Risk Assessment, Interdependencies, and Source Appraisal of Bioaccumulated Heavy and Essential Metals in Seafood as Pollutants

Fish as seafood is a bioindicator for chemical substances like trace metals in the water systems that accumulate in fish bodies. Fe and Zn as essential and Pb, Ni, and Cd as heavy metals were quantitatively analyzed in fish muscle samples by an atomic absorption spectrophotometer (Perkin Elmer, Model AAnalyst-700). Fe and Zn's results agreed with the food quality guidelines. Fe was the highest in the range of 2.6-9.4 in mg kg-1. The Zn content indicates the contribution of anthropogenic agents through the food chain. Ni > Pb > Cd was found in marine fish species and Pb > Ni > Cd in freshwater fish. The results have been explored for source appraisal of bioaccumulated trace metals and categorized selected marine and freshwater species based on characteristics (like life cycle and habitats) by applying multivariate principal component analysis to risk assessment parameters. The Pearson correlation coefficients were applied to the risk assessment parameters for interdependencies of metals. Interestingly, synchronized outcomes were obtained with trace metal data. The study results were interpreted in the context of the fish type, habitat, surroundings, feed, life cycle, etc. The living habitats strongly affect trace metal accumulation, target hazard quotient (THQ), and target cancer risk (TR) attributes. The fishermen's community was at higher risk for carcinogenic effects than other seafood consumers. Overall, determinations for fish species were under safe limits as described by international regulatory bodies (FAO, WHO, ANHMRC, WAA).

In-vitro evaluation of virulence markers and antifungal resistance of clinical Candida albicans strains isolated from Karachi, Pakistan

Candidiasis is a significant fungal infection with high mortality and morbidity rates worldwide. Candida albicans is the most dominant species responsible for causing different manifestations of candidiasis. Certain virulence traits as well as its resistance to antifungal drugs contribute to the pathogenesis of this yeast. This study was designed to determine the production of some virulence factors, such as biofilm formation and extracellular hydrolytic enzymes (esterase, coagulase, gelatinase, and catalase) by this fungus, as well as its antifungal resistance profile. A total of 304 clinical C. albicans isolates obtained from different clinical specimens were identified by a conventional diagnostic protocol. The antifungal susceptibility of C. albicans strains was determined by disk diffusion technique against commercially available antifungal disks, such as nystatin 50 μg, amphotericin B 100 unit, fluconazole 25 μg, itraconazole 10 μg, ketoconazole 10 μg, and voriconazole 1 μg. The assessment of biofilm formation was determined by the tube staining assay and spectrophotometry. Gelatinase, coagulase, catalase, and esterase enzyme production was also detected using standard techniques. A total of 66.1% (201/304) and 28.9% (88/304) of C. albicans strains were susceptible-dose dependent (SDD) to nystatin and itraconazole, respectively. Among the antifungal drugs, C. albicans strains showed high resistance to ketoconazole 24.7% (75/304); however, no statistically significant relationship between the clinical origin of C. albicans isolates and antifungal drug resistance pattern was detected. For virulence factors, the majority of the C. albicans strains actively produced biofilm and all hydrolytic enzymes. Biofilm formation was demonstrated by 88% (267/304) of the strains with a quantitative mean value 0.1762 (SD ± 0.08293). However, 100% (304/304) of isolates produced catalase enzyme, 69% (211/304) produced coagulase, 66% (197/304) produced gelatinase, and 52% (157/304) produced esterase enzyme. A significant relationship between the source of specimens and biofilm formation by C. albicans was observed; nevertheless, there was no significant relationship between different sources of C. albicans strains and the production of different enzymatic virulence factors. The study found that C. albicans strains have excellent potential to produce virulence markers and resistance to antifungals, which necessitates surveillance of these opportunistic pathogens to minimize the chances of severe invasive infections.

Isolation of metallic salts of cytotoxic clerodanes from medicinal plant Polyalthia longifolia var. pendula

Isolation of sodium and potassium salt of kolavenic acid (1,2), as a mixture of (3:1) and sodium and potassium salt of 16 oxo-cleroda-3,13(14) E-dien-15-oic acid (3, 4) as a mixture of (1:1) are first time reported form reddish black ripe and green unripe berries of Polyalthia longifolia var. pendula respectively. Three known constituents obtained, were identified as cleroda-3, 13(14) E-dien-15-oic acid (kolavenic acid) (5), 16(R and S)-hydroxy cleroda-3,13 (14)Z-dien-15,16-olide (6) and 16 oxo-cleroda-3,13(14) E-dien-15-oic acid (7). Structures of all these compounds have been determined through spectral studies while metal analyses were carried out to confirm the structure of the salts. Compounds 3, 4 and 7 possess cytotoxic activity against lung (NCI-H460), oral (CAL-27) and normal mouse fibroblast (NCI-3T3) cancer cell lines. Diterpenoid (7), a bioprivileged, compound shows potent cytotoxic activity against oral cancer cell line (CAL-27) with IC₅₀ 11.3±0.6µg/mL in comparison with the standard 5-flourouracil (IC₅₀ 12.7±0.1µg/mL) and lungs cancer cell lines (NCI-H460) with IC₅₀ 5.3±0.2µg/mL as compared to the standard drug cisplatin (IC₅₀ 5.7±0.2µg/mL).

