Astaxanthin Biosynthesis Enhanced by Reactive Oxygen Species in the Green Alga Haematococcus pluvialis

Kobayashi, Makio The Korean Society for Biotechnology and Bioengine 2003 Biotechnology and Bioprocess Engineering Vol.8 No.6

The unicellular green alga Haematococcus pluvialis has recently attracted great inter-est due to its large amounts of ketocarotenoid astaxanthin, 3,3'-dihydroxy-${\beta}$,${\beta}$-carotene-4,4'-dione, widely used commercially as a source of pigment for aquaculture. In the life cycle of H. pluvialis, astaxanthin biosynthesis is associated with a remarkable morphological change from green motile vegetative cells into red immotile cyst cells as the resting stage. In recent years we have studied this morphological process from two aspects: defining conditions governing astaxanthin biosynthesis and questioning the possible function of astaxanthin in protecting algal cells against environmental stress. Astaxanthin accumulation in cysts was induced by a variety of environmental conditions of oxidative stress caused by reactive oxygen species, intense light, drought, high salinity, and high temperature. In the adaptation to stress, abscisic acid induced by reactive oxygen species, would function as a hormone in algal morphogenesis from veget ative to cyst cells. Furthermore, measurements of both in vitro and in vivo antioxidative activities of astaxanthin clearly demonstrated that tolerance to excessive reactive oxygen species is greater in astaxanthin-rich cysts than in astaxanthin-poor cysts or astaxanthin-less vegetative cells. Therefore, reactive oxygen species are involved in the regulation of both algal morph O-genesis and carotenogenesis, and the accumulated astaxanthin in cysts can function as a protective agent against oxidative stress damage. In this study, the physiological roles of astaxanthin in stress response and cell protection are reviewed.

Functional research and development of soy sauce

Makio Kobayashi 한국생물공학회 2007 한국생물공학회 학술대회 Vol.2007 No.10

Astaxanthin Biosynthesis Enhanced by Reactive Oxygen Species in the Green Alga Haematococcus pluvialis

Makio Kobayashi 한국생물공학회 2003 Biotechnology and Bioprocess Engineering Vol.8 No.6

The unicellular green alga Haematococcus pluvialis has recently attracted great interest due to its large amounts of ketocarotenoid astaxanthin, 3,3'-dihydroxy-ββ,ββ-carotene-4,4'-dione, widely used commercially as a source of pigment for aquaculture. In the life cycle of H. pluvialis, astaxanthin biosynthesis is associated with a remarkable morphological change from green motile vegetative cells into red immotile cyst cells as the resting stage. In recent years we have studied this morphological process from two aspects: defining conditions governing astaxanthin biosynthesis and questioning the possible function of astaxanthin in protecting algal cells against environmental stress. Astaxanthin accumulation in cysts was induced by a variety of environmental conditions of oxidative stress caused by reactive oxygen species, intense light, drought, high salinity, and high temperature. In the adaptation to stress, abscisic acid induced by reactive oxygen species, would function as a hormone in algal morphogenesis from vegetative to cyst cells. Furthermore, measurements of both in vitro and in vivo antioxidative activities of astaxanthin clearly demonstrated that tolerance to excessive reactive oxygen species is greater in astaxanthin-rich cysts than in astaxanthin-poor cysts or astaxanthin-less vegetative cells. Therefore, reactive oxygen species are involved in the regulation of both algal morphogenesis and carotenogenesis, and the accumulated astaxanthin in cysts can function as a protective agent against oxidative stress damage. In this study, the physiological roles of astaxanthin in stress response and cell protection are reviewed.

