Psychrophilic Extremophiles from Antarctica: Biodiversity and Biotechnological Potential

Bowman John P.,Abell Gyu C.J.,Nichols Carol A. Mancuso Korea Institute of Ocean ScienceTechnology 2005 Ocean and Polar Research Vol.27 No.2

Recently there has been a rapid accumulation of knowledge of microbial life in cold and frozen ecosystems. This understanding has revealed the extensive diversity of psychrophilic prokaryotes. Cultivation-based and molecular-based surveys have been performed in Antarctic habitats ranging from glacial ice to continental shelf sediments. Results indicate that psychrophilic taxa permeate throughout the Bacteria while they represent a more mysterious element of diversity in the Archaea owing to a notable lack of cultured strains. In certain cold climate ecosystems the diversity of psychrophilic populations reach levels comparable to the richest temperate equivalents. Within these communities must exist tremendous genetic diversify that is potentially of fundamental and of practical value. So far this genetic pool has been hardly explored. Only recently have genomic data become available for various psychrophilic prokaryotes and more is required. This owes to the fact that psychrophilic microbes possess manifold mechanisms for cold adaptations, which not only Provide enhanced survival and Persistence but Probably also contributes to niche specialisation. These mechanisms, including cold-active and ice-active proteins, polyunsaturated lipids and exopolysaccharides also have a great interest to biotechnologists.

An advanced glycation end product (AGE)-receptor for AGEs (RAGE) axis restores adipogenic potential of senescent preadipocytes through modulation of p53 protein function.

Chen, Chih-Yu,Abell, Allison Martorano,Moon, Yang Soo,Kim, Kee-Hong American Society for Biochemistry and Molecular Bi 2013 The Journal of biological chemistry Vol.288 No.15

Gastroparesis Updates on Pathogenesis and Management

( Nanlong Liu ),( Thomas Abell ) 대한간학회 2017 Gut and Liver Vol.11 No.5

Gastroparesis (Gp) is a chronic disease that presents with clinical symptoms of early satiety, bloating, nausea, vomit-ing, and abdominal pain. Along with these symptoms, an objective finding of delayed gastric emptying, along with a documented absence of gastric outlet obstruction, are re-quired for diagnosis. This article focuses on updates in the pathogenesis and management of Gp. Recent studies on full thickness biopsies of Gp patients have shed light on the complex interactions of the central, autonomic, and enteric nervous systems, which all play key roles in maintaining nor-mal gut motility. The management of Gp has evolved beyond prokinetics and antiemetics with the use of gastric electrical stimulators (GES). In addition, this review aims to introduce the concept of gastroparesis-like syndrome (GLS). GLS helps groups of patients who have the cardinal symptoms of Gp but have a normal or rapid emptying test. Recent tests have shown that patients with Gp and GLS have similar pathophys-iology, benefit greatly from GES placement, and likely should be treated in a similar manner. (Gut Liver 2017;11:579-589)

Metagenomic Analysis of the Viral Communities in Fermented Foods

Park, Eun-Jin,Kim, Kyoung-Ho,Abell, Guy C. J.,Kim, Min-Soo,Roh, Seong Woon,Bae, Jin-Woo American Society for Microbiology 2011 Applied and environmental microbiology Vol.77 No.4

<B>ABSTRACT</B><P>Viruses are recognized as the most abundant biological components on Earth, and they regulate the structure of microbial communities in many environments. In soil and marine environments, microorganism-infecting phages are the most common type of virus. Although several types of bacteriophage have been isolated from fermented foods, little is known about the overall viral assemblages (viromes) of these environments. In this study, metagenomic analyses were performed on the uncultivated viral communities from three fermented foods, fermented shrimp, kimchi, and sauerkraut. Using a high-throughput pyrosequencing technique, a total of 81,831, 70,591 and 69,464 viral sequences were obtained from fermented shrimp, kimchi and sauerkraut, respectively. Moreover, 37 to 50% of these sequences showed no significant hit against sequences in public databases. There were some discrepancies between the prediction of bacteriophages hosts via homology comparison and bacterial distribution, as determined from 16S rRNA gene sequencing. These discrepancies likely reflect the fact that the viral genomes of fermented foods are poorly represented in public databases. Double-stranded DNA viral communities were amplified from fermented foods by using a linker-amplified shotgun library. These communities were dominated by bacteriophages belonging to the viral order<I>Caudovirales</I>(i.e.,<I>Myoviridae</I>,<I>Podoviridae</I>, and<I>Siphoviridae</I>). This study indicates that fermented foods contain less complex viral communities than many other environmental habitats, such as seawater, human feces, marine sediment, and soil.</P>

