Genomic and biotechnological potential of a novel oil-degrading strain Enterobacter kobei DH7 isolated from petroleum-contaminated soil

In this study, a novel oil-degrading strain Enterobacter kobei DH7 was isolated from petroleum-contaminated soil samples from the industrial park in Taolin Town, Lianyungang, China. The whole genome of the strain was sequenced and analyzed to reveal its genomic potential. The oil degradation and growth conditions including nitrogen, and phosphorus sources, degradation cycle, biological dosing, pH, and oil concentration were optimized to exploit its commercial application. The genome of the DH7 strain contains 4,705,032 bp with GC content of 54.95% and 4653 genes. The genome analysis revealed that there are several metabolic pathways and enzyme-encoding genes related to oil degradation in the DH7 genome, such as the paa gene cluster which is involved in the phenylacetic acid degradation pathway, and complete degradation pathways for fatty acid and benzoate, genes related to chlorinated alkanes and olefins degradation pathway including adhP, frmA, and adhE, etc. The strain DH7 under the optimized conditions has demonstrated a maximum degradation efficiency of 84.6% after 14 days of treatment using synthetic oil, which comparatively displays a higher oil degradation efficiency than any Enterobacter species known to date. To the best of our knowledge, this study presents the first-ever genomic studies related to the oil degradation potential of any Enterobacter species. As Enterobacter kobei DH7 has demonstrated significant oil degradation potential, it is one of the good candidates for application in the bioremediation of oil-contaminated environments.

Strategies for efficient management of microplastics to achieve life cycle assessment and circular economy

The anticipated increase in the influx of plastic waste into aquatic environments has propelled the identification and elimination of plastic waste into the global agenda. The plastics sector generates a significant volume of materials, which, due to their extended durability, accumulate rapidly in natural ecosystems. Consequently, this indiscriminate utilization, along with the deposition of plastic waste (PW) in landfills and inadequate recycling practices, leads to diverse economic, social, and environmental consequences. Microplastics (MPs) are a type of PW that has been fragmented into particles measuring less than 5 mm. These particles have been found in several environments, including the air, soil, freshwater, and ocean ecosystems, where they accumulate in large quantities. In order to gain insight into the ecological risks and resource implications associated with a plastic product, it is strongly advised to conduct life cycle and sustainability analyses. Therefore, this paper examines various strategies aimed at achieving effective management of MP waste in order to develop a conceptual framework for MPs in circular economy and life cycle assessment (LCA). The findings of this study provides a new avenue for future research and contribution to manage MP waste as well as reduce their environmentally hazardous impact.

Astaxanthin production from the microalga Haematococcus lacustris with a dual substrate mixotrophy strategy

This study investigates the development of dual-substrate mixotrophy strategy to cultivate the microalga Haematococcus lacustris for astaxanthin production. The influence of different concentrations of acetate and pyruvate on biomass productivity was first assessed individually, and then both substrates were used together to improve biomass growth in the green phase and astaxanthin accumulation in red the phase. The results showed that dual-substrates mixotrophy significantly increased the biomass productivity during green growth phase up to 2-fold compared to phototrophic controls. Furthermore, supplementation of dual-substrate to the red phase increased astaxanthin accumulation by 10% in the dual-substrate group compared to single-substrate acetate and no substrate. This dual-substrate mixotrophy approach shows promise for cultivating Haematococcus for commercial production of biological astaxanthin in indoor closed systems.

The radiomic biomarker in non-small cell lung cancer: 18F-FDG PET/CT characterisation of programmed death-ligand 1 status

AIM

To present an integrated 2-[18F]-fluoro-2-deoxy-d-glucose (18F-FDG) positron-emission tomography (PET)/computed tomography (CT) radiomic characterisation of programmed death-ligand 1 (PD-L1) status in non-small-cell lung cancer (NSCLC).

MATERIALS AND METHODS

In this retrospective study, 18F-FDG PET/CT images and clinical data of 394 eligible patients were divided into training (n=275) and test sets (n=119). Next, the corresponding nodule of interest was segmented manually on the axial CT images by radiologists. After which, the spatial position matching method was used to match the image positions of CT and PET, and radiomic features of the CT and PET images were extracted. Radiomic models were built using five different machine-learning classifiers and the performance of the radiomic models were further evaluated. Finally, a radiomic signature was established to predict the PD-L1 status in patients with NSCLC using the features in the best performing radiomic model.

