Consolidated microbial production of four-, five-, and six-carbon organic acids from crop residues: Current status and perspectives.

The production of platform organic acids has been heavily dependent on petroleum-based industries. However, petrochemical-based industries that cannot guarantee a virtuous cycle of carbons released during various processes are now facing obsolescence because of the depletion of finite fossil fuel reserves and associated environmental pollutions. Thus, the transition into a circular economy in terms of the carbon footprint has been evaluated with the development of efficient microbial cell factories using renewable feedstocks. Herein, the recent progress on bio-based production of organic acids with four-, five-, and six-carbon backbones, including butyric acid and 3-hydroxybutyric acid (C4), 5-aminolevulinic acid and citramalic acid (C5), and hexanoic acid (C6), is discussed. Then, the current research on the production of C4-C6 organic acids is illustrated to suggest future directions for developing crop-residue based consolidated bioprocessing of C4-C6 organic acids using host strains with tailor-made capabilities.

Recent advances in the microbial production of C4 alcohols by metabolically engineered microorganisms.

BACKGROUND: The heavy global dependence on petroleum-based industries has led to serious environmental problems, including climate change and global warming. As a result, there have been calls for a paradigm shift towards the use of biorefineries, which employ natural and engineered microorganisms that can utilize various carbon sources from renewable resources as host strains for the carbon-neutral production of target products. PURPOSE AND SCOPE: C4 alcohols are versatile chemicals that can be used directly as biofuels and bulk chemicals and in the production of value-added materials such as plastics, cosmetics, and pharmaceuticals. C4 alcohols can be effectively produced by microorganisms using DCEO biotechnology (tools to design, construct, evaluate, and optimize) and metabolic engineering strategies. SUMMARY OF NEW SYNTHESIS AND CONCLUSIONS: In this review, we summarize the production strategies and various synthetic tools available for the production of C4 alcohols and discuss the potential development of microbial cell factories, including the optimization of fermentation processes, that offer cost competitiveness and potential industrial commercialization.

A shortcut to carbon-neutral bioplastic production: Recent advances in microbial production of polyhydroxyalkanoates from C1 resources.

Since the 20th century, plastics that are widely being used in general life and industries are causing enormous plastic waste problems since improperly discarded plastics barely degrade and decompose. Thus, the demand for polyhydroxyalkanoates (PHAs), biodegradable polymers with material properties similar to conventional petroleum-based plastics, has been increased so far. The microbial production of PHAs is an environment-friendly solution for the current plastic crisis, however, the carbon sources for the microbial PHA production is a crucial factor to be considered in terms of carbon-neutrality. One­carbon (C1) resources, such as methane, carbon monoxide, and carbon dioxide, are greenhouse gases and are abundantly found in nature and industry. C1 resources as the carbon sources for PHA production have a completely closed carbon loop with much advances; i) fast carbon circulation with direct bioconversion process and ii) simple fermentation procedure without sterilization as non-preferable nutrients. This review discusses the biosynthesis of PHAs based on C1 resource utilization by wild-type and metabolically engineered microbial host strains via biorefinery processes.

Chemoautotroph Cupriavidus necator as a potential game-changer for global warming and plastic waste problem: A review.

Cupriavidus necator, a versatile microorganism found in both soil and water, can have both heterotrophic and lithoautotrophic metabolisms depending on environmental conditions. C. necator has been extensively examined for producing Polyhydroxyalkanoates (PHAs), the promising polyester alternatives to petroleum-based synthetic polymers because it has a superior ability for accumulating a considerable amount of PHAs from renewable resources. The development of metabolically engineered C. necator strains has led to their application for synthesizing biopolymers, biofuels and biochemicals such as ethanol, isobutanol and higher alcohols. Bio-based processes of recombinant C. necator have made much progress in production of these high-value products from biomass wastes, plastic wastes and even waste gases. In this review, we discuss the potential of C. necator as promising platform host strains that provide a great opportunity for developing a waste-based circular bioeconomy.

Rapid analysis of polyhydroxyalkanoate contents and its monomer compositions by pyrolysis-gas chromatography combined with mass spectrometry (Py-GC/MS).

