Positioning of nuclei in the secondary mycelium of Schizophyllum commune in relation to differential gene expression

In this paper we propose a novel type of gene regulation in the MATA not equal MATB not equal heterokaryon of Schizophyllum commune by means of differential positioning of the nuclei. It was found that binucleate hyphae with juxtaposed nuclei secrete SC4 hydrophobin (abundant during fruit-body formation), while SC3 (abundant during aerial hyphae formation in both mono- and dikaryons) appeared to be absent. Certain growth conditions disrupted the binucleate state in that the compatible nuclei became separated at a considerable distance. Under these conditions SC4 was not secreted while SC3 was secreted to a high degree. Disruption of the binucleate state was earlier observed in developing aerial hyphae which secrete SC3. Apparently when the nuclei are in close proximity the dikaryon-expressed genes are switched on by interaction of the products of the MATA and MATB mating-type genes, while SC3 is suppressed by interacting products of the MATB genes, as occurs in the common MATA heterokaryon (MATA = MATB not equal). Growth conditions that lead to disruption of the binucleate state apparently result in abolishment of interaction between the MATB mating-type genes, Under these conditions, dikaryon-specific mRNAs do not accumulate in the MATA not equal MATB not equal heterokaryon, while SC3 mRNA becomes highly abundant. (C) 1998 Academic Press

MEMS tunable capacitors and switches for RF applications

RF MEMS capacitive switches and tunable capacitors have been realized in an industrialized thin-film process developed for manufacturing high-quality inductors and capacitors. Combining integrated passives with high-performance tuning and switching elements on the same die offers a potential for building a new generation of RF front-ends for hand-held mobile communication. Capacitive switches with an insertion loss of 0.4 dB and an isolation of 17 dB at 1 GHz have been demonstrated. Dual-gap relay type tunable capacitors have been fabricated that show a continuous and reversible tuning ratio of 12 together with a quality factor larger than 150 at frequencies higher than 0.5 GHz. These are the highest tuning ratio and quality factor reported to date. A 0-level packaging concept that is compatible with the fabrication technology has been adopted