Intraband optical activity of semiconductor nanocrystals

Here we review our three recently developed analytical models describing the intraband optical activity of semiconductor nanocrystals, which is induced by screw dislocations, ionic impurities, or irregularities of the nanocrystal surface. The models predict that semiconductor nanocrystals can exhibit strong optical activity upon intraband transitions and have large dissymmetry of magnetic‐dipole absorption. The developed models can be used to interpret experimental circular dichroism spectra of nanocrystals and to advance the existing techniques of enantioseparation, biosensing, and chiral chemistry.     

Geochemical baseline determination and pollution assessment of heavy metals in urban soils of Karachi,Pakistan

Karachi is one of the most populated urban agglomerations in the world. No categorical study has yet discussed the geochemical baseline concentrations of metals in the urban soil of Karachi. The main objectives of this study were to establish geochemical baseline values and to assess the pollution status of different heavy metals. Geochemical baseline concentrations of heavy metals were estimated using the cumulative frequency distribution (CDF) curves. The estimated baseline concentrations of Pb, Cr, Cu, Zn and Fe were 56.23, 12.9, 36.31, 123.03 and 11,776 mg kg⁻¹, respectively. The pollution status of heavy metals in urban soils was evaluated using different quantitative indices (enrichment factor–EF, Geo-accumulation Index–I_geo, and pollution index–PI). Enrichments factors of the selected heavy metals determined by using Fe as a normalizer showed that metal contamination was the product of anthropogenic activities. The urban soils of Karachi were found to have a moderate to moderately severe enrichment with Pb, whereas Cr and Cu has moderate and Zn has minor enrichment. I_geo results indicated moderate soil contamination by Pb at some of the sampling locations. PI for Pb, Cr, Cu and Zn was found in the range of 0.04–3.42, 0.19–1.55, 0.27–2.45 and 0.32–1.57, respectively. Large variations in PI values of Pb revealed that soil in those areas of the city which are influenced by intensive anthropogenic activities have exceptionally high concentrations of Pb. The findings of this study would contribute to the environmental database of the soil of the region and would also facilitate both at the local and the international scales, in a more accurate global environmental monitoring, which will eventually facilitate the development of management and remediation strategies for heavy metal contaminated urban soil.     

Epidermal growth factor increases P incorporation into phosphatidylcholine and protein kinase C activity in colon carcinoma cell line (HT29)

There are conflicting data about the effect of the epidermal growth factor (EGF) on protein kinase C (PKC) enzyme activity. The aim of our study was to find out which type of phospholipids [phosphatidylinositol 4,5-bisphosphate P14,5P₂ or the other phospholipids-phosphatidylcholine (PC) or phosphatidic acid (PA)] could be the source of 1,2-diacylglycerol (1,2-DAG) in PKC activation. In colon carcinoma cells (HT29) we observed a more than 2-fold increase in the PC pool and at the same time decreased tyrosine kinase activity (50%). With increasing incubation time EGF affects the pools of both phosphatidylinositols and other phospholipids parallel with the activation of the tyrosine kinase activity. EGF increases the activity of PKC in the HT29 cell line and PC could be the source of 1,2-DAG which may stimulate PKC activity.     

VEGF-C attenuates renal damage in salt-sensitive hypertension

Salt-sensitive hypertension is a major risk factor for renal impairment leading to chronic kidney disease. High-salt diet leads to hypertonic skin interstitial volume retention enhancing the activation of the tonicity-responsive enhancer-binding protein (TonEBP) within macrophages leading to vascular endothelial growth factor C (VEGF-C) secretion and NOS3 modulation. This promotes skin lymphangiogenesis and blood pressure regulation. Whether VEGF-C administration enhances renal and skin lymphangiogenesis and attenuates renal damage in salt-sensitive hypertension remains to be elucidated. Hypertension was induced in BALB/c mice by a high-salt diet. VEGF-C was administered subcutaneously to high-salt-treated mice as well as control animals. Analyses of kidney injury, inflammation, fibrosis, and biochemical markers were performed in vivo. VEGF-C reduced plasma inflammatory markers in salt-treated mice. In addition, VEGF-C exhibited a renal anti-inflammatory effect with the induction of macrophage M2 phenotype, followed by reductions in interstitial fibrosis. Antioxidant enzymes within the kidney as well as urinary RNA/DNA damage markers were all revelatory of abolished oxidative stress under VEGF-C. Furthermore, VEGF-C decreased the urinary albumin/creatinine ratio and blood pressure as well as glomerular and tubular damages. These improvements were associated with enhanced TonEBP, NOS3, and lymphangiogenesis within the kidney and skin. Our data show that VEGF-C administration plays a major role in preserving renal histology and reducing blood pressure. VEGF-C might constitute an interesting potential therapeutic target for improving renal remodeling in salt-sensitive hypertension.     

