The effect of temperature on antibacterial activity of biosynthesized silver nanoparticles

The purpose of this study was the evaluation of two different temperatures on antibacterial activity of the biosynthesized silver nanoparticles. 38 silver nanoparticles-producing bacteria were isolated from soil and identified. Biosynthesis of silver nanoparticles by these bacteria was verified through visible light spectrophotometry. Two strains were relatively active for production of silver nanoparticles. These strains were subjected for molecular identification and recognized as Bacillus sp. and Acinetobacter schindleri. In the present study, the effect of temperatures was evaluated on structure and antimicrobial properties of the silver nanoparrticles by transmission electron microscopy (TEM), X-ray diffraction (XRD) analysis and antimicrobial Agar well diffusion methods. The silver nanoparticles showed antibacterial activity against all the pathogenic bacteria; however, this property was lost after treatment of the silver nanoparticles by high temperatures (100 and 300 °C). TEM images showed that the average sizes of heated silver nanoparticles were >100 nm. However, these were <100 nm for non-heated silver nanoparticles. Although, XRD patterns showed the crystalline structure of heated silver nanoparticles, their antibacterial activities were less. This was possible because of the sizes and accordingly less penetration of the particles into the bacterial cells. In addition, elimination of the capping agents by heat might be considered another reason.     

CD271 enrichment does not help isolating mesenchymal stromal cells from G-CSF-mobilized peripheral blood

Reports on the isolation of mesenchymal stromal cells (MSCs) from granulocyte colony stimulating factor mobilized peripheral blood (G-CSF-mobilized PB) using regular culturing techniques are controversial. Enrichment techniques such as CD133 isolation have increased the success rates. CD271 is a wellknown marker for enrichment of MSCs from bone marrow (BM). In the present study, we aimed to find out whether CD271 enrichment can help isolation of MSCs from G-CSF-mobiiized PB. Five G-CSF-mobilized PB samples were collected from the remnant parts of the bags used for BM transplantation. Five BM samples were used as the control. Mononuclear cells (MNCs) from both resources were collected and underwent magnetic sorting for CD271-positive cells. The isolated cells were cultured, undergoing flowcytometry and differentiation assays to determine if they fulfill MSCs characteristics. CD271-positive portion of G-CSF-mobilized PB did not yield any cell outgrowth but the BM counterpart could successfully form MSC colonies. Although the percentage of CD271⁺ cells showed no difference between BM-MNCs and G-CSF-mobilized PB-MNCs, hematopoietic markers such as CD45, CD34 and CD133 composed a higher percentage of CD271-positive cells in the G-CSF-tnobiiized PB group. Results obtained indicated that CD271 enrichment does not help isolation of MSCs from G-CSF-mobilized PB. In this source, almost all of the CD271⁺ cells are from hematopoietic origin and the frequency of MSCs is so low that possibly during the process of cell isolation most of them are lost and the isolation fails.     

Evaluation of the adjuvant activity of naloxone,an opioid receptor antagonist,in combination with heat-killed Listeria monocytogenes vaccine

We have previously demonstrated the adjuvant activity of naloxone (NLX), a general opioid antagonist, using a DNA vaccine for herpes simplex virus type 1. Here, the adjuvant activity of NLX has been evaluated using a heat-killed Listeria monocytogenes (HKLM) vaccine as a model for general immunization against intracellular bacteria. BALB/c mice were divided into three groups: the Vac group received the HKLM vaccine alone; the NLX–Vac group received the HKLM vaccine in combination with the adjuvant NLX; and the control group received phosphate buffered saline (PBS). Our results indicate that the administration of NLX as an adjuvant enhances the ability of the HKLM vaccine to increase lymphocyte proliferation, delayed type hypersensitivity, and skewing of the immune response toward a T-helper 1 (Th1) pattern. Additionally, combination of NLX with the HKLM vaccine improves protective immunity against L. monocytogenes. In conclusion, administration of NLX as an adjuvant for the HKLM vaccine can enhance cell-mediated immunity and shift the immune response to Th1.     

Reconstructing speech from human auditory cortex

How the human auditory system extracts perceptually relevant acoustic features of speech is unknown. To address this question, we used intracranial recordings from nonprimary auditory cortex in the human superior temporal gyrus to determine what acoustic information in speech sounds can be reconstructed from population neural activity. We found that slow and intermediate temporal fluctuations, such as those corresponding to syllable rate, were accurately reconstructed using a linear model based on the auditory spectrogram. However, reconstruction of fast temporal fluctuations, such as syllable onsets and offsets, required a nonlinear sound representation based on temporal modulation energy. Reconstruction accuracy was highest within the range of spectro-temporal fluctuations that have been found to be critical for speech intelligibility. The decoded speech representations allowed readout and identification of individual words directly from brain activity during single trial sound presentations. These findings reveal neural encoding mechanisms of speech acoustic parameters in higher order human auditory cortex.     

Material translations in the Cartesian brain

This article reexamines the controversial doctrine of the pineal gland in Cartesian psychophysiology. It argues initially that Descartes' combined metaphysics and natural philosophy yield a distinctly human subject who is rational, willful, but also a living and embodied being in the world, formed in the union and through the dynamics of the interaction between the soul and the body. However, Descartes only identified one site at which this union was staged: the brain, and more precisely, the pineal gland, the small bulb of nervous tissue at the brain's center. The pineal gland was charged with the incredible task of ensuring the interactive mutuality between the soul and body, while also maintaining the necessary ontological incommensurability between them. This article reconsiders the theoretical obligations placed on the pineal gland as the site of the soul-body union, and looks at how the gland was consequently forced to adopt a very precarious ontological status. The article ultimately questions how successfully the Cartesian human could be localized in the pineal gland, while briefly considering the broader historical consequences of the ensuing equivalence of the self and brain.     

Cytokine single nucleotide polymorphisms in Iranian patients with pulmonary tuberculosis

BACKGROUND: Several genes coding for different cytokines may affect host susceptibility to tuberculosis. METHODS: In the present study, the allele and genotype frequencies of a number polymorphic genes coding for cytokines or cytokine receptors were investigated in Iranian patients with pulmonary tuberculosis (PTB). RESULTS: From the IL-1 cluster, a positive, significant difference was found at position -889, where the T/T genotype was over represented in PTB patients (p = 0.01); a positive, significant increase was found in the IL1R PstI 1970 C/C genotype, where the C allele was over represented in the PTB patients (p = 0.01). A significant negative association at codon 10 TGF-beta, T allele, was shown in our patients and the C allele and C/C genotype were over represented in the PTB patients (P<0.005). For TNF-alpha at position -238, we found a negative association for the G/A genotype and a positive association for the G/G genotype (p = 0.0009). Significant negative associations at position -590 IL-4, T allele and the T/T genotype were shown in our patients (p = 0.0007); also, the C allele and T/C genotype were significantly increased in our patients (P<0.05). With IL-6 at -174, G/G increased and G/C decreased significantly in the patients (P<0.005). CONCLUSION: Pro-inflammatory cytokines such as TNF-alpha and TGF-beta seem to be decreased, and IL-6 increased in PTB patients.