Metabolome Analysis of Drosophila melanogaster during Embryogenesis

The Drosophila melanogaster embryo has been widely utilized as a model for genetics and developmental biology due to its small size, short generation time, and large brood size. Information on embryonic metabolism during developmental progression is important for further understanding the mechanisms of Drosophila embryogenesis. Therefore, the aim of this study is to assess the changes in embryos’ metabolome that occur at different stages of the Drosophila embryonic development. Time course samples of Drosophila embryos were subjected to GC/MS-based metabolome analysis for profiling of low molecular weight hydrophilic metabolites, including sugars, amino acids, and organic acids. The results showed that the metabolic profiles of Drosophila embryo varied during the course of development and there was a strong correlation between the metabolome and different embryonic stages. Using the metabolome information, we were able to establish a prediction model for developmental stages of embryos starting from their high-resolution quantitative metabolite composition. Among the important metabolites revealed from our model, we suggest that different amino acids appear to play distinct roles in different developmental stages and an appropriate balance in trehalose-glucose ratio is crucial to supply the carbohydrate source for the development of Drosophila embryo.     

Ubiquitin Modulates Liquid-Liquid Phase Separation of UBQLN2 via Disruption of Multivalent Interactions

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Small-scale experiments aimed at optimization of large-scale production of the microalga <Emphasis Type="Italic">Rhodomonas salina</Emphasis>

The cryptophyte Rhodomonas is an important feed item for live feed organisms in aquaculture and although large-scale cultivation of Rhodomonas in photobioreactors (PBRs) is feasible, the production needs to be optimized through further studies of specific factors. Through small-scale experiments, several factors relevant for an on-going large-scale production of Rhodomonas were studied and the results presented here provide a useful insight on factors that can help future large-scale production. The content of polyunsaturated fatty acids (PUFAs) and the temporal sedimentation was compared in five strains of Rhodomonas. Strain K-1487 (R. salina) was chosen as the most suitable for cultivation in PBRs due to a good biochemical content of PUFAs and low cell sedimentation. The f/2 growth medium used for cultivation was modified by excluding CoCl₂ which did not affect either growth rate or cell content of the PUFAs, DHA, EPA, and ARA. Furthermore, the growth medium was modified by adding the nitrogen source as ammonium (NH₄⁺), nitrate (NO₃^?), urea, or combinations of these, with NH₄⁺ yielding a significantly higher growth rate of 1.30?±?0.07 day^?1. The seawater used for cultivation was exposed to three types of treatments which gave no significant difference in the growth rate: (1) filtration (0.2 μm)?+?autoclaving, (2) filtration (0.2 μm)?+?UV-radiation, and (3) filtration (0.2 μm). Finally, the results for growth rates of inocula at initial densities ranging from 2000 to 200,000 cells mL^?1 showed that growth rate decreased with increasing density but a final density of 10⁶ cells mL^?1 was obtained fastest with the highest initial density. With the present findings, several barriers for effective cultivation of Rhodomonas are solved and future large-scale production has become a great step closer.     

Identification and Characterization of the Cecropin Antibacterial Protein Gene Locus in Drosophila virilis

Cecropin is a type of antibacterial peptide that is synthesized in response to infection and has been characterized in many insect species and one mammal. The Cecropin locus of Drosophila melanogaster also contains the gene Andropin, which has been identified only in this species and encodes a male-specific antibacterial peptide. As a first step in studying the molecular evolution of the cecropin and andropin genes among Drosophila species, we have isolated genomic clones that cover the Cecropin locus in Drosophila virilis. The cloned region totals approximately 25 kb, within which a 9-kb fragment contains four cecropin genes and one pseudogene. All four genes have a high level of sequence homology to D. melanogaster Cecropin, about 80% identity in the coding regions, and the intron positions are conserved. As in D. melanogaster and other insects, κB-related cis-regulatory elements are found upstream of these cecropin genes. An Andropin-related sequence was not identified in D. virilis; however, genome Southern hybridizations suggest that Andropin-related sequences are present in at least the melanogaster species subgroup. Analysis of 19 insect cecropin genes identifies a common ancestral Cecropin before the divergence of Diptera and Lepidoptera. In addition, D. melanogaster and D. virilis can be identified by monophyletic clades for Cecropin. In contrast, the Lepidopteran species show polyphyletic relationships for duplicated cecropin genes. Received: 12 August 1996 / Accepted: 18 October 1996     

South Asia as a Reservoir for the Global Spread of Ciprofloxacin-Resistant Shigella sonnei: A Cross-Sectional Study

BackgroundAntimicrobial resistance is a major issue in the Shigellae, particularly as a specific multidrug-resistant (MDR) lineage of Shigella sonnei (lineage III) is becoming globally dominant. Ciprofloxacin is a recommended treatment for Shigella infections. However, ciprofloxacin-resistant S. sonnei are being increasingly isolated in Asia and sporadically reported on other continents. We hypothesized that Asia is a primary hub for the recent international spread of ciprofloxacin-resistant S. sonnei.ConclusionsThis study suggests that a single clone, which is widespread in South Asia, is likely driving the current intercontinental surge of ciprofloxacin-resistant S. sonnei and is capable of establishing endemic transmission in new locations. Despite being limited in geographical scope, our work has major implications for understanding the international transfer of antimicrobial-resistant pathogens, with S. sonnei acting as a tractable model for studying how antimicrobial-resistant Gram-negative bacteria spread globally.     

IL-1 Contributes to the Anti-Cancer Efficacy of Ingenol Mebutate

Ingenol mebutate is approved for the topical treatment of actinic keratoses and may ultimately also find utility in treating skin cancers. Here we show that relapse rates of subcutaneous B16 melanoma tumours treated topically with ingenol mebutate were not significantly different in C57BL/6 and Rag1^-/- mice, suggesting B and T cells do not play a major role in the anti-cancer efficacy of ingenol mebutate. Relapse rates were, however, significantly increased in MyD88^-/- mice and in C57BL/6 mice treated with the anti-IL-1 agent, anakinra. Ingenol mebutate treatment induces a pronounced infiltration of neutrophils, which have been shown to have anti-cancer activity in mice. Herein we provide evidence that IL-1 promotes neutrophil recruitment to the tumour, decreases apoptosis of infiltrating neutrophils and increases neutrophil tumour killing activity. These studies suggest IL-1, via its action on neutrophils, promotes the anti-cancer efficacy of ingenol mebutate, with ingenol mebutate treatment causing both IL-1β induction and IL-1α released from keratinocytes.     

Using Superfolder Green Fluorescent Protein for Periplasmic Protein Localization Studies

Studies investigating the subcellular localization of periplasmic proteins have been hampered by problems with the export of green fluorescent protein (GFP). Here we show that a superfolding variant of GFP (sfGFP) is fluorescent following Sec-mediated transport and works best when the cotranslational branch of the pathway is employed.     

Genome-guided exploration of metabolic features of Streptomyces peucetius ATCC 27952: past,current, and prospect

Applied Microbiology and Biotechnology - Streptomyces peucetius ATCC 27952 produces two major anthracyclines, doxorubicin (DXR) and daunorubicin (DNR), which are potent chemotherapeutic agents for...