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1.
2.
Cloning, Expression in Escherichia coli, and
Characterization of Arabidopsis thaliana UMP/CMP
Kinase 总被引:1,自引:0,他引:1
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A cDNA encoding the Arabidopsis thaliana uridine 5′-monophosphate (UMP)/cytidine 5′-monophosphate (CMP) kinase was isolated by complementation of a Saccharomyces cerevisiae ura6 mutant. The deduced amino acid sequence of the plant UMP/CMP kinase has 50% identity with other eukaryotic UMP/CMP kinase proteins. The cDNA was subcloned into pGEX-4T-3 and expressed as a glutathione S-transferase fusion protein in Escherichia coli. Following proteolytic digestion, the plant UMP/CMP kinase was purified and analyzed for its structural and kinetic properties. The mass, N-terminal sequence, and total amino acid composition agreed with the sequence and composition predicted from the cDNA sequence. Kinetic analysis revealed that the UMP/CMP kinase preferentially uses ATP (Michaelis constant [Km] = 29 μm when UMP is the other substrate and Km = 292 μm when CMP is the other substrate) as a phosphate donor. However, both UMP (Km = 153 μm) and CMP (Km = 266 μm) were equally acceptable as the phosphate acceptor. The optimal pH for the enzyme is 6.5. P1, P5-di(adenosine-5′) pentaphosphate was found to be a competitive inhibitor of both ATP and UMP. 相似文献
3.
4.
Barrie J. Anthony Kylie R. James Geoffrey N. Gobert Grant A. Ramm Donald P. McManus 《PloS one》2013,8(6)
Hepatic fibrosis induced by egg deposition is the most serious pathology associated with chronic schistosomiasis, in which the hepatic stellate cell (HSC) plays a central role. While the effect of Schistosoma mansoni eggs on the fibrogenic phenotype of HSCs has been investigated, studies determining the effect of eggs of
S
. japonicum
on HSCs are lacking. Disease caused by
S
. japonicum
is much more severe than that resulting from S. mansoni infection so it is important to compare the pathologies caused by these two parasites, to determine whether this phenotype is due to the species interacting differently with the mammalian host. Accordingly, we investigated the effect of
S
. japonicum
eggs on the human HSC cell line, LX-2, with and without TGF-β (Transforming Growth Factor beta) co-treatment, so as to determine the impact on genes associated with fibrogenesis, inflammation and matrix re-organisation. Activation status of HSCs was assessed by αSMA (Alpha Smooth Muscle Actin) immunofluorescence, accumulation of Oil Red O-stained lipid droplets and the relative expression of selected genes associated with activation. The fibrogenic phenotype of HSCs was inhibited by the presence of eggs both with or without TGF-β treatment, as evidenced by a lack of αSMA staining and reduced gene expression of αSMA and Col1A1 (Collagen 1A1). Unlike S. mansoni-treated cells, however, expression of the quiescent HSC marker PPAR-γ (Peroxisome Proliferator-Activated Receptor gamma) was not increased, nor was there accumulation of lipid droplets. In contrast,
S
. japonicum
eggs induced the mRNA expression of MMP-9 (Matrix Metalloproteinase 9), CCL2 (Chemokine (C-C motif) Ligand 2) and IL-6 (Interleukin 6) in HSCs indicating that rather than inducing complete HSC quiescence, the eggs induced a proinflammatory phenotype. These results suggest HSCs in close proximity to
S
. japonicum
eggs in the liver may play a role in the proinflammatory regulation of hepatic granuloma formation. 相似文献
5.
Greenhouse and field experiments were conducted to determine the effects of phenamiphos and/or alachlor on early growth of soybean, root morphology, and infection and resurgence of Heterodera glycines (race 1). All tests were planted to ''Ransom'' soybeans. In greenhouse experiments without nematodes, root growth was inhibited at 5 days by alachlor treatments and at 10 days by phenamiphos treatments; with nematodes, phenamiphos treatments enhanced root growth. Phenamiphos also suppressed early penetration of soybean roots by H. glycines in the greenhouse. Early soybean growth parameters among treatments were generally similar in the field. Nematode penetration was limited with treatments containing phenamiphos at one location. Plants treated with only alachlor had less nematode infection than did the control; however, plants treated with herbicide/nematicide combinations had more nematode penetration than did plants treated with phenamiphos alone. Alterations of root growth and interference with the efficacy of phenamiphos are two processes by which alachlor may enhance soybean susceptibility or suitability to H. glycines. 相似文献
6.
