Susceptibility of Leishmania to novel pentavalent organometallics: Investigating impact on DNA and membrane integrity in antimony(III)-sensitive and -resistant strains

The aim the present study was to investigate the impact of novel pentavalent organobismuth and organoantimony complexes on membrane integrity and their interaction with DNA, activity against Sb(III)-sensitive and -resistant Leishmania strains and toxicity in mammalian peritoneal macrophages. Ph3M(L)2 type complexes were synthesized, where M = Sb(V) or Bi(V) and L = deprotonated 3-(dimethylamino)benzoic acid or 2-acetylbenzoic acid. Both organobismuth(V) and organoantimony(V) complexes exhibited efficacy at micromolar concentrations against Leishmania amazonensis and L. infantum but only the later ones demonstrated biocompatibility. Ph3Sb(L1)2 and Ph3Bi(L1)2 demonstrated distinct susceptibility profiles compared to inorganic Sb(III)-resistant strains of MRPA-overexpressing L. amazonensis and AQP1-mutated L. guyanensis. These complexes were able to permeate the cell membrane and interact with the Leishmania DNA, suggesting that this effect may contribute to the parasite growth inhibition via apoptosis. Taken altogether, our data substantiate the notion of a distinct mechanism of uptake pathway and action in Leishmania for these organometallic complexes, distinguishing them from the conventional inorganic antimonial drugs.

Biomedical Applications of Green Synthesized Zinc Oxide and Magnesium-Doped Zinc Oxide Nanoparticles Using Aqueous Extract of Ziziphus Oxyphylla Leaves

Zinc oxide (ZnO) and magnesium-doped zinc oxide (Mg-doped ZnO) nanoparticles (NPs) were synthesized using Ziziphus oxyphylla's aqueous leaf extract as reducing agent. UV-Vis absorption peaks at 324 nm and 335 nm were indicative of ZnO and Mg-doped ZnO, respectively. FTIR absorption bands observed at 3238, 1043, 1400, 1401, 2186 and 2320 cm-1 suggested the presence of phenols, alcohols, saturated hydrocarbons, and possibly alkynes. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy revealed pure, spherical and agglomerated NPs with average size of 35.9 nm (ZnO) and 56.8 nm (Mg-doped ZnO). Both NPs remained active against all bacterial strains with the highest inhibition zones observed against Proteus vulgaris (21.16±1.25 mm for ZnO and 24.1±0.76 mm for Mg-doped ZnO. EtBr fluorescence (cartwheel assay) indicated efflux pump blockage, suggesting its facilitation in the bacterial growth inhibition. Antioxidant potential, determined via DPPH radical scavenging assay, revealed stronger antioxidant potential for Mg-doped ZnO (IC50 21.53±0.76 μg/mL) than pure ZnO (IC50 30.32±0.73 μg/mL). Furthermore, both NPs showed antileishmanial activity against Leishmania tropica promastigotes (IC50 47.23±3.22 μg/mL for Mg-doped ZnO and 64.34±6.56 for ZnO), while neither NP exhibited significant hemolysis, indicating biocompatibility and further assessment for their drugability.

Adsorption of a thione derivative on carbon, AlN, and BN nanotubes: a detailed DFT and MD investigation

The performance of nanotubes (NT) of carbon (CC), aluminium-nitrogen (AlN), and boron-nitrogen (BN) as a sensor and nanocarrier for mercaptopurine (MCP) was investigated by means of a theoretical approach. The calculated negative values of adsorption energy showed the interaction and adsorption of MCP. Highest-occupied molecular orbital (HOMO) and lowest-unoccupied molecular orbital (LUMO) distributions were only found on the NT counter portion of the drug-nanotube not on MCP for AlN-NT and BN-NT while HOMO is over MCP and LUMO is over NT for CC-NT. The polarizability of MCP-NTs is greater than that of MCP. Raman wavenumbers of MCP are enhanced in NTs, and hence, NTs can act as a sensor for the detection of MCP. Solvent dependency on adsorption behaviour is also presented in the manuscript, where we found that the AlN nanotube showed exceptionally high free energy of adsorption over other nanotubes in all solvent mediums. Solvation-free energies were also reported. Noncovalent interaction scattered plot also showed significant intermolecular interaction between AlN nanotubes and the mercaptopurine when compared to other nanotubes under study. To find the antiviral activity of MCP and MCP-NTs against antiviral activities, docking and molecular dynamics simulations were performed with 1HMP PDB. Recovery times show that MCP desorption occurs quickly. The MD simulations and docking results show that BN and CC-NTs with MCP show good activity as drug carriers.

