Isolation of intact and pure chloroplasts from leaves of Arabidopsis thaliana plants acclimated to low irradiance for studies on Rubisco regulation

A protocol is presented for low-cost and fast isolation of intact and pure chloroplasts from leaves of plants acclimated to low irradiance. The protocol is based on a differential centrifugation of cleared leaf homogenate and omits a centrifugation on Percoll gradient step. The intactness and purity of the chloroplasts isolated from leaves of low irradiance-acclimated plants by using this protocol (confirmed by phase contrast microscopy as well as enzymatic and immunological approaches) allows plausible studies on low irradiance-dependent Rubisco regulation

AtDeg2 – a chloroplast protein with dual protease/chaperone activity

Chloroplast protease AtDeg2 (an ATP-independent serine endopeptidase) is cytosolically synthesized as a precursor, which is imported into the chloroplast stroma and deprived of its transit peptide. Then the mature protein undergoes routing to its functional location at the stromal side of thylakoid membrane. In its linear structure AtDeg2 molecule contains the protease domain with catalytic triad (HDS) and two PDZ domains (PDZ1 and PDZ2). In vivo AtDeg2 most probably exists as a supposedly inactive haxamer, which may change its oligomeric stage to form active 12-mer, or 24-mer. AtDeg2 has recently been demonstrated to exhibit dual protease/chaperone function. This review is focused on the current awareness with regard to AtDeg2 structure and functional significance

Downregulation of chloroplast protease AtDeg5 leads to changes in chronological progression of ontogenetic stages, leaf morphology and chloroplast ultrastructure in Arabidopsis

The chloroplast protein AtDeg5 is a serine-type protease peripherally attached to thylakoid membrane at its lumenal side. Since reliable data regarding the role of AtDeg5 in controlling the course of growth and developmental processes are extremely limited, two independent T-DNA insertional lines with different extent of AtDeg5 reduction were prepared and ontogenesis stage-based analysis performed. Both mutant lines displayed a compensatory overaccumulation of AtDeg8. The repression of AtDeg5 protease altered a range of phenotypic features in at least one of the mutants, with the most prominent being changes in chronological progression of development and growth of individual rosette leaves, flower production and silique ripening as well as in the area of fully expanded leaves and chloroplast ultrastructure. By analyzing the results of parallel-mutant screening we conclude that AtDeg8 overdose may rescue 23% of AtDeg5 deficiency with regard to some AtDeg5-controlled traits; alternatively AtDeg5 may have catalytic sites in excess so that these traits might remain unaltered when AtDeg5 pool is reduced by 23%. For some other AtDeg5-dependent traits the absence of excessive amount of AtDeg5 catalytic sites, lack of AtDeg5 dosage effect and inability of AtDeg8 to compensate deficiency or absence of AtDeg5 occurred

Chronic mesenteric ischaemia: diagnostic and therapeutic difficulties

Chronic mesenteric ischaemia is most often caused by the development of atherosclerosis of two or three mesenteric arteries. Some patients require treatment not only because of significant symptoms, but also because of the potential risk of intestinal necrosis. This study presents the case of a 56-year-old female patient admitted to the Department due to severe abdominal pain, cyclic diarrhoea, and significant weight loss lasting for a period of 1.5 years. Duplex ultrasound and angioCT examinations showed complete occlusion of the proximal segment of the superior mesenteric artery. The patient was qualified to aorto-mesenteric graft surgery below the renal arteries. The segment of the saphenous vein that was used initially did not ensure sufficient circulation in the vicinity of the superior mesenteric artery. The vein was replaced by a PTFE prosthesis of greater diameter, which enabled a good treatment effect. Two years after the operation the patient is asymptomatic, has gained 10 kg, and the prosthesis remains patent - which was confirmed by means of Duplex ultrasound. The Authors mention the often delayed diagnosis in these patients, and need for the individual selection of the therapeutic method. Acta Angiol 2010; 16, 2: 85-92Przewlekłe niedokrwienie jelit jest najczęściej spowodowane rozwojem miażdżycy w obrębie dwóch lub trzech tętnic krezkowych. U części pacjentów konieczne jest leczenie, nie tylko ze względu na znaczne dolegliwości, lecz także z powodu potencjalnego ryzyka martwicy jelit. Opisano przypadek 56-letniej chorej z utrzymującymi się od 1,5 roku silnymi bólami brzucha, okresowymi biegunkami i znaczną utratą masy ciała. W doplerowskim badaniu USG i angiografii CT stwierdzono całkowitą niedrożność początkowego odcinka tętnicy krezkowej górnej. Pacjentkę zakwalifikowano do zabiegu pomostowania aortalno-krezkowego poniżej tętnic nerkowych. Wykorzystany początkowo odcinek żyły odpiszczelowej nie zapewnił wystarczającego krążenia w dorzeczu tętnicy krezkowej górnej. Żyłę zastąpiono protezą PTFE o większej średnicy, uzyskując dobry efekt leczenia. Dwa lata po operacji u chorej nie występują dolegliwości, jej masa ciała zwiększyła się o 10 kg, a w kontrolnym doplerowskim badaniu USG potwierdzono drożność protezy. Autorzy zwracają uwagę na często spóźnione rozpoznanie w tej grupie chorych i potrzebę indywidualnego doboru rodzaju zabiegu. Acta Angiol 2010; 16, 2: 85-9

