肾脏疾病检测的现状与应用

肾脏疾病是临床上常见而又十分严重的疾病,若不能及时发现,常引起肾衰,危及生命。随着对肾脏病的研究,肾脏疾病的检测方法也有了很大进步,建立肾损伤早期检测体系成为当务之急,目前这一体系主要包括肾小球早期损伤标志物：尿微量白蛋白(mAlb)和尿转铁蛋白(Tf);肾小管早期损伤标记物：肾小管上皮细胞的各种酶(统称尿酶)、各段肾小管脱落的抗原性物质和低分子量蛋白(LMWP);肾小球滤过率的标志物：胱氨酸蛋白酶抑制剂C(Cystatin C)。     

A strategy for the production of soluble human senescence marker protein-30 in Escherichia coli

Senescence marker protein-30 (SMP30) has been reported to hydrolyze diisopropyl fluorophosphate (DFP), a surrogate compound of chemical warfare nerve agents. Thus, SMP30 has the potential to be useful as a prophylactic against chemical warfare nerve agent toxicity. Our efforts to generate human SMP30 in bacteria using a variety of expression vectors invariably resulted in insoluble and inactive preparations. In this study, properly folded and active recombinant human SMP30 (rHuSMP30) was produced in Escherichia coli by coexpressing it with molecular chaperones in a combined strategy. The coexpression of rHuSMP30 with GroES/GroEL/Tf at 15 °C, combined with the addition of a membrane fluidizer, increased osmolytes, and a two-step expression resulted in the highest enhancement of solubility and DFPase activity. Our results pave the way for exploring the use of rHuSMP30 against organophosphate and nerve agent toxicity.     

Chemical synthesis of febrifugine and analogues

The quinazolinone-containing 2,3-disubstituted piperidines febrifugine and isofebrifugine have been the subject of significant research efforts since their occurrence in Dichroa febrifuga and their anti-malarial actions were first described in the late 1940s. Subsequently they have also been shown to be present in other plants belonging to the hydrangea family and various analogues of febrifugine have been prepared in attempts to tune biological properties. The most notable analogue is termed halofuginone and a substantial body of work now demonstrates that this compound possesses potent human disease relevant activities. This review focuses on the literature associated with efforts dedicated towards uncovering the structures of febrifugine and isofebrifugine, the development of practical methods for their synthesis and the syntheses of structural analogues.     

Assessing the potential of short rotation coppice (SRC) for cleanup of radionuclide-contaminated sites

A small-scale greenhouse investigation was undertaken using Goat willow (Salix caprea) and aspen (Populus tremula) to evaluate the potential of short rotation coppice for remediation of 137Cs- and 90Sr-contaminated sites. Results showed that both species were able to accumulate these radionuclides from a representative disposal soil (aged) and a spiked soil S. caprea accumulating greater levels of 137Cs than P. tremula, with no difference between species for 90Sr accumulation. For each radionuclide, the distribution in both species was similar, with 137Cs accumulation greatest in the roots, whereas 90Sr accumulation was greatest in the leaves. It was also evident that the soil-to-plant transfer factor (Tf) values for 90Sr were greater than for 137Cs, agreeing with differences in the reported bioavailailablity of these radionuclides in soil Based on the Tf values for S. caprea (conservative), estimated remediation times were 92 and 56 yr, for 137Cs and 90Sr, respectively. It is suggested that the selection of Salix species grown in a system of SRC provides a significant opportunity for removal of both 137Cs and 90Sr, primarily due to its higher biomass production. However, for 137Cs phytoremediation investigations into the appropriate use of soil amendments for increasing bioavailability are required.     

新疆伊犁河鲫鱼遗传多样性初步研究

为了解我国西北地区野生鲫鱼的遗传多样性,鲫鱼样品从新疆伊梨河中采用小型拖网捕获。通过解剖观察性腺鉴定性别;采用碘化丙啶（PI）染色,经流式细胞仪测定血细胞核DNA含量;采用非变性聚丙烯酰胺凝胶电泳,考马斯亮蓝染色分析血清转铁蛋白多态性。结果表明：新疆伊梨河鲫鱼群体为具雌、雄的两性个体的群体;伊犁河鲫鱼血细胞核DNA平均含量为(5.315±0.215) pg/个细胞核,血细胞核DNA含量约为二倍体彩鲫DNA含量的1.53倍,与银鲫血细胞核DNA含量相当;在所采集的鲫鱼样品中共发现9种转铁蛋白表现型, 由7个等位基因调控,等位基因频率依次为Tf a0.063、Tf b0.063、Tf f0.095、Tf g0.169、Tf c0.174、Tf e0.175和Tf d0.270。基因型频率分别为Tf cd0.043、Tf cdf0.043、Tf abdg0.043、Tf def 0.087、Tf ce0.13、Tf de0.13、Tf df0.13、Tf abeg0. 13和Tf cdg0.26。综合分析,伊犁河现存野生鲫鱼为银鲫,且具有两性融合生殖能力。伊犁河鲫鱼表现出的遗传特性可能与该特定水环境有关。     

Suppression of dynamin GTPase activity by sertraline leads to inhibition of dynamin-dependent endocytosis

