Keine Mutationsauslösung durch 5-Äthyl-2′-desoxyuridin (ÄDU) bei Drosophila melanogaster

Summary The rate of sex-linked recessive lethals as well as of translocations between 2^nd and 3^rd chromosome was determined in a multipurpose strain ofDrosophila melanogaster after intraperitoneal injection of 5-ethyl-2-deoxyuridine. No mutations, however, were observed after that treatment. These findings confirm the results of other investigators with T-2-phages and are in good agreement with theoretical considerations.     

Calcium and magnesium induced changes in the relative fluidity of phosphatidylcholine liposomes

The effect of Ca²⁺ and Mg²⁺ on relative fluidity of phosphatidylcholine liposomes was studied by measuring the degree of chlorophyll fluorescence polarization. An increase in the degree of fluorescence polarization was observed on incubation of liposomes with different concentrations of Ca²⁺ or Mg²⁺. The results have been interpreted on the basis of increase in the size of liposomes which could be brought about by calcium or magnesium induced fusion of small unilamellar liposomes to form larger vesicles. Fusion of liposomes has also been confirmed by the experiments on efficiency of energy transfer from chlorophyll b to chlorophyll a, and transmission electron microscopy of liposomes before and after incubation with Ca²⁺ and Mg²⁺.     

Lincomycin-induced alteration in the contents of chlorophyll-protein complexes of dimorphic maize chloroplasts and its effect on the temperature-induced spectral changes

The difference spectroscopy technique has been utilized to investigate the temperature-induced spectral changes in mesophyll and bundle sheath chloroplasts of maize ( Zea mays L. cv. Ganga-5) in order to assess the role of different pigment-protein complexes in the manifestation of temperature effect on the chloroplast membranes. Cooling and heating of both mesophyll and bundle sheath chloroplasts resulted in absorbance difference (AA) bands at similar wavelengths but the degree of absorb-ance changes were significantly higher in bundle sheath chloroplasts. For example, upon cooling to 7-8°C, positive AA bands were observed at 440, 490 and 680 nm in mesophyll chloroplasts and at 440, 495–500 and 680 nm in bundle sheath chloroplasts but the absorbance change at 680 nm was ca 2% in mesophyll chloroplasts, whereas it was ca 5% in bundle sheath chloroplasts, which have a lower content of light-harvesting pigment-protein complex. The role of chlorophyll-protein complexes was further investigated by monitoring the temperature-induced spectral changes of mesophyll and bundle sheath chloroplasts isolated from lincomycin-treated maize plants where lincomycin selectively inhibits the biosynthesis of specific chlorophyll-protein complexes. Results indicated that depletion of certain pigment-protein complexes in mesophyll chloroplasts made them more susceptible (a ca 4% vs ca 2% absorbance change upon cooling and a ca 6% vs ca 4% absorbance change upon heating) and less tolerant to temperature variation (a 76% vs 39% reversibility during ambient→Cooling→ambient temperature cycle). The data indicate that pigment-protein complexes play a significant role in protecting the chloroplast membranes against temperature variation.     

Chronobiological perspectives on myocardial electrophysiological parameters under three types of general anaesthesia in a rat model

The specific aim of the present study, with respect to dependence on the light–dark (LD) cycle under in vivo conditions in spontaneously breathing rats was to review initial state in electrophysiological parameters that may predict the development of heart rhythm disorders in pentobarbital (40 mg/kg), ketamine–xylazine (100 + 15 mg/kg) and zoletil (30 mg/kg) anaesthetized animals. The study was performed using female Wistar rats that were adaptated to an LD cycle (12 h:12 h). Heart rate, PQ and QT intervals were evaluated for their dependence on the LD cycle. The longest PQ interval duration is under zoletil anaesthesia in the light period and the longest QT interval duration is under ketamine–xylazine anaesthesia in both light periods. We concluded that the most significant predisposition toward the development of ventricular arrhythmias originating from disorders of impulse production and conduction occurred under zoletil anaesthesia in the light period; those resulting from disorders in the dispersion of refractory periods occurred under ketamine–xylazine anaesthesia in both the light periods.     