RESULTS

The radiomic model based on the PET intranodular region determined using the logistic regression classifier preformed best, yielding an area under the receiver operating characteristics curve (AUC) of 0.813 (95% CI: 0.812, 0.821) on the test set. The clinical features did not improve the test set AUC (0.806, 95% CI: 0.801, 0.810). The final radiomic signature for PD-L1 status was consisted of three PET radiomic features.

CONCLUSION

This study showed that an 18F-FDG PET/CT-based radiomic signature could be used as a non-invasive biomarker to discriminate PD-L1-positive from PD-L1-negative in patients with NSCLC.

Utilization of glycosyltransferases as a seamless tool for synthesis and modification of the oligosaccharides-A review

Glycosyltransferases (GTs) catalyze the transfer of active monosaccharide donors to carbohydrates to create a wide range of oligosaccharide structures. GTs display strong regioselectivity and stereoselectivity in producing glycosidic bonds, making them extremely valuable in the in vitro synthesis of oligosaccharides. The synthesis of oligosaccharides by GTs often gives high yields; however, the enzyme activity may experience product inhibition. Additionally, the higher cost of nucleotide sugars limits the usage of GTs for oligosaccharide synthesis. In this review, we comprehensively discussed the structure and mechanism of GTs based on recent literature and the CAZY website data. To provide innovative ideas for the functional studies of GTs, we summarized several remarkable characteristics of GTs, including folding, substrate specificity, regioselectivity, donor sugar nucleotides, catalytic reversibility, and differences between GTs and GHs. In particular, we highlighted the recent advancements in multi-enzyme cascade reactions and co-immobilization of GTs, focusing on overcoming problems with product inhibition and cost issues. Finally, we presented various types of GT that have been successfully used for oligosaccharide synthesis. We concluded that there is still an opportunity for improvement in enzymatically produced oligosaccharide yield, and future research should focus on improving the yield and reducing the production cost.

[Comparison on the efficacy of Chinese-made novel-designed mechanical-locked and elastic self-locked transcatheter edge-to-edge repair system in the treatment of patients with functional mitral regurgitation]

Objective: To evaluate and compare the short-term efficacy of domestic mechanical-locked (Clip2Edge) and elastic self-locked (ValveClip) transcranial mitral valve edge-to-edge interventional repair (TEER) devices in the treatment of functional mitral regurgitant valves. Methods: In this retrospective non-randomized comparative study, patients underwent TEER procedure in Fuwai Yunnan Cardiovascular Disease Hospital from May 2022 to April 2023 for heart failure combined with moderate to severe or severe functional mitral valve were divided into Clip2Edge and ValveClip groups based on the TEER system used. Baseline, perioperative, and postoperative 30 d follow-up data were collected and compared between the two groups. The primary outcome was the success rate on the 30 d post operation, while secondary outcomes included immediate postoperative technical success rate and the incidence of all-cause mortality on the 30 d post operation, readmission rate of acute heart failure, cerebral infarction, severe bleeding, and other serious adverse events rates. Results: A total of 60 patients were enrolled, 34 patients were in the Clip2Edge group and 26 in the ValveClip group, mean age was (63.8±9.3) years, and 24 patients (40%) were female. There were no significant differences in baseline data of age, cardiac function, comorbidities, mitral regurgitation 4+(19(73%) vs. 29(85%)), the end-diastolic volume of left ventricle ((220.8±91.2) ml vs. (210.8±71.7) ml) between the two groups (all P>0.05). The technical success rate immediately after the procedure was 100%. There were no readmission of acute heart failure, death, cerebral infarction, severe bleeding, and other serious adverse events up to the 30 d follow-up. Device success rate was similar between the ValveClip group (24 cases (100%)) and the Clip2Edge group (27 cases (96%)) (P>0.05). Conclusion: Both types of novel domestic TEER devices are safe and feasible in treating patients with functional mitral regurgitation.

[The target value of anticoagulation intensity for Chinese patients after mechanical heart valve replacement]

