Trypsin-like Enzymes Research Articles

PH influences the profiles of midgut extracts in Cnaphalocrocis medinalis (Guenée) and its degradation of activated Cry toxins

Midgut extracts play crucial roles in food digestion and detoxification. We evaluated the effect of pH on the profiles of the midgut extracts in rice leaffolder, Cnaphalocrocis medinalis and the degradation of activated Bt-toxins by the midgut extracts under different pH conditions. Total protease activity increased slightly with the increase with the simulated pH in the midgut extracts and the maximal protease activity was observed at pH 10.5, while an upward trend was observed as the pH of reaction buffer increased. Activity of chymotrypsin-like enzymes increased with pH, both in the buffer and midgut extracts, while the activity of trypsin-like enzyme was unaffected. Degradation of the activated Cry2A by the midgut extracts enhanced as the pH increased. Cry2A was fully degraded into smaller segments at pH 9.0–10.5. Activated Cry1C protein at pH 9.0–10.5 was partially degraded by the midgut extracts. Activated Cry1Aa and Cry1Ac were partially degraded into fragments by the midgut extracts at high pH. These results will facilitate our further understanding of the interactions between C. medinalis and the Cry toxin.

Traffic-derived air pollution compromises skin barrier function and stratum corneum redox status: A population study.

Since air pollution is only one of many environmental stressors that can affect skin, it has been challenging to identify skin appearance or functional features profoundly affected by chronic exposure to traffic-derived air pollution. The current population study focused on taxi drivers working in urban and rural areas in order to take advantage of difference in occupational exposure. The skin conditions of 100 middle-aged male taxi drivers from urban Shanghai and 66 from rural Chongming were measured with facial tape strips were collected for biomarker analyses. Trans-epidermal water loss (TEWL) values before and after tape stripping were considerably higher in urban taxi drivers from Shanghai. Contrary to previous studies, there was no apparent detrimental effect on skin wrinkle or pigmentation from traffic pollution, which might be attributed to the higher than general public level of photo-exposure in this population. At the same time, pollution exposure especially the heavy traffic pollution exposure was found to associate with lower stratum corneum trypsin-like enzyme activity (SCTE), reduced catalase activity and total antioxidant capacity (TAOC) in tape strips. The evidence suggests that traffic-derived air pollution could deteriorate skin's physical and antioxidant barrier, whereas factors like photo-exposure can be overwhelming against appearance aging. Therefore, in addition to photoprotection, skin barrier care should be considered for people with high air pollution exposure.

Clotting factors: Clinical biochemistry and their roles as plasma enzymes.

The purpose of this review is to describe structure and function of the multiple proteins of the coagulation system and their subcomponent domains. Coagulation is the process by which flowing liquid blood plasma is converted to a soft, viscous gel entrapping the cellular components of blood including red cells and platelets and thereby preventing extravasation of blood. This process is triggered by the minimal proteolysis of plasma fibrinogen. This transforms the latter to sticky fibrin monomers which polymerize into a network. The proteolysis of fibrinogen is a function of the trypsin-like enzyme termed thrombin. Thrombin in turn is activated by a cascade of trypsin-like enzymes that we term coagulation factors. In this review we examine the mechanics of the coagulation cascade with a view to the structure-function relationships of the proteins. We also note that two of the factors have no trypsin like protease domain but are essential cofactors or catalysts for the proteases. This review does not discuss the major role of platelets except to highlight their membrane function with respect to the factors. Coagulation testing is a major part of routine diagnostic clinical pathology. Testing is performed on specimens from individuals either with bleeding or with thrombotic disorders and those on anticoagulant medications. We examine the basic in-vitro laboratory coagulation tests and review the literature comparing the in vitro and in vivo processes. In vitro clinical testing typically utilizes plasma specimens and non-physiological or supraphysiological activators. Because the review focuses on coagulation factor structure, a brief overview of the evolutionary origins of the coagulation system is included.

