Understanding a Core Pilin of the Type IVa Pili of Acidithiobacillus thiooxidans, PilV

( Araceli Hernández-sánchez ),( Edgar D. Páez-pérez ),( Elvia Alfaro-saldaña ),( Vanesa Olivares-illana ),( J. Viridiana García-meza ) 한국미생물생명공학회 2024 Journal of microbiology and biotechnology Vol.34 No.3

Pilins are protein subunits of pili. The pilins of type IV pili (T4P) in pathogenic bacteria are well characterized, but anything is known about the T4P proteins in acidophilic chemolithoautotrophic microorganisms such as the genus Acidithiobacillus. The interest in T4P of A. thiooxidans is because of their possible role in cell recruitment and bacterial aggregation on the surface of minerals during biooxidation of sulfide minerals. In this study we present a successful ad hoc methodology for the heterologous expression and purification of extracellular proteins such as the minor pilin PilV of the T4P of A. thiooxidans, a pilin exposed to extreme conditions of acidity and high oxidation-reduction potentials, and that interact with metal sulfides in an environment rich in dissolved minerals. Once obtained, the model structure of A. thiooxidans PilV revealed the core basic architecture of T4P pilins. Because of the acidophilic condition, we carried out in silico characterization of the protonation status of acidic and basic residues of PilV in order to calculate the ionization state at specific pH values and evaluated their pH stability. Further biophysical characterization was done using UV-visible and fluorescence spectroscopy and the results showed that PilV remains soluble and stable even after exposure to significant changes of pH. PilV has a unique amino acid composition that exhibits acid stability, with significant biotechnology implications such as biooxidation of sulfide minerals. The biophysics profiles of PilV open new paradigms about resilient proteins and stimulate the study of other pilins from extremophiles.

Improvement of the Quality and Shelf-life of Corn Tortillas by Water Soluble Chitosan

( Araceli Loredo-trevino ),( Alfonso Ocampo-ramirez ),( Ana Veronica Charles-rodriguez ),( Maria De La Luz Reyes-vega ),( Cristobal N. Aguilar ),( Juan Carlos Contreras-esquivel ) 한국키틴키토산학회 2018 한국키틴키토산학회지 Vol.23 No.1

Chitosan-oligosaccharides and water soluble chitosan have wide applications in several industries such as agronomic, cosmetic, feed, food, medicine, and nanotechnology. The aim of this work was to depolymerize chitosan enzymatically using endo-chitosanase from Bacillus sp. and to evaluate the hydrolyzates as fungistatic on corn tortillas prepared with these products. Five water soluble chitosan (2, 4, 8, 12 and 24 h) series were prepared with endo-chitosanase (40ºC, 3.5 U/g chitosan). Two filamentous fungi of contaminated corn tortillas were isolated and later used for the inhibition studies of water soluble chitosan series on agar plates. Furthermore, corn tortillas were elaborated with water soluble chitosan obtained after 4 h of enzyme degradation to evaluate the microbial inhibition effect and sensorial analysis. All water soluble chitosan series were totally soluble in water, except that material modified enzymatically by 2 h. The fungal strains isolated from corn tortillas were Aspergillus sp. and Penicillum sp. Results on microbial radial growth showed that the water soluble chitosan series obtained at the time of 4 h had the biggest effectiveness for the inhibition of growth of both filamentous fungi on agar plate. When the corn tortillas were prepared with water soluble chitosan at a 1% (w/v), a partial inhibition of growth of filamentous fungi was achieved in contrast to the prepared tortillas without this hydrolyzate. Unpleasant flavor was not presented in the corn tortillas by effect of the hydrolyzate addition; this indicates that this material can be used appropriately as food additive in the tortilla industry as inhibitor of microbial growth. This water soluble chitosan can also be considered as a dietary fiber and a prebiotic.

HIGHER ORDER GENOCCHI, EULER POLYNOMIALS ASSOCIATED WITH q-BERNSTEIN TYPE POLYNOMIALS

Arac, Serkan,Erdal, Dilek The Honam Mathematical Society 2011 호남수학학술지 Vol.33 No.2

The main aim of this paper is to give some relationships between q-Bernstein, higher order genocchi and Euler polynomials.

