Determining individual suitability for neoadjuvant systemic therapy in breast cancer patients through deep learning.

BACKGROUND: The survival advantage of neoadjuvant systemic therapy (NST) for breast cancer patients remains controversial, especially when considering the heterogeneous characteristics of individual patients. OBJECTIVE: To discern the variability in responses to breast cancer treatment at the individual level and propose personalized treatment recommendations utilizing deep learning (DL). METHODS: Six models were developed to offer individualized treatment suggestions. Outcomes for patients whose actual treatments aligned with model recommendations were compared to those whose did not. The influence of certain baseline features of patients on NST selection was visualized and quantified by multivariate logistic regression and Poisson regression analyses. RESULTS: Our study included 94,487 female breast cancer patients. The Balanced Individual Treatment Effect for Survival data (BITES) model outperformed other models in performance, showing a statistically significant protective effect with inverse probability treatment weighting (IPTW)-adjusted baseline features [IPTW-adjusted hazard ratio: 0.51, 95% confidence interval (CI), 0.41-0.64; IPTW-adjusted risk difference: 21.46, 95% CI 18.90-24.01; IPTW-adjusted difference in restricted mean survival time: 21.51, 95% CI 19.37-23.80]. Adherence to BITES recommendations is associated with reduced breast cancer mortality and fewer adverse effects. BITES suggests that patients with TNM stage IIB, IIIB, triple-negative subtype, a higher number of positive axillary lymph nodes, and larger tumors are most likely to benefit from NST. CONCLUSIONS: Our results demonstrated the potential of BITES to aid in clinical treatment decisions and offer quantitative treatment insights. In our further research, these models should be validated in clinical settings and additional patient features as well as outcome measures should be studied in depth.

Spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells maintain pluripotency of stem cells by regulating hypoxia-inducible factors.

BACKGROUND: Spontaneous spheroid culture is a novel three-dimensional (3D) culture strategy for the rapid and efficient selection of progenitor cells. The objectives of this study are to investigate the pluripotency and differentiation capability of spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells (AB-MSCs); compare the advantages of spontaneous spheroids to those of mechanical spheroids; and explore the mechanisms of stemness enhancement during spheroid formation from two-dimensional (2D) cultured cells. METHODS: AB-MSCs were isolated from the alveolar bones of C57BL/6 J mice. Spontaneous spheroids formed in low-adherence specific culture plates. The stemness, proliferation, and multi-differentiation capacities of spheroids and monolayer cultures were investigated by reverse transcription quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, alkaline phosphatase (ALP) activity, and oil-red O staining. The pluripotency difference between the spontaneous and mechanical spheroids was analyzed using RT-qPCR. Hypoxia-inducible factor (HIFs) inhibition experiments were performed to explore the mechanisms of stemness maintenance in AB-MSC spheroids. RESULTS: AB-MSCs successfully formed spontaneous spheroids after 24 h. AB-MSC spheroids were positive for MSC markers and pluripotency markers (Oct4, KLF4, Sox2, and cMyc). Spheroids showed higher Ki67 expression and lower Caspase3 expression at 24 h. Under the corresponding conditions, the spheroids were successfully differentiated into osteogenic and adipogenic lineages. AB-MSC spheroids can induce neural-like cells after neurogenic differentiation. Higher expression of osteogenic markers, adipogenic markers, and neurogenic markers (NF-M, NeuN, and GFAP) was found in spheroids than in the monolayer. Spontaneous spheroids exhibited higher stemness than mechanical spheroids did. HIF-1α and HIF-2α were remarkably upregulated in spheroids. After HIF-1/2α-specific inhibition, spheroid formation was significantly reduced. Moreover, the expression of the pluripotency genes was suppressed. CONCLUSIONS: Spontaneous spheroids from AB-MSCs enhance stemness and pluripotency. HIF-1/2α plays an important role in the stemness regulation of spheroids. AB-MSC spheroids exhibit excellent multi-differentiation capability, which may be a potent therapy for craniomaxillofacial tissue regeneration.

ENO1 promotes immunosuppression and tumor growth in pancreatic cancer.

