The contributions of nitrogen-fixing crop legumes to the productivity of agricultural systems

Data collated from around the world indicate that, for every tonne of shoot dry matter produced by crop legumes, the symbiotic relationship with rhizobia is responsible for fixing, on average on a whole plant basis (shoots and nodulated roots), the equivalent of 30–40 kg of nitrogen (N). Consequently, factors that directly influence legume growth (e.g. water and nutrient availability, disease incidence and pests) tend to be the main determinants of the amounts of N₂ fixed. However, practices that either limit the presence of effective rhizobia in the soil (no inoculation, poor inoculant quality), increase soil concentrations of nitrate (excessive tillage, extended fallows, fertilizer N), or enhance competition for soil mineral N (intercropping legumes with cereals) can also be critical. Much of the N₂ fixed by the legume is usually removed at harvest in high-protein seed so that the net residual contributions of fixed N to agricultural soils after the harvest of legumegrain may be relatively small.Nonetheless, the inclusion of legumes in a cropping sequence generally improves the productivity of following crops. Whilesome of these rotational effects may be associated with improvements in availability of N in soils, factors unrelated to N also play an important role. Recent results suggest that one such non-N benefit may be due to the impact on soil biology of hydrogenemitted from nodules as a by-product of N₂, fixation.     

Enhancement of osteoblast biocompatibility on titanium surface with Terrein treatment

Titanium is biocompatible with bodily tissues. However, the formation of ROS on the titanium surfaces might have negative response of the activity of the surroundings cells. Terrein was isolated from Penicullium sp. 20135 and found to reduce the effects of LPS-induced inflammation. This study examined the role of Terrein on the biocompatibility of titanium to determine if it can help improve osseointegration. MC-3T3 E1 cells were grown on titanium surfaces. The biocompatibility of Terrein was examined by adding it directly to the culture media at the indicated concentration. The cells on the titanium surface produced excessive ROS and decreased the activity of Cu/Zn SOD and Mn SOD. Moreover, the cells had higher activity towards oxidative stress molecules, such as MAPK, FAK and iNOS expression. In addition, MC-3T3 E1 osteoblast-like cells promoted osteoclast differentiation but reduced osteoblast differentiation and mineralization on the titanium surface. Interestingly, the cells given the Terrein treatment showed higher resistance towards oxidative stress through the up-regulation of ERK1/2 and FAK activity but the down-regulation of SAPK/JNK and iNOS activity. Moreover, Terrein promoted osteoblast differentiation and bone mineralization to elevate the activity of ALP, SPARC and down-regulate RANKL expression after blocking NF-κB translocation from the cytosol to the nucleus. In conclusion, the presence of Terrein on titanium surfaces increases osteoblast cell growth without inflammation. Moreover, Terrein, as a putative antioxidant agent, may enhance osseointegration by decreasing the level of ROS and having a potentially synergistic effect on osteoblast differentiation.     

Binding, electrochemical activation, and cleavage of DNA by cobalt(II) tetrakis-N-methylpyridyl porphyrin and its beta-pyrrole brominated derivative

The binding of nucleic acids by water-soluble cobalt(II) tetrakis-N-methylpyridyl porphyrin, (TMPyP)Co, and its highly electron-deficient derivative cobalt(II) tetrakis-N-methyl pyridyl-beta-octabromoporphyrin, (Br(8)TMPyP)Co, was investigated by UV-visible absorption, circular dichroism (CD), and electrochemical and gel electrophoresis methods. The changes of the absorption spectra during the titration of these complexes with polynucleotides revealed a shift in the absorption maxima and a hypochromicity of the porphyrin Soret bands. The intrinsic binding constants were found to be in the range of 10(5)-10(6) M(-1). These values were higher for the more electron-deficient (Br(8)TMPyP)Co. Induced CD bands were noticed in the Soret region of the complexes due to the interaction of these complexes with different polynucleotides, and an analysis of the CD spectra supported a mainly external mode of binding. Electrochemical studies revealed the cleavage of polynucleotides by (TMPyP)Co and (Br(8)TMPyP)Co in the presence of oxygen preferentially at the A-T base pair region. Gel electrophoresis experiments further supported the cleavage of nucleic acids. The results indicate that the beta-pyrrole brominated porphyrin, (Br(8)TMPyP)Co, binds strongly and cleaves nucleic acids efficiently as compared with (TMPyP)Co. This electrolytic procedure offers a unique tool in biotechnology for cleaving double-stranded DNA with specificity at the A-T regions.     

