Small Things Considered

The Three Faces of Thiomargarita

by Merry

How inappropriate to call this planet Earth when it is quite clearly Ocean.
            Arthur C. Clarke

Budding is evident on these attached, elongated Thio-
margarita-like bacteria collected near a methane seep off
the coast of Costa Rica. Bar = ~1 mm. Source.

Ahhh, the delicious aroma of hydrogen sulfide. When as kids we encountered  it, we would hold our nose and proclaim “yuck, rotten eggs!” It is indeed produced by something ‘rotting,’ but specifically rotting under anaerobic conditions, such as in swamps and sewers. It is also abundant in coastal marine sediments, produced by the oxygen-consuming heterotrophic decomposition of organic matter. This makes for a layer at the sea bottom that is sulfide rich but oxygen poor. Nevertheless, leaving no potential energy source untapped, some bacteria in these zones use sulfur oxidation as their energy source. They include two remarkably large γ-proteobacteria, Thioploca and Thiomargarita. Thioploca copes with the lack of oxygen by using nitrate as an alternate terminal electron acceptor, but this just exchanges one problem for another. The sulfides are in the sediment, the nitrate in the water column above. So Thioploca commutes between the two zones, as Elio described in an earlier post.

Thiomargarita namibiensis, the “Namibian sulfur pearl.”
Courtesy of the Microbiological Garden. Source.

Non-motile Thiomargarita uses a different tactic. This bacterium was first discovered in 1999 off the Namibian coast, thus was named T. namibiensis. Its cells are large spheres, arranged in chains, each chain enclosed in a mucous sheath. Average cell diameter is 180 μm, with rare individuals reaching 750 μm, which is about as big as bacterial cells get. But they do this by cheating. Most of the ‘cell’ is a large vacuole, with the cytoplasm relegated to a thin surrounding outer layer. Sulfur globules are evident in the cytoplasm. Thus the genus name, Thiomargarita, that was derived from the Greek for ‘sulfur pearl.’ Thiomargarita spp. are widespread in hydrogen sulfide-rich coastal sediments. They, too, use nitrate as their terminal electron acceptor. Their strategy is to take advantage of the occasional events that resuspend the sediment and bring abundant nitrates into the water column. They then hoard nitrate in their huge vacuoles—enough nitrate to see them through even months of scarcity.

Thiomargarita from seeps in the Gulf of
Mexico reproduce by reductive division
in three dimensions, forming clusters
of 2, 4, 8, or 16 cells. Source.

But not all Thiomargarita form the characteristic “chain of pearls.” Exploration of hydrocarbon seeps in the Gulf of Mexico in 2005 turned up Thiomargarita-like cells with a distinctly different morphology. These organisms undergo a reductive division to yield clusters of 2, 4, 8, or 16 cells, each with the characteristic Thiomargarita-like spherical morphology with a large vacuole and a thin layer of cytoplasm with sulfur globules.

Yet a third morphological variety has been recently discovered. Researchers exploring the ecology of methane seeps along the Pacific margin of Costa Rica (depths of 990-1600 m) recognized the familiar Thiomargarita forms in the sediment. But in some regions they also noticed “thin films of microbial biomass” covering many surfaces.

Elongate Thiomargarita-like cells attached to Bathy-
modiolus mussel byssal threads. Bar = 500 μm. Source.

A close look revealed what appears to be a dense carpet of elongated Thiomargarita-like bacteria. These thickly cover some of the methane-derived authigenic carbonate rocks and the byssal threads that attach certain mussels to the substrate. Most frequently they’re seen adhering to various invertebrates. And quite an amazing sight they make! The attached cells have that Thiomargarita look: a thin-layer of sulfur globule-containing cytoplasm surrounding a single large vacuole. They’re average length is 338 μm, but some stretch to 700 μm. Small, spherical cells often appear to be budding from their unattached poles. The researchers brought samples on board so they could follow this budding process for their entire ten day cruise. From this they calculated that each day one bud in 300 detached from the parent cell.

