New Hydroxylated Cationic Gemini Surfactants as Effective Corrosion Inhibitors for Mild Steel in Hydrochloric Acid Medium

Inhibitory action of hydroxylated cationic gemini surfactants on corrosion of mild steel [MS] in 1 M hydrochloric acid medium is studied by gravimetric, electrochemical polarization and electrochemical impedance spectroscopic (EIS) techniques. The results obtained reveal that these compounds are very efficient inhibitors. The inhibitory action of surfactants increases with the concentration and chain length. Concentration as low as 10−5 M of 16–4–16 MEA could show 99% inhibition whereas 12–4–12 MEA showed 93% inhibition at 10−4 M concentration. The inhibition efficiency versus concentration curves show an S-shape plot indicating adsorption of surfactants on metal surface as a three steps process. From Arrhenius plots corrosion rate of MS was observed to decrease at any given temperature with inhibitor concentration due to the increase in the degree of surface coverage. In contrast, at constant inhibitor concentration, the corrosion rate increases with temperature. EIS measurements show increase in the charge transfer resistance with the inhibitor concentration.

Polygalacturonase-inhibiting proteins--leucine-rich repeat proteins in plant defence

Plant polygalacturonase-inhibiting proteins (PGIPs) belong to the leucine-rich repeat (LRR) family and are known to prevent pathogen invasion by inhibiting the plant cell wall degrading enzyme, polygalacturonase. Our study reveals that these multigene-encoded defence proteins found in flowering plants only exhibit identical domain architecture with 10 tandemly-arranged LRRs. This implies that variations of PGIP inhibitory properties are not associated with the number of the repeats but with subtle changes in the sequence content of the repeats. The first and eighth repeat contain more mutations compared to the strict conservation of the plant-specific LRRs or any repeat at other positions. Each of these repeats forms a separate cluster in the phylogenetic tree, both within and across plant families, thus suggesting uniqueness with respect to their position. A study of the genes encoding PGIPs, shows the existence of two categories (i) single exon and hence no intron; and (ii) two exons with an intron in between. Analyses of the intron phase and correlation of the exon-intron structure with the compact structural modules in PGIPs support insertion of introns in the pre-existing single exon genes and thus the intron late model. Lack of conservation of phase across families and formation of individual clusters for each family in the phylogenetic tree drawn with the intron sequences illustrate the event of insertion that took place separately in each of these families.

Dengue virus activates polyreactive, natural IgG B cells after primary and secondary infection

BACKGROUND

Dengue virus is transmitted by mosquitoes and has four serotypes. Cross-protection to other serotypes lasting for a few months is observed following infection with one serotype. There is evidence that low-affinity T and/or B cells from primary infections contribute to the severe syndromes often associated with secondary dengue infections. such pronounced immune-mediated enhancement suggests a dengue-specific pattern of immune cell activation. This study investigates the acute and early convalescent B cell response leading to the generation of cross-reactive and neutralizing antibodies following dengue infection.

METHODOLOGY/PRINCIPAL FINDINGS

We assayed blood samples taken from dengue patients with primary or secondary infection during acute disease and convalescence and compared them to samples from patients presenting with non-dengue related fever. Dengue induced massive early plasmablast formation, which correlated with the appearance of polyclonal, cross-reactive IgG for both primary and secondary infection. Surprisingly, the contribution of IgG to the neutralizing titer 4-7 days after fever onset was more than 50% even after primary infection.

CONCLUSIONS/SIGNIFICANCE

Poly-reactive and virus serotype cross-reactive IgG are an important component of the innate response in humans during both primary and secondary dengue infection, and "innate specificities" seem to constitute part of the adaptive response in dengue. While of potential importance for protection during secondary infection, cross-reactive B cells will also compete with highly neutralizing B cells and possibly interfere with their development.

