1.Molecular characterization of mycotoxin-producing Aspergillus parasiticus and sensitivity pattern to different disinfectants
Zunira Mughis ; Muhammad Asad Ali ; Aftab Ahmad Anjum ; Muhammad Ovais Omer ; Mateen Abbas ; Maria Najeeb
Malaysian Journal of Microbiology 2022;18(5):524-532
Aims:
The study was aimed to isolate and characterize the mycotoxin-producing filamentous Aspergillus parasiticus from the feed samples. The sensitivity pattern of the isolates was assessed against different disinfectants.
Methodology and results:
Fifty different feed samples were screened for A. parasiticus isolation. Isolates were subjected to macroscopic and microscopic characterization. Polymerase chain reaction was performed to confirm the isolates at the genomic level. Mycotoxin producing potential of the isolates was assessed by thin-layer chromatography (TLC). To quantify the toxins, high performance liquid (HPLC) was employed. The antifungal potential of disinfectants was determined by the well diffusion method followed by minimum inhibitory concentration (MIC) calculation. Out of twenty isolates of A. parasiticus, 11(55%) isolates were observed positive for toxin production. Three toxigenic isolates (AspP2, AspP4 and AspP8) were selected to evaluate their susceptibility against disinfectants by well diffusion method. AspP2 produced maximum (5.90 ng/mL) toxin, followed by AspP4 (3.11 ng/mL) and AspP8 (18.47 ng/mL). Terralin showed maximum fungicidal activity with 29.66 ± 8.08 mm zone of inhibition at 0.42 μg/mL MIC. Hypochlorite and Instru Star showed 99% disinfection with 30, 60 and 90 min contact time (6 mean log reduction) for all A. parasiticus isolates. Alpha Guard inhibited growth after 15 min contact time for all the isolates.
Conclusion, significance and impact of study
This study provides data indicating the contamination of feed samples with mycotoxin-producing A. parasiticus isolates and their sensitivity against commercially available disinfectants. Use of these disinfectants in appropriate concentrations and time could help prevent the contamination of food, feed and healthcare settings with the fungal species.
Mycotoxins
;
Aspergillus
2.Screening of zearalenone-degrading bacteria and analysis of degradation conditions.
Tao DENG ; Qing-Song YUAN ; Tao ZHOU ; Lan-Ping GUO ; Wei-Ke JIANG ; Shi-Hua ZHOU ; Chang-Gui YANG ; Chuan-Zhi KANG
China Journal of Chinese Materia Medica 2021;46(20):5240-5246
Zearalenone(ZEN) is a mycotoxin produced by Fusarium, possessing estrogen-like effects, carcinogenicity, and multiple toxicities. To seek more efficient and practical agents for biological detoxification and broaden their application, this study isolated 194 bacterial strains from the moldy tuberous root of Pseudostellaria heterophylla, which were co-cultured with ZEN. An efficient ZEN-degrading strain H4-3-C1 was screened out by HPLC and identified as Acinetobacter calcoaceticus by morphological observation and molecular identification. The effects of culture medium, inoculation dose, culture time, pH, and temperature on the degradation of ZEN by H4-3-C1 strain were investigated. The mechanism of ZEN degradation and the degrading effect in Coicis Semen were discussed. The degradation rate of 5 μg·mL~(-1) ZEN by H4-3-C1 strain was 85.77% in the LB medium(pH 6) at 28 ℃/180 r·min~(-1) for 24 h with the inoculation dose of 1%. The degradation rate of ZEN in the supernatant of strain culture was higher than that in the intracellular fluid and thalli. The strain was inferred to secret extracellular enzymes to degrade ZEN. In addition, the H4-3-C1 strain could also degrade ZEN in Coicis Semen. If the initial content of ZEN in Coicis Semen was reduced from 90 μg·g~(-1) to 40.68 μg·g~(-1), the degradation rate could reach 54.80%. This study is expected to provide a new strain and application technology for the biological detoxification of ZEN in food processing products and Chinese medicinal materials.
Bacteria
;
Fusarium
;
Mycotoxins
;
Temperature
;
Zearalenone
3.Physiological Characteristics of Green Mold (Trichoderma spp.) Isolated from Oyster Mushroom (Pleurotus spp.).
