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1.
《生命科学研究》2017,(6):534-541
少突胶质细胞(oligodendrocytes,OLs)在脊椎动物中枢神经系统(central nervous system,CNS)中负责形成包裹神经元轴突的髓鞘,保证神经冲动沿轴突的快速传导,并为其提供营养支持。OLs发育异常及损伤会导致严重的神经系统疾病,比如脑白质营养不良(leukodystrophy)、多发性硬化症(multiple sclerosis,MS)等。少突胶质细胞前体细胞(oligodendrocyte progenitor cells,OPCs)在胚胎期由神经前体细胞(neural progenitor cells,NPCs)产生,该过程受到一系列细胞内外因素的调控,对这一问题的研究也是神经系统研究的重要内容。现主要基于遗传学结果,简述关于OPCs产生的调控机制的最新研究进展。 相似文献
2.
少突胶质细胞(oligodendrocytes, OLs)是中枢神经系统(central nervous system, CNS)中主要的成髓鞘细胞,其功能障碍会引发一系列的神经性疾病,例如:多发性硬化症(multiple sclerosis,MS)和脑白质营养不良。少突胶质细胞祖细胞(oligodendrocyte precursor cells, OPCs)的移植是治疗髓鞘相关疾病的一种潜在方法。在脑损伤后, OPCs可向OLs方向分化并对损伤部位的轴突进行髓鞘化,但是, OPCs在大脑中仅占5%~8%,这种髓鞘修复作用十分有限。通过体外重编程技术生成诱导性少突胶质细胞祖细胞(induced oligodendrocyte precursor cells, iOPCs)的策略可为髓鞘损伤疾病的治疗提供大量的细胞资源。但是该方法仍存在一系列亟待解决的问题,包括i OPCs生成效率较低、体外培养周期较长等。因此,该文从限定性转录因子、miRNA以及小分子物质等方面阐述了iOPCs的生成方法,并分析了iOPCs的现存问题和应用前景,旨在为其在疾病模型构建、药物开发和再生医学等方面的应用提供理论和技术参考。 相似文献
3.
下丘脑正中隆起(mdian eminence,ME)是神经元和少突胶质细胞的可能生态位,营养因素可能通过诱导ME区细胞变化而调控下丘脑功能。为了确定生理条件下休眠的下丘脑干细胞是否存在饮食诱导的可塑性,本研究使用正常饲料、高脂饮食和生酮饮食(一种低碳水、高脂肪的饮食)等不同喂养方式,比较了不同饮食条件下小鼠ME区伸展细胞(tanycytes,TCs)和少突胶质细胞前体细胞(oligodendrocyte precursor cells,OPCs)的增殖情况,首次发现生酮饮食可诱导促进ME区OPCs增殖,阻断脂肪酸氧化通路可抑制生酮饮食诱导的OPCs增殖。本研究初步揭示了饮食诱导对ME区OPCs的影响,为进一步研究ME区OPCs的功能提供了启示。 相似文献
4.
5.
《中国科学:生命科学》2016,(11)
少突胶质细胞(OLs)有望用于治疗多发性硬化和先天性脑瘫等脱髓鞘疾病.近年来,一些研究者利用人的胚胎干细胞和神经干细胞作为起始细胞来获得少突胶质细胞前体细胞(OPCs).然而,神经干细胞的应用受到其来源的限制;现有的将胚胎干细胞分化为OPCs的方法耗时较长.因此,本研究探讨了一种通过在人诱导多能干细胞中过表达两个转录因子(Sox10和Olig2),从而有效获得OPCs的方法.通过这种方法,可以在14天内获得PDGFRα阳性的OPCs,并在56天内获得O4阳性的OPCs.获得的OPCs在和大鼠(Rattusnorvegicus)皮质神经元共培养时能分化为成熟的少突胶质细胞并包裹轴突形成髓鞘.该研究结果在自体细胞移植领域中具有一定的应用潜力. 相似文献
6.
