Establishment of a prediction model for the miRNA-based heading date characteristics of rice in the booting stage.

Rice (Oryza sativa L.) is one of the most important food crops in the world. In Taiwan, due to the warm climate, there are two harvests annually. However, the yield and quality of rice can vary between each crop season in any given year. Previous reports have shown that microRNAs (miRNAs) play a crucial role in many developmental and physiological processes in plants. In this study, the heading date characteristics of 167 rice cultivars from the second crop season were recorded, and 27 rice cultivars were selected for preliminary microarray analysis. A total of 14 miRNAs from different heading date characteristics in 21 cultivars were selected based on significant differences in their expression profiles. Using a correlation analysis between the heading date and selected miRNA expression obtained from real-time polymerase chain reaction (PCR) assays, we developed a heading date prediction model. The model includes nine miRNA genes with corresponding R2 values of 0.8. To confirm the model, a real-time PCR analysis was performed on an additional 27 rice cultivars and we found the model predicted the heading date with accuracy. Therefore, the developed prediction may be useful in further studies aimed at confirming the reliability of the use of miRNA in molecular breeding and to increase the selection efficiency of rice cultivars and breeding.

Sexual genetic and simple sequence repeat (SSR) analysis for molecular marker development on the all hermaphrodite papaya.

The papaya (Carica papaya L.) is one of the most important economic tropical fruits in the world, and the hermaphrodite is the preferred type in field cultures. We analyzed the sexual ratio of offspring from the cultivar 'Taiwan Seed Station No. 7' (T7) by a self-cross and its cross with Taichung Sunrise (TS). Female progeny from the T7 self-crossing were not observed. This finding may be caused by a lethal gene that is linked to females. In this study, we selected 192 simple sequence repeats (SSRs) to analyze the polymorphism between T7 and TS. A total of 37 SSRs were identified for T7 and TS. In addition, 14 SSRs served as the molecular makers for identification of T7, TS and their hybrid offsprings. Thus, the results show that the genetic similarity between T7 and TS is rather high. This suggests that T7 may be a mutant of TS. Phylogenetic analysis from the SSR polymorphisms of the above parent strains and 15 F1 offspring revealed the genetic distance of the F1 offspring located between T7 and TS. The results of this study may provide an opportunity for elucidating the genetic characteristics of all hermaphrodites via identification of molecular makers.

Analysis of sequence diversity through internal transcribed spacers and simple sequence repeats to identify Dendrobium species.

The Orchidaceae is one of the largest and most diverse families of flowering plants. The Dendrobium genus has high economic potential as ornamental plants and for medicinal purposes. In addition, the species of this genus are able to produce large crops. However, many Dendrobium varieties are very similar in outward appearance, making it difficult to distinguish one species from another. This study demonstrated that the 12 Dendrobium species used in this study may be divided into 2 groups by internal transcribed spacer (ITS) sequence analysis. Red and yellow flowers may also be used to separate these species into 2 main groups. In particular, the deciduous characteristic is associated with the ITS genetic diversity of the A group. Of 53 designed simple sequence repeat (SSR) primer pairs, 7 pairs were polymorphic for polymerase chain reaction products that were amplified from a specific band. The results of this study demonstrate that these 7 SSR primer pairs may potentially be used to identify Dendrobium species and their progeny in future studies.

Proline partially overcomes excess molybdenum toxicity in cabbage seedlings grown in vitro.

In vitro grown cabbage (Brassica oleracea var. capitata) seedlings exposed to excess molybdenum (Mo) ions exhibited severely reduced plant growth at the cotyledonary stage. Adding 80 mM proline (Pro) to the Mo-treated medium could help 50% seedlings to overcome the toxicity and grow true leaves. Under excess Mo stress, seedlings accumulated blue/purple anthocyanin in their cotyledons and hypocotyls. The anthocyanin content under Mo with 40 mM Pro was 4-fold higher than the control medium, MS with 40 mM Pro. The presence of Pro in the excess-Mo condition reduced chlorophyll a, whereas the chlorophyll b content was much higher than the control media of MS with and without Pro. Moreover, supplementing various concentrations of Pro into the Mo-stressed condition promoted the seedlings with higher antioxidant enzyme activities of superoxide dismutase, ascorbate peroxidate, and catalase. In addition, genes in the anthocyanin biosynthesis and accumulation pathways, phenylalanine ammonia lyase (PAL), chalcone synthase (CHS), flavonone 3-hydroxylase (F3H), leucoanthocyanidin dioxygenase (LDOX), and glutathione-S-transferase (GST), were all upregulated. Our study indicated that, under excess Mo stress, the antioxidant activity of cabbage seedlings was induced in an attempt to protect plants from the Mo-induced toxicity and exacerbated growth. Pro, on the other hand, functioned in producing higher antioxidant enzyme activity to partially help recover plant growth.

