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61.
Curry WJ McCollum AP Brockbank S Gardiner TA Maule AG Stitt AW 《Regulatory peptides》2003,113(1-3):41-47
WE-14 is derived from the cell-specific posttranslational processing of chromogranin A (CgA) in subpopulations of neuroendocrine cells and neurons. Region- and site-specific chromogranin A, pancreastatin and WE-14 antisera were employed to study the generation of WE-14 in porcine ocular tissues. No chromogranin A or pancreastatin immunostaining was detected in ocular tissue. Immunohistochemistry detected WE-14 immunostaining in a network of nerve fibre bundles and nerve fibres throughout the limbus, cornea, iris and ciliary body with sparse nerve fibres detected throughout the choroid and sclera. Retinal analysis detected intense WE-14 immunostaining in large ovoid cells in the ganglion cell layer with weak immunostaining in a population of small cells in the inner nuclear layer; weak immunostaining was detected within the fibre layers in the inner plexiform layer. Quantitatively, the highest WE-14 tissue concentration was recorded in aqueous retinal and corneal extracts with lower concentrations in the sclera, choroid and anterior uveal tissues. Chromatographic profiling resolved a minor chromogranin A-like immunoreactant and a predominant immunoreactant co-eluting with synthetic human WE-14. This is the first study to demonstrate that WE-14 is generated in neuronal fibres primarily innervating the anterior chamber and in select cell populations in the retina. 相似文献
62.
Grapefruit, Citrus paradisi, were injured, inoculated with Penicillium digitatum and incubated under conditions favourable for the accumulation of defence related material. Histochemical examination revealed that tissues adjacent to inoculated injuries contained phloroglucinol-HCl (PG-HCl) reactive material. Solvent washed cell wall preparations of intact and injured-inoculated peel were further purified using a mixture of cell wall degrading enzymes. Samples from injured inoculated tissue contained PG-HCl reactive globular material in addition to the fragments of xylem and cuticle found in controls. The principal chemical moieties of the material that accumulates in grapefruit injuries during wound-healing were studied by solid state 13C cross-polarization magic angle spinning NMR. A complete assignment of the NMR signals was made. From the analysis evidence was found that cellulose and hemicellulose are the biopolymers present in the intact peel samples, in addition, relevant quantities of cutin were found in the residues of enzyme digest. The NMR difference spectrum intact- wounded peels showed resonances which were attributed to all major functional groups of the aromatic-aliphatic suberin polyester of new material produced by the wounds. Information on the latter polyester was obtained by analyzing the T(1)rho (1H) relaxation. 相似文献
63.
Citrus fruits are sensitive to low temperatures and this often results in the development of chilling injuries during postharvest storage. In order to gain more insight into the molecular mechanisms involved in the acquisition of fruit chilling tolerance, we initiated a grapefruit ( Citrus paradisi, cv. Marsh Seedless) flavedo cDNA sequencing project and used it to identify a cDNA similar to other Poncirus trifoliata and Citrus unshiu dehydrin genes reported to be responsive to low temperatures. The grapefruit dehydrin cDNA, designated cor15 , encodes a predicted polypeptide of 15.1 kDa, that is almost completely identical with other reported citrus dehydrin proteins, except that it contains two large amino acid repeats, whereas P. trifoliata COR11 has only one such repeat and P. trifoliata COR19 and C. unshiu COR19 have three repeats. Together, the various grapefruit, P. trifoliata and C. unshiu dehydrins form a closely related and unique dehydrin gene family that differs from most other plant dehydrins in having an unusual K-segment similar to that of gymnosperms and in having a serine cluster (S-segment) at an unusual position at the carboxy-terminus. The grapefruit cor15 gene is consistently expressed in the fruit peel tissue at harvest, but its message levels dramatically decrease during storage at 2°C. However, a pre-storage hot water treatment, which enhances fruit chilling tolerance, elicited retention of the constant level of cor15 gene expression during cold storage and eliminated its decline. The hot water treatment had no inductive effect on cor15 gene expression when the fruit were held at non-chilling temperatures. The effects of other stresses, such as exposure to ethylene, UV irradiation and wounding, on cor15 gene expression, were temporary and persisted for 1-2 days after the treatments. 相似文献
64.
Females of the sea urchin Strongylocentrotus purpuratus differ in the structures of their egg jelly sulfated fucans 总被引:1,自引:0,他引:1
The egg jelly coats of sea urchins contain sulfated fucans which bind to a
sperm surface receptor glycoprotein to initiate the signal transduction
events resulting in the sperm acrosome reaction. The acrosome reaction is
an ion channel regulated exocytosis which is an obligatory event for sperm
binding to, and fusion with, the egg. Approximately 90% of individual
females of the sea urchin Strongylocentrotus purpuratus spawned eggs having
only one of two possible sulfated fucan electrophoretic isotypes, a slow
migrating (sulfated fucan I), or a fast migrating (sulfated fucan II)
isotype. The remaining 10% of females spawned eggs having both sulfated
fucan isotypes. The two sulfated fucan isotypes were purified from egg
jelly coats and their structures determined by NMR spectroscopy and
methylation analysis. Both sulfated fucans are linear polysaccharides
composed of 1-->3-linked alpha-L-fucopyranosyl units. Sulfated fucan I
is entirely sulfated at the O -2 position but with a heterogeneous
sulfation pattern at O -4 position. Sulfated fucan II is composed of a
regular repeating sequence of 3 residues, as follows: [3-alpha-L-Fuc p -
2,4(OSO3)-1-->3-alpha-L-Fuc p -4(OSO3)-1-->3-alpha-L-Fuc p -4(OSO3)-
1]n. Both purified sulfated fucans have approximately equal potency in
inducing the sperm acrosome reaction. The significance of two structurally
different sulfated fucans in the egg jelly coat of this species could
relate to the finding that the sperm receptor protein which binds sulfated
fucan contains two carbohydrate recognition modules of the C-type lectin
variety which differ by 50% in their primary structure.
