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Michael H Cortez
A species exhibits a hydra effect when, counter-intuitively, increased mortality of the species causes an increase in its abundance. Hydra effects have been studied in many continuous time (differential equation) multispecies models, but only rarely have hydra effects been observed in or studied with discrete time (difference equation) multispecies models. In addition most discrete time theory focuses on single-species models. Thus, it is unclear what unifying characteristics determine when hydra effects arise in discrete time models...
September 27, 2016: Journal of Theoretical Biology
Marcelo Rodrigues, Thomas Ostermann, Leopold Kremeser, Herbert Lindner, Christian Beisel, Eugene Berezikov, Bert Hobmayer, Peter Ladurner
The differentiated ectodermal basal disc cells of the freshwater cnidarian Hydra secrete proteinaceous glue to temporarily attach themselves to underwater surfaces. Using transcriptome sequencing and a basal disc-specific RNA-seq combined with in situ hybridisation a highly specific set of candidate adhesive genes was identified. A de novo transcriptome assembly of 55,849 transcripts (>200 bp) was generated using paired-end and single reads from Illumina libraries constructed from different polyp conditions...
October 2016: Biofouling
George R Dakwar, Kevin Braeckmans, Wim Ceelen, Stefaan C De Smedt, Katrien Remaut
Delivery of small interfering RNA (siRNA) is recently gaining tremendous attention for the treatment of ovarian cancer. The present study investigated the potential of different liposomal formulations composed of (2,3-dioleoyloxy-propyl)-trimethylammonium (DOTAP) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) encapsulating siRNA (hydration method) for their ability to knockdown luciferase (Luc) activity in human ovarian cancer SKOV-3 cells. Fluorescence single particle tracking (fSPT) and fluorescence correlation spectroscopy (FCS) in human-undiluted ascites fluid obtained from a peritoneal carcinomatosis patient revealed that cationic hydra-lipoplexes (HYDRA-LPXs) and HYDRA-LPXs decorated with stable DSPE-PEG (DSPE HYDRA-LPXs) showed high stability during at least 24 h...
September 8, 2016: Drug Delivery and Translational Research
Chen Huang, Jean-Étienne Rl Morlighem, Hefeng Zhou, Érica P Lima, Paula B Gomes, Jing Cai, Inchio Lou, Carlos D Pérez, Simon Ming Lee, Gandhi Rádis-Baptista
Protopalythoa is a zoanthid that, together with thousands of predominantly marine species, such as hydra, jellyfish, and sea anemones, composes the oldest eumetazoan phylum, i.e., the Cnidaria. Some of these species, such as sea wasps and sea anemones, are highly venomous organisms that can produce deadly toxins for preying, for defense or for territorial disputes. Despite the fact that hundreds of organic and polypeptide toxins have been characterized from sea anemones and jellyfish, practically nothing is known about the toxin repertoire in zoanthids...
October 5, 2016: Genome Biology and Evolution
Marcello Tonelli, Anita Lloyd, Neesh Pannu, Scott Klarenbach, Pietro Ravani, Kailash Jindal, Jennifer MacRae, Larry Unsworth, Braden Manns, Brenda Hemmelgarn
BACKGROUND: Rural-dwelling hemodialysis patients have less frequent contact with nephrologists than urban-dwelling patients, and are known to have higher mortality. We hypothesized that rural-dwelling hemodialysis patients would have more evidence of poorly controlled extracellular fluid volume (ECVF) than otherwise similar urban-dwellers. METHODS: We studied prevalent hemodialysis patients within a single renal program in Alberta, Canada and assessed ECFV using bioimpedance spectroscopy (BIS)...
August 23, 2016: Journal of Nephrology
Anders Helander, Matilda Bäckberg
No abstract text is available yet for this article.
August 23, 2016: Clinical Toxicology
Stefan Siebert, Celina E Juliano
Mechanisms of sex determination vary greatly among animals. Here we survey what is known in Cnidaria, the clade that forms the sister group to Bilateria and shows a broad array of sexual strategies and sexual plasticity. This observed diversity makes Cnidaria a well-suited taxon for the study of the evolution of sex determination, as closely related species can have different mechanisms, which allows for comparative studies. In this review, we survey the extensive descriptive data on sexual systems (e.g. gonochorism and hermaphroditism) and the plasticity of sex in various cnidarian taxa...
