Multiscale physiological responses to nitrogen supplementation of maize hybrids

Maize (Zea mays) production systems are heavily reliant on the provision of managed inputs such as fertilizers to maximize growth and yield. Hence, the effective use of nitrogen (N) fertilizer is crucial to minimize the associated financial and environmental costs, as well as maximize yield. However, how to effectively utilize N inputs for increased grain yields remains a substantial challenge for maize growers that requires a deeper understanding of the underlying physiological responses to N fertilizer application. We report a multiscale investigation of five field-grown maize hybrids under low or high N supplementation regimes that includes the quantification of phenolic and prenyl-lipid compounds, cellular ultrastructural features, and gene expression traits at three developmental stages of growth. Our results reveal that maize perceives the lack of supplemented N as a stress and, when provided with additional N, will prolong vegetative growth. However, the manifestation of the stress and responses to N supplementation are highly hybrid-specific. Eight genes were differentially expressed in leaves in response to N supplementation in all tested hybrids and at all developmental stages. These genes represent potential biomarkers of N status and include two isoforms of Thiamine Thiazole Synthase involved in vitamin B1 biosynthesis. Our results uncover a detailed view of the physiological responses of maize hybrids to N supplementation in field conditions that provides insight into the interactions between management practices and the genetic diversity within maize.

Genome-Wide Identification and Transcriptional Analysis of AP2/ERF Gene Family in Pearl Millet (Pennisetum glaucum)

The apetala2/ethylene response factor (AP2/ERF) gene family plays a crucial role in regulating plant growth and development and responding to different abiotic stresses (e.g., drought, heat, cold, and salinity). However, the knowledge of the ERF family in pearl millet remains limited. Here, a total of 167 high-confidence PgERF genes are identified and divided into five subgroups based on gene-conserved structure and phylogenetic analysis. Forty-one pairs of segmental duplication are found using collinear analysis. Nucleotide substitution analysis reveals these duplicated pairs are under positive purification, indicating they are actively responding to natural selection. Comprehensive transcriptomic analysis reveals that PgERF genesare preferentially expressed in the imbibed seeds and stem (tilling stage) and respond to heat, drought, and salt stress. Prediction of the cis-regulatory element by the PlantCARE program indicates that PgERF genes are involved in responses to environmental stimuli. Using reverse transcription quantitative real-time PCR (RT-qPCR), expression profiles of eleven selected PgERF genes are monitored in various tissues and during different abiotic stresses. Transcript levels of each PgERF gene exhibit significant changes during stress treatments. Notably, the PgERF7 gene is the only candidate that can be induced by all adverse conditions. Furthermore, four PgERF genes (i.e., PgERF22, PgERF37, PgERF88, and PgERF155) are shown to be involved in the ABA-dependent signaling pathway. These results provide useful bioinformatic and transcriptional information for understanding the roles of the pearl millet ERF gene family in adaptation to climate change.

REGULATOR OF FLOWERING AND STRESS manipulates stomatal density and size in Brachypodium

Stomata are crucial for gas exchange and water evaporation, and environmental stimuli influence their density (SD) and size (SS). Although genes and mechanisms underlying stomatal development have been elucidated, stress-responsive regulators of SD and SS are less well-known. Previous studies have shown that the stress-inducible Brachypodium RFS (REGULATOR OF FLOWERING AND STRESS, BdRFS) gene affects heading time and enhances drought tolerance by reducing leaf water loss. Here, we report that overexpression lines (OXs) of BdRFS have reduced SD and increased SS, regardless of soil water status. Furthermore, biomass and plant water content of OXs were significantly increased compared to wild type. CRISPR/Cas9-mediated BdRFS knockout mutant (KO) exhibited the opposite stomatal characteristics and biomass changes. Reverse transcription-quantitative polymerase chain reaction analysis revealed that expression of BdICE1 was reversely altered in OXs and KO, pointing to a potential cause for the observed changes in stomatal phenotypes. Stomatal and transcriptional changes were not observed in the Arabidopsis rfs double mutant. Taken together, RFS is a novel regulator of SD and SS and is a promising candidate for genetic engineering of climate-resilient crops.

A stress-inducible protein regulates drought tolerance and flowering time in Brachypodium and Arabidopsis

To cope with environmental stresses and ensure maximal reproductive success, plants have developed strategies to adjust the timing of their transition to reproductive growth. This has a substantial impact on the stress resilience of crops and ultimately on agricultural productivity. Here, we report a previously uncharacterized, plant-specific gene family designated as Regulator of Flowering and Stress (RFS). Overexpression of the BdRFS gene in Brachypodium distachyon delayed flowering, increased biomass accumulation, and promoted drought tolerance, whereas clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated knockout mutants exhibited opposite phenotypes. A double T-DNA insertional mutant in the two Arabidopsis (Arabidopsis thaliana) homologs replicated the effects on flowering and water deprivation seen in the B. distachyon CRISPR knockout lines, highlighting the functional conservation of the family between monocots and dicots. Lipid analysis of B. distachyon and Arabidopsis revealed that digalactosyldiacylglycerol (DGDG) and phosphatidylcholine (PC) contents were significantly, and reciprocally, altered in overexpressor and knockout mutants. Importantly, alteration of C16:0-containing PC, a Flowering Locus T-interacting lipid, associated with flowering phenotype, with elevated levels corresponding to earlier flowering. Co-immunoprecipitation analysis suggested that BdRFS interacts with phospholipase Dα1 as well as several other abscisic acid-related proteins. Furthermore, reduction of C18:3 fatty acids in DGDG corresponded with reduced jasmonic acid metabolites in CRISPR mutants. Collectively, we suggest that stress-inducible RFS proteins represent a regulatory component of lipid metabolism that impacts several agronomic traits of biotechnological importance.

A novel calmodulin-interacting Domain of Unknown Function 506 protein represses root hair elongation in Arabidopsis

Domain of Unknown Function 506 proteins are ubiquitous in plants. The phosphorus (P) stress-inducible REPRESSOR OF EXCESSIVE ROOT HAIR GROWTH1 (AtRXR1) gene encodes the first characterized DUF506. AtRXR1 inhibits root hair elongation by interacting with RabD2c GTPase. However, functions of other P-responsive DUF506 genes are still missing. Here, we selected two additional P-inducible DUF506 genes for further investigation. The expression of both genes was induced by auxin. Under P-stress, At3g07350 gene expressed ubiquitously in seedlings, whereas At1g62420 (AtRXR3) expression was strongest in roots. AtRXR3 overexpressors and knockouts had shorter and longer root hairs, respectively. A functional AtRXR3-green fluorescent protein fusion localized to root epidermal cells. Chromatin immunoprecipitation and quantitative reverse-transcriptase-polymerase chain reaction revealed that AtRXR3 was transcriptionally activated by RSL4. Bimolecular fluorescence complementation and calmodulin (CaM)-binding assays showed that AtRXR3 interacted with CaM in the presence of Ca²⁺ . Moreover, cytosolic Ca²⁺ ([Ca²⁺ ]_cyt ) oscillations in root hairs of rxr3 mutants exhibited elevated frequencies and dampened amplitudes compared to those of wild type. Thus, AtRXR3 is another DUF506 protein that attenuates P-limitation-induced root hair growth through mechanisms that involve RSL4 and interaction with CaM to modulate tip-focused [Ca²⁺ ]_cyt oscillations.

