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Prospective protochordate homologs of vertebrate midbrain and MHB, with some thoughts on MHB origins
Thurston C. Lacalli
International Journal of Biological Sciences , 2006,
Abstract: The MHB (midbrain-hindbrain boundary) is a key organizing center in the vertebrate brain characterized by highly conserved patterns of gene expression. The evidence for an MHB homolog in protochordates is equivocal, the "neck" region immediately caudal to the sensory vesicle in ascidian larvae being the best accepted candidate. It is argued here that similarities in expression patterns between the MHB and the ascidian neck region are more likely due to the latter being the principal source of neurons in the adult brain, and hence where all the genes involved in patterning the latter will necessarily be expressed. The contrast with amphioxus is exemplified by pax2/5/8, expressed in the neck region in ascidian larvae, but more caudally, along much of the nerve cord in amphioxus. The zone of expression in each case corresponds with that part of the nerve cord ultimately responsible for innervating the adult body, which suggests the spatially restricted MHB-like expression pattern in ascidians is secondarily reduced from a condition more like that in amphioxus. Patterns resembling those of the vertebrate MHB are nevertheless found elsewhere among metazoans. This suggests that, irrespective of its modern function, the MHB marks the site of an organizing center of considerable antiquity. Any explanation for how such a center became incorporated into the chordate brain must take account of the dorsoventral inversion chordates have experienced relative to other metazoans. Especially relevant here is a concept developed by Claus Nielsen, in which the brain is derived from a neural center located behind the ancestral mouth. While this is somewhat counterintuitive, it accords well with emerging molecular data.
Genetic dissection of medial habenula–interpeduncular nucleus pathway function in mice  [PDF]
Yuki Kobayashi,Yoshitake Sano,Elisabetta Vannoni,Hiromichi Goto,Hitomi Suzuki,Atsuko Oba,Hiroaki Kawasaki,Shigenobu Kanba,Hans-Peter Lipp,Niall P. Murphy,David P. Wolfer,Shigeyoshi Itohara
Frontiers in Behavioral Neuroscience , 2013, DOI: 10.3389/fnbeh.2013.00017
Abstract: The habenular complex linking forebrain and midbrain structures is subdivided into the medial (mHb) and the lateral nuclei (lHb). The mHb is characterized by the expression of specific nicotinic acetylcholine receptor isoforms and the release of acetylcholine to the interpeduncular nucleus (IPN), the sole output region of the mHb. The specific function of this circuit, however, is poorly understood. Here we generated transgenic mice in which mHb cells were selectively ablated postnatally. These lesions led to large reductions in acetylcholine levels within the IPN. The mutant mice exhibited abnormalities in a wide range of behavioral domains. They tended to be hyperactive during the early night period and were maladapted when repeatedly exposed to new environments. Mutant mice also showed a high rate of premature responses in the 5-choice serial reaction time task (5-CSRTT), indicating impulsive and compulsive behavior. Additionally, mice also exhibited delay and effort aversion in a decision-making test, deficits in spatial memory, a subtle increase in anxiety levels, and attenuated sensorimotor gating. IntelliCage studies under social housing conditions confirmed hyperactivity, environmental maladaptation, and impulsive/compulsive behavior, delay discounting, deficits in long-term spatial memory, and reduced flexibility in complex learning paradigms. In 5-CSRTT and adaptation tasks, systemic administration of nicotine slowed down nose-poke reaction and enhanced adaptation in control but not mutant mice. These findings demonstrate that the mHb–IPN pathway plays a crucial role in inhibitory control and cognition-dependent executive functions.