In Young CHOI ; Gi Tae JOUNG ; Joung RYU ; Joung Sik CHOI ; Yeong Geun CHOI
Mycobiology 2003;31(3):139-144
This study was conducted to investigate physiological characteristics of Trichoderma spp. isolated from Pleurotus spp. Damage tests of Pleurotus spp. and mycotoxins tests of Trichoderma spp. were also done. The optimal growth temperature of Trichoderma spp. was 27~30degrees C. Although, T. longibrachiatum was able to grow at 37degrees C and grew 30~40 times faster than Pleurotus. The colony colour on PDA medium of T. cf. virens was yellowish green, T. longibrachiatum was yellow, and T. harzianum was turning to bright green. In damage tests of Pleurotus by Trichoderma, T. cf. virens caused the most severe damage to Pleurotus. T. longibrachiatum and T. harzianum caused less damage on Pleurotus but were able to cause greater damage to P. eryngii. One of the mushroom cultivars, P. ostreatus 8 was the most resistant to all Trichoderma spp.. Chitinolytic mycotoxin released by Trichoderma spp. caused 52.7% damage to Pleurotus. Mycotoxins released by T. longibrachiatum caused the greatest damaged (78.6%) on P. eryngii.
Agaricales
;
Fungi*
;
Mycotoxins
;
Ostreidae*
;
Pleurotus*
;
Trichoderma
4.Investigation and research on fungal diversity of Platycladi Semen on Chinese market.
Zhen-Ying LIU ; Ling-Na WANG ; Yong-Qing ZHANG
China Journal of Chinese Materia Medica 2021;46(1):72-79
In the process of harvesting, production and processing, storage, and transportation, the traditional Chinese medicine Platycladi Semen is prone to mildew due to its own and environmental factors, which can nourish the production of toxic or pathogenic fungi, and even produce mycotoxins, which affects the safety of clinical medication. The 2020 edition of Chinese Pharmacopoeia limits the highest standard of aflatoxin content in Platycladi Semen. However, there are few studies on the fungal contamination of Platycladi Semen, and it is difficult to prevent and control it in a targeted manner. Therefore, based on the Illumina NovaSeq6000 platform, this article uses ITS sequence amplicon technology to analyze the distribution and diversity of fungi in 27 batches of commercially available Platycladi Semen in the Chinese market. A total of 10 phyla, 35 classes, 93 orders, 193 families, 336 genera, and 372 species of fungi were identified in China. Among them, Aspergillus, Alternaria spp. were dominant, 20 batches of samples were detected for A. flavus, 10 batches of samples were detected for A. nidulans, and all samples were detected for potential pathogenic fungi such as A. fumigatus and A. niger. According to diversity analysis, the diversity of the fungal communities in the samples from Gansu province was high, the samples in Shandong province contain the largest number of fungal species, and the samples in Guangxi province had the lo-west diversity and the least number of species. In most samples, pathogenic fungi such as A. fumigatus, A. niger, A. flavus, A. parasiticus were detected in varying degrees. This study systematically investigated the fungal contamination of Platycladi Semen from the markets in the last link of the its industrial chain, and clarified the distribution of Platycladi Semen fungi, especially toxin-producing fungi, and provided theoretical basis for the targeted prevention and control of fungal contamination in Platycladi Semen.
Aflatoxins
;
China
;
Fungi/genetics*
;
Humans
;
Mycobiome
;
Mycotoxins/analysis*
;
Semen/chemistry*
5.Microbe-Mediated Control of Mycotoxigenic Grain Fungi in Stored Rice with Focus on Aflatoxin Biodegradation and Biosynthesis Inhibition.
Mycobiology 2016;44(2):67-78
Rice contaminated with fungal species during storage is not only of poor quality and low economic value, but may also have harmful effects on human and animal health. The predominant fungal species isolated from rice grains during storage belong to the genera Aspergillus and Penicillium. Some of these fungal species produce mycotoxins; they are responsible for adverse health effects in humans and animals, particularly Aspergillus flavus, which produces the extremely carcinogenic aflatoxins. Not surprisingly, there have been numerous attempts to devise safety procedure for the control of such harmful fungi and production of mycotoxins, including aflatoxins. This review provides information about fungal and mycotoxin contamination of stored rice grains, and microbe-based (biological) strategies to control grain fungi and mycotoxins. The latter will include information regarding attempts undertaken for mycotoxin (especially aflatoxin) bio-detoxification and microbial interference with the aflatoxin-biosynthetic pathway in the toxin-producing fungi.
