Isolation, Structural and Biochemical Characterization of Plant PSII-LHCII Supercomplexes

In the first part of this thesis work, they have been investigated the solubilizing properties of \uf061-DM and \uf062-DM on the isolation of photosynthetic complexes from pea thylakoids membranes maintaining their native architecture of stacked grana and stroma lamellae. Exposure of these stacked thylakoids to a single step treatment with increasing concentrations (5\u2013100 mM) of \uf061-DM or \uf062-DM resulted in a quick partial or complete solubilization of the membranes. Regardless of the isomeric form used: 1) at the lowest DM concentrations only a partial solubilization of thylakoids was achieved, giving rise to the release of mainly small protein complexes mixed with membrane fragments enriched in PSI from stroma lamellae; 2) at concentrations above 30 mM a complete solubilization occurred with the further release of high molecular weight protein complexes identified as dimeric PSII, PSI-LHCI and PSII\u2013LHCII supercomplexes. It has been identified in 50 mM of both detrgents the minimal concentration that fully solubilized PSII-LHCII supercomplexes. In the second part of this work they have been characterized, in terms of polypeptide composition, purity and functionality by using biochemical techniques, two forms of PSII-LHCII supercomplexes isolated via sucrose gradient centrifugation from solubilized Pisum sativum thylakoid with 50 mM\uf020\uf061- and \uf062-n-dodecil maltoside. In according to the previous results, to isolate the supercomplexes they have been solubilized directly thylakoids instead of PSII membranes (BBYs), in order to minimize the possibility of detergent-induced artefacts and they have been used stacked membranes in order to avoid destabilization of the interaction of LHCII with the PSII core. The isolated supercomplexes haven\u201ft shown any ATP-ase and PSI contaminations. Both supercomplexes have shown an identical set of LMM subunits. The supercomplex isolated with \uf061-DM was larger and more intact, in terms of OEC and Lhcb subunits, than the supercomplex isolated with \uf062-DM. The supercomplex isolated with \uf061-DM has shown an higher activity than of those isolated with \uf062-DM. In the last part of the work they have been structurally characterized both isolated supercomplexes by using EM single particle analysis. The EM data have shown that the supercomplexes isolated with \uf061-DM was a C2S2M2 while those isolated with \uf062-DM was a C2S2 supercomplex. They have been obtained the 2D projection maps and the 3D reconstructions maps and angular reconstitution at 30 \uc5 (for the C2S2M2) and at 28 \uc5 (for the C2S2)

The role of proline in the adaptation of eukaryotic microalgae to environmental stress: An underestimated tool for the optimization of algal growth

Microalgae are considered the most promising source of renewable fuels, high-value bio-products and nutraceuticals. Potentially, microalgae can satisfy many global demands, but in large-scale cultivation the average productivity of most industrial strains is lower than maximal theoretical estimations, mainly due to sub-optimal growth conditions. Although microalgae have developed complex strategies to cope with environmental stresses, cultivation in outdoor photobioreactors is limited to few species and it is not yet sufficiently remunerative. Indeed, most microalgal species are very sensitive to environmental conditions, and changes in solar irradiation, temperature, and medium composition can drastically decrease biomass yield. Developing new strategies for improving algal tolerance to stress conditions is thus greatly desirable. One of the first responses that occur in both higher plants and microorganisms following the exposure to abiotic stress conditions, is an increased synthesis and accumulation of the amino acid proline. While the role of proline accumulation in stress adaptation is well-recognized in higher plants, in microalgae the implication of proline in stress tolerance still awaits full elucidation. In this review we summarize available data on proline metabolism under environmental stress in eukaryotic microalgae. Possible implications toward optimization of algal growth for biotechnological purposes are also discussed

Effect of lhcsr gene dosage on oxidative stress and light use efficiency by Chlamydomonas reinhardtii cultures

Unicellular green algae, a promising source for renewable biofuels, produce lipid-rich biomass from light and CO2. Productivity in photo-bioreactors is affected by inhomogeneous light distribution from high cell pigment causing heat dissipation of light energy absorbed in excess and shading of the deep layers. Contrasting reports have been published on the relation between photoprotective energy dissipation and productivity. Here, we have re-investigated the relation between energy quenching (qE) activity, photodamage and light use efficiency by comparing WT and two Chlamydomonas reinhardtii strains differing for their complement in LHCSR proteins, which catalyse dissipation of excitation energy in excess (qE). Strains were analysed for ROS production, protein composition, rate of photodamage and productivity assessed under wide light and CO2 conditions.The strain lacking LHCSR1 and knocked down in LHCSR3, thus depleted in qE, produced O-2 at significantly higher rate under high light, accompanied by enhanced singlet oxygen release and PSII photodamage. However, biomass productivity of WT was delayed in respect for mutant strains under intermittent light conditions only, implying that PSII activity was not the limiting factor under excess light. Contrary to previous proposals, domestication of Chlamydomonas for carbon assimilation rate in photo-bioreactors by down-regulation of photoprotective energy dissipation was ineffective in increasing algal biomass productivity

FREQUENCY OF PULMONARY HYPERTENSION IN PATIENTS WITH OBSTRUCTIVE SLEEP APNEA (OSA).