Budding caught in the act. The arrow 3 indicates
initial bud formation, arrow 5 a spherical
daughter cell. Bar = ~350 μm. Source.

Putting two and two together, one can well imagine that these Thiomargarita have a dimorphic life cycle. Suppose the elongated attached cells reproduce by budding, and the freed cells later attach to a substrate and elongate, thus completing the cycle. If so, then the attached elongated cells and at least some of the free-living spherical cells are simply different stages in the life cycle of the same species. Something like a giant Caulobacter! Although the evidence is not yet watertight, this hypothesis seems likely to me. These researchers not only observed the budding process, but also saw that the attached cells spanned the entire spectrum of expected shapes from nearly spherical, recently-landed cells to slightly elongated to fully elongated and budding. Lots of questions remain. So far, there is no way to estimate what proportion of the solitary cells arose by budding or what portion of the generation time is spent being planktonic versus attached.

If the planktonic and attached forms are the same species, their 16S rRNA gene sequences would be identical. To test this, the researchers isolated individual cells of various shapes. They then PCRed the 16S rRNA genes in these single cells using primers designed for Thiomargarita-related organisms. When they sequenced the PCR products, they found that one planktonic cell and one attached cell had essentially identical 16S sequences. (COS008 and COS014 shared 99.4% identity, which is within the margin of error.) When they built a phylogenetic tree that also included other Thiomargarita spp., they found that the various Thiomargarita-like cells collected from Costa Rica were placed in at least three distinct clusters. Most of them are related to previously-known Thiomargarita spp., but two (COS001 and COS016) sit on their own separate branches.

Phylogenetic tree of 16S rRNA gene sequences of sulfide-oxidizing γ-proteobacteria. Grey = sequences of different morphotypes from Costa Rica (COS) and Namibia (NAM). For each cell sequenced in this study, the morphology and diameter are included. Bar = ~10% sequence divergence. Source.

These same attached forms have also been observed at methane seeps off the coast of Oregon. Why are elongated Thiomargarita-like cells found around these seeps but not, so far, elsewhere? The authors suggest that elongation may be a strategy to enhance phosphate uptake, as had been previously posited for the α-proteobacterium Caulobacter crescentus. This hypothesis assumes that in order to maintain a certain amount of cytoplasm, Thiomargarita needs both a large enough surface area for  phosphate uptake and a large enough vacuole for nitrate storage. One way to have both is by elongating. Another way to achieve the same result—larger surface area for the same nitrate storage capacity—is by producing smaller cells, the option used by the reductively-dividing clusters.

And here the story rests. Answering the pending questions won’t be easy, as the organisms cannot be cultured and collecting samples requires a deep-ocean research submersible. However, the bottom of the sea is a never-ending source of surprises and exploring the deeps is guaranteed to yield yet more amazing new findings.

Bailey JV, Salman V, Rouse GW, Schulz-Vogt HN, Levin LA, & Orphan VJ (2011). Dimorphism in methane seep-dwelling ecotypes of the largest known bacteria. The ISME Journal, 5 (12), 1926-35 PMID: 21697959

The Paenibacillus Moving Company

by Elio

Enlightenment, a bacterial colony. Displayed in the
Esher Ben-Jacob online art gallery. Source.

Microbes get around. They can be carried by the wind, by insects, or by water currents, sometimes across large distances, sometimes from one grain of soil to the next. Some bacteria contribute to their own dispersal by their motility or, rarely, one may think, by the motility of other microbes. It’s hard to generalize here because there are just too many variables, too many conditions where microbes are on the move. But this business can be pure fun. So it’s with pleasure that I read about a delightful account of how bacteria can transport fungal spores to the benefit of both.

