Synthase Type Research Articles

Macrophages loaded with dendrimer-entrapped gold nanoparticles as a theranostic platform for CT imaging-guided combinational therapy of orthotopic osteosarcoma

Immune cell therapy has recently emerged as a promising treatment modality for malignant tumors. Specifically, nanoparticle-mediated cell-immunotherapy has attracted considerable attention due to the combined contributions of the biological regulation of nanoparticles and the intrinsic nature of immune cells. Herein, engineered macrophages with dendrimer-entrapped gold nanoparticles (Au [email protected]) were designed as a theranostic cell platform, for the first time, for CT imaging-guided cell immunotherapy and chemotherapy of osteosarcoma. In this study, Au DENPs were synthesized and used to activate macrophages into the anti-tumorigenic M1-like phenotype, characterized by the increased expression of CD86, the inducible type of nitric oxide synthase (iNOS), and tumor necrosis factor-α (TNF-α). After loading Au DENPs, the engineered macrophages showed cytostatic/pro-apoptotic effects against cancer cells and achieved CT imaging performance in vitro and in vivo. The combination of cell therapy and chemotherapy demonstrated a cooperative impact in enhancing cancer treatment. Our findings reveal that Au [email protected] can be used as a theranostic platform for osteosarcoma, which may present a brand‐new strategy for immune cell-combined chemotherapy of other cancer types.

Structural Determination, Biological Function, and Molecular Modelling Studies of Sulfoaildenafil Adulterated in Herbal Dietary Supplement.

Unapproved ingredients included in herbal medicines and dietary supplements have been detected as adulterated synthetic drugs used for erectile dysfunction. Extraction from a dietary supplement was performed to isolate the compounds by HPLC analysis. The structural characterization was confirmed using mass spectrometry (ESI-TOF/MS and LC-MS/MS), 1H NMR, and 13C NMR spectroscopy techniques. Results identified the thus-obtained compound to be sulfoaildenafil, a thioketone analogue of sildenafil. The biological activities of this active compound have been focused for the first time by the experimental point of view performance in vitro. The results revealed that sulfoaildenafil can affect the therapeutic level of nitric oxide through the upregulation of nitric oxide synthase and phosphodiesterase type 5 (PDE5) gene expressions. This bulk material, which displays structural similarity to sildenafil, was analyzed for the presence of a PDE5 inhibitor using a theoretical calculation. These unique features of the potential activity of PDE5 protein and its inhibitors, sildenafil and sulfoaildenafil, may play a key consideration for understanding the mode of actions and predicting the biological activities of PDE5 inhibitors.

Accidental feeding of the coccidiostat nicarbazin in layer breeder flocks - A case report

Following the accidental feeding of a compound feed containing the coccidiostat nicarbacin in layer breeder flocks (Lohmann Brown Classic), the birds displayed distinct clinical signs within a few hours. Mortality increased during the following 5 days, whereas laying performance and hatching rate of eggs during this period decreased markedly. Egg shell discoloration was observed as early as during the first day. As a consequence, an association between feeding of the coccidiostat nicarbacin and the observed symptoms was assumed. Recent studies indicate that Nicarbacin reduces the activity of aminolevulinic acid synthase type 1 (ALAS 1), which is responsible for the synthesis of protoporphyrin IX in the shell gland as main compound of brown egg shells. Reduced laying performance and increased mortality was likely due to nicarbacin-induced deregulated body temperature homeostasis and concomitant imbalances in acid-base status of the animals. The case reveals that the accidental feeding of nicarbacin to non-target animals such as laying hens and their parents may result in acute clinical symptoms. This highlights the necessity of appropriate care in handling feed additives and their premixes for specific non-target animals and should sensitize farmers and veterinarians.

