Oxygen and nitrate-dependent regulation of dmsABC operon expression in Escherichia coli: sites for Fnr and NarL protein interactions

BACKGROUND: Escherichia coli can respire anaerobically using dimethyl sulfoxide (DMSO) or trimethylamine-N-oxide (TMAO) as the terminal electron acceptor for anaerobic energy generation. Expression of the dmsABC genes that encode the membrane-associated DMSO/TMAO reductase is positively regulated during anaerobic conditions by the Fnr protein and negatively regulated by the NarL protein when nitrate is present. RESULTS: The regions of dmsA regulatory DNA required for Fnr and NarL interactions in response to anaerobiosis and nitrate, respectively, were examined. Mutations within the Fnr site that deviated from the wild type sequence, TTGATaccgAACAA, or that removed an entire half-site, either impaired or abolished the anaerobic activation of dmsA-lacZ expression. The region for phosphorylated NarL (NarL-phosphate) binding at the dmsA promoter was identified by DNase I and hydroxyl radical footprinting methods. A large 97 bp region that overlaps the Fnr and RNA polymerase recognition sites was protected by NarL-phosphate but not by the non-phosphorylated form of NarL. Hydroxyl radical footprinting analysis confirmed the NarL-phosphate DNase I protections of both dmsA strands and revealed 8–9 protected sites of 3–5 bp occurring at ten bp intervals that are offset by 3 bp in the 3' direction. CONCLUSION: These findings suggest that multiple molecules of phosphorylated NarL bind along one face of the DNA and may interfere with Fnr and/or RNA polymerase interactions at the dmsA regulatory region. The interplay of these transcription factors insures a hierarchical expression of the dmsABC genes when respiration of the preferred electron acceptors, oxygen and nitrate, is not possible

Dendrite growth in selector-root area of single crystal CMSX-4 turbine blades

The single crystal turbine blades made of CMSX-4 nickel-based superalloy were studied. The turbine blades were obtained by the Bridgman technique with withdrawal rate of 5 mm/min. The samples, cut-off from root part of blades and containing the fragment of the selector, were studied. The effect of selector geometry on the dendrites growth and defects formation in the selector-root area of the blade were analyzed. The Laue diffraction, scanning electron microscopy, and X-ray diffraction topography were applied. It was found that, during crystallization of the selector, the dendrite cores, after reaching the surface of mould, may bend, if the angle between dendrite cores and the mould surface was equal to 12 . When the angle was equal to 24 the growth of dendrites has been stopped. It can be stated that the defects, which appeared in the selector were inherited by the root part

Calcium-boron interaction demonstrated by Lemna minor on clay suspensions

This bulletin is a report on Department of Soils research project 92, Minor Soil Elements--P. [2].Digitized 2007 AES.Includes bibliographical references (pages 14-15)

Soil fertility and the quality of seeds

Cover title.Digitized 2007 AES.Includes bibliographical references (page [23])

A High Stellar Obliquity in the WASP-7 Exoplanetary System

We measure a tilt of 86+-6 deg between the sky projections of the rotation axis of the WASP-7 star, and the orbital axis of its close-in giant planet. This measurement is based on observations of the Rossiter-McLaughlin (RM) effect with the Planet Finder Spectrograph on the Magellan II telescope. The result conforms with the previously noted pattern among hot-Jupiter hosts, namely, that the hosts lacking thick convective envelopes have high obliquities. Because the planet's trajectory crosses a wide range of stellar latitudes, observations of the RM effect can in principle reveal the stellar differential rotation profile; however, with the present data the signal of differential rotation could not be detected. The host star is found to exhibit radial-velocity noise (``stellar jitter') with an amplitude of ~30m/s over a timescale of days.Comment: ApJ accepted, 9 pages, 9 figure

Proteomic analyses identify differences between bovine epididymal and ejaculated spermatozoa that contribute to longevity