Zygosaccharomyces rouxii is a fructophilic yeast than can grow at very high sugar concentrations. We have identified an ORF encoding a putative fructose/H+ symporter in the Z. rouxii CBS 732 genome database. Heterologous expression of this ORF in a S. cerevisiae strain lacking its own hexose transporters (hxt-null) and subsequent kinetic characterization of its sugar transport activity showed it is a high-affinity low-capacity fructose/H+ symporter, with Km 0.45±0.07 mM and Vmax 0.57±0.02 mmol h−1 (gdw) −1. We named it ZrFsy1. This protein also weakly transports xylitol and sorbose, but not glucose or other hexoses. The expression of ZrFSY1 in Z. rouxii is higher when the cells are cultivated at extremely low fructose concentrations (<0.2%) and on non-fermentable carbon sources such as mannitol and xylitol, where the cells have a prolonged lag phase, longer duplication times and change their microscopic morphology. A clear phenotype was determined for the first time for the deletion of a fructose/H+ symporter in the genome where it occurs naturally. The effect of the deletion of ZrFSY1 in Z. rouxii cells is only evident when the cells are cultivated at very low fructose concentrations, when the ZrFsy1 fructose symporter is the main active fructose transporter system. 相似文献
7.
The hesionid polychaete genera Oxydromus Grube, 1855 and Ophiodromus Sars, 1862 have been regarded as synonyms with the former considered as invalid since it was thought to be a junior homonym of Oxydromus Schlegel, 1854. However, Schlegel’s name is an incorrect subsequent spelling for Ocydromus Wagler, 1830 (Aves, Gruiformes, Rallidae) and is not an available name. Consequently, Oxydromus Grube, 1855 must be reinstated for this hesionid polychaete genus. A check-list of valid species of Oxydromus including 30 new combinations is provided. 相似文献
8.
9.
Christopher P. Gayer Lakshmi S. Chaturvedi Shouye Wang David H. Craig Thomas Flanigan Marc D. Basson 《The Journal of biological chemistry》2009,284(4):2001-2011
The intestinal epithelium is repetitively deformed by shear, peristalsis,
and villous motility. Such repetitive deformation stimulates the proliferation
of intestinal epithelial cells on collagen or laminin substrates via ERK, but
the upstream mediators of this effect are poorly understood. We hypothesized
that the phosphatidylinositol 3-kinase (PI3K)/AKT cascade mediates this
mitogenic effect. PI3K, AKT, and glycogen synthase kinase-3β
(GSK-3β) were phosphorylated by 10 cycles/min strain at an average 10%
deformation, and pharmacologic blockade of these molecules or reduction by
small interfering RNA (siRNA) prevented the mitogenic effect of strain in
Caco-2 or IEC-6 intestinal epithelial cells. Strain MAPK activation required
PI3K but not AKT. AKT isoform-specific siRNA transfection demonstrated that
AKT2 but not AKT1 is required for GSK-3β phosphorylation and the strain
mitogenic effect. Furthermore, overexpression of AKT1 or an AKT chimera
including the PH domain and hinge region of AKT2 and the catalytic domain and
C-tail of AKT1 prevented strain activation of GSK-3β, but overexpression
of AKT2 or a chimera including the PH domain and hinge region of AKT1 and the
catalytic domain and C-tail of AKT2 did not. These data delineate a role for
PI3K, AKT2, and GSK-3β in the mitogenic effect of strain. PI3K is
required for both ERK and AKT2 activation, whereas AKT2 is sequentially
required for GSK-3β. Furthermore, AKT2 specificity requires its catalytic
domain and tail region. Manipulating this pathway may prevent mucosal atrophy
and maintain the mucosal barrier in conditions such as ileus, sepsis, and
prolonged fasting when peristalsis and villous motility are decreased and the
mucosal barrier fails.Mechanical forces are part of the normal intestinal epithelial environment.