MRN-100, An Iron-Based Compound, Possesses Anti-HIV Activity In Vitro  [PDF]
Mamdooh Ghoneum,Magda Shaheen
Evidence-Based Complementary and Alternative Medicine , 2010, DOI: 10.1093/ecam/nen019
Abstract: We examined the in vitro anti-human immunodeficiency virus (HIV) activity of MRN-100, an iron-based compound derived from bivalent and tervalent ferrates. MRN-100 action against HIV-1 (SF strain) was tested in primary cultures of peripheral blood mononuclear cells (MNC) by analyzing p24 antigen production and percent survival of MNC infected with HIV. MRN-100 at a concentration of 10% (v/v) inhibited HIV-1 replication in 11 out of 14 samples (79%). The percentage of suppression of p24 antigen was ?12.3 to 100% at 10 days post-treatment. MRN-100 also exhibited a significant protective effect in the survival of HIV-1-infected MNC. MNC survival post-treatment was dose dependent, 70.4% ± 8.4, 83.6% ± 10.7 and 90% ± 11.4, at concentrations 2.5, 5 and 10% (v/v), respectively, as compared with 53% ± 4 for HIV-1-infected MNC without treatment. The effect was detected as early as 4 days and continued up to 11 days. Treatment with MRN-100 caused no significant change in proliferative response of MNC alone or cocultured with different mitogens: PHA and Con-A (activators of T cell function) and PWM (activator of CD4+ T cell-dependent B cells). We concluded that MRN-100 possesses anti-HIV activity in vitro and without an increase in lymphocyte proliferation, MRN-100 may be a useful agent for treating patients with acquired immunodeficiency syndrome.
水泥混凝土路面MHB法碎石化环境影响分析与评价  [PDF]
阎宗岭,高艳龙,冯学钢
公路交通科技 , 2008,
Abstract: 为了掌握既有水泥混凝土路面MHB法碎石化改造时对周围环境的振动特点与影响范围,采用高精度震动测试仪对水泥混凝土路面MHB法碎石化时的施工振动特点、影响范围等进行了现场施工监测。对试验段现场振动测试的振动加速度时程曲线、加速度衰减特性曲线和加速度峰值随振中距衰减曲线的变化进行了对比、分析。表明采用MHB法对旧混凝土路面碎石化施工时所产生的机械振动加速度衰减速度很快,且具有冲击和瞬态振动的特点,对以填方为主在路堤边坡和挖方路堑边坡的安全影响范围与岩土体性质密切相关。通过试验建立了填方路基和挖方边坡的水平加速度和垂直加速度与MHB法碎石化振中距间的负指数和对数关系式,确定了混凝土路面MHB法碎石化振动对填方路基下边坡和挖方路堑上边坡上建筑物影响范围和最小安全距离,分别为5.5m和25m。
冲击压实与MHB类设备对水泥混凝土路面破碎效果的对比  [PDF]
李昶,张玉宏,张建
公路交通科技 , 2004,
Abstract: 常规方式处理破坏严重的水泥混凝土路面时存在效率低、费用高的缺点,目前我国逐渐采用冲击压实设备进行破碎的工艺,山东省公路局近年又引进了MHB(MultipleHeadBreaker,多锤头破碎机)类水泥混凝土路面碎石化(Rubblization)设备。本文主要从破碎效果对2种设备进行对比,通过2种工艺破碎后表面回弹弯沉及回弹模量等测试数据,分析2种工艺处治后结构层表面的强度变异性。结果显示,MHB设备破碎的水泥混凝土路面具有更好的强度均匀性,可以作为新加铺路面的基层。
MRN1 Implicates Chromatin Remodeling Complexes and Architectural Factors in mRNA Maturation  [PDF]
Louis Düring, Michael Thorsen, Darima Sophia Njama Petersen, Brian K?ster, Torben Heick Jensen, Steen Holmberg
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044373
Abstract: A functional relationship between chromatin structure and mRNA processing events has been suggested, however, so far only a few involved factors have been characterized. Here we show that rsc nhp6ΔΔ mutants, deficient for the function of the chromatin remodeling factor RSC and the chromatin architectural proteins Nhp6A/Nhp6B, accumulate intron-containing pre-mRNA at the restrictive temperature. In addition, we demonstrate that rsc8-ts16 nhp6ΔΔ cells contain low levels of U6 snRNA and U4/U6 di-snRNA that is further exacerbated after two hours growth at the restrictive temperature. This change in U6 snRNA and U4/U6 di-snRNA levels in rsc8-ts16 nhp6ΔΔ cells is indicative of splicing deficient conditions. We identify MRN1 (multi-copy suppressor of rsc nhp6ΔΔ) as a growth suppressor of rsc nhp6ΔΔ synthetic sickness. Mrn1 is an RNA binding protein that localizes both to the nucleus and cytoplasm. Genetic interactions are observed between 2 μm-MRN1 and the splicing deficient mutants snt309Δ, prp3, prp4, and prp22, and additional genetic analyses link MRN1, SNT309, NHP6A/B, SWI/SNF, and RSC supporting the notion of a role of chromatin structure in mRNA processing.
