Salinity Stress and Salt Tolerance

"Salinity is one of the most serious factors limiting the productivity of agricultural crops, with adverse effects on germination, plant vigour and crop yield (R Munns & Tester, 2008). Salinization affects many irrigated areas mainly due to the use of brackish water. Worldwide, more than 45 million hectares of irrigated land have been damaged by salt, and 1.5 million hectares are taken out of production each year as a result of high salinity levels in the soil (R Munns & Tester, 2008). High salinity affects plants in several ways: water stress, ion toxicity, nutritional disorders, oxidative stress, alteration of metabolic processes, membrane disorganization, reduction of cell division and expansion, genotoxicity (Hasegawa, Bressan, Zhu, & Bohnert, 2000, R. Munns, 2002, Zhu, 2007). Together, these effects reduce plant growth, development and survival.

Durum wheat roots adapt to salinity remodeling the cellular content of nitrogen metabolites and sucrose

Plants are currently experiencing increasing salinity problems due to irrigation with brackish water. Moreover, in fields, roots can grow in soils which show spatial variation in water content and salt concentration, also because of the type of irrigation. Salinity impairs crop growth and productivity by inhibiting many physiological and metabolic processes, in particular nitrate uptake, translocation, and assimilation. Salinity determines an increase of sap osmolality from about 305 mOsmol kg-1 in control roots to about 530 mOsmol kg-1 in roots under salinity. Root cells adapt to salinity by sequestering sodium in the vacuole, as a cheap osmoticum, and showing a rearrangement of few nitrogencontaining metabolites and sucrose in the cytosol, both for osmotic adjustment and oxidative stress protection, thus providing plant viability even at low nitrate levels. Mainly glycine betaine and sucrose at low nitrate concentration, and glycine betaine, asparagine and proline at high nitrate levels can be assumed responsible for the osmotic adjustment of the cytosol, the assimilation of the excess of ammonium and the scavenging of ROS under salinity. High nitrate plants with half of the root system under salinity accumulate proline and glutamine in both control and salt stressed split roots, revealing that osmotic adjustment is not a regional effect in plants. The expression level and enzymatic activities of asparagine synthetase and δ1-pyrroline-5-carboxylate synthetase, as well as other enzymatic activities of nitrogen and carbon metabolism, are analyzed

Ty1-copia group retrotransposons and the evolution of retroelements in several angiosperm plants: evidence of horizontal transmission

The phylogenetic relationships among thirty-seven new Ty1-copia group retrotransposons in seven angiosperm plants were examined by reverse transcriptase and ribonuclease H sequence analysis. Distribution pattern of the retrotransposons of closely related plant species generally reflects a close phylogenetic relationship. In contrast, we found that several retrotransposon sequences from the same genome exhibited a high degree of divergence and had a relatively high degree of identity versus retrotransposon sequences from widely divergent species, including an ancestral phytopathogen fungus. This finding supports the hypothesis that the horizontal transmission from phytopatogen organism to the host flowering plants could have played a role in the evolutionary dynamics of Ty1-copia group retrotransposons

Spatial and Temporal Profile of Glycine Betaine Accumulation in Plants Under Abiotic Stresses

Several halophytes and a few crop plants, including Poaceae, synthesize and accumulate glycine betaine (GB) in response to environmental constraints. GB plays an important role in osmoregulation, in fact, it is one of the main nitrogen-containing compatible osmolytes found in Poaceae. It can interplay with molecules and structures, preserving the activity of macromolecules, maintaining the integrity of membranes against stresses and scavenging ROS. Exogenous GB applications have been proven to induce the expression of genes involved in oxidative stress responses, with a restriction of ROS accumulation and lipid peroxidation in cultured tobacco cells under drought and salinity, and even stabilizing photosynthetic structures under stress. In the plant kingdom, GB is synthesized from choline by a two-step oxidation reaction. The first oxidation is catalyzed by choline monooxygenase (CMO) and the second oxidation is catalyzed by NAD+-dependent betaine aldehyde dehydrogenase. Moreover, in plants, the cytosolic enzyme, named N-methyltransferase, catalyzes the conversion of phosphoethanolamine to phosphocholine. However, changes in CMO expression genes under abiotic stresses have been observed. GB accumulation is ontogenetically controlled since it happens in young tissues during prolonged stress, while its degradation is generally not significant in plants. This ability of plants to accumulate high levels of GB in young tissues under abiotic stress, is independent of nitrogen (N) availability and supports the view that plant N allocation is dictated primarily to supply and protect the growing tissues, even under N limitation. Indeed, the contribution of GB to osmotic adjustment and ionic and oxidative stress defense in young tissues, is much higher than that in older ones. In this review, the biosynthesis and accumulation of GB in plants, under several abiotic stresses, were analyzed focusing on all possible roles this metabolite can play, particularly in young tissues

