Ingenol esters from the pro-inflammatory fraction of Euphorbia kamerunica

A series of unstable mono- and di-esters of the tetracyclic diterpene ingenol were isolated from the pro-inflammatory ether-soluble fraction of the latex of Euphorbia kamerunica. The esters were isolated by a neutral process involving column and thin-layer chromatography. The monoesters were identified by spectroscopic methods and hydrolysis reactions as ingenol-3-decanoate, ingenol-3-dodecanoate, ingenol-5-hexadienoate and ingenol-5-octenoate and the diesters as 20-acetyl-ingenol-3-octenoate and 20-acetyl-ingenol-3-angelate.     

Further characterization of the autologous mixed lymphocyte reaction: induction of double negative gamma delta T lymphocytes.

To investigate the specific nature of the autologous mixed lymphocyte reaction (AMLR), we applied a method in which mixtures of NY-nonadherent responder cells and NY-adherent stimulator cells were treated with neuraminidase before culture and then cultured to assay the AMLR. This method produced a marked enhancement of DNA replication in the responder cells and the results were reproducible, regardless of the individuals tested. Using this method, we were able to make the following observations regarding the specific nature of the AMLR. (i) The AMLR is an IL-2-independent reaction, as revealed by bioassay to detect the presence of IL-2 by a blocking test using anti-IL-2R sera and as shown by the absence of mRNA for IL-2 in Northern hybridization. (ii) It is also HLA-DR dependent as proven by the fact that anti-DR sera almost completely inhibited the reaction. (iii) The AMLR was also found to induce the generation of activated CD4+ helper T cells in direct response to stimulation by NY-adherent cells, in which HLA-DR antigens were involved. (iv) Also, it induced the generation of CD4-CD8- double-negative (DN) lymphocytes, including gamma delta T cells with a cytotoxic activity against NK-resistant target cells and with a variety of lymphocyte activation markers (CD56, HLA-DR, CD25, transferrin receptors, CD38, and LFA-1). However, the AMLR did not induce the generation of NK cell markers CD16 and CD57. (v) The DN lymphocytes and gamma delta T cells appeared to be generated from the precursors of CD4-CD8- DN cells, in direct response to the stimulator cells. These results strongly suggest that the AMLR may be a phenomenon which induces the proliferative response of gamma delta T cells and their precursors, in addition to that of alpha beta T cells, particularly of CD4+ helper T cells.     

Studies of surface immunoglobulins on human B lymphocytes. I. Dissociation of cell-bound immunoglobulins with acid pH or at 37 degrees C.

Lymphocyte preparations isolated from the human peripheral blood were exposed to different acid pH or incubated at 37 degrees C and the presence of immunoglobulin (Ig) on the cell surface was examined by immunofluorescence (IF) tests. Subsequently, such treated cells were incubated in the autologous serum or in the purified IgG, IgA or IgM proteins and their ability to bind each class of Ig was examined. The results showed that IgG molecules dissociated from large proportions of IgG-positive cells upon exposure to pH 4 at 1 degrees C for 1 min or upon incubation at 37 degrees C for 20 min. The cells from which IgG had been dissociated could again combine with IgG, whereupon the number of positive cells increased, being restored to the number of equivalent to or higher than those before acid or 37 degrees C treatment. These results indicated that the treatment could elute the cell-bound IgG present on the cell and that the receptor sites were not degraded by the treatment and could combine with IgG. These cell-bound IgG were observed not only on the monocytes, but also on the small lymphocytes. It was also found that certain proportions of mononuclear cells carried the cell-bound IgA that could be dissociated with acid pH or 37 degrees C. No cell-bound IgM was observed on any mononuclear cells. Microscopic observations before and after acid or 37 degrees C treatment revealed that the staining distribution of the cell-bound IgG and IgA on the cell was granular, appearing as a discontinuous fluorescence ring and forming multiple aggregates but no typical polar caps on warming. In contrast, IgG, IgA, and IgM stable to acid or 37 degrees C treatment were found on the lymphocytes but not on the monocytes, and their staining distribution was uniformaly diffuse, appearing as a continuous ring and forming a typical cap on warming. Exposure of the cells to pH 4 or 37 degrees C could also elute the cell-bound IgG passively adsorbed to the human lymphoid cells in a culture, but did not affect the intrinsic S.Ig on the lymphoid cells in a culture or on the lymphoma cells. These results indicate that the exposure of the cells to acid pH or to 37 degrees C may enable us to detect unfailingly S.Ig lymphocytes by removing the cell-bound IgG and IgA present on the monocytes and/or lymphocytes. Thus, an average value of approximately 10% was obtained for the S.Ig lymphocyte in the lymphocyte preparations from 11 healthy individuals. In addition, the results provided the evidence that, even in normal peripheral blood lymphocytes, there may be a population of B lymphocytes which lack the S.Ig but carry the cell-bound Ig.     

