Evolution of xyloglucan-related genes in green plants

Background  

The cell shape and morphology of plant tissues are intimately related to structural modifications in the primary cell wall that are associated with key processes in the regulation of cell growth and differentiation. The primary cell wall is composed mainly of cellulose immersed in a matrix of hemicellulose, pectin, lignin and some structural proteins. Xyloglucan is a hemicellulose polysaccharide present in the cell walls of all land plants (Embryophyta) and is the main hemicellulose in non-graminaceous angiosperms.     

Structural requirements of carbohydrates to bind Agaricus bisporus lectin

Galbeta1-3GalNAc (T-disaccharide) and related molecules were assayed to describe the structural requirements of carbohydrates to bind Agaricus bisporus lectin (ABL). Results provide insight into the most relevant regions of T-disaccharide involved in the binding of ABL. It was found that monosaccharides bind ABL weakly indicating a more extended carbohydrate-binding site as compared to those involvedin the T- disaccharide specific lectins such as jacalin and peanut agglutinin. Lacto-N-biose (Galbeta1-3GlcNAc) unlike T-disaccharide, is unable to inhibit the ABL interaction, thus showing the great importance of the position of the axial C-4 hydroxyl group of GalNAc in T-disaccharide. This finding could explain the inhibitory ability of Galbeta1-6GlcNAc and lactose because C-4 and C-3 hydroxyl groups of reducing Glc, respectively, occupy a similar position as reported by conformational analysis. From the comparison of different glycolipids bearing terminal T-disaccharide bound to different linkages, it can be seen than ABL binding is even more impaired by an adjacent C-6 residual position than by the anomeric influence of T-disaccharide. Furthermore, the addition of beta-GlcNAc to the terminal T-disaccharide in C-3 position of Gal does not affect the ABL binding whereas if an anionic group such as glucuronic acid is added to C-3, the binding is partially affected. These findings demonstrate that ABL holds a particular binding nature different from that of other T-disaccharide specific lectins.      

脂多糖通过补体途径诱导小鼠产生白三烯B4

目的:研究脂多糖(LPS)对人血清中补体系统的激活及在小鼠模型中诱导产生白三烯B4(LTB4)。方法:LPS包被ELISA板,利用血清中补体C4、C3沉积实验检测补体成分被LPS活化的情况,通过尾静脉注射小鼠LPS后不同时间点ELISA定量检测LTB4,评价补体系统的活化和炎症因子的产生。结果与结论:血清系统ELISA检测发现LPS可以激活补体系统,且以凝集素途径为主;动物实验中LTB4被LPS诱导后1～3 h达到峰值,之后回落。C1INH对血清补体活化和动物模型中LTB4的产生均有显著抑制。     

The structure-function organization of neurokinin A and neurokinin B molecules. II. Theoretical conformational analysis of neurokinin B

The spatial structure of a neurokinin B molecule was investigated by the method of theoretical conformational analysis. The conformational analysis of this molecule indicated that the possible structure of neurokinin B under polar conditions may be described by five families of low-energy conformations possessing a conformationally relatively rigid C-terminal heptapeptide and variable N-terminal fragments.     

Conformational features of a pentapeptide as an element of the active center of human immunoglobulin E

The spatial structures of human immunoglobulin E pentapeptide Asp-Ser-Asp-Pro-Arg and some of its related peptides were investigated by the method of theoretical conformational analysis. These synthetic peptides have the capacity to inhibit the binding of immunoglobulin E to the mast cells of the skin. The results of the calculations and the data on biological activity of these peptides were used for determination their energy-dependent conformational characteristics that provide their specific interaction with receptors of mast cells.     

