Contributions of scanning electron microscopy to corneal pathology

The increasing use of scanning electron microscopy in pathology has provided new avenues of observation and evaluation for the pathologist and researcher. The cell surface changes noted by scanning electron microscopy can contribute to an overall understanding of the pathoanatomy and pathophysiology of disease states when correlated with light microscopy and transmission electron microscopy. Our laboratory routinely evaluates corneal pathology specimens by correlative light, transmission and scanning electron microscopy. This procedure has provided new and in some cases previously undocumented corneal pathologic surface morphology of epithelial downgrowth, experimental epithelial-endothelial interactions and ichthyosiform erythroderma.     

Contributions of plant molecular systematics to studies of molecular evolution

Dobzhansky stated that nothing in biology makes sense except in the light of evolution. A close corollary, and the central theme of this paper, is that everything makes a lot more sense in the light of phylogeny. Systematics is in the midst of a renaissance, heralded by the widespread application of new analytical approaches and the introduction of molecular techniques. Molecular phylogenetic analyses are now commonplace, and they have provided unparalleled insights into relationships at all levels of plant phylogeny. At deep levels, molecular studies have revealed that charophyte green algae are the closest relatives of the land plants and suggested that liverworts are sister to all other extant land plants. Other studies have suggested that lycopods are sister to all other vascular plants and clarified relationships among the ferns. The impact of molecular phylogenetics on the angiosperms has been particularly dramatic – some of the largest phylogenetic analyses yet conducted have involved the angiosperms. Inferences from three genes (rbcL, atpB, 18S rDNA) agree in the major features of angiosperm phylogeny and have resulted in a reclassification of the angiosperms. This ordinal-level reclassification is perhaps the most dramatic and important change in higher-level angiosperm taxonomy in the past 200 years. At lower taxonomic levels, phylogenetic analyses have revealed the closest relatives of many crops and model organisms for studies of molecular genetics, concomitantly pointing to possible relatives for use in comparative studies and plant breeding. Furthermore, phylogenetic information has contributed to new perspectives on the evolution of polyploid genomes. The phylogenetic trees now available at all levels of the taxonomic hierarchy for angiosperms and other green plants should play a pivotal role in comparative studies in diverse fields from ecology to molecular evolution and comparative genetics.     

采用分子生物学技术诊断隐球菌脑膜脑炎的研究

目的采用分子检测技术对疑似隐球菌感染的脑膜炎病例进行诊断。方法收集患者的脑脊液样本,提取DNA,设计引物进行PCR扩增,采用DNA芯片技术对扩增产物进行分子检测。结果显示样本新生隐球菌阳性。结论通过ITS保守序列设计引物进行PCR扩增和DNA芯片技术对常规真菌学检查不能确定的疑似隐球菌脑膜炎患者脑脊液样本进行非培养检测,具有实验室诊断参考价值。     

Contributions of fluorescence techniques to understanding G protein-coupled receptor dimerisation

G protein-coupled receptors (GPCRs) are the largest class of eukaryotic cell-surface receptors and, over the last decade, it has become clear that they are capable of dimerisation. Whilst many biochemical and biophysical approaches have been used to study dimerisation, fluorescence techniques, including Förster resonance energy transfer and single molecule fluorescence, have been key players. Here we review recent contributions of fluorescence techniques to investigate GPCR dimers, including dimerisation in cell membranes and native tissues, the effect of ligand binding on dimerisation and the kinetics of dimer formation and dissociation. The challenges of studying multicomponent membrane protein systems have led to the development and refinement of many fluorescence assays, allowing the functional consequences of receptor dimerisation to be investigated and individual protein molecules to be imaged in the membranes of living cells. It is likely that the fluorescence techniques described here will be of use for investigating many other multicomponent membrane protein systems.     

