Modifications to central carbon metabolism in an engineered Streptomyces host to enhance secondary metabolite production.

To improve the production of secondary metabolites by alternation of the carbon metabolic flux, two types of deletion mutants of the central metabolic pathway, the Embden-Meyerhof (EM) or pentose phosphate (PP) pathway, in the genetically engineered Streptomyces avermitilis were constructed. Double-deletion mutants of phosphofructokinase (ΔpfkA1ΔpfkA3) in the EM pathway carrying a gene cluster for chloramphenicol biosynthesis markedly increased chloramphenicol production synthesized through the shikimate pathway. Although the ΔpfkA1ΔpfkA3 double-deletion mutant grew more slowly, its specific productivity of chloramphenicol (per dry cell weight) was 2.

In vitro Cas9-assisted editing of modular polyketide synthase genes to produce desired natural product derivatives.

One major bottleneck in natural product drug development is derivatization, which is pivotal for fine tuning lead compounds. A promising solution is modifying the biosynthetic machineries of middle molecules such as macrolides. Although intense studies have established various methodologies for protein engineering of type I modular polyketide synthase(s) (PKSs), the accurate targeting of desired regions in the PKS gene is still challenging due to the high sequence similarity between its modules.

An Unusual Extender Unit Is Incorporated into the Modular Polyketide Synthase of Scopranones Biosynthesis.

Scopranones, produced by sp. BYK-11038, are the novel bone morphogenetic protein inhibitors characterized by atypical two scoop-like moieties and a 3-furanone moiety. Two scoop-like moieties connected to a 3-furanone have not previously been reported in natural products, and their biosynthesis must occur via a unique pathway.

Outbreaks of highly pathogenic avian influenza in zoo birds caused by HA clade 2.3.4.4 H5N6 subtype viruses in Japan in winter 2016.

In late 2016, two zoos, one in northern Japan and the other in central Japan, experienced highly pathogenic avian influenza (HPAI) outbreaks, in which multiple zoo birds were infected with H5N6 subtype HPAI virus (HPAIV). Here, we report an overview of these HPAI outbreaks. HPAIV infections were confirmed by virus isolation in three black swans (Cygnus atratus) and three snowy owls (Bubo scandiacus) kept in the Omoriyama Zoo hospital.

A Progressive Early Mobilization Program Is Significantly Associated With Clinical and Economic Improvement: A Single-Center Quality Comparison Study.

Objectives: To determine whether a progressive early mobilization protocol improves patient outcomes, including in-hospital mortality and total hospital costs.

Design: Retrospective preintervention and postintervention quality comparison study.

Settings: Single tertiary community hospital with a 12-bed closed-mixed ICU.

Distribution and functional analysis of the phosphopantetheinyl transferase superfamily in microorganisms.

Phosphopantetheinyl transferases (PPTases) are a superfamily of essential enzymes required for the synthetic processes of many compounds including fatty acid, polyketide, and nonribosomal peptide metabolites. These enzymes activate carrier proteins in specific biosynthetic pathways via the transfer of a phosphopantetheinyl moiety to a serine residue in the conserved motif of carrier proteins. Since many microorganisms produce a number of polyketide and nonribosomal peptide metabolites, the distribution of PPTase genes was investigated in these microorganisms.

Neothioviridamide, a Polythioamide Compound Produced by Heterologous Expression of a Streptomyces sp. Cryptic RiPP Biosynthetic Gene Cluster.

During genome mining for thioviridamide-like biosynthetic gene clusters that could produce polythioamide RiPP (ribosomally synthesized and post-translationally modified peptides), we discovered a novel cryptic biosynthetic gene cluster. During efforts to express this biosynthetic gene using heterologous expression of this biosynthetic gene cluster, a novel compound designated as neothioviridamide was produced. We report herein the cloning and heterologous expression of the neothioviridamide biosynthetic gene cluster and the isolation, structure determination, and cytotoxic activity of neothioviridamide.

Characterization of bafilomycin biosynthesis in Kitasatospora setae KM-6054 and comparative analysis of gene clusters in Actinomycetales microorganisms.

Bafilomycins A, C and B (setamycin) produced by Kitasatospora setae KM-6054 belong to the plecomacrolide family, which exhibit antibacterial, antifungal, antineoplastic and immunosuppressive activities. An analysis of gene clusters from K. setae KM-6054 governing the biosynthesis of bafilomycins revealed that it contains five large open reading frames (ORFs) encoding the multifunctional polypeptides of bafilomycin polyketide synthases (PKSs).

