Characterisation of ESBL/AmpC-Producing Enterobacteriaceae isolated from poultry farms in Peninsular Malaysia

Extended-spectrum beta-lactamases (ESBLs) and AmpC beta-lactamases (AmpCs)-producing Enterobacteriaceae have been increasingly reported and imposing significant threat to public. Livestock production industry might be the important source for clinically important ESBL-producing Enterobacteriaceae. This study aims to investigate the resistance profile, phenotypic ESBL production, beta-lactamase genes, virulence factors, and plasmid replicon types among 59 Enterobacteriaceae strains isolated from poultry faecal samples in Malaysia's commercial poultry farm. There were 38.7% and 32.3% of Escherichia coli resistant to cefotaxime and cefoxitin, respectively, while Klebsiellaspp. demonstrated resistance rate of 52.6% to both mentioned antimicrobials. Majority of the E. coli isolates carried blaTEM and blaCMY-2 group. blaSHV was the most prevalent gene detected in Klebsiellaspp., followed by blaDHA and blaTEM. Resistance to extended spectrum cephalosporin in our isolates was primarily mediated by plasmid mediated AmpC beta-lactamase such as CMY-2 group and DHA enzyme. The CTX-M genes were found in two ESBL-producing E. coli. IncF, IncI1, and IncN plasmids were most frequently detected in E. coli and Klebsiellaspp. The virulence factor, including EAST1 and pAA were identified at low frequency. This study highlights the poultry as a reservoir of resistance and virulence determinants and prevalence of plasmids in Enterobacteriaceae might drive their dissemination.

Trailing TRAIL Resistance in Human Breast Adenocarcinoma Cells with Trichostatin A and Zebularine

AIMS

The aim of this study was to sensitize the resistant breast adenocarcinoma cells towards Tumour Necrosis Factor-related Apoptosis-inducing Ligand (TRAIL)-induced apoptosis.

BACKGROUND

Breast cancer is a heterogeneous disease involving complex mechanisms. TRAIL is a potential anticancer candidate for targeted treatment due to its selective killing effects on neoplastic cells. Nonetheless, resistance occurs in many cancers either intrinsically or after multiple treatments.

OBJECTIVE

Therefore, this research investigated whether the combination of Trichostatin A (TSA) and Zebularine (Zeb) (TZ) followed by TRAIL (TZT) could sensitize the human breast adenocarcinoma cells towards apoptosis.

METHODS

The breast adenocarcinoma cells, MDA-MB-231, MCF-7 and E-MDA-MB-231 (E-cadherin re-expressed MDA-MB-231) were treated with TSA, Zeb, TZ, TRAIL and TZT. The cells were subjected to hematoxylin and eosin (H & E) staining and FITC-Annexin V/Propidium Iodide apoptosis detection prior to proteome profiling.

RESULTS

Based on morphological observation, apoptosis was induced in all cells treated with all treatment regimens though it was more evident for the TZT-treated cells. In the apoptosis detection analysis, TZ increased early apoptosis significantly in MDA-MB-231 and MCF-7 while TRAIL induced late apoptosis significantly in E-MDA-MB-231. Based on the proteome profiling on MDA-MB-231, TRAIL R2 and Fas expression was increased. For E-MDA-MB- 231, down-regulation of catalase, paraoxonase-2 (PON2), clusterin, an inhibitor of apoptosis proteins (IAPs) and cell stress proteins validated the notion that E-cadherin re-expression enhances TZT anti-cancer efficacy. Similar trend was observed in MCF-7 whereby TZT treatment down-regulated the anti-apoptotic catalase and PON2, increased the proapoptotic, B cell lymphoma 2 (Bcl-2)-associated agonist of cell death (Bad) and Bcl-2-associated X (Bax), second mitochondria-derived activator of caspase (SMAC) and HtrA serine peptidase 2 (HTRA2) as well as TRAIL receptors (TRAIL R1 and TRAIL R2).

CONCLUSION

TZ treatment serves as an efficient treatment regimen for MDA-MB-231 and MCF-7, while TRAIL serves as a better treatment option for E-MDA-MB-231. Therefore, future studies on E-cadherin's positive regulatory role in TRAIL-induced apoptosis are warranted.

Vacuolar Processing Enzymes Modulating Susceptibility Response to Fusarium oxysporum f. sp. cubense Tropical Race 4 Infections in Banana

Fusarium oxysporum f. sp. cubense tropical race 4 (FocTR4) is a destructive necrotrophic fungal pathogen afflicting global banana production. Infection process involves the activation of programmed cell death (PCD). In this study, seven Musa acuminata vacuolar processing enzyme (MaVPE1-MaVPE7) genes associated with PCD were successfully identified. Phylogenetic analysis and tissue-specific expression categorized these MaVPEs into the seed and vegetative types. FocTR4 infection induced the majority of MaVPE expressions in the susceptible cultivar "Berangan" as compared to the resistant cultivar "Jari Buaya." Consistently, upon FocTR4 infection, high caspase-1 activity was detected in the susceptible cultivar, while low level of caspase-1 activity was recorded in the resistant cultivar. Furthermore, inhibition of MaVPE activities via caspase-1 inhibitor in the susceptible cultivar reduced tonoplast rupture, decreased lesion formation, and enhanced stress tolerance against FocTR4 infection. Additionally, the Arabidopsis VPE-null mutant exhibited higher tolerance to FocTR4 infection, indicated by reduced sporulation rate, low levels of H₂O₂ content, and high levels of cell viability. Comparative proteomic profiling analysis revealed increase in the abundance of cysteine proteinase in the inoculated susceptible cultivar, as opposed to cysteine proteinase inhibitors in the resistant cultivar. In conclusion, the increase in vacuolar processing enzyme (VPE)-mediated PCD played a crucial role in modulating susceptibility response during compatible interaction, which facilitated FocTR4 colonization in the host.

Pentacyclic and hexacyclic cucurbitacins from Elaeocarpuspetiolatus

Four undescribed cucurbitacins, designated as petiolaticins A-D, and four known cucurbitacins were isolated from the bark and leaves of Elaeocarpus petiolatus (Jack) Wall. Their chemical structures were elucidated based on detailed analyses of the NMR and MS data. The absolute configuration of petiolaticin A was also determined by X-ray diffraction analysis. Petiolaticin A represents a cucurbitacin derivative incorporating a 3,4-epoxyfuranyl-bearing side chain, while petiolaticin B possesses a furopyranyl unit fused to the tetracyclic cucurbitane core structure. Petiolaticins A, B, and D were evaluated in vitro against a panel of human breast, pancreatic, and colorectal cancer cell lines. Petiolaticin A exhibited the greatest cytotoxicity against the MDA-MB-468, MDA-MB-231, MCF-7, and SW48 cell lines (IC₅₀ 7.4, 9.2, 9.3, and 4.6 μM, respectively). Additionally, petiolaticin D, 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one, and 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one 3-O-β-_D-glucopyranoside were tested for their ability to inhibit cell entry of a pseudotyped virus bearing the hemagglutinin envelope protein of a highly pathogenic avian influenza virus. Petiolaticin D showed the highest inhibition (44.3%), followed by 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one (21.0%), and 16α,23α-epoxy-3β,20β-dihydroxy-10αH,23βH-cucurbit-5,24-dien-11-one 3-O-β-_D-glucopyranoside showed limited inhibition (9.0%). These preliminary biological assays have demonstrated that petiolaticins A and D possess anticancer and antiviral properties, respectively, which warrant for further investigations.

