Combined metabolome and transcriptome analysis reveals a critical role of lignin biosynthesis and lignification in stem-like pneumatophore development of the mangrove Avicennia marina

MAIN CONCLUSION

Transcriptional and metabolic regulation of lignin biosynthesis and lignification plays crucial roles in Avicennia marina pneumatophore development, facilitating its adaptation to coastal habitats. Avicennia marina is a pioneer mangrove species in coastal wetland. To cope with the periodic intertidal flooding and hypoxia environment, this species has developed a complex and extensive root system, with its most unique feature being a pneumatophore with a distinct above- and below-ground morphology and vascular structure. However, the characteristics of pneumatophore lignification remain unknown. Studies comparing the anatomy among above-ground pneumatophore, below-ground pneumatophore, and feeding root have suggested that vascular structure development in the pneumatophore is more like the development of a stem than of a root. Metabolome and transcriptome analysis illustrated that the accumulation of syringyl (S) and guaiacyl (G) units in the pneumatophore plays a critical role in lignification of the stem-like structure. Fourteen differentially accumulated metabolites (DAMs) and 10 differentially expressed genes involved in the lignin biosynthesis pathway were targeted. To identify genes significantly associated with lignification, we analyzed the correlation between 14 genes and 8 metabolites and further built a co-expression network between 10 transcription factors (TFs), including 5 for each of MYB and NAC, and 23 enzyme-coding genes involved in lignin biosynthesis. 4-Coumarate-CoA ligase, shikimate/quinate hydroxycinnamoyl transferase, cinnamyl alcohol dehydrogenase, caffeic acid 3-O-methyltransferase, phenylalanine ammonia-lyase, and peroxidase were identified to be strongly correlated with these TFs. Finally, we examined 9 key candidate genes through quantitative real-time PCR to validate the reliability of transcriptome data. Together, our metabolome and transcriptome findings reveal that lignin biosynthesis and lignification regulate pneumatophore development in the mangrove species A. marina and facilitate its adaptation to coastal habitats.

Robotic-assisted intracorporeal versus extracorporeal techniques in sigmoidectomy: a propensity score-matched analysis

Scarce research has been performed to assess the safety and efficacy of anastomosis technique on robotic-assisted sigmoidectomy. This study was designed to evaluate the difference between intracorporeal and extracorporeal techniques during robotic-assisted sigmoidectomy. Clinical data of 193 cases who received robotic-assisted sigmoidectomy were retrospectively collected and analyzed. Only 116 cases were available for analysis (intracorporeal group = 58 and extracorporeal group = 58) after propensity score matching. Independent sample t test was conducted to evaluate the continuous variables. Moreover, the statistical significance of categorical variables was tested using Chi-square or Fisher's exact tests. Statistical analysis showed that the intracorporeal group demonstrated greater superiorities in pain scale on the first and second postoperative day (P < 0.05), time of catheter indwelling (P = 0.009), and length of hospital stay (P = 0.019). Additionally, the intracorporeal technique contributed to fewer complications including urinary retention (P = 0.027) and hernia (P = 0.037) than the extracorporeal group. Our analysis revealed that intracorporeal technique was safe and feasible due to the shorter time of catheter indwelling and length of hospital stay and fewer post-operation complications.

[Clinical characteristics of 14 cases of neonatal tracheotomy in neonatal intensive care unit]

Objective: To analyze the clinical characteristics of neonatal tracheotomy in neonatal intensive care unit (NICU). Methods: This single-center retrospective study included 14 neonates admitted to NICU of Beijing Children's Hospital, Capital Medical University from January 2016 to August 2021, and were<28 days of age on admission, who met the criteria of tracheotomy and finally completed the procedure. The clinical characteristics including age, weight, duration of ventilation, etiology of tracheotomy, length of hospital stay and prognosis were summarized and analyzed. Wilcoxon signed-rank test was used to compare the weight gain velocity and the duration of ventilation before and after tracheotomy. Paired t-test was used to compare the hospitalization length before and after tracheotomy. Spearman correlation was used to analyze the correlation between the clinical characteristics and outcomes. Results: For the 14 neonates, the gestational age was (38±4) weeks and birth weight was (2 824±949) g. Nine of them were male. The age on transportation was 16 (6, 25) d. A total of 10 neonates were on invasive ventilation on admission, the other 4 were on nasal continuous positive airway pressure support. Bilateral vocal cord paralysis (7 cases) was the commonest cause of tracheotomy. The age on operation was 33 (22, 44) d. There were statistically significant differences in duration of ventilation and weight gain velocity before and after operation (19.00 (10.50, 34.00) vs. 0.86 (0.06, 3.25) d, 1.66 (-0.16, 5.54) vs. 4.69 (2.30, 9.32) g/(kg·d), Z=3.01 and -1.98, both P<0.05). The total hospital stay in NICU was (37±12) d. One neonate died during hospitalization. The existence of pneumonia on admission was positively correlated to NICU stay length (r=0.57, P=0.027), the pre-operational weight gain velocity was negatively correlated to the post-operational NICU stay length (r=-0.73, P=0.020). There were 4 neonates de-cannulated during 7-38 months after the tracheotomy, and 5 neonates still wearing the tracheal cannulation during 15-66 months after the tracheotomy. Two neonates died and 2 neonates lost follow-up after discharge. All neonates could not vocalize normally before de-cannulation, and the language development obviously lagged behind the normal age group after de-cannulation. Conclusions: Bilateral vocal cord paralysis is the commonest cause of neonatal tracheotomy. The benefit of tracheotomy for NICU neonates with surgical indications is obvious, especially in facilitating extubation and improving weight gain.

