Instituto de Bioquímica Vegetal y Fotosíntesis IBVF – CIC Cartuja

URI permanente para esta comunidadhttps://hdl.handle.net/11441/10948

Examinar

Mostrando 1 - 5 de 5

Arabidopsis thaliana plastoglobule-associated fibrillin 1a interacts with fibrillin 1b in vivo
(wiley, 2014) Gámez Arjona, Francisco M.; Raynaud, Sandy; Mérida Berlanga, Ángel; Concepción, Juan Carlos de la; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Comisión Interministerial de Ciencia y Tecnología (CICYT). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER)
Plant fibrillins are a well-conserved protein family found in the plastids of all photosynthetic organisms, where they perform a wide range of functions. A number of these proteins have been suggested to be involved in the maintenance of thylakoids and the formation of plastoglobules, preventing their coalescence and favoring their clustering via an as-yet unidentified cross-linking mechanism. In this work we show that two members of this group, namely fibrillin 1a and 1b, interact with each other via a head-to-tail mechanism, thus raising the possibility that they form homo- or hetero-oligomers and providing a mechanism to understand the function of these proteins
Deciphering the function and evolution of the TOR signaling pathway in microalgae
(Oxford University Press, 2022) Mallén Ponce, Manuel J.; Pérez Pérez, Maria Esther; Crespo González, José Luis; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Comisión Interministerial de Ciencia y Tecnología (CICYT). España
Microalgae constitute a highly diverse group of photosynthetic microorganisms that are widely distributed on Earth. The rich diversity of microalgae arose from endosymbiotic events that took place early in the evolution of eukaryotes and gave rise to multiple lineages including green algae, the ancestors of land plants. In addition to their fundamental role as the primary source of marine and freshwater food chains, microalgae are essential producers of oxygen in the planet and a major biotechnological target for sustainable biofuel production and CO2 mitigation. Microalgae integrate light and nutrient signals to regulate cell growth. Recent studies identified the target of rapamycin (TOR) kinase as central regulator of cell growth and nutrient sensor in microalgae. TOR promotes protein synthesis and regulates processes that are induced under nutrient stress such as autophagy and the accumulation of triacylglycerol and starch. A detailed analysis of representative genomes from the entire microalgal lineage revealed the high conservation of central components of the TOR pathway likely present in the last eukaryotic common ancestor and the loss of specific TOR signaling elements at an early stage in the evolution of microalgae. Here we examine the evolutionary conservation of TOR signaling components in diverse microalgae and discuss recent progress on the study of this signaling pathway in these organisms.
Enhancing the expression of starch synthase class IV results in increased levels of both transitory and long-term storage starch
(Wiley Open Access, 2011) Gámez Arjona, Francisco M.; Li, Jun; Raynaud, Sandy; Baroja Fernández, Edurne; Ragel de la Torre, Paula; Mérida Berlanga, Ángel; Universidad de Sevilla. Instituto de Bioquímica Vegetal y Fotosíntesis IBVF – CIC Cartuja; Comisión Interministerial de Ciencia y Tecnología (CICYT). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Junta de Andalucía
Starch is an important renewable raw material with an increasing number of applications.Several attempts have been made to obtain plants that produce modified versions of starchor higher starch yield. Most of the approaches designed to increase the levels of starch havefocused on the increment of the amount of ADP-glucose or ATP available for starch biosyn-thesis. In this work, we show that the overexpression of starch synthase class IV (SSIV)increases the levels of starch accumulated in the leaves ofArabidopsisby 30%–40%. In addi-tion,SSIV-overexpressing lines display a higher rate of growth. The increase in starch contentas a consequence of enhancedSSIVexpression is also observed in long-term storage starchorgans such as potato tubers. Overexpression ofSSIVin potato leads to increased tuber starchcontent on a dry weight basis and to increased yield of starch production in terms of tons ofstarch⁄hectare. These results identify SSIV as one of the regulatory steps involved in the con-trol of the amount of starch accumulated in plastids.
Purification and characterization of an endo-beta-1,6-glucanase from Trichoderma harzianum that is related to its mycoparasitism
(American Society for Microbiology, 1995) Cruz Díaz, Jesús de la; Pintor Toro, José Antonio; Benítez Fernández, Concepción Tahía; Llobell González, Antonio; Comisión Interministerial de Ciencia y Tecnología (CICYT). España; European Commission (EC)
he enzymes from Trichoderma species that degrade fungal cell walls have been suggested to play an important role in mycoparasitic action against fungal plant pathogens. The mycoparasite Trichoderma harzianum produces at least two extracellular beta-1,6-glucanases, among other hydrolases, when it is grown on chitin as the sole carbon source. One of these extracellular enzymes was purified to homogeneity after adsorption to its substrate, pustulan, chromatofocusing, and, finally, gel filtration. The apparent molecular mass was 43,000, and the isoelectric point was 5.8. The first 15 amino acids from the N terminus of the purified protein have been sequenced. The enzyme was specific for beta-1,6 linkages and showed an endolytic mode of action on pustulan. Further characterization indicated that the enzyme by itself releases soluble sugars and produces hydrolytic halli on yeast cell walls. When combined with other T. harzianum cell wall-degrading enzymes such as beta-1,3-glucanases and chitinases, it hydrolyzes filamentous fungal cell walls. The enzyme acts cooperatively with the latter enzymes, inhibiting the growth of the fungi tested. Antibodies against the purified protein also indicated that the two identified beta-1,6-glucanases are not immunologically related and are probably encoded by two different genes
Starch synthase 4 is located in the thylakoid membrane and interacts with plastoglobule-associated proteins in Arabidopsis
(Wiley, 2014) Gámez Arjona, Francisco M.; Raynaud, Sandy; Mérida Berlanga, Ángel; Ragel de la Torre, Paula; Universidad de Sevilla. Departamento de Bioquímica Vegetal y Biología Molecular; Comisión Interministerial de Ciencia y Tecnología (CICYT). España; Junta de Andalucía
Starch synthesis requires the formation of a primer that can be subsequently elongated and branched. How this primer is produced, however, remains unknown. The control of the number of starch granules produced per chloroplast is also a matter of debate. We previously showed starch synthase 4 (SS4) to be involved in both processes, although the mechanisms involved are yet to be fully characterised. The present work shows that SS4 displays a specific localization different from other starch synthases. Thus, this protein is located in specific areas of the thylakoid membrane and interacts with the proteins fibrillin 1a (FBN1a) and 1b (FBN1b), which are mainly located in plastoglobules. SS4 would seem to be associated with plastoglobules attached to the thylakoids (or to that portion of the thylakoids where plastoglobules have originated), forming a complex that includes the FBN1s and other as-yet unidentified proteins. The present results also indicate that the localization pattern of SS4, and its interactions with the FBN1 proteins, are mediated through its N-terminal region, which contains two long coiled-coil motifs. The localization of SS4 in specific areas of the thylakoid membrane suggests that starch granules are originated at specific regions of the chloroplast

Examinar

Examinando Instituto de Bioquímica Vegetal y Fotosíntesis IBVF – CIC Cartuja por Agencia financiadora "Comisión Interministerial de Ciencia y Tecnología (CICYT). España"