Psychrophilic Extremophiles from Antarctica: Biodiversity and Biotechnological Potential

John P. Bowman,Guy C.J. Abell,Carol A. Mancuso Nichols 한국해양과학기술원 2005 Ocean and Polar Research Vol.27 No.2

Recently there has been a rapid accumulation of knowledge of microbial life in cold and frozen ecosystems. This understanding has revealed the extensive diversity of psychrophilic prokaryotes. Cultivation-based and molecular-based surveys have been performed in Antarctic habitats ranging from glacial ice to continental shelf sediments. Results indicate that psychrophilic taxa permeate throughout the Bacteria while they represent a more mysterious element of diversity in the Archaea owing to a notable lack of cultured strains. In certain cold climate ecosystems the diversity of psychrophilic populations reach levels comparable to the richest temperate equivalents. Within these communities must exist tremendous genetic diversity that is potentially of fundamental and of practical value. So far this genetic pool has been hardly explored. Only recently have genomic data become available for various psychrophilic prokaryotes and more is required. This owes to the fact that psychrophilic microbes possess manifold mechanisms for cold adaptations, which not only provide enhanced survival and persistence but probably also contributes to niche specialisation. These mechanisms, including cold-active and ice-active proteins, polyunsaturated lipids and exopolysaccharides also have a great interest to biotechnologists.

THE RELATION OF DIETARY FORMULATION AND DIGESTA PROPERTIES ON THE ATLANTIC SALMON (Salmo salar L.) GASTROINTESTINAL MICROBIAL COMMUNITY

Kamarul Zaman Zarkasi,Richard S. Taylor,Guy C.J. Abell,Mark L. Tamplin,Brett Glencross,John P. Bowman 한국수산과학회 양식분과 2015 한국수산과학회 양식분과 학술대회 Vol.2015 No.5

High-resolution Mapping of Hyperglycemia-induced Gastric Slow Wave Dysrhythmias

Peng Du,Gregory O’Grady,Niranchan Paskaranandavadivel,Shou-jiang Tang,Thomas Abell,Leo K Cheng 대한소화기 기능성질환∙운동학회 2019 Journal of Neurogastroenterology and Motility (JNM Vol.25 No.2

Background/Aims It is now recognised that gastric dysrhythmias are best characterised by their spatial propagation pattern. Hyperglycemia is an important cause of gastric slow wave dysrhythmia, however, the spatiotemporal patterns of dysrhythmias in this context have not been investigated. This study aims to investigate the relationship between hyperglycemia and the patterns of dysrhythmias by employing high-resolution (multi-electrode) mapping simultaneously at the anterior and posterior gastric serosa. Methods High-resolution mapping (8 × 16 electrodes per serosal) was performed in 4 anesthetized hounds. Baseline recordings (21 ± 8 minutes) were followed by intravenous injection of glucagon (0.5 mg per dose) and further recordings (59 ± 15 minutes). Blood glucose levels were monitored manually using a glucose sensing kit at regular 5-minute intervals. Slow wave activation maps, amplitudes, velocity, anisotropic ratio, and frequency were calculated. Differences were compared between baseline and post glucagon injection. Results Baseline slow waves propagated symmetrically and antegrade. The blood glucose levels were increased by an average of 112% compared to the baseline by the end of the recordings. All subjects demonstrated elevated incidence of slow wave dysrhythmias following injection compared to the baseline (48 ± 23% vs 6 ± 4%, P < 0.05). Dysrhythmias arose simultaneously or independently on anterior and posterior serosa. Spatial dysrhythmias occurred before and persisted after the onset and disappearance of temporal dysrhythmias. Conclusions Infusion of glucagon induced gastric slow wave dysrhythmias, which occurred across a heterogeneous range of patterns and frequencies. The spatial dysrhythmias of gastric slow waves were shown to be more prevalent and persisted over a longer period of time compared to the temporal dysrhythmias.