Heterologous production of kasugamycin, an aminoglycoside antibiotic from Streptomyces kasugaensis, in Streptomyces lividans and Rhodococcus erythropolis L-88 by constitutive expression of the biosynthetic gene cluster.

Kasugamycin (KSM), an aminoglycoside antibiotic isolated from Streptomyces kasugaensis cultures, has been used against rice blast disease for more than 50 years. We cloned the KSM biosynthetic gene (KBG) cluster from S. kasugaensis MB273-C4 and constructed three KBG cassettes (i.

High production of a class III lantipeptide AmfS in Streptomyces griseus.

AmfS, a class III lantipeptide serves as a morphogen in Streptomyces griseus. Here, we constructed a high production system of AmfS in S. griseus.

tRNA-Dependent Aminoacylation of an Amino Sugar Intermediate in the Biosynthesis of a Streptothricin-Related Antibiotic.

Unlabelled: The antibiotic streptothricin (ST) possesses an amino sugar bound to an l-β-lysine (β-Lys) residue via a peptide bond. The peptide bond formation has been shown to be catalyzed by a nonribosomal peptide synthetase (NRPS) during ST biosynthesis. The focus of this study is the closely related ST analogue BD-12, which carries a glycine-derived side chain rather than a β-Lys residue.

Chemical diversity of labdane-type bicyclic diterpene biosynthesis in Actinomycetales microorganisms.

Five pairs of bacterial type-A and type-B diterpene synthases have been characterized: BAD86798/BAD86797, AHK61133/AHK61132, BAB39207/BAB39206, CldD/CldB and RmnD/RmnB, and are involved in the formation of pimara-9(11),15-diene, terpente-3,13,15-triene and labda-8(17),12(E),14-triene. Mining of bacterial genome data revealed an additional four pairs of type-A and type-B diterpene synthases: Sros_3191/Sros_3192 of Streptosporangium roseum DSM 43021, Sare_1287/Sare_1288 of Salinispora arenicola CNS-205, SCLAV_5671/SCLAV_5672 and SCLAV_p0491/SCLAV_p0490 of Streptomyces clavuligerus ATCC 27064. Since SCLAV_p0491/SCLAV_p0490 is similar to the labdane-type diterpene synthase pairs, CldD/CldB and RmnD/RmnB based on the alignment of the deduced amino acid sequences and phylogenetic analyses of the aligned sequences, these predicted diterpene synthases were characterized by an enzymatic reaction using a pair of recombinant type-A and type-B diterpene synthases prepared in Escherichia coli and the heterologous expression of two genes encoding type-A and type-B diterpene synthases in an engineered Streptomyces host.

Reconstitution of L-Asparaginase in Siliconized Syringes with Shaking and Headspace Air Induces Protein Aggregation.

The aim of this study was to characterize protein aggregation during reconstitution of a highly concentrated solution of lyophilized L-asparaginase (L-ASP). The effect of the preparation method on L-ASP aggregation using siliconized or non-siliconized syringes and the effect of storage after preparation were evaluated by far-UV circular dichroism spectroscopy, Raman microscopy, flow cytometry, and flow particle image analysis. To investigate the effect of syringe type in combination with shaking and headspace air on L-ASP aggregation, four kinds of L-ASP in 5% glucose solutions were prepared (in the presence or absence of silicon oil and headspace air).

Terpene synthases are widely distributed in bacteria.

Odoriferous terpene metabolites of bacterial origin have been known for many years. In genome-sequenced Streptomycetaceae microorganisms, the vast majority produces the degraded sesquiterpene alcohol geosmin. Two minor groups of bacteria do not produce geosmin, with one of these groups instead producing other sesquiterpene alcohols, whereas members of the remaining group do not produce any detectable terpenoid metabolites.

Evaluation of the pharmaceutical characteristics of various enteric-coated aspirin tablets under different storage conditions.

The formulation characteristics of 6 brands of enteric-coated aspirin tablets under unpackaged conditions at 40°C and 60°C for 4 weeks were analyzed. Appearance, salicylic acid content, dissolution rates, and surface properties (by Raman microscopy) were evaluated to determine stability data, taking into account the clinical use of generic drugs. No change in appearance, decomposition, or dissolution rates was observed in unpackaged aspirin tablets stored at 40°C for 4 weeks.

