磁共振动态对比增强联合血清TSGF、ICTP、ALP对骨肿瘤良恶性鉴别和骨恶性肿瘤治疗后的疗效评估价值

摘要 目的：探讨磁共振动态对比增强（DCE-MRI）联合血清肿瘤相关物质（TSGF）、I型胶原羧基吡啶末端肽（ICTP）、碱性磷酸酶（ALP）对骨肿瘤良恶性鉴别和骨恶性肿瘤治疗后的疗效评估价值。方法：选择2020年12月至2022年4月本院收治的骨肿瘤患者163例为研究对象，根据骨肿瘤良恶性分为良性组（74例）和恶性组（89例），恶性组治疗后根据实体肿瘤疗效评价标准分为疗效良好组和疗效不良组，比较良性组与恶性组、疗效良好组与疗效不良组容量运转常数（Ktrans）、速率常数（Kep）、血管外细胞外间隙容积分数（Ve）及1分钟内初始曲线下面积（iAUC）、TSGF、ICTP、ALP，分析Ktrans、Kep、Ve、iAUC与血清TSGF、ICTP、ALP的相关性，采用受试者工作特征（ROC）曲线分析各指标对骨肿瘤良恶性的预测价值。结果：不同组间Ktrans、Kep、iAUC、TSGF、ICTP、ALP比较，良性组低于恶性组（P＜0.05），疗效良好组低于疗效不良组（P＜0.05）；DCE-MRI定量参数中的Ktrans、Kep、iAUC与血清TSGF、ICTP、ALP呈正相关（P＜0.05）；Ktrans、Kep、iAUC、TSGF、ICTP、ALP及联合预测骨肿瘤良恶性的曲线下面积（AUC）分别为0.794、0.804、0.744、0.747、0.773、0.828和0.986，各项指标联合预测骨肿瘤良恶性的AUC大于各指标单独预测。结论：DCE-MRI定量参数Ktrans、Kep、iAUC联合血清TSGF、ICTP、ALP对骨肿瘤良恶性具有较高的鉴别价值，此外Ktrans、Kep、iAUC、TSGF、ICTP、ALP越高，恶性骨肿瘤患者治疗后的临床疗效越差。     

Phytoplankton and bacterial alkaline phosphatase activities in relation to phosphate and DOP availability within the Gironde plume waters (Bay of Biscay)

Previous studies conducted on the continental shelf in the Southeast Bay of Biscay influenced by Gironde waters (one of the two largest rivers on the French Atlantic coast) showed the occurrence of late winter phytoplankton blooms and phosphorus limitation of algal growth thereafter. In this context, the importance of dissolved organic phosphorus (DOP) for both algae and bacteria was investigated in 1998 and 1999 in terms of stocks and fluxes. Within the mixed layer, although phosphate decreased until exhaustion from winter to spring, DOP remained high and phosphate monoesters made up between 11 to 65% of this pool. Total alkaline phosphatase activity (APA, V_max) rose gradually from winter (2-8 nM h⁻¹) to late spring (100-400 nM h⁻¹), which was mainly due to an increase in specific phytoplankton (from 0.02 to 3.0 nmol μgC⁻¹ h⁻¹) and bacterial APA (from 0.04 to 4.0 nmol μgC⁻¹ h⁻¹), a strategy to compensate for the lack of phosphate. At each season, both communities had equal competitive abilities to exploit DOP but, taking into account biomass, the phytoplankton community activity always dominated (57-63% of total APA) that of bacterial community (9-11%). The dissolved APA represented a significant contribution. In situ regulation of phytoplanktonic APA by phosphate (induction or inversely repression of enzyme synthesis) was confirmed by simultaneously conducted phosphate-enrichment bioassays. Such changes recorded at a time scale of a few days could partly explain the seasonal response of phytoplankton communities to phosphate depletion.     

