β-d-xylosidase from geobacillus thermoleovorans IT-08: Biochemical characterization and bioinformatics of the enzyme

Ratnadewi, A.A.I.^a,

Fanani, M.^b,

Kurniasih, S.D.^c,

Sakka, M.^d,

Wasito, E.B.^b,

Sakka, K.^d,

Nurachman, Z.^c ,

Puspaningsih, N.N.T.^be 

^a  Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Jember, Jalan Kalimantan 37, Jember 68121, Indonesia
^b  Proteomic Laboratory of Institute of Tropical Diseases, Universitas Airlangga, Kampus C Mulyorejo, Surabaya 60115, Indonesia

Abstract

The gene encoding a thermostable β-d-xylosidase (GbtXyl43B) from Geobacillus thermoleovorans IT-08 was cloned in pET30a and expressed in Escherichia coli; additionally, characterization and kinetic analysis of GbtXyl43B were carried out. The gene product was purified to apparent homogeneity showing M _r of 72 by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme exhibited an optimum temperature and pH of 60 C and 6.0, respectively. In terms of stability, GbtXyl43B was stable at 60 C at pH 6.0 for 1 h as well as at pH 6-8 at 4 C for 24 h. The enzyme had a catalytic efficiency (k _cat/K _M) of 0.0048 ± 0.0010 s^-1 mM^-1 on p-nitrophenyl-β-d- xylopyranoside substrate. Thin layer chromatography product analysis indicated that GbtXyl43B was exoglycosidase cleaving single xylose units from the nonreducing end of xylan. The activity of GbtXyl43B on insoluble xylan was eightfold higher than on soluble xylan. Bioinformatics analysis showed that GbtXyl43B belonging to glycoside hydrolase family 43 contained carbohydrate-binding module (CBM; residues 15 to 149 forming eight antiparallel β-strands) and catalytic module (residues 157 to 604 forming five-bladed β-propeller fold with predicted catalytic residues to be Asp287 and Glu476). CBM of GbtXyl43B dominated by the Phe residues which grip the carbohydrate is proposed as a novel CBM36 subfamily.

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http://link.springer.com/article/10.1007%2Fs12010-013-0329-5

Effect of Lead on Survival, Osmoregulation, and Histological Changes of the Gills of the White Shrimp, Litopenaeus vannamei, Boone, 1931

Usman, N.^ab,

Irawan, B.^a,

Soegianto, A.^a

^a  Department of Biology, Faculty of Sciences and Technology, AirlanggaUniversity, Kampus C Unair, Jl. Mulyorejo, Surabaya 60115, Indonesia
^b  Department of Fishery, Faculty of Marine Sciences and Technology, University of Hang Tuah, Jl. Arif Rahman Hakim, Surabaya 60222, Indonesia 

Abstract

The purpose of this study was to evaluate the acute toxicity of lead for different life stages of shrimp, Litopenaeus vannamei, and to determine the effect of its sublethal concentrations on osmoregulatory capacity (OC) as well as the possible histological alteration in the gills of juvenile shrimp. The 24-, 48-, and 96-h LC₅₀values for lead to L. vannamei increased progressively with increasing life stage, from nauplii<zoeae<mysis<postlarvae<juvenile. After 15-d exposure to 3.25, 6.50, and 9.75mg Pb/L, the OC values of exposed shrimp were reduced by 39, 73, and 157%, respectively compared to control animals. Compared to controls, the lead concentrations in gill tissues increased significantly by 127,500, 137,500, and 141,000% in shrimps exposed to 3.25, 6.50, and 9.75mg Pb/L, respectively. After lead exposure, hemocytic congestion in efferent vessels and multiple hyperplasia were observed in gill filaments, resulting in narrowed hemolymphatic lacuna. The histopathological effects increased with increasing Pb concentration. © Copyright by the World Aquaculture Society 2013.

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http://onlinelibrary.wiley.com/doi/10.1111/jwas.12054/abstract

Antecedents to intention to engage in the online negative word-of-mouth communication  

Mardhiyah, D.^ab ,

Dharmmesta, B.S.^b,

Purwanto, B.M.^b

^a  UniversitasAirlangga,Indonesia
^b  Universitas Gadjah Mada, Indonesia 

Abstract

Complaints delivered directly to a firm will not be a problem if they can be handled properly, while the ones that are not disclosed directly to the firm but to a third party or even warnings to others not to use particular products or services, will be negative word-of-mouth communication. It can damage the image of the firm and be very detrimental. The purpose of this study was to analyze the antecedents of intention to engage in negative online word-of-mouth communication that includes dissatisfaction, service importance, success of complaint, complaint benefit, self confidence, altruism, retaliatory intention, and complaint cost. Medical services were selected considering the impact caused by the negligence of the service provider possibly giving rise to negative word-of-mouth communication. The online environment has been considered because of the developments in technology which provide opportunities for consumers to communicate with ach other. In addition, the dissemination of information through online media can spread incredibly widely and rapidly. The samples in this study comprised consumers of medical services who had disappointing experiences in using those services either directly or indirectly. A total of 123 questionnaires were analyzed with multiple regression analysis to test the research hypothesis. The results showed that the factors influencing the intentions behind negative online word-of-mouth communication were success of complaint, altruism, retaliatory intention, and complaint cost.

