Identification of small non-coding RNAs in the planarian Dugesia japonica via deep sequencing

Freshwater planarian flatworm possesses an extraordinary ability to regenerate lost body parts after amputation; it is perfect organism model in regeneration and stem cell biology. Recently, small RNAs have been an increasing concern and studied in many aspects, including regeneration and stem cell biology, among others. In the current study, the large-scale cloning and sequencing of sRNAs from the intact and regenerative planarian Dugesia japonica are reported. Sequence analysis shows that sRNAs between 18nt and 40nt are mainly microRNAs and piRNAs. In addition, 209 conserved miRNAs and 12 novel miRNAs are identified. Especially, a better screening target method, negative-correlation relationship of miRNAs and mRNA, is adopted to improve target prediction accuracy. Similar to miRNAs, a diverse population of piRNAs and changes in the two samples are also listed. The present study is the first to report on the important role of sRNAs during planarian Dugesia japonica regeneration.     

Pediatric grand rounds: a tribute to Norman J. Siegel, M.D

At ceremonies held in Baltimore Maryland on May, 4, 2002, Dr. Howard A Pearson, Professor of Pediatrics, was awarded the John A. Howland award of the American Pediatric Society, probably the most prestigious award of American Pediatrics. Dr. Pearson had been nominated for the award by Dr. Norman Siegel. The Department of Pediatrics Grand Rounds on Wednesday noon, October 26, 2002 was originally scheduled as a repetition of the presentation by Dr. Siegel and the acceptance by Dr. Pearson for those who could not be in Baltimore. However; in a number of meetings, unknown to Dr. Siegel, it was unanimously decided that it would be very appropriate to instead honor him as he stepped down from his position as Vice- and Interim Chairman of Pediatrics, and to formally thank him for his long and faithful service to the Department of Pediatrics, the Yale University School of Medicine, and the Yale New Haven Hospital.     

From structure to solutions: the role of basic research in developing anthrax countermeasures: Microbiology Graduate Program Seminar: Anthrax toxin

Dr. John Collier traced the discoveries that elucidated the structure and function of the anthrax toxin in his talk "Anthrax Toxin," which was part of the Microbiology Graduate Program Seminar Series at Yale School of Medicine on February 23, 2012. Dr. Collier, Professor of Microbiology and Immunobiology at Harvard University, began by noting the advantages to studying anthrax pathogenesis in a biosafety level-1 lab. This designation does not merely facilitate his research, but also reflects a larger trend of basic research being leveraged to develop translational applications. Basic research on toxin structure has led to the development of a vaccine by Dr. Collier's group. Next-generation prophylactics also may stem from recent discoveries uncovering a role for cellular cofactors that mediate toxin function. Finally, basic research into the toxin substructure has facilitated efforts to change the receptor tropism to target dysregulated cells for therapeutic purposes. The urgency around biodefense agents makes the choice of research priorities a salient issue. As such, this author submits that basic research occupies a unique and lucrative niche driving clinical applications.     

Four Children and Yale: The Making of a Human Geneticist: The Grover Powers Lecture 2014

Dr. Leon E. Rosenberg delivered the following presentation as the Grover Powers Lecturer on May 14, 2014, which served as the focal point of his return to his “adult home” as a Visiting Professor in the Department of Pediatrics. Grover F. Powers, MD, was one of the most influential figures in American Pediatrics and certainly the leader who created the modern Department of Pediatrics at Yale when he was recruited in 1921 from Johns Hopkins and then served as its second chairman from 1927 to 1951. Dr. Powers was an astute clinician and compassionate physician and fostered and shaped the careers of countless professors, chairs, and outstanding pediatricians throughout the country. This lectureship has continued yearly since it first honored Dr. Powers in 1956. The selection of Dr. Rosenberg for this honor recognizes his seminal role at Yale and throughout the world in the fostering and cultivating of the field of human genetics. Dr. Rosenberg served as the inaugural Chief of a joint Division of Medical Genetics in the Departments of Pediatrics and Internal Medicine; he became Chair when this attained Departmental status. Then he served as Dean of the Medical School from 1984 to 1991, before he became President of the Pharmaceutical Research Institute at Bristol-Myers Squibb and later Senior Molecular Biologist and Professor at Princeton University, until his recent retirement. Dr. Rosenberg has received numerous honors that include the Borden Award from the American Academy of Pediatrics, the McKusick Leadership Award from the American Society for Human Genetics, and election to the Institute of Medicine and the National Academy of Sciences.     

