Biodegradation of polyethylene and polystyrene by Zophobas atratus larvae from Bangladeshi source and isolation of two plastic-degrading gut bacteria.

Plastic pollution has become a major environmental concern globally, and novel and eco-friendly approaches like bioremediation are essential to mitigate the impact. Low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and expanded polystyrene (EPS) are three of the most frequently used plastic types. This study examined biodegradation of these using Zophobas atratus larvae, followed by isolation and whole genome sequencing of gut bacteria collected from larvae frass. Over 36 days, 24.04 % LDPE, 20.01 % EPS, and 15.12 % LLDPE were consumed on average by the larvae, with survival rates of 85 %, 90 %, and 87 %, respectively. Fourier transform infrared spectroscopy (FTIR) analysis of fresh plastic types, consumed plastics, and larvae frass showed proof of plastic oxidation in the gut. Frass bacteria were isolated and cultured in minimal salt media supplemented with plastics as the sole carbon source. Two isolates of bacteria were sampled from these cultures, designated PDB-1 and PDB-2. PDB-1 could survive on LDPE and LLDPE as carbon sources, whereas PDB-2 could survive on EPS. Scanning Electron Microscopy (SEM) provided proof of degradation in both cases. Both isolates were identified as strains of Pseudomonas aeruginosa, followed by sequencing, assembly, and annotation of their genomes. LDPE- and LLDPE-degrading enzymes e.g., P450 monooxygenase, alkane monooxygenase, alcohol dehydrogenase, etc. were identified in PDB-1. Similarly, phenylacetaldehyde dehydrogenase and other enzymes involved in EPS degradation were identified in PDB-2. Genes of both isolates were compared with genomes of known plastic-degrading P. aeruginosa strains. Virulence factors, antibiotic-resistance genes, and rhamnolipid biosurfactant biosynthesis genes were also identified in both isolates. This study indicated Zophobas atratus larvae as potential LDPE, LLDPE, and EPS biodegradation agent. Additionally, the isolated strains of Pseudomonas aeruginosa provide a more direct and eco-friendly solution for plastic degradation. Confirmation and modification of the plastic-degrading pathways in the bacteria may create scope for metabolic engineering in the future.

Bioethanol production using vegetable peels medium and the effective role of cellulolytic bacterial (Bacillus subtilis) pre-treatment.

Background:  The requirement of an alternative clean energy source is increasing with the elevating energy demand of modern age. Bioethanol is considered as an excellent candidate to satiate this demand. Methods: Yeast isolates were used for the production of bioethanol using cellulosic vegetable wastes as substrate. Efficient bioconversion of lignocellulosic biomass into ethanol was achieved by the action of cellulolytic bacteria ( Bacillus subtilis).  After proper isolation, identification and characterization of stress tolerances (thermo-, ethanol-, pH-, osmo- & sugar tolerance), optimization of physiochemical parameters for ethanol production by the yeast isolates was assessed. Very inexpensive and easily available raw materials (vegetable peels) were used as fermentation media. Fermentation was optimized with respect to temperature, reducing sugar concentration and pH. Results: It was observed that temperatures of 30°C and pH 6.0 were optimum for fermentation with a maximum yield of ethanol. The results indicated an overall increase in yields upon the pretreatment of Bacillus subtilis; maximum ethanol percentages for isolate SC1 obtained after 48-hour incubation under pretreated substrate was 14.17% in contrast to untreated media which yielded 6.21% after the same period. Isolate with the highest ethanol production capability was identified as members of the ethanol-producing Saccharomyces species after stress tolerance studies and biochemical characterization using Analytical Profile Index (API) ® 20C AUX and nitrate broth test. Introduction of Bacillus subtilis increased the alcohol production rate from the fermentation of cellulosic materials. Conclusions: The study suggested that the kitchen waste can serve as an excellent raw material in ethanol fermentation.

