Phylogenetic, genealogical and population relationships of Chrysomya bezziana, the Old World screwworm fly (OWSF), were inferred from DNA sequences of mitochondrial cytochrome b (cyt b), nuclear elongation factor-1α (EF-1α) and nuclear white eye colour (white), using sequences of Chrysomya megacephala and Chrysomya rufifacies as outgroups. Cyt b (717bp, 754 specimens), EF-1α (361bp, 256 specimens) and white (577bp, 242 specimens) were analysed from up to two African and nine Asian countries, including 10 Indonesian islands. We show that OWSF occurs as distinctive African and Asian lineages based on cyt b and white, and that there is a marked differentiation between Sumatran and Javan populations in Indonesia, supported by the genealogy and analysis of molecular variance of cyt b alone. Four cyt b sub-lineages are recognised in Asia: only 2.1 occurs on the Asian mainland, from Yemen to Peninsular Malaysia; only 2.2, 2.3 and 2.4 occur in central Indonesia; 2.4 predominates on New Guinea; and 2.1 co-occurs with others only on Sumatra in western Indonesia. This phylogeography and the genetic distances between cyt b haplotypes indicate pre-historic, natural dispersal of OWSF eastwards into Indonesia and other Malesian islands, followed by vicariant evolution in New Guinea and central Indonesia. OWSF is absent from Australia, where there is surveillance for importation or natural invasion. Judged by cyt b haplotype markers, there is currently little spread of OWSF across sea barriers, despite frequent shipments of Australian livestock through Indonesian seas to the Middle East Gulf region. These findings will inform plans for integrated pest management, which could be applied progressively, for example starting in East Nusa Tenggara (central Indonesia) where OWSF has regional cyt b markers, and progressing westwards to Java where any invasion from Sumatra is unlikely. Cyt b markers would help identify the source of any re-emergence in treated areas.
The objective of this study was to determine the expression and transferability of tetracycline and erythromycin resistance among 188 MRSA strains from a Malaysian tertiary hospital. The minimum inhibitory concentrations (MICs) for oxacillin, erythromycin, tetracycline and ciprofloxacin ranged from 4 to 512 μg/ml, 0.25 to 256 μg/ml, 0.5 to 256 μg/ml and 0.5 to 512 μg/ml, respectively. Tetracycline-resistant strains showed co-resistance towards ciprofloxacin and erythromycin. There was a significant increase (P<0.05) of high-level tetracycline (≥MIC 256 μg/ml) and erythromycin (≥MIC 128 μg/ml) resistant strains in between the years 2003 and 2008. All erythromycin-resistant strains harboured ermA or ermC gene and all tetracycline-resistant strains harboured tetM or tetK gene. The blaZ was detected in all MRSA strains, whereas ermA, tetM, ermC, tetK and msrA genes were detected in 157 (84%), 92 (49%), 40 (21%), 39 (21%) and 4 (2%) MRSA strains, respectively. The blaZ, tetM, ermC and tetK genes were plasmid-encoded, with ermC gene being easily transmissible. Tn5801-like transposon was present in 78 tetM-positive strains. ermA and tetM genes were the most prevalent erythromycin and tetracycline resistance determinants, respectively, in MRSA strains. The association of resistance genes with mobile genetic elements possibly enhances the spread of resistant traits in MRSA.
This paper proposes a new mixed training algorithm consisting of error backpropagation (EBP) and variable structure systems (VSSs) to optimize parameter updating of neural networks. For the optimization of the number of neurons in the hidden layer, a new term based on the output of the hidden layer is added to the cost function as a penalty term to make optimal use of hidden units related to weights corresponding to each unit in the hidden layer. VSS is used to control the dynamic model of the training process, whereas EBP attempts to minimize the cost function. In addition to the analysis of the imposed dynamics of the EBP technique, the global stability of the mixed training methodology and constraints on the design parameters are considered. The advantages of the proposed technique are guaranteed convergence, improved robustness, and lower sensitivity to initial weights of the neural network.
