An effective biosurfactant producer and extremophiles bacteria, Bacillus cereus KH1, was isolated from textile effluent and the biosurfactant was produced using molasses as the sole carbon source. Growth parameters such as pH, temperature, salinity and concentration of molasses were optimised for decolourising the textile effluent with 24-h incubation. The biosurfactant property of B. cereus KH1 was evaluated based on haemolytic activity, oil displacement technique, drop-collapsing test and emulsification index. The results of the produced biosurfactant showed a positive reaction in haemolytic activity, oil displacement technique, drop-collapsing test and exhibiting a 67% emulsification index. The cell-free broth was stable in 40 °C pH 7, 7% salinity and 7% molasses. Thin-Layer Chromatography and Fourier Transform Infrared Spectroscopy analysis revealed that the biosurfactant was a lipopeptide with a yield 2.98 g L-1. These findings proved the synergistic action of B. cereus KH1 with lipopeptide biosurfactant may accelerated the decolourisation efficiency to 87%.
The spread of drug-resistant bacteria has imparted a sense of urgency in the search for new antibiotics. In an effort to develop a new generation of antibacterial agents, we have designed de novo charged lipopeptides inspired by natural antimicrobial peptides. These short lipopeptides are composed of cationic lysine and hydrophobic lipoamino acids that replicate the amphiphilic properties of natural antimicrobial peptides. The resultant lipopeptides were found to self-assemble into nanoparticles. Some were effective against a variety of Gram-positive bacteria, including strains resistant to methicillin, daptomycin and/or vancomycin. The lipopeptides were not toxic to human kidney and liver cell lines and were highly resistant to tryptic degradation. Transmission electron microscopy analysis of bacteria cells treated with lipopeptide showed membrane-damage and lysis with extrusion of cytosolic contents. With such properties in mind, these lipopeptides have the potential to be developed as new antibacterial agents against drug-resistant Gram-positive bacteria.
Penaeus vannamei is one of the most economically vital shrimp globally, but infectious diseases have hampered its proper production and supply. As antibiotics pose a huge threat to the environment and humankind, it is essential to seek an alternative strategy to overcome infection and ensure proper culture and production. The present study investigates the effect of an anti-infective biosurfactant derivative lipopeptide MSA31 produced by a marine bacterium on the growth performance, disease resistance, and the gut microbiome of P. vannamei when challenged with pathogenic Vibrio parahaemolyticus SF14. The shrimp were fed with a commercial and lipopeptide formulated diet for 60 days and the growth performance was analyzed. The lipopeptide fed shrimp group showed enhanced growth performance and specific growth rate with improved weight gain than the control group. The challenge experiment showed that the survival rate was significant in the lipopeptide fed group compared to the control group. The results revealed 100% mortality in the control group at the end of 12 h of challenge, while 50% of the lipopeptide diet-fed group survived 24 h, which indicates the enhanced disease resistance in shrimp fed with a lipopeptide diet. The test group also showed higher levels of digestive and immune enzymes, which suggests that the lipopeptide diet could positively modulate the digestive and immune activity of the shrimp. The gut microbiome profiling by Illumina high-throughput sequencing revealed that the most abundant genera in the lipopeptide diet-fed group were Adhaeribacter, Acidothermus, Brevibacillus, Candidatus, Mycobacterium, Rodopila, and Streptomyces, while opportunistic pathogens such as Streptococcus, Escherichia, Klebsiella, Neisseria, Rhizobium, and Salmonella were abundant in the control diet-fed shrimp. Also, lipopeptide diet-fed shrimp were found to have a high abundance of ammonia and nitrogen oxidizing bacteria, which are essential pollutant degraders. Therefore, the study reveals that the dietary supplementation of lipopeptide in shrimp aquaculture could positively modulate the gut microbiome and enhance the shrimp's overall health and immunity in an eco-friendly manner.
