When Streptomyces undergoes conjugation transfer, it is always contaminated by a type of yellow Pseudomonas. What could be the reason for this?

Contamination by yellow Pseudomonas during Streptomyces conjugation transfer can occur due to several reasons. Understanding these reasons can help in mitigating the contamination and ensuring successful conjugation. Here are some potential causes and solutions:

Potential Causes of Contamination

Shared Growth Media and Conditions:Nutrient-Rich Media: Media that supports the growth of Streptomyces might also be conducive for Pseudomonas. Pseudomonas species are opportunistic and can grow in various media, especially those rich in nutrients. Environmental Conditions: Conditions such as temperature, pH, and humidity that are optimal for Streptomyces conjugation may also support Pseudomonas growth.

Cross-Contamination During Handling:Laboratory Practices: Contamination can occur due to inadequate sterile techniques during media preparation, inoculation, or transfer. Cross-contamination can happen through shared equipment, pipettes, or workspaces. Human Error: Handling errors, such as touching sterile surfaces with contaminated gloves or using non-sterile tools, can introduce Pseudomonas into the culture.

Intrinsic Presence of Pseudomonas:Soil and Environmental Samples: Streptomyces and Pseudomonas can coexist in natural environments like soil. If environmental samples are used, Pseudomonas may already be present and proliferate during incubation. Latent Contaminants: Pseudomonas might be present in low numbers initially and become more prominent when conditions favor their growth during the conjugation process.

Resistance to Antibiotics:Antibiotic Resistance: Pseudomonas species are known for their intrinsic resistance to many antibiotics. If the media used for Streptomyces conjugation contains antibiotics that do not inhibit Pseudomonas, they can outgrow and contaminate the culture.

Solutions to Prevent Contamination

Optimize Selective Media:Selective Agents: Use selective media that supports Streptomyces growth but inhibits Pseudomonas. Add specific antibiotics or selective agents that Streptomyces are resistant to but Pseudomonas are not. Customized Media: Adjust nutrient levels, pH, and other media components to favor Streptomyces while making it less favorable for Pseudomonas.

Improve Sterile Techniques:Aseptic Practices: Ensure strict aseptic techniques during all steps of media preparation, inoculation, and handling. Use sterile gloves, tools, and work in a laminar flow hood if possible. Regular Cleaning: Clean and sterilize workspaces and equipment regularly to prevent contamination.

Use Pure Cultures:Isolate Streptomyces: Start with a pure culture of Streptomyces. Isolate single colonies and verify purity before starting the conjugation process. Monitor for Contaminants: Regularly check cultures for contaminants by streaking on selective and non-selective media to identify unwanted microorganisms.

Antibiotic Treatment:Pre-Treatment: Treat initial samples with antibiotics to which Pseudomonas is sensitive before starting the conjugation process. Antibiotic Selection: Use a combination of antibiotics in the media that target a broad spectrum of bacteria, including Pseudomonas, but ensure Streptomyces are resistant to these antibiotics.

Physical Separation:Isolate Procedures: Physically separate procedures involving Streptomyces conjugation from other microbial work to reduce cross-contamination risks. Dedicated Equipment: Use dedicated equipment and consumables for Streptomyces work.

Has anyone tried freeze flow samples in -80C freezer or liquid nitrogen before processing?

If the weghts of convolution kernel in CNN(convolution neural network) are pre-designable, or weights must be initialized and updated while trainning?

In CNN, is the feature map obtained randomly by convolution kernel?

How do the Maxent use to prediction the distribution of the cave fishes in Karst area?

Help me find the full text. I can only find the summary part in many databases, and I can't see the specific content. The author did not reply to me ?

Help me find the PDF, not only the abstract?

The components of a pancreatic exocrine organoid using mice pancreas?

Any ideas on how to get better bands?

The pH of the deionized water in the lab is suddenly much higher. Any thoughts why?

Does the temperature of the optical film need to reach the melting temperature when thermal damage occurs?

Could it be a cell culture contamination?

E.coli contamination in human RNA seq data ?

How can we now if the promotor in the vector is well?

Can anyone help me explain my problem?

How to interpret results of AST for Pseudomonas aeruginosa?

Are my cells contaminated with mycoplasma?

Does the soil contamination correction factor for decomposing leaf biomass vary according to space and season?

Black dots like contamination in my cell cultures. What are they?

What is meant by cross-contamination and what causes fruits and vegetables to become contaminated during preparation and storage?

Why can't we get on top of this incubator infection (fungal)?