scholarly journals Identification of key residues involved in Si transport by the aquaglyceroporins

2016 ◽  
Vol 148 (3) ◽  
pp. 239-251 ◽  
Author(s):  
Gabriel A. Carpentier ◽  
Alexandre P. Garneau ◽  
Andrée-Anne Marcoux ◽  
Micheline Noël ◽  
Rachelle Frenette-Cotton ◽  
...  

We recently demonstrated that the aquaglyceroporins (AQGPs) could act as potent transporters for orthosilicic acid (H4SiO4). Although interesting, this finding raised the question of whether water and H4SiO4, the transportable form of Si, permeate AQGPs by interacting with the same region of the pore, especially in view of the difference in molecular radius between the two substrates. Here, our goal was to identify residues that endow the AQGPs with the ability to facilitate Si diffusion by examining the transport characteristics of mutants in which residues were interchanged between a water-permeable but Si-impermeable channel (aquaporin 1 [AQP1]) and a Si-permeable but water-impermeable channel (AQP10). Our results indicate that the composition of the arginine filter (XX/R), known to include three residues that play an important role in water transport, may also be involved in Si selectivity. Interchanging the identities of the nonarginine residues within this filter causes Si transport to increase by approximately sevenfold in AQP1 and to decrease by approximately threefold in AQP10, whereas water transport and channel expression remain unaffected. Our results further indicate that two additional residues in the AQP arginine filter may be involved in substrate selectivity: replacing one of the residues has a profound effect on water permeability, and replacing the other has a profound effect on Si permeability. This study has thus led to the identification of residues that could play a key role in Si transport by the AQGPs and shown that substrate selectivity is likely ensured by more than one checkpoint within or near the pore.

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.


Author(s):  
Philip Isett

This chapter presents the equations and calculations for energy approximation. It establishes the estimates (261) and (262) of the Main Lemma (10.1) for continuous solutions; these estimates state that we are able to accurately prescribe the energy that the correction adds to the solution, as well as bound the difference between the time derivatives of these two quantities. The chapter also introduces the proposition for prescribing energy, followed by the relevant computations. Each integral contributing to the other term can be estimated. Another proposition for estimating control over the rate of energy variation is given. Finally, the coarse scale material derivative is considered.


Metahumaniora ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 378
Author(s):  
Vincentia Tri Handayani

AbstrakFolklor yang menghasilkan tradisi lisan merupakan perwujudan budaya yang lahirdari pengalaman kelompok masyarakat. Salah satu bentuk tradisi lisan adalah ungkapan yangmengandung unsur budaya lokal dalam konstruksinya yang tidak dimiliki budaya lainnya.Ungkapan idiomatis memberikan warna pada bahasa melalui penggambaran mental. Dalambahasa Perancis, ungkapan dapat berupa locution dan expression. Perbedaan motif acuansuatu ungkapan dapat terlihat dari pengaruh budaya masyarakat pengguna bahasa. Sebuahleksem tidak selalu didefinisikan melalui unsur minimal, tidak juga melalui kata-kata,baik kata dasar atau kata kompleks, namun dapat melalui kata-kata beku yang maknanyatetap. Hubungan analogis dari makna tambahan yang ada pada suatu leksem muncul dariidentifikasi semem yang sama. Semem tersebut mengarah pada term yang diasosiasikan danyang diperkaya melalui konteks (dalam ungkapan berhubungan dengan konteks budaya).Kata kunci: folklor, ungkapan, struktur, makna idiomatis, kebudayaanAbstractFolklore which produces the oral tradition is a cultural manifestation born out theexperience of community groups. One form of the oral tradition is a phrase that containsthe elements of local culture in its construction that is not owned the other culture. Theidiomatic phrase gives the color to the language through the mental representation. InFrench, the expression can consist of locution and expression. The difference motivesreference of an expression can be seen from the influence of the cultural community thelanguage users. A lexeme is not always defined through a minimal element, nor throughwords, either basic or complex words, but can be through the frost words whose meaningsare fixed. The analogical connection of the additional meanings is on a lexeme arises fromthe identification of the same meaning. The meaning ‘semem’ leads to the associated termsand which are enriched through the context (in idiom related to the cultural context).Keywords : folklore, idioms, structure, idiom meaning, cultureI PENDAHULUAN