Micafungin was shown to be as efficacious as caspofungin in treating patients with candidaemia and invasive candidiasis (IC). However, it remains unknown if micafungin or caspofungin is a cost-effective definitive therapy for candidaemia and IC in Turkey. The present study aimed to determine the economic impact of using micafungin versus caspofungin for treatment of candidaemia and IC in the Turkish setting. A decision analytic model was constructed and was populated with data (i.e. transition probabilities, duration of initial antifungal treatment, reasons for treatment failure, percentage of patients who stepped down to oral fluconazole, and duration on oral fluconazole) obtained from a published randomised clinical trial. Cost inputs were derived from the latest Turkish resources while data that were not readily available in the literature were estimated by expert panels. One-way sensitivity analyses, threshold analyses, scenario analyses and probabilistic sensitivity analyses were conducted. Caspofungin (€2693) incurred a lower total cost than micafungin (€4422), with a net cost saving of €1729 per treated patient. Drug acquisition cost was the main cost driver for both study arms. The model outcome was robust over wide variations (of ±100.0% from the base case value) for all input parameters except for micafungin drug cost and the duration of initial treatment with micafungin. Caspofungin appears to be a cost-saving option in treating candidaemia and IC from the Turkish hospital perspective.
Matched MeSH terms: Lipopeptides/economics*; Lipopeptides/therapeutic use
The present study focused on lipopeptide biosurfactant production by Streptomyces sp. PBD-410L in batch and fed-batch fermentation in a 3-L stirred-tank reactor (STR) using palm oil as a sole carbon source. In batch cultivation, the impact of bioprocessing parameters, namely aeration rate and agitation speed, was studied to improve biomass growth and lipopeptide biosurfactant production. The maximum oil spreading technique (OST) result (45 mm) which corresponds to 3.74 g/L of biosurfactant produced, was attained when the culture was agitated at 200 rpm and aeration rate of 0.5 vvm. The best aeration rate and agitation speed obtained from the batch cultivation was adopted in the fed-batch cultivation using DO-stat feeding strategy to further improve the lipopeptide biosurfactant production. The lipopeptide biosurfactant production was enhanced from 3.74 to 5.32 g/L via fed-batch fermentation mode at an initial feed rate of 0.6 mL/h compared to that in batch cultivation. This is the first report on the employment of fed-batch cultivation on the production of biosurfactant by genus Streptomyces.
Peptides are of great interest to be used as vaccine antigens due to their safety, ease of manufacturing and specificity in generating immune response. There have been massive discoveries of peptide antigens over the past decade. However, peptides alone are poorly immunogenic, which demand co-administration with strong adjuvant to enhance their immunogenicity. Recently, fibril-forming peptides such as Q11 and lipoamino acid-based carrier have been identified to induce substantial immune responses when covalently linked to peptide epitope. In this study, we have incorporated either Q11 or lipoamino acids to a peptide epitope (J14) derived from M protein of group A streptococcus to develop self-adjuvanting vaccines. J14, Q11 and lipoamino acids were also conjugated together in a single vaccine construct in an attempt to evaluate the synergy effect of combining multiple adjuvants. Physicochemical characterization demonstrated that the vaccine constructs folded differently and self-assembled into nanoparticles. Significantly, only vaccine constructs containing double copies of lipoamino acids (regardless in conjugation with Q11 or not) were capable to induce significant dendritic cells uptake and subsequent J14-specific antibody responses in non-sizes dependent manners. Q11 had minimal impact in enhancing the immunogenicity of J14 even when it was used in combination with lipoamino acids. These findings highlight the impact of lipoamino acids moiety as a promising immunostimulant carrier and its number of attachment to peptide epitope was found to have a profound effect on the vaccine immunogenicity.
Candida wangnamkhiaoensis is a species clustered under the Hyphopichia clade has not ever been isolated from any clinical specimens. To the best of our knowledge, this is the first report of C. wangnamkhiaoensis associated with fungaemia in immunocompromised paediatric patient. The isolate was assigned a strain name as UZ1679/14, in which the identification was confirmed by a polymerase chain reaction-sequencing of the internal transcribed spacer (ITS) and large subunit (LSU) regions of the rRNA gene. Antifungal susceptibility pattern showed that the isolate was sensitive to anidulafungin, caspofungin, fluconazole and voriconazole. The patient clinically improved after the antifungal treatment with caspofungin.
