共查询到20条相似文献,搜索用时 187 毫秒
1.
P. Fusi M. Villa N. Burlini P. Tortora A. Guerritore 《Cellular and molecular life sciences : CMLS》1991,47(10):1057-1060
Proteolytic activities from the extremely thermoacidophilic archaebacteriumSulfolobus solfataricus were detected with the aid of synthetic substrates in a cell extract fractionated by gel filtration. Two aminopeptidases (aminopeptidase I and II), three endopeptidases (proteinase I, II and III) and one carboxypeptidase could be identified. Experiments carried out with protease inhibitors led to the identification of the exopeptidases as metalloproteases. Proteinases I and II behaved as chymotrypsin-like serine proteases, and proteinase III as a cysteine protease with a trypsin-like specificity. Molecular weight values assessed with the aid of marker proteins were as follows: aminopeptidase I, >450 kDa; aminopeptidase II, 170 kDa; carboxypeptidase, 160 kDa; proteinase I, 115 kDa; proteinase II, 32 kDa; proteinase III, 27 kDa. On incubation for 15 min they retained most of their activity up to a temperature of 90°C, with the sole exception of proteinase II, which was rapidly inactivated at 60°C. Protease content was also determined in crude extracts from cells grown in a mineral medium both to the stationary and to the exponential phase, with glucose or with yeast extract as carbon sources. No dramatic change was detected depending on the growth phase; however, carboxypeptidase level was three- to four-fold higher when yeast extract was present in the medium instead of glucose; this might suggest an involvement of this enzyme in the digestion of extracellularly available peptides. 相似文献
2.
A. Di Pasquale Paladino P. Cavolina G. Romano R. Ribaudo 《Cellular and molecular life sciences : CMLS》1988,44(9):777-779
Summary 3rd instar larvae of the melanotic tumortu-pb strain ofDrosophila melanogaster hold a lower number of free-circulating crystal cells in their hemolymph than the wild type ones. This pattern could result from an abnormal retention of mature crystal cells in the hematopoietic organs, as the strong hemocyte melanization inside the lymph glands of heat-treatedtu-pb larvae seems to demonstrate. Melanotic tumor formation and modification of the crystal cell pattern may be related. 相似文献
3.
4.
M. Samish 《Cellular and molecular life sciences : CMLS》1990,46(2):224-225
Information concerning the specific nutritional requirements of malarial parasites developing in the mosquito host has been difficult to obtain, owing primarily to the complex nature of the blood meal that accompanies the parasites and the lack of success in culturing the complete invertebrate cycle ofPlasmodium in vitro. The present report describes a blood-free system for infecting mosquitoes with ookinetes ofPlasmodium berghei and for allowing the latter to develop into infective sporozoites. Ookinetes cultured in vitro were separated from blood proteins, suspended in defined medium, and fed toAnopheles stephensi mosquitoes through a membrane. The mosquitoes were then maintained on the same defined medium plus 5% sucrose. Infectivity of the parasites was demonstrated 17–19 days later by intracardial inoculation of the macerated mosquitoes into hamsters. This system makes it possible to evaluate nutritional factors that affect parasite development in the mosquito host under controlled conditions.This project was supported, in part, by the Public Health Service research grant AI-18345 from the National Institute of Allergy and Infectious Diseases to Prof. K. Maramorosch, and the Charles and Johanna Busch Memorial Fund at Rutgers, The State University of New Jersey. 相似文献
5.
2-Phenylethanol,a presumed sexual stimulant produced by the male cabbage looper moth,Trichoplusia ni
M. Jacobson V. E. Adler A. N. Kishaba E. Priesner 《Cellular and molecular life sciences : CMLS》1976,32(8):964-966
Summary A sex pheromone produced by male cabbage looper moths,Trichoplusia ni (Hübner), has been isolated from the genital scent brushes and identified as 2-phenylethanol. It is shown conclusively to elicit specific behavioural responses in the female (such as wing vibration and abdominal elevation), as determined by a novel behavioural laboratory bioassay. This is taken as further evidence that the male pheromone ofT. ni acts as a sexual stimulant (aphrodisiac) prior to mating. 2-Phenylethanol represents the first identification of a genital scent brush pheromone in the family Noctuidae, and of a male pheromone in the subfamily Plusiinae.Mention of a proprietary product in this paper does not constitute a recommendation or an endorsement of the product by the U. S. Department of Agriculture. 相似文献
6.
