Chaetomium Cochliodes Research Articles

Bioprospecting Endophytic Fungi of Forest Plants for Bioactive Metabolites with Antibacterial, Antifungal, and Antioxidant Potentials.

The growing emergence of multi-drug resistant microbial strains has kept the scientific world searching for novel bioactive compounds with specific chemical characteristics. Accordingly, researchers have started exploring the understudied metabolites from endophytes as a new source of bioactive compounds. In this context, the current study was designed to evaluate the bioactive properties of endophytic fungi from the Mokrzański forest in Wrocław, Poland that have not yet been fully researched. Forty-three endophytic fungi were isolated from twelve distinct plants. Following their cultivation, fungal extracts were separately prepared from biomass and cell-free filtrates, and their antibacterial, antifungal (against human and plant pathogens), and antioxidant properties were examined. Five promising fungi after screening were identified to possess all of these activities. These strains and their respective plant hosts were Trichoderma harzianum BUK-T (Fagus sylvatica), Aspergillus ochraceus ROB-L1 (Robinia pseudoacacia), Chaetomium cochliodes KLON-L1, Fusarium tricinctum KLON-L2 (Acer platanoides), and Penicillium chrysogenum SOS-B2 (Pinus sylvestris). Moreover, gamma irradiation at several doses (Gy) was separately applied to the fungal cultures to study their effects on the recorded activities. Finally, compounds after preparative thin-layer chromatography fractionation of the five fungal strains were identified by GC-MS. These findings suggest that the isolated endophytic fungi could serve as novel sources of bioactive metabolites with antibacterial, antifungal, and antioxidant properties, potentially paving the way for future research and the development of new bioactive compounds.

Antibacterial potential of extracts and metabolites isolated from the endophytic fungus Chaetomium cochliodes against phytopathogenic bacteria

Summary Five fungal endophytes, Alternaria sp., Aspergillus sp., Chaetomium sp., Rhizopus sp. and Curvularia sp., were isolated from an Egyptian herbaceous plant, Tribulus terrestris, and tested for their antibacterial activity against three phytopathogenic bacteria (Pectobacterium carotovorum subsp. carotovorum, Ralstonia solanacearum, Pseudomonas syringae pv. syringae). Chaetomium sp. showed the highest antibacterial activity. This strain was identified morphologically and molecularly as Chaetomium cochliodes MS03 (MW898133) based on the ITS1-5.8S rRNA-ITS2 genomic region. Chaetomium cochliodes caused 15 and 8 mm inhibition zones of P. carotovorum subsp. carotovorum and R. solanacearum, respectively. Chaetomium cochliodes isolate was fermented and extracted with ethyl acetate. The crude extract of C. cochliodes showed strong antibacterial activity against P. carotovorum subsp. carotovorum (inhibition zone = 27 mm). Bioassay guided isolation of the crude extract using silica gel column chromatography was conducted to isolate bioactive secondary metabolites. Minimum inhibitory concentrations (MICs) were 500, 32 and 4 mg/L for C. cochliodes extract, fraction 14 and fraction 15, respectively, against P. carotovorum subsp. carotovorum. Bioactive fractions were analyzed by GC/MS. The bioactive pure compound was identified as 9,12-octadecadienoic acid (Z,Z) and the chemical structure was confirmed by H1 NMR and C13 NMR spectral analysis. The isolated compound showed a promising antibacterial activity against P. carotovorum subsp. carotovorum with MIC value of 32 mg/L.

UPLC-Q-TOF-MS/MS-Based Targeted Discovery of Chetomin Analogues from Chaetomium cochliodes.

Chetocochliodin M (5) containing a rare cage-ring and chetocochliodin N (6) featuring an unusual piperazine-2,3-dione ring system together with known analogues chetomin (1), chetoseminudin C (2), chetocochliodin I (3), and oidioperazine E (4) were targeted for purification from the fungus Chaetomium cochliodes using a UPLC-Q-TOF-MS/MS approach. The structures of the new compounds were elucidated using HR-ESI-MS, NMR, and ECD spectra. Compounds 1, 3, and 6 exhibited strong cytotoxic activities against A549 and HeLa cancer cell lines.

