Selection of antibody single-chain variable fragments with improved carbohydrate binding by phage display.

A single-chain variable fragment (Fv) version of a murine monoclonal antibody, Se155-4, specific for Salmonella serogroup B O-polysaccharide, was used as a model system for testing monovalent phage display as a route for enhancing the relatively low affinities that typify anti-carbohydrate antibodies. Random single-chain Fv mutant libraries generated by chemical and error-prone polymerase chain reaction methods were panned against the serogroup B lipopolysaccharide. Panning of a randomly mutated heavy chain variable domain library indicated selection for improved serogroup B binders and yielded six mutants, five of which showed wild type activity by enzyme immunoassay. Two of these were apparently selected on the basis of better functional single-chain Fv yield in Escherichia coli. A heavy chain mutation (Ile77-->Thr) in one mutant, 3B1, appeared to have a particularly dramatic effect, resulting in yields of approximately 120 mg/liter of functional periplasmic product. The sixth mutant, 4B2, had complementarity determining region 1 (CDR1) and CDR2 mutations and demonstrated 10-fold improved binding, by enzyme immunoassay, relative to the wild type. Extensive analysis of antigen-antibody interactions indicated that the improved binding properties of 4B2 were attributable to a higher association rate constant and interaction with an epitope that is larger than the trisaccharide recognized by the wild type. None of the mutations involved known trisaccharide contact residues; this was consistent with analysis of wild type and mutant single-chain Fvs by titration microcalorimetry. Examination of the structure indicated that two mutations in the heavy chain CDR2 provided improved surface complementarity between the protein and the extended epitope encompassing 2 additional hexose residues. However, introduction of only the CDR2 mutations into the wild type structure failed to confer the improved binding properties of 4B2, indicating an indirect effect by the more distant mutations. Panning of randomly mutated light chain variable domain and full-length single-chain Fv mutant libraries did not yield mutants with improved assembly or binding properties

Creencias de los Hombres y Mujeres Americanos sobre la Discriminación de Género: Para los Hombres, Esto No Es Precisamente un Juego de Suma Zero

We surveyed Americans regarding their beliefs about gender discrimination over the past several decades. Men and women agreed that women faced much more discrimination than men in the past, and they agreed that the discrimination gap between men and women has narrowed in recent years. However, men perceived the gap as narrower than women did at all time periods, and reported that there is little difference today in the amount of gender discrimination women and men face. Political ideology moderated these beliefs such that conservative men were most likely to report that anti-Man bias now equals or exceeds anti-Woman bias. Similar to recent research on beliefs about racism, these findings suggest that groups which differ historically in status and power exhibit perceptual differences regarding the changing nature of discrimination.Hemos realizado encuestas a personas americanas sobre sus creencias respecto a la discriminación de género durante las últimas décadas. Tanto hombres como mujeres estaban de acuerdo en que en el pasado las mujeres han sufrido mucha más discriminación que los hombres, y también en que esta diferencia se ha ido estrechando en los últimos años. Sin embargo, a los hombres esta diferencia siempre les ha parecido más estrecha que a las mujeres durante todos los periodos, y perciben que ahora hay pocas diferencias entre la discriminación que afrontan hombres y mujeres. Las ideologías políticas moderan estas creencias, de manera que los hombres conservadores son más propensos a afirmar que el sesgo anti masculino es igual o mayor al sesgo anti femenino. Al igual que algunas investigaciones recientes sobre las creencias respecto al racismo, nuestros hallazgos sugieren que grupos que difieren históricamente en estatus y poder perciben de forma diferente la naturaleza cambiante de la discriminación

