Compactin?a review

The biosynthetic logic and enzymatic machinery of approved fungi-derived pharmaceuticals and agricultural biopesticides

Covering: 2000 to 2023The kingdom Fungi has become a remarkably valuable source of structurally complex natural products (NPs) with diverse bioactivities. Since the revolutionary discovery and application of the antibiotic penicillin from Penicillium, a number of fungi-derived NPs have been developed and approved into pharmaceuticals and pesticide agents using traditional "activity-guided" approaches. Although emerging genome mining algorithms and surrogate expression hosts have brought revolutionary approaches to NP discovery, the time and costs involved in developing these into new drugs can still be prohibitively high. Therefore, it is essential to maximize the utility of existing drugs by rational design and systematic production of new chemical structures based on these drugs by synthetic biology. To this purpose, there have been great advances in characterizing the diversified biosynthetic gene clusters associated with the well-known drugs and in understanding the biosynthesis logic mechanisms and enzymatic transformation processes involved in their production. We describe advances made in the heterogeneous reconstruction of complex NP scaffolds using fungal polyketide synthases (PKSs), non-ribosomal peptide synthetases (NRPSs), PKS/NRPS hybrids, terpenoids, and indole alkaloids and also discuss mechanistic insights into metabolic engineering, pathway reprogramming, and cell factory development. Moreover, we suggest pathways for expanding access to the fungal chemical repertoire by biosynthesis of representative family members via common platform intermediates and through the rational manipulation of natural biosynthetic machineries for drug discovery.

Penisimplicins A and B: Novel Polyketide-Peptide Hybrid Alkaloids from the Fungus Penicillium simplicissimum JXCC5

In this study, two previously undescribed nitrogen-containing compounds, penisimplicins A (1) and B (2), were isolated from Penicillium simplicissimum JXCC5. The structures of 1 and 2 were elucidated on the basis of comprehensive spectroscopic data analysis, including 1D and 2D NMR and HRESIMS data. The absolute configuration of 2 was determined by Marfey's method, ECD calculation, and DP4+ analysis. Both structures of 1 and 2 feature an unprecedented manner of amino acid-derivatives attaching to a polyketide moiety by C-C bond. The postulated biosynthetic pathways for 1 and 2 were discussed. Additionally, compound 1 exhibited significant acetylcholinesterase inhibitory activity, with IC50 values of 6.35 μM.

Statins-From Fungi to Pharmacy

Statins have been used in the treatment of hyperlipidemia, both as monotherapy and in combination therapy. Natural fermentation processes of fungi such as Monascus spp., Penicillium spp., Aspergillus terreus, and Pleurotus ostreatus have given rise to natural statins. Compactin (mevastatin), the original naturally occurring statin, is the primary biotransformation substrate in the manufacturing process of marketed drugs. Statins are classified into natural, semi-synthetic derivatives of natural statins, and synthetic ones. Synthetic statins differ from natural statins in their structural composition, with the only common feature being the HMG-CoA-like moiety responsible for suppressing HMG-CoA reductase. Statins do not differ significantly regarding their pleiotropic and adverse effects, but their characteristics depend on their pharmacokinetic parameters and chemical properties. This paper focuses on describing the processes of obtaining natural statins, detailing the pharmacokinetics of available statins, divided into natural and synthetic, and indicating their pleiotropic effects.

Tag and Snag: A New Platform for Bioactive Natural Product Screening from Mixtures

Natural products provide an unparalleled diversity of small molecules to fuel drug screening efforts, but deconvoluting the pharmacological activity of natural product mixtures to identify key bioactive compounds remains a vexing and labor-intensive process. Therefore, we have developed a new platform to probe the non-specific pharmacological potential of compounds present in common dietary supplements via shotgun derivatization with isotopically labeled propanoic acid, a live cell affinity assay, which was used to selectively recognize the population of compounds which bind tightly to HeLa cells in culture, and a computational LC-MS data analysis of isotopically labeled compounds from cell lysate. The data analysis showed that hundreds of compounds were successfully derivatized in each extract, and dozens of those compounds showed high affinity for HeLa cells. In total, over a thousand isotopically labeled compounds were screened for cell affinity across three separate experiments, resulting in the identification of several known bioactive compounds with specific protein targets and six previously unreported structures. The new natural products include three tulsinol compounds which were isolated from Ocimum tenuiflorum and three valeraninium alkaloids from Valeriana officinalis. The valeraninium alkaloids constitute a distinct new family of alkaloids from valerian, which may have previously undescribed bioactivity. These results collectively demonstrate the tag and snag workflow's viability as a drug discovery method.

