Polyprenols Are Synthesized by a Plastidial cis-Prenyltransferase and Influence Photosynthetic Performance

Plants accumulate a family of hydrophobic polymers known as polyprenols, yet how they are synthesized, where they reside in the cell, and what role they serve is largely unknown. Using Arabidopsis thaliana as a model, we present evidence for the involvement of a plastidial cis-prenyltransferase (AtCPT7) in polyprenol synthesis. Gene inactivation and RNAi-mediated knockdown of AtCPT7 eliminated leaf polyprenols, while its overexpression increased their content. Complementation tests in the polyprenol-deficient yeast Δrer2 mutant and enzyme assays with recombinant AtCPT7 confirmed that the enzyme synthesizes polyprenols of ~55 carbons in length using geranylgeranyl diphosphate (GGPP) and isopentenyl diphosphate as substrates. Immunodetection and in vivo localization of AtCPT7 fluorescent protein fusions showed that AtCPT7 resides in the stroma of mesophyll chloroplasts. The enzymatic products of AtCPT7 accumulate in thylakoid membranes, and in their absence, thylakoids adopt an increasingly “fluid membrane” state. Chlorophyll fluorescence measurements from the leaves of polyprenol-deficient plants revealed impaired photosystem II operating efficiency, and their thylakoids exhibited a decreased rate of electron transport. These results establish that (1) plastidial AtCPT7 extends the length of GGPP to;55 carbons, which then accumulate in thylakoid membranes; and (2) these polyprenols influence photosynthetic performance through their modulation of thylakoid membrane dynamics

Biallelic VARS variants cause developmental encephalopathy with microcephaly that is recapitulated in vars knockout zebrafish

Aminoacyl tRNA synthetases (ARSs) link specific amino acids with their cognate transfer RNAs in a critical early step of protein translation. Mutations in ARSs have emerged as a cause of recessive, often complex neurological disease traits. Here we report an allelic series consisting of seven novel and two previously reported biallelic variants in valyl-tRNA synthetase (VARS) in ten patients with a developmental encephalopathy with microcephaly, often associated with early-onset epilepsy. In silico, in vitro, and yeast complementation assays demonstrate that the underlying pathomechanism of these mutations is most likely a loss of protein function. Zebrafish modeling accurately recapitulated some of the key neurological disease traits. These results provide both genetic and biological insights into neurodevelopmental disease and pave the way for further in-depth research on ARS related recessive disorders and precision therapies

Ovaries of Tubificinae (Clitellata, Naididae) resemble ovary cords found in Hirudinea (Clitellata)

The ultrastructure of the ovaries and oogenesis was studied in three species of three genera of Tubificinae. The paired ovaries are small, conically shaped structures, connected to the intersegmental septum between segments X and XI by their narrow end. The ovaries are composed of syncytial cysts of germ cells interconnected by stable cytoplasmic bridges (ring canals) and surrounded by follicular cells. The architecture of the germ-line cysts is exactly the same as in all clitellate annelids studied to date, i.e. each cell in a cyst has only one ring canal connecting it to the central, anuclear cytoplasmic mass, the cytophore. The ovaries found in all of the species studied seem to be meroistic, i.e. the ultimate fate of germ cells within a cyst is different, and the majority of cells withdraw from meiosis and become nurse cells; the rest continue meiosis, gather macromolecules, cell organelles and storage material, and become oocytes. The ovaries are polarized; their narrow end contains mitotically dividing oogonia and germ cells entering the meiosis prophase; whereas within the middle and basal parts, nurse cells, a prominent cytophore and growing oocytes occur. During late previtellogenesis/early vitellogenesis, the oocytes detach from the cytophore and float in the coelom; they are usually enveloped by the peritoneal epithelium and associated with blood vessels. Generally, the organization of ovaries in all of the Tubificinae species studied resembles the polarized ovary cords found within the ovisacs of some Euhirudinea. The organization of ovaries and the course of oogenesis between the genera studied and other clitellate annelids are compared. Finally, it is suggested that germ-line cysts formation and the meroistic mode of oogenesis may be a primary character for all Clitellata

Methods and software tools of Integrated Communication Systems diagnostics on the aircraft board

