Organogenesis from shoot segments and via callus of endangered <Emphasis Type="Italic">Kosteletzkya pentacarpos</Emphasis> (L.) Ledeb.

Efficient plant regeneration systems both from shoot segments and via callus organogenesis were developed for Kosteletzkya pentacarpos (L.) Ledeb., a rare and endangered Eurasian species. In the experiments with existing meristems, factors affecting shoot proliferation, including explant type, i.e. decapitated and intact shoots, and plant growth regulators, indole-3-acetic acid or kinetin, were investigated. Shoot proliferation was significantly affected by the type of explant, the hormones and their interaction. The highest shoot multiplication rate was obtained from decapitated shoots. Increasing kinetin concentration promoted shoot elongation regardless of explant type. In intact shoots, shoot length was also affected by increasing auxin concentration, although this effect tends to decrease with higher concentration. Decapitated shoots were not responsive to the addition of auxin. Micropropagation through organogenesis from callus was also investigated. Calli were obtained from leaf, stem internode and root explants. Only the leaf-derived calli produced shoots and indole-3-acetic acid favoured increased numbers of shoots. A number of experiments were conducted for rooting of in vitro produced shoots. All of them induced high rooting frequency, the number and the length of roots being dependent on the strength of the basal medium. The use of 1–2 mg l⁻¹ indole-3-butyric acid resulted in refining the optimal concentration for root elongation. The regenerated plants (70%) survived and flowered in their first vegetative period.     

PED/PEA-15 interacts with the 67 kD laminin receptor and regulates cell adhesion, migration, proliferation and apoptosis

Phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes-15 kD (PED/PEA-15) is an anti-apoptotic protein whose expression is increased in several human cancers. In addition to apoptosis, PED/PEA-15 is involved in the regulation of other major cellular functions, including cell adhesion, migration, proliferation and glucose metabolism. To further understand the functions of this protein, we performed a yeast two-hybrid screening using PED/PEA-15 as a bait and identified the 67 kD high-affinity laminin receptor (67LR) as an interacting partner. 67 kD laminin receptor is a non-integrin cell-surface receptor for the extracellular matrix (ECM), derived from the dimerization of a 37 kD cytosolic precursor (37LRP). The 67LR is highly expressed in human cancers and widely recognized as a molecular marker of metastatic aggressiveness. The molecular interaction of PED/PEA-15 with 67LR was confirmed by pull-down experiments with recombinant His-tagged 37LRP on lysates of PED/PEA-15 transfected HEK-293 cells. Further, overexpressed or endogenous PED/PEA-15 was co-immunoprecipitated with 67LR in PED/PEA-15-transfected HEK-293 cells and in U-373 glioblastoma cells, respectively. PED/PEA-15 overexpression significantly increased 67LR-mediated HEK-293 cell adhesion and migration to laminin that, in turn, determined PED/PEA-15 phosphorylation both in Ser-104 and Ser-116, thus enabling cell proliferation and resistance to apoptosis. PED/PEA-15 ability to induce cell responses to ECM-derived signals through interaction with 67LR may be of crucial importance for tumour cell survival in a poor microenvironment, thus favouring the metastatic spread and colonization.     

Sound-driven synaptic inhibition in primary visual cortex

Multimodal objects and events activate many sensory cortical areas simultaneously. This is possibly reflected in reciprocal modulations of neuronal activity, even at the level of primary cortical areas. However, the synaptic character of these interareal interactions, and their impact on synaptic and behavioral sensory responses are unclear. Here, we found that activation of auditory cortex by a noise burst drove local GABAergic inhibition on supragranular pyramids of the mouse primary visual cortex, via cortico-cortical connections. This inhibition was generated by sound-driven excitation of a limited number of cells in infragranular visual cortical neurons. Consequently, visually driven synaptic and spike responses were reduced upon bimodal stimulation. Also, acoustic stimulation suppressed conditioned behavioral responses to a dim flash, an effect that was prevented by acute blockade of GABAergic transmission in visual cortex. Thus, auditory cortex activation by salient stimuli degrades potentially distracting sensory processing in visual cortex by recruiting local, translaminar, inhibitory circuits.     

Ischemic preconditioning: from the first to the second window of protection.

In many species one or more brief coronary occlusions limit the injuries which a subsequent ischemia-reperfusion can produce in the myocardium. A similar protection has been observed in the majority of organ systems. A first period or window of protection can lasts up to 3 hours and is followed by a second window of protection (SWOP) which begins about 24 hours after the brief coronary occlusions and lasts about 72 hours. Increase of the release of endogenous agents such as adenosine and nitric oxide (NO) may be responsible for both windows through the activation of a protein-kinase C (PKC) which in turn activates ATP sensitive potassium (K+(ATP)) channels. Nitric oxide is also reported to act directly on K+(ATP) channels. Recently, it has been suggested that the channels involved in the protection are mitochondrial rather than sarcolemmal. In SWOP the origin of NO is attributed to the activity of an inducible NO-synthase. Free oxygen radicals released during preconditioning are likely to take part in the delayed protection through the production of peroxynitrite which activates PKC and through the increase of the activity of antioxidant enzymes such as Mn superoxide-dismutase. The production of heat shock proteins is considered a marker rather than a mechanism of SWOP.     

How multiple farming conditions correlate with the composition of the raw cow's milk lactic microbiome

Questionnaires on farming conditions were retrieved from 2129 dairy farms and clustered, resulting in 106 representative raw cow's milk samples analysed in winter and summer. Substantiating the efficiency of our survey, some farming conditions affected the milk physicochemical composition. Culturing identified several species of lactic acid bacteria (LAB) per milk, whose number increased through 16S ribosomal RNA (rRNA) gene sequencing and shotgun metagenome analyses. Season, indoor versus outdoor housing, cow numbers, milk substitutes, ratio cattle/rest area, house care system during lactation, and urea and medium-chain fatty acids correlated with the overall microbiome composition and the LAB diversity within it. Shotgun metagenome detected variations in gene numbers and uniqueness per milk. LAB functional pathways differed among milk samples. Focusing on amino acid metabolisms and matching the retrieved annotated genes versus non-starter lactic acid bacteria (NSLAB) references from KEGG and corresponding to those identified, all samples had the same gene spectrum for each pathway. Conversely, gene redundancy varied among samples and agreed with NSLAB diversity. Milk samples with higher numbers of NSLAB species harboured higher number of copies per pathway, which would enable steady-state towards perturbations. Some farming conditions, which affected the microbiome richness, also correlated with the NSLAB composition and functionality.     

Laminin inhibits the adhesion of a murine tumor of macrophage origin

The adhesive behavior of the M5076 reticulum cell sarcoma, a highly metastatic murine tumor of macrophage origin, was investigated in vitro both in the presence and in the absence of purified exogeneous laminin. Although laminin enhanced the adhesion of other murine cell lines to collagen-coated and plastic surfaces, it reduced the attachment to both substrates of M5076 cells, peritoneal macrophages and the macrophage cell line WEHI-3. Thus, the inhibition appeared to be related to the macrophage nature of the M5076 tumor. The effects of laminin were reversible and did not cause loss of viability or functional capacity of the M5076 cells. Laminin appeared to exert this inhibitory effect by binding to the substrates rather than binding to the cells. These studies indicate that laminin, a glycoprotein from the basement membrane, may either stimulate or inhibit cell attachment, depending on the type of cell.     

Virological and immunological features of SARS-CoV-2-infected children who develop neutralizing antibodies

1. Download : Download high-res image (189KB)
2. Download : Download full-size image