Numerous different forces deform these cells including shear stress from
endoluminal chyme, bowel peristalsis, and villous motility
(1,
2). During normal bowel
function the mucosa is subjected to injury that must be repaired to maintain
the mucosal barrier (3,
4). Deformation patterns of the
bowel are altered in conditions such as prolonged fasting, post-surgical
ileus, and sepsis states, resulting in profoundly reduced mucosal deformation.
When such states are prolonged, proliferation slows, the mucosa becomes
atrophic, and bacterial translocation may ensue as the mucosal barrier of the
gut breaks down
(5–7).In vitro, repetitive deformation is trophic for intestinal
epithelial cells (8) cultured
on type I or type IV collagen or laminin. Human Caco-2 intestinal epithelial
cells (9), non-transformed rat
IEC-6 intestinal epithelial cells
(10), and primary human
intestinal epithelial cells isolated from surgical specimens
(11) proliferate more rapidly
in response to cyclic strain
(12) unless substantial
quantities of fibronectin are added to the media or matrix
(11) to mimic the acute phase
reaction of acute or chronic inflammation and injury. Cyclic strain also
stimulates proliferation in HCT 116 colon cancer cells
(13) and differentiation of
Caco-2 cells cultured on a collagen substrate
(9). This phenomenon has also
been observed in vivo
(14). Thus, repetitive
deformation may help to maintain the normal homeostasis of the gut mucosa
under non-inflammatory conditions. Previous work in our laboratory has
implicated Src, focal adhesion kinase, and the mitogen-activated protein
kinase (MAPK)2
extracellular signal-related kinase (ERK) in the mitogenic effect of strain
(10). Although p38 is also
activated in Caco-2 cells subjected to cyclic strain on a collagen matrix, its
activity is not required for the mitogenic effect of strain
(12).Although often the PI3K/AKT pathway is thought of as a parallel pathway to
the MAPK, this is not always the case. Protein kinase C isoenzymes
differentially modulate thrombin effect on MAPK-dependent retinal pigment
epithelial cell (RPE) proliferation, and it has been shown that PI3K or AKT
inhibition prevented thrombin-induced ERK activation and RPE proliferation
(15).PI3K, AKT, and glycogen synthase kinase (GSK), a downstream target of AKT
(16), have been implemented in
intestinal epithelial cell proliferation in numerous cell systems not
involving strain
(17–19)
including uncontrolled proliferation in gastrointestinal cancers
(20–22).
Mechanical forces activate this pathway as well. PI3K and AKT are required for
increased extracellular pressure to stimulate colon cancer cell adhesion
(23), although the pathway by
which pressure stimulates colon cancer cells in suspension differs from the
response of adherent intestinal epithelial cells to repetitive deformation
(24), and GSK is not involved
in this effect.3
Repetitive strain also stimulates vascular endothelial cell proliferation via
PI3K and AKT (25,
26), whereas respiratory
strain stimulates angiogenic responses via PI3K
(27). We, therefore,
hypothesized that the PI3K/AKT/GSK axis would be involved in the mitogenic
effects of repetitive deformation on a collagen matrix.To test this hypothesis, we used the Flexcell apparatus to rhythmically
deform Caco-2 intestinal epithelial cells. IEC-6 cells were used to confirm
key results. A frequency of 10 cycles per min was used, which is similar in
order of magnitude to the frequency that the intestinal mucosa might be
deformed by peristalsis or villous motility in vivo
(28,
29). Mechanical forces such as
repetitive deformation are likely cell-type and frequency-specific, as
different cell types respond to different frequencies. Vascular endothelial
cells respond to frequencies of 60–80 cycles/min
(25), whereas intestinal
epithelial cells may actually decrease proliferation in response to
frequencies of 5 cycles/min
(30). We characterized PI3K,
AKT, and GSK phosphorylation with strain, blocked these molecules
pharmacologically or by siRNA, and delineated the specificity of the AKT
effect using isozyme-specific siRNA and transfection of AKT1/2 chimeras. We
also characterized the interaction of this pathway with the activation of ERK
by strain, which has previously been implicated in the mitogenic response
(12). 相似文献
10.