Objective: To explore the optimal intensity of anticoagulation therapy for Chinese patients after mechanical heart valve replacement. Methods: This is a prospective, multicenter, cohort study. The anticoagulation data from in-hospital patients of 35 medical centers and patients in outpatient clinic of 11 medical centers from Anticoagulation Therapy Database of Chinese Patients after Heart Valve Replacement between January 2011 and December 2015 were analyzed. The anticoagulation-relevant complications among different coagulation intensities were compared, and the optimal value of anticoagulation intensity for Chinese patients after mechanical heart valve replacement were analyzed. Results: A total of 24 433 patients were in the final analysis, including 13 634 females and 10 799 males, with a median age of 49.0 (3-80) years. International normalized ratio (INR) values of in-hospital patients were recorded 94 286 times, with the mean value of 1.8±0.7, and 87.6% (82 595/94 286) of them were within the range of 1.5 to 2.5. During a median follow-up time of 19.2 (1.0-58.8) months, a total of 17 331 outpatient clinic patients were followed up, with the follow-up rate of 89.1% (17 331/19 452) and a total of 27 803 patient-years (Pty), including 4 038 aortic valve replacement (AVR), 8 215 mitral valve replacement (MVR), 4 437 AVR plus MVR (double valve replacement, DVR) replacement and 641 tricuspidvalve replacement (TVR). A total of 101 860 INR measurements were recorded, with the mean value of 1.8±0.5, and 64.8% (66 005/101 860) of them were within the range of 1.5-2.5. The rates of anticoagulation-related complications of the patients with INR of 1.5-2.5 (0.65/100 Pty) were lower than those of other INR value patients (INR<1.5: 1.31/100 Pty, RR=2.01, 95%CI: 1.59-2.51, P<0.001; INR>2.5: 2.34/100 Pty, RR=3.60, 95%CI: 2.84-4.52, P<0.001). The rates of anticoagulation-related complications of AVR and MVR patients without risk factors and with INR of 1.5-2.0 were lower than those of other INR value patients (AVR: 0.15/100 Pty vs 0.38/100 Pty, RR=2.57, 95%CI: 1.02-7.28, P=0.029; MVR: 0.23/100 Pty vs 0.56/100 Pty, RR=2.42, 95%CI: 1.39-4.38, P<0.001), and the rate of anticoagulation-related complications of DVR patients with INR of 2.0-2.5 was lower than those of other INR value patients (0.32/100 Pty vs 0.62/100 Pty, RR=1.94, 95%CI: 1.03-3.79, P=0.029). Conclusions: A target INR range of 1.5-2.5 is recommended for Chinese patients after mechanical heart valve replacement. The optimal INR value for isolated AVR or MVR patients without risk factors was 1.5-2.0, while the optimal INR value for isolated AVR or MVR patients with risk factors and all the TVR or DVR patients was 2.0-2.5.

Bioplastic production in terms of life cycle assessment: A state-of-the-art review

The current transition to sustainability and the circular economy can be viewed as a socio-technical response to environmental impacts and the need to enhance the overall performance of the linear production and consumption paradigm. The concept of biowaste refineries as a feasible alternative to petroleum refineries has gained popularity. Biowaste has become an important raw material source for developing bioproducts and biofuels. Therefore, effective environmental biowaste management systems for the production of bioproducts and biofuels are crucial and can be employed as pillars of a circular economy. Bioplastics, typically plastics manufactured from bio-based polymers, stand to contribute to more sustainable commercial plastic life cycles as part of a circular economy in which virgin polymers are made from renewable or recycled raw materials. Various frameworks and strategies are utilized to model and illustrate additional patterns in fossil fuel and bioplastic feedstock prices for various governments' long-term policies. This review paper highlights the harmful impacts of fossil-based plastic on the environment and human health, as well as the mass need for eco-friendly alternatives such as biodegradable bioplastics. Utilizing new types of bioplastics derived from renewable resources (e.g., biowastes, agricultural wastes, or microalgae) and choosing the appropriate end-of-life option (e.g., anaerobic digestion) may be the right direction to ensure the sustainability of bioplastic production. Clear regulation and financial incentives are still required to scale from niche polymers to large-scale bioplastic market applications with a truly sustainable impact.

[BCS1Neonatal growth retardation and lactic acidosis initiated by novel mutation sites in L gene]

This study aims to analyze the clinical characteristics and genetic variations of two cases with developmental delay and lactic acidosis in a family, and to explore the relationship between genetic variations and clinical features. A retrospective analysis was conducted on the clinical characteristics of two siblings with developmental delay and lactic acidosis who were treated at the Neonatal Department of Children's Hospital of Chongqing Medical University in May 2019 and December 2021, respectively. Whole-exome sequencing was used to detect genetic variations in the affected children. Homology modeling of the BCS1L protein was performed to analyze the structural and functional changes of the protein. The correlation between genetic variations and clinical phenotypes was analyzed. The results showed that the main clinical features of the two affected children in this family were manifestations of mitochondrial respiratory chain complex Ⅲ deficiency, including prematurity, developmental delay, respiratory failure, lactic acidosis, cholestasis, liver dysfunction, renal tubular lesions, coagulation dysfunction, anemia, hypoglycemia, hypotonia, and early death. Whole-exome sequencing revealed a novel deletion mutation c.486_488delGGA (p.E163del) and a novel missense mutation c.992C>T (p.T331I) in the BCS1L gene. Structural analysis of the homology modeling showed that the compound heterozygous mutation had a significant impact on protein function. In conclusion, the novel mutation site c.992C>T (p.T331I) in the BCS1L gene is a "likely pathogenic" mutation, and the compound heterozygous mutation is closely related to the phenotype of mitochondrial respiratory chain complex Ⅲ deficiency.

