Expression profile of carbonic anhydrases in articular cartilage

Carbonic anhydrases (CAs), which catalyze the reversible reaction of carbonate hydration, are important for cartilage homeostasis. The full spectrum of CA activity of all 13 isoenzymes in articular cartilage is unknown. This study quantified the mRNA profile of CAs in rat articular cartilage, using quantitative polymerase chain reactions. Among the 13 functional CAs, CAs II, III, Vb, IX, XII and XIII were significantly expressed at mRNA level by the chondrocytes in articular cartilage. To verify these significantly expressed CAs in articular cartilage at protein level, immunohistochemistry was performed. While CAs III, Vb and XII distributed in the full-thickness of cartilage, including the calcified zone of cartilage, CA II was mainly localized in the proliferative zone of cartilage. CA IX was limited in the superficial zone of cartilage and CA XIII expressed in the superficial and partially mid zone. These results provide a framework for understanding individual CAs as well as the integrated CA family in cartilage biology, including matrix mineralization.     

Slow decomposition of very fine roots and some factors controlling the process: a 4-year experiment in four temperate tree species

Background and aims

Nitrate leaching from intensively cropped soils represents a huge environmental problem. In order to diversify the range of nitrogen management strategies, this investigation is focused on the effects of ribwort plantain, Plantago lanceolata L., and its allelochemicals on soil N mineralization.

Methods

High-performance liquid chromatography was used in this study for phytochemical analysis of the major allelochemicals aucubin, catalpol, and verbascoside. Soil incubation experiments demonstrated a significant suppression of soil N mineralization caused by the incorporation of the iridoid glycoside (IG) aucubin, leaf material of two varieties (P. lanceolata cv. Libor and cv. Arterner), and an aqueous extract of P. lanceolata leaves.

Results

Throughout the growing season, the two varieties conspicuously differed in aucubin and verbascoside contents as well as in leaf dry weight. In soil incubation experiments, incorporated leaf material of both varieties affected long-term low soil nitrate concentrations. Experimental aucubin application resulted in an inhibitory effect on soil N mineralization. This was not true for the IG catalpol. Furthermore, we observed a negative relationship between IG concentrations and inorganic soil nitrogen concentrations when the soil was incubated with aqueous P. lanceolata leaf extract of different concentrations.

Conclusion

This study enforced the hypothesis that allelochemicals of P. lanceolata have an active role in a suppression effect on soil N mineralization. Further research may be necessary to investigate the specific effects of P. lanceolata allelochemicals on the nitrogen cycle.     

沙漠结皮中藻类生态的研究

笔者对宁夏中卫沙坡头干旱区沙漠表面结皮中藻类进行了为时１０个月（１９９１年５月－１９９２年２月）的定量和定性研究、结果表明：共出现１３个属的藻类,其中蓝藻５属,绿藻６属（包括１个未鉴定出的属）,硅藻２属。运用稀释平板法得到藻类生物量平均为８．１１７×１０￣４ｃｅｌｌｓ／ｇ　Ｄ．Ｓ．根据结皮土壤的理化性质（包括ｐＨ、含水量、电导率、水溶性Ｋ￣＋、Ｎａ￣＋、Ｃａ￣（２＋）和Ｍｇ￣（２＋）的量、交换性盐基总量、全磷量、有机质和凯氏氮）及气候条件（气温、降雨量和土壤温度）分别与藻类生物量的简单相关系数可知影响生物量比较显著的因子有交换性盐基总量（ｒ＝０．６８３）、降雨量（ｒ＝０．７１２）、有机质含量（ｒ＝０．５８４）和水溶性Ｎａ￣＋（ｒ＝０．５８６）。进一步运用逐步回归分析的方法,结果表明影响藻类生物量最显著的相关因子是水溶性Ｍｇ￣（２＋）和降雨量（Ｒ￣２＝７８．７４％）。     

Host E3 ligase HUWE1 attenuates the proapoptotic activity of the MERS-CoV accessory protein ORF3 by promoting its ubiquitin-dependent degradation

