Cyanobacterial growth and cyanophycin production with urea and ammonium as nitrogen source

Several technologies have aimed to recover nitrogen directly from urine. Nitrogen recovery in these technologies was limited by the mismatch of the nitrogen-phosphorus molar ratio (N:P) of urine, being 30–46:1, and that of the final product, e.g., 1:1 in struvite and 16–22:1 in microalgae biomass. Additionally, the high nitrogen concentrations found in urine can be inhibitive for growth of microorganisms. Cyanobacteria were expected to overcome phosphorus (P) limitation in urine given their ability to store an N-rich polymer called cyanophycin. In this study, it was found that the model cyanobacterium Synechocystis sp. PCC6803 did not experience significant growth inhibition when cultivated in synthetic medium with concentrations of 0.5 g ammonium-N L−1. In the case of urea, no inhibition was observed when having it as sole nitrogen source, but it resulted in chlorosis of the cultures when the process reached stationary phase. Synechocystis was successfully cultivated in a medium with 0.5 g ammonium-N L−1 and a N:P ratio of 276:1, showing the N:P flexibility of this biomass, reaching biomass N:P ratios up to 92:1. Phosphorus starvation resulted in cyanophycin accumulation up to 4%. Dilution of the culture in fresh medium with the addition of 118 mg N L−1 and 1.5 mg P L−1 (N:P of 174:1) resulted in a rapid and transient cyanophycin accumulation up to 11%, after which cyanophycin levels rapidly decreased to 3%.

Psammaceratin A: A Cytotoxic Psammaplysin Dimer Featuring an Unprecedented (2Z,3Z)-2,3-bis(aminomethylene)succinamide Backbone from the Red Sea Sponge Pseudoceratina arabica

Bioassay-guided partition of the extract of the Red Sea sponge Pseudoceratina arabica and HPLC purification of the active fraction gave a psammaplysin dimer, psammaceratin (1), along with psammaplysin A (2). The dimer comprises two units of psammaplysin A (2) connected via the terminal amines with an unprecedented (2Z,3Z)-2,3-bis(aminomethylene)succinamide moiety, and it represents the first dimer to be identified among the psammaplysin family. Data from 1D- and 2D-NMR and HRMS supported the chemical structures of the compounds. Psammaceratin A (1) and psammaplysin A (2) exhibited significant growth inhibition of HCT 116, HeLa, and MBA-MB-231 cells down to 3.1 mM.

Antitumor Effects of Combining Docetaxel (Taxotere) with the Antivascular Action of Ultrasound Stimulated Microbubbles

Ultrasound stimulated microbubbles (USMB) are being investigated for their potential to promote the uptake of anticancer agents into tumor tissue by exploiting their ability to enhance microvascular permeability. At sufficiently high ultrasound transmit amplitudes it has also recently been shown that USMB treatments can, on their own, induce vascular damage, shutdown blood flow, and inhibit tumor growth. The objective of this study is to examine the antitumor effects of ‘antivascular’ USMB treatments in conjunction with chemotherapy, which differs from previous work which has sought to enhance drug uptake with USMBs by increasing vascular permeability. Conceptually this is a strategy similar to combining vascular disrupting agents with a chemotherapy, and we have selected the taxane docetaxel (Taxotere) for evaluating this approach as it has previously been shown to have potent antitumor effects when combined with small molecule vascular disrupting agents. Experiments were conducted on PC3 tumors implanted in athymic mice. USMB treatments were performed at a frequency of 1 MHz employing sequences of 50 ms bursts (0.00024 duty cycle) at 1.65 MPa. USMB treatments were administered on a weekly basis for 4 weeks with docetaxel (DTX) being given intravenously at a dose level of 5 mg/kg. The USMB treatments, either alone or in combination with DTX, induced an acute reduction in tumor perfusion which was accompanied at the 24 hour point by significantly enhanced necrosis and apoptosis. Longitudinal experiments showed a modest prolongation in survival but no significant growth inhibition occurred in DTX–only and USMB-only treatment groups relative to control tumors. The combined USMB-DTX treatment group produced tumor shrinkage in weeks 4–6, and significant growth inhibition and survival prolongation relative to the control (p<0.001), USMB-only (p<0.01) and DTX-only treatment groups (p<0.01). These results suggest the potential of enhancing the antitumor activity of docetaxel by combining it with antivascular USMB effects.

