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Anaerobic digestion is the most successful bioenergy technology worldwide with, at its core, undefined microbial communities that have poorly understood dynamics. Here, we investigated the relationships of bacterial community structure (>400,000 16S rRNA gene sequences for 112 samples) with function (i.e., bioreactor performance) and environment (i.e., operating conditions) in a yearlong monthly time series of nine full-scale bioreactor facilities treating brewery wastewater (>20,000 measurements). Each of the nine facilities had a unique community structure with an unprecedented level of stability. Using machine learning, we identified a small subset of operational taxonomic units (OTUs; 145 out of 4,962), which predicted the location of the facility of origin for almost every sample (96.4% accuracy). Of these 145 OTUs, syntrophic bacteria were systematically overrepresented, demonstrating that syntrophs rebounded following disturbances. This indicates that resilience, rather than dynamic competition, played an important role in maintaining the necessary syntrophic populations. In addition, we explained the observed phylogenetic differences between all samples on the basis of a subset of environmental gradients (using constrained ordination) and found stronger relationships between community structure and its function rather than its environment. These relationships were strongest for two performance variables--methanogenic activity and substrate removal efficiency--both of which were also affected by microbial ecology because these variables were correlated with community evenness (at any given time) and variability in phylogenetic structure (over time), respectively. Thus, we quantified relationships between community structure and function, which opens the door to engineer communities with superior functions.

Objective: To determine the door to thrombolysis time of patients who presented to the Adult Priority Care Facility of the Eric Williams Medical Sciences Complex from February 1-May 31, 2008., Method: The patients who presented to the Adult Priority Care Facility of the Eric Williams Medical Sciences Complex with cardiac type chest pain and ST segment elevation that met the international criteria and had positive troponin test were interviewed and their notes reviewed to obtain the relevant information., Results: Fifty-one patients were treated with ST segment elevation myocardial infarctions; 78.4% were thrombolysed. Patients were: 59.75 years old, 68.6% male and 66.7% were of East Indian extraction The average time to thrombolysis was 5 hours and 31 minutes from the onset of chest pain. The average door to thrombolysis time was 2 hours and 7 minutes with 20% of patients having a door to thrombolysis time of 30 minutes. The time to thrombolysis from the onset of chest pain and the door to thrombolysis times were adversely affected by the health facility to which the patient first presented, Conclusion: The majority of patients presented within the thrombolysis window. Early recognition of symptoms of myocardial infarction and arrival at a healthcare facility is not being achieved by the majority of patients. The systems that are responsible for the transport, triage and treatment of patients who present with chest pain are inadequate and require urgent review and overhaul to achieve the goals outlined by the American Heart Association and the American College of Cardiologist.

Anaerobic digestion of brewery wastewater solids in the form of primary sludge was investigated for its potential as a source of energy (methane). We operated a low-rate (hydraulic retention time (HRT)=solids retention time (SRT)) continuously stirred anaerobic digester (CSAD) and a high-rate (SRT>HRT) anaerobic sequencing batch reactor (ASBR) in parallel for 250 days. We found that high-rate anaerobic digestion was beneficial for solids-rich waste flows even during a long-term operating period that included a shock load of nonbiodegradable total solids. The ASBR biomass achieved a higher specific methanogenic activity compared to the CSAD biomass (0.257+/-0.043 vs. 0.088+/-0.008 g CH(4)-COD g(-1)VSS d(-1)), which aided in stability during the shock load with total solids. The methane yield for the ASBR was 40-34% higher than for the CSAD (0.306 vs. 0.219 l CH(4)g VS(-1) fed for days 1-183 and 0.174 vs. 0.130 l CH(4)g VS(-1) fed for days 184-250, respectively). Finally, we operated an ASBR for an additional 295 days to evaluate the effect of temperature variation on system stability. A stable performance was achieved between the operating temperatures of 22-41 degrees C., ((c) 2010 Elsevier Ltd. All rights reserved.)

1. The gigaseal voltage-clamp technique was used to record responses of hamster taste receptor cells to synthetic sweeteners and cyclic nucleotides. Voltage-dependent currents and steady-state currents were monitored during bath exchanges of saccharin, two high-potency sweeteners, 8-chlorophenylthio-adenosine 3',5'-cyclic monophosphate (8cpt-cAMP), and dibutyryl-guanosine 3',5'-cyclic monophosphate (db-cGMP). 2. Of the 237 fungiform taste cells studied, only one in eight was sweet responsive. Outward currents, both voltage-dependent and resting, were reduced by all of the sweeteners tested in sweet-responsive taste cells, whereas these currents were unaffected by sweeteners in sweet-unresponsive taste cells. 3. In every sweet-responsive cell tested, 8cpt-cAMP and db-cGMP mimicked the response to the sweeteners, but neither nucleotide elicited responses in sweet-unresponsive cells. Thus there was a one-to-one correlation between sweet responsivity and cyclic nucleotide responsivity. 4. Sweet responses showed cross adaptation with cyclic nucleotide responses. This indicates that the same ion channel is modulated by sweeteners and cyclic nucleotides. 5. The sweetener- and cyclic nucleotide-blocked current had an apparent reversal potential of -50 mV, which was close to the potassium reversal potential in these experiments. In addition, there was no effect of sweeteners and cyclic nucleotides in the presence of the K+ channel blocker tetraethylammonium bromide (TEA). These data suggest that block of a resting, TEA-sensitive K+ current is the final common step leading to taste cell depolarization during sweet transduction. 6. These data, together with data from a previous study (Cummings et al. 1993), suggest that both synthetic sweeteners and sucrose utilize second-messenger pathways that block a resting K+ conductance to depolarize the taste cell membrane.

