Efeito da sedação do midazolam, quetamina e butorfanol nos valores do ultrassom com Doppler espectral na artéria femoral e grandes artérias abdominais de gatos

Real time information about direction and type of blood flow can be obtained with Doppler ultrasound. In the literature it was not found data obtained with this method from celiac and cranial mesenteric artery in cats. Moreover, sedation of the animal is occasionally necessary to obtain more information on any blood vessel using this method. The purpose of this study was to evaluate the quantitative aspects of spectral waves formed from blood flow of the celiac, cranial mesenteric, renal, external iliac, femoral, and aortic arteries in healthy cats, and to compare them with the same animals when subjected to midazolam, ketamine, and butorphanol sedation. We also measured the heart rate. Twenty healthy adult cats were evaluated. The values obtained for resistivity index and pulsatility index from the celiac artery were 0.62 ± 0.10 and 1.29 ± 0.55, and those from the mesenteric artery were 0.68 ± 0.09 and 1.37 ± 0.39, respectively. Although heart rate was higher in sedated animals, no significant statistical difference was found in case of other parameters, except celiac artery end diastolic velocity and time averaged mean velocity and iliac artery resistivity and pulsatility index. Thus, we provide the Doppler velocimetry parameter from celiac and mesenteric arteries and conclude that this protocol does not alter the values of Doppler ultrasound in the selected vessels, except the celiac and iliac arteries.Informações em tempo real da direção e tipo de fluxo sanguíneo podem ser obtidas com ultrassonografia com Doppler. Existe na literatura dados relativos a esses parâmetros, em gatos não sedados, obtidos das artérias: aorta, renal, ilíaca e femoral; no entanto não foram encontrados na literatura dados relativos às artérias celíaca e mesentérica cranial. Além disso, ocasionalmente há necessidade de sedar animais inquietos ou agressivos, para que seja possível a realização deste exame. O objetivo do trabalho foi avaliar os aspectos quantitativos da onda espectral formada pelo fluxo sanguíneo das artérias: celíaca, mesentérica cranial, renal, ilíaca externa, femoral e aorta abdominal de gatos hígidos e compará-los aos obtidos dos mesmos animais submetidos à sedação com midazolam, cetamina e butorfanol. A frequência cardíaca também foi mensurada. Foram avaliados 20 gatos SRD adultos e saudáveis. Os valores encontrados em animais não sedados na artéria celíaca de índice de resistividade foi 0,62 ± 0,10 e índice de pulsatilidade 1,29 ± 0,55, enquanto da artéria mesentérica cranial, 0,68 ± 0,11 e 1,37 ± 0,39, respectivamente. Apesar da frequência cardíaca mais elevada nos animais sedados, não foram encontradas diferenças estatisticamente significativas dentre os demais parâmetros avaliados, exceto na velocidade diastólica final e velocidade média da artéria celíaca, e índice de resistividade e de pulsatilidade da artéria ilíaca. Dessa forma, foram fornecidos parâmetros dopplervelocimétricos da artéria celíaca e mesentérica cranial e conclui-se que o protocolo utilizado não alterou os valores encontrados por ultrassonografia Doppler nos vasos selecionados, exceto da artéria celíaca e da ilíaca

Minimum O2 levels during storage to inhibit aerobic respiration and prolong the postharvest life of Tommy Atkins mangoes produced in different growing seasons.

The definition of the minimum O2 levels required to maximally inhibit fruit aerobic respiration is essential to efficiently delay ripening and senescence during long-distance transportation. The aim of this study was to determine the minimum O2 levels required to maximally inhibit the aerobic respiration and prolong the post- harvest life of ?Tommy Atkins? mangoes produced during the summer, winter and spring growing seasons in the S ?ao Francisco Valley (SFV), Brazil. For the identification of the minimum O2 levels, mangoes were stored for 42 days at 9 ?C and 90?95% RH. The change from aerobic to anaerobic metabolism was weekly determined based on the levels of O2, CO2 and ethanol production inside hermetically closed containers containing fruit samples. The minimum O2 levels required to maintain aerobic respiration of mangoes produced in the summer, winter and spring changed from 0.25 to 13.75 kPa, 0.80 to 2.30 kPa and 1.42 to 17.40 kPa, respectively, as the storage duration increased. In order to validate the minimum O2 levels to maintain fruit aerobic respiration and quality, ?Tommy Atkins? mangoes produced in the SFV were harvested at the commercial maturity in the winter growing season in 2022 and were stored under dynamic controlled atmosphere (DCA) conditions with the minimum O2 levels determined with fruit produced in the same growing season in the previous year, 2021. Fruit stored under DCA were compared to fruit stored in refrigerated atmosphere (RA) for 60 days at 9 ?C and 90?95% RH. The minimum O2 levels used in the DCA effectively inhibited fruit ripening, controlled black flesh and reduced rot incidence during 60 days of cold storage and 60 + 7 days of shelf life

