Mutation of the rice AN1-type zinc-finger protein gene ASL4 causes chloroplast development defects and seedling lethality

Plant zinc-finger proteins play a crucial role in biosynthesis and plant development. However, it is not known whether certain zinc-finger proteins play a role in rice chloroplast development. In this study, a novel rice zinc-finger protein mutant asl4 (albino seedling lethality4), which exhibits an albino lethal phenotype at the seedling stage, was used. Chlorophyll fluorescence analysis and TEM were used to investigate features of the asl4 mutant. The genetic behaviour and function of ASL4 gene were then analysed thorough map-based cloning, transgenic complement and subcellular localization. The albino lethal phenotype was caused by a single nucleotide (G*) deletion mutation on the exon of the ASL4 (LOC_Os09g21710) gene. The ASL4 gene encoded a novel zinc-finger protein containing two ZnF-AN1 domains, which was localized to the nucleocytoplasm. The ASL4 transcripts were highly expressed in all leaves but relatively less in other tissues, suggesting its tissue-specific expression. The transcript levels of associated genes for Chl biosynthesis, photosynthesis and chloroplast development were severely suppressed in asl4 mutants. In conclusion, the absence of ASL4 function caused a defect in chloroplast development and seedling lethality. This is the first published report on the importance of the ZnF-AN1 type zinc-finger protein gene in chloroplast development in rice.

Effects of haem oxygenase-1 expression on oxidative injury and biological behaviours of rat dermal fibroblasts

OBJECTIVE

This study investigated the effects of high haem oxygenase-1 (HO-1) expression on oxidative injury and the biological behaviours of rat dermal fibroblasts, under high glucose conditions.

METHOD

Rat dermal fibroblasts were cultured in normal glucose (1.0g/l), high glucose (4.5g/l) or haemin (5μm). A bilirubin kit, real-time polymerase chain reaction (RT-PCR) and Western blotting measured the protease activity, mRNA, and protein levels of HO-1, respectively. An enzyme-linked immunosorbent assay (ELISA) kit measured media levels of 8-hydroxydeoxyguanosine (8-OHdG), reactive oxygen species (ROS) and collagen (hydroxyproline) secretion. Cell proliferation was measured using flow cytometry. Cell apoptosis was measured using Hoechst 33258 staining and flow cytometry. The transwell method and scratch test evaluated cell migration.

RESULTS

HO-1 expression exhibited a time-dependent change that was lowest in the high glucose (HG) group at 96 hours compared with the normal glucose (NG) group. In the HG group, the 8-OHdG, ROS and cell apoptosis were increased, and collagen secretion, cell proliferation and cell migration (horizontal and vertical) were decreased compared with the NG group at 96 hours. Haemin treatment sustained high HO-1 expression for at least 96 hours, and the cells exhibited decreased 8-OHdG and ROS, increased collagen synthesis, improved proliferation and migration ability, and decreased apoptosis in the NG and haemin (NH) group/HG and haemin (HH) group compared with the NG/HG groups. These cells recovered from oxidative injury and biological behaviours dysfunction.

CONCLUSION

Haemin induces HO-1 expression in fibroblasts and it may influence the oxidative injury and biological behaviours of fibroblasts. These findings suggest that HO-1 may accelerate the healing of diabetic wounds via alleviation of oxidative injury and improvement of biological behaviours of fibroblasts.

Glycemic load is associated with diabetes and prediabetes among middle-aged and elderly adults in Guangzhou, China

BACKGROUND AND OBJECTIVES

Previous studies have obtained conflicting findings regarding the possible associations between glycemic load (GL) indices and diabetes. In the present study, we examined cross-sectional associations between several GL indices, including the total dietary GL, the energy-adjusted GL, and the prevalence of abnormal glucose metabolism, including prediabetes and diabetes.

METHODS AND STUDY DESIGN

This study was conducted in Guangzhou, China from July 2011 to December 2011. It included 2,022 participants (602 men and 1,420 women), between 45 and 75 years of age. The prevalence of abnormal glucose metabolism was compared across the quartiles of GL indices to discover any potential linear correlations. Stratified analysis was conducted according to the body mass index (BMI) and waist circumference (WC) measurements.

