Biological hydrogen production: molecular and electrolytic perspectives.

Exploration of renewable energy sources is an imperative task in order to replace fossil fuels and to diminish atmospheric pollution. Hydrogen is considered one of the most promising fuels for the future and implores further investigation to find eco-friendly ways toward viable production. Expansive processes like electrolysis and fossil fuels are currently being used to produce hydrogen. Biological hydrogen production (BHP) displays recyclable and economical traits, and is thus imperative for hydrogen economy. Three basic modes of BHP were investigated, including bio photolysis, photo fermentation and dark fermentation. Photosynthetic microorganisms could readily serve as powerhouses to successively produce this type of energy. Cyanobacteria, blue green algae (bio photolysis) and some purple non-sulfur bacteria (Photo fermentation) utilize solar energy and produce hydrogen during their metabolic processes. Ionic species, including hydrogen (H+) and electrons (e-) are combined into hydrogen gas (H2), with the use of special enzymes called hydrogenases in the case of bio photolysis, and nitrogenases catalyze the formation of hydrogen in the case of photo fermentation. Nevertheless, oxygen sensitivity of these enzymes is a drawback for bio photolysis and photo fermentation, whereas, the amount of hydrogen per unit substrate produced appears insufficient for dark fermentation. This review focuses on innovative advances in the bioprocess research, genetic engineering and bioprocess technologies such as microbial fuel cell technology, in developing bio hydrogen production.

Rhodococcus electrodiphilus sp. nov., a marine electro active actinobacterium isolated from coral reef.

An electrogenic bacterium was isolated from a marine coral, designated as strain JC435T and its taxonomic status examined by using a polyphasic approach. Results from the 16S rRNA gene sequence study showed that the isolate belonged to the genus Rhodococcus and formed a cluster with Rhodococcus ruber KCTC 9806T (99.5 % 16S rRNA gene sequence similarity) and Rhodococcus aetherivorans JCM 14343T (99.3 %), respectively. Genome relatedness based on DNA-DNA hybridization to the type strains of closest-related species was less than 30 % and the ΔTm of >7 °C, suggesting that strain represents a new species of the genus Rhodococcus. The major fatty acids were C16 : 0, C18 : 1ω9c, C18 : 010-methyl and C16 : 1ω6c and/or C16 : 1ω7c. The polar lipids of strain JC435T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside, phosphatidylinositol, three unknown phospholipids and an unknown amino lipid. The major isoprenoid quinone was MK-8(H2), with 8 % of MK-7(H2) and 2 % of MK-9(H2) as minor components. Whole-cell hydrolysates contained meso-diaminopimelic acid, arabinose and galactose as the diagnostic diamino acid and sugars. Mycolic acids were detected. The genomic DNA G+C content of strain JC435T was 69.8 mol%. On the basis of phylogenetic genotypic, physiological and chemotaxonomic analysis, strain JC435T is considered to represent a novel species of the genus Rhodococcus for which the name Rhodococcuselectrodiphilus sp. nov. is proposed. The type strain is JC435T (=KCTC 39856T=LMG 29881T=MCC 3659T).

Comparative metabolomic studies of Alkanivorax xenomutans showing differential power output in a three chambered microbial fuel cell.

Metabolomic study of electrogenic bacteria is a necessity to understand the extent of complex organic matter degradation and to invent new co-culture techniques to achieve complete degradation. In this study, we have subjected Alkanivorax xenomutans (KCTC 23751T; NBRC 108843T), a bacterium capable for biodegradation of complex hydrocarbons, to oxic and anoxic conditions in a three chambered microbial fuel cell. In an attempt to understand the molecular mechanisms during the electrogenic processes of A. xenomutans, intra cellular (endo metabolome or the fingerprint) and exo metabolome (extracellular metabolome or the foot print) were analyzed under oxic and anoxic conditions, using FTIR and GC-MS. Interpretation of the data revealed higher number of metabolites in the anoxic fraction as compared to oxic fraction. In addition, expression of putative metabolites that influence electron transfer like flavins, fumarate and quinones were found to be predominant in the organisms when grown in anoxic conditions. Hence, the presence of anoxic conditions governed the electrogenic bacteria to produce enhanced power output by modulating differential metabolomic profiling, compared to the culture grown in oxic conditions.

Oral administration of iron-saturated bovine lactoferrin-loaded ceramic nanocapsules for breast cancer therapy and influence on iron and calcium metabolism.

