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1.
Self-Nonself Recognition Activity Extracted from Self-Sterile Eggs of the Ascidian, Ciona intestinalis 总被引:1,自引:1,他引:0
Kazuo Kawamura Maki Nomura Tomoko Kameda Hiroko Shimamoto Mitsuaki Nakauchi 《Development, growth & differentiation》1991,33(2):139-148
Eggs of the hermaphrodite, self-sterile ascidian, Ciona intestinalis , were washed with acid seawater (pH 3.2), and the washing solution was then adjusted to pH 8.2. This solution was found to inhibit only the binding of non-autologous sperm to the vitelline coat (VC) of eggs, indicating that it contained self-nonself recognition activity. This activity was heat-stable and insensitive to trypsin, but was destroyed by V-8 protease and α-glucosidase. Both the hydrophobic and hydrophilic components of a lyophilized powder of the extract showed allo-recognizing activity. On TLC, the hydrophobic components gave a major spot of glucose (Glc) and a peptide spot(s) containing mainly glutamic acid and/or glutamine (Glx). The glucosyl conjugate was purified by HPLC and shown to block sperm-egg binding to various extents. Individual peptide subfractions had no inhibitory activity, but in combination they showed inhibitory activity. These findings suggest that the acid extract of Ciona eggs contains a Glc-enriched nonspecific inhibitor of sperm-egg binding, which could be the primary effector of self-incompatibility, and Glx-enriched modulators, which serve as acceptors of allo-sperm. The cooperative interactions of these components may be responsible for the diversity of allo-recognition in Ciona gametes. 相似文献
2.
Tae-Young Kim Ding Wang Allen K. Kim Edward Lau Amanda J. Lin David A. Liem Jun Zhang Nobel C. Zong Maggie P. Y. Lam Peipei Ping 《Molecular & cellular proteomics : MCP》2012,11(12):1586-1594
Mitochondrial dysfunction is associated with many human diseases. Mitochondrial damage is exacerbated by inadequate protein quality control and often further contributes to pathogenesis. The maintenance of mitochondrial functions requires a delicate balance of continuous protein synthesis and degradation, i.e. protein turnover. To understand mitochondrial protein dynamics in vivo, we designed a metabolic heavy water (2H2O) labeling strategy customized to examine individual protein turnover in the mitochondria in a systematic fashion. Mice were fed with 2H2O at a minimal level (<5% body water) without physiological impacts. Mitochondrial proteins were analyzed from 9 mice at each of the 13 time points between 0 and 90 days (d) of labeling. A novel multiparameter fitting approach computationally determined the normalized peak areas of peptide mass isotopomers at initial and steady-state time points and permitted the protein half-life to be determined without plateau-level 2H incorporation. We characterized the turnover rates of 458 proteins in mouse cardiac and hepatic mitochondria and found median turnover rates of 0.0402 d−1 and 0.163 d−1, respectively, corresponding to median half-lives of 17.2 d and 4.26 d. Mitochondria in the heart and those in the liver exhibited distinct turnover kinetics, with limited synchronization within functional clusters. We observed considerable interprotein differences in turnover rates in both organs, with half-lives spanning from hours to months (∼60 d). Our proteomics platform demonstrates the first large-scale analysis of mitochondrial protein turnover rates in vivo, with potential applications in translational research.Mitochondrial dysfunctions are observed in disorders such as neurodegeneration, cardiovascular diseases, and aging (1–3). It is postulated that the failure to contain or replenish mitochondrial proteins damaged by reactive oxygen species directly underlies many pathological phenotypes (4). The development of effective treatments for these diseases therefore relies on understanding the molecular basis of protein dynamics. Outstanding questions are how the processes of mitochondrial proteome dynamics are regulated in different systems, and how their perturbations could progress to pathological remodeling of the organelle. Thus far, quantitative proteomics efforts have been predominated by steady-state measurements, which often provide fragmentary snapshots of the proteome that are difficult to comprehend in the context of other cellular events.To further understand mitochondrial dynamics in vivo, we examined the turnover rates of individual heart and liver mitochondrial proteins on a proteome scale. Both the liver and the heart contain