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1.
A Caribbean cyanobacterium, Hormothamnion enteromorphoides, was found to produce a complex mixture of ichthyotoxic peptides, perhaps explaining the apparent absence of predation upon these potentially palatable life forms. Bioassay-guided fractionation was used to isolate these toxic and antimicrobial natural products, and a variety of techniques including HR FAB mass spectrometry, 2D-NMR, traditional hydrolysis-amino acid analysis, and several chemical reactions were used to define the basic structural features of the major peptide, hormothamnin A. Hormothamnin A is a cyclic undecapeptide containing six common and five uncommon or new amino acid residues. HPLC analyses indicate that the relative proportions of these peptide natural products remain relatively constant between different collection locations and years, however, they do vary seasonally. Clonal isolates of this cyanobacterium in culture produce the full spectrum of toxic peptides. 相似文献
2.
D. Brewer A. W. Hanson I. M. Shaw A. Taylor G. A. Jones 《Cellular and molecular life sciences : CMLS》1979,35(3):294-295
Summary Isolates ofTrichoderma spp. from pasture soils of Nova Scotia produce at least 7 toxic peptides, probably related to alamethicin, some of which inhibit the growth of cellulase producing rumen bacteria. One of the peptides has been obtained in crystalline form and crystal data on this material is reported. 相似文献
3.
Two classes of metabolites fromTheonella swinhoei are localized in distinct populations of bacterial symbionts 总被引:7,自引:0,他引:7
C. A. Bewley N. D. Holland D. J. Faulkner 《Cellular and molecular life sciences : CMLS》1996,52(7):716-722
The marine spongeTheonella swinhoei (lithistid Family Theonellidae, Order Astrophorida) has yielded many important, bioactive natural products, most of which share structural features with bacterial natural products. The presence of microbial symbionts inT. swinhoei has been reported, and it was originally suggested that the cytotoxic macrolide swinholide A and many of the bioactive cyclic peptides fromT. swinhoei were all produced by symbiotic cyanobacteria. By transmission electron microscopy, we found four distinct cell populations to be consistently present inT. swinhoei: eukaryotic sponge cells, unicellular heterotrophic bacteria, unicellular cyanobacteria and filamentous heterotrophic bacteria. Purification and chemical analyses of each cell type showed the macrolide swinholide A to be limited to the mixed population of unicellular heterotrophic bacteria, and an anti-fungal cyclic peptide occurred only in the filamentous heterotrophic bacteria. Contrary to prior speculation, no major metabolites were located in the cyanobacteria or sponge cells. 相似文献
4.
The venoms of predatory cone snails (genus Conus) have yielded a complex library of about 50–100,000 bioactive peptides, each believed to have a specific physiological target
(although peptides from different species may overlap in their target specificity). Conus has evolved the equivalent of a drug development strategy that combines the accelerated evolution of toxin sequences with
an unprecedented degree of posttranslational modification. Some Conus venom peptide families are the most highly posttranslationally modified classes of gene products known. We review the variety
and complexity of posttranslational modifications documented in Conus peptides so far, and explore the potential of Conus venom peptides as a model system for a more general understanding of which secreted gene products may have modified amino
acids. Although the database of modified conotoxins is growing rapidly, there are far more questions raised than answers provided
about possible mechanisms and functions of posttranslational modifications in Conus.
Received 24 June 2005; received after revision 13 August 2005; accepted 19 September 2005 相似文献
5.
Molecular characterization and expression of the antimicrobial peptide defensin from the housefly (Musca domestica) 总被引:2,自引:0,他引:2
Wang JX Zhao XF Liang YL Li L Zhang W Ren Q Wang LC Wang LY 《Cellular and molecular life sciences : CMLS》2006,63(24):3072-3082
A 430-bp cDNA encoding the insect antimicrobial peptide defensin was cloned from the housefly, and designated Musca domestica defensin (Mdde). The open reading frame of the cDNA encoded a 92-amino acid peptide with an N-terminal signal sequence followed by a propeptide
that is processed by cleavage to a 40-amino acid mature peptide. Northern analysis and in situ hybridization identified the corresponding mRNA in the fat body of bacterially challenged houseflies and in the epidermis
of the body wall of naive and challenged houseflies. The Gram-negative bacterium (Escherichia coli) is a strong inducer of the gene. By RT-PCR, Mdde mRNA was also detected in naive and challenged insects. These findings suggest that the defensin gene is constitutively expressed
in the epidermis of the housefly body wall. The predicted mature form of Mdde was expressed as a recombinant peptide in E. coli and Pichia pastoris. The recombinant Mdde expressed in Pichia was active against Gram-positive and some Gram-negative bacteria.
Received 20 June 2006; received after revision 3 October 2006; accepted 30 October 2006 相似文献
6.