Cromatografía de interacción hidrofóbica como método de separación de proteasas alcalinas de vísceras de Scomberomorus sierra

Este estudio se enfocó en recuperar proteasas alcalinas de vísceras de Scomberomorus sierra mediante cromatografía de interacción hidrofóbica. Tres proteasas alcalinas se lograron separar parcialmente usando esta técnica cromatográfica; dos de ellas con pesos moleculares de 19 y 31 kDa fueron identificadas como enzimas tipo tripsina de acuerdo a ensayos de inhibición. La proteasa alcalina con peso molecular de 31 kDa, única enzima aislada, fue purificada bajo las siguientes condiciones cromatográficas: sulfato de amonio l3% (p/v) y etilenglicol al 27% (p/v); esta enzima mostró actividad máxima a pH 9 – 10 y 50 – 60 °C y fue fuertemente inhibida por el inhibidor de tripsina de soya (SBTI) como por el inhibidor de tripsina porcina (TPI). Una tercera proteasa alcalina con peso molecular de 20 kDa fue parcialmente separada e inhibida por tosil fenilalanil clorometil cetona (TPCK), la cual mostró actividad óptima a pH 9 – 11 y 60 °C. Estos resultados muestran que las vísceras de Scomberomorus sierra podrían ser de utilidad como fuente de proteasas.

ONTOGENETIC CHANGES IN THE ACTIVITY OF TRYPSIN-LIKE ENZYMES IN INDIVIDUALS OF THE LABORATORY POPULATION OF DROSOPHILA MELANOGASTER AND DROSOPHILA VIRILIS

Introduction. The ontogenetic variation of body mass index and activity of trypsin-like enzymes in individuals of laboratory populations of two species of fruit fly: Drosophila melanogaster and Drosophila virilis were studied.The aim of the work was to investigate the level of fluctuation of trypsin-peptide hydrolase activity at different stages of ontogenesis in separate individuals of the laboratory populations of Drosophila virilis and Drosophila melanogaster and to compare the activity indicators of the studied species.Methods. The material of the study was the 3-day-old larvae, pupae and adults of two Drosophila species that were cultivated under standard conditions. In individually prepared homogenates, the total activity of trypsin-like enzymes was determined using the specific substrate N-benzoyl-DL-arginine-p-nitroanilide hydrochloride (BAPNA). The enzymatic hydrolysis of BAPNA was carried out in an alkaline medium in the presence of peptide hydrolases. The dynamics of optical density (ΔE) was determined at λ = 382.5 nm. The calculation of the relative activity of the enzymes was carried out on the basis of the extinction values obtained. The specific activity was found by the formula. The obtained primary data were processed statistically and presented in the form of variation curves and histograms.Results and conclusion. The variation curves of the body mass for larvae, pupae and imago were built by the data of separate individuals. The ontogenetic changes of the individual relative and specific activity of trypsin-like enzymes at the population level were determined. The average body mass index and activity of trypsin-like enzymes for each stage of post-embryonic development of Drosophila were calculated. The ranges of variation of the studied parameters under the stationary conditions of Drosophila cultivation were determined. It was determined that the highest indices of the body weight of individuals and their proteolytic activity (by the data of species melanogaster) coincide with the larval phase of the development. Possible causes of individual differences in the expression of the activity of trypsin-like enzymes in Drosophila are discussed.

Chymotrypsin- and trypsin-like activities secreted by the multidrug-resistant yeasts forming the Candida haemulonii complex.

Candida haemulonii complex (C. haemulonii, C. haemulonii var. vulnera and C. duobushaemulonii) consists of emergent multidrug-resistant pathogens that cause bloodstream and deep-seated infections. However, little is known about their virulence factors. Herein, we evaluated the presence of extracellular serine peptidases in this fungal complex. Serine peptidase activity was measured by spectrophotometry using chromogenic peptide substrates to the S1 family. Chymotrypsin-, trypsin- and elastase-like activities were detected in all fungal isolates. Since higher chymotrypsin- and trypsin-like activities were observed from the cleavage of N-succinyl-Ala-Ala-Pro-Phe-pNa and N-benzoyl-Phe-Val-Arg-pNa, respectively, these substrates were selected for further experiments. Overall, pHs 7.0 and 9.0 were those in which higher chymotrypsin- and trypsin-like activities were observed, respectively, displaying higher hydrolytic activities at 37-45°C. Additionally, the serine peptidases produced by C. haemulonii complex were inhibited by PMSF and AEBSF in a typically concentration-dependent manner. Although the Michaelis constant (Km) values obtained for chymotrypsin-like peptidases were similar, greater differences were observed for trypsin-like enzymes secreted by the different fungal isolates. This is the first time that peptidases belonging to the S1 family are described in the C. haemulonii species complex. Thus, these data open the doors for more detailed studies into potential roles of these peptidases in fungal virulence.