RESULTS

Energy-adjusted GL was positively associated with the prevalence of diabetes and the multivariable-adjusted estimate of the OR comparing the highest versus the lowest quartile was 2.50 (95% CI, 1.49-4.19). For the stratified analysis by sex, BMI or WC, similar associations were observed. For the overweight and obese (BMI ≥24.0 kg/m2) or centrally obese (WC ≥85 cm for men or ≥80 cm for women) participants, compared to participants in the lowest quartile of energy-adjusted GL, those in the highest quartile showed an increased risk of abnormal glucose metabolism. The OR estimates were 2.25 (95% CI: 1.45-3.52) and 1.54 (95% CI: 1.06-2.25), respectively.

CONCLUSIONS

High dietary energy-adjusted GL is associated with the prevalence of diabetes as well as abnormal glucose metabolism among middle-aged and elderly adults.

A greater glycemic load reduction was associated with a lower diabetes risk in pre-diabetic patients who consume a high glycemic load diet

Few prospective studies evaluating the association between dietary glycemic load (GL) and diabetes have accounted for changes in GL. However, the diet of patients could be modified in response to an awareness of pre-diabetes. The aim of this study was to examine the longitudinal associations between changes in GL and the incidence of diabetes among pre-diabetic patients. We hypothesized that subjects with low and high baseline GL would show different correlations with diabetes. A total of 493 pre-diabetic patients (142 men and 351 women) between 40 and 79 years of age were included in this study. Dietary records and oral glucose tolerance tests were conducted every year. The participants were divided into low- and high-GL groups based on baseline GL. During a median 4 years of follow-up, 108 incident cases of diabetes were identified. Among participants with a high baseline GL, the incidence of diabetes increased with decreasing GL reduction, and the multivariate-adjusted HR (95% CI) was 2.34 (1.27-4.29) when comparing the lowest to the highest tertiles; however, among those with a low baseline GL, no significant association was observed. Regardless of baseline GL status, the incidence of diabetes was higher in individuals with a high follow-up GL than in those with a low follow-up GL, and the multivariate-adjusted HR (95% CI) was 1.64 (1.09-2.45). In conclusion, a greater GL reduction was associated with a lower diabetes risk in pre-diabetic patients with a high dietary GL. In patients with pre-diabetes and a low dietary GL, further reductions in GL did not show any additional effects.

[Diagnostic criteria for late-onset hypogonadism: A preliminary study]

OBJECTIVE

To determine the stability of androgen indexes by analyzing the relationship of androgen indexes with the results of late-onset hypogonadism (LOH) questionnaire investigations, and offer some reference for the application of the diagnostic criteria for LOH released by The Chinese Society of Andrology in 2009.

METHODS

This study included 1 003 males aged 40 years or older who had accomplished the questionnaires of Androgen Deficiency in Aging Males (ADAM), Aging Males' Symptoms Scale (AMS), and International Index of Erectile Function-5 (IIEF-5). We evaluated the correlation of androgen indexes with the results of the questionnaire investigation, repeated the examination of androgen indexes for the subjects with total testosterone (TT) ≤11.5 nmol/L after an average of 1.5 years, and analyzed the factors inducing changes of androgen indexes.

RESULTS

Free testosterone index (FTI) ≤ 0.42 (OR, 1.369) and calculated free testosterone (cFT) ≤ 0.3 nmol/L (OR, 1.302) were considered as the risk factors of LOH in AMS, and so were testosterone secretion index (TSI) ≤ 2.8 nmol/IU (OR, 1.679) and cFT ≤ 0.3 nmol/L (OR, 1.371) in IIEF-5. Paired t-test on the results of the examination performed twice showed significant differences in the levels of TT, TSI, cFT, and FT (P<0.05).