large numbers of mitochondria, but cardiac and hepatic mitochondria differ in their protein composition, oxygen consumption, substrate utilization, and disease manifestation. However, these differences are often interpreted only by protein compositions and steady-state abundance, without the consideration of protein kinetics in the temporal dimension. Abnormal protein kinetics may indicate dysfunctions in protein quality control, the accumulation of damaged proteins, misfolding, or other proteinopathies. Protein dynamics itself is an important intrinsic property of the proteome, the disruption of which could be causal of cellular etiologies.At minimum, a kinetic definition of the proteome requires knowledge of the rate at which individual proteins are being replaced. Isotope tracers are particularly useful for tracking such continual renewal of the proteome in living systems, because they allow differentiation between preexisting and newly synthesized proteins (5). Among the available stable isotope precursors, heavy water (2H2O) labeling offers several advantages with respect to safety, labeling kinetics, and cost (6, 7). First, 2H2O administration to animals and humans at low enrichment levels is safe for months or even years (8). Second, maintaining constant 2H enrichment levels in body water following the initial intake of 2H2O is easily achieved, because administrated 2H2O rapidly equilibrates over all tissues but decays slowly (9, 10). Third, 2H2O labeling is more cost effective than other stable isotope labeling methods. Importantly, 2H2O intake induces universal 2H incorporation into biomolecules. Systematic insights into protein turnover in vivo could therefore be correlated to that of nucleic acids, carbohydrates, or lipids, enabling broad applications for this technology in studying mammalian systems, including humans.A variety of methodologies have been developed to analyze the extent of 2H incorporation in proteins following 2H2O labeling, including GC-MS measurements of hydrolyzed target proteins (11–14) and peptide analysis in MALDI-TOF MS (15) and LC-MS (16, 17). More recently, Price et al. described an approach for measuring protein turnover by calculating the theoretical number of 2H-labeling sites on a peptide sequence (18) and reported the turnover rates of ∼100 human plasma proteins. Here we describe another novel strategy to determine protein turnover rates on a proteomic scale using 2H2O labeling. By computing the parameters needed to deduce fractional protein synthesis using software we developed, we were able to obtain protein half-life data without relying on the asymptotic isotopic abundance of peptide ions. Our approach also has the unique benefit of automating all steps of isotopomer quantification and postcollection data analysis, and it does not require knowledge of the exact precursor enrichment or labeling sites of peptides. We observed diverse kinetics from 458 liver and heart mitochondrial proteins that inform essential characteristics of mitochondrial dynamics and intragenomic differences between the two organs. 相似文献
3.
Ryoko Hashimoto Birger Voigt Yuji Ishimaru Ryoji Hokao Shigeru Chiba Tadao Serikawa Masashi Sasa Takashi Kuramoto 《Experimental Animals》2013,62(3):181-187
Amygdala kindling is useful for modeling human epilepsy development. It has been known
that genetic factors are involved in the development of amygdala kindling. The purpose of
this study was to identify the loci that are responsible for the development of amygdala
kindling. To achieve this, rat strains from a LEXF/FXLE recombinant inbred (RI) strain
panel were used. The phenotypes of amygdala kindling-related parameters for seven RI
strains and parental LE/Stm and F344/Stm strains were determined. They included the
afterdischarge threshold (ADT), the afterdischarge duration (ADD), and the kindling rate,
an incidence of development of kindling. Quantitative trait loci (QTL) analysis was
performed to identify linkage relationships between these phenotypes and 1,033 SNP
markers. Although no significant differences in pre-kindling ADT and ADD were observed, a
significant difference in the kindling rate was found for the LEXF/FXLE RI strain. Two
QTLs for the amygdala kindling rate (Agkr1 and Agkr2)
were identified on rat chromosome 2. These findings clearly prove the existence of genetic
influences that are involved in kindling development and suggest that substantial genetic
components contribute to the progression of partial seizures into generalized
seizures. 相似文献
4.
