University:
Boston University
Course:
CGS NS 201 | Biology I
Academic year:

2023
Views:

360

Pages:

1
Author:

Giselle A.

Gram Positive Bacteria and Actinobacteria Non-spore forming, low gram positive GC bacteria include lactic acid bacteria and their relatives. The main genera include Staphylococcus, Micrococcus, Streptococcus, Lactobacillus, Sarcina. Phylogenetically, gram-positive bacteria are divided into low GC and high GC (Actinobacteria). Microccus is morphologically similar to Styaphylococcus although it is an Actinobacteria (high GC). Rod-shaped lactic acid bacteria or gram-positive cocci produce lactic acid as the main fermentation product.This group does not have porphyrins and cytochromes and does not carry out phosphorylation electron transport and obtains energy only from substrate level phosphorylation. Lactic acid bacteria are differentiated based on cell morphology, DNA base composition, phylogenetics fermentation type. Streptococcus, Enterococcus, Lactococcus, Leuconostoc and Pediococus have the same DNA base composition, whereas Lactobacillus has a variety of DNA bases. Lactobacillus are rod-shaped with different lengths, not wide, short or bent. Most are homofermentative, but some are heterofermentative. Lactobacillus delbrueckii is used to make yogurt. L. acidophilus for sour milk, other strains for salted vegetables. Bacteria are generally acid resistant, can grow below pH 4 compared to other lactic acid bacteria. Therefore, the isolation medium uses natural ingredients that are acidic and rich in carbohydrates, such as peptone tomato juice jelly. Streptomyces is a bacterium with a large number of species (500) and varieties. Antibiotic production is the main characteristic of bacteria that can be seen at the beginning of isolation and is able to lyse other bacterial colonies that grow nearby. Some antibiotics are produced from the Streptomyces group of bacteria. Chemical Class Aminoglycoside Tetracycline Macrolides Polyene There isn't any Antibiotic Streptomycin Spectinomycin Neomycin Tetracycline Chlortetracycline Erythromycin Clindamycin Nystatin Amphocetin B Chloramphenicol Bacteria Streptomyces griseus Streptomyces spp S. fradiae S. aureofaciens Saccharopolyspora erythraea S. lincolnensis S. noursei S. nodosus S. Venezuela

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