CONCLUSIONS

Decreased testosterone may cause the diversity of LOH symptoms and hence the fluctuation of androgens. Therefore, the diagnosis of LOH depends on androgen indexes, varied symptoms in the questionnaires, and relief of the symptoms after testosterone therapy.

[Association of serum testosterone with atherosclerosis in middle-aged and elderly men]

OBJECTIVE

To investigate the association between the level of serum testosterone and atherosclerosis in middle-aged and elderly men.

METHODS

We conducted a population-based study of 413 males aged 40-75 years in a community in Guangzhou. We obtained the sociodemographic characteristics, clinical data, physical measurements, and laboratory results of sex hormones, blood glucose, and blood lipid of the subjects. We also measured the carotid intima media thickness (CIMT) by color Doppler ultrasonography.

RESULTS

The subjects were divided into a carotid atherosclerosis (CAS) group (CIMT ≥ 0.9 mm) and a non-CAS group (CIMT < 0.9 mm). The medians of free testosterone (FT) were 57.41 and 59.72 pmol/L in the CAS and non-CAS groups, respectively (P = 0.005), and no significant difference was found between the two groups in total testosterone (TT). The levels of serum FT and TT were negatively correlated to CIMT, with Spearman's rank correlation coefficients of -0.126 (P = 0.011) and -0.188 (P < 0.001), respectively. The incidence rates of CAS were 23.30, 13.46, 17.48, and 7.77% in the Q1, Q2, Q3, and Q4 groups, respectively according to the quartile of FT (P for trend = 0.008) and 17.48, 18.27, 16.50, and 9.71% respectively according to the quartile of TT (P for trend = 0.116). Based on the quartile of FT and after adjustment for age, waist circumference, systolic blood pressure, and HbAlc, the risk of CAS was significantly increased in the Q1 group as compared with Q4 (OR = 2.491, 95% CI 1.01-6.149), but no statistically significant differences were observed according to the quartile of TT.

CONCLUSION

A low serum FT level may be a risk factor of atherosclerosis in Chinese men aged 40 years or older.

Changes in biological behaviors of rat dermal fibroblasts induced by high expression of MMP9

BACKGROUND

The high level of matrix metalloproteinase 9 (MMP9) is thought to slow down the healing of diabetic foot ulcers. Whether it can influence the biological behaviors of skin fibroblasts and affect wound healing is still unclear. The present study aimed to observe changes in the biological behaviors of rat dermal fibroblasts induced by high expression of MMP9 and to clarify the possible mechanisms of wound healing for diabetic foot.

METHODS

A cell model of skin fibroblast with high expression of MMP9 was established by co-culture of high glucose (22.0 mmol/L) and homocysteine (100 μmol/L). A control group was incubated with normal glucose (5.5 mmol/L). Realtime PCR, ELISA and gelatin zymography were used to detect the MMP9 mRNA, protein expression and activity of MMP9. Flow cytometry, CCK-8, ELISA assay, scratch test and transwell were used to detect cell proliferation, viability, collagen (hydroxyproline) secretion, horizontal migration and vertical migration of cells. The data were expressed as mean±SD. P value less than 0.05 was considered statistically significant.

RESULTS

The expression of MMP9 mRNA, protein levels and the activity of MMP9 were much higher in the high MMP9 group than in the control group (7.05±1.02 vs. 1.00±0.00, 206.9±33.6 pg/mL vs. 40.4±5.9 pg/mL, and 1.47±0.13 vs. 0.57±0.12, respectively, P<0.01). The proportion of S-phase cells, proliferation index, cell viability, collagen (hydroxyproline) secretion, horizontal migration rate and the number of vertical migration cells were lower in the high MMP9 group than in the control group (P<0.01).

CONCLUSION

Fibroblasts with a high expression of MMP9 decreased proliferation, activity, secretion and migration of collagens, suggesting that MMP9 may inhibit the biological behaviors of fibroblasts.