Antibacterial potential assessment of jasmine essential oil against e. Coli

The antibacterial activity of Jasmine (Jasminum sambac L.) flower hydro steam distilled essential oil, synthetic blends and six major individual components was assessed against Escherichia coli (MTCC-443) strain. The activity was bactericidal. Minimum inhibitory concentration was determined by tube dilution technique, and the Minimum inhibitory concentration ranged between 1.9-31.25 μl/ml. Phenolcoefficient of the oil, synthetic blends and components varied between 0.6-1.7. The activity of the chemicals was possibly due to the inhibition of cell membrane synthesis.

Acclimatory response to hydrogen peroxide and glutathione under salt-boron stress through their impact on mineral nutrition and antioxidant defense system in pigeonpea (Cajanus cajan L.)

Investigations were carried out on a salt tolerant (Manak, H77-216) and a comparatively salt sensitive (ICPL 88039) genotypes of pigeonpea (Cajanus cajan L. Millsp.) under NaCl, B and NaCl + B stress to examine the acclimatory response to H2O2, glutathione and H2O2 + glutathione through their effect on mineral nutrition, morpho-physiological parameters and antioxidant defense system. Both B and NaCl alone and their combinations had deleterious effect on dry biomass of plumule, enhanced relative stress injury (RSI), lipid peroxidation with concomitant increase in Na, Cl and B contents. However it did not bear any correlation with osmotic potential of plumule and K contents. Antioxidative enzymes like superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), peroxidase (POX) and glutathione reductase (GR) also decreased with salt, B and salt + B treatments. However contents of H2O2 enhanced and that of ascorbate declined under aforementioned treatments. These injurious effects are partially alleviated by exogenous application of H2O2; glutathione (GSH) and H2O2 + GSH treatments. The role of H2O2 and GSH in the present study is suggestive of triggering multifunctional signal transduction in plant defense mechanisms to prevent cellular oxidation, membrane injury, lipid peroxidation and protein enzyme inactivation.

Extrapolated Biogeography-Based Optimization (eBBO) for Global Numerical Optimization and Microstrip Patch Antenna Design

Biogeography-Based Optimization (BBO) uses the idea of probabilistically sharing features between solutions based on the solutions’ fitness values. Therefore, its exploitation ability is good but it lacks in exploration ability. In this paper, the authors extend the original BBO and propose a hybrid version combined with ePSO (particle swarm optimization with extrapolation technique), namely eBBO, for unconstrained global numerical optimization problems in the continuous domain. eBBO combines the exploitation ability of BBO with the exploration ability of ePSO effectively, which can generate global optimum solutions. To validate the performance of eBBO, experiments have been conducted on 23 standard benchmark problems with a range of dimensions and diverse complexities and compared with original BBO and other versions of BBO in terms of the quality of the final solution and the convergence rate. Influence of population size and scalability study is also considered and results are compared with statistical paired t-test. Experimental analysis indicates that the proposed approach is effective and efficient and improves the exploration ability of BBO.

First- and second-line drug resistance patterns among previously treated tuberculosis patients in India

Culture and drug susceptibility testing results of 2816 tuberculosis (TB) patients from across India who had failed repeated treatments from 2001 to 2004 were retrospectively analysed at the Tuberculosis Research Centre, Chennai. Of 1498 (53%) identified as having multidrug-resistant TB (MDR-TB), 671 (44.8%) were resistant to > or =1 second-line drugs (SLDs): 490 (32.7%) to ethionamide, 245 (16.4%) to ofloxacin and 169 (11.3%) to kanamycin; 69 (4.6%) were extensively drug-resistant TB (XDR-TB). Although from a highly select and non-representative patient group, such high SLD resistance levels, including XDR-TB, among MDR-TB patients is of concern. The prevention of MDR/XDR-TB through quality DOTS services, however, remains the priority. In addition, rapid scale-up of quality programmatic management under the RNTCP is needed, with more control and rational use of SLDs outside the programme.

