青海高原中华双腔吸虫等四种双腔吸虫成熟尾蚴的扫描电镜比较观察

青海高原中华双腔吸虫,矛形双腔吸虫等四种双腔吸虫尾蚴经扫描电镜比较观察显示它们体表具有明显的差别。中华双腔吸虫尾蚴体部末部表皮呈具间隔的纵嵴,矛形双腔吸虫尾蚴在此部位呈如同玉米棒的玉米珠粒,未定名的“B”型和“D”型尾蚴,前者呈海棉状,后者介于矛形双腔和中华双腔的形态之间。这四种尾蚴的口吸盘、腹吸盘及体两侧表皮上,具有触毛及乳突的情况亦不相同。     

Ultrastructural comparison of incompatible and compatible interactions in the barley powdery mildew disease

Summary In the powdery mildew disease of barley,Erysiphe graminis f. sp.hordei forms an intimate relationship with compatible hosts, in which haustoria form in epidermal cells with no obvious detrimental effects on the host until late in the infection sequence. In incompatible interactions, by contrast, the deposition of papillae and localized host cell death have been correlated with the cessation of growth byE. g. hordei. With the advent of improved, low temperature methods of sample preparation, we felt that it was useful to reevaluate the structural details of interactions between barley andE. g. hordei by transmission electron microscopy. The haustoria that develop in susceptible barley lines appear highly metabolically active based on the occurrrence of abundant endoplasmic reticulum, Golgi-like cisternae, and vesicles. In comparison, haustoria found in the resistant barley line exhibited varying signs of degradation. A striking clearing of the matrix and loss of cristae were typical early changes in the haustorial mitochondria in incompatible interactions. The absence of distinct endoplasmic reticulum and Golgi-like cisternae, the formation of vacuoles, and the occurrence of a distended sheath were characteristic of intermediate stages of haustorial degeneration. At more advanced stages of degeneration, haustoria were dominated by large vacuoles containing membrane fragments. This process of degeneration was not observed in haustoria ofE. g. hordei developing in the susceptible barley line.Abbreviations b endoplasmic reticulum extension, blebbing - er endoplasmic reticulum - f fibrillar material - g Golgi-like structure - h haustorium - hb haustorial body - hcw haustorial cell wall - hcy haustorial cytoplasm - hf haustorial finger - hocw host cell wall - hocy host cytoplasm - 1 lipid-like droplet - m mitochondrion - mt microtubule - mve multivesicular body - n nucleus - p papilla - ph penetration site of an infection peg - pl plasma membrane - s sheath - sm extrahaustorial membrane - v vacuole - ve vesicle     

A light and electron microscopic study of stigmas inAneilema andCommelina species (Commelinaceae)

Summary The stigmas of species inAneilema andCommelina are trifid and comprise elongate papillae. Progressive degeneration of papular cells is observed in stigmas from open flowers and at anthesis papillae may be moribund and collapsed. Fluid emanating from the hollow style flows onto the surface through ruptures in the cuticle at the interpapillar junctions into the interstices at maturity. This secretion stains positively for protein. Stigmas are of the wet type.The cuticle overlying the papillar cells is ridged and at the final stages prior to flowering this cuticle becomes detached from the underlying cellulosic wall. The sub-cuticular space so formed is filled with secretion. InAneilema species detachment of cuticle is at the papillar tip and along the lateral walls. InCommelina species the anticlinal walls of adjacent papillae are strongly attached for much of their length and thus detachment of cuticle is restricted to the papillar tip. The cell wall at the tip in both genera may proliferate forming a rudimentary transfer-cell type wall. The secretion is considered to be produced by the papillar cells. It is PAS positive but fails to stain for protein and in both the light and electron microscopes appears heterogenous.Pollen attachment, hydration, germination and early tube growth are very rapid following self-pollination, the pollen tubes entering the neck of the style within ten minutes of attachment.A unique character combination involving pollen and stigmas in these genera indicates a monophyletic origin.     

大鼠舌乳头酶组织化学及扫描电镜的研究

实验采用酶组织化学法和扫描电镜对大鼠舌乳头的酶活性及其表面结构进行了观测。结果表明。大、鼠舌菌状乳头和轮廓乳头的味蕾处Mg^2 -ATPase为强阳性反应（ ）,ChEase为中等阳性反应（ ）,使用ChE Ag^ 染色方法显示。味蕾含有丰富的神经末梢,结果提示ATP可能是味觉传导中神经递质或调质。     

Denver Papillae Protocol for Objective Analysis of Fungiform Papillae

The goal of the Denver Papillae Protocol is to use a dichotomous key to define and prioritize the characteristics of fungiform papillae (FP) to ensure consistent scoring between scorers. This protocol builds off of a need that has arisen from the last two decades of taste research using FP as a proxy for taste pore density. FP density has historically been analyzed using Miller & Reedy’s 1990 characterizations of their morphology: round, stained lighter, large, and elevated. In this work, the authors forewarned that stricter definitions of FP morphology needed to be outlined. Despite this call to action, follow up literature has been scarce, with most studies continuing to cite Miller & Reedy’s original work. Consequently, FP density reports have been highly variable and, combined with small sample sizes, may contribute to the discrepant conclusions on the role of FP in taste sensitivity. The Genetics of Taste Lab explored this apparent inconsistency in counting and found that scorers were individually prioritizing the importance of these characteristics differently and had no guidance for when a papilla had some, but not all, of the reported qualities of FP. The result of this subjectivity is highly variable FP counts of the same tongue image. The Denver Papillae Protocol has been developed to remedy this consequence through use of a dichotomous key that further defines and prioritizes the importance of the characteristics put forth by Miller & Reedy. The proposed method could help create a standard way to quantify FP for researchers in the field of taste and nutritional studies.     