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https://www.google.co.id/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwivvtDTlLTPAhXJtY8KHdr_AzkQFggfMAA&url=http%3A%2F%2Fjournal.ugm.ac.id%2Fgamaijb%2Farticle%2Fview%2F5698&usg=AFQjCNHEFuWjony3sV3VelusJtGofYhgvA&sig2=gzle_DZdeQjc1GxoScubKg

Design of multimode tapered fibre sensor for glucose detection  

Yasin, M.^a ,

Ahmad, H.^b,

Thambiratnam, K.^b,

Jasim, A.A.^bc,

Phang, S.W.^d,

Harun, S.W.^bc

^a  Department of Physics, Airlangga University, Surabaya 60115, Indonesia
^b  Photonics Research Centre, Department of Physics, University of Malaya, Kuala Lumpur 50603, Malaysia 

Abstract

In this paper the comparison behaviour between a tapered silica Multi-Mode Fibre (MMF) and a Plastic Multi-Mode (PMM) fibre is proposed. The tapered silica MMF (tapered core and cladding) and PMM fibre (only core) sensors use a Tunable Laser Source (TLS) at 1550 nm and a yellow He-Ne laser at 594 nm as the sources for measuring the attenuation of the input signal when the sensor is being soaked into the glucose solution. From this work, the tapered PMM fibre performs better in terms of its linearity, and provides a reliable calibration graph of glucose concentration against output signal. It has a sensitivity of 0.0088 mV/% and an error of 2.6 percent with a resolution of 0.36%. The tapered silica MMF has a better sensitivity, error and a better resolution but a lesser degree of linearity.

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https://www.google.co.id/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwj2zp6PlLTPAhXGOY8KHcNFC3kQFggkMAA&url=http%3A%2F%2Frepository.um.edu.my%2F93738%2F&usg=AFQjCNEjhthSxohtdzMbuPlaiSQOxKunPw&sig2=apt0iy_naWdmm_TNZHrq6g

Antiviral activities of Indonesian medicinal plants in the East Java region against hepatitis C virus

Wahyuni, T.S.^ac,

Tumewu, L.^b,

Permanasari, A.A.^b,

Apriani, E.^b,

Adianti, M.^bc,

Rahman, A.^a,

Widyawaruyanti, A.^a,

Lusida, M.I.^b,

Fuad, A.^a,

Soetjipto^b,

Nasronudin^b,

Fuchino, H.^d,

Kawahara, N.^d,

Shoji, I.^c,

Deng, L.^c,

Aoki, C.^ce,

Hotta, H.^c 

^a  Department of Pharmacognocy and Phytochemistry, Faculty of Pharmacy, Airlangga University,Surabaya,Indonesia^b  

Abstract

Background: Hepatitis C virus (HCV) is a major cause of liver disease and a potential cause of substantial morbidity and mortality worldwide. The overall prevalence of HCV infection is 2%, representing 120 million people worldwide. Current standard treatment using pegylated interferon and ribavirin is effective in only 50% of the patients infected with HCV genotype 1, and is associated with significant side effects. Therefore, it is still of importance to develop new drugs for treatment of HCV. Antiviral substances obtained from natural products, including medicinal plants, are potentially good targets to study. In this study, we evaluated Indonesian medicinal plants for their anti-HCV activities. Methods: Ethanol extracts of 21 samples derived from 17 species of medicinal plants explored in the East Java region were tested. Anti-HCV activities were determined by a cell culture method using Huh7.5 cells and HCV strains of 9 different genotypes (1a to 7a, 1b and 2b). Results: Four of the 21 samples tested showed antiviral activities against HCV: Toona sureni leaves (TSL) with 50% inhibitory concentrations (IC50) of 13.9 and 2.0 μg/ml against the HCV J6/JFH1-P47 and -P1 strains, respectively, Melicope latifolia leaves (MLL) with IC50 of 3.5 and 2.1 μg/ml, respectively, Melanolepis multiglandulosa stem (MMS) with IC50 of 17.1 and 6.2 μg/ml, respectively, and Ficus fistulosa leaves (FFL) with IC50 of 15.0 and 5.7 μg/ml, respectively. Time-of-addition experiments revealed that TSL and MLL inhibited both at the entry and post-entry steps while MMS and FFL principally at the entry step. TSL and MLL inhibited all of 11 HCV strains of all the genotypes tested to the same extent. On the other hand, FFL showed significantly weaker inhibitory activities against the HCV genotype 1a strain, and MMS against the HCV strains of genotypes 2b and 7a to a lesser extent, compared to the other HCV genotypes. Conclusions: Ethanol extracts of TSL, MLL, MMS and FFL showed antiviral activities against all the HCV genotypes tested with the exception that some genotype(s) showed significant resistance to FFL and to MMS to a lesser extent. These plant extracts may be good candidates for the development of anti-HCV drugs. © 2013 Wahyuni et al.

Full Text :

http://virologyj.biomedcentral.com/articles/10.1186/1743-422X-10-259