Matched MeSH terms: Lipopeptides/pharmacology; Lipopeptides/therapeutic use
Rhodococci are renowned for their great metabolic repertoire partly because of their numerous putative pathways for large number of specialized metabolites such as biosurfactant. Screening and genome-based assessment for the capacity to produce surface-active molecules was conducted on Rhodococcus sp. ADL36, a diesel-degrading Antarctic bacterium. The strain showed a positive bacterial adhesion to hydrocarbon (BATH) assay, drop collapse test, oil displacement activity, microplate assay, maximal emulsification index at 45% and ability to reduce water surface tension to < 30 mN/m. The evaluation of the cell-free supernatant demonstrated its high stability across the temperature, pH and salinity gradient although no correlation was found between the surface and emulsification activity. Based on the positive relationship between the assessment of macromolecules content and infrared analysis, the extracted biosurfactant synthesized was classified as a lipopeptide. Prediction of the secondary metabolites in the non-ribosomal peptide synthetase (NRPS) clusters suggested the likelihood of the surface-active lipopeptide production in the strain's genomic data. This is the third report of surface-active lipopeptide producers from this phylotype and the first from the polar region. The lipopeptide synthesized by ADL36 has the prospect to be an Antarctic remediation tool while furnishing a distinctive natural product for biotechnological application and research.
Biosurfactants are microbially produced surface active agents that offer better biodegradability and lower toxicity than chemically synthesized surfactants because of their biogenetic origin. One of the most surface-active biosurfactants known is surfactin, a cyclic lipopeptide produced by various strains of Bacillus subtilis. In this study, the cleaning potential of surfactin on ultrafiltration (UF) membranes fouled with BSA was studied using centrifugal UF devices of 50 kDa and 100 kDa MWCO polyethersulfone (PES) membranes. Mechanisms of bovine serum albumin (BSA) displacement by surfactin on fouled UF membranes were studied using dynamic light scattering (DLS) technique and surface tension measurements. Hydrodynamic diameter and surface tension measurements of BSA-surfactin mixtures showed that the surfactin was efficient in displacing BSA fouled on UF membranes due to strong electrostatic repulsive interactions involved at pH8.5. This study demonstrated that surfactin can be used to effectively clean fouled UF membranes.
For the past several decades, there has been little improvement in the morbidity and mortality associated with Acanthamoeba keratitis and Acanthamoeba encephalitis, respectively. The discovery of a plethora of antiacanthamoebic compounds has not yielded effective marketed chemotherapeutics. The rate of development of novel antiacanthamoebic chemotherapies of translational value and the lack of interest of the pharmaceutical industry in developing such chemotherapies have been disappointing. On the other hand, the market for contact lenses/contact lens disinfectants is a multi-billion-dollar industry and has been successful and profitable. A better understanding of drugs, their targets, and mechanisms of action will facilitate the development of more-effective chemotherapies. Here, we review the progress toward phenotypic drug discovery, emphasizing the shortcomings of useable therapies.
Among several animals, Rattus rattus (rat) lives in polluted environments and feeds on organic waste/small invertebrates, suggesting the presence of inherent mechanisms to thwart infections. In this study, we isolated gut bacteria of rats for their antibacterial activities. Using antibacterial assays, the findings showed that the conditioned media from selected bacteria exhibited bactericidal activities against Gram-negative (Escherichia coli K1, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens, and Salmonella enterica) and Gram-positive (Bacillus cereus, methicillin-resistant Staphylococcus aureus, and Streptococcus pyogenes) pathogenic bacteria. The conditioned media retained their antibacterial properties upon heat treatment at boiling temperature for 10 min. Using MTT assays, the conditioned media showed minimal cytotoxic effects against human keratinocyte cells. Active conditioned media were subjected to tandem mass spectrometry, and the results showed that conditioned media from Bacillus subtilis produced a large repertoire of surfactin and iturin A (lipopeptides) molecules. To our knowledge, this is the first report of isolation of lipopeptides from bacteria isolated from the rat gut. In short, these findings are important and provide a platform to develop effective antibacterial drugs.
