Drosophila melanogaster prefers compounds perceived sweet by humans

To understand the functional similarities of fly and mammalian taste receptors, we used a top-down approach that first established the fly sweetener-response profile. We employed the fruit fly Drosophila melanogaster, an omnivorous human commensal, and determined its sensitivity to an extended set of stimuli that humans find sweet. Flies were tested with all sweeteners in 2 assays that measured their taste reactivity (proboscis extension assay) and their ingestive preferences (free roaming ingestion choice test). A total of 21 sweeteners, comprised of 11 high-potency sweeteners, 2 amino acids, 5 sugars, 2 sugar alcohols, and a sweet salt (PbCl2), were tested in both assays. We found that wild-type Drosophila responded appetitively to most high-potency sweeteners preferred by humans, even those not considered sweet by rodents or new world monkeys. The similarities in taste preferences for sweeteners suggest that frugivorous/omnivorous apes and flies have evolved promiscuous carbohydrate taste detectors with similar affinities for myriad high-potency sweeteners. Whether these perceptual parallels are the result of convergent evolution of saccharide receptor-binding mechanisms remains to be determined.     

Tear cytokine and ocular surface alterations following brief passive cigarette smoke exposure

Purpose: To prospectively investigate the effects of acute passive cigarette smoke exposure on the ocular surface and tear film in healthy non-smokers. Methods: Twelve right eyes of 12 subjects without any ocular diseases were examined before, 5 min, and 24 h after 5 min of passive cigarette smoke exposure in a controlled smoke chamber. Tear samples were obtained before, 5 min and 24 h after smoke exposure to detect tear hexanoyl-lysine (HEL), acrolein and inflammatory cytokine concentrations. Tear evaporation rate, DR-1 tear film lipid layer interferometry, tear film break-up time (TBUT), ocular surface fluorescein staining (FS) and Rose Bengal staining (RB), Schirmer I test were performed before, 5 min, and 24 h after smoke exposure. Conjunctival impression cytology (IC) and brush cytology (BC) were carried out before and 24 h after smoke exposure. Results: Tear evaporation rate, tear lipid spread time, tear film break-up time, and vital staining scores showed significant worsening with passive smoke exposure. Tear HEL and IL-6 concentrations increased significantly 24 h after smoke exposure. Tear acrolein level showed an insignificant increase at 5 min. IC and RT-PCR revealed a significant reduction in goblet cell density, a shift toward higher squamous metaplasia grades and a significant downregulation of MUC5AC mRNA expression at 24 h. Conclusion: Even brief passive exposure to cigarette smoke in healthy non-smoker subjects was associated with adverse effects on the ocular surface health as evidenced by an increase of tear inflammatory cytokines, tear lipid peroxidation products and decrease of mucosal defense resulting in tear instability and damage to the ocular surface epithelia.     

Intrathyroidal parathyroid carcinoma: a case report with clinical and histological findings

Aims

To analyse the histo-morphology of cases of medullomyoblastoma and identifying its divergent differentiation.

Methods

A retrospective review of all cases reported as medulloblastoma between the period of Jan 2000 to Dec 2006 was carried out on Hematoxylin and eosin (H & E) stained slides. The cases were screened on light microscopy for primitive neuroectodermal component of a medulloblastoma accompanied by areas of "myoid" differentiation, identified on the basis of presence of strap cells (indicating a clear skeletal muscle differentiation) and/or large anaplastic cells with vescicular nuclei and moderate to abundant amount of eosinophilic cytoplasm. All these cases were subjected to a panel of immunohistochemical stains, including Desmin, GFAP, NFP, HMB45, SMA, S100, CK and EMA. Ultrastructral analysis was done on tissue obtained from paraffin blocks in 2 cases.

Results

Male predominance (M:F = 5:1) was noted with an incidence of five percent of all cases of medulloblastoma (6 out of 120 cases) over a period of 6 years. Primitive neuroectodermal areas were accompanied with areas of "myoid" differentiation, 5 cases showing strap cells. Two cases with epithelial and cartilaginous differentiation were seen. Three cases showed focal melanocytic differentiation, identified only on HMB45 immunostaining. Four cases showed glial differentiation. Neuronal differentiation again was very focally seen in two cases, of which one was identified only by NFP immunostain. Seventh case is included in the study, however it is not considered to calculate incidence as it occurred beyond the period of 6 years of records search.

Conclusion

Medullomyoblastoma is a rare childhood tumor of cerebellum. Majority of cases reveal divergent differentiation, which are identified with the help of panel of immunostains indicating multi-potential nature of primitive neuroectodermal cells.     

