| 21064314 |
The effect of xanthines and pituitrin on water loss |
None |
Fed Proc |
The effect of xanthines and pituitrin on water loss
Abstract
|
| 21064704 |
Two antibiotics produced by Actinomyces isolated from soil |
None |
J Bacteriol |
Two antibiotics produced by Actinomyces isolated from soil
Abstract
|
| 21070025 |
Antifungal cyclic peptides from Psammosilene tunicoides |
10.1021/np100363a. |
J Nat Prod |
Antifungal cyclic peptides from Psammosilene tunicoides
Abstract
- Three new cyclic peptides, tunicyclins B-D, and a known cyclic peptide, psammosilenin B, were isolated from the root of Psammosilene tunicoides. The structures of new cyclic peptides were elucidated by extensive NMR and MS analysis. Tunicyclin B contains an unusual α,β-dehydrotryptophan (Δ(Z)-Trp) residue, previously reported from marine sponges and bacteria. Tunicyclin D showed a broad spectrum of antifungal activity against Candida albicans (SC5314), Candida albicans (Y0109), Candida tropicalis, Candida parapsilosis, and Cryptococcus neoformans (BLS108) with MIC(80) values of 4.0, 16.0, 0.25, 1.0, and 1.0 μg mL(-1), respectively.
|
| 21126094 |
Eutypoids B-E produced by a Penicillium sp. strain from the North Sea |
10.1021/np100633k. |
J Nat Prod |
Eutypoids B-E produced by a Penicillium sp. strain from the North Sea
Abstract
- Crude extracts of the Penicillium sp. strain KF620 isolated from the North Sea showed antimicrobial activities against Xanthomonas campestris and Candida glabrata. Purification of the extracts led to the isolation of the new aromatic butenolides eutypoids B (1), C (2), D (3), and E (4). Their structures were elucidated by NMR spectroscopy and supported by HRESIMS and UV data. The antibacterial activity of the crude extracts was due to the presence of the known diketopiperazine fellutanine (cyclo(Trp-Trp)). The eutypoids were neither cytotoxic nor antibacterial, but inhibited the activity of glycogen synthase kinase-3β.
|
| 21139268 |
Two new antifungal cyclic lipopeptides from Bacillus marinus B-9987 |
10.1248/cpb.58.1630. |
Chem Pharm Bull (Tokyo) |
Two new antifungal cyclic lipopeptides from Bacillus marinus B-9987
Abstract
- Two new cyclic lipopeptides maribasins A (1) and B (2) were isolated from the fermentation broth of the marine microorganism Bacillus marinus B-9987 isolated from Suaeda salsa in Bohai coastline of P. R. China. Both structures were established to be cyclo (D-Pro-L-Gln-L-Asn-L-Ser-D-Asn¹-D-Tyr-D-Asn²-D-β-aminoisopentadecanoic acid) (1) and cyclo (D-Pro-L-Gln-L-Asn-L-Ser-D-Asn¹-D-Tyr-D-Asn²-D-β-aminoanteisopentadecanoic acid) (2) by spectroscopic analysis and exhibited broad-spectrum activity against phytopathogens by the antifungal bioassay.
|
| 21143680 |
Phosphate systemically inhibits development of arbuscular mycorrhiza in Petunia hybrida and represses genes involved in mycorrhizal functioning |
10.1111/j.1365-313X.2010.04385.x. |
Plant J |
Phosphate systemically inhibits development of arbuscular mycorrhiza in Petunia hybrida and represses genes involved in mycorrhizal functioning
Abstract
- Most terrestrial plants form arbuscular mycorrhiza (AM), mutualistic associations with soil fungi of the order Glomeromycota. The obligate biotrophic fungi trade mineral nutrients, mainly phosphate (P(i) ), for carbohydrates from the plants. Under conditions of high exogenous phosphate supply, when the plant can meet its own P requirements without the fungus, AM are suppressed, an effect which could be interpreted as an active strategy of the plant to limit carbohydrate consumption of the fungus by inhibiting its proliferation in the roots. However, the mechanisms involved in fungal inhibition are poorly understood. Here, we employ a transcriptomic approach to get insight into potential shifts in metabolic activity and symbiotic signalling, and in the defence status of plants exposed to high P(i) levels. We show that in mycorrhizal roots of petunia, a similar set of symbiosis-related genes is expressed as in mycorrhizal roots of Medicago, Lotus and rice. P(i) acts systemically to repress symbiotic gene expression and AM colonization in the root. In established mycorrhizal roots, P(i) repressed symbiotic gene expression rapidly, whereas the inhibition of colonization followed with a lag of more than a week. Taken together, these results suggest that P(i) acts by repressing essential symbiotic genes, in particular genes encoding enzymes of carotenoid and strigolactone biosynthesis, and symbiosis-associated phosphate transporters. The role of these effects in the suppression of symbiosis under high P(i) conditions is discussed.
