Search

Background Planarians reliably regenerate all body parts after injury, including a fully functional head and central nervous system. But until now, the expression dynamics and functional role of miRNAs and other small RNAs during the process of head regeneration are not well understood. Furthermore, little is known about the evolutionary conservation of the relevant small RNAs pathways, rendering it difficult to assess whether insights from planarians will apply to other taxa. Results In this study, we applied high throughput sequencing to identify miRNAs, tRNA fragments and piRNAs that are dynamically expressed during head regeneration in Dugesia japonica. We further show that knockdown of selected small RNAs, including three novel Dugesia-specific miRNAs, during head regeneration induces severe defects including abnormally small-sized eyes, cyclopia and complete absence of eyes. Conclusions Our findings suggest that a complex pool of small RNAs takes part in the process of head regeneration in Dugesia japonica and provide novel insights into global small RNA expression profiles and expression changes in response to head amputation. Our study reveals the evolutionary conserved role of miR-124 and brings further promising candidate small RNAs into play that might unveil new avenues for inducing restorative programs in non-regenerative organisms via small RNA mimics based therapies.

A small GTPase, RhoA, plays a variety of functions in the regulation of cellular and developmental events via its downstream effectors, including cytokinesis, cell migration, and phagocytosis. In this study, a novel RhoA-related gene from the planarian Dugesia japonica, DjRhoA, was cloned and characterized. The full-length cDNA of DjRhoA is 869 bp, and the open reading frame encodes a poly-peptide of 194 amino acids. Phylogenetic analysis revealed that DjRhoA clustered with another RhoA-related protein, DjRho2, and located on the base of phylogenetic tree. Whole-mount in situ hybridization results indicated that DjRhoA was expressed in the brain primordia and intestine during regeneration. Knockdown of DjRhoA induces defects in the brain and intestine. These results suggested that DjRhoA was responsible for the regeneration of brain and intestine in Dugesia japonica.

The growth and differentiation of neurons are critical events in the establishment of proper neuron connectivity and function. Planarians have a remarkable ability to completely regenerate a functional nervous system from a pluripotent stem cell population. Thus, planarians provide a powerful model to identify genes required for neuronal differentiation in vivo. The Wnt/Ca2+ signaling pathway is crucial for cancer development, arousing inflammatory responses, and neurodegeneration. We analyzed the expression patterns and RNAi phenotypes for members of the Wnt/Ca2+ signaling pathway in the planarian, Dugesia japonica. The expression of DjWnt5a, DjPLC-β, DjCamKII, and DjCaln during regeneration was surprisingly similar and revealing in the regenerated brain. RNAi knockdown of DjWnt5a, DjPLC-β, DjCamKII, and DjCaln led to defects in regenerated brains including brain partial deletions, incompact phenotypes at the posterior of the new brain, and lateral branches, which could not regenerate. Furthermore, the expressions of GAD and the number of GABAergic neurons decreased. Together, these results suggest that the Wnt/Ca2+ signaling pathway is required for GABAergic neuron regeneration.

Occupational health and safety (OHS) training is an important way to avoid the risk of safety management in the construction industry. However, the statistics on construction accidents and deaths in China show that the effectiveness of OHS training in China is questionable. Through empirical investigations, based on the CART and comprehensive analysis model, this study explores the effectiveness of OHS training and its main influencing factors. It has been found that training effectiveness is positively related to whether to receive OHS training or not and also positively related to training methods. It has also been found that the effectiveness of training is positively related to the importance of post responsibility. The results show that the construction industry needs to strengthen the OHS system training of grass-root workers, and the training should be classified and graded according to the workers' educational backgrounds, training methods, job satisfaction, and job responsibilities. In the safety training management of on-site workers, salary is the basic factor, and more attention should be paid to the factors such as workers' physical safety, training and learning, and future career development. The research results can provide paths and suggestions for improving the effectiveness of occupational health and safety training in China's construction industry, and provide some reference for other developing countries to carry out OHS training.

Background: Occupational health and safety (OHS) training is an important way to prevent construction safety risks. However, the effectiveness of OHS training in China is questionable. In this study, the CHAID (chi-squared automatic interaction detection) decision tree, chi-square analysis, and correlation analysis were used to explore the main, secondary, weak, unrelated, and expectation factors affecting the effectiveness of training. It is the first to put forward the “five-factor method” of training effectiveness. It is found that training effectiveness is positively correlated with job responsibilities, OHS training, and job satisfaction. It is also significantly related to job certificate, training time, training method, and working time. However, the effectiveness of training has nothing to do with personal age, marital status, educational level, job type, and whether or not they have experienced industrial accidents. And the workers on site expect the enterprise to provide security and opportunities such as physical safety, training and learning, and future career development. The results show that OHS system training should be strengthened in the construction industry, and classified training should be carried out according to post responsibility, training methods, job satisfaction, and working hours.