Aflatoxins*
;
Animals
;
Aspergillus
;
Aspergillus flavus
;
Fungi*
;
Humans
;
Mycotoxins
;
Penicillium
6.Populations of Fungi and Bacteria Associated with Samples of Stored Rice in Korea.
Ji Yeon OH ; Sam Nyu JEE ; Youngwoo NAM ; Hojoung LEE ; Mun Il RYOO ; Ki Deok KIM
Mycobiology 2007;35(1):36-38
Stored rice was collected from rice processing complexes of National Agricultural Cooperative Federation of 11 regions in Korea to evaluate the occurrence of fungi and bacteria and to identify the predominant fungi and bacteria to the genus levels. Most rice samples generally produced the higher levels of fungi and bacteria than white rice. The occurrence of fungi and bacteria varied in various locations of Korea. Among fungi observed, Aspergillus spp. and Penicillium spp. were dominant in the samples and Aspergillus spp. were observed more frequently than Penicillium spp. Predominant bacteria from rice and white rice samples tentatively belonged to the Genus Bacillus, Pectobacterium, Pantoea, and Microbacterium according to BIOLOG and FAME analyses. The results of this study showed that rice in Korea was contaminated in a relatively high level by two dominant storage fungi such as Aspergillus spp. and Penicillium spp. In addition, occurrence of mycotoxins in rice by the fungi could be possible and thus it is necessary to control the storage fungi.
Aspergillus
;
Bacillus
;
Bacteria*
;
Fungi*
;
Korea*
;
Mycotoxins
;
Pantoea
;
Pectobacterium
;
Penicillium
7.Isolation of Fusarium and identification of its toxins from tuberous root of Pseudostellaria heterophylla.
Qing-Song YUAN ; Tao DENG ; Jiu-Chun AN ; Lan-Ping GUO ; Shi-Hua ZHOU ; Chang-Gui YANG ; Bang-Xing HAN ; Chuan-Zhi KANG ; Xing-Peng LIU ; Tao ZHOU
China Journal of Chinese Materia Medica 2021;46(22):5792-5796
Fusarium is the major pathogen of root rot of Pseudostellaria heterophylla. This study aims to explain the possible distribution of Fusarium species and the contamination of its toxin-chemotypes in tuberous root of P. heterophylla. A total of 89 strains of fungi were isolated from the tuberous root of P. heterophylla. Among them, 29 strains were identified as Fusarium by ITS2 sequence, accounting for 32.5%. They were identified as five species of F. avenaceum, F. tricinctum, F. fujikuroi, F. oxysporum, and F. graminearum based on β-Tubulin and EF-1α genes. LC-MS/MS detected 18, 1, and 5 strains able to produce ZEN, DON, and T2, which accounted for 62.1%, 3.4%, and 17.2%, respectively. Strain JK3-3 can produce ZEN, DON, and T2, while strains BH1-4-1, BH6-5, and BH16-2 can produce ZEN and T2. PCR detected six key synthase genes of Tri1, Tri7, Tri8, Tri13, PKS14, and PKS13 in strain JK3-3, which synthesized three toxins of ZEN, DON, and T2. Four key synthase genes of Tri8, Tri13, PKS14, and PKS13 were detected in strains BH1-4-1, BH6-5, and BH16-2, which were responsible for the synthesis of ZEN and T2. The results showed that the key genes of toxin biosynthesis were highly correlated with the toxins produced by Fusarium, and the biosynthesis of toxin was strictly controlled by the genetic information of the strain. This study provides a data basis for the targeted prevention and control of exo-genous mycotoxins in P. heterophylla and a possibility for the development of PCR for rapid detection of toxin contamination.
Caryophyllaceae
;
Chromatography, Liquid
;
Fusarium/genetics*
;
Mycotoxins
;
Tandem Mass Spectrometry
8.Mould and mycotoxin contamination of medicinal materials.
