Chloroplast PSII photochemical efficiency is upregulated more rapidly than CO2 assimilation during photosynthesis induction, suggesting the existence of other electron sinks than that of CO2 assimilation. We hypothesized that the mitochondrial alternative oxidase (AOX) pathway could be such a sink. Inhibition of the AOX restricted light activation of the malate-oxaloacetate shuttle and caused an excessive reduction of PSI acceptor side and substantial accumulation of QA-, hindering the photosynthetic linear electron transport rate (ETR) and leading to an imbalance between light energy absorption and exploitation during photosynthetic induction. ETR limitation also restricted the formation of thylakoid pH gradient, evidenced by a decreased de-epoxidation of the xanthophyll cycle, thus preventing nonphotochemical quenching. Delayed CO2 assimilation due to thylakoid pH gradient restriction was partially reversed by exogenous ATP application. The AOX pathway acts as a photosynthetic electron sink, protecting the photosynthetic apparatus against photoinhibition and accelerating the induction of CO2 assimilation during photosynthetic induction in Rumex K-1 leaves.
Coatis are traditionally divided into two genera (Nasua and Nasuella). Coatis from the lowlands of the Neotropics are larger (Nasua nasua in South America and Nasua narica in Central America) than those from the highlands in the Andean Cordilleras (Nasuella olivacea and maybe Nasuella meridensis). Some authors have claimed that Nasuella should be included in Nasua but strong data have not been provided to support this statement. We reported an extensive mitochondrial (mt) DNA analysis with 205 specimens with complete mitogenomes. Some N. olivacea were intermixed among haplogroups of N. nasua, some haplotypes of N. narica were intermediate between N. nasua and the most recent haplotypes of the Central American N. narica, and N. narica from southern Central America and northern Colombia were introgressed with mtDNA from N. olivacea. Furthermore, the spatial genetic structure of N. nasua, N. narica, and N. olivacea were practically identical. Additionally, we also show, for first the time, the karyotype of N. olivacea. The chromosome morphology of N. olivacea was un-differentiable from that of N. nasua. These data fail to support the independence of these two genera.
Five-sixths nephrectomy is a widely used experimental model of chronic kidney disease (CKD) that is associated with severe mitochondrial dysfunction of the remnant tissue. In this study, we assessed the effect of CKD on mitochondrial respiration separately in the rat kidney cortex and medulla 10 weeks after induction of CKD by subtotal 5/6 nephrectomy (SNX). Mitochondrial oxygen consumption was evaluated on mechanically permeabilized samples of kidney cortex and medulla using high-resolution respirometry and expressed per mg of tissue wet weight or IU citrate synthase (CS) activity. Mitochondrial respiration in the renal cortex of SNX rats was significantly reduced in all measured respiratory states if expressed per unit wet weight and remained lower if recalculated per IU citrate synthase activity, i.e. per mitochondrial mass. In contrast, the profound decrease in the activity of CS in SNX medulla resulted in significantly elevated respiratory states expressing the OXPHOS capacity when Complexes I and II or II only are provided with electrons, LEAK respiration after oligomycin injection, and Complex IV-linked oxygen consumption per unit CS activity suggesting compensatory hypermetabolic state in remaining functional mitochondria that is not sufficient to fully compensate for respiratory deficit expressed per tissue mass. The results document that CKD induced by 5/6 nephrectomy in the rat is likely to cause not only mitochondrial respiratory dysfunction (in the kidney cortex), but also adaptive changes in the medulla that tend to at least partially compensate for mitochondria loss.
Rhipicephalus camicasi Morel, Mouchet et Rodhain, 1976 is thought to be distributed across Africa, Arabian Peninsula and the Mediterranean region. It belongs to the Rhipicephalus sanguineus (Latreille, 1806) species complex. Mitochondrial genome sequences are becoming frequently used for the identification and differentiation of tick species. In the present study, the entire mitochondrial genome of R. cf. camicasi (~15 kb) collected from a camel in Saudi Arabia was sequenced and compared with mitogenomes of two species of Rhipicephalus Koch, 1844. The mitochondrial genome is 87.8% and 91.7% identical to the reference genome of R. sanguineus (sensu stricto, former "temperate lineage") and Rhipicephalus linnaei (Audouin, 1826) (former "tropical lineage"). The current study delivers a molecular reference for material that resembles R. camicasi. We propose to consider the current material, including the complete mitogenome, as the reference for R. camicasi, until a revision using topotypical material is available.