To explore the relations between the number of accident deaths (NCD) and various factors in construction safety, a multiple linear regression model was established, based on the panel data of economy, construction labor, and the number of accident deaths in 31 provinces (regions) of China from 2009 to 2018. The results show that the average total profits and taxes (TPAT), and the death rate of ten thousand people (DR) are positively correlated with NCD, while the labor productivity (LP) is negatively correlated with it. Under the condition that other factors remain unchanged, NCD increases by 0.02 per a hundred million CNY. However, if DR increases by one ten thousand, NCD will increase by 8.66 on average. On the contrary, when LP increases by a hundred million CNY per ten thousand people, NCD decreases by 0.19. The model also predicts NCD in different provinces and cities from 2019 to 2020 with the method of quadratic exponential smoothing. As well, practice results show that the model is effective and practical.

14-3-3 proteins are a family of highly conserved acidic proteins that regulate cellular processes. They act as a kind of important signaling molecules taking part in many crucial decisions throughout the development process. We have isolated and characterized two members of the 14-3-3 family, namely, Dj14-3-3 α and Dj14-3-3 ζ in the planarian Dugesia japonica. The Dj14-3-3 α and ζ genes encode polypeptides of 260 and 255 amino acids respectively. We have proved that the Dj14-3-3 α and ζ genes were especially expressed in the pharynx in adult and regenerating planarians by in situ hybridization and they were not involved in regeneration process. Besides, Dj14-3-3 α and ζ genes can compensate each other in planarians by RNA interference. The Dj14-3-3 α and ζ were significantly up-regulated expression when planarians were stimulated with the pathogen-associated molecular patterns including lipopolysaccharide (LPS), peptidoglycan (PGN), β-Glu and Poly (I:C), indicating that the Dj14-3-3 α and ζ may be involved in the immune responses.

Planarians are bilaterally symmetric metazoans of the phylum Platyhelminthes. They have well-defined anteroposterior and dorsoventral axes and have a highly structured true brain which consists of all neural cell types and neuropeptides found in a vertebrate. Planarian flatworms are famous for their strong regenerative ability; they can easily regenerate any part of the body including the complete neoformation of a functional brain within a few days and can survive a series of extreme environmental stress. Nowadays, they are an emerging model system in the field of developmental, regenerative, and stem cell biology and have offered lots of helpful information for these realms. In this review, we will summarize the response of planarians to some typical environmental stress and hope to shed light on basic mechanisms of how organisms interact with extreme environmental stress and survive it, such as altered gravity, temperature, and oxygen, and this information will help researchers improve the design in future studies.

The growth and differentiation of neurons are critical events in the establishment of proper neuron connectivity and function. Planarians have a remarkable ability to completely regenerate a functional nervous system from a pluripotent stem cell population. Thus, planarians provide a powerful model to identify genes required for neuronal differentiation in vivo. The Wnt/Ca

The discovery of RNAs (for example, messenger RNAs, non-coding RNAs) in sperm has opened the possibility that sperm may function by delivering additional paternal information aside from solely providing the DNA(1). Increasing evidence now suggests that sperm small non-coding RNAs (sncRNAs) can mediate intergenerational transmission of paternally acquired phenotypes, including mental stress(2,3) and metabolic disorders(4-6). How sperm sncRNAs encode paternal information remains unclear, but the mechanism may involve RNA modifications. Here we show that deletion of a mouse tRNA methyltransferase, DNMT2, abolished sperm sncRNA-mediated transmission of high-fat-diet-induced metabolic disorders to offspring. Dnmt2 deletion prevented the elevation of RNA modifications (m(5)C, m(2)G) in sperm 30-40 nt RNA fractions that are induced by a high-fat diet. Also, Dnmt2 deletion altered the sperm small RNA expression profile, including levels of tRNA-derived small RNAs and rRNA-derived small RNAs, which might be essential in composing a sperm RNA 'coding signature' that is needed for paternal epigenetic memory. Finally, we show that Dnmt2-mediated m(5)C contributes to the secondary structure and biological properties of sncRNAs, implicating sperm RNA modifications as an additional layer of paternal hereditary information.