Long-term outcomes of progestin plus metformin as a fertility-sparing treatment for atypical endometrial hyperplasia and endometrial cancer patients

Akira Mitsuhashi,Yuji Habu,Tatsuya Kobayashi,Yoshimasa Kawarai,Hiroshi Ishikawa,Hirokazu Usui,Makio Shozu 대한부인종양학회 2019 Journal of Gynecologic Oncology Vol.30 No.6

Objective: The present study investigated long-term outcomes of medroxyprogesteroneacetate (MPA) plus metformin therapy in terms of control of atypical endometrial hyperplasia(AEH) and endometrial cancer (EC), and post-treatment conception. Methods: We retrospectively analyzed 63 patients (42 with EC; 21 with AEH) who underwentfertility-sparing management using MPA plus metformin. MPA (400 mg/day) and metformin(750–2,250 mg/day) were administered to achieve complete response (CR). Metformin wasadministered until conception, even after MPA discontinuation. Results: Of the total patients, 48 (76%) had a body mass index (BMI) ≥25 kg/m2 and 43 (68%)showed insulin resistance. Sixty-one patients (97%) achieved CR within 18 months. CR ratesat 6, 8–9, and 12 months were 60%, 84%, and 90%, respectively. During a median followupperiod of 57 months (range, 13–115 months), relapse occurred in 8 of 61 patients (13.1%)who had achieved CR. Relapse-free survival (RFS) in all patients at 5 years was 84.8%. Uponunivariate analysis, patients with BMI ≥25 kg/m2 had significantly better prognoses than didthose with BMI <25 kg/m2 (odds ratio=0.19; 95% confidence interval=0.05–0.66; p=0.009). Overall pregnancy and live birth rates per patient were 61% (19/31) and 45% (14/31), respectively. Conclusions: MPA plus metformin is efficacious in terms of RFS and post treatmentconception. Moreover, metformin may be more efficacious for patients with BMI ≥25 kg/m2.

Histopathological examination following side-by-side placement of metal stents for malignant hilar biliary obstruction

Hiroshi Nakagawara,Kenji Yamao,Takuji Gotoda,Daiichiro Kikuta,Akinori Takei,Kunio Iwatsuka,Toshimi Takahashi,Masahiro Ogawa,Akihiro Henmi,Makio Kobayashi,Mitsuhiko Moriyama 소화기인터벤션의학회 2019 Gastrointestinal Intervention Vol.8 No.2

Background: Endoscopic-guided placement of metal stents for unresectable malignant hilar biliary obstruction (UMHBO) is performed using partial stent-in-stent or side-by-side (SBS) techniques. The latter involves placing sequential stents within the bile duct. Excessive dilation of the bile duct during stent placement can have serious effects on the surrounding organs.Methods: This study details seven cases of SBS placement of 8.0 mm metal stents for UMHBO. Histopathological examinations were performed to identify the effects on the bile duct and surrounding tissues.Results: The mean post-placement diameter of the bile ducts was 13.86 mm, and no compression necrosis or thrombi were observed in surrounding tissues. Cholangitis occurred in five cases, and death occurred as a result of cholecystitis in one case. Conclusion: The use of 8.0-mm stents for SBS is unlikely to have major negative effects on peribiliary tissues and blood vessels. However, post-placement cholecystitis can result in increased mortality; thus, gallbladder drainage should be considered.

Histopathological examination following side-by-side placement of metal stents for malignant hilar biliary obstruction

Hiroshi Nakagawara,Kenji Yamao,Takuji Gotoda,Daiichiro Kikuta,Akinori Takei,Kunio Iwatsuka,Toshimi Takahashi,Masahiro Ogawa,Akihiro Henmi,Makio Kobayashi,Mitsuhiko Moriyama 소화기인터벤션의학회 2019 International journal of gastrointestinal interven Vol.8 No.2

Background: Endoscopic-guided placement of metal stents for unresectable malignant hilar biliary obstruction (UMHBO) is performed using partial stent-in-stent or side-by-side (SBS) techniques. The latter involves placing sequential stents within the bile duct. Excessive dilation of the bile duct during stent placement can have serious effects on the surrounding organs.Methods: This study details seven cases of SBS placement of 8.0 mm metal stents for UMHBO. Histopathological examinations were performed to identify the effects on the bile duct and surrounding tissues.Results: The mean post-placement diameter of the bile ducts was 13.86 mm, and no compression necrosis or thrombi were observed in surrounding tissues. Cholangitis occurred in five cases, and death occurred as a result of cholecystitis in one case. Conclusion: The use of 8.0-mm stents for SBS is unlikely to have major negative effects on peribiliary tissues and blood vessels. However, post-placement cholecystitis can result in increased mortality; thus, gallbladder drainage should be considered.