Lysohexaenetides A and B, linear lipopeptides from Lysobacter sp. DSM 3655 identified by heterologous expression in Streptomyces / 中国天然药物

Lysobacter harbors a plethora of cryptic biosynthetic gene clusters (BGCs), albeit only a limited number have been analyzed to date. In this study, we described the activation of a cryptic polyketide synthase (PKS)/nonribosomal peptide synthetase (NRPS) gene cluster (lsh) in Lysobacter sp. DSM 3655 through promoter engineering and heterologous expression in Streptomyces sp. S001. As a result of this methodology, we were able to isolate two novel linear lipopeptides, lysohexaenetides A (1) and B (2), from the recombinant strain S001-lsh. Furthermore, we proposed the biosynthetic pathway for lysohexaenetides and identified LshA as another example of entirely iterative bacterial PKSs. This study highlights the potential of heterologous expression systems in uncovering cryptic biosynthetic pathways in Lysobacter genomes, particularly in the absence of genetic manipulation tools.

Biosíntesis inducida de fengicina y surfactina en una cepa de Bacillus amyloliquefaciens con actividad oomiceticida sobre zoosporas de Phytophthora capsica / Induced biosynthesis of fengycin and surfactin in a strain of Bacillus amyloliquefaciens with oomyceticidal activity on zoospores of Phytophthora capsici

Resumen La aplicación de metabolitos antimicrobianos biosintetizados por especies de Bacillus es una alternativa potencial para controlar Phytophthora capsici (P. capsici) en hortalizas y podría evitar el uso de productos químicos con acción oomiceticida. El objetivo de este estudio fue evaluar el impacto de la adición al medio de cultivo de distintos agentes (ácido glutámico, hierro, celulosa, quitina y células inactivas de Colletotrichum spp.) sobre la biosíntesis de lipopéptidos en Bacillus amyloliquefaciens KX953161.1 y examinar la capacidad oomiceticida de dichos compuestos in vitro sobre las zoosporas de P. capsici. Los lipopéptidos identificados y cuantificados por cromatografía en capa fina de alta resolución (HPTLC) en los extractos crudos fueron fengicina y surfactina. El cultivo bacteriano adicionado con células inactivas de Colletotrichum spp. demostró la mayor biosíntesis de lipopéptidos: 1.847,02 ±11,8 pg/mL de fengicina y 2.563,45 ± 18,4 pg/mL de surfactina. Los tratamientos con menor producción de estos lipopéptidos fueron aquellos a los que se añadió hierro (608,05 ± 22,6 pg/mL de fengicina y 903,74 ±22,1 pg/mL de surfactina) o celulosa (563,31 ±11,9 y 936,96 ±41,1 pg/mL, igual orden). El extracto con los lipopéptidos presentó una inhibición del 100% en la germinación de zoosporas de P. capsici, se observó enquistamiento, malformaciones en el tubo germinal y degradación celular. Se concluye que los lipopéptidos producidos por B. amyloliquefaciens KX953161.1 podrían contribuir al control de P. capsici, sin embargo, se requieren más estudios a fin de elucidar el modo de acción biológica de estos compuestos y optimizar el perfil de producción y el rendimiento.

Abstract A potential alternative to the use of chemical products with oomyceticidal action for the control of Phytophthora capsici in vegetables is the use of antimicrobial metabolites, biosynthesized in Bacillus species. The objective of this study was to induce the biosynthesis of lipopeptides in Bacillus amyloliquefaciens KX953161.1 by using glutamic acid, iron, cellulose, chitin, or inactive Colletotrichum spp. cells. The in vitro oomyceticidal effect of the bacterial lipopeptides on zoospores of Phytophthora capsici was evaluated. The lipopeptides identified and quantified in the crude extracts by high performance thin layer chromatography (HPTLC) were fengycin and surfactin. The bacterial culture with inactive fungal cells yielded the greatest biosynthesis of lipopeptides, at 1847.02± 11.8 and 2563.45± 18.4 pg/ml of fengycin and surfactin, respectively and the treatments that obtained lower production of these lipopepti-des, were those to which iron and cellulose were added with 608.05 ± 22.6 and 903.74± 22.1; 563.31± 11.9 and 936.96± 41.1 pg/ml for fengicin and surfactin, respectively. The lipopeptide extracted showed 100% germination inhibition on zoospores of P. capsici, revealing encystment, malformations in the germ tube and cellular degradation. Lipopeptides have the potential to control P. capsici; however, the biosynthesis of these lipopeptides requires further study to determine their biological mode of action and optimize lipopeptide performance and profile.