Why can insects not biosynthesize cholesterol?

Two aspects of insect lipid biochemistry differ from the mammalian background. In one aspect, nearly a hundred years ago scientists demonstrated that the polyunsaturated fatty acid (PUFAs), linoleic acid (LA; 18:2n-6) is an essential nutrient in the diets of all mammals that have been studied in that regard. An unknown number of insect species are able to biosynthesize LA de novo. Some species take the biosynthesized LA into fatty acid elongation/desaturation pathways to produce other PUFAs, 18:3n-6, 20:3n-6 and 20:4n-6. A couple of species use the de novo produced LA to biosynthesize prostaglandins and other eicosanoids, short-lived signal moieties that mediate important physiological actions in immunity and reproduction. Insects differ from mammals, also, in their lack of genes that encode enzymes acting in biosynthesis of cholesterol. Insects require dietary cholesterol to meet their cellular, physiological, developmental, and reproductive needs. Looking at a broader view of invertebrate biochemistry, most protostomes lost all or most genes involved in cholesterol biosynthesis. The massive gene loss occurred during the Ediacaran Period, which lasted 96 million years, from the end of the Cryogenian Period (635 million years ago; MYA) to the beginning of the Cambrian Period (538.6 MYA). The key point here is that the inability to biosynthesize cholesterol is not limited to insects; it occured in most protostomes. We address the protostome need and benefits of acquiring exogenous sterols.

Monascus spp. and citrinin: Identification, selection of Monascus spp. isolates, occurrence, detection and reduction of citrinin during the fermentation of red fermented rice

Red fermented rice (RFR) is rice fermented using Monascus spp. This product contains monacolin K, providing health benefits including mitigation of diarrhoea and improving blood circulation. RFR can produce pigments that can act as natural colour and flavouring agents. However, Monascus spp. (a fungal starter to ferment RFR) can also produce the mycotoxin, citrinin (CIT) which is believed to have adverse effects on human health. CIT in RFR has been reported worldwide by using different methods of detection. This review focuses on the production of RFR by solid-state fermentation (SSF) and submerged fermentation (SmF), the occurrence of CIT in RFR, CIT quantification, the factors affecting the growth of Monascus spp., pigments and CIT production in RFR, and possible methods to reduce CIT in RFR. This review will help the food industries, researchers, and consumers understand the risk of consuming RFR, and the possibility of controlling CIT in RFR.

Endophytic fungi of Brunfelsia uniflora: isolation, cryopreservation, and determination of enzymatic and antioxidant activity

Brunfelsia uniflora (Pohl.) D. Don (Solanaceae), commonly known as manacá-de-cheiro, is widely distributed in Brazil and used by local indigenous peoples as an antirheumatic, antisyphilitic, depurative, emetic, vermifuge, and purgative agent. Several studies have examined the biological activities and phytochemical profile of Brunfelsia; however, few have focused on the diversity of endophytic microorganisms that colonize members of the genus. This study aimed to isolate and cryopreserve endophytic fungi from B. uniflora and determine their cellulase, laccase, and antioxidant activities. Endophytic fungi were isolated from B. uniflora stems, cultured on wheat grains, immersed in a 150 g L^-1 aqueous sucrose solution, and cryopreserved at - 80 °C for 1 and 6 months. Cellulase activity was determined by a qualitative test using carboxymethylcellulose medium and laccase activity by a quantitative test based on the oxidation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate). Prior to antioxidant activity assays, fungi were grown in malt extract broth for production of mycelial biomass. A methanolic extract was prepared for evaluation of DPPH· scavenging activity, FRAP activity, and total phenolic content. A total of 46 endophytic fungal isolates were obtained from B. uniflora stems and classified into 24 groups according to morphological similarities. B. uniflora was shown to harbor different genera of ascomycete fungi as endophytic organisms. Mycelial viability was observed after 1 and 6 months of cryopreservation at - 80 °C. Fungi exhibited cellulase and laccase activities. Isolate CE23 had the highest laccase activity after 7 days of cultivation. Twelve isolates were found to have low total phenolic contents and DPPH· and FRAP activities.

