Structure elucidation of a new natural diketopiperazine from a Microbispora aerata strain isolated from Livingston Island, Antarctica.

A new natural diketopiperazine (1) was obtained from the culture broth of Microbispora aerata strain imbas-11A, isolated from penguin excrements collected on the Antarctic Livingston Island. Compound 1 was purified consecutively by solvent extraction, silica gel column chromatography and preparative HPLC. The structure of the compound was elucidated by 1D and 2D NMR experiments and mass spectrometric investigations.

Molecular structural studies of lichen substances with antimicrobial, antiproliferative, and cytotoxic effects from Parmelia subrudecta.

Lecanoric acid (1), orsellinic acid methyl ester (2), orcinol (3), and usnic acid (4) were isolated from the lichen Parmelia subrudecta, collected on Palma of the Canary Islands, Spain. Compounds 1, 2, 3, and 4 were purified by solvent extraction, silica gel column chromatography, and preparative high-performance liquid chromatography (HPLC) consecutively. The structures of the four compounds were elucidated by one- and two-dimensional nuclear magnetic resonance (NMR) experiments and mass spectrometric investigations.

Comparison of the phytotoxic effects of usnic acid on cultures of free-living alga Scenedesmus quadricauda and aposymbiotically grown lichen photobiont Trebouxia erici.

The phytotoxic effects of the lichen secondary metabolite-usnic acid on cultures of free living alga-Scenedesmus quadricauda (UTEX 76) and aposymbiotically grown lichen photobiont Trebouxia erici (UTEX 911) were assessed. We found a relatively strong inhibition effect of usnic acid on the growth of alga Scenedesmus, accompanied by an increase of cell size, an alteration of assimilation pigment composition, followed by strong degradation of chlorophyll a, a decrease of chlorophyll a fluorescence, and an increase of reactive oxygen species in the cells. The content of soluble proteins remained a stable parameter.

Isolation and identification of alpha,alpha-trehalose and glycerol from an arctic psychrotolerant Streptomyces sp. SB9 and their possible role in the strain's survival.

Streptomyces sp. strain SB9 was isolated from perm frost soil samples in Spitsbergen, Arctic Ocean; it grows in a temperature range between 4 degrees C and 28 degrees C. During the survey of biologically active metabolites biosynthesized by this strain, significant amounts of alpha,alpha-trehalose (1) and glycerol (2) were detected.

Sanionins: anti-inflammatory and antibacterial agents with weak cytotoxicity from the Antarctic moss Sanionia georgico-uncinata.

Sanionins A (1) and B (2) were isolated from the moss Sanionia georgico-uncinata, collected on the Antarctic Livingston Island. The compounds 1 and 2 were purified by solvent extraction, silica gel column chromatography, and preparative HPLC, consecutively. The structures of the both compounds were elucidated by 1D and 2D NMR experiments and mass spectrometric investigations.

Microbiaeratin, a new natural indole alkaloid from a Microbispora aerata strain, isolated from Livingston Island, Antarctica.

A new sulphur-containing natural alkaloid named microbiaeratin (1a) was isolated, together with the known microbiaeratinin (2, bacillamide) from the culture filtrate of Microbispora aerata strain IMBAS-11A. The organism was isolated from penguin excrements collected on the Antarctic Livingston Island. The structure was elucidated by one- and two-dimensional NMR experiments and mass spectrometric investigations.

Diphenylether and macrotriolides occurring in a fungal isolate from the antarctic lichen Neuropogon.

The fungus, Tritirachium sp. HKI 0317, was isolated from the Antarctic lichen Neuropogon sp. Fermentation of this strain, extraction of the culture broth, and preparative separation of produced compounds furnished 4-carboxy-5,5'-dihydroxy-3,3'-dimethyldiphenylether (1), macrosphelide A (2), and macrosphelide J (3).