Tommy Baumann Urs Kämpfer Stefan Schürch Johann Schaller Carlo Largiadèr Wolfgang Nentwig Lucia Kuhn-Nentwig 《Cellular and molecular life sciences : CMLS》2010,67(16):2787-2798
Three novel glycine-rich peptides, named ctenidin 1–3, with activity against the Gram-negative bacterium E. coli, were isolated and characterized from hemocytes of the spider Cupiennius salei. Ctenidins have a high glycine content (>70%), similarly to other glycine-rich peptides, the acanthoscurrins, from another spider, Acanthoscurria gomesiana. A combination of mass spectrometry, Edman degradation, and cDNA cloning revealed the presence of three isoforms of ctenidin, at least two of them originating from simple, intronless genes. The full-length sequences of the ctenidins consist of a 19 amino acid residues signal peptide followed by the mature peptides of 109, 119, or 120 amino acid residues. The mature peptides are post-translationally modified by the cleavage of one or two C-terminal cationic amino acid residue(s) and amidation of the newly created mature C-terminus. Tissue expression analysis revealed that ctenidins are constitutively expressed in hemocytes and to a small extent also in the subesophageal nerve mass. 相似文献
7.
E. Ottaviani A. Franchini P. Fontanili 《Cellular and molecular life sciences : CMLS》1994,50(9):857-859
The effect of corticotropin-releasing factor (CRF) and pro-opiomelanocortin (POMC)-derived peptides on hemocyte phagocytosis in two molluscs,Planorbarius corneus andViviparus ater was studied. The peptides and related fragments examined are those which have been shown to influence hemocyte motility in the two species. The results obtained revealed that the effects on phagocytosis are not directly correlated with previous findings on cell motility. Furthermore, the mode of action of an individual peptide could be species-specific and dose-dependent. The relationships between peptides, locomotion and phagocytosis in these molluscs are discussed. 相似文献
8.
Toniolo C Crisma M Formaggio F Peggion C Epand RF Epand RM 《Cellular and molecular life sciences : CMLS》2001,58(9):1179-1188
Lipopeptaibols are members of a novel group of naturally occurring, short peptides with antimicrobial activity, characterized
by a lipophilic acyl chain at the N-terminus, a high content of the turn/helix forming α-aminoisobutyric acid and a 1,2-amino alcohol at the C-terminus. The amino acid sequences range from 6 to 10 residues and
the fatty acyl moieties from 8 to 15 carbon atoms. The peptide portion of lipopeptaibols can be shorter than those of the
nonlipidated peptaibols that range from 10 to 19 amino acid residues. The longest peptides fold into a mixed 310/α helix, whereas the shortest peptides tend to adopt a β-turn/sheet structure. Using solution methodologies, a series of analogues of trichogin GA IV was synthesized which allowed
determination of the minimal lipid chain and peptide main-chain lengths for the onset of membrane activity and exploitation
of a number of spectroscopic techniques aimed at determining its preferred conformation under a variety of conditions and
investigating in detail its mode of interaction with, and its effect on, the phospholipid membranes.
Received 26 January 2001; received after revision 7 March 2001; accepted 15 March 2001 相似文献
9.
P. Gans V. Rossi C. Gaboriaud I. Bally J.-F. Hernandez M. J. Blackledge G. J. Arlaud 《Cellular and molecular life sciences : CMLS》1998,54(2):171-178
Synthetic peptides derived from the C-terminal end of the human complement serine protease C1s were analysed by circular
dichroism and nuclear magnetic resonance (NMR) spectroscopy. Circular dichroism indicates that peptides 656-673 and 653-673
are essentially unstructured in water and undergo a coil-to-helix transition in the presence of increasing concentrations
of trifluoroethanol. Two-dimensional NMR analyses performed in water/trifluoroethanol solutions provide evidence for the occurrence
of a regular α-helix extending from Trp659 to Ser668 (peptide 656-673), and from Tyr656 to Ser668 (peptide 653-673), the C-terminal segment
of both peptides remaining unstructured under the conditions used. Based on these and other observations, we propose that
the serine protease domain of C1s ends in a 13-residue α-helix (656Tyr-Ser668) followed by a five-residue C-terminal extension. The latter appears to be flexible and is probably
locked within C1s through a salt bridge involving Glu672.
Received 19 November 1997; accepted 24 November 1997 相似文献
10.
