Two Novel QTLs for the Harvest Index that Contribute to High-Yield Production in Rice (Oryza sativa L.).

BACKGROUND: The harvest index (HI) is a measure of the biological success of forming harvestable products. However, our understanding of the genetic basis of HI in rice (Oryza sativa L.) is limited, because it is a complex trait consisting of various yield-related traits and physiological attributes. YTH183 is a high-yielding line with large panicles and high HI derived from a cross between the Indica Group variety IR 64 and the NPT line IR 69093-41-2-3-2 (YP5). RESULTS: Here, we detected two novel QTLs for HI, designated qHI5.1 on chromosome 5 and qHI8.1 on chromosome 8, by using 155 recombinant inbred lines (RILs) derived from the cross between IR 64 and YTH183. The YTH183 allele at qHI5.1 contributed to a wide grain, resulting in heavy grain weight and panicle weight, and was consistently effective under the different environmental conditions of subtropical (Ishigaki) and temperate (Tsukuba) regions. Genetic polymorphism revealed that qHI5.1 was identical to GSE5/GW5, which is known to control the grain weight. On the other hand, although qHI8.1 functioned additively with qHI5.1 for higher HI, it did not show any significant effect on grain or panicle weight. In addition, its effects on HI were shown only in the first seasons at Ishigaki but not at Tsukuba or in the second season at Ishigaki. CONCLUSION: Our results indicate that qHI5.1 controls the grain size, regardless of whether environmental conditions are of subtropical or temperate regions, while qHI8.1 might be involved in controlling the physiological processes of source ability or the translocation of photosynthesis products from vegetative organs to grains depending on environmental conditions during the maturing stage. These QTLs will be useful genetic resources for future breeding programs to break through the ceiling of maximum yield in Indica Group varieties.

Genetic variation of blast (Pyricularia oryzae Cavara) resistance in rice (Oryza sativa L.) accessions widely used in Kenya.

A total of 47 rice accessions collected from Kenya were investigated the genetic variations and classified into two cluster groups, A and B, by polymorphism data of 65 simple sequence repeat (SSR) markers. Clusters A and B corresponded to Japonica and Indica Groups, respectively. The number of Japonica Group accessions was limited in comparison with those of the Indica Group. Based on their patterns of reaction to standard differential blast isolates (SDBIs), these accessions and 57 control cultivars including differential varieties and several accessions harboring partial resistance genes were classified again into three cluster groups: Ia (high resistance), Ib (intermediate resistance) and II (susceptible). The rice accessions from Kenya were classified only into groups Ia and Ib. The accessions from Kenya were finally classified into three categories, A-Ia, B-Ia and B-Ib, based on the two classifications of polymorphism of SSR markers and resistance. The Indica Group accessions had wider genetic variation for blast resistance than did the Japonica Group accessions. The three leading cultivars (Basmati 217, Basmati 370 and ITA 310) categorized into Cluster group Ia were susceptible to some SDBIs from Kenya. The genetic variation for blast resistance in Kenya was demonstrated as the first report using SDBIs.

Genetic variation of root angle distribution in rice (Oryza sativa L.) seedlings.

We developed a new method of using seedling trays to evaluate root angle distribution in rice (Oryza sativa. L), and found a wide genetic variation among cultivars. The seedling tray method can be used to evaluate in detail the growth angles of rice crown roots at the seedling stage by allocating nine scores (10° to 90°). Unlike basket methods, it can handle large plant populations over a short growth period (only 14 days). By using the method, we characterized the root angle distributions of 97 accessions into two cluster groups: A and B. The numbers of accessions in group A were limited, and these were categorized as shallow rooting types including soil-surface root. Group B included from shallow to deep rooting types; both included Indica and Japonica Group cultivars, lowland and upland cultivars, and landraces and improved types. No relationship between variation in root vertical angle and total root number was found. The variation in root angle distribution was not related to differentiation between the Japonica and Indica Groups, among ecosystems used for rice cultivation, or among degrees of genetic improvement. The new evaluation method and associated information on genetic variation of rice accessions will be useful in root architecture breeding of rice.

