scholarly journals Changes of Photosynthetic Behaviors inKappaphycus alvareziiInfected by Epiphyte

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Tong Pang ◽  
Jianguo Liu ◽  
Qian Liu ◽  
Wei Lin
Keyword(s):  
Photosynthetic Activity ◽  
Oxygen Evolving Complex ◽  
Morphological Studies ◽  
Active Reaction ◽  
Performance Indexes ◽  
Chlorophyll Fluorescence Transient ◽  
Oxygen Evolving ◽  
Harmful Effects

Epiphytic filamentous algae (EFA) were noted as a serious problem to reduce the production and quality ofK. alvarezii. The morphological studies revealed that the main epiphyte onK. alvareziiwasNeosiphonia savatieriin China. Though the harmful effects of EFA on the production ofK. alvareziihave been reported, the detailed mechanism of theN. savatieriin limiting the production ofK. alvareziihas not been studied yet. The present paper studied the effects ofN. savatieriinfection on photosynthetic behaviors inK. alvareziiby detecting chlorophyll fluorescence transient in vivo. The results revealed that damage of oxygen-evolving complex (OEC), decrease of active reaction centers (RCs), and the plastoquinone (PQ) pool as well as significant reduction in the performance indexes (PI) of PSII were caused by the infection ofN. savatieri. The influence ofN. savatierion photosynthetic activity ofK. alvareziishould be one of the important reasons to reduce the production ofK. alvareziiinfected byN. savatieri.

Photoacclimation involves modulation of the photosynthetic oxygen-evolving reactions in Dunaliella tertiolecta and Phaeodactylum tricornutum

2003 ◽  
Vol 30 (3) ◽  
pp. 301 ◽  
Author(s):  
Antonietta Quigg ◽  
John Beardall ◽  
Tom Wydrzynski
Keyword(s):  
Phaeodactylum Tricornutum ◽  
Higher Plants ◽  
Dunaliella Tertiolecta ◽  
Oxygen Evolving Complex ◽  
Net Energy ◽  
Photosynthetic Physiology ◽  
Oxygen Flash ◽  
Species Specific ◽  
Oxygen Evolving

Net energy accumulation by marine microalgae at very low photon fluxes involves modulation of several attributes related to both the growth and photosynthetic physiology of these organisms. Here we studied flash-induced oscillatory patterns in oxygen evolution by previously dark-adapted cells of the green alga Dunaliella tertiolecta (Butcher) and the diatom Phaeodactylum tricornutum (Bohlin). The activity of the oxygen-evolving complex was found to be species-specific and influenced by photoacclimation. Results from measurements of oxygen flash yield obtained for these organisms grown under light-saturating conditions are directly comparable to those previously reported in the literature for other microalgae and higher plants. However, similar measurements on cells grown in low-light and/or light-starved conditions indicate an increased level of backward transitions (double misses) leading to the formation of super-reduced states (i.e. S–1 and S–2). Thus, in this communication, we present the first evidence that super-reduced states can be generated in vivo and speculate, on how they may be physiologically important.

Quantitative assessment of the high-light tolerance in plants with an impaired photosystem II donor side

2019 ◽  
Vol 476 (9) ◽  
pp. 1377-1386 ◽  
Author(s):  
Sam Wilson ◽  
Alexander V. Ruban
Keyword(s):  
Photosystem Ii ◽  
Redox State ◽  
Photochemical Quenching ◽  
Oxygen Evolving Complex ◽  
Reaction Centre ◽  
Donor Side ◽  
Acceptor Side ◽  
Oxygen Evolving ◽  
The Impact

