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The effects of leaf expansion on leaf cell physiology and chlorophyll biosynthesis were evaluated in peach tree. The expanding leaves (young leaves) and the expanded leaves (old leaves) of Rich May peach cultivar grafted onto Garnem were compared. The parameters related to leaf expansion were evaluated end of May. Stomatal conductance increased in expanded leaves, while leaf temperature decreased. The difference in stomatal conductance appeared to be associated with stomata size rather than stomata number. The concentrations of chlorophyll precursors including Proto IX, Mg-Proto IX and Pchlide increased during leaf expansion. Cortical cell division and expansion increased during leaf expansion. Furthermore, xylem size and number significantly increased during leaf expansion. Cell expansion had a major influence on leaf size in peach., Şeftali ağacında yaprak büyümesinin yaprak hücre fizyolojisi ve klorofil biyosentezi üzerindeki etkileri değerlendirilmiştir. Garnem üzerine aşılı Rich May şeftali çeşidinin büyümekte olan yaprakları (genç yapraklar) ve büyüyen yaprakları (yaşlı yapraklar) karşılaştırılmıştır. Yaprak büyümesi ile ilgili parametreler Mayıs ayı sonunda değerlendirilmiştir. Büyümüş yapraklarda stoma iletkenliği artarken yaprak sıcaklığı düşmüştür. Stoma iletkenliğindeki farkın stoma sayısından ziyade stoma büyüklüğü ile ilişkili olduğu görülmüştür. Proto IX, Mg-Proto IX ve Pchlide dahil olmak üzere klorofil öncüllerinin konsantrasyonları yaprak büyümesi sırasında artmıştır. Yaprak büyümesi sırasında kortikal hücre bölünmesi ve genişlemesi artmıştır. Ayrıca, yaprak büyümesi sırasında ksilem boyutu ve sayısı önemli ölçüde artmıştır. Şeftalide hücre genişlemesinin yaprak boyutu üzerinde önemli bir etkisi olmuştur.

Lysigenous aerenchyma is a gas space created by cortical cell death that enables efficient oxygen diffusion within plants and reduces the energy costs associated with root cells. Recent studies have demonstrated the benefits of aerenchyma formation under flooding, drought, and nutrient deficiency, although further studies will be necessary to understand the mechanisms involved.

Traumatic brain injury (TBI) is a major cause of mortality and long-term disability around the world. Even mild to moderate TBI can lead to lifelong neurological impairment due to acute and progressive neurodegeneration and neuroinflammation induced by the injury. Thus, the discovery of novel treatments which can be used as early therapeutic interventions following TBI is essential to restrict neuronal cell death and neuroinflammation. We demonstrate that orally administered N-acetyl-l-leucine (NALL) significantly improved motor and cognitive outcomes in the injured mice, led to the attenuation of cell death, and reduced the expression of neuroinflammatory markers after controlled cortical impact (CCI) induced experimental TBI in mice. Our data indicate that partial restoration of autophagy flux mediated by NALL may account for the positive effect of treatment in the injured mouse brain. Taken together, our study indicates that treatment with NALL would be expected to improve neurological function after injury by restricting cortical cell death and neuroinflammation. Therefore, NALL is a promising novel, neuroprotective drug candidate for the treatment of TBI.

Macrofibrils, the main structural features within the cortical cells of mammalian hair shafts, are long composite bundles of keratin intermediate filaments (KIFs) embedded in a matrix of keratin-associated proteins. The KIFs can be helically arranged around the macrofibril central axis, making a cylinder within which KIF helical angle relative to macrofibril axis increases approximately linearly from macrofibril centre to edge. Mesophase-based self-assembly has been implicated in the early formation of macrofibrils, which first appear as liquid-crystal tactoids in the bulb of hair follicles. Formation appears to be driven initially by interactions between pre-keratinized KIFs. Differences in the nature of these KIF-KIF interactions could result in all macrofibrils being internally twisted in a single handedness, or a 50:50 mixture of handedness within each cortical cell. We data-mined 41 electron tomograms containing three-dimensional macrofibril data from previously published studies of hair and wool. In all 644 macrofibrils examined we found that within each tomogram all macrofibrils had the same handedness. We concluded that earlier reports of left- and right-handed macrofibrils were due to artefacts of imaging or data processing. A handedness marker was used to confirm (using re-imaged sections from earlier studies) that, in both human and sheep, all macrofibrils are left-handed around the macrofibril axis. We conclude that this state is universal within mammalian hair. This also supports the conclusion that the origin of macrofibril twist is the expression of chiral twisting forces between adjacent KIFs, rather than mesophase splay and bending forces relaxing to twisting forces acting within a confined space.