But first a little background, both microbial and personal. Some bacteria, when placed on an agar surface, do not stay put but spread out from the point of inoculation. Certain ones, such as Bacillus mycoides, do it simply by extending their long filaments, but others do it by moving on the agar surface. There are several ways to move along, either with flagella (a process called swarming) or without them (e.g., gliding or twitching). Swarming, whether in Gram-positives like certain Bacillus species or in Gram-negatives such as Proteus, is a communal activity. Single cells don't swarm, aggregates of several cells do. What you see under the microscope are rafts of bacteria arranged side by side, moving along a path that is sometimes regular, sometimes not. To download a movie of a ‘raft’ of ceils swarming together, click here (or to go to the web page where you can select additional file 4, click here). The speed of movement across the agar surface is pretty amazing, about 180 µm/min or 10 mm/h. This means that if you place such a bacterium in the center of a 14 cm Petri dish, it will reach the edge in about seven hours. When such a swarm has covered a certain distance, the cells either stop moving, as in the case of Proteus, or make round disc-like colonies that have the odd ability to rotate. For a movie of a ‘colony’ of cells swarming together, click here (or to go to the web page where you can select additional file 2, click here). The speed at which this rotation happens is also quite fast, one revolution in about 10 seconds. Towards the end of my career, but while I still had a lab, my collaborator Dana Boyd and I played around with these organisms. This was the last time that I worked at the bench, so I quite cherish this topic.

A typical colonial pattern generated by P. vortex when grown on 2.25%
(w/v) agar with 2% (w/v) peptone in a 9 cm Petri dish. (A) Whole colony
view. Each vortex (the condensed group of bacteria, the bright dots) is
composed of many cells that swarm collectively around their common
center at about 10 μm/s. (B) An individual vortex. The diameter of the
vortex is 75 μm. Source.

Peering at bacteria that are swarming is a game most anyone can play. If you have access to a Petri dish with agar in it, take a few grains of almost any soil and place them in the center. Within six hours or so, you will see that among the many small colonies on the surface there will be some that moved away from the inoculum site. What you will see are tracks with ‘colonies’ at the end. Most likely, you are now looking at Paenibacillus, the organism I’m featuring here.

Paenibacillus, once merely known as Bacillus (the current name means almost Bacillus), of which there are many species, is one of the champion swarmers that has puzzled microbiologists for over 100 years. So, you ask, why do they swarm? Hmm, it would seem intuitively obvious that they must be scavenging for food. Not so fast. The swarms do not exhibit chemotaxis or any other preference for needed nutrients, as some other bacteria do. We found that our strains could swarm on agar containing just phosphate buffer, period. For good measure, we added chloramphenicol, to which these bugs were sensitive, and that didn't impair their travels. At no time did we see the swarms move preferentially towards a place on the plate where we had put any of a variety of nutrients.

In our efforts to figure out what this is all about, we confirmed something that had been known, namely that the bacteria could carry around other bacteria, such as cocci. To take this to the limit, we used 1 µm diameter latex particles and, guess what, they were spread around just like the bacteria themselves. These particles seemed to be pushed along, either at the head of a raft or trapped within it. So at that point we started to think that swarming could be used for interactions with other organisms, possibly to carry along species that could furnish the swarmers with food in certain fallow environments. We never demonstrated this, although it seems as plausible today as then.

However, to my satisfaction, others are having a longer and more productive look. In particular, microbiologist Colin Ingham teamed up with physicist Esher Ben-Jacob and colleagues Oren Kalisman, and Alin Finkelstein to ask probing questions of these bacteria. Not only that, but they are having fun with the patterns that bacteria can form on agar as witnessed by a gallery of sensational pictures. In a recent paper, these investigators showed that these bacteria are able to move the spores of a fungus, Aspergillus fumigatus. This fungus is a common soil organism known to cause disease in immunocompromised patients. The fungal spores are not motile, thus dependent on water or air currents for dispersion. It turns out that if you mix these spores with cells of a species of Paenibacillus called P. vortex, the spores are moved along for quite a distance, at the same rate as the bacteria. After suitable incubation, fungal colonies appear all over the plate. It’s up to you to imagine the practical implications of these findings.

