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Transformation of Natural Products by Marine-Derived Microorganisms
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Thayane Melo de Queiroz, André Luiz Meleiro Porto
In another study, Li et al. (2007) described the biotransformation of the sesquiterpene cyclonerodiol by the ascomycete Penicillium sp. and the actinomycete Streptomyces sp., isolated from the alga Sargassum thunbergii (Korea) and from the sea plant Zostera marina (Korea), respectively. The microbial transformation of cyclonerodiol was performed in a culture medium containing soytone (0.1%), soluble starch (1.0%), and seawater under conditions of 29°C and 130 rpm for 72 hours. The biotransformation experiments employing the fungus Penicillium sp. allowed for the isolation of the metabolite cyclonerodiol mannopyranoside (12.0 mg). The actinomycete Streptomyces sp. favoured the formation of compounds (10Z)-cyclonerotriol (3.4 mg) and (10E)-cyclonerotriol (7.6 mg; Figure 5.2). These compounds were characterised by nuclear magnetic resonance (NMR), high resolution mass spectrometry (HRMS), and Fourier-transform infrared (FTIR).
Current and Future Perspectives of Marine Drugs for Cancer Disorders: A Critical Review
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Bhaskaran Mahendran, Thirumalaraju Vaishnavi, Vishakante Gowda, Johurul Islam, Narahari Rishitha, Arunachalam Muthuraman, Rajavel Varatharajan
Actinomycetes are mainly developed from the soil source. The sediment of marine lands especially in Laguna de Terminos, Gulf of Mexico has potent anti-cancer molecules, i.e., gutingimycin. The high polar compound of gutingimycin is trioxacarcin derivatives and it isolated from Streptomyces species. Further, this species also has large yields of trioxacarcins D &F molecules. These compounds are also documented to shown potential antibiotic and anticancer actions via inhibition of cancer cell proteasome function (Tan et al., 2015). In addition to that, the newer marine compound, i.e., thiocoraline (depsipeptide) has anticancer action via inhibits RNA synthesis process of cancer cells. From Micromonospora marina it was isolated and it is located in Mozambique Strait. It selectively acts on colon and lung cancer cell lines and moreover in melanoma (Newman and Cragg, 2004). Moreover, it exerts the anti-proliferative action on defective p53 associated colon cancer cell lines (Efferth et al., 2001). Hence, thiocoraline claimed as an anticancer agent for colon cancer. However, the more extensive investigation is required to use the marine actinomycetes derived molecules in a human being.
Tropical Colorectal Surgery
Published in Peter Sagar, Andrew G. Hill, Charles H. Knowles, Stefan Post, Willem A. Bemelman, Patricia L. Roberts, Susan Galandiuk, John R.T. Monson, Michael R.B. Keighley, Norman S. Williams, Keighley & Williams’ Surgery of the Anus, Rectum and Colon, 2019
Meheshinder Singh, Kemal I. Deen
Actinomycetes are usually avirulent microrganisms, and they seldom cause disease. They become pathogenic through invasion or a break in the integrity of mucous membranes and in the presence of devitalised tissue. Once infection is established, the host mounts an inflammatory response with granulation and suppuration ultimately resulting in the formation of abscesses, fistula and sinus tracts86 that may discharge sulphur granules. Factors that predispose to abdominal actinomycosis include abdominal operations, abdominal trauma or a perforated viscus. Abdominal actinomycosis is most frequently seen at the ileocaecal region where it typically presents as a slowly growing tumour. The diagnosis is usually established post-operatively following an exploratory laparotomy for a suspected malignancy.