Evolution of modern age drug discovery of lipopeptides and computer-aided drug discovery in India

The endeavor has been attempted to present a review on the evolution of modern age drug discovery in India. The contribution of next generation therapeutics options microbial metabolites and the computational drug discovery aspects to the global market from India have been represented. Microbial metabolites such as lipopeptides and peptide therapeutics are gaining worldwide importance due to their multiple applications as broad-spectrum antimicrobial, antiviral, anticancer properties etc. Due to the surge of microbial resistance, tumor resistance, and ongoing pandemic due to constantly mutating corona virus, there is a need to develop next-generation therapeutics options from natural origin, less toxic to the environment, and have higher specificity towards target. Small molecule therapeutics are certainly less specific towards cancer targets hence the cytotoxicity is a major issue in cancer treatment while drug resistance due to the mutations are coming as challenges every day for drug discovery researchers. Microbial lipopeptide reserves a sweet spot in between the small molecule inhibitors and peptide therapeutics because of their amphiphilic compounds consist of a fatty acid side chain and a cyclic peptide moiety of hydrophilic nature. The computational drug discovery approach accelerates the drug discovery process due to the advancement in supercomputer facilities provided by various funding agencies such as the Department of Biotechnology (DBT) and the Department of Science and Technology (DST) in India. The current review article is focusing light on the research contribution of Indian Scientists and Govt. of India in the field of lipopeptide-based research and applications of Computer-aided drug discovery.

Advances in several important antimicrobial lipopeptids from Bacillus spp / 生物工程学报

Bacillus spp. are probiotics and can secrete a variety of natural antimicrobiol active substances, of which lipopeptides are an important class. Up to now, about 90 lipopeptides have been identified, and most of them are cyclic lipopeptides. surfactin, iturin, fengycin, bacillomycin and polymyxins are widely studied, and the first three have huge potential for application due to their properties of surfactants and anti-fungal, anti-bacterial, anti-viral, anti-tumor and anti-inflammatory functions. In this paper, the research progress in the structure, function, synthesis regulation, separation, purification and production of surfactin, iturin and fengycin was reviewed. Synthetic biology is a vital means to increase the yield of lipopeptides, and in the future, lipopeptides can be used in crop cultivation, animal farming, food, medicine and petroleum industries as well as environmental protection. Future research should be strengthened on the discovery of new lipopeptides, synthesis of high-activity lipopeptides, economical production of lipopeptides on a large scale and their safety evaluation.

Successful treatment of fungal endophthalmitis using intravitreal caspofungin / O primeiro relato de caspofungina intravítrea no tratamento de endoftalmite fúngica

ABSTRACT Fungal endophthalmitis is a rare condition often associated with poor prognosis. We present a case of postoperative acute fungal endophthalmitis caused by the yeast-like fungus Stephanoascus ciferrii (Candida ciferrii). The fungus was resistant to fluconazole, voriconazole, and amphotericin B but susceptible to caspofungin. Because the degree of vitreal penetration of caspofungin after its intravenous administration is unclear, we performed multiple intravitreal injections, first with 50 µg/0.1 ml and then with 250 µg/0.1 ml caspofungin. Despite the recurrence of symptoms, intravitreal injection of caspofungin finally abolished the inflammation and achieved ambulatory vision that persisted until 1 year of follow-up. To our knowledge, this is the first report of S. ciferrii endophthalmitis and its successful treatment with intravitreal caspofungin.

RESUMO Endoftalmite fúngica é uma ocorrência rara, muitas vezes associada com mau prog nóstico. Apresentamos um caso de endoftalmite fúngica aguda pós-operatória causada por fungo de levedura incomum, Stephanoascus ciferrii (Candida ciferrii). O fungo foi resistente ao fluconazol, ao voriconazol e à anfotericina B e susceptível à caspofun gina. Dado que a penetração vítrea da caspofungina após administração intravenosa não é clara, optou-se por realizar múltiplas injecções intravítreas, primeiro de 50 µg e depois de 250 µg de caspofungina, e finalmente obteve-se a resolução da inflamação e a visão recuperada foi mantida por pelo menos um ano após o ocorrido. No nosso conhecimento, este é o primeiro relato de endoftalmite por Stephanoascus ciferrii e o primeiro relato de endoftalmite fúngica tratada com sucesso com caspofungina intravítrea.