Author(s):  
Michel Meyer

Rhetoric has always been torn between the rhetoric of figures and the rhetoric of conflicts or arguments, as if rhetoric were exclusively one or the other. This is a false dilemma. Both types of rhetoric hinge on the same structure. A common formula is provided in Chapter 3 which unifies rhetoric stricto sensu and rhetoric as argumentation as two distinct but related strategies adopted according to the level of problematicity of the questions at stake, thereby giving unity to the field called “Rhetoric.” Highly problematic questions require arguments to justify their answers; non-divisive ones can be treated rhetorically through their answers as if they were self-evident. Another classic problem is how to understand the difference between logic and rhetoric. The difference between the two is due to the presence of questions explicitly answered in the premises in logic and only suggested (or remaining indeterminate) in rhetoric.


Author(s):  
D. T. Gauld ◽  
J. E. G. Raymont

The respiratory rates of three species of planktonic copepods, Acartia clausi, Centropages hamatus and Temora longicornis, were measured at four different temperatures.The relationship between respiratory rate and temperature was found to be similar to that previously found for Calanus, although the slope of the curves differed in the different species.The observations on Centropages at 13 and 170 C. can be divided into two groups and it is suggested that the differences are due to the use of copepods from two different generations.The relationship between the respiratory rates and lengths of Acartia and Centropages agreed very well with that previously found for other species. That for Temora was rather different: the difference is probably due to the distinct difference in the shape of the body of Temora from those of the other species.The application of these measurements to estimates of the food requirements of the copepods is discussed.


2020 ◽  
Vol 15 (S359) ◽  
pp. 188-189
Author(s):  
Daniela Hiromi Okido ◽  
Cristina Furlanetto ◽  
Marina Trevisan ◽  
Mônica Tergolina

AbstractGalaxy groups offer an important perspective on how the large-scale structure of the Universe has formed and evolved, being great laboratories to study the impact of the environment on the evolution of galaxies. We aim to investigate the properties of a galaxy group that is gravitationally lensing HELMS18, a submillimeter galaxy at z = 2.39. We obtained multi-object spectroscopy data using Gemini-GMOS to investigate the stellar kinematics of the central galaxies, determine its members and obtain the mass, radius and the numerical density profile of this group. Our final goal is to build a complete description of this galaxy group. In this work we present an analysis of its two central galaxies: one is an active galaxy with z = 0.59852 ± 0.00007, while the other is a passive galaxy with z = 0.6027 ± 0.0002. Furthermore, the difference between the redshifts obtained using emission and absorption lines indicates an outflow of gas with velocity v = 278.0 ± 34.3 km/s relative to the galaxy.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Haiyan Xu ◽  
Weibing Zhang ◽  
Kai Zhang ◽  
Yue Zhang ◽  
Zhenyu Wang ◽  
...  

