Tabular–type uranium ore deposits (the Hangjinqi and Daying deposits) have recently been found in the Middle Jurassic Zhiluo Formation, north of the Ordos Basin, China. Petrographic observations, the ...chemical composition of U minerals determined by EMPA and fs–LA–ICP–MS, whole rock geochemistry and the microthermometric study of fluid inclusions have been integrated to characterize the genetic conditions of the U mineralization in the Hangjinqi sandstone–hosted deposit. Two different groups of U minerals have been identified. One group includes coffinite(I) associated with vanadium–rich micas. Coffinite(I) is enriched in vanadium (V) and devoid of iron (Fe) and yttrium (Y) and has a LREE–enriched chondrite–normalized REE pattern. The U minerals of this group are similar to meteoric fluid infiltration related deposits. The second group has coeval coffinite(II) and coarsely crystalline calcite cement. Coffinite(II) is enriched in Y and Fe and depleted in V and is marked by a flat chondrite–normalized REE pattern, which is compatible with typical hydrothermal genetic deposits with high–salinity mineralizing fluids. The temperature and salinity of the primary aqueous inclusions in the ore–stage calcite are 120–180°C and 8.00–16.34% (eq. wt% NaCl), respectively. These mineral assemblages, temperatures and salinities indicate that the Hangjinqi deposit was affected by two distinct types of ore–bearing fluids: low–salinity meteoric waters and high–salinity hydrothermal fluids. The meteoric fluids event began at 97±5Ma with the titling of the northern Ordos Basin and the uplift of the Hetao region to the north. Hydrothermal U mineralization occurred since 39±2Ma with the rifting of the Hetao graben. Thus, the previous biogenic model for the U mineralization should be modified in the uraniferous region of the north Ordos Basin.
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•EMPA and fs–LA–ICP–MS were performed for in–situ analyses of U–minerals in the Hangjinqi deposit.•Two distinct types of ore–forming fluids are identified: low–salinity meteoric waters and high–salinity hydrothermal fluids.•With the discovery of hydrothermal mineralization, the previous biogenic model should be modified for the U deposits.
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•Diagenetic green altered sandstone related to hydrocarbon migration was recognized.•Chemical reduction caused the mobilization of Fe via dissolution of hematite.•Incorporation of the ...mobilized Fe into diagenetic chlorite imparts the green color.•The green altered sandstone was the product of hydrocarbon-water-rock interactions under sulfur-depleted, reducing conditions.•Hydrocarbon-induced alterations can serve as exploration guides for sandstone-hosted uranium deposits.
The formation of sandstone-hosted uranium deposits has been linked to upward migration of hydrocarbons in many sedimentary basins. However, hydrocarbon-induced diagenetic alterations associated with uranium mineralization and preservation are rarely discussed. Here, we report the bleaching of red sandstone to green in the Middle Jurassic Zhiluo Formation from the uranium deposits in the northern Ordos Basin, China. The original gray sandstone underwent oxidation and was reddened by the downward flow of meteoric water from the northern margin of the basin during the Late Cretaceous–Cenozoic uplift. This process resulted in the leaching of preore-stage uranium concentration and oxidation of preore pyrite in the organic matter-rich sandstone. Uranyl and sulfate ions were carried downward through the host sandstone by oxygenated groundwater. Meanwhile, hydrocarbons migrated upward and reacted with the downward flowing oxidizing fluids, which induced uranium mineralization at the redox interface between the red and gray sandstone where iron was reduced to Fe2+ and incorporated into pyrite cement. The highly negative 34S values (−58.0‰ to −33.4‰ V-CDT) of the pyrite indicate that it originated from bacterial sulfate reduction during hydrocarbon biodegradation. Abundant organic acids and CO2 were generated from hydrocarbon oxidation, resulting in the dissolution of feldspars and the precipitation of kaolinite in the mineralized sandstone. With the formation of the Cenozoic Hetao graben to the north, the gravity-driven flow of meteoric water was limited, resulting in progressive halting of epigenetic uranium mineralization. Then, the upward hydrocarbons dominated the fluid system throughout the northern slope of the basin and bleached the previous red sandstone updip, which set up a strong reducing environment and protected the early formed uranium deposits at the paleo-redox front from oxidation and remobilization. Due to the oxygen and sulfur supply absence, the iron released from hematite during bleaching was immobilized and incorporated into Fe-rich chlorite that imparts the green color, rather than into pyrite or reprecipitation as hematite. This study provides insights for the processes of hydrocarbon-water-rock interactions associated with uranium mineralization and preservation, which can serve as exploration guides for sandstone-hosted uranium deposits.
