Effect of Prolactin on Gonadotropin Regulation of Mouse Ovarian Function

We have demonstrated that prolactin inhibits gonadotropin-induced ovulation in PMSG-primed mice.The number of ova in oviducts considerably decreased in the group of hCG plus prolactin (PRL)(19.7 + 4.9) as compared with that of hCG alone (31.7 + 6.7). PRL inhibition of hCG-inducedovulation in mice may be through decreasing the ovarian plasminogen activator (PA) activity on onehand, and inhibiting the preovulatory increase in estrogen (E) secretion on the other.     

Effects of transportation direction of photosynthate on soil microbial processes in the rhizosphere of Phyllostachys bissetii北大核心CSCD

Aims Clonal integration contributes greatly to the adaption of clonal plants to heterogeneous habitats. However, effects of transportation direction of photosynthate on microbial processes need to be further investigated in the rhizosphere. The purpose of this study is to determine the effects of directional differences in photosynthate transport on microbial processes in the rhizosphere of clonal plant Phyllostachys bissetii. Methods By removing the aboveground parts of the ramets, acropetal treatment and basipetal treatment were applied in this study to control the transportation direction of photosynthate. In acropetal treatment, aboveground parts of distal ramets were cut off (with 20 cm above ground kept), and proximal ramets were left intact. While in basipetal treatment, aboveground parts of proximal ramets were cut off (with 20 cm above ground kept), and distal ramets were left intact. Rhizomes between the two ramets were either connected or severed. Carbon (C) and nitrogen (N) availabilities, and enzyme activities in the rhizosphere soils were measured. Important findings In acropetal treatment, total organic carbon (TOC), dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and soil inorganic nitrogen (NH4 +-N and NO3 --N) content in the rhizosphere soil of distal ramets with connected rhizomes were significantly higher than those with severed rhizome. The activities of urease, polyphenol oxidase (POXase), N-acetyl-β-D-Glucosaminidase (NAGase) were significantly enhanced. Further, clonal integration had a significant effect on C and N availability, and microbial processes in the rhizosphere soil of neighbouring ramets. In basipetal treatment, clonal integration did not show a significant effect on C availability in the rhizosphere soil of proximal ramets, but microbial processes along with soil enzyme activities were altered accordingly. Effects of transportation direction of photosynthate on microbial processes in the rhizosphere of P. bissetii provides insights into the adaptation mechanisms of clonal plant populations. © 2018 Editorial Office of Chinese Journal of Plant Ecology. All rights reserved.     

Mathematical modeling and analysis of meningococcal meningitis transmission dynamics

Meningococcal meningitis(MCM)is one of the serious public health threats in the tropical and sub-tropical regions.In this paper,we propose an epidemic model to study the transmission dynamics of MCM with high-and low-risk susceptible populations.The model considers two different groups of susceptible individuals depending on the availability of medical resources(MR,including hospitals,health workers,etc.),which varies the infection risk.We find that the model exhibits the phenomenon of backward bifurcation(BB),which increases the difficulty of MCM control since the dynamics are not merely relying on the basic reproduction number,TZo.This study explores the effects of MR on the MCM epidemics by mathematical analysis and shows the existence of BB on MCM disease.Our findings suggest that providing adequate MR in a community is crucial in mitigating MCM incidences and deaths,especially,in the MCM endemic regions.     

Modulation of dragon’s blood on tetrodotoxin-resistant sodium currents in dorsal root ganglion neurons and identification of its material basis for efficacy

