piRNAs and Aubergine cooperate with Wispy poly(A) polymerase to stabilize mRNAs in the germ plasm

Piwi-interacting RNAs (piRNAs) and PIWI proteins play a crucial role in germ cells by repressing transposable elements and regulating gene expression. In Drosophila, maternal piRNAs are loaded into the embryo mostly bound to the PIWI protein Aubergine (Aub). Aub targets maternal mRNAs through incomplete base-pairing with piRNAs and can induce their destabilization in the somatic part of the embryo. Paradoxically, these Aub-dependent unstable mRNAs encode germ cell determinants that are selectively stabilized in the germ plasm. Here we show that piRNAs and Aub actively protect germ cell mRNAs in the germ plasm. Aub directly interacts with the germline-specific poly(A) polymerase Wispy, thus leading to mRNA polyadenylation and stabilization in the germ plasm. These results reveal a role for piRNAs in mRNA stabilization and identify Aub as an interactor of Wispy for mRNA polyadenylation. They further highlight the role of Aub and piRNAs in embryonic patterning through two opposite functions

Antipodean Theory for Educational Research

published_or_final_versio

Wirkung des Fusarientoxins Deoxynivalenol beim wachsenden Schwein in Abhängigkeit von der Darreichungsform

In der Literatur finden sich zahlreiche widersprüchliche Angaben zur Wirkung des Mykotoxins Deoxynivalenol (DON) bei Schweinen, wobei meist für natürlich mit DON kontaminiertes Futter (DONnat) stärkere Wirkungen beobachtet wurden als für künstlich mit DON-Reinsubstanz kontaminiertes Futter (DONrein). In dieser Arbeit wurde der Einfluß von Deoxynivalenol (DON) auf die Entwicklung wachsender Schweine untersucht. Von besonderem Interesse war hierbei die Frage, inwieweit für natürlich kontaminiertes Futter beobachtete Wirkungen (DONnat) auch durch Verfütterung einer mit DON-Reintoxin künstlich kontaminierten, getreidefreien Futtermatrix (DONrein) reproduziert werden können. Hierzu wurden männliche Läuferschweine einerseits mit einer natürlich kontaminierten Getreideration und andereseits mit einer getreidefreien Ration auf Kartoffelbasis unter Zusatz von Reintoxin gefüttert. Aufgrund der baulichen Gegebenheiten sowie der tierschutzrechtlichen Bestimmungen, wurde das Projekt in Teilabschnitten umgesetzt. Neben den Leistungsparametern Futteraufnahme und Gewichtsentwicklung wurden ferner Parameter wie Blut, Darmenzymatik, Gewebeveränderungen und DON-Metabolisierung im Kot untersucht. Zur Abschätzung der erforderlichen Toxingehalte für ein sicheres Auftreten eines Toxineffektes wurden in einem Vorversuch (Durchgang A) jeweils 5 Tiere parallel mit 2000 mg/kg und 4000 mg/kg DONnat bzw. DONrein belastet. Das Fütterungsregime entsprach einer restriktiven Futtervorlage, welche so bemessen war, dass sie einer ad libitum-Fütterung entsprechen sollte. Zu jeder Belastungsgruppe in jeder Futtervariante wurde eine Kontrollgruppe mitgeführt. Die Ergebnisse aus dem ersten Durchgang (A) zeigten lediglich Trends hinsichtlich einer möglichen Toxinwirkung auf. Insbesondere Tiere der natürlichen Belastungsgruppe wiesen Gewichtseinbußen auf. Demgegenüber waren in der Gruppe DONrein, trotz der hohen Toxinbelastung, keine Unterschiede der Leistungsparameter festzustellen. In einem zweiten Durchgang (B) wurde daraufhin jeweils 5 Tieren ausschließlich eine kontaminierte Weizenration mit einer DON-Belastung von 4000 mg/kg und 6000 mg/kg verabreicht, und im Anschluß daran in einem dritten Durchgang (C) wiederum jeweils 5 Tiere ausschließlich mit DONrein in Höhe von 4000 mg/kg und 6000 mg/kg in einer getreidefreien Futtermatrix belastet. Auch das Fütterungsregime wurde in diesen beiden Abschnitten an eine ad libitum-Fütterung adaptiert. Das variierte Versuchsverfahren in Durchgang B ließ signifikante Unterschiede in Gewichtsentwicklung und Futteraufnahme der Tiere erkennen, im gleichermaßen gestalteten Durchgang C konnte jedoch kein Einfluß des zugesetzten reinen DON in der getreidefreien Diät abgeleitet werden. Die Untersuchung der Blutparameter lieferte keinen Anhaltspunkt auf einen systemischen Toxineffekt. Veränderungen einzelner Parameter traten sporadisch und inkonstant auf. Die Thyroxingehalte stiegen nur in der Versuchsgruppe mit reinem Toxin regelmäßig in den Durchgängen A und C gegen Versuchsende an. In den Durchgängen A und B lagen die T4-Werte der getreidehaltig gefütterten Gruppen deutlich höher, als die der getreidefrei gefütterten Tiere, was allerdings der Diät zuzuschreiben war. In Versuchsdurchgang B fiel der Blut-Triglyceridgehalt mit einem signifikanten Anstieg auf, allerdings nur in der mittleren Belastungsgruppe 4000 mg/kg DONrein. Dagegen konnte in diesem Abschnitt ein signifikanter SDH-Anstieg in der Gruppe DONnat gefunden werden. Bezüglich der IgA-Gehalte im Serum waren zwischen den Behandlungen keine Unterschiede zu erkennen. Mit zunehmendem DON-Gehalt im Futter ließ sich lediglich ein Trend zu höheren IgA-Gehalten feststellen, der bei Verabreichung von DONnat deutlich ausgeprägter erschien. Die Fähigkeit der Darmmikroflora (aus dem Rektum), DON zu dem Metaboliten Deepoxy-Deoxynivalenol (DOM-1) zu transformieren war sowohl von der Darreichungsform und der Toxinmenge als auch vom Fütterungsregime abhängig. Der Anteil transformierender Mikroorganismen im Kot nahm unabhängig von der Darreichungsform mit steigender Toxinkonzentration im Futter zu. Bei den Kontrolltieren dagegen war kein einheitliches Muster abzuleiten. Ein Einfluß des Toxins auf den Proteingehalt der Darmmukosa sowie der ALT- und -KGDH-Aktivität