China Journal of Chinese Materia Medica 2011;36(24):3397-3401
Medicinal materials may be contaminated with a broad variety of fungi, which are represented by Aspergillus spp, Penlicillium spp, Fusarium spp, Rhizopus spp, Mucor spp et al. This fact limits the utilization of medicinal materials, besides, medicinal materials may also be contaminated with mycotoxins produced by these fungi, and bring harm to human health. Several mycotoxins have been detected in medicinal materials, such as AFTs, OTA, FBs, et al. The contamination may originate from the conditions in which the medicinal plants are cultivated, stored and in the finished product manufacturing stages. Some methods have been used for detoxifcation and disinfection for medicinal materials, but they have limited effects. Taking into consideration the background situation, it is important for medicinal materials to be protected from contamination of fungi at every stage of production. The present study intends to give a review of contamination of medicinal materials by moulds and mycotoxins and discuss the factors influencing this situation, expecting to contribute to the knowledge for reducing the contamination.
Drug Contamination
;
prevention & control
;
Fungi
;
isolation & purification
;
Mycotoxins
;
analysis
9.Influence of Temperature and Water Activity on Deleterious Fungi and Mycotoxin Production during Grain Storage.
Mycobiology 2017;45(4):240-254
Cereal grains are the most important food source for humans. As the global population continues to grow exponentially, the need for the enhanced yield and minimal loss of agricultural crops, mainly cereal grains, is increasing. In general, harvested grains are stored for specific time periods to guarantee their continuous supply throughout the year. During storage, economic losses due to reduction in quality and quantity of grains can become very significant. Grain loss is usually the result of its deterioration due to fungal contamination that can occur from preharvest to postharvest stages. The deleterious fungi can be classified based on predominance at different stages of crop growth and harvest that are affected by environmental factors such as water activity (a(w)) and eco-physiological requirements. These fungi include species such as those belonging to the genera Aspergillus and Penicillium that can produce mycotoxins harmful to animals and humans. The grain type and condition, environment, and biological factors can also influence the occurrence and predominance of mycotoxigenic fungi in stored grains. The main environmental factors influencing grain fungi and mycotoxins are temperature and a(w). This review discusses the effects of temperature and a(w) on fungal growth and mycotoxin production in stored grains. The focus is on the occurrence and optimum and minimum growth requirements for grain fungi and mycotoxin production. The environmental influence on aflatoxin production and hypothesized mechanisms of its molecular suppression in response to environmental changes are also discussed. In addition, the use of controlled or modified atmosphere as an environmentally safe alternative to harmful agricultural chemicals is discussed and recommended future research issues are highlighted.
Aflatoxins
;
Agrochemicals
;
Animals
;
Aspergillus
;
Atmosphere
;
Biological Factors
;
Crops, Agricultural
;
Edible Grain
;
Fungi*
;
Humans
;
Mycotoxins
;
Penicillium
;
Water*
10.Timing of Fusarium Head Blight Infection in Rice by Heading Stage.
Yangseon KIM ; In Jeong KANG ; Dong Bum SHIN ; Jae Hwan ROH ; Sunggi HEU ; Hyeong Kwon SHIM
Mycobiology 2018;46(3):283-286
Fusarium graminearum causes the devastating plant disease Fusarium head blight and produces mycotoxins on small cultivated grains. To investigate the timeframe of F. graminearum infection during rice cultivation, a spore suspension of F. graminearum was applied to the rice cultivars Dongjin 1 and Nampyeongbyeo before and after the heading stage. The disease incidence rate was the highest (50%) directly after heading, when the greatest number of flowers were present, while only 10% of the rice infected 30 days after heading showed symptoms. To understand the mechanism of infection, an F. graminearum strain expressing green fluorescent protein (GFP) was inoculated, and the resulting infections were visually examined. Spores were found in all areas between the glume and inner seed, with the largest amount of GFP detected in the aleurone layer. When the inner part of the rice seed was infected, the pathogen was mainly observed in the embryo. These results suggest that F. graminearum migrates from the anthers to the ovaries and into the seeds during the flowering stage of rice. This study will contribute to uncovering the infection process of this pathogen in rice.
Embryonic Structures
;
Female
;
Flowers
;
Fusarium*
;
Head*
;
Incidence
;
Mycotoxins
;
Ovary
;
Plant Diseases
;
Spores