Micro-quantitation of lipids in serum-free cell culture media: a critical aspect is the minimization of interference from medium components and chemical reagents

Lipids (fatty acids) at a concentration range of 10-100 microg/L are essential components included in most serum-free cell culture medium formulations. A gas chromatography/mass spectrometry (GC/MS) method for the micro-quantitation of lipids, determined as fatty acid methyl esters (FAMEs), in complex serum-free cell culture media was developed. The interference of derivatizing reagents, extraction solvents and medium additives in the micro-quantitation of lipids was also examined. The results show that the concentration of fatty acids such as palmitic and stearic acids detected in derivatizing reagents or extraction solvents was in the range of 10-230 microg/L. Tween-80, a surfactant and medium additive, produced nearly 20 FAMEs alone when methylated using a derivatizing agent. Moreover, the surfactant Pluronic F-68, a medium additive, interfered in the FAME recovery. Procedures, which include use of low volumetric ratio of reagent to medium and precipitation of the above surfactants, were developed to minimize background FAMEs to levels which do not significantly affect the quantitation of medium lipids and to diminish the interference caused by Pluronic F-68. Fatty acid concentrations in several complex serum-free culture media were quantitated by this method and were very close to the values indicated in their formulations.     

Association of laryngeal and nasopharyngeal tuberculosis: a case report

Introduction

To the best of our knowledge, the association of nasopharyngeal and laryngeal tuberculosis has never been described before in the literature. We report here a first observation.

Case presentation

We report the case of a 38-year-old Arab man who presented with an isolated hoarseness. Radiological and endoscopic examinations showed a thickening of the left lateral wall of his nasopharynx and the left vocal cord. Pathology revealed the diagnosis of tuberculosis of both localizations. He received a 6-month antituberculous chemotherapy with a satisfying uneventful evolution.

Conclusions

Tuberculosis should be considered in the differential diagnosis of soft tissue masses of the head and neck, particularly when the imaging findings and clinical presentation are atypical. The diagnosis of tuberculosis is mainly based on histopathological and/or bacteriological examination.     

An integrative approach to identify hexaploid wheat miRNAome associated with development and tolerance to abiotic stress

Background

Wheat is a major staple crop with broad adaptability to a wide range of environmental conditions. This adaptability involves several stress and developmentally responsive genes, in which microRNAs (miRNAs) have emerged as important regulatory factors. However, the currently used approaches to identify miRNAs in this polyploid complex system focus on conserved and highly expressed miRNAs avoiding regularly those that are often lineage-specific, condition-specific, or appeared recently in evolution. In addition, many environmental and biological factors affecting miRNA expression were not yet considered, resulting still in an incomplete repertoire of wheat miRNAs.

Results

We developed a conservation-independent technique based on an integrative approach that combines machine learning, bioinformatic tools, biological insights of known miRNA expression profiles and universal criteria of plant miRNAs to identify miRNAs with more confidence. The developed pipeline can potentially identify novel wheat miRNAs that share features common to several species or that are species specific or clade specific. It allowed the discovery of 199 miRNA candidates associated with different abiotic stresses and development stages. We also highlight from the raw data 267 miRNAs conserved with 43 miRBase families. The predicted miRNAs are highly associated with abiotic stress responses, tolerance and development. GO enrichment analysis showed that they may play biological and physiological roles associated with cold, salt and aluminum (Al) through auxin signaling pathways, regulation of gene expression, ubiquitination, transport, carbohydrates, gibberellins, lipid, glutathione and secondary metabolism, photosynthesis, as well as floral transition and flowering.

Conclusion

This approach provides a broad repertoire of hexaploid wheat miRNAs associated with abiotic stress responses, tolerance and development. These valuable resources of expressed wheat miRNAs will help in elucidating the regulatory mechanisms involved in freezing and Al responses and tolerance mechanisms as well as for development and flowering. In the long term, it may help in breeding stress tolerant plants.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1490-8) contains supplementary material, which is available to authorized users.     