Though there are numerous biological experiments, which have been performed in a space environment, to study the physiological effect of space travel on living organisms, while the potential effect of weightlessness or short-term hypergravity on the reproductive system in most species, particularly in mammalian is still controversial and unclear. In our previous study, we investigated the effect of space microgravity on the development of mouse 4-cell embryos by using Chinese SJ-8. .Unexpectedly, we did not get any developed embryo during the space-flight. Considering that the process of space experiment is quite different from most experiments done on earth in several aspects such as, the vibration and short-term hypergravity during the rock launching and landing. Thus we want to know whether the short-term hypergravity produced by the launch process affect the early embryo development in mice, and howthe early embryos respond to the hypergravity. In present study, we are mimicking the short-term hypergravity during launch by using a centrifuge to investigate its influence on the development of early embryo (2-cell) in mice. We also examined the actin filament distribution in 2-cell embryos by immunostaining to test their potential capacity of development under short-term hypergravity exposure. Our results showed that most 2-cell embryos in the hypergravity exposure groups developed into blastocysts with normal morphology after 72h cultured in vitro, and there is no obvious difference in the development rate of blastocyst formation compared to the control. Moreover, there were no statistically significant differences in birth rates after oviduct transfer of 2-cell mouse embryos exposed on short-term hypergravity compared with 1 g condition. In addition, the well-organized actin distribution appeared in 2-cell embryos after exposed on hypergravity and also in the subsequent developmental blastocysts. Taken together, our data shows that short-term exposure in hypergravity conditions does not affect the normal development and actin filament structures of mouse embryos.

Based on core description, conventional thin section, cast thin section and scanning electron microscope (SEM) analysis, combined with general physical analysis, the physical properties of the braided river delta sandstone reservoirs and the range of reservoir quality of the Sha 1 member have been analyzed in the southern Nanpu Sag of the Bohai Bay Basin. The characteristics and controlling factors of the southern provenance of Sha 1 reservoirs are examined to reveal the causes for the formation of deep, high-quality reservoirs more than 4000 m deep. Sha 1 reservoirs in the study area are made up of gravel rock, pebbled inequigranular sandstone, medium sand and gritrock. The lithology is mainly lithic feldspar sandstone, the contents of rigid particles like quartz and metamorphic rock cuttings are higher, the content of matrix is very low and the structure is supported by grains. The average porosity is 12.8%. The average permeability is 154.9×10−3μm2. The reservoir type is low porosity and high permeability. The reservoir space is mainly made up of primary and secondary pores. Parent rock type, sedimentary environment and the abnormal high pressure in the Sha 1 Member are the dominant factors controlling the reservoir properties. It is inferred that high quality sandstone reservoirs with high natural productivity of oil and gas are widely developed in the strata more than 4000 m deep in the Bohai Bay Basin, and so conventional sandstone reservoir exploration is expected to expand to these deeper intervals. Key words: Bohai Bay Basin, Nanpu Sag, Sha 1 Member, braided river delta, deep strata, reservoir characteristics

Natural gas and condensate oil and gas have been discovered in structures in the beach area of the Nanpu sag, Bohai Bay Basin, eastern China. The gas is dominantly hydrocarbon gas with less non–hydrocarbons, it is wet gas and has a dry coefficient in the range of 0.7–0.9. The gas has a methane carbon isotope in the range of −44‰–36‰ and a ethane carbon isotope in the range of −30‰– −24‰. Analysis of the relationship charts between 13C1–C1/C2+3 and δ13CCH4–δDCH4, δ13C– Ro equation, Pr/Ph of associated oil or condensate, suggests that the Cenozoic gas in the beach area of the Nanpu sag is mature – high mature oil–type gas. According to analysis of origin and source of the gas and condensate oil, in combination of monomer hydrocarbon carbon isotope and biomarker, the Cenozoic gas in the beach area of the Nanpu sag is sourced from the Tertiary Shahejie Formation Sha 3 Member (Es3) source rocks and Sha 1 Member (Es1) source rocks. Among these gases, the gas from Es3 source rocks is equivalent to condensate gas formed when source rock vitrinite reflectance ( Ro) is at or above 1.3%. This type of gas has heavier carbon isotope, ethane carbon isotope generally more than −27‰, associated oil C24–tetracyclic terpane /C26–tricyclic terpane ratio less than 0.7, the distribution of monomer hydrocarbon carbon isotopes being flat. The gas from Es1 source rocks is equivalent to oil–associated gas formed when source rock vitrinite reflectance ( Ro) is at or below 1.0%. This type of gas has lighter carbon isotope, ethane carbon isotope generally less than −28‰, associated oil C24–tetracyclic terpane /C26–tricyclic terpane ratio more than 1.0, the distribution of monomer hydrocarbon carbon isotopes having clear inflection points. This study provides reference to study of gas origin in a complicated region, and makes a further step to show exploration potential and fields for gas in the Nanpu sag.

