Tartrolons are a group of

boron Boron is a chemical element; it has symbol B and atomic number 5. In its crystalline form it is a brittle, dark, lustrous metalloid; in its amorphous form it is a brown powder. As the lightest element of the boron group it has three ...

-containing

macrolide Macrolides are a class of mostly natural products with a large macrocyclic lactone ring to which one or more deoxy sugars, usually cladinose and desosamine, may be attached. Macrolides belong to the polyketide class of natural products. ...

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

s discovered in 1994 from the culture broth of the

myxobacterium The myxobacteria ("slime bacteria") are a group of bacteria that predominantly live in the soil and feed on insoluble organic substances. The myxobacteria have very large genomes relative to other bacteria, e.g. 9–10 million nucleotides except ...

Sorangium cellulosum ''Sorangium cellulosum'' is a soil-dwelling Gram-negative bacterium of the group myxobacteria. It is motile and shows gliding motility. Under stressful conditions this motility, as in other myxobacteria, the cells congregate to form fruiting b ...

''. Two variants of tartrolons, A and B, were identified. Tartrolon B contains a boron atom, while tartrolon A does not.

Discovery

In a study publishied in 1994, the producing organism,

strain ''So ce 678'', was isolated by a group of German scientists (Dietmar Schummer, Herbert Irschik, Hans Reichenbach, Gerhard Höfle) from a soil sample collected near

Braunschweig Braunschweig () or Brunswick ( ; from Low German , local dialect: ) is a List of cities and towns in Germany, city in Lower Saxony, Germany, north of the Harz Mountains at the farthest navigable point of the river Oker, which connects it to the ...

in 1990, as

antibiotics An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting pathogenic bacteria, bacterial infections, and antibiotic medications are widely used in the therapy ...

of the

group. Synthesis was achieved by

fermentation Fermentation is a type of anaerobic metabolism which harnesses the redox potential of the reactants to make adenosine triphosphate (ATP) and organic end products. Organic molecules, such as glucose or other sugars, are catabolized and reduce ...

in the presence of the adsorber resin XAD-16. Adsorber resin is a type of

synthetic polymer Some familiar household synthetic polymers include: Nylons in textiles and fabrics, Teflon in non-stick pans, Bakelite for electrical switches, polyvinyl chloride (PVC) in pipes, etc. The common PET bottles are made of a synthetic polymer, polyet ...

used to selectively extract and purify target molecules from solutions. These findings were confirmed by a subsequent study, in 1995, where the strain was grown on a medium containing

potato starch Potato starch is starch extracted from potatoes. The cells of the root tubers of the potato plant contain leucoplasts (starch grains). To extract the starch, the potatoes are crushed, and the starch grains are released from the destroyed cells. Th ...

, yeast extract, defatted soja meal, glucose-H₂O, MgSO₄·7H₂O, CaCl₂-2H₂O and Na-Fe(III)-EDTA at pH 7.2. To isolate greater quantities of tartrolons for research purposes or potential applications in medicine, the strain was cultivated in a

bioreactor A bioreactor is any manufactured device or system that supports a biologically active environment. In one case, a bioreactor is a vessel in which a chemical reaction, chemical process is carried out which involves organisms or biochemistry, biochem ...

. Cultivation was started with an inoculum grown in

Erlenmeyer flask An Erlenmeyer flask, also known as a conical flask (British English) or a titration flask, is a type of laboratory flask with a flat bottom, a conical body, and a cylindrical neck. It is named after the German chemist Emil Erlenmeyer (1825–190 ...

s under shaking at 30°C with an aeration rate of 0.15 m³ air per hour and a stirrer speed of 150

RPM Revolutions per minute (abbreviated rpm, RPM, rev/min, r/min, or r⋅min−1) is a unit of rotational speed (or rotational frequency) for rotating machines. One revolution per minute is equivalent to hertz. Standards ISO 80000-3:2019 def ...

Laboratory synthesis

The synthesis and regulation of tartrolons are influenced by the presence or absence of glass flasks during cultivation or by adding

sodium tetraborate The BORAX Experiments were a series of safety experiments on boiling water reactor, boiling water nuclear reactors conducted by Argonne National Laboratory in the 1950s and 1960s at the National Reactor Testing Station in eastern Idaho.

to the culture medium. When not exposed to glass or sodium tetraborate supplementation is absent, tartrolon A is predominantly produced; otherwise, tartrolon B becomes the main product.

Biological properties

Tartrolons have been found to inhibit

Gram-positive bacteria In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain ...

similar to other related boron-containing antibiotics like

boromycin Boromycin is a bacteriocidal polyether- macrolide antibiotic. It was initially isolated from the '' Streptomyces antibioticus'', and is notable for being the first natural product found to contain the element boron. It is effective against most ...

and aplasmomycin, as their boron binding regions are identical. Tartrolons also show toxicity towards mammalian cell cultures.

Potential applications

The antimicrobial properties of tartrolons indicate they could be investigated as antibiotics to combat bacterial infections. However, more comprehensive studies are needed to ascertain their efficacy, safety, mechanism of action, and other potential medicinal uses; whether tartrolons possess selectivity towards enzymes or interference with energy delivery and membrane integrity; and whether tartrolons have any biological roles beyond their antibiotic activity in nature. One potential application of tartrolons is the study of species such as ''

Listeria monocytogenes ''Listeria monocytogenes'' is the species of pathogenic bacteria that causes the infection listeriosis. It is a facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can grow and reproduce inside the ho ...

''. Listeria monocytogenes is a bacterium that can cause the infectious disease known as listeriosis. It is considered a foodborne pathogen and poses a significant risk to human health. Listeriosis primarily affects individuals with weakened immune systems, pregnant women, newborns, and the elderly. Listeria monocytogenes, as a bacterium, is present in diverse habitats where tartrolons are found. As such, it is important to explore the potential application of tartrolons in suppressing Listeria monocytogenes or other related pathogens. The antimicrobial properties exhibited by tartrolon B and its induction of the timABR locus, which contributes to resistance against tartrolons in Listeria monocytogenes, suggest their potential for antibacterial activities. However, additional studies would be needed to determine the specific effectiveness and mechanisms involved in controlling Listeria monocytogenes with tartrolons. Studying tartrolons may shed light on how pathogens like Listeria adapt to diverse habitats and survive within their ecological niches despite the presence of antimicrobial compounds produced by other microorganisms. Understanding these mechanisms could aid in developing strategies to control or prevent infections caused by Listeria or related pathogens. Besides the application in medicine, studying the interaction between Listeria monocytogenes and tartrolons may expose the broader ecological dynamics between bacteria in natural reservoirs such as soil and marine environments where both pathogenic and non-pathogenic species coexist. This knowledge can contribute to understanding of

microbial ecology Microbial ecology (or environmental microbiology) is a discipline where the interaction of Microorganism, microorganisms and their environment are studied. Microorganisms are known to have important and harmful ecological relationships within t ...

and can help design interventions to manage bacterial populations in agricultural settings or food production facilities where contamination with Listeria can occur.

References

{{reflist Antibiotics Boron