Co-Conserved Features Associated with cis Regulation of ErbB Tyrosine Kinases

BACKGROUND: The epidermal growth factor receptor kinases, or ErbB kinases, belong to a large sub-group of receptor tyrosine kinases (RTKs), which share a conserved catalytic core. The catalytic core of ErbB kinases have functionally diverged from other RTKs in that they are activated by a unique allosteric mechanism that involves specific interactions between the kinase core and the flanking Juxtamembrane (JM) and COOH-terminal tail (C-terminal tail). Although extensive studies on ErbB and related tyrosine kinases have provided important insights into the structural basis for ErbB kinase functional divergence, the sequence features that contribute to the unique regulation of ErbB kinases have not been systematically explored. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we use a Bayesian approach to identify the selective sequence constraints that most distinguish ErbB kinases from other receptor tyrosine kinases. We find that strong ErbB kinase-specific constraints are imposed on residues that tether the JM and C-terminal tail to key functional regions of the kinase core. A conserved RIxKExE motif in the JM-kinase linker region and a glutamine in the inter-lobe linker are identified as two of the most distinguishing features of the ErbB family. While the RIxKExE motif tethers the C-terminal tail to the N-lobe of the kinase domain, the glutamine tethers the C-terminal tail to hinge regions critical for inter-lobe movement. Comparison of the active and inactive crystal structures of ErbB kinases indicates that the identified residues are conformationally malleable and can potentially contribute to the cis regulation of the kinase core by the JM and C-terminal tail. ErbB3, and EGFR orthologs in sponges and parasitic worms, diverge from some of the canonical ErbB features, providing insights into sub-family and lineage-specific functional specialization. CONCLUSION/SIGNIFICANCE: Our analysis pinpoints key residues for mutational analysis, and provides new clues to cancer mutations that alter the canonical modes of ErbB kinase regulation

Sedation Effect of Acepromazine and Butorphanol in Dopplervelocimetric Parameters in Great Abdominal Arteries and Femoral Artery in Dogs

Background: Doppler ultrasound is a non-invasive diagnostic imaging technique that allows vascular anatomical and dynamics evaluation. Each artery has flow velocity profiles and different Doppler spectrum. The purpose of this study was to determine if sedation with acepromazine and butorphanol in dogs alters Doppler velocimetric values and diameter from abdominal aorta, celiac, mesenteric cranial, renal, external iliac and femoral arteries of healthy dogs.Materials, Methods & Results: Twenty healthy female dogs, aged 1 to 5 years, with body weight ranging from 10 to 25 kg, were evaluated with Doppler ultrasound in order to obtain: peak systolic velocity, end diastolic velocity, time average medium velocity, time average maximum velocity, resistive index, pulsatility index, and diameter from abdominal aorta, celiac, mesenteric cranial, renal, external iliac and femoral arteries. The same animals were sedated with acepromazine (0.02 mg/kg) and buthorphanol (0.4 mg/kg) and the same parameters were reevaluated. The heart rate was also measured. The study was approved by the Animal Ethics Committee of UFRGS, under the 25552 protocol, and the owners signed an informed consent form. Statistical analysis was performed with pared t test.The heart rate was statistically significant different, 98 ± 20.13 bpm before and 79 ± 17.74 after sedation. The exam was done before and after sedation in all selected vessels, except the celiac and cranial mesenteric artery, which were possible only in 35% and 45% respectively. All measured arteries exhibit difference in at least two of the analyzed parameters, except femoral artery, that only diameter was different.Discussion: Each vessel was selected because of its importance, and each of them has its own characteristic waveform. Changes in patterns of flow velocity of the celiac artery and mesenteric can help to determine the physiological condition of the gastrointestinal tract; in the case of renal arteries are associated with diseases involving parenchyma and; thrombosis in the aorta and the iliac and femoral arteries may be difficult to evaluate without the Doppler image. Examination of the AC and AMC before and after sedation not could be performed in all animals, maybe because the present work was carried out with only fasting requirement, without using dimethicone, and one of the difficulties encountered was the presence of gas in the gastrointestinal tract. Another factor that may have contributed to these findings is that the acute stress of containment and other environmental factors can cause release of vasopressin and leads to vasoconstriction of the splanchnic vascular bed. The dopplervelocimetric data found in celiac, mesenteric cranial, renal and femoral arteries in non-sedated animals was similar to what was described by other authors. Although all dogs demonstrated relaxation during the exam, this sedation protocol alters the values found with Doppler ultrasound in the selected vessels, except femoral artery, which caused only increase of diameter. The Doppler differences found can be a consequence of a decrease in heart rate associated with longer cycle length, and therefore, larger diastolic volume with vessels that stayed with same diameter, or in case of caudal abdominal aorta, that reduced the diameter. This study compared the dopplervelocimetric values to the ones described by other authors in non-sedated animals and demonstrated that although acepromazine and buthorphanol are a good option to sedate dogs to perform ultrasound exam, they alter the Doppler values from aorta abdominal, celiac, cranial mesenteric, renal, external iliac arteries and the femoral artery diameter