Background; Obstructive sleep apnea (OSA) is commonly complicated by left heart disease and is associated with pulmonary hypertension (PH). This study was done to determine the frequency of pulmonary hypertension in OSA to ascertain current magnitude of the problem. Material and methods: This cross-sectional study was done at Department of Medicine, Nishtar Hospital Multan. A total of 95 patients with OSA were included in this study. Once registered in the study, all the relevant baseline investigations were done like echocargiography to diagnose Pulmonary Hypertension. History was taken like diabetes, hypertension, smoking  and other sociodemographic factors was inquired and statistical analysis was performed by entering all the data in SPSS version 20. Results; Of these 95 study cases, 60 (63.25) were male patients and 35 (26.8%) were female patients. Mean age of our study cases was 36.57 ± 6.06 years. Of these 95 study cases, 20 (21.1%) had diabetes and hypertension was noted in 42 (44.2%) of our study cases. Mean height of our study cases was 156.39 ± 12.92 centimeters while mean weight of our study cases was 74.59 ± 17.27 kilograms. Mean body mass index (BMI) of our study cases was 27.33 ± 4.07 kg/m2 and obesity was present in 40 (42.1%) of our study cases. Mean disease duration was 26.32 ± 10.97 months and history of smoking was present in 21 (22.1%). Pulmonary hypertension was present in 43 (45.3%) of our study cases. Conclusion; Very high frequency of pulmonary hypertension was observed in our study among patients with obstructive sleep apnea. Pulmonary hypertension was significantly associated with diabetes, disease duration, smoking and obesity. All clinicians treating such patients should investigate for pulmonary hypertension for early diagnosis and management which will decrease morbidity and improve quality of life of these patients. Keywords; Obstructive sleep apnea, Pulmonary hypertension, Arterial hypertension

Effect of lhcsr gene dosage on oxidative stress and light use efficiency by Chlamydomonas reinhardtii cultures

Unicellular green algae, a promising source for renewable biofuels, produce lipid-rich biomass from light and CO2. Productivity in photo-bioreactors is affected by inhomogeneous light distribution from high cell pigment causing heat dissipation of light energy absorbed in excess and shading of the deep layers. Contrasting reports have been published on the relation between photoprotective energy dissipation and productivity. Here, we have re-investigated the relation between energy quenching (qE) activity, photodamage and light use efficiency by comparing WT and two Chlamydomonas reinhardtii strains differing for their complement in LHCSR proteins, which catalyse dissipation of excitation energy in excess (qE). Strains were analysed for ROS production, protein composition, rate of photodamage and productivity assessed under wide light and CO2 conditions. The strain lacking LHCSR1 and knocked down in LHCSR3, thus depleted in qE, produced O2 at significantly higher rate under high light, accompanied by enhanced singlet oxygen release and PSII photodamage. However, biomass productivity of WT was delayed in respect for mutant strains under intermittent light conditions only, implying that PSII activity was not the limiting factor under excess light. Contrary to previous proposals, domestication of Chlamydomonas for carbon assimilation rate in photo-bioreactors by down-regulation of photoprotective energy dissipation was ineffective in increasing algal biomass productivity

KARAKTERISTIK PROSES KARBURISASI MENGGUNAKAN LIMBAH SERBUK FOTOCOPY & ARANG BATOK KELAPA PADA BAJA AISI 4140 DENGAN TEMPERATUR 900ºC TERHADAP VARIASI LAJU ALIR GAS

Carburizing (karburasi) adalah suatu proses penambahan lapisan benda kerja dengan karbon melalui perlakuan termokimia. Pada umumnya proses karburasi diikuti dengan quenching (pendinginan cepat) yang dimana untuk meningkatkan kekerasan sehingga permukaan logam menjadi keras atau tahan aus. Pada penelitian ini media karburasi yang digunakan adalah limbah serbuk fotocopy & arang batok kelapa dengan menggunakan material Baja AISI 4140 dan menggunakan dapur fluidized bed furnace. Tujuan utama dari penelitian ini adalah untuk mengetahui apakah serbuk fotocopy & arang batok kelapa dapat meningkatkan kandungan karbon pada Baja AISI 4140 dengan menggunakan proses fluidized bed furnace. Setelah diproses hardening menggunakakn proses carburisasi, untuk mengetahui kadar karbon yang masuk pada spesimen, pada pengujian ini menggunakan uji SEM-EDX. Selain itu juga pengujian ini menggunakan uji kekerasan dan uji keausan untuk mengetahui perbadingan nilai kekerasan dan keausan sebelum di carburisasi dan setelah di carburisasi, dan pada penelitian ini hanya berfokus untuk mengetahui peningkatan kadar karbon, kekerasan, dan penurunan laju keausan pada material yang diteliti. Diharapkan pada penelitian peningkatan kadar karbon, kekerasan dan keausan ini dapat memberikan wawasan, informasi, saran atau masukan penting bagi dunia kerja dan bidang industri, terutama dalam bidang produksi

