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1.
Phenylalanine hydroxylase is assumed to be a key enzyme in drosopterin metabolism, but direct in vivo evidence to support this hypothesis is still absent.In the present study, we found a new natural reces-sive purple eye mutant of Drosophila melanogaster, Hnbp, which was a 45-nt insertion mutant in the second exon of Henna.The insertion resulted in a predicted protein with 15 additional amino acids as compared to the wild-type protein.Further analysis of protein structure showed that the predicted mutant protein probably had two more β-sheets, which may cause instability of two α-helices near the catalytic centre of the enzyme in the Biopterin-Hydroxyl binding domain.Hnbp mutant showed eye color defect with decrease of mRNA level, as well as drosopterin content reduction.The drosopterin defect could be fully rescued by expression of wild type Henna in the Hnbp background by GMR-GAL4 UAS-Henna/UAS-Henna:Hnbp/Hnbp transgenic line.All taken together, it can be concluded that the mu-tation in Henna is responsible for drosopterin reduction in mutant Hnbp, which provides key in vivo evidence to support the hypothesis that Henna is involved in drosopterin synthesis.  相似文献   

2.
Proteins like Rafkinase inhibitory protein (RKIP) that serve as modulators of signaling pathways, either by promoting or inhibiting the formation of productive signaling complexes through protein-protein interactions, have been demonstrated to play an increasingly important role in a number of cell types and organisms. These proteins have been implicated in development as well as the progression of cancer. RKIP is a particularly interesting regulator, as it is a highly conserved, ubiquitously expressed protein that has been shown to play a role in growth and differentiation in a number of organisms and can regulate multiple signaling pathways. RKIP is also the first MAP kinase signaling modulator to be identified as playing a role in cancer metastasis, and identification of the mechanism by which it regulates Raf-1 activation provides new targets for theraoeutic intervention.  相似文献   

3.
Summary The dialysed humic acids obtained from a forest Mull by extraction of a diluted solution of sodium carbonate are enzymatically active. It is found by radiorespirometry that the humic acids act on thel-tryptophan carboxyl C14, although thed-tryptophan carboxyl suffers no attack. The methylene group and the indole and benzene nuclei are not broken down. Only the carboxyl function is mineralised. Radiochromatography shows that through the action of the humic acids the tryptophan is broken down primarily into indoleacetamide and secondarily into β-indoleacetic acid. From the nature of these compounds it is assumed that the humic acids have an oxygenas effect on thel-tryptophan. The enzymatic activity has its optimum value at 65°C. It is partially inhibited by lyophilisation and by toluene. The pyridoxal phosphate (0.1 μM) has a slight activating influence. The alkalis and mineral acids decompose the enzyme. We can therefore see just how much importance attaches to the humic matter, not only as an energy substrate reserve for the micro-organisms and plants but also as a site for biological activities which are quite distinct from any microbial proliferation and the role of which in plants has still to be studied. It would be of interest to determine the presence of this enzymatic system in other pedologically defined soils and to study it in correlation with their fertility. In addition, there remains the task of detecting the microbial agents in the soil which contribute to the formation of this remarkable enzymatic system.  相似文献   

4.
The structure analysis and antigenicity study of the N protein of SARS-CoV   总被引:2,自引:0,他引:2  
The Coronaviridae family is characterized by a nucleocapsid that is composed of the genome RNA molecule in combination with the nucleoprotein (N protein) within a virion. The most striking physiochemical feature of the N protein of SARS-CoV is that it is a typical basic protein with a high predicted pI and high hydrophilicity, which is consistent with its function of binding to the ribophosphate backbone of the RNA molecule. The predicted high extent of phosphorylation of the N protein on multiple candidate phosphorylation sites demonstrates that it would be related to important functions, such as RNA-binding and localization to the nucleolus of host cells. Subsequent study shows that there is an SR-rich region in the N protein and this region might be involved in the protein-protein interaction. The abundant antigenic sites predicted in the N protein, as well as experimental evidence with synthesized polypeptides, indicate that the N protein is one of the major antigens of the SARS-CoV. Compared with o  相似文献   