Reconstitution of the Early Stage of Chetomin Biosynthesis in Aspergillus fumigatus Leads to the Production of Epipolythiodioxopiperazines.

Using CRISPR-Cas9 technology and a microhomology-mediated end-joining repair system, we substituted genes of the gliotoxin pathway in Aspergillus fumigatus with genes responsible for chetomin biosynthesis from Chaetomium cochliodes, leading to the production of three new epipolythiodioxopiperazines (ETPs). This work represents the first successful endeavor to produce ETPs in a non-native host. Additionally, the simultaneous disruption of five genes in a single transformation marks the most extensive gene knockout event in filamentous fungi to date.

Composition of Culturable Microorganisms in Dusts Collected from Sport Facilities in Finland during the COVID-19 Pandemic.

Sport facilities represent extreme indoor environments due to intense cleaning and disinfection. The aim of this study was to describe the composition of the cultivated microbiota in dust samples collected in sport facilities during the COVID-19 pandemic. A dust sample is defined as the airborne dust sedimented on 0.02 m2 within 28 d. The results show that the microbial viable counts in samples of airborne dust (n = 9) collected from seven Finnish sport facilities during the pandemic contained a high proportion of pathogenic filamentous fungi and a low proportion of bacteria. The microbial viable counts were between 14 CFU and 189 CFU per dust sample. In seven samples from sport facilities, 20-85% of the microbial viable counts were fungi. Out of 123 fungal colonies, 47 colonies belonged to the potentially pathogenic sections of Aspergillus (Sections Fumigati, Nigri, and Flavi). Representatives of each section were identified as Aspergillus fumigatus, A. flavus, A. niger and A. tubingensis. Six colonies belonged to the genus Paecilomyces. In six samples of dust, a high proportion (50-100%) of the total fungal viable counts consisted of these potentially pathogenic fungi. A total of 70 isolates were considered less likely to be pathogenic, and were identified as Aspergillus section Nidulantes, Chaetomium cochliodes and Penicillium sp. In the rural (n = 2) and urban (n = 7) control dust samples, the microbial viable counts were >2000 CFU and between 44 CFU and 215 CFU, respectively, and consisted mainly of bacteria. The low proportion of bacteria and the high proportion of stress tolerant, potentially pathogenic fungi in the dust samples from sport facilities may reflect the influence of disinfection on microbial communities.

Acute Anti-Cancer Activity of Crude Extracts from two Endophytic Fungi Chaetomium cochliodes and Penicillium Sp. in Cancer Cell Lines and Mice

Acute Anti-Cancer Activity of Crude Extracts from two Endophytic Fungi Chaetomium cochliodes and Penicillium Sp. in Cancer Cell Lines and Mice

Aspergillus Was the Dominant Genus Found during Diversity Tracking of Potentially Pathogenic Indoor Fungal Isolates.

Viable airborne pathogenic fungi represent a potential health hazard when exposing vulnerable persons in quantities exceeding their resilience. In this study, 284 indoor fungal isolates from a strain collection of indoor fungi were screened for pathogenic potential through the ability to grow in neutral pH at 37 °C and 30 °C. The isolates were collected from 20 locations including 14 problematic and 6 non-problematic ordinary buildings. Out of the screened isolates, 170 isolates were unable to grow at 37 °C, whereas 67 isolates growing at pH 7.2 at 37 °C were considered as potential opportunistic pathogens. Forty-seven isolates growing at 30 °C but not at 37 °C were considered as less likely pathogens. Out of these categories, 33 and 33 strains, respectively, were identified to the species level. The problematic buildings included known opportunistic pathogens: Aspergillus calidoustus, Trichoderma longibrachiatum, Rhizopus arrhizus and Paecilomyces variotii, as well as less likely pathogens: Aspergillus versicolor, Chaetomium cochliodes, Chaetomium globosum and Chaetomium rectangulare. Opportunistic pathogens such as Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger and Aspergillus tubingensis and less likely pathogens such as Aspergillus westerdijkiae, Chaetomium globosum and Dichotomopilus finlandicus were isolated both from ordinary and from problematic buildings. Aspergillus was the dominant, most diverse genus found during screening for potentially pathogenic isolates in the indoor strain collection. Studies on Aspergillus niger and Aspergillus calidodoustus revealed that tolerance to cleaning chemicals may contribute to the adaptation of Aspergillus species to indoor environments.

