Effect of Thiourea on Yield and Quality of Potato (Solanum tuberosum L.)

A field experiment was carried out to study the effect of five concentrations (0, 250, 500, 750 and 1000 mM) of thiourea application on mother tubers on yield and quality attributes of harvested potato, variety Spunta in the region of Chott-Mariem in Tunisia. Treated tubers (Ш = 50 mm) were planted in field after breaking dormancy at a spacing of 80 cm x 30 cm according to completely randomized design (CRD) in three replications. Quality attributes of potato tubers especially fresh matter and dry matter of plant, total reducing sugars in leaves, tuber yield, number and diameter of tubers per plant and number of sprouts per tuber was measured. Soluble proteins and starch content in potato tubers were also quantified.In general we noted that application of thiourea showed significant influence on yield and on quality of tubers comparing to control. Maximum tuber yield per plant, maximum number of tubers per plant and maximum starch content was recorded with 250 mM of thiourea. Moreover, highest dry matter of potato plant was found also at this concentration. While increasing dose of thiourea thereafter it showed slight significant improvement and do not affect significantly the diameter of tubers comparing to control

PHYSIOLOGICAL MECHANISMS FOR POTATO DORMANCY RELEASE AND SPROUTING: A REVIEW

Potato ( Solanum tuberosum \ua0L.) tubers undergo a period of dormancy, during which visible bud growth is inhibited. The length of the dormancy is determined by environmental, physiological and hormonal control mechanisms. Dormancy is the final stage of tuber life, which serves to preserve tubers as organs of vegetative reproduction under unfavourable growth conditions. Since the duration of potato tuber dormancy and sprouting time bear significant economic importance, this review considers the regulation of dormancy and sprouting of potato by phytohormones and reactive oxygen species. Two phytohormones, ABA and ethylene suppress tuber sprouting; however, the exact role of ethylene remains to be elucidated. Cytokinins and gibberellins are required for bud breaking and sprout growth, respectively. The auxin seems to play a role in vascular development. Thus, tuber dormancy and sprouting can be controlled in potato by manipulation of Reactive Oxygen Species (ROS), especially H2O2\ua0metabolism via the inhibition of catalase (CAT) activity.The possible mechanisms by which CAT inhibitors or H2O2\ua0overcome dormancy and promote sprouting in the potato tuber are discussed.La pomme de terre ( Solanum tuberosum \ua0L.) conna\ueet une p\ue9riode de dormance durant laquelle la germination des bourgeons visibles est inhib\ue9e. La dur\ue9e de dormance est d\ue9termin\ue9e par des m\ue9canismes de contr\uf4le environnemental, physiologique and hormonal. La dormance est le stade final de la vie des tubercules servant \ue0 pr\ue9server les tubercules comme organes de reproduction v\ue9g\ue9tative sous condition de germination d\ue9favorables. Etant donn\ue9 que la dur\ue9e de la dormance des tubercules de la pomme de terre et le temps de rejet rev\ueatent une importance \ue9conomique significative, cette revue consid\ue8re la r\ue9gulation de la dormance et le rejet de la pomme de terre par des hormones et d\u2019esp\ue8ces r\ue9actives d\u2019oxyg\ue8ne (ROS). Deux phytohormones\ua0; ABA et \ue9thyl\ue8ne emp\ueachent le rejet des tubercules\ua0; par ailleurs, le r\uf4le extractif de l\u2019\ue9thyl\ue8ne reste \ue0 \ue9lucider. Les cytokinines and les gibb\ue9rellines sont n\ue9cessaires dans l\u2019\ue9limination des bourgeons et la croissance des rejets, respectivement. L\u2019auxine semble jouer un r\uf4le dans le d\ue9veloppement vasculaire. Ainsi, la dormance et les rejets des tubercules peuvent \ueatre contr\uf4l\ue9s par manipulation d\u2019esp\ue8ces r\ue9actives d\u2019oxyg\ue8ne (ROS), sp\ue9cialement le m\ue9tabolisme du H2O2\ua0\ue0 travers l\u2019inhibition de l\u2019activit\ue9 de la catalase (CAT). Les m\ue9canismes possibles par lesquels les inhibiteurs du CAT ou H2O2\ua0 surmontent la dormance et facilitent le rejet de la pomme de terre sont discut\ue9s

Simian Immunodeficiency Virus Infection of Chimpanzees (Pan troglodytes) Shares Features of Both Pathogenic and Non-pathogenic Lentiviral Infections.

