From Genes to Molecules, Secondary Metabolism in Botrytis cinerea: New Insights into Anamorphic and Teleomorphic Stages.

The ascomycete Botrytis cinerea Pers. Fr., classified within the family Sclerotiniaceae, is the agent that causes grey mould disease which infects at least 1400 plant species, including crops of economic importance such as grapes and strawberries. The life cycle of B. cinerea consists of two phases: asexual (anamorph, Botrytis cinerea Pers. Fr.) and sexual (teleomorph, Botryotinia fuckeliana (de Bary) Wetzel). During the XVI International Symposium dedicated to the Botrytis fungus, which was held in Bari in June 2013, the scientific community unanimously decided to assign the most widely used name of the asexual form, Botrytis, to this genus of fungi. However, in the literature, we continue to find articles referring to both morphic stages. In this review, we take stock of the genes and metabolites reported for both morphic forms of B. cinerea between January 2015 and October 2022.

[Prevalence and genotypes of cervical and vaginal HPV in female sex workers attending a Sexual Control Centre, North Area of Santiago, Chile]. / Prevalencia y genotipicación de virus papiloma humano vaginal y cervical en trabajadoras sexuales de un centro de salud sexual en la zona Norte de Santiago, Chile.

BACKGROUND: In Chile, cervical cancer is the second leading cause of death from malignancy in women. The main causal agent of cervical cancer is the human papillomavirus (HPV). Compared with the general population, sex workers (SW) are at increased risk of acquiring HPV. AIM: To analyze the prevalence and genotypes of cervical and vaginal HPV in female SW attending a Sexual Control Centre. METHODS: A cross-sectional study was carried out on 97 women (19-70 years old). Two samples were taken per patient, one from exocervix and the other from vaginal walls. HPV DNA. was identified by polymerase chain reaction (PCR) and genotyping using specific probes for 32 types of HPV. RESULTS: The overall frequency of HPV was 45%, 41.2% in cervical carrier and 36.1% in vaginal carrier, 32% were co-infected, 63% of HPV were high-risk genotypes. The most frequent high-risk HPV was HPV 66 (12%), HPV 58 (9.3%), followed by HPV 16, HPV 59 and HPV 82 with the same frequency (8% each one). Thirty two (43%) of females were infected with multiple genotypes. CONCLUSION: HPV is frequent infection among SW. This is the first study in Chile on the prevalence and genotypes of HPV in sex workers.

Prevalencia y genotipicación de virus papiloma humano vaginal y cervical en trabajadoras sexuales de un centro de salud sexual en la zona Norte de Santiago, Chile / Prevalence and genotypes of cervical and vaginal HPV in female sex workers attending a Sexual Control Centre, North Area of Santiago, Chile

INTRODUCCIÓN: En Chile, el cáncer de cuello uterino (CCU) es la segunda causa de muerte por neoplasias malignas en la mujer. El principal agente causal es el virus papiloma humano (VPH). Comparando con la población general, los o las trabajadoras(es) sexuales (TS) tienen alto riesgo de adquirir VPH. OBJETIVO: Analizar la prevalencia y genotipos del VPH cervical y vaginal en TS que se atienden en un Centro de Salud Sexual de Santiago, Chile. Pacientes y MÉTODO: Se realizó un estudio transversal en 97 mujeres TS, de 19 a 70 años de edad. Se obtuvieron dos muestras por paciente, una de exocérvix y otra de paredes vaginales. El ADN de VPH fue identificado por reacción de polimerasa en cadena (RPC) y su genotipo fue investigado para 32 tipos de VPH. RESULTADOS: La prevalencia de VPH global fue de 45%, observándose portación cervical en 41,2% y vaginal en 36,1%, con una coinfección de 32%. El 63% de las muestras tenía genotipos de alto riesgo. Los VPH de alto riesgo más frecuentes fueron el VPH 66 (12%), VPH 58 (9,3%), seguidos por VPH 16, VPH 59 y VPH 82 con igual frecuencia (8% c/u). Treinta y dos mujeres (43%) fueron infectadas con genotipos múltiples. CONCLUSIÓN: El VPH es una infección frecuente entre las TS. Este es el primer estudio en Chile sobre prevalencia y genotipos de VPH en TS.

