Plant metabolite 5-pentadecyl resorcinol is produced by the Amazonian fungus Penicillium sclerotiorum LM 5679

Since the classic studies of Alexander Flemming, Penicillium strains have been known as a rich source of antimicrobial substances. Recent studies have identified novel metabolites produced by Penicillium sclerotiorum that have antibacterial, antifouling and pharmaceutical activities. Here, we report the isolation of a P. sclerotiorum (LM 5679) from Amazonian soil and carry out a culture-based study to determine whether it can produce any novel secondary metabolite(s) that are not thus-far reported for this genus. Using a submerged culture system, secondary metabolites were recovered by solvent extract followed by thin-layer chromatography, nuclear magnetic resonance, and mass spectroscopy. One novel secondary metabolite was isolated from P. sclerotiorum (LM 5679); the phenolic compound 5-pentadecyl resorcinol widely known as an antifungal, that is produced by diverse plant species. This metabolite was not reported previously in any Penicillium species and was only found once before in fungi (that time, in a Fusarium). Here, we discuss the known activities of 5-pentadecyl resorcinol in the context of its mode-of-action as a hydrophobic (chaotropicity-mediated) stressor.

3D Series Metal Complexes Containing Schiff Base Ligand with 2,2'-Bipyridine: Synthesis, Characterization and Assessment of Antifungal Activity

The rapid increase in the number of multidrug-resistant of most pathogenic organisms is fast becoming a global concern, thus, the discovery of novel active pharmacological compounds against new targets is a matter of urgency. The incorporation of metal ions into organic ligands has introduced metal-organic drugs framework with synergistic effects for novel applications in the biological system. In this research work, metal(II) chloride complexes of copper, nickel and zinc containing methylphenylketone thiosemicarbazone (MPK-TSC) with 2,2’-bipyridine (bipy) were synthesized; they were further characterized by satisfactory microelemental analysis, Fourier Transform InfraRed (FTIR) spectra as well as electronic spectra study. The complexes are proposed to have the formulae [L1ML2(Cl2)] where M=metal ion, L1=methylphenylketone thiosemicarbazone L2=2,2’-bipyridine. The complexes are of 1:2 (metal:ligand) stoichiometry and non-electrolytes in solution, the bidentate nature of the two ligands was evident from the FTIR spectra. The compounds were screened for their antifungal activity against four pathogenic fungi: Aspergillus niger, Penicillium Species, Rizopus and Candida albicans using disc diffusion method. The activities of the complexes have been found to be greater than those of the metal salts and the uncoordinated ligands.

Two New Penicillium Species Penicillium Dongtaiense Sp. Nov and Penicillium Yanchengense sp. nov., Isolated From a Poplar Plantation in China

Studies on the degradation of plant cell wall polysaccharides by fungal extracellular enzymes have attracted much recent attention. In this study, dozens of fungus species spanning genera were isolated from rotting leaves based on their ability to decompose xylan. Using genetic sequencing (rDNA internal transcribed spacer), strains were identified as members of the genera Aspergillus, Penicillium, Alternaria, Campylocarpon, Pyrenochaeta and Cladosporium. Among these strains, two Penicillium strains can’t be assigned to any reported species. In this study, they are described new species as Penicillium yanchengium sp. novT (AF 2021051) and Penicillium dongtaiense sp. novT (AF 2121001) based on multigene phylogenetic analysis and morphology. Penicillium yanchengense sp. novT belong to Penicillium section Lanata-Divaricata and are phylogenetically closely related to Penicillium oxalicum and Penicillium asturianum. Isolates of Penicillium yanchengense sp. novT have a faster growth on Czapek yeast agar (CYA) at 37 ℃, abundant exudate present on CYA, and a greater ability to produce acid on creatine sucrose agar (CREA). Penicillium dongtaiense sp. novT was placed in section Sclerotiora and it is most closely related to Penicillium exsudans, Penicillium mallochii and Penicillium acidum. It is unique in slower growth on CYA and MEA plates, abundant exudate on MEA, and cerebriform grooves on YES compared to its relatives. In this study, we provide detailed description about two species.