Optimization of heterologous production of Bacillus ligniniphilus L1 laccase in Escherichia coli through statistical design of experiments

Laccases are powerful multi-copper oxidoreductases that have wide applicability as "green" biocatalysts in biotechnological, bioremediation, and industrial applications. Sustainable production of large amounts of functional laccases from original sources is limited by low yields, difficulties in purification, slow growth of the organisms, and high cost of production. Harnessing the full potential of these versatile biocatalysts will require the development of efficient heterologous systems that allow high-yield, scalable, and cost-effective production. We previously cloned a temperature- and pH-stable laccase from Bacillus ligniniphilus L1 (L1-lacc) that demonstrated remarkable activity in the oxidation of lignin and delignification for bioethanol production. However, L1-lacc is limited by low enzyme yields in both the source organism and heterologous systems. Here, to improve production yields and lower the cost of production, we optimized the recombinant E. coli BL21 strain for high-level production of L1-lacc. Several culture medium components and fermentation parameters were optimized using one-factor-at-a-time (OFAT) and Plackett-Burman design (PBD) to screen for important factors that were then optimized using response surface methodology (RSM) and an orthogonal design. The optimized medium composition had compound nitrogen (15.6 g/L), glucose (21.5 g/L), K₂HPO₄ (0.15 g/L), MgSO₄ (1 g/L), and NaCl (7.5 g/L), which allowed a 3.3-fold yield improvement while subsequent optimization of eight fermentation parameters achieved further improvements to a final volumetric activity titer of 5.94 U/mL in 24 h. This represents a 7-fold yield increase compared to the initial medium and fermentation conditions. This work presents statistically guided optimization strategies for improving heterologous production of a bacterial laccase that resulted in a high-yielding, cost-efficient production system for an enzyme with promising applications in lignin valorization, biomass processing, and generation of novel composite thermoplastics.

Intravenous N-acetylcysteine in respiratory disease with abnormal mucus secretion

OBJECTIVE

Evidence for the mucolytic and expectorant efficacy of intravenous (IV) N-acetylcysteine (NAC) is limited. This study aimed to evaluate in a large, multicenter, randomized, controlled, subject, and rater-blinded study whether IV NAC is superior to placebo and non-inferior to ambroxol in improving sputum viscosity and expectoration difficulty.

PATIENTS AND METHODS

A total of 333 hospitalized subjects from 28 centers in China with respiratory disease (such as acute bronchitis, chronic bronchitis and exacerbations, emphysema, mucoviscidosis, and bronchiectasis) and abnormal mucus secretion were randomly allocated in a 1:1:1 ratio to receive NAC 600 mg, ambroxol hydrochloride 30 mg, or placebo as an IV infusion twice daily for 7 days. Mucolytic and expectorant efficacy was assessed by ordinal categorical 4-point scales and analyzed by stratified and modified Mann-Whitney U statistics.

RESULTS

NAC showed consistent and statistically significant superiority to placebo and non-inferiority to ambroxol in change from baseline to day 7 in both sputum viscosity scores [mean (SD) difference 0.24 (0.763), p<0.001 vs. placebo] and expectoration difficulty score [mean (SD) difference 0.29 (0.783), p=0.002 vs. placebo]. Safety findings confirm the good tolerability profile of IV NAC reported from previous small studies, and no new safety concerns were identified.

CONCLUSIONS

This is the first large, robust study of the efficacy of IV NAC in respiratory diseases with abnormal mucus secretion. It provides new evidence for IV NAC administration in this indication in clinical situations where the IV route is preferred.

