Before you go down that path, consider this critical biological question:
Are you sequencing human cells—or bacterial contamination?

The Silent Saboteur: Mycoplasma in Cell Cultures

Mycoplasma contamination remains one of the most widespread and underdiagnosed issues in tissue culture work. Studies suggest that 15–35% of cell lines in use may be contaminated, often without visible signs. Unlike other microbial infections, Mycoplasma does not produce cloudiness, odor, or a change in pH. Many researchers won’t detect it unless they specifically test for it.

The consequences, however, are profound. Mycoplasma can significantly alter:

• Host gene expression patterns

• Cell proliferation rates

• Epigenetic profiles and chromatin accessibility

• Cytokine signaling and immune responses

In short, it can skew your results, compromise your biological conclusions, and invalidate weeks or months of research.

A Simple Diagnostic Step: Map Against Mycoplasma Genomes

If you encounter poor alignment rates to the human genome, consider mapping your reads to a Mycoplasma reference genome—or better yet, use a combined human + Mycoplasma reference. There have been cases where over half of all reads, initially assumed to be from human cells, were in fact bacterial in origin. This check is fast, easy, and could save your project.

How Contamination Happens—and Persists

Mycoplasma is small (0.1–0.3 μm), lacks a cell wall, and can pass through standard filters undetected. Common sources include:

• Contaminated reagents (e.g., FBS)

• Infected cell lines obtained from other labs

• Poor aseptic technique or shared equipment

Once present, it spreads quickly between cultures and can persist for months, silently affecting results.

Why Treatment Is Difficult

While antibiotics such as Plasmocin or BM-Cyclin are sometimes used, they often offer only partial resolution and may themselves alter cell behavior. In many cases, the best course of action is to discard the contaminated culture and start with a fresh, verified stock.

Practical Recommendations for Researchers

• Routinely test for Mycoplasma using PCR, qPCR, or fluorescence-based assays

• Incorporate contamination screens into your sequencing QC pipeline

• Use combined reference genomes when mapping ambiguous reads

• Practice strict aseptic technique and monitor all incoming cell lines

• Don’t ignore unexplained data anomalies—they might point to contamination

Closing Thought: Contamination Is a Biological Variable

It’s easy to view poor mapping as a technical issue, but sometimes the problem lies deeper—in the biology itself. Mycoplasma contamination doesn’t just interfere with sequencing; it interferes with science. As a research community, we must treat contamination not as an afterthought, but as a key variable to control.

So next time your reads won’t align, don’t just tune the aligner. Ask if your cells are telling the truth—or if they're hiding something.

• Function(data, options)

Even quit is a function

• q()

So is help

help(read.table)

Provides the help page for the FUNCTION ‘read.table’

help.search(“t test”)

Searches for help pages that might relate to the phrase ‘t test’

NOTE: quotes are needed for search strings, they are not needed when referring to data objects or function names.

There is a short cut for help,

? shows the help page on a function name, same as help(function)

?read.table

?? searches for help pages on functions, same as help.search(‘phrase’)

??“t test”

Information is usually returned from a function, by default this is printed to screen

read.table(‘data.tsv’)

This can always be stored, we call what it is stored in an ‘object’

mydata

here mydata is an object of type dataframe

Reminder:

• Vector: a list of numbers, equivalent to a column in a table
• Data Frame = a collection of vectors. Equivalent to a table

Hint:

• Up/Down arrow keys can be use to cycle through previous commands

Address of the bookmark: http://chmille4.github.io/Scribl/

Central University of Jharkhand has been granted funds by the Department of Biotechnology (DBT), Govt. of India to establish “DBT-Boost to CUJ Interdisciplinary Life Sciences Departments for Education and Research” Applications are invited for the Assistant Professor on purely temporary basis. The appointments shall be initially for a period of one year, renewable every year depending on the satisfactory performance, till the end of project.

