Gram-negative bacteria Essays

polymicrobial, typically dominated by obligatory anaerobic bacteria. The most commonly isolated microorganisms before root canal treatment include Gram-negative anaerobic rods, Gram-positive anaerobic cocci, Gram-positive anaerobic and facultative rods, Lactobacillus species and Gram-positive facultative Streptococcus species.83 The obligate anaerobes are rather easily eradicated during root canal treatment. In contrast, facultative bacteria such as non-mutans Streptococci, Enterococci, and Lactobacilli

Predation in the field This study confirms that invasive red king crab fed on both capelin eggs and capelin off the coast of Finnmark, Norway. Capelin was found in 81.6% and 21.7% of the analysed red king crab stomachs in 2005 and 2006, respectively, while capelin eggs were found in 23.2% and 10.0% of crabs in 2005 and 2006, respectively. These results are in accordance with a previous study where 19% of the analysed red king crab stomachs were reported to contain capelin eggs (Anisimova et al. 2005)

know, bacteria is a very complex organism and the subject can be very broad. In this essay, the focus will be on bacteria and the bacterial cell structure. Different forms of bacteria, its pros and cons, the cell structure, diseases and resistance will be explained and listed. First bacteria and cell structure is explained, and then moving on to different bacterial forms and diseases, and how diseases can be prevented or even cured. Then finishing the essay will be the conclusion. Bacteria The

Every organism in the universe requires water for its survival. Arguing out that water is good or bad is inconclusive. Water for human consumption is supposed to be subjected to quality tests so as to determine its safety for consumption and usage. A number of water sources around the globe suffer from some form of impurities. This makes it unsafe and unhealthy for individuals to use it. Challenges such as unsafe water, insufficient or the lack of quality healthy water has been an issue which has

fixing bacteria from rhizosphere Hypothesis: Rhizospheric Nitrogen fixing bacteria show optimal growth at PH: 6-7, Temperature: 30 °C and Salinity level: 0.005 – 0.010M NaCl INTRODUCTION: There is a huge bacterial diversity in rhizospheric soil. Gram-negative, non-sporulating baccilli which respond to root exudates are predominant in the rhizosphere (Pseudomonas, Agrobacterium). While Gram-positive bacilli, Cocci and aerobic spore forming bacteria like

Gentamicin, which is a broad spectrum aminoglycoside antibiotic (Fig. 1), belongs to the class of medicinal compounds capable of inhibiting the growth of Gram-positive and Gram-negative bacteria [1]. Gentamicin is one of the most effective drugs used in the treatment of serious suppurative and septic processes, especially those that are caused by Gram-negative microorganisms. The advantages of gentamicin over other aminoglycosides (kanamycin, neomycin) are its activity towards Pseudomonas aeruginosa and

What is the mechanism of action of colistin? Colistin is an antibiotic that works best against Gram-negative bacteria. It works by binding to LPSs (lipopolysaccrides) and phospholipids in the outer cell membrane of the bacteria. This, in turn, disrupts the outer cell membrane by displacing cations and leaking the intracellular contents, combining it with outer cellular contents, causing the bacteria to be unable to differentiate the bacteria’s intra and outer cellular contents from one another.

The hydroquinone metabolite purified from B. methylotrophicus MHC10 was evaluated for its antibacterial activity against a panel of several Gram-positive and Gram-negative bacterial pathogens. The zone of inhibition was used to evaluate the antagonistic activity of the metabolite. The standard antibiotics Ampicillin and Gentamycin were used as the positive control. Both antibiotics showed high antagonistic activity against all test pathogens. But in the case of P. aeruginosa, the hydroquinone treatment

different species – Shigella boydii, Shigella dysenteriae, Shigella sonnei, and Shigella flexneri. Several serotypes occur for each species based on O - antigen variations (Jennison & Verma, 2004; Morona, et al., 1995). Members of the genus are gram-negative, highly infective facultative intracellular pathogens, recognized as etiological agents of bacillary dysentery (shigellosis) (Kotloff, et al., 1999; Sansonetti, 2001). Shigella ranks third among the most common causes of bacterial gastroenteritis

