BLT1-mediated O-GlcNAcylation is required for NOX2-dependent migration, exocytotic degranulation and IL-8 release of human mast cell induced by Trichomonas vaginalis-secreted LTB4

Publication date: Available online 31 May 2018
Source:Microbes and Infection
Author(s): Arim Min, Young Ah Lee, Kyeong Ah Kim, Myeong Heon Shin
Trichomonas vaginalis is a sexually-transmitted protozoan parasite that causes vaginitis and cervicitis. Although mast cell activation is important for provoking tissue inflammation during infection with parasites, information regarding the signaling mechanisms in mast cell activation and T. vaginalis infection is limited. O-linked N-acetylglucosamine (O-GlcNAc) is a post-translational modification of serine and threonine residues that functions as a critical regulator of intracellular signaling, regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). We investigated if O-GlcNAcylation was associated with mast cell activation induced by T. vaginalis-derived secretory products (TvSP). Modified TvSP collected from live trichomonads treated with the 5-lipooxygenase inhibitor AA861 inhibited migration of mast cells. This result suggested that mast cell migration was caused by stimulation of T. vaginalis-secreted leukotrienes. Using the BLT1 antagonist U75302 or BLT1 siRNA, we found that migration of mast cells was evoked via LTB4 receptor (BLT1). Furthermore, TvSP induced protein O-GlcNAcylation and OGT expression in HMC-1 cells, which was prevented by transfection with BLT1 siRNA. TvSP-induced migration, ROS generation, CD63 expression and IL-8 release were significantly suppressed by pretreatmemnt with OGT inhibitor ST045849 or OGT siRNA. These results suggested that BLT1-mediated OGlcNAcylation was important for mast cell activation during trichomoniasis.



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Geographic distribution of livestock-associated Staphylococcus aureus in the United States

Publication date: Available online 31 May 2018
Source:Microbes and Infection
Author(s): Tara C. Smith, Dipendra Thapaliya, Sabana Bhatta, Samantha Mackey, Jean Engohang-Ndong, Margaret Carrel
Sampling for livestock-associated Staphylococcus aureus (LA-SA) in the United States is haphazard. The diversity of LA-S. aureus in the U.S. appears to be greater than in other countries. We review the epidemiology of LA-S. aureus in U.S. pigs, occupationally-exposed individuals, and environmental samples to assess the diversity and abundance of U.S. LA-S. aureus.



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Activity of acetylcholinesterase and acid and alkaline phosphatases in different insecticide-treated Helicoverpa armigera (Hübner)

Abstract

Helicoverpa armigera is a major devastating insect pest on a wide range of vegetables and cash crops. Insecticides are presently indispensable for its control in nearly all crops. H. armigera has acquired resistance against almost all insecticides because of the activity of detoxification enzymes used for the defensive mechanism. The current research was carried out to evaluate the activity of detoxification enzymes, i.e., acetylcholinesterase and alkaline and acid phosphatases in chlorpyrifos-, bifenthrin-, lufenuron-, lambda cyhalothrin-, and emamectin benzoate-treated larvae of H. armigera. The maximum AChE activity was recorded in emamectin benzoate-treated larval samples followed by chlorpyrifos, lufenuron, lambda cyhalothrin and bifenthrin, respectively, while the highest alkaline phosphatases' activity was recorded in emamectin and the lowest in bifenthrin-treated H. armigera. As far as acid phosphatases' activity is concerned, the highest activity was noted in lufenuron samples while the lowest in lambda cyhalothrin samples, respectively. Comparatively, activities of alkaline and acid phosphatases were higher than AChE. The elevated activities of detoxification enzymes can possibly lead to increase in resistance development against synthetic chemical insecticides.

https://ift.tt/2J2jSC9

Mannosyl electrochemical impedance cytosensor for label-free MDA-MB-231 cancer cell detection

Publication date: 30 September 2018
Source:Biosensors and Bioelectronics, Volume 116
Author(s): Yi-Hsuan Tang, Han-Chen Lin, Chiao-Ling Lai, Po-Yu Chen, Chian-Hui Lai
A label-free and ultrasensitive electrochemical impedance cytosensor was developed to specifically detect the breast cancer cells MDA-MB-231 via the interaction between the mannosyl glassy carbon electrode (GCE) and the overexpressed mannose receptors on the target cell surface. The mannosyl GCE was prepared through electrografting of the amino-functionalized mannose derivatives on GCE surface in which a covalent bond was formed between carbon of the electrode and the amino group of the mannose derivative. The fluorescent microscopy indicated that the electrode is specific for MDA-MB-231 cells, with good biocompatibility for viable captured cells. The derivative with a shorter alkyl linker, mannose-C2NH2, showed a better sensitivity than that with a longer linker, mannose-C6NH2. GCE modified with amino-functionalized galactose derivative, galactose-C2NH2, shows no function to the detection of MDA-MB-231 cells. The specific interaction between the mannosyl GCE and Con A (a mannose-binding lectin) or MDA-MB-231 breast cancer cells with overexpressed mannose receptors was determined through the change of peak separation in the cyclic voltammogram or the change of charge transfer resistance in the electrochemical impedance spectra (Nyquist plot) in the electrolytes containing a reversible redox couple [Fe(CN)6]³⁻/[Fe(CN)6]⁴⁻. The charge transfer resistance in the Nyquist plots linearly depended on the concentration of MDA-MB-231 cells (1.0 × 10–1.0 × 10⁵ cells mL⁻¹, with 10 cells mL⁻¹ being the lower detection limit). Introducing 0.1% polyethylene glycol-200 (PEG-200) was able to prevent the interference caused by 1.0 × 10³ HEK-293T cells mL⁻¹, a non-cancer cell line (control).