We previously reported that at term pregnancy, a decline in myometrial protein kinase A (PKA) activity leads to an exchange protein activated by cyclic AMP (Epac1)-dependent increase in oxytocin ...receptor (OTR) expression, promoting the onset of labour. Here, we studied the changes in the cyclic adenosine monophosphate (cAMP) effector system present in different phenotypes of preterm labour (PTL). Myometrial biopsies obtained from women with phenotypically distinct forms of PTL and the levels of PKA and OTR were examined. Although we found similar changes in the cAMP effector pathway in all forms of PTL, only in the case of twin PTL (T-PTL) was myometrial OTR levels increased in association with these results. Although there were several changes in the mRNA levels of components of the cAMP synthetic pathway, the total myometrial cAMP levels did not change with the onset of any subtype of PTL. With regards to the expression of cAMP-responsive genes, we found that the mRNA levels of 4 of the 5 cAMP-down-regulated genes were increased in T-PTL, similar to our findings in term labour. These data signify that although changes in the cAMP effector system were common to all forms of PTL, only in T-PTL were OTR levels increased. Similarly, the mRNA levels of cAMP-repressed genes were only increased in T-PTL supporting the concept that the decline in PKA levels influences myometrial function driving the onset of T-PTL.
Previously, we showed that cAMP increased COX-2 expression in myometrial cells via MAPK. Here, we have extended these observations, using primary myometrial cell cultures to show that the cAMP ...agonist, forskolin, enhances IL-1β-driven COX-2 expression. We then explored the role of A-kinase interacting protein (AKIP1), which modulates the effect of PKA on p65 activation. AKIP1 knockdown reversed the effect of forskolin, such that its addition inhibited IL-1β-induced COX-2 mRNA expression and reduced the IL-1β-induced increase in nuclear levels of p65 and c-jun. Forskolin alone and with IL-1β increased IκBα mRNA expression suggesting that in the context of inflammation and in the presence of AKIP1, cAMP enhances p65 activation. AKIP1 knockdown reversed these changes. Interestingly, AKIP1 knockdown had minimal effect on the ability of forskolin to repress either basal OTR expression or IL-1β-stimulated OTR mRNA expression. AKIP1 was up-regulated by IL-1β, but not stretch and was repressed by cAMP. The mRNA expression of AKIP1 increased in early labour in tandem with an increase in COX-2 mRNA and protein. AKIP1 protein levels were also increased with inflammation and stretch-induced preterm labour. Our results identify a second important cAMP effector-switch occurring at term in human myometrium and suggest that a hitherto unrecognized interaction may exist between AKIP1, NFκB and AP-1. These data add to the proposition that cAMP acts as a key regulator of human myometrial contractility.