The presence of multipotent human limbal stromal cells resembling mesenchymal stromal cells (MSC) provides new insights to the characteristic of these cells and its therapeutic potential. However, little is known about the expression of stage-specific embryonic antigen 4 (SSEA-4) and the embryonic stem cell (ESC)-like properties of these cells. We studied the expression of SSEA-4 surface protein and the various ESC and MSC markers in the ex vivo cultured limbal stromal cells. The phenotypes and multipotent differentiation potential of these cells were also evaluated.
Recently we reported experimental and simulation results on an increase in resonance frequency of a SAW resonator caused by mass loading of micropillars made of SU-8, attached normal to the surface of the resonator. We concluded that SAW resonator and the SU-8 micropillars in unison form a system of coupled resonators. We have now extended this work and performed a finite element method simulation to study the resonance frequency characteristics of the SAW-based coupled resonator. In this paper we report the effect of the resonance frequency of the micropillars on the resonance frequency of the system of coupled resonators, and observe the coupling of micropillar resonance and the propagating SAW as described in the well known Dybwad system of coupled resonators.
MeSH terms: Acoustics; Vibration; Finite Element Analysis
Quorum sensing controls the virulence determinants in most proteobacteria. In this work, the hexane, chloroform and methanol extracts of an Ayurveda spice, namely clove (Syzygium aromaticum), shown anti-quorum sensing activity. Hexane and methanol extracts of clove inhibited the response of C. violaceum CV026 to exogenously supplied N-hexanoylhomoserine lactone, in turn preventing violacein production. Chloroform and methanol extracts of clove significantly reduced bioluminescence production by E. coli [pSB1075] grown in the presence of N-(3-oxododecanoyl)-L-homoserine lactone. We demonstrated that clove extract inhibited quorum sensing-regulated phenotypes in Pseudomonas aeruginosa PA01, including expression of lecA::lux (by hexane extract), swarming (maximum inhibition by methanol extract), pyocyanin (maximum inhibition by hexane extract). This study shows that the presence of natural compounds that exhibit anti-quorum sensing activity in the clove extracts may be useful as the lead of anti-infective drugs.
Fault Tolerant Control (FTC) systems are crucial in industry to ensure safe and reliable operation, especially of motor drives. This paper proposes the use of multiple controllers for a FTC system of an induction motor drive, selected based on a switching mechanism. The system switches between sensor vector control, sensorless vector control, closed-loop voltage by frequency (V/f) control and open loop V/f control. Vector control offers high performance, while V/f is a simple, low cost strategy with high speed and satisfactory performance. The faults dealt with are speed sensor failures, stator winding open circuits, shorts and minimum voltage faults. In the event of compound faults, a protection unit halts motor operation. The faults are detected using a wavelet index. For the sensorless vector control, a novel Boosted Model Reference Adaptive System (BMRAS) to estimate the motor speed is presented, which reduces tuning time. Both simulation results and experimental results with an induction motor drive show the scheme to be a fast and effective one for fault detection, while the control methods transition smoothly and ensure the effectiveness of the FTC system. The system is also shown to be flexible, reverting rapidly back to the dominant controller if the motor returns to a healthy state.
An N-acylhomoserine lactone (AHL)-degrading bacterial strain, L62, was isolated from a sample of fermentation brine of Chinese soya sauce by using rich medium agar supplemented with soya sauce (10% v/v). L62, a rod-shaped Gram positive bacterium with amylolytic activity, was phylogentically related to Bacillus sonorensis by 16S ribosomal DNA and rpoB sequence analyses. B. sonorensis L62 efficiently degraded N-3-oxohexanoyl homoserine lactone and N-octanoylhomoserine lactone. However, the aiiA homologue, encoding an autoinducer inactivation enzyme catalyzing the degradation of AHLs, was not detected in L62, suggesting the presence of a different AHL-degrading gene in L62. To the best of our knowledge, this is the first report of AHL-degrading B. sonorensis from soya sauce liquid state fermentation.