Antifungical Activity of Autochthonous Bacillus subtilis Isolated from Prosopis juliflora against Phytopathogenic Fungi

The ability of Bacillus subtilis, strain ALICA to produce three mycolytic enzymes (chitinase, β-1,3-glucanase, and protease), was carried out by the chemical standard methods. Bacillus subtilis ALICA was screened based on their antifungal activity in dual plate assay and cell-free culture filtrate (25%) against five different phytopathogenic fungi Alternaria alternata, Macrophomina sp., Colletotrichum gloeosporioides, Botrytis cinerea, and Sclerotium rolfesii. The B. subtilis ALICA detected positive for chitinase, β-1,3-glucanase and protease enzymes. Fungal growth inhibition by both strain ALICA and its cell-free culture filtrate ranged from 51.36% to 86.3% and 38.43% to 68.6%, respectively. Moreover, hyphal morphological changes like damage, broken, swelling, distortions abnormal morphology were observed. Genes expression of protease, β-1,3-glucanase, and lipopeptides (subtilosin and subtilisin) were confirmed their presence in the supernatant of strain ALICA. Our findings indicated that strain ALICA provided a broad spectrum of antifungal activities against various phytopathogenic fungi and may be a potential effective alternative to chemical fungicides.

Effect of the administration time of hs6101 on hematopoietic recovery in ICR mice injured by cyclophosphamide / 解放军医学杂志

Objective To explore the effect of the administration time of HS6101 on hematopoietic recovery in ICR mice injured by cyclophosphamide (CTX). Methods One hundred and three male ICR mice were divided into 4 groups: CTX control, HS6101 prevention, HS6101 treatment, and HS6101 prevention+treatment groups. CTX was intraperitoneally injected into the ICR mice at a dose of 100mg/(kg.d) for three consecutive days to establish a chemotherapeutics-injured model. HS6101 at a dose of 27μg/mouse in 0.2ml was subcutaneously injected into the mice 1h before the first administration of CTX in HS6101-preventiongroup, 1h after the last administration of CTX in HS6101 treatment group, and both at 1h before the first administration and 1h after the last administration of CTX in HS6101 prevention + treatment group. Physiological saline was subcutaneously injected into the mice in CTX control group (0.2ml/mouse). 10μl peripheral blood was collected from the caudal vein for WBC, neutrophil lymphocyte, RBC and platelet counts on day -1, 3, 5, 7, 9, 11, 13, 15, 17 with the MEK-7222K cell analyzer, and the cell count was compared between HS6101 treatment mice and CTX control mice. Another 30 male ICR mice were used for bone marrow colony forming unit (CFU) assay and bone marrow histopathological examination, and they were assigned into normal control, CTX control, HS6101 prevention, HS6101treatment and HS6101 prevention + treatment groups (each n=6). On the day 4 and day 9 after CTX injection, mice were sacrificed and bone marrow cells were collected from the left femur for mononuclear cell (MNC) isolation. 1×104 MNCs were planted in 1.0ml mouse CFU culture medium M3434 and cultured in incubator with the temperature of 37℃, and 5% CO2 for 7 days. After that, granulocyte macrophage-colony-forming unit (GM-CFU), megakaryocyte colony forming unit (MK-CFU), mixture-colony-forming unit (Mix-CFU), burst-forming unit-erythroid (BFU-E) and colony-forming unit-erythroid (CFU-E) were counted. Then the right femur was taken for histopathology examination. Results After CTX injection, counts of WBC, neutrophils, lymphocytes, RBC and platelets of all the mice decreased rapidly. However, the nadirs of WBC, neutrophils and lymphocytes counts in HS6101 prevention group were higher than those in CTX control group, and the counts on day 3 were higher than those in HS6101 treatment group and HS6101 prevention+ treatment group. On day 3, RBC count in HS6101 prevention group was the highest. It was higher on day 5 and day 7 than that of mice in CTX group. In addition, the platelet count in HS6101 prevention group was also the highest on day 3, although that in HS6101 treatment group and 6101 prevention + treatment group was lower than CTX control group. Bone marrow colony forming unit assay showed that the counts of GM-CFU, MK-CFU, BFU-E and CFU-E in all the HS6101 treatment mice were significantly higher than those in CTX control mice. On day 4, histopathological examination of bone marrow from HS6101-treated mice displayed more intact architecture compared with CTX control mice. Three of eighteen (3/18) mice died in HS6101 treatment group, and nine of eighteen (9/18) died in HS6101 prevention + treatment group, suggesting that HS6101 should not be administered after CTX injection. Conclusion Administration of HS6101 at 1h before giving CTX could significantly promote hematopoietic recovery in ICR mice injured by CTX.

