RESUMO
PREMISE OF THE STUDY: Teosinte species are the closest relatives of maize and represent an important but increasingly rare genetic resource for maize improvement and the study of evolution by domestication. Three morphologically and ecologically distinct teosinte populations were recently discovered in México. The taxonomic status of these rare and endangered populations was investigated by detailed comparisons to previously characterized wild Zea species. ⢠METHODS: Three new teosinte populations were compared to known teosinte taxa on the basis of morphological, ecogeographic, cytological, and molecular characteristics. Phenetic and phylogenetic analyses were performed using morphological and molecular data, respectively. ⢠KEY RESULTS: The newly discovered populations are distinct from each other and from other Zea species to represent three new entities based on their unique combinations of morphological, ecological, ploidy, and DNA markers. A perennial diploid population from Nayarit is distinguished by early maturing plants, and having male inflorescences with few tassel branches and long spikelets. A perennial tetraploid population from Michoacán is characterized by tall and late maturing plants, and having male inflorescences with many branches. An annual diploid population from Oaxaca is characterized by having male inflorescences with fewer branches and longer spikelets than those found in the sister taxa Z. luxurians and Z. nicaraguensis, plants with high thermal requirements, and very long seed dormancy. ⢠CONCLUSIONS: Evidence from multiple independent sources suggests placement of the three new populations of teosinte as distinct entities within section Luxuriantes of the genus Zea. However, more extensive DNA marker or sequence data are required to resolve the taxonomy of this genus.
Assuntos
Zea mays/classificação , Cromossomos de Plantas , Marcadores Genéticos , México , Filogenia , Zea mays/genéticaRESUMO
We evaluated immunity to Haemophilus influenzae type b (Hib) in 18 human immunodeficiency virus-infected infants who were vaccinated with a complete series of Hib conjugate vaccine. Four months after the primary series, the geometric mean anticapsular antibody concentration in 11 children was 0.40 microgram/ml. There were no significant differences in CD4+ cell counts or in the Centers for Disease Control and Prevention disease classification according to the presence of immunity to Hib. Four months after the booster dose, the geometric mean anticapsular antibody concentration in the 18 children was 0.82 microgram/ml. Children with immunity were more likely than children lacking immunity to have higher CD4+ cell counts and mild human immunodeficiency virus-related disease. The majority of the anticapsular antibody concentrations were lower than in healthy children.
Assuntos
Anticorpos Antibacterianos/sangue , Proteínas de Bactérias , Infecções por HIV/imunologia , Infecções por Haemophilus/prevenção & controle , Vacinas Anti-Haemophilus , Haemophilus influenzae/imunologia , Vacinação , Vacinas Sintéticas , Proteínas de Bactérias/administração & dosagem , Proteínas de Bactérias/imunologia , Contagem de Linfócito CD4 , Infecções por HIV/complicações , Infecções por Haemophilus/imunologia , Vacinas Anti-Haemophilus/administração & dosagem , Vacinas Anti-Haemophilus/imunologia , Humanos , Imunização Secundária , Lactente , Estudos Prospectivos , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologiaRESUMO
We studied immunity to Haemophilus influenzae type b (Hib) polysaccharide capsule in 19 children infected with human immunodeficiency virus (HIV) immunized with a single dose of a Hib vaccine at a mean age of 28 months (range, 15 to 56 months). Four to eighty-five months after immunization, only 7 children (37%) were immune. There were no significant differences in the HIV classification of the Centers for Disease Control and Prevention, type of conjugate vaccine, age at vaccination or serologic testing, time from vaccination to antibody determination, and CD4 cell counts between children with and those without immunity.