Investigation of chetomin as a lead compound and its biosynthetic pathway.

Chaetomium fungi produce a diversity of bioactive compounds. Chaetomium cochliodes SD-280 possesses 91 secondary metabolite gene clusters and exhibits strong antibacterial activity. One of the active compounds responsible for that activity, chetomin, has a minimum inhibitory concentration (MIC) for anti-methicillin-resistant Staphylococcus aureus (MRSA) of 0.05μg/mL (vancomycin: 0.625μg/mL). This study demonstrated that the addition of glutathione (GSH) can enhance chetomin yield dramatically, increasing its production 15.43-fold. Following genome sequencing, cluster prediction, and transcriptome and proteome analyses of the fungus were carried out. Furthermore, a relatively complete chetomin biosynthetic gene cluster was proposed, and the coding sequences were acquired. In the cluster of GSH-treated cells, proteome analysis revealed two up-regulated proteins that are critical enzymes for chetomin biosynthesis. One of these enzymes, a nonribosomal peptide synthetase (NRPS), was heterologously expressed in Aspergillus nidulans, and one of its metabolites was determined to be an intermediate in the chetomin biosynthetic pathway. We present here, to our knowledge, the first experimental evidence that chetomin exhibits strong bioactivity against MRSA. Our work also provides extensive insights into the biosynthetic pathway of chetomin, in particular identifying two key enzymes (glutathione S-transferase (CheG) and NRPS (CheP)) that substantially up-regulate chetomin. These mechanistic insights into chetomin biosynthesis will provide the foundation for further investigation into the anti-pathogenic properties and applications of chetomin. KEY POINTS: • Chetomin exhibits strong anti-MRSA activity with MIC of 0.05μg/mL. • Addition of glutathione improved the yield of chetomin by 15.43-fold. • CheG and CheP involved in the chetomin biosynthesis were revealed for the first time.

The Microflora of Maize Grains as a Biological Barrier against the Late Wilt Causal Agent, Magnaporthiopsis maydis

The maize pathogen Magnaporthiopsis maydis causes severe damage to commercial fields in the late growth stages. This late wilt disease has spread since its discovery (the 1980s) and is now common in most corn-growing areas in Israel. In some fields and sensitive plant species, the disease can affect 100% of the plants. The M. maydis pathogen has a hidden endophytic lifecycle (developed inside the plants with no visible symptoms) in resistant corn plants and secondary hosts, such as green foxtail and cotton. As such, it may also be opportunist and attack the host in exceptional cases when conditions encourage it. This work aims to study the pathogen’s interactions with maize endophytes (which may play a part in the plant’s resistance factors). For this purpose, 11 fungal and bacterial endophytes were isolated from six sweet and fodder corn cultivars with varying susceptibility to late wilt disease. Of these, five endophytes (four species of fungi and one species of bacteria) were selected based on their ability to repress the pathogen in a plate confrontation test. The selected isolates were applied in seed inoculation and tested in pots in a growth room with the Prelude maize cultivar (a late wilt-sensitive maize hybrid) infected with the M. maydis pathogen. This assay was accompanied by real-time qPCR that enables tracking the pathogen DNA inside the host roots. After 42 days, two of the endophytes, the Trichoderma asperellum, and Chaetomium subaffine fungi, significantly (p < 0.05) improved the infected plants’ growth indices. The fungal species T. asperellum, Chaetomium cochliodes, Penicillium citrinum, and the bacteria Bacillus subtilis treatments were able to reduce the M. maydis DNA in the host plant’s roots. Studying the maize endophytes’ role in restricting the invasion and devastating impact of M. maydis is an essential initial step towards developing new measures to control the disease. Such an environmentally friendly control interface will be based on strengthening the plants’ microbiome.