Graphical abstract

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Ultrasensitive dual probe immunosensor for the monitoring of nicotine induced-brain derived neurotrophic factor released from cancer cells

Publication date: 30 September 2018
Source:Biosensors and Bioelectronics, Volume 116
Author(s): Mahmood H. Akhtar, Khalil K. Hussain, N.G. Gurudatt, Pranjal Chandra, Yoon-Bo Shim
Brain-derived neurotrophic factor (BDNF) was detected in the extracellular matrix of neuronal cells using a dual probe immunosensor (DPI), where one of them was used as a working and another bioconjugate loading probe. The working probe was fabricated by covalently immobilizing capture anti-BDNF (Cap Ab) on the gold nanoparticles (AuNPs)/conducting polymer composite layer. The bioconjugate probe was modified by drop casting a bioconjugate particles composed of conducting polymer self-assembled AuNPs, immobilized with detection anti-BDNF (Det Ab) and toluidine blue O (TBO). Each sensor layer was characterized using the surface analysis and electrochemical methods. Two modified probes were precisely faced each other to form a microfluidic channel structure and the gap between inside modified surfaces was about 19 µm. At optimized conditions, the DPI showed a linear dynamic range from 4.0 to 600.0 pg/ml with a detection limit of 1.5 ± 0.012 pg/ml. Interference effect of IgG, arginine, glutamine, serine, albumin, and fibrinogene were examined and stability of the developed biosensor was also investigated. The reliability of the DPI sensor was evaluated by monitoring the extracellular release of BDNF using exogenic activators (ethanol, K⁺, and nicotine) in neuronal and non-neuronal cells. In addition, the effect of nicotine onto neuroblastoma cancer cells (SH-SY5Y) was studied in detail.



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Parameters of skull vibration-induced nystagmus in normal subjects

Abstract

Hypothesis

The knowledge of vibration-induced nystagmus test (SVINT) values in the normal population is highly relevant to provide a rapid orientation on the diagnosis attitude in a patient with vertigo.

Background

Although mastoid bone vibration should only induce nystagmus in the presence of vestibular asymmetry, it has also been reported in normal individuals raising doubts as to how to interpret the SVINT. To date, no population studies involving the use of the SVINT and that establish normative values have been published.

Methods

This study was carried out at two tertiary healthcare centres on a total of 122 subjects. We stimulated at three frequencies (30, 60 and 100 Hz), in increasing order, first stimulating the right mastoid and then the left mastoid, and waiting for 30 s between each stimulus. The response was recorded with a videonystagmography system. The following variables were evaluated in each subject: the mean and maximum speed of the slow phase of nystagmus, the frequency of the nystagmatic response (NR) and the component and direction of the rapid phase of nystagmus.

Results

Only 26 subjects (20.5%) of the subjects studied here (122 subjects) developed any kind of nystagmatic response and 96 subjects (79.5%) did not display any response. Stimulation at 100 Hz provoked the largest number of responses (p = 0.04), while there was no difference in the number of responses induced by 30 and 60 Hz stimulations (p = 0.85). The frequency of nystagmus was ≤ 0.7 n/s in 80.8% of the positive responses. The mean velocity of the horizontal component of the NR was 2.2°/s (SD 1.6) and that of the vertical component was 1.3°/s (SD 1.2).

Conclusions

Healthy subjects do not generally develop to NR upon vibratory stimulation and only 20% of the subjects studied here developed any kind of NR, this being a slow and inconsistent response of low frequency. The establishment of normal values contributes to improve the orientation in clinical practice in the pathological population and this opens possibilities for tackling more reliable studies in this population.

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HER1-based vaccine: simultaneous activation of humoral and cellular immune response

Publication date: Available online 31 May 2018
Source:Seminars in Oncology
Author(s): Gretchen Bergado Báez, Diana R. Hernández Fernández, Zaima Mazorra Herrera, Belinda Sánchez Ramírez
The human epidermal growth factor receptor 1 (HER1) is a tumor associated antigen that has been validated as a clinical target for several passive, non-immune therapies currently approved for the treatment epithelial tumors. HER1 is an oncogene that not only promotes tumor progression and survival, but also immune-escape. Its overexpression in some epithelial malignancies has been correlated with a poor prognosis. We developed an approach to target HER1 by specific active immunotherapy, recognizing the extracellular domain of the receptor, using a combination of VSSP and Montanide ISA 51 as adjuvants. We summarize the results obtained with this vaccine in both the preclinical and clinical settings, emphasizing the importance of the induction of both humoral and cellular responses for the success of cancer vaccines, as safe therapeutic alternatives for the treatment of cancer.



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