We determined the anticancer efficacy and internalization mechanism of our polymeric-ceramic nanoparticle system (calcium phosphate nanocores, enclosed in biodegradable polymers chitosan and alginate nanocapsules/nanocarriers [ACSC NCs]) loaded with iron-saturated bovine lactoferrin (Fe-bLf) in a breast cancer xenograft model. ACSC-Fe-bLf NCs with an overall size of 322±27.2 nm were synthesized. In vitro internalization and anticancer efficacy were evaluated in the MDA-MB-231 cells using multicellular tumor spheroids, CyQUANT and MTT assays. These NCs were orally delivered in a breast cancer xenograft mice model, and their internalization, cytotoxicity, biodistribution, and anticancer efficacy were evaluated. Chitosan-coated calcium phosphate Fe-bLf NCs effectively (59%, P≤0.005) internalized in a 1-hour period using clathrin-mediated endocytosis (P≤0.05) and energy-mediated pathways (P≤0.05) for internalization; 3.3 mg/mL of ACSC-Fe-bLf NCs completely disintegrated (~130-fold reduction, P≤0.0005) the tumor spheroids in 72 hours and 96 hours. The IC50 values determined for ACSC-Fe-bLf NCs were 1.69 mg/mL at 10 hours and 1.62 mg/mL after 20 hours. We found that Fe-bLf-NCs effectively (P≤0.05) decreased the tumor size (4.8-fold) compared to the void NCs diet and prevented tumor recurrence when compared to intraperitoneal injection of Taxol and Doxorubicin. Receptor gene expression and micro-RNA analysis confirmed upregulation of low-density lipoprotein receptor and transferrin receptor (liver, intestine, and brain). Several micro-RNAs responsible for iron metabolism upregulated with NCs were identified. Taken together, orally delivered Fe-bLf NCs offer enhanced antitumor activity in breast cancer by internalizing via low-density lipoprotein receptor and transferrin receptor and regulating the micro-RNA expression. These NCs also restored the body iron and calcium levels and increased the hematologic counts.

RNA Interference Using c-Myc-Conjugated Nanoparticles Suppresses Breast and Colorectal Cancer Models.

In this article, we report the development and preclinical validation of combinatorial therapy for treatment of cancers using RNA interference (RNAi). RNAi technology is an attractive approach to silence genes responsible for disease onset and progression. Currently, the critical challenge facing the clinical success of RNAi technology is in the difficulty of delivery of RNAi inducers, due to low transfection efficiency, difficulties of integration into host DNA and unstable expression. Using the macromolecule polyglycidal methacrylate (PGMA) as a platform to graft multiple polyethyleneimine (PEI) chains, we demonstrate effective delivery of small oligos (anti-miRs and mimics) and larger DNAs (encoding shRNAs) in a wide variety of cancer cell lines by successful silencing/activation of their respective target genes. Furthermore, the effectiveness of this therapy was validated for in vivo tumor suppression using two transgenic mouse models; first, tumor growth arrest and increased animal survival was seen in mice bearing Brca2/p53-mutant mammary tumors following daily intratumoral treatment with nanoparticles conjugated to c-Myc shRNA. Second, oral delivery of the conjugate to an Apc-deficient crypt progenitor colon cancer model increased animal survival and returned intestinal tissue to a non-wnt-deregulated state. This study demonstrates, through careful design of nonviral nanoparticles and appropriate selection of therapeutic gene targets, that RNAi technology can be made an affordable and amenable therapy for cancer.

Fe-bLf nanoformulation targets survivin to kill colon cancer stem cells and maintains absorption of iron, calcium and zinc.

AIM: To validate the anticancer efficacy of alginate-enclosed, chitosan-conjugated, calcium phosphate, iron-saturated bovine lactoferrin (Fe-bLf) nanocarriers/nanocapsules (NCs) with improved sustained release and ability to induce apoptosis by downregulating survivin, as well as cancer stem cells. MATERIALS & METHODS: The stability, nanotoxicity of the modified nanoformulation was evaluated and their anticancer efficacy was re-examined. Their mechanism of internalization was studied and we identified the role of various miRNAs in absorption of these NCs/iron in various body parts of mice. We determined the effect of these NCs on survivin, stem cell markers, red blood cell count, iron, calcium and zinc concentration in mice, determined the antiangiogenic properties of these NCs and studied their effect on cancer stem-like cells. RESULTS: Spherical NCs (396.1 ± 27.2 nm) exceedingly reduced viability of Caco-2 cells (32 ± 2.83%). The NCs also showed effective internalization and reduction of cancer stem cell markers in triple-positive CD133, survivin and CD44 cancer stem-like cells. Mice treated with the NCs showed no nanotoxicity and did not develop any tumors in xenograft colon cancer models. We found that the serum iron, zinc and calcium absorption were increased. DMT1, LRP, transferrin and lactoferrin receptors were responsible for internalization of the NCs. Different miRNAs were responsible for iron regulation in different organs. Interestingly, NCs inhibited survivin and its different isoforms. CONCLUSION: Our results confirmed that NCs internalized and changed the expression of selected miRNAs that further enhanced their uptake. The NCs activated both extrinsic, as well as intrinsic apoptotic pathways to induce apoptosis by targeting survivin in cancer cells and cancer stem cells, without inducing any nonspecific nanotoxicity. Apart from inhibiting angiogenesis and stem cell markers, NCs also maintained iron and calcium levels.