Highly active metabolites have been detected in the hemolymph of the lepidopteranSpodoptera exigua infected with the mycopathogen,Beauveria bassiana. A combination of phenyl sepharose and CM ion exchange chromatography was utilized to extract the active metabolites from infected hemolymph samples. The active in vivo metabolites, having a molecular mass greater than 10 KDa, were thermolabile and were inactivated by proteinase K. These metabolites were characterized by their ability to disrupt metamorphosis, killing treated larvae at the wandering or pupal stage. Additionally, injection ofS. exigua larvae with active samples caused a reduction in the number of filopodial-producing hemocytes. The biological activities and biochemical properties suggest that novel compounds are produced duringB. bassiana mycosis. 相似文献
7.
A. B. Jones G. Fakhouri P. Gadiel 《Cellular and molecular life sciences : CMLS》1979,35(11):1432-1434
Summary The soil fumigant 1,2-dibromo-3-chloropropane (I) undergoes hydrolysis in the rat to a series of epoxide metabolites. Alkylation of glutathione by these epoxides produces 2 urinary metabolites identified as the mercapturic acids VI (R=COCH3) and VII (R=COCH3). Hydrolysis of the epoxides produces the male antifertility agentsa-chlorohydrin (IX, X=Cl) anda-bromohydrin (IX, X=Br) which are oxidatively metabolized to oxalic acid (XII), thus causing renal damage. These metabolic pathways can explain the toxic nature of the fumigant as a carcinogen, a male chemosterilant and as an agent causing kidney damage.This work was supported in part by the National Health and Medical Research Council of Australia. 相似文献
8.
Summary Injections of male accessory gland material fromAedes aegypti into the hemocoeles of virgin female mosquitoes indicate that the potency of the secretion is equivalent to the amount of semen which a male normally places within the female. This estimation is far less than had been previously calculated. It is suggested that the termmatrone for male accessory gland material is inappropriate since it does not convert a maid into a matron but prevents reinsemination of an impregnated female.Scientific Article No. A2098, Contribution No. 5054 of the Maryland Agricultural Experiment Station. 相似文献
9.
O. Kuhn E. Kubli E. Hauschteck-Jungen 《Cellular and molecular life sciences : CMLS》1972,28(8):982-983
Summary In the brain of the honeybee (Apis mellifica), it was found that the rRNA content decreases rapidly during the first 2 days of adult life. An increase is observed from days 3 to 5, followed by another decrease to a level inferior to that of day 2 to 3. Except for a rise on the 5th day, 4s RNA remains constant. An unidentified RNA fraction of low molecular weight (D) sharply decreases on day 5. The possibility is discussed that these results reflect changes in RNA metabolism that can be related to the sequences of activity observed in the bees during the first 9 days after hatching. 相似文献
10.
Panizzi P Friedrich R Fuentes-Prior P Bode W Bock PE 《Cellular and molecular life sciences : CMLS》2004,61(22):2793-2798
Staphylocoagulase (SC) secreted by Staphylococcus aureus is a potent non-proteolytic activator of the blood coagulation zymogen prothrombin and the prototype of a newly established
zymogen
activator and
adhesion
protein (ZAAP) family. The conformationally activated SC·prothrombin complex specifically cleaves fibrinogen to fibrin, which propagates the growth of bacteria-fibrin-platelet vegetations in acute bacterial endocarditis. Our recent 2.2 Å X-ray crystal structures of an active SC fragment [SC(1-325)] bound to the prothrombin zymogen catalytic domain, prethrombin 2, demonstrated that SC(1-325) represents a new type of non-proteolytic activator with a unique fold. The observed insertion of the SC(1-325) N-terminus into the Ile 16 cleft of prethrombin 2, which triggers the activating conformational change, provided the first unambiguous structural evidence for the molecular sexuality mechanism of non-proteolytic zymogen activation. Based on the SC(1-325) fold, a new family of bifunctional zymogen activator and adhesion proteins was identified that possess N-terminal domains homologous to SC(1-325) and C-terminal domains that mediate adhesion to plasma or extracellular matrix proteins. Further investigation of the ZAAP family may lead to new insights into the mechanisms of bacterial factors that hijack zymogens of the human blood coagulation and fibrinolytic systems to promote and disseminate endocarditis and other infectious diseases.Received 30 June 2004; received after revision 28 July 2004; accepted 4 August 2004 相似文献
11.