With the outbreak of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), coronaviruses have begun to attract great attention across the world. Of the known human coronaviruses, however, Middle East respiratory syndrome coronavirus (MERS-CoV) is the most lethal. Coronavirus proteins can be divided into three groups: nonstructural proteins, structural proteins, and accessory proteins. While the number of each of these proteins varies greatly among different coronaviruses, accessory proteins are most closely related to the pathogenicity of the virus. We found for the first time that the ORF3 accessory protein of MERS-CoV, which closely resembles the ORF3a proteins of severe acute respiratory syndrome coronavirus and SARS-CoV-2, has the ability to induce apoptosis in cells in a dose-dependent manner. Through bioinformatics analysis and validation, we revealed that ORF3 is an unstable protein and has a shorter half-life in cells compared to that of severe acute respiratory syndrome coronavirus and SARS-CoV-2 ORF3a proteins. After screening, we identified a host E3 ligase, HUWE1, that specifically induces MERS-CoV ORF3 protein ubiquitination and degradation through the ubiquitin–proteasome system. This results in the diminished ability of ORF3 to induce apoptosis, which might partially explain the lower spread of MERS-CoV compared to other coronaviruses. In summary, this study reveals a pathological function of MERS-CoV ORF3 protein and identifies a potential host antiviral protein, HUWE1, with an ability to antagonize MERS-CoV pathogenesis by inducing ORF3 degradation, thus enriching our knowledge of the pathogenesis of MERS-CoV and suggesting new targets and strategies for clinical development of drugs for MERS-CoV treatment.     

Comparative chemical composition of the essential oils obtained by microwave-assisted hydrodistillation and hydrodistillation from Agrimonia pilosa LEDEB. Collected in three different regions of China

Conventional hydrodistillation (HD) and microwave-assisted hydrodistillation (MAHD) were performed to obtain the volatile oils of Agrimonia pilosa Ledeb. harvested in three different regions of China, which were subsequently characterized by GC-FID and GC/MS analyses. Compared with HD, MAHD was advantageous in terms of energy savings and extraction time (60 vs. 240?min for MAHD and HD, resp.). The chemical composition varied among the different oils obtained, and the variations in the contents of the main constituents of the oils were irregular. Hence, these variations affected both the quantity and composition of the oils. The oil yields (0.15-0.21%) were affected by the method of extraction and the region of harvest, with the maximum amount of oil obtained by MAHD for the plants collected in Hubei (HB) and the minimum yield obtained by HD for the plants from Zhejing (ZJ). Hexadecanoic acid constituted the major compound of the essential oils, with the highest content found in the oil obtained by HD for plants from HB (41.18%) and the lowest one found in the oil obtained by MAHD from plants from ZJ (11.83%). Microwave irradiation did not adversely affect the composition of the essential oils. The findings show that MAHD is a modern, green, and fast technology.     

High expression of lactotriaosylceramide, a differentiation-associated glycosphingolipid, in the bone marrow of acute myeloid leukemia patients

Glycosphingolipids (GSLs) are information-bearing biomolecules that play critical roles in embryonic development, signal transduction and carcinogenesis. Previous studies indicate that certain GSLs are associated with differentiation in acute myeloid leukemia (AML) cells. In this study, we collected bone marrow samples from healthy donors and AML patients and analyzed the GSL expression profiles comprehensively using electrospray ionization linear ion-trap mass spectrometry. The results showed that AML patients had higher expression of the GSL lactotriaosylceramide (Lc3), GM3 and neolactotetraosylceramide (nLc4) in their bone marrow than did the healthy donors (P < 0.05), especially the M1 subtype of AML. To further explore the molecular mechanisms of Lc3, we examined the expression of the Lc3 synthase β1,3-N-acetylglucosaminyltransferase5 (β3Gn-T5) and found that the bone marrow samples of AML patients had 16-fold higher expression of β3Gn-T5 than those of healthy donors (P < 0.05). Our results suggest that AML-associated GSLs Lc3, GM3 and nLc4 are possibly involved in initiation and differentiation of AML.     

