Electrophoretic profiling and immunocytochemical detection of pectins and arabinogalactan proteins in olive pollen during germination and pollen tube growth

Background and Aims

Cell wall pectins and arabinogalactan proteins (AGPs) are important for pollen tube growth. The aim of this work was to study the temporal and spatial dynamics of these compounds in olive pollen during germination.

Methods

Immunoblot profiling analyses combined with confocal and transmission electron microscopy immunocytochemical detection techniques were carried out using four anti-pectin (JIM7, JIM5, LM5 and LM6) and two anti-AGP (JIM13 and JIM14) monoclonal antibodies.

Key Results

Pectin and AGP levels increased during olive pollen in vitro germination. (1 → 4)-β-d-Galactans localized in the cytoplasm of the vegetative cell, the pollen wall and the apertural intine. After the pollen tube emerged, galactans localized in the pollen tube wall, particularly at the tip, and formed a collar-like structure around the germinative aperture. (1 → 5)-α-l-Arabinans were mainly present in the pollen tube cell wall, forming characteristic ring-shaped deposits at regular intervals in the sub-apical zone. As expected, the pollen tube wall was rich in highly esterified pectic compounds at the apex, while the cell wall mainly contained de-esterified pectins in the shank. The wall of the generative cell was specifically labelled with arabinans, highly methyl-esterified homogalacturonans and JIM13 epitopes. In addition, the extracellular material that coated the outer exine layer was rich in arabinans, de-esterified pectins and JIM13 epitopes.

Conclusions

Pectins and AGPs are newly synthesized in the pollen tube during pollen germination. The synthesis and secretion of these compounds are temporally and spatially regulated. Galactans might provide mechanical stability to the pollen tube, reinforcing those regions that are particularly sensitive to tension stress (the pollen tube–pollen grain joint site) and mechanical damage (the tip). Arabinans and AGPs might be important in recognition and adhesion phenomena of the pollen tube and the stylar transmitting cells, as well as the egg and sperm cells.     

Bacterial diversity in biofilms formed on condenser tube surfaces in a nuclear power plant

To elucidate the bacterial diversity in biofilms formed on a condenser tube from a nuclear power plant, 16S rRNA gene sequences were examined using a PCR-cloning-sequencing approach. Twelve operational taxonomic units were retrieved in the clone library, and the estimated species richness was low (13.2). Most of the clones (94.7%) were affiliated with α-Proteobacteria; Planctomycetes and γ-Proteobacteria were much rarer. Interestingly, except for one clone belonging to Pseudoalteromonas, most of the sequences displayed sequence similarities <97% of those of the closest type strains. Based on 16S rRNA phylogenetic analysis, most bacteria were assigned to novel taxa above the species level. The low species richness and unusual bacterial composition may be attributable to selective pressure from chlorine in the cooling water. To prevent or control bacterial biofilms in cooling circuits, additional studies of the physiology and ecology of these species will be essential.     

The influence of the progamic phase for fruiting in the apple tree

Final fruit production is the result of a number of processes, over which several environmental circumstances interact. But it is often difficult to disentangle the part played by each of these factors in the final crop. The aim of this work is to evaluate the influence of the progamic phase for fruiting in the apple tree. For this purpose we track back the process that goes from flower to fruit, identifying the inflection points where the final crop is reduced. We evaluate early versus late fruit development, pollination versus non‐pollination, and the effect of the progamic phase that goes from pollination to fertilization. From flowers to fruits 15 weeks elapsed, but the final fruit set settled 8 weeks after flowering, and the main flower–fruit drop occurred 3–4 weeks after flowering. Differences between dropped fruits and those that remained in the tree emerged earlier, and the onset of fruiting started 7 days after pollination. This time was coincident with the time lapse of the progamic phase. These results show that fruiting gets established well ahead of cropping, but also that the progamic phase is the main determinant of the final fruit set in apple trees.     

COMPACT DISC REVIEW

ABSTRACT

In previous studies, calling sites of two species of burrowing frogs Eupsophus in southern Chile have been shown to amplify conspecific vocalizations generated externally, thus providing a means to enhance the reception of neighbour's vocalizations in breeding aggregations. In the current study the amplification of vocalizations of Eusophus roseus was investigated to explore the extent of sound enhancement reported previously for two congeneric species. Advertisement calls broadcast through a loudspeaker placed in the vicinity of a burrow, monitored with small microphones, are amplified by up to 14 dB inside cavities relative to outside. The fundamental resonant frequency of burrows, measured with broadcast noise and pure tones, ranges from 345–1335 Hz; however it is not correlated with burrow length. The spectra of incoming calls are altered inside burrows by predominantly increasing the amplitude of lower relative to higher harmonics. The call amplification effect inside burrows of E. roseus parallels the effect reported previously for two congeneric species and reinforces the suggestion that sound enhancement inside calling sites has a widespread effect on signal reception by burrowing animals.     

