The biophysics of plant growth in a reversed electrostatic field: A comparison with conventional electrostatic and electrokinetic field growth responses

The growth of corn and bean plants in a reversed electrostatic field (soil positive) was investigated with reference to previous data for growth in a conventional electrostatic field (soil negative) and an electrokinetic (a.c.) field. Plant and leaf tip damage was observed for high potential gradients in the reversed field. Spectroscopic analyses of the damaged plant sections revealed micro-chemical activity essentially identical to that observed for conventional electrostatic and electrokinetic field growth.While the plant and leaf polarities for all three modes of electrification were found to be essentially consistent,the severity of leaf damage for identical field conditions was less for plants grown in the reversed electrostatic field as compared with conventional field growth. Leakage currents were also higher in the reversed field environments.It appears that plant growth responses are influenced, to a large extent, by the magnitude of active current flow. A summarization of all existing data indicated that plant growth in an electric field, regardless of mode (static or dynamic) is generally retarded at leakage currents in excess of 10^–5 amp, and may be stimulated for currents of 10^–8 amp. Current levels of 10^–16 amp and lower appeared to have no measurable effect on plant physiology.

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Zusammenfassung Das Wachstum von Mais- und Bohnenpflanzen im umgekehrten elektrostatischen Feld wurde mit Bezug auf frühere Ergebnisse über das Wachstum in einem konventionellen elektrostatischen Feld (Boden neg.)und einem elektrokinetischen(~) Feld untersucht. Pflanzen- und Blattspitzenschäden wurden bei hohen Potentialgradienten im umgekehrten Feld beobachtet. Spektroskopische Analysen der geschädigten Pflanzenabschnitte ergaben gleiche mikrochemische Aktivität wie beim Wachstum im konventionellen elektrostatischen und elektrokinetischen Feld.Während die Pflanzen-und Blattpolaritäten für alle 3 Arten der Elektrifizierung gleich beständig gefunden wurden, war das Ausmass des Blattschadens bei identischen Feldbedingungen geringer bei Pflanzen, die im umgekehrten elektrostatischen Feld wuchsen, bezogen auf das Wachstum bei konventionellen Feldbedingungen.Verlustströme waren grösser im umgekehrten Feld. Es scheint, dass Pflanzenwachstumsreaktionen in starkem Masse von der Grösse des aktiven Stromflusses beeinflusst werden. Eine Zusammenfassung aller Ergebnisse zeigt, dass Pflanzenwachstum im elektrischen Feld unabhängig von der Art (statisch oder dynamisch) im allgemeinen verzögert wird bei Verlustströmen über 10^–5 amp und angeregt werden kann durch Ströme von 10^–8 amp. Stromstärken von 10^–16 amp und weniger scheinen keinen messbaren Effekt auf das Pflanzenwachstum zu haben.

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Resume On a examiné les conditions de croissance de plants de pois et de maïs dans un champ électrostatique renversé (sol positif)en les comparant à des valeurs antérieures, acquises dans un champ électrostatique conventionnel (sol négatif) et un champ électro-cinétique (alternatif). On a constaté des dégâts aux plantes et à la pointe des feuilles dans le cas de gradients potentiels élevés par champ renversé. L'analyse spectroscopique des parties endommagées a révélé une activité micro-chimique identique dans son ensemble à celle observée dans le cas de champs électrostatiques conventionnels ou électro-cinétiques. Alors que la polarité des plantes et des feuilles restait constante dans les trois cas, le degré de dommage aux feuilles était, pour des conditions de champ identiques,plus faible chez les plantes soumises à un champ renversé que pour celles qui poussaient dans un champ électrostatique conventionnel. Les fuites de charge furent par contre plus importantes dans un champ renversé. Il semble que les réactions de croissance des plantes sont influencées dans une large mesure par l'intensité du "courant actif".Une récapitulation de tous les résultats obtenus montre que la croissance des plantes dans un champ électrique, quel qu'en soit le genre (statique ou dynamique) est généralement ralentie par des fuites de charge de plus de 10^–5 amp et stimulée par des courants de 10^–8 amp. Des courants de 10^–16 amp et moins ne semblent pas avoir de conséquences mesurables sur la croissance des plantes.

