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排序方式: 共有126条查询结果,搜索用时 11 毫秒
101.
Sitty Nur Syafa Bakri Rajeswari K. Ramasamy Salmijah Surif 《The International Journal of Life Cycle Assessment》2010,15(8):837-841
Background, aim, and scope
Ballast is a device in a fluorescent lamp that supports the production of light. In this study, the environmental impacts of two types of Malaysian ballast, magnetic ballast and electronic ballast, were identified and compared using the life cycle assessment approach through the ISO 14040 (2005) series. 相似文献102.
The membrane interaction and solution conformation of two mutants of the β-hairpin antimicrobial peptide, protegrin-1 (PG-1), are investigated to understand the structural determinants of antimicrobial potency. One mutant, [A6,8,13,15] PG-1, does not have the two disulfide bonds in wild-type PG-1, while the other, [Δ4,18 G10] PG-1, has only half the number of cationic residues. 31P solid-state NMR lineshapes of uniaxially aligned membranes indicate that the membrane disorder induced by the three peptides decreases in the order of PG-1>[Δ4,18 G10] PG-1?[A6,8,13,15] PG-1. Solution NMR studies of the two mutant peptides indicate that [Δ4,18 G10] PG-1 preserves the β-hairpin fold of the wild-type peptide while [A6,8,13,15] PG-1 adopts a random coil conformation. These NMR results correlate well with the known activities of these peptides. Thus, for this class of peptides, the presence of a β-hairpin fold is more essential than the number of cationic charges for antimicrobial activity. This study indicates that 31P NMR lineshapes of uniaxially aligned membranes are well correlated with antimicrobial activity, and can be used as a diagnostic tool to understand the peptide-lipid interactions of these antimicrobial peptides. 相似文献
103.
Dr E. Rajeswari K. Chitra K. Seetharaman V. Sankaralingam 《Archives Of Phytopathology And Plant Protection》2013,46(3):213-220
Abstract Grapevine downy mildew is the most devastating disease throughout the world causing huge monetary losses. Twenty medicinal plant extracts and six phylloplane microfloras were evaluated for their efficacy against sporangial germination of grapevine downy mildew pathogen Plasmopara viticola in vitro. The results revealed that the Neem Seed Kernel Extract (NSKE) at 5% significantly inhibited the sporangial germination (75.36%) of P. viticola. Among the phylloplane microflora Pseudomonas fluorescens was highly effective in reducing the sporangial germination (64.26%). Post inoculation spraying of NSKE (5%) and P. fluorescens (0.2%) effectively inhibited the disease development in the greenhouse. Three sprays with NSKE (5%) and phylloplane P. fluorescens (0.2%): first spray after initial appearance of disease and the second and third at 10 day intervals were found to be promising in reducing disease incidence in the field. 相似文献
104.
Natural products are vital in drug discovery and the search for anticancer agents has been significant importance to the researchers for a long time. In the present study, aqueous leaf extract of Pouteria sapota (P.sapota) was evaluated for its cytotoxic activity. The leaf extract was preliminarily screened for antioxidant activity using DPPH method for Radical Scavenging Activity, Hydrogen Peroxide Scavenging Activity and Reducing Power Activity. Further, the aqueous leaf extract was screened for cytotoxic activity against breast cancer cell lines (MCF-7) in vitro. The results of the study showed that aqueous extract of the P.sapota leaf was rich in phytochemicals, antioxidant activity and showed a significant anti-cancer activity against tested MCF-7 cell lines. The present study was designed to evaluate the anticancer potential of P.sapota leaf. The antioxidants present in P.sapota have strong cytotoxic activity suggests that it can be considered for anti-cancer treatment. 相似文献
105.
Abhijit Dandapat Jagannath Bhattacharyya Srimonta Gayen Anirban Chakraborty Anannya Banga Rajeswari Mukherjee Chandi Charan Mandal Munshi Azad Hossain Samarjit Roy Asitava Basu Soumitra Kumar Sen 《Journal of plant biochemistry and biotechnology.》2014,23(1):81-92
The primary technical constraint plant scientists face in generating insect resistant transgenic crops with insecticidal Bacillus thuringiensis (Bt) crystal protein (Cry) genes remains failing to generate sufficiently large numbers of effective resistant transgenic plant lines. One possible means to overcome this challenge is through deployment of a Cry toxin gene that contains high levels of insecticidal specific activity for target insect pests. In the present study, we tested this hypothesis using a natural variant of the Cry1Ab toxin under laboratory conditions that possessed increased insecticidal potency against the yellow stem borer (YSB, Scirpophaga incertulus), one of the most damaging rice insect pests. Following adoption of a stringent selection strategy for YSB resistant transgenic rice lines under field conditions, results showed recovery of a significantly higher number of YSB resistant independent transgenic plant lines with the variant cry1Ab gene relative to transgenic plant lines harbouring cry1Ab berliner gene. Structural homology modelling of the variant toxin peptide with the Cry1Aa toxin molecule, circular dichroism spectral analysis, and hydropathy plot analysis indicated that serine substitution by phenylalanine at amino acid position 223 of the Cry1Ab toxin molecule resulted in a changed role for α-helix 7 in domain I of Cry1Ab for enhanced toxicity. 相似文献
106.