Position: ASSISTANT PROFESSOR (Total 03)
Salary: 45,000/- (fixed) per month
Essential Qualifications: i. Good academic record with at least 55% marks (or an equivalent grade in a point scale wherever grading system is followed) at the master’s degree level with specialization in Biodiversity and Systematic/ Systems Biology/ Biophysics/ Bioinformatics from an Indian University, or an equivalent degree from an accredited foreign university. ii. Besides fulfilling the above qualifications, the candidates must have cleared the National Eligibility Test (NET) conducted by the UGC, CSIR or similar test accredited by the UGC like SLET/SET. iii. Notwithstanding anything contained in i. and ii. candidates, who are or have been awarded Ph.D Degree in accordance with the University Grants Commission (Minimum Standards and Procedure for Award of Ph.D. Degree) Regulation, 2009, shall be exempted from therequirement of the minimum eligibility condition of NET/SLET/SET for recruitment and appointment of Assistant Professor. iv. NET/SLET/SET shall also not be required for such disciplines for which NET/SLET/SET in not conducted.
Desirable: Preference will be given to candidates having Ph.D in any of the above mentioned areas with NET

IMPORTANT DATES TO REMEMBER :

Last Date to Apply for this job 24/3/2015

REFERENCE:

Central University of Jharkhand (CUJ) Recruitment 2015 – Advt. No.: CUJ/Advt./14-15/15 Date: 26th Feb. 2015.

More at http://cuj.ac.in/careers.php

If you use circlize in your publications, I would be appreciated if you can cite:

Gu, Z. (2014) circlize implements and enhances circular visualization in R. Bioinformatics. DOI: 10.1093/bioinformatics/btu393

Address of the bookmark: http://zuguang.de/circlize_book/book/

http://molbiolabccsumrt.webs.com/

Applications are invited for one post of RA in a DBT funded research project “Creation of Bioinformatics Infrastructure Facility (BIF) for the promotion of Biology Teaching through Bioinformatics (BTBI) Scheme of BTISet”.

Candidate should have a Ph.D. degree in Bioinformatics/Biotechnology/Genetics and Plant Breeding with adequate experience in the area of Bioinformatics. If a suitable candidate for the post of RA is not available, a JRF/SRF may be appointed.

Candidate for the post of JRF/SRF should have Master’s degree in relevant subject with adequate experience in the area of Bioinformatics and should be NET/DBT-BINC qualified

Interested candidates may send their bio-data to Prof. H. S. Balyan (hsbalyan@gmail.com) (in exceptional case, bio-data may also be submitted at the time of interview) and attend the interview on Monday, March 30, 2015 at 11:00 AM in the Department of Genetics & Plant Breeding, Ch. Charan Singh University, Meerut. Candidates shall bring their original documents at the time of interview for verification. No interview letters will be issued and no TA/DA will be paid.

Code in almost all popular languages using Coding Ground. Edit, compile, execute and share your projects, 100% cloud.

http://www.tutorialspoint.com/codingground.htm

Address of the bookmark: http://www.tutorialspoint.com/codingground.htm

Address of the bookmark: https://sourceforge.net/projects/genoviz/

DEPARTMENT OF BIOTECHNOLOGY

No. NITW/Bio/ Date: 30th March 2015

ADVERTISEMENT FOR PROJECT FELLOW (Research Staff)

Applications are invited for the post of Project Fellow (Research Staff) for the project entitled ‘Metagenome derived nitroreductases for degradation of nitro compounds’ sponsored by the Department of Science and Technology (DST-INSPIRE), Govt. of India.

Position: Project Fellow (1 No.)

Project Duration: 5 years

Note: The post is purely on temporary basis for a period one year and may be extendable till the end of the project based on the progress of the candidate.

Emoluments: Rs. 14,000/- per month (Consolidated) for first two years and Rs. 16,000/- per month (Consolidated) for next three years.

Essential Qualifications:

i) First class in M.Tech/M.S (Biotechnology/Industrial Biotechnology/Bioinformatics) or equivalent. Or

ii) First class in M.Sc. (Biotechnology/Bioinformatics/Biochemistry/ Microbiology/Molecular biology).

Desirable Qualification: Preference will be given to candidates who have cleared NET/GATE or having prior work experience in Molecular biology/Bioinformatics sequence analysis.

Interested candidates may submit their application in plain paper along with Curriculum Vitae and photocopies of certificates in support of educational/professional qualifications. Application should be sent in a closed cover with a superscription on the cover “Application for the post of project fellow (DST-INSPIRE)” on or before 20.04.2015 (Monday) via Post to the Principal Investigator. Eligible candidates will be intimated through e-mail and called for interview at the Department of Biotechnology, NIT, Warangal. No TA/DA will be paid for attending the interview. Dr. K. Divakar (Principal Investigator) DST-INSPIRE Faculty Department of Biotechnology National Institute of Technology Warangal – 506 004. Telangana, India. E-mail: divakar@nitw.ac.in; kdivak@gmail.com

Advertisement: http://www.nitw.ac.in/nitw/announcements/2015/Notification_Project_Fellow_DST_INSPIRE_Biotechnology_NITW.pdf