Downregulation of pyrophosphate: d-fructose-6-phosphate 1-phosphotransferase activity in sugarcane culms enhances sucrose accumulation due to elevated hexose-phosphate levels

Analyses of transgenic sugarcane clones with 45–95% reduced cytosolic pyrophosphate: d-fructose-6-phosphate 1-phosphotransferase (PFP, EC 2.7.1.90) activity displayed no visual phenotypical change, but significant changes were evident in in vivo metabolite levels and fluxes during internode development. In three independent transgenic lines, sucrose concentrations increased between three- and sixfold in immature internodes, compared to the levels in the wildtype control. There was an eightfold increase in the hexose-phosphate:triose-phosphate ratio in immature internodes, a significant restriction in the triose phosphate to hexose phosphate cycle and significant increase in sucrose cycling as monitored by 13C nuclear magnetic resonance. This suggests that an increase in the hexose-phosphate concentrations resulting from a restriction in the conversion of hexose phosphates to triose phosphates drive sucrose synthesis in the young internodes. These effects became less pronounced as the tissue matured. Decreased expression of PFP also resulted in an increase of the ATP/ADP and UTP/UDP ratios, and an increase of the total uridine nucleotide and, at a later stage, the total adenine nucleotide pool, revealing strong interactions between PPi metabolism and general energy metabolism. Finally, decreased PFP leads to a reduction of PPi levels in older internodes indicating that in these developmental stages PFP acts in the gluconeogenic direction. The lowered PPi levels might also contribute to the absence of increases in sucrose contents in the more mature tissues of transgenic sugarcane with reduced PFP activity

Projektowanie i technologia wielowarstwowych hybrydowych układów eletronicznych

The design and technology of hybrid electronic ceramic circuits with flip-chip and SMD (Surface Mounting Device) components are presented in the paper. The flip-chip audio amplifier and RF (Radio Frequency) transmitting and receiving modules are fabricated using LTCC (Low Temperature Co-fired Ceramics). X-Ray inspection is performed to analyze the solder bonding quality. The application of special underfill has increased the reliability of interconnections between flip-chip, SMD components and the ceramic multilayer substrate. The final structure of the audio amplifier module is encapsulated with ceramic housing.W pracy zaprezentowano projekt oraz realizację dwóch przykładowych hybrydowych układów elektronicznych: wzmacniacza audio opartego na elemencie typu flip- -chip oraz nadajnika i odbiornika RF opartych na elementach do montażu powierzch-niowego (SMD). Przedstawione układy zostały wykonane przy wykorzystaniu techno-logii bazującej na niskotemperaturowej ceramice współwypalanej (LTCC). Niezawod-ność połączeń lutowanych pomiędzy elementem typu flip-chip a polami kontaktowymi umieszczonymi na podłożu LTCC zbadano za pomocą metody rentgenowskiej. Poprawę niezawodności w przypadku układu z elementem typu flip-chip uzyskano stosując wypełnienie organiczne pomiędzy chipem a podłożem. Gotowy układ wzmacniacza audio zamknięto w specjalnie przygotowanej obudowie ceramicznej