Seeking Sunlight: Rapid Phototactic Motility of Filamentous Mat-Forming Cyanobacteria Optimize Photosynthesis and Enhance Carbon Burial in Lake Huron’s Submerged Sinkholes

We studied the motility of filamentous mat-forming cyanobacteria consisting primarily ofOscillatoria-like cells growing under low-light, low-oxygen, and high-sulfur conditions in Lake Huron’s submerged sinkholes using in situ observations, in vitro measurements and time-lapse microscopy. Gliding movement of the cyanobacterial trichomes (100–10,000 μm long filaments, composed of cells ~10 μm wide and ~3 μm tall) revealed individual as well as group-coordinated motility. When placed in a petri dish and dispersed in ground water from the sinkhole, filaments re-aggregated into defined colonies within minutes, then dispersed again. Speed of individual filaments increased with temperature from ~50 μm min-1 or ~15 body lengths min-1 at 10∘C to ~215 μm min-1 or ~70 body lengths min-1 at 35∘C – rates that are rapid relative to non-flagellated/ciliated microbes. Filaments exhibited precise and coordinated positive phototaxis toward pinpoints of light and congregated under the light of foil cutouts. Such light-responsive clusters showed an increase in photosynthetic yield – suggesting phototactic motility aids in light acquisition as well as photosynthesis. Once light source was removed, filaments slowly spread out evenly and re-aggregated, demonstrating coordinated movement through inter-filament communication regardless of light. Pebbles and pieces of broken shells placed upon intact mat were quickly covered by vertically motile filaments within hours and became fully buried in the anoxic sediments over 3–4 diurnal cycles – likely facilitating the preservation of falling debris. Coordinated horizontal and vertical filament motility optimize mat cohesion and dynamics, photosynthetic efficiency and sedimentary carbon burial in modern-day sinkhole habitats that resemble the shallow seas in Earth’s early history. Analogous cyanobacterial motility may have played a key role in the oxygenation of the planet by optimizing photosynthesis while favoring carbon burial

Increased Expression of Interleukin-6 Family Members and Receptors in Urinary Bladder with Cyclophosphamide-Induced Bladder Inflammation in Female Rats

Recent studies suggest that janus-activated kinases–signal transducer and activator of transcription signaling pathways contribute to increased voiding frequency and referred pain of cyclophosphamide (CYP)-induced cystitis in rats. Potential upstream chemical mediator(s) that may be activated by CYP-induced cystitis to stimulate JAK/STAT signaling are not known in detail. In these studies, members of the interleukin (IL)-6 family of cytokines including, leukemia inhibitory factor (LIF), IL-6, and ciliary neurotrophic factor (CNTF) and associated receptors, IL-6 receptor (R) α, LIFR, and gp130 were examined in the urinary bladder in control and CYP-treated rats. Cytokine and receptor transcript and protein expression and distribution were determined in urinary bladder after CYP-induced cystitis using quantitative, real-time polymerase chain reaction (Q-PCR), western blotting, and immunohistochemistry. Acute (4 h; 150 mg/kg; i.p.), intermediate (48 h; 150 mg/kg; i.p.), or chronic (75 mg/kg; i.p., once every 3 days for 10 days) cystitis was induced in adult, female Wistar rats with CYP treatment. Q-PCR analyses revealed significant (p ≤ 0.01) CYP duration- and tissue- (e.g., urothelium, detrusor) dependent increases in LIF, IL-6, IL-6Rα, LIFR, and gp130 mRNA expression. Western blotting demonstrated significant (p ≤ 0.01) increases in IL-6, LIF, and gp130 protein expression in whole urinary bladder with CYP treatment. CYP-induced cystitis significantly (p ≤ 0.01) increased LIF-immunoreactivity (IR) in urothelium, detrusor, and suburothelial plexus whereas increased gp130-IR was only observed in urothelium and detrusor. These studies suggest that IL-6 and LIF may be potential upstream chemical mediators that activate JAK/STAT signaling in urinary bladder pathways

Painful inflammation-induced increase in opioid receptor binding and G-protein coupling in primary afferent neurons