分子生物学技术在双翅目实蝇科昆虫系统发育研究中的应用

分子生物学技术如同工酶电泳、RFLP、RAPD、核酸序列分析、微卫星DNA和探针杂交等,在实蝇科昆虫系统发育研究中具有重要作用。利用这些技术对实蝇种群进行系统发育研究,揭示其亲缘及进化关系,从生命本质上寻找实蝇种群间的内在联系。文章综述上述几种分子生物学技术在实蝇科昆虫核酸结构、种内和种间的亲缘及进化关系等方面的研究进展,分析在应用中存在的问题,展望这些分子生物学技术在实蝇科昆虫系统发育中的应用前景。     

Contributions of a modified electrodynamics to the molecular biochirality

In this paper, we investigate the physical basis behind the molecular biochirality from the computation of a parity violation energy difference (PVED) in enantiomers of organic molecules (e.g., amino acids, which occur as levogyrous-type in nature), by considering the influence of fundamental interactions beyond the standard model of elementary particles and interactions. Particularly, we study the role of a 4-D Chern‑Simons theory at the origin of this PVED, the Carroll‑Field‑Jackiw electrodynamics, which violates both Lorentz and parity symmetries. Then, we consider terrestrial and Jovian scenarios where the influence of a modified (effective) magnetic field generated by the planets on the molecules is taken into account in the calculation of PVED. Besides this quantity, we also calculate the relative quantity excess of an enantiomer over the other in a thermal bath. Finally, we compare the obtained results with those ones from other models based on fundamental interactions.     

Histological and immunohistochemical studies of the endocrine pancreas of lizards

The endocrine pancreas of the grass lizard, Mabuya quinquetaenia-ta, and of the desert lizard, Uromastyx aegyptia, was investigated histologically and immunohistochemically. In both lizard species four cell types were observed in the endocrine pancreas, namely insulin (B), glucagon (A), somatostatin (D) and pancreatic polypeptide (PP) cells. In both species in B, A and D cells could be detected by their cross-reactivity with antisera raised against mammalian insulin, glucagon and somatostatin. However, these cells showed different tinctorial propertis in the two lizard species. In both species the endocrine tissues were concentrated in the splenic lobe of the pancreas. In the grass lizard the endocrine tissue in the splenic lobe of consisted mainly of B, A and D cells and in the ventral lobe the major cell types were PP and D cells. In the desert lizard, on the other hand, the frequency and the pattern of orientation of B, A and D cells were the same in both the splenic and the ventral lobes, but PP cells in the ventral lobe outnumbered those of the splenic lobe. The PP and D cells scattered in the exocrine parenchyma and the long protrusions which they exhibited suggested that these cell exerted paracrine control on the acinar cells. It is speculated that this control by PP cells may be trophic and by D cells inhibitory.     

Histological and immunohistochemical studies of the endocrine pancreas of lizards

Summary The endocrine pancreas of the grass lizard, Mabuya quinquetaeniata, and of the desert lizard, Uromastyx aegyptia, was investigated histologically and immunohistochemically. In both lizard species four cell types were observed in the endocrine pancreas, namely insulin (B), glucagon (A), somatostatin (D) and pancreatic polyeptide (PP) cells. In both species the B, A and D cells could be detected by their cross-reactivity with antisera raised against mammalian insulin, glucagon and somatostatin. However, these cells showed different tinctorial properties in the two lizard species. In both species the endocrine tissues were concentrated in the splenic lobe of the pancreas. In the grass lizard the endocrine tissue in the splenic lobe consisted mainly of B, A and D cells and in the ventral lobe the major cell types were PP and D cells. In the desert lizard, on the other hand, the frequency and the pattern of orientation of B, A and D cells were the same in both the splenic and the ventral lobes, but PP cells in the ventral lobe outnumbered those of the splenic lobe. The PP and D cells scattered in the exocrine parenchyma and the long protrusions which they exhibited suggested that these cells exerted paracrine control on the acinar cells. It is speculated that this control by PP cells may be trophic and by D cells inhibitory.     