Characteristics of hemostasis system and activity of trypsin-like blood enzymes in comorbid patients with chronic obstructive pulmonary disease and hypertension.

This work was aimed at studying the activity of the hemostasis system and trypsin-like blood enzymes (TLE) in patients with chronic obstructive pulmonary disease (COPD) and hypertension (H), depending on anthropometric, clinical features and smoking. The study included 87 patients. I group included 39 patients with COPD A – D, II-IV by GOLD and conco­mitant with H I-II stage, II group – 38 patients with H I - II stage, and K group – 10 apparently healthy persons. The study was conducted on the background of the use of standard basic therapy by patients from the 1st and 2nd groups in a stable period of disease. The degree of thrombocyte (tr) adhesion in I and II groups of patients was higher than in the K group. Both adhesive activity and the amount of tr in the I group was higher than in the II group. With positive status of smoking and increasing nicotine addiction in comorbid patients with COPD and H, the adhesive activity of tr increased. The level of the procoagulantive parameters of the plasma part of hemostasis in the two studied groups was not statistically different, but was higher than in the K group. Increased BMR and dyspnoea by the mMRS scale in group with COPD and H and increased age of patients with H led to the increase in the activity of plasma coagulation factors. In I and II groups, the increase in blood TLE was observed, which increased with the body weight, while in comorbid patients in the subgroup with FEV1≥50%, the incidence of COPD exacerbation additionaly effects the increase of TLE. In I group correlation between reduction of FEV1 with the decrease of TLE was revealed. In patients with COPD and AH activity of thrombocyte and plasma hemostasis, as well as trypsin-like blood enzymes, increases. Smoking, body weight gain and incidence of COPD exacerbation contribute to increased prothrombotic potential.

High precision protein functional site detection using 3D convolutional neural networks.

MotivationAccurate annotation of protein functions is fundamental for understanding molecular and cellular physiology. Data-driven methods hold promise for systematically deriving rules underlying the relationship between protein structure and function. However, the choice of protein structural representation is critical. Pre-defined biochemical features emphasize certain aspects of protein properties while ignoring others, and therefore may fail to capture critical information in complex protein sites.ResultsIn this paper, we present a general framework that applies 3D convolutional neural networks (3DCNNs) to structure-based protein functional site detection. The framework can extract task-dependent features automatically from the raw atom distributions. We benchmarked our method against other methods and demonstrate better or comparable performance for site detection. Our deep 3DCNNs achieved an average recall of 0.955 at a precision threshold of 0.99 on PROSITE families, detected 98.89 and 92.88% of nitric oxide synthase and TRYPSIN-like enzyme sites in Catalytic Site Atlas, and showed good performance on challenging cases where sequence motifs are absent but a function is known to exist. Finally, we inspected the individual contributions of each atom to the classification decisions and show that our models successfully recapitulate known 3D features within protein functional sites.Availability and implementationThe 3DCNN models described in this paper are available at https://simtk.org/projects/fscnn.Supplementary information Supplementary data are available at Bioinformatics online.

Crystal structure of a novel Kunitz type inhibitor, alocasin with anti-Aedes aegypti activity targeting midgut proteases.

The pesticidal properties of many Kunitz-type inhibitors have been reported previously; however, the mechanism of action is not well established. In this study, the activity of alocasin against Aedes aegypti is demonstrated and the structure-activity relationship of this Kunitz-type inhibitor is explained through X-ray structure analyses. Alocasin was purified from mature rhizomes of Alocasia as a single polypeptide chain of ∼ 20 kDa. The structure at 2.5 Å resolution revealed a Kunitz-type fold, but variation in the loop regions makes this structure unique; one loop with a single disulfide bridge is replaced by a long loop with two bridges. Alignment of homologous sequences revealed that this long loop contains a conserved Arg residue and modeling studies showed interaction with the catalytic Ser residue of trypsin-like enzymes. The anti-Aedes aegypti activity of alocasin is examined and discussed in detail. The in vitro activity of alocasin against midgut proteases of Aedes aegypti showed profound inhibition. Further, morphological changes in larvae upon treatment with alocasin revealed its activity against Ae. aegypti. Docking studies of alocasin with trypsin (5G1), a midgut protease involved in the development cycle and blood meal digestion, illustrated its insecticidal activity. The three-dimensional structure of alocasin was determined and its structure-function relationship established for its anti Ae. aegypti activity. © 2018 Society of Chemical Industry.

