Multidrug resistance of the pathogenic microorganisms to the antimicrobial drugs has become a major impediment toward successful diagnosis and management of infectious diseases. Recent advancements ...in nanotechnology-based medicines have opened new horizons for combating multidrug resistance in microorganisms. In particular, the use of silver nanoparticles (AgNPs) as a potent antibacterial agent has received much attention. The most critical physico-chemical parameters that affect the antimicrobial potential of AgNPs include size, shape, surface charge, concentration and colloidal state. AgNPs exhibits their antimicrobial potential through multifaceted mechanisms. AgNPs adhesion to microbial cells, penetration inside the cells, ROS and free radical generation, and modulation of microbial signal transduction pathways have been recognized as the most prominent modes of antimicrobial action. On the other side, AgNPs exposure to human cells induces cytotoxicity, genotoxicity, and inflammatory response in human cells in a cell-type dependent manner. This has raised concerns regarding use of AgNPs in therapeutics and drug delivery. We have summarized the emerging endeavors that address current challenges in relation to safe use of AgNPs in therapeutics and drug delivery platforms. Based on research done so far, we believe that AgNPs can be engineered so as to increase their efficacy, stability, specificity, biosafety and biocompatibility. In this regard, three perspectives research directions have been suggested that include (1) synthesizing AgNPs with controlled physico-chemical properties, (2) examining microbial development of resistance toward AgNPs, and (3) ascertaining the susceptibility of cytoxicity, genotoxicity, and inflammatory response to human cells upon AgNPs exposure.
Contamination of agricultural fields with Cadmium (Cd) due to several agricultural practices is increasing worldwide. The rice plants can easily take up Cd and accumulate it into different parts, ...including the grains, posing a threat to human health even at low concentration exposure. Several phytohormones, including Salicylic acid (SA) have been investigated since long for its alleviating properties under various biotic and abiotic stress conditions. In the present study, 100 μM SA application to ameliorate 25 μM Cd stress was studied for 72 h in hydroponics in Oryza sativa cv. Bandana seedlings. Pot experiments were done with same treatment condition and plants were grown till maturity. SA application to Cd exposed rice seedlings alleviated the stress condition, which was established by several physiological, biochemical, histochemical and gene expression analysis. SA treatment to Cd stressed seedlings showed elevated photosynthetic pigment content, on-protein thiol content and relieved the Cd induced growth inhibition considerably. It lowered the accumulation of ROS like, O2- and H2O2 with a regulated antioxidative enzymatic activity. SA application in Cd exposed rice seedlings had upregulated expression of OsHMA3 and OsPCS1 whereasOsNRAMP2 gene was downregulated. Co-application of SA and Cd led to higher yield and improved agronomic traits in comparison to only Cd exposed plants under pot experimentation. Daily intake of Cd and Carcinogenic risk were also reduced by 99.75% and 99.99% respectively in the SA treated Cd stressed plants. SA positively affected the growth and tolerance of rice seedlings to Cd stress. Hence, SA addition to Cd contaminated soil can ensure rice cultivation without posing health risk to consumers.
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•Hydroponically applied SA reduced the cadmium stress in Oryza sativa cv. Bandana.•SA application reduced cadmium accumulation in grain significantly.•Daily intake of metal and cadmium exposure associated cancer risk were decreased considerably.