Radial expansion is a classic response of roots to mechanical impedance that has generally been assumed to aid penetration. We analysed the response of maize nodal roots to impedance to test the hypothesis that radial expansion is not related to the ability of roots to cross a compacted soil layer. Genotypes varied in their ability to cross the compacted layer, and those with a steeper approach to the compacted layer or less radial expansion in the compacted layer were more likely to cross the layer and achieve greater depth. Root radial expansion was due to cortical cell size expansion, while cortical cell file number remained constant. Genotypes and nodal root classes that exhibited radial expansion upon encountering the compacted soil layer also thickened in response to exogenous ethylene in hydroponic culture, i.e. radial expansion in response to ethylene was correlated with the thickening response to impedance in soil. We propose that ethylene insensitive roots, i.e. those that do not thicken and are able to overcome impedance, have a competitive advantage under mechanically impeded conditions as they can maintain their elongation rates. We suggest that prolonged exposure to ethylene could function as a stop signal for axial root growth.

Tissue optical clearing technique provides a prospective solution for the application of advanced optical methods in life sciences. This chapter firstly gives a brief introduction to mechanisms of tissue optical clearing techniques, from the physical mechanism to chemical mechanism, which is the most important foundation to develop tissue optical clearing methods. During the past years, in vitro and in vivo tissue optical clearing methods were developed. In vitro tissue optical clearing techniques, including the solvent-based clearing methods and the hydrophilic reagents-based clearing methods, combined with labeling technique and advanced microscopy, can be applied to image 3D microstructure of tissue blocks or whole organs such as brain and spinal cord with high resolution. In vivo skin or skull optical clearing, promise various optical imaging techniques to detect cutaneous or cortical cell and vascular structure and function without surgical window.

During brain development, the daughter cells of neural stem cells have to make a choice — either to become new stem cells or to differentiate into neurons. In a recent issue of Science, Iwata et al. (2020) show that these fate decisions can be determined after mitosis by mitochondrial remodeling.

Summary In this issue, Laukoter et al., 2020 report that parent-of-origin-dependent expression is homogeneous across distinct cortical cell types and within individual populations. Conversely, they observe preferential sensitivity of astrocytes to altered doses of imprinted loci.

Reduced cortical cell files (CCFN) and enlarged cortical cells (CCS) reduce root maintenance costs. We used OpenSimRoot, a functional-structural model, to test the hypothesis that larger CCS, reduced CCFN, and their interactions with root cortical aerenchyma (RCA), are useful adaptations to suboptimal soil N, P, and K availability. Interactions of CCS and CCFN with lateral root branching density (LRBD) and increased carbon availability were evaluated under limited N, P and K availability. The combination of larger CCS and reduced CCFN increases the growth of maize up to 105%, 106%, and 144%, respectively, under limited N, P, or K availability. Interactions among larger CCS, reduced CCFN, and greater RCA results in combined growth benefits of up to 135%, 132%, and 161% under limited N, P, and K levels, respectively. Under low phosphorus and potassium availability, increased LRBD approximately doubles the utility of larger CCS and reduced CCFN. The utility of larger CCS and reduced CCFN is reduced by greater C availability as may occur in future climate scenarios. Our results support the hypothesis that larger CCS, reduced CCFN, and their interactions with RCA could increase nutrient acquisition by reducing root respiration and root nutrient demand. Phene synergisms may exist between CCS, CCFN, and LRBD. Natural genetic variation in CCS and CCFN merit consideration for breeding cereal crops with improved nutrient acquisition, which is critical for global food security.One sentence summaryFunctional-structural modeling indicates that enlarged root cortical cells and reduced cortical cell file number decrease root maintenance cost, permitting greater soil exploration, resource capture, and plant growth under suboptimal nitrogen, phosphorus and potassium availability.