Discovery of gene cluster for mycosporine-like amino acid biosynthesis from Actinomycetales microorganisms and production of a novel mycosporine-like amino acid by heterologous expression.

Mycosporines and mycosporine-like amino acids (MAAs), including shinorine (mycosporine-glycine-serine) and porphyra-334 (mycosporine-glycine-threonine), are UV-absorbing compounds produced by cyanobacteria, fungi, and marine micro- and macroalgae. These MAAs have the ability to protect these organisms from damage by environmental UV radiation. Although no reports have described the production of MAAs and the corresponding genes involved in MAA biosynthesis from Gram-positive bacteria to date, genome mining of the Gram-positive bacterial database revealed that two microorganisms belonging to the order Actinomycetales, Actinosynnema mirum DSM 43827 and Pseudonocardia sp.

Engineered Streptomyces avermitilis host for heterologous expression of biosynthetic gene cluster for secondary metabolites.

An industrial microorganism, Streptomyces avermitilis, which is a producer of anthelmintic macrocyclic lactones, avermectins, has been constructed as a versatile model host for heterologous expression of genes encoding secondary metabolite biosynthesis. Twenty of the entire biosynthetic gene clusters for secondary metabolites were successively cloned and introduced into a versatile model host S. avermitilis SUKA17 or 22.

Spontaneous Tyzzer's disease with the central nerve involvement in a newborn common marmoset.

A new-born (8-day-old) male marmoset (Callithrix jacchus) was found dead in a zoo. The littermate and parents had no clinical abnormalities. By gross observations at necropsy, there were moderate to severe multiple necrotic foci in the liver and heart.

Pleiotropic control of secondary metabolism and morphological development by KsbC, a butyrolactone autoregulator receptor homologue in Kitasatospora setae.

The γ-butyrolactone autoregulator signaling cascades have been shown to control secondary metabolism and/or morphological development among many Streptomyces species. However, the conservation and variation of the regulatory systems among actinomycetes remain to be clarified. The genome sequence of Kitasatospora setae, which also belongs to the family Streptomycetaceae containing the genus Streptomyces, has revealed the presence of three homologues of the autoregulator receptor: KsbA, which has previously been confirmed to be involved only in secondary metabolism; KsbB; and KsbC.

Site-specific genome integration in alphaproteobacteria mediated by TG1 integrase.

The serine-type phage integrase is an enzyme that catalyzes site-specific recombination between two attachment sites of phage and host bacterial genomes (attP and attB, respectively) having relatively short but distinct sequences without host auxiliary factor(s). Previously, we have established in vivo and in vitro site-specific recombination systems based on the serine-type integrase produced by actinophage TG1 and determined the minimal sizes of attP(TG1) and attB(TG1) sites required for the in vitro TG1 integrase reaction as 43- and 39-bp, respectively. Here, DNA databases were surveyed by FASTA program with the authentic attB(TG1) sequence of Streptomyces avermitilis as a query.

The autoregulator receptor homologue AvaR3 plays a regulatory role in antibiotic production, mycelial aggregation and colony development of Streptomyces avermitilis.

The γ-butyrolactone autoregulator receptor has been shown to control secondary metabolism and/or morphological differentiation across many Streptomyces species. Streptomyces avermitilis produces an important anthelmintic agent (avermectin) and two further polyketide antibiotics, filipin and oligomycin. Genomic analysis of S.

Characterization of a silent sesquiterpenoid biosynthetic pathway in Streptomyces avermitilis controlling epi-isozizaene albaflavenone biosynthesis and isolation of a new oxidized epi-isozizaene metabolite.

The genome-sequenced, Gram-positive bacterium Streptomyces avermitilis harbours an orthologue (SAV_3032) of the previously identified epi-isozizaene synthase (SCO5222) in Streptomyces coelicolor A3(2). The sav3032 is translationally coupled with the downstream sav3031 gene encoding the cytochrome P450 CYP170A2 analogous to SCO5223 (CYP170A1) of S. coelicolor A3(2), which exhibits a similar translation coupling.

Pentalenic acid is a shunt metabolite in the biosynthesis of the pentalenolactone family of metabolites: hydroxylation of 1-deoxypentalenic acid mediated by CYP105D7 (SAV_7469) of Streptomyces avermitilis.

Pentalenic acid (1) has been isolated from many Streptomyces sp. as a co-metabolite of the sesquiterpenoid antibiotic pentalenolactone and related natural products. We have previously reported the identification of a 13.