Effect of potassium supply on content of apple leaf phosphorus

Well-balanced mineral nutrition of apple trees is critical for fruit quality and storability. The seasonal changes of phosphorus and potassium leaf content were studied in the pot sand culture during the seasons of 2019 and 2020. The treatments comprised the application of the nutrient solution with different concentrations (0.00; 0.68; 1.36; 1.70; 2.04; 2.72; 3.40 g l-1). Leaves were analyzed on potassium and phosphorus content. The increase in potassium supply led to a striking increase in the content of apple leaf phosphorus above the optimal level. An approach to non-invasive detection of the impact of the nutrient imbalance based on hyperspectral reflectance imaging has been proposed.

Controlled ultrafast ππ*-πσ* dynamics in tryptophan-based peptides with tailored micro-environment

Ultrafast charge, energy and structural dynamics in molecules are driven by the topology of the multidimensional potential energy surfaces that determines the coordinated electronic and nuclear motion. These processes are also strongly influenced by the interaction with the molecular environment, making very challenging a general understanding of these dynamics on a microscopic level. Here we use electrospray and mass spectrometry technologies to produce isolated molecular ions with a controlled micro-environment. We measure ultrafast photo-induced ππ*-πσ* dynamics in tryptophan species in the presence of a single, charged adduct. A striking increase of the timescale by more than one order of magnitude is observed when changing the added adduct atom. A model is proposed to rationalize the results, based on the localized and delocalized effects of the adduct on the electronic structure of the molecule. These results offer perspectives to control ultrafast molecular processes by designing the micro-environment on the Angström length scale.

Mutational hotspot in the SARS-CoV-2 Spike protein N-terminal domain conferring immune escape potential

ABSTRACTGlobal efforts are being taken to monitor the evolution of SARS-CoV-2, aiming at early identification of mutations with the potential of increasing viral infectivity or virulence. We report a striking increase in the frequency of recruitment of diverse substitutions at a critical residue (W152), positioned in the N-terminal domain (NTD) of the Spike protein, observed repeatedly across independent phylogenetic and geographical contexts. We investigate the impact these mutations might have on the evasion of neutralizing antibodies. Finally, we uncover that NTD is a region exhibiting particularly high frequency of mutation recruitments, suggesting an evolutionary path on which the virus maintains optimal efficiency of ACE2 binding combined with the flexibility facilitating the immune escape.

Reprogramming: Emerging Strategies to Rejuvenate Aging Cells and Tissues

Aging is associated with a progressive and functional decline of all tissues and a striking increase in many “age-related diseases”. Although aging has long been considered an inevitable process, strategies to delay and potentially even reverse the aging process have recently been developed. Here, we review emerging rejuvenation strategies that are based on reprogramming toward pluripotency. Some of these approaches may eventually lead to medical applications to improve healthspan and longevity.

The SARS-CoV-2 Y453F mink variant displays a striking increase in ACE-2 affinity but does not challenge antibody neutralization

SARS-CoV-2 transmission from humans to animals has been reported for many domesticated species, including cats, dogs and minks. Identification of novel spike gene mutations appearing in minks has raised major concerns about potential immune evasion and challenges for the global vaccine strategy. The genetic variant, known as “cluster-five”, arose among farmed minks in Denmark and resulted in a complete shutdown of the world’s largest mink production. However, the functional properties of this new variant are not established. Here we present functional data on the Y453F cluster-five receptor-binding domain (RBD) and show that it does not decrease established humoral immunity or affect the neutralizing response in a vaccine model based on wild-type RBD or spike. However, it binds the human ACE-2 receptor with a four-fold higher affinity suggesting an enhanced transmission capacity and a possible challenge for viral control.

SNAI2-mediated direct repression of BIM protects rhabdomyosarcoma from ionizing radiation

Ionizing radiation (IR) and chemotherapy are the mainstays of treatment for patients with rhabdomyosarcoma (RMS). Yet, the molecular mechanisms that underlie the success or failure of radiotherapy remain unclear. The transcriptional repressor SNAI2 was previously identified as a key regulator of IR sensitivity in normal and malignant stem cells through its repression of the proapoptotic BH3-only gene PUMA. Here, we demonstrate a clear correlation between SNAI2 expression levels and radiosensitivity across multiple RMS cell lines. Moreover, modulating SNAI2 levels in RMS cells through its overexpression or knockdown can alter radiosensitivity in vitro and in vivo. SNAI2 expression reliably promotes overall cell growth and inhibits mitochondrial apoptosis following exposure to IR, with either variable or minimal effects on differentiation and senescence, respectively. Importantly, SNAI2 knockdown results in a striking increase in expression of the proapoptotic BH3-only gene BIM, and ChIP-seq experiments establish that SNAI2 is a direct repressor of BIM. Since the P53 pathway is nonfunctional in the RMS cells used in this study, we have identified a new, P53-independent SNAI2/BIM axis that could potentially predict clinical responses to IR treatment and be exploited to improve RMS therapy.HighlightsSNAI2 expression levels are directly correlated with protection from radiation in rhabdomyosarcoma.Loss of SNAI2 primes rhabdomyosarcomas for IR-induced apoptosis.SNAI2 directly represses the expression of the proapoptotic BH3-only gene BIM.

