Morphological and physiological response of tomato (Solanum lycopersicum L.) to natural and synthetic cytokinin sources: a comparative study

Among the natural plant growth stimulants, moringa has attained enormous attention due to its leaf composition being enriched with cytokinin, antioxidants and minerals. Exogenous application of moringa leaf extract (MLE) improves productivity in many crops. This study investigated the potential of MLE with different dilutions, i.e., MLE0, MLE10, MLE20 and MLE30 (0, 10, 20 and 30 times diluted in water, respectively) to improve the performance of tomato. Foliage-applied water and benzylaminopurine (BAP, 50 mg L^?1) were taken as controls. Among treatments, foliar-applied MLE30 produced maximum vegetative and flowering branches, number of flowers and heaviest fruits per plant of tomato in comparison with synthetic BAP and other treatments. A similar increase in vegetative and flowering branches was recorded for root-applied MLE20 including BAP. Foliage-applied MLE30 also increased chlorophyll (a) pigments and leaf total soluble proteins than other stimulants used. This increase was followed by enhanced antioxidant activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), total phenolics in leaves and fruit lycopene contents of tomato. In general, foliar application of MLE30 was more effective as natural biostimulant to improve growth, productivity and fruit quality of tomato as compared to synthetic BAP and its root application.     

The endoplasmic reticulum and unfolded protein response in the control of mammalian recombinant protein production

The endoplasmic reticulum (ER) of eukaryotic cells is involved in the synthesis and processing of proteins and lipids in the secretory pathway. These processing events that proteins undergo in the ER may present major limiting steps for recombinant protein production. Increased protein synthesis, accumulation of improperly processed or mis-folded protein can induce ER stress. To cope with ER stress, the ER has quality control mechanisms, such as the unfolded protein response (UPR) and ER-associated degradation to restore homeostasis. ER stress and UPR activation trigger multiple physiological cellular changes. Here we review cellular mechanisms that cope with ER stress and illustrate how this knowledge can be applied to increase the efficiency of recombinant protein expression.     

Transgressing community: the case of Muslims in a twenty-first-century British city

Abstract

This paper draws on ethnographic research carried out in Birmingham, UK – a city significant for its sizeable Muslim population and its iconic role in the history of minority ethnic settlement in Britain – to consider how associations of place and ethnicity work in different ways to inform ideas about ‘Muslim community’ in twenty-first-century Britain. The paper charts happenings around a local event in an area of majority Asian settlement and how representations of the area as a place of Muslim community were used to implicate it in the ‘war on terror’. The paper goes on to show how this sensibility is disrupted by Muslims themselves through alternative engagements with space and ethnicity. The paper argues that these offer a ground for making Muslim community in ways that actively engage with histories and patterns of ethnic settlement in the city rather than being determined by them.     

Phosphorylation of Rab5a Protein by Protein Kinase C? Is Crucial for T-cell Migration

Rab GTPases control membrane traffic and receptor-mediated endocytosis. Within this context, Rab5a plays an important role in the spatial regulation of intracellular transport and signal transduction processes. Here, we report a previously uncharacterized role for Rab5a in the regulation of T-cell motility. We show that Rab5a physically associates with protein kinase Cϵ (PKCϵ) in migrating T-cells. After stimulation of T-cells through the integrin LFA-1 or the chemokine receptor CXCR4, Rab5a is phosphorylated on an N-terminal Thr-7 site by PKCϵ. Both Rab5a and PKCϵ dynamically interact at the centrosomal region of migrating cells, and PKCϵ-mediated phosphorylation on Thr-7 regulates Rab5a trafficking to the cell leading edge. Furthermore, we demonstrate that Rab5a Thr-7 phosphorylation is functionally necessary for Rac1 activation, actin rearrangement, and T-cell motility. We present a novel mechanism by which a PKCϵ-Rab5a-Rac1 axis regulates cytoskeleton remodeling and T-cell migration, both of which are central for the adaptive immune response.     

Tsc2 Is a Molecular Checkpoint Controlling Osteoblast Development and Glucose Homeostasis

Insulin signaling in osteoblasts regulates global energy balance by stimulating the production of osteocalcin, a bone-derived protein that promotes insulin production and action. To identify the signaling pathways in osteoblasts that mediate insulin''s effects on bone and energy metabolism, we examined the function of the tuberous sclerosis 2 (Tsc2) protein, a key target important in coordinating nutrient signaling. Here, we show that loss of Tsc2 in osteoblasts constitutively activates mTOR and destabilizes Irs1, causing osteoblasts to differentiate poorly and become resistant to insulin. Young Tsc2 mutant mice demonstrate hypoglycemia with increased levels of insulin and undercarboxylated osteocalcin. However, with age, Tsc2 mutants develop metabolic features similar to mice lacking the insulin receptor in the osteoblast, including peripheral adiposity, hyperglycemia, and decreased pancreatic β cell mass. These metabolic abnormalities appear to result from chronic elevations in undercarboxylated osteocalcin that lead to downregulation of the osteocalcin receptor and desensitization of the β cell to this hormone. Removal of a single mTOR allele from the Tsc2 mutant mice largely normalizes the bone and metabolic abnormalities. Together, these findings suggest that Tsc2 serves as a key checkpoint in the osteoblast that is required for proper insulin signaling and acts to ensure normal bone acquisition and energy homeostasis.     