BACKGROUND: In Chile, cervical cancer is the second leading cause of death from malignancy in women. The main causal agent of cervical cancer is the human papillomavirus (HPV). Compared with the general population, sex workers (SW) are at increased risk of acquiring HPV. AIM: To analyze the prevalence and genotypes of cervical and vaginal HPV in female SW attending a Sexual Control Centre. METHODS: A cross-sectional study was carried out on 97 women (19-70 years old). Two samples were taken per patient, one from exocervix and the other from vaginal walls. HPV DNA. was identified by polymerase chain reaction (PCR) and genotyping using specific probes for 32 types of HPV. RESULTS: The overall frequency of HPV was 45%, 41.2% in cervical carrier and 36.1% in vaginal carrier, 32% were co-infected, 63% of HPV were high-risk genotypes. The most frequent high-risk HPV was HPV 66 (12%), HPV 58 (9.3%), followed by HPV 16, HPV 59 and HPV 82 with the same frequency (8% each one). Thirty two (43%) of females were infected with multiple genotypes. CONCLUSION: HPV is frequent infection among SW. This is the first study in Chile on the prevalence and genotypes of HPV in sex workers.

Reactive arthritis: images.

Reactive arthritis is an extremely rare spondyloarthritis that affects the peripheral joints and spine, resulting in common symptoms such as arthritis, urethritis, conjunctivitis, and mucocutaneous lesions. On rare occasions, oral lesions such as circinate erosions on the hard and soft palate, gums, tongue, and cheeks may occur. Reactive arthritis may develop during or after genitourinary or gastrointestinal bacterial infections such as Shigella, Salmonella, Yersinia, and Chlamydia. A 36-year-old man presented with circinate balanitis, urethral discharge, oligoarthralgia, conjunctivitis, lymphadenopathy, pharyngitis, and erythematous lesions on the palate. Culture examination showed presence of Neisseria gonorrhoeae and antibiotic treatment resulted in improvement of conjunctivitis and the lesions on the penis. However, severe oligoarthralgia, palatal erosions that increased in severity and size, and depilated areas on the tongue were observed. The definitive diagnosis was reactive arthritis. The prevalence of sexually transmitted infections is increasing, highlighting the need to increase awareness of associated risks such as reactive arthritis. Moreover, consideration of non-specific oral manifestations in a systemic context may aid in effective diagnosis and treatment, suggesting the need for multidisciplinary teams.

Impairment of botrydial production in Botrytis cinerea allows the isolation of undescribed polyketides and reveals new insights into the botcinins biosynthetic pathway.

Botrytis cinerea is a necrotrophic fungal pathogen that affects a total of 586 genera representing approximately 1400 plant species. This pathogen produces two families of phytotoxins involved in its infection process i.e. botrydial and its relatives, and botcinic and botcineric acids and their relatives, botcinins. The botrydial biosynthetic cluster consists of seven genes, where the gene BcBOT4 encodes a cytochrome P450 monooxygenase that was shown to catalyse regio- and stereospecific hydroxylation at position C-4 of the presilphiperfolan-8-ß-ol skeleton. The null mutant bcbot4Δ halted the production of botrydial and its derivatives, and instead accumulated tricyclic presilphiperfolane alcohol and overproduced a significant number of polyketides. A detailed study of the bcbot4Δ mutant led us to the isolation and characterization of five undescribed polyketides, three derived from botcinic and botcineric acids (botcinins H, I, J), one derived from the initial pentaketide (botcinin K), and one cinbotolide derivative (cinbotolide D). Botcinins are tetra-methylated tetraketides biosynthesized by the sequential assembly of a pentaketide (C10) based on an acetate primer unit which is lost through a retro-Claisen type C-C bond cleavage. The structural characterization of botcinin K showed a basic chemical structure corresponding to a botcinin (C14) derivative obtained directly from the original per-methylated pentaketide leading to the biosynthesis of botrylactone and other botcinins, confirming the previously proposed biosynthetic route.

Biocatalytic Preparation of Chloroindanol Derivatives. Antifungal Activity and Detoxification by the Phytopathogenic Fungus Botrytis cinerea.