Effects of Sodium Nitroprusside Activity of Acid and Alkaline Invertases and Alkaline Phosphatase in Lemongrass (Cymbopogon flexuosus Steud) Wats

We investigated effects of sodium nitroprusside (SNP) on sucrose metabolizing enzymes, acid, and alkaline invertase and alkaline phosphatase in lemongrass (Cymbopogon flexuosus Steud) Wats varieties i.e. Krishna, Cauveri, Nima and Cheerharit. Fifteen day old lemongrass tillers were treated with SNP (1 and 2 mM) under sunlight for four hours. Our results clearly indicated that SNP (2 mM) substantially decreased the amount of proteins in all varieties studied, with maximum values of 40% and 33% in Nima and Krishna, respectively. SNP (1 mM) significantly increased the amount of proteins 43% and 31% in Krishna and Cauveri, respectively. SNP (2 mM) rapidly and severely reduced the activity of acid and alkaline invertases in all varieties, except Krishna and Cauveri. However, the effect of SNP was more pronounced on acid invertase causing at 2 mM an inhibition of 37%, 35% and 28% in Cheerharit, Nima and Cauveri, respectively, whereas it showed relatively less inhibition in alkaline invertase activity 27%, 24% and 21%, respectively, in Nima, Krishna and Cheerharit. Alkaline phosphatase activity was only considerably decreased following SNP (2 mM) treatment in all lemongrass varieties studied with the exception of Nima, where a sharp decrease of 50% was observed. SNP (1 mM) also demonstrated similar effects on acid and alkaline invertases and alkaline phosphatase. These results clearly suggest that SNP affects acid and alkaline phosphatase activity and, therefore, has a role in sucrose metabolism in lemongrass. Alterations in alkaline phosphatase activity upon SNP treatment have several consequences.

Formaldehyde-inactivated whole-virus vaccine protects a murine model of enterovirus 71 encephalomyelitis against disease

Enterovirus 71 (EV71) causes childhood hand, foot, and mouth disease and neurological complications, and no vaccines or therapeutic drugs are currently available. Formaldehyde-inactivated whole-virus vaccines derived from EV71 clinical isolates and a mouse-adapted virus (MAV) were tested in a mouse model of EV71 encephalomyelitis. After only two immunizations, given to mice at 1 and 7 days of age, the MAV vaccine protected mice at 14 days of age from disease. Tissues from immunized mice were negative for virus by viral culture, reverse transcriptase PCR, immunohistochemistry analysis, and in situ hybridization. Cross-neutralizing EV71 antibodies to strains with genotypes B3, B4, and C1 to C5 generated in immunized adult mice were able to passively protect 14-day-old mice from disease.

The use of two-dimension electrophoresis to identify serum biomarkers from patients with dengue haemorrhagic fever

Dengue infection is a major public health problem affecting millions of people living in tropical countries. With no suitable vaccines and specific antiviral drugs, treatment for dengue is usually symptomatic and supportive. Early diagnosis and recognition of severe disease is therefore crucial for better management of the patient. Two-dimension electrophoresis was used to identify disease-associated proteins that can be used for diagnosis and as drug targets for treatment. Two markers, identified by mass spectrometry analysis as alpha1-antitrypsin and NS1 proteins were found to be upregulated in dengue fever (DF; n=10) and dengue haemorrhagic fever (DHF; n=10) patients compared with healthy individuals (n=8). Both alpha1-antitrypsin and NS1 proteins were overexpressed two-fold in DHF patients compared with DF patients. Our study suggests that alpha1-antitrypsin and NS1 protein could be used as biomarkers as early indicators of DHF risk among patients with suspected dengue infection.

