Skip to content
Login Register

#sample preservation

3 public questions tagged with this topic.

Animal Tissue Culture 1

EDTA acts as an inhibitor of:

Metalloprotease class distinguished by requirement zinc ion for catalytic mechanism and often calcium for structural integrity. Active site contains conserved motif HEXXH where histidines coordinate zinc plus third ligand histidine or glutamate forming tetrahedral geometry polarizing water molecule held nearby as hydroxide ion via general base glutamate abstracting proton making hydroxide nucleophile that attacks peptide carbonyl carbon forming tetrahedral transition state stabilized by zinc positive charge and nearby tyrosine oxyanion hole. Removal of zinc abolishes activity irreversibly. Ethylenediaminetetraacetic acid EDTA is hexadentate aminopolycarboxylate chelator with four carboxylate oxygen and two amine nitrogen electron pair donors wrapping divalent cation forming octahedral complex extremely stable formation constants log Kf Zn2+ sixteen point five, Ca2+ ten point seven, Mg2+ eight point seven at pH eight. Chelation strips Zn2+ from catalytic site and removes Ca2+ bridging extracellular cadherin domains or stabilizing metalloprotease beta propeller. This mechanistic insight supports diagnostic and therapeutic applications while reinforcing core immunological and cell biology principles taught in advanced curricula.

Ref: Lipscomb & Strater Chem Rev 1996 metalloprotease zinc HEXXH; Sigma EDTA chelation Zn Ca MMP inhibition detachment synergy.

View Details
Animal Tissue Culture 1

Protease inhibitors are added to prevent:

Innate immunity balances protease mediated tissue remodeling with protective antiproteases preventing autodamage. Neutrophils recruited to injury sites degranulate releasing azurophilic granules containing serine protease neutrophil elastase capable of degrading elastin collagen, cathepsin G, proteinase 3, and specific granules releasing matrix metalloproteases MMP8 collagenase and MMP9 gelatinase facilitating migration through basement membrane. Uncontrolled release would destroy cartilage and lung parenchyma causing emphysema in alpha-1 antitrypsin deficiency. Plasma contains defensive inhibitors: serpins alpha-1 antitrypsin AAT 52 kDa irreversible suicide substrate forming covalent complex with elastase, alpha-1 antichymotrypsin inhibiting cathepsin G, inter-alpha-trypsin inhibitor, and broad spectrum alpha-2 macroglobulin 720 kDa tetramer trapping proteases via bait region cleavage induced conformational change from expanded to compact enclosing enzyme inside physical cage sterically blocking large substrates, and tissue inhibitors metalloproteases TIMP-1 to TIMP-4 forming 1:1 complex with MMP zinc. This mechanistic insight supports diagnostic and therapeutic applications while reinforcing core immunological and cell biology principles taught in advanced curricula.

Ref: Lodish Molecular Cell Biology serpin α1 antitrypsin α2 macroglobulin; Alberts MBoC protease inhibitors serum protection lysis cocktail.

View Details
Biosphere reserve & Wild life sancturies

Cryopreservation is carried out at

Cryopreservation ensures long-term conservation by storing viable cells, tissues, gametes, embryos, seeds, and pollen at ultra-low temperature where metabolism essentially halts but viability retained upon thawing. Standard method uses liquid nitrogen at -196°C boiling point, with slow freezing or vitrification using cryoprotectants dimethyl sulfoxide DMSO and glycerol preventing intracellular ice crystal damage. Applications include preservation of endangered plant germplasm at NBPGR New Delhi, animal gamete biobanking at LaCONES Hyderabad, and microbial culture collections supporting future biotechnology. Knowledge of this distribution aids in understanding endemism patterns and UNESCO heritage site designations across India.

Ref: NBPGR Gene Bank Manual Cryopreservation -196°C; NCERT Biotechnology Principles Cryoprotectants

View Details