A graphene-based dengue immunosensor using plant-derived envelope glycoprotein domain III (EDIII) as the novel probe antigen

The envelope glycoprotein domain III (EDIII) of dengue virus (DENV) has been recognised as the antigenic region responsible for receptor binding. In the present work, we have proposed a novel immunosensor constructed on a graphene-coated screen-printed carbon electrode (SPCE) using plant-derived EDIII as the probe antigen to target DENV IgG antibodies. The developed immunosensor demonstrated high sensitivity towards DENV IgG within a wide linear working range (125-2000 ng mL^-1) under the optimised sensing conditions. The limit of detection was determined to be 22.5 ng mL^-1. The immunosensor also showed high specificity towards DENV IgG, capable of differentiating DENV IgG from the antibodies of other infectious diseases including the similarly structured Zika virus (ZIKV). The ability of the immunosensor to detect dengue antibodies in serum samples was also verified by conducting tests on mouse serum samples. The proposed immunosensor was able to provide a binary (positive/negative) response towards the serum samples comparable to the conventional enzyme-linked immunosorbent assay (ELISA), indicating promising potential for realistic applications.

The TRAIL to cancer therapy: Hindrances and potential solutions

Apoptosis is an ordered and orchestrated cellular process that occurs in physiological and pathological conditions. Resistance to apoptosis is a hallmark of virtually all malignancies. Despite being a cause of pathological conditions, apoptosis could be a promising target in cancer treatment. Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), also known as Apo-2 ligand (Apo2L), is a member of TNF cytokine superfamily. It is a potent anti-cancer agent owing to its specific targeting towards cancerous cells, while sparing normal cells, to induce apoptosis. However, resistance occurs either intrinsically or after multiple treatments which may explain why cancer therapy fails. This review summarizes the apoptotic mechanisms via extrinsic and intrinsic apoptotic pathways, as well as the apoptotic resistance mechanisms. It also reviews the current clinically tested recombinant human TRAIL (rhTRAIL) and TRAIL receptor agonists (TRAs) against TRAIL-Receptors, TRAIL-R1 and TRAIL-R2, in which the outcomes of the clinical trials have not been satisfactory. Finally, this review discusses the current strategies in overcoming resistance to TRAIL-induced apoptosis in pre-clinical and clinical settings.

Potentiation of in vitro apoptotic effects of δ-Tocotrienol and Jerantinine A on human lung adenocarcinoma cells

Introduction: The apoptotic effects of single-compound and combined sub-effective concentrations of δ-tocotrienol and jerantinine A on human lung adenocarcinoma (A549) cells were investigated. Methods: Assays including cell viability, histochemical and immunofluorescence staining techniques, flow cytometry and enzyme activity were used. Results: The combination of δ-tocotrienol with jerantinine A at sub-effective concentrations induced a synergistic effect and improved selective toxicity towards cancerous A549 cells over normal lung fibroblast (MRC5) cells compared to the single-compound jerantinine. Morphological features of apoptosis were evident on treated A549 cells. Combined sub-effective concentrations of δ-tocotrienol with jerantinine A induced a predominantly G2/M cell cycle arrest and characterised by a disruption of microtubular networks mediated via caspase 8, 9 and 3 enzymatic activities. Conclusion: These findings demonstrated improved potency in vitro and reduced dose-related toxicity of jerantinine A to normal cells through prospective combined treatment between low-concentration δ-tocotrienol and jerantinine A for lung cancer.

Virucidal activity of Garcinia parvifolia leaf extracts in animal cell culture

Background

Garcinia species contain bioactive compounds such as flavonoids, xanthones, triterpernoids, and benzophenones with antibacterial, antifungal, anti-inflammatory, and antioxidant activities. In addition, many of these compounds show interesting biological properties such as anti-human immunodeficiency virus activity. Garcinia parvifolia is used in traditional medicine. Currently, the antiviral activity of G. parvifolia is not known.

Methods

This study was conducted to determine the effects of ethyl acetate (45 L Ea), ethanol (45 L Et), and hexane (45 L H) leaf extracts of G. parvifolia on the infectivity of pseudorabies virus (PrV) in Vero cells. The antiviral effects of the extracts were determined by cytopathic effect (CPE), inhibition, attachment, and virucidal assays.

Results

The 50% cytotoxicity concentration (CC₅₀) values obtained were 237.5, 555.0, and < 1.25 μg/mL for 45 L Ea, 45 L Et, and 45 L H, respectively. The 45 L Ea showed the greatest viral inhibition potency of 75% at 125 μg/mL. Both 45 L Ea and 45 l Et caused 100% residual viral inhibition at 250 μg/mL. The selectivity index values for 45 L Ea, 45 L Et, and 45 L H were 2.65, 1.75, and 0.10 showing that 45 L Ea had the greatest antiviral activity among the three extracts.

Conclusion

This study showed that ethyl acetate is the best solvent to be used to obtain extract from G. parvifolia leaves with potent antiviral activities.

Cis-9, Trans-11 Conjugated Linoleic Acid Reduces Phosphoenolpyruvate Carboxykinase Expression and Hepatic Glucose Production in HepG2 Cells

Dysregulated hepatic gluconeogenesis is a hallmark of insulin resistance and type 2 diabetes mellitus (T2DM). Although existing drugs have been proven to improve gluconeogenesis, achieving this objective with functional food is of interest, especially using conjugated linoleic acid (CLA) found in dairy products. Both cis-9, trans-11 (c9,t11) and trans-10, cis-12 (t10,c12) isomers of CLA were tested in human (HepG2) and rat (H4IIE) hepatocytes for their potential effects on gluconeogenesis. The hepatocytes exposed for 24 h with 20 μM of c9,t11-CLA had attenuated the gluconeogenesis in both HepG2 and H4IIE by 62.5% and 80.1%, respectively. In contrast, t10,c12-CLA had no effect. Of note, in HepG2 cells, the exposure of c9,t11-CLA decreased the transcription of gluconeogenic enzymes, cytosolic phosphoenolpyruvate carboxykinase (PCK1) by 87.7%, and glucose-6-phosphatase catalytic subunit (G6PC) by 38.0%, while t10,c12-CLA increased the expression of G6PC, suggesting the isomer-specific effects of CLA on hepatic glucose production. In HepG2, the peroxisome proliferator-activated receptor (PPAR) agonist, rosiglitazone, reduced the glucose production by 72.9%. However, co-administration of c9,t11-CLA and rosiglitazone neither exacerbated nor attenuated the efficacy of rosiglitazone to inhibit glucose production; meanwhile, t10,c12-CLA abrogated the efficacy of rosiglitazone. Paradoxically, PPARγ antagonist GW 9662 also led to 70.2% reduction of glucose production and near undetectable PCK1 expression by abrogating CLA actions. Together, while the precise mechanisms by which CLA isomers modulate hepatic gluconeogenesis directly or via PPAR warrant further investigation, our findings establish that c9,t11-CLA suppresses gluconeogenesis by decreasing PEPCK on hepatocytes.