相似文献
65.
Fucose is a major constituent of the protein- and lipid-linked glycans of
the various life-cycle stages of schistosomes. These fucosylated glycans
are highly antigenic and seem to play a role in the pathology of
schistosomiasis. In this article we describe the identification and
characterization of two fucosyltransferases (FucTs) in cercariae of the
avian schistosome Trichobilharzia ocellata, a GDP-Fuc:[Galbeta1--
>4]GlcNAcbeta-R alpha1-->3-FucT and a novel GDP-Fuc:Fucalpha-R
alpha1-- >2-FucT. Triton X-100 extracts of cercariae were assayed for
FucT activity using a variety of acceptor substrates. Type 1 chain
(Galbeta1- ->3GlcNAc) based compounds were poor acceptors, whereas those
based on a type 2 chain (Galbeta1-->4GlcNAc), whether
alpha2'-fucosylated, alpha3'-sialylated, or unsubstituted, and whether
present as oligosaccharide or contained in a glycopeptide or glycoprotein,
all served as acceptor substrates. In this respect the schistosomal alpha3-
FucT resembles human FucT V and VI rather than other known FucTs. N-
ethylmaleimide, an inhibitor of several human FucTs, had no effect on the
activity of the schistosomal alpha3-FucT, whereas GDP-beta-S was strongly
inhibitory. Large scale incubations were carried out with
Galbeta1-->4GlcNAc, GalNAcbeta1-->4GlcNAcbeta-O -(CH2)8COOCH3 and
Fucalpha1-->3GlcNAcbeta1-->2Man as acceptor substrates and the
products of the incubations were isolated using a sequence of
chromatographic techniques. By methylation analysis and 2D-TOCSY and
ROESY1H-NMR spectroscopy the products formed were shown to be Galbeta1--
>4[Fucalpha1-->2Fucalpha1-->3]GlcNAc,
GalNAcbeta1-->4[Fucalpha1-- >2Fucalpha1-->3]GlcNAcbe
ta-O-(CH2)8COOCH3, and Fucalpha1-->2Fucalpha1--
>3GlcNAcbeta1-->2Man, respectively. It is concluded that the alpha2-
FucT and alpha3-FucT are involved in the biosynthesis of the (oligomeric)
Lewisx sequences and the Fucalpha1-->2Fucalpha1-->3GlcNAc structural
element that have been described on schistosomal glycoconjugates.
相似文献
66.
Surface kinetic test method for determining rate of kill by an antimicrobial solid. 总被引:5,自引:3,他引:2 下载免费PDF全文
An antimicrobial-surface kinetic test which maximizes probability of cell-to-surface contact has been developed. The measurement of rate of kill by a nonleaching antimicrobial surface is based on the number of surviving bacterial cells at specific times of exposure to various amounts of total treated surface area of test substrate. This method gives information for direct comparison of rate of kill for a variety of antimicrobial surfaces in terms of rate of kill per square centimeter of surface area. Data obtained by this method can also give valuable dose response application information as an indication of the exponential efficiency of concentration in terms of treated surface area. 相似文献
67.
68.
The exocyclic amine protecting groups in oligonucleotide synthesis which require 8-16 hours at 55 degrees C for deprotection in ammonia have been replaced with more labile base protecting groups (dimethylformamidine for adenine and guanine and isobutyryl for cytosine). Using these fast oligonucleotide deprotecting groups which require 2-3 hours at 55 degrees C for complete deprotection, a new set of cyanoethyl phosphoramidite ribonucleoside monomers and supports has been developed. Ribozymes and substrate RNAs which were synthesized with these phosphoramidites were assayed and were found to have full catalytic (biological) activity. 相似文献
69.
70.
The Arp2/3 complex is an essential component of the actin cytoskeleton in yeast and is required for the movement of actin patches. In an attempt to identify proteins that interact with this complex in the fission yeast Schizosaccharomyces pombe, we sought high-copy suppressors of the S. pombe arp3-c1 mutant, and have identified one, which we have termed asp1(+). The asp1(+) open reading frame (ORF) predicts a highly conserved protein of 921 amino acids with a molecular mass of 106 kD that does not contain motifs of known function. Neither asp1(+) nor its apparent Saccharomyces cerevisiae ortholog, VIP1, are essential genes. However, disruption of asp1(+) leads to altered morphology and growth properties at elevated temperatures and defects in polarized growth. The asp1 disruption strain also is hypersensitive to Ca+ ions and to low pH conditions. Although Asp1p is not stably associated with the Arp2/3 complex nor localized in any discrete structure within the cytoplasm, the asp1 disruption mutant was synthetically lethal with mutations in components of the Arp2/3 complex, arp3-c1 and sop2-1, as well as with a mutation in actin, act1-48. Moreover, the vip1 disruption strain showed a negative genetic interaction with a las17Delta strain. We conclude that Asp1p/Vip1p is important for the function of the cortical actin cytoskeleton. 相似文献