Bacillus sp. BS061 Suppresses Gray Mold and Powdery Mildew through the Secretion of Different Bioactive Substances

A Bacillus sp. BS061 significantly reduced disease incidence of gray mold and powdery mildew. To identify the active principle, the culture filtrate was partitioned between butanol and water. The antifungal activity against B. cinerea was evident in the butanol-soluble portion, and active substances were identified as cyclic lipopeptides, iturin A series, by nuclear magnetic resonance spectrometry (NMR) and mass analysis. Interestingly, antifungal activity against powdery mildew was observed in the water-soluble portion, suggesting that cyclic lipopeptides have no responsibility to suppress powdery mildew. This finding reveals that biocontrol agents of Bacillus origin suppress gray mold and powdery mildew through the secretion of different bioactive substances.

Antimicrobial activity of surfactants produced by Bacillus subtilis R14 against multidrug-resistant bacteria

Lipopeptides represent a class of microbial surfactants with increasing scientific, therapeutic and biotechnological interests. The genus Bacillus is a producer of these active compounds, and among them B. subtilis produces surfactin, the most potent biosurfactant known. These compounds can act as antibiotics, antivirals, antitumorals, immunomodulators and enzyme inhibitors. In this work, the antimicrobial activity of biosurfactants obtained by cultivation of B. subtilis R14 was investigated against multidrug-resistant bacteria. During cultivation in defined medium, the surface tension of the medium was reduced from 54 mN/m in the beginning of the microbial growth to 30 mN/m after 20 hours. A crude surfactant concentration of 2.0 g/L was obtained after 40 hours of cultivation. A preliminary characterization suggested that two surfactants were produced. The evaluation of the antimicrobial activity of these compounds was carried out against 29 bacteria. Enterococcus faecalis (11 strains), Staphylococcus aureus (6 strains) and Pseudomonas aeruginosa (7 strains) and Escherichia coli CI 18 (1 strain) displayed a profile of well defined drug resistance. All strains were sensitive to the surfactants, in particular Enterococcus faecalis. The results demonstrated that lipopeptides have a broad spectrum of action, including antimicrobial activity against microorganisms with multidrug-resistant profiles.

Os lipopeptídeos representam uma classe de surfactantes microbiológicos com crescente interesse científico, terapêutico e biotecnológico. O gênero Bacillus é um dos maiores produtores destes compostos ativos. Dentre as espécies produtoras de biossurfactante, B. subtilis produz surfactina um dos mais conhecidos. Estes compostos atuam como antibióticos, antivirais, agente antitumorais, imunomoduladores e inibidores enzimáticos. O objetivo deste trabalho foi determinar a atividade antimicrobiana de biossurfactantes, obtidos pelo cultivo de B. subtilis R14, frente a bactérias multidroga-resistentes. Durante o cultivo em meio quimicamente definido, a tensão superficial do meio foi reduzida de 54 mN/m no início do crescimento microbiano para 30 mN/m depois de 20 h. Uma concentração de surfactante bruto de 2 g/L foi obtida depois de 40h de cultivo. Uma caracterização preliminar sugeriu que dois surfactantes foram produzidos. A avaliação antimicrobiana destes compostos foi realizada frente a vinte e nove bactérias. O perfil de multidroga-resistência foi previamente definido para Enterococcus faecalis (11 cepas) Staphylococcus aureus (6 cepas), Pseudomonas aeruginosa (7 cepas) e Escherichia coli IC18. Todas as cepas foram sensíveis aos surfactantes, em particular Enterococcus faecalis. Os resultados demonstraram que os lipopeptídios têm um amplo espectro de ação, incluindo microrganismos multidroga-resistentes.

Antagonistic Properties of Lipopeptides and Volatiles Produced by Bacillus subtilis JA / 微生物学通报

Lipopeptides produced by Bacillus subtilis JA antagonized a broad spectrum of fungal pathogens. Crude lipopeptides were extracted with methanol from the precipitate which was obtained by adding 6 mol/L HCl to the cell-free culture broth.The crude extract was run on Diamonsil C_(18)column(5?m,250 mm?4.6 mm) in reverse phase HPLC system to purify the lipopeptides.Inhibitory ability and IC_(50)values of lipopeptides towards various microorganisms were determined by agar diffusion method.The results showed lipopeptides exhibited strong inhibitory activity against some important plant pathogenic fungi,including R.solani and F.oxysporum.The ability of B.subtilis JA to antagonize against the growth of the post-harvest pathogen -B,cinerea was tested in vitro.Spore germination of B.cinerea was strongly inhibited in the presence of JA cell suspension.Furthermore,B.subtilis JA can produce antifungal volatiles which strongly inhibited the spore germination and mycelial growth of B.cinerea.As a biocontrol agent,the synergic effect of lipopeptides and volatiles may play a major role in controlling the pathogens by B.subtilis JA.