1. Physiological and behavioral responses to artificial sweeteners, natural sweeteners, and cyclic nucleotides were assessed using two techniques. An extracellular "in situ" technique recorded action potentials from fungiform taste buds and the two-bottle preference test measured behavioral preferences for the different sweeteners. 2. Two high-potency sweeteners, NC-00274-01 (NC01) and NC-00044-AA (NCAA), were preferred over water at micromolar concentrations. Saccharin and sucrose were likewise preferred, but at millimolar concentrations. 3. Bursts of action currents were elicited by sucrose at 200 mM, saccharin at 20 mM, and NCAA at 0.1 mM. A concentration-response curve for the high-potency sweetener NC01 revealed a threshold concentration of 1 microM and a saturation concentration of 100 microM. No responses were elicited by aspartame. 4. The responses to different sweeteners adapted rapidly at saturating concentrations. With NC01, adaptation was concentration dependent: at threshold the response adapted very slowly if at all. Adaptation increased with increasing concentration. 5. Membrane-permeant analogues of adenosine 3',5'-cyclic monophosphate and guanosine 3',5'-cyclic monophosphate mimicked sweeteners in their ability to elicit a response. This occurred with high fidelity: nearly every taste bud that responded to sweeteners also responded to the nucleotides and every sweet-unresponsive taste bud was nucleotide unresponsive. 6. The sweet responses and nucleotide responses occurred in the absence of permeant apical cations and were not enhanced nor diminished by the presence of such cations. Amiloride had no effect on the sweet response.

The apically restricted, voltage-dependent K+ conductance of Necturus taste receptor cells was studied using cell-attached, inside-out and outside-out configurations of the patch-clamp recording technique. Patches from the apical membrane typically contained many channels with unitary conductances ranging from 30 to 175 pS in symmetrical K+ solutions. Channel density was so high that unitary currents could be resolved only at negative voltages; at positive voltages patch recordings resembled whole-cell recordings. These multi-channel patches had a small but significant resting conductance that was strongly activated by depolarization. Patch current was highly K+ selective, with a PK/PNa ratio of 28. Patches containing single K+ channels were obtained by allowing the apical membrane to redistribute into the basolateral membrane with time. Two types of K+ channels were observed in isolation. Ca(2+)-dependent channels of large conductance (135-175 pS) were activated in cell-attached patches by strong depolarization, with a half-activation voltage of approximately -10 mV. An ATP-blocked K+ channel of 100 pS was activated in cell-attached patches by weak depolarization, with a half-activation voltage of approximately -47 mV. All apical K+ channels were blocked by the sour taste stimulus citric acid directly applied to outside-out and perfused cell-attached patches. The bitter stimulus quinine also blocked all channels when applied directly by altering channel gating to reduce the open probability. When quinine was applied extracellularly only to the membrane outside the patch pipette and also to inside-out patches, it produced a flickery block. Thus, sour and bitter taste stimuli appear to block the same apical K+ channels via different mechanisms to produce depolarizing receptor potentials.

The first interaction of taste stimuli with lingual chemoreceptors occurs on the apical membrane of taste cells, since only that portion is exposed to the oral cavity. To gain better insight into this interaction, we examined the pore region of taste buds in Necturus maculosus with scanning electron microscopy (SEM), transmission electron microscopy, and high-voltage electron microscopy. SEM of the pore reveals a patchwork distribution of three morphologically distinct types of apical specializations: long and branched (LB) microvilli, short and unbranched (SU) microvilli, and bundles of stereocilia. As demonstrated in thin and thick sections, LB microvilli are specializations of dark cells, SU microvilli are the apical specializations of light cells, and stereocilia arise from a cell that has the cytoplasmic markers characteristic of light cells. When left in place, the pore mucus completely covers the SU microvilli and partially covers the LB microvilli. However, stereocilia project above the surface and thus are highly exposed to taste stimuli in the oral cavity. These three morphologically distinct types of apical specializations may reveal functional differences among taste cells. The initial interaction between chemical stimulus and taste cell, and possibly chemoreceptor specificity itself, may be influenced by the morphology of the apical ending.