氨氯地平联合依那普利治疗原发性高血压的临床疗效及对患者左心室肥厚的影响

摘要目的：探讨氨氯地平联合依那普利治疗原发性高血压的临床效果,观察联合用药对左心室肥厚的影响。方法：选择本院收治的原发性高血压患者92例,随机分为观察组和对照组,各46例,对照组给予苯磺酸左旋氨氯地平5mg,1次／d,口服;观察组在对照组基础上加用马来酸依那普利10mg,2次／d,口服,疗程均为24周。观察两组治疗前后血压变化,应用超声心动图测量两组左心室厚度变化。结果：治疗后,观察组总有效率为91_3％;对照组总有效率为73．9％,观察组总有效率高于对照组（P〈0．05）。治疗前两组心率、血压比较无统计学差异（P〉0．05）,治疗后两组血压均明显降低,观察组收缩压、舒张压明显低于对照组（P〈O．05）;观察组心率明显低于对照组（P〈0．01）。治疗前两组左心室舒张末期室间隔厚度（Leaventricularend—diastolicventricularseptalthickness,IVST）、左心室后壁厚度（1eftventricularposteriorwallthickness,U,PwT）和左室射血分数（Leftventricularejectionfxaction,LVEF）比较无统计学差异（P〉0．05）;治疗后观察组IVST、L、,PwT明显低于对照组,LVEF明显高于对照组（P〈0．05）。结论：氨氯地平联合依那普利治疗原发性高血压能有效扭转左心室肥厚,降压效果较单独应用氨氯地平更佳。     

重组人MASP2蛋白在大肠杆菌中的表达和纯化

目的:获得酶原形式的重组人甘露聚糖结合凝集素相关丝氨酸蛋白酶2(MASP2)。方法:在大肠杆菌中诱导表达重组人MASP2全长蛋白,包涵体裂解后,经复性、透析、浓缩、考马斯亮蓝染色、SDS-PAGE及Western印迹,鉴定纯化结果及酶活性。结果:复性后的MASP2蛋白经考马斯亮蓝染色未见杂带。自激活实验表明,当MASP2浓度在1μmool/L以下时,无论在4℃还是37℃,都能较稳定地保持酶原形式;蛋白浓度为3.5μmool/L时只能在4℃保持稳定,37℃发生自激活;蛋白浓度达到12μmool/L后,在4℃时已不能稳定存在。结论:获得了较纯的重组人MASP2蛋白,且具有自激活活性。     

Within‐plant distribution of 1,4‐benzoxazin‐3‐ones contributes to herbivore niche differentiation in maize

Plant defences vary in space and time, which may translate into specific herbivore‐foraging patterns and feeding niche differentiation. To date, little is known about the effect of secondary metabolite patterning on within‐plant herbivore foraging. We investigated how variation in the major maize secondary metabolites, 1,4‐benzoxazin‐3‐one derivatives (BXDs), affects the foraging behaviour of two leaf‐chewing herbivores. BXD levels varied substantially within plants. Older leaves had higher levels of constitutive BXDs while younger leaves were consistently more inducible. These differences were observed independently of plant age, even though the concentrations of most BXDs declined markedly in older plants. Larvae of the well‐adapted maize pest Spodoptera frugiperda preferred and grew better on young inducible leaves irrespective of plant age, while larvae of the generalist Spodoptera littoralis preferred and tended to grow better on old leaves. In BXD‐free mutants, the differences in herbivore weight gain between old and young leaves were absent for both species, and leaf preferences of S. frugiperda were attenuated. In contrast, S. littoralis foraging patterns were not affected. In summary, our study shows that plant secondary metabolites differentially affect performance and foraging of adapted and non‐adapted herbivores and thereby likely contribute to feeding niche differentiation.     

Effect of a Sound Stimulus on Postural Reactions

The effect of a sound stimulus on postural responses was studied in five subjects (four females and one male). Sound stimuli were noise signals successively applied to loudspeakers placed along an arc, simulating movement of a sound source. A subject stood on a platform centered relative to the arc so that the sagittal plane of the subject coincided with the plane of the arc. Stabilograms of the body's general center of gravity (GCOG) were recorded for 15 s, including 6 s of silence, auditory stimulation (1.6, 3.2, or 4.8 s), and silence after the signal was cut off. A slight decrease in the amplitude of displacement of the GCOG was observed during auditory stimulation. For a signal duration of 4.8 s, a slight forward shift of the GCOG was observed in the sagittal plane, in which the auditory image moved.