Fabrication and preliminary in vitro evaluation of ultraviolet-crosslinked electrospun fish scale gelatin nanofibrous scaffolds

This study aimed to explore a potential use of fish scale-derived gelatin nanofibrous scaffolds (GNS) in tissue engineering due to their biological and economical merits. Extraction of gelatin was achieved via decalcification, sonication and lyophilization of mixed fish scales. To fabricate nano-scale architecture of scaffolds analogous to natural extracellular matrix, gelatin was rendered into nanofibrous matrices through 6-h electrospinning, resulting in the average diameter of 48 ± 12 nm. In order to improve the water-resistant ability while retaining their biocompatibility, GNS were physically crosslinked with ultraviolet (UV) irradiation for 5 min (UGN5), 10 min (UGN10) and 20 min (UGN20). On average, the diameter of nanofibers increased by 3 folds after crosslinking, however, Fourier transform infrared spectroscopy analysis confirmed that no major alterations occurred in the functional groups of gelatin. A degradation assay showed that UGN5 and UGN10 scaffolds remained in minimum essential medium for 14 days, while UGN20 scaffolds degraded completely after 10 days. All UGN scaffolds promoted adhesion and proliferation of human keratinocytes, HaCaT, without causing an apparent cytotoxicity. UGN5 scaffolds were shown to stimulate a better growth of HaCaT cells compared to other scaffolds upon 1 day of incubation, whereas UGN20 had a long-term effect on cells exhibiting 25% higher cell proliferation than positive control after 7 days. In the wound scratch assay, UGN5 scaffolds induced a rapid cell migration closing up to 79% of an artificial wound within 24 h. The current findings provide a new insight of UGN scaffolds to serve as wound dressings in the future. In the wound scratch assay, UGN5 induced a rapid cell migration closing up to 79% of an artificial wound within 24 h.

Epitope Presentation of Dengue Viral Envelope Glycoprotein Domain III on Hepatitis B Core Protein Virus-Like Particles Produced in Nicotiana benthamiana

Dengue fever is currently ranked as the top emerging tropical disease, driven by increased global travel, urbanization, and poor hygiene conditions as well as global warming effects which facilitate the spread of Aedes mosquitoes beyond their current distribution. Today, more than 100 countries are affected most of which are tropical Asian and Latin American nations with limited access to medical care. Hence, the development of a dengue vaccine that is dually cost-effective and able to confer a comprehensive protection is ultimately needed. In this study, a consensus sequence of the antigenic dengue viral glycoprotein domain III (cEDIII) was used aiming to provide comprehensive coverage against all four circulating dengue viral serotypes and potential clade replacement event. Utilizing hepatitis B tandem core technology, the cEDIII sequence was inserted into the immunodominant c/e1 loop region so that it could be displayed on the spike structures of assembled particles. The tandem core particles displaying cEDIII epitopes (tHBcAg-cEDIII) were successfully produced in Nicotiana benthamiana via Agrobacterium-mediated transient expression strategy to give a protein of ∼54 kDa, detected in both soluble and insoluble fractions of plant extracts. The assembled tHBcAg-cEDIII virus-like particles (VLPs) were also visualized from transmission electron microscopy. These VLPs had diameters that range from 32 to 35 nm, presenting an apparent size increment as compared to tHBcAg control particles without cEDIII display (namely tEL). Mice immunized with tHBcAg-cEDIII VLPs showed a positive seroconversion to cEDIII antigen, thereby signifying that the assembled tHBcAg-cEDIII VLPs have successfully displayed cEDIII antigen to the immune system. If it is proven to be successful, tHBcAg-cEDIII has the potential to be developed as a cost-effective vaccine candidate that confers a simultaneous protection against all four infecting dengue viral serotypes.

Tocotrienols Modulate a Life or Death Decision in Cancers

Malignancy often arises from sophisticated defects in the intricate molecular mechanisms of cells, rendering a complicated molecular ground to effectively target cancers. Resistance toward cell death and enhancement of cell survival are the common adaptations in cancer due to its infinite proliferative capacity. Existing cancer treatment strategies that target a single molecular pathway or cancer hallmark fail to fully resolve the problem. Hence, multitargeted anticancer agents that can concurrently target cell death and survival pathways are seen as a promising alternative to treat cancer. Tocotrienols, a minor constituent of the vitamin E family that have previously been reported to induce various cell death mechanisms and target several key survival pathways, could be an effective anticancer agent. This review puts forward the potential application of tocotrienols as an anticancer treatment from a perspective of influencing the life or death decision of cancer cells. The cell death mechanisms elicited by tocotrienols, particularly apoptosis and autophagy, are highlighted. The influences of several cell survival signaling pathways in shaping cancer cell death, particularly NF-κB, PI3K/Akt, MAPK, and Wnt, are also reviewed. This review may stimulate further mechanistic researches and foster clinical applications of tocotrienols via rational drug designs.

Synergistic Apoptotic Effects of Tocotrienol Isomers and Acalypha wilkesiana on A549 and U87MG Cancer Cells

Recent studies suggested that combined treatment approaches can be used to improve anticancer potency and circumvent the limitations of high-dose tocotrienols administration. Acalypha wilkesiana is a medicinal plant that has been used as an adjunct treatment for cancers in traditional medicine. Herein, the effects of single and combined treatments of β-, γ- and δ-tocotrienols and ethyl acetate extract (9EA) of Acalypha wilkesiana on lung (A549) and brain (U87MG) cancer cells were investigated. γ- and δ-tocotrienols exhibited higher potent antiproliferative effects against A549 (12.1 μg/ml and 13.6 μg/ml) and U87MG cells (3.3 μg/ml and 5.2 μg/ml) compared to β-tocotrienols (9.4 μg/ml and 92.4 μg/ml), respectively. Whereas, 9EA induced potent antiproliferative effects against U87MG cells only (2.0 μg/ml). Combined treatments of tocotrienols and 9EA induced a synergistic growth inhibition with up to 8.4-fold reduction in potent doses of β-, γ- and δ-tocotrienols on A549 cells. Apoptotic features were also evidenced on A549 cells receiving single and combined treatments. The synergism may greatly improve the therapeutic outcome for lung cancer.

One-step green hydrothermal synthesis of biocompatible graphene/TiO2 nanocomposites for non-enzymatic H2O2 detection and their cytotoxicity effects on human keratinocyte and lung fibroblast cells

A simple, safe, and efficient approach to synthesise graphene/titanium dioxide (G/TiO₂) nanocomposites with potential in electrochemical sensing application and relatively good biocompatibility to human cells.

Using transgenic plants and modified plant viruses for the development of treatments for human diseases

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Concept of plant-based biofactories for therapeutics and biologics.

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Industrial preference of transient expression system — agroinfiltration.

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Advancement of virus-like particles from epitope presentation to nanomedicine.

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Recent progress of plant-made therapeutics and biologics against human diseases.

Production of proteins in plants for human health applications has become an attractive strategy attributed by their potentials for low-cost production, increased safety due to the lack of human or animal pathogens, scalability and ability to produce complex proteins. A major milestone for plant-based protein production for use in human health was achieved when Protalix BioTherapeutics produced taliglucerase alfa (Elelyso^®) in suspension cultures of a transgenic carrot cell line for the treatment of patients with Gaucher's disease, was approved by the USA Food and Drug Administration in 2012. In this review, we are highlighting various approaches for plant-based production of proteins and recent progress in the development of plant-made therapeutics and biologics for the prevention and treatment of human diseases.

Enhancement of apoptotic activities on brain cancer cells via the combination of γ-tocotrienol and jerantinine A

BACKGROUND

γ-Tocotrienol, a vitamin E isomer possesses pronounced in vitro anticancer activities. However, the in vivo potency has been limited by hardly achievable therapeutic levels owing to inefficient high-dose oral delivery which leads to subsequent metabolic degradation. Jerantinine A, an Aspidosperma alkaloid, originally isolated from Tabernaemontana corymbosa, has proved to possess interesting anticancer activities. However, jerantinine A also induces toxicity to non-cancerous cells.