神经干细胞向少突胶质前体细胞的定向分化诱导 总被引:5,自引:0,他引:5
本研究采用神经胶质瘤细胞株(B104 neuroblatoma cells,B104 cells)培养上清(B104CM)和碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF),将冷冻复苏的大鼠胚胎脊髓神经干细胞(neural stem cells,NSCs)定向诱导为少突胶质前体细胞(oligodendrocyte precusor cells,OPCs)。形态学和免疫组化的结果显示,诱导后95%以上的细胞具有双极或多极突起的典型OPCs形态,并表达A285和血小板源生长因子受体-α(platelet derived growth factor receptor-α,PDGFR-α等0PCs标志,所有PDGFR-α阳性的OPCs均不表达β-Tublin Ⅲ,其中仅少量细胞表达胶质原纤维酸性蛋白(glia fibrillary acidic protein,GFAP)。在B104CM和bFGF共存的培养条件下,悬浮培养的OPCs可大量增殖形成少突胶质细胞球,该细胞球可通过传代继续扩增,且扩增的OPCs仍能维持其特有的形态和自我增殖的特性。撤去bFGF和B104CM后,OPCs能进一步分化为成熟的少突胶质细胞(oligodendrocytes,OLs)或Ⅱ型星形胶质细胞。实验表明,诱导NSCs产生的OPCs在形态、增殖以及分化格局等方面均与已报道的存在于胚胎脑区的O-2A前体细胞相类似。该培养系统可为实验性细胞移植的研究提供丰富的细胞来源。 相似文献
7.
8.
中枢神经系统轴突再生抑制蛋白 总被引:1,自引:0,他引:1
中枢神经系统 (CNS)轴突再生的主要障碍之一是存在抑制再生的蛋白 ,迄今 ,已在少突胶质细胞 /髓鞘中相继发现至少三个重要的轴突再生抑制蛋白 ,即髓鞘相关糖蛋白 (MAG)、Nogo A和少突胶质细胞 /髓鞘糖蛋白 (OMgp)。最近的研究又证实 ,这三个不同的抑制成分可能主要通过与一个共同的受体Nogo6 6受体 (NgR)结合而发挥作用。这些研究成果扩充了对CNS损伤后轴突再生障碍的理解 ,也为探讨CNS损伤的治疗新策略提供了新的思路。 相似文献
9.
10.
目的观察ROCK特异性抑制剂Y27632对缺氧损伤(Oxygen-glucose deprivation,OGD)后少突胶质前体细胞分化的影响。方法培养SD大鼠大脑皮层少突胶质前体细胞,实验分为对照组、对照+Y27632组、OGD组、OGD+Y27632组四组;对细胞进行OGD处理2h,取4d后时间点,进行免疫荧光组化染色和Western blot实验,检测细胞A2B5、NG2、O4及MBP蛋白表达情况。结果与对照组相比,OGD组表达少突胶质细胞特异性蛋白MBP量明显增多(P0.01);OGD+Y27632组比单纯OGD组表达少突胶质细胞特异性蛋白MBP的量显著增加(P0.01)。结论 OGD损伤可促进OPCs的分化,Y27632特异性抑制ROCK可以进一步促进OGD损伤后OPCs的分化,提示ROCK信号通路在缺氧诱导OPCs分化的过程中有重要的调控作用。 相似文献
11.
Julia F. Morton 《Economic botany》1991,45(3):318-333
The horseradish tree (Moringa pterygosperma,) is being introduced into drought-ridden lands to augment the local food and
fodder supply. The tree grows up to 5 m per year. The foliage is high in calcium and has half the oxalates of amaranth. Seeds
yield edible oil and the seed meal is used as fertilizer and as a coagulant to clarify turbid water. The philanthropic center,
ECHO (Educational Concerns for Hunger Organization), North Fort Myers, Florida, receives many requests for seeds. A missionary
in Mali wrote: “The seeds you sent arrived during the worst year of 14 years of dry weather. Only the moringa survived, and
they have flourished. ”Another seed shipment resulted, after harvesting a crop, in 25 000 trees being planted by university
students and faculty, around laborers’ houses in Maranhao, Brazil. The tree is not limited to tropical lowlands, but thrives
at elevations of 800-1200 m in protected mountain areas of southern Mexico. The long-range effects of ingesting various parts
of the tree as food or folkmedicine need study. Attention should be given to horticultural improvement, perhaps through hybridization
with one or more related species now being compared with M. pterygosperma in India and Africa.