Indanols are a family of chemical compounds that have been widely studied due to their broad range of biological activity. They are also important intermediates used as synthetic precursors to other products with important applications in pharmacology. Enantiomerically pure chloroindanol derivatives exhibiting antifungal activity against the phytopathogenic fungus Botrytis cinerea were prepared using biocatalytic methods. As a result of the biotransformation of racemic 6-chloroindanol (1) and 5-chloroindanol (2) by the fungus B. cinerea, the compounds anti-(+)-6-chloroindan-1,2-diol (anti-(+)-7), anti-(+)-5-chloroindan-1,3-diol (anti-(+)-8), syn-(+)-5-chloroindan-1,3-diol (syn-(+)-8), syn-(-)-5-chloroindan-1,3-diol (syn-(-)-8), and anti-(+)-5-chloroindan-1,2-diol (anti-(+)-9) were isolated for the first time. These products were characterized by spectroscopic techniques and their enantiomeric excesses studied by chromatographic techniques. The results obtained in the biotransformation seem to suggest that the fungus B. cinerea uses oxidation reactions as a detoxification mechanism.

Botrydial confers Botrytis cinerea the ability to antagonize soil and phyllospheric bacteria.

The role of the sesquiterpene botrydial in the interaction of the phytopathogenic fungus Botrytis cinerea and plant-associated bacteria was analyzed. From a collection of soil and phyllospheric bacteria, nine strains sensitive to growth-inhibition by B. cinerea were identified. B. cinerea mutants unable to produce botrydial caused no bacterial inhibition, thus demonstrating the inhibitory role of botrydial. A taxonomic analysis showed that these bacteria corresponded to different Bacillus species (six strains), Pseudomonas yamanorum (two strains) and Erwinia aphidicola (one strain). Inoculation of WT and botrydial non-producing mutants of B. cinerea along with Bacillusamyloliquefaciens strain MEP218 in soil demonstrated that both microorganisms exert reciprocal inhibitory effects; the inhibition caused by B. cinerea being dependent on botrydial production. Moreover, botrydial production was modulated by the presence of B. amyloliquefaciens MEP218 in confrontation assays in vitro. Purified botrydial in turn, inhibited growth of Bacillus strains in vitro and cyclic lipopeptide (surfactin) production by B. amyloliquefaciens MEP218. As a whole, results demonstrate that botrydial confers B. cinerea the ability to inhibit potential biocontrol bacteria of the genus Bacillus. We propose that resistance to botrydial could be used as an additional criterion for the selection of biocontrol agents of plant diseases caused by B. cinerea.

Biodegradation and toxicity reduction of nonylphenol, 4-tert-octylphenol and 2,4-dichlorophenol by the ascomycetous fungus Thielavia sp HJ22: Identification of fungal metabolites and proposal of a putative pathway.

Research on the biodegradation of emerging pollutants is gained great focus regarding their detrimental effects on the environment and humans. The objective of the present study was to evaluate the ability of the ascomycetes Thielavia sp HJ22 to remove the phenolic xenobiotics nonylphenol (NP), 4-tert-octylphenol (4-tert-OP) and 2,4-dichlorophenol (2,4-DCP). The strain showed efficient degradation of NP and 4-tert-OP with 95% and 100% removal within 8 h of incubation, respectively. A removal rate of 80% was observed with 2,4-DCP within the same time. Under experimental conditions, the degradation of the tested pollutants concomitantly increased with the laccase production and cytochrome P450 monooxygenases inhibition. This study showed the involvement of laccase in pollutants removal together with biosorption mechanisms. Additionally, results demonstrated the participation of cytochrome P450 monooxygenase in the elimination of 2,4-DCP. Liquid chromatography-mass spectrometry analysis revealed several intermediates, mainly hydroxylated and oxidized compounds with less harmful effects compared to the parent compounds. A decrease in the toxicity of the identified metabolites was observed using Aliivibrio fischeri as bioindicator. The metabolic pathways of degradation were proposed based on the identified metabolites. The results point out the potential of Thielavia strains in the degradation and detoxification of phenolic xenobiotics.

Natural Compounds That Modulate the Development of the Fungus Botrytis cinerea and Protect Solanum lycopersicum.

Botrytis cinerea is the causal agent of gray mold disease and is responsible for the loss of millions of dollars in crops in worldwide. Currently, this pathogen exhibits increasing resistance to conventional fungicides; therefore, better control methods and novel compounds with a more specific mechanism of action but without biocidal effects, are required. In this work, several natural compounds to control B. cinerea were analyzed in vitro. Detected effects were dependent on the stage of fungus development, and 3-phenyl-1-propanol displayed the most potent inhibition of in vitro germination, germ tube development, and sporulation. However, it had lower protection of leaves and postharvest fruit in plant infection. Isoeugenol and 1-phenylethanol exhibited lower inhibition of in vitro germination and sporulation, but at the highest concentrations, they inhibited germ tube elongation. Although the lowest rates of foliage infection were recorded using isoeugenol and 3-phenyl-1-propanol, 1-phenylethanol significantly decreased the disease in postharvest tomato fruit, with an efficacy like Mancozeb, but at 18 times lower micromolar concentration. All compounds resulted in high cell viability after spores were removed from the treatment solution exhibited high cell viability, suggesting a non-biocidal effect. The diversity of in vitro and in-plant effects seems to indicate a different mechanism of action.