     

Morphological and functional differentiation of cryopreserved lactating bovine mammary cells cultured on floating collagen gels

Cryopreserved bovine mammary epithelial cells prepared from lactating mammary tissue synthesize and secrete the milk proteins alpha_s1-casein, lactoferrin (Lf), and alpha-lactalhumin during in vitro culture on collagen gels in serum-free medium. Each milk protein is differently regulated by detachment and thickness of the collagen substratum, fetal calf scrum, and prolactin in the medium. Collagen detachment did not modulate lactoferrin secretion but strongly induced casein secretion, with detachment on day 6 (after formation of cell sheets) inducing casein secretion to 3 μg/ml medium, which was 2–3-fold higher than for cells on collagen detached on day 2 (prior to cell spreading to form sheets), and ten-fold higher than for cells grown on collagen not detached. Alpha-lactalbumin secretion was also induced, but only to low levels, in cells grown on detached but not on attached collagen. Cells grown on thin collagen gels secreted lower levels of lactoferrin and casein compared to cells on thick collagen. Lactoferrin but not casein secretion was increased in cells grown in the presence of fetal calf serum. Casein but not lactoferrin secretion was completely dependent on prolactin. Cells grown serum-free on collagen gels detached on day 6 of culture showed a polarized epithelial cell layer with high differentiation evidenced by the apical microvilli, tight junctions, and fat droplets surrounded by casein-containing secretory vesicles. An underlying layer of myoepithelial-like cells was also evident. These studies show for eryopreserved primary bovine mammary cells prepared from lactating mammary tissue the induction of highly differentiated and polarized cell morphology and ultrastructure with concomitant induction of the secretion of casein, lactoferrin. and alpha-lactalbumin in vitro, and that the non-coordinate regulation of milk protein secretion by substratum, prolactin, and serum likely involves alternate routing and control of secretion pathways for casein and lactoferrin.     

Heterocellular interaction enhances recruitment of alpha and beta-catenins and ZO-2 into functional gap-junction complexes and induces gap junction-dependant differentiation of mammary epithelial cells

Gap junctions (GJ) are required for mammary epithelial differentiation. Using epithelial (SCp2) and myoepithelial-like (SCg6) mouse-derived mammary cells, the role of heterocellular interaction in assembly of GJ complexes and functional differentiation (β-casein expression) was evaluated. Heterocellular interaction is critical for β-casein expression, independent of exogenous basement membrane or cell anchoring substrata. Functional differentiation of SCp2, co-cultured with SCg6, is more sensitive to GJ inhibition relative to homocellular SCp2 cultures differentiated by exogenous basement membrane. Connexin (Cx)32 and Cx43 levels were not regulated across culture conditions; however, GJ functionality was enhanced under differentiation-permissive conditions. Immunoprecipitation studies demonstrated association of junctional complex components (α-catenin, β-catenin and ZO−2) with Cx32 and Cx43, in differentiation conditions, and additionally with Cx30 in heterocellular cultures. Although β-catenin did not shuttle between cadherin and GJ complexes, increased association between connexins and β-catenin in heterocellular cultures was observed. This was concomitant with reduced nuclear β-catenin, suggesting that differentiation in heterocellular cultures involves sequestration of β-catenin in GJ complexes.     

A disposable electrochemical immunosensor for flow injection immunoassay of carcinoembryonic antigen

A new simple immunoassay method for carcinoembryonic antigen (CEA) detection using a disposable immunosensor coupled with a flow injection system was developed. The immunosensor was prepared by coating CEA/colloid Au/chitosan membrane at a screen-printed carbon electrode (SPCE). Using a competitive immunoassay format, the immunosensor inserted in the flow system with an injection of sample and horseradish peroxidase (HRP)-labeled CEA antibody was used to trap the labeled antibody at room temperature for 35 min. The current response obtained from the labeled HRP to thionine-H(2)O(2) system decreased proportionally to the CEA concentration in the range of 0.50-25 ng/ml with a correlation coefficient of 0.9981 and a detection limit of 0.22 ng/ml (S/N=3). The immunoassay system could automatically control the incubation, washing and current measurement steps with good stability and acceptable accuracy. Thus, the proposed method proved its potential use in clinical immunoassay of CEA.     