Dengue virus regulates type I interferon signalling in a strain-dependent manner in human cell lines

Outbreaks of dengue disease are constant threats to tropical and subtropical populations but range widely in severity, from mild to haemorrhagic fevers, for reasons that are still elusive. We investigated the interferon (IFN) response in infected human cell lines A549 and HepG2, using two strains (NGC and TSV01) of dengue serotype 2 (DEN2) and found that the two viruses exhibited a marked difference in inducing type I IFN response. While TSV01 infection led to activation of type I antiviral genes such as EIF2AK2 (PKR), OAS, ADAR and MX, these responses were absent in NGC-infected cells. Biochemical analysis revealed that NGC but not TSV01 suppressed STAT-1 and STAT-2 activation in response to type I IFN (alpha and beta). However, these two strains did not differ in their response to type II IFN (gamma). Although unable to suppress IFN signalling, TSV01 infection caused a weaker IFN-beta induction compared with NGC, suggesting an alternative mechanism of innate immune escape. We extended our study to clinical isolates of various serotypes and found that while MY10245 (DEN2) and MY22713 (DEN4) could suppress the IFN response in a similar fashion to NGC, three other strains of dengue [EDEN167 (DEN1), MY02569 (DEN1) and MY10340 (DEN2)] were unable to suppress the IFN response, suggesting that this difference is strain-dependent but not serotype-specific. Our report indicates the existence of a strain-specific virulence factor that may impact on disease severity.

Differential expression of aldolase, alpha tubulin and thioredoxin peroxidase in peripheral blood mononuclear cells from dengue fever and dengue hemorrhagic fever patients

We determined the differential expression levels of proteins in peripheral blood mononuclear cells of patients with dengue fever (DF) and dengue hemorrhagic fever (DHF). Proteins were subjected to two-dimensional electrophoresis, mass spectrometry and Western blot analysis. We identified 8 proteins that were 2-fold or more up-regulated in patients compared to healthy control, three of which, aldolase, thioredoxin peroxidase and alpha tubulin, were related to dengue infection. Both thioredoxin peroxidase and alpha tubulin were over-expressed 4.9 and 3.3 times respectively in DHF compared to DF patients while aldolase was up-regulated 2.2 times in DF compared to DHF patients. Alpha tubulin and thioredoxin peroxidase have the potential to be utilized as biomarkers for DHF.

Complete genome sequence analysis of dengue virus type 2 isolated in Brunei

In a previous study, we have reported the detection and isolation of dengue virus in Brunei (Osman, O., Fong, M.Y., Devi, S., 2007. A preliminary study of dengue infection in Brunei. JJID 60 (4), 205-208). DEN-2 was the predominant serotype followed by DEN-1. The full genomic sequences of 3 DEN-2 viruses isolated during the 2005-2006 dengue incident in Brunei were determined. Twenty-five primer sets were designed to amplify contiguous overlapping fragments of approximately 500-600 base pairs spanning the entire sequence of the viral genome. The amplified PCR products were sent for sequencing and their nucleotides and the deduced amino acids were determined. All three DEN-2 virus isolated were clustered in the Cosmopolitan genotype of the DEN-2 classification by Twiddy et al. This work constitutes the first complete genetic characterization of three Brunei DEN-2 virus strains.

Association of GSTM1, GSTT1, and GSTM3 gene polymorphisms and susceptibility to cervical cancer in a North Indian population

OBJECTIVE

The objective of the study was to evaluate the influence of genetic polymorphisms of GSTM1, GSTT1, and GSTM3 on the susceptibility of cervical cancer.

STUDY DESIGN

Blood samples from 150 women with biopsy-confirmed cervical cancer and 168 healthy controls were analyzed by multiplex polymerase chain reaction (PCR) to detect the presence or absence of GSTM1 and GSTT1. Insertion/deletion polymorphism in intron 6 of GSTM3 was determined by PCR.

RESULTS

The frequencies of homozygous GSTM1 null and GSTT1 null genotypes were found to be significantly higher in cancer patients as compared with healthy controls (P = .009, odds ratio [OR] 1.52, 95% confidence interval [CI], 1.1 to 2.0 and P = .0004, OR 2.4, 95% CI: 1.4 to 4.0, respectively). The AB genotype of GSTM3 also conferred higher risk of cancer (P = .053, OR 1.64, 95% CI, 1.0 to 2.6). However, no significant association of at-risk genotypes was observed with any stages of cervical cancer. Interactions among GSTM1 null, GSTT1 null, and AB genotype of GSTM3 resulted in additive predictive risks of cervical cancer. In case-only analysis, carriers of the AA genotype of GSTM3 among tobacco users were at elevated risk of cervical cancer (P = .024, OR 2.1, 95% CI, 1.0 to 4.1) as compared with AB and BB genotypes.