Unión de Desloratadina y Atenolol con Albúmina Sérica Bovina y sus interacciones in vitro / Binding of desloratadine and atenolol with bovine serum albumin and their in-vitro interactions

Objetivo: Unir atenolol, antagonista selectivo de los receptores beta1, y desloratadina, antagonista de los receptores H1, a albúmina sérica bovina. Método: El análisis de la unión se analizó mediante diálisis de equilibrio utilizando ranitidina y diazepam como sondas específicas para el sitio I y sitio II respectivamente. Resultados: Los resultados sugirieron dos conjuntos de constantes de asociación. Para el atenolol: constante de asociación con afinidad elevada (k1 = 5 x 10-5 M-1) con baja capacidad (n1 = 2) y constante de asociación con afinidad baja (k2 = 5 x 10-5 M-1) con alta capacidad (n2 = 5), mientras que para la desloratadina: constante de afinidad de asociación elevada (k1 = 45 x 10-5 M-1) con baja capacidad (n1 = 1,3) y constante de afinidad de asociación baja (k2= 5 x 10-5 M-1) con alta capacidad (n2 = 2,5), a un pH 7,4 y 27 °C. Tras la administración conjunta de atenolol y desloratadina en presencia o ausencia de ranitidina o diazepam, la desloratadina provocó la liberación del atenolol de su sitio de unión a la albúmina sérica bovina, provocando una disminución de la unión del atenolol a la albúmina sérica bovina. La fracción libre de atenolol incrementó del 84,1% al 99% y la concentración de la desloratadina de 0 x 10-5 M a 14 x 10-5 M. En presencia de diazepam como sonda específica para el sitio II, la desloratadina incrementó la fracción libre de atenolol del 0,45% to 14,3%. Conclusión: Los datos obtenidos indican la interacción de concentraciones elevadas de desloratadina a los sitios de unión de la albúmina sérica bovina modificando las propiedades farmacocinéticas del atenolol(AU)

Aims: The binding of atenolol a selective beta1 receptor antagonist and desloratadine, an H1 receptor antagonist, to bovine serum albumin. Methods: The analysis of binding was studied by equilibrium dialysis method (ED) using ranitidine and diazepam as site-1 and site-2 specific probe, respectively. Results: The study suggested two sets of association constants, for atenolol: high affinity association constant (k1 = 5 x 10-5 M-1) with low capacity (n1 = 2) and low affinity association constant (k2 = 2.5 x 10-5 M-1) with high capacity (n2 = 5), while for desloratadine: high affinity association constant (k1 = 45 x 10-5 M-1) with low capacity (n1 = 1.3) and low affinity association constant (k2 = 5 x 10-5 M-1) with high capacity (n2 = 2.5) at pH 7.4 and 27 ºC. During concurrent administration of atenolol and desloratadine in presence or absence of ranitidine or diazepam, desloratadine causes the release of atenolol from its binding site on BSA resulting reduced binding of atenolol to BSA. The increment in free fraction of atenolol was from 84.01% to 99 % upon the addition of increased concentration of only desloratadine at a concentration of 0 x 10-5 M to 14 x 10-5 M. In presence of diazepam as site-II specific probes, desloratadine further increases the free fraction of atenolol was from 0.45% to 14.3%. Conclusion: These data were indicative for the interaction of higher concentration of desloratadine at the binding sites on BSA changing the pharmacokinetics properties of atenolol (AU)

Antimicrobials resistance pattern of Escherichia coli collected from various pathological specimens.

Irrational use of antibiotics is common in Bangladesh. The purpose of the present study was to know the effectiveness of various commonly used antimicrobials against Escherichia coli. Antimicrobial susceptibility test was done by Disc Diffusion method. In this study, antimicrobial resistance pattern of 163 isolates of Escherichia coli collected from various pathological specimens were determined. Most of the isolates (77%) were collected from urine sample. The highest numbers of isolates were resistant to cloxacillin (96.93%) and the lowest number isolates were resistant to imipenem (5.52%). Out of 163 isolates 141 (86.5%) were resistant to ampicillin, 89 (54.60%) to ceftazidime and 88 (53.99%) to ceftriaxone. From this study, it also appears that third generation cephalosporins (ceftazidime and ceftriaxone) were more effective against the test isolates in comparison to penicillin. The present study also revealed that 113 (69.33%) isolates were resistant to ciprofloxacin, 92 (56.44%) to chloramphenicol, 121 (74.23%) to co-trimoxazole and 128 (78.53%) to nalidixic acid. To the aminoglycoside drug 58 (35.58%) isolates were resistant to gentamicin and 74 (45.40%) to netilmicin. In this study 138 (84.66%) isolates were resistant to doxycycline, 126 (77.30%) isolates were resistant to tetracycline. Four isolates showed resistance to all the antimicrobials used except to imipenem. In the present study imipenem was found to be the most effective and 154 out of 163 isolates (94.48%) were found to be sensitive and cloxacillin was least effective and only 5 out of 163 isolates (3.07%) were sensitive to this penicillinase resistant drug.