Abstract Background Infection with Salmonella enterica usually results in diarrhea, fever, and abdominal cramps, but some people become asymptomatic or chronic carrier as a source of infection for others. This study aimed to analyze the difference in serotype, antimicrobial resistance, and genetic profiles between Salmonella strains isolated from patients and those from asymptomatic people in Nantong city, China. Methods A total of 88 Salmonella strains were collected from patients and asymptomatic people from 2017 to 2018. Serotyping, antimicrobial susceptibility testing, and PFGE analysis were performed to analyze the characteristics of these strains. Results Twenty serotypes belonging to 8 serogroups were identified in the 88 Salmonella strains. S. Typhimurium remained to be the predominant serotype in strains from both patients and asymptomatic people. Among the 27 strains from patients, S. Enteritidis and S. Rissen were shown as the other two major serotypes, while S. London, S. Derby, and S. Meleagridis were demonstrated as the other significant serotypes among the 61 strains from asymptomatic people. Antimicrobial resistance testing revealed that 84.1% of strains from both resources were multi-drug resistant. PFGE displayed a highly discriminative ability to differentiate strains belonging to S. Derby, S. Typhimurium, etc., but could not efficiently differentiate serotypes like S. Enteritidis. Conclusions This study’s results demonstrated that S. Typhimurium could cause human infection in both symptomatic and asymptomatic state; S. London, S. Derby, and S. Meleagridis usually cause asymptomatic infection, while S. Enteritidis infection mainly results in human diseases. The high multi-drug resistance rate detected in the antimicrobial resistance and diverse PFGE profiles of these strains implied that the strains were isolated from different sources, and the increased surveillance of Salmonella from both patients and asymptomatic people should be taken to control the disease.


Science ◽  
2020 ◽  
Vol 371 (6524) ◽  
pp. 72-75 ◽  
Author(s):  
Tyler E. Culp ◽  
Biswajit Khara ◽  
Kaitlyn P. Brickey ◽  
Michael Geitner ◽  
Tawanda J. Zimudzi ◽  
...  

Biological membranes can achieve remarkably high permeabilities, while maintaining ideal selectivities, by relying on well-defined internal nanoscale structures in the form of membrane proteins. Here, we apply such design strategies to desalination membranes. A series of polyamide desalination membranes—which were synthesized in an industrial-scale manufacturing line and varied in processing conditions but retained similar chemical compositions—show increasing water permeability and active layer thickness with constant sodium chloride selectivity. Transmission electron microscopy measurements enabled us to determine nanoscale three-dimensional polyamide density maps and predict water permeability with zero adjustable parameters. Density fluctuations are detrimental to water transport, which makes systematic control over nanoscale polyamide inhomogeneity a key route to maximizing water permeability without sacrificing salt selectivity in desalination membranes.


2020 ◽  
Vol 25 (1) ◽  
Author(s):  
Ye Sun ◽  
Hua Fan ◽  
Xiao-Xia Song ◽  
Hua Zhang

Abstract Background The present study aimed to compare three fixation methods for orotracheal intubation. Methods Through literature retrieval, the effects of the adhesive/twill tape method, fixator method, and adhesive/twill tape–fixator alternation method on patients with tracheal intubation in the intensive care unit (ICU) were compared. Results The fixator and alternation methods were more effective in protecting the tongue mucosa and teeth. The alternation method was superior to the other two methods in maintaining the position of the endotracheal intubation. However, the difference in facial and lip injuries between the three methods was not statistically significant. Conclusion The fixator method can significantly reduce intraoral injury and is more suitable for older people with weak tongue mucosa and loose teeth. These are worth popularizing among a wider group.


2018 ◽  
Vol 6 (4) ◽  
pp. 401-428
Author(s):  
Miriam R. Lowi

Studies of identity and belonging in Gulf monarchies tend to privilege tribal or religious affiliation, if not the protective role of the ruler as paterfamilias. I focus instead on the ubiquitous foreigner and explore ways in which s/he contributes to the definition of national community in contemporary gcc states. Building upon and moving beyond the scholarly literature on imported labor in the Gulf, I suggest that the different ‘categories’ of foreigners impact identity and the consolidation of a community of privilege, in keeping with the national project of ruling families. Furthermore, I argue that the ‘European,’ the non-gcc Arab, and the predominantly Asian (and increasingly African) laborer play similar, but also distinct roles in the delineation of national community: while they are differentially incorporated in ways that protect the ‘nation’ and appease the citizen-subject, varying degrees of marginality reflect Gulf society’s perceptions or aspirations of the difference between itself and ‘the other(s).’


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