RESUMO
The role of pili and capsule was studied in neonatal infection with Escherichia coli K1. E coli strains were selectively cultured into three phases: mannose-sensitive (MS) piliated, non-mannose-sensitive (NMS) piliated, and nonpiliated. A high percentage of neonatal rats fed each phase of K1 strains developed bacteremia; there was no bacteremia with non-K1 strains or an acapsular mutant of K1 strain C94 (C94K-). Oral cavity colonization was noted in nearly 100% of rats fed K1 strains, non-K1 strains, or C94K-, regardless of the phase of piliation at feeding. Only MS piliated bacteria were found on oral cavity culture, indicating a rapid shift of NMS piliated and nonpiliated bacteria to the MS piliated phase. Conversely, only nonpiliated bacteria were found on blood culture when neonatal rats were fed piliated bacteria. Colonization of ileal epithelium was not observed. Thus, in vivo phase variation may be important in colonization and bacteremia with E coli K1.
Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli/fisiologia , Fímbrias Bacterianas/fisiologia , Polissacarídeos Bacterianos/fisiologia , Adesividade , Animais , Animais Recém-Nascidos , Escherichia coli/análise , Escherichia coli/ultraestrutura , Íleo/microbiologia , Mucosa Intestinal/microbiologia , Boca/microbiologia , Orofaringe/microbiologia , Ratos , Ratos Endogâmicos , Sepse/microbiologiaRESUMO
Ca2+, in homogenized lacrimal glands, enhanced phosphorylation of several peptides. Phosphorylation of two of these peptides was further stimulated by addition of the Ca2+-binding protein calmodulin and decreased by trifluoperazine, an inhibitor of Ca2+--calmodulin-dependent activity. Thus, Ca2+--calmodulin-dependent protein kinases and their substrates are present in lacrimal gland and could have an important role in lacrimal-gland function.