J. Schaller U. Kämpfer S. Schürch L. Kuhn-Nentwig S. Haeberli W. Nentwig 《Cellular and molecular life sciences : CMLS》2001,58(10):1538-1545
CSTX-9 (68 residues, 7530.9 Da) is one of the most abundant toxic polypeptides in the venom of the wandering spider Cupiennius salei. The amino acid sequence was determined by Edman degradation using reduced and alkylated CSTX-9 and peptides generated by
cleavages with endoproteinase Asp-N and trypsin, respectively. Sequence comparison with CSTX-1, the most abundant and the
most toxic polypeptide in the crude spider venom, revealed a high degree of similarity (53% identity). By means of limited
proteolysis with immobilised trypsin and RP-HPLC, the cystine-containing peptides of CSTX-9 were isolated and the disulphide
bridges were assigned by amino acid analysis, Edman degradation and nanospray tandem mass spectrometry. The four disulphide
bonds present in CSTX-9 are arranged in the following pattern: 1-4, 2-5, 3-8 and 6-7 (Cys6-Cys21, Cys13-Cys30, Cys20-Cys48, Cys32-Cys46). Sequence comparison of CSTX-1 with CSTX-9 clearly indicates the same disulphide bridge pattern, which is also found in
other spider polypeptide toxins, e.g. agatoxins (ω-AGA-IVA, ω-AGA-IVB, μ-AGA-I and μ-AGA-VI) from Agelenopsis aperta, SNX-325 from Segestria florentina and curtatoxins (CT-I, CT-II and CT-III) from Hololena curta. CSTX-1/CSTX-9 belong to the family of ion channel toxins containing the inhibitor cystine knot structural motif. CSTX-9,
lacking the lysine-rich C-terminal tail of CSTX-1, exhibits a ninefold lower toxicity to Drosophila melanogaster than CSTX-1. This is in accordance with previous observations of CSTX-2a and CSTX-2b, two truncated forms of CSTX-1 which,
like CSTX-9, also lack the C-terminal lysine-rich tail.
Received 23 July 2001; accepted 31 July 2001 相似文献
11.
G. E. Callander R. A. D. Bathgate 《Cellular and molecular life sciences : CMLS》2010,67(14):2327-2341
Since its discovery in the 1920s, relaxin has enjoyed a reputation as a peptide hormone of pregnancy. However, relaxin and
other relaxin family peptides are now associated with numerous non-reproductive physiologies and disease states. The new millennium
bought with it the sequence of the human genome and subsequently new directions for relaxin research. In 2002, the ancestral
relaxin gene RLN3 was identified from genome databases. The relaxin-3 peptide is highly expressed in a small region of the brain and in species
from teleost to primates and has both conserved sequence and sites of expression. Combined with the discovery of the relaxin
family peptide receptors, interest in the role of the relaxin family peptides in the central nervous system has been reignited.
This review explores the relaxin family peptides that are expressed in or act upon the brain, the receptors that mediate their
actions, and what is currently known of their functions. 相似文献
12.
Toxicity quantification is important in environmental monitoring, in the field of natural products, and in chemical ecology. The sensitivity and precision of three commonly used methods detecting toxicity in marine environments were compared, using the toxic marine spongeCrambe crambe as a test organism. The paper disk diffusion method (run with marine bacteria) showed the least sensitivity and did not permit toxicity levels to be quantified. The sea urchin and the MICROTOX® tests showed greater sensitivity, and the latter had the higher precision. The relative performance of these methods is discussed. It is concluded that the MICROTOX® bioassay displays the best characteristics for toxicity quantification. 相似文献
13.
Chemical defence in the larvae of the leaf beetleGonioctena viminalis L. (Coleoptera: Chrysomelidae)
Summary The leaf beetle larva ofGonioctena (Phytodecta) viminalis L. has been shown to produce five volatile constituents within its paired abdominal defensive gland reservoirs. It is the first time that these compounds have been reported to occur in coleopteran defensive glands (linalool, phenylethanol) and Chrysomelidae larvae (6-methyl-5-hepten-2-one, 6-methyl-5-hepten-2-ol, 2-hexenal). In addition to the gross morphology of theGonioctena gland and its discharge behavior, the natural products found are discussed in terms of chemotaxonomy. 相似文献
14.
Mukhopadhyay A Ni L Yang CS Weiner H 《Cellular and molecular life sciences : CMLS》2005,62(16):1890-1899
Phage display was used to identify new components of the mammalian mitochondrial receptor complex using Tom20 as a binding partner. Two peptides were identified. One had partial identity (SMLTVMA) with a bacterial signal peptide from Toho-1, a periplasmic protein. The other had partial identity with a mitochondrial inner membrane glutamate carrier. The bacterial signal peptide could carry a protein into mitochondria both in vivo and in vitro. The first six residues of the sequence, SMLTVM, were necessary for import but the two adjacent arginine residues in the 30-amino-acid leader were not critical for import. The signal peptides of Escherichia coli β-lactamase and Bacillsus subtilis lipase could not carry proteins into mitochondria. Presumably, the Toho-1 leader can adopt a structure compatible for recognition by the import apparatus.Received 29 April 2005; received after revision 8 June 2005; accepted 17 June 2005 相似文献
15.