Our previous work has shown myometrial PKA activity declines in term and twin-preterm labour in association with an increase in the expression of the oxytocin receptor (OTR). Here we investigate the ...action of cAMP/PKA in basal conditions, with the addition of progesterone (P4) and/or IL-1β to understand how cAMP/PKA acts to maintain pregnancy and whether the combination of cAMP and P4 would be a viable therapeutic combination for the prevention of preterm labour (PTL). Further, given that we have previously found that cAMP enhances P4 action we wanted to test the hypothesis that changes in the cAMP effector system are responsible for the functional withdrawal of myometrial P4 action. Myometrial cells were grown from biopsies obtained from women at the time of elective Caesarean section before the onset of labour. The addition of forskolin, an adenylyl cyclase activator, repressed basal OTR mRNA levels at all doses and P4 only enhanced this effect at its highest dose. Forskolin repressed the IL-1β-induced increase in OTR mRNA and protein levels in a PKA-dependent fashion and repressed IL-1β-activation and nuclear transfer of NFκB and AP-1. P4 had similar effects and the combination P4 and forskolin had greater effects on OTR and NFκB than forskolin alone. While PKA knockdown had no effect on the ability of P4 to repress IL-1β-induced OTR expression it reversed the repressive effect of the combination of P4 and forskolin and resulted in a greater increase than observed with IL-1β alone. These studies suggest that cAMP acts via PKA to repress inflammation-driven OTR expression, but that when PKA activity is reduced, the combination of cAMP and P4 actually enhances the OTR response to inflammation, promoting the onset of labour and suggesting that changes in the cAMP effector system can induce a functional P4 withdrawal.
The process of parturition involves the transformation of the quiescent myometrium (uterine smooth muscle) to the highly contractile laboring state. This is thought to be driven by changes in gene ...expression in myometrial cells. Despite the existence of multiple myometrial gene expression studies, the transcriptional programs that initiate labor are not known. Here, we integrated three transcriptome datasets, one novel (NCBI Gene Expression Ominibus: GSE80172) and two existing, to characterize the gene expression changes in myometrium associated with the onset of labor at term. Computational analyses including classification, singular value decomposition, pathway enrichment, and network inference were applied to individual and combined datasets. Outcomes across studies were integrated with multiple protein and pathway databases to build a myometrial parturition signaling network. A high-confidence (significant across all studies) set of 126 labor genes were identified and machine learning models exhibited high reproducibility between studies. Labor signatures included both known (interleukins, cytokines) and unknown (apoptosis,
, cell proliferation/differentiation) pathways while cyclic AMP signaling and muscle relaxation were associated with non-labor. These signatures accurately classified and characterized the stages of labor. The data-derived parturition signaling networks provide new genes/signaling interactions to understand phenotype-specific processes and aid in future studies of parturition.
Progesterone is widely used to prolong gestation in women at risk of preterm labour (PTL), and acts at least in part via the inhibition of inflammatory cytokine-induced prostaglandin synthesis. This ...study investigates the mechanisms responsible for this inhibition in human myometrial cells. We used reporter constructs to demonstrate that interleukin 1beta (IL-1β) inhibits progesterone driven PRE activation via p65 activation and that IL-1β reduced progesterone driven gene expression (FKBP5). Conversely, we found that the activity of a p65-driven NFκB reporter construct was reduced by overexpression of progesterone receptor B (PRB) alone and that this was enhanced by the addition of MPA and that both MPA and progesterone suppressed IL-1β-driven cyclo-oxygenase-2 (COX-2) expression. We found that over-expressed Halo-tagged PRB, but not PRA, bound to p65 and that in IL-1β-treated cells, with no overexpression of either PR or p65, activated p65 bound to PR. However, we found that the ability of MPA to repress IL-1β-driven COX-2 expression was not enhanced by overexpression of either PRB or PRA and that although the combined PR and GR antagonist Ru486 blocked the effects of progesterone and MPA, the specific PR antagonist, Org31710, did not, suggesting that progesterone and MPA act via GR and not PR. Knockdown using siRNA confirmed that both MPA and progesterone acted via GR and not PR or AR to repress IL-1β-driven COX-2 expression. We conclude that progesterone acts via GR to repress IL-1β-driven COX-2 activation and that although the interaction between p65 and PRB may be involved in the repression of progesterone driven gene expression it does not seem to be responsible for progesterone repression of IL-1β-induced COX-2 expression.