Efrén Ordó?ez Karolien Van Belle Goedele Roos Sandra De Galan Michal Letek Jose A. Gil Lode Wyns Luis M. Mateos Joris Messens 《The Journal of biological chemistry》2009,284(22):15107-15116
We identified the first enzymes that use mycothiol and mycoredoxin in a
thiol/disulfide redox cascade. The enzymes are two arsenate reductases from
Corynebacterium glutamicum (Cg_ArsC1 and Cg_ArsC2), which play a key
role in the defense against arsenate. In vivo knockouts showed that
the genes for Cg_ArsC1 and Cg_ArsC2 and those of the enzymes of the mycothiol
biosynthesis pathway confer arsenate resistance. With steady-state kinetics,
arsenite analysis, and theoretical reactivity analysis, we unraveled the
catalytic mechanism for the reduction of arsenate to arsenite in C.
glutamicum. The active site thiolate in Cg_ArsCs facilitates adduct
formation between arsenate and mycothiol. Mycoredoxin, a redox enzyme for
which the function was never shown before, reduces the thiol-arseno bond and
forms arsenite and a mycothiol-mycoredoxin mixed disulfide. A second molecule
of mycothiol recycles mycoredoxin and forms mycothione that, in its turn, is
reduced by the NADPH-dependent mycothione reductase. Cg_ArsCs show a low
specificity constant of ∼5 m-1 s-1,
typically for a thiol/disulfide cascade with nucleophiles on three different
molecules. With the in vitro reconstitution of this novel electron
transfer pathway, we have paved the way for the study of redox mechanisms in
actinobacteria.The frequent abundance of arsenic in the environment has guided the
evolution of enzymes for the reduction of arsenate
(As(V))4
(1). Arsenate reductases
(ArsCs) are unusual among well studied enzyme classes, because there is not a
single family of evolutionarily related sequences. The structural folds and
mechanisms that they are using are fundamentally different and arose
independently during evolution
(2). Arsenate reductases are
small cytoplasmic redox enzymes that reduce arsenate to arsenite (As(III)) by
the sequential involvement of three different thiolate nucleophiles that
function as a redox cascade. As such, arsenate reductases from different
organisms often work together with the thiol/disulfide mechanism in the
cell.The major and most ubiquitous system for protection against oxidative
stress and to maintain the intracellular thiol homeostasis is the thioredoxin
system that is composed of Trx (thioredoxin) and TrxR (thioredoxin reductase)
(3). In addition to the
thioredoxin system, most living organisms contain low molecular weight thiol
compounds that serve as a buffer to avert disulfide stress. In eukaryotes and
Gram-negative bacteria, the redox level is maintained by redox cycling of
glutathione (GSH) with Grx (glutaredoxin) and glutathione reductase
(4). Gram-positive bacteria,
like Staphylococcus aureus, produce no glutathione, but millimolar
quantities of reduced coenzyme A is the predominant thiol, which is kept
reduced with a NADPH-dependent flavoenzyme, coenzyme A disulfide reductase
(5). Also actinobacteria, like
Corynebacterium glutamicum, produce no GSH, but instead they contain
millimolar concentrations of MSH (mycothiol; chemically
1D-myo-inosityl-2-[N-acetyl-l-cysteinyl]
amido-2-deoxy-α-d-glucopyranoside), a pseudodisaccharide
containing a cysteine moiety as a reactive thiol
(6). Its oxidized form is
mycothione (MSSM). In actinobacteria, MTR (mycothione reductase) is the
NADPH-dependent flavoenzyme that reduces MSSM in order to maintain the
intracellular redox homeostasis to allow the proper functioning of a variety
of biological functions
(7).Arsenate reductases are part of a defense mechanism of the cell against
toxic arsenate. Their genes are most of the time found in an operon together
with arsenite sensing and efflux genes
(8). Based on the mechanism
used to reduce arsenate to arsenite, two distinct ArsC classes can be defined.