S. Tahara S. Kasai M. Inoue J. Kawabata J. Mizutani 《Cellular and molecular life sciences : CMLS》1994,50(2):137-141
In a survey of antifungal stress compounds induced by cupric chloride we found that leaves ofChenopodium album exuded a highly fungitoxic metabolite mucondialdehyde (trans-2,trans-4-hexadienedial), which was associated with 13-oxo-9,11-tridecadienoic acids (cis-9,trans-11 andtrans-9,trans-11 isomers) presumably resulting from -scission of 13-hydroperoxy-octadecadi(tri)enoic acid. The biogenesis and role as a general defensive agent in plants are briefly discussed. 相似文献
12.
Myocardial infarction might result from the interactions of multiple genetic and environmental factors, none of which can cause disease solely by each of themselves. Although molecular biological studies revealed that a number of proteins are possibly involved in its pathogenesis, little, if any genetic findings have been reported so far. To reveal genetic backgrounds of myocardial infarction, we performed a large-scale, case-control association study using 92,788 gene-based single-nucleotide polymorphism (SNP) markers. We have identified functional SNPs within the lymphotoxin-α gene (LTA) located on chromosome 6p21 that conferred susceptibility to myocardial infarction. Furthermore, we could identify galectin-2 protein as a binding partner of LTA protein. The association study further revealed that a functional SNP in LGALS2 encoding galectin-2, which led to altered secretion of LTA, also indicated a risk of myocardial infarction. A combined strategy of genetic and molecularcellular biological approaches may be useful in clarifying pathogenesis of common diseases.Received 7 March 2005; received after revision 22 April 2005; accepted 25 April 2005 相似文献
13.
Mikko Hellgren Jonas Carlsson Linus J. Östberg Claudia A. Staab Bengt Persson Jan-Olov Höög 《Cellular and molecular life sciences : CMLS》2010,67(17):3005-3015
Alcohol dehydrogenase 3 (ADH3) has been assigned a role in nitric oxide homeostasis due to its function as an S-nitrosoglutathione reductase. As altered S-nitrosoglutathione levels are often associated with disease, compounds that modulate ADH3 activity might be of therapeutic
interest. We performed a virtual screening with molecular dockings of more than 40,000 compounds into the active site of human
ADH3. A novel knowledge-based scoring method was used to rank compounds, and several compounds that were not known to interact
with ADH3 were tested in vitro. Two of these showed substrate activity (9-decen-1-ol and dodecyltetraglycol), where calculated
binding scoring energies correlated well with the logarithm of the k
cat/K
m values for the substrates. Two compounds showed inhibition capacity (deoxycholic acid and doxorubicin), and with these data
three different lines for specific inhibitors for ADH3 are suggested: fatty acids, glutathione analogs, and cholic acids. 相似文献
14.
Sarno S Mazzorana M Traynor R Ruzzene M Cozza G Pagano MA Meggio F Zagotto G Battistutta R Pinna LA 《Cellular and molecular life sciences : CMLS》2012,69(3):449-460
8-hydroxy-4-methyl-9-nitrobenzo(g)chromen-2-one (NBC) has been found to be a fairly potent ATP site-directed inhibitor of
protein kinase CK2 (Ki = 0.22 μM). Here, we show that NBC also inhibits PIM kinases, especially PIM1 and PIM3, the latter
as potently as CK2. Upon removal of the nitro group, to give 8-hydroxy-4-methyl-benzo(g)chromen-2-one (here referred to as
“denitro NBC”, dNBC), the inhibitory power toward CK2 is almost entirely lost (IC50 > 30 μM) whereas that toward PIM1 and PIM3 is maintained; in addition, dNBC is a potent inhibitor of a number of other kinases
that are weakly inhibited or unaffected by NBC, with special reference to DYRK1A whose IC50 values with NBC and dNBC are 15 and 0.60 μM, respectively. Therefore, the observation that NBC, unlike dNBC, is a potent
inducer of apoptosis is consistent with the notion that this effect is mediated by inhibition of endogenous CK2. The structural
features underlying NBC selectivity have been revealed by inspecting its 3D structure in complex with the catalytic subunit
of Z. mays CK2. The crucial role of the nitro group is exerted both through a direct electrostatic interaction with the side chain of Lys68
and, indirectly, by enhancing the acidic dissociation constant of the adjacent hydroxyl group which interacts with a conserved
water molecule in the deepest part of the cavity. By contrast, the very same nitro group is deleterious for the binding to
the active site of DYRK1A, as disclosed by molecular docking. This provides the rationale for preferential inhibition of DYRK1A
by dNBC. 相似文献
15.