The NADH Dehydrogenase Nde1 Executes Cell Death after Integrating Signals from Metabolism and Proteostasis on the Mitochondrial Surface

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The Differential Role of Protein Kinase C Isozyme in the Rapid Induction of Neurofilament Phosphorylation by Nerve Growth Factor and Phorbol Esters in PC12 Cells

We examined the short-term regulation of the phosphorylation of the mid-sized neurofilament subunit (NF-M) by kinases which were activated in rat pheochromocytoma (PC12) cells by nerve growth factor (NGF) and/or 12-O-tetradecanoylphorbol 13-acetate (TPA). We found that NGF and TPA, alone or in combination, increased (a) the incorporation of [32P]Pi into NF-M and (b) the rate of conversion of NF-M from a poorly phosphorylated to a more highly phosphorylated form. This was not due to increased synthesis of NF-M, because NGF alone did not increase NF-M synthesis and TPA alone or TPA and NGF together inhibited the synthesis of NF-M. Further, an increase in calcium/phospholipid-dependent kinase (PKC) activity resulting from the treatment of PC12 cells with NGF and TPA was observed concomitant with the increased phosphorylation of NF-M. This PKC activity was determined to be derived from the PKC alpha and PKC beta isozymes. Finally, when PC12 cells were rendered PKC-deficient by treatment with 1 muM TPA for 24 h, NGF maintained the ability to induce an increase in NF-M phosphorylation, though not to the level attained in cells which were not PKC-deficient. These data suggest that NGF with or without TPA stimulates NF-M phosphorylation as a result of a complex series of events which include PKC-independent and PKC-dependent pathways.     

Human cell lines for biopharmaceutical manufacturing: history,status, and future perspectives

Biotherapeutic proteins represent a mainstay of treatment for a multitude of conditions, for example, autoimmune disorders, hematologic disorders, hormonal dysregulation, cancers, infectious diseases and genetic disorders. The technologies behind their production have changed substantially since biotherapeutic proteins were first approved in the 1980s. Although most biotherapeutic proteins developed to date have been produced using the mammalian Chinese hamster ovary and murine myeloma (NS0, Sp2/0) cell lines, there has been a recent shift toward the use of human cell lines. One of the most important advantages of using human cell lines for protein production is the greater likelihood that the resulting recombinant protein will bear post-translational modifications (PTMs) that are consistent with those seen on endogenous human proteins. Although other mammalian cell lines can produce PTMs similar to human cells, they also produce non-human PTMs, such as galactose-α1,3-galactose and N-glycolylneuraminic acid, which are potentially immunogenic. In addition, human cell lines are grown easily in a serum-free suspension culture, reproduce rapidly and have efficient protein production. A possible disadvantage of using human cell lines is the potential for human-specific viral contamination, although this risk can be mitigated with multiple viral inactivation or clearance steps. In addition, while human cell lines are currently widely used for biopharmaceutical research, vaccine production and production of some licensed protein therapeutics, there is a relative paucity of clinical experience with human cell lines because they have only recently begun to be used for the manufacture of proteins (compared with other types of cell lines). With additional research investment, human cell lines may be further optimized for routine commercial production of a broader range of biotherapeutic proteins.     

Two-hit wonders: The expanding universe of multitargeting epigenetic agents

Multitargeting involves the application of molecules that are deliberately intended to bind to two or more unrelated cellular targets with high affinity. In epigenetic chemical biology and drug discovery, the rational design of multitargeting agents has evolved to a sophisticated level, and there are now five examples that have reached clinical trials. This review covers recent developments in the field and future prospects.     

Isocitrate dehydrogenase variants in cancer — Cellular consequences and therapeutic opportunities

Abnormal metabolism is common in cancer cells and often correlates with mutations in genes encoding for enzymes involved in small-molecule metabolism. Isocitrate dehydrogenase 1 (IDH1) is the most frequently mutated metabolic gene in cancer. Cancer-associated substitutions in IDH1 and IDH2 impair wild-type production of 2-oxoglutarate and reduced nicotinamide adenine dinucleotide phosphate (NADPH) from isocitrate and oxidised nicotinamide adenine dinucleotide phosphate (NADP⁺ ), and substantially promote the IDH variant catalysed conversion of 2-oxoglutarate to d-2-hydroxyglutarate (d-2HG). Elevated d-2HG is a biomarker for some cancers, and inhibition of IDH1 and IDH2 variants is being pursued as a medicinal chemistry target. We provide an overview of the types of cancer-associated IDH variants, discuss some of the proposed consequences of altered metabolism as a result of elevated d-2HG, summarise therapeutic efforts targeting IDH variants and identify areas for future research.