The glycophosphatidylinositol anchor oppositely affects unfolding and refolding of alkaline phosphatase

Regarding the world wide success of artificial chaperone-assisted protein refolding technique and based on its well worked-out mechanism, it is anticipated that the lipid moieties of glycosylphosphatidylinositol (GPI) group, which is present in some membrane proteins, might interfere with the capturing step of the technique. To find an answer, we evaluated the chemical denaturation and also the refolding behavior of insoluble and soluble alkaline phosohatase (ALP), with or without GPI group, respectively. The results indicated that the presence of GPI in the enzyme increased the stability of the protein against chemical denaturation while it decreased its refolding yield by the artificial chaperone refolding technique. The lower refolding yield, compared to soluble ALP (sALP), might be due to a less efficient stripping step caused by new interactions imparted to the refolding elements of the system especially those among the hydrophobic tails of GPI and the capturing agent of the technique. These new interactions will interrupt the kinetics of detergent stripping from the captured molecules by the stripping agent (i.e., cyclodextrins). This situation will lead to higher intermolecular hydrophobic interactions among the refolding protein intermediates leading to their higher misfolding and aggregation.     

Analysis of RAS gene mutations in cytogenetically normal de novo acute myeloid leukemia patients reveals some novel alterations

Rat sarcoma gene (RAS) holds great importance in pathogenesis of acute myeloid leukemia (AML). The activated mutations in Neuroblastoma rat sarcoma viral oncogene homolog (NRAS) and Kirsten rat sarcoma viral oncogene homolog (KRAS) confers proliferative and survival signals, deliberating numerous effects on overall survival and progression free survival in AML patients. In this study thirty one (31) blood samples of adult newly diagnosed AML patients were collected to identify possible incidence of mutations through amplification of KRAS (exon 1 and 2) and NRAS gene (exon 1 and 2) using polymerase chain reaction (PCR). Amplicons were then subjected to sequencing and were analyzed through Geneious Prime 2019. Five of thirty one (16.12%) patients had altered sites in either NRAS or KRAS. The NRAS mutations were observed in three AML patients (N = 3, 9.67%). A novel missense mutation NRAS-I36R (239 T > G) representing a substitution of single nucleotide basepair found in NRAS exon 1 while exon 2 was detected with heterozygous mutation NRAS-E63X (318G > T) and insertion (A), resulting in frameshift of the amino acid sequence and insertion of two nucleotide basepairs (TA) in two of the patients. KRAS mutations (N = 2, 6.45%) were found in exon 1 whereas no mutations in KRAS exon 2 were detected in our patient cohort. Mutation in KRAS Exon 1, KRAS-D30N (280G > A) was observed in two patients and one of them also had a novel heterozygous mutation KRAS-L16N (240G > C). In addition there was no statistically significant association of mutRAS gene of AML patients with several prognostic markers including age, gender, karyotyping, CD34 positivity, cytogenetic abnormalities, total leukocyte count, white blood cell count and French-American-British (FAB) classification. However, the presence of mutRAS gene were strongly associated (p = 0.001) with increased percentage of bone marrow blasts. The prevalence of mutations in correlation with clinical and hematological parameter is useful for risk stratification in AML patients.     

Effect of Flexible and Rigid Linkers on Biological Activity of Recombinant Tetramer Variants of S3 Antimicrobial Peptide

International Journal of Peptide Research and Therapeutics - Antimicrobial peptides (AMPs) mainly introduced as a new generation of antibiotics, could be used for broad medical and biotechnological...     

The Effect of Temperature on the Toxicity of Insecticides against Musca domestica L.: Implications for the Effective Management of Diarrhea

Background

Diarrhea is an important cause of childhood mortality in developing countries like Pakistan because of unhygienic conditions, lack of awareness, and unwise use of preventive measures. Mechanical transmission of diarrheal pathogens by house flies, Musca domestica, is believed as the most effective route of diarrhea transmission. Although the use of insecticides as a preventive measure is common worldwide for the management of house flies, success of the measure could be compromised by the prevailing environmental temperature since it significantly affects toxicity of insecticides and thus their efficacy. Peaks of the house fly density and diarrheal cases are usually coincided and season specific, yet little is known about the season specific use of insecticides.