The objective of the present study was to evaluate platelet mitochondrial oxygen consumption using high-resolution respirometry (HRR) and metabolic flux analysis (MFA) and to verify the effect of advanced age on these parameters. HRR was used to analyze permeabilized and intact platelets, MFA to measure oxygen consumption rates (OCR), extracellular acidification rates (ECAR) and ATP production rate in intact fixed platelets. Two groups of healthy volunteers were included in the study: YOUNG (20-42 years, n=44) and older adults (OLD; 70-89 years; n=15). Compared to YOUNG donors, platelets from group OLD participants displayed significantly lower values of oxygen consumption in the Complex II-linked phosphorylating and uncoupled states and the Complex IV activity in HRR protocols for permeabilized cells and significantly lower resting and uncoupled respirations in intact cells when analyzed by both methods. In addition, mitochondrial ATP production rate was also significantly lower in platelets isolated from older adults. Variables measured by both methods from the same bloods correlated significantly, nevertheless those acquired by MFA were higher than those measured using HRR. In conclusion, the study verifies compromised mitochondrial respiration and oxidative ATP production in the platelets of aged persons and documents good compatibility of the two most widely used methods for determining the global performance of the electron-transporting system, i.e. HRR and MFA
Exercise training (ET) is well established to induce vascular adaptations on the metabolically active muscles. These adaptations include increased function of vascular potassium channels and enhanced endothelium-dependent relaxations. However, the available data on the effect of ET on vasculatures that normally constrict during exercise, such as mesenteric arteries (MA), are scarce and not conclusive. Therefore, this study hypothesized that 10 weeks of moderate-intensity ET would result in adaptations towards more vasoconstriction or/and less vasodilatation of MA. Young Fischer 344 rats were randomly assigned to a sedentary group (SED; n=24) or exercise training group (EXE; n=28). The EXE rats underwent a progressive treadmill ET program for 10 weeks. Isometric tensions of small (SED; 252.9±29.5 µm, EXE; 248.6±34.4 µm) and large (SED; 397.7±85.3 µm, EXE; 414.0±86.95 µm) MA were recorded in response to cumulative phenylephrine concentrations (PE; 0-30 µM) in the presence and absence of the BKCa channel blocker, Iberiotoxin (100 nM). In another set of experiments, tensions in response to cumulative concentration-response curves of acetylcholine (ACh) or sodium nitroprusside (SNP) were obtained, and pEC50s were compared. Immunoblotting was performed to measure protein expression levels of the BKCa channel subunits and eNOS. ET did not alter the basal tension of small and large MA but significantly increased their responses to PE, and reduced the effect of BKCa channels in opposing the contractile responses to PE without changes in the protein expression level of BKCa subunits. ET also elicited a sizedependent functional adaptations that involved reduced endothelium-independent and endothelium-dependent relaxations. In large MA the sensitivity to SNP was decreased more than in small MA suggesting impaired nitric oxide (NO)-dependent mechanisms within the vascular smooth muscle cells of ET group. Whereas the shift in pEC50 of ACh-induced relaxation of small MA would suggest more effect on the production of NO within the endothelium, which is not changed in large MA of ET group. However, the eNOS protein expression level was not significantly changed between the ET and SED groups. In conclusion, our results indicate an increase in contraction and reduced relaxation of MA after 10 weeks of ET, an adaptation that may help shunt blood flow to metabolically active tissues during acute exercise.
Autologous and allogenic human pericardia used as biomaterials for cardiovascular surgery are traditionally crosslinked with glutaraldehyde. In this work, we have evaluated the resistivity to collagenase digestion and the cytotoxicity of human pericardium crosslinked with various concentrations of glutaraldehyde in comparison with pericardium crosslinked by genipin, nordihydroguaiaretic acid, tannic acid, and in comparison with unmodified pericardium. Crosslinking retained the wavy-like morphology of native pericardium visualized by second harmonic generation microscopy. The collagenase digestion products were analyzed using SDS-PAGE, capillary electrophoresis, and a hydroxyproline assay. Glutaraldehyde and genipin crosslinking protected the native pericardium efficiently against digestion with collagenase III. Only low protection was provided by the other crosslinking agents. The cytotoxicity of crosslinked pericardium was evaluated using xCELLigence by monitoring the viability of porcine valve interstitial cells cultured in eluates from crosslinked pericardium. The highest cell index, reflecting both the number and the shape of the monitored cells was observed in eluates from genipin. Crosslinking pericardium grafts with genipin therefore seems to be a promising alternative procedure to the traditional crosslinking with glutaraldehyde, because it provides similarly high protection against degradation with collagenase, without cytotoxic effects.
We studied the effects of GABA receptor agonists microinjections
in medullary raphé on the mechanically induced tracheobronchial
cough response in anesthetized, unparalyzed, spontaneously
breathing cats. The results suggest that GABA-ergic inhibition
significantly contributes to the regulation of cough reflex by
action of both GABAA and GABAB receptors. The data are
consistent with inhomogeneous occurrence of GABA-ergic
neurons in medullary raphé and their different involvement in the
cough reflex control. Cells within rostral nucleus raphé obscurus
with dominant role of GABAA receptors and neurons of rostral
nucleus raphé pallidus and caudal nucleus raphé magnus with
dominant role of GABAB receptors participate in regulation of
cough expiratory efforts. These cough control elements are
distinct from cough gating mechanism. GABA-ergic inhibition in
the raphé caudal to obex had insignificant effect on cough.
Contradictory findings for GABA, muscimol and baclofen
administration in medullary raphé suggest involvement of
coordinated activity of GABA on multiple receptors affecting
raphé neurons and/or the local neuronal circuits in the raphé
modulating cough motor drive.
Recenze této knihy by mohla být východiskem k diskusi o dalším směřování české psychodiagnostiky. Jde o základní učebnici psychodiagnostiky a je zřejmě nejčastěji využívána studenty během pregraduálního studia psychologie v rámci předmětu psychodiagnostika dospělých. Lze tedy říci, že má základní význam jako zdroj informací, z něhož čerpají znalosti o psychodiagnostice pozdější profesní psychologové, respektive psychologové se specializací na psychodiagnostiku.