The anatomy of the fruit in relation to the propensity of citrus species to split

The anatomy of the fruit has been compared in three prone-to-split mandarin hybrids (Nova, Ellendale and Murcott), several cultivars of clementine mandarin (Fino, Clementina de Nules and Orogrande), and in Owari satsuma mandarin. The fruit of the hybrids is oblate to subglobose and usually presents an open stylar end disrupted by a navel formed by the floral meristem, which is conserved near the apex of the fruit. In the non-prone-to-split clementines as well as in Owari satsuma, the floral axis protrudes inside the style, and the flower meristem is lost through abscission shortly after petal fall. The abaxial side of the carpels fuses with the flower axis forming at the stylar end of the fruit a solid tissue which externally has a small scar at the place of style abscission. Most of the fruits in these cultivars have no navel. In addition, the fruit of clementine is slightly oblate or globose. The relevance of these anatomical characteristics as regards to splitting is supported by the differences between the split and non-split fruits in Nova, the split fruit being more oblate in shape and having a bigger navel than non-split fruit. However, the effect of applied growth regulators on fruit splitting could not be correlated with their effect on the anatomy of the fruit. Additional factors not contemplated in the study also influence fruit splitting

Temperature Modulation of Electric Fields in Biological Matter

Pulsed electric fields (PEF) have become an important minimally invasive surgical technology for various applications including genetic engineering, electrochemotherapy and tissue ablation. This study explores the hypothesis that temperature dependent electrical parameters of tissue can be used to modulate the outcome of PEF protocols, providing a new means for controlling and optimizing this minimally invasive surgical procedure. This study investigates two different applications of cooling temperatures applied during PEF. The first case utilizes an electrode which simultaneously delivers pulsed electric fields and cooling temperatures. The subsequent results demonstrate that changes in electrical properties due to temperature produced by this configuration can substantially magnify and confine the electric fields in the cooled regions while almost eliminating electric fields in surrounding regions. This method can be used to increase precision in the PEF procedure, and eliminate muscle contractions and damage to adjacent tissues. The second configuration considered introduces a third probe that is not electrically active and only applies cooling boundary conditions. This second study demonstrates that in this probe configuration the temperature induced changes in electrical properties of tissue substantially reduce the electric fields in the cooled regions. This novel treatment can potentially be used to protect sensitive tissues from the effect of the PEF. Perhaps the most important conclusion of this investigation is that temperature is a powerful and accessible mechanism to modulate and control electric fields in biological tissues and can therefore be used to optimize and control PEF treatments

Calcium electroporation and electrochemotherapy for cancer treatment:Importance of cell membrane composition investigated by lipidomics, calorimetry and in vitro efficacy

Abstract Calcium electroporation is a novel anti-cancer treatment investigated in clinical trials. We explored cell sensitivity to calcium electroporation and electroporation with bleomycin, using viability assays at different time and temperature points, as well as heat calorimetry, lipidomics, and flow cytometry. Three cell lines: HT29 (colon cancer), MDA-MB231 (breast cancer), and HDF-n (normal fibroblasts) were investigated for; (a) cell survival dependent on time of addition of drug relative to electroporation (1.2 kV/cm, 8 pulses, 99 µs, 1 Hz), at different temperatures (37 °C, 27 °C, 17 °C); (b) heat capacity profiles obtained by differential scanning calorimetry without added calcium; (c) lipid composition by mass spectrometry; (d) phosphatidylserine in the plasma membrane outer leaflet using flow cytometry. Temperature as well as time of drug administration affected treatment efficacy in HT29 and HDF-n cells, but not MDA-MB231 cells. Interestingly the HT29 cell line displayed a higher phase transition temperature (approximately 20 °C) versus 14 °C (HDF-n) and 15 °C (MDA-MB231). Furthermore the HT29 cell membranes had a higher ratio of ethers to esters, and a higher expression of phosphatidylserine in the outer leaflet. In conclusion, lipid composition and heat capacity of the membrane might influence permeabilisation of cells and thereby the effect of calcium electroporation and electrochemotherapy

Electropermeabilization of endocytotic vesicles in B16 F1 mouse melanoma cells

It has been reported previously that electric pulses of sufficiently high voltage and short duration can permeabilize the membranes of various organelles inside living cells. In this article, we describe electropermeabilization of endocytotic vesicles in B16 F1 mouse melanoma cells. The cells were exposed to short, high-voltage electric pulses (from 1 to 20 pulses, 60 ns, 50 kV/cm, repetition frequency 1 kHz). We observed that 10 and 20 such pulses induced permeabilization of membranes of endocytotic vesicles, detected by release of lucifer yellow from the vesicles into the cytosol. Simultaneously, we detected uptake of propidium iodide through plasma membrane in the same cells. With higher number of pulses permeabilization of the membranes of endocytotic vesicles by pulses of given parameters is accompanied by permeabilization of plasma membrane. However, with lower number of pulses only permeabilization of the plasma membrane was detected

El rajado estilar del fruto en los citricos: aspectos anatomicos y morfologicos

El rajado o agrietado es una alteración del fruto, y aun de otras partes utilizables de la planta, que se caracteriza por la formación de fisuras profundas en la piel o corteza de tal modo que la parte interna comestible del fruto queda expuesta y aun se agrieta. El fruto afectado en muchos casos se desprende prematuramente, pero aun en el caso de que complete su desarrollo y alcance la maduración es inservible para la comercialización. Esta alteración se ha descrito en gran número de especies, entre las que se encuentran frutales de hueso y de pepita, plantas hortícolas (como el tomate) y los cítricos, provocando a menudo pérdidas económicas importantes. Las características de la misma han sido revisadas de modo crítico recientemente por Opara y col. (1997), que resaltan los aspectos siguientes: a) Existe un factor genético en la predisposición a la presencia de esta alteración, mucho más frecuente en algunos cultivares de cada una de las especies; b) Hay una variación marcada en la susceptibilidad a la misma entre árboles y entre frutos de un mismo árbol; c) La alteración es afectada por factores ambientales, de tal modo que su incidencia varía notablemente de un año a otro y entre parcelas de la misma especie; d) No hay un factor causal único de la alteración, y e) Las prácticas correctivas desarrolladas son de resultado errático, variando su eficacia de modo marcado sin que sea posible establecer una pauta de respuesta definida. La influencia de estos factores en la incidencia del rajado en los cítricos son evidentes. La alteración es frecuente en los cultivares Nova, Murcott y Ellendale, mientras se presenta raramente en satsumas y clementinas. Para una misma variedad el porcentaje de rajado varía notablemente entre parcelas y, en una misma parcela, de un año a otro, siendo en general más elevado en regiones cálidas y húmedas, factores climáticos que favorecen la formación de frutos de piel fina (Alexander, 1983; Robe and Van Rensburg, 1996). Probablemente las diferencias climáticas son responsables del comportamiento diferente de algunas variedades en distintas regiones citrícolas, como ocurre con las variedades del tipo navel, que en Florida presentan un porcentaje significativo de frutos rajados mientras en las condiciones de Valencia el rajado del fruto no tiene normalmente importancia, así como de las diferencias en comportamiento en una misma región en años diferentes. Es notable al respecto que el tangor Ortanique, que en las condiciones de Valencia normalmente no se raja, ha presentado este año en algunas parcelas un porcentaje de rajado superior al 40%.info:eu-repo/semantics/publishedVersio

Effect of different parameters used for in vitro gene electrotransfer on gene expression efficiency, cell viability and visualization of plasmid DNA at the membrane level

International audienc

Electro-mediated gene transfer and expression are controlled by the life-time of DNA/membrane complex formation

International audienc