Biochemical Characterization and Function of Eight Microbial Type Terpene Synthases from Lycophyte Selaginella moellendorffii

Selaginella moellendorffii is a lycophyte, a member of an ancient vascular plant lineage. Two distinct types of terpene synthase (TPS) genes were identified from this species, including S. moellendorffii TPS genes (SmTPSs) and S. moellendorffii microbial TPS-like genes (SmMTPSLs). The goal of this study was to investigate the biochemical functions of SmMTPSLs. Here, eight full-length SmMTPSL genes (SmMTPSL5, -15, -19, -23, -33, -37, -46, and -47) were functionally characterized from S. moellendorffii. Escherichia coli-expressed recombinant SmMTPSLs were tested for monoterpenes synthase and sesquiterpenes synthase activities. These enzymatic products were typical monoterpenes and sesquiterpenes that have been previous shown to be generated by typical plant TPSs when provided with geranyl diphosphate (GPP) and farnesyl diphosphate (FPP) as the substrates. Meanwhile, SmMTPSL23, -33, and -37 were up-regulated when induced by alamethicin (ALA) and methyl jasmonate (MeJA), suggesting a role for these genes in plants response to abiotic stresses. Furthermore, this study pointed out that the terpenoids products of SmMTPSL23, -33, and -37 have an antibacterial effect on Pseudomonas syringae pv. tomato DC3000 and Staphylococcus aureus. Taken together, these results provide more information about the catalytic and biochemical function of SmMTPSLs in S. moellendorffii plants.

Anti-photoaging activities of Sorbaria kirilowii ethanol extract in UVB-damaged cells.

Sorbaria kirilowii (Regel) Maxim, a plant found in China, Korea, Japan, and east of Europe, is a common herb used for traditional medicinal purposes. However, its ability to prevent photoaging has not been studied. In this study, we investigated the anti-photoaging functions of an ethanol extract (Sk-EE) of S. kirilowii (Regel) Maxim using human keratinocytes exposed to UVB. First, we analyzed the cytotoxicity of Sk-EE. Then, we determine the expression of genes related to inflammation, collagen degradation, and moisture retention. We also explored the anti-photoaging mechanism of Sk-EE by determining correlated signaling pathways and target molecules using reporter gene assays and immunoblotting analyses. Sk-EE treatment of cells increased hyaluronic acid synthase (HAS), filaggrin (FLG), and collagen type I alpha 1 (COL1A1) expression. Sk-EE dose-dependently inhibited the UVB-induced expression of matrix metalloproteinases (MMPs) 1, 2, 9 and cyclooxygenase (COX)-2 by blocking the activator protein (AP)-1 signaling pathway, in particular the phosphorylation of c-Jun N-terminal kinase (JNK), p38, and extracellular response kinase (ERK). In addition, c-Fos and c-Jun were targeted by Sk-EE. Our results indicate that Sk-EE has anti-inflammatory and skin-protective properties, and could be a candidate to treat signs of photoaging.

Leptin ameliorates testicular injury by altering expression of nitric oxide synthases in diabetic rats.

We aimed to evaluate the effects of leptin and nitro-L-arginine methyl ester hydrochloride (L-NAME) on testicular damage and expression of nitric oxide synthase (NOS) types (neuronal, endothelial and inducible NOS) in streptozotocin (STZ) -induced diabetic and non-diabetic rats. Testicular damage was evaluated histologically and expression of NOSs was evaluated immunohistochemically in testis. Plasma leptin level and blood glucose level were assessed. Blood glucose levels increased in all diabetic groups. L-NAME reduced it, but leptin had no effect. Three types NOS expression were shown in germ cells immunohistochemically. Increased eNOS and iNOS expression and decreased nNOS expression was detected in diabetic group. Testicular damage was observed in diabetic groups. Leptin ameliorated the damage by reducing iNOS expression and L-NAME partially prevented injury by supressing excessive NO production in diabetic rats. It can be suggested that leptin and L-NAME partially prevents testicular damage by ameliorating histopathological changes by stimulating and /or supressing three types of NOS expression in diabetic rats. Leptin exhibited its effects by reducing iNOS expression in diabetic rats. This is the first report demonstrating the relationship between leptin and nitric oxide in testicular tissue in STZ-induced diabetic rats (Fig. 3, Ref. 33).