Validation of the hepatocellular carcinoma early detection screening algorithm Doylestown and aMAP in a cohort of Chinese with cirrhosis

Background

Previous studies have developed some blood‐based biomarker algorithms such as the Doylestown algorithm and aMAP score to improve the detection of Hepatocellular carcinoma (HCC). However, no one has studied the application of the Doylestown algorithm in the Chinese. Meanwhile, which of these two screening models is more suitable for people with liver cirrhosis remains to be investigated.

Methods

In this study, HCC surveillance was performed by radiographic imaging and testing for tumor markers every 6 months from August 21, 2018, to January 12, 2021. We conducted a retrospective study of 742 liver cirrhosis patients, and among them, 20 developed HCC during follow‐up. Samples from these patients at three follow‐up time points were tested to evaluate alpha‐fetoprotein (AFP), the Doylestown algorithm, and aMAP score.

Results

Overall, 521 liver cirrhosis patients underwent semiannual longitudinal follow‐up three times. Five patients were diagnosed with HCC within 0–6 months of the third follow‐up. We found that for these liver cirrhosis patients, the Doylestown algorithm had the highest accuracy for HCC detection, with areas under the receiver operating characteristic curve (AUCs) of 0.763, 0.801, and 0.867 for follow‐ups 1–3, respectively. Compared with AFP at 20 ng/ml, the Doylestown algorithm increased biomarker performance by 7.4%, 21%, and 13% for follow‐ups 1–3, respectively.

Conclusions

Our findings show that the Doylestown algorithm performance appeared to be optimal for HCC early screening in the Chinese cirrhotic population when compared with the aMAP score and AFP at 20 ng/ml.

A phosphorus-limitation induced, functionally conserved DUF506 protein is a repressor of root hair elongation in plants

Root hairs (RHs) function in nutrient and water acquisition, root metabolite exudation, soil anchorage and plant-microbe interactions. Longer or more abundant RHs are potential breeding traits for developing crops that are more resource-use efficient and can improve soil health. While many genes are known to promote RH elongation, relatively little is known about genes and mechanisms that constrain RH growth. Here we demonstrate that a DOMAIN OF UNKNOWN FUNCTION 506 (DUF506) protein, AT3G25240, negatively regulates Arabidopsis thaliana RH growth. The AT3G25240 gene is strongly and specifically induced during phosphorus (P)-limitation. Mutants of this gene, which we call REPRESSOR OF EXCESSIVE ROOT HAIR ELONGATION 1 (RXR1), have much longer RHs, higher phosphate content and seedling biomass, while overexpression of the gene exhibits opposite phenotypes. Co-immunoprecipitation, pull-down and bimolecular fluorescence complementation (BiFC) analyses reveal that RXR1 physically interacts with a RabD2c GTPase in nucleus, and a rabd2c mutant phenocopies the rxr1 mutant. Furthermore, N-terminal variable region of RXR1 is crucial for inhibiting RH growth. Overexpression of a Brachypodium distachyon RXR1 homolog results in repression of RH elongation in Brachypodium. Taken together, our results reveal a novel DUF506-GTPase module with a prominent role in repression of plant RH elongation especially under P stress.

Genome-Wide Identification and Transcriptional Analysis of Arabidopsis DUF506 Gene Family

The Domain of unknown function 506 (DUF506) family, which belongs to the PD-(D/E)XK nuclease superfamily, has not been functionally characterized. In this study, 266 DUF506 domain-containing genes were identified from algae, mosses, and land plants showing their wide occurrence in photosynthetic organisms. Bioinformatics analysis identified 211 high-confidence DUF506 genes across 17 representative land plant species. Phylogenetic modeling classified three groups of plant DUF506 genes that suggested functional preservation among the groups based on conserved gene structure and motifs. Gene duplication and Ka/Ks evolutionary rates revealed that DUF506 genes are under purifying positive selection pressure. Subcellular protein localization analysis revealed that DUF506 proteins were present in different organelles. Transcript analyses showed that 13 of the Arabidopsis DUF506 genes are ubiquitously expressed in various tissues and respond to different abiotic stresses and ABA treatment. Protein-protein interaction network analysis using the STRING-DB, AtPIN (Arabidopsis thaliana Protein Interaction Network), and AI-1 (Arabidopsis Interactome-1) tools indicated that AtDUF506s potentially interact with iron-deficiency response proteins, salt-inducible transcription factors, or calcium sensors (calmodulins), implying that DUF506 genes have distinct biological functions including responses to environmental stimuli, nutrient-deficiencies, and participate in Ca(2+) signaling. Current results provide insightful information regarding the molecular features of the DUF506 family in plants, to support further functional characterizations.

Metabolomic evaluation of serum metabolites of geese reared at different stocking densities

1. Stocking density is an issue for poultry production. High stocking density can impact biochemical parameters, production, and reproductive performance; however, information regarding the effects of stocking density on serum metabolites in geese is limited.2. Twenty-day-old, Sanhua male geese (n = 240) were allocated to one of two experimental groups for 50 days. One group was housed under a low stocking density (LSD; two birds per m²) and one under a high stocking density (HSD; five birds per m²). Body weight and feed intake were recorded every 10 d. Eight serum samples per group were used for metabonomic analysis by liquid chromatography-mass spectrometry.3. Stocking density did not affect the spleen, liver, thymus, or bursa of Fabricius weights after 50 d. Feed intake and body weight was significantly lower in geese from the HSD group versus the LSD group (P < 0.05). Thirty-six differential serum metabolites were identified (P < 0.05), indicating altered amino acid, carbohydrate, lipid and vitamin cofactor metabolism.4. The results demonstrated that high-density stocking impacts geese, and provides insights into the mechanisms underlying the adverse health effects associated with HSD.

Metabolomic profiling of goslings with visceral gout reveals a distinct metabolic signature

1.The objective of the experiment was to analyse serum profiles of goslings with visceral gout and compare them with those of healthy individuals to identify differentially-abundant metabolites as potential biomarkers. 2.Untargeted gas chromatography and time-of-flight mass spectrometry (GC-TOF-MS) metabolomic profiling was used to compare the serum metabolome of 15 goslings (Anser cygnoides) with gout and 15 healthy goslings (control). 3.Goslings with gout had a metabolic profile distinct from that of the controls, with 45 metabolite levels differing significantly (VIP > 1; P < 0.05) between both groups. Nine metabolites (hydrocortisone, glucose, trans-4-hydroxy-L-proline, galactose, 2-deoxy-D-galactose, beta-mannosylglycerate, d-glucoheptose, zymosterol, and hypoxanthine) were selected through receiver operating characteristics (ROC) analysis (area under curve (AUC) score ≥0.85) as potential biomarkers. Pathway analysis revealed that metabolites with differing levels were mainly involved in galactose, arginine and proline and purine metabolisms. 4.These results provided new insights into the pathogenesis of gout. Increased xanthine and hypoxanthine with decreased hydrocortisone provide promising biomarkers for gosling gout diagnosis. The findings suggested that hepatic metabolic disorders frequently occur in the development of avian gout.

The clinical significance of serum chitinase 3-like 1 in hepatitis B-related chronic liver diseases

Aim

In the present study, we purposed to determine serum chitinase 3‐like 1 (CHI3L1) expression characteristics in chronic liver diseases monoinfected with hepatitis B virus and analyze its diagnostic value in liver fibrosis.

Methods

A total of 467 chronic hepatitis B (CHB) patients, 312 liver cirrhosis (LC) patients, and 104 hepatocellular carcinoma (HCC) patients at our institution were enrolled, and clinical indicators were analyzed.