To clarify the modulation of dragon's blood on the tetrodotoxin-resistant (TTX-R) sodium currents in dorsal root ganglion (DRG) neurons and explore its corresponding material basis for the efficacy, using whole-cell patch clamp technique, the effects of dragon's blood and the combined effects of three components (cochinchinenin A, cochinchinenin B, and loureirin B) extracted from dragon's blood on the TTX-R sodium currents in acute-isolated DRG neurons of rats were observed. According to the operational definition of material basis for the efficacy of TCM established, the material basis of the modulation on the TTX-R sodium currents in DRG neurons of dragon's blood was judged from the experimental results. The drug interaction equation of Greco et al. was used to assess the interaction of the three components extracted from dragon's blood. This investigation demonstrated that dragon's blood suppressed the peak TTX-R sodium currents in a dose-dependent way and affected the activations of TTX-R sodium currents. The effects of the combination of cochinchinenin A, cochinchinenin B, and loureirin B were in good agreement with those of dragon's blood. Although the three components used alone could modulate TTX-R sodium currents, the concentrations of the three components used alone were respectively higher than those used in combination when the inhibition rates on the TTX-R sodium currents of them used alone and in combination were the same. The combined effects of the three components were synergistic. These results suggested that the interference with pain messages caused by the modulation of dragon's blood on TTX-R sodium currents in DRG neurons may explain some of the analgesic effect of dragon's blood and the corresponding material basis for the efficacy is the combination of cochinchinenin A, cochinchinenin B, and loureirin B.     

Biomarkers of Alzheimer’s disease in body fluids

Various innovative diagnostic methods for Alzheimer’s disease (AD) have been developed in view of the increasing preva-lence and consequences of later-life dementia. Biomarkers in cerebrospinal fluid (CSF) and blood for AD are primarily based on the detection of components derived from amyloid plaques and neurofibrillary tangles (NFTs). Published reports on CSF and blood biomarkers in AD indicate that although biomarkers in body fluids may be utilized in the clinical diagnosis of AD, there are no specific markers that permit accurate and reliable diagnosis of early-stage AD or the monitoring of disease pro-gression.     

Mediation by calcium/calmodulin-dependent protein kinase II of suppression of GABA_A receptors by NMDA

Using nystatin-perforated whole-cell recording configuration, the modulatory effect of N-methyl-D-aspartate (NMDA) on γ-aminobutyric acid (GABA)-activated whole-cell currents was investigated in neurons freshly dissociated from the rat sacral dorsal commissural nucleus (SDCN). The results showed that: (i) NMDA suppressed GABA- and muscimol (Mus)-activated currents (IGABA and IMUS), respectively in the Mg2 -free external solution containing 1 μmol/L glycine at a holding potential (VH) of -40 mV in SDCN neurons. The selective NMDA receptor antagonist, D-2-amino-5-phosphonovaleric acid (APV, 100 μmol/L), inhibited the NMDA-evoked currents and blocked the NMDA-induced suppression of IGABA; (ii) when the neurons were incubated in a Ca2 -free bath or pre-loaded with a membrane-permeable Ca2 chelator, BAPTA AM (10 nmol/L), the inhibitory effect of NMDA on IGABA disappeared. Cd2 (10 μmol/L) or La3 (30 μmol/L), the non-selective blockers of voltage-dependent calcium channels, did not affect the suppressio     

Photosynthetic characteristics of Dunaliella salina (Chlorophyceae,Dunaliellales) in relation to β-carotene content

Photosynthetic characteristics of Dunaliella salina with high (red form) and low β-carotene (green form) concentrations were studied. D. salina growing in brine saltworks exhibited a high level of β-carotene (15 pg cell⁻¹). The rate of oxygen evolution as a function of irradiance was higher in the red than in the green form (on chlorophyll basis). Photosynthetic inhibition of the green form was observed above 500 μmol m⁻² s⁻¹. The red form appeared more resistant to high irradiance and no inhibition in O₂ evolution was observed up 2000 μmol m⁻² s⁻¹. However, when these results are expressed on a cell number basis the rate of oxygen evolution was significantly higher in the green form. Carbonic anhydrase (CA) activity (total, soluble, membrane bound) was found in red and green forms. CA was higher in the red form on a chlorophyll basis, but lower if expressed on a protein basis. The light dependent rate of oxygen evolution and photoinhibition depends on the concentration of β-carotene in D. salina cells.     