Antitumor Effects of Combining Docetaxel (Taxotere) with the Antivascular Action of Ultrasound Stimulated Microbubbles

Ultrasound stimulated microbubbles (USMB) are being investigated for their potential to promote the uptake of anticancer agents into tumor tissue by exploiting their ability to enhance microvascular permeability. At sufficiently high ultrasound transmit amplitudes it has also recently been shown that USMB treatments can, on their own, induce vascular damage, shutdown blood flow, and inhibit tumor growth. The objective of this study is to examine the antitumor effects of ‘antivascular’ USMB treatments in conjunction with chemotherapy, which differs from previous work which has sought to enhance drug uptake with USMBs by increasing vascular permeability. Conceptually this is a strategy similar to combining vascular disrupting agents with a chemotherapy, and we have selected the taxane docetaxel (Taxotere) for evaluating this approach as it has previously been shown to have potent antitumor effects when combined with small molecule vascular disrupting agents. Experiments were conducted on PC3 tumors implanted in athymic mice. USMB treatments were performed at a frequency of 1 MHz employing sequences of 50 ms bursts (0.00024 duty cycle) at 1.65 MPa. USMB treatments were administered on a weekly basis for 4 weeks with docetaxel (DTX) being given intravenously at a dose level of 5 mg/kg. The USMB treatments, either alone or in combination with DTX, induced an acute reduction in tumor perfusion which was accompanied at the 24 hour point by significantly enhanced necrosis and apoptosis. Longitudinal experiments showed a modest prolongation in survival but no significant growth inhibition occurred in DTX–only and USMB-only treatment groups relative to control tumors. The combined USMB-DTX treatment group produced tumor shrinkage in weeks 4–6, and significant growth inhibition and survival prolongation relative to the control (p<0.001), USMB-only (p<0.01) and DTX-only treatment groups (p<0.01). These results suggest the potential of enhancing the antitumor activity of docetaxel by combining it with antivascular USMB effects.

Characterization of the Skin Cultivable Microbiota Composition of the Frog Pelophylax perezi Inhabiting Different Environments

Microorganisms that live in association with amphibian skin can play important roles in protecting their host. Within the scenarios of global change, it is important to understand how environmental disturbances, namely, metal pollution, can affect this microbiota. The aim of this study is to recognize core bacteria in the skin cultivable microbiota of the Perez frog (Pelophylax perezi) that are preserved regardless of the environmental conditions in which the frogs live. The characterization of these isolates revealed characteristics that can support their contributions to the ability of frogs to use metal impacted environments. Frog’s skin swabs were collected from P. perezi populations that inhabit a metal-polluted site and three reference (non-metal polluted) sites. Bacterial strains were isolated, identified, and subjected to an acid mine drainage tolerance (AMD) test, collected upstream from a site heavily contaminated with metals, and tested to produce extracellular polymeric substances (exopolysaccharide, EPS). All frog populations had Acinetobacter in their cutaneous cultivable microbiota. Significant growth inhibition was observed in all bacterial isolates exposed to 75% of AMD. EPS production was considered a characteristic of several isolates. The data obtained is a preliminary step but crucial to sustain that the cultivable microbiota is a mechanism for protecting frogs against environmental contamination.