[Clinical characteristics and outcomes of 111 neonates with upper airway obstruction admitted via transportation]

Objectives: To analyze the clinical characteristics and outcomes of neonates with upper airway obstruction (UAO) who were admitted via transportation, hence to provide more evidence-based information for the clinical management of UAO. Methods: This was a single center retrospective study. Patients were hospitalized in Beijing Children's Hospital from January 1, 2016 to May 31, 2021 with age <28 days or postmenstrual age (PMA) ≤44 weeks, and UAO as the first diagnosis. The general information of patients, obstructed sites in the upper airway, treatment, complications and prognosis were analyzed. The outcomes of surgical UAO vs. non-surgical UAO were analyzed by 2 by 2 χ² test. Results: A total of 111 cases were analyzed (2.3% of the total NICU hospitalized 4 826 infants in the same period), in which 62 (55.9%) were boys and 101 (91.0%) were term infants, and their gestational age was (38.7±2.0) weeks, birth weight (3 207±585) g, PMA on admission (40.8±2.5) weeks and weight on admission was (3 221±478) g. There were 92 cases (82.9%) with symptoms of UAO presenting on postnatal day 1, and 35 cases (31.5%) had extra-uterine growth retardation on admission. The diagnosis of UAO and the obstructive site was confirmed in 25 cases (22.5%) before transportation. There were 24 cases (21.6%), 71 cases (64.0%), and 16 cases (14.4%) who had UAO due to nasal, throat, and neck problems, respectively. The top 5 diagnosis of UAO were vocal cord paralysis (28 cases), bilateral choanal atresia (20 cases), laryngomalacia (15 cases), pharynx and larynx cysts (7 cases), and subglottic hemangioma (6 cases). The diagnosis and treatment of all the patients followed a multidisciplinary approach consisted of neonatal intensive care unit, ear-nose-throat department and medical image departments. A total of 102 cases (91.9%) underwent both bronchofiberscope and fiber nasopharyngoscope investigation. Seventy cases (63.1%) required ventilation. Among the 58 cases (52.3%) who required surgical intervention, 16 had tracheotomy. For cases with vs. without surgical intervention, the rate of cure and (or) improvement were 94.8% (55/58) vs. 54.7% (29/53), and the rate of being discharged against medical arrangement were 1.7% (1/58) vs. 45.3% (24/53) (χ²=24.21 and 30.11, both P<0.01). Conclusions: Neonatal UAO may locate at various sites of the upper airway. The overall prognosis of neonatal UAO is favorable. A multidisciplinary approach is necessary for efficient evaluation and appropriate surgical intervention.

[Introduction of landmarking approach and its application in dynamic prediction]

Conventional prediction model, as a static prediction model, can be only used to predict the probability of the occurrence of an event during the observation period using the information available at baseline survey. However, based on current clinical demands, dynamic prediction, which obtains prediction probabilities for both baseline survey and later time points given the history of the events and covariates up to that time, is gaining a growing attention. As a dynamic prediction model, the landmarking approach is simple, easy to use, computationally efficient and has a comparable performance of joint modeling, which makes it to be widely used in recent researches. Because of its limited application in China, this paper makes a brief introduction of its ideas and basic application to further promote its applications in clinical dynamic prediction.