MeSH terms: Bacillus/physiology*; Fermentation*; Soy Foods*; Quorum Sensing*
Quorum sensing regulates bacterial virulence determinants, therefore making it an interesting target to attenuate pathogens. In this work, we screened edible, endemic plants in Malaysia for anti-quorum sensing properties. Extracts from Melicope lunu-ankenda (Gaertn.) T. G. Hartley, a Malay garden salad, inhibited response of Chromobacterium violaceum CV026 to N-hexanoylhomoserine lactone, thus interfering with violacein production; reduced bioluminescence expression of E. coli [pSB401], disrupted pyocyanin synthesis, swarming motility and expression of lecA::lux of Pseudomonas aeruginosa PAO1. Although the chemical nature of the anti-QS compounds from M. lunu-ankenda is currently unknown, this study proves that endemic Malaysian plants could serve as leads in the search for anti-quorum sensing compounds.
MeSH terms: Plant Extracts/pharmacology*; Rutaceae/chemistry*; Luminescence; Quorum Sensing/drug effects*
Underwater Wireless Sensor Networks (UWSNs) provide new opportunities to observe and predict the behavior of aquatic environments. In some applications like target tracking or disaster prevention, sensed data is meaningless without location information. In this paper, we propose a novel 3D centralized, localization scheme for mobile underwater wireless sensor network, named Reverse Localization Scheme or RLS in short. RLS is an event-driven localization method triggered by detector sensors for launching localization process. RLS is suitable for surveillance applications that require very fast reactions to events and could report the location of the occurrence. In this method, mobile sensor nodes report the event toward the surface anchors as soon as they detect it. They do not require waiting to receive location information from anchors. Simulation results confirm that the proposed scheme improves the energy efficiency and reduces significantly localization response time with a proper level of accuracy in terms of mobility model of water currents. Major contributions of this method lie on reducing the numbers of message exchange for localization, saving the energy and decreasing the average localization response time.
In a polymicrobial community, while some bacteria are communicating with neighboring cells (quorum sensing), others are interrupting the communication (quorum quenching), thus creating a constant arms race between intercellular communication. In the past decade, numerous quorum quenching enzymes have been found and initially thought to inactivate the signalling molecules. Though this is widely accepted, the actual roles of these quorum quenching enzymes are now being uncovered. Recent evidence extends the role of quorum quenching to detoxification or metabolism of signalling molecules as food and energy source; this includes "signalling confusion", a term coined in this paper to refer to the phenomenon of non-destructive modification of signalling molecules. While quorum quenching has been explored as a novel anti-infective therapy targeting, quorum sensing evidence begins to show the development of resistance against quorum quenching.
MeSH terms: Signal Transduction*; Bacterial Physiological Phenomena; Quorum Sensing*
We report the production and degradation of quorum sensing N-acyl-homoserine lactones by bacteria isolated from Malaysian montane forest soil. Phylogenetic analysis indicated that these isolates clustered closely to the genera of Arthrobacter, Bacillus and Pseudomonas. Quorum quenching activity was detected in six isolates of these three genera by using a series of bioassays and rapid resolution liquid chromatography analysis. Biosensor screening and high resolution liquid chromatography-mass spectrometry analysis revealed the production of N-dodecanoyl-L-homoserine lactone (C12-HSL) by Pseudomonas frederiksbergensis (isolate BT9). In addition to degradation of a wide range of N-acyl-homoserine lactones, Arthrobacter and Pseudomonas spp. also degraded p-coumaroyl-homoserine lactone. To the best of our knowledge, this is the first documentation of Arthrobacter and Pseudomonas spp. capable of degrading p-coumaroyl-homoserine lactone and the production of C12-HSL by P. frederiksbergensis.
MeSH terms: Base Sequence; Chromatography, Liquid; Malaysia; Soil Microbiology*; Mass Spectrometry; Trees*; Tropical Climate*; Biosensing Techniques; Polymerase Chain Reaction; DNA Primers; Bacterial Physiological Phenomena*; Quorum Sensing*
Adult freshwater snails Melanoides tuberculata (Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT₅₀) and concentrations (LC₅₀) were calculated. LT₅₀ and LC₅₀ increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC(50) values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59 mg L⁻¹, respectively. Cu was the most toxic metal to M. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration in M. tuberculata increases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC₅₀ values for metals for this species with those for other freshwater gastropods reveals that M. tuberculata is equally sensitive to metals.