Genetic variation in resistance to blast (Pyricularia oryzae Cavara) in rice (Oryza sativa L.) germplasms of Bangladesh.

Genetic variation in blast resistance was clarified in 334 Bangladesh rice accessions from 4 major ecotypes (Aus, Aman, Boro and Jhum). Cluster analysis of polymorphism data of 74 SSR markers separated these accessions into cluster I (corresponding to the Japonica Group) and cluster II (corresponding to the Indica Group). Cluster II accessions were represented with high frequency in all ecotypes. Cluster II was further subdivided into subclusters IIa and IIb. Subcluster IIa accessions were represented with high frequency in only Aus and Jhum ecotypes. Cluster I accessions were more frequent in the Aman ecotype than in other ecotypes. Distinct variations in resistance were found, and accessions were classified into 4 groups (A1, A2, B1 and B2) based on their reactions to standard differential blast isolates. The most susceptible group was A2 (which included susceptible variety Lijiangxintuanheigu, most of the differential varieties, and a few Bangladesh accessions), followed in order by A1, B2 and B1 (the most resistant). Accessions from 4 ecotypes fell with different frequencies into each of these resistance groups. These results demonstrated that Japonica Group accessions were found mainly in Aman, and Indica Group accessions were distributed across all ecotypes. Susceptible accessions were limited in Aus and Aman.

[A Case of Cardiac Arrest following Intra-articular Administration of Levobupivacaine during Total Knee Arthroplasty].

A 73-year-old woman with normal cardiac function underwent an elective total knee arthroplasty. After skin closure, levobupivacaine 225 mg was injected into the knee and 25 mg was injected subcutaneously. The patient recovered from general anesthesia 5 min after the surgery. Thirty five min after surgery, while in general radiology department her carotid arterial pulses were not palpable. Cardiopulmonary resuscitation (CPR) was initiated with intravenous (i.v.) administration of adrenaline 1 mg. Circulation was rapidly restored. Coronary angiography demonstrated no coronary stenosis; however, left ventriculography demonstrated takotsubo cardiomyopathy. The patient regained consciousness, but pulmonary edema and renal failure became worse. On postoperative day 2, continuous hemodialysis was instituted. Weaning from ventilatory support was completed on postoperative day 3; hemodialysis was stopped on day 14; and the patient left the intensive care unit on day 15. We believe cardiac arrest may have been precipitated by local anesthetic systemic toxicity (LAST), and administration of i. v. adrenaline 1 mg may have resulted in pulmonary edema. Patients should be carefully observed following local anesthetic with attention given to the side-effects of i. v. adrenaline.

Identification of a low tiller gene from a new plant type cultivar in rice (Oryza sativa L.).

We characterized a rice introgression line, YTH34, harboring a chromosome segment from a New Plant Type (NPT) cultivar, IR65600-87-2-2-3, in the genetic background of an Indica Group elite rice cultivar, IR 64, under upland and irrigated lowland conditions in Japan. The number of panicles (as an indicator of tiller number) and number of spikelets per panicle of YTH34 were lower than those of IR 64 under irrigated lowland conditions, but both of those as well as culm length, panicle length, seed fertility, panicle weight, whole plant weight, and harvest index were dramatically reduced under upland conditions. And the low tiller of YTH34 was confirmed to start after the maximum tiller stage. In particular, the decrease of panicle number was remarkable in upland, so we tried to identify the chromosome location of the relevant gene. Through segregation and linkage analyses using F3 family lines derived from a cross between IR 64 and YTH34, and SSR markers, we found that low tiller number was controlled by a single recessive gene, ltn2, and mapped with the distance of 2.1 cM from SSR marker RM21950, in an introgressed segment on chromosome 7. YTH34 harboring ltn2 and the genetic information for DNA markers linked will be useful for genetic modification of plant architectures of Indica Group rice cultivar.

[Postoperative Analgesia in Peritonectomy for Patients with Peritoneal Surface Malignancy].