der Enterozyten war nicht eindeutig zu bestimmen. Histologisch ließen sich vereinzelt deutlich Veränderungen der Mukosa von Magen und Darm finden, allerdings traten diese Veränderungen ebenfalls unabhängig von der Behandlung auf. Diese Arbeit zeigt den grundsätzlichen Unterschied bezüglich der Efffekte von DON als Reinsubstanz und als natürlich gebildetes Toxin in kontaminiertem Getreide auf. Die bislang festgestellten toxischen Wirkungen von DON sind allein durch Verabreichung der Reinsubstanz ohne natürliche Matrix nicht reproduzierbar. Das heißt, dass im natürlich kontaminierten Futter ein oder mehrere andere toxische Agentien zu den Vergiftungssymptomen beitragen oder diese sogar ausschließlich verursachen. Andererseits ist bei Vergiftungsfällen in der Praxis immer auch DON in entsprechenden Mengen nachzuweisen, DON könnte somit als Leitsubstanz benannt werden. Um die Zusammenhänge und auch um eine sichere Einschätzung der Gefährdung durch diese Substanz gewährleisten zu können, sind hierzu weitere Untersuchung erforderlich. Aber sowohl hinsichtlich der Kosten und des Aufwandes als auch unter Tierschutzaspekten sind die aufzustellenden Versuchskonzepte nur sehr schwer umsetzbar.Publications show a considerable amount of inconsistant information for effects of mycotoxin deoxynivalenol in pigs. Naturally contaminated feeds (DONnat) seem to cause more severe effects than pure DON in artificially contaminated feed (DONpure). This study examined the development of growing pigs under DON-influence. Most interestingly was the question, wether effects of DON-contaminated feed (DONnat) could be replicated using a grainless diet containing pure DON (DONpure). Therefore a group of male pigs were fed a diet containing naturally contaminated wheat and compared to another group fed a grainless diet based on potato supplemented with DONpure. Due to the building capacity and for reasons of animal welfare, the project had to be divided in several parts. Beside the performance parameters feed intake and weight development other parameters (blood, intestinal enzymes, tissue alterations and DON-metabolisation in feces) were examined. To estimate the required DON dose to provide certain toxic effects a preceding study (Part A) was drawn consisting of 4 groups with 5 animals each. The treatment was both naturally contaminated wheat diet and pure DON in grainless potato diet. The contents in both diets were 2000 mg/kg and 4000 mg/kg DONnat respectively DONpure. The amount of food was calculated corresponding to ad libitum feeding. Every treatment group was compared to a control group. The results of Part A only showed slight trends concerning a possible toxic effect. Especially the naturally contaminated group demonstrated weight loss. In contrast, there was no evidence of any toxic effect in the DONpure –group concerning performance. In a second study (Part B) 3 groups comprising 5 animals each received wheat diet, exclusively, containing 4000 mg/kg and 6000 mg/kg DONnat and control group, followed by Part C, altered by feeding grainless potato diet with corresponding amounts of DONpure. Also the feeding regime was changed to a real ad libitum feeding. The trial variation in Part B showed significant differences in weight gain and feed intake. These were not reproducible in Part C, no effect of admitted DONpure in grainless diet was derived. The examination of blood parameters gave no evidence of a systemic toxic effect. Alterations of single parameters were inconstant and intermittent. Only the thyroxin levels increased in the grainless group during Parts A and C at the end of each trial. In Part A and B the levels in the wheat diet groups increased, indicating an effect of the diet. In Part B, the blood triglycerides showed a significant rise, but only in the group with medium exposure of pure DON (4000 mg DONpure /kg). In contrast, a significant rise of SDH contents was found in the contaminated wheat diet group (DONnat). Regarding the serum IgA-levels no differences between the treatments could be diagnosed. With higher DON-levels in food a distinct trend to higher IgA-levels, esp. in the naturally contaminated group (DONnat), could be assessed. The ability of Intestinal flora (rectum) for DON-degradation (DOM-1) depended on both, sort of food (ingredients) and dosage and also the feeding regime. The fraction of transforming microorganisms in faeces rose with increasing toxin contents independent of diet. In contrast, the control animals showed no consistent pattern. The influence of protein content of intestinal mucosa and activity of ALT and -KGDH in enterocytes could not be identified clearly. Several mucosal variations of stomach and intestine were determined in histological examination. These changes also appeared independent of treatment. This study showed basic differences of pure DON and DON from a naturally contaminated source, referring to toxic effects. Only pure DON without natural material cannot bring out any toxic effect, which was described up to now. That means, there must be ne or more further agents in naturally contaminated material, supporting or just releasing an intoxication. On the other hand, in cases of intoxication DON is detected regularly. Therefore the conclusion for DON as leading substance may be established. For connections and a reliable estimation of the risks through this substance, further examinations are necessary. But expenses, complexity and also animal welfare reasons make the realisation of required trials very difficult

