Small RNAs of Sequoia sempervirens during rejuvenation and phase change.

In this work, the population of small RNAs (sRNAs) was studied in the gymnosperm Sequoia sempervirens during phase changes, specifically in the juvenile, adult and rejuvenated plants obtained in vitro. The potential target genes of Sequoia sRNAs were predicted through bioinformatics. Rejuvenation is a pivotal process in woody plants that enables them to regain their growth potential, which results in the recovery of physiologic and molecular characteristics that were lost when the juveniles mature into adult plants. The results from the five repeated graftings of juvenile, adult and rejuvenated plants in vitro showed that sRNAs could be classified into structural RNAs (Group I), small interfering RNAs (Group II), annotated microRNAs (Group III, and unannotated sRNAs (Group IV). The results indicate that only 573 among 15,485,415 sRNAs (Groups III and IV) had significantly different expression patterns associated with rejuvenation and phase change. A total of 215 sRNAs exhibited up-regulated expression patterns in adult shoots, and 358 sRNAs were down-regulated. Expression profiling and prediction of possible target genes of these unique small RNAs indicate possible functions in the control of photosynthetic efficiency and rooting competence abundance during plant rejuvenation. Moreover, the increase in SsmiR156 and decrease in SsmiR172 during plant rejuvenation suggested that these two microRNAs extensively affect phase transition.

The organization of cytoplasmic ribosomal protein genes in the Arabidopsis genome.

Eukaryotic ribosomes are made of two components, four ribosomal RNAs, and approximately 80 ribosomal proteins (r-proteins). The exact number of r-proteins and r-protein genes in higher plants is not known. The strong conservation in eukaryotic r-protein primary sequence allowed us to use the well-characterized rat (Rattus norvegicus) r-protein set to identify orthologues on the five haploid chromosomes of Arabidopsis. By use of the numerous expressed sequence tag (EST) accessions and the complete genomic sequence of this species, we identified 249 genes (including some pseudogenes) corresponding to 80 (32 small subunit and 48 large subunit) cytoplasmic r-protein types. None of the r-protein genes are single copy and most are encoded by three or four expressed genes, indicative of the internal duplication of the Arabidopsis genome. The r-proteins are distributed throughout the genome. Inspection of genes in the vicinity of r-protein gene family members confirms extensive duplications of large chromosome fragments and sheds light on the evolutionary history of the Arabidopsis genome. Examination of large duplicated regions indicated that a significant fraction of the r-protein genes have been either lost from one of the duplicated fragments or inserted after the initial duplication event. Only 52 r-protein genes lack a matching EST accession, and 19 of these contain incomplete open reading frames, confirming that most genes are expressed. Assessment of cognate EST numbers suggests that r-protein gene family members are differentially expressed.

Adenosine deaminase inhibitors: synthesis and biological evaluation of unsaturated, aromatic, and oxo derivatives of (+)-erythro-9-(2'S-hydroxy-3'R-nonyl)adenine [(+)-EHNA].

The synthesis and biological evaluation of three classes of chain-modified derivatives of (+)-EHNA are described. Among the 5', 6'-unsaturated derivatives, the Z-isomer was the most potent inhibitor of adenosine deaminase (ADA) but 3-fold less active than (+)-EHNA. Several 9-aralkyladenines (ARADs) have been prepared, and their inhibitory activity was determined. A minimum of two carbon atoms separating the aromatic ring from the adenine-bearing carbon (C-3') was found to be essential for ADA activity equal to or slightly greater than that of (+)-EHNA. Finally, replacement of the C-5' carbon with an oxygen resulted in reduced potency.

Searching for information on the Internet using the UMLS and Medical World Search.

Medical World Search is a search engine for medical information on the Internet that distinguishes itself from other search engines by its built-in knowledge of medical terminology through its use of the National Library of Medicine's UMLS and its carefully selected but large database of medical sites. After discussing some of the previous uses of the UMLS for medical information retrieval, we describe the Medical World Search system. In October 1996, Medical World Search became operational on the World Wide Web at http:@www.mwsearch.poly.edu. It has been operating uninterrupted since then. We review our experiences with creating a search engine for medical information on the Internet and using the UMLS in this application. The UMLS has some clear advantages in this application. Some aspects of the UMLS also decrease its usefulness in information retrieval. Medical World Search's usage by medical information seekers is summarized. future directions for research are outlined.

The immunolocalization of basic fibroblast growth factor in the mouse uterus during the initial stages of embryo implantation.

Mammalian embryo implantation involves a series of complex interactions between maternal and embryonic cells. Uterine polypeptide growth factors may play critical roles in these cell interactions. Basic fibroblast growth factor (basic FGF) is a member of a family of growth factors. This growth factor may be potentially important for the process of embryo implantation because it (a) is stored within the extracellular matrix and is thus easily available during embryo invasion, (b) is a potent modulator of cell proliferation and differentiation and (c) stimulates angiogenesis. The immunolocalization of basic FGF in the uterus during the peri-implantation period of pregnancy is presented in this study. Uterine tissue samples were obtained on days 6-9 of pregnancy with day 1 of pregnancy being the day of a vaginal copulatory plug. Uterine samples were fixed in Bouin's fluid for no longer than 18 h. Following fixation and paraffin embedding, sections were exposed to primary antisera made in rabbits against either (a) human recombinant basic FGF or (b) 1-24 synthetic fragment of bovine basic FGF. The primary antibody was followed by biotinylated goat anti-rabbit IgG and a biotin-avidin-peroxidase complex. There were no differences in the immunolocalization of basic FGF using either source of primary antibody. Our results demonstrated both temporal and spatial changes in the localization of immunoreactive basic FGF within the implantation chamber during days 6-9 of pregnancy. Inter-implantation sites resembled the non-pregnant uterus with basic FGF present in extracellular matrices including basal laminae. On day 6 of pregnancy, decidual cells within the primary decidual zone lacked both intracellular and pericellular basic FGF while non-decidualized uterine stroma resembled inter-implantation sites. By days 7-8 of pregnancy, the secondary decidual zone had formed and was characterized by the distinct pericellular localization of basic FGF around individual decidual cells. By day 9 of pregnancy, the mesometrial region was forming and contained cords of decidual cells and a labyrinth of maternal blood vessels. The decidual cells contained diffuse intracellular basic FGF. Trophoblast cells were devoid of basic FGF at all times examined. These results indicate that basic FGF is present within the implantation chamber on days 6-9 of pregnancy and may be involved in the decidual cell response, trophoblast cell invasion and angiogenesis.