Deoxycholic acid promotes development of gastroesophageal reflux disease and Barrett's oesophagus by modulating integrin‐αv trafficking

The fundamental mechanisms underlying erosive oesophagitis and subsequent development of Barrett's oesophagus (BO) are poorly understood. Here, we investigated the contribution of specific components of the gastric refluxate on adhesion molecules involved in epithelial barrier maintenance. Cell line models of squamous epithelium (HET‐1A) and BO (QH) were used to examine the effects of bile acids on cell adhesion to extracellular matrix proteins (Collagen, laminin, vitronectin, fibronectin) and expression of integrin ligands (α₃, α_4, α₅, α₆ and α_ν). Experimental findings were validated in human explant oesophageal biopsies, a rat model of gastroesophageal reflux disease (GORD) and in patient tissue microarrays. The bile acid deoxycholic acid (DCA) specifically reduced adhesion of HET‐1A cells to vitronectin and reduced cell‐surface expression of integrin‐α_ν via effects on endocytic recycling processes. Increased expression of integrin‐α_v was observed in ulcerated tissue in a rat model of GORD and in oesophagitis and Barrett's intestinal metaplasia patient tissue compared to normal squamous epithelium. Increased expression of integrin‐α_ν was observed in QH BO cells compared to HET‐1A cells. QH cells were resistant to DCA‐mediated loss of adhesion and reduction in cell‐surface expression of integrin‐α_ν. We demonstrated that a specific component of the gastric refluxate, DCA, affects the epithelial barrier through modulation of integrin α_ν expression, providing a novel mechanism for bile acid‐mediated erosion of oesophageal squamous epithelium and promotion of BO. Strategies aimed at preventing bile acid‐mediated erosion should be considered in the clinical management of patients with GORD.     

Application of plant growth-promoting rhizobacteria to control Papaya ringspot virus and Tomato chlorotic spot virus

Papaya ringspot virus (PRSV-W) and Tomato chlorotic spot virus (TCSV) are responsible for severe losses in cucurbits and tomato production in south Florida and other regions in the USA. Traditional chemicals are not effective to control these viruses. Using plant growth-promoting rhizobacteria (PGPR) may present an alternative to control these viruses. Results from this study demonstrated that applying mixtures of PGPR strains is more efficient to control PRSV-W and TCSV compared to individual PGPR strain only. The application method significantly affected the efficiency of PGPR to control PRSV-W and TCSV. The highest reduction in disease severity of both PRSV-W and TCSV occurred in case of soil drenching with PGPR, followed by root dipping and seed coating treatments. Application of PGPR mixtures of (IN937a & SE34) or (IN937a &, SE34 & T4) were the most efficient methods to control these viral diseases.     

Integration of chitosan and plant growth-promoting rhizobacteria to control Papaya ringspot virus and Tomato chlorotic spot virus

Papaya ringspot virus-W (PRSV-W) and Tomato chlorotic spot virus (TCSV) are common viruses infecting vegetables in south Florida. Application of plant growth-promoting rhizobacteria (PGPR) has emerged as a potential alternative of chemical pesticides to control these viruses. But, it is not sufficient to completely replace chemical control. This study aimed to investigate the synergistic effect of chitosan and PGPR to control PRSV-W and TCSV. The efficiency of PGPR to suppress PRSV-W and TCSV was significantly improved when they were accompanied with chitosan treatment. The highest reduction in disease severity of both PRSV-W and TCSV was achieved when chitosan treatment was accompanied with mixture of two PGPR (IN937a + SE34) or three PGPR strains (IN937a + SE34 + SE56). The results of this study proved that implementation of chitosan and PGPR could significantly restrict losses due to PRSV-W and TCSV in squash and tomato, in Florida and the United States.     

Advances in long-term islet culture

Long-term culture of human islets provides opportunity for improving results of islet transplantation. The techniques of long-term culture are reproducible and can result in improved function of the islet after transplantation into NOD-SCID mice. We have been able to cure streptozotocin-induced diabetes by islets cultured for more than 6 mo. Culture conditions play an important role in the success of the procedure. Culture success is dependent on the media type, additives, type of colloid or protein used, purity of the islets, and concentration and volume of the tissue. Cellular and structural changes occur over time in culture. These changes may explain the improved efficacy of the islet graft after short and intermediate culture periods. Further research into long-term culture of islets is necessary to fully explore the potential of the technique.     