Cationic star-shaped polymer as an siRNA carrier for reducing MMP-9 expression in skin fibroblast cells and promoting wound healing in diabetic rats

Background

Excessive expression of matrix metalloproteinase-9 (MMP-9) is deleterious to the cutaneous wound-healing process in the context of diabetes. The aim of the present study was to explore whether a cationic star-shaped polymer consisting of β-cyclodextrin (β-CD) core and poly(amidoamine) dendron arms (β-CD-[D₃]₇) could be used as the gene carrier of small interfering RNA (siRNA) to reduce MMP-9 expression for enhanced diabetic wound healing.

Methods

The cytotoxicity of β-CD-(D₃)₇ was investigated by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MMT) method in the rat CRL1213 skin fibroblast cell line. The transfection efficiency of β-CD-(D₃)₇/MMP-9-small interfering RNA (siRNA) complexes was determined by confocal microscopy and flow cytometry. Quantitative real time (RT) polymerase chain reaction was performed to measure the gene expression of MMP-9 after the transfection by β-CD-(D₃)₇/MMP-9-siRNA complexes. The β-CD-(D₃)₇/MMP-9-siRNA complexes were injected on the wounds of streptozocin-induced diabetic rats. Wound closure was measured on days 4 and 7 post-wounding.

Results

β-CD-(D₃)₇ exhibited low cytotoxicity in fibroblast cells, and easily formed the complexes with MMP-9-siRNA. The β-CD-(D₃)₇/MMP-9-siRNA complexes were readily taken up by fibroblast cells, resulting in the downregulation of MMP-9 gene expression (P<0.01). Animal experiments revealed that the treatment by β-CD-(D₃)₇/MMP-9-siRNA complexes enhanced wound closure in diabetic rats on day 7 post-wounding (P<0.05).

Conclusion

β-CD-(D₃)₇ may be used as an efficient carrier for the delivery of MMP-9-siRNA to reduce MMP-9 expression in skin fibroblast cells and promote wound healing in diabetic rats.

[Effects of matrix metallopeptidase 9 on the proliferation, apoptosis, type I and III procollagen synthesis of rat dermal fibroblasts]

OBJECTIVE

To explore the effects of matrix metallopeptidase 9 (MMP-9) on the proliferation, apoptosis, type I and III procollagen synthesis of rat dermal fibroblasts.

METHODS

Lipopolysaccharide (LPS) at 0.1 and 1.0 µg/ml was used to stimulate fibroblasts to up-regulate the expression of MMP-9 for 18 and 48 h. And then RNA interference was employed to inhibit the high expression of MMP-9. Cell proliferation was tested by CCK-8, cell apoptosis by flow cytometry and type I and III procollagen expressions by quantitative reverse transcriptase PCR (qRT-PCR).

RESULTS

The MMP-9 expression of fibroblasts increased after the stimulation of LPS. And the 1.0 µg/ml LPS stimulation of 48 hours was 14.25 times of mRNA expression and 2.31 times of protein expression versus that of the normal group (both P < 0.05). The RNA interference obviously inhibited the high expression of MMP-9. The mRNA expression was 1/8 and protein expression 1/3 (both P < 0.05) as compared with the control group. Cell proliferation decreased with the rising expression of MMP-9 to some extent [(1.08 ± 0.08) vs (1.18 ± 0.09), P < 0.05] and improved after the inhibition of high expression of MMP-9 [(1.78 ± 0.17) vs (1.53 ± 0.15), P < 0.01]. There was no change of apoptosis accompanied with high expression of MMP-9 (P > 0.05). Apoptosis decreased after the inhibition of high expression of MMP-9 for 48 hours (3.53% ± 0.22% vs 4.47% ± 0.46%, P < 0.05). The synthesis of type I procollagen was the same no matter up-regulation or down-regulation of MMP-9 expression (P > 0.05). As the expression of MMP-9 increased, the synthesis of type III procollagen decreased (P < 0.01), but not increased by 1.02 folds after the inhibited expression of MMP-9 (P > 0.05).

CONCLUSION

MMP-9 can affect the biological behaviors of rat dermal fibroblasts.