CONCLUSION

GSTM1 null, GSTT1 null, and GSTM3*AB genotypes may confer higher susceptibility to cervical cancer and cancer risk because at-risk genotypes are additive. Tobacco usage by carriers of GSTM3*AA has enhanced the risk of cervical cancer as compared with nonusers.

Care centre visits to married people living with HIV: an indicator for measuring AIDS-related stigma & discrimination

We tested whether observation of the presence and relationship of attendants (i.e. those that accompany upon admission) and visitors to a sample of 230 (128 male, 102 female) married HIV-positive people in an HIV care centre provides an indicator of caregiving, AIDS-related stigma and discrimination. Sensitivity to gender, location (urban vs. rural), age (<35 yrs vs. >35) and source of infection (spouse vs. non-spouse) were factors considered to modulate AIDS-related stigma and assess discrimination. HIV-positive people were accompanied by their spouse (53%), mother (14%), father (7%), with only 7% attending alone. Immediate family most commonly accompanied on admission (80%), but visitors were mainly from the 'extended' family (32%) with many receiving no visitors (48%). Females (11%) were more likely than males to attend alone (11% vs. 4%; p<0.05). No effect of location, age or infector was obtained. Females were more likely to be visited by their mother (14% vs. 6%; p<0.01) and non-immediate family (39% vs. 27%; p<0.05) than males were. In contrast, fathers (0% vs. 6%; p <0.05) and spouses were less likely (3% vs. 10%; p<0.05) to visit females than males. No effect of location or age upon visitation was obtained. Non-spouse infected persons were less likely than spouse-infected to be visited by their spouse (3% vs. 10%; p<0.05) but more likely to receive 'extended' family visitation (43% vs. 24%; p<0.01). Spouse-infected persons had a higher rate of no visitors than persons not infected by their spouse (54% vs. 40%; p<0.05). Observation of the presence and relationship of attendants and visitors to HIV-positive people has potential as an indicator of caregiving AIDS-related stigma and discrimination. The measure appears particularly sensitive to the gender of the HIV-positive person. Such a measure may aid healthcare professionals to focus resources such as relational counselling upon the family and close friends of people experiencing AIDS-related stigma and discrimination, with the aim of improving the provision of care within the community.

Sequence analysis of E/NS1 gene junction of dengue virus type 2 isolated in Brunei

A preliminary study of dengue infection in Brunei between 2005 and 2006 showed that dengue 2 was the predominant serotype. A total of five DEN-2 isolates were isolated and maintained in the mosquito cell-line, albopictus C6/36. The sequence spanning the envelope and non-structural protein 1 (E/NS1) junction (positions 2311 to 2550) of the isolates were determined and analysed at the amino acid and nucleotide levels. Alignment of the 240 nucleotide sequences among the five isolates showed changes occurring at 7 positions (2.9%) of the region. All but one nucleotide substitution (position 2319, amino acid 742 V --> F) were found at the 3rd position of the codons and were silent mutations. Amino acid homology ranged from 98% to 100%. Sequence divergence of the Brunei isolates varied from 5% to 6.6% compared with dengue-2 prototype New Guinea C strain. Comparison of the Brunei DEN-2 isolates with sixty-five other strains placed them in a cluster containing Indonesian strains isolated in 1973, 1978 and 2004 and Malaysian strains isolated in 1996, 1998 and 1999 in genotype group IV.