Seamless Gene Tagging by Endonuclease-Driven Homologous Recombination

Gene tagging facilitates systematic genomic and proteomic analyses but chromosomal tagging typically disrupts gene regulatory sequences. Here we describe a seamless gene tagging approach that preserves endogenous gene regulation and is potentially applicable in any species with efficient DNA double-strand break repair by homologous recombination. We implement seamless tagging in Saccharomyces cerevisiae and demonstrate its application for protein tagging while preserving simultaneously upstream and downstream gene regulatory elements. Seamless tagging is compatible with high-throughput strain construction using synthetic genetic arrays (SGA), enables functional analysis of transcription antisense to open reading frames and should facilitate systematic and minimally-invasive analysis of gene functions

The Unseeing Eye: Disability and the hauntology of Derrida’s ghost. A story in three parts

Through the employment of the three stanzas of Thomas Hardy’s poem ‘The Self-Unseeing’ this paper seeks to tremble the picture of disability located in the pedagogical materials in English Schools. By mobilising, and then reversing, Derrida’s concept of the visor and the ghost, as well as Bentham’s Panopticon, this story reveals the power of the Them, the Their and the They. In materialising the ghost of the real of disability within a utopia of hope this story deconstructs the power of Their transparent house by revealing disabled people as magnificent beings