Marine actinomycetes from Malaysia marine environments with antagonistic potential

Marine actinomycetes have garnered the attention of researchers worldwide due to their ability to produce unique and novel bioactive compounds. This study aimed at assessing the diversity and antagonistic potential of marine actinomycetes isolated from Langkawi Island, Kedah and Tioman Island, Johor. In a total of 215 isolates were successfully recovered of which 52% were obtained from Starch–yeast Extract Agar (SYE), 31.4% from Marine Agar (MA) and 16.3% from Actinomycetes Isolation Agar. Fourteen isolates were found to be positive of Polyketide Synthase Type I (PKS-I) and/or Non-ribosomal Peptide Synthetases (NRPS) genes and these isolates were then subjected to antimicrobial evaluation test against 3 Gram-positive bacteria – Staphylococcus aureus, Methicillinresistant S. aureus, Bacillus subtilis; 4 Gram-negative bacteria – Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Serratia marcescens; and 2 fungi – Candida albicans, Candida parapsilosis. Most isolates were able to inhibit at least one test microorganism. There is, however, no direct correlation between the presence of the biosynthetic genes and antagonistic potential as demonstrated by the lack of antimicrobial activity though PKS-I and/or NRPS genes were present. Molecular identification using the 16S rRNA gene revealed 10 isolates belonging to the genus Streptomyces and each representative of the genera Actinomadura, Rhodococcus, Gordonia and Salinispora. Among the isolates, Streptomyces sp. T55 is a potent antibacterial actinomycete while Streptomyces sp. T109 is a good antifungal agent. Further characterization of marine actinomycetes was conducted using scanning electron microscopy, culture characteristics on several media (SYE, MA, Potato Dextrose Agar, ISP2, ISP3, ISP4, Czapek Agar), NaCl tolerance and carbon sources utilization profile using BIOLOG. Findings from this study demonstrate the potential of Malaysia’s marine environment as a new resource of actinomycetes with biosynthetic capabilities which can be further explored for the development of the natural product.

MltG activity antagonizes cell wall synthesis by both types of peptidoglycan polymerases in Escherichia coli.

Bacterial cells are surrounded by a peptidoglycan (PG) cell wall. This structure is essential for cell integrity and its biogenesis pathway is a key antibiotic target. Most bacteria utilize two types of synthases that polymerize glycan strands and crosslink them: class A penicillin-binding proteins (aPBPs) and complexes of SEDS proteins and class B PBPs (bPBPs). Although the enzymatic steps of PG synthesis are well characterized, the steps involved in terminating PG glycan polymerization remain poorly understood. A few years ago, the conserved lytic transglycosylase MltG was identified as a potential terminase for PG synthesis in Escherichia coli. However, characterization of the in vivo function of MltG was hampered by the lack of a growth or morphological phenotype in ΔmltG cells. Here, we report the isolation of MltG-defective mutants as suppressors of lethal deficits in either aPBP or SEDS/bPBP PG synthase activity. We used this phenotype to perform a domain-function analysis for MltG, which revealed that access to the inner membrane is important for its in vivo activity. Overall, our results support a model in which MltG functions as a terminase for both classes of PG synthases by cleaving PG glycans as they are being actively synthesized.

A Novel Endocrine Role for the BAT-Released Lipokine 12,13-diHOME to Mediate Cardiac Function.