Results

Our data have shown that the expression level of serum CHI3L1 was steadily increased from CHB to LC to HCC (P < .001). Serum CHI3L1 expression levels were positively associated with liver stiffness measurement (LSM), fibrosis‐4 (FIB‐4) index, aspartate aminotransferase‐to‐platelet ratio index (APRI), and HCC stage. The receiver operating characteristic (ROC) curve proved that serum CHI3L1 was superior to other noninvasive methods (LSM, FIB‐4, and APRI) with an area under the ROC curve (AUC) of 0.97 in diagnosing significant fibrosis.

Conclusions

Serum CHI3L1 harbors significant clinical value in chronic liver diseases infected with hepatitis B virus, especially in the diagnosis of fibrosis.

Comparison of microRNAs in adipose and muscle tissue from seven indigenous Chinese breeds and Yorkshire pigs

Elucidation of the pig microRNAome is essential for interpreting functional elements of the genome and understanding the genetic architecture of complex traits. Here, we extracted small RNAs from skeletal muscle and adipose tissue, and we compared their expression levels between one Western breed (Yorkshire) and seven indigenous Chinese breeds. We detected the expression of 172 known porcine microRNAs (miRNAs) and 181 novel miRNAs. Differential expression analysis found 92 and 12 differentially expressed miRNAs in adipose and muscle tissue respectively. We found that different Chinese breeds shared common directional miRNA expression changes compared to Yorkshire pigs. Some miRNAs differentially expressed across multiple Chinese breeds, including ssc-miR-129-5p, ssc-miR-30 and ssc-miR-150, are involved in adipose tissue function. Functional enrichment analysis revealed that the target genes of the differentially expressed miRNAs are associated mainly with signaling pathways rather than metabolic and biosynthetic processes. The miRNA-target gene and miRNA-phenotypic traits networks identified many hub miRNAs that regulate a large number of target genes or phenotypic traits. Specifically, we found that intramuscular fat content is regulated by the greatest number of miRNAs in muscle tissue. This study provides valuable new candidate miRNAs that will aid in the improvement of meat quality and production.

Expression of IL-17A, E, and F and their receptors in non-small-cell lung cancer

Lung cancer is the leading cause of cancer-related morbidity and mortality worldwide. Interaction of nascent or established lung tumour cells with various cytokines and infiltrating immune cells has been implicated in lung cancer pathogenesis. In this study, we systematically analysed immunoreactivity for IL-17A, IL-17E and IL-17F and their relevant receptors in the lung sections from non-small cell lung cancer (NSCLC) and normal control. Immunoreactivity for IL-17A, IL-17F, IL-17RA and IL- 17RC, but not IL-17RB was significantly elevated in NSCLC compared with controls, while IL-17E was reduced. The median numbers of infiltrating lymphocytes and neutrophils and global macrophage (CD68) immunoreactivity of phagocytes were also elevated in NSCLC compared with control tissue sections. Furthermore, correlation between the expression of IL-17A and its receptors IL-17RA and IL- 17RC varied according to NSCLC histopathological type. These data suggest that IL-17A, E, F and their receptors IL-17RA, RB, RC may be involved in the pathogenesis of NSCLC. Further understanding of the relationship between the IL-17/IL-17R axis and the tumour inflammatory microenvironment may reveal new therapeutic targets.

Hsa_circ_0005986 inhibits carcinogenesis by acting as a miR-129-5p sponge and is used as a novel biomarker for hepatocellular carcinoma

Circular RNAs (circRNAs), a class of long-time-ignored noncoding RNA, have been revealed as multifunctional RNAs in recent years. However, the diagnostic values and the mechanism of most circRNAs in hepatocellular carcinoma (HCC) remain unknown. In this study, we revealed that the expression level of hsa_circ_0005986 in HCC was significantly lower than that in adjacent non-tumorous tissues (P < 0.001). Its levels in HCC cell lines, HepG2, SMMC7721, Huh7, MHCC97L, MHCC97H, and HCCLM3 were significantly lower than those in human normal hepatic cell line L02 (P < 0.001). In addition, the low expression level of hsa_circ_0005986 was correlated with chronic hepatitis B family history (P = 0.001), tumor diameters (P < 0.001), microvascular invasion (P = 0.026), and Barcelona Clinic Liver Cancer (BCLC) stage (P < 0.001). Further experiments demonstrated that both hsa_circ_0005986 and Notch1mRNA were targets of miR-129-5p, and that hsa_circ_0005986 downregulation liberated miR-129-5p and decreased the expression level of Notch1mRNA. More importantly, hsa_circ_0005986 downregulation accelerated cell proliferation by promoting the G0/G1 to S phase transition. We conclude that hsa_circ_0005986 function as microRNA sponge in tumorigenesis and can be used as a novel biomarker for HCC.

Regulatory Phosphorylation of Bacterial-Type PEP Carboxylase by the Ca2+-Dependent Protein Kinase RcCDPK1 in Developing Castor Oil Seeds

Phosphoenolpyruvate carboxylase (PEPC) is a tightly controlled cytosolic enzyme situated at a crucial branch point of central plant metabolism. In developing castor oil seeds (Ricinus communis) a novel, allosterically desensitized 910-kD Class-2 PEPC hetero-octameric complex, arises from a tight interaction between 107-kD plant-type PEPC and 118-kD bacterial-type (BTPC) subunits. The native Ca²⁺-dependent protein kinase (CDPK) responsible for in vivo inhibitory phosphorylation of Class-2 PEPC's BTPC subunit's at Ser-451 was highly purified from COS and identified as RcCDPK1 (XP_002526815) by mass spectrometry. Heterologously expressed RcCDPK1 catalyzed Ca²⁺-dependent, inhibitory phosphorylation of BTPC at Ser-451 while exhibiting: (i) a pair of Ca²⁺ binding sites with identical dissociation constants of 5.03 μM, (ii) a Ca²⁺-dependent electrophoretic mobility shift, and (iii) a marked Ca²⁺-independent hydrophobicity. Pull-down experiments established the Ca²⁺-dependent interaction of N-terminal GST-tagged RcCDPK1 with BTPC. RcCDPK1-Cherry localized to the cytosol and nucleus of tobacco bright yellow-2 cells, but colocalized with mitochondrial-surface associated BTPC-enhanced yellow fluorescent protein when both fusion proteins were coexpressed. Deletion analyses demonstrated that although its N-terminal variable domain plays an essential role in optimizing Ca²⁺-dependent RcCDPK1 autophosphorylation and BTPC transphosphorylation activity, it is not critical for in vitro or in vivo target recognition. Arabidopsis (Arabidopsis thaliana) CPK4 and soybean (Glycine max) CDPKβ are RcCDPK1 orthologs that effectively phosphorylated castor BTPC at Ser-451. Overall, the results highlight a potential link between cytosolic Ca²⁺ signaling and the posttranslational control of respiratory CO₂ refixation and anaplerotic photosynthate partitioning in support of storage oil and protein biosynthesis in developing COS.

Decreased expression of hsa_circ_0003570 in hepatocellular carcinoma and its clinical significance

BACKGROUND

Circular RNAs (circRNAs) constitute a class of non-coding RNAs recently discovered to be widespread and abundant in mammalian cells. However, the expression features of most of circRNAs in hepatocellular carcinoma (HCC) are unraveled. In this study, we focused on hsa_circ_0003570, which was found to be down-regulated in HCC tissues in our previous microarray screening.