Estimations of potential risk of carcinogenic arsenic in smokeless tobacco products

Moderate arsenic exposure may lead to health problems, and thus, measuring arsenic (As) and inorganic arsenic (iAs) exposure from smokeless tobacco products (SLTs) for different population groups is important.

A Wide Bandgap Ag/MgO@Fe3O4 Nanocomposite as Magnetic Sorbent for Cd(II) in Water Samples

Background:

The magnetic nanocomposites are very important as a reusable sorbents for the extraction of Cd(II) and other toxic metals from water samples.

Methods:

The Ag/MgO@Fe3O4 nanocomposite was synthesized by the coprecipitation method and characterized by the XRD, EDX, SEM, UV-vis spectroscopy and FTIR. This nanocomposite was used to extract Cd(II) from water samples prior to its quantitative analysis with FAAS. Different variables, i.e. pH, temperature, amount of nanosorbent, adsorption/desorption and dilution were optimized.

Results:

The method was successfully applied to determine Cd(II) in real water samples with excellent recoveries (98%). The present method has lower detection (0.29) and quantification limit (0.97 ng mL-1).

Conclusions:

The Ag/MgO@Fe3O4 nanocomposite based magnetic extraction is a simple, fast, reproducible, less expansive and efficient technique for the Cd(II) extraction in water samples. The developed sorbent can be recycled and reused (20 times).

Trace metals health risk appraisal in fish species of Arabian Sea

Fish is a vital food for humans and many animals. We report an environmental monitoring study to assess the trace metals in fish species caught from Arabian Sea and commercially available in the coastal city Karachi, Pakistan. Heavy metals such as copper, iron, lead and cadmium were determined in the skin, fillet and heart of the fish species Pampus argenteus, Epinephelus chlorostigma, Rachycentron canadum, Scomberomorus commerson, Johnius belangerii, Labeo rohita, Lutjanus argentimaculatus, Trachinotus blochii, Pomadsys olivaceum and Acanthopagrus berda by the atomic absorption spectrophotometer. The concentration (mg kg⁻¹, dry weight) range was: Cd (0.00–0.041), Cu (0.006–0.189), Fe (0.413–4.952) and Pb (0.00–0.569). Cadmium, copper and iron levels were below the tolerable limits whereas concentration of lead in the skins of S. commerson, E. chlorostigma, J. belangerii, A. berda; L. argentimaculatus, fillets of J. belangerii, E. chlorostigma and in the heart of J. belangerii exceeded the recommended limits. Therefore fish skin should be discouraged as food for humans or animals. The results indicate that a number of fish species have higher concentration of heavy metals dangerous for human health. Since the fish P. olivaceum (Dhotar) has the lowest level of trace metals therefore we recommend it for breeding and human consumption.

Significance of isolation and drug susceptibility testing of non-Candida albicans species causing oropharyngeal candidiasis in HIV patients

Oropharyngeal candidiasis (OPC) continues to be a common opportunistic infection in patients infected with Human Immunodeficiency Virus (HIV) and is predictive of increasing immunosuppression. Though Candida albicans remains the predominant isolate, a rise in the frequency of isolation of non-albicans Candida (NAC) species is being observed. The levels of virulence and the sensitivities to available antifungal drugs vary among these species. Of 340 HIV seropositive patients in this study, 132 (38.8%) had oral lesions suggestive of candidiasis. Samples were collected from the lesion using sterile cotton swabs. Isolation and speciation were done by standard techniques. Antifungal drug susceptibility testing was done by macro broth dilution. The total number of Candida isolates was 135, of which, 45 (33.3%) were NAC species and 90 were C.albicans (66.6%). Of the NAC species, C. dubliniensis was the predominant pathogen (22,48.9%). Antifungal susceptibility testing showed that 14 (31.1%) of the NAC species and 11 (12.2%) of C. albicans were resistant to fluconazole (MIC > 8 microg/ml). A very high MIC of > 32 microg/ml was noted among the NAC species resistant to fluconazole.