|
| 21171145 |
Two novel antimicrobial peptides from skin secretions of the frog, Rana nigrovittata |
10.1002/psc.1309. |
J Pept Sci |
Two novel antimicrobial peptides from skin secretions of the frog, Rana nigrovittata
Abstract
- Two novel antimicrobial peptides with similarity to brevinin-2 family are purified and characterized from the skin secretions of the frog, Rana nigrovittata. Their amino acid sequences were determined as GAFGNFLKGVAKKAGLKILSIAQCKLSGTC (brevinin-2-RN1) and GAFGNFLKGVAKKAGLKILSIAQCKLFGTC (brevinin-2-RN2), respectively, by Edman degradation. Different from brevinin-2, which is composed of 33 amino acid residues (aa), both brevinin-2-RN1 and -RN2 contain 30 aa. Five cDNA sequences (Genbank accession numbers, EU136465-9) encoding precursors of brevinin-2-RN1 and -RN2 were screened from the skin cDNA library of R. nigrovittata. These precursors are composed of 72 aa including a predicted signal peptide, an acidic spacer peptide, and a mature brevinin-2-RN. Both brevinin-2-RN1 and -RN2 showed strong antimicrobial activities against gram-positive and gram-negative bacteria and fungi. The current work identified and characterized two novel antimicrobial peptides with unique primary structure.
|
| 21179510 |
Histidine domain-protein tyrosine phosphatase interacts with Grb2 and GrpL |
10.1371/journal.pone.0014339. |
PLoS One |
Histidine domain-protein tyrosine phosphatase interacts with Grb2 and GrpL
Abstract
- Background:
Histidine domain-protein tyrosine phosphatase (HD-PTP) plays a key role in vesicle trafficking and biogenesis. Although it is a large protein with at least five distinct structural domains, only a few of its interactors are presently known, and the significance of these interactions is largely obscure.
Methodology and results:
In this study we performed a yeast two-hybrid screening using a human colon cDNA library and found that Grb2 and GrpL are binding partners of HD-PTP. Co-immunoprecipitation, pull-down and immunocytochemistry experiments confirmed the interactions. We also discovered that the central proline-rich and histidine-rich domain of HD-PTP is responsible for these interactions.
Significance:
The interaction of HD-PTP with two adapters of the Grb2 family, essential for numerous signaling pathways, suggests that HD-PTP might be important for signaling through a plethora of receptors.
|
| 21193000 |
Identification and characterization of antimicrobial peptides from the skin of the endangered frog Odorrana ishikawae |
10.1016/j.peptides.2010.12.013. |
Peptides |
Identification and characterization of antimicrobial peptides from the skin of the endangered frog Odorrana ishikawae
Abstract
- The endangered anuran species, Odorrana ishikawae, is endemic to only two small Japanese Islands, Amami and Okinawa. To assess the innate immune system in this frog, we investigated antimicrobial peptides in the skin using artificially bred animals. Nine novel antimicrobial peptides containing the C-terminal cyclic heptapeptide domain were isolated on the basis of antimicrobial activity against Escherichia coli. The peptides were members of the esculentin-1 (two peptides), esculentin-2 (one peptide), palustrin-2 (one peptide), brevinin-2 (three peptides) and nigrocin-2 (two peptides) antimicrobial peptide families. They were named esculentin-1ISa, esculentin-1ISb, esculentin-2ISa, palustrin-2ISa, brevinin-2ISa, brevinin-2ISb, brevinin-2ISc, nigrocin-2ISa and nigrocin-2ISb. Peptide primary structures suggest a close relationship with the Asian odorous frogs, Odorrana grahami and Odorrana hosii. These antimicrobial peptides possessed a broad-spectrum of growth inhibition against five microorganisms (E. coli, Staphylococcus aureus, methicillin-resistant S. aureus, Bacillus subtilis and Candida albicans). Nine different cDNAs encoding the precursor proteins were also cloned and showed that the precursor proteins exhibited a signal peptide, an N-terminal acidic spacer domain, a Lys-Arg processing site and an antimicrobial peptide at the C-terminus.