Reversible association of ribulose-1, 5-bisphosphate carboxylase/oxygenase activase with the thylakoid membrane depends upon the ATP level and pH in rice without heat stress

Ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) activase (RCA) in the thylakoid membrane (TM) has been shown to play a role in protection and regulation of photosynthesis under moderate heat stress. However, the physiological significance of RCA bound to the TM (TM–RCA) without heat stress remains unknown. In this study, it is first shown, using experiments in vivo, that the TM–RCA varies in rice leaves at different development stages, under different environmental conditions, and in a rice mutant. Furthermore, it is shown that the amount of TM–RCA always increased when the Rubisco activation state and the pH gradient across the TM (ΔpH) decreased. It was then demonstrated in vitro that the RCA bound dynamically to TM and the amount of TM–RCA increased during Rubisco activation. A high level of ATP and a high pH value promoted the dissociation of RCA from the TM. Both the RCA association with and dissociation from the TM showed conformational changes related to the ATP level or pH as indicated by the changes in fluorescence intensity of 1-anilinonaphthalene-8-sulphonic acid (ANS) binding to RCA. These results suggest that the reversible association of RCA with the TM is ATP and pH (or ΔpH) dependent; it might be involved in the RCA activation of Rubisco, in addition to the previously discovered role in the protection and regulation of photosynthesis under heat stress

Broad Spectrum Pro-Quorum-Sensing Molecules as Inhibitors of Virulence in Vibrios

Quorum sensing (QS) is a bacterial cell-cell communication process that relies on the production and detection of extracellular signal molecules called autoinducers. QS allows bacteria to perform collective activities. Vibrio cholerae, a pathogen that causes an acute disease, uses QS to repress virulence factor production and biofilm formation. Thus, molecules that activate QS in V. cholerae have the potential to control pathogenicity in this globally important bacterium. Using a whole-cell high-throughput screen, we identified eleven molecules that activate V. cholerae QS: eight molecules are receptor agonists and three molecules are antagonists of LuxO, the central NtrC-type response regulator that controls the global V. cholerae QS cascade. The LuxO inhibitors act by an uncompetitive mechanism by binding to the pre-formed LuxO-ATP complex to inhibit ATP hydrolysis. Genetic analyses suggest that the inhibitors bind in close proximity to the Walker B motif. The inhibitors display broad-spectrum capability in activation of QS in Vibrio species that employ LuxO. To the best of our knowledge, these are the first molecules identified that inhibit the ATPase activity of a NtrC-type response regulator. Our discovery supports the idea that exploiting pro-QS molecules is a promising strategy for the development of novel anti-infectives

Mechanochemical basis of protein degradation by a double-ring AAA+ machine

Molecular machines containing double or single AAA+ rings power energy-dependent protein degradation and other critical cellular processes, including disaggregation and remodeling of macromolecular complexes. How the mechanical activities of double-ring and single-ring AAA+ enzymes differ is unknown. Using single-molecule optical trapping, we determine how the double-ring ​ClpA enzyme from Escherichia coli, in complex with the ​ClpP peptidase, mechanically degrades proteins. We demonstrate that ​ClpA unfolds some protein substrates substantially faster than does the single-ring ​ClpX enzyme, which also degrades substrates in collaboration with ​ClpP. We find that ​ClpA is a slower polypeptide translocase and that it moves in physical steps that are smaller and more regular than steps taken by ​ClpX. These direct measurements of protein unfolding and translocation define the core mechanochemical behavior of a double-ring AAA+ machine and provide insight into the degradation of proteins that unfold via metastable intermediates.Howard Hughes Medical InstituteNational Institutes of Health (U.S.) (Grant AI-16892

The Lesser Known Challenge of Climate Change: Thermal Variance and Sex-Reversal in Vertebrates with Temperature-Dependent Sex Determination

Climate change is expected to disrupt biological systems. Particularly susceptible are species with temperature-dependent sex determination (TSD), as in many reptiles. While the potentially devastating effect of rising mean temperatures on sex ratios in TSD species is appreciated, the consequences of increased thermal variance predicted to accompany climate change remain obscure. Surprisingly, no study has tested if the effect of thermal variance around high-temperatures (which are particularly relevant given climate change predictions) has the same or opposite effects as around lower temperatures. Here we show that sex ratios of the painted turtle (Chrysemys picta) were reversed as fluctuations increased around low and high unisexual mean-temperatures. Unexpectedly, the developmental and sexual responses around female-producing temperatures were decoupled in a more complex manner than around male-producing values. Our novel observations are not fully explained by existing ecological models of development and sex determination, and provide strong evidence that thermal fluctuations are critical for shaping the biological outcomes of climate change