BACKGROUND: Pancreatic adenocarcinoma (PAAD) is a highly aggressive and malignant cancer type with the highest mortality rate of all major cancers. However, the molecular and tumor immune escape mechanism underlying pancreatic cancer remains largely unclear. α-enolase (ENO1) is a glycolytic enzyme reported to overexpress in a variety of cancer types. This study was undertaken to investigate the functional role and therapeutic potential of ENO1 in pancreatic cancer. METHODS: We examined the expression levels of ENO1 across a broad spectrum of cancer types from the TCGA database. ENO1-knockout (ENO1-KO) through CRISPR/CAS9 technology in a mouse pancreatic cancer cell line (PAN02) was used to analyze the role of ENO1 on proliferation and colony formation. Flow cytometry and RT-PCR were also applied to analyze T lymphocytes and relevant cytokines. RESULTS: In the present study, we identified that ENO1 promoted pancreatic cancer cell proliferation. Our bioinformatics data indicated that ENO1 was significantly overexpressed in pancreatic cancer cell lines and tissues. Survival analyses revealed that ENO1 overexpression implicated poor survival of PAAD patients. Knockout of ENO1 expression repressed the ability of proliferation and colony formation in PAN02. In addition, ENO1-KO significantly decreased tumor growth in mouse models. Further flow cytometry and RT-PCR analysis revealed that ENO1-KO modulates the tumor microenvironment (TME), especially in suppressed Treg cells and inducing anti-tumor cytokine responses. CONCLUSIONS: Taken together, our data showed that ENO1 was an oncogenic biomarker and might serve as a promising target for immunotherapy of pancreatic cancer.

Spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells maintain pluripotency of stem cells by regulating hypoxia-inducible factors

BACKGROUND: Spontaneous spheroid culture is a novel three-dimensional (3D) culture strategy for the rapid and efficient selection of progenitor cells. The objectives of this study are to investigate the pluripotency and differentiation capability of spontaneous spheroids from alveolar bone-derived mesenchymal stromal cells (AB-MSCs); compare the advantages of spontaneous spheroids to those of mechanical spheroids; and explore the mechanisms of stemness enhancement during spheroid formation from two-dimensional (2D) cultured cells. METHODS: AB-MSCs were isolated from the alveolar bones of C57BL/6 J mice. Spontaneous spheroids formed in low-adherence specific culture plates. The stemness, proliferation, and multi-differentiation capacities of spheroids and monolayer cultures were investigated by reverse transcription quantitative polymerase chain reaction (RT-qPCR), immunofluorescence, alkaline phosphatase (ALP) activity, and oil-red O staining. The pluripotency difference between the spontaneous and mechanical spheroids was analyzed using RT-qPCR. Hypoxia-inducible factor (HIFs) inhibition experiments were performed to explore the mechanisms of stemness maintenance in AB-MSC spheroids. RESULTS: AB-MSCs successfully formed spontaneous spheroids after 24 h. AB-MSC spheroids were positive for MSC markers and pluripotency markers (Oct4, KLF4, Sox2, and cMyc). Spheroids showed higher Ki67 expression and lower Caspase3 expression at 24 h. Under the corresponding conditions, the spheroids were successfully differentiated into osteogenic and adipogenic lineages. AB-MSC spheroids can induce neural-like cells after neurogenic differentiation. Higher expression of osteogenic markers, adipogenic markers, and neurogenic markers (NF-M, NeuN, and GFAP) was found in spheroids than in the monolayer. Spontaneous spheroids exhibited higher stemness than mechanical spheroids did. HIF-1α and HIF-2α were remarkably upregulated in spheroids. After HIF-1/2α-specific inhibition, spheroid formation was significantly reduced. Moreover, the expression of the pluripotency genes was suppressed. CONCLUSIONS: Spontaneous spheroids from AB-MSCs enhance stemness and pluripotency. HIF-1/2α plays an important role in the stemness regulation of spheroids. AB-MSC spheroids exhibit excellent multi-differentiation capability, which may be a potent therapy for craniomaxillofacial tissue regeneration.