Cloning of Nicotianamine Synthase Genes, Novel Genes Involved in
the Biosynthesis of Phytosiderophores 总被引:15,自引:0,他引:15
Kyoko Higuchi Kazuya Suzuki Hiromi Nakanishi Hirotaka Yamaguchi Naoko-Kishi Nishizawa Satoshi Mori 《Plant physiology》1999,119(2):471-480
Nicotianamine synthase (NAS), the key enzyme in the biosynthetic pathway for the mugineic acid family of phytosiderophores, catalyzes the trimerization of S-adenosylmethionine to form one molecule of nicotianamine. We purified NAS protein and isolated the genes nas1, nas2, nas3, nas4, nas5-1, nas5-2, and nas6, which encode NAS and NAS-like proteins from Fe-deficient barley (Hordeum vulgare L. cv Ehimehadaka no. 1) roots. Escherichia coli expressing nas1 showed NAS activity, confirming that this gene encodes a functional NAS. Expression of nas genes as determined by northern-blot analysis was induced by Fe deficiency and was root specific. The NAS genes form a multigene family in the barley and rice genomes. 相似文献
5.
The Properties of the Oviducal Pars Recta Protease which Mediates Gamete Interaction by Affecting the Vitelline Coat of a Toad Egg 总被引:2,自引:2,他引:0
SDS-PAGE analyses of the vitelline coats (VCs) of coelomic eggs (CEVC) and uterine eggs (UEVC) of Bufo japonicus revealed that the UEVC lacks the 40K–52K molecular weight components present in the CEVC; this is concomitant with the increased stainability of a 39K component and the appearance of a 36K component. These macromolecular alterations, accompanied by the acquisition of egg fertilizability, were induced when coelomic eggs were treated with the contents of secretory granules obtained from the oviducal pars recta (PRG). Gel-filtration of PRG in combination with hydrolytic assays employing either fluorescamine-labeled CEVC or a variety of synthetic substrates showed that the CEVC to UEVC alterations are ascribable to the action of a protease hydrolyzing specifically peptidyl-Arg-MCAs in a highly Ca2+ -dependent way. This enzyme, which has an optimal pH of 8.0–8.2, is inhibited by soybean trypsin inhibitor and leupeptin, as well as by such serine protease inhibitors as DFP and p-APMSF. On the basis of a SDS-PAGE analysis, its molecular weight is estimated to be 66K. Treatment of coelomic eggs with the partially purified PR protease did not render the eggs fertilizable, although CEVC to UEVC macromolecular alterations were effected. We conclude that the action of this oviducal protease in partially hydrolyzing the VC is a prerequisite but insufficient in itself to render the coelomic eggs fully accessible to a fertilizing sperm. 相似文献
6.
7.
Evidence for a Cytoskeleton-Associated Binding Site Involved in
Prolamine mRNA Localization to the Protein Bodies in Rice Endosperm
Tissue 总被引:4,自引:0,他引:4 下载免费PDF全文
Previous studies have demonstrated that the mRNAs encoding the prolamine and glutelin storage proteins are localized to morphologically distinct membranes of the endoplasmic reticulum (ER) complex in developing rice (Oryza sativa L.) endosperm cells. To gain insight about this mRNA localization process, we investigated the association of prolamine polysomes on the ER that delimit the prolamine protein bodies (PBs). The bulk of the prolamine polysomes were resistant to extraction by 1% Triton X-100 either alone or together with puromycin, which suggests that these translation complexes are anchored to the PB surface through a second binding site in addition to the well-characterized ribosome-binding site of the ER-localized protein translocation complex. Suppression of translation initiation shows that these polysomes are bound through the mRNA, as shown by the simultaneous increase in the amounts of ribosome-free prolamine mRNAs and decrease in prolamine polysome content associated with the membrane-stripped PB fraction. The prolamine polysome-binding activity is likely to be associated with the cytoskeleton, based on the association of actin and tubulin with the prolamine polysomes and PBs after sucrose-density centrifugation. 相似文献
8.