FUNGAL PATHOGENS OF TOMATO IN SOUTH-WESTERN RUSSIA
 (KRASNODAR TERRITORY)

During a study of fungal diseases of tomato in the South of Russia (Krasnodar Territory) 56 fungal isolates associated with tomato fruits were obtained. Most of them belonged to the species Alternaria alternata. Alternaria solani, Fusarium equiseti, Phomopsis phaseoli, Chaetomium cochliodes, Clonostachys sp., Irpex lacteus, Colletotrichum coccodes were also identified. Laboratory experiments revealed that Clonostachys sp., C. сochliodes, P. phaseoli, I. lacteus, and F. equiseti developed well on the fruit’s slices. Fusarium equiseti was the only species that can penetrate the tomato through epidermis and infect entire fruit. The most effective fungicide against F. equiseti was difenoconazole (EC50 = 0.08 mg/L); pencycuron was also effective (EC50 = 32.5 mg/L). Thiabendazole completely inhibited the growth of F. equiseti at the concentration 100 mg/L (EC50 = 47 mg/L).

Fungal diversity in tomato (Solanum lycopersicum) leaves and fruits in Russia

Sequencing of cloned PCR-amplified species-specific rDNA fragments and isolation of axenic cultures from tomato fruits was carried out to study the mycobiota of tomato leaves and fruits in European part of Russia. DNA was extracted from the leaves, and library of ITS region fragments was constructed in E. coli by cloning of PCR products. This survey revealed fourteen species associated with disease-affected leaves: Septoria lycopersici, Fulvia fulva (=Cladosporium fulvum), Didymella glomerata (=Phoma glomerata), Cladosporium herbarum, Podosphaera fusca, Neocamarosporium goegapense (=Phoma betae), Rhizoctonia solani, Candida albicans, Dioszegia hungarica, Cladosporium cladosporioides, Didymella lycopersici, Alternaria infectoria, Alternaria alternata, Cryptococcus tephrensis. In the leaves from healthy plants without any visible symptoms DNA of three species was found: Aspergillus versicolor, Alternaria alternata, Aureobasidium pullulans. Analysis of axenic cultures isolated from green diseased tomato fruits revealed fungal species: Alternaria alternata, Alternaria solani, Phomopsis phaseoli, Fusarium equiseti, Chaetomium cochliodes, Clonostachys sp., Irpex lacteus, Colletotrichum coccodes. This research provides new information on the mycobiota of tomato in Southern Russia, the main tomato producing region of the country.

Економічна та біоенергетична ефективність комплексної передпосівної обробки насіння гречки Хетоміком та Діазобактерином