Morphological, physiological, biochemical and molecular characterization of statin-producing Penicillium microfungi isolated from little-explored tropical ecosystems

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Natural statins produced by microfungi are extremely successful drugs.

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Fungal producers of statins were isolated from soils of unique tropical habitats.

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Three novel statin-producing Penicillium strains were characterized and identified.

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Pravastatin was produced by the identified fungal cultures directly.

As hypercholesterolemia is a primary risk factor for coronary artery disease and stroke, there is now an increasing demand for cholesterol-lowering drugs. Statins are a group of extremely successful drugs that lower the cholesterol level in the blood. Natural statins are produced by fermentation using different species of microorganisms. The overall aim of the present study was to identify statin-producing microfungi, which were isolated from different types of little-explored mangrove and oil palm plantation soils. Isolated fungal cultures were characterized on the basis of morphological, physiological, biochemical, and molecular features. Morphological variability was detected amongst the fungal isolates in regard to colony morphology, conidiophores structures, and conidia coloration. Based on their physiological properties and enzyme assays, rapid differentiation of statin-producing isolates was achieved. Further molecular characterization allowed reliable identification of the selected Penicillium microfungi up to the species level. The identified Penicillium cintrinum ESF2M, Penicillium brefeldianum ESF21P, and Penicillium janthinellum ESF26P strains have a scientific interest as novel wild-type producers of natural statins.

Biological Activity and Antibiofilm Molecular Profile of Citrus aurantium Essential Oil and Its Application in a Food Model

The main aim of the study was to investigate the chemical composition, antioxidant, antimicrobial, and antibiofilm activity of Citrus aurantium essential oil (CAEO). The biofilm profile of Stenotrophonomonas maltophilia and Bacillus subtilis were assessed using the mass spectrometry MALDI-TOF MS Biotyper and the antibiofilm activity of Citrus aurantium (CAEO) was studied on wood and glass surfaces. A semi-quantitative composition using a modified version was applied for the CAEO characterization. The antioxidant activity of CAEO was determined using the DPPH method. The antimicrobial activity was analyzed by disc diffusion for two biofilm producing bacteria, while the vapor phase was used for three penicillia. The antibiofilm activity was observed with the agar microdilution method. The molecular differences of biofilm formation on different days were analyzed, and the genetic similarity was studied with dendrograms constructed from MSP spectra to illustrate the grouping profiles of S. maltophilia and B. subtilis. A differentiated branch was obtained for early growth variants of S. maltophilia for planktonic cells and all experimental groups. The time span can be reported for the grouping pattern of B. subtilis preferentially when comparing to the media matrix, but without clear differences among variants. Furthermore, the minimum inhibitory doses of the CAEO were investigated against microscopic fungi. The results showed that CAEO was most active against Penicillium crustosum, in the vapor phase, on bread and carrot in situ.

State of the Art Comprehensive Review of Individual Statins, Their Differences, Pharmacology, and Clinical Implications

Statins are currently the primary treatment for hyperlipidemia, particularly for the treatment of high levels of low-density lipoprotein cholesterol (LDL-C), as many studies have proven benefit in a variety of populations. The benefits of statin treatment for high cholesterol have been proven in many trials. Forefront among different adverse events is statin-induced myopathy, which still eludes complete understanding, and may range anywhere from muscle soreness or fatigue to potentially extremely rare occurrence of rhabdomyolysis.As most adverse events are rare and not life-threatening, in high-risk patients, a high-dose statin should be started initially as data suggests that clinicians rarely up titrate statin therapy after initial prescription leading to under-treatment of many patients requiring high-dose statin therapy. As we will discuss in this paper, musculoskeletal side effects are the main concern and reason for discontinuing statin therapy. The occurrence and true association of other adverse events in patients on statin such as new onset of diabetes, hepatic toxicity, or cognitive impairment are rare, controversial, and not proven. In placebo-controlled studies, abnormal liver function occurs to a similar degree in statin- and placebo-treated patients. This led to FDA removal of the requirement to monitor liver function tests in patients on statin therapy.The combination of statins with other compounds such as ezetimibe or PCSK9 inhibitors has shown some additional benefits in the treatment of hypercholesterolemia. The goal of this manuscript is to conduct a comprehensive review about most commonly used statins and compare data on their history, structures, benefits, adverse effects, and clinical outcomes.