The first one is the thioredoxin-coupled ArsC class represented by S.
aureus pI258 ArsC and Bacillus subtilis ArsC
(9–11).
Both enzymes use the structural fold of low molecular weight tyrosine
phosphatase and need Trx to start a second catalytic cycle
(12–14).
The second class is the GSH/glutaredoxin-coupled class represented by
Escherichia coli plasmid R773 ArsC
(15,
16), the eukaryotic Acr2p
reductase from Saccharomyces cerevisiae
(17), and ArsC from
Leishmania major
(18). In this second class,
two different structural folds are found; E. coli R773 ArsC partially
resembles glutaredoxin (19),
whereas the eukaryotic ArsCs have a rhodanese fold like the Cdc25a cell cycle
control phosphatase (20).
Notably, all arsenate reductases have a thiolate nucleophile at the N-terminal
end of an α-helix. The active site of the ArsCs with a phosphatase-like
scaffold is conserved (root mean square deviation of 0.54 Å) with a
catalytically important Arg on position Cys+6.In C. glutamicum, there are four arsC genes located on
different places in the chromosome
(21): one orphan arsC
gene (arsC4) and three arsC genes
(arsC1-arsC1′ and arsC2) present in two
ars operons. We show here that two of the encoded proteins, Cg_ArsC1
and Cg_ArsC2 (with 66% sequence identity) are members of a new third class,
the mycothiol- and mycoredoxin-dependent arsenate reductases. Both the genes
of arsC1 and arsC2, together with the genes for the enzymes
of the mycothiol biosynthesis pathway are involved in arsenate resistance in
C. glutamicum. We have reconstituted in vitro a novel
electron transfer network containing, next to Cg_ArsC1 or Cg_ArsC2, mycothiol,
mycoredoxin, and mycothione reductase. As such, the mechanism for the
reduction of arsenate by C. glutamicum could be unraveled. 相似文献
11.
12.
Metabolism of
d-Glycero-d-Manno-Heptitol,
Volemitol, in Polyanthus. Discovery of a Novel Ketose
Reductase
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Volemitol
(d-glycero-d-manno-heptitol,
α-sedoheptitol) is an unusual seven-carbon sugar alcohol that
fulfills several important physiological functions in certain species
of the genus Primula. Using the horticultural hybrid
polyanthus (Primula × polyantha) as
our model plant, we found that volemitol is the major nonstructural
carbohydrate in leaves of all stages of development, with
concentrations of up to 50 mg/g fresh weight in source leaves (about
25% of the dry weight), followed by sedoheptulose
(d-altro-2-heptulose, 36 mg/g fresh weight),
and sucrose (4 mg/g fresh weight). Volemitol was shown by the
ethylenediaminetetraacetate-exudation technique to be a prominent
phloem-mobile carbohydrate. It accounted for about 24% (mol/mol) of
the phloem sap carbohydrates, surpassed only by sucrose (63%).