107.
108.
Ameloblasts synthesize and secrete the enamel matrix proteins (amelogenin, ameloblastin, and enamelin). This investigation examined the profiles of ameloblastin in the ameloblasts and in the enamel matrix during different postnatal (PN) days (days 0-9) of development of mouse molar, using an antibody specific for C-terminal sequence of ameloblastin (Ct; GNKVHQPQVHNAWRF). Ameloblastin is found in three different molecular sizes (37, 55, and 66 kDa) in both ameloblasts and enamel matrix during PN development. In the ameloblasts, the sequence of expression of these fractions varied. The 37-kDa fraction was observed (even before the appearances of mRNA of the proteases, enamelysin and kallikrein-4) on days 0 and 1, persisted until day 3, and was not found thereafter. Other isoforms (55 and 66 kDa) distinctly appeared in ameloblasts after day 1, reached a peak on day 5, and remained thereafter. The Ct-positive granules appeared beaded in the ameloblasts on day 3. In the extracellular matrix, a 37-kDa (but not 66- or 55-kDa) fraction was detected on days 0 and 1 and remained in the matrix throughout the PN days. The larger isoforms (55 and 66 kDa) appeared in the enamel matrix from day 3 onward. On days 0-3, but not later, the 37-kDa isoform co-localizes with amelogenin in Tomes' process and formative enamel, as revealed by laser scan confocal microscopy. Autoradiography confirmed accumulation of 3H-labeled amelogenin trityrosyl motif peptide in the region of Tomes' process and formative enamel from day 0 to 3. These observations suggest that the 37-kDa isoform interacts with amelogenin during early tooth development. 相似文献
109.
A feed-forward repression mechanism anchors the Sin3/histone deacetylase and N-CoR/SMRT corepressors on chromatin 总被引:3,自引:0,他引:3 下载免费PDF全文
110.
Ognian C. Ikonomov Jason Fligger Diego Sbrissa Rajeswari Dondapati Krzysztof Mlak Robert Deeb Assia Shisheva 《The Journal of biological chemistry》2009,284(6):3750-3761
JIPs (c-Jun N-terminal kinase interacting
proteins), which scaffold JNK/p38 MAP kinase signaling modules,
also bind conventional kinesins and are implicated in microtubule-based
membrane trafficking in neuronal cells. Here we have identified a novel splice
variant of the Jip4 gene product JLPL (JNK-interacting
leucine zipper protein) in yeast-two hybrid screens with the phosphoinositide
kinase PIKfyve. The interaction was confirmed by pulldown and
coimmunoprecipitation assays in native cells. It engages the PIKfyve
cpn60_TCP1 consensus sequence and the last 75 residues of the JLP C terminus.
Subpopulations of both proteins cofractionated and populated similar
structures at the cell perinuclear region. Because PIKfyve is essential in
endosome-to-trans-Golgi network (TGN) cargo transport, we tested whether JLP
is a PIKfyve functional partner in this trafficking pathway. Short interfering
RNA (siRNA)-mediated depletion of endogenous JLP or PIKfyve profoundly delayed
the microtubule-based transport of chimeric furin (Tac-furin) from endosomes
to the TGN in a CHO cell line, which was rescued upon ectopic expression of
siRNA-resistant JLP or PIKfyve constructs. Peptides from the contact sites in
PIKfyve and JLP, or a dominant-negative PIKfyve mutant introduced into cells
by ectopic expression or microinjection, induced a similar defect. Because
Tac-TGN38 delivery from endosomes to the TGN, unlike that of Tac-furin, does
not require intact microtubules, we monitored the effect of JLP and PIKfyve
depletion or the interacting peptides administration on Tac-TGN38 trafficking.
Remarkably, neither maneuver altered the Tac-TGN38 delivery to the TGN. Our
data indicate that JLP interacts with PIKfyve and that both proteins and their
association are required in microtubule-based, but not in
microtubule-independent, endosome-to-TGN cargo transport.In mammalian cells, the endosomal/endocytic system comprises an
interconnected and morphologically complex network of membrane organelles that
supports fundamental functions such as nutrient entry and delivery for
degradation, removal and degradation of plasma membrane or Golgi proteins,
regulation and integration of signaling pathways, and protein recycling to the
cell surface or the
TGN2
(1–4).
From the plasma membrane, the endocytosed cargo is first delivered to early
endosomes/sorting endosomes. Cargoes destined for recycling to the cell
surface then enter the endocytic recycling compartment, whereas others,
intended for degradation, remain in early endosomes. Early endosomes undergo a
series of changes, known as maturation, to give rise to maturing transport
intermediates (herein ECV/MVBs; also Ref.