Sex and the Imperfect Fungi

Approximately 20% of species in the fungal kingdom are only known to reproduce by asexual means despite the many supposed advantages of sexual reproduction. However, in recent years, sexual cycles have been induced in a series of emblematic "asexual" species. We describe how these discoveries were made, building on observations of evidence for sexual potential or "cryptic sexuality" from population genetic analyses; the presence, distribution, and functionality of mating-type genes; genome analyses revealing the presence of genes linked to sexuality; the functionality of sex-related genes; and formation of sex-related developmental structures. We then describe specific studies that led to the discovery of mating and sex in certain Candida, Aspergillus, Penicillium, and Trichoderma species and discuss the implications of sex including the beneficial exploitation of the sexual cycle. We next consider whether there might be any truly asexual fungal species. We suggest that, although rare, imperfect fungi may genuinely be present in nature and that certain human activities, combined with the genetic flexibility that is a hallmark of the fungal kingdom, might favor the evolution of asexuality under certain conditions. Finally, we argue that fungal species should not be thought of as simply asexual or sexual, but rather as being composed of isolates on a continuum of sexual fertility.

Draft Genome Sequence of the Fungus Penicillium solitum NJ1

Penicillium solitum is one of the most prevalent species causing postharvest decay of pomaceous fruits during storage. Here, we report the draft genome of P. solitum strain NJ1, received as a transfer of a strain originally identified as P. griseofulvum by classical means.

Bioactive Compounds Produced by Strains of Penicillium and Talaromyces of Marine Origin

In recent years, the search for novel natural compounds with bioactive properties has received a remarkable boost in view of their possible pharmaceutical exploitation. In this respect the sea is entitled to hold a prominent place, considering the potential of the manifold animals and plants interacting in this ecological context, which becomes even greater when their associated microbes are considered for bioprospecting. This is the case particularly of fungi, which have only recently started to be considered for their fundamental contribution to the biosynthetic potential of other more valued marine organisms. Also in this regard, strains of species which were previously considered typical terrestrial fungi, such as Penicillium and Talaromyces, disclose foreground relevance. This paper offers an overview of data published over the past 25 years concerning the production and biological activities of secondary metabolites of marine strains belonging to these genera, and their relevance as prospective drugs.

Epigenetics as an emerging tool for improvement of fungal strains used in biotechnology

Filamentous fungi are today a major source of industrial biotechnology for the production of primary and secondary metabolites, as well as enzymes and recombinant proteins. All of them have undergone extensive improvement strain programs, initially by classical mutagenesis and later on by genetic manipulation. Thereby, strategies to overcome rate-limiting or yield-reducing reactions included manipulating the expression of individual genes, their regulatory genes, and also their function. Yet, research of the last decade clearly showed that cells can also undergo heritable changes in gene expression that do not involve changes in the underlying DNA sequences (=epigenetics). This involves three levels of regulation: (i) DNA methylation, (ii) chromatin remodeling by histone modification, and (iii) RNA interference. The demonstration of the occurrence of these processes in fungal model organisms such as Aspergillus nidulans and Neurospora crassa has stimulated its recent investigation as a tool for strain improvement in industrially used fungi. This review describes the progress that has thereby been obtained.