Production of interspecific hybrids between commercial cultivars of the eggplant (Solanum melongena L.) and its wild relative S. torvum.

Interspecific hybrids between cultivars of eggplant (Solanum melongena L.) and its wild relative S. torvum, which has disease resistance and desirable traits for crop improvement, were obtained by cross-hybridization and embryo rescue. Twenty-one hybrid progenies were obtained and examined based on morphological traits, RAPD and ISSR markers. Five of them were confirmed to be true interspecific hybrids. Eighteen and 14 bands from 7 RAPD and 14 ISSR primers, respectively, were polymorphic and present in all five hybrid seedlings and their parents. The morphological characteristics of leaf margin, inflorescence type and spine positions of the five seedlings were intermediate to the parents. These interspecific hybrids had low pollen viability, probably due to abnormal meiosis.

A simplified schedule to integrate the hepatitis B vaccine into an expanded program of immunization in endemic countries.

OBJECTIVE: To investigate the safety, immunogenicity, and efficacy of a simplified hepatitis B vaccination schedule. METHODS: The second dose of hepatitis B vaccine and the first dose of diphtheria-tetanus-pertussis (DTP) vaccine were given simultaneously at age 6 weeks. The second dose of DTP vaccine was given at age 3.5 months. The third dose of DTP vaccine and the third dose of hepatitis B vaccine were given at age 5.5 months. One hundred three infants (group A) born to mothers without hepatitis B surface antigen (HBsAg) received DTP with whole-cell pertussis vaccine. Fifty-five infants (group B) born to mothers with HBsAg and hepatitis B e antigen received DTP with acellular pertussis vaccine. RESULTS: By age 9 months, none of group A and 4 (7%) group B infants were sero-positive for HBsAg. The protective efficacy against the hepatitis B carrier state in these infants at high risk was 92%. Antibody to hepatitis B surface antigen was 10 mlU/ml or greater in 99 (96%) of group A infants and in 50 (91%) of group B infants. Both the acellular and whole-cell DTP vaccines were immunogenic, and the incidences of adverse reactions were within an expected and acceptable range. CONCLUSIONS: The simplified vaccination schedule to integrate the hepatitis B vaccine into the Expanded Programme of Immunization was safe, Immunogenic, and effective. This schedule may improve vaccine compliance and be applied to DTP and hepatitis B combination vaccines now under investigation.

Long-term efficacy of recombinant hepatitis B vaccine and risk of natural infection in infants born to mothers with hepatitis B e antigen.

To evaluate the long-term protection afforded by the vaccine, recombinant hepatitis B (HB) vaccine was given to 171 infants born to hepatitis B e antigen-positive carrier mothers. Group A (53 infants) and group B (57 infants) received four doses of HB vaccine at birth and at 1, 2, and 12 months of age, with a dose of 20 micrograms in group A and 10 micrograms in group B. Group C (61 infants) received three 20 micrograms doses of HB vaccine at birth and at 1 and 6 months of age. These children were followed up annually up to 5 years of age. Six children (4%) became HB carriers before 1 year of age, and the carrier state persisted to the end of follow-up. The overall seropositive rate of HB surface antibody (anti-HBs) dropped from 99% at 1 year of age to 83% at 5 years of age. Among 548 serum pairs taken at 1-year intervals from children negative for HB surface antigen (HBsAg), a fourfold rise of anti-HBs titer was noted in 58 (11%) and a 10-fold rise of anti-HBs was noted in 17 (3%). Maternal HB core antibody disappeared in most children (151/152, 99%) before 2 years of age. Natural infections, as judged by persistence or reappearance of HB core antibody, occurred in 19 of 163 (12%) HBsAg-negative children. None of these episodes was associated with HBsAg positivity. We conclude that the long-term protection afforded by recombinant HB vaccine is satisfactory and that a further booster dose before 5 years of age is not necessary.

Factors affecting clearance of hepatitis B e antigen in hepatitis B surface antigen carrier children.

