Harnessing the power of bacterial laccases for xenobiotic degradation in water: A 10-year overview

Industrialization and population growth are leading to the production of significant amounts of sewage containing hazardous xenobiotic compounds. These compounds pose a threat to human and animal health, as well as the overall ecosystem. To combat this issue, chemical, physical, and biological techniques have been used to remove these contaminants from water bodies affected by human activity. Biotechnological methods have proven effective in utilizing microorganisms and enzymes, particularly laccases, to address this problem. Laccases possess versatile enzymatic characteristics and have shown promise in degrading different xenobiotic compounds found in municipal, industrial, and medical wastewater. Both free enzymes and crude enzyme extracts have demonstrated success in the biotransformation of these compounds. Despite these advancements, the widespread use of laccases for bioremediation and wastewater treatment faces challenges due to the complex composition, high salt concentration, and extreme pH often present in contaminated media. These factors negatively impact protein stability, recovery, and recycling processes, hindering their large-scale application. These issues can be addressed by focusing on large-scale production, resolving operation problems, and utilizing cutting-edge genetic and protein engineering techniques. Additionally, finding novel sources of laccases, understanding their biochemical properties, enhancing their catalytic activity and thermostability, and improving their production processes are crucial steps towards overcoming these limitations. By doing so, enzyme-based biological degradation processes can be improved, resulting in more efficient removal of xenobiotics from water systems. This review summarizes the latest research on bacterial laccases over the past decade. It covers the advancements in identifying their structures, characterizing their biochemical properties, exploring their modes of action, and discovering their potential applications in the biotransformation and bioremediation of xenobiotic pollutants commonly present in water sources.

Efficacy of pentamidine-loaded chitosan nanoparticles as a novel drug delivery system for Leishmania tropica

The present study compares the in vitro effects of nanoparticles loaded pentamidine drug and conventional pentamidine on Leishmania tropica. Herein, pentamidine-loaded chitosan nanoparticles (PTN-CNPs) have been synthesized through an ionic gelation method with sodium tripolyphosphate (TPP). Next, the physical characteristics of PTN-CNPs were determined through the surface texture, zeta potential, in vitro drug release, drug loading content (DLC), and encapsulation efficacy (EE) and compared its efficacy with free pentamidine (PTN) drug against promastigotes and axenic amastigotes forms of L. tropica in vitro. The PTN-CNPs displayed a spherical shape having a size of 88 nm, an almost negative surface charge (-3.09 mV), EE for PTN entrapment of 86%, and in vitro drug release of 92% after 36 h. In vitro antileishmanial activity of PTN-CNPs and free PTN was performed against Leishmania tropica KWH23 promastigote and axenic amastigote using 3-(4, 5- dimethylthiazol-2-yl)-2, 5-diphenyletetrazolium bromide (MTT) assay. It was observed that the effect of PTN-CNPs and free PTN on both forms of the parasite was dose and time dependent. Free PTN presented low efficacy even at higher dose (40 µg/ml) with 25.6 ± 1.3 and 26.5 ±1.4 mean viability rate of the promastigotes and axenic amastigotes, respectively after 72 hrs incubation. While PTN-CNPs showed strong antileishmanial effects on both forms of parasite with 16 ± 0.4 and 19 ± 0.7 mean viability rate at the same higher concentration (40 µg/ml) after 72 hrs incubation. Half maximal inhibitory concentration (IC50) values of PTN-CNPs toward promastigotes and amastigotes were obtained as 0.1375 µg/ml and 0.1910 µg/ml, respectively. In conclusion, PTN-CNPs effectively inhibited both forms of the L. tropica; however, its effect was more salient on promastigotes. This data indicates that the PTN-CNPs act as a target drug delivery system. However, further research is needed to support its efficacy in animal and human CL.

1097 17 Years of Treating Deep Sternal Wound Infections at A Single Institution: Outcomes and Lessons Learned

Introduction

Deep sternal wound infections (DSWI) are a serious complication following cardiac surgery that comprise of any infection penetrating the subcutaneous tissue of the sternum. DSWI have been found to increase mortality and worsen prognostic outcomes following surgery.