Effects of organic and inorganic nitrogen compounds on the activity of bacterial alkaline phosphatase

The stimulation of bacterial alkaline phosphatase activity (APA) by inorganic and organic nitrogen compounds was investigated in the southern Baltic Sea monthly between February and August 2001, by adding albumin, casein, leucine, ammonium, nitrate, ammonium + glucose or nitrate + glucose to 0.8 µm filtered seawater. The following questions were addressed: (1) Are there seasonal changes in the stimulation of APA by these substances?; (2) Does nitrogen alone stimulate this activity or only in combination with organic carbon?; (3) Is there a relationship between ambient nutrient concentrations and the degree of stimulation? The addition of the mentioned compounds stimulated the APA in bacteria to a high degree, however, there were seasonal variations. Stimulation was low in February and March but high from May to August when the stimulation, e.g., by ammonium + glucose, was up to 6000-fold higher compared with February. In most experiments, the addition of the amino acid leucine and of inorganic nitrogen alone resulted in an inhibition of the bacterial APA. A relationship between ambient nutrient concentrations and the stimulation of the bacterial APA was only observed for albumin, which correlated negatively with dissolved inorganic nitrogen (DIN) and phosphate concentrations and for casein, which correlated only with DIN. The results indicate that the regulation of bacterial APA and the DOP degradation can be significantly influenced by the availability of nitrogen and organic carbon.     

Ectoenzymes in Prorocentrum minimum

Ectoenzymes, or enzymes associated with the cell-surface or periplasmic space, play an important role in organic matter cycling by rendering certain forms of dissolved organic matter bioavailable. Ectoenzyme activities may thereby help meet the nutritional demands of harmful algae such as Prorocentrum minimum. The activities of two ectoenzymes; leucine aminopeptidase and alkaline phosphatase, have been studied in axenic cultures of P. minimum. Leucine aminopeptidase releases non-polar amino acids such as leucine from the N-terminus of polypeptides, whereas alkaline phosphatase is an enzyme that is able to hydrolyze phosphate from phosphomonoesters. P. minimum alkaline phosphatase is the better studied of the two ectoenzymes and its characteristics are reviewed herein. Future research on P. minimum physiology will benefit from a growing suite of tools available for assessing the activity of alkaline phosphatase and other ectoenzymes in field populations and ultimately the work done with P. minimum will be useful for studies of other harmful species.     

Purification and characterization of thermo-labile alkaline phosphatase from an Antarctic psychrotolerant Bacillus sp. P9

A psychrotolerant Bacillus sp. from Antarctica produced an alkaline phosphatase in the culture supernatant. The strain showed 98.4% 16s rDNA sequence identity with Bacillus sphaericus. The 76 kDa protein was purified 11.1-fold showing alkaline phosphomonoesterase activity. Enzyme was optimally produced at 25 °C and pH 7.0. This cold active alkaline phosphatase is heat labile and gets completely inactivated at 60 °C in 50 min and is active in broad pH range.     

Formation of a molten globule like state in bovine serum albumin at alkaline pH

Little work has been done to understand the folding profiles of multi-domain proteins at alkaline conditions. We have found the formation of a molten globule-like state in bovine serum albumin at pH 11.2 with the help of spectroscopic techniques; like far and near ultra-violet circular dichroism, intrinsic and extrinsic fluorescence spectroscopy. Interestingly, this state has features similar to the acid-denatured state of human serum albumin at pH 2.0 reported by Muzammil et al. (Eur J Biochem 266:26–32, 1999). This state has also shown significant increase in 8-anilino-1-naphthalene-sulfonate (ANS) binding in compare to the native state. At pH 13.0, the protein seems to acquire a state very close to 6 M guanidinium hydrochloride (GuHCl) denatured one. But, reversibility study shows it can regain nearly 40% of its native secondary structure. On the contrary, tertiary contacts have disrupted irreversibly. It seems, withdrawal of electrostatic repulsion leave room for local interactions, but disrupted tertiary contacts fail to regain their original states.     