Tsitsanou KE Thireou T Drakou CE Koussis K Keramioti MV Leonidas DD Eliopoulos E Iatrou K Zographos SE 《Cellular and molecular life sciences : CMLS》2012,69(2):283-297
Insect odorant binding proteins (OBPs) are the first components of the olfactory system to encounter and bind attractant and
repellent odors emanating from various sources for presentation to olfactory receptors, which trigger relevant signal transduction
cascades culminating in specific physiological and behavioral responses. For disease vectors, particularly hematophagous mosquitoes,
repellents represent important defenses against parasitic diseases because they effect a reduction in the rate of contact
between the vectors and humans. OBPs are targets for structure-based rational approaches for the discovery of new repellent
or other olfaction inhibitory compounds with desirable features. Thus, a study was conducted to characterize the high resolution
crystal structure of an OBP of Anopheles gambiae, the African malaria mosquito vector, in complex with N,N-diethyl-m-toluamide (DEET), one of the most effective repellents that has been in worldwide use for six decades. We found that DEET
binds at the edge of a long hydrophobic tunnel by exploiting numerous non-polar interactions and one hydrogen bond, which
is perceived to be critical for DEET’s recognition. Based on the experimentally determined affinity of AgamOBP1 for DEET (K
d of 31.3 μΜ) and our structural data, we modeled the interactions for this protein with 29 promising leads reported in the
literature to have significant repellent activities, and carried out fluorescence binding studies with four highly ranked
ligands. Our experimental results confirmed the modeling predictions indicating that structure-based modeling could facilitate
the design of novel repellents with enhanced binding affinity and selectivity. 相似文献
16.
Nile CJ Townes CL Michailidis G Hirst BH Hall J 《Cellular and molecular life sciences : CMLS》2004,61(21):2760-2766
Lysozyme is an important component of the innate immune system, protecting the gastrointestinal tract from infection. The aim of the present study was to determine if lysozyme is expressed in the chicken (Gallus gallus) intestine and to characterise the molecular forms expressed. Immunohistochemical staining localised lysozyme to epithelial cells of the villous epithelium along the length of the small intestine. There was no evidence for lysozyme expression in crypt epithelium and no evidence for Paneth cells. Immunoblots of chicken intestinal protein revealed three proteins: a 14-kDa band consistent with lysozyme c, and two additional bands of approximately 21 and 23 kDa, the latter consistent with lysozyme g. RT-PCR analyses confirmed that lysozyme c mRNA is expressed in 4-day, but not older chicken intestine and lysozyme g in 4- to 35-day chicken intestine. A novel chicken lysozyme g2 gene was identified by in silico analyses and mRNA for this lysozyme g2 was identified in the intestine from chickens of all ages. Chicken lysozyme g2 shows similarity with fish lysozyme g, including the absence of a signal peptide and cysteines involved in disulphide bond formation of the mammalian and bird lysozyme g proteins. Analyses using SecretomeP predict that chicken lysozyme g2 may be secreted by the non-classical secretory pathway. We conclude that lysozyme is expressed in the chicken small intestine by villous enterocytes. Lysozyme c, lysozyme g and g2 may fulfil complimentary roles in protecting the intestine.Received 4 August 2004; received after revision 1 September 2004; accepted 7 September 2004 相似文献
17.