PURPOSE

We adopted a combinatorial approach with the joint application of γ-tocotrienol and jerantinine A at lower concentrations in order to minimize toxicity towards non-cancerous cells while improving the potency on brain cancer cells.

METHODS

The antiproliferative potency of individual γ-tocotrienol and jerantinine A as well as combined in low-concentration was firstly evaluated on U87MG cancer and MRC5 normal cells. Morphological changes, DNA damage patterns, cell cycle arrests and the effects of individual and combined low-concentration compounds on microtubules were then investigated. Finally, the potential roles of caspase enzymes and apoptosis-related proteins in mediating the apoptotic mechanisms were investigated using apoptosis antibody array, ELISA and Western blotting analysis.

RESULTS

Combinatorial study between γ-tocotrienol at a concentration range (0-24µg/ml) and fixed IC₂₀ concentration of jerantinine A (0.16µg/ml) induced a potent antiproliferative effect on U87MG cells and led to a reduction on the new half maximal inhibitory concentration of γ-tocotrienol (i.e._tIC₅₀=1.29µg/ml) as compared to that of individual γ-tocotrienol (i.e. IC₅₀=3.17µg/ml). A reduction on undesirable toxicity to MRC5 normal cells was also observed. G0/G1 cell cycle arrest was evident on U87MG cells receiving IC₅₀ of individual γ-tocotrienol and combined low-concentration compounds (1.29µg/ml γ-tocotrienol + 0.16µg/ml jerantinine A), whereas, a profound G2/M arrest was evident on cells treated with IC₅₀ of individual jerantinine A. Additionally, individual jerantinine A and combined compounds (except individual γ-tocotrienol) caused a disruption of microtubule networks triggering Fas- and p53-induced apoptosis mediated via the death receptor and mitochondrial pathways.

CONCLUSIONS

These findings demonstrated that the combined use of lower concentrations of γ-tocotrienol and jerantinine A induced potent cytotoxic effects on U87MG cancer cells resulting in a reduction on the required individual concentrations and thereby minimizing toxicity of jerantinine A towards non-cancerous MRC5 cells as well as probably overcoming the high-dose limiting application of γ-tocotrienol. The multi-targeted mechanisms of action of the combination approach have shown a therapeutic potential against brain cancer in vitro and therefore, further in vivo investigations using a suitable animal model should be the way forward.

In vitro evaluation of osteoblast adhesion, proliferation and differentiation on chitosan-TiO2 nanotubes scaffolds with Ca2+ ions

Hydrothermally synthesized TiO₂ nanotubes (TNTs) were first used as a filler for chitosan scaffold for reinforcement purpose. Chitosan-TNTs (CTNTs) scaffolds prepared via direct blending and freeze drying retained cylindrical structure and showed enhanced compressive modulus and reduced degradation rate compared to chitosan membrane which experienced severe shrinkage after rehydration with ethanol. Macroporous interconnectivity with pore size of 70-230μm and porosity of 88% were found in CTNTs scaffolds. Subsequently, the functionalization of CTNTs scaffolds with CaCl₂ solutions (0.5mM-40.5mM) was conducted at physiological pH. The adsorption isotherm of Ca²⁺ ions onto CTNTs scaffolds fitted well with Freundlich isotherm. CTNTs scaffolds with Ca²⁺ ions showed high biocompatibility by promoting adhesion, proliferation and early differentiation of MG63 in a non-dose dependent manner. CTNTs scaffolds with Ca²⁺ ions can be an alternative for bone regeneration.

Purification and immunogenicity of hemagglutinin from highly pathogenic avian influenza virus H5N1 expressed in Nicotiana benthamiana

Highly pathogenic avian influenza (HPAI) H5N1 is an ongoing global health concern due to its severe sporadic outbreaks in Asia, Africa and Europe, which poses a potential pandemic threat. The development of safe and cost-effective vaccine candidates for HPAI is considered the best strategy for managing the disease and addressing the pandemic preparedness. The most potential vaccine candidate is the antigenic determinant of influenza A virus, hemagglutinin (HA). The present research was aimed at developing optimized expression in Nicotiana benthamiana and protein purification process for HA from the Malaysian isolate of H5N1 as a vaccine antigen for HPAI H5N1. Expression of HA from the Malaysian isolate of HPAI in N. benthamiana was confirmed, and more soluble protein was expressed as truncated HA, the HA1 domain over the entire ectodomain of HA. Two different purification processes were evaluated for efficiency in terms of purity and yield. Due to the reduced yield, protein degradation and length of the 3-column purification process, the 2-column method was chosen for target purification. Purified HA1 was found immunogenic in mice inducing H5 HA-specific IgG and a hemagglutination inhibition antibody. This paper offers an alternative production system of a vaccine candidate against a locally circulating HPAI, which has a regional significance.

Cloud-point extraction of green-polymers from Cupriavidus necator lysate using thermoseparating-based aqueous two-phase extraction

Polyhydroxyalkanoates (PHAs), a class of renewable and biodegradable green polymers, have gained attraction as a potential substitute for the conventional plastics due to the increasing concern towards environmental pollution as well as the rapidly depleting petroleum reserve. Nevertheless, the high cost of downstream processing of PHA has been a bottleneck for the wide adoption of PHAs. Among the options of PHAs recovery techniques, aqueous two-phase extraction (ATPE) outshines the others by having the advantages of providing a mild environment for bioseparation, being green and non-toxic, the capability to handle a large operating volume and easily scaled-up. Utilizing unique properties of thermo-responsive polymer which has decreasing solubility in its aqueous solution as the temperature rises, cloud point extraction (CPE) is an ATPE technique that allows its phase-forming component to be recycled and reused. A thorough literature review has shown that this is the first time isolation and recovery of PHAs from Cupriavidus necator H16 via CPE was reported. The optimum condition for PHAs extraction (recovery yield of 94.8% and purification factor of 1.42 fold) was achieved under the conditions of 20 wt/wt % ethylene oxide-propylene oxide (EOPO) with molecular weight of 3900 g/mol and 10 mM of sodium chloride addition at thermoseparating temperature of 60°C with crude feedstock limit of 37.5 wt/wt %. Recycling and reutilization of EOPO 3900 can be done at least twice with satisfying yield and PF. CPE has been demonstrated as an effective technique for the extraction of PHAs from microbial crude culture.

Exceedingly Higher co-loading of Curcumin and Paclitaxel onto Polymer-functionalized Reduced Graphene Oxide for Highly Potent Synergistic Anticancer Treatment

Metastasis of lung carcinoma to breast and vice versa accounts for one of the vast majority of cancer deaths. Synergistic treatments are proven to be the effective method to inhibit malignant cell proliferation. It is highly advantageous to use the minimum amount of a potent toxic drug, such as paclitaxel (Ptx) in ng/ml together with a natural and safe anticancer drug, curcumin (Cur) to reduce the systemic toxicity. However, both Cur and Ptx suffer from poor bioavailability. Herein, a drug delivery cargo was engineered by functionalizing reduced graphene oxide (G) with an amphiphilic polymer, PF-127 (P) by hydrophobic assembly. The drugs were loaded via pi-pi interactions, resulting in a nano-sized GP-Cur-Ptx of 140 nm. A remarkably high Cur loading of 678 wt.% was achieved, the highest thus far compared to any other Cur nanoformulations. Based on cell proliferation assay, GP-Cur-Ptx is a synergistic treatment (CI < 1) and is highly potent towards lung, A549 (IC50 = 13.24 μg/ml) and breast, MDA-MB-231 (IC50 = 1.450 μg/ml) cancer cells. These positive findings are further confirmed by increased reactive oxygen species, mitochondrial membrane potential depletion and cell apoptosis. The same dose treated on normal MRC-5 cells shows that the system is biocompatible and cancerous cell-specific.