Volga Boatmen, by Ilya Repin. Source.

These microscopic ferrymen can haul quite a cargo. It can consist not just of individual spores but also spore aggregates 25 µm across (each spore is about 3 µm in length). This reminds one of ants that can carry up to one hundred times their body weight. It gets better. These bacteria can even impel the fungal spores across an area on the agar impregnated with an antifungal growth-inhibitory compound, a veritable minefield.

In searching for the mechanism involved, the authors found that not all fungal spores can be so translocated. Spores of even some close relatives of A. fumigatus do not play the game but stay put on the agar. Also, germinating spores are not transported efficiently. Under the electron microscope, spores being carried are seen surrounded by bacterial flagella. And, sure enough, adding purified flagella inhibited their transport. This suggests the presence of receptors for flagella on the surface of certain spores and not others. So, are there two different mechanisms involved, one for non-specific particles such as latex beads, another specific for certain cargoes? Does this have anything to do with the size of the object being moved, the larger ones requiring chemical recognition by the bacteria?

Bacteria crossing a canyon in the Petri dish along
natural bridge of fungal mycelia (top, courtesy of Colin
Ingham), much like animals crossing a canyon in Nepal
on a man-made bridge (bottom, courtesy of Aya Ben-
Yakov). Source.

It is easy to see what's in it for the fungus. It gets translocated, and thus is dispersed to new sites. But what's in it for the bacteria? The investigators did a simple but clever experiment: they cut a slit in the agar a half millimeter wide. The bacteria could not cross it alone, but the fungi had no problem spanning the gap with their hyphal threads. And when both bacteria and fungi were present, guess what? On the other side they now found bacteria that had done a high wire act on the fungal tightrope. In other systems, it has been shown that bacteria make biofilms on the surface of hyphae so, in a way, this was to be expected.

Not only do these bacteria move on agar at a fine clip, but they do it even under conditions of starvation. As I mentioned already, in my lab we saw swarming taking place at normal speeds on agar that contained only phosphate buffer. No added food. They seem to want to move at all costs, consuming precious metabolic reserves in the process. Swarming is their top physiological priority. So one would guess that this is a property that has been selected for in a big way during evolution. Whatever the purpose, we may have been premature in ruling out some kind of chemotaxis. In the supplemental material to one Ben-Jacob paper (To see the movie, click here, or to go to the web page where you can select additional file 5, click here), there is an indication that swarms of bacteria move towards extracellular material left in the trails, although this may not be for nutritional reasons

Distribution of the relative Social IQ scores of 502 bacteria. Green indicates bacterial strains
that belong to the Paenibacillus genus. Source.

Now a final word about Paenibacillus and its genome. It turns out that it’s one smart bug, in fact, brilliant by one criterion. Ben-Jacob scored the genomes of many bacterial species for the number of genes potentially involved in social behaviors. He proposed a bacterial Social IQ scale, which he describes as: a quantitative score.… to assess the genome potential of bacteria to conduct successful cooperative and adaptable behaviors (or social behaviors) in complex adverse environments…. The score is based on the number of genes which afford bacteria abilities to communicate and process environmental information (Two-component system and transcription factor genes), to make decisions and to synthesize offensive (toxic) and defensive (neutralizing) agents as needed during chemical warfare with other microorganisms. Now for the punch line: Three bacteria species stand out with significantly high Social-IQ score among all sequenced bacteria,—over 3 standard deviations higher than average, indicating a capacity for exceptionally brilliant social skills). Notably, all these species belong to the same bacteria genus—the Paenibacillus…^.

Ingham CJ, Kalisman O, Finkelshtein A, & Ben-Jacob E (2011). Mutually facilitated dispersal between the nonmotile fungus Aspergillus fumigatus and the swarming bacterium Paenibacillus vortex. Proceedings of the National Academy of Sciences USA, 108(49): 19731-6. PMID: 22106274.