Effects of basketball on the health of chinese people / Efeitos do basquete na saúde do povo chinês / Efectos del baloncesto en la salud del pueblo chino

ABSTRACT Objective: With the development of the economy, people's awareness of health care has been continuously improved. The concept of fitness has constantly been expanded by the population, propitiating the development of this industry. Methods: As an essential part of the development strategy of a modern and powerful country, the two national strategies of National Fitness and Healthy China provide guarantees to meet people's needs for a better life in the new era. Results: Basketball is rich in diversity; its intensity and load are also suitable for people of different ages. Therefore, basketball plays an active and effective role in realizing the national physical fitness program, improving the overall level of Chinese basketball, and improving the physical and mental health of the masses. Appropriate and reasonable exercise is the basis for ensuring physical health; thus, national physical fitness has become an essential prerequisite for national health, closely related and feasible to be integrated. Conclusions: Starting from the significance of the integration of physical fitness and national health, this paper analyzes the effects of basketball on people's health at different ages and presents corresponding guidance strategies. Level of evidence II; Therapeutic studies - investigation of treatment results.

RESUMO Objetivo: Com o desenvolvimento da economia, a conscientização das pessoas sobre os cuidados com a saúde tem sido continuamente melhorada. O conceito de fitness tem sido continuamente expandido pela população, propiciando o desenvolvimento dessa indústria. Métodos: Como parte importante da estratégia de desenvolvimento de um país moderno e poderoso, as duas estratégias nacionais da National Fitness e da Healthy China oferecem garantias para atender às necessidades das pessoas para uma vida melhor na nova era. Resultados: O basquetebol é rico em diversidade, sua intensidade e carga também são adequadas para pessoas de diferentes idades. Portanto, o basquetebol desempenha um papel ativo e eficaz na realização do programa nacional de aptidão física, melhorando o nível geral do basquetebol chinês e melhorando a saúde física e mental das massas. Exercício apropriado e razoável é a base para assegurar a saúde física, assim a aptidão física nacional se tornou um importante pré-requisito para a saúde nacional, que está intimamente relacionada e é viável de ser integrada. Conclusões: Partindo do significado da integração da aptidão física e saúde nacional, este documento analisa os efeitos do basquetebol na saúde das pessoas em diferentes idades, e apresenta estratégias de orientação correspondentes. Nível de evidência II; Estudos terapêuticos - investigação de resultados de tratamento.

RESUMEN Objetivo: Con el desarrollo de la economía, la conciencia de la gente sobre los cuidados con la salud ha sido continuamente mejorada. El concepto de fitness ha sido ampliado continuamente por la población, propiciando el desarrollo de esta industria. Métodos: Como parte importante de la estrategia de desarrollo de un país moderno y poderoso, las dos estrategias nacionales de Acondicionamiento Físico Nacional y China Saludable ofrecen garantías para satisfacer las necesidades de la gente para una vida mejor en la nueva era. Resultados: El baloncesto es rico en diversidad, su intensidad y carga también son adecuadas para personas de diferentes edades. Por lo tanto, el baloncesto desempeña un papel activo y eficaz en la realización del programa nacional de acondicionamiento físico, en la mejora del nivel general del baloncesto chino y en la mejora de la salud física y mental de las masas. El ejercicio adecuado y razonable es la base para garantizar la salud física, por lo que la aptitud física nacional se ha convertido en un importante prerrequisito para la salud nacional, que está estrechamente relacionada y es factible de ser integrada. Conclusiones: Partiendo de la importancia de la integración de la aptitud física y la salud nacional, este documento analiza los efectos del baloncesto en la salud de las personas a diferentes edades y presenta las correspondientes estrategias de orientación.Nivel de evidencia II; Estudios terapéuticos - investigación de resultados de tratamiento.

Micro ribonucleic acid-448 regulates zinc finger e-box binding homeobox 1 to inhibit the growth of breast cancer cells and increase their sensitivity to chemotherapy.

