A-Z Pharma science

Antibiotic Resistance In today's blog, we will try to answer the question on antibiotics resistance, and with it, we will also be discussing combination therapy and its related complications. So, what is resistance? According to WHO drug resistance is a state of insensitivity and it refers to the unresponsiveness of microorganisms to an Antibiotic. Now, the question is when does a microbe become resistant? Antibiotic resistance happens when the microbes no longer react to the antibiotics. They continuously grow by developing an ability to defeat the drugs built to kill them. Have you ever wondered why? causes of resistance Some organisms are inherently resistant to antibiotics. However microbial species that are generally responsive to a specific drug may develop more virulent or resistant strains through spontaneous mutation or acquired resistance and selection. Some of these strains may even evolve resistant to more than one antibiotic. The different mechanisms by whi...

Introduction In our previous blog , we’ve discussed THE PRINCIPLES OF ANTIBIOTICS , so that you can get a basic idea about the chapter. Today we’ll talk about β-LACTAM ANTIBIOTICS. β-LACTAM ANTIBIOTICS:    Þ    β-lactam antibiotics are called so due to the presence of β-lactam ring in their structure.      Þ    All of them i.e., Penicillin, Cephalosporin, carbapenem , and monobactams share a common mechanism of action (inhibition of synthesis of the bacterial peptidoglycan cell wall.      Þ    Inhibited by the β-lactamase enzyme.      Þ    Bactericidal in nature. PENICILLIN:      Þ    The Accidental Discovery:         In 1928, while studying Staphylococcus variants in his laboratory, Sir Alexander Flemming observed a mold contaminating one of his cultures resulting in bacterial lysis. The broth in which the fungus was developed showed inhibi...

Introduction Antibiotics are ligands whose receptor are microbial proteins that function on the biochemical difference that exists between microorganisms and humans, they have the ability to selectively injure or kill an invading microorganism without harming the cells of the host. They are one of the few drugs which can cure, and not just suppress the disease. These are the most frequently used as well as misused drugs. Antibiotics or Antimicrobial agent (AMA):   designate synthetic as well as naturally obtained drugs that selectively suppress the growth of or kill other microorganisms. Classification :  A . Biochemical Pathways: B. Chemical structure: C . Class:  Antibacterial: Penicillins, Aminoglycosides, Erythromycin, Fluoroquinolones, etc. Antifungal: Griseofulvin, Amphotericin B, Ketoconazole, etc. Antiviral: Acyclovir, Amantadine, Zidovudine, etc. Antiprotozoal: Chloroquine, Pyrimethamine, Metronidazole, Diloxanide, etc. Anthelmintic: Mebendazole, Pyrantel, Ni...

Second Messengers Involved in GPCRs Earlier we have discussed the basics of signal transduction, G-protein coupled receptor( GPCR ) and its basic signaling pathway. Now we’ll discuss the Targets of G-proteins / Second Messenger Systems involved in it. Most important 5 key factors in receptor mechanism: Second messengers are the molecules that convey the signals received on the cell surface via receptor to target molecules in the cytoplasm or in the nucleus. They also play a major role in the amplification of the signals. cAMP Pathway: cAMP (cyclic 3,5- adenosine monophosphate) is a nucleotide synthesized in the cell by the membrane-bound enzyme   Adenylyl Cyclase (AC) . Adenylyl cyclase catalyzes the cyclization of ATP→ cAMP by cleaving pyrophosphate (PPi). AC is activated by G s α subunit and inhibited by the G i α subunit. Thus, modulation of the catalytic activity of AC controls the increase or decrease in the concentration of cAMP in the cell. PKA: cAMP activates the enzym...

Nuclear Receptor Nuclear receptors are intracellular receptors that bind to small lipophilic ligands which diffuse through the membrane to interact with the target. The receptor-ligand complex activates the transcription factors in the nucleus and either activate or repress the transcription of mRNA and the synthesis of proteins. These receptors have prolonged actions lasting through hours to days. Structure of the Receptor: Nuclear hormone receptors contain four major domains: The N-terminal ligand-binding domain (12 helices) contains an activation region (AF-1) essential for transcriptional regulation followed by two zinc fingers that bind to DNA (the DNA-binding domain). The C-terminal contains a hinge region and a ligand-binding domain with specific sets of amino acid residues for binding co-activators and co-repressors in second activation region (AF- 2).  Structure of the nuclear receptor Types of Nuclear receptor: Signal Transduction Pathway:...

A cell for its own survival performs gene transcription, connects via cell signaling, maintains its ionic balance, and undergo many such physiological functions. For all these, proper signal transduction is crucial and that occurs via receptors. The receptors' various components and its mechanistic pathway will be discussed here: Receptors on the surface of cells have two major functions:           (1) Ligand Binding      (2) Message Propagation Two functional domains are present within the receptor:           (1) A Ligand Binding Domain (LBD)   (2) An effector domain SIGNAL TRANSDUCTION PATHWAY: The actions of a receptor imply directly on its cellular target , on effector proteins, or on Transducers (intermediate cellular signaling molecules). In maximum cases, the ultimate target of a receptor is an enzyme, ion channel or transport protein that create/move/degrade sm...