ХРеНовое дерево, Moringa pterygosperma F. Gaertn. (Moringaceae), Дар сыхим землям. Хреновое дерево, Moringa pterygosperma,
вводится в бездождивые землии чтоб умножить местное снабжение пищи и корма. Дерево растет до 5 метров в год. Листья содержат
много кальцию и половину щавелев по сравнени#x044E; с амарантом. Семя дают съедобное масло и семеная мука употребляется как
одобрение и как коагулант для очищение мутной воды. Филантропический цэнтэр ECHO (Educational Concern for Hunger Organization,
North Fort Myers, Florida) полужает мното просьб чтоб получить семя. Один миссионер из Мали писал “Семя которые вы послали,
прибыли в самый сухой год за 14 лет сухой погоды. Только моринга пережила и цвела. Другая отправка семен была совершена после
получения урожая и 25000 деревьев были посажены студентами и учителями около домов рабочих в Маранхау, Брразилия.
Это дерево не ограаничевается тропическим климатом и преуспевает на уровне 800 до 1200 метров в защищенных горных местах южной
Мексики. 相似文献
12.
Anna Tsing Shiho Satsuka for the Matsutake Worlds Research Group 《Economic botany》2008,62(3):244-253
Diverging Understandings of Forest Management in Matsutake Science. As high-value gourmet mushrooms, the matsutake complex of the genus Tricholoma has been the subject of extensive research. This article reviews two trajectories of matsutake research, showing how distinctive
regional nodes may develop within a cosmopolitan modern science. The global center of matsutake research is in Japan, where
problems of artificial cultivation and the “orchard-style” enhancement of production under forest conditions stimulate basic
research. U.S. Pacific Northwest research forms a contrasting regional node, with a focus on sustainable yields in the context
of timber production. Regional differences in research design and results point to the importance of distinctive scientific
legacies, in this case formed in relation to divergent histories of forest management. Attention to regional distinctions
in the framing of scientific problems is particularly important as scientific frameworks are exported to new places; for example,
both Japanese and American forms of matsutake science have been extended to China.
高価なグルメきのこであるマツタケとその近縁種群のTricholoma属は広範囲に渡る科学的研究の対象となってきた。本論では二つの地域特徴的なマツタケ研究の軌跡を概観し、文化的差異を超えて世界的に通用する近代科学においても地域固有の関心に応じて特徴のある知識が結節し発展することを示す。マツタケ研究の世界的な中心地である日本では人工増殖やマツタケを殖やすための「果樹園的」な山林作りへの関心が基礎研究の方向性に刺激を与えてきた。一方日本とは対照的に、米国北西岸州では木材の持続的産出に主眼をおいた山林管理の流れの中で研究が進んできた。こうした研究計画や結果的に得られる知識の違いは、地域ごとに特徴のある科学的遺産
- 本件の場合は森林管理の歴史が多様に枝分かれしていること - に注目することが重要であることを知らせてくれる。近年日本や米国で発展したマツタケ研究の方法や成果が中国での研究にも影響を与えているが、特に新しい研究の場を広げる場合には科学的な関心、問題がどのような枠組で組み立てられるか地域によって多様であることを考慮することが重要である。 相似文献
13.
The results of genome analysis of five hybrids, viz.Elymus patagonicus ×Hordeum procerum, E. patagonicus ×H. tetraploidum, E. angulatus ×H. jubatum, E. angulatus ×H. lechleri, andE. angulatus ×H. parodii, are reported. The genomic constitution ofHordeum tetraploidum andH. jubatum is best given as H1H1H2H2, ofH. lechleri andH. parodii as H1H1H2H2H4H4, ofH. procerum as H1H1H2H2H3H3, and ofElymus patagonicus andE. angulatus as SSH1H1H2H2. 相似文献
14.
Effect of host plants on the infectivity of nucleopolyhedrovirus to Spodoptera exigua larvae 下载免费PDF全文
Previous studies have shown that the infectivity of baculovirus to herbivores is affected by phytochemicals ingested during the acquisition of viral inoculum on the foliage of host plants. Here, we measured the effects of 14 host plant species on the infectivity of Spodoptera exigua nucleopolyhedrovirus (SeNPV) to its larvae. The order of the LD50 values of SeNPV among the host plants was Ipomoea aquatica > Brassica oleracea > Raphanus sativus > Amaranthus tricolor > Spinacia oleracea > Vigna unguiculata > Solanum melongena > Capsicum annuum > Apium graveolens > Allium fistulosum > Lactuca sativa > Brassica chinensis > Zea mays > Glycine max, with 940.1 ± 2.26, 424.0 ± 0.60, 295.2 ± 1.13, 147.3 ± 0.63, 138.6 ± 0.22, 119.9 ± 0.07, 119.8 ± 0.02, 109.2 ± 0.18, 104.8 ± 0.62, 102.1 ± 0.66, 97.9 ± 0.22, 89.9 ± 0.32, 79.0 ± 0.13 and 64.0 ± 0.38 OBs per larva, respectively, and the values of mean time to death of virus‐infected larvae were 6.21 ± 0.11, 7.12 ± 0.10, 7.33 ± 0.21, 6.97 ± 0.02, 7.06 ± 0.01, 7.29 ± 0.03, 7.32 ± 0.05, 7.07 ± 0.08, 7.24 ± 0.11, 7.09 ± 0.13, 7.50 ± 0.06, 7.23 ± 0.01, 7.30 ± 0.02 and 7.19 ± 0.07 days, respectively. The mean time to death of larvae decreased with increasing viral dose, and corrected mortality decreased as the larval mean time to death increased. These findings have significance for understanding the effects of host plants on the infectivity of baculovirus to noctuids. 相似文献
15.