Exogenous application of spermine and putrescine mitigate adversities of drought stress in wheat by protecting membranes and chloroplast ultra-structure

Polyamines (PAs) are positively charged molecules known to mitigate drought stress; however, little is known about their mechanism of alleviating drought stress. We investigated the effects of PAs exogenously applied as a seed primer and as a foliar spray on the growth, membrane stability (MS), electrolyte leakage (EL), Na+ and K+ cations, reactive oxygen species (ROS), catalase (CAT; EC 1.11.1.6) and guaiacol peroxidase (GPX; EC 1.11.1.7) activity and chloroplast ultra-structure in wheat (Triticum aestivum L.; cv. Sakha-94) under drought stress. Three PA solutions, namely, putrescine, spermine and a mixture of the two (Mix), were each applied at a concentration of 100 µM. Our study demonstrated that the retardation of chlorophyll loss and elevation of Rubisco levels were involved in PA-enhanced growth under drought stress. These relationships were mainly reflected in elevated fresh weight and dry weight in response to foliar spraying with all PA solutions and seed priming with the Mix solution. The elevated growth seemed to be due to increased photosynthetic pigments, protein and Rubisco. In contrast, drought decreased growth, photosynthetic pigments, protein and Rubisco. MS was enhanced by PAs applied as a seed primer or foliar spray, as shown by clear reductions in EL %, malondialdehyde (MDA) content and the Na+/K+ ratio as well as reduced ROS markers and elevated CAT (but not GPX) activity. Further study showed that the Mix solution of PAs, applied either during seed priming or as a foliar spray, improved chloroplast ultra-structure, suggesting that improvements in Rubisco and photosynthetic pigments were involved in PA maintenance of chloroplast stability. Therefore, the present study showed that elevated CAT activity is the main mechanism through which PAs reduce ROS and MDA, thereby improving MS and protecting mesophyll cells structurally and functionally under drought stress in wheat.     

Catalpol synergistically potentiates the anti-tumour effects of regorafenib against hepatocellular carcinoma via dual inhibition of PI3K/Akt/mTOR/NF-κB and VEGF/VEGFR2 signaling pathways

Molecular Biology Reports - Hepatocellular carcinoma (HCC) is the most common primary liver cancer characterized by dysregulation of several crucial cellular signaling pathways such as...     

Exploring the role of microRNAs in axolotl regeneration

The axolotl, Ambystoma mexicanum, is used extensively for research in developmental biology, particularly for its ability to regenerate and restore lost organs, including in the nervous system, to full functionality. Regeneration in mammals typically depends on the healing process and scar formation with limited replacement of lost tissue. Other organisms, such as spiny mice (Acomys cahirinus), salamanders, and zebrafish, are able to regenerate some damaged body components. Blastema is a tissue that is formed after tissue injury in such organisms and is composed of progenitor cells or dedifferentiated cells that differentiate into various cell types during regeneration. Thus, identifying the molecules responsible for initiation of blastema formation is an important aspect for understanding regeneration. Introns, a major source of noncoding RNAs (ncRNAs), have characteristic sizes in the axolotl, particularly in genes associated with development. These ncRNAs, particularly microRNAs (miRNAs), exhibit dynamic regulation during regeneration. These miRNAs play an essential role in timing and control of gene expression to order and organize processes necessary for blastema creation. Master keys or molecules that underlie the remarkable regenerative abilities of the axolotl remain to be fully explored and exploited. Further and ongoing research on regeneration promises new knowledge that may allow improved repair and renewal of human tissues.     