Optimizing electromagnetic enhancement of flexible nano-imprinted hexagonally patterned surface-enhanced Raman scattering substrates

The production of inexpensive, large-scale, uniform substrates for surface-enhanced Raman scattering (SERS) is a key to popularize its usage in chemical and biological detection. We demonstrate a flexible nano-imprinted hexagonally patterned SERS-active substrate. Its electromagnetic enhancement factor was optimized by the thickness adjustment of its silver over-coated film. The experimental data show a good correspondence with the theoretical prediction. Such substrate was shown to exhibit high uniformity and reproducibility with a variation of less than 2%, offering a potential of greatly exploiting such substrate in infield biocide monitoring.

Enhancing intensity of emitted light from a ring by incorporating a circular groove

We fabricated a ring containing a single circular groove (RCG) on silver film and which was supported on a glass substrate. We found that by changing the mean radius of the circular groove, the light intensity emitted from the RCG can be modulated by using the scattering light from the circular groove. In addition, we also fabricated circular grooves with the same depth but of different widths so that we could examine the scattering light behavior of the grooves. Herein, we propose a theoretical model which takes into account the amplitude modulation of the cylindrical waves. Our results showed that our proposed model agreed well with the experimental results.

Similarities and differences for light-induced surface plasmons in one- and two-dimensional symmetrical metallic nanostructures

Two types of double-sided nanostructure, one possessing a slit aperture with parallel grooves and the other possessing a circular aperture with concentric grooves, were fabricated to examine the similarities and differences of their diffraction behavior in one-dimensional (1-D) and two-dimensional (2-D) nanostructures. Based on the projection-slice theory, we conjecture that the surface plasmons in these two different nano-scale grooves possess similar modes. A localized surface plasmon (LSP) was used to examine the transmission characteristics induced by the apertures. The transmission characteristics of the slitted nanostructure and the circular nanostructure aperture were then measured. We coupled the transmission spectra measured from these two apertures with a 1-D parallel groove transmission curve simulated by a 1-D rigorous coupled wave analysis. Measured spectra results show reasonable agreement with the simulated data. We propose that the apparent blueshift observed in the peak frequency of a 2-D nanostructure is due to the difference in the shape of the aperture and the spot transmission characteristics of 1-D and 2-D systems as induced by a LSP.

Beaming light from a subwavelength metal slit surrounded by dielectric surface gratings

In this article, we demonstrate that a subwavelength metal slit surrounded by dielectric surface gratings possesses a directional beaming effect. We propose a surface plasmon diffraction scheme to explain the three kinds of beaming conditions. The numerical simulations of the illustrative structures undertaken used a Finite Difference Time Domain (FDTD) Method and a Rigorous Coupled Wave Analysis (RCWA) Method. Our simulations were found to be consistent and in agreement with the experimental results. In comparison with other metal structures, we find that dielectric metal structures offer better performance as well as the advantage of being able to be efficiently mass produced for large volume industrial applications.

Simulation and fabrication of subwavelength structures for a nanometer feature enabling lens-less laser writers

A set-up was proposed to propagate submicrometer light beams without resorting to the conventional approach of using a lens. The main target was to develop a method of either by passing or circumventing the diffraction limit to develop a new optical head for a laser writer system with submicrometer resolution. Starting from using surface plasma theory to explain the mechanism of extraordinary transmission phenomenon, we move to discuss the fabrication processes for free-standing metal films and the corresponding transmission light beam images in the far field. A finite difference time domain (FDTD) method was adopted to simulate the electromagnetic field distribution of transmission light beams from the near field to the far field. The experimental results confirm that surface structures on the incident side of incoming light beams can excite surface plasma and enhance the throughput energy of transmission light beams. In addition, we also established that surface structures on the exit side can suppress the diffraction effect and make transmission light beams directional. The experimental and simulation results were found to agree well with each other, which validates the effectiveness of the FDTD simulation approach. As a free-standing film was too fragile to be of practical use, a proposition to develop a substrate-based nanostructured film to ease the construction of an optical head for a laser writer was developed.