J. C. Hunter 《Trees - Structure and Function》1997,11(3):169-175
For the angiosperm dominants of northern California’s mixed evergreen forests, this study compares the display of photosynthetic
tissue within leaves and along branches, and examines the correspondence between these morphological attributes and the known
environmental tolerances of these species. Measurements were made on both sun and shade saplings of six species: Arbutus
m
e
n
z
i
e
s
i
i (Ericaceae), C
h
r
y
s
o
l
e
p
i
s
c
h
r
y
s
o
p
h
y
l
l
a (Fagaceae), L
i
t
h
o
c
a
r
p
u
s
d
e
n
s
i
f
l
o
r
u
s (Fagaceae), Quercus
c
h
r
y
s
o
l
e
p
i
s (Fagaceae), Quercus
w
i
s
l
i
z
e
n
i
i (Fagaceae), and Umbellularia
c
a
l
i
f
o
r
n
i
c
a (Lauraceae). All species had sclerophyllous leaves with thick epidermal walls, but species differed in leaf specific weight,
thickness of mesophyll tissues and in the presence of a hypodermis, crystals, secretory idioblasts, epicuticular deposits,
and trichomes. The leaves of Arbutus were 2 – 5 times larger than those of C
h
r
y
s
o
l
e
p
i
s, L
i
t
h
o
c
a
r
p
u
s and Umbellularia and 4 – 10 times larger than those of both Quercus species. Together with differences in branch architecture, these leaf traits divide the species into groups corresponding
to environmental tolerances. Shade-tolerant C
h
r
y
s
o
l
e
p
i
s, L
i
t
h
o
c
a
r
p
u
s, and Umbellularia had longer leaf lifespans and less palisade tissue, leaf area, and crown mass per volume than the intermediate to intolerant
Arbutus and Quercus. Having smaller leaves, Quercus branches had more branch mass per leaf area and per palisade volume than other species, whereas Arbutus had less than other species. These differences in display of photosynthetic tissue should contribute to greater growth for
Quercus relative to the other species under high light and limited water, for Arbutus under high light and water availability, and for C
h
r
y
s
o
l
e
p
i
s, L
i
t
h
o
c
a
r
p
u
s, and Umbellularia under limiting light levels.
Accepted: 22 March 1996 相似文献
16.
Résumé Certains stades juvéniles de charançons des céréales du genreSitophilus ont été soumis à un séjour prolongé dans des compositions gazeuses modifiées par le dioxyde de carbone (CO2).Les auteurs se sont placés dans des conditions de teneur en CO2 constante (50%), associée à des teneurs en oxygène comprises entre 4 et 20%, pour étudier les conditions d'une synergie entre l'effet spécifique du CO2 et la présence d'une forte teneur résiduelle en oxygène. Les effets ont été observés sur les stades juvéniles les plus évolués (larves et nymphes) des espècesS. oryzae (L.) etS. granarius (L.), (Coleoptera: Curculionidae).L'accroissement de la vitesse de mortalité chezS. oryzae est significative avec l'augmentation de la pression partielle d'oxygène. Cet effet de synergie provoqué par l'oxygène n'est pas significatif avecS. granarius, bien qu'il existe aussi avec cette espèce une tendance à l'amélioration de l'efficacité insecticide à court terme avec les mélanges à forte teneur résiduelle en oxygène.Il en est déduit des hypothèses sur les effets des mélanges gazeux à composition modifiée par le CO2 au niveau de la physiologie générale de ces insectes, qui est très difficile à appréhender directement à cause du mode de développement des stades juvéniles des charançons (formes cachées dans le grain). 相似文献
17.