An iron-based beverage, HydroFerrate fluid (MRN-100), alleviates oxidative stress in murine lymphocytes in vitro
Mamdooh Ghoneum, Motohiro Matsuura, Sastry Gollapudi
Nutrition Journal , 2009, DOI: 10.1186/1475-2891-8-18
Abstract: Splenic lymphocytes from mice were cultured in the presence or absence of MRN-100 for 2 hrs and were subsequently exposed to hydrogen peroxide (H2O2) at a concentration of 25 μM for 14 hrs. Percent cell death was examined by flow cytometry and trypan blue exclusion. The effect of MRN-100 on Bcl-2 and Bax protein levels was determined by Western blot.Results show, as expected, that culture of splenic cells with H2O2 alone results in a significant increase in cell death (apoptosis) as compared to control (CM) cells. In contrast, pre-treatment of cells with MRN-100 followed by H2O2 treatment results in significantly reduced levels of apoptosis.In addition, MRN-100 partially prevents H2O2-induced down-regulation of the anti-apoptotic molecule Bcl-2 and upregulation of the pro-apoptotic molecule Bax.Our findings suggest that MRN-100 may offer a protective effect against oxidative stress-induced apoptosis in lymphocytes.Oxidative stress represents the imbalance between the cellular production of oxidants and the capacity of cellular antioxidant defenses to scavenge these oxidants. It is produced in cells by oxygen-derived species which include free radicals and peroxides; it is also produced at a low level by normal aerobic metabolism and nutritional deficiency in trace metal [1,2]. Increasing evidence indicates that oxidative stress is a major inducer of cell death [3]. In this process some of the reactive oxygen species (such as superoxide) are converted into hydrogen peroxide which can cause controlled apoptotic cell death [4,5].Oxidative stress is associated with many diseases, including chronic inflammation, arteriosclerosis, diabetes, stroke, Alzheimer's and Parkinson's diseases, and aging [6-8]. In addition, nutritional deficiencies like lack of iron have been shown to induce oxidative stress [9,10] and currently affect over 2 billion people worldwide. Thus far, the ability of iron to protect against oxidative stress has only been studied to a limited extent [11].I
MHB碎石化动力响应及其对邻近建筑和居民的振动影响  [PDF]
李萍,念腾飞,张雅莉,毛昱,乔雄
- , 2018,
Abstract: MHB碎石化技术广泛应用于改建工程中旧水泥混凝土路面破碎,但冲击破碎过程中对邻近建筑和居民的振动影响问题亟待解决.基于弹性理论和波动理论对冲击荷载下路面板的物理参数衰减规律进行推导分析;依托山东S245省道旧水泥混凝土路面改建工程现场振动监测试验,并结合ANSYS/LS-DYNA动力有限元数值模拟对不同影响因素下路面板的三向动力响应进行研究,探寻碎石化邻近建筑物水平安全距离和影响居民舒适度的临界距离.结果表明:MHB碎石化施工振动属于冲击型振源,振动以负幂指数形式衰减,且计算、实测和数值模拟结果曲线衰减趋势一致;随着冲程的增大,碎石化动力荷载峰值出现时间不断提前;振动速度峰值1 cm/s可作为判断邻近建筑安全与否的控制指标;当重锤下落高度分别为0.8 m、1.0 m、1.2 m时,临近建筑物水平安全距离分别为14 m、18 m、20 m,影响居民舒适度的临界距离分别为24 m、29 m、和31 m.
