ARGONAUTE SUBFAMILY GENES IN THE SMALL BROWN PLANTHOPPER, Laodelphax striatellus (HEMIPTERA: DELPHACIDAE).

Argonaute (AGO) proteins are essential catalytic components of the RNA-induced silencing complex and play central roles in RNA interference. Using a combination of bioinformatics and rapid amplification of cDNA ends (RACE) methods, putative AGO subfamily members, ls-AGO1 and ls-AGO2, were cloned and characterized from the small brown planthopper, Laodelphax striatellus. The open reading frame (ORF) of ls-AGO1 is 2,820 bp long, encoding a putative protein of 939 amino acid residues, and ls-AGO2 contains an ORF of 2,490 bp, encoding 829 amino acid residues. The expected conserved PAZ and PIWI domains, and the conserved Asp-Asp-His (DDH) catalytic triad motif in the PIWI domain were observed in both ls-AGO1 and ls-AGO2. Reverse transcription-qPCR (RT-qPCR) results showed that both ls-AGO1 and ls-AGO2 were expressed in all developmental stages of L. striatellus with highest mRNA abundance in eggs. Expression of ls-AGO1 and ls-AGO2 was significantly decreased in adult insects in response to acquisition of rice black-streaked dwarf virus by second instar nymphs. mRNA expression of ls-AGO1 was significantly downregulated in response to low and high temperatures, but expression of ls-AGO2 was only affected by low temperature. ls-AGO1 and ls-AGO2 were initially downregulated when insects were transferred from rice to maize and to the wild grass Brachypodium distachyon, but expression showed partial or complete recovery 7 days after transfer. These results document that AGO subfamily members of L. striatellus are ubiquitously expressed at different developmental stages and respond to various stresses. Thus, AGO subfamily may act in regulating the stress-response of L. striatellus by controlling related gene expression.

Identification and profiling of conserved and novel microRNAs in Laodelphax striatellus in response to rice black-streaked dwarf virus (RBSDV) infection.

MicroRNAs (miRNAs) are small non-coding endogenous RNA molecules that play important roles in various biological processes. This study examined microRNA profiles of Laodelphax striatellus using the small RNA libraries derived from virus free (VF) and rice black-streaked dwarf virus (RBSDV) infected (RB) insects. A total of 59 mature miRNAs (46 miRNA families) were identified as conserved insect miRNAs in both VF and RB libraries. Among these conserved miRNAs, 24 were derived from the two arms of 12 miRNA precursors. Nine conserved L. striatellus miRNAs were up-regulated and 12 were down-regulated in response to RBSDV infection. In addition, a total of 20 potential novel miRNA candidates were predicted in the VF and RB libraries. The miRNA transcriptome profiles and the identification of L. striatellus miRNAs differentially expressed in response to RBSDV infection will contribute to future studies to elucidate the complex miRNA-mediated regulatory network activated by pathogen challenge in insect vectors.

[Expression of heparanase in kidney of rats with respiratory syncytial virus nephropathy and its relationship with proteinurina].

OBJECTIVE: To explore the role of heparanase in the pathogenesis of respiratory syncytial virus (RSV) nephropathy in rats model. METHODS: Twenty 150-200 g Sprague-Dawley (SD) rats (n = 5 per group) were inoculated with 6 x 10(6) PFU RSV and sacrificed on days 4, 8, 14 and 28 postinoculation (RSV4, RSV8, RSV14 and RSV29). Five SD rats inoculated with Dulbecco's minimum essential medium were served as normal control. The expression levels of heparanase protein and mRNA in the rat renal tissue of each group were determined by immunohistochemical staining and real-time quantitative RT-PCR respectively. The proteinurina was also measured and then the relationship between the expression level of heparanase and the 24-hour urinary protein was studied. RESULTS: The rats with RSV nephropathy exhibited higher proteinuria in comparison with normal rats, and the 24-hour urinary protein level was significantly different between each RSV nephropathy group (RSV14 > RSV8 > RSV28 > RSV4, P < 0.05). Compared with normal control, the rats with RSV nephropathy showed up-regulated expression of heparanase protein in glomeruli. The expression levels of heparanase protein in RSV8 and RSV14 group were higher than those in RSV4 and RSV28 group (P < 0.05). There was a linear positive correlation between the expression level of glomerular heparanase protein and the quantity of 24-hour urinary protein (r = 0.783, P < 0.05). Compared with normal control group, the expression levels of heparanase mRNA in the kidney from RSV4, RSV8, RSV14, and RSV28 group were elevated (RSV14 > RSV8 > RSV4 > RSV28 , P < 0.05). There was a linear positive correlation between the expression level of renal heparanase mRNA and the quantity of 24-hour urinary protein (r = 0.725, P < 0.05). CONCLUSION: The increased expression of heparanase in kidney may be important to the loss of glomerular negative charge in glomerular basement membrane which is involved in the pathogenesis of RSV nephropathy in rats.

[Impact of baseline pulse pressure on new-onset cardio-and cerebrovascular events in diabetic population].

OBJECTIVE: To observe the association between baseline pulse pressure (PP) level and new-onset cardio-cerebrovascular events in diabetic population. METHODS: Physical examination data between July 2006 to October 2007 from a total of 101 510 employees of Kailuan Group were reviewed, 8306 subjects with a fasting plasma glucose level of ≥ 7.0 mmol/L or with confirmed diabetes diagnosis and were enrolled in this prospective cohort study. Subjects were followed up for 38-53 (48.1 ± 3.1) months and the cardio-cerebrovascular events were obtained every six months, association between baseline PP and new-onset cardio-cerebrovascular events in the diabetic population were analyzed. RESULTS: (1) Incidences of total cardio-cerebrovascular events in the PP groups were 3.4%, 2.8%, 4.5%, 6.4%, respectively. Incidences of cerebral infarction events and myocardial infarction were 2.1%, 1.6%, 2.9%, 3.9% and 1.1%, 0.7%, 1.0%, 1.7%, respectively. (2) Multivariate Cox's proportional hazards regression analysis indicated that baseline PP group was the risk factor for total cardio-cerebrovascular events, cerebral infarction events and myocardial infarction, and the risk for all the events of the PP ≥ 60 mm Hg (1 mm Hg = 0.133 kPa) group was increasing. The values of RR(95%CI) were 1.88 (95%CI 1.34-2.65, P < 0.01), 1.92 (95%CI 1.23-2.99, P < 0.01) and 1.52 (95%CI 0.82-2.81, P > 0.05) after adjust the other factors.(3) In line with increasing level of baseline PP, age, BMI, SBP, DBP, HDL-C, and hs-CRP levels significantly increased in this diabetic population (P < 0.01 or P < 0.05). CONCLUSION: The level of high baseline PP is a risk factor for new-onset cardio-cerebrovascular events in diabetic population.