Improvement of hepatic bioavailability as a new step for the future of statin

Statins (HMG-CoA reductase inhibitors) are a group of highly efficient pharmacological agents used for reducing blood cholesterol level and prevention/treatment of cardiovascular disease. Adverse reactions during statin treatment affect quite significant numbers of patients (reportedly from 5% to 20%), with more side effects occurring at higher doses. Reduced statin dosing can be achieved by improved bioavailability of statins, which is fairly low due to poor aqueous solubility, low permeability and high molecular weight of some members of the statin family. Moreover, since hepatic cholesterologenesis is a main target of statin action and extrahepatic inhibition of HMG-CoA reductase has no effect on plasma lipids, hepatic bioavailability, in our opinion, becomes a new important modality of statins maximizing their potential effect on the plasma lipid profile and diminishing their extrahepatic toxicity. Therefore efficient delivery systems of statins into hepatocytes need to be developed and introduced. Uses of nano-emulsifying statin delivery systems which may include vectors of intrahepatic transport, in particular lycopene, are discussed. As a proof of concept, some preliminary results revealing the effect of a lycopene-containing nanoformulation of simvastatin (designated as Lyco-Simvastatin) on LDL in mildly hypercholesterolemic patients are shown.

Inflammatory stress reduces the effectiveness of statins in the kidney by disrupting HMGCoA reductase feedback regulation

BACKGROUND

Patients with chronic kidney disease (CKD) are unlikely to gain the same benefit from conventional doses of statins as do patients with cardiovascular disease alone. This study investigated whether inflammation accompanying CKD causes statin resistance.

METHODS

Inflammatory stress was induced by adding cytokines and lipopolysaccharide (LPS) to human mesangial cells (HMCs) in vitro, and in vivo by subcutaneous casein injection in apolipoprotein E, scavenger receptors class A and CD36 triple knockout mice.

RESULTS

Inflammatory stress exacerbated cholesterol accumulation and was accompanied in vitro and in vivo by increased HMGCoA reductase (HMGCoA-R) mRNA and protein expression mediated via activation of the sterol regulatory element-binding protein cleavage-activating protein (SCAP)/sterol regulatory element-binding protein 2 pathway. Atorvastatin reduced HMGCoA-R enzymatic activity and intracellular cholesterol synthesis in vitro; however, inflammatory stress weakened these suppressive effects. Atorvastatin at concentrations of 15 µM inhibited HMGCoA-R activity by 50% (IC50) in HMCs, but the same concentration in the presence of interleukin (IL)-1β resulted in only 30% inhibition of HMGCoA-R activity in HMCs. Knocking down SCAP prevented statin resistance induced by IL-1β, and overexpression of SCAP-induced statin resistance even without inflammatory stress. In vivo, the amount of atorvastatin required to lower serum cholesterol and decrease kidney lipid accumulation rose from 2 to 10 mg/kg/day in the presence of inflammatory stress.

CONCLUSIONS

Inflammatory stress can disrupt HMGCoA-R-mediated cholesterol synthesis resulting in intracellular lipid accumulation and statin resistance.

Inflammatory stress induces statin resistance by disrupting 3-hydroxy-3-methylglutaryl-CoA reductase feedback regulation

OBJECTIVE

The risk of cardiovascular disease is increased by up to 33 to 50× in chronic inflammatory states and convention doses of statins may not provide the same cardiovascular protection as in noninflamed patients. This study investigated whether the increase in 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCoA-R)-mediated cholesterol synthesis observed under inflammatory stress was resistant to the action of statins and if so, whether this was because of interference with the sterol regulatory element binding protein cleavage-activating protein pathway.

APPROACH AND RESULTS

Inflammatory stress was induced by adding cytokines (interleukin-1β, tumor necrosis factor-α, and interleukin-6) and lipopolysaccharides to vascular smooth muscle cells in vitro and by subcutaneous casein injection in apolipoprotein E/scavenger receptors class A/CD36 triple knockout mice in vivo. Inflammatory stress exacerbated cholesterol ester accumulation and was accompanied in vitro and in vivo by increased HMGCoA-R mRNA and protein expression mediated via activation of the sterol regulatory element binding protein cleavage-activating protein/sterol regulatory element binding protein-2 pathway. Atorvastatin reduced HMGCoA-R enzymatic activity and intracellular cholesterol synthesis in vitro. However, inflammatory stress weakened these suppressive effects. Atorvastatin at concentrations of 16 μmol/L inhibited HMGCoA-R activity by 50% in vascular smooth muscle cells, but the same concentration resulted in only 30% of HMGCoA-R activity in vascular smooth muscle cells in the presence of interleukin-1β. Knocking down sterol regulatory element binding protein cleavage-activating protein prevented statin resistance induced by interleukin-1β, and overexpression of sterol regulatory element binding protein cleavage-activating protein induced statin resistance even without inflammatory stress. In vivo, the amount of atorvastatin required to lower serum cholesterol and decrease aortic lipid accumulation rose from 2 to 10 mg/kg per day in the presence of inflammatory stress.