Fostering Global Citizenship Through Student Mobility

Although the phenomenon of student mobility can be traced back to over a thousand years, a remarkable increase began from 1995 when the World Trade Organization released the General Agreement on Trade in Services, making higher education a tradable commodity. International mobility programs have the potential to provide the environment for global citizenship by empowering students to be resilient and become citizens of the world. Higher education institutions are clamoring to prepare students for living in highly diverse societies, and countries use the soft power of international exchanges to develop goodwill. However, the striking increase in student mobility has suddenly come to a dramatic halt in recent months globally due to the covid-19 pandemic, and the impact on international students has been most severe. In this context, this paper briefly discusses the evolution of student mobility and how it fosters global citizenship.

Sexual violence in the border zone: the EU, the Women, Peace and Security agenda and carceral humanitarianism in Libya

The last decades have seen a striking increase in international policy seeking to protect against conflict-related sexual violence. Norms of protection are, however, unevenly applied in practice. In this article, I address one such situation: the significant and growing evidence of widespread sexual violence at detention sites in Libya where migrants are imprisoned after interception on the Mediterranean Sea. Drawing on policy documents, human rights reports, interviews with advocates and officials, and an analysis of debates in the EU Parliament and UNHCR's humanitarian evacuation scheme in Libya, I examine how abuses have been framed, and with what effects. I argue that decisions about protection are shaped not only by raced and gendered categorizations but also by a demarcation of bodies in the border zone, where vulnerability is to some degree acknowledged, but agency and responsibility also disavowed by politicians, diplomats and practitioners. The wrong of sexual violence is thus both explicitly recognized but also re-articulated in ways that lessen the obligations of the same states and regional organizations that otherwise champion the Women, Peace and Security (WPS) agenda. The combination of mass pullback and detention for many migrants with evacuation for a vulnerable few is an example of carceral humanitarianism, where ‘rescue’ often translates into confinement and abuse for unwelcome populations. My analysis highlights the importance of the positionality of migrants in the Libyan border zone for the form of recognition they are afforded, and the significant limits to the implementation of the EU's gender-responsive humanitarian policies in practice.

Intrinsic neuronal activity during migration controls the recruitment of specific interneuron subtypes in the postnatal mouse olfactory bulb

Neuronal activity has been identified as a key regulator of neuronal network development, but the impact of activity on migration and terminal positioning of interneuron subtypes is poorly understood. The absence of early subpopulation markers and the presence of intermingled migratory and post-migratory neurons makes the developing cerebral cortex a difficult model to answer these questions. Postnatal neurogenesis in the subventricular zone offers a more accessible and compartmentalized model. Neural stem cells regionalized along the border of the lateral ventricle produce two main subtypes of neural progenitors, granule cells and periglomerular neurons that migrate tangentially in the rostral migratory stream before migrating radially in the OB layers. Here we take advantage of targeted postnatal electroporation to compare the migration of these two population. We do not observe any obvious differences regarding the mode of tangential or radial migration between these two subtypes. However, we find a very striking increase of intrinsic calcium activity only in granule cell precursors when they switch from tangential to radial migration. By decreasing neuronal excitability in granule cell precursors, we find that neuronal activity is critical for normal migratory speed at the end of tangential migration. Importantly, we also find that activity is required for normal positioning and survival of granule cell precursors in the OB layers. Strikingly, decreasing activity of periglomerular neuron precursors did not impact their positioning or survival. Altogether these findings suggest that neuronal excitability plays a subtype specific role during the late stage of migration of postnatally born olfactory bulb interneurons.Significance StatementWhile neuronal activity is a critical factor regulating different aspects of neurogenesis, it has been challenging to study its role during the migration of different neuronal subpopulations. Here, we use postnatal targeted electroporation to label and manipulate the two main olfactory bulb interneuron subpopulations during their migration: granule cell and periglomerular neuron precursors. We find a very striking increase of calcium activity only in granule cell precursors when they switch from tangential to radial migration. Interestingly, blocking activity in granule cell precursors affected their migration, positioning and survival while periglomerular neuron precursors are not affected. These results suggest that neuronal activity is required specifically for the recruitment of granule cell precursors in the olfactory bulb layers.