The neocortex has an unparalleled diversity of cell types, which are generated during development through a series of temporally orchestrated events that are under tight evolutionary constraint and are critical for proper cortical assembly and function. However, the molecular logic that governs the establishment and organization of cortical cell types remains elusive, largely due to the large number of cell classes undergoing dynamic cell-state transitions over extended developmental timelines. Here, we have generated a comprehensive single-cell RNA-seq and single-cell ATAC-seq atlas of the developing mouse neocortex, sampled every day throughout embryonic corticogenesis. We computationally reconstruct developmental trajectories across the diversity of cortical cell classes, and infer the gene regulatory programs that accompany their lineage bifurcation decisions and their differentiation trajectories. Finally, we demonstrate how this developmental map pinpoints the origin of lineage-specific developmental abnormalities linked to aberrant corticogenesis in mutant animals. The data provides the first global picture of the regulatory mechanisms governing cellular diversification in the neocortex.

During sleep and anesthesia, large groups of neurons throughout the entire cortex activate rhythmically producing wavefronts of activity referred to as slow-wave activity (SWA). In the arousal process, the brain restores its integrative and complex activity. The network mechanisms underlying this global state transition remain however to be elucidated. Here we investigated the network features shaping the SWA under fading anesthesia. Using electrocorticographical recordings of wide cortical areas of the mouse brain, we developed a quantitative measure of the anesthesia level based on slow-wave frequency and complexity. At deep anesthesia, we document a stringent alternation of posterior-anterior-posterior modes of propagation. With fading anesthesia, SWA evolves to produce a plethora of metastable spatiotemporal patterns. A network model of spiking neurons reproduced the data using short-range connectivity, subcortical input and a local activity-dependent adaptation. The emergence from deep anesthesia does not require modifying the connectivity, but small changes in the local excitability of cortical cell assemblies, further supporting the hypothesis of a tight bound between scales in the brain.

The study was carried out to determine effect of brewery effluent on the anatomical and morphological characters of Talinum triangulare. Seeds from matured T. triangulare were germinated and transplanted into plastic containers. The seeds were irrigated with 10, 20, 30 and 40% effluent concentrations respectively. A control experiment irrigated with normal water was also set aside. Data were collected on weekly basis until after the thirteenth week when the experiment was terminated. The plant showed significant reduction in the leaf area, seed number, shoot height, this morphological response is also associated with a reduction in various anatomical structure that were studied. The significant reduction was more obvious on plants irrigated with the 30 and 40% effluent concentrations. Stem tissue such as epidermis, cortical cell distance and vessel diameter showed significant reduction. The reduction in the morphological and anatomical character might be an adaptive mechanisms employed by the plant in order to cope with the heavy concentration of the effluent. This study showed that brewery effluents have toxic effect on the T. triangulare and the effects were more pronounced on those irrigated with 30 and 40% effluent concentrations. The physical and morphological characters observed in plants are the repercussion of the various endogenous characters among which are the anatomical characters. Key words: Brewery effluent, vegetables, irrigation, plant cells.

Evolution of the brain Just how related are reptilian and mammalian brains? Tosches et al. used single-cell transcriptomics to study turtle, lizard, mouse, and human brain samples. They assessed how the mammalian six-layered cortex might be derived from the reptilian three-layered cortex. Despite a lack of correspondence between layers, mammalian astrocytes and adult neural stem cells shared evolutionary origins. General classes of interneuron types were represented across the evolutionary span, although subtypes were species-specific. Pieces of the much-folded mammalian hippocampus were represented as adjacent fields in the reptile brains. Science , this issue p. 881

The null hypothesis of the experiments reported is that the cuticle and cortical morphology of rare animal fibres are similar. The investigation also examined if the productivity and age of alpacas were associated with cuticle morphology and if seasonal nutritional conditions were related to cuticle scale frequency. Cuticle and cortical cell dimensions and ellipticity of the fibre cross section were investigated in 32 samples of cashmere, alpaca, mohair, bison, qiviut and vicuna from various origins. In addition, 24 Peruvian alpaca samples from animals ages 2–6 years and of varying fleece productivity were examined. Cuticle scale frequency, cuticle thickness and cortical cell dimensions (length, diameter, volume and ratio of length to diameter) and ellipticity differed between fibres and cuticle scale frequency also varied with mean fibre diameter. For Peruvian alpaca fleece samples, cuticle scale frequency varied with the age of alpaca and fleece productivity. Fibre ellipticity increased with inc...