Methoxychlor-Induced Alterations in the Histological Expression of Angiogenic Factors in Pituitary and Uterus

Within the reproductive system, oestrogenic stimulation of uterine and pituitary tissue typically causes a proliferative response accompanied by an angiogenic induction of new blood vessels from existing ones, thereby providing nutrients and oxygen to the growing tissue. The pro-oestrogenic pesticide methoxychlor (MXC), however, has shown a differential effect on proliferative activity. An increase in uterine growth is present, while the pituitary undergoes a decrease in size, even though the effect is accompanied by a characteristic oestrogen-induced elevation in pituitary prolactin concentration. The focus of the current study was whether the observed differences in tissue growth between uterus and pituitary in response to MXC administration were paralleled by a corresponding disparity in the expression of those growth factors (members of the vascular endothelial growth factor (VEGF) and angiopoietin families and their receptors) that are involved in the angiogenic cascade. Ovariectomized adult Sprague-Dawley female rats were administered MXC (0-200 mg/kg, oral) for 1 or 3 weeks. Immunohistochemical staining of uteri and pituitaries was performed under strictly controlled conditions for VEGF and its receptor VEGFR2, Angiopoietin-1 (Ang1) and angiopoietin-2 and their tyrosine kinase receptor Tie2, and platelet endothelial adhesion factor (as an index of vascularity). Image acquisition and densitometric assessments of staining intensity were conducted under blind conditions. The results showed uterine MXC-induced increases in the expression of VEGFR2 and Ang1, changes consistent with a normal proliferative response to oestrogenic stimulation. For VEGF, staining tended to be most pronounced in the stromal region, although there did not appear to be a progressive increase with dose. VEGFR2 expression showed significant dose-related trends in luminal and glandular epithelia by 1 week. Similar effects at 1 week were evident for Ang1 in glandular epithelium. In the anterior pituitary, a dose-related increase in VEGF was present for the 1 and 3 week treatments, and the number of pituitary vessels per unit area was also increased after 3 weeks. The effects indicate that even though the insecticide has not been found to cause an augmentation in pituitary growth, a dose-related rise in the expression of at least one principal angiogenic factor is present that may be associated with an increase in vascular density.     

Granulocyte/macrophage colony-stimulating factor treatment improves alveolar epithelial barrier function in alcoholic rat lung

Chronic alcohol abuse increases the risk of developing acute lung injury approximately threefold in septic patients, and ethanol ingestion for 6 wk in rats impairs alveolar epithelial barrier function both in vitro and in vivo. Granulocyte/macrophage colony-stimulating factor (GM-CSF) is a trophic factor for the alveolar epithelium, and a recent phase II clinical study suggests that GM-CSF therapy decreases sepsis-mediated lung injury. Therefore, we hypothesized that GM-CSF treatment could improve ethanol-mediated defects in the alveolar epithelium during acute stresses such as endotoxemia. In this study, we determined that recombinant rat GM-CSF improved lung liquid clearance (as reflected by lung tissue wet:dry ratios) in ethanol-fed rats anesthetized and then challenged with 2 ml of saline via a tracheostomy tube. Furthermore, GM-CSF treatment improved lung liquid clearance and decreased epithelial protein leak in both control-fed and ethanol-fed rats after 6 h of endotoxemia induced by Salmonella typhimurium lipopolysaccharide given intraperitoneally, but with the greater net effect seen in the ethanol-fed rats. Our previous studies indicate that chronic ethanol ingestion decreases lung liquid clearance by increasing intercellular permeability. Consistent with this, GM-CSF treatment in vitro decreased permeability of alveolar epithelial monolayers derived from both control-fed and ethanol-fed rats. As in the endotoxemia model in vivo, the effect of GM-CSF was most dramatic in the ethanol group. Together, these results indicate that GM-CSF treatment has previously unrecognized effects in promoting alveolar epithelial barrier integrity and that these salutary effects may be particularly relevant in the setting of chronic alcohol abuse.     