Serine-Arginine Protein Kinase 1 Regulates Ebola Virus Transcription

ABSTRACT Ebola virus (EBOV) causes a severe and often fatal disease for which no approved vaccines or antivirals are currently available. EBOV VP30 has been described as a viral phosphoprotein, and nonphosphorylated VP30 is essential and sufficient to support secondary transcription in an EBOV-specific minigenome system; however, phosphorylatable serine residues near the N terminus of VP30 are required to support primary viral transcription as well as the reinitiation of VP30-mediated transcription at internal EBOV genes. While the dephosphorylation of VP30 by the cellular phosphatase PP2A was found to be mediated by nucleoprotein, the VP30-specific kinases and the role of phosphorylation remain unknown. Here, we report that serine-arginine protein kinase 1 (SRPK1) and SRPK2 phosphorylate serine 29 of VP30, which is located in an N-terminal R26xxS29 motif. Interaction with VP30 via the R26xxS29 motif recruits SRPK1 into EBOV-induced inclusion bodies, the sites of viral RNA synthesis, and an inhibitor of SRPK1/SRPK2 downregulates primary viral transcription. When the SRPK1 recognition motif of VP30 was mutated in a recombinant EBOV, virus replication was severely impaired. It is presumed that the interplay between SRPK1 and PP2A in the EBOV inclusions provides a comprehensive regulatory circuit to ensure the activity of VP30 in EBOV transcription. Thus, the identification of SRPK1 is an important mosaic stone that completes our picture of the players involved in Ebola virus transcription regulation. IMPORTANCE The largest Ebola virus (EBOV) epidemic in West Africa ever caused more than 28,000 cases and 11,000 deaths, and the current EBOV epidemic in the Democratic Republic of the Congo continues, with more than 3,000 cases to date. Therefore, it is essential to develop antivirals against EBOV. Recently, an inhibitor of the cellular phosphatase PP2A-mediated dephosphorylation of the EBOV transcription factor VP30 has been shown to suppress the spread of Ebola virus. Here, we identified the protein kinase SRPK1 as a VP30-specific kinase that phosphorylates serine 29, the same residue that is dephosphorylated by PP2A. SRPK1-mediated phosphorylation of serine 29 enabled primary viral transcription. Mutation of the SRPK1 recognition motif in VP30 resulted in significant growth inhibition of EBOV. Similarly, elevation of the phosphorylation status of serine 29 by overexpression of SRPK1 inhibited EBOV growth, highlighting the importance of reversible phosphorylation of VP30 as a potential therapeutic target.

Design, Synthesis, Molecular Modelling and Anticancer Activities of New Fused Phenanthrolines

Three series of fused pyrrolophenanthroline derivatives were designed as analogues of phenstatin and synthesized in two steps starting with 1,7-phenanthroline, 4,7-phenanthroline and 1,10-phenanthroline, respectively. Two (Compounds 8a and 11c) of the four compounds tested against a panel of sixty human cancer cell lines of the National Cancer Institute (NCI) exhibited significant growth inhibition activity on several cell lines. Compound 11c showed a broad spectrum in terms of antiproliferative efficacy with GI50 values in the range of 0.296 to 250 μM. Molecular docking studies indicated that Compounds 8a and 11c are accommodated in the colchicine binding site of tubulin in two different ways.

Phenylethynylbenzyl-Modified Biguanides Inhibit Pancreatic Cancer Tumor Growth

We present the design and synthesis of a small library of substituted biguanidium salts and their capacity to inhibit the growth/viability of pancreatic cancer cells. We first present their in vitro and membrane activity, before we address their mechanism of action in living cells and in vivo activity. We show that phenylethynyl biguanidium salts possess higher ability to cross hydrophobic barriers, improved mitochondrial accumulation and anticancer activity. Mechanistically, the most active compound 1b, like metformin, decreases the NAD+/NADH ratio and mitochondrial respiration, but at 800-fold lower concentration. In vivo studies with, the most active, compound 1b show a significant growth inhibition of pancreatic cancer xenografts in mice, while biguanides currently in clinical trials had no activity.

Anti-Blastocystis Activity In Vitro of Egyptian Herbal Extracts (Family: Asteraceae) with Emphasis on Artemisia judaica

Achillea fragrantissima (Forssk.) Sch. Bip. (known as Qaysoom), Echinops spinosus L. (known as Shoak Elgamal) and Artemisia judaica L. (known Shih Baladi) are members of the Asteraceae family known for their traditional medical use in Egypt. The ethanol extracts of these plants were evaluated for their efficacy against a protozoan parasite (Blastocystis). Two different molecular subtypes of Blastocystis were used (ST1 and ST3). Significant growth inhibition of Blastocystis was observed when exposed to both A. judaica (99.3%) and A. fragrantissima (95.6%) with minimal inhibitory concentration (MIC90) at 2000 µg/mL. Under the effect of the extracts, changes in Blastocystis morphology were noted, with the complete destruction of Blastocystis forms after 72 h with the dose of 4000 µg/mL. Different subtypes displayed different responses to the herbal extracts tested. ST1 exhibited significantly different responses to the herbal extracts compared to ST3. A. judaica was selected as the herb of choice considering all of its variables and because of its effective action against Blastocystis. It was then exposed to further fractionation and observation of its effect on ST1 and ST3. Solvent portioned fractions (dichloromethane (DCM), ethyl acetate (EtOAc) and n-hexane) in A. judaica were found to be the potent active fractions against both of the Blastocystis subtypes used.