Assuntos
Anticorpos Antibacterianos/sangue , Proteínas de Bactérias/imunologia , Infecções por HIV/imunologia , Vacinas Anti-Haemophilus/imunologia , Haemophilus influenzae/imunologia , Polissacarídeos Bacterianos/imunologia , Cápsulas Bacterianas , Proteínas de Bactérias/administração & dosagem , Pré-Escolar , Vacinas Anti-Haemophilus/administração & dosagem , Humanos , Lactente , Polissacarídeos Bacterianos/administração & dosagemAssuntos
Anticorpos Antibacterianos/imunologia , Proteínas da Membrana Bacteriana Externa/administração & dosagem , Vacinas Bacterianas/administração & dosagem , Haemophilus influenzae/imunologia , Neisseria meningitidis/imunologia , Pentosefosfatos/administração & dosagem , Polissacarídeos Bacterianos/administração & dosagem , Proteínas da Membrana Bacteriana Externa/imunologia , Vacinas Bacterianas/imunologia , Humanos , Esquemas de Imunização , Lactente , Pentosefosfatos/imunologia , Polissacarídeos Bacterianos/imunologiaRESUMO
STUDY OBJECTIVE: To determine what change, if any, occurs in the serum anticapsular antibody concentration immediately after immunization with either Haemophilus influenzae type b capsular polysaccharide vaccine (PRP) or a vaccine consisting of the capsular polysaccharide conjugated to diphtheria toxoid (PRP-D). SETTING AND PATIENTS: Children: a convenience sample of 32 healthy 2-year-old children from diverse locales. Adults: a convenience sample of 16 healthy adults chosen from employees at the Washington University and Tulane University schools of medicine. INTERVENTIONS: PRP or PRP-D vaccine administered to the adults and serum obtained daily for 5 days. PRP vaccine was administered to the children, and serum was sampled 2 or 3 days or 4 or 5 days after immunization, or both. MEASUREMENTS AND MAIN RESULTS: Decline in serum antibody in all seven (100%) adult recipients of PRP. The nadir occurred on days 1 to 3, and the decrease average 26.0% of the preimmunization concentration. Eight (89%) of nine PRP-D recipients had a similar decline that averaged 25.9%. Of 29 children, 20 (69%) had a decline that averaged 14.7%. The magnitude of anticapsular antibody present before immunization was correlated with the magnitude of the observed decrease. CONCLUSIONS: A decrease in serum anticapsular antibody occurs in most children and adults immunized with PRP (adults and children) or PRP-D (adults). Such a decrease might transiently increase the risk of invasive disease if it occurred during a period of asymptomatic colonization with H. influenzae type b.
Assuntos
Anticorpos Antibacterianos/análise , Vacinas Bacterianas/imunologia , Toxoide Diftérico/imunologia , Vacinas Anti-Haemophilus , Haemophilus influenzae/imunologia , Adulto , Cápsulas Bacterianas , Pré-Escolar , Suscetibilidade a Doenças/imunologia , Humanos , Imunização , Lactente , Polissacarídeos Bacterianos/imunologia , Fatores de TempoRESUMO
To evaluate the possibility that immunization with a capsular polysaccharide vaccine decreases immunity in the immediate postvaccination period and renders an animal susceptible to invasive Haemophilus influenzae type b disease, we passively immunized infant rat pups with an immune globulin preparation, vaccinated them with an H. Influenzae type b capsular polysaccharide vaccine at a wide range of doses, and challenged them with H. influenzae type b given intraperitoneally. Bacteremia occurred in 89% of protected, vaccinated pups compared with 17% of protected, unvaccinated pups (p = 0.0001). In protected, vaccinated pups the rate of bacteremia resembled that in unprotected, unvaccinated control pups and did not vary with the dose of vaccine administered. The magnitude of bacteremia and the incidence of meningitis in protected, vaccinated pups exceeded that occurring in the protected, unvaccinated control animals, but these effects diminished with the dose of vaccine. Diminution of anticapsular antibody occurred in association with the largest doses of vaccine. We conclude (1) that the administration of H. influenzae type b capsular polysaccharide vaccine in infant rats is associated with a diminution of passively acquired anticapsular antibody immediately after vaccination and (2) that experimental challenge with H. influenzae type b at this time produces disease resembling that in animals not passively given protection.