Synergistic cytotoxic effects of combined δ-tocotrienol and jerantinine B on human brain and colon cancers

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Tabernaemontana has widespread distribution throughout tropical and subtropical parts of the world, i.e. Africa, Asia and America which has long been used for treatments of different disease conditions including tumours, wounds, syphilis, stomach ache and headache. Some Tabernaemontana species are used for treatment of piles, spleen and abdominal tumours in India. In particular, the leaf of Tabernaemontana corymbosa is used for treatment of tumours in Bangladesh. Parts of the plant or whole plants are used as decoctions, steam bath, powder and ointments.

AIM OF STUDY

The present study was undertaken to study the mechanism of apoptosis induction in human glioblastoma (U87MG) and colorectal adenocarcinoma (HT-29) cancer cells by a novel indole alkaloid, jerantinine B isolated from T. corymbosa, δ-tocotrienol and the combined low-dose treatments of δ-tocotrienol with IC20 dose of jerantinine B.

MATERIALS AND METHODS

Cell viability, isobologram and combinational index (CI) analyses were used to determine the pharmacological interaction between combined treatments based on the IC50 values obtained. Fluorescence and histochemical staining techniques as well as comet assay were used for evaluating the morphological changes and DNA damage pattern, respectively. The effects of treatments on microtubules, caspase activity and cell death were determined using immunofluorescence technique, caspase colorimetric and neutral red uptake assays, respectively.

RESULTS

Jerantinine B, δ-tocotrienol and combined low-dose treatments induced a dose-dependent growth inhibition against U87MG and HT-29 cells selectively with less toxicity acted towards the normal MRC5 cells. Synergistic growth inhibition observed with CI values of 0.85 and 0.77 for U87MG and HT-29 cells, resulting in up to 2-fold and 3.8-fold dose reduction of δ-tocotrienol and jerantinine B, respectively. U87MG and HT-29 cells exhibited morphological features of apoptosis and double stranded DNA breaks. Individual and combined treatments induced caspase 8 and 3 activities and cell death independent of caspase activation on U87MG and HT-29 cells. An increased caspase 9 activity was also evident on U87MG and HT-29 treated with combined treatments and HT-29 cells treated with jerantinine B. Jerantinine B and combined low-dose treatments with δ-tocotrienol undoubtedly disrupted the microtubule networks.

CONCLUSION

The present study demonstrated the mechanism for cytotoxic potency of δ-tocotrienol and jerantinine B against U87MG and HT-29 cells. Furthermore, combined low-dose treatments induced concurrent synergistic inhibition of cancer cell growth with concomitant dose reduction thus minimizing toxicity to normal cells and improving potency of δ-tocotrienol and jerantinine B.

Conjugation of insulin onto the sidewalls of single-walled carbon nanotubes through functionalization and diimide-activated amidation

PURPOSE

The high aspect ratio of carbon nanotubes (CNTs) allows the attachment of compounds that enhance the functionality of the drug vehicle. Considering this, use of CNTs as a multifunctional insulin carrier may be an interesting prospect to explore.

MATERIALS AND METHODS

The carboxylic acid groups were functionalized on the sidewalls of single-walled CNTs (SWCNTs) followed by diimidation to form amide bonds with the amine groups of the insulin.

RESULTS

Scanning transmission electron microscopy and transmission electron microscopy establish clear conjugation of insulin onto the surface of nanotube sidewalls. The incorporation of insulin further increased the solubility of SWCNTs in biological solution for the tested period of 5 months. Bicinchoninic acid assay confirms that 0.42 mg of insulin could be attached to every 1 mg of carboxylated SWCNTs.

CONCLUSION

With the successful conjugation of insulin to SWCNTs, it opens up the potential use of SWCNTs as an insulin carrier which in need of further biological studies.

Current perspectives on dengue episode in Malaysia

Prevalence of dengue transmission has been alarmed by an estimate of 390 million infections per annum. Urban encroachment, ecological disruption and poor sanitation are all contributory factors of increased epidemiology. Complication however arises from the fact that dengue virus inherently exists as four different serotypes. Secondary infection is often manifested in the more severe form, such that antibody-dependent enhancement (ADE) could aggravate ailment by allowing pre-existing antibodies to form complexes with infecting viruses as means of intrusion. Consequently, increased viraemic titter and suppression of antiviral response are observed. Deep concerns are thus expressed in regards to escalating trend of hospitalisation and mortality rates. In Malaysia, situation is exacerbated by improper clinical management and pending vector control operations. As a preparedness strategy against the potential deadly dengue pandemic, the call for development of a durable and cost-effective dengue vaccine against all infecting serotypes is intensified. Even though several vaccine candidates are currently being evaluated in clinical trials, uncertainties in regards to serotypes interference, incomplete protection and dose adequacy have been raised. Instead of sole reliance on outsourcing, production of local vaccine should be considered in coherent to government's efforts to combat against dengue.

A Proof of Concept: Detection of Avian Influenza H5 Gene by a Graphene-Enhanced Electrochemical Genosensor

The highly pathogenic avian influenza (HPAI) virus subtype H5N1 has been found to be the most virulent and deadliest virus strain, with capability of interspecies transmission to human infection. Most human HPAI H5N1 cases were diagnosed late in their illnesses for medical care, resulting in severe complications that led to death. In this study, a novel graphene-enhanced electrochemical DNA biosensor had been fabricated for the detection of polymerase chain reaction (PCR) amplicon derived from the haemagglutinin (H5) gene of the HPAI. The graphene-enhanced DNA biosensor showed excellent linear correlation between PCR amplicon concentration and amperometric signal with a correlation coefficient, r2 of 0.9987. The amperometric response of the proposed biosensor was compared with conventional gel electrophoresis while the feasibility of the proposed sandwich sensing platform was verified via dot blot assay. The results obtained indicate that the electrochemical DNA biosensing assay is significantly more sensitive (P < 0.05) and time efficient. This work serves as a proof of concept in hopes for further development of the graphene enhanced electrochemical DNA biosensor into a portable, on-site screening platform for point-of-care detection of various pathogens.

A review on ethnobotany, pharmacology and phytochemistry of Tabernaemontana corymbosa

OBJECTIVES

Tabernaemontana is a genus from the plant family, Apocynaceae with vast medicinal application and widespread distribution in the tropics and subtropics of Africa, Americas and Asia. The objective of this study is to critically evaluate the ethnobotany, medicinal uses, pharmacology and phytochemistry of the species, Tabernaemontana corymbosa (Roxb. ex Wall.) and provide information on the potential future application of alkaloids isolated from different parts of the plant.

KEY FINDINGS

T. corymbosa (Roxb. ex Wall.) parts are used as poultice, boiled juice, decoctions and infusions for treatment against ulceration, fracture, post-natal recovery, syphilis, fever, tumours and orchitis in Malaysia, China, Thailand and Bangladesh. Studies recorded alkaloids as the predominant phytochemicals in addition to phenols, saponins and sterols with vast bioactivities such as antimicrobial, analgesic, anthelmintic, vasorelaxation, antiviral and cytotoxicity.

SUMMARY

An evaluation of scientific data and traditional medicine revealed the medicinal uses of different parts of T. corymbosa (Roxb. ex Wall.) across Asia. Future studies exploring the structure-bioactivity relationship of alkaloids such as jerantinine and vincamajicine among others could potentially improve the future application towards reversing anticancer drug resistance.

