Identification of non-coding RNA interactions that dictate Staphylococcus aureus virulence

Staphylococcus aureus is a bacterium which has gathered much attention over the past decade due to the emergence of both antibiotic-resistant and hyper-aggressive strains. These pose a significant threat to human health, particularly to individuals already weakened through other illnesses. When S. aureus enters the human bloodstream, it must adapt in order to survive the challenging conditions faced. In particular, it must respond to the nutritional environment of the blood which is depleted in essential cofactors such as free iron. Additionally, S. aureus must survive attacks from the host immune system which will attempt to kill the invader through phagocytes and the production of antibodies. Theworkcarriedouthereaimedtounderstandhowsmall,non-codingRNAs(sRNAs) regulate S. aureus’ adaptation to the host bloodstream. These sRNAs are typically associated with regulating the translational efficiency and stability of mRNAs. Through use of a technique called “UV cross-linking, ligation and sequencing of hybrids” (CLASH), I identified novel targets of many sRNAs. In particular, I studied how RsaA, an sRNA involved in membrane homeostasis, regulates the translation of a transmembrane transporter involved in antiseptic and antibiotic resistance. Additionally, I identified interactions between RsaE, an sRNA involved in metabolism, and several toxin mRNAs from the phenol-soluble modulin class. This is a novel example of the direct link between cellular metabolism and virulence. However, the most striking finding was that not only do sRNAs target mRNAs, but that they also target each other. I focused on two distinct sRNA – sRNA interactions; one between RsaA and RNAIII, and another between RsaE and RsaOG. The interaction between RsaE and RsaOG is an example of a so-called ’sponging interaction’, where RsaOG is able to antagonise the activity of RsaE. This has the effect of freeing RsaE’s targets from their regulation. I hypothesise that this ultimately induces the necessary metabolic changes required in order to survive the immediate nutritional stresses incurred after entering the bloodstream. Regarding RsaA and RNAIII, I hypothesise that this interaction is responsible for balancing virulent versus dormant behaviour. I suggest that RsaA is able to induce the destruction of RNAIII in order to steer the cell away from aggressive behaviour and into a more latent state. Additionally, the interaction between these two sRNAs also appears to operate on exquisitely short timescales, demonstrating how capable bacteria are at adapting to stresses. Ultimately, this work suggests that interactions between sRNAs are likely to be widespread and form a crucial aspect of stress responses in general. The experiments detailed herein have certainly not exhausted the produced data and I suspect that it will be utilised further in the future

Micropropagation and in vitro studies of Pinus patula Scheide et Deppe.

Thesis (M.Sc.)-University of Natal, Durban, 1993.For the South African forestry industry, the patula pine (Pinus patula) is the most commercially important softwood species. A pine clonal programme has yet to be fully implemented in this country and at present much effort is being made to establish clonal plantings of selected trees. In order to accomplish this, it is essential that satisfactory commercially viable propagation technologies be developed for this species. This study examined the possibilities and constraints of three different in vitro systems for mass propagation of rare and important P. patula material. Seed germination and sterilisation techniques were developed for adventitious bud and somatic embryogenesis experimentation. Adventitious buds were initiated from excised 'mature P. patula embryos cultured on LM medium containing 5 mg 1-1 BA. Although, between 50 and 60% of the embryo explants produced adventitious buds, only 3-5 buds per explant actually developed further to form distinct shoots. The adventitious shoots elongated slowly (±8 mm in 2 months) on LM medium, containing 10 g 1-1 activated charcoal. Axillary buds were induced on 10 week-old juvenile shoots, after the development of an effective surface sterilisation procedure, using 0.02% HgCL2. The effect of removing the apex and trimming the needles on bud induction was significant. Dwarf shoots elongated at a rate of 25 mm in 5 weeks. Rooting studies conducted on juvenile P. patula shoots indicated that the most effective treatment was wounding the shoot base and placing the shoot in composted bark growing medium, under a greenhouse mist regime. Rooting percentages were low (50%). Included in this study is the first successful production of somatic pro-embryos from mature Pinus patula embryos. Calli were produced on LM induction medium containing 2 mg 1-1 2,4-D. Cultures were first placed in the dark for 4 weeks and then transferred to a 16 h photoperiod for a further 2 weeks, after which Stage 1 embryogenic cells were observed. When calli were placed on LM maturation medium, containing 12 mg 1-1 ABA, for a further 6-8 weeks, pro-embryo structures (maximum of 7 pro-embryos per callus) were detected embedded In the callus mass. Hence, investigations into the development of protocols for the micropropagation of Pinus patula, were undertaken. Two major constraints for applying in vitro techniques to the commercial production of pine were identified: the poor yield of shoots and pro-embryos and the length of time taken for plantlets to be produced. This study, however, provides some fundamental knowledge and background work required by tree breeders who wish to implement biotechnological techniques in the selection and improvement of P. patula genotypes