Botcinic acid biosynthesis in Botrytis cinerea relies on a subtelomeric gene cluster surrounded by relics of transposons and is regulated by the Zn2Cys6 transcription factor BcBoa13.

Botcinic acid is a phytotoxic polyketide involved in the virulence of the gray mold fungus Botrytis cinerea. Here, we aimed to investigate the specific regulation of the cluster of Bcboa genes that is responsible for its biosynthesis. Our analysis showed that this cluster is located in a subtelomeric genomic region containing alternating G + C/A + T-balanced regions, and A + T-rich regions made from transposable elements that underwent RIP (Repeat-Induced Point mutation). Genetic analyses demonstrated that BcBoa13, a putative Zn2Cys6 transcription factor, is a nuclear protein with a major positive regulatory role on the expression of other Bcboa1-to-Bcboa12 genes, and botcinic acid production. In conclusion, the structure and the regulation of the botcinic acid gene cluster show similar features with the cluster responsible for the biosynthesis of the other known phytotoxin produced by B. cinerea, i.e., the sesquiterpene botrydial. Both clusters contain a gene encoding a pathway-specific Zn2Cys6 positive regulator, and both are surrounded by relics of transposons which raise some questions about the role of these repeated elements in the evolution and regulation of the secondary metabolism gene clusters in Botrytis.

Effects of 1064-nm Nd:YAG long-pulse laser on polidocanol microfoam injected for varicose vein treatment: a controlled observational study of 404 legs, after 5-year-long treatment.

Sclerotherapy continues to be the treatment of choice for varicose veins in the legs. However, isolated treatment using microfoam or lasers requires a high number of sessions to eliminate them. In 2013, we published results about the efficacy and safety 3 years after the combined treatment with microfoam injections and subsequent application of Nd:YAG laser. The aim of this paper is to clinically evaluate the treatment of varices in a control visit after 5 years, when polidocanol microfoam is used and is immediately irradiated in the tissue with 1064-nm Nd:YAG laser beam. The outcome persistence after 5 years was studied in the legs that had received combined treatment and had been studied 3 years after treatment. Patients were contacted by phone, interviewed, and examined with echo-Doppler. Out of the 259 patients who were contacted, 221 agreed to make the appointment, although in the end, only 202 came, which meant analysing 404 legs. At 5 years, the clearance rates were very high: patients were included in class CEAP C1 showing vessels of from 0.5 to 3 mm diameter. The patients showed a high level of satisfaction. Regarding adverse effects, only 4 cases of hypopigmentation described in the previous publication persisted. Although the action mechanisms between the microfoam and the Nd:YAG laser must still be elucidated, it is notable that combining microfoam with laser exposure obtained a complete, effective treatment of legs in only 2 sessions, with high clearance rates and high level of satisfaction among patients.

Bacteriophages as an Up-and-Coming Alternative to the Use of Sulfur Dioxide in Winemaking.

Certain acetic and lactic acid bacteria are major causes of quality defects in musts and wines, giving rise to defects such as a "vinegary," "sharp, like nail polish-remover" taste or preventing alcoholic and/or malolactic fermentation. Sulfur dioxide is the major tool currently used in the control of these bacteria in wine. The aim of this work was to isolate bacteriophages from musts and wine of different grape varieties that were able to eliminate lactic and acetic acid bacteria spoilages at the laboratory scale. Musts obtained from grape-berries of Vitis vinifera cv. Chardonnay and Moscatel and a red wine made with V. vinifera cv. Tintilla de Rota were used to isolate bacteriophages. Bacteriophages were obtained from each of the musts and the wine and belonged to the order Caudovirals and the family Tectivirals. They were isolated by classical virology methods and identified by electron microscopy. The host bacteria used in the study were lactic acid bacteria of the species Lactobacillus hilgardii, Lactobacillus plantarum, and Oenococcus oeni and the acetic bacteria Acetobacter aceti. A comparative study was performed by adding phage titrations and SO2 to musts and wines, which had been previously inoculated with bacteria, to study the effectiveness of bacteriophages against bacteria. The comparative study showed that some bacteriophages were as effective as sulfur dioxide at low concentrations.

