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.

The biggest and perhaps most fearsome of the world's big cats, the tiger, shares 95.6 percent of its DNA with humans' cute and furry companions, domestic cats.

The new research showed that big cats have genetic mutations that enabled them to be carnivores. The team also identified mutations that allow snow leopards to thrive at high altitudes.

Reference:

http://www.nbcnews.com/science/your-cat-ferocious-tigers-share-lot-95-6-percent-their-4B11182690

http://timesofindia.indiatimes.com/home/environment/flora-fauna/Gene-mapping-of-tiger-completed/articleshow/22671681.cms

Paper:

http://www.nature.com/ncomms/2013/130917/ncomms3433/full/ncomms3433.html

More at http://www.hiit.fi/postdoc-call-2013

http://en.wikipedia.org/wiki/Sequence_assembly 

https://genomebiology.biomedcentral.com/articles/10.1186/s13059-016-0951-y

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

WALK-IN-INTERVIEW

Walk-in-test cum interview for selection to the following temporary assignments sanctioned under the DBT sponsored adhoc time bound research scheme entitled "Establishment of a Sub-DIC" will be held at CPCRl, Kudlu PO, Kasaragod District, Kerala -6711 24 on the date and time indicated against each:

Project Assistant

Qualification: Essential: Masters Degree in Bioinformatics / B.Tech Degree in Bioinformatics

Desirable: 1. Experience in the field of bioinformatics
2. M.Phil / Doctoral degree in the field

Date of interview 24.09.2013 at 10.00 a.m.

Trainee – 2 Posts

Essential: Masters Degree in Bioinformatics or B.Tech Degree in Bioinformatics.

Date of interview 25.09.2013 at 10.00 a.m.

Studentship – 2 Posts

Essential Final Year/Semester students of MSc Bioinformatics or B.Tech Bioinformatics

Date of Interview 25.09.2013 at 10.00 a.m.

The candidates fulfilling the above eligibility criteria for Item No.1 & II shall apply online and walk-in for a written test and interview at CPCRI, Kasaragod on the respective dates at 10.00 a.m. The candidates for Studentship should submit the application through their Head of the Department. They shall also bring with them a set of bio data and original certificates in proof of age, educational qualifications, experience etc. Candidates who fail to produce the original of the Degree/PO certificates OR provisional certificate will not be allowed to attend the test / interview. Those who are qualified in written test will only be permitted to attend the interview.

No TA will be paid for the journey for attending the interview.

Advertisement: http://www.cpcri.gov.in/images/images/opportunity/sep4_opp.pdf

Availability and implementation: Source code and binaries are freely available at https://github.com/rrwick/Bandage. Bandage is implemented in C++ and supported on Linux, OS X and Windows. A full feature list and screenshots are available at http://rrwick.github.io/Bandage.

Address of the bookmark: http://rrwick.github.io/Bandage/

An exciting opportunity exists for a highly motivated and enthusiastic bioinformatics researcher to work in the Exosome, Secretome and Systems Biology laboratory of Dr Suresh Mathivanan. This position is funded through the National Institutes of Health (NIH) USA, to study the role of extracellular RNA or ExRNA in intercellular communication.

The successful applicant will be involved in collaborative bioinformatics research with more than 30 American Universities/Institutes. The ExRNA consortium is a multi-institute USD 17 million funded program which has 5 primary aims: to understand the biogenesis of ExRNA (vesicles and non-vesicles), to explore the use of ExRNA in biomarker research, to establish a reference profile of ExRNA in various disease conditions, to explore the role of ExRNA in therapeutic purposes and to manage the generated data through a reference portal. The bioinformatics component is critical in managing and analysing the data generated by the entire consortium. The researcher is required to contribute to the management and perform the analysis of ExRNA data.

The candidate to succeed, you will possess:

Experience in the analysis and modelling of data, including the capacity to integrate data from a range of sources and of uneven quality.

Evidence of experience in research and of the ability to work effectively under limited supervision or independently.

A record of contribution to publications, conference papers and/or reports, or professional or technical contributions which provide evidence of research potential.

Completion of a doctoral degree in bioinformatics or biostatistics with a focus on transcriptomic data will be highly regarded.

Preference will be given to applicants with competence in programming (JavaScript, Perl/Python), any web-based applications (PHP, ZOPE) and relational databases (MySQL).

Closing date: 30 September 2013

Position Enquiries: Dr Suresh Mathivanan (s.mathivanan@latrobe.edu.au)

More at http://www.mathivananlab.org/

See http://mash.readthedocs.org for more information.

Address of the bookmark: https://github.com/marbl/Mash/releases

More at http://pandeylab.igm.jhmi.edu/

http://scholar.google.com/citations?user=OhuG0FcAAAAJ&hl=en