CONCLUSIONS

Increased cholesterol synthesis mediated by HMGCoA-R under inflammatory stress may be one of the mechanisms for intracellular lipid accumulation and statin resistance.

Complete mitochondrial genome of compactin-producing fungus Penicillium solitum and comparative analysis of Trichocomaceae mitochondrial genomes

We determined the complete mitochondrial genome sequence of the compactin-producing fungus Penicillium solitum strain 20-01. The 28 601-base pair circular-mapping DNA molecule encodes a characteristic set of mitochondrial proteins and RNA genes and is intron-free. All 46 protein- and RNA-encoding genes are located on one strand and apparently transcribed in one direction. Comparative analysis of this mtDNA and previously sequenced but unannotated mitochondrial genomes of several medically and industrially important species of the Aspergillus/Penicillium group revealed their extensive similarity in terms of size, gene content and sequence, which is also reflected in the almost perfect conservation of mitochondrial gene order in Penicillium and Aspergillus. Phylogenetic analysis based on concatenated mitochondrial protein sequences confirmed the monophyletic origin of Eurotiomycetes.

Deslongchamps annulations with benzoquinone monoketals

The so-called Deslongchamps annulation of deprotonated γ,δ-unsaturated β-ketoesters 15 to 2-(alkoxycarbonyl)cyclohex-2-en-1-ones or similarly activated cyclohex-2-en-1-ones offers a versatile access to various kinds of decalindiones. The scope of Deslongchamps annulations was extended by establishing acceptor-substituted benzoquinone monoketals such as 13 as viable substrates. They gave octalindiones such as 35 with diastereoselectivities ≥ 95:5.

Assessment of monacolin in the fermented products using Monascus purpureus FTC5391

Monacolins, as natural statins, form a class of fungal secondary metabolites and act as the specific inhibitors of HMG-CoA reductase. The interest in using the fermented products as the natural source of monacolins, instead of statin drugs, is increasing enormously with its increasing demand. In this study, the fermented products were produced by Monascus purpureus FTC5391 using submerged and solid state fermentations. Two commercial Monascus-fermented products were also evaluated for comparison. Improved methods of monacolins extraction and identification were developed for the assessment of monacolins in the fermented products. Methanol and ethanol were found to be the most favorable solvents for monacolins extraction due to their ability to extract higher amount of monacolin K and higher numbers of monacolin derivatives. Problem related to false-positive results during monacolins identification was solved by adding monacolin lactonization step in the assessment method. Using this improved method, monacolin derivatives were not detected in all Monascus-fermented products tested in this study, suggesting that their hypocholesterolemic effects may be due to other compounds other than monacolins.

Screening of nutrient parameters for mevastatin production by Penicillium citrinum MTCC 1256 under submerged fermentation using the Plackett-Burman design

OBJECTIVE

Mevastain, an HMG-CoA reductase inhibitor produced by Penicillium citrinum. The Placket-Burman experimental design was used to identify the important nutrients influencing the production of mevastatin by Penicillium citrinum MTCC 1256 under submerged fermentation.

MATERIALS AND METHODS

Nine nutritional parameters, such as, glucose, glycerol, arrowroot, oats, urea, peptone, yeast extract, MgSO(4).7H(2)O, and CaCl(2).2H(2)O were screened by Placket-Burman experimental design in 12 experimental run.

RESULTS

Nine nutritional parameters, glucose, glycerol, arrowroot, oats, urea, peptone, yeast extract, MgSO(4).7H(2)O, and CaCl(2).2H(2)O contributed with 0.8114%, 24.0390%, 2.2786%, 0.1491%, 0.5608%, 47.5029%, 6.8092 %, 4.0980%, 10.5823% respectively towards mevastatin production by Penicillium citrinum under submerged fermentation.