OBJECTIVE: This study aimed to investigate the effect of Zinc Finger E-box Binding Homeobox 1 (ZEB1) regulation by Micro Ribonucleic acid (miR)-448 on Breast Cancer (BC) cells and their sensitivity to chemotherapy. METHODS: miR-448 and ZEB1 mRNA levels in BC and normal tissues were detected by qPCR, and ZEB1 protein was detected by Western Blotting (WB). The correlation between miR-448 and tumor metastasis, clinical staging, and ZEB1 expression was analyzed. MCF-7 cells were transfected or co-transfected with the miR-448 mimic, oe-ZEB1, or their negative controls. Changes in miR-448 and ZEB1 expression were detected by qPCR and WB. Cell proliferation was determined by CCK-8 assays, invasion changes were analyzed by Transwell assays, and apoptosis was detected by flow cytometry. RESULTS: miR-448 expression in BC tissues was lower than that in normal tissues, while ZEB1 expression was increased in the former. ZEB1 expression was lower in BC patients with lymph node metastasis than in those without. In patients with clinical stage I-III BC, miR-448 expression decreased with an increase in tumor stage, which was negatively correlated with ZEB1 expression. Upregulation of miR-448 expression can suppress MCF-7 cell proliferation and invasion and promote apoptosis. Upregulation of ZEB1 expression in cells overexpressing miR-448 can partially reverse the inhibition of BC cell growth induced by miR-448. miR-448 can enhance the sensitivity of cells toward paclitaxel and 5-fluorouracil. CONCLUSIONS: miR-448 suppresses cell proliferation and invasion and promotes apoptosis by targeting ZEB1. Moreover, it can increase the sensitivity of cells toward paclitaxel and 5-fluorouracil.

Micro ribonucleic acid-448 regulates zinc finger e-box binding homeobox 1 to inhibit the growth of breast cancer cells and increase their sensitivity to chemotherapy

Abstract Objective: This study aimed to investigate the effect of Zinc Finger E-box Binding Homeobox 1 (ZEB1) regulation by Micro Ribonucleic acid (miR)-448 on Breast Cancer (BC) cells and their sensitivity to chemotherapy. Methods: miR-448 and ZEB1 mRNA levels in BC and normal tissues were detected by qPCR, and ZEB1 protein was detected by Western Blotting (WB). The correlation between miR-448 and tumor metastasis, clinical staging, and ZEB1 expression was analyzed. MCF-7 cells were transfected or co-transfected with the miR-448 mimic, oe-ZEB1, or their negative controls. Changes in miR-448 and ZEB1 expression were detected by qPCR and WB. Cell proliferation was determined by CCK-8 assays, invasion changes were analyzed by Transwell assays, and apoptosis was detected by flow cytometry. Results: miR-448 expression in BC tissues was lower than that in normal tissues, while ZEB1 expression was increased in the former. ZEB1 expression was lower in BC patients with lymph node metastasis than in those without. In patients with clinical stage I-III BC, miR-448 expression decreased with an increase in tumor stage, which was negatively correlated with ZEB1 expression. Upregulation of miR-448 expression can suppress MCF-7 cell proliferation and invasion and promote apoptosis. Upregulation of ZEB1 expression in cells overexpressing miR-448 can partially reverse the inhibition of BC cell growth induced by miR-448. miR-448 can enhance the sensitivity of cells toward paclitaxel and 5-fluorouracil. Conclusions: miR-448 suppresses cell proliferation and invasion and promotes apoptosis by targeting ZEB1. Moreover, it can increase the sensitivity of cells toward paclitaxel and 5-fluorouracil.

Effects of CO2 pretreatment on the volatile compounds of dried Chinese jujube (Zizyphus jujuba Miller)

Abstract The aim of this study was to investigate whether anaerobic metabolites could induce volatile compounds and improve aroma of dried jujube (Ziziphus jujuba Miller). Jujube fruits were incubated in a polyvinyl chloride bag containing 5% CO2 and 95% N2 for up to 168 h at 25 °C and 3 samples were randomly removed every 6 h and oven dried to a moisture content of ≅ 20%. The volatile compounds of control and 5% CO2-pretreated Chinese jujube fruits were extracted by simultaneous distillation extraction and identified by gas chromatography-mass spectrometry(GC-MS). The acetaldehyde and ethanol contents were determined by gas chromatography (GC). The results indicated that a large accumulation of acetaldehyde and ethanol caused changes in aroma composition of dried jujube products and 5% CO2 pretreatment led to an increase in the levels of some compounds, particularly esters, acetaldehydes, and ethanol, whereas the amount of acids were decreased significantly. Principal component analysis showed that integrative scores of 5% CO2 pretreatment at 120 h were the highest, and aroma quality was better than that of the control. Relatively low concentrations of anaerobic respiration metabolites are good for jujube fruit aroma composition.