Nonequilibrium Neutrino Oscillations in the Early Universe with an Inverted Neutrino-Mass Hierarchy

The annihilation of electron-positron pairs around one second after the big bang distorts the Fermi-Dirac spectrum of neutrino energies. We determine the distortions assuming neutrino mixing with an inverted neutrino-mass hierarchy. Nonequilibrium thermodynamics, the Boltzmann equation, and numerical integration are used to achieve the results. The various types of neutrino behavior are established as a function of masses and mixing angles.Comment: 9 pages in Latex with 6 figures (10 postscript files

Myoepithelioma within the carpal tunnel: a case report and review of the literature

Myoepitheliomas of the extremity are rare and usually benign, while a minority display malignant features. This case demonstrates the diagnosis and management of myoepithelioma within the carpal tunnel. Clinical and radiological tumour features were evaluated. Hematoxylin and eosin stained tumour sections were examined, and immunohistochemistry was performed. Histology revealed a nodular mass of epithelioid cells in clusters within a myxoid/chondroid stroma. No mitoses were noted. Cytokeratins, neuron-specific enolase, synaptophysin, glial fibrillary acidic protein, and S100 were positive on immunohistochemistry. A literature review revealed very few prior reports of myoepithelioma in the wrist, and limited data concerning any relationship between recurrence and quality of surgical margins. In this case, wide local excision would have significantly compromised dominant hand function, and therefore a marginal excision was deemed appropriate in the context of bland histological features. Surgical margins noted in future case reports will aid clinical decision making

Bimodal Coherence in Dense Self-Interacting Neutrino Gases

Analytical solutions are obtained to the nonlinear equations describing neutrino oscillations when explicit neutrino-antineutrino asymmetries are present. Such a system occurs in the early Universe if neutrinos have a non-zero chemical potential. Solutions to the equations lead to a new type of coherent behavior governed by two modes. These bimodal solutions provide new insights into dense neutrino gases and into neutrino oscillations in the early Universe, thereby allowing one to surmise the flavor behavior of neutrinos with a non-zero chemical potential.Comment: 21 pages in Latex, 11 figures packaged in one Postscript file. Figures also obtainable as 20 gif files at http://www.sci.ccny.cuny.edu/~ssamuel/bimodalfigs.html Revision on 4/19/96 was to pack the figures more sensibly. This paper is to appear in a May issue of Phys. Rev.

Neutrino Oscillations in the Early Universe with Nonequilibrium Neutrino Distributions

Around one second after the big bang, neutrino decoupling and $e^+$-$e^-$ annihilation distort the Fermi-Dirac spectrum of neutrino energies. Assuming neutrinos have masses and can mix, we compute the distortions using nonequilibrium thermodynamics and the Boltzmann equation. The flavor behavior of neutrinos is studied during and following the generation of the distortion.Comment: accepted for publication in Physical Review

A systematic review, meta-analysis and metaregression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults

Objective We performed a systematic review, metaanalysis and meta-regression to determine if dietary protein supplementation augments resistance exercise training (RET)-induced gains in muscle mass and strength. Data sources A systematic search of Medline, Embase, CINAHL and SportDiscus. Eligibility criteria Only randomised controlled trials with RET ≥6 weeks in duration and dietary protein supplementation. Design Random-effects meta-analyses and metaregressions with four a priori determined covariates. Twophase break point analysis was used to determine the relationship between total protein intake and changes in fat-free mass (FFM). ResultsData from 49 studies with 1863 participants showed that dietary protein supplementation significantly (all p Summary/conclusion Dietary protein supplementation significantly enhanced changes in muscle strength and size during prolonged RET in healthy adults. Increasing age reduces and training experience increases the efficacy of protein supplementation during RET. With protein supplementation, protein intakes at amounts greater than ~1.6 g/kg/day do not further contribute RET-induced gains in FFM

Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & Nemésio 2007; Donegan 2008, 2009; Nemésio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016