The purpose. To give economic and power assessment of joint application of microbial specimens Khetomic and Diazobacterin in technique of growing of buckwheat of sowing campaign. Methods. Field experiments were spent according to the conventional methodical recommendations. Economic and power efficiency of presowing treatment of seeds of buckwheat microbial specimens Khetomic (bioagent — Chaetomium cochliodes 3250) and Diazobacterin (bioagent — Azospirillum brasilense 18-2) was determined according to basic methodical approaches based on comparison of result got from certain agricultural method with expenditures for its holding. The prices for resources and agricultural products are taken at average actual level on 2017 according to available statistical data. For assessment of reliability of differences between alternatives of experiments they evaluated the least essential variance. Results. By three-year field experiments it is determined that increase of yield in case of preseeding inoculation with Diazobacterin makes 20,6%, presowing treatment with Khetomic — 22 %. The highest result of complex application of microbial specimens — 34,9%. Presowing treatment of seeds of buckwheat with Khetomic and Diazobacterin decreased cost price of a unit of production on 1026 hrn/t, increased conditional profit on 7463 hrn counting upon 1 hectare of the area of sowing, and also raised rated level of profitableness of production of grain of buckwheat on 79,0% that ensured pay-back of additional expenditures with profit at the level of 36,95 hrn/hrn. The quotient of power efficiency at complex use of microbial specimens made 3,64. Thus energy content of yield of buckwheat increased on 12167 MJ/hectare due to heightening exit of produce. Conclusions. On the basis of results of long-term field and farm experiments it is offered to farm-producers to use complex presowing treatment of seeds of buckwheat with microbial specimens Khetomic and Diazobacterin. That is economically and energetically expedient in technique of cultivation of crop.

Expression of extracellular peroxidases and catalases in mesophilic and thermophilic Chaetomia in response to environmental oxidative stress stimuli

Peroxidases and catalases are well-known antioxidant enzymes produced in almost all living organisms for the elimination of reactive oxygen species (ROS) and thus they prevent the occurrence of oxidative stress. In our study we focused on two soil fungi of the family Chaetomiaceae (mesophilic Chaetomium cochliodes and its thermophilic counterpart C. thermophilum var. dissitum) in order to explore the presence of peroxidase and catalase genes, formation of their native transcripts and protective effect of corresponding translation products in a case study. Predicted genes of our interest were confirmed by genomic PCR and their inducible transcripts by RT-PCR. We were able to quantify the expression levels of newly discovered fungal heme peroxidases and catalases with the reverse-transcription quantitative real-time PCR method. We compared obtained quantitative levels of mRNA production with the level of corresponding extracellular protein occurrence as detected with monitoring their specific peroxidase and catalase activities directly in the cultivation media at optimal growth temperatures. The presence of secretory Catalase 2 from C. thermophilum var. dissitum was detected and identified with mass spectrometry approach directly in the growth medium. This unique catalase is phylogenetically closely related with a previously described catalase-phenol oxidase thus representing an effective and versatile antioxidant in the environment of the fungal mycelia also involved in the catabolism of recalcitrant phenolic substances.

Coprophilous fungi from Brazil: new records for the Neotropics

Twelve ascomycetes associated with herbivore dung, collected throughout an edaphic and climatic gradient from the Atlantic Forest complex to the semi-arid Caatinga in Pernambuco, Northeastern Brazil, represent new records: Ascobolus castaneus, Arnium hirtum, Cercophora anisura, Chaetomium citrinum, C. spirale, Coniochaeta philocoproides, Coprotus albidus, and Delitschia vulgaris are new records for the Neotropics; Cercophora sordarioides, Chaetomium cochliodes, Sordaria lappae, and Thelebolus microsporus are new records for Brazil. Ascobolus castaneus is recorded for the second time worldwide, revealing a much wider geographical distribution for a species previously reported only from China. Descriptions and updated geographic distributions are presented, and information regarding the records is discussed.

Chetomin induces apoptosis in human triple-negative breast cancer cells by promoting calcium overload and mitochondrial dysfunction