Brown adipose tissue (BAT) is an important tissue for thermogenesis, making it a potential target to decrease the risks of obesity, type 2 diabetes, and cardiovascular disease, and recent studies have also identified BAT as an endocrine organ. Although BAT has been implicated to be protective in cardiovascular disease, to this point there are no studies that identify a direct role for BAT to mediate cardiac function. To determine the role of BAT on cardiac function, we utilized a model of BAT transplantation. We then performed lipidomics and identified an increase in the lipokine 12,13-dihydroxy-9Z-octadecenoic acid (12,13-diHOME). We utilized a mouse model with sustained overexpression of 12,13-diHOME and investigated the role of 12,13-diHOME in a nitric oxide synthase type 1 deficient (NOS1-/-) mouse and in isolated cardiomyocytes to determine effects on function and respiration. We also investigated 12,13-diHOME in a cohort of human patients with heart disease. Here, we determined that transplantation of BAT (+BAT) improves cardiac function via the release of the lipokine 12,13-diHOME. Sustained overexpression of 12,13-diHOME using tissue nanotransfection negated the deleterious effects of a high-fat diet on cardiac function and remodeling, and acute injection of 12,13-diHOME increased cardiac hemodynamics via direct effects on the cardiomyocyte. Furthermore, incubation of cardiomyocytes with 12,13-diHOME increased mitochondrial respiration. The effects of 12,13-diHOME were absent in NOS1-/- mice and cardiomyocytes. We also provide the first evidence that 12,13-diHOME is decreased in human patients with heart disease. Our results identify an endocrine role for BAT to enhance cardiac function that is mediated by regulation of calcium cycling via 12,13-diHOME and NOS1.

MicroRNA-1291-5p Sensitizes Pancreatic Carcinoma Cells to Arginine Deprivation and Chemotherapy through the Regulation of Arginolysis and Glycolysis.

Cancer cells are dysregulated and addicted to continuous supply and metabolism of nutritional glucose and amino acids (e.g., arginine) to drive the synthesis of critical macromolecules for uncontrolled growth. Recent studies have revealed that genome-derived microRNA (miRNA or miR)-1291-5p (miR-1291-5p or miR-1291) may modulate the expression of argininosuccinate synthase (ASS1) and glucose transporter protein type 1 (GLUT1). We also developed a novel approach to produce recombinant miR-1291 agents for research, which are distinguished from conventional chemo-engineered miRNA mimics. Herein, we firstly demonstrated that bioengineered miR-1291 agent was selectively processed to high levels of target miR-1291-5p in human pancreatic cancer (PC) cells. After the suppression of ASS1 protein levels, miR-1291 perturbed arginine homeostasis and preferably sensitized ASS1-abundant L3.3 cells to arginine deprivation therapy. In addition, miR-1291 treatment reduced the protein levels of GLUT1 in both AsPC-1 and PANC-1 cells, leading to a lower glucose uptake (deceased > 40%) and glycolysis capacity (reduced approximately 50%). As a result, miR-1291 largely improved cisplatin efficacy in the inhibition of PC cell viability. Our results demonstrated that miR-1291 was effective to sensitize PC cells to arginine deprivation treatment and chemotherapy through targeting ASS1- and GLUT1-mediated arginolysis and glycolysis, respectively, which may provide insights into understanding miRNA signaling underlying cancer cell metabolism and development of new strategies for the treatment of lethal PC.SIGNIFICANCE STATEMENTMany anticancer drugs in clinical use and under investigation exert pharmacological effects or improve efficacy of coadministered medications by targeting cancer cell metabolism. Using new recombinant miR-1291 agent, we revealed that miR-1291 acts as a metabolism modulator in pancreatic carcinoma cells through the regulation of argininosuccinate synthase– and glucose transporter protein type 1–mediated arginolysis and glycolysis. Consequently, miR-1291 effectively enhanced the efficacy of arginine deprivation (pegylated arginine deiminase) and chemotherapy (cisplatin), offering new insights into development of rational combination therapies.