To understand the natural history of chronic hepatitis B virus infection in children, we studied factors affecting the clearance of hepatitis B e antigen (HBeAg). One hundred sixty-nine apparently healthy children whose sera were positive for HBeAg and hepatitis B surface antigen (HBsAg) and who were recruited by screening were followed prospectively to delineate the HBeAg clearance rate. Another 59 carrier children visiting the outpatient clinic because of symptoms or abnormal liver function were studied for comparison. The annual HBeAg clearance rate was low (less than 2%) during the first 3 years of life but increased with age. The HBeAg clearance rate in children older than 6 years of age was lower in those whose mothers had HBsAg positivity (14.3%) than in those whose mothers had no detectable HBsAg (35.3%). Children who were brought for medical care had higher HBeAg clearance rates (42.4%) than those who were recruited by screening (14.6%) because immune clearance of hepatitis B virus and hence HBeAg often led to hepatocellular damage manifested by abnormal liver function profiles or by symptoms that had caused the parents to seek medical care for their children. We conclude that age, source of subject recruitment, and maternal HBsAg status are important factors affecting HBeAg clearance rate in HBsAg carriers.

Is direct cardiotoxicity the primary cause of death following i.v. injection of the basic phospholipase A2 from Naja nigricollis venom?

The primary cause of death following i.v. injection of the basic phospholipase A2 (PLA2) from Naja nigricollis venom has been attributed to its direct cardiotoxicity. In view of our recent findings that cardiac failure caused by the basic PLA2 from Naja m. mossambica is primarily due to hyperkalemia resulting from cellular damage and possibly also from hemolysis, the cause of death due to the basic PLA2 from Naja nigricollis was re-investigated. In the anesthetized mice and rats, the PLA2 (0.3 micrograms/g, i.v.) produced a transient hypotension followed by recovery and subsequently by cardiac failure with ECG changes suggestive of hyperkalemia, such as P-R prolongation, tall T-wave, biphasic QRS-T complex, low voltage of QRS, A-V block, etc. Analysis of blood chemistry revealed marked increases in the plasma levels of K+, CPK, LDH, GOT, GPT, inorganic phosphate and hemoglobin (probably a mixture of hemoglobin and myoglobin). In the atrial preparation, however, no marked cardiotoxicity was observed except for a slight negative inotropic effect at 30 micrograms/ml. When 200 micrograms of the enzyme was injected into the coronary circulation in the Langendorff preparation, also no marked cardiotoxic effect was observed except for a decrease (about 40%) of coronary flow. From these results, it is concluded that the primary cause of death following i.v. injection of the basic PLA2 from Naja nigricollis is apparently cardiac failure due to hyperkalemia, resulting from cellular damage and possibly also from hemolysis, rather than direct cardiotoxicity.

Is direct cardiotoxicity the primary cause of death following i. v. injection of the basic phospholipase A2 from Naja Nigricollis venom?

Con objeto de elucidar la función del Ca intracelular en la transmisión neuromuscular investigamos en preparaciones de músculo de rana los efectos del ácido1,2-bis(o-aminofenoxi)etano-N,N,N',N'-tetraacético (BAPTA) sobre el aumento-potenciación por frecuencia (anteriormente llamado facilitación por frecuencia) el que ha sido de utilidad para identificar los sitios de acción de varios agentes colinérgicos. La disminución de los iones Ca del espacio intracelular por BAPTA sólo suprimió el componente dependiente de Ca del fenómeno (ma) sin modificar el factor de estimulación dependiente de frecuencia (K). La depresión causada por BAPTA en la facilitación de corto plazo del potencial de placa (EPP) fue la misma tanto en reposo como en la estimulación. El efecto del BAPTA fue parcialmente antagonizado, por el ionóforo de Ca A23187. Esto sugiere que la capacidad de "buffer" de Ca del BAPTA se mantiene durante la estimulación repetitiva de baja frecuencia. BAPTA no modificó la potenciación post-tetánica de los EPP miniatura en medio libre de Ca. Estos resultados indican que los iones Ca son esenciales para la liberación de transmisor y para la facilitación de corto plazo, pero no son responsables de todos los cambios en la liberación de transmisor

Is direct cardiotoxicity the primary cause of death following i.v. injection of the basic phospholipase A2 from Naja nigricollis venom?

The primary cause of death following i.v. injection of the basic phospholipase A2 (PLA2) from Naja nigricollis venom has been attributed to its direct cardiotoxicity. In view of our recent findings that cardiac failure caused by the basic PLA2 from Naja m. mossambica is primarily due to hyperkalemia resulting from cellular damage and possibly also from hemolysis, the cause of death due to the basic PLA2 from Naja nigricollis was re-investigated. In the anesthetized mice and rats, the PLA2 (0.3 micrograms/g, i.v.) produced a transient hypotension followed by recovery and subsequently by cardiac failure with ECG changes suggestive of hyperkalemia, such as P-R prolongation, tall T-wave, biphasic QRS-T complex, low voltage of QRS, A-V block, etc. Analysis of blood chemistry revealed marked increases in the plasma levels of K+, CPK, LDH, GOT, GPT, inorganic phosphate and hemoglobin (probably a mixture of hemoglobin and myoglobin). In the atrial preparation, however, no marked cardiotoxicity was observed except for a slight negative inotropic effect at 30 micrograms/ml. When 200 micrograms of the enzyme was injected into the coronary circulation in the Langendorff preparation, also no marked cardiotoxic effect was observed except for a decrease (about 40