Preliminary 14CO2 pulse-chase radiolabeling
experiments showed that volemitol was a major photosynthetic product,
preceded by the structurally related ketose sedoheptulose. Finally, we
present evidence for a novel NADPH-dependent ketose reductase,
tentatively called sedoheptulose reductase, in volemitol-containing
Primula species, and propose it as responsible for the
biosynthesis of volemitol in planta. Using enzyme extracts from
polyanthus leaves, we determined that sedoheptulose reductase has a pH
optimum between 7.0 and 8.0, a very high substrate specificity, and
displays saturable concentration dependence for both sedoheptulose
(apparent Km = 21 mm) and NADPH
(apparent Km = 0.4 mm). Our
results suggest that volemitol is important in certain
Primula species as a photosynthetic product, phloem
translocate, and storage carbohydrate.Alditols (sugar alcohols or acyclic polyols) may be chemically
described as reduction products of aldose or ketose sugars. The most
prevalent plant alditols are the hexitols sorbitol, mannitol, and
galactitol. However, as many as 17 different alditols occur naturally
in higher plants (for review, see Bieleski, 1982; Lewis, 1984; Loescher
and Everard, 1996). The lesser-known alditols are often restricted in
their occurrence but still fulfill important functions in those plants
where they do occur. Volemitol (Fig. (Fig.1)
1)
is a good example of a less common but important alditol. This
seven-carbon sugar alcohol seems to be confined to certain sections of
the genus Primula, so much so that it has been suggested as
a useful chemotaxonomical marker (Kremer, 1978). Very little is known
about the physiology and metabolism of volemitol in primulas, except
that it was an early photosynthetic product in cowslip (Primula
veris) and oxslip (Primula elatior) (Kremer, 1978).
Figure 1Fischer projections of volemitol and its four
structurally related seven-carbon sugars. Nomenclature follows that of
Collins (1987); trivial names are underlined.The physiological roles of alditols are manifold and largely resemble
those of disaccharides and oligosaccharides. They include
photosynthetic assimilation, translocation and storage of carbon, and
reducing power, as well as protection against different types of
stresses (for review, see Bieleski, 1982; Lewis, 1984; Loescher and
Everard, 1996; Stoop et al., 1996). The biosynthetic pathways of the
hexitols sorbitol (glucitol), mannitol, galactitol (dulcitol), and the
pentitol ribitol have been established in higher plants. They generally
use NADPH as a hydrogen donor and aldose phosphate as a hydrogen
acceptor, in concert with the corresponding phosphatases. One exception
might be galactitol, which was suggested to be formed directly from
unphosphorylated Gal (and NADPH) (Negm, 1986). Although all foliar
alditols are thought to be phloem-mobile (Lewis, 1984), this has only
been demonstrated for sorbitol, mannitol, and galactitol (Zimmermann
and Ziegler, 1975; Davis and Loescher, 1990; Moing et al., 1992; Flora
and Madore, 1993).To expand our knowledge of alditol metabolism in higher plants beyond
that of hexitols, we studied the carbohydrate metabolism of polyanthus
(Primula × polyantha). This popular
horticultural hybrid of primrose (Primula
vulgaris), oxlip, and cowslip (Mabberley, 1997) was
chosen because preliminary experiments showed that its volemitol
content is very high, similar to that of the wild-type species, and
because it may be easily grown both outdoors and indoors.We give a general overview on volemitol metabolism in polyanthus with
special emphasis on the role of volemitol in plant development and
phloem transport. We also report on a novel enzyme, a NADPH-dependent
ketose reductase, which forms volemitol by the reduction
of sedoheptulose. 相似文献
13.
14.
The enigmatic, cleptoparasitic bee genera Brachymelecta Linsley and Sinomelecta Baker (Apinae: Melectini) are redescribed, each represented by a single species which has not been reencountered since capture of the type series ca. 1878 and 1900, respectively. Both genera are the only melectines to possess two submarginal cells in the forewing but are otherwise wholly dissimilar. Brachymelecta mucida (Cresson), a species known only from the male holotype collected in “Nevada”, is newly described and figured, including the first account of the hidden sterna and genitalia. Sinomelecta oreina Baker is similarly described and figured based on the holotype male and paratype female, apparently collected from the eastern Tibetan Plateau. Both genera are valid and from the available data do not appear to represent merely autapomorphic forms of Melecta Latreille. Indeed, the terminalia of Sinomelecta oreina are in some respects more similar to those of species of Thyreus Panzer. 相似文献
15.
16.
17.