Obesity and obesity-related complications are on the increase both in the developed and developing world. Since existing pharmaceuticals fail to come up with long-term solutions to address this issue, there is an ever-pressing need to find and develop new drugs and alternatives. Natural products, particularly medicinal plants, are believed to harbor potential antiobesity agents that can act through various mechanisms either by preventing weight gain or promoting weight loss amongst others. The inhibition of key lipid and carbohydrate hydrolyzing and metabolizing enzymes, disruption of adipogenesis, and modulation of its factors or appetite suppression are some of the plethora of targeted approaches to probe the antiobesity potential of medicinal plants. A new technology such as metabolomics, which deals with the study of the whole metabolome, has been identified to be a promising technique to probe the progression of diseases, elucidate their pathologies, and assess the effects of natural health products on certain pathological conditions. This has been applied to drug research, bone health, and to a limited extent to obesity research. This paper thus endeavors to give an overview of those plants, which have been reported to have antiobesity effects and highlight the potential and relevance of metabolomics in obesity research.
Eupatorium odoratum (EO) contains many biologically active compounds, the anticancer effects of which are not well documented. This study evaluates the cytotoxic effects and mechanism of action of EO extracts on MCF-7 and Vero cell lines. Evaluation of the cytotoxic activity using MTT assay, morphological alterations, and apoptosis were carried out. Autophagy was evaluated by LC3-A protein expression. Cytotoxic activity, membrane blebbing and ballooning at 24 hours, replacement by mass vacuolation, and double membrane vesicles mimicking autophagy and cell death were observed in the cancer cells. No apoptosis was observed by DNA fragmentation assay. Overexpression of LC3-A protein indicated autophagic cell death. Cell cycle analysis showed G0 and G2/M arrest. The Vero cells did not show significant cell death at concentrations <100 μg/mL. These results thus suggest that acetone and ethyl acetate extracts of EO induce cell death through induction of autophagy and hold potential for development as potential anticancer drugs.
Ultrahigh-molecular-weight polyethylene/high-density polyethylene (UHMWPE/HDPE) blends prepared using polyethylene glycol PEG as the processing aid and hydroxyapatite (HA) as the reinforcing filler were found to be highly processable using conventional melt blending technique. It was demonstrated that PEG reduced the melt viscosity of UHMWPE/HDPE blend significantly, thus improving the extrudability. The mechanical and bioactive properties were improved with incorporation of HA. Inclusion of HA from 10 to 50 phr resulted in a progressive increase in flexural strength and modulus of the composites. The strength increment is due to the improvement on surface contact between the irregular shape of HA and polymer matrix by formation of mechanical interlock. The HA particles were homogenously distributed even at higher percentage showed improvement in wetting ability between the polymer matrix and HA. The inclusion of HA enhanced the bioactivity properties of the composite by the formation of calcium phosphate (Ca-P) precipitates on the composite surface as proven from SEM and XRD analysis.
The cyclic AMP- (cAMP-) dependent protein kinase A signaling pathway is one of the major signaling pathways responsible for regulation of the morphogenesis and pathogenesis of several pathogenic fungi. To evaluate the role of this pathway in the plant pathogenic fungus, Colletotrichum gloeosporioides, the gene encoding the catalytic subunit of cAMP-dependent protein kinase A, CgPKAC, was cloned, inactivated, and the mutant was analyzed. Analysis of the Cgpkac mutant generated via gene replacement showed that the mutants were able to form appressoria; however, their formation was delayed compared to the wild type. In addition, the mutant conidia underwent bipolar germination after appressoria formation, but no appressoria were generated from the second germ tube. The mutants also showed reduced ability to adhere to a hydrophobic surface and to degrade lipids localized in the appressoria. Based on the number of lesions produced during a pathogenicity test, the mutant's ability to cause disease in healthy mango fruits was reduced, which may be due to failure to penetrate into the fruit. These findings indicate that cAMP-dependent protein kinase A has an important role in regulating morphogenesis and is required for pathogenicity of C. gloeosporioides.