Признаки дисплазии соединительной ткани и ген эндотелиальной синтазы азота 3 типа (NOS3) при синдроме Вольфа–Паркинсона–Уайта

Признаки дисплазии соединительной ткани и ген эндотелиальной синтазы азота 3 типа (NOS3) при синдроме Вольфа–Паркинсона–Уайта

Biocontrol potential of Streptomyces sp. CACIS-1.5CA against phytopathogenic fungi causing postharvest fruit diseases

BackgroundFungi are one of the microorganisms that cause most damage to fruits worldwide, affecting their quality and consumption. Chemical controls with pesticides are used to diminish postharvest losses of fruits. However, biological control with microorganisms or natural compounds is an increasing alternative to protect fruits and vegetables. In this study, the antifungal effect of Streptomyces sp. CACIS-1.5CA on phytopathogenic fungi that cause postharvest tropical fruit rot was investigated.Main bodyAntagonistic activity was evaluated in vitro by the dual confrontation over fungal isolates obtained from grape, mango, tomato, habanero pepper, papaya, sweet orange, and banana. The results showed that antagonistic activity of the isolate CACIS-1.5CA was similar to the commercial strain Streptomyces lydicus WYEC 108 against the pathogenic fungi Colletotrichum sp., Alternaria sp., Aspergillus sp., Botrytis sp., Rhizoctonia sp., and Rhizopus sp. with percentages ranging from 30 to 63%. The bioactive extract obtained from CACIS-1.5 showed a strong inhibition of fungal spore germination, with percentages ranging from 92 to 100%. Morphological effects as irregular membrane border, deformation, shrinkage, and collapsed conidia were observed on the conidia. Molecularly, the biosynthetic clusters of genes for the polyketide synthase (PKS) type I, PKS type II, and NRPS were detected in the genome of Streptomyces sp. CACIS-1.5CA.ConclusionsThis study presented a novel Streptomyces strain as a natural alternative to the use of synthetic fungicides or other commercial products having antagonistic microorganisms that were used in the postharvest control of phytopathogenic fungi affecting fruits.

Testosterone positively regulates functional responses and nitric oxide expression in the isolated human corpus cavernosum.

Testosterone (T) deficiency is associated with erectile dysfunction (ED). The relaxant response of T on the corporal smooth muscle through a non-genomic pathwayhas been reported; however, the in vitro modulating effects ofTon human corpus cavernosum (HCC) have not been studied. To compare the effects of various concentrations of T on nitric oxide (NO)-dependent and nitric oxide-independent relaxation in organ bath studies and elucidate its mode of action, specifically targeting the cavernous NO/cyclic guanosine monophosphate (cGMP) pathway. Human corpus cavernosum (HCC) samples were obtained from men undergoing penile prosthesis implantation (n=9). After phenylephrine (Phe) precontraction, the effects of various relaxant drugs of HCC strips were performed using organ bath at low (150ng/dL), eugonadal (400ng/dL), and hypergonadal (600ng/dL) T concentrations. The penile tissue measurements of endothelial nitric oxide synthase (eNOS), neuronal (n)NOS, and phosphodiesterase type 5 (PDE5) were evaluated via immunostaining, Western blot, cGMP and nitrite/nitrate (NOx) assays. Relaxation responses to ACh and EFS in isolated HCC strips were significantly increased at all T levels compared with untreated tissues. The sildenafil-induced relaxant response was significantly increased at both eugonadal and hypergonadal T levels. Normal and high levels of T are accompanied by increased eNOS, nNOS, cGMP, and NOx levels, along with reduced PDE5 protein expression. This study reveals an important role of short-term and modulatory effects of different concentrations of T in HCC. T positively regulates functional activities, inhibition of PDE5 expression, and formation of cGMP and NOx in HCC. These results demonstrate that T indirectly contributes to HCC relaxation via downstream effects on nNOS, eNOS, and cGMP and by inhibiting PDE5. This action provides a rationale for normalizing T levels in hypogonadal men with ED, especially when PDE5 inhibitors are ineffective. T replacement therapy may improve erectile function by modulating endothelial function in hypogonadal men.