Commuters’ exposure to size-segregated fine particulates in four public transport microenvironments was assessed in the Kolkata megacity of India. Personal exposure to PM
2.5
and PM
1
varied from ...130.8 & 112.1 μg m
−3
in air-conditioned (AC) buses, followed by 158.5 μg m
−3
& 134.3 μg m
−3
in non-AC buses, 187.1 μg m
−3
& 150.8 μg m
−3
in non-AC cars, to 242.2 μg m
−3
& 199.6 μg m
−3
in 3-wheeler auto rickshaws, respectively. The exposure ratio for PM
1
/PM
2.5
was comparable in all transport modes (0.64 to 0.94, 0.83 ± 0.07). The micromorphology of fine particulates, studied by scanning electron microscopy-energy-dispersive X-ray spectrometry, revealed several morphological features in both inorganic and carbonaceous particulates with Al, Si, Ca, K, Fe, and S impregnations. Soot particles were predominantly present in PM
< 0.25
, and its semi-aggregated net-like structure trapped fine and ultrafine particles. The possible formation of carbonaceous aerosols from inorganic seeds via the nucleation pathway was also captured. The estimated deposition rate in the human respiratory system translated into a total PM
2.5
respiratory deposition rate (RDR) of 25.5 ± 8.9 μg h
−1
in the respiratory tract was about 26% of the entire inhalation exposure to PM
2.5
. The average RDR of PM
2.5–1.0
and PM
1.0–0.5
was 11.7 ± 5.9 μg h
−1
and 4.5 ± 2.3 μg h
−1
that may get preferentially deposited in the head airways of the human respiratory system (75% and 60%, respectively). While the finest particles mainly get deposited in the deepest alveolar region of the human respiratory system (the RDR for PM
0.5–0.25
and PM
< 0.25
was 3.5 ± 1.5 μg h
−1
(49%) and 5.8 ± 2.5 μg h
−1
(79%), respectively). The highest airway deposition of PM
2.5
in auto rickshaw commuters indicates that this transport mode could be the most harmful to commuters exposing them to tailpipe emissions from on-road vehicles and resuspended road dust due to low floor height and the open nature of the vehicle. Auto rickshaw commuters should practice using PM
2.5
-restricting face masks to reduce exposure to fine particulates while commuting when this mode of commute cannot be avoided.
Cadmium (Cd) is a hazardous soil contaminant and causes environmental toxicity when present beyond the allowable limit in soil. It can alter growth and metabolism in both plants and animals even at ...very low concentration. Being sessile in nature, plants try to evade this harmful effect by adopting various defence mechanisms including activation of antioxidants and other metal homeostasis mechanisms. This study shows the varietal Cd stress tolerance capacity of rice cultivars commonly grown in West Bengal, which is a rice biodiversity region in India. Seven days old rice (Oryza sativa L.) seedlings were treated with 10 μM CdCl2 for another 7days and different physiological and biochemical stress parameters were studied to compare the varietal stress responses. Principle component analysis (PCA) and root tolerance index (RTI) revealed that rice cultivars I.E.T-4786, Jamini and Netiya, Maharaj showed divergent stress responses towards susceptibility and tolerance. Histochemical localization of hydrogen peroxide (H2O2), superoxide (O2˙-) and pot experiment were performed in these four cultivars (I.E.T-4786-Jamini and Netiya-Maharaj) to elucidate the different Cd stress tolerance. Histochemical analysis, agronomic traits and grain Cd content analyses showed that I.E.T-4786 and Jamini were susceptible with no Cd accumulation in grain, whereas cultivars Netiya and Maharaj were stress tolerant and Cd accumulators. In addition, health risk assessment was monitored for dietary intake of Cd through Cd accumulating rice and non Cd accumulating rice genotypes were identified. Thus, the study identified the Cd tolerant and sensitive cultivars grown locally.
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•TThe studied rice genotypes grown locally in West Bengal exhibit differential response towards Cd stress.•Cd toxicity negatively affects plant growth, maturation period and crop yield.•Rice cultivars that are able to tolerate Cd stress, are less affected as compared to the susceptible genotypes.•The studied tolerant cultivars accumulated Cd in grains but the Cd content was acutely lower than the PTMI limit.