Host-Specific Diversity of Culturable Bacteria in the Gut Systems of Fungus-Growing Termites and Their Potential Functions towards Lignocellulose Bioconversion

Fungus-growing termites are eusocial insects that represent one of the most efficient and unique systems for lignocellulose bioconversion, evolved from a sophisticated symbiosis with lignocellulolytic fungi and gut bacterial communities. Despite a plethora of information generated during the last century, some essential information on gut bacterial profiles and their unique contributions to wood digestion in some fungus-growing termites is still inadequate. Hence, using the culture-dependent approach, the present study aims to assess and compare the diversity of lignocellulose-degrading bacterial symbionts within the gut systems of three fungus-growing termites: Ancistrotermes pakistanicus, Odontotermes longignathus, and Macrotermes sp. A total of 32 bacterial species, belonging to 18 genera and 10 different families, were successfully isolated and identified from three fungus-growing termites using Avicel or xylan as the sole source of carbon. Enterobacteriaceae was the most dominant family represented by 68.1% of the total bacteria, followed by Yersiniaceae (10.6%) and Moraxellaceae (9%). Interestingly, five bacterial genera such as Enterobacter, Citrobacter, Acinetobacter, Trabulsiella, and Kluyvera were common among the tested termites, while the other bacteria demonstrated a termite-specific distribution. Further, the lignocellulolytic potential of selected bacterial strains was tested on agricultural waste to evaluate their capability for lignocellulose bioconversion. The highest substrate degradation was achieved with E. chengduensis MA11 which degraded 45.52% of rice straw. All of the potential strains showed endoglucanase, exoglucanase, and xylanase activities depicting a symbiotic role towards the lignocellulose digestion within the termite gut. The above results indicated that fungus-growing termites harbor a diverse array of bacterial symbionts that differ from species to species, which may play an inevitable role to enhance the degradation efficacy in lignocellulose decomposition. The present study further elaborates our knowledge about the termite-bacteria symbiosis for lignocellulose bioconversion which could be helpful to design a future biorefinery.

Characterization and 3D printing of a biodegradable polylactic acid/thermoplastic polyurethane blend with laccase-modified lignin as a nucleating agent

Polylactic acid (PLA) has been used in fused deposition method (FDM) based 3D printing for many years. Alkali lignin is an undervalued industrial by-product that could upgrade PLA's poor mechanical properties. This work presents a biotechnological approach consisting of a partial degradation of alkali lignin using Bacillus ligniniphilus laccase (Lacc) L1 for its use as a nucleating agent in a polylactic acid/thermoplastic polyurethane (PLA/TPU) blend. Results showed that adding enzymatically modified lignin (EL) increased the elasticity modulus to a maximum of 2.5-fold than the control and conferred a maximum biodegradability rate of 15 % after 6 months under the soil burial method. Furthermore, the printing quality rendered satisfactory smooth surfaces, geometries and a tunable addition of a woody color. These findings open a new door for using laccase as a tool to upgrade lignin's properties and its use as a scaffold in manufacturing more environmentally sustainable filaments with improved mechanical properties for 3D printing.

Predictors of postoperative biochemical remission in lower Knosp grade growth hormone-secreting pituitary adenomas: a large single center study

PURPOSE

Growth hormone-secreting pituitary adenomas (GH-PAs) with a low Knosp grade are typically associated with a good postoperative biochemical remission (BR) rate. However, a proportion of patients do not achieve remission. In this study, we aimed to investigate predictive factors of postoperative remission for lower Knosp GH-PAs.

METHODS

In this retrospective study, we enrolled 140 patients who were diagnosed with lower Knosp (0-2) GH-PAs and received trans-sphenoidal surgery between December 2016 and June 2021 from the largest pituitary tumor surgery center in southern China. The univariate, binary Logistic regression, and receiver operating characteristic curve (ROC) analyses were employed to determine independent predictors and cutoff values of remission. The postoperative outcome was defined as remission using the 2010 consensus criteria of acromegaly.

RESULTS

One hundred and thirty six patients (97.1%) achieved gross total resection. The postoperative long-term BR was 68.6%. Empty sella, tumor maximum diameter and postoperative GH levels were independent factors predicting remission. ROC revealed that postoperative 24 h GH ≤ 1.3 ng/mL and  ≤ 1.23 ng/mL were valuable predictors for 3-month and long-term remission respectively, and that postoperative 3-month GH ≤ 1.6 ng/mL and tumor maximum diameter  ≤ 17 mm were predictors for delayed remission.

CONCLUSION

Early postoperative GH levels can be used as predictors of remission. However, BR was not associated with preoperative somatostatin analogs therapy or Knosp grade (0-2). For patients without residual tumor or recurrence and whose GH levels are slightly elevated within 1 year after surgery, adjuvant treatments may not be necessary.