Spontaneous pathology of the baboon endocrine system

Background  Study of endocrine pathology in animal models is critical to understanding endocrine pathology in humans.
Methods  We evaluated 434 endocrine-related diagnoses from 4619 baboon necropsies, established the incidence of spontaneous endocrine pathology, and analyzed the clinical and biochemical data associated with the individual cases.
Results  The most common diagnoses in descending order, were pancreatic islet cell amyloidosis (n = 259), ovarian cysts (n = 50), pituitary adenoma (n = 37), pancreatic islet cell adenoma (n = 20), granulosa cell tumor (n = 15), thyroid adenoma (n = 11), adrenal hyperplasia (n = 10), thyroid carcinoma (n = 8), and pheochromocytoma (n = 6). The incidence of pancreatic islet cell amyloidosis progressively increased with age. Pheochromocytomas were associated with renal and heart failure. The incidence of pancreatic islet cell amyloidosis and adrenal pathology was similar to humans; the incidence of pituitary adenoma and thyroid pathology was lower than in humans.
Conclusions  Endocrine disease in baboons is common and shares clinical and biochemical characteristics with endocrine disease in humans.     

Ovary genes and molecular pathology

In the ovary, primordial follicles have to pass different stages in order to become preovulatory follicles. In the past few years, new genes and therefore new proteins have been recognized as major players in folliculogenesis. Atm, kit ligand and its receptor c-kit are necessary for the maintenance of ovarian follicle pool. GDF-9, BMP15, originating from the oocyte play a major role in early folliculogenesis. Pro and antiapoptotic proteins such as Bax and Bcl2 complete in granulosa cells, in order to maintain or not the follicle alive. FSH receptor is necessary for final follicular maturation, from the preantral stage and beyond. LH receptor is necessary for follicle ovulation. However, new genes and their regulation need to be identified as many ovarian diseases such as premature ovarian failure are not yet clarified.     

Contributions of molecular studies to the phylogeny and systematics of African birds

Helbig, A.J. 2000. Contributions of molecular studies to the phylogeny and systematics of African birds. Ostrich 71 (1 & 2): 40.

Recent advances in DNA technology allow us to study the phylogenetic relationships of birds from a completely new perspective and to base avian systematics on a more solid foundation. In the present paper, relationships of selected groups of birds (birds of prey, Sylviid warblers) will be analysed based on extensive nucleotide sequences of the mitochondrial cytochrome b gene. DNA was isolated from blood, amplified via polymerase chain reaction (PCR) and sequenced directly. Main findings include the following: (1) Old World vultures are polyphyletic with Neophron and Gypaetus being more primitive than the other species. (2) The primitive position of Pandion is confirmed. (3) Aquila rapax and, A. nipalensis are differentiated at species level. (4) Genetic differentiation is substantial in the kestrel complex (Falco tinnunculus, rupicoloides, naumanni), but only slight in the peregrine group (E p. peregrinus, brookei, minor, pelegrinoides). Sylviidae: (5) The genus Sylvia is paraphyletic relative to Parisoma, the latter is in itself not a monophylum and should be merged with Sylvia. (6) Acrocephalus griseldis is genetically a highly distinctive species; A. baeticatus is very similar to A. scirpaceus. Large and small-bodied species groups of reed warblers are each monophyletic. (7) Eastern and western forms of Hippolaispallida are strongly differentiated, probably demanding species status for each. (8) African “Seicercus” are members of the Phylloscopus radiation and probably derive from Asian rather than West Palearctic ancestors. (9) Cisticola and Prinia appear to be sister genera, Camaroptera is closer to these than to Palearctic genera. DNA studies are revolutionising avian systematics by providing easily comparable and highly reproducible information at all taxonomic levels: from within-species differentiation to higher level phylogeny. Mitochondrial DNA is also a suitable marker to study gene flow in hybrid zones and thus establish or refute biological species status of taxa in secondary contact.     

Histochemical and immunohistochemical identification of endocrine cells in the internal ear

The authors describe the results of the study of rabbit decalcified temporal bones and guinea-pig membranous cochlea treated according to the Grimelius argyrophil method and immunohistochemical technique with the use of a number of specific antisera. The study revealed the cells of the diffuse endocrine system (APUD system) in various parts of the internal ear: in the main membrane, receptor elements of the spiral chorda, and spiral ligament. Serotonin and melatonin were identified in the cells of the APUD system. The data obtained may form a theoretical basis of a basically new trend in the study of the function of the internal ear in health and disease.