Heredity of type 2 diabetes confers increased susceptibility to oxidative stress and inflammation

INTRODUCTION AND OBJECTIVE

Heredity of type 2 diabetes mellitus (T2DM) is associated with greater risk for developing T2DM. Thus, individuals who have a first-degree relative with T2DM (FDRT) provide a natural model to study factors of susceptibility towards development of T2DM, which are poorly understood. Emerging key players in T2DM pathophysiology such as adverse oxidative stress and inflammatory responses could be among possible mechanisms that predispose FDRTs to develop T2DM. Here, we aimed to examine the role of oxidative stress and inflammatory responses as mediators of this excess risk by studying dynamic postprandial responses in FDRTs.

RESEARCH DESIGN AND METHODS

In this open-label case-control study, we recruited normoglycemic men with (n=9) or without (n=9) a family history of T2DM. We assessed plasma glucose, insulin, lipid profile, cytokines and F₂-isoprostanes, expression levels of oxidative and inflammatory genes/proteins in circulating mononuclear cells (MNC), myotubes and adipocytes at baseline (fasting state), and after consumption of a carbohydrate-rich liquid meal or insulin stimulation.

RESULTS

Postprandial glucose and insulin responses were not different between groups. Expression of oxidant transcription factor NRF2 protein (p<0.05 for myotubes) and gene (p_group=0.002, p_time×group=0.016), along with its target genes TXNRD1 (p_group=0.004, p_time×group=0.007), GPX3 (p_group=0.011, p_time×group=0.019) and SOD-1 (p_group=0.046 and p_time×group=0.191) was upregulated in FDRT-derived MNC after meal ingestion or insulin stimulation. Synergistically, expression of target genes of inflammatory transcription factor nuclear factor kappa B such as tumor necrosis factor alpha (p_group=0.001, p_time×group=0.007) was greater in FDRT-derived MNC than in non-FDRT-derived MNC after meal ingestion or insulin stimulation.

CONCLUSIONS

Our findings shed light on how heredity of T2DM confers increased susceptibility to oxidative stress and inflammation. This could provide early insights into the underlying mechanisms and future risk of FDRTs for developing T2DM and its associated complications.

Two distinct interstitial macrophage populations coexist across tissues in specific subtissular niches

Macrophages are a heterogeneous cell population involved in tissue homeostasis, inflammation, and various pathologies. Although the major tissue-resident macrophage populations have been extensively studied, interstitial macrophages (IMs) residing within the tissue parenchyma remain poorly defined. Here we studied IMs from murine lung, fat, heart, and dermis. We identified two independent IM subpopulations that are conserved across tissues: Lyve1^loMHCII^hiCX3CR1^hi (Lyve1^loMHCII^hi) and Lyve1^hiMHCII^loCX3CR1^lo (Lyve1^hiMHCII^lo) monocyte-derived IMs, with distinct gene expression profiles, phenotypes, functions, and localizations. Using a new mouse model of inducible macrophage depletion (Slco2b1 ^flox/DTR), we found that the absence of Lyve1^hiMHCII^lo IMs exacerbated experimental lung fibrosis. Thus, we demonstrate that two independent populations of IMs coexist across tissues and exhibit conserved niche-dependent functional programming.

Genes Involved in Oxidative Stress Pathways Are Differentially Expressed in Circulating Mononuclear Cells Derived From Obese Insulin-Resistant and Lean Insulin-Sensitive Individuals Following a Single Mixed-Meal Challenge

Background: Oxidative stress induced by nutritional overload has been linked to the pathogenesis of insulin resistance, which is associated with metabolic syndrome, obesity, type 2 diabetes and diabetic vascular complications. Postprandial changes in expression of oxidative stress pathway genes in obese vs. lean individuals, following intake of different types of meals varying in macronutrient composition have not been characterized to date. Here we aimed to test whether/how oxidative stress responses in obese vs. lean individuals are modulated by meal composition. Methods: High-carbohydrate (HC), high-fat (HF), or high-protein (HP) liquid mixed meals were administered to study subjects (lean insulin-sensitive, n = 9 and obese insulin-resistant, n = 9). Plasma levels of glucose and insulin, lipid profile, urinary F₂-isoprostanes (F₂-IsoP), and expression levels of genes of oxidative stress pathways were assessed in mononuclear cells (MNC) derived from fresh peripheral blood, at baseline and up to 6-h postprandial states. Differences in these parameters were compared between insulin-sensitive/resistant groups undergoing aforementioned meal challenges. Results: Obese individuals exhibited increased pro-oxidant (i.e., CYBB and CYBA) and anti-oxidant (i.e., TXN RD1) gene expression in the postprandial state, compared with lean subjects, regardless of meal type (P interaction for group × time < 0.05). By contrast, lean subjects had higher expression of NCF-4 gene (pro-oxidant) after HC meal and SOD1 gene (anti-oxidant) after HC and HF meals (P interaction for group × meal < 0.05). There was an increase in postprandial level of urinary F₂-IsoP in the obese (P < 0.05) but not lean group. Conclusions: These findings may represent an adaptive oxidative response to mitigate increased stress induced by acute nutritional excess. Further, the results suggest an increased predisposition of obese subjects to oxidative stress. Chronic nutritional excess resulting in increases in body weight and adiposity might lead to decompensation leading to worsening insulin resistance and its sequel. Insights from this study could impact on nutritional recommendations for obese subjects at high-risk of cardiovascular diseases.