Phylogenetic Relationship of Dendranthema （DC.） Des Moul. Revealed by Fluorescent In Situ Hybridization

Phylogenetic relationships of the different species in the genus Dendranthema (DC.) Des Moul. were estimated based on chromosome fluorescent in situ hybridization (FISH) with 18S-26S rDNA of Arabidopsis and genomic DNA of Dendranthema as probes. The results revealed that there was no positive correlation between the number of nuclear organization region (NOR) loci and the ploidy of Dendranthema.The exact cytogenetic information of NORs about 14 operational taxonomic units (OTUs) indicated that D.vestitum (Hemsl.) Ling et Shih was closer to the cultivars than other putative species, whereas D. zawadskii (Herb.) Tzvel. was the most distinct. The ambiguously distributed signals of genomic in situ hybridization (GISH) with genomic DNA of lower ploidy species as probes suggested that different genomes among Dendranthema were mixed. The result also indicated the limitation of GISH in studies on the phylogenetic relationships of the different species in this genus Dendranthema and on the origin of cultivated chrysanthemums. Based on these results and previous research, the origin of Chinese cultivated chrysanthemum is discussed.     

Different Effects of Homocysteine and Oxidized Low Density Lipoprotein on Methylation Status in the Promoter Region of the Estrogen Receptor α Gene

We investigated the effects of homocysteine (Hcy) and oxidized low density lipoprotein (ox-LDL) on DNA methylation in the promoter region of the estrogen receptor α (ERos) gene,and its potentialmechanism in the pathogenesis of atherosclerosis.Cultured smooth muscle cells (SMCs) of humans weretreated by Hcy and ox-LDL with different concentrations for different periods of time.The DNA methylationstatus was assayed by nested methylation-specific polymerase chain reaction,the lipids that accumulated inthe SMCs and foam cell formations were examined with Oil red O staining.The proliferation of SMCs wasassayed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method.The results showedthat ox-LDL in moderate concentrations (10-40 mg/L) induced de novo methylation in the promoter regionof the ERα gene of SMCs.However,high concentrations (50 mg/L) of ox-LDL,resulted in demethylation ofERα.The Hcy treatment resulted in de novo methylation in the promoter region of the ERα gene with aconcentration- and treating time-dependent manner,and a dose-dependent promoting effect on SMCproliferation.These data indicated that the two risk factors for atherosclerosis had the function of inducingde novo methylation in the promoter region of the ERα gene of SMCs. However,high concentrations (50rag/L) of ox-LDL induced demethylation,indicating that different risk factors of atherosclerosis with differentpotency might cause different aberrant methylation patterns in the promoter region of the ERα gene.Theatherogenic mechanism of Hcy might involve the hypermethylation of the ERα gene,leading to the proliferationof SMCs in atherosclerotic lesions.     

Effects of Interaction Between Cadmium and Plumbum on Phytochelatins and Glutathione Production in Wheat （Triticum aestivum L.）

Phytochelatins (PCs) may function as a potential biomarker for metal toxicity. However, less attention has been paid to the effects of metal interactions on the production of PCs and glutathione (GSH), the most prominent cellular thiol. In the present study, the effects of interactions between cadmium (Cd) and plumbum (Pb) on the production of PCs and GSH were monitored over a period of 14 d in wheat (Triticum aestivum L.) tissues. The results showed that combination of Cd and Pb led to synergistic growth inhibition in wheat. Exposure to Cd or Pb increased levels of PCs in a concentration-, tissue-, and time-dependent manner. Cadmium was more effective that Pb in increasing PCs production. Compared with the effects of Cd or Pb alone on the production of PCs, the combination of Cd and Pb acted synergistically, resulting in an enhanced production of PCs. Cadmium also stimulated GSH production in a concentration-, tissue-, and time-dependent manner. However, Pb had no obvious effects on GSH levels. The combination of Pb and Cd antagonized GSH production over the course of the growth period. The results of the present study suggest that metal interactions should be considered in the application of PCs and GSH as potential biomarkers for the evaluation of metal toxicity.     

