Related Experiment Video
Updated: Feb 13, 2026
13:19
The Use of Chemostats in Microbial Systems Biology
Published on: October 14, 2013
31.8K
Biological Diversity and Evolution of Type IV Secretion Systems
Peter J Christie1, Laura Gomez Valero2,3, Carmen Buchrieser2,3
1Department of Microbiology and Molecular Genetics, McGovern Medical School, 6431 Fannin St, Houston, TX, 77030, USA. Peter.J.Christie@uth.tmc.edu.
Current Topics in Microbiology and Immunology
|March 15, 2018
Summary
Bacterial type IV secretion systems (T4SSs) are diverse molecular machines that evolved from DNA conjugation systems. Recent studies reveal their complex evolution and broad distribution, particularly for type IVB secretion systems (T4BSSs).
Area of Science:
- Microbiology
- Molecular Biology
- Evolutionary Biology
Background:
- Bacterial type IV secretion systems (T4SSs) are versatile protein and DNA transporters.
- They are found in both Gram-negative and Gram-positive bacteria, enabling translocation to various cell types.
- T4SSs evolved from ancient DNA conjugation machinery.
Purpose of the Study:
- To summarize recent findings on the biological diversity of T4SSs.
- To focus on type IVA (T4ASS) and type IVB (T4BSS) secretion systems.
- To explore the evolutionary pathways and structural mosaicism within the T4SS superfamily.
Main Methods:
- Phylogenomics analyses to trace the evolutionary origins of T4SSs.
- Comparative analysis of representative T4ASS (Agrobacterium tumefaciens VirB/VirD4) and T4BSS (Legionella pneumophila Dot/Icm) systems.
- Examination of system composition, architecture, and subunit acquisition.
Main Results:
- T4SSs exhibit significant functional and structural diversity.
- T4ASS and T4BSS represent distinct subtypes with specialized substrate translocation capabilities.
- Evolution involved acquiring novel domains/subunits, leading to genetic and structural mosaicism.
- New phylogenomics data indicate T4BSSs are more widespread than previously thought.
Conclusions:
- T4SSs are highly evolved nanomachines with diverse roles in bacteria.
- Understanding T4SS evolution provides insights into bacterial adaptation and inter-species interactions.
- The broad distribution of T4BSSs highlights their importance in bacterial biology.
Related Concept Videos
01:29Diversity of Archaea IV
486
Hyperthermophilic archaea are a group of extremophiles thriving at temperatures above 80°C, often in hydrothermal vents and volcanic soils where conditions surpass the boiling point of water. At such temperatures, proteins, membranes, and DNA in most organisms degrade, but hyperthermophiles have evolved remarkable adaptations to maintain stability and function.Unique Cellular FeaturesHyperthermophilic membranes are composed of a monolayer of biphytanyl tetraether lipids, which resist...
486
02:55The Evidence for Evolution
48.4K
Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.
48.4K
01:27Diversity of Protists IV
1.1K
Amoebozoa represent a diverse group of terrestrial and aquatic protists that utilize lobe-shaped pseudopodia for locomotion and feeding. This characteristic differentiates them from the Rhizaria, which possess threadlike pseudopodia. The primary classifications within Amoebozoa include gymnamoebas, entamoebas, and the plasmodial and cellular slime molds. Phylogenetic evidence indicates that Amoebozoa diverged from a lineage that ultimately gave rise to fungi and animals.Gymnamoebas and...
1.1K
01:13Exocrine Glands: Types of Secretions
3.9K
Exocrine glands produce and release a variety of glandular products. Exocrine glands can be classified into serous, mucous, or mixed types based on their secretory products.
Serous glands produce watery secretions rich in digestive enzymes and proteins. The constituent cells of the serous gland have centrally located nuclei and eosinophilic secretory granules in the cytoplasm. The parotid gland is an example of a serous gland. It secretes saliva, which contains enzymes, such as lipases and...
Serous glands produce watery secretions rich in digestive enzymes and proteins. The constituent cells of the serous gland have centrally located nuclei and eosinophilic secretory granules in the cytoplasm. The parotid gland is an example of a serous gland. It secretes saliva, which contains enzymes, such as lipases and...
3.9K
01:27Drug Delivery Systems: Different Types
1
Conventional oral drug products, termed immediate-release (IR) formulations, are engineered to promptly release their active pharmaceutical ingredient (API) upon ingestion, typically in tablets or capsules. This rapid release often results in swift drug absorption and consequent pharmacodynamic effects, although the timing and intensity can vary depending on the drug's properties. Prodrugs within these formulations require metabolic conversion to activate their pharmacodynamic effects,...
1
01:54Convergent Evolution
33.1K
Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure leads to the rise of similar but unrelated adaptations in organisms with no recent common ancestors, a process known as convergent evolution.
33.1K