CircOMA1 modulates cabergoline resistance by downregulating ferroptosis in prolactinoma

PURPOSE

Prolactinomas are one of the most common pituitary neuroendocrine tumors (PitNETs), accounting for approximately 50% of all pituitary tumors. Dopamine agonists are the main treatment for prolactinoma, but a small number of patients are still resistant to pharmacotherapy. Recent discoveries have revealed that ferroptosis is involved in regulating tumor drug resistance. However, the role of ferroptosis in prolactinoma has not been reported. In this study, we aimed to explore the mechanism of a circRNA in ferroptosis in prolactinoma.

METHODS

The expression of circOMA1 in prolactinoma tissues was examined by quantitative reverse transcription PCR (qRT-PCR). The biological function of circOMA1 was evaluated in vitro and in vivo. To explore the role of ferroptosis in prolactinoma, we used qRT-PCR and western blotting. Glutamate-cysteine ligase, modifier subunit (GCLM) was predicted to be a direct target gene of miR-145-5p by bioinformatics analysis, which was confirmed by luciferase reporter assays.

RESULTS

circOMA1 was overexpressed in drug-resistant prolactinoma tissues compared with sensitive prolactinoma samples. We further found that circOMA1 promoted MMQ cells growth in vivo and in vitro. In addition, GCLM was directly targeted by miR-145-5p and indirectly regulated by circOMA1. Importantly, circOMA1 induced ferroptosis resistance through the increased expression of Nrf2, GPX4, and xCT, and circOMA1 attenuated CAB-induced ferroptosis in MMQ cells in vivo and in vitro.

CONCLUSION

The present study demonstrates that circOMA1 attenuates CAB efficacy through ferroptosis resistance and may be a new therapeutic target for the individualized treatment of DA-resistant prolactinoma patients.

A review of microbial degradation of per- and polyfluoroalkyl substances (PFAS): Biotransformation routes and enzymes

Since the 1950s, copious amounts of per- and polyfluoroalkyl substances (PFAS) (dubbed "forever chemicals") have been dumped into the environment, causing heavy contamination of soil, surface water, and groundwater sources. Humans, animals, and the environment are frequently exposed to PFAS through food, water, consumer products, as well as waste streams from PFAS-manufacturing industries. PFAS are a large group of synthetic organic fluorinated compounds with widely diverse chemical structures that are extremely resistant to microbial degradation. Their persistence, toxicity to life on earth, bioaccumulation tendencies, and adverse health and ecological effects have earned them a "top priority pollutant" designation by regulatory bodies. Despite that a number of physicochemical methods exist for PFAS treatment, they suffer from major drawbacks regarding high costs, use of high energy and incomplete mineralization (destruction of the CF bond). Consequently, microbial degradation and enzymatic treatment of PFAS are highly sought after as they offer a complete, cheaper, sustainable, and environmentally friendly alternative. In this critical review, we provide an overview of the classification, properties, and interaction of PFAS within the environment relevant to microbial degradation. We discuss latest developments in the biodegradation of PFAS by microbes, transformation routes, transformation products and degradative enzymes. Finally, we highlight the existing challenges, limitations, and prospects of bioremediation approaches in treating PFAS and proffer possible solutions and future research directions.

Self-Assembled Microfiber-Like Biohydrogel for Ultrasensitive Whole-Cell Electrochemical Biosensing in Microdroplets

A novel microfiber-like biohydrogel was fabricated by a facile approach relying on electroactive bacteria-induced graphene oxide reduction and confined self-assembly in a capillary tube. The microfiber-like biohydrogel (d = ∼1 mm) embedded high-density living cells and activated efficient electron exchange between cells and the conductive graphene network. Further, a miniature whole-cell electrochemical biosensing system was developed and applied for fumarate detection under -0.6 V (vs Ag/AgCl) applied potential. Taking advantage of its small size, high local cell density, and excellent electron exchange, this microfiber-like biohydrogel-based sensing system reached a linear calibration curve (R² = 0.999) ranging from 1 nM to 10 mM. The limit of detection obtained was 0.60 nM, which was over 1300 times lower than a traditional biosensor for fumarate detection in 0.2 μL microdroplets. This work opened a new dimension for miniature whole-cell electrochemical sensing system design, which provided the possibility for bioelectrochemical detection in small volumes or three-dimensional local detection at high spatial resolutions.