Chloroplast protease/chaperone AtDeg2 influences cotyledons opening and reproductive development in Arabidopsis

AtDeg2 is a chloroplast protein with dual protease/chaperone activity. Since data on how the individual activities of AtDeg2 affect growth and development of Arabidopsis thaliana plants is missing, two transgenic lines were prepared that express mutated AtDeg2 versions that have either only protease or chaperone activity and a comprehensive ontogenesis stage-based study was performed comprising wild type (WT) plants and insertional mutants that do not express AtDeg2, as well as the two transgenic lines. The repression of both AtDeg2 activities in deg2-3 mutants altered just a few phenotypic traits including the time when cotyledons were fully opened, the time when 10% flowers were open as well as the number of inflorescence branches and seed length in plants which have completed their generative development. It was demonstrated that complete opening of cotyledons as well as the number of inflorescence branches and seed length in plants which have completed their generative development required involvement of both AtDeg2 activities, whereas the time when 10% of flowers were open was controlled by AtDeg2 protease activity. These results show for the first time that the chaperone activity of AtDeg2 is needed for some elements of generative development of A. thaliana plants to proceed normally. So far, the chaperone activity of AtDeg2 was confirmed based on in vitro assays only

Guidelines from the Polish Surgical Society and Polish Society of Oncological Surgery Concerning Quality Assurance for Centres Performing Cytoreductive Procedures and HIPEC Procedures in the Treatment of Primary and Secondary Peritoneal Tumours

Surgical treatment of patients with peritoneal metastases in combination with Hyperthermic intraperitoneal Chemotherapy (HIPEC) and systemic treatments is applied with increasing frequency and, with correct patient qualification, allows for obtaining 5-year survival at a level of 32–52%. The conditions necessary for positive results of such treatment include the high experience of a given centre, its appropriate infrastructure, and appropriate patient qualification for the procedure. As a result of the debate connected with the need to evaluate treatment quality and results, at the request of the Peritoneal Cancer Section of the Polish Society of Oncological Surgery, the conditions for quality assurance were worked out and a Quality Assurance Commission was set up for the centres performing cytoreductive procedures and HIPEC procedures in the treatment of primary and secondary peritoneal tumours

The structure, functions and degradation of pigment-binding proteins of photosystem II

Eleven proteins belonging to photosystem II (PSII) bind photosynthetic pigments in the form of thylakoid membrane-associated pigment-protein complexes. Five of them (PsbA, PsbB, PsbC, PsbD and PsbS) are assigned to PSII core complex while the remaining six (Lhcb1, Lhcb2, Lhcb3, Lhcb4, Lhcb5 and Lhcb6) constitute, along with their pigments, functional complexes situated more distantly with regard to P680 - the photochemical center of PSII. The main function of the pigment-binding proteins is to harvest solar energy and deliver it, in the form of excitation energy, ultimately to P680 although individual pigment-proteins may be engaged in other photosynthesis-related processes as well. The aim of this review is to present the current state of knowledge regarding the structure, functions and degradation of this family of proteins