Here, we report an analysis method for determining PHA (polyhydroxyalkanoates) contents and their monomer composition in microbial cells based on pyrolysis gas chromatography combined with mass spectrometry (Py-GC/MS). Various kinds of microbial cells accumulating different PHA contents and monomer compositions were prepared through the cultivation of Ralstonia eutropha and recombinant Escherichia coli. Py-GC/MS could analyse these samples in a short time without complicated pretreatment steps. Characteristic peaks such as 2-butenoic acid, 2-pentenoic acid, and hexadecanoic acid regarding PHA compositions and cell components were identified. Considering constituents of cells and ratios of peak areas of dehydrated monomers to hexadecanoic acid, a simple equation for estimation of PHA contents in microbial cells was derived. Also, monomer compositions of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) in R. eutropha could be successfully determined based on peak area of 2-butenoic acid and 2-pentenoic acid of Py-GC/MS, which are the corresponding species of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) in PHBV. Correlation of results between GC-FID and Py-GC/MS could be fitted very well. This method shows similar results for the samples obtained from same experimental conditions, allowing rapid and reliable analysis. Py-GC/MS can be a promising tool to rapidly screen PHA-positive strains based on polymer contents along with monomer compositions.

Uncinate Process Area as a New Sensitive Morphological Parameter to Predict Cervical Neural Foraminal Stenosis.

BACKGROUND: Hypertrophy of the uncovertebral joint has been considered as a major cause of cervical neural foraminal stenosis (CNFS). The cross-sectional area of the uncinate process is a key morphologic parameter in the identification of uncovertebral joint hypertrophy. To evaluate the connection between CNFS and the uncinate process, we devised a new morphological parameter, the uncinate process area (UPA). OBJECTIVE: We hypothesized that the UPA is an important morphologic parameter in the diagnosis of CNFS. STUDY DESIGN: Retrospective observational study. SETTING: The single center study in Incheon, Republic of Korea. METHODS: UPA data were collected from 146 patients with CNFS and 197 control subjects who underwent neck computed tomography (CT) as part of a routine medical examination. Neck CT images were obtained from all subjects. The whole cross-sectional area of the bone margin of the uncinate process was measured at the C5-6 intervertebral disc level on CT scans using a picture archiving and communications system. RESULTS: The average UPA was 15.52 mm-squared in the control group and 29.97 mm-squared in the CNFS group. The CNFS group displayed significantly greater UPA levels (P < 0.001). Regarding the validity of the UPA as a predictor of CNFS, the receiver operating characteristic curve analysis revealed an optimal cut-off point for the UPA of 21.15 mm-squared, with 91.8% sensitivity, 93.4% specificity, and an area under the curve of 0.972 (95% CI,0.956-0.989) in the CNFS group. LIMITATIONS: Anatomically, the UP is located on the superior lateral surfaces of the C3-7 cervical vertebral bodies. However, we focused on the C5-6 uncovertebral joint level, because many previous studies revealed C6 UP has the greatest height among UP and C5-6 uncovertebral joint hypertrophy is a primary cause of CNFS. CONCLUSIONS: The newly devised UPA is a sensitive parameter for assessing CNFS. A hypertrophied UPA is associated with an increased risk of CNFS. We think that this result will be helpful for diagnostic radiology in evaluating patients with CNFS.Institutional Review Board (IRB) approval number: IS16RISI0002KEY WORDS: Uncinate process area, cervical neural foraminal stenosis, Uncovertebral joint hypertrophy, optimal cut-off point, cross- sectional area.

The Role of the Ligamentum Flavum Area as a Morphological Parameter of Lumbar Central Spinal Stenosis.

BACKGROUND: Hypertrophy of the ligamentum flavum (LF) has been considered as a major cause of lumbar central spinal stenosis (LCSS). Previous studies have found that ligamentum flavum thickness (LFT) is correlated with aging, disc degeneration, and lumbar spinal stenosis. However, hypertrophy is different from thickness. Thus, to evaluate hypertrophy of the whole LF, we devised a new morphological parameter, called the ligamentum flavum area (LFA). OBJECTIVES: We hypothesized that the LFA is a key morphologic parameter in the diagnosis of LCSS. STUDY DESIGN: Retrospective observational study. SETTING: The single center study in Seoul, Republic of Korea. METHODS: LF samples were collected from 166 patients with LCSS, and from 167 controls who underwent lumbar magnetic resonance imaging (MRI) as part of a routine medical examination. T1-weighted axial MR imageswere acquired at the facet joint level from individual patients. We measured the LFA and LFT at the L4-L5 intervertebral level on MRI using a picture archiving and communications system. The LFA was measured as the cross-sectional area of the whole LF at the L4-L5 stenotic level. The LFT was measured by drawing a line along the side of the ligament facing the spinal canal and along the laminar side of the ligament curve and then measuring the thickest point at the L4-L5 level. RESULTS: The average LFA was 96.56 ± 30.74 mm2 in the control group and 132.69 ± 32.68 mm2 in the LCSS group. The average LFT was 3.61 ± 0.72 mm in the control group and 4.24 ± 0.97 mm in the LCSS group. LCSS patients had significantly higher LFA (P < 0.001) and LFT (P < 0.001). Regarding the validity of both LFA and LFT as predictors of LCSS, Receiver Operator Characteristics (ROC) curve analysis showed that the best cut-off point for the LFA was 105.90 mm2, with 80.1% sensitivity, 76.0% specificity, and area under the curve (AUC) of 0.83 (95% CI, 0.78 - 0.87). The best cut off-point of the LFT was 3.74 mm, with 70.5% sensitivity, 66.5% specificity, and AUC of 0.72 (95% CI, 0.66 - 0.77). LIMITATIONS: The principal methodological limitation was the retrospective observational nature. Anatomically, degenerative lumbar spinal stenosis can involve the central canal, foramina, and lateral recess. However, we focused on LCSS only. CONCLUSIONS: Although the LFT and LFA were both significantly associated with LCSS, the LFA was a more sensitive measurement parameter. Thus, to evaluate LCSS patients, the treating doctor should more carefully analyze the LFA than LFT.Institutional Review Board (IRB) approval number: S2015-1328-0001Key words: Ligamentum flavum, ligamentum flavum area, ligamentum flavum thickness, lumbar central spinal stenosis, hypertrophy of the ligamentum flavum, morphological parameter, cross-sectional area, optimal cut-off point.