Inhibition of IKK-β: A new development in the mechanism of the anti-obesity effects of PTP1B inhibitors SA18 and SA32

In a previous study, protein tyrosine phosphatase 1B (PTP1B) inhibitors, SA18 and SA32, exhibited anti-obesity effects in a mouse model by suppressing weight gain and improving blood parameters, including free fatty acid (FFA) levels. In a separate study, depletion of the PTP1B gene in mice suppressed weight gain without significant change in FFA levels. The discrepancy in FFA concentrations between the two studies suggested that the in vivo target of the SA compounds might not be limited to PTP1B. In this study, SA18 and SA32 were found to be potent inhibitors of IκB Kinase-β (IKK-β). In vivo relevance of the inhibitory activity was evaluated in differentiated adipocytes. Inhibition of IKK-β, in addition to inhibition of PTP1B, in mice treated with the SA compounds, could be a possible mechanism of the compound’s biological response including the resistance to diet-induced weight gain and improvement in blood parameters. As potent and cell-permeable IKK-β inhibitors, SA18 and SA32 could also be valuable in biological experiments.     

Nitric oxide and hydrogen sulfide crosstalk during heavy metal stress in plants

Gases such as ethylene, hydrogen peroxide (H₂O₂), nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H₂S) have been recognized as vital signaling molecules in plants and animals. Of these gasotransmitters, NO and H₂S have recently gained momentum mainly because of their involvement in numerous cellular processes. It is therefore important to study their various attributes including their biosynthetic and signaling pathways. The present review provides an insight into various routes for the biosynthesis of NO and H₂S as well as their signaling role in plant cells under different conditions, more particularly under heavy metal stress. Their beneficial roles in the plant's protection against abiotic and biotic stresses as well as their adverse effects have been addressed. This review describes how H₂S and NO, being very small-sized molecules, can quickly pass through the cell membranes and trigger a multitude of responses to various factors, notably to various stress conditions such as drought, heat, osmotic, heavy metal and multiple biotic stresses. The versatile interactions between H₂S and NO involved in the different molecular pathways have been discussed. In addition to the signaling role of H₂S and NO, their direct role in posttranslational modifications is also considered. The information provided here will be helpful to better understand the multifaceted roles of H₂S and NO in plants, particularly under stress conditions.     

Synthesis of 6‐[4‐(4‐Propoxyphenyl)piperazin‐1‐yl]‐9H‐purine Derivatives as Antimycobacterial and Antifungal Agents: In Vitro Evaluation and In Silico Study

A series of novel alkyl substituted purines were synthesized. 6‐[4‐(4‐Propoxyphenyl)piperazin‐1‐yl]‐9H‐purine was used as the key starting material, which was synthesized via a multistep protocol and finally subjected for N‐alkylation with various alkyl halides with an aim to get prospective antimicrobial agents. The structures of the novel compounds were established by substantiating them through spectral techniques like ¹H‐NMR, ¹³C‐NMR, FT‐IR and EI‐MS. They were explored for antitubercular activity against Mycobacterium tuberculosis H37RV. Furthermore, they were checked for their antimicrobial activity concerning bacterial and fungal strains. The title compounds exhibited considerable antimicrobial activity without any significant toxicity. In silico studies depicted their good binding profile against Mycobacterium tuberculosis enoyl reductase (InhA; PDB ID: 4TZK) and Candida albicans dihydrofolate reductase (PDB ID: 1AI9). The title compounds obeyed Lipinski's parameters and have exhibited good drug‐like properties.     

Dietary daidzein decreases food intake accompanied with delayed gastric emptying in ovariectomized rats

ABSTRACT

We previously found that equol, a metabolite of intestinal bacterial conversion from soy isoflavone daidzein, has female-specific anorectic effects. In the present study, we used seven-week-old female ovariectomized (OVX) Sprague Dawley rats to test the hypothesis that the anorectic effect of dietary daidzein may be attributed to delayed gastric emptying. Results suggest that dietary daidzein delays gastric emptying and that it has an anorectic effect with residual gastric contents, but not without gastric contents. Dietary equol significantly decreased daily food intake in the OVX rats without sleeve gastrectomy, but not in those with sleeve gastrectomy, suggesting that the accumulation of food in the stomach is required for the anorectic effect of equol to occur. These results support the hypothesis that the anorectic effect of dietary daidzein is attributed to delayed gastric emptying.     