Biodegradability of polyethylene by efficient bacteria from the guts of plastic-eating waxworms and investigation of its degradation mechanism

Polyethylene (PE) has been regarded as non-biodegradable for decades, and the evidence for its degradation by bacteria remains unclear in the literature. Waxworms have recently gained attention for their ability to degrade natural long-chain polymers and synthetic plastic. This study aims to explore the potential of low-density polyethylene (LDPE)-degrading bacteria from the gut symbionts of lesser waxworm (Achroia grisella) larvae for the effective biodegradation of LEDP. Two bacterial isolates (LDPE-DB1 and LDPE-DB2) exhibited the greatest reduction in tensile strength among all isolates (P < 0.0001), reaching 51.3% and 58.3%, respectively. The bacterial strains LDPE-DB1 and LDPE-DB2 stand for molecularly identified species, Citrobacter freundii and Bacillus sp., respectively. After 5 days of incubation, the cell density of LDPE-DB1 and LDPE-DB2 reached 2.20 × 10⁸ and 1.8 × 10⁸ CFU/mL, respectively. However, after 30 days of incubation, the cell density reached 7.3 × 10⁸ and 5.9 × 10⁸, respectively. The formed cavities indicate the high activity of the isolated bacteria from Achroia grisella larvae where the cavities reach a depth of up to 1.2 µm. The findings of this study demonstrated the presence of LDPE-degrading bacteria in Achroia grisella and provide promising evidence for the biodegradation of plastic waste management in the environment.

Straw lignin degradation by lignin peroxidase from Irpex lacteus cooperated with enzymes and small molecules

OBJECTIVES

Maximizing the utility value of enzymes was achieved by exploring the effects of small molecules on the efficiency of lignin degradation by lignin peroxidase.

METHODS

Using wheat straw as raw material and taking lignin degradation rate as index, it was found that laccase, glucose oxidase, malonic acid, citric acid, ZnSO₄, CaCl₂ could promote the lignin degradation by the lignin peroxidase from Irpex lacteus, respectively. Moreover, glucose oxidase, malonic acid and CaCl₂ had obvious synergy effects on lignin degradation by the lignin peroxidase.

RESULTS

The optimal conditions of lignin degradation were obtained by response surface experiment: 4% glucose oxidase, 0.74% malonic acid and 3.29% CaCl₂ were added for synergistic degradation at 37 ℃ with 50% of water content. After 72 h quickly enzymatic hydrolysis, the degradation rate of lignin was 45.84%.

CONCLUSIONS

A new green and efficient method for lignin removal from straw was obtained, which provided a reference for the efficient utilization of straw and lignin peroxidase.

Understanding Online Registry Facilitators and Barriers Experienced by Black Brain Health Registry Participants: The Community Engaged Digital Alzheimer's Research (CEDAR) Study

BACKGROUND

Failure of Alzheimer's disease and related diseases (ADRD) research studies to include and engage Black participants is a major issue, which limits the impact and generalizability of research findings. Little is known about participation of Black adults in online ADRD-related research registries.

OBJECTIVES

As part of the Community Engaged Digital Alzheimer's Research (CEDAR) Study, this study aims to increase our understanding of facilitators and barriers of Black adults to participating in ADRD-related online registries, as well as to understand their preferences for communication channels.

DESIGN, SETTING, PARTICIPANTS, MEASUREMENTS

We invited all Black participants enrolled in the Brain Health Registry (BHR) to complete a cross-sectional online survey. The survey consisted of rating scales and open-text questions asking about their attitudes towards brain health research, reasons for joining and continuing to participate in BHR, difficulties with participating, and preferences for modes of contact and website usage.

RESULTS

Of all invited Black BHR participants (N=3,636), 198 (5.5%) completed the survey. The mean age was 58.4 (SD=11.3), mean years of education were 16.3 (SD=2.4), and 85.5% identified as female. Reported facilitators for joining and continuing to participate in BHR were personal interest (e.g., learning more about own brain health) and altruism (e.g., helping research). Among additional registry features which could encourage return, receiving feedback or scores about BHR tasks was rated the highest. Of those who found BHR participation difficult (21%), the most frequent reason was time burden. The most preferred way of receiving study information was via email. Participants reported that the websites that they used the most were YouTube and Facebook.

DISCUSSION

The results of our study can inform the development of culturally-responsive registry features and engagement efforts to improve inclusion and participation of Black adults in online ADRD research. Providing participants with feedback about their registry performance and reducing the number of registry tasks are among the recommended strategies.