Cell impurities are an emerging nucleating molecular barriers having the capability in disordering the metabolic chain reactions of proteolysis, glycolysis and lipolysis. Their massive effects induced by copolymer crystal growth in compaction with metal and mineral transients are extended as well as in damaging DNA and mRNA structure motif and other molecular assembly e.g. histones structure unites. Their polycrystalline packing modes, polydispersity and their tendency to surface and interface adhesion prompted us in structuring scaffold biomaterials enriched with biopeptides, layered by phospho-glycerides ester-forms. The interface tension of the formed map is flexible and dependent to the surface exposure and its collapse modes to the surrounding molecular ligands. Thus, the attempts in increasing surface exposure e.g. the viscoelastic of structured lipopeptides and types of formed network structures interplays an extra- conjugating biomolecules having a least cytotoxicity effects to cells constituents. Disulfides molecules are selected to be the key regulatory element in rejoining both lipidic and proteic moieties by disordering atoms status via chemical ionization using organic catalyst. The insertion of methionine based peptidic chain at the lateral surfaces of scaffold biomaterials enhances the electron-meta-static motions by raising a molecular disordering status at distinct regions of the map e.g. epimerization into a nonpolar side that helps the chemical conjunction of disulfide groups with the esterified phosphoglycerides mono-layers. These effects in turn are accomplished by the formation of meso-sphere nonpolar- vesicles. The oxidation of disulfide group would alter the ordering of initial molecules by raising a newly molecular disorders to the map with high polarity to surface regions. In the same time indicates a continuation in the crystallization growth factor via a low chemical lesions between the impurities and a supersaturation in the intra-atomic distances with maximum cross linking to the deformed ligand with scaffold biomaterials.
A taxonomic study was carried out on strain A-11-3(T), which was isolated from an oil-enriched consortia from the surface seawater of Hong-Deng dock in the Straits of Malacca and Singapore. Cells were aerobic, Gram-negative, non-spore-forming irregular rods. The strain was catalase- and oxidase-negative. It grew on a restricted spectrum of organic compounds, including some organic acids and alkanes. 16S rRNA gene sequence comparisons showed that strain A-11-3(T) was most closely related to the type strains of Alcanivorax jadensis (96.8 % sequence similarity), Alcanivorax borkumensis (96.8 %), Alcanivorax dieselolei (94.8 %), Alcanivorax venustensis (94.2 %) and Alcanivorax balearicus (94.0 %). The predominant fatty acids were C(16 : 0) (31.2 %), C(18 : 1)omega7c (24.8 %), C(18 : 0) (9.6 %), C(12 : 0) (8.3 %), C(16 : 1)omega7c (8.3 %) and C(16 : 0) 3-OH (5.1 %). The G+C content of the genomic DNA was 54.7 mol%. Moreover, the strain produced lipopeptides as its surface-active compounds. According to physiological and biochemical tests, DNA-DNA hybridization results and sequence comparisons of the 16S-23S internal transcribed spacer, the gyrB gene and the alkane hydroxylase gene alkB1, strain A-11-3(T) was affiliated with the genus Alcanivorax but could be readily distinguished from recognized Alcanivorax species. Therefore strain A-11-3(T) represents a novel species of the genus Alcanivorax for which the name Alcanivorax hongdengensis sp. nov. is proposed. The type strain is A-11-3(T) (=CGMCC 1.7084(T)=LMG 24624(T)=MCCC 1A01496(T)).
In the Asia-Pacific region, Candida albicans is the predominant Candida species causing invasive candidiasis/candidemia in Australia, Japan, Korea, Hong Kong, Malaysia, Singapore and Thailand whereas C. tropicalis is the most frequently encountered Candida species in Pakistan and India. Invasive isolates of C. albicans, C. parapsilosis complex and C. tropicalis remain highly susceptible to fluconazole (>90% susceptible). Fluconazole resistance (6.8-15%), isolates with the non-wild-type phenotype for itraconazole susceptibility (3.9-10%) and voriconazole (5-17.8%), and echinocandin resistance (2.1-2.2% in anidulafungin and 2.2% in micafungin) among invasive C. glabrata complex isolates are increasing in prevalence. Moreover, not all isolates of C. tropicalis have been shown to be susceptible to fluconazole (nonsusceptible rate, 5.7-11.6% in China) or voriconazole (nonsusceptible rate, 5.7-9.6% in China).