A GC-MS untargeted metabolomics approach for the classification of chemical differences in grape juices based on fungal pathogen.

Fungal bunch rot of grapes leads to production of detrimental flavour compounds, some of which are well characterised but others remain unidentified. The current study uses an untargeted metabolomics approach to classify volatile profiles of grape juices based on the presence of different fungal pathogens. Individual grape berries were inoculated with Botrytis cinerea, Penicillium expansum, Aspergillus niger or A. carbonarius. Grape bunches were inoculated and blended with healthy fruit, to provide 10% (w/w) infected juice. Juices from the above sample batches were analysed by GC/MS. PLS-DA of the normalised summed mass ions indicated sample classification according to pathogen. Compounds identified from those mass ion matrices that had high discriminative value for classification included 1,5-dimethylnaphthalene and several unidentified sesquiterpenes that were relatively higher in B. cinerea infected samples. A. niger and A. carbonarius samples were relatively higher in 2-(4-hexyl-2,5-dioxo-2,5-dihydrofuran-3-yl)acetic acid, while P. expansum samples were higher in γ-nonalactone and m-cresol.

Structural and biosynthetic studies on eremophilenols related to the phytoalexin capsidiol, produced by Botrytis cinerea.

A thorough study of the fermentation broth of three strains of Botrytis cinerea which were grown on a modified Czapek-Dox medium supplemented with 5 ppm copper sulphate, yielded five undescribed metabolites. These metabolites possessed a sesquiterpenoid (+)-4-epi-eremophil-9-ene carbon skeleton which was enantiomeric to that of the phytoalexin, capsidiol. The isolation of these metabolites when the fungus was stressed, suggests that they may be potential effectors used by B. cinerea to circumvent plant chemical defences against phytopathogenic fungi. The biosynthesis of these compounds has been studied using 2H and 13C labelled acetate.

Relevance of the deletion of the Tatri4 gene in the secondary metabolome of Trichoderma arundinaceum.

The fungus Trichoderma arundinaceum (Ta37) has a significant biocontrol application which has been related to the production of the trichothecene, harzianum A (2). Previous studies with a strain of T. arundinaceum which was blocked for the production of 2, revealed the existence of a chemical cross-regulation between the biocontrol fungus and its target organism. A study of the secondary metabolome of a single culture of a mutant of T. arundinaceum TaΔTri4 which produces trichothecene biosynthetic intermediates, has now been carried out. The production of secondary metabolites in a co-culture with the phytopathogen, Botrytis cinerea, was then analyzed. The mutant produced a larger quantity of the aspinolides B (6) and C (7) and other derivatives when compared to the wild type Ta37. Ten new metabolites were isolated: three aspinolides 12-14, the γ-lactones 15 and 16, two hemi-ketals 17 and 18 and three aspinolide degradation products, 19, 21 and 22. In the confrontation cultures involving the TaΔTri4 and the B. cinerea B05.10 strains, there was a higher production of the aspinolides B and C by the TaΔTri4 mutant while the production of the botryanes and botcinins by B. cinerea was reduced in the area of interaction between the cultures. These results shed light on the chemical cross-talk and ecological interactions between these fungi.

The sesquiterpene botrydial from Botrytis cinerea induces phosphatidic acid production in tomato cell suspensions.

MAIN CONCLUSION: The phytotoxin botrydial triggers PA production in tomato cell suspensions via PLD and PLC/DGK activation. PLC/DGK-derived PA is partially required for botrydial-induced ROS generation. Phosphatidic acid (PA) is a phospholipid second messenger involved in the induction of plant defense responses. It is generated via two distinct enzymatic pathways, either via phospholipase D (PLD) or by the sequential action of phospholipase C and diacylglycerol kinase (PLC/DGK). Botrydial is a phytotoxic sesquiterpene generated by the necrotrophic fungus Botrytis cinerea that induces diverse plant defense responses, such as the production of reactive oxygen species (ROS). Here, we analyzed PA and ROS production and their interplay upon botrydial treatments, employing tomato (Solanum lycopersicum) cell suspensions as a model system. Botrydial induces PA production within minutes via PLD and PLC/DGK. Either inhibition of PLC or DGK diminishes ROS generation triggered by botrydial. This indicates that PLC/DGK is upstream of ROS production. In tomato, PLC is encoded by a multigene family constituted by SlPLC1-SlPLC6 and the pseudogene SlPLC7. We have shown that SlPLC2-silenced plants have reduced susceptibility to B. cinerea. In this work, we studied the role of SlPLC2 on botrydial-induced PA production by silencing the expression of SlPLC2 via a specific artificial microRNA. Upon botrydial treatments, SlPLC2-silenced-cell suspensions produce PA levels similar to wild-type cells. It can be concluded that PA is a novel component of the plant responses triggered by botrydial.