|
| 21193822 |
Identification of Streptomyces sp. KH29, which produces an antibiotic substance processing an inhibitory activity against multidrug-resistant Acinetobacter baumannii |
None |
J Microbiol Biotechnol |
Identification of Streptomyces sp. KH29, which produces an antibiotic substance processing an inhibitory activity against multidrug-resistant Acinetobacter baumannii
Abstract
- The Actinomycete strain KH29 is antagonistic to the multidrug-resistant Acinetobacter baumannii. Based on the diaminopimelic acid (DAP) type, and the morphological and physiological characteristics observed through the use of scanning electron microscopy (SEM), KH29 was confirmed as belonging to the genus Streptomyces. By way of its noted 16S rDNA nucleotide sequences, KH29 was found to have a relationship with Streptomyces cinnamonensis. The production of an antibiotic from this strain was found to be most favorable when cultured with glucose, polypeptone, and yeast extract (PY) medium for 6 days at 27 degrees C. The antibiotic produced was identified, through comparisons with reported spectral data including MS and NMR as a cyclo(L-tryptophanyl-L-tryptophanyl). Cyclo(L-Trp-L-Trp), from the PY cultures of KH29, was seen to be highly effective against 41 of 49 multidrugresistant Acinetobacter baumannii. Furthermore, cyclo(LTrp- L-Trp) had antimicrobial activity against Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, Saccharomyces cerevisiae, Aspergillus niger, and Candida albicans, However, it was ineffective against Streptomyces murinus.
|
| 21194241 |
Discovery of cyclotides in the fabaceae plant family provides new insights into the cyclization, evolution, and distribution of circular proteins |
10.1021/cb100388j. |
ACS Chem Biol |
Discovery of cyclotides in the fabaceae plant family provides new insights into the cyclization, evolution, and distribution of circular proteins
Abstract
- Cyclotides are plant proteins whose defining structural features are a head-to-tail cyclized backbone and three interlocking disulfide bonds, which in combination are known as a cyclic cystine knot. This unique structural motif confers cyclotides with exceptional resistance to proteolysis. Their endogenous function is thought to be as plant defense agents, associated with their insecticidal and larval growth-inhibitory properties. However, in addition, an array of pharmaceutically relevant biological activities has been ascribed to cyclotides, including anti-HIV, anthelmintic, uterotonic, and antimicrobial effects. So far, >150 cyclotides have been elucidated from members of the Rubiaceae, Violaceae, and Cucurbitaceae plant families, but their wider distribution among other plant families remains unclear. Clitoria ternatea (Butterfly pea) is a member of plant family Fabaceae and through its usage in traditional medicine to aid childbirth bears similarity to Oldenlandia affinis, from which many cyclotides have been isolated. Using a combination of nanospray and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) analyses, we examined seed extracts of C. ternatea and discovered cyclotides in the Fabaceae, the third-largest family of flowering plants. We characterized 12 novel cyclotides, thus expanding knowledge of cyclotide distribution and evolution within the plant kingdom. The discovery of cyclotides containing novel sequence motifs near the in planta cyclization site has provided new insights into cyclotide biosynthesis. In particular, MS analyses of the novel cyclotides from C. ternatea suggest that Asn to Asp variants at the cyclization site are more common than previously recognized. Moreover, this study provides impetus for the examination of other economically and agriculturally significant species within Fabaceae, now the largest plant family from which cyclotides have been described.
|
| 21195767 |
Structural characterization and anti-HIV-1 activities of arginine/glutamate-rich polypeptide Luffin P1 from the seeds of sponge gourd (Luffa cylindrica) |
10.1016/j.jsb.2010.12.007. |
J Struct Biol |
Structural characterization and anti-HIV-1 activities of arginine/glutamate-rich polypeptide Luffin P1 from the seeds of sponge gourd (Luffa cylindrica)
Abstract
- Luffin P1, the smallest ribosome-inactivating peptide from the seeds of Luffa cylindrica was found to have anti-HIV-1 activity in HIV-1 infected C8166 T-cell lines and be able to bind with HIV Rev Response Element. Nuclear magnetic resonance spectroscopy revealed that the Luffin P1 comprises a helix-loop-helix motif, with the two alpha helices tightly associated by two disulfide bonds. Based on our findings, we conclude that unlike the well-studied ribosome-inactivating proteins, which exert their action through N-glycosidase activities, Luffin P1 demonstrates a novel inactivation mechanism probably through the charge complementation with viral or cellular proteins. Our work also provides a new scaffold for the design of novel inhibitors from a simple helical motif.