Geobacter: Microbial Superhero

by Suzanne Winter

Iron-breathing microbes, Geobacter. © Derek Lovley
Kelly Nevin & Ben Barnhart, University of Massa-
chusetts. Source.

If the power of Superman resided solely in his supernatural abilities, then Bruce Wayne’s Batman would never have been able to compete on his level. But when the other factors that superheroes depend upon are accounted for—sidekicks, spandex, sarcasm—both Superman and Batman can claim success in the world of do-goodery and hunky haircuts. In other words, the strength and effectiveness of an individual’s power often depends entirely on the creative use of raw materials.

This reality is mirrored in the microbial realm: organisms compete to occupy and dominate specific niches through adaptation and natural selection, and it’s the ones that play by an entirely different set of rules that may have the possibility to change the world.

Notably, species that have evolved innovative and, subjectively, weird methods of living have long intrigued scientists with their survival abilities and preferences. Consider the fascination with the extremophiles in the hot springs at Yellowstone National Park that led to the isolation of Taq DNA polymerase from Thermus aquaticus, surely one of the most important enzymes in the molecular biology lab. And while many microbes follow the well-studied route of using oxygen as a final electron receptor, researchers are increasingly looking at Geobacter species that use iron oxides as the final electron receptor in order to uncover the secrets enigmas of environmental restoration, energy harvesting, and the creation of the world.

Some Like it Hot

by S. Marvin Friedman

Red coloration on rocks near Naples, Italy, produced by the
hyperthermophile Sulfolobus solfataricus. Source.

How can thermophilic bacteria not only survive, but actually proliferate, at elevated temperatures that would be lethal to all other forms of life? After extensive research during the past five decades, this question has been answered in a general way, but the molecular basis for this unusual capability has not been clearly resolved. Thermophiles [I use this term to include both thermophiles (optimal growth temperatures of 50-70 °C) and hyperthermophiles (optimal growth temperatures >80 °C)] synthesize intrinsically thermostable cellular components and/or extrinsic stabilizing factors (chaperonins and polyamines, for example).

Most proteins isolated from thermophiles are thermostable and the mechanisms underlying this property have been extensively studied. These investigations have their roots in the pioneering work on the heat stability of hemoglobin and ferredoxin carried out by Perutz in 1975. Some of the strategies reported to bring about protein thermostability include higher levels of charged amino acids on the protein surface that promote ionic interactions, amino acid preferences, hydrophobic cores, aliphatic side chains, disulfide bridges, and solute accumulation. It is obvious from these studies that a universal mechanism to achieve protein thermostability does not exist. The complexity of this problem is highlighted by differences that appear to be in play for multimeric proteins versus single polypeptide chains, for soluble proteins versus membrane proteins, and for proteins from thermophiles versus proteins from hyperthermophiles.

Commuting to Work

by Elio

A tube core (8 cm diameter) collected from a Thioploca
bacterial mat. The mat is approximately 1 cm thick.
Photo by Lisa Levin. Source.

An underwater microbial mat has been found in fairly shallow waters off the coast of Chile and, according to headlines (click here and here), it’s the size of Greece, or about 132,000 km² (or for us norte-americanos, about the size of Alabama). These communities of sulfide-oxidizing bacteria have been known for some time, but their attention has been highlighted by the recent version of the Census of Marine Life. In fact, they were discovered in 1963 by the oceanographer and microbiologist Victor Gallardo of Chile’s University of Concepción. Scientists may not have known much about these huge mats much earlier on, but the local fishermen sure did and called them estopa, Spanish for burlap or unwashed wool or flax.

What the mats look like on close-up (swaying in the
current?). Source.