High throughput sequencing has previously identified differentially expressed genes (DEGs) and enriched signalling networks in human myometrium for term (≥37 weeks) gestation labour, when defined as ...a singular state of activity at comparison to the non-labouring state. However, transcriptome changes that occur during transition from early to established labour (defined as ≤3 and >3 cm cervical dilatation, respectively) and potentially altered by fetal membrane rupture (ROM), when adapting from onset to completion of childbirth, remained to be defined. In the present study, we assessed whether differences for these two clinically observable factors of labour are associated with different myometrial transcriptome profiles. Analysis of our tissue ('bulk') RNA-seq data (NCBI Gene Expression Omnibus: GSE80172) with classification of labour into four groups, each compared to the same non-labour group, identified more DEGs for early than established labour; ROM was the strongest up-regulator of DEGs. We propose that lower DEGs frequency for early labour and/or ROM negative myometrium was attributed to bulk RNA-seq limitations associated with tissue heterogeneity, as well as the possibility that processes other than gene transcription are of more importance at labour onset. Integrative analysis with future data from additional samples, which have at least equivalent refined clinical classification for labour status, and alternative omics approaches will help to explain what truly contributes to transcriptomic changes that are critical for labour onset. Lastly, we identified five DEGs common to all labour groupings; two of which (AREG and PER3) were validated by qPCR and not differentially expressed in placenta and choriodecidua.
Carbonate concretions are conspicuous in organic‐rich shales and are generally related to decomposition of organic matter. The black shales from the Chang 7 Member of the Upper Triassic Yanchang ...Formation of the southern Ordos Basin host abundant carbonate concretions, which provide a unique record of depositional and early diagenetic conditions of the paleo‐lake sediments. However, little attention has been given to the genesis and growth processes of the concretions in these lacustrine petroleum source rocks. New petrographic observations and geochemical analysis show that the concretions are composed of calcite, phosphate fossil fragments, K‐NH4‐feldspar, quartz, bitumen, and minor Fedolomite. Phosphate minerals, mainly carbonate fluorapatite (CFA), show pervasive replacement by calcite, most of which contains phosphorus, ranging in concentration from 0.26 to 2.35 wt%. This suggests that the phosphate minerals are the precursors for concretion growth. Positive δ13C (+5.6 to +12.4 ‰ V‐PDB) signatures and the absence of pyrite indicate that microbial methanogenesis was the dominant driver for concretion growth, rather than bacterial sulfate reduction. Quartz, bitumen, and Fe‐dolomite are the last cements that occurred, at deep burial depths and high temperatures. The formation of phosphate minerals might have been induced by upwelling of phosphate‐enriched deep water in the Late Triassic paleolake, which promoted phytoplankton blooms and further enrichment of organic matter. Extremely slow sedimentation rates of fine‐grained detrital minerals, relative to dead organism accumulation, led to the high permeabilities of the organic‐rich sediments and rapid concretion growth during shallow burial. The close association of phosphate‐bearing carbonate concretions and organic‐rich shales reflects that upwelling played a critical role in the formation of the high‐quality petroleum source rocks in the Triassic paleo‐Ordos lake.
Reasonable production allocation of tight sandstone gas reservoirs is an important basis for efficient development of wells. Combining multiple mathematical models, the modified flowing material ...balance equation was established considering the variation of viscosity and compressibility, and a reasonable production allocation process was developed. The results show that: ① The flow material balance method ignores the change of compressibility, viscosity and deviation coefficient in the calculation. Compared with the results calculated by the material balance method, the results of the flow material balance method are smaller. ② A modified flowing material balance method is established, verified by the production of 670 wells in the study area during stable period. Compared with the open flow rate method, the error of dynamic reserve allocation method is smaller, with an error of 0.07%. ③ When dynamic reserves are used to allocate production, the initial decline rate of wells is reduced by 74.65% on average, the production on stable period increases by 21.28%, and the time increases by 1.79%. This study provides support for dynamic reserve calculation and reasonable production allocation of gas wells in the study area, and has important guiding significance for the formulation of reasonable development plan and economic and efficient development of tight sandstone gas reservoirs.
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