Molecular insights into the association of obesity with breast cancer risk: relevance to xenobiotic metabolism and CpG island methylation of tumor suppressor genes

Obesity, genetic polymorphisms of xenobiotic metabolic pathway, hypermethylation of tumor suppressor genes, and hypomethylation of proapoptotic genes are known to be independent risk factors for breast cancer. The objective of this study is to evaluate the combined effect of these environmental, genetic, and epigenetic risk factors on the susceptibility to breast cancer. PCR–RFLP and multiplex PCR were used for the genetic analysis of six variants of xenobiotic metabolic pathway. Methylation-specific PCR was used for the epigenetic analysis of four genetic loci. Multifactor dimensionality reduction analysis revealed a significant interaction between the body mass index (BMI) and catechol-O-methyl transferase H108L variant alone or in combination with cytochrome P450 (CYP) 1A1m1 variant. Women with “Luminal A” breast cancer phenotype had higher BMI compared to other phenotypes and healthy controls. There was no association between the BMI and tumor grade. The post-menopausal obese women exhibited lower glutathione levels. BMI showed a positive association with the methylation of extracellular superoxide dismutase (r = 0.21, p < 0.05), Ras-association (RalGDS/AF-6) domain family member 1 (RASSF1A) (r = 0.31, p < 0.001), and breast cancer type 1 susceptibility protein (r = 0.19, p < 0.05); and inverse association with methylation of BNIP3 (r = ?0.48, p < 0.0001). To conclude based on these results, obesity increases the breast cancer susceptibility by two possible mechanisms: (i) by interacting with xenobiotic genetic polymorphisms in inducing increased oxidative DNA damage and (ii) by altering the methylome of several tumor suppressor genes.     

Uptake and cellular distribution,in four plant species,of fluorescently labeled mesoporous silica nanoparticles

Key message

We report the uptake of MSNs into the roots and their movement to the aerial parts of four plant species and their quantification using fluorescence, TEM and proton-induced x - ray emission (micro - PIXE) elemental analysis.

Abstract

Monodispersed mesoporous silica nanoparticles (MSNs) of optimal size and configuration were synthesized for uptake by plant organs, tissues and cells. These monodispersed nanoparticles have a size of 20 nm with interconnected pores with an approximate diameter of 2.58 nm. There were no negative effects of MSNs on seed germination or when transported to different organs of the four plant species tested in this study. Most importantly, for the first time, a combination of confocal laser scanning microscopy, transmission electron microscopy and proton-induced X-ray emission (micro-PIXE) elemental analysis allowed the location and quantification MSNs in tissues and in cellular and sub-cellular locations. Our results show that MSNs penetrated into the roots via symplastic and apoplastic pathways and then via the conducting tissues of the xylem to the aerial parts of the plants including the stems and leaves. The translocation and widescale distribution of MSNs in plants will enable them to be used as a new delivery means for the transport of different sized biomolecules into plants.     

Bacterial endophyte Sphingomonas sp. LK11 produces gibberellins and IAA and promotes tomato plant growth

Plant growth promoting endophytic bacteria have been identified as potential growth regulators of crops. Endophytic bacterium, Sphingomonas sp. LK11, was isolated from the leaves of Tephrosia apollinea. The pure culture of Sphingomonas sp. LK11 was subjected to advance chromatographic and spectroscopic techniques to extract and isolate gibberellins (GAs). Deuterated standards of [17, 17-²H₂]-GA₄, [17, 17-²H₂]-GA₉ and [17, 17-²H₂]-GA₂₀ were used to quantify the bacterial GAs. The analysis of the culture broth of Sphingomonas sp. LK11 revealed the existence of physiologically active gibberellins (GA₄: 2.97 ± 0.11 ng/ml) and inactive GA₉ (0.98 ± 0.15 ng/ml) and GA₂₀ (2.41 ± 0.23). The endophyte also produced indole acetic acid (11.23 ± 0.93 μM/ml). Tomato plants inoculated with endophytic Sphingomonas sp. LK11 showed significantly increased growth attributes (shoot length, chlorophyll contents, shoot, and root dry weights) compared to the control. This indicated that such phyto-hormones-producing strains could help in increasing crop growth.     

A quantitative Real Time PCR based method for the detection of Phytophthora infestans causing Late blight of potato,in infested soil

A fast and simple polymerase chain reaction method has been developed for detection of Phytophthora infestans oospores, the causal agent of Late blight of Potato in soil. The method involves the disruption of oospores by grinding dry soil, using abrasive properties, in the presence of glass powder and skimmed milk powder within a short time. The latter prevents loss of DNA by adsorption to soil particles or by degradation and reduces the co-extraction of PCR inhibitors with the DNA. After phenol/chloroform extraction; the DNA is suitable for direct PCR amplification without a precipitation step. This amplification leads to detection of pathogen in infested soils before planting of crop. The real-time PCR assay we describe is highly sensitive and specific, and has several advantages over conventional PCR assays used for P. infestans detection to confirm positive inoculum level in potato seeds and elsewhere. With increasing amounts of standard DNA templates, the respective threshold cycle (Ct) values were determined and a linear relationship was established between these Ct values and the logarithm of initial template amounts. The method is rapid, cost efficient, and when combined with suitable internal controls can be applied to the detection and quantification of P. infestans oospores on a large-scale basis.