Nutrient Solution Deprivation as a Tool to Improve Hydroponics Sustainability: Yield, Physiological, and Qualitative Response of Lettuce

Hydroponics growing systems often contain excessive nutrients (especially nitrates), which could lead to a quality loss in ready-to-eat leafy vegetables and posing a health risk to consumers, if managed inadequately. A floating raft system was adopted to assay the production and quality performance of lettuce (Lactuca sativa L. cv ‘Maravilla De Verano Canasta’) deprived of the nutrient solution by replacement with only water, three and six days before harvest. Yield and quality parameters, mineral composition, pigments, organic acids, amino acids profile, soluble proteins, and carbohydrate content were determined. Nutrient solution deprivation six days before harvest resulted in a significant reduction in leaf nitrate (−53.3%) concomitant with 13.8% of yield loss, while plants deprived of nutrient solution three days before harvest increased total phenols content (32.5%) and total ascorbic acid (102.1%), antioxidant activity (82.7%), anthocyanins (7.9%), sucrose (38.9%), starch (19.5%), and γ-aminobutyric acid (GABA; 28.2%), with a yield reduction of 4.7%, compared to the control. Our results suggest that nutrient solution deprivation three days before harvest is a successful strategy to reduce nitrate content and increase the nutritional quality of lettuce grown in floating raft systems with negligible impact on yield. These promising results warrant further investigation of the potential effect of nutrient solution deprivation on the quality attributes of other leafy vegetables cultivated in floating raft systems and in a “cascade” growing system

Integrated Model of Chemical Perturbations of a Biological Pathway Using 18 In Vitro High Throughput Screening Assays for the Estrogen Receptor

We demonstrate a computational network model that integrates 18 in vitro, high-throughput screening assays measuring estrogen receptor (ER) binding, dimerization, chromatin binding, transcriptional activation and ER-dependent cell proliferation. The network model uses activity patterns across the in vitro assays to predict whether a chemical is an ER agonist or antagonist, or is otherwise influencing the assays through a manner dependent on the physics and chemistry of the technology platform (“assay interference”). The method is applied to a library of 1812 commercial and environmental chemicals, including 45 ER positive and negative reference chemicals. Among the reference chemicals, the network model correctly identified the agonists and antagonists with the exception of very weak compounds whose activity was outside the concentration range tested. The model agonist score also correlated with the expected potency class of the active reference chemicals. Of the 1812 chemicals evaluated, 111 (6.1%) were predicted to be strongly ER active in agonist or antagonist mode. This dataset and model were also used to begin a systematic investigation of assay interference. The most prominent cause of false-positive activity (activity in an assay that is likely not due to interaction of the chemical with ER) is cytotoxicity. The model provides the ability to prioritize a large set of important environmental chemicals with human exposure potential for additional in vivo endocrine testing. Finally, this model is generalizable to any molecular pathway for which there are multiple upstream and downstream assays available

Reintroducing face-to-face support alongside remote support to form a hybrid stop smoking service in England: a formative mixed methods evaluation

Background: During the COVID-19 pandemic, United Kingdom (UK) stop smoking services had to shift to remote delivery models due to social distancing regulations, later reintroducing face-to-face provision. The “Living Well Smokefree” service in North Yorkshire County Council adopted a hybrid model offering face-to-face, remote, or a mix of both. This evaluation aimed to assess the hybrid approach’s strengths and weaknesses and explore potential improvements. Methods: Conducted from September 2022 to February 2023, the evaluation consisted of three components. First, qualitative interviews involved 11 staff and 16 service users, analysed thematically. Second, quantitative data from the QuitManager system that monitored the numbers and proportions of individuals selecting and successfully completing a 4-week quit via each service option. Third, face-to-face service expenses data was used to estimate the value for money of additional face-to-face provision. The qualitative findings were used to give context to the quantitative data via an “expansion” approach and complementary analysis. Results: Overall, a hybrid model was seen to provide convenience and flexible options for support. In the evaluation, 733 individuals accessed the service, with 91.3% selecting remote support, 6.1% face-to-face, and 2.6% mixed provision. Remote support was valued by service users and staff for promoting openness, privacy, and reducing stigma, and was noted as removing access barriers and improving service availability. However, the absence of carbon monoxide monitoring in remote support raised accountability concerns. The trade-off in “quantity vs. quality” of quits was debated, as remote support reached more users but produced fewer carbon monoxide-validated quits. Primarily offering remote support could lead to substantial workloads, as staff often extend their roles to include social/mental health support, which was sometimes emotionally challenging. Offering service users a choice of support options was considered more important than the “cost-per-quit”. Improved dissemination of information to support service users in understanding their options for support was suggested. Conclusions: The hybrid approach allows smoking cessation services to evaluate which groups benefit from remote, face-to-face, or mixed options and allocate resources accordingly. Providing choice, flexible provision, non-judgmental support, and clear information about available options could improve engagement and match support to individual needs, enhancing outcomes