Therapeutic hypothermia translates from ancient history in to practice

Acute postasphyxial encephalopathy around the time of birth remains a major cause of death and disability. The possibility that hypothermia may be able to prevent or lessen asphyxial brain injury is a “dream revisited”. In this review, a historical perspective is provided from the first reported use of therapeutic hypothermia for brain injuries in antiquity, to the present day. The first uncontrolled trials of cooling for resuscitation were reported more than 50 y ago. The seminal insight that led to the modern revival of studies of neuroprotection was that after profound asphyxia, many brain cells show initial recovery from the insult during a short “latent” phase, typically lasting ~6 h, only to die hours to days later during a “secondary” deterioration phase characterized by seizures, cytotoxic edema, and progressive failure of cerebral oxidative metabolism. Studies designed around this conceptual framework showed that mild hypothermia initiated as early as possible before the onset of secondary deterioration, and continued for a sufficient duration to allow the secondary deterioration to resolve, is associated with potent, long-lasting neuroprotection. There is now compelling evidence from randomized controlled trials that mild induced hypothermia significantly improves intact survival and neurodevelopmental outcomes to midchildhood

Post-transcriptional gene regulation: From genome-wide studies to principles

Post-transcriptional regulation of gene expression plays important roles in diverse cellular processes such as development, metabolism and cancer progression. Whereas many classical studies explored the mechanistics and physiological impact on specific mRNA substrates, the recent development of genome-wide analysis tools enables the study of post-transcriptional gene regulation on a global scale. Importantly, these studies revealed distinct programs of RNA regulation, suggesting a complex and versatile post-transcriptional regulatory network. This network is controlled by specific RNA-binding proteins and/or non-coding RNAs, which bind to specific sequence or structural elements in the RNAs and thereby regulate subsets of mRNAs that partly encode functionally related proteins. It will be a future challenge to link the spectra of targets for RNA-binding proteins to post-transcriptional regulatory programs and to reveal its physiological implications

Female Chimpanzees Use Copulation Calls Flexibly to Prevent Social Competition

The adaptive function of copulation calls in female primates has been debated for years. One influential idea is that copulation calls are a sexually selected trait, which enables females to advertise their receptive state to males. Male-male competition ensues and females benefit by getting better mating partners and higher quality offspring. We analysed the copulation calling behaviour of wild female chimpanzees (Pan troglodytes schweinfurthii) at Budongo Forest, Uganda, but found no support for the male-male competition hypothesis. Hormone analysis showed that the calling behaviour of copulating females was unrelated to their fertile period and likelihood of conception. Instead, females called significantly more while with high-ranking males, but suppressed their calls if high-ranking females were nearby. Copulation calling may therefore be one potential strategy employed by female chimpanzees to advertise receptivity to high-ranked males, confuse paternity and secure future support from these socially important individuals. Competition between females can be dangerously high in wild chimpanzees, and our results indicate that females use their copulation calls strategically to minimise the risks associated with such competition

IGFBP3 Colocalizes with and Regulates Hypocretin (Orexin)

Background: The sleep disorder narcolepsy is caused by a vast reduction in neurons producing the hypocretin (orexin) neuropeptides. Based on the tight association with HLA, narcolepsy is believed to result from an autoimmune attack, but the cause of hypocretin cell loss is still unknown. We performed gene expression profiling in the hypothalamus to identify novel genes dysregulated in narcolepsy, as these may be the target of autoimmune attack or modulate hypocretin gene expression. Methodology/Principal Findings: We used microarrays to compare the transcriptome in the posterior hypothalamus of (1) narcoleptic versus control postmortem human brains and (2) transgenic mice lacking hypocretin neurons versus wild type mice. Hypocretin was the most downregulated gene in human narcolepsy brains. Among many additional candidates, only one, insulin-like growth factor binding protein 3 (IGFBP3), was downregulated in both human and mouse models and coexpressed in hypocretin neurons. Functional analysis indicated decreased hypocretin messenger RNA and peptide content, and increased sleep in transgenic mice overexpressing human IGFBP3, an effect possibly mediated through decrease