MHB rubblization technology is widely used in the reconstruction of the old cement concrete pavement (PCC) crushing, however, the impact of vibration on the adjacent buildings and residents during the impact crushing process needs to be urgently resolved. The attenuation law of physical parameters of the pavement panel under impact load were deduced and analyzed based on elastic theory and wave theory. Relying on the field vibration monitoring test on the old PCC pavement reconstruction project of Shandong provincial highway S245, and combing with ANSYS/LS-DYNA dynamic finite element numerical simulation, the three-dimensional dynamic response under different influence factors was studied. Then, the level safety distance of rubblization adjacent buildings and the comfortability critical distance of the residents were explored. The results show that MHB rubblization belongs to impact type vibration source, whose vibration is a negative exponential curve in the form of a sharp attenuation, and the results of calculation, measurement and numerical simulation are in agreement with the attenuation trend of the curve. With increasing stroke the peak time load continuously advances. The peak vibration velocity of 1cm/s can be used as a control index for judging the safety of adjacent building. When the hammer drop height is 0.8 m, 1.0 m, 1.2 m respectively, the level safety distance of adjacent building is 14 m, 18 m, 20 m respectively, and the comfortability critical distance of inhabitants is 24 m, 29 m, 31 m respectively.
一株菌根辅助细菌(MHB)芽孢杆菌Bacillus sp.对杨树生长的影响  [PDF]
,,吴小芹,叶建仁
南京林业大学学报(自然科学版) , 2015, DOI: 10.3969/j.issn.1000-2006.2015.01.005
Abstract: 为探讨菌根辅助细菌(MHB)对杨树生长的影响,在温室条件下,将筛选到的菌根辅助细菌芽孢杆菌Bacillus sp. DZ18分别与两种外生菌根真菌彩色豆马勃(Pisolithus tinctorius(Pers.)Coker & Couch,Pt2)、劣味乳菇(Lactarius insulsus Fr. Li)双接种于1年生美洲黑杨(Populus deltoides),处理120 d后,测定菌根形成率以及对杨树苗高、地径、根生物量、茎生物量、光合作用、矿物质代谢能力的影响。结果表明,芽孢杆菌DZ18与Pt2、Li双接种时与单接种Pt2、Li相比显著提高了杨树的菌根形成率,且无论单接种DZ18还是DZ18与两种外生菌根真菌双接种均对杨树的各项生长指标具有显著的促进作用。
The present greenhouse study was undertaken to evaluate the effects of co-inoculating the ectomycorrhizal(ECM)fungus Pisolithus tinctorius(Pers.)Coker & Couch(Pt2), Lactarius insulsus Fr.(Li)with the mycorrhiza helper bacterium Bacillus sp. DZ18 on the growth of poplar seedlings. After 120 days treatment, ectomycorrhizal colonization rate, shoot length, root crown diameter, root biomass, stem biomass, photosynthesis, and mineral metabolism ability of poplar were measured. The results showed that Bacillus DZ18 coinoculated with Pisolithus tinctorius(Pt2)or Lactarius insulsus(Li)significantly improved mycorrhizal formation rate of poplar compared with a single inoculation Pt2 or Li, and whether single inoculation DZ18 or DZ18 coinoculation with Pt2 and Li, the poplar growth indices were significantly promoted. Therefore, MHB strain DZ18 had potential value to become an excellent bio-fertilizer strain resources
Genetic drift opposes mutualism during spatial population expansion  [PDF]
Melanie JI Muller,Beverly I Neugeboren,David R Nelson,Andrew W Murray
Quantitative Biology , 2014, DOI: 10.1073/pnas.1313285111
Abstract: Mutualistic interactions benefit both partners, promoting coexistence and genetic diversity. Spatial structure can promote cooperation, but spatial expansions may also make it hard for mutualistic partners to stay together, since genetic drift at the expansion front creates regions of low genetic and species diversity. To explore the antagonism between mutualism and genetic drift, we grew cross-feeding strains of the budding yeast S. cerevisiae on agar surfaces as a model for mutualists undergoing spatial expansions. By supplying varying amounts of the exchanged nutrients, we tuned strength and symmetry of the mutualistic interaction. Strong mutualism suppresses genetic demixing during spatial expansions and thereby maintains diversity, but weak or asymmetric mutualism is overwhelmed by genetic drift even when mutualism is still beneficial, slowing growth and reducing diversity. Theoretical modeling using experimentally measured parameters predicts the size of demixed regions and how strong mutualism must be to survive a spatial expansion.
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