The present study has monitored twelve phthalate esters (PAEs) in commercial packaged milk and milk packets in eastern India. The study results indicate that all branded milk samples were ...contaminated with PAEs. Dibutylphthalate and bis(2-ethylhexyl) phthalate were the two most prominent species in both milk packet and packaged milk contributing about 47% of the total milk-PAEs content. This result indicates that the contamination of PAEs in milk may not be the only source from milk packets but that other sources such as milk processing and packaging may have also had a role. Monte Carlo simulations were run to check the certainty level of the estimated non-carcinogenic and carcinogenic health risks from PAEs. The PAEs concentration in milk was the determining variable (sensitivity > 95%) for health risk estimation. No significant non-carcinogenic or carcinogenic health risk was expected for the population at large from exposure to toxic PAEs at the observed level due to long-term consumption of these branded packaged milk.
The debated vascular risk potential of total homocysteine (tHcy), due to failed clinical trials designed on B vitamin supplementation, raises many possible explanations like the higher risk potential ...of the deleterious, free form of homocysteine (fHcy) or, the unchecked confounding effects of B-vitamins in tHcy-based association studies. Additionally, the cardiovascular risk probability of altered status of the homocysteine precursor, methionine (tMet) could shed light on the causality of association between tHcy and cardiovascular diseases. Hence, we aimed to evaluate the risk associations of elevated plasma levels of tHcy, fHcy and low levels of tMet with premature, ischemic stroke.
We recruited 171 young, ischemic stroke patients (aged ≤45 years) and 249 age- and gender-matched healthy controls. Plasma levels of fHcy, tHcy, tMet and vitamin B6 were estimated using HPLC coupled with coulometric electrochemical detection. Plasma levels of vitamin B12 and folate were estimated by radioimmunoassay.
Elevated fHcy (>2.9 μmol/L) was independently and strongly associated with the risk of premature, ischemic stroke (OR = 9.62, 95% CI = 3.51–26.40). On the contrary, association between premature ischemic stroke and elevated tHcy (>15.0 μmol/L) was found to attenuate when adjusted for vitamin B6 values (OR = 0.24, 95%, CI = 0.03–1.69). Interestingly, compromised B6-status (<59.2 nmol/l) was found to confer high risk of premature ischemic stroke (OR = 170.80, 95% CI = 58.22–501.06). We could not establish any significant correlation between fHcy and B-vitamin levels (P > 0.05). Low tMet (<13.86 μmol/L) was also not significantly associated with premature, ischemic stroke (OR = 2.53, 95% CI = 0.613–10.38).
Our results indicate significant but not-correlated, independent associations of fHcy and vitamin B6 with risk of premature, ischemic stroke. However, the causality of these associations need prospective and large scale validations. Further, our findings highlight the crucial confounding effects of B-vitamins on risk association between tHcy and premature ischemic stroke.
Constant exposure of the living ecosystems to heavy metals, like cadmium (Cd), induces a detectable change at the biochemical and genetic level. Repeated application of phosphate fertilizers in paddy ...fields, leads to increase in Cd content of soil. Cd being highly mobile is transported to shoot and grain, thereby entering into the food chain of animal system. In the present study, treatment of 7-day old rice seedlings with 10 μM cadmium chloride resulted in Cd toxicity across the seven non-aromatic and six aromatic rice cultivars and landraces used for the study. Free proline and malondialdehyde content of treated samples were higher in comparison to the untreated samples, which indicated Cd induced tissue damage in plants. Photosynthetic pigment content of treated samples was also found to be much lower in comparison to the untreated samples, which is probably due to peroxidation of membrane, leading to compromised and lower photosynthetic efficiency of treated plants. At the genetic level, Randomly Amplified Polymorphic DNA assay was found to efficiently detect the genetic polymorphisms (caused by alterations in DNA bases) induced by Cd. Production of unique polymorphic bands in Cd-treated plants helps in assessment of the degree of damage Cd imparts on the plant system. Cluster analysis was performed and the rice genotypes were grouped into five distinct clusters, with IR64 and Tulsibhog in two distinct groups. Based on the variability in responses, the 13 rice genotypes were grouped into sensitive and tolerant ones.
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