With the advent of genomic sequencing and genetic analysis in the 1990s, our understanding of the relationships between different microorganisms fundamentally changed. In light of this new knowledge, what exactly is the definition of a microbial species, and how should microbiologists be categorizing microorganisms? These questions are the focus of a new report released by the American Academy of Microbiology (AAM) entitled Reconciling Microbial Systematics and Genomics.
"It is clear that the current system for designating microbial species is somewhat functional, but inadequate in many ways. It is unclear whether this system should be replaced or renovated," says Richard Roberts of New England Biolabs, one of the authors of the report.
The report is the result of a colloquium convened by the AAM in September 2006. Participants with expertise in microbial taxonomy, systematics, ecology, physiology and other areas described the history of microbial taxonomy, the state of the field today, and how work in the field should proceed in the future. The report is a record of their comments and recommendations.
In the late 1800s, in order to make sense of the vast diversity of microbiological organisms, microbial taxonomists developed a system of placing microorganisms into categories in which each organism was granted a "genus" and "species" designation. At the time, physical (or phenotypic) properties were the only means of describing microorganisms, so the system was based on measurable and observable characteristics of the organisms, not genetic traits.
In the late 20th century, molecular biology uncovered the genetic relationships between microorganisms, and some of the secrets of microbes that had yet to be cultured in the lab (and hence phenotypically characterized) were revealed.
"Much of this new knowledge was incorporated into species descriptions, but difficulties in classification persisted and novel issues arose," says Roberts. "Conflicts exist between phenotypic and phylogenetic information, the means for classifying non-cultured microbes are limited under the current paradigm, and microbial species do not always demonstrate the phenotypic or genetic cohesiveness expected of them. For these reasons and others it has become clear that the species classification framework in use today is not capable of fully portraying and organizing microbial diversity."
The report contains an in-depth review of the myriad issues and conflicts involved in the classification of microbes in the post-genomic era, including a discussion on the definition of the term "species." It ends with a set of specific recommendations including, but not limited to:
- The establishment of a subcommittee within the International Committee on Systematics of Prokaryotes to consider a paradigm shift in the species definition.
- The need for more thorough study of the mechanisms of speciation before a more meaningful and practical species theory can be developed.
- The need for more comprehensive and systematic data to uncover whether microorganisms are organized into robust, definable, biologically meaningful clusters that adhere to the concept of species.
- The acquisition of draft-quality genome sequences for all type strains to help advance the integration of genomic information into our understanding of microbial diversity and enable researchers to map phenotypes to genomes.
Jim Sliwa | EurekAlert!
Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Power and Electrical Engineering
25.09.2017 | Health and Medicine
25.09.2017 | Physics and Astronomy