Donald B. Stierle

The Berkeleyamides, Amides from the Acid Lake Fungus Penicillum rubrum

We previously reported several novel bioactive hybrid polyketide-terpenoid metabolites from a deep water Penicillium rubrum isolated from Berkeley Pit Lake, Butte, Montana. In this paper we report the structures of four new amides, berkeleyamides A-D (1, 4, 5, 7), isolated from extracts of this fungus. The structures of these compounds were deduced by analysis of NMR data, chemical derivatization, and comparison of their spectroscopic data to those of known compounds.

Pseudomonic acid derivatives from a marine bacterium

The spongeDarwinella rosacea was found to harbor a host of marine microorganisms. One of these bacteria was identified as a marineAlteromonas species. The organic extract of this bacterium was antimicrobial, and the activity was traced to two novel pseudomonic acid derivatives1 and7. The structures of these compounds were elucidated by interpretation of the spectral data and extensive use of 2-dimensional NMR techniques and NOE studies on the parent compounds and the acetate derivatives2 and8.

Berkeleyones and related meroterpenes from a deep water acid mine waste fungus that inhibit the production of interleukin 1-β from induced inflammasomes.

The Berkeley Pit, an acid mine waste lake, is a source of extremophilic microorganisms that produce interesting bioactive compounds. We have previously reported the isolation of berkeleydione (1), berkeleytrione (2), the berkeleyacetals, and the berkeleyamides from the Pit Lake fungus Penicillium rubrum. In this paper we report the isolation and characterization of berkeleyones A-C (4, 5, and 7) as well as previously described preaustinoid A (3) and A1(6) from this same fungus. These compounds were evaluated as inhibitors of the signaling enzyme caspase-1 and as potential inhibitors of interleukin 1-β production by inflammasomes in induced THP-1 cell line assays.

Caspase-1 inhibitors from an extremophilic fungus that target specific leukemia cell lines.

Berkeley Pit Lake, Butte, Montana, is a 540 m deep abandoned open-pit copper mine filled with over 140 billion liters of acidic, metal-sulfate-contaminated water. This harsh environment has yielded several microorganisms that produce interesting biologically active compounds. Several polyketide metabolites including the new berkazaphilones A (1) and B (2) and octadienoic acid derivatives berkedienoic acid (13) and berkedienolactone (15), as well as previously reported azaphilone 4, vermistatin (6), dihydrovermistatin (7), penisimplicissin (8), aldehyde 9, and methylparaconic acid (11), were isolated from a culture broth of Penicillium rubrum taken from a depth of 270 m. The structures of these compounds were deduced by interpretation of spectroscopic data. The compounds were isolated either for their inhibition of the signal transduction enzyme caspase-1 or because of their structural similarity to these inhibitors. Selected compounds were further evaluated for their ability to inhibit interleukin-1β production by inflammasomes in induced THP-1 cells. Berkazaphilones B (2) and C (4) and vermistatin analogue penisimplicissin (8) exhibited selective activity against leukemia cancer cell lines in the National Cancer Institute 60 human cell line assay.

Caspase-1 and -3 Inhibiting Drimane Sesquiterpenoids from the Extremophilic Fungus Penicillium solitum

Two new drimane sesquiterpene lactones and one new tricarboxylic acid derivative were isolated from the Berkeley Pit extremophilic fungus Penicillium solitum. The structures of these compounds were deduced by spectroscopic analysis. Berkedrimanes A and B inhibited the signal transduction enzymes caspase-1 and caspase-3 and mitigated the production of interleukin 1-β in the induced THP-1 (pro-monocytic leukemia cell line) assay.

Bioprospecting in the Berkeley pit: Bio active metabolites from acid mine waste extremophiles

Abstract The Berkeley Pit Lake system in Butte, Montana is part of the largest EPA Superfiind site in North America. It includes Berkeley Pit Lake, an abandoned open-pit copper mine, 1300 feet deep and one mile across. During its thirty years of operation the Pit and surrounding deep shaft mines were dewatered through constant pumping. On Earth Day 1982 the pumps were turned off for the last time, and the Pit began to evolve into an acid mine waste lake. As infiltrating ground water continually seeps into the Pit, rich veins of pyrite and other minerals dissolve, generating acid in the process. There are currently 30 billion gallons of water in the Pit, with an inflow rate of 4 million gallons/day. The water is acidic (pH 2.5 - 2.7) and contaminated with high concentrations of metal sulfates including iron, copper, aluminum, cadmium and zinc. Unfortunately, the Pit Lake system sits at the headwaters of the Clark Fork River, a major tributary of the Columbia River. If the water rises another 200 feet, it will reach the critical overflow level. At the current rate of rise, the critical level will be reached in approximately ten years. Although the chemical dynamics and possible remediation strategies of the Pit Lake have been studied for twenty years, the microbial ecology was neglected. With its low pH and high metal content, it was considered too toxic to support life. Since 1995, however, with colleague Grant Mitman, we have isolated over sixty fungi, protists, algae, protozoans and bacteria. Although conditions within the Pit Lake System are toxic for “normal” aquatic biota, these same conditions represent an ideal environment for extremophiles. This hostile environment may also select for new species that produce novel secondary metabolites. It can be a challenge isolating and culturing these extremophiles, but it is the unique challenge of drug discovery to find methods for targeting the bioactive components in these organisms.

Terpenoid and flavone constituents of Polemonium viscosum

Abstract The chemical investigation of Polemonium viscosum yielded several new diterpenes with labdane and pimarane skeletons, a new flavone and two new monoterpene glycosides. The absolute configuration of akhardiol is established by X-ray structure determination of the O-bromobenzoate derivative.

Cyclobutadieneiron tricarbonyl carboxylic acids: Synthesis and acidity

Abstract Two carboxylic acid derivatives of the cyclobutadieneiron tricarbonyl (I) system have been synthesized and their p K a values determined. It appears that I tends to be electron withdrawing by induction and electron releasing by resonance.

Azaphilones from an Acid Mine Extremophile Strain of a Pleurostomophora sp.

An extremophilic fungus identified as a Pleurostomophora sp. was isolated from the Berkeley Pit, an acid mine waste lake. When grown in liquid culture, the fungus produced berkchaetoazaphilones A-C (1, 2, and 5), the red pigment berkchaetorubramine (6), and the known compound 4-(hydroxymethyl)quinoline. These compounds were evaluated as inhibitors of matrix metalloproteinase-3, caspase-1, and proinflammatory cytokine production in induced THP-1 cells. Berkchaetoazaphilone B (2) inhibited IL-1β, TNFα, and IL-6 production in the induced inflammasome assay and was cytotoxic toward human retinoblastoma cell line Y79 (IC50 = 1.1 μM), leukemia cell lines CCRF-CEM and SR, and the melanoma cell line LOX IMVI (IC50 = 10 μM).

CB2 receptors regulate natural killer cells that limit allergic airway inflammation in a murine model of asthma.

Allergic asthma is a chronic airway inflammatory disease involving the complementary actions of innate and adaptive immune responses. Endogenously generated cannabinoids acting via CB2 receptors play important roles in both homeostatic and inflammatory processes. However, the contribution of CB2‐acting eicosanoids to the innate events preceding sensitization to the common house dust mite (HDM) allergen remains to be elucidated. We investigated the role of CB2 activation during allergen‐induced pulmonary inflammation and natural killer (NK) cell effector function.