Method

We conducted a retrospective cohort study using hospital e-records from 2000 to 2017 of all adult patients operated on with a median sternotomy at our institution. Univariate and multivariate analysis along with mortality and Kaplan-Meier survival curves compared the DSWI population against the remaining study population, using SPSS-25 software.

Results

Of 15521 total patients in the study, 145 (0.9%) suffered a DSWI. Variables that were associated with DSWI included age at operation (p = 0.019), gender (p = 0.007), BMI (p = 0.001), diabetes (p < 0.0001), renal disease (p = 0.008), operative urgency (p = 0.007), type of operation (p = 0.02), Euroscore (p = <0.0001), bypass-time (p = 0.038) and crossclamp-time (p = 0.008). A logistic regression encompassing significant variables revealed that gender (p = 0.031 CI 1.45-1.96), BMI (p < 0.0001 CI 1.03-1.10), diabetes (p = 0.007 CI 1.20-3.67) and type of operation (p = 0.018 CI 1.23-1.87) remained significant when covariate contribution was eliminated. DSWI subgroup mortality was insignificant at 30 days (3.4%vs2.9%, p = 0.68) but significantly worse at 90 days (8.3%vs3.7%, p = 0.004) and at 1 year (17.2%vs5.4%, p < 0.0001). Kaplan-Meier analysis depicted a significantly worse survival distribution for the DSWI population compared to rest of study (Log-Rank<0.05).

Conclusions

At our centre, DSWI are attributable to certain modifiable and set demographics and contribute heavily to medium-term mortality. A better understanding of DSWI risk factors may pinpoint those at risk and benefit the multidisciplinary team to ultimately reduce the rate of DSWI.

302 Is Age Just A Number in Cardiac Surgery? Evaluating Outcomes of An Octogenarian Cohort at A Single Cardiac Centre

Introduction

Cardiac surgery in octogenarians contains many age-specific perioperative risk factors and outcomes yet to be fully understood.

Method

All adults (N = 4957) undergoing cardiac surgery between 2011-2017 at our institution were retrospectively studied, encompassing 312 octogenarians. Data was evaluated with univariate and multivariate testing and mortality with Kaplan-Meier and cox-regression analyses.

Results

Compared to septuagenarians, octogenarians revealed more patients having previous surgery (p = 0.016), less diabetic patients (p = 0.034), lower BMI (0.002), and longer hospital stay (p < 0.000). Compared to rest of study, octogenarians contained more females (p = 0.012), a greater Euroscore (p < 0.000), spent longer in ITU (p = 0.001) and contained more ITU readmissions (p = 0.023). The octogenarians did not contain significant 30- and 90-day mortality but revealed significant mortality at 1-year versus septuagenarians (p = 0.039) and rest of study (p = 0.001). Variables testing significant in a multivariate regression were inserted into a cox-regression that found octogenarian group-membership to be insignificant (p = 0.051) in a 12-covariate model. Independent risk factors for mortality included emergency surgery (p = 0.04), reoperation (p < 0.000), cardiac procedure (p = 0.007), ITU time (p = 0.041) and diabetes (p = 0.023).

Conclusions

We report specific differences for octogenarians in perioperative characteristics along with promising short- and medium-term survival. Such outcomes must constantly be monitored so that cardiac surgery can be further tailored to this elderly cohort.

Per-Cutaneous Trans-splenic Vein Thrombolysis of Acute Major Portal Vein Thrombosis in Post-Liver Transplant Recipient: A Unique Experience

Portal venous thrombosis (PVT) is an uncommon complication in post-liver transplant recipients. The reported incidence is 1-4%. It may occur within a month, called early or after one month of transplantation, known as late PVT. Early PVT has a poor prognosis, leading to graft failure in most cases. Treatment of such cases is quite challenging because of difficult alternative portal inflow establishment. We performed successful thrombolysis of acute major PVT with a unique technique using ultrasound-guided percutaneous trans-splenic vein access in a post-liver transplant recipient. The per-cutaneous trans- splenic vein approach-based thrombolysis described here in this report might be very helpful in similar cases. This technique minimizes the potential risk of graft loss, avoids re-exploration, has a low risk of bleeding, and is cost-effective.