August 17, 2016: Molecular Reproduction and Development
Yoshinori Hasegawa, Takashi Watanabe, Masaki Takazawa, Osamu Ohara, Shin Kubota
In most animals, aging is an irreversible process; however the species Turritopsis sp. has been observed to undergo a rejuvenation process as many as 14 times. In the present study, we used multiplexed RNA libraries to obtain the transcriptome from four developmental stages (St) of Turritopsis sp., including (I) immature medusa, (II) dumpling, (III) dumpling with a short stolon, and (IV) polyp, which had recently rejuvenated. A total of 4.02 billion paired-end reads were assembled de novo, yielding 90,327 contigs...
August 2016: Zoological Science
Jácint Tökölyi, Zsófia Ősz, Flóra Sebestyén, Zoltán Barta
Freshwater hydra are among the few animal groups that show negligible senescence and can maintain high survival and reproduction rates when kept under stable conditions in the laboratory. Yet, one species of Hydra (H. oligactis) undergoes a senescence-like process in which polyps degenerate and die after sexual reproduction. The ultimate factors responsible for this phenomenon are unclear. High mortality in reproducing animals could be the consequence of increased allocation of resources to reproduction at the expense of somatic maintenance...
June 23, 2016: Zoology: Analysis of Complex Systems, ZACS
V V Kulayeva, V L Bykov
The effect of Hydra peptide morphogen (HPM) on quantitative histochemical and morphometric parameters of the thyroid gland (TG) was studied. The experiments were conducted on 40 outbred albino male mice weighing 20-25 g, which were injected intraperitoneally with HPM at the dose of 100 μg/kg of body weight per day for 5 days. Relative volumes occupied by the epithelium (E), including its follicular (E(f)), interfollicular (E(i)) components, and colloid (C) were determined using stereological method on TG transverse sections...
2016: Morfologi︠a︡
Lucas Leclère, Richard R Copley, Tsuyoshi Momose, Evelyn Houliston
The fresh water polyp Hydra provides textbook experimental demonstration of positional information gradients and regeneration processes. Developmental biologists are thus familiar with Hydra, but may not appreciate that it is a relatively simple member of the Hydrozoa, a group of mostly marine cnidarians with complex and diverse life cycles, exhibiting extensive phenotypic plasticity and regenerative capabilities. Hydrozoan species offer extensive opportunities to address many developmental mechanisms relevant across the animal kingdom...
July 29, 2016: Current Opinion in Genetics & Development
A Concas, R Imperatore, F Santoru, A Locci, P Porcu, L Cristino, P Pierobon
γ-aminobutyric acid (GABA) receptors, responding to GABA positive allosteric modulators, are present in the freshwater polyp Hydra vulgaris (Cnidaria, Hydrozoa), one of the most primitive metazoans to develop a nervous system. We examined the occurrence and distribution of GABAA receptor subunits in Hydra tissues by western blot and immunohistochemistry. Antibodies against different GABAA receptor subunits were used in Hydra membrane preparations. Unique protein bands, inhibited by the specific peptide, appeared at 35, 60, ∼50 and ∼52 kDa in membranes incubated with α3, β1, γ3 or δ antibodies, respectively...
July 23, 2016: Neurochemical Research
Yong-Shun Huang, Han-Lin Huang, Qi-Feng Wu, Li-Hua Xia, Ming Huang, Xin-Xiang Qiu, Shan-Yu Zhou
The present study aimed to explore the stability, curability and sequelae of cases of Trichloroethylene (TCE) Hypersensitivity Syndrome (THS), and to investigate the causal allergens of THS. Two cases of THS were followed-up in the current study; both cases were healing following glucocorticoid therapy and were discharged >10 weeks prior to follow-up. A questionnaire investigation, health examination and patch test were performed. Allergens of TCE and its metabolites, including chloral hydrate, trichloroethanol (TCOH) and trichloroacetic acid, were applied in the patch test; 4 controls were included...
August 2016: Experimental and Therapeutic Medicine
Anbazhagan Murugadas, Mohammed Zeeshan, Kaliannan Thamaraiselvi, Surendra Ghaskadbi, Mohammad Abdulkader Akbarsha
Nanotechnology has emerged as a powerful field of applied research. However, the potential toxicity of nano-materials is a cause of concern. A thorough toxicological investigation is required before a nanomaterial is evaluated for application of any kind. In this context, there is concerted effort to find appropriate test systems to assess the toxicity of nanomaterials. Toxicity of a nanomaterial greatly depends on its physicochemical properties and the biological system with which it interacts. The present research was carried out with a view to generate data on eco-toxicological impacts of copper oxide nanorod (CuO NR) in Hydra magnipapillata 105 at organismal, cellular and molecular levels...