ABSTRACT Opioids mediate their analgesic effects by activating -opioid receptors (MOR) not only within the central nervous system but also on peripheral sensory neurons. The peripheral analgesic effects of opioids are best described under inflammatory conditions (e.g., arthritis). The present study investigated the effects of inflammation on MOR binding and G-protein coupling of full versus partial MOR agonists in dorsal root ganglia (DRG) of primary afferent neurons. Our results show that Freund's complete adjuvant (FCA) unilateral hindpaw inflammation induces a significant up-regulation of MOR binding sites (25 to 47 fmol/mg of protein) on DRG membranes without affecting the affinity of either full or partial MOR agonists. In our immunohistochemical studies, the number of MOR-immunoreactive neurons consistently increased. This increase was mostly caused by small-diameter nociceptive DRG neurons. The full agonist DAMGO induced MOR G-protein coupling in DRG of animals without FCA inflammation (EC 50 ϭ 56 nM; relative E max ϭ 100%). FCA inflammation resulted in significant increases in DAMGO-induced MOR G-protein coupling (EC 50 ϭ 29 nM; relative E max ϭ 145%). The partial agonist buprenorphine hydrochloride (BUP) showed no detectable G-protein coupling in DRG of animals without FCA inflammation; however, partial agonist activity of BUP-induced MOR G-protein coupling was detectable in animals with FCA inflammation (EC 50 ϭ 1.6 nM; relative E max ϭ 82%). In behavioral studies, administration of BUP produced significant antinociception only in inflamed but not in noninflamed paws. These findings show that inflammation causes changes in MOR binding and G-protein coupling in primary afferent neurons. They further underscore the important differences in clinical studies testing peripherally active opioids in inflammatory painful conditions. Opioid analgesia is not mediated exclusively within the central nervous system but also in the periphery. This has been shown in many animal models, including unilateral hindpaw inflammation induced by intraplantar injection of Freund's complete adjuvant (FCA) Materials and Method

Systematically Variable Planktonic Carbon Metabolism Along a Land-To-Lake Gradient in a Great Lakes Coastal Zone

During the summers of 2002–2013, we measured rates of carbon metabolism in surface waters of six sites across a land-to-lake gradient from the upstream end of drowned river-mouth Muskegon Lake (ML) (freshwater estuary) to 19 km offshore in Lake Michigan (LM) (a Great Lake). Despite considerable inter-year variability, the average rates of gross production (GP), respiration (R) and net production (NP) across ML (604 ± 58, 222 ± 22 and 381 ± 52 µg C L−1 day−1, respectively) decreased steeply in the furthest offshore LM site (22 ± 3, 55 ± 17 and −33 ± 15 µg C L−1day−1, respectively). Along this land-to-lake gradient, GP decreased by 96 ± 1%, whereas R only decreased by 75 ± 9%, variably influencing the carbon balance along this coastal zone. All ML sites were consistently net autotrophic (mean GP:R = 2.7), while the furthest offshore LM site was net heterotrophic (mean GP:R = 0.4). Our study suggests that pelagic waters of this Great Lakes coastal estuary are net carbon sinks that transition into net carbon sources offshore. Reactive and dynamic estuarine coastal zones everywhere may contribute similarly to regional and global carbon cycles

Chronicles of hypoxia: Time-series buoy observations reveal annually recurring seasonal basin-wide hypoxia in Muskegon Lake – A Great Lakes estuary

We chronicled the seasonally recurring hypolimnetic hypoxia in Muskegon Lake – a Great Lakes estuary over 3 years, and examined its causes and consequences. Muskegon Lake is a mesotrophic drowned river mouth that drains Michigan\u27s 2nd largest watershed into Lake Michigan. A buoy observatory tracked ecosystem changes in the Muskegon Lake Area of Concern (AOC), gathering vital time-series data on the lake\u27s water quality from early summer through late fall from 2011 to 2013 (www.gvsu.edu/buoy). Observatory-based measurements of dissolved oxygen (DO) tracked the gradual development, intensification and breakdown of hypoxia (mild hypoxia b4 mg DO/L, and severe hypoxia b2 mg DO/L) below the ~6 m thermocline in the lake, occurring in synchrony with changes in temperature and phytoplankton biomass in the water column during July–October. Time-series data suggest that proximal causes of the observed seasonal hypolimnetic DO dynamics are stratified summer water-column, reduced wind-driven mixing, longer summer residence time, episodic intrusions of cold DO-rich nearshore Lake Michigan water, nutrient run off from watershed, and phytoplankton blooms. Additional basin-wide water-column profiling (2011–2012) and ship-based seasonal surveys (2003–2013) confirmed that bottom water hypoxia is an annually recurring lake-wide condition. Volumetric hypolimnetic oxygen demand was high (0.07–0.15 mg DO/Liter/day) and comparable to other temperate eutrophic lakes. Over 3 years of intense monitoring, ~9–24% of Muskegon Lake\u27s volume experienced hypoxia for ~29–85 days/year – with the potential for hypolimnetic habitat degradation and sediment phosphorus release leading to further eutrophication. Thus, time-series observatories can provide penetrating insights into the inner workings of ecosystems and their external drivers

