Effects of gibberellic acid and prohexadione-calcium on growth,chlorophyll fluorescence and quality of okra plant

The experiment was conducted to identify the response of three cultivars of okra [Abelmoschus esculentus (L.) Moench] to exogenous hormones [gibberellic acid-(GA₃) and prohexadione-Ca] applied as foliar spray. Stem and leaf dry masses and stem length were significantly enhanced by the application of exogenous GA₃, but prohexadione-Ca inhibited growth. Control and prohexadione-Ca treated okra plants took more time to bloom than did GA₃ treated plants. In the fruits of all the cultivars a decrease in fructose content was observed, while protein content remained almost unchanged after the application of the two growth regulators. The small changes in chlorophyll a fluorescence characteristics observed under prohexadione-Ca suggested a weakening of the photochemical processes near the photosystem 2 reaction centre. The lowering of ratio between maximum time to reach maximum fluorescence, F_m (T_max) and Area (sum of F_m-F_t for t = 0 to t = T_max) caused by GA₃ was probably due to the increase of Area rather than to changes in T_max.     

Potential antidiabetic activity and molecular docking studies of novel synthesized 3.6-dimethyl-5-oxo-pyrido[3,4-f][1,2,4]triazepino[2,3-a]benzimidazole and 10-amino-2-methyl-4-oxo pyrimido[1,2-a]benzimidazole derivatives

Diabetes affects a large population of the globe and is considered as a leading cause of death. Many synthetic and natural inhibitors have been developed for diabetes treatment. Herein, we report the potential antidiabetic activity of two new heterocyclic systems, namely 3.6-dimethyl-5-oxo-pyrido[3,4f][1,2,4]triazepino[2,3-a]benzimidazole (I) and 10-amino-2-methyl-4-oxo pyrimido[1,2-a]benzimidazole (II) against three related enzymes: α-amylase, α-glucosidase and β-galactosidase. Compounds I and II were synthesized by the action of DMF-DMA and dimethyl sulfate in the presence of water on 2-methyl-3H-benzimidazolo[1,2b][1,2,4]triazepin-4(5H)-one, and are characterized by single X-ray diffraction. The binding interaction modes in the active sites of I and II and targeted enzymes (stable complexes ligand-receptor) are emphasized using the molecular docking approach by applying the Lamarckian genetic algorithm method. Furthermore, plausible mechanisms have been proposed explaining their synthesis. Hirshfeld surface analysis reveals the nature of molecular interactions and fingerprint plots provide information about the percentage contribution from each individual molecular contact to the structure surface.

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Graphical abstract Left Molecular packing of 1,4-dimethyl-2-oxo-pyrimido[1,2-a]benzimidazole hydrate. Right Docking active site of α-glucosidase

     

Tectonic epikeratoplasty with ethanol-stored donor corneas

To evaluate the efficacy and outcomes of tectonic epikeratoplasty with use of ethanol-preserved corneal grafts for the management of perforated corneal melts. The present retrospective case series includes 10 eyes which underwent tectonic epikeratoplasty for perforated corneal melts. The stromal remainders of Descemet membrane endothelial keratoplasty (DMEK) and Descemet stripping automated endothelial keratoplasty (DSAEK) graft preparation were stored in 95% ethanol and used as emergency tectonic grafts for restoring globe integrity after sterile and infectious perforated corneal melts. In 6 cases with subtotal corneal melt, DMEK remainders (endothelium-denuded corneoscleral buttons) were used for ‘limbus to limbus’ tectonic epikeratoplasty and in 4 cases DSAEK remainders (anterior stroma) were used to seal focal perforated melts. Graft storage time was 5.1?±?4.9 (ranging from 0.5 to 17) months. The surgeries were successful in all cases with restitution of the globe integrity. During the postoperative course 4 cases developed a graft melt (corneoscleral button for limbus to limbus tectonic epikeratoplasty, n?=?3; lamellar patch, n?=?1) within 2–6 months after the initial procedure. Three patients underwent successful repeat tectonic epikeratoplasty. In the fourth case of graft melt the globe was enucleated due to underlying expulsive haemorrhage and severe pain. The short-term results of the present case series suggest that the use of ethanol-stored stromal remainder of donor corneas after endothelial keratoplasty is an efficient temporary measure for tectonic restoration of perforated corneas.     

An analysis of class I antigens of man and other species by one-dimensional IEF and immunoblotting

A procedure for the molecular identification of MHC class I products based on 1-D IEF and subsequent immunoblotting is described. Optimal conditions for 1-D IEF, the electrophoretic transfer of proteins out of denaturing, nonionic detergent-containing gels to nitrocellulose, and the requisite antibodies, both polyclonal and monoclonal, for the visualization of class I heavy chains have been established. Cross-reactivity of antibodies has enabled the biochemical analysis of class I heavy chains in the dog. The procedure reported here requires modest amounts of cells and allows a rapid molecular characterization of class I heavy chain polymorphisms in man and other species without the need for radiochemical methods.Abbreviations used in this paper FCS fetal calf serum - MHC major histocompatibility complex - NP-40 Nonidet P-40 - PBL peripheral blood lymphocytes - PHA phytohemagglutinin - RaHC rabbit anti-heavy chain serum - TX-114 Triton X-114 - 1-D IEF one-dimensional isoelectric focusing     

Herbivory in global climate change research: direct effects of rising temperature on insect herbivores

This review examines the direct effects of climate change on insect herbivores. Temperature is identified as the dominant abiotic factor directly affecting herbivorous insects. There is little evidence of any direct effects of CO₂ or UVB. Direct impacts of precipitation have been largely neglected in current research on climate change. Temperature directly affects development, survival, range and abundance. Species with a large geographical range will tend to be less affected. The main effect of temperature in temperate regions is to influence winter survival; at more northerly latitudes, higher temperatures extend the summer season, increasing the available thermal budget for growth and reproduction. Photoperiod is the dominant cue for the seasonal synchrony of temperate insects, but their thermal requirements may differ at different times of year. Interactions between photoperiod and temperature determine phenology; the two factors do not necessarily operate in tandem. Insect herbivores show a number of distinct life‐history strategies to exploit plants with different growth forms and strategies, which will be differentially affected by climate warming. There are still many challenges facing biologists in predicting and monitoring the impacts of climate change. Future research needs to consider insect herbivore phenotypic and genotypic flexibility, their responses to global change parameters operating in concert, and awareness that some patterns may only become apparent in the longer term.     