Fetal microchimerism in kidney biopsies of lupus nephritis patients may be associated with a beneficial effect

IntroductionMicrochimeric male fetal cells (MFCs) have been associated with systemic lupus erythematosus, and published studies have further correlated MFC with lupus nephritis (LN). In the present study, we evaluated the frequency of MFC in the renal tissue of patients with LN.MethodsTwenty-seven renal biopsies were evaluated: Fourteen were from women with clinical and laboratory findings of LN, and thirteen were from controls. Genomic DNA was extracted from kidney biopsies, and the male fetal DNA was quantified using real-time quantitative polymerase chain reactions for the detection of specific Y chromosome sequences.ResultsMFCs were detected in 9 (64%) of 14 of patients with LN, whereas no MFCs were found in the control group (P = 0.0006). No differences in pregnancy history were found between patients with LN and the control group. Significantly higher amounts of MFCs were found in patients with LN with serum creatinine ≤1.5 mg/dl. Furthermore, women with MFCs had significantly better renal function at the time of biopsy (P = 0.03). In contrast, patients with LN without MFCs presented with more severe forms of glomerulonephritis (World Health Organization class IV = 60% and class V = 40%).ConclusionsOur data indicate a high prevalence of MFCs in renal biopsy specimens from women with LN, suggesting a role for MFCs in the etiology of LN. The present report also provides some evidence that MFCs could have a beneficial effect in this disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0615-4) contains supplementary material, which is available to authorized users.     

USP18 lack in microglia causes destructive interferonopathy of the mouse brain

Microglia are tissue macrophages of the central nervous system (CNS) that control tissue homeostasis. Microglia dysregulation is thought to be causal for a group of neuropsychiatric, neurodegenerative and neuroinflammatory diseases, called “microgliopathies”. However, how the intracellular stimulation machinery in microglia is controlled is poorly understood. Here, we identified the ubiquitin‐specific protease (Usp) 18 in white matter microglia that essentially contributes to microglial quiescence. We further found that microglial Usp18 negatively regulates the activation of Stat1 and concomitant induction of interferon‐induced genes, thereby terminating IFN signaling. The Usp18‐mediated control was independent from its catalytic activity but instead required the interaction with Ifnar2. Additionally, the absence of Ifnar1 restored microglial activation, indicating a tonic IFN signal which needs to be negatively controlled by Usp18 under non‐diseased conditions. These results identify Usp18 as a critical negative regulator of microglia activation and demonstrate a protective role of Usp18 for microglia function by regulating the Ifnar pathway. The findings establish Usp18 as a new molecule preventing destructive microgliopathy.     

Study of Thermal Decomposition of Li1‐x(Ni1/3Mn1/3Co1/3)0.9O2 Using In‐Situ High‐Energy X‐Ray Diffraction

Safety has been a major technological concern hindering the deployment of lithium‐ion batteries for automobile applications. We investigated the decomposition mechanism of delithiated cathode materials at thermal abuse conditions using Li_1.1[Ni_1/3Mn_1/3Co_1/3]_0.9O₂ as a model cathode material. An in‐situ high‐energy X‐ray diffraction technique was established as an alternative to conventional thermal analysis techniques like differential scanning calorimetry and accelerating rate calorimetry. The X‐ray diffraction data revealed that the thermal decomposition pathway of delithiated Li_1‐x[Ni_1/3Mn_1/3Co_1/3]_0.9O₂ strongly depended on the exposed chemical environment, like solvents and lithium salts. A phase transformation of dry delithiated Li_1‐x[Ni_1/3Mn_1/3Co_1/3]_0.9O₂ was observed at about 278 °C, and its onset temperature was reduced to about 197°C with the presence of the electrolyte. It is suggested that the reduction in thermal stability is possibly related to proton intercalation into the delithiated material.     