Estimating the Excess Investment in
Ribulose-1,5-Bisphosphate
Carboxylase/Oxygenase in
Leaves of Spring Wheat Grown under Elevated
CO2 下载免费PDF全文
Julian C. Theobald Rowan A.C. Mitchell Martin A.J. Parry David W. Lawlor 《Plant physiology》1998,118(3):945-955
Wheat (Triticum aestivum L.) was grown under CO2 partial pressures of 36 and 70 Pa with two N-application regimes. Responses of photosynthesis to varying CO2 partial pressure were fitted to estimate the maximal carboxylation rate and the nonphotorespiratory respiration rate in flag and preceding leaves. The maximal carboxylation rate was proportional to ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) content, and the light-saturated photosynthetic rate at 70 Pa CO2 was proportional to the thylakoid ATP-synthase content. Potential photosynthetic rates at 70 Pa CO2 were calculated and compared with the observed values to estimate excess investment in Rubisco. The excess was greater in leaves grown with high N application than in those grown with low N application and declined as the leaves senesced. The fraction of Rubisco that was estimated to be in excess was strongly dependent on leaf N content, increasing from approximately 5% in leaves with 1 g N m−2 to approximately 40% in leaves with 2 g N m−2. Growth at elevated CO2 usually decreased the excess somewhat but only as a consequence of a general reduction in leaf N, since relationships between the amount of components and N content were unaffected by CO2. We conclude that there is scope for improving the N-use efficiency of C3 crop species under elevated CO2 conditions. 相似文献
9.
Don C. Forester Melissa Cameron James D. Forester 《Ethology : formerly Zeitschrift fur Tierpsychologie》2008,114(10):965-976
We conducted a comparative investigation of nest relocation and egg recognition by four species of streamside salamanders indigenous to eastern North America: Seepage Salamander (Desmognathus aeneus), Santeetlah Salamander (Desmognathus santeetlah), Ocoee Salamander (Desmognathus ocoee), and Northern Dusky Salamander (Desmognathus fuscus). Females of all four species were able to relocate their nest sites following displacement of 1 m. Upon return to a nest site following natural displacement, females must be able to recognize their eggs and, in some instances, choose between their own clutch and the unattended clutch of a conspecific. In two‐choice behavioral tests, female salamanders of all four species moved randomly within the test chamber in the absence of eggs, but preferred their own eggs to a filter paper blank. One species, D. fuscus, exhibited a similar attraction to conspecific eggs suggesting that the presence of eggs, regardless of their origin, may stimulate maternal care in physiologically primed females. We found that egg discrimination is not as infallible as previously reported. All four species spent more time with their own eggs than they did with the eggs of a conspecific female; however, this trend was significant for D. ocoee only. Interspecific variation in egg discrimination is attributed to differential selection associated with the life history of individual species. 相似文献
10.
Maika Deffieu Ingrid Bhatia-Ki??ová Bénédicte Salin Anne Galinier Stéphen Manon Nadine Camougrand 《The Journal of biological chemistry》2009,284(22):14828-14837
The antioxidant N-acetyl-l-cysteine prevented the
autophagy-dependent delivery of mitochondria to the vacuoles, as examined by
fluorescence microscopy of mitochondria-targeted green fluorescent protein,
transmission electron microscopy, and Western blot analysis of mitochondrial
proteins. The effect of N-acetyl-l-cysteine was specific
to mitochondrial autophagy (mitophagy). Indeed, autophagy-dependent activation
of alkaline phosphatase and the presence of hallmarks of non-selective
microautophagy were not altered by N-acetyl-l-cysteine.
The effect of N-acetyl-l-cysteine was not related to its
scavenging properties, but rather to its fueling effect of the glutathione
pool. As a matter of fact, the decrease of the glutathione pool induced by
chemical or genetical manipulation did stimulate mitophagy but not general
autophagy. Conversely, the addition of a cell-permeable form of glutathione
inhibited mitophagy. Inhibition of glutathione synthesis had no effect in the
strain Δuth1, which is deficient in selective mitochondrial
degradation. These data show that mitophagy can be regulated independently of
general autophagy, and that its implementation may depend on the cellular
redox status.Autophagy is a major pathway for the lysosomal/vacuolar delivery of
long-lived proteins and organelles, where they are degraded and recycled.
