<span>he Streptococcus pneumoniae capsule is vital for virulence and may inhibit complement activity and phagocytosis. However, there are only limited data on the mechanisms by which the capsule affects complement and the consequences for S. pneumoniae interactions with phagocytes. Using unencapsulated serotype 2 and 4 S. pneumoniae mutants, we have confirmed that the capsule has several effects on complement activity. The capsule impaired bacterial opsonization with C3b/iC3b by both the alternative and classical complement pathways and also inhibited conversion of C3b bound to the bacterial surface to iC3b. There was increased binding of the classical pathway mediators immunoglobulin G (IgG) and C-reactive protein (CRP) to unencapsulated S. pneumoniae, indicating that the capsule could inhibit classical pathway complement activity by masking antibody recognition of subcapsular antigens, as well as by inhibiting CRP binding. Cleavage of serum IgG by the enzyme IdeS reduced C3b/iC3b deposition on all of the strains, but there were still marked increases in C3b/iC3b deposition on unencapsulated TIGR4 and D39 strains compared to encapsulated strains, suggesting that the capsule inhibits both IgG-mediated and IgG-independent complement activity against S. pneumoniae. Unencapsulated strains were more susceptible to neutrophil phagocytosis after incubation in normal serum, normal serum treated with IdeS, complement-deficient serum, and complement-deficient serum treated with IdeS or in buffer alone, suggesting that the capsule inhibits phagocytosis mediated by FcÎł receptors, complement receptors, and nonopsonic receptors. Overall, these data show that the S. pneumoniae capsule affects multiple aspects of complement- and neutrophil-mediated immunity, resulting in a profound inhibition of opsonophagocytosis.</span>
Answer: C, chromosome replication
Explanation:
A, B, and D only occur in meiosis, as crossing over is required for genetic variation, which isn't needed in mitosis, reduction division is when diploids are reduced to haploids, which only happens in meiosis, and homologous chromosomes making tetras doesn't occur in mitosis either. However, during interphase of both mitosis and meiosis, chromosomes (DNA more specifically) are replicated.
Answer:
Specialist
Explanation:
We could also refer to these finches as specialists. They are niche-specific; that is, they survive under narrow, unique circumstances. I got it wrong when i did it on usatestprep, Specialist was right.
Answer:
★ A nonrenewable resource that developed from the remains of ancient plants that lived in large swamps millions of years ago is COAL
Explanation:
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Answer:
A crow does move its head with its eyes fixed.
Explanation:
Birds Eyes Are Fixed, So Their Neck Compensates To Hold Vision Steady. If a bird is moving and its wants to keep its eyes looking at something while it is moving then its body must compensate.