METHODS

The hsa_circ_0003570 levels in HCC cell lines, HepG2, SMMC-7721, MHCC97L, MHCC97H, and HCCLM3, and human normal hepatic cell line L02 were detected by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Then, its levels in 107 paired HCC tissues and adjacent non-tumor tissues, 60 liver biopsy samples from patients with chronic liver diseases were detected by qRT-PCR. The receiver operating characteristic curve (ROC) was used to evaluate the diagnostic value of hsa_circ_0003570 for HCC.

RESULTS

Hsa_circ_0003570 was not only first found down-regulated in HCC cell lines (P<.001) but also in HCC tissues (P<.001). Moreover, hsa_circ_0003570 was gradually decreased from chronic hepatitis (CH), to liver cirrhosis (LC) and to HCC tissues (P<.01). Its expression levels were significantly correlated with tumor diameter (P=.035), differentiation (P=.013), microvascular invasion (P=.045), Barcelona Clinic Liver Cancer stages (P=.011), tumor-node-metastasis stages (P=.016), and serum alpha-fetoprotein levels (P=.031). The ROC curve demonstrated that hsa_circ_0003570 had poor performance for differentiating HCC from LC and CH, but had relatively good performance for differentiating LC from CH.

CONCLUSIONS

These results indicated that hsa_circ_0003570 expression levels were associated with HCC clinicopathological characteristics.

Strain softening of nano-scale fuzzy interfaces causes Mullins effect in thermoplastic polyurethane

The strain-induced softening of thermoplastic polyurethane elastomers (TPUs), known as the Mullins effect, arises from their multi-phase structure. We used the combination of small- and wide- angle X-ray scattering (SAXS/WAXS) during in situ repeated tensile loading to elucidate the relationship between molecular architecture, nano-strain, and macro-scale mechanical properties. Insights obtained from our analysis highlight the importance of the ‘fuzzy interface’ between the hard and soft regions that governs the structure evolution at nanometre length scales and leads to macroscopic stiffness reduction. We propose a hierarchical Eshelby inclusion model of phase interaction mediated by the ‘fuzzy interface’ that accommodates the nano-strain gradient between hard and soft regions and undergoes tension-induced softening, causing the Mullins effect that becomes apparent in TPUs even at moderate tensile strains.

Cigarette smoking increases bronchial mucosal IL-17A expression in asthmatics, which acts in concert with environmental aeroallergens to engender neutrophilic inflammation

BACKGROUND

Mild asthmatics who smoke cigarettes may develop unstable disease and neutrophilic infiltration of the airways, features more usually associated with severe asthmatic disease. The mechanisms giving rise to this response remain unclear.

OBJECTIVE

To address the hypothesis that smoking increases bronchial mucosal production of IL-17A which acts on bronchial epithelial cells directly and in concert with other environmental stimuli to induce the production of IL-6 and neutrophil chemotaxins.

METHODS

IL-17A, IL-8, IL-6, neutrophils and eosinophils were detected and quantified by immunohistochemistry in endobronchial biopsy sections from smoking and non-smoking asthmatics. Human tracheal epithelial cells (HTEpC) were cultured with IL-17A in the presence/absence of cigarette smoke extract (CSE) and aeroallergens lacking intrinsic protease activity, and IL-6 and IL-8 production measured in vitro.

RESULTS

Expression of IL-17A, IL-6 and IL-8 and neutrophil numbers was significantly elevated in the bronchial mucosa of the asthmatic smokers compared to the non-smokers. Expression of IL-17A correlated with that of IL-8 and neutrophil numbers. In the smoking asthmatics, eosinophil numbers also correlated with expression of IL-8 and IL-17A. Exposure of HTEpC cells to both CSE and IL-17A increased expression of IL-6 and IL-8 in a concentration-dependent and synergistic manner. Co-stimulation with CSE, IL-17A and aeroallergens further increased IL-6 and IL-8 production synergistically.

CONCLUSIONS

The data support the hypothesis that asthmatic smokers develop neutrophilic inflammation of the airways propagated at least partly by smoke-induced production of IL-17A which together with smoke and other environmental stimuli acts on airways epithelial cells to induce neutrophil chemotaxins.

Analysis of genes that influence sheep follicular development by different nutrition levels during the luteal phase using expression profiling

Nutrition is an important factor that regulates reproductive performance of sheep and affects follicle development. However, the correlation between nutrition and follicle development is poorly understood at the molecular level. To study its possible molecular mechanisms, we performed expression profiling of granulosa cells isolated from sheep that were fed different levels of nutrition levels during the luteal phase. To do this, ewes received a maintenance diet (M), and their estrus was synchronized by intravaginal progestogen sponges for 12 days. Ewes were randomly divided into the short-term dietary-restricted group (R; 0.5 × M) and the nutrient-supplemented group (S; 1.5 × M). RNA samples were extracted from granulosa cells. Transcriptome libraries from each group were constructed by Illumina sequencing. Among 18 468 detected genes, 170 genes were significantly differentially expressed, of which 140 genes were upregulated and 30 genes were downregulated in group S relative to group R. These genes could be candidates regulating follicular development in sheep. Gene Ontology, KEGG and clustering analyses were performed. Genes related to oocyte meiosis, such as ADCY7, were upregulated. We identified two important groups of related genes that were upregulated with improved nutrition: one group comprising the genes PTGS2, UCP2 and steroidogenic acute regulatory protein and the other group comprising interleukin-1A and interleukin-1B. The genes within each group showed similar expression patterns. Additionally, all five genes are involved in the reproduction process. Quantitative real-time PCR was performed to validate the results of expression profiling. These data in our study are an abundant genomic resource to expand the understanding of the molecular and cellular events underlying follicle development.

Resistin-like molecule-β (RELM-β) targets airways fibroblasts to effect remodelling in asthma: from mouse to man

BACKGROUND

RELM-β has been implicated in airways inflammation and remodelling in murine models. Its possible functions in human airways are largely unknown. The aim was to address the hypothesis that RELM-β plays a role in extracellular matrix deposition in asthmatic airways.

METHODS

The effects of RELM-β gene deficiency were studied in a model of allergen exposure in mice sensitised and challenged with Aspergillus fumigatus (Af). RELM-β expression was investigated in bronchial biopsies from asthmatic patients. Direct regulatory effects of RELM-β on human lung fibroblasts were examined using primary cultures and the MRC5 cell line in vitro.

RESULTS

Sensitisation and challenge of wild-type mice with Af-induced release of RELM-β with a time course coincident with that of procollagen in the airways. Af-induced expression of mRNA encoding some, but not all ECM in the lung parenchyma was attenuated in RELM-β-/- mice. RELM-β expression was significantly increased in the bronchial submucosa of human asthmatics compared with controls, and its expression correlated positively with that of fibronectin and α-smooth muscle actin. In addition to epithelial cells, macrophages, fibroblasts and vascular endothelial cells formed the majority of cells expressing RELM-β in the submucosa. Exposure to RELM-β increased TGF-β1, TGF-β2, collagen I, fibronectin, smooth muscle α-actin, laminin α1, and hyaluronan and proteoglycan link protein 1 (Hapl1) production as well as proliferation by human lung fibroblasts in vitro. These changes were associated with activation of ERK1/2 in MRC5 cells.

CONCLUSION

The data are consistent with the hypothesis that elevated RELM-β expression in asthmatic airways contributes to airways remodelling at least partly by increasing fibroblast proliferation and differentiation with resulting deposition of extracellular matrix proteins.