Enhancement of the activity and alkaline pH stability of <Emphasis Type="Italic">Thermobifida fusca</Emphasis> xylanase A by directed evolution

Directed evolution has been used to enhance the catalytic activity and alkaline pH stability of Thermobifida fusca xylanase A, which is one of the most thermostable xylanases. Under triple screened traits of activity, alkaline pH stability and thermostability, through two rounds of random mutagenesis using DNA shuffling, a mutant 2TfxA98 with approximately 12-fold increased k _cat/K _m and 4.5-fold decreased K _m compared with its parent was obtained. Moreover, the alkaline pH stability of 2TfxA98 is increased significantly, with a thermostability slightly lower than that of its parent. Five amino acid substitutions (T21A, G25P, V87P, I91T, and G217L), three of them are near the catalytic active site, were identified by sequencing the genes encoding this evolved enzyme. The activity and stabilizing effects of each amino acid mutation in the evolved enzyme were evaluated by site-directed mutagenesis. This study shows a useful approach to improve the catalytic activity and alkaline pH stability of T. fusca xylanase A toward the hydrolysis of xylan.     

Phosphate and pyrophosphate mediate PKA-induced vascular cell calcification

Vascular calcification is associated with increased cardiovascular risk and occurs by osteochondrogenic differentiation of vascular cells. Many of the same regulatory factors that control skeletal mineralization, including the complex metabolic pathway controlling levels of the activator, inorganic phosphate, and the potent inhibitor, pyrophosphate, also govern vascular calcification. We previously found that the cAMP/PKA signaling pathway mediates in vitro vascular cell calcification induced by inflammatory factors including tumor necrosis factor-alpha 1 and oxidized phospholipids. In this report, we tested whether this signaling pathway modulates phosphate and pyrophosphate metabolism. Treatment of primary murine aortic cells with the PKA activator, forskolin, significantly induced osteoblastic differentiation markers, including alkaline phosphatase (ALP), osteopontin, and osteocalcin as well as the pyrophosphate generator, ectonucleotide-pyrophosphatase/phosphodiesterase-1 (Enpp1) and the pyrophosphate transporter, ankylosis protein, but not the sodium/phosphate cotransporter, Pit-1. In the presence of a substrate for ALP, beta-glycerophosphate, which generates inorganic phosphate, forskolin also enhanced matrix mineralization. Inhibitors of ALP or Pit-1 abrogated forskolin-induced osteopontin expression and mineralization but not forskolin-induced osteocalcin or ALP. These results suggest that phosphate is necessary for PKA-induced calcification of vascular cells and that the extent of PKA-induced calcification is controlled by feedback induction of the inhibitor, pyrophosphate.     

泡囊丛枝(VA)菌根对玉米根际磷酸酶活性的影响

以玉米为材料,利用三室隔网培养方法,研究了缺P土壤上施用植酸和卵磷脂时接种几种菌根真菌(Glomus mosseae, Glmous versiformea, Gigaspora margarita)对根际土壤酸性磷酸酶和碱性磷酸酶活性的影响.玉米生长70d后,收获测定距根表不同距离土壤中的磷酸酶活性.结果表明,接种菌根真菌增加了根际土壤酸性和碱性磷酸酶活性,Gigaspora margarita菌根菌的作用大于其它2个菌根菌.不同P源对磷酸酶活性有明显影响.     

Isolation and Screening of Alkaline Lipase-producing Fungi from Brazilian Savanna Soil

Summary Fifty-nine lipase-producing fungal strains were isolated from Brazilian savanna soil by employing enrichment culture tecniques. An agar plate medium containing bile salts and olive oil emulsion was employed for isolating and growing fungi in primary screening assay. Twenty-one strains were selected by the ratio of the lipolytic halo radius and the colonies radius. Eleven strains were considered good producers under conditions of submerged liquid fermentation (shaken cultures) and solid-state fermentation. The most productive strain, identified as Colletotrichum gloesporioides, produced 27,700 U/l of lipase under optimized conditions and the crude lipase preparation was capable of hydrolysing a broad range of substrates including lard, natural oils and tributyrin.