CONCLUSION

Among the nine nutrient components glycerol, peptone, yeast extract, MgSO(4).7H(2)0, and CaCl(2).2H(2)O contributed to a large extent, urea had little impact, while glucose, oats, and arrowroot contributed moderately on production of mevastatin.

Caveolin-1 interacts with alpha-synuclein and mediates toxic actions of cellular alpha-synuclein overexpression

Caveolin-1 (Cav-1) is a transmembrane protein which clusters proteins and lipids at the cell membrane into a subclass of lipid rafts named caveolae. To increase our understanding about putative functions of Cav-1 in neuronal cells, we used mouse brain extracts and a novel technology coupling surface plasmon resonance to mass spectrometry to find binding partners to Cav-1. An interaction between Cav-1 and alpha-synclein was found and confirmed in reciprocal pulldown experiments. Genetic overexpression of alpha-synclein in mouse neuroblastoma Neuro2A cells (N2A) expectedly decreased cell survival, but also significantly increased the levels of Cav-1. Furthermore, si-RNA-mediated knockdown of Cav-1 counteracted cell death induced by overexpression of alpha-synuclein. We also used an inhibitor of proteasome (MG132) to induce cell death in a Parkinson's disease context. Cav-1 knockdown had no effect on cell death induced by MG132. Conversely, treating the cells with mevastatin, an inhibitor of cholesterol synthesis, inhibits cell death induced by MG132, but not by alpha synuclein overexpression. It can be concluded that Cav-1 may play a functional role in neuronal cells by virtue of its physical interaction with alpha-synuclein and regulate alpha synuclein-mediated actions on cell death, processes known to be involved in synucleinopathies including Parkinson's disease.

Biosynthesis of lovastatin and related metabolites formed by fungal iterative PKS enzymes

The fungal polyketide lovastatin is a cholesterol lowering agent that is an immediate precursor to a multi-billion dollar drug, simvastatin (Zocor). Lovastatin is produced by an iterative type I polyketide synthase known as LovB and a partner enoyl reductase (LovC). There is evidence that a Diels-Alderase enzyme activity is utilized in its biosynthesis. This review examines the biosynthesis of lovastatin, as well as of compactin, equisetin, cytochalasins, and solanapyrones, which are other structurally related polyketides that appear to utilize a Diels-Alderase.

Surveys of non-ribosomal peptide and polyketide assembly lines in fungi and prospects for their analysis in vitro and in vivo

With many bioactive non-ribosomal peptides and polyketides produced in fungi, studies of their biosyntheses are an active area of research. Practical limitations of working with mega-dalton synthetases including cell lysis and protein extraction to recombinant gene and pathway expression has slowed understanding of many secondary metabolic processes relative to bacterial counterparts. Recent advances in accessing fungal biosynthetic machinery are beginning to change this. Here we describe the successes of some studies of thiotemplate biosynthesis in fungal systems, along with very recent advances in chemical tagging and mass spectrometric strategies to selectively study biosynthetic conveyer belts in isolation, and within a few years, in endogenous fungal proteomes.

Biotechnological production and applications of statins

Statins are a group of extremely successful drugs that lower cholesterol levels in blood; decreasing the risk of heath attack or stroke. In recent years, statins have also been reported to have other biological activities and numerous potential therapeutic uses. Natural statins are lovastatin and compactin, while pravastatin is derived from the latter by biotransformation. Simvastatin, the second leading statin in the market, is a lovastatin semisynthetic derivative. Lovastatin is mainly produced by Aspergillus terreus strains, and compactin by Penicillium citrinum. Lovastatin and compactin are produced industrially by liquid submerged fermentation, but can also be produced by the emerging technology of solid-state fermentation, that displays some advantages. Advances in the biochemistry and genetics of lovastatin have allowed the development of new methods for the production of simvastatin. This lovastatin derivative can be efficiently synthesized from monacolin J (lovastatin without the side chain) by a process that uses the Aspergillus terreus enzyme acyltransferase LovD. In a different approach, A. terreus was engineered, using combinational biosynthesis on gene lovF, so that the resulting hybrid polyketide synthase is able to in vivo synthesize 2,2-dimethylbutyrate (the side chain of simvastatin). The resulting transformant strains can produce simvastatin (instead of lovastatin) by direct fermentation.