Elevations in T-helper-2-initiating cytokines (interleukin-33, interleukin-25 and thymic stromal lymphopoietin) in lesional skin from chronic spontaneous ('idiopathic') urticaria

BACKGROUND

The mechanism of wealing in chronic spontaneous urticaria (CSU) is largely unknown. We previously demonstrated increased expression of T-helper 2 [interleukin (IL)-4 and IL-5] cytokines in skin biopsies from CSU. This suggested that Th2-initiating cytokines [IL-33, IL-25 and thymic stromal lymphopoietin (TSLP)], released through innate immune mechanisms, may play a role in pathogenesis.

OBJECTIVES

To identify Th2-initiating cytokines in lesional and nonlesional skin from patients with CSU and to compare the results with a control group.

METHODS

Paired biopsies (one from a 4-8 h spontaneous weal and one from uninvolved skin) were taken from eight patients with CSU and nine control subjects, and studied by immunohistochemistry and confocal microscopy.

RESULTS

There were increases in IL-4(+) and IL-5(+) cells in lesional skin vs. controls (P = 0·03 and P < 0·001, respectively) and marked elevations in the numbers of IL-33(+), IL-25(+) and TSLP(+) cells in the dermis of lesional skin vs. both nonlesional skin (P = 0·002, P = 0·01 and P = 0·04, respectively) and controls (P = 0·001, P < 0·001 and P = 0·005, respectively). There was also a correlation between the numbers of IL-33(+) and IL-25(+) cells (r = 0·808, P = 0·015). IL-33 localized to CD31(+) endothelial cells, CD90(+) fibroblasts, CD68(+) macrophages and tryptase(+) mast cells, whereas IL-25 was expressed by epithelial cells, mast cells and major basic protein-positive eosinophils. IL-33 and IL-25 were constitutively expressed in the epidermis of both controls and patients with CSU.

CONCLUSIONS

Increased expression of Th2-initiating cytokines in lesional skin in CSU suggests that innate pathways might play a role in the mechanism of wealing. As Th2-initiating cytokines play a role in mast cell activation, inflammation and vascular leakage in CSU, these findings may also have therapeutic implications.

X-ray Study of Human Dental Tissues Affected by Erythroblastosis Fetalis

Numerous diseases are known to cause microstructural alteration of dental tissues structure. One type in particular is associated with neonatal jaundice and circulation of bilirubin in blood at high concentration due to increased hemolysis in conditions such as erythroblastosis fetalis, septicemia, biliary atresia, and other causes of hyperbilirubinemia. In those conditions, the products of the catabolism of hemoglobin end up deposited in various tissues, including teeth, where they can present clinically as visibly stained brown/green teeth. There is almost no information on the nature or extent of the structural changes taking place in these conditions. Here, advanced nondestructive wide-angle synchrotron X-ray scattering techniques combined with scanning microscopy methods were used to investigate for the first time the ultrastructure of the dental hard tissues in an archival case of intrinsically pigmented green teeth. Despite no obvious elemental variation across the pigmented tissue region, the high-resolution crystallographic properties probed by wide-angle synchrotron X-ray scattering revealed an ultrastructural variation (orientation, particle size, and lattice parameter of hydroxyapatite crystallites) associated with a pigmentation line in dentine and with a distinct neonatal line in enamel.

Calcitonin gene-related peptide and vascular endothelial growth factor are expressed in lesional but not uninvolved skin in chronic spontaneous urticaria

BACKGROUND

The mechanisms for producing weals in chronic spontaneous (idiopathic) urticaria (CSU) are incompletely understood. Leucocyte infiltration with vascular leakage and expression of the potent vasoactive agents' calcitonin gene-related peptide (CGRP) and vascular endothelial growth factor (VEGF) are features of late-phase allergic skin reactions, previously proposed as a model of CSU.

OBJECTIVE

To measure CGRP and VEGF expression in lesional and non-lesional skin from CSU patients and to compare results with a control group.

METHODS

Eight paired biopsies (one from 4-8 h spontaneous weals and one from uninvolved skin) were taken from eight patients with CSU and nine control subjects and studied by immunohistochemistry and confocal microscopy.

RESULTS

Lesional skin in CSU contained significantly more CGRP+ and VEGF+ cells than non-lesional skin. No significant differences were observed in CGRP and VEGF expression between non-lesional skin and controls. In lesional skin, VEGF and CGRP co-localised to UEA-1+ blood vessels. CGRP was also expressed by neutrophils and eosinophils and to a lesser extent by CD90(+) fibroblasts, mast cells, CD3(+) and CD68(+) cells. CGRP and VEGF expression was not related to the duration of disease.

CONCLUSION AND CLINICAL RELEVANCE

Increased expression of CGRP and VEGF in lesional, but not uninvolved, skin indicates that these potent vasoactive agents may play a role in wealing and tissue oedema in CSU so representing novel targets in therapy.

Direct comparison of the dynamics of IL-25- and 'allergen'-induced airways inflammation, remodelling and hypersensitivity in a murine asthma model

BACKGROUND

Interleukin-25 has been implicated in the pathogenesis of asthma from studies on human asthmatics and in murine asthma models.

OBJECTIVES

In this study, we hypothesized that chronic exposure of the airways to IL-25 alone is able to induce pathogenic changes observed in animal models of asthma.

METHODS

We performed a detailed comparison of the dynamics of development of cellular infiltration, cytokine expression and airways remodelling and hyperresponsiveness in mice sensitized and challenged with OVA, a classical model of allergic asthma and those exposed to IL-25 alone.

RESULTS

Intranasal challenge of BALB/c mice with IL-25 alone induced a delayed (compared with OVA-challenge), predominantly eosinophilic and lymphocytic infiltration into the airways lumen, along with increased production of Th2-type cytokines, chemokines and collagen, secretion of epithelial mucus, goblet cell hyperplasia, deposition of subepithelial collagen, airways smooth muscle cell hyperplasia and angiogenesis. Correspondingly, IL-25 as well as OVA challenge both induced airways hyperresponsiveness and increased lung tissue damping. In contrast, IL-25 exposure did not increase IgE or IgG1 production.

CONCLUSIONS AND CLINICAL RELEVANCE

The data suggest that chronic airways exposure to IL-25 alone is sufficient to induce allergen- and IgE-independent, asthma-like airways inflammation, remodelling and hyperresponsiveness in mice. Thus, IL-25 is a key molecular target in asthma, irrespective of the coexistence of IgE-dependent mechanisms.

