Bacterial docking and anchoring to the heart!

I apologise but I cannot indeed remember where exactly I saw this presentation slide for the first time (probably here), so I cannot refer back to the web document I got it from. But I was most intrigued about the concepts of docking and anchoring of bacteria to eukaryotic cells. Concepts I was partially unaware of on its biomolecular nature, but had a mild understanding of what could actually mean physically.

Bacterial adhesion can occur in two major ways:

In a basic primary fashion known as the docking stage and by secondary means known as locking or anchoring.

Docking is reversible and occurs between the bacterial cell surface and the surface of interest where electrostatic and hydrophobic interactions play a role [1].

Anchoring becomes irreversible if no prompt intervention takes place, and involves molecularly-mediated binding between specific adhesins and the compromised surface. This compromised agent subjected to an initial locking will become susceptible to a different range of adhering organisms, thus allowing a pluralised matrix to form in the shape of a biofilm varying in strain identities [1].

Both can lead to serious defense suppression, but the second can get the host death compromised by adding to antimicrobial drug resistance by compromising the glycocalyx (image below).

 [2]

The glycocalyx is a carbohidrate-enriched layer surrounding the outside of many eukaryotic and also prokaryotic cells. It basically reports on the health state of a cell and its disruption means disease! Especially in hyperglycemic subjects, thus diabetic patients are prone to loss of endothelial glycocalyx during accute hyperglicaemia [3].

If you want to know more about it read the articles below:

[1] Dunne, M. (2002). "Baterial adhesion: Seen any good biofilms lately?". Clinical microbiology reviews, 15(2), pp. 155-166.

[2] Rabelink and Zeeuw (2015). "The glycocalyx - linking albuminuria with renal and cardiovascular disease". Nature Reviews Nephrology, advanced online publication.

[3] Nieuwdorp et al., (2006). "Loss of endothelial glycocalyx during acute hyperglicemia coincides with endothelialdysfunction  and coagulation  activation in vivo". Diabetes, 55(2), pp. 480-486.

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TVC Bacterial endotoxin testing and bacterial identification Part I of III

Whenever I find jobs more related to practical microbiology and not so much free range like research is, I happen to meet very defined routines and modes of action. The job requirements for these very straightforward microbiology roles almost always cover three basic aspects: Total Viable Counts (TVC), Bacterial endotoxin testing and Bacterial identification. 

As with basically everything in life, there are numerous different ways of performing these techniques and obtain a successful outcome. But for those who are just starting or arent so familiar with these techniques, I believe it is of great help if we look into these in more depth.

Total Viable Counts is a test to estimate total numbers of viable (biologically functional) individual microorganisms (usually bacteria) present in a defined volume of sample. This is a technique abundantly used in verifying water and food quality. Different samples demand different parameters as so well explained in [1, 2] and a rigid set of conditions is just not feasible. Media, incubation temperature and even counting procedures change depending on the organisms metabolic requirements and the environment it is coming from. Because a TVC is simply an estimation they are usually interpreted as colony forming units (CFU) per a certain volume or area. A high TVC can tell one about how a vending machine is operating in terms of cooling efficacy, about the maintenance of the water reservoirs, etc.

When performing a TVC it is important to know exactly how to perform a serial dilution (see video for more details on a tenfold gravimetric dilution). Even though a serial dilution is considered to be a very simple and straightforward procedure the tiniest mistake can actually produce surreal results. To overcome counting difficulties a few companies developed tools that can help one on the process. There are plenty of great websites where you can collect important practical info on each tool and procedure techniques. The ones described in RapidMicrobiology are very well developed, especially good for reporting on TVC of food and beverages [4]. 

If youd like to take a look at practical TVC protocols that are also designed for fungal counting, access here on [3]. 

Next post we will be visiting the Bacterial endotoxin testing as well as the bacterial identification.Stay tuned!

[1] TVC Total viable count, Cheshire Scientific, [http://www.cheshirescientific.co.uk/microOrganisms/tvc.php], last visited on the 26th of November 2015, last update unknown.

[2] The significance of total viable counts, Watercoolers Europe, [http://www.watercoolerseurope.eu/expert-corner/bacteria-in-bottled-watercoolers-the-significance-of-total-viable-counts-tvcs-1], last visited on the 26th of November 2015, last updated on the 28th of September 2012.

[3] Total viable count with enrichment microbiological procedure, Lubrizol, [file:///C:/Users/mrxil/Downloads/TP-6TV0001_Total_Viable_Count_with_Enrichment.pdf], last visited on the 26th of November 2015, last updated on the 25th of August 2009.

[4] Rapid methods for total viable counts in food and beverages, RapidMicrobiology, [http://www.rapidmicrobiology.com/test-method/rapid-methods-for-total-viable-counts-in-food-and-beverages/], last visited on the 26th of November 2015, last update unknown.

Video by Shomus Biology, [https://www.youtube.com/watch?v=JtYtqpBLC14].

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