Characterization of antimicrobial compound produced from Hericium erinaceus combating Campylobacter jejuni NCTC11168

Background: Campylobacter jejuni is the most common cause of enteric infections, particularly among children, resulting in severe diarrhea. Increasing drug resistance of this bacterium against standard antibiotics, favors investigations into additional anti-Campylobacter medications that are already used to overcome effects on enteric infections. Methods: Anti-bacterial activity using well diffusion assay of seventeen fungal extracts were tested against C. jejuni NCTC11168. The obtained results of antibacterial screening showed that different tested fungal isolates have different antimicrobial activities, where Hericium erinaceus extract was the highest activity against tested bacterium. Results: Fractionation pattern has been done by column chromatography. Furthermore, purity was estimated by thin layer chromatography (TLC). Minimal inhibitory concertation (MIC) for the purified compound was 7.81μg/ml. Cytotoxicity for the purified compound was evaluated to be 170μg/ml. 1HNMR, IR and GC-Mass were performed for illustration of suggested structure of bioactive compound purified from H. erinaceus. Conclusion: The data presented here suggested that H. erinaceus could potentially be used in modern applications aimed at the treatment or prevention of Campylobacter jejuni infection.

Determination of the Ni isotope fractionation in microfossils embedded in the aragonite phase

<p>Stable nickel isotopes are known to fractionate by biological processes and their measurements can be important biomarker. In searches for ancient fossilised materials such as microbial cells, the Ni isotope fractionation record can be preserved after death and fossilization of microstructures. Typically, transition metal isotopes in microfossils are difficult to measure accurately because of their low concentration in the fossil. Furthermore, microsized fossil structures  are difficult to isolate from the host phase. Thus, the measurement of their chemical composition can be conducted only by a few  analytical methods. We have applied femtosecond-laser ablation/ionisation time-of-flight mass spectrometry (LIMS) to measure chemical composition of the fossilised material embedded in the aragonite phase and accurately derive the Ni isotopic fractionation pattern. High resolution depth profiling method was applied to isolate fossilised material composition from the host phase. The mass peak intensity correlation and peak integration methods were subsequently applied to derive isotope concentrations. The accuracies and precision in permill level or better of the isotope values were achieved. For comparison the studies of Ni isotopes were conducted on inorganic samples. The instrument used in the studies is a miniature mass analyser developed for space research holding promisses that differentiation between abiotic and biogenic microstructures in rocks can be studied also in situ on the surfaces of Solar System bodies.</p><p>References</p><p>1. U. Rohner et al., Meas. Sci. Technol. 14 (2003) 2159–2164</p><p>2. A. Riedo et al., JAAS, 28:1256–1269, 2013</p><p>3. A. Neubeck et al., Int. J. Astrobiology, 15, 133-146, 2016</p><p>4. M. Tulej et al., Astrobiology, 2015, DOI: 10.1089/ast.2015.1304;JAAS,33(8):1292-1303, 2018</p><p>5. S. Meyer et al., J. Mass Spectrom. 2017, DOI: org/10.1002/jms.3964   </p><p>6. R. Wisendanger et al., J. Chemometrics, 2018, DOI: 10.1002/cem.3081</p><p>7. V. Grimaudo et al., Anal. Chem., 2018, DOI: 10.1021/acs.analchem.7b05313</p><p> </p><div> </div>

Mapping of Uranium in Surrogate Nuclear Debris Using Laser-Induced Breakdown Spectroscopy (LIBS)

This work describes the use of a laser-induced breakdown spectroscopy (LIBS) system to conduct macroscopic elemental mapping of uranium and iron on the exterior surface and interior center cross-section of surrogate nuclear debris for the first time. The results suggest that similar LIBS systems could be packaged for use as an effective instrument for screening samples during collection activities in the field or to conduct process control measurements during the production of debris surrogates. The technique focuses on the mitigation of chemical and physical matrix effects of four uranium atomic emission lines, relatively free of interferences and of good analytical value. At a spatial resolution of 0.5 mm, a material fractionation pattern in the surrogate debris is identified and discussed in terms of constituent melting temperatures and thermal gradients experienced.

Saccharomyces cerevisiae Rbg1 Protein and Its Binding Partner Gir2 Interact on Polyribosomes with Gcn1

ABSTRACT Rbg1 is a previously uncharacterized protein of Saccharomyces cerevisiae belonging to the Obg/CgtA subfamily of GTP-binding proteins whose members are involved in ribosome function in both prokaryotes and eukaryotes. We show here that Rbg1 specifically associates with translating ribosomes. In addition, in this study proteins were identified that interact with Rbg1 by yeast two-hybrid screening and include Tma46, Ygr250c, Yap1, and Gir2. Gir2 contains a GI (Gcn2 and Impact) domain similar to that of Gcn2, an essential factor of the general amino acid control pathway required for overcoming amino acid shortage. Interestingly, we found that Gir2, like Gcn2, interacts with Gcn1 through its GI domain, and overexpression of Gir2, under conditions mimicking amino acid starvation, resulted in inhibition of growth that could be reversed by Gcn2 co-overexpression. Moreover, we found that Gir2 also cofractionated with polyribosomes, and this fractionation pattern was partially dependent on the presence of Gcn1. Based on these findings, we conclude that Rbg1 and its interacting partner Gir2 associate with ribosomes, and their possible biological roles are discussed.

Sulphur isotope variations in diagenetic pyrite from core plug to sub-millimetre scales

Sulphur isotope ratio measurements (δ34S) of diagenetic pyrite are commonly used to identify S sources and mechanisms of sulphide formation in basinal sediments. This study reports such data for a diagenetic pyrite nodule from the Brent Group sandstones of the northern North Sea at three sampling scales: 50 cm (core subsample), 500 μm (laser microprobe) and 50 μm (ion microprobe). Similar δ34S variations are found by the laser and ion microprobe techniques. There is a very wide range in δ34S (<−10% to >+50%) within the nodule and isotopically heavy S (δ34S >+20%) is common at all scales. The nodule δ34S distribution does not fit a Rayleigh fractionation pattern. The laser microprobe sampling at 100–500 μm scales seems to be adequate to characterize S isotope variations in this material.