Quantum-chemical calculations on some linear or non-linear C 28 H 20 and C 36 H 24 isomers composed of hexaprismane cages which are parallel or perpendicular to each other have been performed using density functional theory (DFT) method. The electronic structures, thermal energies, and vertical ionization potential as well as vertical electron affinity of various isomers have been obtained at the B3LYP/6-31G(d,p) level. And some meaningful conclusions have been speculated. Meanwhile, the present paper has also computed the enthalpies of formation for different isomers so as to evaluate their stability from a thermodynamic point of view. It has been concluded that the linear isomer in which the hexaprismane cages are perpendicular is more stable and has smaller enthalpy of formation.

The transition process of the thermocapillary convection from a steady and axisymmetric mode to the oscillatory mode in a liquid bridge with a fixed aspect ratio and varied volume ratio was studied experimentally. To ensure the surface tension to play an important role in the ground-based experiment, the geometrical configuration of the liquid bridge was so designed that the associated dynamic Bond number Bd ≈ 1. The velocity fields were measured by Particle Image Velocimetry (PIV) technique to effectively distinguish the different flow modes during the transition period in the experiments. Our experiments showed that as the temperature difference increased the slender and fat bridges presented quite different features on the evolution in their flow feature: for the former the thermocapillary convection transformed from a steady and axisymmetric pattern directly into an oscillatory one; but for the latter a transition flow status, characterized by an axial asymmetric steady convection, appeared before reaching the oscillatory mode. Experimental observations agree with the results of numerical simulations and it is obvious that the volume of liquid bridge is a sensitive geometric parameter. In addition, at the initial stage of the oscillation, for the former a rotating oscillatory convection with azimuthal wave number m = 1 was observed while for the latter a pulsating oscillatory pattern with azimuthal wave number m = 2 emerged, and then with further increase of the temperature difference, the pulsating oscillatory convection with azimuthal wave number m = 2 evolved into a rotating oscillatory pattern with azimuthal wave number m = 2.

This paper assesses the potential of natural Chinese clinoptilolite for ammonia removal from aqueous solution. In batch study, the effects of relevant parameters, such as contact time, pH and initial ammonia concentration were examined, respectively. The results show that although contact time needs at least 4 h in order to attain exchange equilibrium, ammonia removal by clinoptilolite occurs rapidly within the first 15 min of contact time; the pH has an effect on ammonia removal efficiency as it can influence both the character of the exchanging ions and the clinoptilolite itself; the ammonia removal capacity of clinoptilolite increases with the increase of initial ammonia concentration. In column study, clinoptilolite bed was exhausted at different flow velocities and ammonia breakthrough capacity of clinoptilolite bed was calculated. Furthermore, the optimum regeneration conditions were considered. The results show that flow velocity can affect breakthrough capacity of clinoptilolite by changing hydraulic retention time and the volume of 15–20 BV of 0.5 mol/L sodium chloride solution at pH 11–12 is sufficient for complete regeneration of clinoptilolite in column.

Persistent organic pollutants (POPs) such as polycyclic aromatic hydrocarbons (PAHs) are of great concern due to their persistence, bioaccumulation and toxic effects. In this work, 16 PAHs included in the US Environmental Protection Agency's (EPA) priority pollutant list were analyzed using solid-phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS) with a selected ion monitoring (SIM) mode. Reclaimed water and surface water sampling was undertaken in Tianjin, northern China. Total PAH concentrations varied from 1800 to 35,000 ng/L in surface waters (main rivers, tributaries, ditches, etc.) with mean value of 14,000 ng/L and from 227 to 600 ng/L in reclaimed water with mean value of 352 ng/L, respectively. The PAH profiles were dominated by low molecular weight PAHs (two- and three-ring components) in reclaimed water samples and surface water samples. These indicated that PAHs in reclaimed water and surface water might origin from oil or sewage contamination (petrogenic input). To elucidate sources, molecular indices based on indices among phenanthrene versus anthracene and fluoranthene versus pyrene were used to evaluate the possible source (pyrogenic and petrogenic sources, respectively) of PAH contamination in reclaimed water and surface water. The collected data showed that petrogenic input was predominant at almost all the stations investigated. To discriminate pattern differences and similarities among samples, principal component analysis (PCA) was performed using a correlation matrix. PCA revealed the latent relationships among all the surface water stations investigated and confirmed our analytical results. The analysis results of the ratios and PCA in this study showed that the ratios and PCA could be applied to the surface water investigation to some extent.

