, H., Horner, H.T., Palmer, R.G., Genetics and cytology of a new male-sterile, female-fertile soybean mutant (1999) Crop Science, 39, pp. 58-63Izhar, S., Frankel, R., Mechanism of male-sterility in Petunia. I. The relationship between pH, callase activity in the anthers and the breakdown of microsporogenesis (1971) Theoretical Applied Genetics, 41, pp. 104-108Janzen, D.H., A note on optimal mate selection by plants (1977) American Naturalist, 11, pp. 365-371Johannsson, M.H., Stephenson, A.G., Effects of temperature during microsporogenesis on pollen performance in Cucurbita pepo L. (Cucurbitaceae) (1998) International Journal of Plant Science, 159, pp. 616-626Johansen, D.A., (1950) Plant embryology: embryogeny of Spermatophyta, , Waltham, MA: Chronica Botanica CoJohri, B.M., Ambegaokar, K.B., Srivastava, P.S., (1992) Comparative embryology of angiosperms, , Berlin: Springer-VerlagJoppa, L.R., McNeal, F.H., Walsh, J.R., Pollen and anther development in cytoplasmic male sterile wheat Triticum aestivum (1966) Crop Science, 6, pp. 296-297Karnovsky, M.J., A formaldehyde-glutaraldehyde fixative of high osmalarity for use in electron microscopy (1965) Journal of Cell Biology, 27, pp. 137A-138AKnox, R.B., The pollen grain (1984) Embryology of angiosperms, pp. 197-271. , Johri, BM, ed. Berlin: Springer-VerlagKronestedt-Robards, E.C., Rowley, J.R., Pollen grain development and tapetal changes in Strelitzia reginae (Strelitziaceae) (1989) American Journal of Botany, 76, pp. 856-870Loukides, C.A., Broadwater, A.H., Bedinger, P.A., Two new male-sterile mutants of Zea mays (Poaceae) with abnormal tapetal cell morphology (1995) American Journal of Botany, 82, pp. 1017-1023Love, R.A., (1949) Estudos Citológicos Preliminares de Trigos Riograndenses, , Circular 74, Secretaria da Agricultura do Rio Grande do Sul, Porto AlegreMedina, D.M., Conagin, C.H.T.M., (1964) Técnica citológica, , Publicação 2610. Instituto Agronômico, CampinasMoore, R.V., Index to plant chromosome numbers, 1967-71 (1973) Regnum Vegetabile, 90Moore, R.V., Index to plant chromosome numbers, 1972 (1974) Regnum Vegetabile, 91Moore, R.V., Index to plant chromosome numbers, 1973-74 (1977) Regnum Vegetabile, 96Niesenbaum, R.A., The effects of pollen load size and donor diversity on pollen performance, selective abortion, and progeny vigor in Mirabilis jalapa (Nyctaginaceae) (1999) American Journal of Botany, 86, pp. 261-268O'Brien, T.P., Feder, N., Mccully, M.E., Polychromatic staining of plant cell walls by Toluidine Blue O (1964) Protoplasma, 59, pp. 368-373Peel, M.D., Carman, Z.W.L., Wang, R.R.-C., Meiotic anomalies in hybrids between wheat and apomictic Elymus rectisetus (1997) Crop Science, 37, pp. 717-723Prakash, N., Some aspects of the life story of Callistemon citrinus (Curt) Skeels (1969) American Journal of Botany, 17, pp. 107-117Prakash, N., (1986) Methods in plant microtechnique, 2nd edn., , Armidale, NSW: The University of New EnglandPrakash, N., Embryology of the Leguminosae (1987) Advances in legume systematics, (PART 3), pp. 241-278. , Stirton CH, ed. Kew: Royal Botanic GardensSenff, M.I., Hickenbick, M.C.M., Paira, N.R., Cytogenetic studies in species of the genus Vigna Savi (Leguminosae-Papilionoideae) (1992) Revista Brasileira de Genética, 15, pp. 407-418Senff, M.I., Schifino-Wittmann, M.T., Paim, N.R., Cytogenetic studies of populations of Arachis, Desmodium and Vigna species (Leguminosae-Papilionoideae) from Rio Grande do Sul (1995) Revista Brasileira de Genética, 18, pp. 629-631Snow, A.A., Spira, T.P., Pollen-tube competition and male fitness in Hibiscus moscheutos (1996) Evolution, 50, pp. 1866-1870Stephenson, A.G., Flower and fruit abortion: Proximate causes and ultimate functions (1981) Annual Review of Ecology and Systematics, 12, pp. 253-279Teixeira, S.P., Gabrielli, A.C., Anatomia comparativa do eixo vegetativo em Dahlstedtia pinnata e D. pentaphylla (Leguminosae, Papilionoideae) (2000) Revista Brasileira de Botânica, 23, pp. 1-11Teixeira, S.P., Prakash, N., Ranga, N.T., Ovule and early seed development related to seed abortion in Dahlstedtia pinnata and D. pentaphylla (Leguminosae, Papilionoideae) (2001) Phytomorphology, 51, pp. 41-50Tucker, S., Floral ontogeny in Sophoreae (Leguminosae, Papilionoideae). 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Differences in virulence and oocyst shedding profiles in lambs experimentally infected with different isolates of Cryptosporidium parvum

A wide spectrum of disease severity associated with cryptosporidiosis has been described, ranging from asymptomatic to fatal in both human and animal hosts. The reasons for the variations in severity are likely to be multifactorial, involving environmental, host and parasite factors. This paper describes two experimental infection trials in lambs, a symptomatic host for the parasite, to investigate variation in the clinical manifestations following infection with two distinct isolates of Cryptosporidium parvum. In the first experiment, groups of naïve lambs were challenged with one of two isolates (CP1 or CP2) at ​< ​1 week of age, to test the effect of the isolates on disease outcome. In a second experiment one group of lambs challenged at < 1 week of age (CP1) was then re-challenged with the same isolate at 6 weeks of age (CP1), while a second group was challenged for the first time at 6 weeks of age (CP1). This experiment examined age-related disease symptoms, oocyst shedding and the effect of prior exposure to the parasite on a subsequent homologous challenge. The two isolates were associated with significant differences in the demeanour of the animals and in the numbers of oocysts shed in the faeces. There were also differences in the duration and severity of diarrhoea, though these were not significant. The age of the lamb, at the time of a primary challenge (<1 week or 6 weeks), also resulted in differences in clinical outcomes, with younger lambs showing more severe clinical disease than the older lambs (feeding profiles and presentation of diarrhoea), while older lambs showed virtually no signs of infection but still produced large numbers of oocysts