Gastric Electrical Stimulation Is an Option for Patients with Refractory Cyclic Vomiting Syndrome

( Inderpreet Grover ),( Richard Kim ),( Danielle C Spree ),( Christopher J Lahr ),( Archana Kedar ),( Shivangi Kothari ),( David Fleisher ),( Thomas L Abell ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2016 Journal of Neurogastroenterology and Motility (JNM Vol.22 No.4

Background/Aims Cyclic vomiting syndrome (CVS) is a disabling migraine variant manifesting as severe episodes of nausea and vomiting and often refractory to many therapies. Gastric electrical stimulation (GES), which can reduce nausea and vomiting in gastroparesis, may provide symptomatic relief for drug-refractory CVS. This study assessed the utility GES in reducing the symptoms of CVS and improving the quality of life. Methods A one-year, non-randomized, clinical study was conducted. Eleven consecutive patients with drug refractory, cyclic vomiting syndrome based on Rome III criteria and North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN), underwent treatment with temporary GES (Temp GES) and permanent GES (Perm GES). Post-treatment follow up was done up to one year after permanent gastric electrical stimulation therapy. Results Total symptom score decreased by 68% and 40% after temporary and permanent GES therapies, respectively. Hospital admission events significantly decreased to 1.50 (± 1.00) events from 9.14 (± 7.21) annual admissions prior to treatment with permanent GES. Vomiting episodes fell by 83% post Temp GES and 69% after Perm GES treatments. Mucosal electrogram values also changed after temporary stimulation. Conclusions In a small group of drug-refractory CVS patients, treatments with temporary and permanent GES significantly reduced the severity of gastrointestinal symptoms and frequency of hospital admissions.

Temporary Endoscopic Stimulation in Gastroparesis-like Syndrome

( Sanjeev Singh ),( Jeff Mccrary ),( Archana Kedar ),( Stephen Weeks ),( Brian Beauerle ),( Andrew Weeks ),( Omer Endashaw ),( Chris Lahr ),( Warren Starkebaum ),( Thomas Abell ) 대한소화기기능성질환·운동학회 2015 Journal of Neurogastroenterology and Motility (JNM Vol.21 No.4

Background/Aims Gastroparesis-like syndrome (GLS) is defined as gastroparesis-like symptoms with normal gastric scintigraphy. While the efficacy of gastric electrical stimulation (GES) in gastroparesis is well known, the utility of GES in GLS is largely unknown. Our aim was to clarify the role of GES in GLS. We implanted consecutive patients with symptoms of gastroparesis with temporary gastric electrical stimulation and observed changes in gastric scintigraphy and total symptom score. Methods Five hundred and fifty-one patients suffering from symptoms of gastroparesis (nausea, vomiting, bloating/distension, anorexia/ early satiety, and abdominal pain) with negative endoscopy underwent gastric scintigraphy with analysis of 1) solid radionuclide gastric emptying at 1, 2, and 4 hours (% remaining); 2) area under the gastric emptying curve (AUC) at 1, 2, and 4hours; and 3) total gastric emptying test (GET) (the sum of 1, 2, and 4 hour values). Patients were stratified into: delayed gastric emptying, normal gastric emptying, and rapid gastric emptying (Appendix). Of the 551 patients in the larger cohort, 379 had implantation of temporary gastric electrical stimulation (tGES). Gastrointestinal symptoms and gastric emptying were com - pared pre and post tGES implantation. Results After tGES, 2 hour gastric retention decreased (P < 0.01) for the delayed patients, and increased (P < 0.001) for normal and rapid patients. These changes were accompanied by improvements (P < 0.001) in vomiting, nausea, and total symptom scores in all 3 subgroups. Conclusions Gastric electrical stimulation may be an effective therapy for treating the symptoms of gastroparesis with normal gastric emptying.Further exploration of endoscopic electrical stimulation as a treatment for gastroparesis-like symptoms with non-delayed gastric emptying is needed. (J Neurogastroenterol Motil 2015;21:520-527)

Elimination of MMC Differential Currents via a feedback LTI control system

Abel Ferreira,Rodrigo Teixeira-Pinto,Oriol Gomis-Bellmunt,Miquel Teixido 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The interesting features of the modular multilevel converter makes it the VSC solution of choice by the manufactures in the HVDC field. Far more complex than the older VSC solutions, the MMC generates less harmonics and losses. One of its drawbacks is that, internally, this topology creates a double line frequency current component which flows between phases. This work describes the origin of the double line frequency current and presents, step-by-step stationary reference frame circulating current suppress controller (S-CCSC) as a feedback linear time invariant (LTI) control to cancel out this source of additional losses. The proposed S-CCSC solution was compared to the previously proposed 2ω rotating reference frame CCSC (R-CCSC). Both solutions show very fast results, removing almost instantaneously the second harmonic current without leaving any evidence of them in steady state. Moreover, the LTI solution is demonstrated to demand 33% less computational time, which is a clear advantage from a practical application perspective.