Structural evolution and functional diversification analyses of argonaute protein.

Argonaute (AGO) proteins are highly specialized small-RNA-binding modules and small RNAs are anchored to their specific binding pockets guiding AGO proteins to target mRNA molecules for silencing or destruction. The 135 full-length AGO protein sequences derived from 36 species covering prokaryote, archaea, and eukaryote are chosen for structural and functional analyses. The results show that bacteria and archaeal AGO proteins are clustered in the same clade and there exist multiple AGO proteins in most eukaryotic species, demonstrating that the increase of AGO gene copy number and horizontal gene transfer (HGT) have been the main evolutionary driving forces for adaptability and biodiversity. And the emergence of PAZ domain in AGO proteins is the unique evolutionary event. The analysis of middle domain (MID)-nucleotide contaction shows that either the position of sulfate I bond in Nc_QDE2 or the site of phosphate I bond in Hs_AGO2 represents the 5'-nucleotide binding site of miRNA. Also, H334, T335, and Y336 of Hs_AGO1 can form hydrogen bonds with 3'-overhanging ends of miRNAs and the same situation exists in Hs_AGO2, Hs_AGO3, Hs_AGO4, Dm_AGO1, and Ce_Alg1. Some PIWI domains containing conserved DDH motif have no slicer activity, and post-translational modifications may be associated with the endonucleolytic activities of AGOs. With the numbers of AGO genes increasing and fewer crystal structures available, the evolutionary and functional analyses of AGO proteins can help clarify the molecular mechanism of function diversification in response to environmental changes, and solve major issues including host defense mechanism against virus infection and molecular basis of disease.

Molecular phylogenetic and expression analysis of the complete WRKY transcription factor family in maize.

The WRKY transcription factors function in plant growth and development, and response to the biotic and abiotic stresses. Although many studies have focused on the functional identification of the WRKY transcription factors, much less is known about molecular phylogenetic and global expression analysis of the complete WRKY family in maize. In this study, we identified 136 WRKY proteins coded by 119 genes in the B73 inbred line from the complete genome and named them in an orderly manner. Then, a comprehensive phylogenetic analysis of five species was performed to explore the origin and evolutionary patterns of these WRKY genes, and the result showed that gene duplication is the major driving force for the origin of new groups and subgroups and functional divergence during evolution. Chromosomal location analysis of maize WRKY genes indicated that 20 gene clusters are distributed unevenly in the genome. Microarray-based expression analysis has revealed that 131 WRKY transcripts encoded by 116 genes may participate in the regulation of maize growth and development. Among them, 102 transcripts are stably expressed with a coefficient of variation (CV) value of <15%. The remaining 29 transcripts produced by 25 WRKY genes with the CV value of >15% are further analysed to discover new organ- or tissue-specific genes. In addition, microarray analyses of transcriptional responses to drought stress and fungal infection showed that maize WRKY proteins are involved in stress responses. All these results contribute to a deep probing into the roles of WRKY transcription factors in maize growth and development and stress tolerance.

Transcription factor WRKY70 displays important but no indispensable roles in jasmonate and salicylic acid signaling.

The transcription factor WRKY70 was previously reported to be a common component in salicylic acid (SA) and jasmonate (JA) mediated signal pathways in Arabidopsis. Here, we present that the inactivation of the WRKY70 gene in wrky70-1 mutant does not alter the responses of both JA and SA, and that wrky70 mutation is unable to restore the coi1 mutant in JA responses. However, overexpression of WRKY70 reduces JA responses such as expression of JA-induced genes and JA-inhibitory root growth, and activates expression of SA-inducible PR1. These data indicate that the WRKY70 is important but not indispensable for JA and SA signaling, and that other regulators may display the redundant role with WRKY70 in modulation of JA and SA responses in Arabidopsis. Furthermore, we showed that JA inhibits expression of WRKY70 and PR1 by both COI1-dependent and COI1-independent pathways.

[Intraocular lens power calculation after corneal refractive surgery].

OBJECTIVES: To investigate the effective method for the calculation of intraocular lens power retrospectively from post-LASIK cases. METHODS: It was a retrospective case series. 40 eyes of 28 patients (14 male and 14 Female) had the Phacoemulsification post-LASIK in HongKong Sanitorium & Hospital; the age ranged from 41.00 to 69.00 years ages, (50.68 +/- 6.56) years. LASIK was done from January, 1997 to April, 2005. Phacoemulsification was done from October, 2000 to September, 2005. RESULTS: Average axial length was (28.06 +/- 1.98) mm (rang from 24.28 to 31.96 mm). The initial refraction power (Spherical Equivalent, SE) before LASIK was from -3.13 to -18.00 D, (-10.44 +/- 3.93) D. K value pre-LASIK was 41.40 to 46.90 D, (43.57 +/- 1.47) D. The best corrected visual acuity (BCVA) preLASIK was 20/20 in 19 eyes, 20/25 in 10 eyes, 20/30 in 7 eyes and 20/40 in 4 eyes. The refraction power of 6 months post-LASIK (SE) was -2.83 to +1.25 D, (-0.32 +/- 0.95) D. The refraction power pre-phaco (SE) was -5.75 to +1.13 D, (-2.35 +/- 2.16) D. The calculated K1 (KpreLASIK-RpostLASIK + RpreLASIK) was 27.60 to 40.70 D, (34.62 +/- 3.56) D. The K from the IOLmaster (K2) was 32.39 to 43.53 D, (38.04 +/- 2.45) D. The target refraction of K1 was -3.69 to 0.61 D, (-1.32 +/- 1.00) D, the target refraction of K2 was -3.67 approximately 3.95 D, (-0.60 +/- 1.84) D. There was significant difference between these two target refraction, (t = -2.40, P = 0.02). The refraction power of post-phaco (> 3 months) was -4.50 to +1.75 D, (-1.10 +/- 1.51) D. The BCVA post-Phaco was 20/20 in 20 eyes, 20/25 in 9 eyes, 20/30 in 5 eyes and 20/40 in 6 eyes. CONCLUSIONS: The formula used in the study for the calculation of intraocular lens power is accurate and effective.