The Community Engaged Digital Alzheimer's Research (CEDAR) Study: A Digital Intervention to Increase Research Participation of Black American Participants in the Brain Health Registry

BACKGROUND

Although Black/African American older adults bear significant inequities in prevalence, incidence, and outcomes of Alzheimer's disease and related dementias, they are profoundly under-included in Alzheimer's Disease research. Community-Engaged Research (e.g., equitable community/science partnerships) is an evidence-based approach for improving engagement of underrepresented populations into Alzheimer's Disease research, but has lacked scalability to the national level. As internet use among older adults from underrepresented populations continues to grow, internet-based research shows promise as a feasible, valid approach to engagement and longitudinal assessment. The Community Engaged Digital Alzheimer's Research (CEDAR) study utilizes a community-engaged research approach to increase the engagement and research participation of Black/African American adults in the Brain Health Registry (BHR) and Alzheimer Disease clinical research.

OBJECTIVES

To describe the methods and evaluate the feasibility of the CEDAR culturally-informed digital platform within BHR.

DESIGN

All Black/African American participants in BHR were invited to enroll in CEDAR and to consider serving on a newly convened Community-Scientific Partnership Board to guide the study. The community board guided the development a culturally-informed cadre of engagement materials and strategies to increase research participation. Engagement strategies included incentives for study task completion, culturally-informed communications (e.g., landing page, emails and social media), resources about brain health, and video and written testimonials by CEDAR participants.

SETTING

BHR, an Internet-based registry and cohort.

PARTICIPANTS

BHR participants self-identifying as Black/African American were invited to enroll. All participants who signed an online informed consent document were enrolled.

MEASUREMENTS

We report the number of participants invited, enrolled, completed tasks, and volunteered to join the community board. We compared the demographics, cognitive profile, and baseline BHR task completion rates between CEDAR participants and all those invited to join the study.

RESULTS

Of 3738 invited, 349 (9.34%) enrolled in CEDAR. 134 (37% of CEDAR participants) volunteered to join the community board, of which 19 were selected for the community board. Compared to those invited, the CEDAR cohort had a higher percentage of female participants (84.5%) and a lower percentage of participants who identify as belonging to more than one ethnocultural group (21.8%). Compared to those did not enroll in CEDAR, those enrolled in CEDAR had a higher percentage of participants completing all BHR tasks (22%) and a higher percentage of participants completing at least one cognitive test (76%). Those enrolled in CEDAR also had a higher percentage of participants having an enrolled study partner (18%).

CONCLUSIONS

A culturally-informed Community-Engaged Research approach, including a remotely-convened community board, to engagement of Black/African American participants in an online research registry is feasible. This approach can be adapted for use in various clinical studies and other settings. Future studies will evaluate the effectiveness of the engagement strategies.

Genomic insights into the metabolic potential of a novel lignin-degrading and polyhydroxyalkanoates producing bacterium Pseudomonas sp. Hu109A

Lignin is the most abundant heterogeneous aromatic polymer present on planet Earth and is recalcitrant to degradation due to its complex structure, therefore, imposing a challenge to biorefinery procedures. Identifying new microbial strains with the potential to valorize lignin into useful compounds is indispensable to achieving green sustainable consumption. In this study, a novel Pseudomonas strain designated as Hu109A was isolated from the termite gut and the genome was sequenced and analyzed further. The genome contains a circular chromosome with the size of 5,131,917 bp having a GC content of 62.6% and 4698 genes. Genome annotation reveals that the strain possesses lignin-oxidizing enzymes such as DyP-type peroxidases, laccase, dioxygenase, and aromatic degradation gene clusters. The genome also contains O-methyltransferases which function in accelerating the lignin degradation by methylating the free hydroxyl phenolic compounds which in high concentration can inhibit the lignin peroxidase. Furthermore, the genome exhibits two gene clusters encoding the enzymes related to polyhydroxyalkanoates (PHA) synthesis. Pseudomonas strains are generally assumed to produce medium chain length PHAs (mcl-PHAs) only, however, strain Hu109A contains both Class II PHA synthase genes involved in mcl-PHAs and Class III PHA synthase gene involved in short-chain length PHAs (scl-PHAs). Gas Chromatography-Mass Spectrometry (GC-MS) analysis showed that using 1 g/L lignin as the sole carbon source, the maximum production of PHA observed was 103.68 mg/L, which increased to 186 mg/L with an increase in lignin concentration to 3 g/L. However, PHA production while using glucose as the sole carbon source was significantly lower than the lignin source, and maximum production was 125.6 mg/L with 3 g/L glucose. The strain Hu109A can tolerate a broad range of solvents including methanol, isopropanol, dimethylformamide, and ethanol, revealing its potential for industrial applications.