4. The mechanism of action of cholera toxin The cholera toxin is an enterotoxin which is secreted by the gram-negative bacteria Vibrio cholerae. The toxin is an protein complex which is made up by six subunits, one A subunit and five B subunits. The A subunit is the enzymatic subunit and the B subunit is the binding subunit [9]. The cholera toxin is released from the bacteria and once in the intestinal lumen it adheres to the apical surface of the epithelial cell. The B subunit of the toxin binds

different types of membrane, our team did experiments on NRC-04 with negatively charged bacterial surface membrane mimetic micelles sodium dodecyl sulphate(SDS), zwitterionic eukaryotic middle membrane mimetic micelles dodecylphosphocholine(DPC), gram-negative bacteria outer membrane mimetic micelles Lipopolysaccharide(LPS) and bacterial inner membrane mimetic micelles 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol(POPG). Fluorescence test shows that the C-terminus tryptophan residue of NRC-04 interacts

the lab was to put into action the methods that have been learned in the laboratory to determine our unknown bacteria. Bacteria’s can have different features, shapes, and or arrangements that help microbiologist determined their role in our life (whether they are good or bad for humans). Bacteria can be classified as gram positive or negative (difference in call wall). Gram positive bacteria have a thick cell wall of peptidoglycan (“polymer of disaccharides cross-linked by shorts chains of amino acids”)

identify a specific bacterial species is an important skill. In order to discover and being able to identify any microbial bacteria, there a list of test one must perform in order to come with the right microorganism. It is fundamental to be aware of the risk of toxify, the resistance to antibiotics and determining how to prevent its growth and being able to destroy this bacteria. By being able to run both physical and chemical test to determine the identity of the mystery microbe is a unique and useful

“Post-Lab Questions” What ingredient(s) makes MacConkey agar selective for Gram-negative bacteria? The ingredients that make MacConkey’s Agar selective is a pH indicator (neutral red), and a disaccharide ( Lactose) “2. What types of bacteria are inhibited on MacConkey agar?” Gram-Positive bacteria that are inhibited with MacConkey agar due to crystal violet and bile salt presence . “3. What ingredient(s) makes MacConkey agar differential?” MacConkey agar are inhibited by a pH indicator (neutral

The six bacteria used in this lab were, Citrobacter freundii, Bacillus subtillis, Enterobacter aerogenes, Staphylococcus epidermis, Enterococcus durans, and Escherichia coli. Citrobacter freundii is a Gram-negative rod shape bacteria. The MSA plate will grow Citrobacter freundii, Bacillus subtillis, Enterobacter aerogenes and will have a yellow color change while Staphylococcus epidermis will not grow nor have a color change to yellow. The MacConkey agar will have growth with Escherichia coli, Enterococcus

different types of media plates affect the growth of skin microflora mainly microflora in the nostril It was hypothesized that the nostril microflora were gram-positive bacteria that belong to the genera Streptococcus, Staphylococcus and Propionibacteria. Results showed that the nostril microfloras were gram-positive (stained purple). However, gram staining was not enough to prove that the bacterium obtained from the nostril are Streptococcus, Staphylococcus, and Propionibacteria spp. The results do

my group ran for our unknown specimen, we had a match with the bacteria known as Alcaligenes Faecalis. This bacterium belongs to one of the major group of gram-negative bacteria (Phylum Proteobacteria). Alcaligenes Faecalis (Genus, species) is a rod shaped (bacillus), 0.5-1.2 x 1.0-3.0 µm, round with scalloped margin (colony configuration growth), motile (with one to nine peritrichous flagella), gram-negative, non-fermentative bacteria, obligate aerobic, having oxygen as the principal terminal electron

different bacteria was selected. The sample contained one gram-positive, one gram-negative paracolon, and one gram-negative coliform. The purpose of the experiment is to identify each of the three species that the mixture contained. After receiving an unknown mixture, the sample was streaked for isolation onto TSA, blood agar, and MacConkey plates. Each plate serves as a first step to identify the unknowns. The TSA (tryptic soy agar) can be used to do a gram stain, which differentiates gram-negatives

tube and plate to inoculating the bacterium and incubating. After incubated and grown the morphology was observed and several Gram stains were performed to determinate if the bacterium were gram positive or negative, and the morphology of the bacterium. The Gram Stain of my major unknown #202 was determinate to be Gram negative bacilli, and was double checked by the Gram check slide. Also I noticed that my bacterium was a facultative anaerobe and according to my results of endospore test, my bacterium

activities of different bacteria. Bacterial physiology differs from one species to the other. These differences in carbohydrate metabolism, protein metabolism, fat metabolism, production of certain enzymes and ability to utilize a particular compound help them to be identified by the biochemical tests. Gram’s stain was originally devised by histologist Hans Christian Gram in 1884. Gram-positive bacteria stain purple, while Gram-negative bacteria stain pink when subjected to Gram staining. Approximately