Development of a novel thymidylate synthase (TS) inhibitor capable of up-regulating P53 expression and inhibiting angiogenesis in NSCLC

IntroductionThe development of a new type of Thymidylate synthase (TS) inhibitor that could inhibit cancer cells' proliferation and anti-angiogenesis is of great significance for cancer's clinical treatment. ObjectivesOur research hopes to develop a TS inhibitor that is more effective than the current first-line clinical treatment of pemetrexed (PTX) and provide a new reference for the clinical treatment of non-small cell lung cancer (NSCLC). MethodsWe obtained a series of novel TS inhibitors by chemical synthesis. Moreover, TS assay and molecular docking to verify the target compound's inhibitory mode. Use MTT assay, colony-forming assay, flow cytometry, and western blot to verify the compound's inhibitory effect on cancer cell proliferation and its mechanism; and explore the compound’s effect on angiogenesis in vitro and in vivo. Further, explore the hit compound's anti-cancer ability through the xenograft tumor model and the orthotopic cancer murine model. ResultsA series of N-(3-(5-phenyl-1,3,4-oxadiazole-2-yl) phenyl)-2,4-dihydroxypyrimidine-5-sulfamide derivatives were synthesized as TS inhibitors for the first time. All target compounds significantly inhibited hTS enzyme activity and demonstrated significant antitumor activity against five cancer cell lines. Notably, 7f had a high selectivity index (SI) and unique inhibitory effects on eight NSCLC cells. In-depth research indicated that 7f could induce apoptosis by the mitochondrial pathway in A549 and PC-9 cells through the upregulation of wild-type P53 protein expression. Additionally, 7f was shown to inhibit angiogenesis in vitro and in vivo. In vivo studies, compared to PTX, 7f significantly inhibited tumor growth in A549 cell xenografts and had a higher therapeutic index (TGI). Moreover, 7f could prolong the survival of the orthotopic lung cancer murine model more effectively than PTX. ConclusionThe anti-angiogenic effect of 7f provides a new reference for the development of TS inhibitors and the clinical treatment of NSCLC.

IL-22 Promotes IFN-γ-Mediated Immunity against Histoplasma capsulatum Infection.

Histoplasma capsulatum is the agent of histoplasmosis, one of the most frequent mycoses in the world. The infection initiates with fungal spore inhalation, transformation into yeasts in the lungs and establishment of a granulomatous disease, which is characterized by a Th1 response. The production of Th1 signature cytokines, such as IFN-γ, is crucial for yeast clearance from the lungs, and to prevent dissemination. Recently, it was demonstrated that IL-17, a Th17 signature cytokine, is also important for fungal control, particularly in the absence of Th1 response. IL-22 is another cytokine with multiple functions on host response and disease progression. However, little is known about the role of IL-22 during histoplasmosis. In this study, we demonstrated that absence of IL-22 affected the clearance of yeasts from the lungs and increased the spreading to the spleen. In addition, IL-22 deficient mice (Il22−/−) succumbed to infection, which correlated with reductions in the numbers of CD4+ IFN-γ+ T cells, reduced IFN-γ levels, and diminished nitric oxide synthase type 2 (NOS2) expression in the lungs. Importantly, treatment with rIFN-γ mitigated the susceptibility of Il22−/− mice to H. capsulatum infection. These data indicate that IL-22 is crucial for IFN-γ/NO production and resistance to experimental histoplasmosis.