Antimicrobial activity of chemically and biologically synthesized silver nanoparticles against some fish pathogens

Pathogens isolated from fish appear to possess considerable antimicrobial resistance and represent a problem for the economy and public health. Natural antimicrobial substitutes to traditional antibiotics represent an essential tool in the fight against antibiotic resistance. Nanotechnology has shown considerable potential in different research fields, and the antimicrobial properties of silver nanoparticles are known. Silver has been used for medical purposes since ancient times because of its bactericidal properties, and the highly reactive surfaces of silver nanoparticles (AgNPs) indicate that they might have a function in antimicrobial applications. This work aimed to study the antimicrobial properties of biologically produced AgNPs from Origanum vulgare leaves compared to chemically produced AgNPs. Both types were characterized by UV–vis spectrophotometry, TEM, and dynamic light scattering and tested against three bacterial strains (Streptococcus agalactiae, and Aeromonas hydrophila, both isolated from Nile tilapia and Vibrio alginolyticus, isolated from sea bass) and three fungal strains (Aspergillus flavus, Fusarium moniliforme, and Candida albicans, all isolated from Nile tilapia). Disk diffusion test and evaluation of ultrastructure changes of tested microorganisms treated with AgNPs by transmission electron microscopy were performed. Moreover, the hemolytic properties of AgNPs were studied on chicken and goat red blood cells. The results obtained declare that the green biological production of silver nanoparticles is safer and more effective than the chemical one; moreover, AgNPs have interesting dose-dependent antimicrobial properties, with better results for biologically produced ones; their effectiveness against tested bacterial and fungal strains opens the way to their use to limit fish diseases, increase economy and improve human health.     

Physiological responses of wheat to drought stress and its mitigation approaches

Drought is a polygenically controlled stress and a major agricultural risk that reduces crop productivity and limits the successful insight of land potential throughout the world. This review article has been divided into two parts, i.e., effect of drought stress on physiology of wheat and potential drought mitigation approaches. In the first part, physiological responses of wheat to stress were discussed. Cell membrane stability, relative water content, early maturity, decreased leaf area, small plant size, increased dry weight and root–shoot ratio, and the whole-plant transpiration rate response to enhanced atmospheric vapor pressure deficit are physiological traits associated with drought tolerance in wheat. Reduction of relative water content closes stomata and thereby reduces stomatal conductance. Osmotic adjustment improves drought tolerance by allowing cell enlargement, plant growth, and stomata to stay partially open and by maintaining CO₂ fixation under severe water deficit. The wheat plant accumulates several organic and inorganic solutes in its cytosol to lessen its osmotic potential for maintenance of cell turgor. Drought affects photosynthesis negatively by changing the inner structure of chloroplasts, mitochondria, and chlorophyll content and minerals. Destruction of the photosystem II (PSII) oxygen releasing complex and reaction center can disturb production and use of electrons, causing lipid peroxidation of cell membrane through the production of reactive oxygen species. In the second part, drought mitigation approaches were discussed. Seed, drought, bacterial, and hormonal priming are common approaches used to lessen the effects of water deficit. Physiological trait-based breeding, molecular breeding, marker-assisted backcrossing, aerial phenotyping, water budgeting, and resource allocation are modern approaches used to develop drought tolerant wheat cultivars. Wheat genotypes produced as a result of a combination of all these methodologies will increase food security regarding the currently changing climate.     

Unveiling Chemically Robust Bimetallic Squarate-Based Metal–Organic Frameworks for Electrocatalytic Oxygen Evolution Reaction

Here, this work reports an innovative strategy for the synthesis of chemically robust metal–organic frameworks (MOFs), and applies them as catalysts for the electrocatalytic oxygen evolution reaction (OER). A bimetallic squarate-based MOF (Sq-MOF) with a zbr topology serves as an excellent platform for electrocatalytic OER owing to its open porous structure, high affinity toward water, and presence of catalytically active 1D metal hydroxide strips. By regulating the Ni²⁺ content in a bimetallic squarate MOF system, the electrochemical structural stability toward OER can be improved. The screening of various metal ratios demonstrates that Ni₃Fe₁ and Ni₂Fe₁ Sq- zbr -MOFs show the best performance for electrocatalytic OER in terms of catalytic activity and structural stability. Ni₂Fe₁ Sq- zbr -MOF shows a low overpotential of 230 mV (at 10 mA cm⁻²) and a small Tafel slope of 37.7 mV dec⁻¹, with an excellent long-term electrochemical stability for the OER. Remarkably, these overpotential values of Ni₂Fe₁ Sq- zbr -MOF are comparable with those of the best-performing layered double hydroxide (LDH) systems and outperforms the commercially available noble-metal-based RuO₂ catalyst for OER under identical operational conditions.