A NOTE ON THE WEIGHTED q-GENOCCHI NUMBERS AND POLYNOMIALS WITH THEIR INTERPOLATION FUNCTION

Arac, Serkan,Ackgoz, Mehmet,Seo, Jong-Jin The Honam Mathematical Society 2012 호남수학학술지 Vol.34 No.1

Recently, T. Kim has introduced and analysed the q-Bernoulli numbers and polynomials with weight ${\alpha}$ cf.[7]. By the same motivaton, we also give some interesting properties of the q-Genocchi numbers and polynomials with weight ${\alpha}$. Also, we derive the q-extensions of zeta type functions with weight from the Mellin transformation of this generating function which interpolates the q-Genocchi polynomials with weight at negative integers.

A NOTE ON THE WEIGHTED q−HARDY-LITTLEWOOD- TYPE MAXIMAL OPERATOR WITH RESPECT TO q−VOLKENBORN INTEGRAL IN THE p−ADIC INTEGER RING

Serkan Arac,Mehmet A 한국전산응용수학회 2013 Journal of applied mathematics & informatics Vol.31 No.3

The essential aim of this paper is to dene weighted q-Hardylittlewood-type maximal operator by means of p-adic q-invariant distributionon Zp. Moreover, we give some interesting properties concerning thistype maximal operator.

Fishery resource management in Sri Lanka

Manoj Presanga Thisakutti Arac 한국수산과학회 양식분과 2022 한국수산과학회 양식분과 학술대회 Vol.2022 No.5

Isolation of Antibacterial Hydrolysates from Hen Egg White Lysozyme and Identification of Antibacterial Peptides

Wilman Carrillo,Araceli Lucio,Juan Gaibor,Dayana Morales,Grace Vasquez 한국식품영양과학회 2018 Journal of medicinal food Vol.21 No.8

Native and heated hen egg white lysozyme (HEWL) hydrolysates were isolated by hydrolysis with pepsin at pH 2.0 in situ in a cation exchange membrane to isolate and identify antibacterial peptides of the HEWL hydrolysates. Native and heated HEWL was partially hydrolyzed with pepsin at pH 2.0. The fractions were eluted with 5 M ammonia to identify 23 antibacterial peptides using a tandem mass spectrometry. Then, these fractions were eluted with a solution of NaCl 1 M, and seven positively charged peptides f(23–28) YSLGNW, f(122–129) AWIRGCRL, f(123–129) WIRGCRL, f(124–129) IRGCRL, f(82–96) ALLSSDITASVNCAK, f(103–129) VAWRNRCKGTDVQAWIRGCRL, and f(97–123) KIVSDGNGMNAWVAWRNRCKGT were identified using tandem mass spectrometry. Native HEWL hydrolysate presented an enzymatic activity of 23.0%, heated HEWL hydrolysate at pH 6.0 presented a residual enzymatic activity of 22.0%, and heated HEWL hydrolysate at pH 7.0 presented an enzymatic activity of 21.33%. Native and heated HEWL hydrolysate presented antibacterial activity against Escherichia coli and Staphylococcus carnosus. Native HEWL hydrolysate presented a higher enzymatic activity than heated HEWL hydrolysates.

Diagnosis and Management of Grain-Induced Asthma

Santiago Quirce,Araceli Diaz-Perales 대한천식알레르기학회 2013 Allergy, Asthma & Immunology Research Vol.5 No.6