Source or sink? A study on the methane flux from mangroves stems in Zhangjiang estuary, southeast coast of China

Mangrove ecosystems are an important component of "blue carbon". However, it is not clear whether the stems play roles in the CH₄ budget of mangrove ecosystems. This study investigated the CH₄ emission from mangrove stems and its potential driving factors. We set up six sample plots in the Zhangjiang Estuary National Mangrove Nature Reserve, where Kandelia obovata, Avicennia marina and Aegiceras corniculata are the main mangrove tree species. Soil properties such as total carbon content, redox potential and salinity were determined in each plot. The dynamic chamber method was used to measure mangrove stems and soil CH₄ fluxes. Combined field survey results with Principal Component Analysis (PCA) of soil properties, we divided the six plots into two sites (S1 and S2) to perform statistical analyses of stem CH₄ fluxes. Then the CH₄ fluxes from mangrove tree stems and soil were further scaled up to the ecosystem level through the mapping model. Under different backgrounds of soil properties, salinity and microbial biomass carbon were the main factors modified soil CH₄ fluxes in the two sites, and further affected the stem CH₄ fluxes of mangroves. The soil of both sites are sources of CH₄, and the soil CH₄ emission of S2 was about twice higher than that of S1. Results of upscaling model showed that mangrove stems in S1 were CH₄ sinks with -105.65 g d^-1. But stems in S2 were CH₄ sources around 1448.24 g d^-1. Taken together, our results suggested that CH₄ emission from mangrove soils closely depends on soils properties. And mangrove stems were found to act as both CH₄ sources and CH₄ sinks depend on soil CH₄ production. Therefore, when calculating the CH₄ budget of the mangrove ecosystem, the contribution of mangrove plant stems cannot be ignored.

Physiological and Proteomic Analyses of Different Ecotypes of Reed (Phragmites communis) in Adaption to Natural Drought and Salinity

Drought and salinity are the two major abiotic stresses constraining the crop yield worldwide. Both of them trigger cellular dehydration and cause osmotic stress which leads to cytosolic and vacuolar volume reduction. However, whether plants share a similar tolerance mechanism in response to these two stresses under natural conditions has seldom been comparatively reported. There are three different ecotypes of reed within a 5 km2 region in the Badanjilin desert of Northwest China. Taking the typical swamp reed (SR) as a control, we performed a comparative study on the adaption mechanisms of the two terrestrial ecotypes: dune reed (DR) and heavy salt meadow reed (HSMR) by physiological and proteomic approaches coupled with bioinformatic analysis. The results showed that HSMR and DR have evolved C4-like photosynthetic and anatomical characteristics, such as the increased bundle sheath cells (BSCs) and chloroplasts in BSCs, higher density of veins, and lower density and aperture of stomata. In addition, the thylakoid membrane fluidity also plays an important role in their higher drought and salinity tolerance capability. The proteomic results further demonstrated that HSMR and DR facilitated the regulation of proteins associated with photosynthesis and energy metabolism, lipid metabolism, transcription and translation, and stress responses to well-adapt to the drought and salinity conditions. Overall, our results demonstrated that HSMR and DR shaped a similar adaption strategy from the structural and physiological levels to the molecular scale to ensure functionality in a harsh environment.

[A study on the online medical consulting websites based on the personal computer side]

Online medical consulting, acting as the primary type of Internet medical market, has been developing dramatically in the past ten years and begins to take shape. This study collected available information to describe service content status and service provider for online medical consulting websites. The current online medical consulting sites are mainly comprehensive medical consultation websites. The most common consulting provision from is combining graphics and text, which might not meet users' primary demand. The registered physicians are mostly the ones with junior position and work in the eastern and south-central parts of China. Activities of the registered physicians vary across the departments, but with extremely low initiatives.

Clone, expression and plasminogen binding property of three fructose-1,6-bisphosphate aldolases from Clonorchis sinensis

Fructose-1,6-bisphosphate aldolase (FbA), a well characterized glycometabolism enzyme, has been found to participate in other important processes besides the classic catalysis. To understand the important functions of three fructose-1,6-bisphosphate aldolases from Clonorchis sinensis (CsFbAs, CsFbA-1/2/3) in host-parasite interplay, the open reading frames of CsFbAs were cloned into pET30a (+) vector and the resulting recombinant plasmids were transformed into Escherichia coli BL21 (DE3) for expression of the proteins. Purified recombinant CsFbAs proteins (rCsFbAs) were approximately 45.0 kDa on 12% SDS-PAGE and could be probed with each rat anti-rCsFbAs sera by western blotting analysis. ELISA and ligand blot overlay indicated that rCsFbAs of 45.0 kDa as well as native CsFbAs of 39.5 kDa from total worm extracts and excretory-secretory products of Clonorchis sinensis (CsESPs) could bind to human plasminogen, and the binding could be efficiently inhibited by lysine analog ε-aminocaproic acid. Our results suggested that as both the components of CsESPs and the plasminogen binding proteins, three CsFbAs might be involved in preventing the formation of the blood clot so that Clonorchis sinensis could acquire enough nutrients from host tissue for their successful survival and colonization in the host. Our work will provide us with new information about the biological function of three CsFbAs and their roles in hostparasite interplay.