LIN28调控哺乳动物干细胞和生殖细胞发育分化的研究概述

Lin28为一种保守的RNA结合蛋白质,在细胞代谢、细胞周期和多能性维持中具有重要调控作用。近年来,发现Lin28在哺乳动物原始生殖细胞形成和分化、精原干细胞的形成、自我更新和分化调控中具有不可替代的作用。本文对Lin28作用及其对哺乳动物干细胞和生殖细胞发育分化影响的研究进展作一简述。     

Jordan Raff

Jordan Raff is a Cancer Research UK funded group leader at the Wellcome/CR-UK Gurdon Institute in Cambridge, England. He obtained his PhD from the Department of Biochemistry at Imperial College, London, and he worked as a Post-doctoral fellow at the Department of Biophysics and Biochemistry, University of California, San Francisco. He is currently a Director of the Company of Biologists, and on the committee of the British Society of Cell Biology. He has studied centrosomes and cell division in fruit flies throughout his scientific career.     

果蝇肠道干细胞研究进展

对果蝇Drosophila melanogaster Meigen肠道干细胞的研究现已触及生物学的很多方面,目前对这类细胞的研究主要集中于干细胞的小生境、信号路径的调控和细胞的分化,本文阐述了果蝇肠道干细胞研究方面的最新进展。果蝇肠道干细胞和脊椎动物肠道干细胞有诸多类似之处,所以弄清果蝇肠道干细胞的机理,可以为复杂的脊椎动物肠道干细胞研究提供了一定的理论基础。     

New insights into germ cell tumor formation.

Recent years have witnessed a number of new findings with significant implications for our understanding of the development of germ cell tumors. This communication reviews some of these recent insights with an emphasis on mechanisms that may convert a germ cell into a tumor cell. Three aspects are discussed in this review: (1) the early origin of germ cell tumors from primordial germ cells through an aberrant mitosis-to-meiosis switch; (2) errors during meiosis, which promote tumorigenic transformation of germ cells; and (3) the role of small RNAs such as oncomirs (miRNAs) and oncopirs (piRNAs) in germ cell tumor formation. Since much has been learned using a variety of organismal models, data obtained in experiments with mice, nematodes, fruit flies, and human data will be considered. Only exemplary references are included.     

Critical role of Lin28‐TNFR2 signalling in cardiac stem cell activation and differentiation

Tumour necrotic factor receptor‐2 (TNFR2) has been to be cardiac‐protective and is expressed in cardiac progenitor cells. Our goal is to define the mechanism for TNFR2‐mediated cardiac stem cell activation and differentiation. By employing a protocol of in vitro cardiac stem cell (CSC) differentiation from human inducible pluripotent stem cell (hiPSC), we show that expression of TNFR2 precedes expression of CSC markers followed by expression of mature cardiomyocyte proteins. Activation of TNFR2 by a specific agonist promotes whereas inhibition of TNFR2 by neutralizing antibody diminishes hiPSC‐based CSC differentiation. Interestingly, pluripotent cell factor RNA‐binding protein Lin28 enhances TNFR2 protein expression in early CSC activation by directly binding to a conserved Lin28‐motif within the 3'UTR of Tnfr2 mRNA. Furthermore, inhibition of Lin28 blunts TNFR2 expression and TNFR2‐dependent CSC activation and differentiation. Our study demonstrates a critical role of Lin28‐TNFR2 axis in CSC activation and survival, providing a novel strategy to enhance stem cell‐based therapy for the ischaemic heart diseases.     