Abstract 2679: Cyanobacterial trypsin-3 inhibitor inhibits prostate cancer cell invasion

Abstract Trypsin-3 is a highly active protease that has recently been identified as a potential therapeutic target for the reduction of tumor growth and metastasis in prostate, breast and pancreatic cancers. Current trypsin inhibitors typically inhibit a broad range of different trypsin-like enzymes. Thus, novel approaches to identify trypsin-3 selective inhibitors are needed. Cyanobacteria produce a vast diversity of natural products with complex chemical structures many of which are potent protease inhibitors. We screened extracts of 140 cyanobacteria strains and discovered numerous strains showing selectivity towards trypsin-2 and -3 inhibition. We isolated a complex glycopeptide from one of these strains, which selectively inhibited human trypsin-2 and -3 with IC50 values of about 100 nM, while trypsin-1 was not inhibited. Importantly, we also found that this peptide inhibited invasion of aggressive and metastatic PC-3M prostate cancer cells though ECM preparation, while it did not affect the proliferation of the cells. Our results suggest that microbial natural products may offer a viable alternative source of potent and selective trypsin-3 inhibitors. Such inhibitors may be suitable, after further development, for targeting the mechanisms associated with the invasion and metastatic dissemination of cancer cells, i.e., for treatment of aggressive cancers. Citation Format: Hannu Koistinen, Matti Wahlsten, Muhammad N. Ahmed, Kaarina Sivonen, Matthias Nees, Ulf-Håkan Stenman, David P. Fewer. Cyanobacterial trypsin-3 inhibitor inhibits prostate cancer cell invasion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2679.

Effects of protease inhibitors on the activities of midgut proteases in Callosobruchus chinensis (Linnaeus) larvae.

To clarify the effects of protease inhibitors on the activities of midgut proteases in Callosobruchus chinensis (L.) larvae, the inhibitory effects of four kinds of protease inhibitors on the activities of midgut proteases of C. chinensis larvae were examined in vitro and in feeding conditions with indoor artificial insect inoculation. The activities of total protease, trypsin-like enzyme and chymotrypsin-like enzyme in the midgut of C. chinensis larvae fed on artificial mung bean that contained different contents of mung bean types in inhibitor (MBTI) were examined. The results showed that those four protease inhibitors had significant inhibitory effects on the activities of total protease, trypsin-like enzyme and chymotrypsin-like enzyme in C. chinensis larvae. The inhibitory effect was more significant when the concentration was higher. Among those inhibitors, the inhibitory effect of 20 μg·mL-1 MBTI on three kinds of enzyme activities was the strongest, with reduction of 62.5%, 41.2% and 38.7%, respectively. Ovomucoid inhibitor (OI) had the lowest inhibitory effect. The activities of three enzymes in the midgut were also inhibited by C. chinensis larvae fed with artificial mung bean containing different inhibitors. The activities of three enzymes increased with the prolongation of the instar after feeding, but they were significantly lower than that in control. The inhibitory effect of MBTI was the strongest. The inhibitory effect on the activities of total protease and trypsin-like enzyme was gradually enhanced with the increases of MBTI contents when C. chinensis larvae were fed with artificial mung bean with different contents MBTI. The inhibitory effect on chymotrypsin-like enzyme activity was not significant. When the content of MBTI was up to 20%, the activity of chymotrypsin-like enzyme was obviously inhibited.

Culex pipiens sperm motility is initiated by a trypsin-like protease from male accessory glands.