Sperm are stored for extended periods of time in the epididymis, but upon ejaculation motility is increased and lifespan is decreased. The objective of this study was to identify differences in proteins between epididymis and ejaculated samples that are associated with longevity. Ejaculated semen was collected from mature Angus bulls (n = 9); bulls were slaughtered and epididymal semen was collected. Epididymal and ejaculated semen were centrifuged to separate sperm and fluid. Fluids were removed and sperm pellets were resuspended in a high ionic solution and vortexed to remove loosely attached proteins. Sperm samples were centrifuged, and the supernatant was removed; both fluid and sperm samples were snap frozen in liquid nitrogen and stored at -80 oC. Protein analysis was performed by LCMS/MS. A different group of yearling Angus cross bulls (n = 40) were used for sperm cultures. Ejaculated (n = 20) and epididymal (n = 20) semen were diluted and cultured in a commercial media at pH 5.8, 6.8 and 7.3, at 4 oC. Sperm were evaluated for motility and viability every 24 h until motility was lower than 20%. There was an effect of pH, time and pH by time interaction for motility and viability for both ejaculated and epididymal sperm (P ≤ 0.05). At 216 h of incubation epididymal sperm at pH 7.3 and ejaculated sperm at pH 6.8 reached motility below 20%. A total of 458 unique proteins were identified; 178, 298, 311, and 344 proteins were identified in ejaculated fluid, ejaculated sperm, epididymal fluid and epididymal sperm, respectively. There were 8, 24, 10, and 18 significant KEGG pathways (FDR \u3c0.05) for ejaculated fluid, epididymal fluid, ejaculated sperm, and epididymal sperm, respectively. The metabolic pathway was identified as the most important KEGG pathway; glycolysis/gluconeogenesis, pentose phosphate, and glutathione metabolism pathways were significant among proteins only present in epididymal samples within the metabolic pathway. Other proteins identified that may be related to epididymal sperm\u27s increased longevity were peroxidases and glutathione peroxidases for their antioxidant properties. In summary, energy metabolism in the epididymis appears to be more glycolytic compared to ejaculated and epididymis sperm have a larger number of antioxidants available which may be helping to maintain sperm in a quiescent state. Epididymal sperm remained viable (membrane integrity) longer than ejaculated sperm when cultured at the same pH

Proteomic Analysis of Epididymal and Ejaculated Sperm and Respective Fluids

Study Description: Ejaculated and epididymal semen was collected from mature Angus bulls (n = 9), and then centrifuged to separate sperm and fluid. Fluids were collected and sperm pellets were resuspended in a high ionic solution and vortexed to remove loosely attached proteins. Sperm samples were centrifuged, and the supernatant was collected. Samples collected for protein analysis were snap frozen in liquid nitrogen and stored at -80 ºC. Protein analysis was performed by liquid chromatography with tandem mass spectrometry (LCMS/MS). Yearling Angus cross bulls (n = 40) were used for sperm cultures. Ejaculated (n = 20) and epididymal (n = 20) sperm were collected, diluted and cultured in a commercial media at pH 5.8, 6.8 and 7.3, at 4 ºC and evaluated for motility and viability every 24 h until motility was below 20%. There was an effect of pH, time and pH by time interaction for motility and viability for both ejaculated and epididymal sperm (P ≤ 0.05). At 216 h of incubation epididymal sperm at pH 7.3 and ejaculated sperm at pH 6.8 dropped below 20% motility. Overall, in all samples, a total of 458 unique proteins were identified. It was identified that ejaculated fluid and ejaculated sperm had 178 and 298 proteins, respectively. Also, it was identified that epididymal fluid and epididymal sperm had 311 and 344 proteins, respectively. There were Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways significantly enriched (FDR \u3c 0.05) for ejaculated fluid (n = 8), epididymal fluid (n = 24), ejaculated sperm (n = 10), and epididymal sperm (n = 18). The most important KEGG pathway identified was the metabolic pathway. Within the metabolic pathway the glycolysis/gluconeogenesis, pentose phosphate, and glutathione metabolism pathways were significantly enriched among proteins only present in epididymal samples. Other proteins identified that may be related to epididymal sperm’s increased longevity were peroxidases and glutathione peroxidases for their antioxidant properties