Biochemical and molecular characterization of RcSUS1, a cytosolic sucrose synthase phosphorylated in vivo at serine 11 in developing castor oil seeds

Sucrose synthase (SUS) catalyzes the UDP-dependent cleavage of sucrose into UDP-glucose and fructose and has become an important target for improving seed crops via metabolic engineering. A UDP-specific SUS homotetramer composed of 93-kDa subunits was purified to homogeneity from the triacylglyceride-rich endosperm of developing castor oil seeds (COS) and identified as RcSUS1 by mass spectrometry. RcSUS1 transcripts peaked during early development, whereas levels of SUS activity and immunoreactive 93-kDa SUS polypeptides maximized during mid-development, becoming undetectable in fully mature COS. The cytosolic location of the enzyme was established following transient expression of RcSUS1-enhanced YFP in tobacco suspension cells and fluorescence microscopy. Immunological studies using anti-phosphosite-specific antibodies revealed dynamic and high stoichiometric in vivo phosphorylation of RcSUS1 at its conserved Ser-11 residue during COS development. Incorporation of (32)P(i) from [γ-(32)P]ATP into a RcSUS1 peptide substrate, alongside a phosphosite-specific ELISA assay, established the presence of calcium-dependent RcSUS1 (Ser-11) kinase activity. Approximately 10% of RcSUS1 was associated with COS microsomal membranes and was hypophosphorylated relative to the remainder of RcSUS1 that partitioned into the soluble, cytosolic fraction. Elimination of sucrose supply caused by excision of intact pods of developing COS abolished RcSUS1 transcription while triggering the progressive dephosphorylation of RcSUS1 in planta. This did not influence the proportion of RcSUS1 associated with microsomal membranes but instead correlated with a subsequent marked decline in SUS activity and immunoreactive RcSUS1 polypeptides. Phosphorylation at Ser-11 appears to protect RcSUS1 from proteolysis, rather than influence its kinetic properties or partitioning between the soluble cytosol and microsomal membranes.

The cell wall-targeted purple acid phosphatase AtPAP25 is critical for acclimation of Arabidopsis thaliana to nutritional phosphorus deprivation

Plant purple acid phosphatases (PAPs) belong to a relatively large gene family whose individual functions are poorly understood. Three PAP isozymes that are up-regulated in the cell walls of phosphate (Pi)-starved (-Pi) Arabidopsis thaliana suspension cells were purified and identified by MS as AtPAP12 (At2g27190), AtPAP25 (At4g36350) and AtPAP26 (At5g34850). AtPAP12 and AtPAP26 were previously isolated from the culture medium of -Pi cell cultures, and shown to be secreted by roots of Arabidopsis seedlings to facilitate Pi scavenging from soil-localized organophosphates. AtPAP25 exists as a 55 kDa monomer containing complex NX(S/T) glycosylation motifs at Asn172, Asn367 and Asn424. Transcript profiling and immunoblotting with anti-AtPAP25 immune serum indicated that AtPAP25 is exclusively synthesized under -Pi conditions. Coupled with potent mixed-type inhibition of AtPAP25 by Pi (I50 = 50 μm), this indicates a tight feedback control by Pi that prevents AtPAP25 from being synthesized or functioning as a phosphatase except when Pi levels are quite low. Promoter-GUS reporter assays revealed AtPAP25 expression in shoot vascular tissue of -Pi plants. Development of an atpap25 T-DNA insertion mutant was arrested during cultivation on soil lacking soluble Pi, but rescued upon Pi fertilization or complementation with AtPAP25. Transcript profiling by quantitative RT-PCR indicated that Pi starvation signaling was attenuated in the atpap25 mutant. AtPAP25 exhibited near-optimal phosphatase activity with several phosphoproteins and phosphoamino acids as substrates. We hypothesize that AtPAP25 plays a key signaling role during Pi deprivation by functioning as a phosphoprotein phosphatase rather than as a non-specific scavenger of Pi from extracellular P-monoesters.

Elevations in vascular markers and eosinophils in chronic spontaneous urticarial weals with low-level persistence in uninvolved skin

BACKGROUND

In chronic spontaneous urticaria (CSU) mast cell activation together with inflammatory changes in the skin are well documented and may play an important role in mechanisms of tissue oedema.

OBJECTIVES

To confirm and extend these observations by measuring microvascular markers, leucocytes and mast cell numbers in lesional and uninvolved skin and to compare findings with a control group.

METHODS

Paired biopsies (one from 4-8-h spontaneous weals and one from uninvolved skin) were taken from eight patients with CSU and nine control subjects and studied using immunohistochemistry and confocal microscopy using the lectin Ulex europaeus agglutinin 1 (UEA-1).

RESULTS

Lesional skin in CSU contained significantly more CD31+ endothelial cells; CD31+ blood vessels, neutrophils, eosinophils, basophils and macrophages; and CD3+ T cells than nonlesional skin. Increased vascularity was confirmed by confocal imaging using the lectin UEA-1. Uninvolved skin from CSU contained significantly more CD31+ endothelial cells, CD31+ blood vessels and eosinophils compared with the control subjects. There was a threefold increase in mast cell numbers when CSU was compared with controls but no difference was observed between lesional and uninvolved skin.

CONCLUSIONS

Increased vascular markers together with eosinophil and neutrophil infiltration are features of lesional skin in CSU and might contribute to tissue oedema. Eosinophils and microvascular changes persist in uninvolved skin, which, together with increased mast cells, suggests that nonlesional skin is primed for further wealing.

The impact of abdominal computed tomography in a tertiary referral centre emergency department on the management of patients with inflammatory bowel disease

BACKGROUND

Although exposure to diagnostic radiation may be associated with increased risk of malignancy, the use of abdominal CT (ACT) in the last decade has increased for patients in the emergency department (ED).

AIM

To examine the impact of ACT ordered in the ED on management of patients with inflammatory bowel diseases (IBD), as well as to quantify the cumulative effective dose (CED) of radiation received by these patients.

METHODS

A total of 152 patients with Crohn's disease (CD) and 130 patients with ulcerative colitis (UC) that presented to the ED in a tertiary centre between 2009 and 2011 were identified. For patients that had an ACT, chart review assessed if the ACT findings changed clinical management. CED of diagnostic radiation (DR) was calculated for all imaging studies between 1 January 2006 and 30 August 2012.

RESULTS

Abdominal CT use was 49% for CD and 19% for UC. ACTs with findings of penetrating/obstructive disease were 35% for CD. Urgent non-IBD-related diagnoses were found in 13% for CD and 28% for UC (P < 0.05). ACT caused a change in management in 81% of CD and 69% of UC patients. Mean CED from DR was 77.4 ± 63.0 mSv (median 53 mSv) for CD and 67.2 ± 51.0 mSv (median 56 mSv) for UC (P = 0.47). The CED for the 80-month period exceeded 75 mSv in 35% and 36% respectively (P = 0.99).

CONCLUSIONS

Although abdominal CT often changes management of IBD patients in the emergency department, this population carries a very high-risk of radiation exposure. Efforts should be made to decrease this risk by development of low-radiation protocols, and wider use of MRI/ultrasound.

Eliminating the purple acid phosphatase AtPAP26 in Arabidopsis thaliana delays leaf senescence and impairs phosphorus remobilization

Limitation of crop productivity by suboptimal phosphorus (P) nutrition is a widespread concern. Enhanced crop P-use efficiency could be achieved by improving P remobilization from senescing leaves to developing tissues and seeds. Transcriptomic studies indicate that hundreds of Arabidopsis thaliana genes are up-regulated during leaf senescence, including that encoding the purple acid phosphatase (PAP) AtPAP26 (At5g34850). In this study, biochemical and functional genomic tools were integrated to test the hypothesis that AtPAP26 participates in P remobilization during leaf senescence. An eightfold increase in acid phosphatase activity of senescing leaves was correlated with the accumulation of AtPAP26 transcripts and immunoreactive AtPAP26 polypeptides. Senescing leaves of an atpap26 T-DNA insertion mutant displayed a > 90% decrease in acid phosphatase activity, markedly impaired P remobilization efficiency and delayed senescence. This was paralleled by reduced seed total P concentrations and germination rates. These results demonstrate that AtPAP26 loss of function causes dramatic effects that cannot be compensated for by any other PAP isozyme, even though Arabidopsis contains 29 different PAP genes. Our current and earlier studies establish that AtPAP26 not only helps to scavenge P from organic P sources when Arabidopsis is cultivated in inorganic orthophosphate (Pi)-deficient soils, but also has an important P remobilization function during leaf senescence.