An ex-situ and in vitro approach towards the bioremediation of carcinogenic hexavalent chromium

Abstract

Chromium, ranking the second most among toxic heavy metal pollutants in the world, causing respiratory, cardiovascular and renal problems in human beings is under study herein. We examined the biological remediation of the carcinogenic Cr (VI) polluted soils by indigenous yeast isolates. The total element analysis of the treated sample was determined by Energy Dispersion X-ray Micro Analysis (EDXMA). The sample under study was observed to have a high concentration of 458.29 mgKg^?1 Cr (VI), determined by Atomic Absorption Spectroscopy (AAS) and DPC analysis. The most tolerant isolate designated as CSR was used for in vitro and ex-situ bioremediation studies of Cr (VI). The isolate achieved significant bioremediation of 86% in vitro and 75.12% in ex-situ method. The optimal conditions for in vitro bioremediation were found to be 28?°C and a pH of 6. The ITS1, 5.8S rRNA and D1, D2 domain of LSU rRNA gene characterization of the isolate CSR illustrated that it belongs to Ustilago genera. The isolate was deposited in NCBI GenBank as Ustilago sp. CSR (KY284846). Although, Ustilago is generally a pathogenic fungus, our study opens up the scope of using Ustilago spp. for bioremediation of the carcinogenic heavy metal Chromium.     

Airborne and indigenous microbiomes co-drive the rebound of antibiotic resistome during compost storage

Composting is widely used to reduce the abundance of antibiotic resistance genes (ARGs) in solid waste. While ARG dynamics have been extensively investigated during composting, the fate and abundance of residual ARGs during the storage remain unexplored. Here, we tested experimentally how ARG and mobile genetic element (MGE) abundances change during compost storage using metagenomics, quantitative PCR and direct culturing. We found that 43.8% of ARGs and 39.9% of MGEs quickly recovered already during the first week of storage. This rebound effect was mainly driven by the regrowth of indigenous, antibiotic-resistant bacteria that survived the composting. Bacterial transmission from the surrounding air had a much smaller effect, being most evident as MGE rebound during the later stages of storage. While hyperthermophilic composting was more efficient at reducing the relative abundance of ARGs and MGEs, relatively greater ARG rebound was observed during the storage of hyperthermophilic compost, exceeding the initial levels of untreated sewage sludge. Our study reveals that residual ARGs and MGEs left in the treated compost can quickly rebound during the storage via airborne introduction and regrowth of surviving bacteria, highlighting the need to develop better storage strategies to prevent the rebound of ARGs and MGEs after composting.     

Culture of a Gastric Non‐Helicobacter pylori Helicobacter from the Stomach of a 14‐Year‐Old Girl

Helicobacter felis belongs to the fastidious gastric non‐Helicobacter pylori helicobacter species that are typically found in the stomach of cats and dogs. These bacteria have the potential to colonize the human stomach and are then associated with gastritis, gastroduodenal ulcers, and MALT lymphoma. Strains cultured from the human stomach are rare. Here, we present the first isolation of H. felis from a gastric biopsy specimen of a 14‐year‐old girl who presented with persistent epigastric pain. The strain was cultured using our routine protocol for H. pylori and identified by phylogenetic analyses of partial urease AB and gyrB gene sequences.     

EBF2 Determines and Maintains Brown Adipocyte Identity

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Highlights? Ebf2 is selectively expressed in brown relative to white adipocytes and binds to chromatin at brown fat-specific target sites of Pparγ ? Ebf2 expression in white fat or muscle precursor cells recruits Pparγ to its brown fat-specific gene targets and drives a complete program of brown adipocyte differentiation ? Brown adipose cells and tissue from Ebf2-deficient mice display a complete loss of thermogenic characteristics while gaining molecular attributes of white adipose     

Role of the Arabidopsis PIN6 Auxin Transporter in Auxin Homeostasis and Auxin-Mediated Development

Plant-specific PIN-formed (PIN) efflux transporters for the plant hormone auxin are required for tissue-specific directional auxin transport and cellular auxin homeostasis. The Arabidopsis PIN protein family has been shown to play important roles in developmental processes such as embryogenesis, organogenesis, vascular tissue differentiation, root meristem patterning and tropic growth. Here we analyzed roles of the less characterised Arabidopsis PIN6 auxin transporter. PIN6 is auxin-inducible and is expressed during multiple auxin–regulated developmental processes. Loss of pin6 function interfered with primary root growth and lateral root development. Misexpression of PIN6 affected auxin transport and interfered with auxin homeostasis in other growth processes such as shoot apical dominance, lateral root primordia development, adventitious root formation, root hair outgrowth and root waving. These changes in auxin-regulated growth correlated with a reduction in total auxin transport as well as with an altered activity of DR5-GUS auxin response reporter. Overall, the data indicate that PIN6 regulates auxin homeostasis during plant development.