Paper 12 1. Temperate phages stages of interaction with susceptible bacterial cells. Prophage. Lysogeny. 2. Molecular-genetic methods of diagnosis and their significance. 3. Formation of normal microbiota in infants in breast-fed and bottle -fed children. 4. Bacterial exotoxins , their properties Classification of exotoxins by mechanisms of action and characteristic features of each group of exotoxins . Examples.

1. Temperate phages stages of interaction with susceptible bacterial cells:<br />Temperate phages, also known as lysogenic phages, have two distinct life cycles: the lytic cycle and the lysogenic cycle. In the lysogenic cycle, the phage DNA integrates into the bacterial chromosome and remains dormant. This integrated phage DNA is called a prophage. The prophage can replicate along with the bacterial cell without causing lysis. However, under certain conditions, the prophage can be induced to enter the lytic cycle, where it replicates and eventually causes the lysis of the bacterial cell.<br /><br />2. Molecular-genetic methods of diagnosis and their significance:<br />Molecular-genetic methods of diagnosis involve the analysis of genetic material, such as DNA or RNA, to detect the presence of specific pathogens or genetic disorders. These methods include polymerase chain reaction (PCR), DNA sequencing, and gene expression analysis. Molecular-genetic methods are highly sensitive and specific, allowing for the detection of pathogens or genetic disorders at an early stage. They are particularly useful in diagnosing infections caused by viruses, bacteria, or parasites, as well as in identifying genetic predispositions to certain diseases.<br /><br />3. Formation of normal microbiota in infants in breast-fed and bottle-fed children:<br />The formation of normal microbiota in infants is influenced by various factors, including feeding method. Breast-fed infants tend to have a more diverse and complex microbiota compared to bottle-fed infants. Breast milk contains various components, such as oligosaccharides, that promote the growth of beneficial bacteria in the infant's gut. In contrast, bottle-fed infants may have a less diverse microbiota due to the absence of these components in formula milk. The establishment of a healthy microbiota is crucial for the development of the immune system and overall health of the infant.<br /><br />4. Bacterial exotoxins, their properties, classification of exotoxins by mechanisms of action and characteristic features of each group of exotoxins. Examples:<br />Bacterial exotoxins are proteins secreted by certain bacteria that can cause harm to the host. They are highly potent and can cause a range of symptoms, from mild irritation to severe toxicity. Exotoxins can be classified based on their mechanism of action and their target cells. Some common classes of exotoxins include neurotoxins, enterotoxins, and cytotoxins. Neurotoxins affect the nervous system, enterotoxins affect the gastrointestinal system, and cytotoxins affect a wide range of cell types. Examples of bacterial exotoxins include botulinum toxin (neurotoxin), diphtheria toxin (cytotoxin), and cholera toxin (enterotoxin).