Thermoseparating aqueous two-phase systems: Recent trends and mechanisms

Having the benefits of being environmentally friendly, providing a mild environment for bioseparation, and scalability, aqueous two-phase systems (ATPSs) have increasingly caught the attention of industry and researchers for their application in the isolation and recovery of bioproducts. The limitations of conventional ATPSs give rise to the development of temperature-induced ATPSs that have distinctive thermoseparating properties and easy recyclability. This review starts with a brief introduction to thermoseparating ATPSs, including its history, unique characteristics and advantages, and lastly, key factors that influence partitioning. The underlying mechanism of temperature-induced ATPSs is covered together with a summary of recent applications. Thermoseparating ATPSs have been proven as a solution to the demand for economically favorable and environmentally friendly industrial-scale bioextraction and purification techniques.

Inhibition of penicillin-binding protein 2a (PBP2a) in methicillin resistant Staphylococcus aureus (MRSA) by combination of ampicillin and a bioactive fraction from Duabanga grandiflora

Background

The inhibition of penicillin-binding protein 2a (PBP2a) is a promising solution in overcoming resistance of methicillin resistance Staphylococcus aureus (MRSA). A potential approach in achieving this is by combining natural product with currently available antibiotics to restore the activity as well as to amplify the therapeutic ability of the drugs. We studied inhibition effects of a bioactive fraction, F-10 (isolated from the leaves of Duabanga grandiflora) alone and in combination with a beta-lactam drug, ampicillin on MRSA growth and expression of PBP2a. Additionally, phytochemical analysis was conducted on F-10 to identify the classes of phytochemicals present.

Methods

Fractionation of the ethyl acetate leaf extract was achieved by successive column chromatography which eventually led to isolation of an active fraction, F-10. Both extract and F-10 were analyzed for the presence of major classes of phytochemicals in addition to obtaining a high performance liquid chromatography (HPLC) profile to reveal the complexity of the fraction F-10. Broth microdilution method was employed to determine minimum inhibitory concentration (MIC) of the extract and fractions against MRSA. Evaluation of synergistic activity of the active fraction with ampicillin was determined using checkerboard methodand kinetic growth experiments. Effect of combination treatments on expression of PBP2a, a protein that confers resistance to beta-lactam antibiotics, was elucidated with the Western blot assay.

Results

MIC of F-10 against MRSA was 750 mg/L which showed an improved activity by 4-fold compared to its crude extract (MIC = 3000 mg/L). Phytochemical analysis revealed occurrence of tannins, saponin, flavonoids, sterols, and glycosides in F10 fraction. In FIC index interpretation, the most synergistic activity was achieved for combinations of 1/64 × MIC ampicillin + 1/4 × MIC F-10. The combination also evidently inhibited MRSA growth in kinetic growth curve assay. As a result of this synergistic interaction, MIC of ampicillin against MRSA was reduced to 0.78 mg/L (64-fold) from initial value of 50 mg/L. Western blot analysis suggested inhibition of PBP2a in MRSA cultures grown in synergistic combination treatment in which no PBP2a band was expressed.

Conclusions

The results demonstrated synergism between fraction F-10 of D. grandiflora with ampicillin in suppressing MRSA growth via PBP2a inhibition.

Reduction of MTT to Purple Formazan by Vitamin E Isomers in the Absence of Cells

The yellow tetrazolium salt 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) is widely used to determine cell viability in cell proliferation and cytotoxic assays. MTT is reduced by metabolically active cells to form an insoluble purple formazan product that is quantifiable by spectrophotometry. It is the most common and direct assay for cell viability. However, in this present study, we demonstrated that the vitamin E isomers α-β-γ-δ-tocotrienols and α-tocopherol were able to reduce MTT into a formazan product, despite the absence of living cells. For comparison, a second method for determining cell viability, which is the neutral red uptake assay, was used in parallel with the MTT assay. The results showed that neutral red did not interact with the vitamin E isomers. Our findings suggest that the MTT assay is not suitable for studying the proliferative effects of vitamin E isomers on cell growth.

Prevention of cell-surface attachment and reduction of penicillin-binding protein 2a (PBP2a) level in methicillin-resistant Staphylococcus aureus biofilms by Acalypha wilkesiana

BACKGROUND

Formation of biofilm is known to enhance the virulence of methicillin-resistance Staphylococcus aureus (MRSA), which is associated with persistent infections in hospital settings. The biofilm layer essentially forms a protective barrier encapsulating the bacterial colony and thus reduces the effectiveness of chemotherapeutics. We have isolated 9EA-FC-B bioactive fraction from Acalypha wilkesiana Müll. Arg. that reverses ampicillin resistant in MRSA through inhibition of the antibiotic resistant protein, penicillin-binding protein 2a (PBP2a). In this study, we aimed to investigate the effects of 9EA-FC-B on MRSA biofilm forming capacity.

METHODS

Inhibition of biofilm production and microtiter attachment assays were employed to study the anti-biofilm activity of 9EA-FC-B, while latex agglutination test was performed to investigate the effect on PBP2a in the biofilm matrix. We also attempted to characterise the chemical components of the fraction using high performance liquid chromatography (HPLC) and phytochemical analysis.

RESULTS

Fraction 9EA-FC-B and ampicillin exhibited similar inhibitory effect on MRSA's biofilm production at their respective minimum inhibitory concentrations (81.56% vs 84.49%, respectively). However, the test fraction was more effective in suppressing cell surface attachment (90.85%) compared to ampicillin (37.8%). Interestingly, ampicillin enhanced the level PBP2a and in the contrary 9EA-FC-B attenuated the production of the resistant protein in the bioflim matrix. HPLC and phytochemical analysis revealed that 9EA-FC-B fraction is a complex mixture containing tannins, saponins, sterol/steroids, and glycosides.

CONCLUSIONS

Bioactive fraction 9EA-FC-B inhibited the production of MRSA biofilm by preventing the initial cell-surface attachment and reducing the amount PBP2a in the matrix. PBP2a found in the biofilm matrix is believed to have a role in the development of virulence in MRSA.

Exceedingly biocompatible and thin-layered reduced graphene oxide nanosheets using an eco-friendly mushroom extract strategy

PURPOSE

A simple, one-pot strategy was used to synthesize reduced graphene oxide (RGO) nanosheets by utilizing an easily available over-the-counter medicinal and edible mushroom, Ganoderma lucidum.

METHODS

The mushroom was boiled in hot water to liberate the polysaccharides, the extract of which was then used directly for the reduction of graphene oxide. The abundance of polysaccharides present in the mushroom serves as a good reducing agent. The proposed strategy evades the use of harmful and expensive chemicals and avoids the typical tedious reaction methods.

RESULTS

More importantly, the mushroom extract can be easily separated from the product without generating any residual byproducts and can be reused at least three times with good conversion efficiency (75%). It was readily dispersible in water without the need of ultrasonication or any surfactants; whereas 5 minutes of ultrasonication with various solvents produced RGO which was stable for the tested period of 1 year. Based on electrochemical measurements, the followed method did not jeopardize RGO's electrical conductivity. Moreover, the obtained RGO was highly biocompatible to not only colon (HT-29) and brain (U87MG) cancer cells, but was also viable towards normal cells (MRC-5).

CONCLUSION

Besides being eco-friendly, this mushroom based approach is easily scalable and demonstrates remarkable RGO stability and biocompatibility, even without any form of functionalization.