Aficionados of the giant sulfur-oxidizing bacterium Thiomargarita namibiensis and other bacterial gargantuas likely include Thioploca, the occupants of these mats, in their catalog of microbial marvels. This is a genus of gliding, filamentous bacteria that live in aquatic sediments where they face the same problem as Thiomargarita, namely how to hook up their fuel (sulfides) with their final electron acceptors (nitrates). (For details of their metabolism, see a recent paper.)

An Inactive Mine Provides Active Opportunities

Acid mine drainage in Spring Creek down-
stream from the Richmond Mine, part of
the Iron Mountain Mine Superfund Site
nine miles northwest of Redding, Calif.
Microbes inside the mine eat pyrite─fool's
gold─to produce sulfuric acid, creating the
most acidic groundwater ever measured.
Spring Creek flows eventually into the
Sacramento River. (UC─Berkeley) Source.

by Elio

“...a riddle, wrapped in a mystery,
inside an enigma...”
                                  Winston Churchill

Metagenomics is a fine tool indeed for surveying a microbial community in concert, treating both the cultured and uncultured equally. When the sample studied is rich in microbial variety, as often is the case, the pieces of genomes can be reluctant to reveal the genetic heritage of whole microbes. But there are a few particular environments that are dominated by a handful of species at most, and here this approach allows the reconstruction of complete genomes. That is the case with the acid mine drainage from mineral or coal mines. When mining ceases, all hell can break loose (anthropocentrically speaking). Microbes oxidize sulfides such as pyrite (iron sulfide) into sulfuric acid, which in turn solubilizes iron, copper, arsenic, silver, gold, and other heavy metals. Water no longer being pumped from the mine, this gemish of minerals emerges from seeps and other openings to become a highly toxic, low pH stream that eventually pollutes larger bodies of water. But for some bacteria and archaea, this is a juicy place to live and thrive.

The Uncultured Bacteria

by Kim Lewis

Fig. 1. "The Great Plate Count Anomaly."

The majority of bacteria will not grow on nutrient medium in the lab. The basic experiment is simple: take a sample from the environment, such as marine sediment or soil, mix with water, vortex, allow it to settle, dilute supernatant and take two droplets. Plate one on a Petri dish with LB medium, and place the other on a microscope slide (adding a dye such as DAPI helps). Count the number of cells under the microscope and the number of colonies on the Petri dish – the result will be “The Great Plate Count Anomaly.” About 100 times more cells will be observed microscopically than colonies counted on the Petri dish (Fig. 1). This simple result is one of the most profound puzzles in microbiology, and one of the most significant unsolved questions in biology. Indeed, microorganisms probably make up the bulk of the total biodiversity of species on the planet, but we do not have access to the vast majority of them. Importantly, most Divisions—the largest taxonomic units—do not have a single cultivable representative, and we know of their existence only from 16S rDNA isolated directly from the environment.

There are two basic approaches to solving a problem, and one of them is to decide that it does not exist. It has been suggested on the pages of Nature and Microbe that the anomaly only exists in our minds and results from the insufficient number of microbiologists with a “green thumb” willing to tinker with growth conditions. However, the anomaly has existed for over 100 years, and tinkering by generations of scientists produced only minor improvements. A serious effort was mounted by several groups to culture representatives from the ubiquitous TM7 division, for example, but produced no results.

Everyone Rowing in the Same Direction

by Merry

Source.

Is there such a thing as an obligatorily multicellular prokaryote? We presented a case for their existence before, one that fueled our evolutionary imaginations. Unlike the myxobacteria, for example, which have both unicellular and multicellular stages, some magnetotactic bacteria appeared to be multicellular throughout their lives. Their multicellular coordination is apparent from their complex swimming behavior, their synchronous cell division, and their subsequent division into two equal multicellular spheres. Intriguing they are, but they could easily be relegated onto a shelf for microbial oddities—just one small group within the δ-proteobacteria, magnetotactic and restricted to saline environments.

Differential interference contrast (DIC) light micro-
graph of a disaggregated nMMP. Source.