MeSH terms: Base Sequence; Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors*; Cyclic AMP-Dependent Protein Kinases/metabolism; Cyclic AMP-Dependent Protein Kinases/chemistry; DNA Primers; Catalytic Domain; Colletotrichum/enzymology; Colletotrichum/pathogenicity*
Unspecialized cells that can renew themselves and give rise to multiple differentiated cell types are termed stem cells. The objective of this study was to characterize and investigate, through molecular and biochemical analyses, the stemness of cells derived from isolated mononucleated cells that originated from peripheral blood. The isolated mononucleated cells were separated according to their physical characteristics (adherent and suspension), after 4 to 7 days into a 14-day culturing period in complete medium. Our results revealed that adherent and suspension cells were positive for mesenchymal stem cell (MSC) and hematopoietic stem cell (HSC) markers, respectively. Differentiation of adherent cells into osteoblasts was associated with expression of the OPN gene and increasing ALP enzyme activity, while differentiation of suspension cells into osteoclasts was associated with expression of the TRAP gene and increasing TRAP enzyme activity. In conclusion, molecular and biochemical analyses showed that mononucleated cells consist of MSC (adherent) and HSC (suspension), and both cell types are able to differentiate into specialized cells from their respective lineage: osteoblast (MSC) and osteoclast (HSC).
MeSH terms: Adolescent; Adult; Base Sequence; Cell Differentiation; Cells, Cultured; Hematopoietic Stem Cells/cytology; Humans; Monocytes/cytology*; DNA Primers; Reverse Transcriptase Polymerase Chain Reaction; Gene Expression Profiling; Young Adult; Mesenchymal Stromal Cells/cytology
The demand for salinity-tolerant turfgrasses is increasing due to augmented use of effluent or low-quality water (sea water) for turf irrigation and the growing turfgrass industry in coastal areas. Experimental plants, grown in plastic pots filled with a mixture of river sand and KOSAS(R) peat (9 : 1), were irrigated with sea water at different dilutions imparting salinity levels of 0, 8, 16, 24, 32, 40, or 48 dS m⁻¹. Salinity tolerance was evaluated on the basis of leaf firing, shoot and root growth reduction, proline content, and relative water content. Paspalum vaginatum was found to be most salt tolerant followed by Zoysia japonica and Zoysia matrella, while Digitaria didactyla, Cynodon dactylon "Tifdwarf," and Cynodon dactylon "Satiri" were moderately tolerant. The results indicate the importance of turfgrass varietal selection for saline environments.
Background and Purpose. This study aimed to evaluate the wound healing activities of Aftamed and chlorine dioxide gels in streptozotocin-induced diabetic rats. Experimental Approach. Forty-eight Sprague Dawley rats were chosen for this study, divided into 4 groups. Diabetes was induced. Two-centimeter-diameter full-thickness skin excision wounds were created. Animals were topically treated twice daily. Groups 1, the diabetic control group, were treated with 0.2 mL of sterile distilled water. Group 2 served as a reference standard were treated with 0.2 mL of Intrasite gel. Groups 3 and 4 were treated with 0.2 mL of Aftamed and 0.2 mL of chlorine dioxide gels respectively. Granulation tissue was excised on the 10th day and processed for histological and biochemical analysis. The glutathione peroxidase ,superoxide dismutase activities and the malondialdehyde (MDA) levels were determined. Results. Aftamed-treated wounds exhibited significant increases in hydroxyproline, cellular proliferation, the number of blood vessels, and the level of collagen synthesis. Aftamed induced an increase in the free radical-scavenging enzyme activity and significantly reduced the lipid peroxidation levels in the wounds as measured by the reduction in the MDA level. Conclusions. This study showed that Aftamed gel is able to significantly accelerate the process of wound healing in diabetic rats.