Human triple-negative breast cancer (TNBC) is poorly diagnosed and unresponsive to conventional hormone therapy. Chetomin (CHET), a fungal metabolite synthesized by Chaetomium cochliodes, has been reported as a promising anticancer and antiangiogenic agent but the complete molecular mechanism of its anticancer potential remains to be elucidated. In our study, we explored the anti-neoplastic action of CHET on TNBC cells. Cytotoxicity studies were performed in human TNBC cells viz. MDA-MB-231 and MDA-MB-468 cells by Sulforhodamine B assay. It exhibited antiproliferative response and induced apoptosis in both the cell types. Cell cycle analysis revealed that it increases the sub G0/G1 phase cell population. Modulation of mitochondrial membrane potential, activation of caspase 3/7 and a remarkable increase in the expression of cleaved PARP and increased chromatin condensation was observed after CHET treatment in MDA-MB-231 and MDA-MB-468 cells. Additionally, an elevated level of intracellular Ca2+ played an important role in CHET mediated cell death response. Calcium overload in mitochondria led to release of cytochrome c which in turn triggered caspase-3 mediated cell death. Inhibition of calcium signalling using BAPTA-AM reduced apoptosis confirming the involvement of calcium signalling in CHET induced cell death. Chetomin also inhibited PI3K/mTOR cell survival pathway in human TNBC cells. The overall findings suggest that Chetomin inhibited the growth of human TNBC cells by caspase-dependent apoptosis and modulation of PI3K/mTOR signalling and could be used as a novel chemotherapeutic agent for the treatment of human TNBC in future.

The impact of farming practices on the productivity of soybean

The article describes research results of agroecological factors set, their impact on the productivity of soy and reactions to them of modern varieties in the western forest-steppe zone of Ukraine. Compositions of microorganisms which enable to accelerate the growth and development of plants, reduce the spread of disease, increase productivity and improve product quality were used. The influence of green manure on the growth and development of soybean plants was investigated. The positive effect on the crop capacity and quality of soybean seeds, when at the crop flowering stage spraying the microbial preparation Hetomik based on strain Chaetomium cochliodes, was established. Different reactions of studied soybeans varieties were found. The most sensitive to factors of influence were varieties of Georgiana and Angelica. The plants of these varieties have formed larger amount of beans, high-quality seeds, nodules on the root system, area of a leaf surface and increased weight nodules on the roots of one plant and weight of 1000 seeds. It was established that in western forest steppe zone seeds of soybean varieties were appropriate to make Inoculation of rhizobia strains 634B and M-8 before sowing on the background making to the soil green manure. Crops of specified varieties are recommended to spray in the flowering stage with biopreparation Hetomik at a dose of 100 ml/ha, using a working solution of 250 l/ha

CELLULOLYTIC ACTIVITY OF ANTAGONIST MOULD CHAETOMIUM COCHLIODES, BIO-AGENT OF MICROBIAL PREPARATION KHETOMIK

Cellulolytic activity of antagonist mould Chaetomium cochliodes 3250 has been investigated. It was shown that C. cochliodes 3250 synthesizes complex of cellulases – degradation enzymes of cell wall. The highest parameters of endo, exoglucosidase and β- glucosidase activity of mould are shown at Day 9 of cultivation. High cellulase activity causes the ability of mould to penetrate plant tissues. C. cochliodes 3250, which was introduced in the root zone of buckwheat seeds, forms fruiting bodies on the surface of root fibrils and penetrates cells of rhizodermis.

Nitrogen-fixing microbial grouping of the root zone and buckwheat productivity under the influence of fungus Chaetomium cochliodes

It was established that treatment of buckwheat seeds with soil saprotroph mould Chaetomium cochliodes 3250 contributes to increase the number of N2-fixing bacteria in cropsroot zone. Thus, the number of Azospirillum and Azotobacter cell was getting more in rhizosphere soil. The number of all studied ecological-trophic bacteria groups was getting more on the root surface simultaneously with N2-fixation process intensification. Nitrogenase activity had grown in 1.3 times in rhizosphere soil and in 11.3 times on the root surface.The mold usage seemed to be positive to rise up the buckwheat harvest by 12.6%.

Genome sequence of the filamentous soil fungus Chaetomium cochliodes reveals abundance of genes for heme enzymes from all peroxidase and catalase superfamilies.