Now a recent paper announces the finding of a new subgroup within that multicellular clade. These new critters have a similar life cycle and morphology. They, too, are sulfate-reducers, but they are found in low-saline, nonmarine aquatic environments, and they are not magnetotactic—thus called non-Magnetotactic Multicellular Prokaryotes or nMMPs. Although they don't navigate by compass, they do exhibit active negative phototaxis—the first δ-proteobacteria known to do so. This ability was useful for the researchers; they set up a "light racetrack" in a capillary tube to concentrate these unculturable bacteria at one end of the tube. Is phototaxis useful for the nMMPs?

State Microbes

by Elio

Not long ago, I was interviewed twice (click here and here) by Michelle Norris of National Public Radio’s All Things Considered regarding the burning issue of state microbes. The first interview was in response to the news that the state of Wisconsin’s State Assembly passed a bill proclaiming Lactococcus lactis as its state microbe. I opined that this would be a most appropriate choice, given the role of this bacterium in making cheese, a matter of obvious importance to Wisconsinites. Alas, the state Senate did not take up the bill, so L. lactis will have to wait (perhaps in a lyophilized state) for future proposals. Michelle proposed that the other states now have the chance to be the first to adopt a state microbe. Listeners sent in their nominations, some of which we discussed during the second interview.

Mentioning the quest for state microbes to microbiologists and non-microbiologists alike usually results in a chuckle. Fair enough: in today’s world, preoccupation with such ostensibly trivial matters may be frivolous. Still, there could be an educational point to this. Kids in each state, when presented with the state microbe, may want to figure out what makes the microbe special and even learn something about microbes in general. (Maybe adults, too!)

The interviews were good fun (the kinship in the names of our respective activities, STC and ATC, was a comfortable point of departure). Michelle was exceedingly friendly and helpful, likewise her off-the-air colleague Melissa Grey (author of All Cakes Considered). Both were eager to delve into matters microbial. Each time the interview lasted some 15 minutes, from which they selected the material that was aired. We chatted in a free and easy manner that I found both relaxed and pleasant.

Here is a list of nominations from NPR listeners and readers of New Scientist, as well as some of our own. Perhaps microbiologists in each state will find it worthwhile to come up with their choices. Those with political connections to state legislators should pay special heed. I omit suggestions of pathogenic agents (with a couple of exceptions), on the supposition that state legislatures would not take kindly to them.

• Alabama: Karenia brevis, a dinoflagellate, aka the Red Tide Alga. A shoo-in if you think of the Crimson Tide. (Jenny Ridings, New Scientist)
• Alaska: The permafrost bacterium Carnobacterium pleistocenum found in 35,000 year-old ice. (Rowan Hooper, news editor, New Scientist)
• Arizona: (1) Thiobacillus ferrooxidans for its role in copper leaching. Arizona is the top copper-producing state in the US. (Elio)
(2) Penicillum for the penicillin it makes, to be used to cure gunshot wounds due to the recent illegal immigrant law. (NPR listener)

• California: (1) Saccharomyces cerevisiae, for its importance in making wine. (Elio) (Also suggested for several other states)
(2) The city of Los Angeles got two nominations for a “city microbe:” Clostridium botulinum, the source of botox. (NPR listener; Rowan Hooper, news editor, New Scientist)

• Florida: (1) Retirement communities in Florida would appreciate the 250-million-year-old Lazarus bacillus Bacillus permians. Note that there is far from universal agreement about the longevity of this bacterium. (Rowan Hooper, news editor, New Scientist)
(2) The Sunshine State can share its ample sunlight and coastal waters with a photosynthetic marine cyanobacterium, e. g., Synechococcus elongatus. (Elio)