|
| 21239550 |
Entianin, a novel subtilin-like lantibiotic from Bacillus subtilis subsp. spizizenii DSM 15029T with high antimicrobial activity |
10.1128/AEM.01962-10. |
Appl Environ Microbiol |
Entianin, a novel subtilin-like lantibiotic from Bacillus subtilis subsp. spizizenii DSM 15029T with high antimicrobial activity
Abstract
- Lantibiotics, such as nisin and subtilin, are lanthionine-containing peptides that exhibit antimicrobial as well as pheromone-like autoinducing activity. Autoinduction is specific for each lantibiotic, and reporter systems for nisin and subtilin autoinduction are available. In this report, we used the previously reported subtilin autoinduction bioassay in combination with mass spectrometric analyses to identify the novel subtilin-like lantibiotic entianin from Bacillus subtilis subsp. spizizenii DSM 15029(T). Linearization of entianin using Raney nickel-catalyzed reductive cleavage enabled, for the first time, the use of tandem mass spectrometry for the fast and efficient determination of an entire lantibiotic primary structure, including posttranslational modifications. The amino acid sequence determined was verified by DNA sequencing of the etnS structural gene, which confirmed that entianin differs from subtilin at 3 amino acid positions. In contrast to B. subtilis ATCC 6633, which produces only small amounts of unsuccinylated subtilin, B. subtilis DSM 15029(T) secretes considerable amounts of unsuccinylated entianin. Entianin was very active against several Gram-positive pathogens, such as Staphylococcus aureus and Enterococcus faecalis. The growth-inhibiting activity of succinylated entianin (S-entianin) was much lower than that of unsuccinylated entianin: a 40-fold higher concentration was required for inhibition. For succinylated subtilin (S-subtilin), a concentration 100-fold higher than that of unsuccinylated entianin was required to inhibit the growth of a B. subtilis test strain. This finding was in accordance with a strongly reduced sensing of cellular envelope stress provided by S-entianin relative to that of entianin. Remarkably, S-entianin and S-subtilin showed considerable autoinduction activity, clearly demonstrating that autoinduction and antibiotic activity underlie different molecular mechanisms.
|
| 21241058 |
Biostructural features of additional jasplakinolide (jaspamide) analogues |
10.1021/np100721g. |
J Nat Prod |
Biostructural features of additional jasplakinolide (jaspamide) analogues
Abstract
- The cyclodepsipeptide jasplakinolide (1) (aka jaspamide), isolated previously from the marine sponge Jaspis splendens, is a unique cytotoxin and molecular probe that operates through stabilization of filamentous actin (F-actin). We have recently disclosed that two analogues of 1, jasplakinolides B (3) and E, were referred to the National Cancer Institute's (NCI) Biological Evaluation Committee, and the objective of this study was to reinvestigate a Fijian collection of J. splendens in an effort to find jasplakinolide congeners with similar biological properties. The current efforts have afforded six known jasplakinolide analogues (4-7, 9, 10), two structures requiring revision (8 and 14), and four new congeners of 1 (11-13, 15) including open-chain derivatives and structures with modified β-tyrosine residues. Compounds were evaluated for biological activity in the NCI's 60 cell line screen and in a microfilament disruption assay in both HCT-116 and HeLa cells. These two phenotypic screens provide evidence that each cytotoxic analogue, including jasplakinolide B (3), operates by modification of microfilaments. The new structure jasplakinolide V (13) has also been selected for study by the NCI's Biological Evaluation Committee. In addition, the results of a clonogenic dose-response study on jasplakinolide are presented.
|
| 21258366 |
Crosstalk between Arg 1175 methylation and Tyr 1173 phosphorylation negatively modulates EGFR-mediated ERK activation |
10.1038/ncb2158. |
Nat Cell Biol |
Crosstalk between Arg 1175 methylation and Tyr 1173 phosphorylation negatively modulates EGFR-mediated ERK activation
Abstract
- Epidermal growth factor receptor (EGFR) can undergo post-translational modifications, including phosphorylation, glycosylation and ubiquitylation, leading to diverse physiological consequences and modulation of its biological activity. There is increasing evidence that methylation may parallel other post-translational modifications in the regulation of various biological processes. It is still not known, however, whether EGFR is regulated by this post-translational event. Here, we show that EGFR Arg 1175 is methylated by an arginine methyltransferase, PRMT5. Arg 1175 methylation positively modulates EGF-induced EGFR trans-autophosphorylation at Tyr 1173, which governs ERK activation. Abolishment of Arg 1175 methylation enhances EGF-stimulated ERK activation by reducing SHP1 recruitment to EGFR, resulting in augmented cell proliferation, migration and invasion of EGFR-expressing cells. Therefore, we propose a model in which the regulatory crosstalk between PRMT5-mediated Arg 1175 methylation and EGF-induced Tyr 1173 phosphorylation attenuates EGFR-mediated ERK activation.
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