OncomiRdbB: a comprehensive database of microRNAs and their targets in breast cancer.

BACKGROUND: Given the estimate that 30% of our genes are controlled by microRNAs, it is essential that we understand the precise relationship between microRNAs and their targets. OncomiRs are microRNAs (miRNAs) that have been frequently shown to be deregulated in cancer. However, although several oncomiRs have been identified and characterized, there is as yet no comprehensive compilation of this data which has rendered it underutilized by cancer biologists. There is therefore an unmet need in generating bioinformatic platforms to speed the identification of novel therapeutic targets. DESCRIPTION: We describe here OncomiRdbB, a comprehensive database of oncomiRs mined from different existing databases for mouse and humans along with novel oncomiRs that we have validated in human breast cancer samples. The database also lists their respective predicted targets, identified using miRanda, along with their IDs, sequences, chromosome location and detailed description. This database facilitates querying by search strings including microRNA name, sequence, accession number, target genes and organisms. The microRNA networks and their hubs with respective targets at 3'UTR, 5'UTR and exons of different pathway genes were also deciphered using the 'R' algorithm. CONCLUSION: OncomiRdbB is a comprehensive and integrated database of oncomiRs and their targets in breast cancer with multiple query options which will help enhance both understanding of the biology of breast cancer and the development of new and innovative microRNA based diagnostic tools and targets of therapeutic significance. OncomiRdbB is freely available for download through the URL link http://tdb.ccmb.res.in/OncomiRdbB/index.htm.

Novel alginate-enclosed chitosan-calcium phosphate-loaded iron-saturated bovine lactoferrin nanocarriers for oral delivery in colon cancer therapy.

AIM: To develop polymeric-ceramic nanocarriers (NCs) in order to achieve oral delivery of the anticancer neutraceutical iron-saturated bovine lactoferrin (Fe-bLf) protein. MATERIALS & METHODS: Fe-bLf or paclitaxel (Taxol®) were adsorbed onto calcium phosphate nanocores, enclosed in biodegradable polymers chitosan and alginate. The Fe-bLf or Taxol-loaded NCs indicated as AEC-CP-Fe-bLf or AEC-CP-Taxol NCs, respectively, were made by combination of ionic gelation and nanoprecipitation. Size distribution, morphology, internalization and release profiles of the NCs were studied along with evaluation of in vitro and in vivo anticancer activities and compared with paclitaxel. RESULTS: AEC-CP-Fe-bLf NCs obtained spherical morphology and showed enhanced endocytosis, transcytosis and anticancer activity in Caco-2 cells in vitro. AEC-CP-Fe-bLf NCs were supplemented in an AIN 93G diet and fed to mice in both prevention and treatment human xenograft colon cancer models. AEC-CP-Fe-bLf NCs were found to be highly significantly effective when given orally, as a pretreatment, 1 week before Caco-2 cell injections. None of the mice from the AEC-CP-Fe-bLf NC-fed group developed tumors or showed any signs of toxicity, while the mice fed the control AIN 93G diet showed normal tumor growth. Fe-bLf or Taxol, when given orally in a diet as nanoformulations post-tumor development, showed a significant regression in the tumor size with complete inhibition of tumor growth later, while intratumoral injection of Taxol just delayed the growth of tumors. The pharmacokinetic and bioavailability studies indicated that nanoformulated Fe-bLf was predominantly present on tumor cells compared to non-nanoformulated Fe-bLf. Fe-bLf-loaded NCs were found to help in absorption of iron and thus may have utility in enhancing the iron uptake during iron deficiency without interfering with the absorption of calcium. CONCLUSION: With the promising results of our study, the future potential of NC-loaded Fe-bLf in chemoprevention and in the treatment of human colon cancer, deserves further investigation for translational research and preclinical studies of other malignancies.