Phenotypic Effects and Inhibition of Botrydial Biosynthesis Induced by Different Plant-Based Elicitors in Botrytis cinerea.

Botrytis cinerea is considered a model organism for the study of plant-pathogen interaction showing great genetic diversity and a high degree of morphological variability depending on environmental conditions. The use of new compounds and plant-based elicitors may trigger the expression of different B. cinerea genes, providing new sources of virulence factors. This work is focused on elucidating the phenotypic effect in B. cinerea of different carbon sources such as glucose, cellulose and tomato cell walls (TCW). Production of botrydial and dihydrobotrydial toxins was evaluated using thin-layer chromatography (TLC), proton nuclear magnetic resonance spectroscopy (1H-NMR) and mass spectrometry (UPLC-HRESIMS). Expression of the toxin biosynthesis gene BcBOT2 was followed using RT-qPCR. Results show an inhibition of the toxin biosynthesis pathway when TCW are present as a sole carbon source, suggesting that the toxin is only produced when rich molecules, like glucose, are available for fungal metabolism. That suggests a connection between gene expression of virulence factors and environmental conditions, where the silent genes can be induced by different culture conditions.

Atypical presentation of cervical necrotizing fasciitis: case report

Cervical necrotizing fasciitis (NF) is a soft tissue infection with a low incidence, characterized by rapid progression and high morbidity and mortality. The purpose of this report is to communicate the case of a patient diagnosed with cervical NF and its successful management. A 54-year-old male consulted after suffering from the condition for seven days. It was characterized by bilateral submandibular swelling, accompanied by fever, dysphagia, odynophagia, which were severely affecting the patient's general health. Physical examination revealed a painful, erythematous cervical swelling. A cervical computed tomography scan was performed, revealing a gaseous collection in the left mucosal pharyngeal space, extending to the glottis, associated with significant deep plane soft tissue emphysema onon the left side of the neck and with possible involvement of the danger space; pertinent lab findings include 19,190/uL leukocytes and 219mg/L CRP. Broad-spectrum antibiotic therapy was initiated with ceftriaxone and clindamycin. Exploratory surgery, lavage and drainage of the collected material were performed. Streptococcus anginosus was isolated by culture. The patient recovered appropriately showing improvement in clinical as well as in inflammatory parameters, being discharged on the ninth day. He is currently receiving periodical checkups in the surgery polyclinic

The formation of sesquiterpenoid presilphiperfolane and cameroonane metabolites in the Bcbot4 null mutant of Botrytis cinerea.

Botrytis cinerea is a polyphagous fungal parasite which causes serious damage to more than 200 plant species and consequent economic losses for commercial crops. This pathogen produces two families of phytotoxins, the botryanes and botcinins, which are involved in the infection mechanism. The B. cinerea genome has provided a complete picture of the genes involved in the biosynthesis of its secondary metabolites. The botrydial biosynthetic gene cluster has been identified. This cluster consists of seven genes, where the genes BcBOT1, BcBOT3 and BcBOT4 encode three mono-oxygenases. A study of the Bcbot4Δ null mutant revealed that this mono-oxygenase was involved in the hydroxylation at C-4 of the probotryane skeleton (C-11 of the presilphiperfolane skeleton). A detailed study of the Bcbot4Δ null mutant has been undertaken in order to study the metabolic fate of the presilphiperfolan-8-ol intermediate biosynthesized by this organism and in particular by this strain. As a result three new presilphiperfolanes and three new cameroonanes have been identified. The results suggest that the absence of the oxygen function at C-11 of the presilphiperfolane skeleton permits rearrangement to a cameroonane whilst hydroxylation at C-11 precludes this rearrangement. It is possible that the interactions of the C-11 hydroxylated derivatives perturb the stereo-electronic requirements for the migration of the C-11:C-7 sigma bond to C-8.