Virtual reality for acute and chronic pain management in adult patients: a narrative review

Virtual reality is a computer-generated environment that immerses the user in an interactive artificial world. This ability to distract from reality has been utilised for the purposes of providing pain relief from noxious stimuli. As technology rapidly matures, there is potential for anaesthetists and pain physicians to incorporate virtual reality devices as non-pharmacological therapy in a multimodal pain management strategy. This systematic narrative review evaluates clinical studies that used virtual reality in adult patients for management of acute and chronic pain. A literature search found 690 citations, out of which 18 studies satisfied the inclusion criteria. Studies were assessed for quality using the Jadad and Nottingham-Ottawa Scales. Agreement on scores between independent assessors was 0.87 (95%CI 0.73-0.94). Studies investigated virtual reality use: intra-operatively; for labour analgesia; for wound dressing changes; and in multiple chronic pain conditions. Twelve studies showed reduced pain scores in acute or chronic pain with virtual reality therapy, five studies showed no superiority to control treatment arms and in one study, the virtual reality exposure group had a worsening of acute pain scores. Studies were heterogeneous in: methods; patient population; and type of virtual reality used. These limitations suggest the evidence-base in adult patients is currently immature and more rigorous studies are required to validate the use of virtual reality as a non-pharmacological adjunct in multimodal pain management.

Expression and significance of miR-654-5p and miR-376b-3p in patients with colon cancer

BACKGROUND

The relationship between microRNAs, such as miR-654-5p and miR-376b-3p, and the prognosis of colon cancer has not been studied until now.

AIM

To evaluate the expression levels of miR-654-5p and miR-376b-3p and their clinical significance in colon cancer.

METHODS

RT-qPCR was performed to evaluate miR-654-5p and miR-376b-3p expression in 34 pairs of colon cancer and adjacent noncancerous tissues. Subsequently, the association of miR-654-5p and miR-376b-3p expression with clinical factors or the survival of patients suffering from colon cancer was determined by using The Cancer Genome Atlas.

RESULTS

miR-654-5p was upregulated and miR-376b-3p was downregulated in colon cancer tissues compared with adjacent noncancerous tissues (P < 0.001). Increased miR-654-5p and decreased miR-376b-3p expression levels were significantly associated with metastasis and clinical stage. Moreover, a univariate analysis demonstrated that colon cancer patients with high miR-654-5p or low miR-376b-3p expression (P = 0.044 and 0.007, respectively) had a poor overall survival rate. A multivariate analysis identified high miR-654-5p expression and low miR-376b-3p expression as independent predictors of poor survival in colon cancer patients.

CONCLUSION

Upregulated miR-654-5p and downregulated miR-376b-3p may be associated with tumour progression in colon cancer, and these microRNAs may serve as independent prognostic markers for colon cancer.

[The performance of visual photoscreening for Chinese preschool children aged 4 to 5 years]