Note: A simple multi-channel optical system for modulation spectroscopies.

Photoreflectance-difference (PR/PRD) and reflectance-difference (RD) spectroscopies employ synchronic detection usually with lock-in amplifiers operating at moderate (200-1000 Hz) and high (50-100 KHz) modulation frequencies, respectively. Here, we report a measurement system for these spectroscopies based on a multichannel CCD spectrometer without a lock-in amplifier. In the proposed scheme, a typical PRD or RD spectrum consists of numerical subtractions between a thousand CCD captures recorded, while a photoelastic modulator is either operating or inhibited. This is advantageous and fits the slow response of CCD detectors to high modulation frequencies. The resulting spectra are processed with Savitzky-Golay filtering and compared well with those measured with conventional scanning systems based on lock-in amplifiers.

Production and characterization of algae extract from Chlamydomonas reinhardtii

Background: Algae offer many advantages as biofuel sources including: high growth rates, high lipid content, the ability to grow on non-agricultural land, and the genetic versatility to improve strains rapidly and produce co-products. Research is ongoing to make algae biofuels a more financially attractive energy option; however, it is becoming evident that the economic viability of algae-based fuels may hinge upon high-value co-products. This work evaluated the feasibility of using a co-product, algae extract, as a nutrient source in cell culture media. Results: Algae extract prepared from autolysed Chlamydomonas reinhardtii was found to contain 3.0% protein, 9.2% total carbohydrate, and 3.9% free α-amino acid which is similar to the nutrient content of commercially available yeast extract. The effects of algae extract on the growth and metabolism of laboratory strains of Escherichia coli and Saccharomyces cerevisiae were tested by substituting algae extract for yeast extract in LB and YPAD growth media recipes. Complex laboratory media supplemented with algae extract instead of yeast extract showed markedly improved effects on the growth and metabolism of common laboratory microorganisms in all cases except ethanol production rates in yeast. Conclusions: This study showed that algae extract derived from C. reinhardtii is similar, if not superior, to commercially available yeast extract in nutrient content and effects on the growth and metabolism of E. coli and S. cerevisiae. Bacto™ yeast extract is valued at USD $0.15-0.35 per gram, if algae extract was sold at similar prices, it would serve as a high-value co-product in algae-based fuel processes.

Gene expression profile analysis of human intervertebral disc degeneration.

In this study, we used microarray analysis to investigate the biogenesis and progression of intervertebral disc degeneration. The gene expression profiles of 37 disc tissue samples obtained from patients with herniated discs and degenerative disc disease collected by the National Cancer Institute Cooperative Tissue Network were analyzed. Differentially expressed genes between more and less degenerated discs were identified by significant analysis of microarray. A total of 555 genes were significantly overexpressed in more degenerated discs with a false discovery rate of < 3%. Functional annotation showed that these genes were significantly associated with membrane-bound vesicles, calcium ion binding and extracellular matrix. Protein-protein interaction analysis showed that these genes, including previously reported genes such as fibronectin, COL2A1 and ß-catenin, may play key roles in disc degeneration. Unsupervised clustering indicated that the widely used morphology-based Thompson grading system was only marginally associated with the molecular classification of intervertebral disc degeneration. These findings indicate that detailed, systematic gene analysis may be a useful way of studying the biology of intervertebral disc degeneration.