Toxicity of the herbicides used on herbicide-tolerant crops, and societal consequences of their use in France
Published in Drug and Chemical Toxicology, 2022
ALS-inhibiting enzymes are contributing among several other causes and chemicals to the loss of biodiversity. The representative tree species of the Brazilian forest Dipteryx alata, ranked by the International Union for Conservation of Nature among the vulnerable species, has been shown to be sensitive to recommended dose of the SUL nicosulfuron, with the onset of an oxidative stress and the alteration of the photosynthetic potential (Silva et al. 2020). The ALS-inhibiting herbicide bispyribac at the recommended dose of 35 g/ha triggered a decrease of the soil microbial population and of microbial diversity, and a decrease of microbial enzyme activities such as dehydrogenases and urease (Kumar et al. 2020). In soils from fields treated with 30 g of the SUL chlorimuron-ethyl/ha for 5 and 10 years, in which soybean had been cropped continuously, the residual herbicide concentrations were 3.4 and 8.5 μg/kg, and the soil microbial population presented a 33 and 51% decrease, with a shift of the soil bacterial and fungal community structure. In particular, after 10 years of treatment, the actinomycete titer decreased 7.5-fold whereas the fungal titer increased 2.5-fold (Zhang et al. 2011).
Punctal dilatation and non-incisional canalicular curettage in the management of infectious canaliculitis
Published in Orbit, 2020
Nandini Bothra, Abhimanyu Sharma, Oshin Bansal, Mohammad Javed Ali
A total of 53 canaliculi of 47 eyes of 46 consecutive patients with a mean age of 59.34 years (range: 19–87 years), were evaluated. Female preponderance was noted with a male: female ratio of 19:28. Left eyes were more affected (64%, n = 30) than the right eyes (36%, n = 17), the reasons for which could only be speculated. Lower canaliculus was most commonly involved (68%, n = 32). Six eyes (13%) showed involvement of both upper and lower canaliculus. Presenting symptoms included discharge (81%), swelling along the medial part of the eyelids (64%), watering (55%), redness (51%) and pain (39%). Of the 47 eyes, 14 eyes (30%) underwent a repeat curettage to achieve a complete resolution and one eye underwent the procedure thrice. The common micro-organisms isolated were the Streptococci species (28%, n = 13), Staphylococci (11%, n = 5), and Actinomycetes (11%, n = 5). However, all cases with actinomycetes isolation also had a mixed infection. Other organisms were isolated in the remaining cases. At a mean follow-up of 6.8 months (6 weeks–12 months), resolution of canaliculitis was achieved in all patients; however, two patients had persistent epiphora post-resolution. No intraoperative or post-operative complications were documented. None of the patients were noted to have any canalicular injury or canalicular obstruction at the final follow-up.
Metabolomics in antimicrobial drug discovery
Published in Expert Opinion on Drug Discovery, 2022
In the beginning and during the golden age of the antibiotic era, the antimicrobial drug discovery programs were mainly focused on the investigation of soil bacteria, which produce numerous secondary metabolites with antimicrobial activity [42–44]. Technically, this approach was accomplished by monitoring the inhibition by a test strain, which is a suspected producer of antimicrobial(s), of an indicator strain/pathogen. This activity-based approach produced many classes of antimicrobials, but the last novel class, lincosamides, was discovered more than 50 years ago [43]. Presently, the prevailing majority of antimicrobial drugs in the late clinical development belong to the already existing antimicrobial classes, with only a few narrow spectrum compounds directed toward novel bacterial targets [45]. Strategies for discovery of new antimicrobials should be indisputably extended beyond the well-known soil Actinomycetes, and other ecological niches and taxonomic groups have to be explored. At the same time, we have to admit that the full potential of soil microbiota could still be under-explored due to the reliance on cultivable microbiota and on traditional activity-based screening methods, which still dominate the strategies of antimicrobial drug discovery. The use of advanced cultivation techniques such as iChip, which emulates environmental conditions, may help to improve the recovery of difficult-to-cultivate bacteria, and increase the throughput [46]. Also, metagenomic approach could help to recover and express DNA from uncultivated microbiota, which may contain gene clusters encoding for new antimicrobials [47]. Heterologous expression therefore may help to reveal antimicrobial potentials of silent biosynthetic gene clusters.