Objective: To assess the accuracy of photoscreening for detecting refractive amblyopia risk factors (ARFs) in Chinese preschool children aged 4 to 5 years. Methods: A cross-sectional study. Comprehensive ocular examinations were conducted for preschool children in Nanjing, China from September to December, 2016. Photoscreening (Plusoptix A12C) was applied for refractive screening without cycloplegia. Voluntary children and children suspected of eyes abnormalities received cycloplegic retinoscopy (CR). Results of photoscreening and CR were compared using Wilcoxon signed rank test, and Bland-Altman plot were used to assess the agreement between the photoscreener and CR. According to the updated preschool vision screening guidelines from American Association for Pediatric Ophthalmology and Strabismus (AAPOS) in 2013, CR was adopted for identifying children with ARFs, which was considered as a golden standard. Based on the golden standard, the accuracy of 5 sets of referral criteria (including sensitivity standard, Matta/Silbert standard, AAPOS2013 standard, Alaska Blind Child Discovery standard, specificity standard) for photoscreener were tested. Receiver operating characteristics curves were constructed applied to evaluate the quality of the photoscreener in refractive ARFs detection and to find probably the best cut-off points. Results: In total, 1 986 children [mean age, (4.57±0.29) years] received comprehensive examinations, including 1 084 boys and 902 girls. The test ability of photoscreening was 99.04% (1 967/1 986) in the preschool children, and 96.56%(1 827/1 892) of the children got a reliable result within three screening attempts. In 538 children who had data of CR, refractive error of one child exceeded the upper limit of the photoscreener value setting, which was directly categorized as hyperopia, so in the end, 537 children were included to analyze the comparison between the two tests. The measurement values of photoscreening were lower than those of CR in sphere, cylinder and spherical equivalent [(0.75 (0.50, 1.25) D vs. 1.25 (1.00, 1.75) D, Z=-10.36, P<0.01; -0.50 (-0.75, -0.25) D vs. -0.25 (-0.75, 0.00) D, Z=-11.10, P<0.01; 0.63 (0.38, 0.88) D vs. 1.00 (0.75, 1.50) D, Z=-13.33, P<0.01]. The 95% limit of agreement cover rates between the photoscreening and CR in sphere, cylinder and spherical equivalent was 96.28% (517/537), 95.34% (512/537) and 96.65% (519/537), respectively. Based on the golden standard, 47 (8.74%) children had refractive ARFs, and the range of sensitivity, specificity, Youden index, positive predictive values and negative predictive values for detecting refractive ARFs of the 5 common used referral criteria was from 63.83% to 97.87%, from 53.36% to 97.56%, from 0.51 to 0.80, from 16.73% to 74.51% and from 96.57% to 99.62%, respectively. Considering particular refractive ARFs on the basis of the receiver operating characteristic curves, the optimal cut-off point for astigmatism was set at 1.38 D. Conclusion: Photoscreening could be an applicable tool to detect refractive ARFs in preschool children. (Chin J Ophthalmol, 2020, 56: 189-196).

[Effects of different fluid resuscitation methods on hemorheology in pigs during burn shock stage]

Objective: To investigate the impact of different methods of fluid resuscitation on hemorheology during burn shock stage. Methods: Twenty four miniature swines were randomly divided into four groups with 6 in each group (succinylated gelatin group, hydroxyethyl starch group, Parkland group and allogeneic plasma group). Severe burn shock model was established by burning miniature swine with napalm. Two hours after injury, succinylated gelatin, hydroxyethyl starch (130/0.4) and swine allogenic plasma were used as colloid (alternative colloid) in fluid resuscitation according to the burn shock fluid resuscitation formula which is commonly accepted in the field of Burns Surgery. In Parkland group, miniature swines received liquid recovery according to Parkland Formula. The vital signs before and within 48 h after burn were observed by Solar 8000i electrocardiomonitor during the process of transfusion. The infusion speed was adjusted based on the heart rate, blood pressure, urine volume and central venous pressure. The level of hematocrit (HCT), viscosity of plasma (ηp), index of rigidity (IR), red cell assembling index (RCA) and erythrocyte electrophoresis time (EFT) were measured at the time of pre-injury as well as 4, 8, 24 and 48 h post-injury and statistical analysis was performed. Results: HCT in hydroxyethyl starch group and Parkland group at 8 h post-injury were significantly higher than pre-injury [(0.395±0.047) vs (0.333±0.042), (0.379±0.026) vs (0.352±0.019)] (both P<0.05). And compared with pre-injury, HCT in hydroxyethyl starch (130/0.4) group at 48 h decreased significantly (0.232±0.021) vs (0.333±0.042) (P<0.05). HCT in Parkland group at 24, 48 h post-injury were lower than pre-injury [(0.277±0.021), (0.241±0.029) vs (0.352±0.019)] (both P<0.05). Compared with pre-injury, the levels of ηp in Parkland group decreased substantially at 4, 8 and 24 h post-injury [(1.61±0.07), (1.55±0.07) and (1.63±0.07) vs (1.73±0.04) mPa·s] (all P<0.05). Compared with allogeneic plasma group, IR decreased in succinylated gelatin group at 24, 48 h post-injury [(1.10±0.05 vs 1.26±0.07), (1.11±0.05 vs 1.32±0.05)](both P<0.05). RCA in succinylated gelatin group was significantly higher (both P<0.05) at 4 h (6.80±0.87) than pre-injury (5.92±0.43). RCA in hydroxyethyl starch group at 8 h post-injury (6.73±0.56) was significantly higher (both P<0.05) than pre-injury (6.03±0.53). Compared with pre-injury (17.3±1.3 s, 16.4±1.5 s), the levels of EFT in hydroxyethyl starch group (15.5±1.4 s) and Parkland group (13.4±1.2 s) decreased substantially at 48 h post-injury (both P<0.05). Compared with allogeneic plasma group, the level of EFT in succinylated gelatin group at 4 h post-injury (19.5±2.3 s) increased and decreased at 24 h post-injury (12.0±5.7 s) (both P<0.05). Conclusion: During swine burn shock stage, the hemorheological parameters of shock resuscitation with artificial colloid are more stable than those with Parkland formula resuscitation.