Interleukin-25 promotes basic fibroblast growth factor expression by human endothelial cells through interaction with IL-17RB, but not IL-17RA

BACKGROUND

Unlike other IL-17 family members, the Th2-derived cytokine IL-25 (IL-17E) induces (promotes) Th2 responses. One or both of the two receptors for IL-25 (IL-17RA, IL-17RB) is expressed on inflammatory cells and tissue structural cells, suggesting that in addition to promoting Th2-type inflammation IL-25 may also act on structural cells at sites of Th2-type inflammation such as in the asthmatic bronchial mucosa to promote remodelling changes.

OBJECTIVE

Our previous studies showed elevated expression of IL-25 and IL-17RB immunoreactivity in asthmatic airways with co-localization of the latter to endothelial cells. We therefore hypothesized that IL-25 acts on endothelial cells through this receptor to induce production of the key angiogenic and remodelling cytokine basic fibroblast growth factor (bFGF).

METHODS

Polymerase chain reaction (PCR) immunocytochemistry/immunohistochemistry and ELISA were employed to detect expression of IL-17RB, IL-17RA and bFGF by human vascular endothelial cells (HUVEC) and immunoreactivity for IL-25 and bFGF in asthmatic bronchial biopsies. Receptor-blocking antibodies, PCR and an in vitro angiogenesis assay were used to investigate whether IL-25 acts on IL-17RB or IL-17RA to induce bFGF expression and angiogenesis. PCR was also employed to investigate the signalling pathways involved in IL-25-mediated bFGF expression.

RESULTS

HUVEC constitutively expressed IL-17RB, IL-17RA and bFGF. Production of the latter was further increased by IL-25, but attenuated after blockade of the IL-17RB, but not the IL-17RA receptor. Neutralization of endogenous VEGF and bFGF completely abrogated IL-25-induced angiogenesis which was also inhibited by blocking IL-17RB, but not IL-17RA. The PI3K-specific inhibitor LY294002 also completely attenuated IL-25-induced bFGF expression. Immunoreactivity for IL-25 and bFGF was elevated in the asthmatic bronchial mucosa and the expression of each correlated with the other.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data support the hypothesis that IL-25 contributes to elevated bFGF in asthmatic airways by acting on the endothelial cell IL-17RB receptor through PI3K-signalling pathways. Targeting the pathways might benefit therapy of airways remodelling.

The secreted purple acid phosphatase isozymes AtPAP12 and AtPAP26 play a pivotal role in extracellular phosphate-scavenging by Arabidopsis thaliana

Orthophosphate (P(i)) is an essential but limiting macronutrient for plant growth. Extensive soil P reserves exist in the form of organic P (P(o)), which is unavailable for root uptake until hydrolysed by secretory acid phosphatases (APases). The predominant purple APase (PAP) isozymes secreted by roots of P(i)-deficient (-P(i)) Arabidopsis thaliana were recently identified as AtPAP12 (At2g27190) and AtPAP26 (At5g34850). The present study demonstrated that exogenous P(o) compounds such as glycerol-3-phosphate or herring sperm DNA: (i) effectively substituted for P(i) in supporting the P nutrition of Arabidopsis seedlings, and (ii) caused upregulation and secretion of AtPAP12 and AtPAP26 into the growth medium. When cultivated under -P(i) conditions or supplied with P(o) as its sole source of P nutrition, an atpap26/atpap12 T-DNA double insertion mutant exhibited impaired growth coupled with >60 and >30% decreases in root secretory APase activity and rosette total P(i) concentration, respectively. Development of the atpap12/atpap26 mutant was unaffected during growth on P(i)-replete medium but was completely arrested when 7-day-old P(i)-sufficient seedlings were transplanted into a -P(i), P(o)-containing soil mix. Both PAPs were also strongly upregulated on root surfaces and in shoot cell-wall extracts of -P(i) seedlings. It is hypothesized that secreted AtPAP12 and AtPAP26 facilitate the acclimation of Arabidopsis to nutritional Pi deficiency by: (i) functioning in the rhizosphere to scavenge P(i) from the soil's accessible P(o) pool, while (ii) recycling P(i) from endogenous phosphomonoesters that have been leaked into cell walls from the cytoplasm. Thus, AtPAP12 and AtPAP26 are promising targets for improving crop P-use efficiency.

Inhibin activin subunits and activin receptors in human breast cell-lines and lactating rat mammary-glands

We have reported previously that a human breast cancer cell line, MCF-7, transcribes messenger RNAs coding inhibin/activin alpha-, beta A-, and beta B-subunits and activin receptor II as well as produces inhibin and/or activin proteins, using immunocytochemistry, in situ hybridization, and the reverse transcription-polymerase chain reaction (RT-PCR) analysis. In the present study, we report that four additional cell lines derived from human breast cancers, T47D, HS-578, ZR-75-1, and MDA-MB 321 express mRNAs for alpha- and beta-subunits of inhibin/activin and activin receptors as well as stain positive with antisera specific for inhibin alpha- and inhibin/activin beta-subunits, respectively. We have also localized immunocytochemically inhibin and activin-A in rat lactating mammary glands and found mRNAs for activin receptors I, II, and IIB as well as follistatin, a binding protein for activin, in lactating rat mammary glands by RT-PCR. These findings provide additional evidence that inhibin and activin may be involved in regulating the normal and abnormal cell growth of mammary glands.

Overexpression of activin A inhibits growth, induces apoptosis, and suppresses tumorigenicity in an androgen-sensitive human prostate cancer cell line LNCaP

The effects of overexpression of activin A in the androgen-sensitive human prostate cancer cell line LNCaP were studied. A full-length cDNA of activin beta A coding region was inserted into a eukaryotic expression vector and transfected into the LNCaP cells. Overexpression of activin BA significantly inhibited growth of this cell line. An increased death rate was also noted in these activin-overproducing cells, which was believed to be due to apoptosis as manifested by morphological change, DNA laddering, and FAGS analysis. The expression of bcl-2 was suppressed and the expression of c-myc was stimulated in these cells. In addition, the efficiency of soft agar colony formation and the tumorigenicity in the nude mice were suppressed for the activin producing LNCaP cells.

A maize stress-responsive NAC transcription factor, ZmSNAC1, confers enhanced tolerance to dehydration in transgenic Arabidopsis

NAC proteins are plant-specific transcription factors that play essential roles in stress responses. However, only little information regarding stress-related NAC genes is available in maize. In this study, a maize NAC gene, ZmSNAC1, was cloned and functionally characterized. Expression analysis revealed that ZmSNAC1 was strongly induced by low temperature, high-salinity, drought stress, and abscisic acid (ABA) treatment, but downregulated by salicylic acid treatment. Subcellular localization experiments in Arabidopsis protoplast cells indicated that ZmSNAC1 was localized in the nucleus. Transactivation assays demonstrated that ZmSNAC1 functioned as a transcriptional activator. Overexpression of ZmSNAC1 in Arabidopsis led to hypersensitivity to ABA and osmotic stress at the germination stage, but enhanced tolerance to dehydration compared to wild-type seedlings. These results suggest that ZmSNAC1 functions as a stress-responsive transcription factor in positive modulation of abiotic stress tolerance, and may have applications in the engineering of drought-tolerant crops.