Homology modeling and docking studies of Streptomyces peucetius CYP147F1 as limonene hydroxylase

Homology modeling of Streptomyces peucetius CYP147F1 was constructed using three cytochrome P450 structures, CYP107L1, CYPVdh, and CYPeryF, as templates. The lowest energy SPCYP147F1 model was then assessed for stereochemical quality and side-chain environment by Accelrys Discovery Studio 3.1 software. Further activesite optimization of the SPCYP147F1 was performed by molecular dynamics to generate the final SPCYP147F1 model. The substrate limonene was then docked into the model. The model-limonene complex was used to validate the active-site architecture, and functionally important residues within the substrate recognition site were identified by subsequent characterization of the secondary structure. The docking of limonene suggested that SPCYP147F1 would have broad specificity with the ligand based on the two different orientations of limonene within the active site facing to the heme. Limonene with C7 facing the heme with distance of 3.4 Angstrom from the Fe was predominant.     

RNA Interference-Based Therapy for Spinocerebellar Ataxia Type 7 Retinal Degeneration

Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant neurodegenerative disease characterized by loss of motor coordination and retinal degeneration with no current therapies in the clinic. The causative mutation is an expanded CAG repeat in the ataxin-7 gene whose mutant protein product causes cerebellar and brainstem degeneration and retinal cone-rod dystrophy. Here, we reduced the expression of both mutant and wildtype ataxin-7 in the SCA7 mouse retina by RNA interference and evaluated retinal function 23 weeks post injection. We observed a preservation of normal retinal function and no adverse toxicity with ≥50% reduction of mutant and wildtype ataxin-7 alleles. These studies address an important safety concern regarding non-allele specific silencing of ataxin-7 for SCA7 retinal therapy.     

Impact of oxygation on soil respiration,yield and water use efficiency of three crop species

Aims Oxygation refers to irrigation of crops with aerated water, through air injection using the venturi principle or the supply of hydrogen peroxide in the root zone, both using subsurface drip irrigation (SDI) system. Oxygation improves water use efficiency (WUE), producing more yield and, and therefore, optimizes the use of drip and SDI. But the efficiency of oxygation is quite possibly dependent on a number of factors. The primary objective of this study was, therefore, to quantify the effects of oxygation, emitter depths and soil type on crop root zone oxygen content, soil respiration, plant physiological response, biomass yield, quality and WUE of three crop species.Methods This study investigated the potential of oxygation to enhance soil respiration, plant growth, yield and water use efficiencies (WUE) of cotton and wheat in experiments in enclosed heavy-duty concrete troughs (tubs) and pineapple and cotton in field experiments. Experimental treatments in tubs for wheat included comparisons between two soil types (vertisol and ferrosol) and superimposed were two oxygation methods (Mazzei air injector and Seair Diffusion System) compared to a control, and for cotton, emitters at two depths using Mazzei air injectors were compared to a control. The field experiments compared Mazzei air injectors and a control for cotton in Emerald and pineapple in Yeppoon, both in central Queensland, Australia.Important findings In all experiments, soil oxygen content and soil respiration markedly increased in response to the oxygation treatments. The O 2 concentration in the crop root zone increased by 2.4–32.6%, for oxygation compared to control at the same depth. The soil respiration increased by 42–100%. The number of wheat ears, leaf dry weight and total dry matter were significantly greater in Mazzei and Seair oxygation compared to the control. Fresh biomass of wheat increased by 11 and 8%, and dry weight of wheat increased by 8 and 3% in Mazzei and Seair oxygation treatments compared to the control, respectively. Likewise, the irrigation water use efficiency increased with oxygation compared to the control in wheat. The yield, WUE and number of other physiological parameters in wheat were enhanced in vertisol compared to ferrosol. The seed cotton yield in the tub experiment increased with oxygation by 14%, and significant differences for fresh biomass, dry matter and yield were also noted between oxygation and the control in the field. Lint yield and WUE both increased by 7% using Mazzei in the cotton field trial during 2008–09. There were significant effects of oxygation on pineapple fresh biomass, and dry matter weight, industry yield and a number of quality parameters were significantly improved. The total fruit yield and marketable increased by 17 and 4% and marketable WUE increased by 3% using Mazzei. Our data suggest that the benefits of oxygation are notable not only for dicotyledonous cotton but also for monocotyledonous wheat and pineapple representing different rooting morphologies and CO₂ fixation pathways.