Routing of a secretory protein to the endocytic compartment in transfected Madin Darby canine kidney cells.

Transfected Madin Darby canine kidney (MDCK) cells (3A) expressing human growth hormone (hGH) contain twice as many Golgi stacks as untransfected cells. How MDCK cells, lacking a regulated pathway, deal with (over)expression of a protein hormone, or any exogenous protein, has not been examined in detail. Since hGH constituted 10% of total secreted proteins, it was not apparent why Golgi amplification was needed, unless some enters a nonsecretory compartment. Studies were undertaken to determine hGH fate. By using an inhibitor of protein synthesis, or by analyzing pulse labeled immunoprecipitated hGH, 20-30% of hGH was shown to remain intracellular even after 4 h. That portion might be localized in the endosome/lysosome compartment, because it is post-Golgi. Immunoelectron microscopy with antibodies against hGH, clathrin, and cathepsin D demonstrated clathrin and hGH colocalized, as did hGH and cathepsin D. The latter were found in large vesicles, but no hGH appeared in lysosomes, due to its degradation. Analysis of isolated lysosome/endosomes revealed vesicles containing both hGH and cathepsin D, but more containing only cathepsin D. Endocytosis studies suggested the 3A basolateral endosomal compartment may be more capacious than normal. Thus, 3A Golgi amplification resulted in an expanded endosome compartment to accommodate secretory protein (over)expression.

Immunohistochemical localization of basic fibroblast growth factor (bFGF) within growing and atretic mouse ovarian follicles.

Basic fibroblast growth factor is a biologically active peptide with a strong affinity for heparin. This growth factor has been previously shown to be mitogenic for a variety of mesoderm and neuroectoderm-derived cells. The immunohistochemical localization of basic FGF within mouse growing and atretic ovarian follicles is presented in the study. Ovarian tissue samples were obtained either (a) randomly from mice housed in a controlled light environment or (b) following the administration of exogenous gonadotropins to stimulate follicle development. Ovarian samples were fixed in Bouin's fluid for no longer than 18 h. Following fixation and paraffin embedding, sections were exposed to a primary antibody made in rabbits against either (a) human recombinant basic FGF or (b) the 1-24 synthetic fragment of bovine basic FGF. The primary antibody was followed by biotinylated goat anti-rabbit IgG and a biotin-avidin-peroxidase complex. There were no differences in the immunolocalization of basic FGF using either source of primary antibody or between randomly obtained ovarian samples and those obtained from mice given exogenous gonadotropins. Basic FGF was immunolocalized in follicle basal laminae and was also closely associated with individual follicle cells during all stages of ovarian follicle development. Basic FGF was absent in the theca interna, oocyte cytoplasm, zona pellucida and follicle fluid of normal growing follicles. Individual corpora luteal cells were surrounded by basic FGF but lacked cytoplasmic staining. Atretic follicles exhibited staining patterns similar to their respective stage of follicle development. However, when present, follicle fluid within atretic follicles was strongly positive for basic FGF. These results indicate that basic FGF may be an important factor involved in intraovarian control mechanisms.

Immunohistochemical localization of basic fibroblast growth factor within the mouse uterus.

Uterine samples were either rapidly frozen in liquid nitrogen or placed in Bouin's fixative. A commercial primary polyclonal antibody made in rabbits against human recombinant basic fibroblast growth factor (bFGF) was used. Western blot analysis indicated that the antibody was specific for bFGF and did not react with acidic FGF. The primary antibody was followed by either goat anti-rabbit immunoglobulin G (IgG) conjugated to the fluorescent phycobiliprotein tracer phycoerythrin or biotinylated goat anti-rabbit IgG and a biotin-avidin-peroxidase complex. Specificity controls using adjacent sections were carried out by (i) substituting normal rabbit sera for the primary antisera, (ii) omitting the primary antisera or (iii) extracting sections with NaCl (2 mol l-1) prior to the immunochemical procedures. No binding of the antibody was observed with any of the specificity control sections. The connective tissue stroma and the basal lamina associated with uterine glandular and surface epithelial layers were positive for bFGF. Localization was not observed within surface or glandular epithelial cells. The basal lamina and endothelial cells associated with blood vessels within the uterus and the smooth muscle cells of the myometrium were positive for bFGF. There were no differences in uterine localization patterns or intensity during the oestrous cycle or after ovariectomy and steroid hormone supplementation. These studies demonstrate the specific localization of bFGF within the mouse uterus.

Experimental demonstration of a sensing mechanism for optical-fiber intermodal interference sensors.

A series of experiments in which a multimode optical fiber was forced to vibrate by a loudspeaker was performed to investigate the sensing mechanism of an integrated optical-fiber communication-sensing system. It was demonstrated that the sensing mechanism is predominantly pressure-induced phase modulation rather than modecoupling-induced power transfer in an optical fiber.