Comparison of tubeless percutaneous nephrolithotomy and standard percutaneous nephrolithotomy for kidney stones: A meta-analysis of randomized trials

This systematic review was designed to evaluate the efficacy of tubeless percutaneous nephrolithotomy (PCNL) versus standard percutaneous nephrolithotomy (PCNL) for kidney stones. Computerized search was performed for randomized clinical trials (RCTs) from PubMed, EMBASE, CENTRAL and Cochrane Database of Systematic Reviews databases. The included studies were randomized trials investigating tubeless PCNL versus standard PCNL in patients with kidney stones. Outcomes measured included postoperative pain, postoperative analgesia, hospital stay, drop in hemoglobin, stone free, urine leakage, blood transfusion, or pyrexia per randomized patients. In all, 15 RCTs involving 947 subjects were included. With regard to postoperative pain, analgesia, hospital stay and urine leakage, it was significantly reduced in tubeless PCNL group. In respect of drop in hemoglobin, stone free, blood transfusion and pyrexia, tubeless PCNL group appeared to be equivalent with standard PCNL group. Tubeless PCNL technology is associated with shorter hospitalization time, lower incidence of postoperative pain and less analgesia requirement after nephrolithotony. Tubeless PCNL can be used as a substitute for traditional standard PCNL of the first-line treatment. Nevertheless, further research in this field is urgently needed to confirm it.

miR-192 Is Overexpressed and Promotes Cell Proliferation in Prostate Cancer

OBJECTIVE

Prostate cancer (PCa) is one of the most prevalent types of cancer among men worldwide. The incidence of PCa is increasing in China. Therefore, there is an urgent need to identify novel diagnostic and prognostic markers for PCa to improve the treatment of the disease.

METHODS

The Cancer Genome Atlas (TCGA) and GEO database were used to analyze the expression of miR-192, and the relationship between miR-192 and the clinical features of patients with PCa. Cell cycle and cell proliferation assay were used to detect the functional roles of miR-192 in PCa. Bioinformatic analysis for miR-192-5p was performed using gene ontology and KEGG analysis.

RESULTS

By analyzing the dataset of TCGA, we found that miR-192 was overexpressed in PCa samples compared to normal tissues and was upregulated in high-grade PCa compared to low-grade PCa. We also observed that higher miR-192 expression was associated with a shorter biochemical recurrence-free survival time. Our results also demonstrated that miR-192 promoted PCa cell proliferation and cell cycle progression.

CONCLUSION

These results suggest that miR-192 may be considered for use as a potential diagnostic and therapeutic target of PCa.

Identification and characterization of probiotic yeast isolated from digestive tract of ducks

The objective of this study was to isolate and identify yeast strains from the digestive tract of ducks, and evaluate in vitro their potential as probiotics in poultry. The yeast strains were isolated using malt extract agar medium, and identified through morphological, physiological, and biochemical tests as well as sequence homology analyses of 26S rDNA D1/D2 region. A total of 35 yeast strains were isolated from the guts of Cherry Valley meat ducks, including seven strains of Saccharomyces cerevisiae (S. cerevisiae). These seven strains of S. cerevisiae were further screened for their use as alternative yeast probiotics strains for poultry feed. The yeast strains were characterized for their cell surface hydrophobicity, autoaggregation ability, and resistance to high temperature (30°C, 37°C, and 42°C), low pH (2.0, 3.0, and 4.0), bile salts (0.3% and 0.6%), and nutrition starvation (2, 4, 6, 8, 10, and 12 days). The isolates of WHY-2 and WHY-7 had a higher survival percentage at 37°C, pH 2.0, 0.60% poultry bile salts, and 10 days of nutrition starvation, with higher cell surface hydrophobicity and autoaggregation, when compared with the other isolates, suggesting that the isolates WHY-2 and WHY-7, could be used as probiotic candidates. The data obtained in this study could help in selecting probiotic yeast candidates for use in poultry industry.