5) and to late endosomes that
fuse with lysosomes to deliver cargo for degradation. Recycling or degradation
is not the only outcome of the cell surface-originated cargoes. A set of
internalized transmembrane proteins, including intracellular sorting
receptors, enzymes, and toxins, are retrieved from the endosomal system and
transported to the TGN. The endosome-to-TGN trafficking of the
acid-hydrolase-sorting receptor, CI-MPR, the endopeptidase furin, and the
putative cargo receptor TGN38 are the best studied examples. These cargoes are
highly enriched in the TGN at steady state but arrive there from different
compartments, utilizing distinct mechanisms. Thus, TGN38 enters the TGN from
the endocytic recycling compartment by an iterative removal from the latter
compartment, furin reaches the TGN by exiting the early/late endosomal system,
and CI-MPR implements features of both pathways
(4,
6–9).Whereas the detailed molecular and cellular mechanisms underlying the
membrane progression in the course of cargo transport through the endosomal
system or retrieval from early/late endosomes to the TGN is still elusive,
experimental evidence has been accumulating to implicate PIKfyve, the sole
enzyme for PtdIns(3,5)P2 synthesis
(10). Thus, PIKfyve has been
found to interact with the late endosome-to-TGN transport factor Rab9 effector
p40 (11). Furthermore,
disruption of the PtdIns(3,5)P2 homeostatic mechanism by means of
expression of dominant-negative kinase-deficient point mutants of PIKfyve,
protein depletion, or pharmacological inhibition of PIKfyve activity was found
to impair the exit of a subset of cargoes from early endosomes to the TGN and
late endosomes or from the late endosomes
(12–16).
Phenotypically, these defects are manifested by progressive endosome swelling
and cytoplasmic vacuolation, first seen by expression of dominant-negative
PIKfyveK1831E in a number of mammalian cell types
(17) and confirmed thereafter
by other maneuvers inhibiting PIKfyve protein expression or activity
(14,
16). In vitro
reconstitution assays indicate that PIKfyve enzymatic activity is required in
endosome processing in two ways. It triggers the formation/fission (or
maturation) of ECV/MVBs from early endosomes and arrests the rate of fusion
events in the endosomal system
(18,
19). It is thus conceivable
that impaired PIKfyve and PtdIns(3,5)P2 functioning in the fission
and fusion events mechanistically underlies the constraints in the trafficking
pathways traversing endosomes.Microtubules aided by the microtubule-associated motor protein families of
kinesin and dynein are required for proper performance of the
endosomal/endocytic membrane system. Although their role is rather complex and
not completely understood, in vivo and in vitro studies
implicate microtubule-based dynamics in multiple aspects of the endocytic
trafficking, including sorting of endocytic contents, fission/fusion events at
early or late endosomes, early endosome maturation, and efficient motility of
the transport vesicles to their destination
(20–27).
Accumulating evidence indicates that the binding of motor proteins to
organelles or carrier vesicles is regulated by motor protein adapters.
Intriguingly, this newly emerging adapter function has been found to be
executed by proteins known as scaffolds of stress signaling enzymes. One such
adapter for conventional kinesins is the group of JIPs that scaffold the
JNK/p38 MAP kinase signaling modules
(28–31).
A mutation that causes mislocalization of synaptic vesicles and aberrant
axonal transport in Drosophila and Caenorhabditis elegans
affects the JIP3 homologs Sunday driver (dSYD) and Unc16,
respectively (32,
33). In mammalian cells, JIPs
are represented by four proteins (JIP1–4) derived from separate genes
and several alternatively spliced variants. JIP1, the founding member, is
structurally related to JIP2
(34,
35). JIP3 (also known as
Unc16/JSAP1/dSYD) is structurally unrelated to JIP1 or JIP2, but as those two,
it is abundant in neuronal cells
(30,
32,
36). The latest addition to
the group is JIP4 that occurs in three splice variants known thus far: JLP and
JIP4 in mouse and SPAG9 in humans
(31,
37,
38). JIP4, JLP, and SPAG9
(gene symbol, SPAG9) are structurally homologous to JIP3 but display
broader distribution
(37–39).
Remarkably, all four members of the JIP group interact with the kinesin1 light
chain, and potential cargoes for microtubule-based vesicle transport have been
proposed for JIP1–JIP3
(32,
33,
38,
40–43).
The role of JLP/JIP4 in the context of cargo transport or membrane trafficking
events, however, has never been investigated. In the present study we report
that JLP is a PIKfyve physical and functional partner in microtubule-based
endosome-to-TGN trafficking. The interaction is identified by a yeast
two-hybrid screen with the PIKfyve cpn60_TCP1 consensus sequence and mapped to
the 75-aa peptide fragment of the extreme JLP C terminus. By monitoring
divergent routes of cargo delivery to the TGN, differing by the requirement of
microtubule-dependent early endosome maturation, we have determined that JLP
assists PIKfyve selective functionality in microtubule-based endosome-to-TGN
trafficking. 相似文献