Evaluation of APOE polymorphisms and the risk for age-related macular degeneration in a Southeastern Brazilian population

This study aimed to evaluate the role of APOE polymorphisms (rs429358 and rs7412) in the risk of age-related macular degeneration in a sample of the Southeastern Brazilian population. Seven hundred and five unrelated individuals were analyzed, 334 with age-related macular degeneration (case group), and 371 without the disease (control group). In the case group, patients were further stratified according to disease phenotypes, divided into dry and wet age-related macular degeneration, and non-advanced and advanced age-related macular degeneration. APOE polymorphisms (rs429358 and rs7412) were evaluated through polymerase chain reaction and direct sequencing. In the comparison of cases vs. controls, none of the associations reached statistical significance, considering the Bonferroni-adjusted P-value, although there was a suggestive protection for the E3/E4 genotype (OR = 0.626; P-value = 0.037) and E4 carriers (OR = 0.6515; P-value = 0.047). Statistically significant protection for both the E3/E4 genotype and E4 carriers was observed in the comparisons: advanced age-related macular degeneration vs. controls (OR = 0.3665, P-value = 0.491 × 10⁻³ and OR = 0.4031, P-value = 0.814 × 10⁻³, respectively), advanced age-related macular degeneration vs. non-advanced age-related macular degeneration (OR = 0.2529, P-value = 0.659 × 10⁻⁴ and OR = 0.2692, P-value = 0.631 × 10⁻⁴, respectively). In the comparison of wet age-related macular degeneration vs. control, protection was statistically significant only for E3/E4 (OR = 0.4052, P-value = 0.001). None of the comparisons demonstrated any significant association for E2 genotypes or E2 carriers in age-related macular degeneration risk in this study. Findings suggest a protective role of the E4 haplotype in the APOE gene in the risk for advanced and wet forms of age-related macular degeneration, in a sample of the Brazilian population. To our knowledge, this is the first Brazilian study to show the association between APOE polymorphisms and age-related macular degeneration.     

1H, 13C, and 15N resonance assignment of a 179 residue fragment of hepatitis C virus non-structural protein 5A

Non-structural protein 5A (NS5A) plays an important role in the life cycle of hepatitis C virus. This proline-rich phosphoprotein is organized into three domains. Besides its role in virus replication and virus assembly, NS5A is involved in a variety of cellular regulation processes. Recent studies on domain 2 and 3 revealed that both belong to the class of intrinsically disordered proteins as they adopt a natively unfolded state. In particular, domain 2 together with its vicinal regions is responsible for NS5A’s multiple interactions with other proteins necessary for virus persistence. The low chemical shift dispersion observed for instrinsically disordered proteins presents a challenge for NMR spectroscopy. Here we report sequential resonance assignment of a 179-residue fragment of NS5A, comprising the entire domain 2, using a set of sensitivity and resolution optimized 3D correlation experiments, as well as amino-acid-type editing in ¹H-¹⁵N correlation spectra. Our assignment reveals the presence of several segments with high propensity to form α-helical structure that may be of importance to the function of this protein fragment as a versatile interaction platform.     

Chitooligosaccharide inhibits RANKL-induced osteoclastogenesis and ligation-induced periodontitis by suppressing MAPK/ c-fos/NFATC1 signaling

Considering the high rate of osteoclast-related diseases worldwide, research targeting osteoclast formation/function is crucial. In vitro, we demonstrated that chitooligosaccharide (CS) dramatically inhibited osteoclastogenesis as well as osteoclast function dose-dependently. CS suppressed osteoclast-specific genes expression during osteoclastogenesis. Furthermore, we found that CS attenuated receptor activator of nuclear factor kappa B ligand (RANKL)-mediated mitogen-activated protein kinase (MAPK) pathway involving p38, erk1/2, and jnk, leading to the reduced expression of c-fos and nuclear factor of activated T cells c1 (NFATc1) during osteoclast differentiation. In vivo, we found CS protected rats from periodontitis-induced alveolar bone loss by micro-computerized tomography and histological analysis. Overall, CS inhibited RANKL-induced osteoclastogenesis and ligature-induced rat periodontitis model, probably by suppressing the MAPK/c-fos/NFATc1 signaling pathway. Therefore, CS may be a safe and promising treatment for osteoclast-related diseases.