The effect of polydeoxyribonucleotide prolotherapy on posterior tibial tendon dysfunction after ankle syndesmotic surgery: A case report.

RATIONALE: Ankle syndesmotic injuries occasionally require long-term therapy for recovery and can result in tendon injury. Posterior tibial tendon dysfunction (PTTD) is an acquired deformity that can cause flatfoot deformity. The current nonoperative management of PTTD includes nonsteroidal antiinflammatory drugs (NSAIDs), orthopedic devices. Although various treatment options have been attempted, optimal treatments for each stage of the condition are debated. Polydeoxyribonucleotide (PDRN) is effective in healing of chronic wounds associated with tissue damage by attracting tissue growth factors. PATIENT CONCERNS: A 67-year-old woman who presented at our pain clinic with pain on the inside of ankle. She had a syndesmotic screw fixation 3 years prior. Her ankle pain had persisted after the removal of screws and edema for about 1 month resulting from long-term NSAIDs administration. DIAGNOSES: The origin of the pain was possibly tibialis posterior muscle and posterior tibial tendon and she was diagnosed as PTTD after syndesmosis surgery. INTERVENTIONS: Sono guided prolotherapy with PDRN was carried out. OUTCOMES: Patient showed improvement in the arch of the foot, experienced pain relief, and was able to wear regular shoes without any orthopedic device. LESSONS: This case report highlights that PDRN prolotherapy is a safe and efficient therapeutic option for the treatment of PTTD.

Thalamic Pain Misdiagnosed as Cervical Disc Herniation.

Thalamic pain is a primary cause of central post-stroke pain (CPSP). Clinical symptoms vary depending on the location of the infarction and frequently accompany several pain symptoms. Therefore, correct diagnosis and proper examination are not easy. We report a case of CPSP due to a left acute thalamic infarction with central disc protrusion at C5-6. A 45-year-old-male patient experiencing a tingling sensation in his right arm was referred to our pain clinic under the diagnosis of cervical disc herniation. This patient also complained of right cramp-like abdominal pain. After further evaluations, he was diagnosed with an acute thalamic infarction. Therefore detailed history taking should be performed and examiners should always be aware of other symptoms that could suggest a more dangerous disease.

[Educational issues and strategies to improve APN education].

PURPOSE: This study was aimed at exploring the current status of graduate programs for an advanced practice nurse(APN) to recommend future directions of APN education. METHODS: A total of 142 students enrolled in seven APN specialty programs, 67 professors who were involved in APN education, and nine nurse administrators participated in the study. Data was collected by questionnaires and focus group interviews. RESULTS: The current definition of APN was found not to be specific enough to represent expected roles of APN in regards to knowledge, attitudes, roles, and skills. Standard curricula employed regardless of the area of APN specialty, lack of qualified clinical practice settings, as well as prepared instructors were found to be problematic. CONCLUSION: The following needs to be addressed: 1. redefining of APN roles, 2. tailoring specialty areas of APN, 3. consolidating educational programs, and 4. ensuring APN role models and faculty. Suggesting a CNS role in Korean APN, areas of APN should be rearranged to clarify their roles and educational programs need to be further developed to meet the expectations and quality of APNs. It is necessary to ensure APN's employment in the health care system by laws and policies to perform advanced nursing roles.