2016: Scientific Reports
Lucas A Cieza, Simon Casassus, John Tobin, Steven P Bos, Jonathan P Williams, Sebastian Perez, Zhaohuan Zhu, Claudio Caceres, Hector Canovas, Michael M Dunham, Antonio Hales, Jose L Prieto, David A Principe, Matthias R Schreiber, Dary Ruiz-Rodriguez, Alice Zurlo
A snow-line is the region of a protoplanetary disk at which a major volatile, such as water or carbon monoxide, reaches its condensation temperature. Snow-lines play a crucial role in disk evolution by promoting the rapid growth of ice-covered grains. Signatures of the carbon monoxide snow-line (at temperatures of around 20 kelvin) have recently been imaged in the disks surrounding the pre-main-sequence stars TW Hydra and HD163296 (refs 3, 10), at distances of about 30 astronomical units (au) from the star...
July 14, 2016: Nature
Masakazu Ishikawa, Hiroshi Shimizu, Masafumi Nozawa, Kazuho Ikeo, Takashi Gojobori
In the Hydra vulgaris group, only 2 of the 25 strains in the collection of the National Institute of Genetics in Japan currently show endosymbiosis with green algae. However, whether the other non-symbiotic strains also have the potential to harbor algae remains unknown. The endosymbiotic potential of non-symbiotic strains that can harbor algae may have been acquired before or during divergence of the strains. With the aim of understanding the evolutionary process of endosymbiosis in the H. vulgaris group, we examined the endosymbiotic potential of non-symbiotic strains of the H...
October 2016: Molecular Phylogenetics and Evolution
Yunwi Heo, Young Chul Kwon, Seong Kyeong Bae, Duhyeon Hwang, Hye Ryeon Yang, Indu Choudhary, Hyunkyoung Lee, Seungshic Yum, Kyoungsoon Shin, Won Duk Yoon, Changkeun Kang, Euikyung Kim
An enzyme in a nematocyst extract of the Nemopilema nomurai jellyfish, caught off the coast of the Republic of Korea, catalyzed the cleavage of chymotrypsin substrate in an amidolytic kinetic assay, and this activity was inhibited by the serine protease inhibitor, phenylmethanesulfonyl fluoride. We isolated the full-length cDNA sequence of this enzyme, which contains 850 nucleotides, with an open reading frame of 801 encoding 266 amino acids. A blast analysis of the deduced amino acid sequence showed 41% identity with human chymotrypsin-like (CTRL) and the CTRL-1 precursor...
2016: Toxins
Usmary S Siqueira, Luciana G Orsini Valente, Marco Túlio de Mello, Vera L Szejnfeld, Marcelo M Pinheiro
OBJECTIVE: The purpose of this study was to compare the effectiveness of land-based (LB) and water-based (WB) aerobic exercises in women with rheumatoid arthritis (RA). DESIGN: A total of 133 women with RA were included in this randomized, blinded, prospective, 16-week controlled trial. The subjects were randomized into 3 groups: WB (n = 33), LB (n = 33), and control (n = 34). Muscle strength (MS) was measured using an isokinetic dynamometer. Disease activity (DAS-28) and functional ability (health assessment questionnaire) were measured by an expert rheumatologist...
July 6, 2016: American Journal of Physical Medicine & Rehabilitation
Michael H Cortez, Peter A Abrams
A hydra effect occurs when the mean density of a species increases in response to greater mortality. We show that, in a stable multispecies system, a species exhibits a hydra effect only if maintaining that species at its equilibrium density destabilizes the system. The stability of the original system is due to the responses of the hydra-effect species to changes in the other species' densities. If that dynamical feedback is removed by fixing the density of the hydra-effect species, large changes in the community make-up (including the possibility of species extinction) can occur...
May 2016: Ecology
L A Hufnagel, G Kass-Simon
In Hydra vulgaris, physiological and pharmacological evidence exists for a hypostomal circumferential neuro-effector pathway that initiates ectodermal pacemaker activity at tentacular-hypostomal loci coordinating body and tentacle contractions. Here, we describe an ectodermal nerve ring that runs below and between the tentacles, and an anti-GABAB receptor antibody-labeled ring coincident with it. The location of this ring is consistent with the physiology of the hypostomal pacemaker systems of hydra. We also describe a distally located, ectodermal ring of nerve fibers that is not associated with anti-GABAB receptor antibody labeling...
June 25, 2016: Cell and Tissue Research
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