KEY MESSAGE

ZmSNAC1 functioned as a stress-responsive transcription factor in response to abiotic stresses, and might be useful for crop tolerance improvement.

Follicular development and expression of nuclear respiratory factor-1 and peroxisome proliferator-activated receptor γ coactivator-1 alpha in ovaries of fetal and neonatal doelings

In livestock, the ovarian reserve of follicles is established during the fetal stage. However, at least two-thirds of the oocytes present in the reserve die because of apoptosis before birth. Notably, mitochondria have been reported to play a crucial role in the fate (life/death) of oocytes. In this study, mitochondrial regulators nuclear respiratory factor-1 (NRF-1) and PPAR γ coactivator-1 alpha (PGC-1α) were examined during this period of follicle development to investigate their effects on follicular development and apoptosis. Fetal and neonatal Capra haimen were used, ranging in age from 60 d postcoitum (dpc) to 30 d postpartum (dpp). Our data demonstrated that egg nests were the earliest recognizable gamete cells in ovaries of fetal and neonatal doelings. Proportions of egg nests decreased from 92.68 to 25.08% whereas single follicles increased from 7.32 to 74.92% between 60 and 120 dpc. Subsequently, between 90 and 120 dpc, the proportion of primordial follicles increased from 9.98 to 61.56% (P < 0.01). However, it did not change between 1 and 30 dpp (P = 0.12). The proportion of primary follicles increased from 1.23 to 37.93% between 90 dpc to 1 dpp (P = 0.01) but did not change between 1 and 30 dpp (P = 0.11). Meanwhile, proportions of secondary and tertiary follicles increased in an age-dependent manner. In addition, results of this study suggested that NRF-1 and PGC-1α proteins are mainly localized in germ cells of egg nests, cytoplasm of oocytes, and granulosa cells of follicles ranging from primordial to tertiary follicles. The transcript abundance of NRF-1 mRNA was up-regulated in 60-dpc-old ovaries compared with 1-dpp-old ovaries (P < 0.05), but the PGC-1α mRNA expression pattern did not change (P = 0.05). Nevertheless, the number of terminal deoxynucleotidyltransferase UTP nick-end labeling (TUNEL) positive cells and caspase-3 activity in 60-dpc-old ovaries was less than those in 1-dpp-old ovaries (P < 0.01, P = 0.01). In conclusion, our results demonstrate that the key stage of primordial follicle formation is between 90 and 120 dpc in Capra haimen. Also, this study suggests that NRF-1 and PGC-1α might have roles in cell apoptosis during ovarian development of fetal and neonatal Capra haimen. These results improve our understanding of apoptotic mechanisms in oogenesis and folliculogenesis.

Isolation and characterization of maize PMP3 genes involved in salt stress tolerance

Plasma membrane protein 3 (PMP3), a class of small hydrophobic polypeptides with high sequence similarity, is responsible for salt, drought, cold, and abscisic acid. These small hydrophobic ploypeptides play important roles in maintenance of ion homeostasis. In this study, eight ZmPMP3 genes were cloned from maize and responsive to salt, drought, cold and abscisic acid. The eight ZmPMP3s were membrane proteins and their sequences in trans-membrane regions were highly conserved. Phylogenetic analysis showed that they were categorized into three groups. All members of group II were responsive to ABA. Functional complementation showed that with the exception of ZmPMP3-6, all were capable of maintaining membrane potential, which in turn allows for regulation of intracellular ion homeostasis. This process was independent of the presence of Ca(2+). Lastly, over-expression of ZmPMP3-1 enhanced growth of transgenic Arabidopsis under salt condition. Through expression analysis of deduced downstream genes in transgenic plants, expression levels of three ion transporter genes and four important antioxidant genes in ROS scavenging system were increased significantly in transgenic plants during salt stress. This tolerance was likely achieved through diminishing oxidative stress due to the possibility of ZmPMP3-1's involvement in regulation of ion homeostasis, and suggests that the modulation of these conserved small hydrophobic polypeptides could be an effective way to improve salt tolerance in plants.

Cloning and characterization of a maize bZIP transcription factor, ZmbZIP72, confers drought and salt tolerance in transgenic Arabidopsis

In plants, the bZIP (basic leucine zipper) transcription factors regulate diverse functions, including processes such as plant development and stress response. However, few have been functionally characterized in maize (Zea mays). In this study, we cloned ZmbZIP72, a bZIP transcription factor gene from maize, which had only one copy in the maize genome and harbored three introns. Analysis of the amino acid sequence of ZmbZIP72 revealed a highly conserved bZIP DNA-binding domain in its C-terminal region, and four conserved sequences distributed in N- or C-terminal region. The ZmbZIP72 gene expressed differentially in various organs of maize plants and was induced by abscisic acid, high salinity, and drought treatment in seedlings. Subcellular localization analysis in onion epidermal cells indicated that ZmbZIP72 was a nuclear protein. Transactivation assay in yeast demonstrated that ZmbZIP72 functioned as a transcriptional activator and its N terminus (amino acids 23-63) was necessary for the transactivation activity. Heterologous overexpression of ZmbZIP72 improved drought and partial salt tolerance of transgenic Arabidopsis plants, as determined by physiological analyses of leaf water loss, electrolyte leakage, proline content, and survival rate under stress. In addition, the seeds of ZmbZIP72-overexpressing transgenic plants were hypersensitive to ABA and osmotic stress. Moreover, overexpression of ZmbZIP72 enhanced the expression of ABA-inducible genes such as RD29B, RAB18, and HIS1-3. These results suggest that the ZmbZIP72 protein functions as an ABA-dependent transcription factor in positive modulation of abiotic stress tolerance and may be a candidate gene with potential application in molecular breeding to enhance stress tolerance in crops.

Cloning and characterization of a maize SnRK2 protein kinase gene confers enhanced salt tolerance in transgenic Arabidopsis

SnRK2 (sucrose non-fermenting 1-related protein kinases 2) represents a unique family of protein kinase in regulating signaling transduction in plants. Although the regulatory mechanisms of SnRK2 have been well demonstrated in Arabidopsis thaliana, their functions in maize are still unknown. In our study, we cloned an SnRK2 gene from maize, ZmSAPK8, which encoded a putative homolog of the rice SAPK8 protein. ZmSAPK8 had two copies in the maize genome and harbored eight introns in its coding region. We demonstrated that ZmSAPK8 expressed differentially in various organs of maize plants and was up-regulated by high-salinity and drought treatment. A green fluorescent protein (GFP)-tagged ZmSAPK8 showed subcellular localization in the cell membrane, cytoplasm and nucleus. In vitro kinase assays indicated that ZmSAPK8 preferred Mn(2+) to Mg(2+) as cofactor for phosphorylation, and Ser-182 and Thr-183 in activation loop was important for its activity. Heterologous overexpression of ZmSAPK8 in Arabidopsis could significantly strengthen tolerance to salt stress. Under salt treatment, ZmSAPK8-overexpressed transgenic plants exhibited higher germination rate and proline content, low electrolyte leakage and higher survival rate than wild type. Further analysis indicated that transgenic plants showed increased transcription of the stress-related genes, RD29A, RD29B, RAB18, ABI1, DREB2A and P5CS1, under high-salinity conditions. The results demonstrated that ZmSAPK8 was involved in diverse stress signal transduction. Moreover, no obvious adverse effects on growth and development in the ZmSAPK8-overexpressed transgenic plants implied that ZmSAPK8 was potentially useful in transgenic breeding to improve salt tolerance in crops.