Reunderstanding Cairo through urban metabolism: Formal versus informal districts resource flow performance in fast urbanizing cities

Urban expansion can be seen as the most pervasive human impact on the environment where its high resource use contributes negatively to climate change and resource scarcity crises. Many experts call for decoupling resource use, economic development, and related urban development especially within cities of the Global South. This paper focuses on investigating resource efficiency through the lens of urban metabolism. It investigates current resource flows, through material flow analysis, from source to sink, in two diverse districts in Cairo: a formal district and an informal one, regarding materials (waste) and mobility. Consequently, the paper discusses locally responsive interventions that address local priorities as opposing to citywide one‐size fits all solution. The paper relies on parcel audits, which are embedded in an Urban Metabolism Information System developed by the Ecocity Builders and their partners, through a joint project with Cairo University. The methodology couples crowd‐sourced data, parcel audits, and experts’ knowledge to better understand resource flows based on a bottom‐up approach, given the unavailability of governmental data on the local level. The paper further correlates the perceived quality of life with the actual resource flows. It utilizes fieldwork investigations to argue against the local misconceptions regarding the inefficiency of informal areas/systems versus the higher efficiency of planned areas/systems. The paper concludes by proposing integrated solutions that respond to local needs and resources. It highlights the challenges and lessons of this tailored bottom‐up approach and its applicability in other cities worldwide.     

Osmotic Stress Responses and Plant Growth Controlled by Potassium Transporters in Arabidopsis

Osmotic adjustment plays a fundamental role in water stress responses and growth in plants; however, the molecular mechanisms governing this process are not fully understood. Here, we demonstrated that the KUP potassium transporter family plays important roles in this process, under the control of abscisic acid (ABA) and auxin. We generated Arabidopsis thaliana multiple mutants for K⁺ uptake transporter 6 (KUP6), KUP8, KUP2/SHORT HYPOCOTYL3, and an ABA-responsive potassium efflux channel, guard cell outward rectifying K⁺ channel (GORK). The triple mutants, kup268 and kup68 gork, exhibited enhanced cell expansion, suggesting that these KUPs negatively regulate turgor-dependent growth. Potassium uptake experiments using ⁸⁶radioactive rubidium ion (⁸⁶Rb⁺) in the mutants indicated that these KUPs might be involved in potassium efflux in Arabidopsis roots. The mutants showed increased auxin responses and decreased sensitivity to an auxin inhibitor (1-N-naphthylphthalamic acid) and ABA in lateral root growth. During water deficit stress, kup68 gork impaired ABA-mediated stomatal closing, and kup268 and kup68 gork decreased survival of drought stress. The protein kinase SNF1-related protein kinases 2E (SRK2E), a key component of ABA signaling, interacted with and phosphorylated KUP6, suggesting that KUP functions are regulated directly via an ABA signaling complex. We propose that the KUP6 subfamily transporters act as key factors in osmotic adjustment by balancing potassium homeostasis in cell growth and drought stress responses.     

Molecular Modeling of Disease Causing Mutations in Domain C1 of cMyBP-C

Cardiac myosin binding protein-C (cMyBP-C) is a multi-domain (C0–C10) protein that regulates heart muscle contraction through interaction with myosin, actin and other sarcomeric proteins. Several mutations of this protein cause familial hypertrophic cardiomyopathy (HCM). Domain C1 of cMyBP-C plays a central role in protein interactions with actin and myosin. Here, we studied structure-function relationship of three disease causing mutations, Arg177His, Ala216Thr and Glu258Lys of the domain C1 using computational biology techniques with its available X-ray crystal structure. The results suggest that each mutation could affect structural properties of the domain C1, and hence it’s structural integrity through modifying intra-molecular arrangements in a distinct mode. The mutations also change surface charge distributions, which could impact the binding of C1 with other sarcomeric proteins thereby affecting contractile function. These structural consequences of the C1 mutants could be valuable to understand the molecular mechanisms for the disease.