Autophagy plays a crucial role in differentiation and cellular response to
stress and is conserved in eukaryotic cells from yeast to mammals
(1,
2). The main form of autophagy,
macroautophagy, involves the non-selective sequestration of large portions of
the cytoplasm into double-membrane structures termed autophagosomes, and their
delivery to the vacuole/lysosome for degradation. Another process,
microautophagy, involves the direct sequestration of parts of the cytoplasm by
vacuole/lysosomes. The two processes coexist in yeast cells but their extent
may depend on different factors including metabolic state: for example, we
have observed that nitrogen-starved lactate-grown yeast cells develop
microautophagy, whereas nitrogen-starved glucose-grown cells preferentially
develop macroautophagy (3).Both macroautophagy and microautophagy are essentially non-selective, in
the way that autophagosomes and vacuole invaginations do not appear to
discriminate the sequestered material. However, selective forms of autophagy
have been observed (4) that
target namely peroxisomes (5,
6), chromatin
(7,
8), endoplasmic reticulum
(9), ribosomes
(10), and mitochondria
(3,
11–13).
Although non-selective autophagy plays an essential role in survival by
nitrogen starvation, by providing amino acids to the cell, selective autophagy
is more likely to have a function in the maintenance of cellular structures,
both under normal conditions as a “housecleaning” process, and
under stress conditions by eliminating altered organelles and macromolecular
structures
(14–16).
Selective autophagy targeting mitochondria, termed mitophagy, may be
particularly relevant to stress conditions. The mitochondrial respiratory
chain is both the main site and target of
ROS4 production
(17). Consequently, the
maintenance of a pool of healthy mitochondria is a crucial challenge for the
cells. The progressive accumulation of altered mitochondria
(18) caused by the loss of
efficiency of the maintenance process (degradation/biogenesis de
novo) is often considered as a major cause of cellular aging
(19–23).
In mammalian cells, autophagic removal of mitochondria has been shown to be
triggered following induction/blockade of apoptosis
(23), suggesting that
autophagy of mitochondria was required for cell survival following
mitochondria injury (14).
Consistent with this idea, a direct alteration of mitochondrial permeability
properties has been shown to induce mitochondrial autophagy
(13,
24,
25). Furthermore, inactivation
of catalase induced the autophagic elimination of altered mitochondria
(26). In the yeast
Saccharomyces cerevisiae, the alteration of
F0F1-ATPase biogenesis in a conditional mutant has been
shown to trigger autophagy
(27). Alterations of
mitochondrial ion homeostasis caused by the inactivation of the
K+/H+ exchanger was shown to cause both autophagy and
mitophagy (28). We have
reported that treatment of cells with rapamycin induced early ROS production
and mitochondrial lipid oxidation that could be inhibited by the hydrophobic
antioxidant resveratrol (29).