Protective Effect of Naringenin Against Lead-Induced Oxidative Stress in Rats

Oxidative stress is thought to be involved in lead-induced toxicity. The aim of this study was to investigate the possible protective role of naringenin on lead-induced oxidative stress in the liver and kidney of rats. In the present investigation, lead acetate (500 mg Pb/L) was administered orally for 8 weeks to induce hepatotoxicity and nephrotoxicity. The levels of hepatic and renal markers such as alanine aminotransferase, aspartate aminotransferase, urea, uric acid, and creatinine were significantly (P < 0.05) increased following lead acetate administration. Lead-induced oxidative stress in liver and kidney tissue was indicated by a significant (P < 0.05) increase in the level of maleic dialdehyde and decreased levels of reduced glutathione, superoxide dismutase, catalase, and glutathione peroxidase. Naringenin markedly attenuated lead-induced biochemical alterations in serum, liver, and kidney tissues (P < 0.05). The present study suggests that naringenin shows antioxidant activity and plays a protective role against lead-induced oxidative damage in the liver and kidney of rats.     

Microbial diversity and biomineralization in low-temperature hydrothermal iron-silica-rich precipitates of the Lau Basin hydrothermal field

Iron-silica-rich low-temperature hydrothermal precipitates were collected from the CDE hydrothermal field located at the East Lau Spreading Center. Phylogenetic analysis showed that the precipitates were dominated by the members of α-proteobacteria and marine group I archaea. Ultrastructural analysis suggested the bacteriogenic origin of the iron-silica-rich deposits. Distinctive biosignatures detected included straight filaments, helical stalks and curved irregular filaments, which were similar in appearance to those structures excreted by the known iron-oxidizing genera Leptothrix spp., Gallionella spp. and Mariprofundus spp. 16S rRNA gene analysis confirmed the presence of neutrophilic iron-oxidizing bacteria with the detection of phylotypes clustering with Gallionella spp. and the proposed ζ-proteobacteria class. Mineralogy and bulk geochemical analyses showed that the precipitates were dominated by amorphous silica with low amounts of iron. Based on microbiological, geochemical and mineralogical analyses, we conclude that silicification was a common process and microbial cells and related ultrastructures likely acted as nucleation templates for silica precipitation in the CDE hydrothermal field.     

Inhibition of hepatocyte nuclear factor 1β contributes to cisplatin nephrotoxicity via regulation of nf-κb pathway

Cisplatin nephrotoxicity has been considered as serious side effect caused by cisplatin-based chemotherapy. Recent evidence indicates that renal tubular cell apoptosis and inflammation contribute to the progression of cisplatin-induced acute kidney injury (AKI). Hepatocyte nuclear factor 1β (HNF1β) has been reported to regulate the development of kidney cystogenesis, diabetic nephrotoxicity, etc However, the regulatory mechanism of HNF1β in cisplatin nephrotoxicity is largely unknown. In the present study, we examined the effects of HNF1β deficiency on the development of cisplatin-induced AKI in vitro and in vivo. HNF1β down-regulation exacerbated cisplatin-induced RPTC apoptosis by indirectly inducing NF-κB p65 phosphorylation and nuclear translocation. HNF1β knockdown C57BL/6 mice were constructed by injecting intravenously with HNF1β-interfering shRNA and PEI. The HNF1β scramble and knockdown mice were treated with 30 mg/kg cisplatin for 3 days to induce acute kidney injury. Cisplatin treatment caused increased caspase 3 cleavage and p65 phosphorylation, elevated serum urea nitrogen and creatinine, and obvious histological damage of kidney such as fractured tubules in control mice, which were enhanced in HNF1β knockdown mice. These results suggest that HNF1β may ameliorate cisplatin nephrotoxicity in vitro and in vivo, probably through regulating NF-κB signalling pathway.