Identification and characterization of antibacterial compound(s) of cockroaches (Periplaneta americana)

Infectious diseases remain a significant threat to human health, contributing to more than 17 million deaths, annually. With the worsening trends of drug resistance, there is a need for newer and more powerful antimicrobial agents. We hypothesized that animals living in polluted environments are potential source of antimicrobials. Under polluted milieus, organisms such as cockroaches encounter different types of microbes, including superbugs. Such creatures survive the onslaught of superbugs and are able to ward off disease by producing antimicrobial substances. Here, we characterized antibacterial properties in extracts of various body organs of cockroaches (Periplaneta americana) and showed potent antibacterial activity in crude brain extract against methicillin-resistant Staphylococcus aureus and neuropathogenic E. coli K1. The size-exclusion spin columns revealed that the active compound(s) are less than 10 kDa in molecular mass. Using cytotoxicity assays, it was observed that pre-treatment of bacteria with lysates inhibited bacteria-mediated host cell cytotoxicity. Using spectra obtained with LC-MS on Agilent 1290 infinity liquid chromatograph, coupled with an Agilent 6460 triple quadruple mass spectrometer, tissues lysates were analyzed. Among hundreds of compounds, only a few homologous compounds were identified that contained isoquinoline group, chromene derivatives, thiazine groups, imidazoles, pyrrole containing analogs, sulfonamides, furanones, flavanones, and known to possess broad-spectrum antimicrobial properties, and possess anti-inflammatory, anti-tumour, and analgesic properties. Further identification, characterization and functional studies using individual compounds can act as a breakthrough in developing novel therapeutics against various pathogens including superbugs

Otrzymywanie i właściwosci dielektryczne ceramiki 0,7BiFeO3-0,3BaTiO3

In a present paper results of the process of synthesis and study of a perovskite-type solid solution of the chemical composition (1-x)BiFeO3-xBaTiO3 for x=0.3 are reported. Synthesis of 0.7BiFeO3-0.3BaTiO3 (BF-BT) ceramics was carried out according to the solid-phase reaction from the mixture of powders. Simultaneous thermal analysis (STA) and X-ray diffraction method were utilized to study the synthesis of BF-BT ceramics. On the basis of STA analysis the optimum conditions of the thermal treatment were found. BF-BT ceramics was studied in terms of its microstructure (SEM), chemical composition (EDS), crystalline structure (XRD), and dielectric properties (impedance spectroscopy) at room temperature. It was found that dense BF-BT ceramics with a cubic structure of Pm3m space group and desired stoichiometry (š3%) was fabricated under technological conditions differing in both sintering temperature (T=750°C-850°C) and soaking time (t=2h-40h). It was found that an increase in sintering temperature for ?T=100°C made it possible to decrease the soaking time 10 times. Impedance spectroscopy was utilized for characterizing dynamical dielectric properties of 0.7BF-0.3BT ceramics. The alternative representation of impedance data in a form of complex plot (Z" vs. Z') as well as simultaneous Bode plots (imaginary parts of impedance Z", admittance Y", electric modulus M" and tan versus frequency in a log-log scale) were used for preliminary visual analysis. Kramers-Kronig transform test was utilized for experimental data validation. To analyze the room temperature impedance spectroscopy data complex nonlinear least squares fitting method was used and the data were fitted to the corresponding equivalent circuit consisting of resistors and constant phase elements. Agreement between experimental and simulated data was established.W niniejszej pracy przedstawiono rezultaty badań poświęconych wytwarzaniu i charakterystyce właściwosci roztworu stałego o strukturze typu perowskitu i składzie chemicznym (1-x)BiFeO3–xBaTiO3 dla x=0,3. Proces syntezy ceramiki 0,7BiFeO3–0,3BaTiO3 (BF-BT) przeprowadzono w wyniku reakcji w fazie stałej z mieszaniny prostych tlenków. Przy pomocy analizy termicznej (STA) oraz rentgenowskiej analizy strukturalnej dokonano charakterystyki procesu syntezy ceramiki BF-BT. Przeprowadzono badania mikrostruktury ceramiki BF-BT za pomoca skaningowego mikroskopu elektronowego (SEM), określono stechiometrie składu chemicznego przy użyciu metody EDS, a strukture krystaliczna badano metoda dyfrakcji rentgenowskiej (RTG). Przeprowadzono badania właściwosci dielektyrcznych wytworzonej ceramiki metodą spektroskopii impedancyjnej. Wykorzystując metodę swobodnego spiekania dla trzech różnych warunków technologicznych (T=750-880 C, t=2-40h) otrzymano ceramike 0,7BF–0,3BT o dużej czystości i homogenicznosci składu (3%), wykazujaca strukture regularna Pm3m. Na podstawie przeprowadzonych badań stwierdzono, iż zwiększenie temperatury syntezy i spiekania o T=100 C, pozwoliło zmniejszyć czas wytrzymania ceramiki 10 razy. Badania przeprowadzone metoda spektroskopii impedancyjnej pozwoliły na scharakteryzowanie właściwosci dielektrycznych ceramiki 0,7BF–0,3BT. Dane impedancyjne przedstawiono w płaszczyznie zespolonej Z" od Z' oraz w postaci zależności częstotliwościowych urojonych składowych impedancji Z"(v), modułu elektrycznego M"0(v), admitancji Y"(v) i strat dielektrycznych tg(v). Spójność danych pomiarowych sprawdzono przy pomocy metodyki Kramersa-Kroniga, która potwierdziła poprawność danych eksperymentalnych

Endothelial adhesion molecules contribution to lenkocyte recruitment into inflamed tissues

Adhesion of cells to each other and to the extracellular matrix is crucial for multicellular organisms in development and in the normal functioning of the immune system. One of the most studied aspects of cell adhesion is the accumulation of leukocytes in inflammation, an essential process for effective host defense against infection and injury. On their way to sites of antigen challenge (microbial invasion, transplanted tissue, vaccine deposit) circulating in blood leukocytes must adhere to the endothelium lining the postcapillary venules, penetrate the vessel wall and migrate to the site of tissue irritation. At each of these stages, specific adhesive interactions between leukocytes and the vessel wall (and subsequently the extracellular matrix) are important. This sequence of events can be vieved as a cascade reaction similar to the complement and coagulation cascades

Endothelial adhesion molecules contribution to lenkocyte recruitment into inflamed tissues

Adhesion of cells to each other and to the extracellular matrix is crucial for multicellular organisms in development and in the normal functioning of the immune system. One of the most studied aspects of cell adhesion is the accumulation of leukocytes in inflammation, an essential process for effective host defense against infection and injury. On their way to sites of antigen challenge (microbial invasion, transplanted tissue, vaccine deposit) circulating in blood leukocytes must adhere to the endothelium lining the postcapillary venules, penetrate the vessel wall and migrate to the site of tissue irritation. At each of these stages, specific adhesive interactions between leukocytes and the vessel wall (and subsequently the extracellular matrix) are important. This sequence of events can be vieved as a cascade reaction similar to the complement and coagulation cascades