Effect of selenium-saturated bovine lactoferrin (Se-bLF) on antioxidant enzyme activities in human gut epithelial cells under oxidative stress.

Cancer and many chronic inflammatory diseases are associated with increased amounts of reactive oxygen species (ROS). The potential cellular and tissue damage created by ROS has significant impact on many disease and cancer states and natural therapeutics are becoming essential in regulating altered redox states. We have shown recently that iron content is a critical determinant in the antitumour activity of bovine milk lactoferrin (bLF). We found that 100% iron-saturated bLF (Fe-bLF) acts as a potent natural adjuvant and fortifying agent for augmenting cancer chemotherapy and thus has a broad utility in the treatment of cancer. Furthermore, we also studied the effects of iron saturated bLF's ability as an antioxidant in the human epithelial colon cancer cell line HT29, giving insights into the potential of bLF in its different states. Thus, metal saturated bLF could be implemented as anti-cancer neutraceutical. In this regard, we have recently been able to prepare a selenium (Se) saturated form of bLF, being up to 98% saturated. Therefore, the objectives of this study were to determine how oxidative stress induced by hydrogen peroxide (H2O2) alters antioxidant enzyme activity within HT29 epithelial colon cancer cells, and observe changes in this activity by treatments with different antioxidants ascorbic acid (AA), Apo (iron free)-bLF and selenium (Se)-bLF. The states of all antioxidant enzymes (glutathione peroxidase (GPx), glutathione reductase (GR), glutathione- s-transferase (GsT), catalase and superoxide dismutase (SOD)) demonstrated high levels within untreated HT29 cells compared to the majority of other treatments being used, even prior to H2O2 exposure. All enzymes showed significant alterations in activity when cells were treated with antioxidants AA, Apo-bLF or Se-bLF, with and/or without H2O2 exposure. Obvious indications that the Se content of the bLF potentially interacted with the glutathione (GSH)/GPx/GR/GsT associated redox system could be observed immediately, showing capability of Se-bLF being highly beneficial in helping to maintain a balance between the oxidant/antioxidant systems within cells and tissues, especially in selenium deficient systems. In conclusion, the antioxidative defence activity of Se-bLf, investigated in this study for the first time, shows dynamic adaptations that may allow for essential protection from the imbalanced oxidative conditions. Because of its lack of toxicity and the availability of both selenium and bLF in whole milk, Se-bLF offers a promise for a prospective natural dietary supplement, in addition to being an immune system enhancement, or a potential chemopreventive agent for cancers.

Antiangiogenic therapy using nanotechnological-based delivery system.

Of the many approaches for the treatment of cancer, angiogenesis and the additional promotion of apoptosis in cancer stem cells by using combinatorial therapy is usually the most recommended. There has been increased interest in the use of antiapoptotic and antiangiogenic biomolecules, such as antiangiogenic microRNA, small interfering RNA, inhibitor of apoptosis protein-binding peptides and Von Hippel-Lindau tumor suppressors, as well as targeting ligands, such as aptamers. Therefore, it is tempting to suggest that such molecules could be used for anticancer therapy. As we review here, such exploitation can be achieved by using nanotechnology and RNA-carrying cationic cell-penetrating peptides, for better protection from the enzymatic digestion and enhanced cellular internalization of these biomolecules.

MicroRNA in human cancer and chronic inflammatory diseases.

MicroRNAs (miRNAs) are the non-coding RNAs that act as post-translational regulators to their complimentary messenger RNAs (mRNA). Due to their specific gene silencing property, miRNAs have been implicated in a number of cellular and developmental processes. Also, it has been proposed that a particular set of miRNA spectrum is expressed only in a particular type of tissue. Many interesting findings related to the differential expression of miRNAs in various human diseases including several types of cancers, neurodegenerative diseases and metabolic diseases have been reported. Deregulation of miRNA expression in different types of human diseases and the roles various miRNAs play as tumour suppressors as well as oncogenes, suggest their contribution to cancer and/or in other disease development. These findings have possible implications in the development of diagnostics and/or therapeutics in human malignancies. In this review, we discuss various miRNAs that are differentially expressed in human chronic inflammatory diseases, neurodegenerative diseases, cancer and the further prospective development of miRNA based diagnostics and therapeutics.