5.
6.
During examination of spider material in the Institute of Zoology,Chinese Academy of Sciences (IZCAS),one male specimen came to our attention,which showed a unique anomaly in its palp.The morphology of this specimen is documented and suggestions for further investigations are given.Material. 2 males,Zhangjiajie National Park (29 08°N,110.29°E)[reared to adult,leg.LI Shu Qiang];deposited in the Institute of Zoology,Chinese Academy of Sciences,Beijing:Araneae,Sparassidae#89.One of the males has both palps intact and belongs to a Sinopoda species,which has yet to be determined.In the other specimen only the left palp is present in a deformed state.From size and color of both specimens,it could be possible that both are conspecific.Morphology. The anomalous morphology is limited to the palpal tarsus and to the retrolateral tibial apophysis (RTA).All remaining parts of the palp show a normal expression of morphological characters(e.g.spination,size,shape).The RTA is deformed in a way as recorded for e.g.Erigone atra (Jaeger, 1995),i.e.its size is reduced and its shape is different in comparison with the intact specimen.The main anomaly refers to the bulb,on the ventral side of the male tarsus.Usually,the bulb of sparassids composed of two sclerotized parts,tegulum and subtegulum,both separated by membranous parts,the haematodochae(cf.Yin et al.,1983).The basal haematodocha connects the subtegulum to the cymbium,the dorsal part of the tarsus.The cymbium bears hairs and contains nerves,whereas the bulb does not.In Sinopoda spp.embolus and conductor arise from the tegulum (Jaeger, 1999).A sperm duct extends from a distal opening on the embolus to the inner part of tegulum and subtegulum.  相似文献   

7.
正Sulfur is an essential nutrient for all organisms.It is present in amino acids cysteine and methionine,many co-enzymes and prosthetic groups,sulfolipids,sulfated peptides,and diverse secondary metabolites.Sulfur is taken up by plants as the inorganic oxidized anion sulfate,which is assimilated into the variety of cellular metabolites.Before sulfate can be assimilated,it must be activated by adenylation to adenosine 50-phosphosulfate(APS)by ATP sulfurylase(Fig.1).APS is a branching point of the assimilation:  相似文献   

8.
A green mutant was obtained among the chemically induced mutants of Rhodo-bacter sphaeroides 601 (RS601) and named GM309. A blue shift of 20 nm of the carotenoid absorption spectrum was found in the light-harvesting complex II (LH2) of GM309. Different from LH2 of RS601, it was found that the carotenoids in GM309-LH2 changed to be neurosporene by mutation. Neurosporene lacks a conjugate double bond, compared with the spheroidene in RS601-LH2 which has ten conjugate double bonds. As shown by absorption and circular di-chroism spectroscopy, the overall structure of GM309-LH2 is little affected by this change. From fluorescence emission spectra, it is found that GM309-LH2 can transfer energy from carotenoids to Bchl-B850 without any change in efficiency. But the efficiency of energy transfer from B800 to B850 in GM309-LH2 is decreased to be 42% of that of the native. This work would provide a novel method to investigate the mechanism of excitation energy transfer in LH2.  相似文献   

9.
Distinguishing things from beings, or matters from lives, is a fundamental question. Extending E. Schr?dinger's neg-entropy and I. Prigogine's dissipative structure, we propose a chemical kinetic view that the earliest "live" process is embedded essentially in a special interaction between a pair of specific components under a particular, corresponding environmental conditions. The interaction exists as an inter-molecular-force-bond complex(IMFBC) that couples two separate chemical processes: one is the spontaneous formation of the IMFBC driven by a decrease of Gibbs free energy as a dissipative process; while the other is the disassembly of the IMFBC driven thermodynamically by free energy input from the environment. The two chemical processes coupled by the IMFBC originated independently and were considered non-living on Earth, but the IMFBC coupling of the two can be considered as the earliest form of metabolism: the first landmark on the path from things to a being. The dynamic formation and disassembly of the IMFBC, as a composite individual, follows a principle designated as "… structure for energy for structure for energy…", the cycle continues; and for short it will be referred to as "structure for energy cycle". With additional features derived from this starting point, the IMFBC-centered "live" process spontaneously evolved into more complex living organisms with the characteristics currently known.  相似文献   