R. J. S. Viana A. F. Nunes R. E. Castro R. M. Ramalho J. Meyerson S. Fossati J. Ghiso A. Rostagno C. M. P. Rodrigues 《Cellular and molecular life sciences : CMLS》2009,66(6):1094-1104
The vasculotropic E22Q mutant of the amyloid-β (Aβ) peptide is associated with hereditary cerebral hemorrhage with amyloidosis
Dutch type. The cellular mechanism(s) of toxicity and nature of the AβE22Q toxic assemblies are not completely understood.
Comparative assessment of structural parameters and cell death mechanisms elicited in primary human cerebral endothelial cells
by AβE22Q and wild-type Aβ revealed that only AβE22Q triggered the Bax mitochondrial pathway of apoptosis. AβE22Q neither
matched the fast oligomerization kinetics of Aβ42 nor reached its predominant β-sheet structure, achieving a modest degree
of oligomerization with a secondary structure that remained a mixture of β and random conformations. The endogenous molecule
tauroursodeoxycholic acid (TUDCA) was a strong modulator of AβE22Q-triggered apoptosis but did not significantly change the
secondary structures and fibrillogenic propensities of Aβ peptides. These data dissociate the pro-apoptotic properties of
Aβ peptides from their distinct mechanisms of aggregation/fibrillization in vitro, providing new perspectives for modulation of amyloid toxicity.
Received 20 November 2008; received after revision 12 December 2008; accepted 12 January 2009 相似文献
16.
Eriste E Norberg A Bonetto V Nepomuceno D Lovenberg TW Sillard R Jörnvall H 《Cellular and molecular life sciences : CMLS》1999,56(7-8):709-713
A C-terminally elongated form of peptide histidine isoleucine amide (PHI) was isolated from porcine intestine based on its effect on cAMP production in IMR-32 cells. The structure was determined by amino acid sequence analysis of tryptic fragments and by mass spectrometry. The peptide has 42 amino acid residues like those described from human, rat and mouse, but the amino acid sequence of the C-terminal extension of pig PHI is unique. Unlike the other peptides, it has a C-terminal Ala and it differs at five positions from the human form and at six positions from the rat form, while the human and the rat forms differ by only two substitutions. To avoid confusion arising from different C-terminal residues, a unifying nomenclature is proposed: PHI-27 for the hormone and PHI-42 for the elongated product. 相似文献
17.
Summary Testis-specific histone TH2B from rat testis showed a very similar tryptic peptide map to somatic H2B from rat liver, indicating a common evolutionary origin. However, 5 peptide differences were detected between the 2 proteins, and the amino acid compositions of these distinctive peptides were determined.Supported by Grant 780-0609 from the Ford Foundation. 相似文献
18.
K. R. Weiss V. Březina E. C. Cropper S. L. Hooper M. W. Miller W. C. Probst F. S. Vilim I. Kupfermann 《Cellular and molecular life sciences : CMLS》1992,48(5):456-463
Despite their ubiquitous presence in the central and peripheral nervous systems, the behavioral functions of peptide co-transmitters remain to be elucidated. The marine molluscAplysia, whose simple nervous system facilitates the study of the neural basis of behavior, was used to investigate the role of peptidergic co-transmission in feeding behavior. Several novel modulatory neuropeptides were purified, and localized to identified cholinergic motorneurons. Physiological and biochemical studies demonstrated that these peptides are released when the motorneourons fire at frequencies that occur during normal behavior, and that the peptides modify the relationship between muscle contraction amplitude and relaxation rate so as to maintain optimal motor output when the intensity and frequency of feeding behavior change. 相似文献
19.
20.
Irena Crnković-Mertens Julia Bulkescher Christina Mensger Felix Hoppe-Seyler Karin Hoppe-Seyler 《Cellular and molecular life sciences : CMLS》2010,67(11):1895-1905
Livin (ML-IAP) is a cancer-associated member of the inhibitor of apoptosis protein (IAP) family. By yeast two-hybrid screening
of a randomized peptide expression library, we isolated short linear peptides that specifically bind to Livin, but not to
other IAPs. Intracellular expression of the peptides sensitized livin-expressing cancer cells toward different pro-apoptotic stimuli. The bioactive peptides neither showed sequence homologies
to Smac-derived IAP inhibitors, nor did they interfere with the binding of Livin to Smac. Intracellular expression of the
peptides did not affect the levels or the subcellular distribution of Livin. Growth of livin-expressing tumor cells was inhibited in colony formation assays by the Livin-targeting peptides. These findings provide evidence
that the targeted inhibition of Livin by peptides represents a viable approach for the apoptotic sensitization and growth
inhibition of tumor cells. The inhibitory peptides isolated here could form a novel basis for the development of therapeutically
useful Livin inhibitors. 相似文献