Diagnostic approaches and potential therapeutic options for coronavirus disease 2019

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in Wuhan city of China in late December 2019 and identified as a novel coronavirus. Due to its contagious nature, the virus spreads rapidly and causes coronavirus disease 2019 (COVID-19). The global tally of COVID-19 was 28 million in early September 2020. The fears and stress associated with SARS-CoV-2 has demolished the socio-economic status worldwide. Researchers are trying to identify treatments, especially antiviral drugs and/or vaccines, that could potentially control the viral spread and manage the ongoing unprecedented global crisis. To date, more than 300 clinical trials have been conducted on various antiviral drugs, and immunomodulators are being evaluated at various stages of COVID-19. This review aims to collect and summarize a list of drugs used to treat COVID-19, including dexamethasone, chloroquine, hydroxychloroquine, lopinavir/ritonavir, favipiravir, remdesivir, tociluzimab, nitazoxanide and ivermectin. However, some of these drugs are not effective and their use has been suspended by WHO.

CO2 capture through electro-conductive adsorbent using physical adsorption system for sustainable development

The most critical energy and environmental challenge that our planet is facing today is to minimize the dependence on fossil fuels. Carbon dioxide may be of utmost significance as a solution of this issue through realization of carbon neutral energy cycle. Potentially, this could be achieved through the carbon dioxide capture as the urgent response to ongoing climate change. Activated carbon (AC) adsorption is one the most effective, environment friendly and techno-economic process for the carbon capture. In the current research, an electro-conductive-activated carbon was prepared by mixing powdered activated carbon (PAC) with an electro-conductive polymer (ECP). Different ratios of 0, 25, 50, 75 and 100 wt% of ECP with PAC were used for the different analyses of activated carbons in a gas mixture of CO₂/N₂ using a physical adsorption system. Adsorption and desorption analyses, capacities of the process and desorption effects were examined. Electro-conductive polymers (ECP) were mixed with AC samples, where breakthrough time was increased up to 400% when mixed with the PAC for CO₂ adsorption. Following adsorption analysis, desorption of activated carbons was conducted with different potentials. It was revealed that mixing could help the PAC sample to overcome the packing issue to increase the breakthrough capacity and the volumes before and after the breakthrough adsorption in the packed bed systems. The desorption rates of the PAC sample were also enhanced, and fast desorption was observed when mixed with ECP. It is envisioned that this method is very much promising carbon capture method for the techno-economic feasibility and sustainable development of the environment.

Adulticidal Activity of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under Laboratory Conditions

BACKGROUND

There are several plant extractions which are being used for mosquito control. The aim of this study was to evaluate the efficacy of Olea vera, Linum usitatissimum and Piper nigera against Anopheles stephensi and Aedes aegypti under laboratory conditions.

METHODS

These tests were carried out using WHO recommended bioassay method for adult mosquitoes.

RESULTS

The extracts from black pepper was more effective as adulticide with lowest LC(50) values (2.26% and 8.4%) against Aedes aegypti and Anopheles stephensi after 24 h of exposure while after 48h (1.56% and 5.11%) respectively. In terms of LC(90) value black pepper was best with (8.66% and 30.1%) against Ae. aegypti and An. stephensi after 24 h of exposure while after 48h (4.59% and 17.3%) respectively. In terms of LT(50) black pepper took 15 h to kill 50% tested population of Ae. aegypti while against An. stephensi it took more than 2 days. In terms of percentage mortality black pepper kill 84% of the population of Ae. aegypti and 44.75% of the An. stephensi population.

CONCLUSION

Black pepper showed best results in term of LC(50), LC(90), LT(50) and percentage mortality against Ae. aegypti and An. stephensi. Our study suggested that the plant extracts have potential to kill adult mosquitoes, are environment friendly and can be used for the control of mosquitoes.