Generation, identification, formation mechanism and application of plant haploids.

Haploids are individuals with gametophytic chromosome numbers. Homozygous doubled haploids can be quickly gained by genome doubling. Haploids and doubled haploids play an important role on crop breeding, mutant screening, gene functional analysis, cytological studies, construction of genetic population and so on, and have been a research hotspot of plants in recent years. In this review, we summarize the production means, identification, the genetic mechanism and the applications of haploids and doubled haploids. We hope to provide a reference for study and application of haploids and doubled haploids.

[The effect of different intensity exercise on skeletal muscle fiber MHC subtype transformation and CaN/NFATc1 signaling pathways].

OBJECTIVE: To study the effect of different intensity exercise on skeletal muscle fiber myosin heavy chain(MHC) subtype transformation and CaN/NFATc1 signaling pathways. METHODS: Twenty-four Male SD rats (2-month old) were randomly divided into normal control group (NC), moderate intensity exercise group (ME, grade 5°, speed 18 m/min), heavy intensity exercise group (HE, grade 10°, 26.8 m/min). The rats in exercise groups were treated with treadmill training for eight weeks. The type I and type Ⅱ muscle fibers were determined by ATPase staining method. MHC subtype was separated by SDS-PAGE. The activity of CaN was determined by colorimetric method. The content of NFATc1 protein in skeletal muscle was detected by immune imprinting technology. RESULTS: ①Skeletal muscle fiber density changes:the type I and Ⅱ fiber number density of quadriceps in ME group were increased significantly (P<0.05), but in HE group, only the type Ⅱ fiber surface density was increased significantly (P<0.05). The type I fiber number density of soleus in ME and HE group was increased significantly (P<0.05). ②The changes of fibers MHC subtype percentage in skeletal muscle:the percentages of MHC I and type Ⅱa of quadriceps in ME group were increased (P<0.05), while the percentage of MHC Ⅱb was decrease (P<0.05). The percentage of MHC I in soleus was increased, while the percentages of MHCⅡa and Ⅱb were decreased. ③The activity of CaN and the content of NFATc1 protein in ME group were increased significantly (P<0.05). CONCLUSIONS: The heavy and moderate intensity exercise may induce skeletal muscle MHC type transforming from fast to slow. At the same time, the activity of CaN and the expression of NFATc1 protein are increased accompanying the changes of skeletal muscle fibers subtype.

[Neonatal group B streptococcus infection in the Children's Hospital of Gansu Province through PCR array].

OBJECTIVE: To study neonatal Streptococcus agalactiae (GBS) infection in The Children's Hospital of Gansu Province through Polymerase Chain Reaction(PCR) Array. METHOD: After obtaining the informed consent from parents or guardians, blood samples of 286 neonates were collected and studied in The Children's Hospital of Gansu Province from June 2011 to January 2012. DNA of the selected samples was extracted through the method of 5% Chelex-100 + 0.5% NP40 solution. Twenty-five genes were ultimately selected and then 25 pairs of primers were designed respectively through primer-BLAST tool of NCBI database.For every primer, PCR conditions were optimized through the identified GBS, and 25 pairs of primers were arrayed as to be used to study neonatal GBS infection. RESULT: The results of PCR Array showed that the 14 samples were detected positive, accounting for 4.90% of all the selected specimens. As for neonatal GBS infection, the positive rate was 4.55% within 7 days after birth and 5.19% in those older than 7 days. The positive rate of 53 preterm infants was 5.66%. The follow-up survey showed that none of the cases died. CONCLUSION: In the Children's Hospital of Gansu Province neonatal GBS infection rate was 4.90%, which is similar to the previous domestic reports, but is lower than the reports from Europe and the United States.Studies have shown that the gene expression related to immune evasion has a higher frequency. The present study suggests that the strategy of GBS immune adaptation may play an important role in neonatal GBS infection.