Interaction of Cryptochrome 1, Phytochrome, and Ion Fluxes in
Blue-Light-Induced Shrinking of Arabidopsis
Hypocotyl
Protoplasts 总被引:6,自引:1,他引:5
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Protoplasts isolated from red-light-adapted Arabidopsis hypocotyls and incubated under red light exhibited rapid and transient shrinking within a period of 20 min in response to a blue-light pulse and following the onset of continuous blue light. Long-persisting shrinkage was also observed during continuous stimulation. Protoplasts from a hy4 mutant and the phytochrome-deficient phyA/phyB double mutant of Arabidopsis showed little response, whereas those from phyA and phyB mutants showed a partial response. It is concluded that the shrinking response itself is mediated by the HY4 gene product, cryptochrome 1, whereas the blue-light responsiveness is strictly controlled by phytochromes A and B, with a greater contribution by phytochrome B. It is shown further that the far-red-absorbing form of phytochrome (Pfr) was not required during or after, but was required before blue-light perception. Furthermore, a component that directly determines the blue-light responsiveness was generated by Pfr after a lag of 15 min over a 15-min period and decayed with similar kinetics after removal of Pfr by far-red light. The anion-channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid prevented the shrinking response. This result, together with those in the literature and the kinetic features of shrinking, suggests that anion channels are activated first, and outward-rectifying cation channels are subsequently activated, resulting in continued net effluxes of Cl− and K+. The postshrinking volume recovery is achieved by K+ and Cl− influxes, with contribution by the proton motive force. External Ca2+ has no role in shrinking and the recovery. The gradual swelling of protoplasts that prevails under background red light is shown to be a phytochrome-mediated response in which phytochrome A contributes more than phytochrome B. 相似文献
18.
19.
Alok De Archana De Chris Papasian Shane Hentges Snigdha Banerjee Inamul Haque Sushanta K. Banerjee 《PloS one》2013,8(8)
Patients with ovarian cancer (OC) may be treated with surgery, chemotherapy
and/or radiation therapy, although none of these strategies are very effective.
Several plant-based natural products/dietary supplements, including extracts
from
Emblica
officinalis
(Amla), have
demonstrated potent anti-neoplastic properties. In this study we determined that
Amla extract (AE) has anti-proliferative effects on OC cells under both
in vitro and in vivo conditions. We also
determined the anti-proliferative effects one of the components of AE,
quercetin, on OC cells under in vitro conditions. AE did not
induce apoptotic cell death, but did significantly increase the expression of
the autophagic proteins beclin1 and LC3B-II under in vitro
conditions. Quercetin also increased the expression of the autophagic proteins
beclin1 and LC3B-II under in vitro conditions. AE also
significantly reduced the expression of several angiogenic genes, including
hypoxia-inducible factor 1α (HIF-1α) in OVCAR3 cells. AE acted synergistically
with cisplatin to reduce cell proliferation and increase expression of the
autophagic proteins beclin1 and LC3B-II under in vitro
conditions. AE also had anti-proliferative effects and induced the expression of
the autophagic proteins beclin1 and LC3B-II in mouse xenograft tumors.
Additionally, AE reduced endothelial cell antigen – CD31 positive blood vessels
and HIF-1α expression in mouse xenograft tumors. Together, these studies
indicate that AE inhibits OC cell growth both in vitro and
in vivo possibly via inhibition of angiogenesis and
activation of autophagy in OC. Thus AE may prove useful as an alternative or
adjunct therapeutic approach in helping to fight OC. 相似文献
20.
Cerebral lateralization is a widespread trait among animals, is often manifested as side biases in behaviour (laterality) and has been suggested to provide fitness benefits. Here we examined the influence of laterality on the organisation of fish schools using rainbowfish (Melanotaenia
spp) as model species. The pattern and strength of laterality for each individual was determined by examining eye preferences whilst examining their reflection in a mirror. Schools of four fish of known laterality were then created and the preferred position for each fish within the school was repeatedly observed in a flume. Fish which showed right eye preferences in the mirror test preferentially adopted a position on the left side of the school. Conversely, fish that showed left eye preferences in the mirror test or where non-lateralised preferentially adopted a position slightly to the right side of the school. However, this general pattern varied depending on the species and sex of the school. Our results strongly implicate individual laterality in the geometry of school formation. 相似文献