Dengue virus infection and immune response in humanized RAG2(-/-)gamma(c)(-/-) (RAG-hu) mice

Dengue viral (DENV) pathogenesis and vaccine studies are hampered by the lack of an ideal animal model mimicking human disease and eliciting an adaptive human immune response. Although currently available animal models have been very useful in dissecting some key aspects of disease pathogenesis, a major limitation with these is the lack of a human immune response. In this study, we sought to overcome this difficulty by utilizing a novel mouse model that permits multi-lineage human hematopoiesis and immune response following transplantation with human hematopoietic stem cells. To generate immunocompetent humanized mice, neonatal RAG2(-/-)gamma(c)(-/-) mice were xenografted with human CD34+ hematopoietic stem cells, resulting in de novo development of major functional cells of the human adaptive immune system. To evaluate susceptibility to dengue viral infection, humanized mice were challenged with DEN-2 serotype. Viremia lasting up to 3 weeks was detected in infected mice with viral titers reaching up to 10(6.3) RNA copies/ml. Fever characteristic of dengue was also noted in infected mice. Presence of human anti-dengue antibodies was evaluated using an antibody capture ELISA. Anti-dengue IgM was first detected by 2 weeks post-infection followed by IgG at 6 weeks. Sera from some of the infected mice were also found to be capable of dengue virus neutralization. Infected mouse sera showed reactivity with the viral envelope and capsid proteins in immunoprecipitation assay. These results demonstrate for the first time that humanized mice are capable of dengue viral primary human immune responses thus paving the way for new dengue immunopathogenesis and vaccine studies.

A preliminary study of dengue infection in Brunei

The purpose of this study was to examine the extent of dengue infection in Brunei and to determine the predominant serotype circulating in the country. The study generated useful epidemiological data on dengue infection in Brunei. A total of 271 samples from patients suspected of having dengue infections were selected and analyzed. All patients were seen in clinics and hospitals in Brunei. The samples were collected from April 2005 to April 2006 and transported to the WHO Collaborating Centre for Arbovirus Reference and Research, University of Malaya, Malaysia. The following tests were used to achieve the objectives: in-house IgM-capture enzyme-linked immunosorbent assay, virus isolation in mosquito albopictus cell line (C6/36), and viral RNA detection and serotyping by reverse transcriptase-polymerase chain reaction (RT-PCR). The results show that 45 people were positive for dengue-specific IgM (27 males and 18 females), while RT-PCR detected dengue viral RNA in 12 patients, 3 identified as DEN-1 and 9 as DEN-2. Dengue virus was isolated from 6 patients using the C6/36 cell line; 3 were DEN-2 isolates and 3 were DEN-1 isolates. These data show that dengue virus is circulating in Brunei and the predominant infecting serotype for that period was DEN-2 followed by DEN-1. This study is the first to report the detection and isolation of dengue virus from Brunei using RT-PCR and culture in the C6/36 albopictus mosquito cell line.

Cross-reactive T-cell responses to the nonstructural regions of dengue viruses among dengue fever and dengue hemorrhagic fever patients in Malaysia

Dengue virus infections are a major cause of morbidity and mortality in tropical and subtropical areas in the world. Attempts to develop effective vaccines have been hampered by the lack of understanding of the pathogenesis of the disease and the absence of suitable experimental models for dengue viral infection. The magnitude of T-cell responses has been reported to correlate with dengue disease severity. Sixty Malaysian adults with dengue viral infections were investigated for their dengue virus-specific T-cell responses to 32 peptides antigens from the structural and nonstructural regions from a dengue virus isolate. Seventeen different peptides from the C, E, NS2B, NS3, NS4A, NS4B, and NS5 regions were found to evoke significant responses in a gamma interferon enzyme-linked immunospot (ELISPOT) assay of samples from 13 selected patients with dengue fever (DF) and dengue hemorrhagic fever (DHF). NS3 and predominantly NS3(422-431) were found to be important T-cell targets. The highest peaks of T-cell responses observed were in responses to NS3(422-431) and NS5(563-571) in DHF patients. We also found almost a sevenfold increase in T-cell response in three DHF patients compared to three DF patient responses to peptide NS3(422-431). A large number of patients' T cells also responded to the NS2B(97-106) region. The ELISPOT analyses also revealed high frequencies of T cells that recognize both serotype-specific and cross-reactive dengue virus antigens in patients with DHF.