Non-viral Microbial Keratitis in a Tertiary Care Hospital in Bangladesh

Introduction: Microbial keratitis is a serious ocular infectious disease that can lead to significant visual loss and ophthalmic morbidity. Objectives were to see the profile of non-viral microbial keratitis in a tertiary care hospital in Bangladesh. Materials and Methods: This cross-sectional study was conducted in the Department of Ophthalmology, Sylhet MAG Osmani Medical College Hospital, Sylhet between January 2015 and December 2016. Results: The mean age of the patients was 46.7 ± 16.5 years with male preponderance (54.4%). The most common predisposing factors were trauma (66.7%), and chronic dacryocystitis (25.6%). Fungal growth was more frequent compared to bacterial growth 70 (77.7%) versus 30 (33.3%), p<0.01). Gram positive organisms were Staphylococcus epidermidis (11.1%), Staphylococcus aureus (3.3%); gram negative organisms were Pseudomonas aeruginosa (12.2%), Klebsiella species (3.3%) and Escherichia coli (3.3%). Aspergillus species (71.4%) was the commonest fungus. Others were Penicillium species (7.1%), Fusarium species (8.6%), Mucor (10.0%) and Rhizopus (2.9%). Conclusion: Fungi are more frequent cause of non-viral keratitis. Watering, redness, pain or burning sensation, corneal opacity and dimness of vision are clinical profiles of non-viral microbial keratitis. Medicine Today 2021 Vol.33(2): 133-137

INCIDENCE OF TOXIGENIC MOULDS IN FOOD SPICES SOLD IN OPEN MARKETS IN BENIN CITY, NIGERIA

Spices are parts of plants or plant substances primarily used for flavouring and preservation of food. Spices can be exposed to microbial contamination and toxic substances such as mycotoxins during processing storage and distribution. The aim of the study was to determine the incidence of toxigenic moulds in food spices sold in open markets in Benin City. A total of 35 samples were obtained from three markets. Potato dextrose agar (PDA) and Aspergillus flavus and parasiticus agar (AFPA) were employed for the isolation, characterization and identification of fungal isolates using standard microbiological procedures. The pH was determined using an electronic pH meter, titratable acidity and moisture content were also determined using appropriate methods. Fungi isolated in this study included; Fusarium sp., Alternaria sp., Rhizopus sp., Geotrichum sp., Cladosporium sp., Aspergillus niger and Penicillium sp. The most occurring fungus was Fusarium sp. (26%) while Alternaria sp. (2%) was the least occurring fungus. The fungal load ranged from 0.33 - 28.67 x 103 sfu/g and the pH values of samples ranged from 4.83 – 5.67. The titratable acidity ranged from 0.037 – 0.521 mg/l, while the moisture content ranged from 2.0 – 28.0%. The study revealed the presence of toxigenic moulds such as Fusarium and Penicillium species in food spices sold in open markets. This may have resulted from improper storage, handling and poor sanitary conditions in the open markets.

Occurrence and Characterization of Penicillium Species Isolated from Post-Harvest Apples in Lebanon

The apple is one of the most important fruit tree crops in the Mediterranean region. Lebanon, in particular, is among the top apple producer countries in the Middle East; however, recently, several types of damage, particularly rot symptoms, have been detected on fruits in cold storage. This study aims to identify the causal agents of apple decay in Lebanese post-harvest facilities and characterize a set of 39 representative strains of the toxigenic fungus Penicillium. The results demonstrated that blue mould was the most frequent fungal disease associated with apples showing symptoms of decay after 3–4 months of storage at 0 °C, with an average frequency of 76.5% and 80.6% on cv. Red and cv. Golden Delicious apples, respectively. The morphological identification and phylogenetic analysis of benA gene showed that most Penicillium strains (87.2%) belong to P. expansum species whereas the remaining strains (12.8%) belong to P. solitum. Furthermore, 67.7% of P. expansum strains produced patulin when grown on apple puree for 14 days at 25 °C with values ranging from 10.7 mg kg−1 to 125.9 mg kg−1, whereas all P. solitum did not produce the mycotoxin. This study highlights the presence of Penicillium spp. and their related mycotoxin risk during apple storage and calls for the implementation of proper measures to decrease the risk of mycotoxin contamination of apple fruit products.