Potential and challenges of improving photosynthesis in algae

Sunlight energy largely exceeds the energy required by anthropic activities, and therefore its exploitation represents a major target in the field of renewable energies. The interest in the mass cultivation of green microalgae has grown in the last decades, as algal biomass could be employed to cover a significant portion of global energy demand. Advantages of microalgal vs. plant biomass production include higher light‐use efficiency, efficient carbon capture and the valorization of marginal lands and wastewaters. Realization of this potential requires a decrease of the current production costs, which can be obtained by increasing the productivity of the most common industrial strains, by the identification of factors limiting biomass yield, and by removing bottlenecks, namely through domestication strategies aimed to fill the gap between the theoretical and real productivity of algal cultures. In particular, the light‐to‐biomass conversion efficiency represents one of the major constraints for achieving a significant improvement of algal cell lines. This review outlines the molecular events of photosynthesis, which regulate the conversion of light into biomass, and discusses how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. This review highlights the most recent results in the manipulation of the fundamental mechanisms of algal photosynthesis, which revealed that a significant yield enhancement is feasible. Moreover, metabolic engineering of microalgae, focused upon the development of renewable fuel biorefineries, has also drawn attention and resulted in efforts for enhancing productivity of oil or isoprenoids

Biomass from microalgae: The potential of domestication towards sustainable biofactories

Interest in bulk biomass from microalgae, for the extraction of high-value nutraceuticals, bio-products, animal feed and as a source of renewable fuels, is high. Advantages of microalgal vs. plant biomass production include higher yield, use of non-arable land, recovery of nutrients from wastewater, efficient carbon capture and faster development of new domesticated strains. Moreover, adaptation to a wide range of environmental conditions evolved a great genetic diversity within this polyphyletic group, making microalgae a rich source of interesting and useful metabolites. Microalgae have the potential to satisfy many global demands; however, realization of this potential requires a decrease of the current production costs. Average productivity of the most common industrial strains is far lower than maximal theoretical estimations, suggesting that identification of factors limiting biomass yield and removing bottlenecks are pivotal in domestication strategies aimed to make algal-derived bio-products profitable on the industrial scale. In particular, the light-to-biomass conversion efficiency represents a major constraint to finally fill the gap between theoretical and industrial productivity. In this respect, recent results suggest that significant yield enhancement is feasible. Full realization of this potential requires further advances in cultivation techniques, together with genetic manipulation of both algal physiology and metabolic networks, to maximize the efficiency with which solar energy is converted into biomass and bio-products. In this review, we draft the molecular events of photosynthesis which regulate the conversion of light into biomass, and discuss how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. We outline major successes reached, and promising strategies to achieving significant contributions to future microalgae-based biotechnology

Mediterranean Diet and Healthy Ageing: A Sicilian Perspective

Traditional Mediterranean diet (MedDiet) is a common dietary pattern characterizing a lifestyle and culture proven to contribute to better health and quality of life in Mediterranean countries. By analyzing the diet of centenarians from the Sicani Mountains and eating habits of inhabitants of Palermo, it is reported that a close adherence to MedDiet is observed in the countryside, whereas in big towns this adherence is not so close. This has an effect on the rates of mortality at old age (and reciprocally longevity) that are lower in the countryside than in big towns. Concerning the health effects of the diet, the low content of animal protein and the low glycaemic index of the Sicilian MedDiet might directly modulate the insulin/IGF-1 and the mTOR pathways, known to be involved in ageing and longevity. In particular, the reduction of animal protein intake may significantly reduce serum IGF-1 concentrations and inhibit mTOR activity with a down-regulation of the signal that leads to the activation of FOXO3A and, consequently, to the transcription of homeostatic genes that favour longevity. The down-regulation of both IGF-1 and mTORC1 also induces an anti-inflammatory effect. In addition to the effects on sensing pathways, many single components of MedDiet are known to have positive effects on health, reducing inflammation, optimizing cholesterol and other important risk factors of age-related diseases. However, a key role is played by polyphenols represented in high amount in the Sicilian MedDiet (in particular in extra virgin olive oil) that can work as hormetins that provide an environmental chemical signature regulating stress resistance pathways such as nuclear factor erythroid 2-related factor 2

Overlapping Presence of Macroamylasemia and Hyperamylasemia in Acute Pancreatitis

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