Anhedonia among patients with Major Depressive Disorder: A comparison between patients on escitalopram and healthy controls

BACKGROUND AND AIMS

Escitalopram has widely been recognized as one of the most frequently used antidepressants, with superior tolerability and great efficacy in preventing major depressive disorder (MDD) relapse and recurrence. However, anhedonia, which is a core symptom of MDD, remains difficult to treat. This study investigates the hedonic levels of MDD patients treated with Escitalopram.

MATERIALS AND METHODS

A total of 108 participants, 26 of whom with MDD on Escitalopram, were recruited in this cross sectional study. They were evaluated using the Snaith-Hamilton Pleasure Scale (SHAPS) and Beck Depression Inventory (BDI) questionnaires to assess their hedonic state, general mental health condition and level of depression.

RESULTS

Our study shows that most items in the SHAPS scores are significantly different between MDD patients on Escitalopram and the controls.

CONCLUSIONS

The hedonic capacity remains different between the two groups despite patients with MDD are put on Escitalopram treatment. Escitalopram fails to alleviate the hedonic state of MDD patients. Antidepressants that improve both depressive symptoms and hedonic states should be considered when treating MDD patients in clinical settings.

Alkaloid extracts of Ficus species and palm oil-derived tocotrienols synergistically inhibit proliferation of human cancer cells

Tocotrienols have been reported to possess anticancer effects other than anti-inflammatory and antioxidant activities. This study explored the potential synergism of antiproliferative effects induced by individual alkaloid extracts of Ficus fistulosa, Ficus hispida and Ficus schwarzii combined with δ- and γ-tocotrienols against human brain glioblastoma (U87MG), lung adenocarcinoma (A549) and colorectal adenocarcinoma (HT-29) cells. Cell viability and morphological results demonstrated that extracts containing a mixture of alkaloids from the leaves and bark of F. schwarzii inhibited the proliferation of HT-29 cells, whereas the alkaloid extracts of F. fistulosa inhibited the proliferation of both U87MG and HT-29 cells and showed synergism in combined treatments with either δ- or γ-tocotrienol resulting in 2.2-34.7 fold of reduction in IC50 values of tocotrienols. The observed apoptotic cell characteristics in conjunction with the synergistic antiproliferative effects of Ficus species-derived alkaloids and tocotrienols assuredly warrant future investigations towards the development of a value-added chemotherapeutic regimen against cancers.

Antiproliferation and induction of caspase-8-dependent mitochondria-mediated apoptosis by β-tocotrienol in human lung and brain cancer cell lines

The pure vitamin isomer, β-tocotrienol has the least abundance among the other vitamin E isomers that are present in numerous plants. Hence, it is very scarcely studied for its bioactivity. In this study, the antiproliferative effects and primary apoptotic mechanisms of β-tocotrienol on human lung adenocarcinoma A549 and glioblastoma U87MG cells were investigated. It was evidenced that β-tocotrienol had inhibited the growth of both A549 (GI50=1.38±0.334μM) and U87MG (GI50=2.53±0.604μM) cells at rather low concentrations. Cancer cells incubated with β-tocotrienol were also found to exhibit hallmarks of apoptotic morphologies including membrane blebbing, chromatin condensation and formation of apoptotic bodies. The apoptotic properties of β-tocotrienol in both A549 and U87MG cells were the results of its capability to induce significant (P<0.05) double-strand DNA breaks (DSBs) without involving single-strand DNA breaks (SSBs). β-Tocotrienol is said to induce activation of caspase-8 in both A549 and U87MG cells guided by no activation when caspase-8 inhibitor, z-IETD-fmk was added. Besides, disruption on the mitochondrial membrane permeability of the cells in a concentration- and time-dependent manner had occurred. The induction of apoptosis by β-tocotrienol in A549 and U87MG cells was confirmed to involve both the death-receptor mediated and mitochondria-dependent apoptotic pathways. These findings could potentiate the palm oil derived β-tocotrienol to serve as a new anticancer agent for treating human lung and brain cancers.

Protein profiling and histone deacetylation activities in somaclonal variants of oil palm (Elaeis guineensis Jacq.)

Mantled fruits as a result of somaclonal variation are often observed from the oil palm plantlets regenerated via tissue culture. The mantling of fruits with finger-like and thick outer coating phenotypes significantly reduces the seed size and oil content, posing a threat to oil palm planters, and may jeopardize the economic growth of countries that depend particularly on oil palm plantation. The molecular aspects of the occurrence of somaclonal variations are yet to be known, possibly due to gene repression such as DNA methylation, histone methylation and histone deacetylation. Histone deacetylases (HDACs), involved in eukaryotic gene regulation by catalyzing the acetyl groups are removal from lysine residues on histone, hence transcriptionally repress gene expression. This paper described the total protein polymorphism profiles of somaclonal variants of oil palm and the effects of histone deacetylation on this phenomenon. Parallel to the different phenotypes, the protein polymorphism profiles of the mantled samples (leaves, fruits, and florets) and the phenotypically normal samples were proven to be different. Higher HDAC activity was found in mantled leaf samples than in the phenotypically normal leaf samples, leading to a preliminary conclusion that histone deacetylation suppressed gene expression and contributed to the development of somaclonal variants.

Cross-reactivity of Malaysian rat cytomegalovirus strains with its human counterpart

This study probes into the prospect of cross-reactivity of HCMV with RCMV which has not been acknowledged to date. We describe the uncovering of a protein with an estimated size of between 61-68 kDa from local RCMV strains which reacted with HCMV positive sera. Our findings are a first disclosure of a plausible immunological cross-reactivity between RCMV with its human counterpart which grounds substantial interest implying existence of conserved determinants between rat and human CMV polypeptides. The cross-reactive protein most likely represents an enveloped glycoprotein, though the precise identification and its degree of similarity needs to be evidently defined and further elucidated in forthcoming experiments.

Acalypha wilkesiana extracts induce apoptosis by causing single strand and double strand DNA breaks

ETHNOPHARMACOLOGICAL RELEVANCE

The seeds of Acalypha wilkesiana have been used empirically by traditional healers in Southwest Nigeria together with other plants as a powder mixture to treat patients with breast tumours and inflammation.

AIM OF THE STUDY

There is an increasing interest among researchers in searching for new anticancer drugs from natural resources, particularly plants. This study aimed to investigate the anticancer properties of Acalypha wilkesiana extracts and the characteristics of DNA damage against brain and lung cancer cells.

MATERIALS AND METHODS

The antiproliferative activity of Acalypha wilkesiana extracts (ethyl acetate, hexane, and ethanol) was examined on human glioma (U87MG), human lung carcinoma (A549), and human lung fibroblast (MRC5) cells.

RESULTS

Cell viability MTT assay revealed that ethyl acetate extract of the plant possessed significant antiproliferative effects against both U87MG (GI(50)=28.03 ± 6.44 μg/ml) and A549 (GI(50)=89.63 ± 2.12 μg/ml) cells (p value<0.0001). The hexane extract was found to exhibit crucial antiproliferative effects on U87MG (GI(50)=166.30 ± 30.50 μg/ml) (p value<0.0001) but not on A549 cells. Neither plant extract possessed noticeable antiproliferative effects on the non-cancerous MRC5 cells (GI(50)>300 μg/ml). The ethanol extract showed no antiproliferative effects on any cell line examined. Haematoxylin & Eosin (H & E) staining and single cell gel electrophoresis (SCGE) comet assay confirmed that plant extract-treated cells underwent apoptosis and not necrosis. SCGE comet assays confirmed that plant extracts caused both single strand (SSB) and double strand (DSB) DNA breaks that led to the execution of apoptosis.