The virus-host relationship in simian immunodeficiency virus (SIV) infected chimpanzees is thought to be different from that found in other SIV infected African primates. However, studies of captive SIVcpz infected chimpanzees are limited. Previously, the natural SIVcpz infection of one chimpanzee, and the experimental infection of six chimpanzees was reported, with limited follow-up. Here, we present a long-term study of these seven animals, with a retrospective re-examination of the early stages of infection. The only clinical signs consistent with AIDS or AIDS associated disease was thrombocytopenia in two cases, associated with the development of anti-platelet antibodies. However, compared to uninfected and HIV-1 infected animals, SIVcpz infected animals had significantly lower levels of peripheral blood CD4+ T-cells. Despite this, levels of T-cell activation in chronic infection were not significantly elevated. In addition, while plasma levels of β2 microglobulin, neopterin and soluble TNF-related apoptosis inducing ligand (sTRAIL) were elevated in acute infection, these markers returned to near-normal levels in chronic infection, reminiscent of immune activation patterns in 'natural host' species. Furthermore, plasma soluble CD14 was not elevated in chronic infection. However, examination of the secondary lymphoid environment revealed persistent changes to the lymphoid structure, including follicular hyperplasia in SIVcpz infected animals. In addition, both SIV and HIV-1 infected chimpanzees showed increased levels of deposition of collagen and increased levels of Mx1 expression in the T-cell zones of the lymph node. The outcome of SIVcpz infection of captive chimpanzees therefore shares features of both non-pathogenic and pathogenic lentivirus infections.This work was supported by the Biotechnology and Biological Sciences Research Council and by the Wellcome Trust.This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/10.1371/journal.ppat.100514

Concurrent regulation of LKB1 and CaMKK2 in the activation of AMPK in castrate-resistant prostate cancer by a well-defined polyherbal mixture with anticancer properties

Abstract Background Zyflamend, a blend of herbal extracts, effectively inhibits tumor growth using preclinical models of castrate-resistant prostate cancer mediated in part by 5′-adenosine monophosphate-activated protein kinase (AMPK), a master energy sensor of the cell. Clinically, treatment with Zyflamend and/or metformin (activators of AMPK) had benefits in castrate-resistant prostate cancer patients who no longer responded to treatment. Two predominant upstream kinases are known to activate AMPK: liver kinase B1 (LKB1), a tumor suppressor, and calcium-calmodulin kinase kinase-2 (CaMKK2), a tumor promotor over-expressed in many cancers. The objective was to interrogate how Zyflamend activates AMPK by determining the roles of LKB1 and CaMKK2. Methods AMPK activation was determined in CWR22Rv1 cells treated with a variety of inhibitors of LKB1 and CaMKK2 in the presence and absence of Zyflamend, and in LKB1-null HeLa cells that constitutively express CaMKK2, following transfection with wild type LKB1 or catalytically-dead mutants. Upstream regulation by Zyflamend of LKB1 and CaMKK2 was investigated targeting protein kinase C-zeta (PKCζ) and death-associated protein kinase (DAPK), respectively. Results Zyflamend’s activation of AMPK appears to be LKB1 dependent, while simultaneously inhibiting CaMKK2 activity. Zyflamend failed to rescue the activation of AMPK in the presence of pharmacological and molecular inhibitors of LKB1, an effect not observed in the presence of inhibitors of CaMKK2. Using LKB1-null and catalytically-dead LKB1-transfected HeLa cells that constitutively express CaMKK2, ionomycin (activator of CaMKK2) increased phosphorylation of AMPK, but Zyflamend only had an effect in cells transfected with wild type LKB1. Zyflamend appears to inhibit CaMKK2 by DAPK-mediated phosphorylation of CaMKK2 at Ser511, an effect prevented by a DAPK inhibitor. Alternatively, Zyflamend mediates LKB1 activation via increased phosphorylation of PKCζ, where it induced translocation of PKCζ and LKB1 to their respective active compartments in HeLa cells following treatment. Altering the catalytic activity of LKB1 did not alter this translocation. Discussion Zyflamend’s activation of AMPK is mediated by LKB1, possibly via PKCζ, but independent of CaMKK2 by a mechanism that appears to involve DAPK. Conclusions Therefore, this is the first evidence that natural products simultaneously and antithetically regulate upstream kinases, known to be involved in cancer, via the activation of AMPK.https://deepblue.lib.umich.edu/bitstream/2027.42/144515/1/12906_2018_Article_2255.pd