Three-dimensional structures of virulence proteins of Legionella establish targets for new antibacterials

Legionella pneumophila, the causative agent of Legionnaires' disease, has been recognized as a major health problem responsible for an estimated number of 15 000-30 000 cases of severe pneumonia per year in Germany alone. Despite of the high clinical relevance, many aspects of the intracellular life-cycle of Legionella, especially details on interactions with host cells, are not well understood. Structural information on virulence proteins helps unravel basal pathogenicity mechanisms and is a prerequisite for the rational development of effective drug molecules. Here we discuss structures of three important virulence proteins of Legionella that have been determined in our laboratory. The structure of the macrophage infectivity potentiator (Mip) protein of Legionella pneumophila is the first of a novel subgroup within the family of FK506-binding protein (FKBP) peptidyl-prolyl cis/trans isomerases. On the basis of the Mip structure, promising antibacterial agents are being designed. Recently, structures of two equally exciting Legionella proteins have been reported. The ferrous iron transport protein FeoB is a transmembrane protein responsible for Fe²⁺ aquisition after entry of the pathogen into the host cell. The structure of the cytoplasmic domain of ferrous iron transporter (FeoB) provides insights into the family of prokaryotic G proteins and allows a detailed comparison with structures of related FeoBs. Furthermore, the characterization of DegQ, a periplasmatic chaperone-protease involved in protein quality control represents an intriguing example of how enzymatic activity is regulated by oligomerization as well as by an intrinsic loop activation cascade, depending on subtle conformational rearrangements.     

Glycine origin of the methyl substituent on C7′-N of octodiose for the biosynthesis of apramycin

Apramycin is unique in the aminoglycoside family due to its octodiose moiety. However, either the biosynthesis process or the precursors involved are largely unknown. Addition of glycine, as well as serine or threonine, to the Streptomyces tenebrabrius UD2 fermentation medium substantially increases the production of apramycin with little effect on the growth of mycelia, indicat-ing that glycine and/or serine might be involved in the biosynthesis of apramycin. The ¹³C-NMR analysis of [2-¹³C] glycine-fed (25% enrichment) apramycin showed that glycine specifically and efficiently incorporated into the only N-CH₃ substituent of apramycin on the C7′ of the octodiose moiety. We noticed that the in vivo concentration of S-adenosyl methionine increased in parallel with the addition of glycine, while the addition of methione in the fermentation medium significantly decreased the productivity of apramycin. Therefore, the methyl donor function of glycine is proposed to be involved in the methionine cycle but methionine itself was proposed to inhibit the methylation and methyl transfer processes as previously reported for the case of rapamycin. The ¹⁵N NMR spectra of [2-¹³C,¹⁵N]serine labeled apramycin indicated that serine may also act as a limiting precursor contributing to the ―NH₂ substituents of apramycin.     

Two complexes at the site of microtubule nucleation

<正>Cortical microtubule(MT)arrays are dynamic filamentous structures that are essential for cell differentiation and development in plants.However,the molecular mechanisms that control the organization of cortical MT arrays are not well understood.Early studies have revealed that the formation of cortical MT arrays involves MT nucleation on existing cortical MTs.The growth of new MTs follows the polarity of existing MTs and the orientation of new MTs is either in parallel with extant MTs or at a small angle(about40 degree)to the extant MTs[1].Nucleation machinery appears to be conserved between animals and plants in     

Interaction between interstitial water and sediment in two cores of Lac Léman,Switzerland