CONCLUSION

The extracts (especially ethyl acetate and hexane) of Acalypha wilkesiana possess valuable cytotoxic effects that trigger apoptosis in U87MG and A549 cancer cells through induction of DNA SSBs and DSBs.

Development of a quantitative real-time RT-PCR for kinetic analysis of immediate-early transcripts of rat cytomegalovirus

One-step real-time RT-PCR assay was developed for quantification of the immediate-early (IE), namely IE1 and IE2 transcripts of Rat cytomegalovirus (RCMV), strain ALL-03 in rat embryonic fibroblast cells (REF). This in-house SYBR Green I based RT-PCR was shown to have higher amplification efficiency and detection limit as compared to a commercially available real-time RT-PCR kit in quantifying these two transcripts. The quantification histogram revealed the divergence of transcription activities of the two IE genes. The IE1 transcript had a concentration peak at 7 hrs post infection (p.i.), whereas IE2 transcript at 20 hrs p.i. Regulation of IE expression is critical for determination, whether the infection is going to be abortive, lytic or latent. Therefore, this in-house developed quantitative RT-PCR assay offers an alternative for diagnosis and monitoring of the acute cytomegalovirus (CMV) infection directed at IE transcript detection.

Pathogenesis and antibody response to a cytomegalovirus infection in newborn rats

The present study described the kinetics of Rat cytomegalovirus (RCMV) infection in newborn rats by monitoring infectious virus and viral antigens in various organs, viral DNA in the blood (DNAemia) and antibody response. These parameters were evaluated quantitatively using double-antibody sandwich ELISA (DAS-ELISA), real-time PCR, indirect ELISA and virus infectivity assay. For the first time DAS-ELISA was used for detection of RCMV antigen directly from organ samples. The relationships between the presence of viral antigens in the infected organs and antibody levels were established by the Spearman's rank test. It was found that the virus was present in the blood, spleen, liver, lungs, and kidneys earlier than in the salivary glands. Furthermore, the early immunity of the newborn rats led to a delayed seroconversion. We suggested that the prolonged presence of the virus in salivary glands could augment the antibody response that conversely might be responsible for a reduction of viremia. This study expanded our understanding of RCMV pathogenesis leading to improved therapeutic and preventive treatment regimens particularly for the neonatal Human cytomegalovirus (HCMV) infections. Additionally, the detection procedures developed in this study such as DAS-ELISA and real-time PCR could serve as alternative techniques for rapid screening of large number of samples.

Pathogenesis and vertical transmission of a transplacental rat cytomegalovirus

BACKGROUND

Cytomegalovirus (CMV) congenital infection is the major viral cause of well-documented birth defects in human. Because CMV is species-specific, the main obstacle to developing animal models for congenital infection is the difference in placental architecture, which preludes virus transmission across the placenta. The rat placenta, resembling histologically to that of human, could therefore facilitate the study of CMV congenital infection in human.

RESULTS

In this report, we present clear evidences of the transplacental property of a new rat CMV (RCMV), namely ALL-03, which had been isolated from placenta and uterus of the house rat. Our study signifies the detection of infectious virus, virus particles, viral protein and DNA as well as immune response to demonstrate a natural model of acute CMV infection including the immunocompetent and immunocompromised host associated with or without pregnancy. It is characterized by a full range of CMV related clinical signs; lesions and anatomical virus distribution to uterus, placenta, embryo, fetus, neonate, lung, kidney, spleen, liver and salivary gland of the infected rats in addition to the virus-specific seroconversion. The preference of the virus for different organs mimics the situation in immunocompromised man. Most interestingly, the placenta was observed to be involved in the maternofetal infection and hence confirmed the hypothesis that the RCMV strain ALL-03 is capable to cross the placenta and infect the offsprings congenitally.

CONCLUSION

The maternal viremia leading to uterine infection which subsequently infecting to the fetus through the placenta is the most likely phenomenon of CMV vertical transmission in our study.

Characterization of a novel rat cytomegalovirus (RCMV) infecting placenta-uterus of Rattus rattus diardii

A new rat cytomegalovirus (RCMV) isolated from the placenta/uterus of a house rat (Rattus rattus diardii) was found to productively infect rat embryo fibroblast (REF) cells. The virus produced typical herpesvirus-like cytopathic effects characterized by a lytic infection. The well-known herpesvirus morphology was confirmed by electron microscopy. Its slow growth in cell culture indicated that the virus is belonging to subfamily Betaherpesvirinae. Electron microscopy techniques and immunohistochemistry confirmed the presence of herpesviral inclusion bodies and virus related particles in the cytoplasm and nucleus of infected cells. Hyperimmune serum against the Maastricht strain of RCMV revealed the virus identity in neutralization test, immunoperoxidase and immunofluorescence techniques. Despite typical characteristics of CMV, the viral genome is significantly different from that of Maastricht, English, UPM/Sg and UPM/Kn strains. The dissimilarities, which have not been reported before, had been confirmed by mean of restriction endonuclease analysis. The new RCMV strain, a virus that infects placenta and uterus of rats, has been named as ALL-03.

Case reports: the use of intermaxillary screws to achieve intermaxillary fixation in the treatment of mandibular fractures

INTRODUCTION

Treatment of mandibular fractures commonly involves the use of arch bars in temporary maxillo-mandibular fixation (also called intermaxillary fixation) to aid bone plating, for the postoperative application of light elastic traction to correct minor occlusal discrepancies and intermaxillary fixation for post reduction immobilisation. The purpose of this paper is to describe a quick and simple alternative for intermaxillary fixation.

CLINICAL PICTURE

Three cases of mandibular fractures are presented to demonstrate the use of intermaxillary screws instead of conventional arch-bar wiring.

TREATMENT

Two cases were treated with closed reduction methods while the other case was treated with open reduction.

OUTCOME

Subsequent fracture healing was not compromised using this technique.

CONCLUSIONS

With careful case selection, successful treatment outcome may be achieved using this time-saving and technically simple procedure. Some of the advantages and disadvantages of the intermaxillary screws are discussed.

Root morphology of the maxillary first premolar in Singaporeans

Extracted teeth were collected from clinical procedures performed in the Faculty of Dentistry, National University of Singapore. A selected sample of 957 maxillary first premolars were subjected to visual examination and digital radiography. There was a higher incidence of two-root form (50.6 per cent) than previously reported for the Singaporean dentition. In the two-root category, 307 teeth exhibited the fused-root form (two fused roots with two root canals) and 177 were distinctively of the two-root form (two separate roots with two root canals and two foramina). The fused-root form was emphasized as an entity in this study. The one-root form accounted for 49.4 per cent. No three-root form was detected.

Trigeminal neuralgia. A retrospective survey of a sample of patients in Singapore and Malaysia

This survey was undertaken to study the clinical features of trigeminal neuralgia in an Asian population. Demographic data of 44 patients treated at the Dental Faculty of the National University of Singapore and at the University of Malaya were reviewed. The results of the survey were analysed and comparisons made with those of Caucasian patients as reported in other studies where there was a general similarity in the clinical findings. Trigeminal neuralgia presented predominantly in females. Right-sided involvement occurred at a greater frequency, and the peak age at onset was between the sixth and seventh decades of life. The only significant variant in the present sample was the greater involvement of the mandibular branch of the trigeminal nerve rather than the maxillary division. In addition, there was a much greater representation from Chinese patients over Malays as compared with their ratios in the general population.