The Regulation of Ion Homeostasis, Growth, and Biomass Allocation in Date Palm Ex Vitro Plants Depends on the Level of Water Salinity

The date palm, a central plant in the fragile oasis ecosystem, is considered one of the fruit species most tolerant to salt stress. However, the tolerance mechanisms involved are yet to be addressed and their evaluation until now was mainly based on heterogenous plant material such as seedlings or limited to in vitro experiment conditions. For these reasons, we propose to deepen our knowledge of the morphological and physiological responses to salt stress using acclimated ex vitro plants resulting from the propagation of a single genotype. The plants were irrigated with 0, 150, 300, or 450 mM NaCl solutions for four months. Our results showed that the influence of water salinity on growth and ion-homeostasis regulation was very dependent on stress levels. The 150 mM NaCl concentration was found to improve dry biomass by about 35%, but at higher salt concentrations (300 and 450 mM) it decreased by 40–65%. The shoot:root dry mass ratio decreased significantly at the 150 mM NaCl water concentration and then increased with increasing water salt concentration. The leaf:root ratio for Na+ and Cl− decreased significantly with increasing water salinity up to a concentration of 300 mM NaCl, and then stabilized with similar values for 300 mM and 450 mM NaCl. In contrast to Na+ and Cl−, leaf K+ content was significantly higher in the leaf than in the root for all salt treatments. Unlike Na+ and K+, Cl− was expelled to the surface of leaves in response to increased water salinity. Overall, date palm plants appear to be more capable of excluding Cl− than Na+ and of changing biomass allocation according to salt-stress level, and their leaves and roots both appear to play an important role in this tolerance strategy.All authors are funded through the Small Research group project from the Deanship of Scientific Research at King Khalid University under research grant number (R.G.P.1/295/43).Peer reviewe

Zn treatment effects on biological potential of fennel bulbs as affected by in vitro digestion process

Zn treatment effects on the stability of polyphenols, MDA (malondialdehyde) content, antioxidant and lipoxygenase inhibition activities of two varieties of fennel bulbs were studied by using an in vitro gastrointestinal digestion model. Likewise, the effect of Zn on viability cells of E. coli was also performed. The results revealed that high amounts of total phenolic and flavonoid compounds were released during the digestion process, especially after the intestinal phase. Additionally, the antioxidant and lipoxygenase inhibitory activity were affected by the gastrointestinal digestion process and seems to be correlated with total phenol contents. On the other hand, the viability of E. coli was not affected by the activity of our tested bulbs during passage through the artificial digestion model, but the treated bulbs activity contribute relatively to the inhibition growth of bacteria. The survival of E. coli in fennel bulbs was challenged with simulated gastrointestinal fluids and the results showed that the E. coli strains, despite having experienced a viability reduction at the intestinal phase, were able to overcome the exposure to the gastrointestinal synthetic fluids. This E. coli ability reinforces the need for good hygienic measures to assure safe fresh produce, even for those that are rich in antibacterial compounds.info:eu-repo/semantics/publishedVersio

Differential effect of water salinity levels on gas exchange, chlorophyll fluorescence and antioxidant compounds in ex vitro date palm plants