Furthermore, resveratrol treatment impaired autophagic degradation of both
cytosolic and mitochondrial proteins and delayed rapamycin-induced cell death,
suggesting that mitochondrial oxidation events may play a crucial role in the
regulation of autophagy. This existence of regulation of autophagy by ROS has
received molecular support in HeLa cells
(30): these authors showed
that starvation stimulated ROS production, namely H2O2,
which was essential for autophagy. Furthermore, they identified the cysteine
protease hsAtg4 as a direct target for oxidation by
H2O2. This provided a possible connection between the
mitochondrial status and regulation of autophagy.Investigations of mitochondrial autophagy in nitrogen-starved lactate-grown
yeast cells have established the existence of two distinct processes: the
first one occurring very early, is selective for mitochondria and is dependent
on the presence of the mitochondrial protein Uth1p; the second one occurring
later, is not selective for mitochondria, is not dependent on Uth1p, and is a
form of bulk microautophagy
(3). The absence of the
selective process in the Δuth1 mutant strongly delays and
decreases mitochondrial protein degradation
(3,
12). The putative protein
phosphatase Aup1p has been also shown to be essential in inducing mitophagy
(31). Additionally several Atg
proteins were shown to be involved in vacuolar sequestration of mitochondrial
GFP (3,
12,
32,
33). Recently, the protein
Atg11p, which had been already identified as an essential protein for
selective autophagy has also been reported as being essential for mitophagy
(33).The question remains as to identify of the signals that trigger selective
mitophagy. It is particularly intriguing that selective mitophagy is activated
very early after the shift to a nitrogen-deprived medium
(3). Furthermore, selective
mitophagy is very active on lactate-grown cells (with fully differentiated
mitochondria) but is nearly absent in glucose-grown cells
(3). In the present paper, we
investigated the relationships between the redox status of the cells and
selective mitophagy, namely by manipulating glutathione. Our results support
the view that redox imbalance is a trigger for the selective elimination of
mitochondria. 相似文献
11.
12.
13.
Jianzhong Liu Shunqing Wang Ping Zhang Nasser Said-Al-Naief Suzanne M. Michalek Xu Feng 《The Journal of biological chemistry》2009,284(18):12512-12523
Lipopolysaccharide (LPS), a common bacteria-derived product, has long been
recognized as a key factor implicated in periodontal bone loss. However, the
precise cellular and molecular mechanisms by which LPS induces bone loss still
remains controversial. Here, we show that LPS inhibited osteoclastogenesis
from freshly isolated osteoclast precursors but stimulated osteoclast
formation from those pretreated with RANKL in vitro in tissue culture
dishes, bone slices, and a co-culture system containing osteoblasts,
indicating that RANKL-mediated lineage commitment is a prerequisite for
LPS-induced osteoclastogenesis. Moreover, the RANKL-mediated lineage
commitment is long term, irreversible, and TLR4-dependent. LPS exerts the dual
function primarily by modulating the expression of NFATc1, a master regulator
of osteoclastogenesis, in that it abolished RANKL-induced NFATc1 expression in
freshly isolated osteoclast precursors but stimulated its expression in
RANKL-pretreated cells. In addition, LPS prolonged osteoclast survival by
activating the Akt, NF-κB, and ERK pathways. Our current work has not
only unambiguously defined the role of LPS in osteoclastogenesis but also has
elucidated the molecular mechanism underlying its complex functions in
osteoclast formation and survival, thus laying a foundation for future
delineation of the precise mechanism of periodontal bone loss.LPS,2 a
common bacteria-derived product, has long been recognized as a key factor
implicated in the development of chronic periodontitis. LPS plays an important
role in periodontitis by initiating a local host response in gingival tissues
that involves recruitment of inflammatory cells, production of prostanoids and
cytokines, elaboration of lytic enzymes and activation of osteoclast formation
and function to induce bone loss
(1-3).Osteoclasts, the body''s sole bone-resorbing cells, are multinucleated giant
cells that differentiate from cells of hematopoietic lineage upon stimulation
by two critical factors: the macrophage/monocyte colony-forming factor (M-CSF)
and the receptor activator of NF-κB ligand (RANKL)
(4-6).
RANKL exerts its effects on osteoclast formation and function by binding to
its receptor, RANK (receptor activator of NF-κB) expressed on osteoclast
precursors and mature osteoclasts
(7-9).
RANKL also has a decoy receptor, osteoprotegerin, which inhibits RANKL action
by competing with RANK for binding RANKL
(10,
11).RANK is a member of the tumor necrosis factor receptor (TNFR) family
(12). Members of the TNFR
family lack intrinsic enzymatic activity, and hence they transduce
intracellular signals by recruiting various adaptor proteins including TNF
receptor-associated factors (TRAFs) through specific motifs in the cytoplasmic
domain (13,
14). It has been established
that RANK contains three functional TRAF-binding sites
(369PFQEP373, 559PVQEET564, and
604PVQEQG609) that, redundantly, play a role in
osteoclast formation and function
(15,
16). Collectively, through
these functional TRAF-binding motifs, RANK activates six major signaling
pathways, NF-κB, JNK, ERK, p38, NFATc1, and Akt, which play important
roles in osteoclast formation, function, and/or survival
(15,
17-19).