Grain-induced asthma is a frequent occupational allergic disease mainly caused by inhalation of cereal flour or powder. The main professions affectedare bakers, confectioners, pastry factory workers, millers, farmers, and cereal handlers. This disorder is usually due to an IgE-mediated allergicresponse to inhalation of cereal flour proteins. The major causative allergens of grain-related asthma are proteins derived from wheat, rye and barleyflour, although baking additives, such as fungal α-amylase are also important. This review deals with the current diagnosis and treatment of grain-inducedasthma, emphasizing the role of cereal allergens as molecular tools to enhance diagnosis and management of this disorder. Asthma-like symptomscaused by endotoxin exposure among grain workers are beyond the scope of this review. Progress is being made in the characterization of grainand bakery allergens, particularly cereal-derived allergens, as well as in the standardization of allergy tests. Salt-soluble proteins (albumins plus globulins),particularly members of the α-amylase/trypsin inhibitor family, thioredoxins, peroxidase, lipid transfer protein and other soluble enzymes showthe strongest IgE reactivities in wheat flour. In addition, prolamins (not extractable by salt solutions) have also been claimed as potential allergens. However, the large variability of IgE-binding patterns of cereal proteins among patients with grain-induced asthma, together with the great differencesin the concentrations of potential allergens observed in commercial cereal extracts used for diagnosis, highlight the necessity to standardize andimprove the diagnostic tools. Removal from exposure to the offending agents is the cornerstone of the management of grain-induced asthma. Theavailability of purified allergens should be very helpful for a more refined diagnosis, and new immunomodulatory treatments, including allergen immunotherapyand biological drugs, should aid in the management of patients with this disorder.

The Impact of Inherited Thrombophilia Types and Low Molecular Weight Heparin Treatment on Pregnancy Complications in Women with Previous Adverse Outcome

Vedran Stefanovic,Nada Aracic,Damir Roje,Ivana Alujevic Jakus,Marinela Bakotin 연세대학교의과대학 2016 Yonsei medical journal Vol.57 No.5

Purpose: To assess the distribution of births and spontaneous abortions, first-trimester abortion (FTA) and mid-trimester abortion(MTA), in untreated (n=128) and low molecular weight heparin (LMWH) treated pregnancies (n=50) of the same women with inheritedthrombophilias and adverse pregnancy outcome (APO) in previous pregnancies. We particularly investigated the impact ofLMWH on reducing the pregnancy complications in two thrombophilia types, “Conventional” and “Novel”. Materials and Methods: 50 women with inherited thrombophilia (26 Conventional and 24 Novel) and APO in previous pregnancieswere included in the study. Conventional group included factor V Leiden (FVL), prothrombin G20210A (PT) mutations and antithrombin(AT), protein S (PS), and protein C (PC) deficiency, while the Novel group included methylentetrahydrofolate-reductase(MTHFR), plasminogen activator inhibitor-1 (PAI-1), and angiotensin converting enzyme (ACE) polymorphism. APO was definedas one of the following: preterm birth (PTB), fetal growth restriction (FGR), preeclampsia (PE), intrauterine fetal death (IUFD), placentalabruption (PA) and deep venous thrombosis (DVT). Results: There was no difference in distribution of births and spontaneous abortions between Conventional and Novel thrombophiliain untreated pregnancies (χ2=2.7; p=0.100) and LMWH treated pregnancies (χ2=0.442; p=0.506). In untreaed pregnancies thrombophiliatype did not have any impact on the frequency of FTA and MTA (χ2=0.14; p=0.711). In birth-ended pregnancies LMWH treatementreduced the incidence of IUFD (p=0.011) in Conventional and FGR, IUFD, and PTB in Novel thrombophilia group. Conclusion: The equal impact of two thrombophilia types on the pregnancy outcomes and a more favorable effect of LMWH therapyon pregnancy complications in Novel thrombophilia group point the need for Novel thrombophilias screening and the futurestudies on this issue should be recommended.

Stability Analysis of a Family of Continuous State Feedback Synthesis: Theory and Experiments

Raúl Santiesteban-Cos,Araceli Gárate-García,Oscar Montaño-Godinez 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.3

A family of continuous state feedback synthesis based on sliding mode control is analyzed using aLyapunov approach, such that the compensation of growing perturbations together with state variables is shown. Robustness properties of a family of controllers, varying from the well known twisting sliding mode control law tothe PD controller, are studied. A non-smooth Lyapunov function is proposed such that global finite-time stabilityof the origin is demonstrated and tuning rules for the control gains are obtained. Moreover, since the Lyapunovfunction is strict, an upper bound for the convergence time of the closed loop system can be estimated, in spite ofthe growing perturbations with respect to the state. To illustrate the performance and robustness properties of thefeedback synthesis, experimental results are presented, using a one-link pendulum as a test bed.