Diagnosis and management of tumors of the adrenal medulla.

The adrenal medulla consists of chromaffin cells, the site of catecholamine biosynthesis. Pheochromocytomas are chromaffin-cell tumors; 80-85 % arise from the adrenal medulla and 15-20 % arise from extra-adrenal chromaffin tissues (paragangliomas). Neuroblastomas are primitive tumors that derive from the same blastic precursor as in pheochromocytomas, and are distributed along the sympathetic nervous system. Pheochromocytomas account for 6.5 % of incidentally discovered adrenal tumors; they are found in 50 % of patients with multiple endocrine neoplasia 2A (MEN 2A) and 5-25 % of patients with von Hippel-Lindau (VHL) syndrome. Neuroblastomas are the most common solid extra-cranial tumors in children, and account for 7-10 % of all tumors. The diagnosis of pheochromocytoma should first be established biochemically by measuring plasma free metanephrines (the measurement of urinary fractionated metanephrines is the second choice). Measurements of homovanillic acid (HVA), norepinephrine and vanilmandelic acid (VMA) in urine are a necessity in patients with suspected neuroblastoma. Anatomical (radiological) imaging with computed tomography (CT) or magnetic resonance imaging (MRI) is necessary for both pheochromocytomas and neuroblastomas. Functional (nuclear medicine) methods are useful for both tumors. Scintigraphy with [123I]-metaiodobenzylguanidine is the specific functional imaging test of first choice; if this is not available, scintigraphy with [131I]-MIBG is the second choice. Other newer specific modalities that have been used for evaluating pheochromocytomas include positron emission tomography (PET) with [18F]-F-fluorodopamine (F-DA) and [18F]-F-dihydroxyphenylalanine (DOPA). These should be used when MIBG scintigraphy is negative. Primary treatment for both types of tumor is surgical; chemotherapy is used for inoperable disease. After successful surgery, survival of patients with benign, sporadic pheochromocytomas is believed to be equal to that of the general population. Depending on the extent of disease and age, patients with neuroblastomas have cure rates of 15-90 %.     

The "open" and "closed" structures of the type-C inorganic pyrophosphatases from Bacillus subtilis and Streptococcus gordonii.

Recently, a new class of soluble inorganic pyrophosphatase (type-C PPase) has been described that is not homologous in amino acid sequence or kinetic properties to the well-studied PPases (types A and B) found in many organisms from bacteria to humans and thought to be essential to the cell. Structural studies of the type-C PPases from Streptococcus gordonii and Bacillus subtilis reveal a homodimeric structure, with each polypeptide folding into two domains joined by a flexible hinge. The active site, formed at the interface between the N and C-terminal domains, binds two manganese ions approximately 3.6 A apart in a conformation resembling binuclear metal centres found in other hydrolytic enzymes. An activated water molecule bridging the two metal ions is likely poised for nucleophilic attack of the substrate. Importantly, the S. gordonii and B. subtilis enzymes have crystallised in strikingly different conformations. In both subunits of the S. gordonii crystal structure (1.5 A resolution) the C-terminal domain is positioned such that the active site is occluded, with a sulphate ion bound in the active site. In contrast, in the B. subtilis structure (3.0 A resolution) the C-terminal domain is rotated by about 90 degrees, leaving the active site wide open and accessible for substrate binding.     

The dietary flavonoid kaempferol effectively inhibits HIF-1 activity and hepatoma cancer cell viability under hypoxic conditions

Hepatocellular carcinoma (HCC) is characterized by high mortality rates and resistance to conventional treatment. HCC tumors usually develop local hypoxia, which stimulates proliferation of cancer cells and renders them resilient to chemotherapy. Adaptation of tumor cells to the hypoxic conditions depends on the hypoxia-inducible factor 1 (HIF-1). Over-expression of its regulated HIF-1α subunit, an important target of anti-cancer therapy, is observed in many cancers including HCC and is associated with severity of tumor growth and poor patient prognosis. In this report we investigate the effect of the dietary flavonoid kaempferol on activity, expression levels and localization of HIF-1α as well as viability of human hepatoma (Huh7) cancer cells. Treatment of Huh7 cells with kaempferol under hypoxic conditions (1% oxygen) effectively inhibited HIF-1 activity in a dose-dependent manner (IC₅₀ = 5.16 μM). The mechanism of this inhibition did not involve suppression of HIF-1α protein levels but rather its mislocalization into the cytoplasm due to inactivation of p44/42 MAPK by kaempferol (IC₅₀ = 4.75 μM). Exposure of Huh7 cells to 10 μΜ kaempferol caused significant reduction of their viability, which was remarkably more evident under hypoxic conditions. In conclusion, kaempferol, a non-toxic natural food component, inhibits both MAPK and HIF-1 activity at physiologically relevant concentrations (5-10 μM) and suppresses hepatocarcinoma cell survival more efficiently under hypoxia. It has, therefore, potential as a therapeutic or chemopreventive anti-HCC agent.