In particular, NFATc1 has been established as a master regulator of osteoclast
differentiation
(20-22).The involvement of osteoclasts in the pathogenesis of periodontal bone loss
is supported by observations that osteoclasts are physically present and
functionally involved in bone resorption in periodontal tissues
(23-27).
RANKL and RANK knockout mice develop osteopetrosis and show failure in tooth
eruption due to a lack of osteoclasts
(24,
25,
28). Moreover,
op/op mice, in which a mutation in the coding region of the
M-CSF gene generates a stop codon that leads to premature termination of
translation of M-CSF mRNA, also show osteopetrosis and failure in tooth
eruption due to a defect in osteoclast development
(26,
27).Whereas the role of osteoclasts in periodontal disease associated alveolar
bone destruction has been well established, the precise role of LPS in
osteoclastogenesis still remains controversial. The vast majority of the
previous studies demonstrated that LPS stimulates osteoclastogenesis. This is
consistent with the role that LPS, a well recognized pathogenic factor in
periodontitis, presumably plays in periodontal bone loss
(29-33).
However, two previous studies demonstrated, surprisingly, that LPS plays
bifunctional roles in osteoclastogenesis in that although it inhibits
osteoclast formation from normal osteoclast precursors, it reverses to promote
osteoclastogenesis from osteoclast precursors pretreated with RANKL
(34,
35). Given that this finding
is inconsistent with the presumed role of LPS as a pathogenic factor in
periodontal bone loss and lacks careful and further validation, the prevalent
view is still that LPS stimulates osteoclastogenesis
(1-3).
Importantly, if LPS indeed has a dual function in osteoclastogenesis, the
molecular mechanism by which LPS exerts a dual effect on osteoclastogenesis
need to be further elucidated.In the present work, using various in vitro assays, we have
demonstrated independently that LPS inhibits osteoclastogenesis from normal
osteoclast precursors but promotes the development of osteoclasts from
RANKL-pretreated cells in tissue culture dishes and bone slices in single-cell
and co-culture settings, confirming the two previous observations that LPS
play a bifunctional role in osteoclastogenesis
(34,
35). Moreover, we have further
shown that the RANKL-mediated lineage commitment is long term and irreversible
in LPS-mediated osteoclastogenesis. More importantly, we have revealed that
LPS inhibits osteoclastogenesis by suppressing NFATc1 expression and JNK
activation while it prolongs osteoclast survival by activating the Akt,
NF-κB, and ERK pathways. These studies have not only unambiguously and
precisely defined the role of LPS in osteoclastogenesis but, more importantly,
may also lead to a paradigm shift in future investigation of the molecular
mechanism of periodontal bone loss. 相似文献
14.