Abstract Photoinhibition is the light-induced down-regulation of photosynthetic efficiency, the primary target of which is photosystem II (PSII). Currently, there is no clear consensus on the exact mechanism of this process. However, it is clear that inhibition can occur through limitations on both the acceptor- and donor side of PSII. The former mechanism is caused by electron transport limitations at the PSII acceptor side. Whilst, the latter mechanism relies on the disruption of the oxygen-evolving complex. Both of these mechanisms damage the PSII reaction centre (RC). Using a novel chlorophyll fluorescence methodology, RC photoinactivation can be sensitively measured and quantified alongside photoprotection in vivo. This is achieved through estimation of the redox state of QA, using the parameter of photochemical quenching in the dark (qPd). This study shows that through the use of PSII donor-side inhibitors, such as UV-B and Cd2+, there is a steeper gradient of photoinactivation in the systems with a weakened donor side, independent of the level of NPQ attained. This is coupled with a concomitant decline in the light tolerance of PSII. The native light tolerance is partially restored upon the use of 1,5-diphenylcarbazide (DPC), a PSII electron donor, allowing for the balance between the inhibitory pathways to be sensitively quantified. Thus, this study confirms that the impact of donor-side inhibition can be detected alongside acceptor-side photoinhibition using the qPd parameter and confirms qPd as a valid, sensitive and unambiguous parameter to sensitively quantify the onset of photoinhibition through both acceptor- or donor-side mechanisms.

Chemical reduction of graphene enhances in vivo translocation and photosynthetic inhibition in pea plants

2019 ◽  
Vol 6 (4) ◽  
pp. 1077-1088 ◽  
Author(s):  
Lingyun Chen ◽  
Chenglong Wang ◽  
Shengnan Yang ◽  
Xin Guan ◽  
Qiangqiang Zhang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Photosystem Ii ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Oxygen Evolving Complex ◽  
Donor Side ◽  
Photosynthetic Inhibition ◽  
Reduced Graphene ◽  
Oxygen Evolving

Reduced graphene oxide (RGO) was translocated into leaves and inhibited the activity of photosystem II by damaging the oxygen-evolving-complex on the donor side.

scholarly journals Addressing the Need of a Translational Approach in Peripheral Neuropathy Research: Morphology Meets Function

2021 ◽  
Vol 11 (2) ◽  
pp. 139
Author(s):  
Laura Monza ◽  
Giulia Fumagalli ◽  
Alessia Chiorazzi ◽  
Paola Alberti
Keyword(s):  
Feasible Solution ◽  
Common Disease ◽  
Clinical Protocol ◽  
Hospital Department ◽  
Morphological Studies ◽  
Simple Protocol ◽  
F Wave ◽  
Translational Approach

Peripheral neuropathies (PNs) are a type of common disease that hampers the quality of life of affected people. Treatment, in most cases, is just symptomatic and often ineffective. To improve drug discovery in this field, preclinical evidence is warranted. In vivo rodent models allow a multiparametric approach to test new therapeutic strategies, since they can allow pathogenetic and morphological studies different from the clinical setting. However, human readouts are warranted to promptly translate data from the bench to the bedside. A feasible solution would be neurophysiology, performed similarly at both sides. We describe a simple protocol that reproduces the standard clinical protocol of a neurophysiology hospital department. We devised the optimal montage for sensory and motor recordings (neurography) in mice, and we also implemented F wave testing and a short electromyography (EMG) protocol at rest. We challenged this algorithm by comparing control animals (BALB/c mice) with a model of mild neuropathy to grasp even subtle changes. The neurophysiological results were confirmed with neuropathology. The treatment group showed all expected alterations. Moreover, the neurophysiology matched the neuropathological analyses. Therefore, our protocol can be suggested to promptly translate data from the bench to the bedside and vice versa.

Shall I trust you? From child human-robot interaction to trusting relationships

2019 ◽  
Author(s):  
Cinzia Di Dio ◽  
Federico Manzi ◽  
Giulia Peretti ◽  
Angelo Cangelosi ◽  
Paul L. Harris ◽  
...  
Keyword(s):  
Behavioral Pattern ◽  
Human Robot Interaction ◽  
School Age Children ◽  
Social Relevance ◽  
Robot Interaction ◽  
Cognitive Correlates ◽  
The Social ◽  
The Relationship

Studying trust within human-robot interaction is of great importance given the social relevance of robotic agents in a variety of contexts. We investigated the acquisition, loss and restoration of trust when preschool and school-age children played with either a human or a humanoid robot in-vivo. The relationship between trust and the quality of attachment relationships, Theory of Mind, and executive function skills was also investigated. No differences were found in children’s trust in the play-partner as a function of agency (human or robot). Nevertheless, 3-years-olds showed a trend toward trusting the human more than the robot, while 7-years-olds displayed the reverse behavioral pattern, thus highlighting the developing interplay between affective and cognitive correlates of trust.

