Biohydrogen production beyond the Thauer limit by precision design of artificial microbial consortia.

Dark fermentative biohydrogen (H2) production could become a key technology for providing renewable energy. Until now, the H2 yield is restricted to 4 moles of H2 per mole of glucose, referred to as the "Thauer limit". Here we show, that precision design of artificial microbial consortia increased the H2 yield to 5.6 mol mol-1 glucose, 40% higher than the Thauer limit. In addition, the volumetric H2 production rates of our defined artificial consortia are superior compared to any mono-, co- or multi-culture system reported to date. We hope this study to be a major leap forward in the engineering of artificial microbial consortia through precision design and provide a breakthrough in energy science, biotechnology and ecology. Constructing artificial consortia with this drawing-board approach could in future increase volumetric production rates and yields of other bioprocesses. Our artificial consortia engineering blueprint might pave the way for the development of a H2 production bioindustry.

Current status of artemisinin-resistant falciparum malaria in South Asia: a randomized controlled artesunate monotherapy trial in Bangladesh.

OBJECTIVE: Recent reports indicate that first cases of genuine artemisinin resistance have already emerged along the Thai-Cambodian border. The main objective of this trial was to track the potential emergence of artemisinin resistance in Bangladesh, which in terms of drug resistance forms a gateway to the Indian subcontinent. METHODS: We conducted an open-label, randomized, controlled 42-day clinical trial in Southeastern Bangladesh to investigate the potential spread of clinical artemisinin resistance from Southeast Asia. A total of 126 uncomplicated falciparum malaria patients were randomized to one of 3 treatment arms (artesunate monotherapy with 2 or 4 mg/kg/day once daily or quinine plus doxycycline TID for 7 days). Only cases fulfilling a stringent set of criteria were considered as being artemisinin-resistant. FINDINGS: The 28-day and 42-day cure rates in the artesunate monotherapy (2 and 4 mg/kg) and quinine/doxycyline arms were 97.8% (95% confidence interval, CI: 87.8-99.8%), 100% (95% CI: 91.1-100%), and 100% (95% CI: 83.4-100%), respectively. One case of re-infection was seen in the artesunate high dose arm, and a single case of recrudescence was observed in the low dose group on day 26. No differences in median parasite and fever clearance times were found between the 2 artesunate arms (29.8 h and 17.9 h vs. 29.5 h and 19.1 h). Not a single case fulfilled our criteria of artemisinin resistance. Parasite clearance times were considerably shorter and ex vivo results indicate significantly higher susceptibility (50% inhibitory concentration for dihydroartemisinin was 1.10 nM; 95% CI: 0.95-1.28 nM) to artemisinins as compared to SE-Asia. CONCLUSION: There is currently no indication that artemisinin resistance has reached Bangladesh. However, the fact that resistance has recently been reported from nearby Myanmar indicates an urgent need for close monitoring of artemisinin resistance in the region. TRIAL REGISTRATION: ClinicalTrials.gov NCT00639873.

Clinical and functional outcomes of laminoplasty and laminectomy.

OBJECTIVE: Laminoplasty has become a common alternative to laminectomy for cervical spondylotic myelopathy or radiculopathy. The procedures have been compared before, but data on functional recovery are limited. We aim to compare the safety and short-term clinical and functional outcomes of cervical laminoplasty and cervical laminectomy. METHODS: We performed a retrospective analysis of the outcome of 72 patients who had laminoplasty and 49 patients who had laminectomy at our hospital from 1999 to 2005. Patients had cervical spondylotic myelopathy or radiculopathy. All of the patients were similar in age and pre-operative functional status. All patients were assessed pre-operatively and 4 months post-operatively with the Rankin disability score, Glasgow outcome scale and Karnofsky and Nurick scales. RESULTS: Laminoplasty resulted in greater improvement than laminectomy on the Rankin scale (p<0.0001, chi-square test), GOS (p<0.0027, chi-square test) and Karnofsky scores (p<0.01, Wilcoxon test). Nurick scores improved in both groups without a significant difference (p<0.62, Wilcoxon test). The proportion of patients who improved on all scales tended to be greater in the laminoplasty group. Patients spent 1.8 fewer days in the hospital after laminoplasty (p=0.04, Wilcoxon rank-sum test). There was no mortality or permanent morbidity for either procedure. CONCLUSION: Both cervical laminectomy and laminoplasty are safe and effective for the treatment of cervical myelopathy or radiculopathy. Cervical laminoplasty results in a shorter hospital stay and greater functional improvement at 4 months follow-up.

Interplay of Ca2+ and cAMP signaling in the insulin-secreting MIN6 beta-cell line.

Ca2+ and cAMP are important second messengers that regulate multiple cellular processes. Although previous studies have suggested direct interactions between Ca2+ and cAMP signaling pathways, the underlying mechanisms remain unresolved. In particular, direct evidence for Ca2+-regulated cAMP production in living cells is incomplete. Genetically encoded fluorescence resonance energy transfer-based biosensors have made possible real-time imaging of spatial and temporal gradients of intracellular cAMP concentration in single living cells. Here, we used confocal microscopy, fluorescence resonance energy transfer, and insulin-secreting MIN6 cells expressing Epac1-camps, a biosynthetic unimolecular cAMP indicator, to better understand the role of intracellular Ca2+ in cAMP production. We report that depolarization with high external K+, tolbutamide, or glucose caused a rapid increase in cAMP that was dependent on extracellular Ca2+ and inhibited by nitrendipine, a Ca2+ channel blocker, or 2',5'-dideoxyadenosine, a P-site antagonist of transmembrane adenylate cyclases. Stimulation of MIN6 cells with glucose in the presence of tetraethylammonium chloride generated concomitant Ca2+ and cAMP oscillations that were abolished in the absence of extracellular Ca2+ and blocked by 2',5'-dideoxyadenosine or 3-isobutyl-1-methylxanthine, an inhibitor of phosphodiesterase. Simultaneous measurements of Ca2+ and cAMP concentrations with Fura-2 and Epac1-camps, respectively, revealed a close temporal and causal interrelationship between the increases in cytoplasmic Ca2+ and cAMP levels following membrane depolarization. These findings indicate highly coordinated interplay between Ca2+ and cAMP signaling in electrically excitable endocrine cells and suggest that Ca2+-dependent cAMP oscillations are derived from an increase in adenylate cyclase activity and periodic activation and inactivation of cAMP-hydrolyzing phosphodiesterase.