Mass spectrometry-based proteomics combined with bioinformatic tools for bacterial classification

Timely classification and identification of bacteria is of vital importance in many areas of public health. We present a mass spectrometry (MS)-based proteomics approach for bacterial classification. In this method, a bacterial proteome database is derived from all potential protein coding open reading frames (ORFs) found in 170 fully sequenced bacterial genomes. Amino acid sequences of tryptic peptides obtained by LC-ESI MS/MS analysis of the digest of bacterial cell extracts are assigned to individual bacterial proteomes in the database. Phylogenetic profiles of these peptides are used to create a matrix of sequence-to-bacterium assignments. These matrixes, viewed as specific assignment bitmaps, are analyzed using statistical tools to reveal the relatedness between a test bacterial sample and the microorganism database. It is shown that, if a sufficient amount of sequence information is obtained from the MS/MS experiments, a bacterial sample can be classified to a strain level by using this proteomics method, leading to its positive identification.     

Effects of a WHO-guided digital health intervention for depression in Syrian refugees in Lebanon: A randomized controlled trial

BackgroundMost displaced people with mental disorders in low- and middle-income countries do not receive effective care, and their access to care has deteriorated during the Coronavirus Disease 2019 (COVID-19) pandemic. Digital mental health interventions are scalable when digital access is adequate, and they can be safely delivered during the COVID-19 pandemic. We examined whether a new WHO-guided digital mental health intervention, Step-by-Step, in which participants were supported by a nonspecialist helper, was effective in reducing depression among displaced people in Lebanon.Methods and findingsWe conducted a single-blind, 2-arm pragmatic randomized clinical trial, comparing guided Step-by-Step with enhanced care as usual (ECAU) among displaced Syrians suffering from depression and impaired functioning in Lebanon. Primary outcomes were depression (Patient Health Questionnaire, PHQ-9) and impaired functioning (WHO Disability Assessment Schedule-12, WHODAS) at posttreatment. Secondary outcomes included subjective well-being, anxiety, post-traumatic stress, and self-described problems. A total of 569 displaced people from Syria with depression (PHQ-9 ≥ 10) and impaired functioning (WHODAS > 16) were randomized to Step-by-Step (N = 283; lost to follow-up: N = 167) or ECAU (N = 286; lost to follow-up: 133). Participants were considered to be lost to follow-up when they did not fill in the outcome measures at posttest or follow-up. Recruitment started on December 9, 2019 and was completed on July 9, 2020. The last follow-up assessments were collected in December 2020. The study team had access to the online platform, where they could see treatment arm assignment for each participant. All questionnaires were completed by participants online. Intention-to-treat (ITT) analyses showed intervention effects on depression (standardized mean differences [SMDs]: 0.48; 95% CI: 0.26; 0.70; p < 0.001), impaired functioning (SMD: 0.35; 95% CI: 0.14; 0.56; p < 0.001), post-traumatic stress (SMD: 0.36; 95% CI: 0.16; 0.56; p < 0.001), anxiety (SMD: 0.46; 95% CI: 0.24; 0.68; p < 0.001), subjective well-being (SMD: 0.47; 95% CI: 0.26; 0.68; p < 0.001), and self-identified personal problems (SMD: 0.49; 95% CI 0.28; 0.70; p < 0.001). Significant effects on all outcomes were maintained at 3 months follow-up. During the trial, one serious adverse event occurred, unrelated to the intervention. The main limitation of the current trial is the high dropout rate.ConclusionsIn this study, we found that a guided, digital intervention was effective in reducing depression in displaced people in Lebanon. The guided WHO Step-by-Step intervention we examined should be made available to communities of displaced people that have digital access.Trial registrationClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT03720769","term_id":"NCT03720769"}}NCT03720769.

In a randomized controlled trial, Pim Cuijpers and colleagues evaluate the effects of the Step-by-Step guided digital mental health intervention on depression, impaired functioning, and other mental health outcomes among displaced Syrians living in Lebanon.     

Die Carex-Arten der Innsbrucker Flora

Ohne Zusammenfassung