scholarly journals Structural Changes in the Acceptor Site of Photosystem II upon Ca2+/Sr2+ Exchange in the Mn4CaO5 Cluster Site and the Possible Long-Range Interactions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 371
Author(s):  
Koua
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Long Range ◽  
Electron Acceptor ◽  
Structural Changes ◽  
Acceptor Site ◽  
Oxygen Evolving Complex ◽  
Long Range Interactions ◽  
Structural Perturbations ◽  
Oxygen Evolving

The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites.

scholarly journals Influence of calcium ion-modified implant surfaces in protein adsorption and implant integration

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Eduardo Anitua ◽  
Andreia Cerqueira ◽  
Francisco Romero-Gavilán ◽  
Iñaki García-Arnáez ◽  
Cristina Martinez-Ramos ◽  
...  
Keyword(s):  
Protein Adsorption ◽  
Titanium Implant ◽  
Volume Density ◽  
Bone Implant ◽  
The Mean ◽  
Intervention Costs ◽  
Medial Section ◽  
Post Implantation

Abstract Background Calcium (Ca) is a well-known element in bone metabolism and blood coagulation. Here, we investigate the link between the protein adsorption pattern and the in vivo responses of surfaces modified with calcium ions (Ca-ion) as compared to standard titanium implant surfaces (control). We used LC–MS/MS to identify the proteins adhered to the surfaces after incubation with human serum and performed bilateral surgeries in the medial section of the femoral condyles of 18 New Zealand white rabbits to test osseointegration at 2 and 8 weeks post-implantation (n=9). Results Ca-ion surfaces adsorbed 181.42 times more FA10 and 3.85 times less FA12 (p<0.001), which are factors of the common and the intrinsic coagulation pathways respectively. We also detected differences in A1AT, PLMN, FA12, KNG1, HEP2, LYSC, PIP, SAMP, VTNC, SAA4, and CFAH (p<0.01). At 2 and 8 weeks post-implantation, the mean bone implant contact (BIC) with Ca-ion surfaces was respectively 1.52 and 1.25 times higher, and the mean bone volume density (BVD) was respectively 1.35 and 1.13 times higher. Differences were statistically significant for BIC at 2 and 8 weeks and for BVD at 2 weeks (p<0.05). Conclusions The strong thrombogenic protein adsorption pattern at Ca-ion surfaces correlated with significantly higher levels of implant osseointegration. More effective implant surfaces combined with smaller implants enable less invasive surgeries, shorter healing times, and overall lower intervention costs, especially in cases of low quantity or quality of bone.

Animal Models and Alternatives in the Quality Control of Vaccines: Are In Vitro Methods or In Vivo Methods the Scientific Equivalent of the Emperor's New Clothes?

1995 ◽  
Vol 23 (1) ◽  
pp. 61-73
Author(s):  
Coenraad Hendriksen ◽  
Johan van der Gun
Keyword(s):  
Quality Control ◽  
Test Methods ◽  
In Vitro Test ◽  
Large Numbers ◽  
Alternative Approach ◽  
Inactivated Vaccines ◽  
Vitro Test

In the quality control of vaccine batches, the potency testing of inactivated vaccines is one of the areas requiring very large numbers of animals, which usually suffer significant distress as a result of the experimental procedures employed. This article deals with the potency testing of diphtheria and tetanus toxoids, two vaccines which are used extensively throughout the world. The relevance of the potency test prescribed by the European Pharmacopoeia monographs is questioned. The validity of the potency test as a model for the human response, the ability of the test to be standardised, and the relevance of the test in relation to the quality of the product are discussed. It is concluded that the potency test has only limited predictive value for the antitoxin responses to be expected in recipients of these toxoids. An alternative approach for estimating the potency of toxoid batches is discussed, in which a distinction is made between estimation of the immunogenic potency of the first few batches obtained from a seed lot and monitoring the consistency of the quality of subsequent batches. The use of animals is limited to the first few batches. Monitoring the consistency of the quality of subsequent batches is based on in vitro test methods. Factors which hamper the introduction and acceptance of the alternative approach are considered. Finally, proposals are made for replacement, reduction and/or refinement (the Three Rs) in the use of animals in the routine potency testing of toxoids.

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