Protein profiling of the dimorphic, pathogenic fungus, Penicillium marneffei

Background

Penicillium marneffei is a pathogenic fungus that afflicts immunocompromised individuals having lived or traveled in Southeast Asia. This species is unique in that it is the only dimorphic member of the genus. Dimorphism results from a process, termed phase transition, which is regulated by temperature of incubation. At room temperature, the fungus grows filamentously (mould phase), but at body temperature (37°C), a uninucleate yeast form develops that reproduces by fission. Formation of the yeast phase appears to be a requisite for pathogenicity. To date, no genes have been identified in P. marneffei that strictly induce mould-to-yeast phase conversion. In an effort to help identify potential gene products associated with morphogenesis, protein profiles were generated from the yeast and mould phases of P. marneffei.

Results

Whole cell proteins from the early stages of mould and yeast development in P. marneffei were resolved by two-dimensional gel electrophoresis. Selected proteins were recovered and sequenced by capillary-liquid chromatography-nanospray tandem mass spectrometry. Putative identifications were derived by searching available databases for homologous fungal sequences. Proteins found common to both mould and yeast phases included the signal transduction proteins cyclophilin and a RACK1-like ortholog, as well as those related to general metabolism, energy production, and protection from oxygen radicals. Many of the mould-specific proteins identified possessed similar functions. By comparison, proteins exhibiting increased expression during development of the parasitic yeast phase comprised those involved in heat-shock responses, general metabolism, and cell-wall biosynthesis, as well as a small GTPase that regulates nuclear membrane transport and mitotic processes in fungi. The cognate gene encoding the latter protein, designated RanA, was subsequently cloned and characterized. The P. marneffei RanA protein sequence, which contained the signature motif of Ran-GTPases, exhibited 90% homology to homologous Aspergillus proteins.

Conclusion

This study clearly demonstrates the utility of proteomic approaches to studying dimorphism in P. marneffei. Moreover, this strategy complements and extends current genetic methodologies directed towards understanding the molecular mechanisms of phase transition. Finally, the documented increased levels of RanA expression suggest that cellular development in this fungus involves additional signaling mechanisms than have been previously described in P. marneffei.

Food, not nutrients, is the fundamental unit in nutrition

The identification of nutrients and the study of their bioactivity were significant developments in the evolution of contemporary nutrition science. This review argues for shifting the focus towards food in order to better understand the nutrition-health interface. It begins by introducing the concept of food synergy (a perspective that more information can be obtained by looking at foods than at single food components) to denote the action of the food matrix (the composite of naturally occurring food components) on human biological systems. A proposal is then made for the means by which food-focused research might build the knowledge base for etiologic discovery and appropriate dietary advice. The diet-heart disease dilemma is put forward as an example of where a nutrient-based approach has limitations, and a summary of studies targeting food composition strengthens the case for a food-based approach. Finally, the argument is made that evidence from interventions points back to the central position of food in the relationship between nutrition and health, a position that begs for more whole food-based research.

Structural insights into drug processing by human carboxylesterase 1: tamoxifen, mevastatin, and inhibition by benzil

Human carboxylesterase 1 (hCE1) exhibits broad substrate specificity and is involved in xenobiotic processing and endobiotic metabolism. We present and analyze crystal structures of hCE1 in complexes with the cholesterol-lowering drug mevastatin, the breast cancer drug tamoxifen, the fatty acyl ethyl ester (FAEE) analogue ethyl acetate, and the novel hCE1 inhibitor benzil. We find that mevastatin does not appear to be a substrate for hCE1, and instead acts as a partially non-competitive inhibitor of the enzyme. Similarly, we show that tamoxifen is a low micromolar, partially non-competitive inhibitor of hCE1. Further, we describe the structural basis for the inhibition of hCE1 by the nanomolar-affinity dione benzil, which acts by forming both covalent and non-covalent complexes with the enzyme. Our results provide detailed insights into the catalytic and non-catalytic processing of small molecules by hCE1, and suggest that the efficacy of clinical drugs may be modulated by targeted hCE1 inhibitors.