Discovery of piRNAs Pathway Associated with Early-Stage Spermatogenesis in Chicken

Piwi-interacting RNAs (piRNAs) play a key role in spermatogenesis. Here, we describe the piRNAs profiling of primordial germ cells (PGCs), spermatogonial stem cells (SSCs), and the spermatogonium (Sp) during early-stage spermatogenesis in chicken. We obtained 31,361,989 reads from PGCs, 31,757,666 reads from SSCs, and 46,448,327 reads from Sp cells. The length distribution of piRNAs in the three samples showed peaks at 33 nt. The resulting genes were subsequently annotated against the Gene Ontology (GO) database. Five genes (RPL7A, HSPA8, Pum1, CPXM2, and PRKCA) were found to be involved in cellular processes. Interactive pathway analysis (IPA) further revealed three important pathways in early-stage spermatogenesis including the FGF, Wnt, and EGF receptor signaling pathways. The gene Pum1 was found to promote germline stem cell proliferation, but it also plays a role in spermatogenesis. In conclusion, we revealed characteristics of piRNAs during early spermatogonial development in chicken and provided the basis for future research.     

Piwis and piwi-interacting RNAs in the epigenetics of cancer

An increasing body of evidence suggests that cancer cells acquire "stem-like" epigenetic and signaling characteristics during the tumorigenic process, including global DNA hypo-methylation, gene-specific DNA hyper-methylation, and small RNA deregulation. RNAs have been known to be epigenetic regulators, both in stem cells and in differentiated cells. A novel class of small RNAs, called piwi-interacting RNAs (piRNAs), maintains genome integrity by epigenetically silencing transposons via DNA methylation, especially in germline stem cells. piRNAs interact exclusively with the Piwi family of proteins. The human Piwi ortholog, Hiwi, has been found to be aberrantly expressed in a variety of human cancers and in some, its expression correlates with poor clinical prognosis. However, there has been little investigation into the potential role that Piwi and piRNAs might play in contributing to the "stem-like" epigenetic state of a cancer. This review will highlight the current evidence supporting the importance of Piwi and piRNAs in the epigenetics of cancer and provide a potential model for the role of Piwi and piRNAs in tumorigenesis.     

Detection of embryonic stem cell lysate biomarkers by surface plasmon resonance with reduced nonspecific adsorption

Surface plasmon resonance imaging (SPRi) has emerged as a versatile biosensor to detect a wide range of biomolecular interactions with divergent potential applications. However, the use of this advanced-level technology for stem cell lysate study is still not much explored. Cell lysates are significant biological analytes used for disease diagnostics and proteomic studies, but their complex nature limits their use as an analyte for SPRi biosensors. Here, we review the problems associated with the use of SPRi for stem cell lysate study and examine the role of surface chemistry, running buffer, and blocking solution in order to minimize nonspecific adsorption (NSA). We detect the expression of Oct4, Sox2, Nanog, Rex1, and Lin28 biomarkers present in mouse embryonic stem cell (mESC) lysate against their corresponding antibodies immobilized on the sensor surface with reduced NSA. The current study shows that the conjunction of SPRi and microarray can be used as a label-free, high-throughput, and rapid technique for detection of biomarkers and their relative abundance in stem cell lysate study.     

LIS1 and spindle orientation in neuroepithelial cells

Asymmetric stem cell division is thought to require precise orientation of the mitotic spindle. However, a recent study in Cell (Yingling et al., 2008) analyzes the role of LIS1 in the developing mouse brain and shows that spindle orientation is more important during early, symmetric progenitor cell divisions than for later asymmetric divisions.     

Disentangling the link between leaf photosynthesis and turgor in fruit growth

Despite the importance of understanding plant growth, the mechanisms underlying how plant and fruit growth declines during drought remain poorly understood. Specifically, it remains unresolved whether carbon or water factors are responsible for limiting growth as drought progresses. We examine questions regarding the relative importance of water and carbon to fruit growth depending on the water deficit level and the fruit growth stage by measuring fruit diameter, leaf photosynthesis, and a proxy of cell turgor in olive (Olea europaea). Flow cytometry was also applied to determine the fruit cell division stage. We found that photosynthesis and turgor were related to fruit growth; specifically, the relative importance of photosynthesis was higher during periods of more intense cell division, while turgor had higher relative importance in periods where cell division comes close to ceasing and fruit growth is dependent mainly on cell expansion. This pattern was found regardless of the water deficit level, although turgor and growth ceased at more similar values of leaf water potential than photosynthesis. Cell division occurred even when fruit growth seemed to stop under water deficit conditions, which likely helped fruits to grow disproportionately when trees were hydrated again, compensating for periods with low turgor. As a result, the final fruit size was not severely penalized. We conclude that carbon and water processes are able to explain fruit growth, with importance placed on the combination of cell division and expansion. However, the major limitation to growth is turgor, which adds evidence to the sink limitation hypothesis.     

