Functional and structural analysis of non-synonymous single nucleotide polymorphisms (nsSNPs) in the MYB oncoproteins associated with human cancer

MYB proteins are highly conserved DNA-binding domains (DBD) and mutations in MYB oncoproteins have been reported to cause aberrant and augmented cancer progression. Identification of MYB molecular biomarkers predictive of cancer progression can be used for improving cancer management. To address this, a biomarker discovery pipeline was employed in investigating deleterious non-synonymous single nucleotide polymorphisms (nsSNPs) in predicting damaging and potential alterations on the properties of proteins. The nsSNP of the MYB family; MYB, MYBL1, and MYBL2 was extracted from the NCBI database. Five in silico tools (PROVEAN, SIFT, PolyPhen-2, SNPs&GO and PhD-SNP) were utilized to investigate the outcomes of nsSNPs. A total of 45 nsSNPs were predicted as high-risk and damaging, and were subjected to PMut and I-Mutant 2.0 for protein stability analysis. This resulted in 32 nsSNPs with decreased stability with a DDG score lower than - 0.5, indicating damaging effect. G111S, N183S, G122S, and S178C located within the helix-turn-helix (HTH) domain were predicted to be conserved, further posttranslational modifications and 3-D protein analysis indicated these nsSNPs to shift DNA-binding specificity of the protein thus altering the protein function. Findings from this study would help in the field of pharmacogenomic and cancer therapy towards better intervention and management of cancer.

Bioactive Compounds from Marine Sponges: Fundamentals and Applications

Marine sponges are sessile invertebrates that can be found in temperate, polar and tropical regions. They are known to be major contributors of bioactive compounds, which are discovered in and extracted from the marine environment. The compounds extracted from these sponges are known to exhibit various bioactivities, such as antimicrobial, antitumor and general cytotoxicity. For example, various compounds isolated from Theonella swinhoei have showcased various bioactivities, such as those that are antibacterial, antiviral and antifungal. In this review, we discuss bioactive compounds that have been identified from marine sponges that showcase the ability to act as antibacterial, antiviral, anti-malarial and antifungal agents against human pathogens and fish pathogens in the aquaculture industry. Moreover, the application of such compounds as antimicrobial agents in other veterinary commodities, such as poultry, cattle farming and domesticated cats, is discussed, along with a brief discussion regarding the mode of action of these compounds on the targeted sites in various pathogens. The bioactivity of the compounds discussed in this review is focused mainly on compounds that have been identified between 2000 and 2020 and includes the novel compounds discovered from 2018 to 2021.

Antimicrobial activity and mode of action of terpene linalyl anthranilate against carbapenemase-producing Klebsiella pneumoniae

Mining of plant-derived antimicrobials is the major focus at current to counter antibiotic resistance. This study was conducted to characterize the antimicrobial activity and mode of action of linalyl anthranilate (LNA) against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). LNA alone exhibited bactericidal activity at 2.5% (V/V), and in combination with meropenem (MPM) at 1.25% (V/V). Comparative proteomic analysis showed a significant reduction in the number of cytoplasmic and membrane proteins, indicating membrane damage in LNA-treated KPC-KP cells. Up-regulation of oxidative stress regulator proteins and down-regulation of oxidative stress-sensitive proteins indicated oxidative stress. Zeta potential measurement and outer membrane permeability assay revealed that LNA increases both bacterial surface charge and membrane permeability. Ethidium bromide influx/efflux assay showed increased uptake of ethidium bromide in LNA-treated cells, inferring membrane damage. Furthermore, intracellular leakage of nucleic acid and proteins was detected upon LNA treatment. Scanning and transmission electron microscopies again revealed the breakage of bacterial membrane and loss of intracellular materials. LNA was found to induce oxidative stress by generating reactive oxygen species (ROS) that initiate lipid peroxidation and damage the bacterial membrane. In conclusion, LNA generates ROS, initiates lipid peroxidation, and damages the bacterial membrane, resulting in intracellular leakage and eventually killing the KPC-KP cells.

Additivity vs Synergism: Investigation of the Additive Interaction of Cinnamon Bark Oil and Meropenem in Combinatory Therapy

Combinatory therapies have been commonly applied in the clinical setting to tackle multi-drug resistant bacterial infections and these have frequently proven to be effective. Specifically, combinatory therapies resulting in synergistic interactions between antibiotics and adjuvant have been the main focus due to their effectiveness, sidelining the effects of additivity, which also lowers the minimal effective dosage of either antimicrobial agent. Thus, this study was undertaken to look at the effects of additivity between essential oils and antibiotic, via the use of cinnamon bark essential oil (CBO) and meropenem as a model for additivity. Comparisons between synergistic and additive interaction of CBO were performed in terms of the ability of CBO to disrupt bacterial membrane, via zeta potential measurement, outer membrane permeability assay and scanning electron microscopy. It has been found that the additivity interaction between CBO and meropenem showed similar membrane disruption ability when compared to those synergistic combinations which was previously reported. Hence, results based on our studies strongly suggest that additive interaction acts on a par with synergistic interaction. Therefore, further investigation in additive interaction between antibiotics and adjuvant should be performed for a more in depth understanding of the mechanism and the impacts of such interaction.