P0116DISCOVERY OF A NOVEL ANTIMICROBIAL COMPOUND AGAINST PSEUDOMONAS AERUGINOSA FROM URINE OF KTX PATIENTS

Abstract Background and Aims The urinary microbiome harbors a great repertoire of bacteria, which possess an immense potential for the biosynthesis of different biochemical products such as polyketide synthases. Traditionally such compounds have been utilized as pharmaceutical drugs, for example as antibiotics or cytostatic substances or agrochemical agents. While examining the urinary microbiome of KTX-patients during AKI and concomitant antibiotic treatment a remarkable decrease of Candidatus solibacter usitatus in one patient attracted our attention. Surprised about detecting a putative close relative of a bacterium, which originally has been found in Australian soil in our patient’s urine, we examined the genome and protein coding regions of Candidatus solibacter usitatus. Thereby we identified a biosynthetic pathway, which allowed us to clone and produce an up-to-now unknown polyketide type 1 synthase, which we named Dananase. Method The dananase gene was synthesized, cloned into the pEX-A258 for replication and inserted into the p-TOPO-entry-D gateway vector following PCR amplification. The resultant insert was shifted into the pEXP1- DEST gateway vector. E. coli transformants were selected for dananase expression. BAP1-E. coli was transformed with the dananase-pEXP1- DEST expression plasmid and grown in liquid culture under induction with IPTG. The supernatant was filtered and utilized for antimicrobial activity testing against Pseudomonas aeruginosa. Metabolome analysis of BAP1- pEXP1-DEST-dananase following induction with IPDG was performed and compared to LB-media alone and supernatants of dummy plasmid transformed BAP1-E. coli. In addition, the molecular structure of dananase product was determined using trans-AT polyketide synthase predictor web application genome mining tool. Results The 1646 amino acid long polyketide synthase type 1 named dananase was cloned into pEXP1 expression vector and expressed in BAP1. The supernatant contained specific antimicrobial activity against clinical isolates of Pseudomonas aeruginosa. This highly active compound could be further purified by HPLC but not yet identified in its structure. In silico prediction analysis suggested a polyketide as follows CC(C(O)*)C=CC(CC(NC([K])C(CC(O)=O)=O)=O)=O. Mass spectrometric analysis revealed several Dananase-specific peaks representing most likely its product in the supernatant. Conclusion The dananase gene of Candidatus solibacter usitatus consists of 4941bp and encodes a polymodular polyketide synthase type-1, its product successfully inhibits growth of Pseudomonas aeruginosa in vitro.

In Silico Identification of Type III PKS Chalcone and Stilbene Synthase Homologs in Marine Photosynthetic Organisms.

Marine microalgae are photosynthetic microorganisms at the base of the marine food webs. They are characterized by huge taxonomic and metabolic diversity and several species have been shown to have bioactivities useful for the treatment of human pathologies. However, the compounds and the metabolic pathways responsible for bioactive compound synthesis are often still unknown. In this study, we aimed at analysing the microalgal transcriptomes available in the Marine Microbial Eukaryotic Transcriptome Sequencing Project (MMETSP) database for an in silico search of polyketide synthase type III homologs and, in particular, chalcone synthase (CHS) and stilbene synthase (STS), which are often referred to as the CHS/STS family. These enzymes were selected because they are known to produce compounds with biological properties useful for human health, such as cancer chemopreventive, anti-inflammatory, antioxidant, anti-angiogenic, anti-viral and anti-diabetic. In addition, we also searched for 4-Coumarate: CoA ligase, an upstream enzyme in the synthesis of chalcones and stilbenes. This study reports for the first time the occurrence of these enzymes in specific microalgal taxa, confirming the importance for microalgae of these pathways and giving new insights into microalgal physiology and possible biotechnological applications for the production of bioactive compounds.

Evaluation of Antagonistic and Plant Growth Promoting Potential of Streptomycessp. TT3 Isolated from Tea(Camellia sinensis) Rhizosphere Soil.