piRNA‐63076 contributes to pulmonary arterial smooth muscle cell proliferation through acyl‐CoA dehydrogenase

Piwi‐interacting RNAs (piRNAs) are thought to be germline‐specific and to be involved in maintaining genome stability during development. Recently, piRNA expression has been identified in somatic cells in diverse organisms. However, the roles of piRNAs in pulmonary arterial smooth muscle cell (PASMC) proliferation and the molecular mechanism underlying the hypoxia‐regulated pathological process of pulmonary hypertension are not well understood. Using hypoxic animal models, cell and molecular biology, we obtained the first evidence that the expression of piRNA‐63076 was up‐regulated in hypoxia and was positively correlated with cell proliferation. Subsequently, we showed that acyl‐CoA dehydrogenase (Acadm), which is negatively regulated by piRNA‐63076 and interacts with Piwi proteins, was involved in hypoxic PASMC proliferation. Finally, Acadm inhibition under hypoxia was partly attributed to DNA methylation of the Acadm promoter region mediated by piRNA‐63076. Overall, these findings represent invaluable resources for better understanding the role of epigenetics in pulmonary hypertension associated with piRNAs.     

Cell division and cell enlargement in fruit of Lagenaria leucantha as influenced by pollination and plant growth substances

The effects of NAA (naphthaleneacetic acid), GA₃ (gibberellic acid), CPPU (N-(2-chloro-4-pyridyl)-N'-phenylurea) and pollination on fruit set, cell division and enlargement were studied in Lagenaria leucantha, an important vegetable. NAA and GA₃ were ineffective in inducing parthenocarpy, whereas CPPU induced parthenocarpic fruit significantly larger than fruit that resulted from pollination. Cell division, which occurred during the first 4 days after pollination was not reactivated by NAA or GA₃, but was effectively reactivated by CPPU. The cell number of the total cross-section of CPPU-treated fruit was 117.4% of that of pollinated fruit and 154.4% of that of unpollinated at 12 DAA (days after anthesis) respectively. The CPPU-induced parthenocarpic fruit had the largest cell cross-sectional area followed, successively, by pollinated fruit, NAA-treated fruit, GA₃-treated fruit and unpollinated fruit. These results indicate that CPPU induced parthenocarpic fruit growth by directly reactivating cell division and expansion.     

Comparing plant and animal extracellular matrix-cytoskeleton connections — are they alike?

Summary Cell adhesion and communication is one of the most fascinating fields of modern biology. How do cells receive information from the environment and from neighboring cells? How does this information elicit morphogenesis, cell division and migration? The recent identification of the surface molecules involved in these events in animal systems is beginning to disclose that a continuum, extracellular matrix-plasma membrane-cytoskeleton, may be a common structure present in all eukaryotic cells. In this article we compare current knowledge on this complex structure in animal systems to the emerging data on plants. We point out the areas that need additional research to fully understand the role of the cell wall-cytoskeleton continuum in plants.Abbreviations ABP actin-binding protein - AGP arabinogalactan proteins - CTK cytoskeleton - ECM extracellular matrix - FN fibronectin - hFN human fibronectin - HRGP hydroxyproline-rich glycoproteins - hVN human vitronectin - PM plasma membrane - SAM substrate adhesion molecule - VN vitronectin Dedicated to Professor Dr. Hartmut K. Lichtenthaler on the occasion of his 60th birthday     

Ultrastructure of transmitting tissue of Lycopersicon peruvianum style: Development and histochemistry

Summary The development of the transmitting tissue of the style of Lycopersicon peruvianum goes, after the completion of cell division and cell wall formation, through two distinct phases. During the first phase, the cells enlarge and the main part of the intercellular substance, consisting of pectins, is formed. During the second phase, the cells form an extensive rough endoplasmic reticulum (RER) and proteins are incorporated in the intercellular substance. A possible role of these proteins in the incompatibility reaction is proposed.Dr. M. Cresti has completed this research during his stay in Wageningen at the Botanical Department where he was a fellow of that Agricultural University