[The analysis of clinical characteristics and disease activity in ankylosing spondylitis patients with hyperuircemia]

Objective: to investigate the clinical characteristics and disease activity in ankylosing spondylitis (AS) patients with hyperuricemia. Method: Laboratory tests, magnetic resonance imaging, disease activity and functional index of AS patients from Fudan University Zhongshan Hospital were collected. T test, square test were applied to investigate the difference between AS patients with hyperuricemia and AS patients with normal serum uric acid in clinical characteristics and disease activity in AS patients. Result: Among all the AS patients, 23.4% (22/94) patients accompanied with hyperuricemia. AS patients accompanied with hyperuricemia showed significant younger age (28.9±7.9 vs 35.8±11.1, P=0.002); higher serum alanine aminotransferase (33.6±23.6 vs 19.8±12.4, P=0.014), aspartate aminotransferase (23.8±8.7 vs 18.6±9.6, P=0.025) and creatinine (78.4±12.5 vs 69.8±13.3, P=0.009), lower Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) (11.2±8.8 vs 17.9±12.0, P=0.027) and Bath Ankylosing Spondylitis Functional Index (BASFI) (0.7±0.9 vs 1.8±2.2, P=0.002) compared with AS patients whose serum uric acid level is normal. Conclusion: AS Patients with younger age, impaired hepatic and renal funtion and lower scores in BASDAI and BASFI tend to accompany with hyperuricemia.

Silencing of RTKN2 by siRNA suppresses proliferation, and induces G1 arrest and apoptosis in human bladder cancer cells

Human bladder cancer is the most common urological malignancy in China. One of the causes of carcinogenesis in the cancer may be gene mutation. Therefore, the present study investigated the expression levels of Rhotekin 2 (RTKN2), a Rho effector protein, in human bladder cancer tissues and cell lines, and examined the effect of RTKN2 on the proliferation, cell cycle, apoptosis and invasion of human bladder cancer cell lines. The mRNA expression levels of RTKN2 in 30 human bladder cancer tissue samples were significantly higher, compared with those in 30 normal human bladder tissue samples. The protein expression levels of RTKN2 was markedly higher in T24 and 5637 cells, compared with those in four other human bladder cancer cell lines. The silencing of RTKN2 by small interfering (si)RNA inhibited cell proliferation and arrested cell cycle at the G1 phase, via reducing the expression levels of the MCM10, CDK2, CDC24A and CDC6 cell cycle‑associated proteins in the T24 and 5637 cells. Furthermore, RTKN2 knockdown in the cells led to cell apoptosis and the suppression of invasion. These results suggested that RTKN2 is involved in the carcinogenesis and progression of human bladder cancer, indicating that RTKN2 may be a molecular target in cancer therapy.

Utilization of excess NADH in 2,3-butanediol-deficient Klebsiella pneumoniae for 1,3-propanediol production

AIMS

To utilize excess NADH for 1,3-propanediol production by 2,3-butanediol-deficient mutants, the effect of dhaT overexpression in two distinct 2,3-butanediol-deficient mutants was investigated.

METHODS AND RESULTS

Two 2,3-butanediol-deficient mutants, KG1-3 (blocking of the 2,3-butanediol pathway only) and KG1-5 (blocking of both of 2,3-butanediol and lactate pathways) were constructed. Our results showed that although the intracellular redox balance (NADH/NAD(+)) was extremely high at the end of fermentation for both mutants, the status of intracellular redox in KG1-5 was maintained at a normal level following the first stage of fermentation. Analysis of cell growth and metabolite formation confirmed the inhibition of excess lactate in 2,3-butanediol pathway-deficient mutants. Furthermore, dhaT was overexpressed in two 2,3-butanediol-deficient mutants (KG1-3T and KG1-5T). In KG1-5T, the intracellular redox balance was restored to normal and 1,3-propanediol production increased. The yield of 1,3-propanediol from glycerol in KG1-5T was also restored to a normal level of 0·6.

CONCLUSIONS

The excess NADH in both the 2,3-butanediol- and lactate-deficient mutants can be used by overexpresstion of dhaT.

SIGNIFICANCE AND IMPACT OF STUDY

The metabolic flux tended to increase lactate production by the abolishment of the 2,3-butanediol pathway in Klebsiella pneumoniae, and the high accumulation of lactate prevented the cell from using excess NADH, thereby inhibiting cell growth and 1,3-propanediol production.