The Gaia alerted fading of the FUor-type star Gaia21elv

FU Orionis objects (FUors) are eruptive young stars, which exhibit outbursts that last from decades to a century. Due to the duration of their outbursts, and to the fact that only about two dozens of such sources are known, information on the end of their outbursts is limited. Here we analyse follow-up photometry and spectroscopy of Gaia21elv, a young stellar object, which had a several decades long outburst. It was reported as a Gaia science alert due to its recent fading by more than a magnitude. To study the fading of the source and look for signatures characteristic of FUors, we have obtained follow-up near infrared (NIR) spectra using Gemini South/IGRINS, and both optical and NIR spectra using VLT/X-SHOOTER. The spectra at both epochs show typical FUor signatures, such as a triangular shaped $H$-band continuum, absorption-line dominated spectrum, and P Cygni profiles. In addition to the typical FUor signatures, [OI], [FeII], and [SII] were detected, suggesting the presence of a jet or disk wind. Fitting the spectral energy distributions with an accretion disc model suggests a decrease of the accretion rate between the brightest and faintest states. The rapid fading of the source in 2021 was most likely dominated by an increase of circumstellar extinction. The spectroscopy presented here confirms that Gaia21elv is a classical FUor, the third such object discovered among the Gaia science alerts.Comment: Accepted to MNRA

Male, National, and Religious Collective Narcissism Predict Sexism

Results of three cross-sectional studies indicate that sexism in Poland is associated with collective narcissism—a belief that one’s own group’s (the in-group’s) exaggerated exceptionality is not sufficiently recognized by others—with reference to three social identities: male, religious, and national. In Study 1 (n = 329), male collective narcissism was associated with sexism. This relationship was sequentially mediated by precarious manhood and traditional gender beliefs. In Study 2 (n = 877), Catholic collective narcissism predicted tolerance of violence against women (among men and women) over and above religious fundamentalism and in contrast to intrinsic religiosity. In Study 3 (n = 1070), national collective narcissism was associated with hostile sexism among men and women and with benevolent sexism more strongly among women than among men. In contrast, national in-group satisfaction—a belief that the nation is of a high value—predicted rejection of benevolent and hostile sexism among women but was positively associated with hostile and benevolent sexism among men. Among men and women collective narcissism was associated with tolerance of domestic violence against women, whereas national in-group satisfaction was associated with rejection of violence against women

Light Plays an Essential Role in Intracellular Distribution of Auxin Efflux Carrier PIN2 in Arabidopsis thaliana

BACKGROUND: Light plays a key role in multiple plant developmental processes. It has been shown that root development is modulated by shoot-localized light signaling and requires shoot-derived transport of the plant hormone, auxin. However, the mechanism by which light regulates root development is not largely understood. In plants, the endogenous auxin, indole-3-acetic acid, is directionally transported by plasma-membrane (PM)-localized auxin influx and efflux carriers in transporting cells. Remarkably, the auxin efflux carrier PIN proteins exhibit asymmetric PM localization, determining the polarity of auxin transport. Similar to PM-resident receptors and transporters in animal and yeast cells, PIN proteins undergo constitutive cycling between the PM and endosomal compartments. Auxin plays multiple roles in PIN protein intracellular trafficking, inhibiting PIN2 endocytosis at some concentrations and promoting PIN2 degradation at others. However, how PIN proteins are turned over in plant cells is yet to be addressed. METHODOLOGY AND PRINCIPLE FINDINGS: Using laser confocal scanning microscopy, and physiological and molecular genetic approaches, here, we show that in dark-grown seedlings, the PM localization of auxin efflux carrier PIN2 was largely reduced, and, in addition, PIN2 signal was detected in vacuolar compartments. This is in contrast to light-grown seedlings where PIN2 was predominantly PM-localized. In light-grown plants after shift to dark or to continuous red or far-red light, PIN2 also accumulated in vacuolar compartments. We show that PIN2 vacuolar targeting was derived from the PM via endocytic trafficking and inhibited by HY5-dependent light signaling. In addition, the ubiquitin 26S proteasome is involved in the process, since its inhibition by mutations in COP9 and a proteasome inhibitor MG132 impaired the process. CONCLUSIONS AND SIGNIFICANCE: Collectively, our data indicate that light plays an essential role in PIN2 intracellular trafficking, promoting PM-localization in the presence of light and, on the other hand, vacuolar targeting for protein degradation in the absence of light. Based on these results, we postulate that light regulation of root development is mediated at least in part by changes in the intracellular distribution of auxin efflux carriers, PIN proteins, in response to the light environment