Author(s): Zhang, Yunfang; Zhang, Ying; Shi, Junchao; Zhang, He; Cao, Zhonghong; Gao, Xuan; Ren, Wanhua; Ning, Yunna; Ning, Lina; Cao, Yujing; Chen, Yongchang; Ji, Weizhi; Chen, Zi-Jiang; Chen, Qi; Duan, Enkui

Quantum-chemical calculations on some possible isomers of C 24 O derived from C 24 have been performed using density functional theory (DFT) method. The geometric structures, relative energies and electronic structures of various C 24 O isomers at the ground state have been calculated at the B3LYP/6-31G(d) level. And the 1,4-C 24 O(I) isomer was found to be the most stable geometry where the oxygen atom was added to the longest carbon carbon bond derived from the C 24 (D 6 ) isomer in the present paper. Based on the optimized neutral geometries at B3LYP/6-31G(d), the vertical ionization potential and vertical electron affinity have been analyzed. Meanwhile, the vibrational frequencies and IR spectrum of various C 24 O isomers have been obtained.

In rodent species, the ovary and the end of oviduct are encapsulated by a thin membrane called ovarian bursa. The biological functions of ovarian bursa remain unexplored despite its structural arrangement in facilitating oocytes transport into oviduct. In the present study, we observed a rapid fluid accumulation and reabsorption within the ovarian bursa after ovarian stimulation (PMSG-primed hCG injection), suggesting that the ovarian bursa might play an active role in regulating local fluid homeostasis around the timing of ovulation. We hypothesized that the aquaporin proteins, which are specialized channels for water transport, might be involved in this process. By screening the expression of aquaporin family members (Aqp1-9) in the ovarian tissue and isolated ovarian bursa (0, 1, 2 and 5 h after hCG injection), we found that AQP2 and AQP5 mRNA showed dynamic changes after hCG treatment, showing upregulation at 1-2 h followed by gradually decrease at 5 h, which is closely related with the intra-bursa fluid dynamics. Further immunofluorescence examinations of AQP2 and AQP5 in the ovarian bursa revealed that AQP2 is specifically localized in the outer layer (peritoneal side) while AQP5 localized in the inner layer (ovarian side) of the bursa, such cell type specific and spatial-temporal expressions of AQP2 and 5 support our hypothesis that they might be involved in efficient water transport through ovarian bursa under ovulation related hormonal regulation. The physiological significance of aquaporin-mediated water transport in the context of ovarian bursa still awaits further clarification.

Continuous disposal of endocrine-disrupting compounds (EDCs) into the environment can lead to serious human health problems and can affect plants and aquatic organisms. The determination of EDCs in water has become an increasingly important activity due to our increased knowledge about their toxicities, even at low concentration. The EDCs in water samples from the reclaimed water plant of Tianjin, northern China, were identified by gas chromatography (GC)-mass spectrometry (MS). Important and contrasting EDCs including estrone (E1), 17beta-estradiol (E2), 17alpha-ethynylestradiol (EE2), 4-tert-octylphenol (OP), 4-nonylphenol (NP), bisphenol A (BPA), di-n-butyl phthalate (DnBP), diisobutyl phthalate (DIBP), and di(2-ethylhexyl)phthalate (DEHP) were selected as the target compounds. Concentrations of steroid hormones, alkylphenolic compounds and phthalates ranged from below the limit of detection (LOD) to 8.1 ng L(-1), fromLOD to 14.2 ng L(-1), and from 1.00 microg L(-1) to 23.8 microg L(-1), respectively. The average removal efficiencies for target EDCs varied from 30% to 82%. These results indicate that environmental endocrine disrupting compounds are not completely removed during reclaimed water treatment and may be carried over into the general aquatic environment.

Distribution of the tributyltin (TBT) between egg-phosphatidylcholine membranes (liposome) and water under different pH and a comparison between the partition of TBT into lipid membranes and into octanol were studied. The distribution of this compound into both lipid membranes and octanol increased with pH. The major difference was that at lower pH, where ionized TBT dominated distribution was greater into lipid membranes compared to that of octanol. At high pH, where TBT predominates as neutral species, the distribution ratios were very similar in the octanol and the liposome-water system. These differences can be attributed to the properties of the biomembrane. The results indicated that the liposome-water partition model appears to be a better molecular descriptor for ionogenic organic compounds.