In most animals, sperm are stored in a quiescent state in the male reproductive tract and only initiate motility when released into either the female reproductive tract, or, in the case of broadcast spawners, the external environment. Male accessory gland secretions transferred into the female reproductive tract may provide factors that modulate sperm viability and storage, or aid in sperm competition, as well as activate sperm motility. In several insects, serine proteases have been implicated in activating sperm motility. Our previous studies have shown that, in Culex quinquefasciatus, either a male accessory gland extract or purified trypsin is sufficient to initiate sperm motility in vitro. The objective of this study was to identify and characterize trypsin-like enzymes produced in the Culex male accessory glands. Mass spectrometry was used to analyze accessory gland proteins and this preliminary proteomic analysis identified 4 trypsin-like proteases (trypsin, trypsin4, and two trypsin7 isoforms). When measured with the chromogenic trypsin substrate Na -benzoyl-L-arginine-ethyl-ester-hydrochloride (BAEE), trypsin-like protease activity in the accessory glands was robust, with a pH optimum of 8. The pH range for the Culex trypsin activity was substantially narrower than a mammalian homologue (porcine pancreatic trypsin). A soybean trypsin inhibitor (SBTI) -agarose affinity column was used to independently identify trypsin-like accessory gland proteins. Several proteins were enriched in the eluate, as detected by silver staining of SDS-PAGE gels. Taken together, these data demonstrate the presence of trypsin-like activity and several trypsin-like proteins in the Culex male accessory glands.

Unexpected Specificity of a Trypsin-like Enzyme

In this issue of Structure, Stach etal. (2018) describe the properties of SplE, a trypsin-like enzyme from Staphylococcus aureus. They report, on the basis of biochemical and structural studies, the unusual specificity requiring the presence of histidine in the P1 subsite of its substrate.

Binding targets of termiticidal lectins from the bark and leaf of Myracrodruon urundeuva in the gut of Nasutitermes corniger workers

Lectins, carbohydrate-binding proteins, from the bark (MuBL) and leaf (MuLL) of Myracrodruon urundeuva are termiticidal agents against Nasutitermes corniger workers and have been shown to induce oxidative stress and cell death in the midgut of these insects. In this study, we investigated the binding targets of MuBL and MuLL in the gut of N. corniger workers by determining the effects of these lectins on the activity of digestive enzymes. In addition, we used mass spectrometry to identify peptides from gut proteins that adsorbed to MuBL-Sepharose and MuLL-Sepharose columns. Exoglucanase activity was neutralized in the presence of MuBL and stimulated by MuLL. α-l-Arabinofuranosidase activity was not affected by MuBL but was inhibited by MuLL. Both lectins stimulated α-amylase activity and inhibited protease and trypsin-like activities. Peptides with homology to apolipophorin, trypsin-like enzyme, and ABC transporter substrate-binding protein were detected from proteins that adsorbed to MuBL-Sepharose, while peptides from proteins that bound to MuLL-Sepharose shared homology with apolipophorin. This study revealed that digestive enzymes and transport proteins found in worker guts can be recognized by MuBL and MuLL. Thus, the mechanism of their termiticidal activity may involve changes in the digestion and absorption of nutrients. © 2018 Society of Chemical Industry.

Effects of Bt cabbage pollen on the honeybee Apis mellifera L

Honeybees may be exposed to insecticidal proteins from transgenic plants via pollen during their foraging activity. Assessing effects of such exposures on honeybees is an essential part of the risk assessment process for transgenic Bacillus thuringiensis (Bt) cabbage. Feeding trials were conducted in a laboratory setting to test for possible effects of Cry1Ba3 cabbage pollen on Italian-derived honeybees Apis mellifera L. Newly emerged A. mellifera were fed transgenic pollen, activated Cry1Ba3 toxin, pure sugar syrup (60% w/v sucrose solution), and non-transgenic cabbage pollen, respectively. Then the effects on survival, pollen consumption, weight, detoxification enzyme activity and midgut enzyme activity of A. mellifera were monitored. The results showed that there were no significant differences in survival, pollen consumption, weight, detoxification enzyme activity among all treatments. No significant differences in the activities of total proteolytic enzyme, active alkaline trypsin-like enzyme and weak alkaline trypsin-like enzyme were observed among all treatments. These results indicate that the side-effects of the Cry1Ba3 cabbage pollen on A. mellifera L. are unlikely.

Kinetic Characterization of Anticarsia gemmatalis Digestive Serine- Proteases and the Inhibitory Effect of Synthetic Peptides.