F. Weygand A. Wacker V. Schmied-Kowarzik 《Cellular and molecular life sciences : CMLS》1948,4(11):427-428
Summary By condensing 2:4:5-triamino-6-hydroxy-pyrimidine with dihydroxyacetone (diacetate), diaminoacetone or acetone-1,3-di (p-formylaminobenzoic acid) not the expected 8- or 9-oxymethyl resp. -aminomethyl-pteridines but 8-or 9-methyl-pteridines were obtained. With p-tolyl-d-isoglucosamine not a tetrahydroxybutyl-pteridine but a trihydroxybutyl-pteridine was formed. For an explanation of these results it is supposed that from the dihydro-pteridines formed at first by intramolecular splitting off of H2O or R·NH2 aromatization takes place. 相似文献
18.
Jacquet S Malaval C Martinez LO Sak K Rolland C Perez C Nauze M Champagne E Tercé F Gachet C Perret B Collet X Boeynaems JM Barbaras R 《Cellular and molecular life sciences : CMLS》2005,62(21):2508-2515
Cell surface receptors for high-density lipoprotein (HDL) on hepatocytes are major partners in the regulation of cholesterol
homeostasis. We recently identified a cell surface ATP synthase as a high-affinity receptor for HDL apolipoprotein A-I (apoA-I)
on human hepatocytes. Stimulation of this ectopic ATP synthase by apoA-I triggered a low-affinity-receptor-dependent HDL endocytosis
by a mechanism strictly related to the generation of ADP. This suggests that nucleotide G-protein- coupled receptors of the
P2Y family are molecular components in this pathway. Only P2Y1 and P2Y13 are present on the membrane of hepatocytes. Using both a pharmacological approach and small interference RNA, we identified
P2Y13 as the main partner in hepatic HDL endocytosis, in cultured cells as well as in situ in perfused mouse livers. We also found
a new important action of the antithrombotic agent AR-C69931MX as a strong activator of P2Y13-mediated HDL endocytosis.
Received 9 May 2005; received after revision 24 June 2005; accepted 1 September 2005 相似文献
19.
Tibaldi E Arrigoni G Brunati AM James P Pinna LA 《Cellular and molecular life sciences : CMLS》2006,63(3):378-389
In an attempt to gain information about the identity of the Golgi apparatus casein kinase(s) (G-CK), responsible for the phosphorylation
of caseins in lactating mammary gland, the proteins present in fractions enriched in G-CK activity eluted from DEAE-Sepharose
and heparin-Sepharose columns were resolved by two-dimensional electrophoresis and analyzed by mass spectrometry. This led
to the identification of 47 proteins altogether, none of which is a bona fide protein kinase. At least 9 of the identified
proteins however, are readily phosphorylated by co-purifying G-CK activity, and 7 are physically associated with it to give
supramolecular complex(es) of about 500 kDa as judged from Superdex S200 gel fitration and glycerol gradient ultracentrifugation
experiments. In contrast, the apparent molecular weight of G-CK estimated from an in gel activity assay after SDSPAGE and
renaturation is about 41 kDa. Many of the proteins phosphorylated by and/or associated with G-CK belong to the category of
chaperonines, including HSP90, GRP-94 and −78, and various isoforms of protein disulfide isomerases, suggesting a global role
of this kinase in the modulation of protein folding.
Received 21 October 2005; received after revision 30 November 2005; accepted 6 December 2005
†These authors contributed equally to this work. 相似文献
20.
Hellgren M Strömberg P Gallego O Martras S Farrés J Persson B Parés X Höög JO 《Cellular and molecular life sciences : CMLS》2007,64(4):498-505
The metabolism of all-trans- and 9-cis-retinol/ retinaldehyde has been investigated with focus on the activities of human, mouse and rat alcohol dehydrogenase 2
(ADH2), an intriguing enzyme with apparently different functions in human and rodents. Kinetic constants were determined with
an HPLC method and a structural approach was implemented by in silico substrate dockings. For human ADH2, the determined Km values ranged from 0.05 to 0.3 μM and kcat values from 2.3 to 17.6 min−1, while the catalytic efficiency for 9-cis-retinol showed the highest value for any substrate. In contrast, poor activities
were detected for the rodent enzymes. A mouse ADH2 mutant (ADH2Pro47His) was studied that resembles the human ADH2 setup.
This mutation increased the retinoid activity up to 100-fold. The Km values of human ADH2 are the lowest among all known human retinol dehydrogenases, which clearly support a role in hepatic
retinol oxidation at physiological concentrations.
Received 12 October 2006; received after revision 6 December 2006; accepted 8 January 2007 相似文献