Knowledge and attitudes of primary health care physicians and nurses with regard to population screening for colorectal cancer in Balearic Islands and Barcelona

<p>Abstract</p> <p>Background</p> <p>Primary health care (PHC) professionals play a key role in population screening of colorectal cancer. The purposes of the study are: to assess knowledge and attitudes among PHC professionals with regard to colorectal cancer screening, as well as the factors that determine their support for such screening.</p> <p>Methods</p> <p>Questionnaire-based survey of PHC physicians and nurses in the Balearic Islands and in a part of the metropolitan area of Barcelona.</p> <p>Results</p> <p>We collected 1,219 questionnaires. About 84% of all professionals believe that screening for colorectal cancer by fecal occult blood test (FOBT) is effective. Around 68% would recommend to their clients a colorectal cancer screening program based on FOBT and colonoscopy. About 31% are reluctant or do not know. Professionals perceive the fear of undergoing a colonoscopy as the main obstacle in getting patients to participate, and the invasive nature of this test is the main reason behind their resistance to this program. The main barriers to support the screening program among PHC professionals are lack of knowledge (nurses) and lack of time (physicians). On multivariate analysis, the factors associated with reluctance to recommend colorectal cancer screening were: believing that FOBT has poor sensitivity and is complicated; that colonoscopy is an invasive procedure; that a lack of perceived benefit could discourage client participation; that only a minority of clients would participate; thinking that clients are fed up with screening tests and being unaware if they should be offered something to ensure their participation in the programme.</p> <p>Conclusions</p> <p>Two in every three PHC professionals would support a population screening program for colorectal cancer screening. Factors associated with reluctance to recommend it were related with screening tests characteristics as sensitivity and complexity of FOBT, and also invasive feature of colonoscopy. Other factors were related with patients' believes.</p

Phase I Randomised Clinical Trial of an HIV-1CN54, Clade C, Trimeric Envelope Vaccine Candidate Delivered Vaginally

We conducted a phase 1 double-blind randomised controlled trial (RCT) of a HIV-1 envelope protein (CN54 gp140) candidate vaccine delivered vaginally to assess immunogenicity and safety. It was hypothesised that repeated delivery of gp140 may facilitate antigen uptake and presentation at this mucosal surface. Twenty two healthy female volunteers aged 18–45 years were entered into the trial, the first receiving open-label active product. Subsequently, 16 women were randomised to receive 9 doses of 100 µg of gp140 in 3 ml of a Carbopol 974P based gel, 5 were randomised to placebo solution in the same gel, delivered vaginally via an applicator. Participants delivered the vaccine three times a week over three weeks during one menstrual cycle, and were followed up for two further months. There were no serious adverse events, and the vaccine was well tolerated. No sustained systemic or local IgG, IgA, or T cell responses to the gp140 were detected following vaginal immunisations. Repeated vaginal immunisation with a HIV-1 envelope protein alone formulated in Carbopol gel was safe, but did not induce local or systemic immune responses in healthy women

Transient Facial Nerve Paralysis (Bell's Palsy) following Intranasal Delivery of a Genetically Detoxified Mutant of Escherichia coli Heat Labile Toxin

BACKGROUND: An association was previously established between facial nerve paralysis (Bell's palsy) and intranasal administration of an inactivated influenza virosome vaccine containing an enzymatically active Escherichia coli Heat Labile Toxin (LT) adjuvant. The individual component(s) responsible for paralysis were not identified, and the vaccine was withdrawn. METHODOLOGY/PRINCIPAL FINDINGS: Subjects participating in two contemporaneous non-randomized Phase 1 clinical trials of nasal subunit vaccines against Human Immunodeficiency Virus and tuberculosis, both of which employed an enzymatically inactive non-toxic mutant LT adjuvant (LTK63), underwent active follow-up for adverse events using diary-cards and clinical examination. Two healthy subjects experienced transient peripheral facial nerve palsies 44 and 60 days after passive nasal instillation of LTK63, possibly a result of retrograde axonal transport after neuronal ganglioside binding or an inflammatory immune response, but without exaggerated immune responses to LTK63. CONCLUSIONS/SIGNIFICANCE: While the unique anatomical predisposition of the facial nerve to compression suggests nasal delivery of neuronal-binding LT-derived adjuvants is inadvisable, their continued investigation as topical or mucosal adjuvants and antigens appears warranted on the basis of longstanding safety via oral, percutaneous, and other mucosal routes