) of coronary flow. From these results, it is concluded that the primary cause of death following i.v. injection of the basic PLA2 from Naja nigricollis is apparently cardiac failure due to hyperkalemia, resulting from cellular damage and possibly also from hemolysis, rather than direct cardiotoxicity.

Is direct cardiotoxicity the primary cause of death following i. v. injection of the basic phospholipase A2 from Naja Nigricollis venom?

Con objeto de elucidar la función del Ca intracelular en la transmisión neuromuscular investigamos en preparaciones de músculo de rana los efectos del ácido1,2-bis(o-aminofenoxi)etano-N,N,N,N-tetraacético (BAPTA) sobre el aumento-potenciación por frecuencia (anteriormente llamado facilitación por frecuencia) el que ha sido de utilidad para identificar los sitios de acción de varios agentes colinérgicos. La disminución de los iones Ca del espacio intracelular por BAPTA sólo suprimió el componente dependiente de Ca del fenómeno (ma) sin modificar el factor de estimulación dependiente de frecuencia (K). La depresión causada por BAPTA en la facilitación de corto plazo del potencial de placa (EPP) fue la misma tanto en reposo como en la estimulación. El efecto del BAPTA fue parcialmente antagonizado, por el ionóforo de Ca A23187. Esto sugiere que la capacidad de "buffer" de Ca del BAPTA se mantiene durante la estimulación repetitiva de baja frecuencia. BAPTA no modificó la potenciación post-tetánica de los EPP miniatura en medio libre de Ca. Estos resultados indican que los iones Ca son esenciales para la liberación de transmisor y para la facilitación de corto plazo, pero no son responsables de todos los cambios en la liberación de transmisor (AU)

Hepatitis D virus infection in children with acute or chronic hepatitis B virus infection in Taiwan.

To investigate the prevalence and clinical features of hepatitis D virus infection (HDV) in childhood, total antibody to hepatitis D antigen (anti-HD) in serum samples from 247 children (29 with acute hepatitis B, 68 with chronic hepatitis B, and 150 with asymptomatic hepatitis B surface antigen (HBsAg) carriers with normal liver function profiles) were studied using solid-phase competitive radioimmunoassay. Anti-HD was detected in three of the 29 children with acute hepatitis B and in only one of the 68 with chronic hepatitis B; none of the serum specimens from 150 asymptomatic carriers with normal liver function profile showed detectable anti-HD. All three children with HDV coinfection cleared HBsAg and seroconverted to anti-HBs, whereas one with superinfection finally had normal liver function without clearance of HBsAg. To identify possible sources of HDV infection, HBV markers and anti-HD in family members were also examined. One 4-month-old infant boy became infected through a blood transfusion from his hepatitis B e antigen (HBeAg)-positive carrier father, who had anti-HD. A 4-month-old infant girl was infected through close contact with her HBeAg-negative carrier father, who had HDV superinfection. The infection sources remained undefined in another two patients. The mothers of these four children were seronegative for anti-HD, indicating that perinatal transmission is not the usual mode of HDV infection in Taiwan. The natural course of either acute or chronic HBV infections in childhood in Taiwan may be more closely related to HBV itself, or to some other yet unrecognized factor, rather than to HDV infection.

Fulminant hepatitis in children in Taiwan: the important role of hepatitis B virus.

In a recent period of 64 months, fulminant hepatitis was diagnosed in 17 children at National Taiwan University Hospital. Eleven patients were younger than 12 months of age. Hepatitis A IgM antibody and delta-antibody were negative in all 17. Eleven (65%) patients had hepatitis B core IgM antibody, fulminant hepatitis B. Two to 5 months before onset of hepatitis. Five of the 11 children had received blood transfusions. Three of the five donors had hepatitis B e antibody (anti-HBe) and were hepatitis B virus DNA-negative hepatitis B surface antigen (HBsAg) carriers; another two were HBsAg negative, screened by a less sensitive reverse passive hemagglutination method. The mothers of all six infants younger than 6 months of age had HBsAg. HBe antigen and antibody were studied in five of these six mothers; all five had anti-HBe. We conclude that hepatitis B virus is the most important cause of fulminant hepatitis in children in Taiwan.