The present study investigated the antagonistic and plant growth promoting (PGP) potential of actinobacteria TT3 isolated from tea rhizosphere soil of Tocklai tea germplasm preservation plot, Jorhat, Assam, India. It is a Gram-positive, filamentous with flexible spore chains actinobacteria. The 16S rRNA gene sequencing and phylogenetic analysis indicated that TT3 is closely related to genus Streptomyces for which it was referred to as Streptomyces sp. TT3. It showed very promising PGP traits such as phosphate solubilization, production of indole acetic acid (IAA), siderophore, and ammonia. Evaluation of ethyl acetate extract of TT3 exhibited broad spectrum antagonistic activity against various fungal pathogens. This antagonistic Streptomyces sp. TT3 showed positive for polyketide synthase type II (PKS-II) gene, which was predicted to be involved in the production of actinorhodin as a secondary metabolite pathway product using DoBISCUIT database. Further, the crude ethyl acetate extract of TT3 was analyzed by using GC-MS and revealed the presence of significant chemical constituents responsible for antimicrobial activity. Thus, the present study suggests that actinobacteria isolated from the rhizosphere soil may be explored for the production of bioactive compounds and use as a potential candidate for tea and other agricultural application.

Isolation of endophytic fungi from South African plants, and screening for their antimicrobial and extracellular enzymatic activities and presence of type I polyketide synthases

Endophytes are bacteria or fungi which live inside the host plant and participate in many biological processes without causing disease or other adverse effects. Endophytes are recognised as a rich source of secondary metabolites with potentially useful pharmacological properties. Many South African medicinal plants are highly under-investigated sources of potentially useful endophytic microbes. In this report six endophytic fungi were obtained from the leaves, stems and roots of South African medicinal plants which are known for their traditional uses and pharmacological properties. The endophytic fungi were isolated from Cotyledon orbiculata L., Psychotria zombamontana (Kuntze) Petit, Tecomaria capensis (Thunb.) Lindl., Catha edulis (Vahl) Endl. and Melianthus comosus Vahl. The crude extracts of the isolated endophytic fungi were investigated for their antimicrobial potential, extracellular enzymatic activity and phosphate solubilization. Additionally, the present study used genetic screening to assess the ability of the endophytic fungi to synthesize bioactive compounds, indicated by the presence of the polyketide synthase type 1 (PKS 1) gene. In preliminary microbial inhibition screening the fungal extracts had promising antifungal activity against Cryptococcus neoformans and Candida albicans. Furthermore, the endophytic fungus Talaromyces funiculosus displayed extracellular enzymatic activity, namely xylanase and cellulase. Five fungal strains demonstrated ability to solubilize phosphate and three strains demonstrated the presence of polyketide synthase type 1 (PKS 1) gene. It is worth considering further investigation of their bioactive secondary metabolites.

Downregulation of thioredoxin-1-dependent CD95 S-nitrosation by Sorafenib reduces liver cancer

Hepatocellular carcinoma (HCC) represents 80% of the primary hepatic neoplasms. It is the sixth most frequent neoplasm, the fourth cause of cancer-related death, and 7% of registered malignancies. Sorafenib is the first line molecular targeted therapy for patients in advanced stage of HCC. The present study shows that Sorafenib exerts free radical scavenging properties associated with the downregulation of nuclear factor E2-related factor 2 (Nrf2)-regulated thioredoxin 1 (Trx1) expression in liver cancer cells. The experimental downregulation and/or overexpression strategies showed that Trx1 induced activation of nitric oxide synthase (NOS) type 3 (NOS3) and S-nitrosation (SNO) of CD95 receptor leading to an increase of caspase-8 activity and cell proliferation, as well as reduction of caspase-3 activity in liver cancer cells. In addition, Sorafenib transiently increased mRNA expression and activity of S-nitrosoglutathione reductase (GSNOR) in HepG2 cells. Different experimental models of hepatocarcinogenesis based on the subcutaneous implantation of HepG2 cells in nude mice, as well as the induction of HCC by diethylnitrosamine (DEN) confirmed the relevance of Trx1 downregulation during the proapoptotic and antiproliferative properties induced by Sorafenib. In conclusion, the induction of apoptosis and antiproliferative properties by Sorafenib were related to Trx1 downregulation that appeared to play a relevant role on SNO of NOS3 and CD95 in HepG2 cells. The transient increase of GSNOR might also participate in the deactivation of CD95-dependent proliferative signaling in liver cancer cells.