Desenho de placa em forma de borboleta para tratamento de fraturas do calcâneo / Design of butterfly-shaped plate and its application in treatment for calcaneal fractures

OBJETIVO: Apresentar um desenho de placa em forma de borboleta e sua aplicação no tratamento de fraturas do calcâneo e discutir suas indicações clínicas, vantagens e desvantagens. MÉTODOS: De fevereiro de 2008 a abril de 2010, 22 pacientes com 26 fraturas intra-articulares do calcâneo foram tratados com redução a céu aberto e fixação interna com placa em forma de borboleta. Dezesseis pacientes eram homens e 6 eram mulheres, com média de idade de 36,8 anos. Onze eram pés esquerdos e 15, direitos. De acordo com a classificação de Sanders, 12 eram fraturas de calcâneo Tipo II (inclusive 3 Tipo IIa, 7 Tipo IIb e 2 Tipo IIc) e 14 eram Tipo III (inclusive cinco do Tipo IIIab, 7 Tipo IIIac e duas do Tipo IIIbc). RESULTADOS: Dezessete pacientes (21 pés) foram submetidos a acompanhamento por em média 19,2 meses. Os desfechos funcionais foram avaliados com o sistema Maryland Foot Score. Entre os nove pés com fraturas Tipo II, sete receberam escore excelente e dois, bom. Entre as 12 fraturas Tipo III, seis tiveram escore excelente, cinco, bom e uma, razoável. CONCLUSÃO: A placa em forma de borboleta é aplicável ao tratamento de fraturas do calcâneo do Tipo II e Tipo III de Sanders, com a vantagem de garantir fixação confiável, facilitar a cirurgia, produzir menos complicações pós-operatórias e produzir melhores desfechos clínicos gerais. Nível de Evidência IV, Série de casos.

OBJECTIVE: To introduce the design of butterfly-shaped plate and its application in treatment for calcaneal fractures, and to discuss its clinical indications, advantages and disadvantages. METHODS: From February 2008 to April 2010, 22 patients with 26 intra-articular calcaneal fractures were treated by open reduction and internal fixation with butterfly-shape plate. Sixteen patients were male and 6 patients were female, with a mean age of 36.8 years. Eleven were left feet and 15, right. According to Sanders classification, 12 were Type II (including 3 Type IIa, 7 Type IIb and 2 Type IIc) and 14 were Type III (including 5 Type IIIab, 7 Type IIIac and 2 Type IIIbc). RESULTS: Seventeen patients (21 feet) were followed-up for an average of 19.2 months. The functional outcomes were assessed using the Maryland Foot Score system. Among the 9 feet with Type II fractures, 7 feet were scored excellent, 2 were good. Among the 12 Type III fractures, 6 were scored excellent, 5 were good, and one was fair. CONCLUSION: The butterfly-shaped plate is applicable to treatment for Sanders Type II and Type III calcaneal fractures, with advantages of ensuring reliable fixation, easier operation, fewer post-operative complications, and better clinical outcomes. Level of Evidence IV, Case Series.

Design of butterfly-shaped plate and its application in treatment for calcaneal fractures.

OBJECTIVE: To introduce the design of a butterfly-shaped plate and its application in the treatment of calcaneal fractures, and to discuss its clinical indications, advantages and disadvantages. METHODS: From February 2008 to April 2010, 22 patients with 26 intra-articular calcaneal fractures were treated by open reduction and internal fixation with a butterfly-shaped plate. Sixteen patients were male and six patients were female, with a mean age of 36.8 years. Eleven were left feet and 15, right. According to the Sanders classification, 12 were calcaneal fractures Type II (including three Type IIa, seven Type IIb and two Type IIc) and 14 were Type III (including five Type IIIab, seven Type IIIac and two Type IIIbc). RESULTS: Seventeen patients (21 feet) were followed-up for an average of 19.2 months. The functional outcomes were assessed using the Maryland Foot Score system. Among the nine feet with Type II fractures, seven feet were scored excellent, two were good. Among the 12 Type III fractures, six were scored excellent, five were good, and one was scored fair. CONCLUSION: The butterfly-shaped plate is applicable in the treatment of Sanders Type II and Type III calcaneal fractures, with the advantages of ensuring reliable fixation, facilitating the surgery, producing fewer postoperative complications, and generating better overall clinical outcomes. Level of Evidence IV, Case Series.