10.
Morphological Measurement and Analysis of Gymnarchus Niloticus   总被引:5,自引:0,他引:5  
Gymnarchus niloticus swims by undulations of a long-based dorsal fin, while its body axis is in many cases held straight during swimming. This paper provides a brief relevant introduction to Gymnarchus niloticus , which belongs to the African freshwater electric eels but can inspire our bionic interests in propulsion besides its abilities in electric sensing. A special larva of Gymnarchus niloticus was morphologically measured by photographing it with a piece of scale-calibrated paper as the background. Then we analyzed the data by a CFD-aided approach. Detailed flow patterns around the larva and a NACA0012 hydrofoil were respectively calculated and visualized at the Reynolds number of 7350 or so. The results show that the profile of Gymnarchus niloticus is well streamlined.  相似文献   

11.
Mammarenaviruses, including lethal pathogens such as Lassa virus and Junín virus, can cause severe hemorrhagic fever in humans. Entry is a key step for virus infection, which starts with binding of the envelope glycoprotein(GP) to receptors on target cells and subsequent fusion of the virus with target cell membranes. The GP precursor is synthesized as a polypeptide, and maturation occurs by two cleavage events, yielding a tripartite GP complex(GPC) formed by a stable signal peptide(SSP), GP1 and GP2. The unique retained SSP interacts with GP2 and plays essential roles in virion maturation and infectivity. GP1 is responsible for binding to the cell receptor, and GP2 is a class I fusion protein. The native structure of the tripartite GPC is unknown.GPC is critical for the receptor binding, membrane fusion and neutralization antibody recognition.Elucidating the molecular mechanisms underlining the structure–function relationship of the three subunits is the key for understanding their function and can facilitate novel avenues for combating virus infections. This review summarizes the basic aspects and recent research of the structure–function relationship of the three subunits. We discuss the structural basis of the receptor-binding domain in GP1, the interaction between SSP and GP2 and its role in virion maturation and membrane fusion, as well as the mechanism by which glycosylation stabilizes the GPC structure and facilitates immune evasion. Understanding the molecular mechanisms involved in these aspects will contribute to the development of novel vaccines and treatment strategies against mammarenaviruses infection.  相似文献   

12.
Nanohairs, which can be found on the epidermis of Tokay gecko's toes, contribute to the adhesion by means of van der Waals force, capillary force, etc. This structure has inspired many researchers to fabricate the attachable nano-scale structures. However, the efficiency of artificial nano-scale structures is not reliable sufficiently. Moreover, the mechanical parameters related to the nano-hair attachment are not yet revealed qualitatively. The mechanical parameters which have influence on the ability of adhesive nano-hairs were investigated through numerical simulation in which only van der Waals force was considered. For the numerical analysis, finite element method was utilized and van der Waals force, assumed as 12-6 Lennard-Jones potential, was implemented as the body force term in the finite element formulation.  相似文献   

13.
Net biome production (NBP) is considered as the most appropriate concept for analyz-ing long-term and large-scale changes of the carbon cycle induced by land use. We have esti-mated NBP potential of Japanese managed forests, based on their age structure, to be 16 Mt C/a. Fifty-nine percent of this sink is located in the warm-temperate broadleaf forest zone and the re-maining 39% is located in the cool-temperate broadleaf forest zone. This potential of NBP could be achieved under a long rotation period (70 a) and may serve as a target for sink enhancement ef-forts with the potential to uptake up to 4% of current fossil fuel emissions.  相似文献   

14.
Ebola virus(EBOV) causes severe hemorrhagic fever in humans and non-human primates with high rates of fatality. Glycoprotein(GP) is the only envelope protein of EBOV, which may play a critical role in virus attachment and entry as well as stimulating host protective immune responses.However, the lack of expression of full-length GP in Escherichia coli hinders the further study of its function in viral pathogenesis. In this study, the vp40 gene was fused to the full-length gp gene and cloned into a prokaryotic expression vector. We showed that the VP40-GP and GP-VP40 fusion proteins could be expressed in E.coli at 16 ℃. In addition, it was shown that the position of vp40 in the fusion proteins affected the yields of the fusion proteins, with a higher level of production of the fusion protein when vp40 was upstream of gp compared to when it was downstream. The results provide a strategy for the expression of a large quantity of EBOV full-length GP, which is of importance for further analyzing the relationship between the structure and function of GP and developing an antibody for the treatment of EBOV infection.  相似文献   