BACKGROUND: We investigated the efficacy of postoperative analgesia in peritonectomy for patients with peritoneal surface malignancy, by comparing peripheral nerve block (PNB) with intravenous patient controlled analgesia (iv-PCA) group to patient controlled epidural analgesia (PCEA) group. METHODS: Forty one patients of PNB+iv-PCA group received ultrasound guided rectus sheath block (using 0.25% levobupivacaine 20 ml bilaterally) and posterior transversus abdominis plane block (30 ml bilaterally) after induction of anesthesia. Then, iv-PCA with fentanyl was commenced before skin incision and 10 mg morphine was given 1 hr before the end of surgery. Fifty eight patients of PCEA group received 5-6 mg morphine epidural block at T6-7 or T7-8 before induction of anesthesia, and PCEA of 4-5 mg morphine and 200 ml normal saline was commenced before skin incision. When PCA showed inadequate effect for post- operative pain, flurbiprofen was used for all patients. RESULTS: The rate of administration of flurbiprofen during the first 24 hr after surgery was significantly lower in PNB+iv-PCA group. The duration of the first administration of flurbiprofen after extubation was significantly longer in PNB+iv-PCA group. Levobupivacaine (0.25%) 100 ml for PNB was safe to use without complications. CONCLUSIONS: PNB+iv-PCA decreased the rate of administration of flurbiprofen as compared to PCEA for postoperative pain after peritonectomy.

[Influence of remifentanil on postoperative pain with intravenous patient-controlled analgesia following total knee arthroplasty].

BACKGROUND: There is a controversy about the development of acute opioid tolerance during remifentanil infusion for postoperative pain. We investigated whether intraoperative remifentanil infusion leads to rapid development of tolerance. We also investigated whether adjuvant analgesic is effective or not. METHODS: One hundred and thirty patients scheduled for TKA were divided into 4 groups; Non-remifentanil infusion group (30 patients; group A). This group was given a bolus of fentanyl 0.2 mg at the induction of anesthesia. In remifentanil anesthesia group (100 patients), remifentanil was given 0.2-0.3 microg x kg(-1) min(-1) and divided into three groups; 23 patients group B given a bolus of 0.2 mg fentanyl at induction of anesthesia, 38 patients group C given a bolus of fentanyl 0.2 mg at skin closure, and 39 patients group D given a bolus of fentanyl 0.2 mg at skin closure and administrated diclofenac sodium suppository rectally at induction of anesthesia. Intravenous patient controlled analgesia (PCA) of fentanyl was commenced before skin incision for all patients. Pain was scored at rest and during movement for 24 postoperative hours. RESULTS: Numerical rating scale (NRS) scores during movement after 24 hours in group B were significantly higher than in group A. And, the NRS scores in group D tended to be lower than the other groups, but there were no significant differences. CONCLUSIONS: Intraoperative remifentanil increased postoperative pain during movement. Remifentanil seems to cause acute torelance. NSAIDs given before operation may be useful for postoperative analgesia.

[Blood transfusion therapy for massive hemorrhage associated with scheduled peritonectomy for pseudomyxoma peritonei and peritoneal dissemination].

BACKGROUND: The component therapy has been recommended for surgical hemorrhage. We investigated whether the component therapy was useful for surgical patients undergoing the scheduled peritonectomy for pseudomyxoma peritonei or peritoneal dissemination. METHODS: Twenty patients were divided into two groups (the component therapy for 7 patients and the early transfusion of flesh frozen plasma therapy for 13 patients). We studied the change of prothrombin time (PT), hepaplastin test (HPT) and fibrinogen level during operations. RESULTS: In the component therapy group, PT, HPT and fibrinogen level decreased to 28.5 +/- 11.8%, 25.9 +/- 9.3%, 99.5 +/- 61.3 mg x dl(-1), respectively, during surgical intervention, but no difference was found postoperatively between the two groups. One patient in the component therapy group was reoperated for bleeding. CONCLUSIONS: If the hemorrhage of more than the circulation volume is suspected before the operation, early transfusion therapy seems to provide good effect for coagulation in scheduled peritonectomy of pseudomyxoma peritonei or peritoneal dissemination.