BackgroundThe ascomycetous family Chaetomiaceae (class Sordariomycetes) includes numerous soilborn, saprophytic, endophytic and pathogenic fungi which can adapt to various growth conditions and living niches by providing a broad armory of oxidative and antioxidant enzymes.ResultsWe release the 34.7 Mbp draft genome of Chaetomium cochliodes CCM F-232 consisting of 6036 contigs with an average size of 5756 bp and reconstructed its phylogeny. We show that this filamentous fungus is closely related but not identical to Chaetomium globosum and Chaetomium elatum. We screened and critically analysed this genome for open reading frames coding for essential antioxidant enzymes. It is demonstrated that the genome of C. cochliodes contains genes encoding putative enzymes from all four known heme peroxidase superfamilies including bifunctional catalase-peroxidase (KatG), cytochrome c peroxidase (CcP), manganese peroxidase, two paralogs of hybrid B peroxidases (HyBpox), cyclooxygenase, linoleate diol synthase, dye-decolorizing peroxidase (DyP) of type B and three paralogs of heme thiolate peroxidases. Both KatG and DyP-type B are shown to be introduced into ascomycetes genomes by horizontal gene transfer from various bacteria. In addition, two putative large subunit secretory and two small-subunit typical catalases are found in C. cochliodes. We support our genomic findings with quantitative transcription analysis of nine peroxidase & catalase genes.ConclusionsWe delineate molecular phylogeny of five distinct gene superfamilies coding for essential heme oxidoreductases in Chaetomia and from the transcription analysis the role of this antioxidant enzymatic armory for the survival of a peculiar soil ascomycete in various harsh environments.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3111-6) contains supplementary material, which is available to authorized users.

The Early Challenges of Antibiotic Discovery

Professor Kim Lewis' excellent review of the status of antibiotic research (“Challenges of Antibiotic Discovery,” Microbe, September 2015, p. 363–369) unfortunately includes a common microbiological misconception that should be addressed. He comments that Selman Waksman “introduced a simple screen which essentially replicates the accidental discovery of Fleming—a Streptomyces spot-inoculated on a plate with a lawn of the test pathogen, and a zone of growth inhibition indicates the presence of an antibiotic.” However, the variety of complex twists and turns of screening for antibiotics are illustrated by the theses of the following students of Waksman's and not readily apparent from the published papers: H. Boyd Woodruff (actinomycin)(H. B. Woodruff, The production of antibiotic substances by soil microorganisms. Ph.D. Thesis, Rutgers, the State University of New Jersey, New Brunswick, N.J., 1942), Elizabeth Horning (clavacin and fumigacin)(E. S. Horning, Distribution and properties of antagonistic fungi and actinomycetes in nature. Ph.D. Thesis, Rutgers, the State University of New Jersey, New Brunswick, N.J., 1942), Doris Jones (antiviral screen)(D. Jones, The effect of micro-organisms and antibiotic substances upon viruses. M.S. Thesis, Rutgers, the State University of New Jersey, New Brunswick, N.J., 1945), Elizabeth Bugie (antibiotic production)(E. J. Bugie, Production of antibiotic substances by Aspergillus flavus and Chaetomium cochliodes, M.S. Thesis, Rutgers, the State University of New Jersey, New Brunswick, N.J., 1944), and Albert Schatz (streptomycin)(A. Schatz, Streptomycin, an antibiotic agent produced by Actinomyces griseus. Ph.D. Thesis, Rutgers, the State University of New Jersey, New Brunswick, N.J., 1945). In 1952 the Nobel Committee awarded the Nobel Prize in Physiology or Medicine to Selman Waksman for his “ingenious systematic and successful studies of soil microbes that led to the discovery of streptomycin.” Likewise, this year the Nobel Prize in Physiology or Medicine was in part awarded to Satoshi mura for the discovery of Avermectin, and the Nobel Assembly cited Dr. mura's “extraordinary skills in developing unique methods” for the isolation of Streptomyces species. Screening methodology merits focus.