Differentiation of Penicillium roqueforti from Closely Related Species Contaminating Cheeses and Dairy Environment

Currently, Penicillium roqueforti and the closely related P. carneum and P. paneum are identified based on their macromorphology, micromorphology, and molecular properties, the determination of which involves time-consuming procedures. Culture collections focused on dairy isolates of P. roqueforti require quick and efficient tools for routine applications to identify the (a) taxonomy affiliation and (b) morphological properties of strains that influence the sensory properties of blue-veined cheeses. Here, we assessed the morphological variability of P. roqueforti, P. carneum, P. paneum, and P.crustosum on artificial, Edam-like, and Roquefort-like media. Molecular tools were used to test P. roqueforti strains and clones effectively. A novel primer, PrsF, was tested for specificity within strains and isolates of P. roqueforti compared to P. carneum, P. paneum, and P. crustosum. The results reveal that PrsF was specific to the P. roqueforti samples and did not amplify the other tested Penicillium species. Identification based simultaneously on the specificity of the PrsF primer pair and cultivation of P. roqueforti strains on Roquefort-like medium represents an effective method for expanding the collections and practical use of P. roqueforti in the dairy industry.

Effect of chitosan and silicon oxide treatments on postharvest Valencia Late (Citrus × sinensis) fruits

The efficacy of chitosan and silicon oxide to prevent postharvest weight loss and fungi infection in 'Valencia Late' oranges was tested. Three silicon oxide concentrations (0.1%, 0.2%, 1%) were applied as preharvest treatments. Chitosan treatments were performed at the same concentrations in postharvest fruit. Preharvest applications were carried out by tractor spraying, while fruit were submerged for 30 seconds in baths with the chitosan concentrations in the postharvest applications. In both cases, a positive control (water treatment) and negative control (fungicide) were included. Treated fruit were stored in a chamber to simulate commercial storage conditions (4 ºC, 90% RH) for 9 weeks. After this time, the weight loss and damage caused by fungi due to natural infection were evaluated. Both silicon oxide and chitosan applications were effective in controlling natural infection by Penicillium species but had no positive effect on weight loss.

Polyphasic taxonomic characterization of nine Penicillium species from soil of different parts of India

Aim: Morpho-molecular analyses for taxonomic characterization of nine predominant Penicillium species present in the soil of different parts of India. Methodology: Fifteen Penicillium isolates were isolated from the soil samples collected from the experimental field of ICAR-Indian Agricultural Research Institute (IARI), New Delhi. Another twenty-six isolates were procured from Indian Type Culture Collection (ITCC), Division of Plant Pathology, ICAR-IARI, New Delhi which were isolated from the soil of different parts of India. Total 41 isolates were characterized following distinct macroscopic (colony texture, colony colour exudate production; soluble pigmentation; reverse coloration and mycelial growth) and microscopic observations (type of penicillus; shape of phialides; conidial shape, size and pigmentation). Molecular characterization was done using partial β-tubulin gene sequence which is considered an excellent marker in differentiating Penicillium species. Results: The morphological data in species description perfectly matched with molecular data generated using β-tubulin gene marker and nine different species viz., P. aethiopicum, P. chrysogenum, P. crustosum, P. janthinellum, P. mononematosum, P. oxalicum, P. polonicum, P. singorense and Talaromyces pinophilus (Syn. P. pinophilum) were confirmed. Interpretation: Above nine Penicillium species are found predominantly in the soil collected from different parts of India. The β-tubulin gene can be considered as an excellent marker to differentiate Penicillium species as confirmed from this study. The combined morpho- molecular analyses can be further utilized to delineate morphologically similar Penicillium species and also helpful to establish new species of Penicillium.

Molecular Identification and Phylogenetic Study of a Novel Pravastatin-producing Fungal Strain

Pravastatin is a cholesterol-lowering agent of high therapeutic value which is obtained based on a twostep production process. The development of one-step fermentation process based on pravastatin-producing microfungi could be advantageous. We isolated a number of soil microfungi and screened them for pravastatin production. Among them, the isolate ESF21 was selected as an active pravastatin producer. The aim of the present study was to identify this isolate to species level and to investigate pravastatin accumulation by this microfungus. As a result, a range of standard macro- and micro-morphological characters of the ESF21 strain was documented. The isolate ESF21 was a member of the genus Penicillium. Based on the results of molecular characterization, the isolated culture was identified as Penicillium brefeldianum ESF21. To analyze the phylogenetic relationships between this microfungus and other Penicillium species, a phylogenic tree was constructed. When the time course of pravastatin production by the identified strain was investigated, the maximum level of pravastatin (196.83 mg/L) was accumulated after 10 days of fermentation. The identified strain has a scientific interest as a previously unknown wild-type fungal producer of pravastatin.