18.
César Román-Valencia Raquel I. Ruiz-C Donald C. Taphorn Carlos A. García-Alzate 《ZooKeys》2014,(454):109-125
Hemibrycon
sanjuanensis, new species, is described from the upper San Juan River drainage, Pacific versant, Colombia. It is distinguished from Hemibrycon
boquiae, Hemibrycon
brevispini, Hemibrycon
cairoense, Hemibrycon
colombianus, Hemibrycon
mikrostiktos, Hemibrycon
metae, Hemibrycon
palomae, Hemibrycon
rafaelense and Hemibrycon
tridens by the presence of a circular or oblong humeral spot that is located two scales posterior to the opercle (vs. 3–4 scales in Hemibrycon
palomae, Hemibrycon
rafaelense, Hemibrycon
brevispini and Hemibrycon
cairoense, and 0–1 scales, in Hemibrycon
metae and Hemibrycon
boquiae). It further differs from Hemibrycon
colombianus in having a round or oblong humeral spot (vs. rectangular). It differs from Hemibrycon
beni, Hemibrycon
dariensis, Hemibrycon
divisorensis, Hemibrycon
helleri, Hemibrycon
huambonicus, Hemibrycon
inambari, Hemibrycon
jabonero, Hemibrycon
jelskii, Hemibrycon
mikrostiktos, Hemibrycon
polyodon, Hemibrycon
quindos, Hemibrycon
raqueliae, Hemibrycon
santamartae, Hemibrycon
surinamensis, Hemibrycon
taeniurus, Hemibrycon
tridens, and Hemibrycon
yacopiae in having melanophores on the posterior margins of the scales along the sides of body (vs. lacking melanophores on margins of scales along entire length of the sides of body). The new species differs from all congeners mentioned above in having, among other features, six teeth in the outer premaxillary row arranged in a straight line (vs. five or fewer teeth not arranged in straight line except Hemibrycon
cairoense with two to six teeth in the outer premaxillary row). 相似文献
19.
When α-d-GlcNAc-OC6H4NO2
-p and β-d-(6-sulfo)-GlcNAc-OC6H4NO2-p (2) were used as substrates, β-N-acetylhexosaminidase from Aspergillus oryzae transferred the β-d-(6-sulfo)-GlcNAc(unit from 2 to α-d-GlcNAc-OC6H4NO2
-p to afford β-d-(6-sulfo)-GlcNAc-(1→4)-α-d-GlcNAc-OC6H4NO2-p (3) in a yield of 94% based on the amount of donor, 2, added. β-d-(6-sulfo)-GlcNAc-(1→4)-α-d-Glc-OC6H4NO2-p (4) was obtained with α-d-Glc-OC6H4NO2
-p as acceptor in a similar manner. With a reaction mixture of 2 and β-d-GlcNAc-OC6H4NO2-p (1) in a molar ratio of 6:1, the enzyme mediated the transfer of β-d-GlcNAc from 1 to 2, affording disaccharide β-d-GlcNAc-(1→4)-β-(6-sulfo)-d-GlcNAc-OC6H4NO2-p (5) in a yield of 13% based on the amount of 1 added. 相似文献
20.
N. D. Jambhale Y. S. Nerkar 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1985,71(1):122-125
Summary Genetic studies on radiation-induced chlorina and variegated mutants of okra (Abelmoschus esculentus (L.) Moench) revealed the existence of an unstable gene. The normal green color of the leaves is controlled by duplicate genes C1 and C2, either of which produces the green colour. The chlorina plants are C
1
C
1
C
2
C
2. The allele c
1
v
is dominant to both C
1 and C
2 but is unstable. The homozygote c
1
v
c
1
v
c
2
c
2 is a normal green while the heterozygote c
i
v
c
1
c
2
c
2 has a variegated phenotype as a result of the mutation of c
1
v
to c
1 during development. In green plants with a c
1
v
c{sh1/v}c
2
c
2 genotype, the autonomous mutation of one of the c
1
v
alleles to c
1 may take place at the pre-meiotic stage. In the variegated genotype (c
1
v
c
1
c
2
c
2), the mutation of c
1 to c
1
v
may take place in early ontogeny, thus producing green plants. The allele C
1, when associated with c
1
v
in a heterozygous condition, mutates to c
1 at the pre-meiotic stage even in the presence of the allele C
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