Methodology/Principal Findings

To determine the temperature-toxicity relationship in house flies, the effect of post-bioassays temperature (range, 20–34°C) on the toxicity of seven insecticides from organophosphate (chlorpyrifos, profenofos), pyrethroid (cypermethrin, deltamethrin) and new chemical (emamectin benzoate, fipronil, spinosad) classes was evaluated by using a feeding bioassay method. From 20–34°C, the toxicities of chlorpyrifos, profenofos, emamectin and fipronil increased 2.10, 2.93, 2.40 and 3.82 fold (i.e. positive temperature coefficient), respectively. Whereas, the toxicities of cypermethrin, deltamethrin and spinosad decreased 2.21, 2.42 and 3.16 fold (i.e. negative temperature coefficient), respectively.

Conclusion/Significance

These findings suggest that for the reduction in diarrheal cases, house flies should be controlled with insecticides according to the prevailing environmental temperature. Insecticides with a positive temperature coefficient may serve as potential candidates in controlling house flies and diarrhea epidemics in hot season and vice versa.     

Dihydro-CDDO-trifluoroethyl amide suppresses inflammatory responses in macrophages via activation of Nrf2

Nuclear factor erythroid 2-related factor (Nrf2) is the major regulator of cellular defenses against various pathological stresses in a variety of organ systems, thus Nrf2 has evolved to be an attractive drug target for the treatment and/or prevention of human disease. Several synthetic oleanolic triterpenoids including dihydro-CDDO-trifluoroethyl amide (dh404) appear to be potent activators of Nrf2 and exhibit chemopreventive promises in multiple disease models. While the pharmacological efficacy of Nrf2 activators may be dependent on the nature of Nrf2 activation in specific cell types of target organs, the precise role of Nrf2 in mediating biological effects of Nrf2 activating compounds in various cell types remains to be further explored. Herein we report a unique and Nrf2-dependent anti-inflammatory profile of dh404 in inflamed macrophages. In lipopolysaccharide (LPS)-inflamed RAW264.7 macrophages, dh404 dramatically suppressed the expression of pro-inflammatory cytokines including inducible nitric oxide synthase (iNOS), monocyte chemotactic protein-1 (MCP-1), and macrophage inflammatory protein-1 beta (MIP-1β), while minimally regulating the expression of interleulin-6 (IL-6), IL-1β, and tumor necrosis factor alpha (TNFα). Dh404 potently activated Nrf2 signaling; however, it did not affect LPS-induced NF-κB activity. Dh404 did not interrupt the interaction of Nrf2 with its endogenous inhibitor Kelch-like ECH associating protein 1 (Keap1) in macrophages. Moreover, knockout of Nrf2 blocked the dh404-induced anti-inflammatory responses in LPS-inflamed macrophages. These results demonstrated that dh404 suppresses pro-inflammatory responses in macrophages via an activation of Nrf2 independently of Keap1 and NF-κB, suggesting a unique therapeutic potential of dh404 for specific targeting a Nrf2-mediated resolution of inflammation.     

Penicillium oxalicum directed systemic resistance in tomato against Alternaria alternata

Enhanced yield of tomato has ever been an important issue due to its nutritional value and various dietary consumption forms. But, efficient yield increase can never be achieved without using environmentally safe means e.g. innate resistance. In present study, tomato innate antifungal resistance has been boosted up using Penicillium oxalicum, and then various aspects of resistance modulation have been explored in details. Two tomato varieties of differential antifungal resistance (Dinaar and Red Tara) were treated with six P. oxalicum strains which screened the best inducer strain (Pn 5); which remarkably controlled disease incidence (DI) of Alternaria alternata. Inducer was not only responsible for almost two times production of phenolics, alkaloids and terpenoids in Red Tara, but it also non-significantly triggered same biochemicals in Dinaar. Hemicellulose showed only 40 % increase in variety of least antifungal resistance. During quantification assays of peroxidase (POD), phenyl ammonia lyase and polyphenol oxidase, more or less the same doubling trend was recorded in susceptible variety, while only POD had significant enhancement in resistant variety under the influence of fungal inducer. It was also recorded that inducer not only modulated quantity of enzyme (glucanase), but its isozyme package was also altered. Colorimetric quantifications of lignin, cellulose and pectins proved that biotic inducer strengthened the physical structure of plant cells by increasing these contents from 30 to 120 %. The above investigation collectively comes with the recommendation of an efficient and environmentally safe inducer (P. oxalicum); which, can be used to control fungal pathogens.     

