This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'True about corynebacterium diptheria are all except : \nSelect and explain. \nA. Iron is required for toxin production, B. Toxin production is responsible for local reaction, C. Nonsporing, noncapsular and non motile, D. Toxin production is by lysogenic conversion', 'role': 'user'}, {'content': 'Answer: B \nExplanation: “Mechanical complications of diptheria are due to the membrane while the systemic effects are due to the toxin.”\n\nToxin acts mainly systemically though there are partial local effects.\nIt has affinity for myocardium, adrenals and nerve endings.\nToxin acts by inactivating EF-2 thus inhibiting protein synthesis.\nToxin production is influenced by iron concentration in the medium. Toxin production is optimal at 0.14 μ g/ ml and is suppressed at 0.5 μ g/ml.\nToxigencity of diptheria bacullus depends on symbiotic bacteriophages so it shows lysogenic or phage\n\nconversion i.e. nontoxigenic strain →→→→→ toxigenic strain by infecting with beta phage.\nRemember :\n\nCorynebacteria are gram positive, non acid fast, non sporing, non capsulated, non motile bacteria.\nIt contains polar bodies or volutin or babes-ernst or metachromatic granules of polymetaphosphate which are more gram positive.\nGranules are also stained by loeffler’s methylene blue, Albert’s, Neisser’s and ponder’s stain.', 'role': 'assistant'}]