The pore fluids of the sediments collected at the deepest point of Lac Léman (Switzerland) are supersaturated with respect to vivianite and siderite. In the presence of sulphide, the iron solubility is controlled entirely by the amorphous iron sulphides. As the iron (II) becomes dominant, the formation of siderite occurs and evidence of this, in the solid phase, can be obtained by the use of M?ssbauer spectroscopy and some sequential chemical extractions. The amount of ‘siderite iron’ decreases from about 10% near the sediment surface to a few percent in the lower levels of the sediment (<10 cm). Evidence for vivianite formation could not be obtained even in the lower layers, despite the precautions taken to avoid oxidation. Although the trace metal behaviour in the solid phase is well correlated with the iron and manganese, availability in the pore fluid is dependent on the adsorption on, or co-precipitation with, finely dispersed colloids, which pass through a 0.45 μg filter. Trace metal concentrations in pore fluid were not directly related to total elemental concentrations in the solid phase, and did not reflect cumulative trends associated with anthropogenic enrichment.     

Inhibition of associative long-term depression by activation of β-adrenergic receptors in rat hippocampal CA1 synapses

The aim of this study was to investigate the role of β-adrenergic receptors in modulating associative long-term depression (LTD) at CA1 synapses in rat hippocampal slices. Standard extracellular electrophysiological techniques were employed to record field excitatory post-synaptic potential (fEPSP) activity and to induce associative LTD. Two independent Schaffer collateral pathways were elicited in hippocampal CA1 areas. In one (weak) pathway, the stimulating intensity was adjusted to elicit small fEPSP activity (20–30% of the maximum response). In contrast, 80–90% of the maximum response was evoked in the other (strong) pathway. Associative LTD of weak pathway could be induced by paired stimulation of weak and the strong pathways, repeated 100 times at 0.167 Hz. The associative LTD of weak pathway was NMDA receptor- and phophatase 2B dependent, because bath application of 50 μM D, L-AP5 or 10 μM cypermethrin blocked its induction. Bath application of 1 μM isoproterenol inhibited associative LTD, and this effect was blocked by timolol, suggesting the involvement of β-adrenergic receptors. The inhibitory effect of β-adrenergic receptors on LTD induction was blocked in slices pretreated with inhibitors of protein kinase A and mitogen-activated protein kinase, suggesting that these signal cascades are downstream effectors following activation of β-adrenergic receptors. Nevertheless, bath application of timolol or cypermethrin alone did not have significant effect on associative LTD induction, suggesting neither endogenous function of β-adrenergic receptor nor endogenous PKA activity does have a role in associative LTD induction.     

Effects of environmental factors on gross caloric values of three life-forms aquatic plants on the Qinghai-Xizang Plateau,China北大核心CSCD

Aims Gross caloric value (GCV) reflected plants' capability of converting solar energy. It provided a reliable indicator of plants' adaptations to environments in perspective of energy conversion and fixation. The aims of this study were (1) to illustrate the characteristics of GCV of aquatic plants on the Qinghai-Xizang Plateau, (2) to explore the geographical and environmental patterns and (3) to discuss the underlying mechanisms in forming the patterns. Methods In July and August 2015, we collected 533 samples of aquatic plants' leaves in 143 field sites on the Qinghai-Xizang Plateau, and measured their GCV using SDACM-4000 oxygen bomb calorimeter. Together with mean annual temperature (MAT) of climatic factor and properties of water body, this study compared the differences of GCV among submerged, emergent and floating-leaved plants by analysis of variance (ANOVA) and Tukey's HSD. We further regressed GCV of submerged and emergent plants against geographical and climatic factors and properties of water body by simple regression to explore the relative effects of environmental factors on GCV. Important findings On the Qinghai-Xizang Plateau, the mean GCV was (15.95 ± 3.90) kJ·g-1. Among the three life forms, the rank of GCV was the emergent plants (18.10 kJ·g-1) > the floating-leaved plants (16.77 kJ·g-1) > the submerged plants (14.31 kJ·g-1). With an increasing latitude, the GCV of emergent and submerged plants increased. Only GCV of emergent plants decreased with increasing altitude and temperature. The GCV of emergent and submerged plants increased with increased water salinity. Dissolved oxygen had significant negative effects on emergent plants, while pH value had no significant effects.     