Meal rich in carbohydrate, but not protein or fat, reveals adverse immunometabolic responses associated with obesity

Background

Obesity-related insulin resistance is linked to inflammation. Immunometabolic function differs between lean and obese subjects, but whether macronutrient composition of ingested meals affects these responses is not well known. We examined the effects of a single meal rich in fat, protein, or carbohydrate on immunometabolic responses.

Methods

Nine lean insulin sensitive (LIS) men and 9 obese insulin resistant (OIR) men ingested high-carbohydrate (HC), high-fat (HF) or high-protein (HP) mixed meals in random order. We assessed plasma glucose, insulin, and cytokine responses and cytokine gene expression in circulating mononuclear cells (MNC) at fasting and postprandial states (up to 6-h).

Results

Expression of NF-κB and TNFα genes were greater; whereas that of TGFβ and IL-6 genes were lower, in the OIR compared to the LIS individuals. The differences were significantly greater after the HC meal, but not after the HP or HF meal. Similar results were obtained for plasma concentrations of TNFα and IL-6.

Conclusions

Our findings indicate that a single HC meal has a distinct adverse effect on immunometabolic responses in the OIR individuals. The cumulative effect of such adverse responses to meals rich in carbohydrate may predispose the OIR individuals to a higher risk of cardiovascular disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s12937-016-0219-0) contains supplementary material, which is available to authorized users.

Metabolic gene expression profile in circulating mononuclear cells reflects obesity-associated metabolic inflexibility

BACKGROUND

Obesity is associated with an impaired ability to switch from fatty acid to glucose oxidation during the fasted to fed transition, particularly in skeletal muscle. However, whether such metabolic inflexibility is reflected at the gene transcription level in circulatory mononuclear cells (MNC) is not known.

METHODS

The whole-body respiratory quotient (RQ) and transcriptional regulation of genes involved in carbohydrate and lipid metabolism in MNC were measured during fasting and in response (up to 6 h) to high-carbohydrate and high-fat meals in nine lean insulin-sensitive and nine obese insulin-resistant men.

RESULTS

Compared to lean subjects, obese subjects had an impaired ability to increase RQ and switch from fatty acid to glucose oxidation following the high-carbohydrate meal (interaction term P < 0.05). This was accompanied by an impaired induction of genes involved in oxidative metabolism of glucose in MNC, such as phosphofructokinase (PFK), pyruvate dehydrogenase kinase 4 (PDK4), peroxisome proliferator-activated receptor alpha (PPARα) and uncoupling protein 3 (UCP3) and increased expression of genes involved in fatty acid metabolism, such as fatty acid translocase (FAT/CD36) and fatty acid synthase (FASN) (P < 0.05). On the contrary, there were no differences in the gene expression profiles between lean and obese subjects following the high-fat meal.

CONCLUSIONS

Postprandial expression profiles of genes involved in glucose and fatty acid metabolism in the MNC reflect the differing metabolic flexibility phenotypes of our cohort of lean and obese individuals. These differences in metabolic flexibility between the lean and obese are elicited by an acute meal challenge that is rich in carbohydrate but not fat.

Crystal structure of methyl 2-(7-hy-droxy-2-oxo-2H-chromen-4-yl)acetate

In the title coumarin derivative, C₁₂H₁₀O₅, the fused ring system is almost planar (r.m.s deviation = 0.016 Å). The C_ar—C—C=O torsion angle of the side chain is −8.4 (2)° In the crystal, mol­ecules are linked by O—H⋯O hydrogen bonds, generating C(8) chains propagating in the [100] direction. The chains are cross-linked by weak C—H⋯O inter­actions, thereby generating undulating (001) sheets.

Programmable fiber/integrated-optics bipolar tap

A programmable bipolar tap implementation is described. The proposed scheme utilizes fiber and integrated-optics technology in conjunction with twos complement number representation and digital multiplication by an analog convolution algorithm. Simple experimental verification of the scheme is presented.

Fiber-optic matrix multiplier using a two-dimensional systolic-array architecture

An optical matrix multiplier based on a two-dimensional systolic-array architecture is described, exploiting the parallelism offered by optical methods. Experimental verification of multiplier performance is presented. A technique for multiple matrix multiplications is suggested.

Fiber-optic bipolar tap implementation using an incoherent optical source

A fiber-optic bipolar tap implementation is described. The proposed scheme utilizes 2's complement-number representation and digital multiplication by an analog convolution algorithm. Simple experimental verification of the scheme is presented. The addition of programmability to the taps results in the realization of a fast, flexible processor for manipulating binary quantities.