Influence of estradiol on bovine trophectoderm and uterine gene transcripts around maternal recognition of pregnancy

Embryo survival and pregnancy success is increased among animals that exhibit estrus prior to fixed time-artificial insemination, but there are no differences in conceptus survival to d16. The objective of this study was to determine effects of preovulatory estradiol on uterine transcriptomes, select trophectoderm (TE) transcripts, and uterine luminal fluid proteins. Beef cows/heifers were synchronized, artificially inseminated (d0), and grouped into either high (highE2) or low (lowE2) preovulatory estradiol. Uteri were flushed (d16); conceptuses and endometrial biopsies (n = 29) were collected. RNA sequencing was performed on endometrium. Real-time polymerase chain reaction (RT-PCR) was performed on TE (n = 21) RNA to measure relative abundance of IFNT, PTGS2, TM4SF1, C3, FGFR2, and GAPDH. Uterine fluid was analyzed using 2D Liquid Chromatography with tandem mass spectrometry-based Isobaric tags for relative and absolute quantitation (iTRAQ) method. RT-PCR data were analyzed using the MIXED procedure in SAS. There were no differences in messenger RNA (mRNA) abundances in TE, but there were 432 differentially expressed genes (253 downregulated, 179 upregulated) in highE2/conceptus versus lowE2/conceptus groups. There were also 48 differentially expressed proteins (19 upregulated, 29 downregulated); 6 of these were differentially expressed (FDR \u3c 0.10) at the mRNA level. Similar pathways for mRNA and proteins included: calcium signaling, protein kinase A signaling, and corticotropin-releasing hormone signaling. These differences in uterine function may be preparing the conceptus for improved likelihood of survival after d16 among highE2 animals

Governing a shared hidden resource: A review of governance mechanisms for transboundary groundwater security

© 2017 Elsevier B.V. Globally, groundwater is by far the largest store of liquid freshwater, making it a key component of a secure water supply. However, over the past few decades the amount of usable groundwater available around the world has rapidly decreased. This depletion is caused primarily by mismanagement (e.g., overpumping, contamination, and under-regulation), but also by reduced natural recharge due to climate change and urbanization. Management of groundwater resources is particularly challenging for the nearly 600 aquifers that are transboundary, meaning that they extend across international political borders. To understand how governance mechanisms can reduce water insecurity in transboundary groundwater contexts, we review key literature from what we view as the most relevant fields: groundwater management, water security, international water law and international water governance. We then formulate a set of recommendations for improved groundwater governance that can address the specific physical nature of groundwater systems, enhance water security, and apply to transboundary groundwater settings. We argue that groundwater governance in transboundary contexts requires processes that (1) enhance context-specific and flexible international mechanisms; (2) address the perpetual need for groundwater data and information; (3) prioritize the precautionary principle and pollution prevention, in particular; (4) where appropriate, integrate governance of surface and subsurface water and land; and (5) expand institutional capacity, especially of binational or multinational actors

Non-Commutative Inflation

We show how a radiation dominated universe subject to space-time quantization may give rise to inflation as the radiation temperature exceeds the Planck temperature. We consider dispersion relations with a maximal momentum (i.e. a mimimum Compton wavelength, or quantum of space), noting that some of these lead to a trans-Planckian branch where energy increases with decreasing momenta. This feature translates into negative radiation pressure and, in well-defined circumstances, into an inflationary equation of state. We thus realize the inflationary scenario without the aid of an inflaton field. As the radiation cools down below the Planck temperature, inflation gracefully exits into a standard Big Bang universe, dispensing with a period of reheating. Thermal fluctuations in the radiation bath will in this case generate curvature fluctuations on cosmological scales whose amplitude and spectrum can be tuned to agree with observations.Comment: 4 pages, 3 figure