Artykuł przedstawia narzędzia badawcze wykorzystywane w Instytucie Technicznym Wojsk Lotniczych do uruchomienia, testowania i diagnozowania zintegrowanych systemów łączności (ZSŁ) w zakresie zestawu radiostacji pokładowych (lotniczych i taktycznych) oraz funkcji wykorzystanego w nich oprogramowania na pokładzie statku powietrznego. Problem badawczy podejmowany w artykule określony został poprzez opracowanie i budowę stanowiska integracyjnego przeznaczonego do uruchamiania radiostacji pokładowych integrowanych na bazie cyfrowych szyn danych (m.in. wg standardu MIL-1553B) oraz mobilnego zestawu aparatury kontrolno-diagnostycznej przeznaczonej do przygotowania planów radiowych, przeniesienia ich na pokład oraz diagnozowania poszczególnych radiostacji zintegrowanego systemu łączności w czasie ich eksploatacji. Pokładowa sieć wymiany danych, całe oprogramowanie integracyjne dla poszczególnych radiostacji oraz architektura i organizacja systemu łączności radiowej m.in. serwera komunikacyjnego została opracowana przez Zakład Awioniki ITWL. Stanowisko integracyjne oraz zestaw aparatury kontrolno-diagnostycznej pozwala integrować nowoczesne radiostacje pokładowe oraz urządzenia zintegrowanych systemów łączności radiowej na pokładzie śmigłowców wojskowych m.in. z rodziny Mi oraz W-3PL „Głuszec”. Przedstawiono wybrane zadania realizowane za pomocą tego stanowiska oraz problemy pojawiające się podczas uruchamiania i testowania opracowanego oprogramowania integrującego urządzenia łączności w zakresie jego funkcjonalności i niezawodności. Zastosowanie komputerowego systemu diagnozowania umożliwia wprowadzenie zmian w oprogramowaniach poszczególnych radiostacji, zmianę ustawień parametrów technicznych oraz automatyczne wykrywanie niesprawności w bieżącej eksploatacji zintegrowanego systemu łączności, którego głównym elementem jest serwer komunikacyjny. Omówione narzędzia diagnostyczne pozwalają integrować nowoczesne radiostacje pokładowe stosowane w lotnictwie wojskowym, wspomagają także proces diagnozowania i testowania nowych urządzeń radiokomunikacyjnych oraz stanową bazę do dalszego rozwoju zintegrowanych systemów łączności. Posiadanie takiego stanowiska integracyjnego oraz aparatury kontrolno-diagnostycznej pozwala uzyskać możliwości firm zachodnich w zakresie integrowania nowych urządzeń łączności na współczesnym poziomie technologicznym oraz diagnostyki technicznej systemów.The article presents research methods which are utilized at the Air Force Institute of Technology, to start, test and diagnose integrated communication systems in the scope of the set of radios (aerial and tactical) and functions realized by their software on board the aircraft. The research problem presented in this article was characterized through work out and construction of the integration station, which is designed to activate aircraft radios integrated on the base of the digital data buses (e.g. according to MIL-1553B) and through the mobile testing and diagnostic equipment set which is used to prepare radio plans and then transport them to the aircraft, moreover to diagnose aircraft radios from integrated communication system during maintenance. On board data transfer net, the whole integration software for the particular radios and the architecture and organization of the radio communication system, e.g. communication server’s architecture, was elaborated at the Division for Avionics, AFIT. The integration station and testing-diagnostic equipment enable us to integrate modern aircraft radios and elements of integrated communication systems on board of the military helicopters, e.g. “Mi” family helicopters and W-3PL “Głuszec” helicopter. There are presented selected tasks realized by this station and some problems connected with the activation and testing of the prepared software which integrates communication equipment concerning functionality and reliability of its operation. Application of computer diagnostics system enables the operator to make a correction, improvement in particular radio’s software, change the technical parameters and automatic detection of failures during basic maintenance of integrated communication system, which main element is a communication server. Diagnostic methods presented in this article allow us to integrate modern aircraft radio sets used in the Air Force, assist the process of diagnosing and testing of modern radio-communication equipment and offer a solid base for further development of integrated communication systems. Possession of such an integration station and testing-diagnostic equipment set enables us to reach the capabilities of western companies considering modern communication devices integration with respect to the current technological know-how and up-to-date technical systems’ diagnostics aspects