15.
16.
Yu Wen 《古生物学报》1988,(3):306-307
A strange fossil described and illustrated in the present paper was collected by the writer in 1978 from the Huangshandong Member of the Lower Cambrian Tongying Formation in western Hubei. The material was preserved in greyish brown phosphoritic dolomites in association with elements of the Yangtze Micromolluscan Fauna, such as Tchangsichiton notabilus Yu and Sinuconus clypeus, Yu of Class Polyplacophora; Yangtzemerisma rarum Yu and Y.? cancellatum Yu of Class Merismoconchia; Yangtzeconus priscus Yu, Huangshandongoconus pileus Yu, Obtusoconus paucicostatus Yu, O. rostriptutea (Qian) and Spatuloconus rudis Yu of Class Monoplacophora; Bemella simplex Yu, Latouchlla of. memmorabilis Missarzhevsky, L. sanxiaesis Yu and L. lauta Yu of Class uncertain; Archaeospira ornata Yu, A. imbricata Yu and Cambrospira sinensis Yu of Class Gastropoda; Heraultipegma yunnanense He et Yang of Class Rostroconcbia: hyolithids and some other uncertain skeletal fossils. Although the systematic position of this peculiar fossil is unknown at present, it is inferred that this genus may be one of the typical primitive animal groups based on the characters of the shell and the spe cial spines. The shell is bilaterally symmetrical, elliptical in apical view; the dorsal side is roundly convex with three different forms of dorsal spines and several pairs of marginal spines on the anterior margin. Judged from the general morphological characters of the bilaterally symmetrical shell, these lower animals, generally speaking, have adapted themselves readily to different circumstances, and reduced resistance to any directional movement necessary for varied physiological activities. As to the function of the shell’s characteristics, the narrowly rounded side may serve as the anterior. Such a model of the body helps these animals go on with their benthonic creeping or swimming life. On the other hand, the dorsal spines are different from each other in shape, size, mode of arrangement and in number; especially, the end of the hook-shaped spines is generally curved outward, while the geniculate spines are oblique outward, and curved posteriorly all of a sudden. These structures of mechanism also provide us with the evidence that the narrowly rounded side serves as the anterior, while the opposite end as the posterior.It is of particular interest that this genus is somewhat similar to Phylum Mollusca, especially to the tryblidiids of Class Monoplacophora, in some morphological characters, such as: 1) the bilateral symmetry of the shell, 2) the outline elliptical in apical view and cap shaped in lateral view and 3) the dorsal side generally roundly convex. After careful study, it has been found that since this genus is strikingly different from monoplacopharans, may be it belongs to another interesting group of skeletal fossils. The reasons for this are: 1) in the former, there are many pairs of marginal spines on the anterior margin, while in monoplacophorans, no marginal spines can be seen; and 2) in this genus, the sculptures are different from each other in different areas, not only in shape and number, but also in the mode of arrangement, whereas in monoplacophorans, they are identical with each other in the same type and shape. Judged from the different forms of dorsal sculptures, this genus is comparatively similar to such uncertain shelly fossils as Lepidites Zhong, 1977 emend. Yu, 1987 and Xiadongoconus Yu, 1979 from the same horizon in the Yangtze Region of China, but differs from the latter two genera in the presence of marginal spines on the anterior margin. In addition, this new genus also differs from brachiopods and other skeletal fossils in the peculiar type of the shell. According to the above comparison, this genus is entirely different from all the classes of Phylum Mollusca, possibly representing another interesting group of skeletal fossils. It is impossible to determine the exact taxonomic position of this genus until more materials are available.  相似文献   