Cecilia Tamborindeguy Michael S. Bereman Stacy DeBlasio David Igwe Dawn M. Smith Frank White Michael J. MacCoss Stewart M. Gray Michelle Cilia 《PloS one》2013,8(8)
Yellow dwarf viruses cause the most economically important virus diseases of cereal crops worldwide and are transmitted by aphid vectors. The identification of aphid genes and proteins mediating virus transmission is critical to develop agriculturally sustainable virus management practices and to understand viral strategies for circulative movement in all insect vectors. Two cyclophilin B proteins, S28 and S29, were identified previously in populations of
Schizaphisgraminum
that differed in their ability to transmit the RPV strain of Cereal yellow dwarf virus (CYDV-RPV). The presence of S29 was correlated with F2 genotypes that were efficient virus transmitters. The present study revealed the two proteins were isoforms, and a single amino acid change distinguished S28 and S29. The distribution of the two alleles was determined in 12 F2 genotypes segregating for CYDV-RPV transmission capacity and in 11 genetically independent, field-collected
S
. graminum
biotypes. Transmission efficiency for CYDV-RPV was determined in all genotypes and biotypes. The S29 isoform was present in all genotypes or biotypes that efficiently transmit CYDV-RPV and more specifically in genotypes that efficiently transport virus across the hindgut. We confirmed a direct interaction between CYDV-RPV and both S28 and S29 using purified virus and bacterially expressed, his-tagged S28 and S29 proteins. Importantly, S29 failed to interact with a closely related virus that is transported across the aphid midgut. We tested for in vivo interactions using an aphid-virus co-immunoprecipitation strategy coupled with a bottom-up LC-MS/MS analysis using a Q Exactive mass spectrometer. This analysis enabled us to identify a third cyclophilin protein, cyclophilin A, interacting directly or in complex with purified CYDV-RPV. Taken together, these data provide evidence that both cyclophilin A and B interact with CYDV-RPV, and these interactions may be important but not sufficient to mediate virus transport from the hindgut lumen into the hemocoel. 相似文献
15.
16.
Amit Mishra Swetha K. Godavarthi Megha Maheshwari Anand Goswami Nihar Ranjan Jana 《The Journal of biological chemistry》2009,284(16):10537-10545
17.
In-feed Medication has been used for a long time to prevent coccidiosis, a worldwide
protozoal disease in rabbits. Florfenicol (FFC) has been widely used in veterinary clinics
for bacterial diseases treatment. Therefore, the use of combinations of coccidiostats with
FFC in rabbits is common. In the present study, we aimed to evaluate the effect of three
coccidiostats, sulfaquinoxaline (SUL), robenidine (ROB), and toltrazuril (TOL), as feed
additives on the pharmacokinetic profile of FFC in rabbits. The disposition kinetics of
FFC in rabbits were investigated after a single intravenous injection (25 mg/kg) in
rabbits fed anticoccidial-free diets or feeds containing SUL (250 ppm), ROB (66 ppm), or
TOL (2 ppm), respectively, for 20 days. Plasma FFC concentrations were determined by the
high performance liquid chromatography (HPLC) method. The pharmacokinetic parameters of
FFC were analyzed using a non-compartmental analysis based on the statistical moment
theory. The results demonstrated that ROB feeding resulted in an obvious decrease in
plasma FFC level as compared with anticoccidial-free feeding. The terminal elimination
half-life (t1/2z), area under the concentration–time curve
(AUC), area under the first moment curve (AUMC), and
mean residence time (MRT) significantly decreased, whereas the
elimination rate constant (λz) and total body clearance
(CLz) obviously increased in rabbits pretreated with ROB.
However, we did not find that SUL or TOL feeding had any effect on the pharmacokinetic
profile of FFC. Our findings suggested that more attention should be paid to the use of
FFC in rabbits supplemented with ROB. 相似文献
18.
19.
20.
The histopathogenesis of the foliar galls induced by Nothanguina phyllobia Thorne in Solanum elaeagnilolium Cav. was examined via serial sections prepared from plant shoots at 11 time intervals (0.5-30 days) following inoculation. Nematodes infected the blades and petioles of young leaves surrounding the shoot apex. Hypertrophy and hyperplasia of the palisade, pith, cortical, and vascular parenchyma resulted in the formation of confluent leaf, petiole, and stem galls up to 25 cm³ in volume. Externally, leaf galls were irregular, light-green, convoluted spheroid bulges distending the abaxial surface. Mature galls contained a cavity lined with parenchymogenous nutritive tissue comprising intercellular spaces and actively dividing hypertrophied cells. These cells contained granular cytoplasm, hypertrophied nuclei, and brightly stained large nucleoli. Vascular tissues were not discernibly affected during the early stages of gall development. As gall development progressed, however, vascular elements were often displaced and disoriented. The histopathology of this nematode indicates that N. phyllobia is a highly specialized parasite and, for that reason, is suitable as a biological control agent. 相似文献