Financial fragmentation and SMEs’ access to finance

This paper focuses on the impact of financial fragmentation on small and medium enterprises (SMEs)’ access to finance. We combine country-level data on financial fragmentation and the ECB’s SAFE (Survey on the Access to Finance of Enterprises) data for 12 European Union (EU) countries over 2009-2016. Our findings indicate that an increase in financial fragmentation not only raises the probability of all firms to be rationed but also to be charged higher loan rates; in addition, it increases the likelihood of borrower discouragement and it impairs firms’ perceptions of the future availability of bank funds. Less creditworthy firms are even more likely to become credit rationed, suggesting a flight to quality effect in lending. However, our study also documents a potential adverse effect of increasing bank market power resulting from greater integration. This suggests that financial integration could impair firms’ financing, if not accompanied by policy initiatives aimed at maintaining an optimal level of competition in the banking sector

Decoupling Between Bacteria and the Surf-zone Diatom Asterionellopsis glacialis at Cassino Beach, Brazil

The surf-zone diatom Asterionellopsis glacialis (Castracane) Round attains extremely high abundances (up to 109 cells l–1) and chl a concentrations (up to 1.5 mg chl a l–1), forming darkbrown patches in Cassino Beach, southern Brazil. Several lines of evidence from this study indicate a decoupling between A. glacialis and heterotrophic bacteria. For instance, despite the high abundance of diatoms, associated high levels of chl a and rates of dissolved organic carbon (DOC) production by A. glacialis, bacterial abundance at Cassino Beach was extremely low (0.03 to 0.7 × 106 cells ml–1) compared to the nearby estuarine waters, adjacent coastal waters and those from the literature. No statistical differences were found between bacterial abundance in- and outside the diatom patches, suggesting that direct association with A. glacialis did not stimulate bacterial growth. Moreover, field and laboratory experiments demonstrated that bacteria take 1 to 4 d to begin growing following the input of A. glacialis cell-free filtrate. Five possible reasons for this decoupling, i.e. (1) viral infection, (2) bacterial grazing, (3) DOC quality, (4) nutrient competition and (5) antibiotic production, are discussed. Because of the decoupling between the surf-zone diatom and heterotrophic bacteria in this high-energy surf-zone ecosystem, a large fraction of A. glacialis primary production is not contemporaneously channeled through the microbial food web. Consequently, much of the surf-zone diatom production may fuel metazoan secondary production in the adjacent nearshore and coastal environment. Copyright Inter-Research 2003, Originally published in Aquatic Microbial Ecology, Vol. 32: 219-228, 2003

Upregulation of vascular endothelial growth factor isoform VEGF-164 and receptors (VEGFR-2, Npn-1, and Npn-2) in rats with cyclophosphamide-induced cystitis

Regulation of the VEGF-VEGF receptor system was examined in the urinary bladder after acute (2–48 h) and chronic (10 days) cyclophosphamide (CYP)-induced cystitis. ELISAs demonstrated significant (P ≤ 0.01) upregulation of VEGF in whole urinary bladder with acute and chronic CYP-induced cystitis; however, the magnitude of increase was greater after acute (2–4 h) cystitis. Immunohistochemistry for VEGF immunoreactivity revealed a significant (P ≤ 0.05) increase in VEGF immunoreactivity in the urothelium, suburothelial vasculature, and detrusor smooth muscle with acute (4 and 48 h) CYP treatment. RT-PCR identified the isoform VEGF-164, the VEGF receptor VEGFR-2, and the VEGF co-receptors neuropilin (Npn)-1 and Npn-2 in the urinary bladder. Quantitative PCR demonstrated upregulation of VEGF-164 transcript with acute and chronic CYP-induced cystitis, but VEGFR-2, Npn-1, and Npn-2 transcripts were upregulated (P ≤ 0.01) in whole bladder only with chronic CYP-induced cystitis. Additional studies demonstrated regulation of VEGF transcript expression in the urinary bladder by nerve growth factor (NGF) in a novel line of NGF-overexpressing mice. These studies demonstrated that urinary bladder inflammation and NGF regulate the VEGF-VEGF receptor system in the urinary bladder. Functional role(s) for the VEGF-VEGF receptor system in urinary bladder inflammation remain to be determined

Benthic Bacterial Diversity in Submerged Sinkhole Ecosystems▿ †

Physicochemical characterization, automated ribosomal intergenic spacer analysis (ARISA) community profiling, and 16S rRNA gene sequencing approaches were used to study bacterial communities inhabiting submerged Lake Huron sinkholes inundated with hypoxic, sulfate-rich groundwater. Photosynthetic cyanobacterial mats on the sediment surface were dominated by Phormidium autumnale, while deeper, organically rich sediments contained diverse and active bacterial communities