Aspidofractinine and Eburnane Alkaloids from a North Borneo Kopsia. Ring-Contracted, Additional Ring-Fused, and Paucidactine-Type Aspidofractinine Alkaloids from K. pauciflora

Eleven new indole alkaloids (1-11) comprising seven aspidofractinine and four eburnane alkaloids, were isolated from the stem-bark extract of Kopsia pauciflora occurring in Malaysian Borneo. The aspidofractinine alkaloids include a ring-contracted, an additional ring-fused, a paucidactine regioisomer, two paucidactine, and one kopsine alkaloid. The structures of several of these alkaloids were also confirmed by X-ray diffraction analyses. The bisindole alkaloids isolated, norpleiomutine and kopsoffinol, showed in vitro growth inhibitory activity against human PC-3, HCT-116, MCF-7, and A549 cells and moderate effects in reversing multidrug-resistance in vincristine-resistant human KB cells.

Grandilodines A-C, biologically active indole alkaloids from Kopsia grandifolia

Three new indole alkaloids (1-3), named grandilodines A-C, and five known ones were obtained from the Malayan Kopsia grandifolia. The structures were established using NMR and MS analyses and, in the case of 1 and 2, were confirmed by X-ray diffraction analyses. Alkaloids 1, 3, and lapidilectine B (8) were found to reverse multidrug resistance in vincristine-resistant KB cells.

Eosinophilia and fleeting pulmonary shadows in a middle aged man

We present an unusual case of a malignancy associated with severe eosinophilia and fleeting pulmonary shadows. Initially limited to the lung, the illness progressed to involve multiple organs with marked increase in eosinophilia.

Ethnic differences in anthropometry among adult Singaporean Chinese, Malays and Indians, and their effects on lung volumes

When standing height (StndHt) cannot be assessed, arm span (AS) or sitting height (SitHt) has been used as surrogate variables for prediction of StndHt in adult caucasians and blacks. We examined (1) the relationship between StndHt, AS and SitHt among adult Chinese, Malays and Indians; and (2) whether anthropometry could explain the ethnic differences in lung volumes (as StndHt-adjusted lung volumes are known to differ significantly: Chinese > Malays > Indians). We recruited 1250 consecutive outpatients aged 20-90 years. Prediction equations of StndHt (with AS, SitHt, weight, age as predictors) for each subgroup of race and sex were formulated with multiple linear regressions. Equations with both AS and SitHt as predictors had the best goodness of fit (SEE = 2.37-2.85 cm, adjusted R2 = 0.67-0.87), as compared to equations with either AS (SEE = 3.00-3.91 cm, adjusted R2 = 0.58-0.80) or SitHt alone (SEE = 3.48-4.00 cm, adjusted R2 = 0.45-0.76). GLM general factorial analyses found that age- and weight-adjusted SitHt-to-StndHt ratios differed significantly among Chinese (0.539), Malays (0.529) and Indians (0.518). This paralleled the ethnic differences in lung volumes. The equations with both AS and SitHt as predictors provide the most accurate estimate of StndHt. Ethnic differences in upper body segment length may explain in part the lung volume differences.

Review of management of type 2 diabetes mellitus

BACKGROUND

Commonly used drugs for type 2 diabetes are not ideal. The sulphonylureas, especially potent and long-acting agents such as glibenclamide, can induce hypoglycaemia, while metformin carries the risk of lactic acidosis.

AIM

To review the management of type 2 diabetes at the major teaching hospital in Tasmania, Australia, principally to determine the extent of use of glibenclamide and metformin in the elderly and patients where published contraindications are present.

METHODS

A retrospective review of the medical records for 150 consecutive patients with type 2 diabetes admitted to the hospital in mid-1997, was performed. An extensive range of demographic and clinical variables was recorded for each patient. These included the duration of type 2 diabetes, the presence of other medical conditions, medication history, presence of any contraindications to the use of metformin or sulphonylureas, biochemical measures of diabetic control, and the presence of any diabetic complications.

RESULTS

The mean (+/-SD) age of the 150 patients included in the study was 70.1+/-11.8 years. The mean body mass index was 28.7+/-6.2 kg/m2 and the mean recent HbA1c level was 86+/-21%; only 24.7% of patients had a HbA1c level of 7% or lower. Of the 45 patients using glibenclamide, 40 (88.9%) had one or more risk factors for hypoglycaemia: over 65 years of age, renal impairment, or cognitive impairment and living alone. The study also found an extensive use of metformin in patients with contraindications and at highest risk of developing lactic acidosis. Sixty-six out of 70 patients (94%) using metformin had at least one contraindication according to the manufacturer's prescribing information, 57% of patients had two or three contraindications and 14% of patients had more than three contraindications. More than 20% of the patients had a renal function below published exclusion criteria.

CONCLUSIONS

There was evidence of over-utilization of metformin and glibenclamide in type 2 diabetes patients most at risk of adverse reactions. Insulin therapy could be a safer and more effective management strategy in many of these patients.