17.
Du J  Cai SH  Shi Z  Nagase F 《Cell research》2004,14(2):148-154
H-Ras is well known as one of the essential components of Ras/Raf/MEK/ERK cascade, which is a critical prosurvival signaling mechanism in most eukaryotic cells. Ras targets Raf/MEK/ERK cascade by integrating and transmitting extracellular signals from growth factor receptors to Raf, leading to the propagation of signals to modulate a serious of cellular survival events. Apoptosis signal-regulating kinasel (ASK1) serves as a general mediator of cell death because it is responsive to a variety of death signals. In this study, we found that H-Ras interacted with ASK1 to cause the inhibition of both ASK1 activity and ASKl-induced apoptosis in vivo, which was reversed only partially by addition of RafS621 A, an antagonist of Raf, whereas MEK inhibitor, PD98059, and PI3K inhibitor, LY294002, did not disturb the inhibitory effect of H-Ras on ASK-1-induced apoptosis. Furthermore, by means of immunoprecipitate and kinase assays, we demonstrated that the interaction between H-Ras and ASK1 as well as the inhibition of ASKI activity were dependent on the binding activity of H-Ras. These results suggest that a novel mechanism may be involved in H-Rasmediated cell survival in addition to the well established MEK/ERK and PI3K/Akt kinase-dependent enhancement of cell survival.  相似文献   

18.
Biology has been a brilliant teacher and a precious textbook to man-made construction for thousands of years, because it allows one to learn and be inspired by nature's remarkable and efficient structural systems. However, the emerging biomimetic studies have been of increasing interest for civil engineering design only in the past two decades. Bridge design is one of aspects on structural engineering of biomimeties that offers an enormous potential for inspiration in various aspects, such as the ge- ometry, structure, mechanism, energy use and the intelligence. Recently built bridges and design proposals in which biological systems have produced a range of inspiration are reviewed in this paper. Multidisciplinary cooperation is discussed for the implementation of bio-inspired methods in future design. A case study about using bio-inspired strategy is trying to present a problem-solving approach, yet further cooperation is still needed to utilize biomimetie studies for design inspiration. This paper aims to call a close multidisciplinary collaboration that promotes engineers to build more sustainable and smart structural systems for bridges in the 21 st century.  相似文献   

19.
Exploring the mechanisms of maintaining microbial community structure is important to understand biofilm development or microbiota dysbiosis. In this paper, we propose a functional gene-based composition prediction(FCP) model to predict the population structure composition within a microbial community. The model predicts the community composition well in both a low-complexity community as acid mine drainage(AMD) microbiota, and a complex community as human gut microbiota. Furthermore, we define community structure shaping(CSS) genes as functional genes crucial for shaping the microbial community. We have identified CSS genes in AMD and human gut microbiota samples with FCP model and find that CSS genes change with the conditions. Compared to essential genes for microbes, CSS genes are significantly enriched in the genes involved in mobile genetic elements, cell motility, and defense mechanisms, indicating that the functions of CSS genes are focused on communication and strategies in response to the environment factors. We further find that it is the minority, rather than the majority, which contributes to maintaining community structure. Compared to health control samples, we find that some functional genes associated with metabolism of amino acids, nucleotides, and lipopolysaccharide are more likely to be CSS genes in the disease group. CSS genes may help us to understand critical cellular processes and be useful in seeking addable gene circuitries to maintain artificial self-sustainable communities. Our study suggests that functional genes are important to the assembly of microbial communities.  相似文献   

20.
BLCAP is a potential gene for suppression of cervical carcinoma, which was found by analysing the cervical carcinoma specimen with the oncogene and anti-oncogene cDNA microarray. Basing on the bioinformatical analyses, we try to predict the function of blcap gene. The results show that there are several genes that highly resemble with blcap. The comparability between the sequences of blcap and Homo sapiens mRNA (DKFZp564M053) or BC10 is 99% and 87%, respectively. The protein encoded by BLCAP is composed of Leu(19.5%), pro(9.19%), ser(8.04%)、 cys(8.04%) and other amino acids. The secondary structure of the N-terminal of BLCAP encoded protein is an alpha helix. In the C-terminal, it is beta sheet and in the middle, it is coil. The of the terminals is more hydrophobile than the middle region. Between 45-55aa, there is a transmembrane region. Therefore, we forecast the BLCAP is a member of transmembrane protein I. By analyzing the signal peptide and the procedure of blcap gene with the program of SignalP (V1.1), we found a cleavage site in 59-66aa. By using the program of Netpho, we predicted there might be three phospholate sites at 68aa, 73aa and 78aa. At 78-81aa, we found a typical [ST]-X [2] -[DE] structure—the phospholate site of tyrosine protein kinase, which might be related to its function. Bioinformatic studies of blcap provided the foundation for the function researches of BLCAP in laboratory.  相似文献   

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