“Glial inhibition” of memory in Alzheimer's disease

<正>Two recent studies on Nature Medicine and Nature Communications reported the unusual roles of astrocytes in the brain,that is,release gamma-aminobutyric acid(GABA)and impair hippocampal memory in Alzheimer’s disease(AD).AD represents one common form of neurodegenerative diseases,and is characterized by progressive dementia.The pathological feature of an AD brain includes the appearance     

Effects of laminin glycopeptides on metastasis—related behaviors of cancer cells

Our previous reports have shown that lamininglycopeptides (LN-GPs),the total glycopeptides prepared from laminin (LN),can prevent the experimental lung metastasis and liver metastasis of mouse cancer cells.In order to explore the anti-metastatic mechanism of LN-GPs,we studied the effects of LN-GPs on metastasisrelated behaviors of cancer cells in vitro.LN-GPs did not affect cell survival.However,LN-GPs inhibited cell attachment and spreading of S180 cells on LN-and Matrigelsubstrate in dose-dependent and time-dependent manners.Moreover,inhibition of cell attachment and spreading on Matrigel substrates were much greater on Matrigel substrate than on LN substrate.In the gresence of LN-GPs,S180 cells on LN substrate changed from a flattened polygonal shape to a round one,the migration of S180 cells on LN substrate decreased,and the number of a highly invasive human pulmonary giant carcinoma PG cells invading Matrigel filter in a Boyden chamber was reduced.LN-GPs thus have multiple inhibitory effects on cancer metastasisrelated behaviors.     

Effect of phytohormones on plant regeneration from callus ofGladiolus cultivar “Jenny Lee”

Summary Callus capable of plant regeneration was initiated at a higher frequency from the basal leaves of in vitro plants (70% explants) as compared to cormel slices (30% explants) when cultured on medium containing various concentrations of auxin. The greatest number of plants were regenerated from 4-mo.-old callus (112 plants/g fresh weight callus) cultured on medium containing 10 mg/liter (53.8μM) 1-napthaleneacetic acid. The addition of 2 mg/liter (9.3μM) kinetin to a Murashige and Skoog’s basal salts regeneration medium resulted in an average two- to three-fold increase in the number of plants regenerated compared to regeneration on medium without hormones. Ten months after callus initiation, all callus maintained on auxin-supplemented media showed a drastic reduction in its capacity to regenerate plants. Ten-month-old callus maintained on dicamba regenerated the greatest number of plants (14 to 23 plants regenerated per gram fresh weight callus) as compared to callus maintained 10 mo. on medium containing 1-napthaleneacetic acid or 2,4-dichlorophenoxyacetic acid. Cormel slices cultured on cytokinin-supplemented media formed small amounts of callus which regenerated up to 19 plants per cormel slice within 1 to 2 mo. after the cormel slice had been placed on either 10 mg/liter (49.2μM) N⁶-2-isopentenyladenosine or 1 mg/liter (4.4μM) 6-benzylaminopurine.     

Influence of pegylated interferon-α therapy on plasma levels of citrulline and arginine in melanoma patients

Summary. The aim of this study was to evaluate the effect of pegylated interferon-alpha (PEG-IFN-α) on the plasma citrulline/arginine ratio, regarded as an index of nitric oxide (NO) synthesis, in patients with high-risk melanoma. Forty patients were randomly assigned to either PEG-IFN-α treatment (n = 22) or to observation only (control group, n = 18). The treatment group received 6 μg PEG-IFN-α/kg once a week during 8 weeks, followed by a maintenance dose of 3 μg/kg/wk. Blood was collected at different time points, plasma concentrations of citrulline and arginine were measured and the ratio of citrulline/arginine was calculated. Patients treated with PEG-IFN-α showed a significant decrease in the concentrations of citrulline and in the citrulline/arginine ratio during the whole study period, both compared to baseline values and to the control group. The data suggest that therapy with PEG-IFN-α results in a marked decrease in the synthesis of NO in melanoma patients.