Co-metabolism of DDT by the newly isolated bacterium, pseudoxanthomonas sp. wax

Microbial degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) is the most promising way to clean up DDT residues found in the environment. In this paper, a bacterium designated as wax, which was capable of co-metabolizing DDT with other carbon sources, was isolated from a long-term DDT-contaminated soil sample by an enrichment culture technique. The new isolate was identified as a member of the Pseudoxanthomonas sp., based on its morphological, physiological and biochemical properties, as well as by 16S rRNA gene analysis. In the presence of 100 mg l-1 glucose, the wax strain could degrade over 95 percent of the total DDT, at a concentration of 20 mg l-1, in 72 hours, and could degrade over 60 percent of the total DDT, at a concentration of 100 mg l-1, in 144 hours. The wax strain had the highest degradation efficiency among all of the documented DDT-degrading bacteria. The wax strain could efficiently degrade DDT at temperatures ranging from 20 to 37ºC, and with initial pH values ranging from 7 to 9. The bacterium could also simultaneously co-metabolize 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), 2,2-bis(p-chlorophenyl)-1,1-dichlorethylene (DDE), and other organochlorine compounds. The wax strain could also completely remove 20 mg kg-1 of DDT from both sterile and non-sterile soils in 20 days. This study demonstrates the significant potential use of Pseudoxanthomonas sp. wax for the bioremediation of DDT in the environment.

Co-metabolism of DDT by the newly isolated bacterium, Pseudoxanthomonas sp. wax.

Microbial degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) is the most promising way to clean up DDT residues found in the environment. In this paper, a bacterium designated as wax, which was capable of co-metabolizing DDT with other carbon sources, was isolated from a long-term DDT-contaminated soil sample by an enrichment culture technique. The new isolate was identified as a member of the Pseudoxanthomonas sp., based on its morphological, physiological and biochemical properties, as well as by 16S rRNA gene analysis. In the presence of 100 mg l(-1) glucose, the wax strain could degrade over 95% of the total DDT, at a concentration of 20 mg l(-1), in 72 hours, and could degrade over 60% of the total DDT, at a concentration of 100 mg l(-1), in 144 hours. The wax strain had the highest degradation efficiency among all of the documented DDT-degrading bacteria. The wax strain could efficiently degrade DDT at temperatures ranging from 20 to 37°C, and with initial pH values ranging from 7 to 9. The bacterium could also simultaneously co-metabolize 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), 2,2-bis(p-chlorophenyl)-1,1-dichlorethylene (DDE), and other organochlorine compounds. The wax strain could also completely remove 20 mg kg(-1) of DDT from both sterile and non-sterile soils in 20 days. This study demonstrates the significant potential use of Pseudoxanthomonas sp. wax for the bioremediation of DDT in the environment.

Co-metabolism of DDT by the newly isolated bacterium, Pseudoxanthomonas sp. wax

Microbial degradation of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) is the most promising way to clean up DDT residues found in the environment. In this paper, a bacterium designated as wax, which was capable of co-metabolizing DDT with other carbon sources, was isolated from a long-term DDT-contaminated soil sample by an enrichment culture technique. The new isolate was identified as a member of the Pseudoxanthomonas sp., based on its morphological, physiological and biochemical properties, as well as by 16S rRNA gene analysis. In the presence of 100 mg l-1 glucose, the wax strain could degrade over 95% of the total DDT, at a concentration of 20 mg l-1, in 72 hours, and could degrade over 60% of the total DDT, at a concentration of 100 mg l-1, in 144 hours. The wax strain had the highest degradation efficiency among all of the documented DDT-degrading bacteria. The wax strain could efficiently degrade DDT at temperatures ranging from 20 to 37ºC, and with initial pH values ranging from 7 to 9. The bacterium could also simultaneously co-metabolize 1,1-dichloro-2,2-bis(p-chlorophenyl)ethane (DDD), 2,2-bis(p-chlorophenyl)-1,1-dichlorethylene (DDE), and other organochlorine compounds. The wax strain could also completely remove 20 mg kg-1 of DDT from both sterile and non-sterile soils in 20 days. This study demonstrates the significant potential use of Pseudoxanthomonas sp. wax for the bioremediation of DDT in the environment.