Rapid detection, serotyping and quantitation of dengue viruses by TaqMan real-time one-step RT-PCR

The use of the polymerase chain reaction (PCR) in molecular diagnosis is now accepted worldwide and has become an essential tool in the research laboratory. In the laboratory, a rapid detection, serotyping and quantitation, one-step real-time RT-PCR assay was developed for dengue virus using TaqMan probes. In this assay, a set of forward and reverse primers were designed targeting the serotype conserved region at the NS5 gene, at the same time flanking a variable region for all four serotypes which were used to design the serotype-specific TaqMan probes. This multiplex one-step RT-PCR assay was evaluated using 376 samples collected during the year 2003. These groups included RNA from prototype dengue virus (1-4), RNA from acute serum from which dengue virus was isolated, RNA from tissue culture supernatants of dengue virus isolated, RNA from seronegative acute samples (which were culture and IgM negative) and RNA from samples of dengue IgM positive sera. The specificity of this assay was also evaluated using a panel of sera which were positive for other common tropical disease agents including herpes simplex virus, cytomegalovirus, measles virus, varicella-zoster virus, rubella virus, mumps virus, WWF, West Nile virus, Japanese encephalitis virus, S. typhi, Legionella, Leptospira, Chlamydia, and Mycoplasma. The sensitivity, specificity and real-time PCR efficiency of this assay were 89.54%, 100% and 91.5%, respectively.

Inhibitory potential of Quercus lusitanica extract on dengue virus type 2 replication

This study reports the in vitro inhibitory potential of crude extract of Quercus lusitanica (Q. lusitanica) seeds on the replication of dengue virus type 2 (DEN-2). In vitro antiviral activity of Q. lusitanica extract, assessed in C6/36 cells (cloned cells of Aedes albopictus larvae) employing a virus inhibition assay, showed dose-dependent inhibition. The Q. lusitanica extract at its maximum non-toxic concentration of 0.25 mg/ml completely inhibited 10-1,000 TCID50 of virus, as indicated by the absence of cytopathic effect (CPE). The low dose of Q. lusitanica (0.032 mg/ml) showed 100% inhibition with 10 TCID50 of virus, but only 50% and 25% inhibition with 100 and 1,000 TCID50, respectively. The NS1 is a glycoprotein present in all flaviviruses and appears essential for virus viability. To further evaluate Q. lusitanica extract as an antiviral compound, we investigated the effect of Q. lusitanica extract on the NS1 protein expression of infected C6/36 cells through proteomics technique. The result showed downregulation of NS1 protein expression of infected C6/36 cells after treatment with this extract. In conclusion, we found that Q. lusitanica extract has a good inhibitory effect on the replication of dengue virus type 2, both in conventional cell culture and proteomics technique.

Negative cross-reactivity of rabbit anti-Malassezia furfur antibodies with other yeasts

Anti-Malassezia furfur monospecific polyclonal antibodies was produced by repeated immunization of rabbit with Malassezia furfur yeast cells mixed with Freud adjuvant. The antibody titres of respective rabbit's serum samples prior to and after each immunization against M. furfur were assayed by indirect immunofluorescence technique using the M. furfur whole yeast antigen fixed in Teflon coated slides. The highest anti-M. furfur antibody titre achieved was 1 in 1280 dilution. At 1:20 dilution, none of the respective serum samples taken at various stages of immunization gave positive immunofluorescent staining against any of the other species of yeasts tested in this study. Anti-M. furfur monospecific polyclonal antibodies produced in rabbit in this study has the potential for diagnostic application in immunohistochemical detection of M. furfur in human tissues.