Enzyme kinetics contributes to understanding the structure and function of insect digestive serine proteases. Kinetic parameters allow to understanding active sites and mechanisms of enzymes efficacy, identifying the inhibition of the insects digestive protease system by inhibitors produced by plants, or via the application of synthetic inhibitors Objectives: The aim of this study was to purify digestive serine proteases of A. gemmatalis, determining their kinetic properties using the chromogenic substrates tripeptidyl and characterizing the effects of synthetic inhibitors on their activity. In order to provide new opportunities for sustainable pest management through the development of protease inhibitors. The enzymes were purified on p-aminobenzamidine agarose affinity column in an FPLC system using electrophoresis with 12.5% polyacrylamide gel. Michaelis-Menten constants and the inhibition model were determined according to the Dixon methodology and Lineweaver-Burk's double reciprocal. The KM values and catalytic constants of peptide substrates show that A. gemmatalis trypsin- like has a higher affinity for substrates with arginine in the P1 position. Inhibition by Gor 3, Gor 4, and Gor 5, in the presence of L-BApNA, was linear competitive. The inhibition constant for the Gor 5 peptide was higher due to its strong interaction with hydrophobic residues in the secondary site region of A. gemmatalis trypsin-like. It is observed that among the three peptides analyzed, the Gor 5 presented lower inhibition constant and therefore, the most potent among the tested ones. The predominance of hydrophobic residues in the region of the secondary site of the enzymes favored the interaction of the peptide. After characterization by three different types of graphs profiles, it is possible to verify that the inhibition model of the trypsin-like enzymes for the tested peptides is of the linear competitive type, in the concentration range of inhibitors and substrates analyzed. However, by the graphing profiles it is observed that the inhibition occurred due to the interaction of the peptides at the secondary site S2' in the hydrophobic cavity of the enzymes analyzed.

Inhibitory effect of Lactococcus lactis on the bioactivity of periodontopathogens.

Lactococcus lactis is a probiotic bacterium that produces various bacteriocins. Periodontopathogens induce inflammation and halitosis through the actions of lipopolysaccharide (LPS) and trypsin-like enzymes. The purpose of this study was to investigate the inhibitory effects of L. lactis on the bioactivity of periodontopathogens. To investigate the antimicrobial peptide of L. lactis, the spent culture medium (SCM) of L. lactis was treated with or without proteinase K after collection by centrifugation, and the antibacterial activity of SCM against periodontopathogens was assessed. To evaluate the neutralizing effect of L. lactis on halitosis, SCM of periodontopathogens was mixed with an L. lactis suspension, and the levels of volatile sulfur compounds (VSCs) were measured by gas chromatography. LPS from the periodontopathogens was extracted by an LPS extraction kit with little modification, and THP-1 cells as a monocytic cell line were treated with the extracted LPS in the presence or absence of UV-killed L. lactis. The production of inflammatory cytokines was analyzed by ELISA. The SCM of L. lactis exhibited antimicrobial activity against the periodontopathogens, whereas the proteinase K-treated SCM showed little antimicrobial activity. In addition, the L. lactis suspension had a neutralizing effect on the VSCs produced by periodontopathogens, and UV-killed L. lactis inhibited the production of IL-6 and TNF-α induced by the LPS. These results suggest that L. lactis may be a useful probiotic to prevent and treat periodontitis and halitosis.

Genome Wide Mapping of Peptidases in Rhodnius prolixus: Identification of Protease Gene Duplications, Horizontally Transferred Proteases and Analysis of Peptidase A1 Structures, with Considerations on Their Role in the Evolution of Hematophagy in Triatominae.