稻属三种植物叶片下表皮的形态比较

稻属有20多种,其中3种和其他物种明显不同.Oryza eichingeri被认为在亚洲和非洲间断分布;O. officinalis和O punctata被证明同时含有二倍体和四倍体.为了识别种内微形态差异,利用光镜和扫描电镜,对这3个物种的成熟叶片下表皮进行了观察.结果表明,O. eichingeri的叶脉长细胞乳突形状在种内是不一致的,除了斯里兰卡地理宗具有的瘤状乳突外,乌千达地理宗还具有长条状的乳突;同样,种内多样性也存在于O. officinalis和O.punctata内,特别存在于它们不同倍性的细胞型间.在D officinalis中,四倍体有粒状气孔器外围乳突和脉带表皮毛较少,二倍体细胞型具有三角形拱状排列的气孔器外围乳突和较密集的脉带表皮毛;而在O. punctata中,和四倍体相比,二倍体具有小的长细胞表面乳突和低密度分布的气孔.这些稳定的差异为3种植物的种内鉴定和分类修订提供了新的证据.     

Butyric acid stimulates rumen mucosa development in the calf mainly by a reduction of apoptosis

In ruminants the Stimulation of papillar growth by butyric acid is well described but effects on mitosis and apoptosis are not known. To clarify the effect of short chain fatty acids three groups of three calves received a basic ration of 100 g hay per day for 6 weeks and additionally milk replacer. From these, two groups were fed with increasing amounts of the salts of either propionic acid (53 to 390 g) or butyric acid up to (54 to 326 g). The control group instead received an additional isocaloric amount of milk replacer. Mitosis was characterized by Ki67 immunoreactivity, apoptosis by a modified TUNEL assay and by electron microscopy. The feeding regimes led to significant differences of papillar length, increasing from 1.0mm (controls) to 2.2 mm (propionic acid) and 4 mm (butyric acid). This enlargement was partly explained by an increased mitotic rate for the two fatty acid groups. The difference between the fatty acid groups was mainly explained by different apoptotic rates which were only one third for butyric acid compared to propionic acid (P < 0.001). In conclusion, butyric acid is a specific inhibitor of ruminal apoptosis in vivo.     

Mycoparasitic relationships

The mode of attack and the infection structures of the necrotrophic mycoparasite, Pythium acanthicum, as well as the responses of various fungal hosts to parasitism were studied using both electron and light microscopy. Many taxonomically distinct fungal hosts were used, though Phycomyces blakesleeanus, Pythium aphanidermatum, Rhizoctonia solani and a basidiomycete identified as Corticium sensu lato were studied in greatest detail. Parasitism was by direct penetration of the fungal host without appressorium formation by the parasite. The host's cells responded to contact by P. acanthicum by forming papillae. The morphological features of the papillae varied with the particular host. In P. blakesleeanus they were comprised of vesicles and segments of cytoplasm entrapped in a fibrillo-granular matrix, while in R. solani and the Corticium basidiomycete they contained considerable amounts of electron-opaque and electron-translucent material. Evidence for both mechanical and enzymatic penetration of the host fungi by the parasite are presented. Details of host wall and septum penetration by the parasite are presented using time-lapse light microscopy with in vivo systems. Many of these stages of parasitism were examined ultrastructurally. Some comparisons of these mycoparasitic relationships are discussed in relation to what is known from the literature about phytoparasitic interactions.     

Transgressive segregation for very low and high levels of basal resistance to powdery mildew in barley

Basal resistance of barley to powdery mildew is a quantitatively inherited trait that limits the growth and sporulation of barley powdery mildew pathogen by a non-hypersensitive mechanism of defense. Two experimental barley lines were developed with a very high (ErBgh) and low (EsBgh) level of basal resistance to powdery mildew by cycles of convergent crossing and phenotypic selection between the most resistant and between the most susceptible lines, respectively, from four mapping populations of barley. Phenotypic selection in convergent crossing was highly effective in producing contrasting phenotypes for basal resistance and susceptibility. In ErBgh, almost 90% of infection units failed to form a primary haustorium in the epidermal cells in association with papilla formation, but in EsBgh only 33% of infection units failed to form a primary haustorium. The contrast between ErBgh and EsBgh for successful formation of secondary and subsequent haustoria was much less obvious (69% versus 79% successful secondary haustorium formation). In an earlier investigation, we determined seven QTLs for basal resistance in the four mapping populations. Checking the peak markers of these QTLs indicated that only four out of seven QTLs were confirmed to be present in the selected resistant lines and only four QTLs for susceptibility were confirmed to be present in the selected susceptible lines. Surprisingly, none of the expected QTLs could be detected in the resistant line ErBgh. We discuss some reasons why marker aided selection might be less efficient in raising levels of basal resistance than phenotypic selection. The very resistant and susceptible lines developed here are valuable material to be used in further experiments to characterize the molecular basis of basal resistance to powdery mildew.     

Caenorhabditis elegans: localization of cholinesterase associated with anterior nematode structures.

By employing a histochemical procedure on adult nematodes, the base of the Caenorhabditis elegans amphid appears to contain acetylcholinesterase and a nonspecific cholinesterase. Some precipitation was observed in the kinetosome region of the inner labial papilla with acethylthiocholine (AtCh) as substrate but not, in limited observations, in the absence of substrate or with butyrylthiocholine (BtCh). The amphidial tips, the tips of the inner labial papillae, and the lining of the buccal cavity contained substantial reaction product at the ultrastructural level, with or without substrates and inhibitors and therefore cannot be related to the presence of a cholinesterase.