抑制瘢痕细胞中串珠素表达对Ⅰ型胶原蛋白生成量的影响

目的：硬膜外瘢痕,又叫硬膜外纤维化,是指在硬膜外腔的手术涉及范围内形成的瘢痕组织或纤维化,是机体对创伤的修复反应。瘢痕的粘连和收缩会牵拉硬膜和神经根,限制其活动,被瘢痕包绕的神经根受到非正常的牵拉和挤压,神经纤维的轴浆运输、动脉血供、静脉回流受阻,神经根和背侧神经节对机械压迫很敏感,会产生一系列症状,如疼痛、麻木及下肢肌力降低等。近年来,对硬膜外瘢痕防治的研究大多是椎板切除术后如何通过物理或化学屏障来减少术后因瘢痕粘连导致的并发症。但对通过瘢痕形成过程中抑制其主要构成成分的生成来减轻椎板切除术后硬膜外瘢痕形成的相关研究还较少。通过减少椎板切除术后硬膜外瘢痕主要成分Ⅰ型胶原蛋白的生成来实现抑制椎板切除术后硬膜外瘢痕的形成。方法：选用30只250克两月鼠龄的SD雄性大鼠随机按1、2、3、4、5、6周分为6组,行后路4、5腰椎全椎板切除术。术后1、2、3、4、5、6周时每周取一组大鼠全锥板切除术后硬膜后方瘢痕组织,分别行病理切片HE染色,组织块贴壁法细胞培养。筛选第三周瘢痕组织培养的成纤维细胞进行慢病毒干扰串珠素表达并设对照组,通过Western-blot、RT-PCR分析Ⅰ型胶原蛋白生成量与对照组的差别并进行统计学分析。结果：慢病毒干扰小组Ⅰ型胶原蛋白生成量较对照组及纯病毒组明显减少（RT-PCR F=509.331,q A,B=-43.371,P〈0.01,q A,C=-46.133,P〈0.01,Western-Blot F=337.578;q A,B=-112.433,P〈0.01,q A,C=-89.227,P〈0.01）。结论：干扰串珠素表达能有效减少术后硬膜外瘢痕成纤维细胞生成Ⅰ型胶原蛋白,对抑制椎板切除术后硬膜外瘢痕形成应有一定作用。通过慢病毒介导的shRNA干扰成纤维细胞中的串珠素后,其生成的Ⅰ型胶原蛋白量与对照组相比较差异有统计学意义（P〈0.05）,这说明通过抑制瘢痕成纤维细胞的串珠素表达能够有效减少Ⅰ型胶原蛋白的生成。这种方法不论从Ⅰ型胶原蛋白是瘢痕主要构成成分方面,还是Ⅰ型胶原蛋白在瘢痕生成过程中分泌胶原中占得比例增多导致机体由胎儿期的无瘢痕愈合转化至成体的瘢痕愈合这个方面来将,理论上都能够做到有效地抑制、减少硬膜外瘢痕的形成,因此通过干扰硬膜外成纤维细胞串珠素表达从而达到抑制硬膜外瘢痕的形成这一理论是可行的,为进一步进行椎板切除术后抑制硬膜外瘢痕形成的体内试验奠定了理论基础。     

电子胃镜下行食管破裂修补术治疗食管破裂患者的护理体会(附1病例报道)

目的:分析并总结食管破裂的患者急诊住院后经过系统、科学、快速的护理手段和临床治疗,及使用特殊的治疗方法(借助电子胃镜行食管破裂的修补治疗)得到救治的过程中的护理体会.方法:入院后急检血常规、血型、凝血象、生化系列等相关检查;给予禁食水,重症监护,对症处理,营养支持,胸腔闭式引流术排出引流液,应用敏感抗生素等治疗方法;给予科学的严密护理(生命体征的监测护理、严密观察体温的变化及对症处理、胃管的护理、胸腔闭式引流管的护理、心里支持的护理).结果:通过上述方法,患者在无明显并发症发生的情况下,最终在较短的时间内顺利痊愈出院.结论:与常规开胸下行食管破裂修补术治疗食管破裂的患者相比,在电子胃镜下行食管破裂修补术拥有治疗时间短,恢复快,住院时间短,患者医疗费降低等优点.     

Pollen size strongly correlates with stigma depth among Pedicularis species

Darwin proposed that pollen size should be positively correlated with stigma depth rather than style length among species given that pollen tubes first enter the stigma autotrophically, then grow through the style heterotrophically. However, studies often show a positive relationship between pollen size and style length.Five floral traits were observed to be correlated among42 bumblebee-pollinated Pedicularis species(Orobanchaceae) in which stigmas are distinct from styles. The phylogenetic independent contrast analysis revealed that pollen grain volume was more strongly correlated with stigma depth than with style length, consistent with Darwin's functional hypothesis between pollen size and stigma depth.     

管状胃代食管术与全胃代食管术治疗食管癌的安全性与有效性对比

目的:对比管状胃代食管术与全胃代食管术治疗食管癌的安全性与有效性。方法:2005年1月到2015年2月选择我院收治的100例食管癌患者,根据随机数字表法分为治疗组与对照组各50例,所有患者都行食管癌切除术,同时对照组给予全胃代食管手术,治疗组给予管状胃代食管术,对两组患者围手术指标、并发症及生活质量状况进行观察比较。结果:所有患者完成手术,治疗组的手术时间、术中出血量、术后住院时间、术后胃肠减压时间及术后闭式引流时间都明显少于对照组(P0.05)。治疗组术后3个月反流性食管炎、胃排空障碍、胸胃综合征、吻合口狭窄、吻合口瘘等并发症发生情况明显少于对照组(P0.05),日常生活、一般状况、治疗相关症状、社会影响、情感活动评分都明显高于对照组(P0.05)。结论:相对于全胃代食管术,管状胃代食管术在治疗食管癌患者中的应用具有更好的安全性与有效性,值得进一步临床研究与推广。