Dynamin (Dyn) 1 plays a role in recycling of synaptic vesicles, and thus in nervous system function. We previously showed that sertraline, a selective serotonin reuptake inhibitor (SSRI), is a mixed-type inhibitor of Dyn 1 with respect to both GTP and l-α-phosphatidyl-l-serine (PS) in vitro, and we suggested that it may regulate the neurotransmitter transport by modulating synaptic vesicle endocytosis via inhibition of Dyn 1 GTPase. Here, we investigated the effect of sertraline on endocytosis of marker proteins in human neuroblastoma SH-Sy5Y cells and HeLa cells. Sertraline inhibited endocytosis in both cell lines. Western blotting showed that SH-Sy5Y expresses Dyn 1 and Dyn 2, while HeLa expresses only Dyn 2. GTPase assay showed that sertraline inhibited Dyn 2 as well as Dyn 1. Therefore, the effect of sertraline on endocytosis was mediated by Dyn 2, at least in HeLa cells, as well as by Dyn 1 in cell lines that express it. Moreover, the inhibition mechanism of transferrin (Tf) uptake by sertraline differed from that in cells expressing Dyn 1 K44A, a GTP binding-defective variant, and sertraline did not interfere with the interaction between Dyn 1 and PS-liposomes.     

H-bonding networks of the distal residues and water molecules in the active site of Thermobifida fusca hemoglobin

The ferric form of truncated hemoglobin II from Thermobifida fusca (Tf-trHb) and its triple mutant WG8F-YB10F-YCD1F at neutral and alkaline pH, and in the presence of CN⁻ have been characterized by resonance Raman spectroscopy, electron paramagnetic resonance spectroscopy, and molecular dynamics simulations. Tf-trHb contains three polar residues in the distal site, namely TrpG8, TyrCD1 and TyrB10. Whereas TrpG8 can act as a potential hydrogen-bond donor, the tyrosines can act as donors or acceptors. Ligand binding in heme-containing proteins is determined by a number of factors, including the nature and conformation of the distal residues and their capability to stabilize the heme-bound ligand via hydrogen-bonding and electrostatic interactions. Since both the RR Fe–OH⁻ and Fe–CN⁻ frequencies are very sensitive to the distal environment, detailed information on structural variations has been obtained. The hydroxyl ligand binds only the WT protein giving rise to two different conformers. In form 1 the anion is stabilized by H-bonds with TrpG8, TyrCD1 and a water molecule, in turn H-bonded to TyrB10. In form 2, H-bonding with TyrCD1 is mediated by a water molecule. Unlike the OH⁻ ligand, CN⁻ binds both WT and the triple mutant giving rise to two forms with similar spectroscopic characteristics. The overall results clearly indicate that H-bonding interactions both with distal residues and water molecules are important structural determinants in the active site of Tf-trHb. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.     

Characterization of the Interaction between Diferric Transferrin and Transferrin Receptor 2 by Functional Assays and Atomic Force Microscopy

Transferrin receptor 2 (TfR2), a homologue of the classical transferrin receptor 1 (TfR1), is found in two isoforms, α and β. Like TfR1, TfR2α is a type II membrane protein, but the β form lacks transmembrane portions and therefore is likely to be an intracellular protein. To investigate the functional properties of TfR2α, we expressed the protein with FLAG tagging in transferrin-receptor-deficient Chinese hamster ovary cells. The association constant for the binding of diferric transferrin (Tf) to TfR2α is 5.6 × 10⁶ M^− 1, which is about 50 times lower than that for the binding of Tf to TfR1, with correspondingly reduced rates of iron uptake. Evidence for Tf internalization and recycling via TfR2α without degradation, as in the TfR1 pathway, was also found. The interaction of TfR2α with Tf was further investigated using atomic force microscopy, a powerful tool used for investigating the interaction between a ligand and its receptor at the single-molecule level on the living cell surface. Dynamic force microscopy reveals a difference in the interactions of Tf with TfR2α and TfR1, with Tf-TfR1 unbinding characterized by two energy barriers, while only one is present for Tf-TfR2. We speculate that this difference may reflect Tf binding to TfR2α by a single lobe, whereas two lobes of Tf participate in binding to TfR1. The difference in the binding properties of Tf to TfR1 and TfR2α may help account for the different physiological roles of the two receptors.     

Rhipicephalus (Boophilus) microplus: distinct acute phase proteins vary during infestations according to the genetic composition of the bovine hosts, Bos taurus and Bos indicus

Tick bites may trigger acute phase responses. Positive and negative acute phase proteins were measured in infested cattle genetically resistant and susceptible to ticks. During heavier infestations levels of haptoglobin increased significantly in susceptible bovines; levels of serum amyloid A increased in resistant bovines; levels of alpha-1-acid glycoprotein decreased significantly in resistant bovines; levels of transferrin decreased significantly in susceptible bovines. In conclusion, tick infestations trigger acute phase responses and enhancement of specific acute phase proteins differs according to the genetic composition of hosts. Acute phase proteins may constitute useful biological signatures for monitoring the stress induced by tick infestations.     

Manganese neurotoxicity: A bioinorganic chemist’s perspective

Manganese is an essential metal for life, yet chronic exposure to this metal can cause a neurodegenerative disease named manganism, with symptoms that resemble Parkinson’s disease. Mn accumulates in the striatum and damages this brain structure that controls motor function; however, the molecular mechanisms underlying this neurodegenerative disease are poorly understood. In this short review, a summary of the current knowledge on the mechanisms involved in Mn neurotoxicity is given, with a special emphasis on the features that suggest specific protein-manganese interactions. The mechanisms of Mn uptake into the brain are discussed, displaying its similarities to Fe metabolism. Cellular trafficking of Mn is also reviewed, pointing out at its connection to Ca homeostasis, and its relevance for understanding Mn-induced neuronal death. The main purpose of this review is to provide a glimpse of an unexplored bioinorganic facet of a Mn-induced neurodegenerative disease.