QUINOLINE AND IT'S DERIVATIVES Cudjoe Francis, group 2. Scientific adviser is Tishakova Tatyana

QUINOLINE AND IT'S DERIVATIVES

Cudjoe Francis, group 2. Scientific adviser is Tishakova Tatyana.

Quinoline is used principally for the manufacture of nicotinic acid, which prevents pellagra in humans, and other chemicals. Several methods are known for its preparation, and production of synthetic quinoline exceeds that from coal tar.

Several alkaloids (alkaline organic compounds produced in plants) are members of the quinoline family; these include quinine and other derivatives from the cinchona tree. The antimalarial drugs chloroquine and amodiaquin are synthetic quinoline compounds, as are dibucaine hydrochloride, a long-acting local anesthetic, and cyanine, the oldest of an important class of dyes.

PENICILLIN

Nathaniel Jojo Sam, group 2. Scientific adviser is Tishakova Tatyana.

It is an antibiotic derived from Penicillium fungi. It was among the first drugs to be effective against many previously serious diseases, such as syphilis and infections caused by staphylococci and streptococci.

There are several kinds of penicillin synthesized by various species of the mold Penicillium and they may be may be divided into two classes: The naturally occurring penicillins (those formed during the process of mold fermentation) and the Semisynthetic penicillins (those in which the structure of the chemical substance, 6-aminopenicillanic acid, found in all penicillins is altered in various ways).

Some naturally ocurring penicillins include penicillin G and the more acid-resistant penicillin V. But they are inactive against many serious pathogens. Semisynthetic penicillins include Ampicillin, Carbenicillin and Oxacillin which are more active in resistance to stomach acids so that they can be taken orally and a degree of resistance to penicillinase (a penicillin-destroying enzyme produced by some bacteria).

All types of penicillins work in the same way. They inhibit the bacterial enzymes responsible for cell wall synthesis and activate other enzymes to break down the protective wall of the microorganism. Therefore, they are not effective against microorganisms that do not produce cell walls.

Penicillins are used in the treatment of throat infections, meningitis, syphilis, and various other infections.

The first bug to battle penicillin was Staphylococcus aureus. This bacterium is often a harmless passenger in the human body, but it can cause illness, such as pneumonia or toxic shock syndrome, when it overgrows or produces a toxin.

Cephalosporins

Josephine Nemi, group 2. Scientific adviser is Tishakova Tatyana.

1. 
   Prevents cell wall synthesis by binding to enzymes called penicillin binding proteins (PBPs). These enzymes are essential for the synthesis of the bacterial cell wall.
   
2. 
   Bactericidal.
   
3. 
   Concentration-independent bactericidal activity, with maximal killing at 4-5 times the MIC of the organism.
   

In general, 1st generation cephalosporins have better activity against gram-positive bacteria and less gram-negative activity, while 3rd generation agents, with a few exceptions, have better gram-negative activity and less gram-positive activity. The only fourth generation agent has both gram-positive and gram-negative activity.

In general, 1st generation cephalosporins have better activity against gram-positive bacteria and less gram-negative activity, while 3rd generation agents, with a few exceptions, have better gram-negative activity and less gram-positive activity. The only fourth generation agent has both gram-positive and gram-negative activity.

MECHANISMS OF BACTERIAL RESISTANCE

It is not uncommon for several resistance mechanisms to be operating simultaneously.

1. 
   destruction of beta-lactam ring by beta-lactamases; an intact beta-lactam ring is essential for antibacterial activity
   
2. 
   altered affinity of cephalosporins for their target site, the penicillin binding proteins
   
3. 
   decreased penetration of antibiotic to the target site, the PBPs. This is only applicable to gram-negative bacteria because gram-positive bacteria lack an outer cell membrane, and therefore penetration to the target site is not a problem.
   

PURINE

Katrina Mwaalwa Uutoni, group 2. Scientific adviser is Tishakova Tatyana.

Heterocyclic compound form the largest group of organic compounds and many have important biological properties. The main heteroatom that occurs in heterocyclic compounds is nitrogen, but there are also ring containing oxygen and sulfur. They are classified in accordance with the following features of their skeleton: according to the ring size, according to the number of heteroatoms and their mutual arrangement in ring, according to a degree of saturation of a matter and according to the number of the rings.

A purine is a heterocyclic aromatic organic compound. It consists of a pyrimidine ring fused to an imidazole ring. Purines, which include substituted purines and their tautomers, are the most widely occurring nitrogen-containing heterocycle in nature. Purines and pyrimidines make up the two groups of nitrogenous bases, including the two groups of nucleotide bases. Two of the four deoxyribonucleotides and two of the four ribonucleotides, the respective building-blocks of DNA and RNA, are purines. Apart from the crucial roles of purines (adenine and guanine) in DNA and RNA, purines are also significant components in a number of other important biomolecules, such as ATP, GTP, cyclic AMP, NADH, and coenzyme A. Purine itself has not been found in nature, but it can be produced by synthesis. They may also function directly as neurotransmitters, acting upon purinergic receptors.

A moderate amount of purine is also contained in beef, pork, poultry, other fish and seafood, asparagus, cauliflower, spinach, mushrooms, green peas, lentils, dried peas, beans, oatmeal, wheat bran, wheat germ, and hawthorn.

REFERENCE:

1. En.wikipedia.org/wiki/purine

2. Fundamentals of Biologic Chemistry, Zurabyan S E, 2003, ISBN59231-0311-7

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