In this study, the response to salt stress was evaluated in ex vitro acclimated date palm plants, regenerated from in vitro culture multiplication. The plants, eighteen-month-old, were irrigated with 0 (control), 150, 300 or 450 mM NaCl solutions (high to very high-water salinity). Photosynthesis parameters and antioxidant compounds were determined at the end of the experiment in leaves. At 150 mM NaCl, net CO2 assimilation rate and internal CO2 concentration were not impaired; while transpiration and stomatal conductance decreased by 60 and 70%, respectively. By increasing salt concentrations, all gas exchanges parameters were decreased. Measurement of chlorophyll fluorescence and P700 redox state showed that PSII and PSI machineries were significantly enhanced under 150 mM NaCl, conditions. With the 300 mM NaCl, the PSI parameters remained unchanged compared to control, while some of the PSII parameters, such as NPQ and Y (NPQ), were increased. At 450 mM NaCl, photosystems functionality was light intensity (PAR) dependent. Only at low PAR, a significant increase of some PSI and PSII parameters was observed. At the contrary, with high PAR, most of the energy conversion functions were significantly reduced, especially those related to PSI, indicating that PSI was more susceptible for damage by salinity than PSII. To overcome high salinity stress, ex vitro date palm plants mobilized a cascade of physio-biochemical pathways including the antioxidant activity and proline biosynthesis. Overall, the salinity of irrigation water, and up to 150 mM, improves the physiological performance of ex vitro date palm plants, which manage to tolerate very high levels of this stress.The authors extend their appreciation to the Deanship of Scientific Research at King Khalid University for funding this work through the large research Groups projects (Project under grant number (RGP. 2/73/44)).Peer reviewe

Spinal cystic echinococcosis - a systematic analysis and review of the literature : part 1. Epidemiology and anatomy

Bone involvement in human cystic echinococcosis (CE) is rare, but affects the spine in approximately 50% of cases. Despite significant advances in diagnostic imaging techniques as well as surgical and medical treatment of spinal CE, our basic understanding of the parasite's predilection for the spine remains incomplete. To fill this gap, we systematically reviewed the published literature of the last five decades to summarize and analyze the currently existing data on epidemiological and anatomical aspects of spinal CE

Users' role in applying biophilic attributes to the interiors of residential spaces

PurposeStudies related to biophilic design (BD) have not clarified the user's role in applying its elements and features to improve quality of life (physical and mental health). This paper aims to highlight the users' role (experience, practice, and advice) when utilising aspects of BD in the interior environment of modern houses (MH) in Jeddah, Saudi Arabia, as a case study.Design/methodology/approachA study of users' experiences was conducted through a qualitative approach by analysing semi-structured one-to-one interviews with a representative sample from Jeddah (12 heads of the family) using an adapted Biophilic Interior Design Matrix. An inductive approach was applied by extrapolating the users' role in employing BD elements in the MH's interior environment based on their experience in employing various biophilic elements.FindingsThe findings demonstrate the importance of the user's role when incorporating biophilic elements in living spaces. The levels of employment of BD elements of various kinds in the interior environment of the MH as a whole are considered high. A high percentage was observed regarding the availability of BD elements in the 40–59 years age group (87%), and a relationship was observed between housing type (villas vs apartments) and availability of BD elements. Additionally, a relationship was observed between the use of a professional designer when designing the house and the availability of biophilic elements. However, the sample did not have a grasp of several BD concepts. The application is generally made without knowing the positive impact on mental health. The user matrix was compiled as a reference that reflects the features and elements that are easily enjoyed in activating BD and enhancing the users' role in raising the level of BD in their homes. An initial classification of BD features was elaborated regarding the physical structure (PS) of a building, features regarding the user under control (UUC) and features regarding the user out of control (UOC).Research limitations/implicationsThe classification was preliminarily based on PS, UUC, and UOC. Future research is required to confirm what has been communicated through advanced and in-depth research for housing analysis to confirm and enhance the user's role. This approach is a quick alternative solution to employ biophilic elements.Originality/valueThe authors focussed on the immaterial aspect of BD in interior spaces from the user's experience. BD-related studies have focussed on the physical aspect of architectural space.</jats:sec