Triatominae is a subfamily of the order Hemiptera whose species are able to feed in the vertebrate blood (i.e., hematophagy). This feeding behavior presents a great physiological challenge to insects, especially in Hemipteran species with a digestion performed by lysosomal-like cathepsins instead of the more common trypsin-like enzymes. With the aim of having a deeper understanding of protease involvement in the evolutionary adaptation for hematophagy in Hemipterans, we screened peptidases in the Rhodnius prolixus genome and characterized them using common blast (NCBI) and conserved domain analyses (HMMER/blast manager software, FAT, plus PFAM database). We compared the results with available sequences from other hemipteran species and with 18 arthropod genomes present in the MEROPS database. Rhodnius prolixus contains at least 433 protease coding genes, belonging to 71 protease families. Seven peptidase families in R. prolixus presented higher gene numbers when compared to other arthropod genomes. Further analysis indicated that a gene expansion of the protease family A1 (Eukaryotic aspartyl protease, PF00026) might have played a major role in the adaptation to hematophagy since most of these peptidase genes seem to be recently acquired, are expressed in the gut and present putative secretory pathway signal peptides. Besides that, most R. prolixus A1 peptidases showed high frequencies of basic residues at the protein surface, a typical structural signature of Cathepsin D-like proteins. Other peptidase families expanded in R. prolixus (i.e., C2 and M17) also presented significant differences between hematophagous (higher number of peptidases) and non-hematophagous species. This study also provides evidence for gene acquisition from microorganisms in some peptidase families in R. prolixus: (1) family M74 (murein endopeptidase), (2) family S29 (Hepatitis C virus NS3 protease), and (3) family S24 (repressor LexA). This study revealed new targets for studying the adaptation of these insects for digestion of blood meals and their competence as vectors of Chagas disease.

Activation of the Nrf2 signaling pathway and neuroprotection of nigral dopaminergic neurons by a novel synthetic compound KMS99220

The transcription factor Nrf2 is known to induce gene expression of antioxidant enzymes and proteasome subunits. Because both oxidative stress and protein aggregation have damaging effects on neurons, activation of the Nrf2 signaling should be beneficial against neurodegeneration. In this study, we report a novel synthetic morpholine-containing chalcone KMS99220 that confers neuroprotection. It showed high binding affinity to the Nrf2 inhibitory protein Keap-1 and increased nuclear translocation of Nrf2 and gene expression of the antioxidant enzymes heme oxygenase-1, NAD(P)H:quinone oxidoreductase-1, and the catalytic and modifier subunits of glutamate-cysteine ligase in dopaminergic CATH.a cells. KMS99220 also increased expression of the proteasome subunits PSMB5, PSMB7, PSMB8 and PSMA1, and the respective chymotrypsin and trypsin-like proteasomal enzyme activities, and reduced α-synuclein aggregate in GFP-α-syn A53T-overexpressing cells. KMS99220 exhibited a favorable pharmacokinetic profile with excellent bioavailability and metabolic stability, did not interfere with activities of the cytochrome p450 isotypes, and showed no apparent in vivo toxicity when administered up to 2000 mg/kg. In 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice, oral administration of KMS99220 prevented degeneration of the nigral dopaminergic neurons, induced the Nrf2 target genes, and effectively prevented the associated motor deficits. These results suggest KMS99220 as a potential candidate for therapy against Parkinson's disease.

Enzymatic cleavage promotes disassembly of GII.3 norovirus virus like particles and its binding to salivary histo-blood group antigens

In this study, we found that addition of fecal extract significantly promoted the binding of GII.3 NoV VLPs to salivary HBGAs. SDS-PAGE analysis indicated that major capsid proteins (VP1) were cleaved into two major bands with molecular weights of 26 and 31kD, respectively. Pretreatment of fecal extract by boiling or addition of protease inhibitor cocktail or type specific protease inhibitor (leupeptin and aprotinin) during incubation all decreased VP1 cleavage and its binding to salivary HBGAs. Trypsin digestion led to cleavage of VP1 and promoted its binding to HBGAs, suggesting that the active enzyme(s) might be trypsin or trypsin-like enzymes. Trypsin and fecal extract pretreatment all led to loss of morphological intact VLPs, indicating enhanced signal was possible due to increased binding of fragmented subunits. N-terminal sequencing was performed to characterize the cleavage sites with indecisive results. In vitro VLP-salivary HBGAs binding blockade assay using VLPs derived from VP1 of different GII.3 strains and rabbit anti-genotype specific hyperimmune serum indicated that GII.3 NoVs might have conservative HBGA binding sites. In summary, our results provide evidence about the widespread presence of active enzyme in fecal samples that can cleave GII.3 NoV VLPs and demonstrate that GII.3 NoVs have conservative HBGA binding sites which might have implications in the design of multivalent NoV vaccines.