Sequential metronidazole-furazolidone or clarithromycin-furazolidone compared to clarithromycin-based quadruple regimens for the eradication of Helicobacter pylori in peptic ulcer disease: a double-blind randomized controlled trial

Background: Furazolidone is a much cheaper drug with a very low resistance against Helicobacter pylori compared to clarithromycin. We aim to evaluate safety and efficacy of a sequential furazolidone‐based regimen versus clarithromycin‐based therapy in H. pylori eradication for ulcer disease. Materials: Patients with proven peptic ulcer or duodenitis were randomized into three groups: OAB‐M‐F; metronidazole (M) (500 mg bid) for the first 5 days, followed by furazolidone (F) (200 mg bid) for the second 5 days; OAC‐P; clarithromycin (C) (500 mg bid) for 10 days; and OAB‐C‐F; clarithromycin (500 mg bid) for the first 5 days and furazolidone (200 mg bid) for the second 5 days. All groups received omeprazole (O) (20 mg bid) and amoxicillin (A) (1 g bid). Groups OAB‐M‐F and OAB‐C‐F were also given bismuth subcitrate (B) (240 mg bid), whereas a placebo (P) was given to group OAC‐P. Adverse events were scored and recorded. Two months after treatment, a C¹³‐urea breath test was performed. Results: Three hundred and ten patients were enrolled and 92 (OAB‐M‐F), 95 (OAC‐P), and 98 (OAB‐C‐F) completed the study. The intention‐to‐treat eradication rates were 78.5% (95% CI = 69–85), 81.1% (95% CI = 73–88), and 82% (95% CI = 74–89), and per‐protocol eradication rates were 91.3% (95% CI = 83–96), 90.4% (95% CI = 82–95), and 88.7% (95% CI = 81–94), for group OAB‐M‐F, OAC‐P, and OAB‐C‐F, respectively. Eradication rate differences did not reach statistical significance. The most common adverse event, bad taste, occurred in all groups, but more frequently in groups OAC‐P (34%) and OAB‐C‐F (32%), than OAB‐M‐F (14%) (p < .05). Adverse symptoms score were 0.88 ± 2.05 in group OAB‐M‐F, 1.15 ± 1.40 in group OAC‐P, and 1.87 ± 1.62 in group OAB‐C‐F. Conclusion: Furazolidone can replace clarithromycin in H. pylori eradication regimens because of lack of development of resistance and very low cost.     

Glucose regulation of CDK7, a putative thiol related gene, in experimental diabetic nephropathy

We previously described the identification of the 3'end of an unknown gene CDK7 using differential display which appeared to be up-regulated in diabetic kidneys [R.A. Page, C.A. Morris, J.D. Williams, C.J. von Ruhland, A.N. Malik, Isolation of diabetes-associated kidney genes using differential display, Biochem. Biophys. Res. Commun. 232 (1997) 49-53]. Here we show that CDK7 is a putative thiol related gene which is regulated by glucose in human and rat renal cells. CDK7 mRNA increased by >threefold in cultured human mesangial cells grown in high glucose for 4 days. In the kidneys of the GK rat, a model of type II diabetes, CDK7 showed a steady age-related increase in mRNA, increasing to >sixfold in 40 week GK rats compared to normoglycemic age-matched Wistar rat kidneys, this increase correlates with progressive hyperglycemia. CDK7 mRNA is widely expressed, showing particularly high levels of expression in rat and human liver, and encodes a putative 338 amino acids highly conserved peptide with several conserved domains, including a cys-pro-arg-cys domain conserved in 15 diverse species which is similar to the catalytic centre of thioredoxin, suggesting a role in oxidative stress.     

阿克苏市5种常见绿化树种滞尘规律

绿化树种在截留沙尘、降低大气颗粒污染物浓度、改善城市生态环境等方面发挥着不可替代的作用。该文选取新疆南部典型绿洲城市——阿克苏市不同功能区的绿化树种, 用多重比较法对比分析了二球悬铃木(Platanus × acerifolia)、新疆杨(Populus alba var. pyramidalis)、圆冠榆(Ulmus densa)、天山梣(Fraxinus sogdiana)和垂柳(Salix babylonica) 5个树种叶片平均滞尘量随时间变化及不同高度叶片的滞尘能力, 探讨了阿克苏市主要绿化树种的滞尘规律, 得出以下结论: 不同绿化树种单位叶面积滞尘量差异显著, 差距在1.15-2.17倍之间, 绿化树种滞尘量随着时间延长而增加; 同一树种在城市不同功能区的滞尘能力不同: 工业区>交通枢纽区>居民区>清洁区; 不同高度的叶片, 其滞尘量在工业区和交通枢纽区差异显著: 高度1 m的叶片滞尘量>高度2 m的叶片滞尘量>高度4 m的叶片滞尘量。