• District of Columbia: Cupriavidus metallidurans (formerly Ralstonia metallidurans), the gold mining bug that turns soluble gold into nuggets. They could use it there. See our previous post. (Elio)
• Hawaii: Another state claiming Lactococcus lactis, here fermenting taro into poi. (Merry)
• Indiana: Zymomonas mobilis, a bacterium that produces ethanol very efficiently. Indy 500 cars run on ethanol. (AmoebaMike, New Scientist)
• Iowa: Bradyrhizobium japonicum, a nitrogen fixing symbiont of soybean plants. Iowa is one of the top soybean producers in the US. (Elio)
• Kansas: MRSA, for illustrating evolution in action. (several NPR listeners)
• New Jersey: (1) Streptomyces griseus, the bacterium that makes streptomycin, a pioneer antibiotic discovered at Rutgers University by Selman Waxsman. (Elio)
(2) Sewage methanogenic bacteria, for New Jersey’s famous marshland garbage dumps. (Rowan Hooper, news editor, New Scientist)

• New Mexico: The “indestructible bacterium” Deinococcus radiodurans that probably survived the Trinity A bomb test carried out in New Mexico in 1945. (Rowan Hooper, news editor, New Scientist)
• Nevada: Home of the neon glow in Las Vegas gets the flashing light of Vibrio fischeri. (Rowan Hooper, news editor, New Scientist)
• Rhode Island (1) Epulopiscium fischelsoni, the biggest known bacterium (never mind Thiomargarita) for the smallest state in the Union. (NPR listener)
(2) The nanobacteria (Ed. Note: assuming they exist). (Rowan Hooper, news editor, New Scientist)

• Texas: The oil eating Synthropus may be useful for cleanup of oil spills. (Rowan Hooper, news editor, New Scientist)
• Utah: The salt-loving Haloarcula for the Great Salt Lake. (Rowan Hooper, news editor, New Scientist)
• Virginia: The Epstein Barr virus or kissing bug because “Virginia is for lovers.” (NPR listener)
• Washington: Here they may appreciate the rain-making bacterium Pseudomonas syringae. (Rowan Hooper, news editor, New Scientist)
• Wisconsin: Lactococcus lactis, the essential cheese-maker. (Wisconsin State Assembly)
• Wyoming: Thermus aquaticus, which was isolated from a Yellowstone hot spring and went on to make a great living as the source of the Taq polymerase. (Elio)

Can you think of others? Keep them coming!

When Crenarchaeota Divide, They Multiply

by Jenn Tsau and Suzy Szumowski*

Sulfolobus acidocaldarius, an extreme thermophile occurs in
geothermally-heated acid springs, mud pots and surface soils;
it can withstand temperatures from 60 to 95 ºC, and a pH of
1 to 5. Left: Electron micrograph of a thin section (X85,000);
Right: Fluorescent photomicrograph of cells attached to a
sulfur crystal. Source.

When cells divide, it’s really important that they do so equitably so you don’t end up with some having too much and some too little cell material; the results of either could be deleterious. Therefore, over the billennia that life has been around, mechanisms to carefully divvy up intracellular goodies like DNA and cytoplasm have evolved. You can imagine that interest peaked in those who pay attention to such things when it was found that a group of microbes belonging to the Crenarchaeota lack any of the known cell division machinery. Crenarchaeota are a kind of Archaea that includes species known to survive in extremely hot or cold environments. And when we say extreme, we mean deep arctic-cold and volcano-hot—literally. Other known forms of life have some variant of actin (known as MreB in bacteria) or tubulin (aka FtsZ), which are involved in cell division or maintenance of cell shape. Until late 2008, when a pair of papers was published, no such proteins were found in the crenarchaea and their division remained quite mysterious.

Regardless, these hardy little archaea are getting the job done, one way or the other. It has been known for some time that the Crenarchaeota possess homologs of a system called ESCRT (endosomal sorting complex required for transport). This is an attractive candidate for managing division in these organisms. Why? Because the ESCRT system helps detach daughter from mother cell during cell division in metazoans—such as insects, octopuses, and elephants. So it seemed plausible that these proteins might be helping here as well.