Identification of pheromone components and their binding affinity to the odorant binding protein CcapOBP83a-2 of the Mediterranean fruit fly, Ceratitis capitata

The Mediterranean fruit fly (or medfly), Ceratitis capitata (Wiedemann; Diptera: Tephritidae), is a serious pest of agriculture worldwide, displaying a very wide larval host range with more than 250 different species of fruit and vegetables. Olfaction plays a key role in the invasive potential of this species. Unfortunately, the pheromone communication system of the medfly is complex and still not well established. In this study, we report the isolation of chemicals emitted by sexually mature individuals during the "calling" period and the electrophysiological responses that these compounds elicit on the antennae of male and female flies. Fifteen compounds with electrophysiological activity were isolated and identified in male emissions by gas chromatography coupled to electroantennography (GC-EAG). Within the group of 15 identified compounds, 11 elicited a response in antennae of both sexes, whilst 4 elicited a response only in female antennae. The binding affinity of these compounds, plus 4 additional compounds known to be behaviourally active from other studies, was measured using C. capitata OBP, CcapOBP83a-2. This OBP has a high homology to Drosophila melanogaster OBPs OS-E and OS-F, which are associated with trichoid sensilla and co-expressed with the well-studied Drosophila pheromone binding protein LUSH. The results provide evidence of involvement of CcapOBP83a-2 in the medfly's odorant perception and its wider specificity for (E,E)-α-farnesene, one of the five major compounds in medfly male pheromone emission. This represents the first step in the clarification of the C. capitata and pheromone reception pathway, and a starting point for further studies aimed towards the creation of new powerful attractants or repellents applicable in the actual control strategies.

Identification and Expression Profile of Two Putative Odorant-Binding Proteins from the Neotropical Brown Stink Bug, Euschistus heros (Fabricius) (Hemiptera: Pentatomidae)

This work presents the first identification of putative odorant-binding proteins (OBPs) from a member of the Pentatomidae, i.e. the brown stink bug Euschistus heros (Fabricius), an important pest of soybean in Brazil. Antennae from both sexes of E. heros adults (12 days old and unmated) were used to construct a cDNA library, from which two transcripts encoding putative E. heros OBPs (EherOBPs) were identified. The expression levels of EherOBP1 and EherOBP2 were found to be higher in male antennae than in female and there was difference in expression in legs, wings, and abdomens of the two sexes. The histolocalization of EherOBP1 and EherOBP2 transcripts in antennae also showed a sexual dimorphism in the chemoreception system, with different expression sites in the antennal segments between males and females, occurring predominantly at the base of the sensillum. The implications of these findings for stink bug chemoreception are discussed.

PKA phosphorylation reshapes the pharmacological kinetics of BmK AS, a unique site-4 sodium channel-specific modulator

Although modulation of the activity of voltage-gated sodium channels (VGSCs) by protein kinase A (PKA) phosphorylation has been investigated in multiple preparations, the pharmacological sensitivity of VGSCs to scorpion toxins after PKA phosphorylation has rarely been approached. In this study, the effects of BmK AS, a sodium channel-specific modulator from Chinese scorpion Buthus martensi Karsch, on the voltage-dependent activation and inactivation of Nav1.2 were examined before and after PKA activation. After PKA phosphorylation, the pattern of dose-dependent modulation of BmK AS, on both Nav1.2α and Nav1.2 (α + β1) was reshaped. Meanwhile, the shifts in voltage-dependency of activation and inactivation induced by BmK AS were attenuated. The results suggested that PKA might play a role in different patterns how β-like toxins such as BmK AS modulate gating properties and peak currents of VGSCs.

Analysis of antigen epitopes and molecular pathogenic characteristics of the 2009 H1N1 pandemic influenza A virus in China

In order to further predict the epidemic trend and develop vaccines for 2009 H1N1 virus, we monitored its epitopes and molecular pathogenic characteristics during the epidemic process. We also analyzed the similarity of antigenic and genetic characteristics among the novel 2009 H1N1, representative seasonal H1N1 strains, and vaccine strains. 2009 H1N1 isolates had high similarity of hemagglutinin (HA) antigenic sites with H1N1 viruses isolated before 1940 and up to 80.0% similarity with 1918 H1N1. The elderly people born before 1940 have relatively low 2009 H1N1 infection rate, which might be responsible for their previous infection with either 1918 H1N1 virus or an early progeny. Compared to seasonal H1N1 vaccine strains from 1999 to 2010, the HA, neuraminidase (NA), and nucleoprotein (NP) proteins of the isolates had highly conserved CTL epitopes (60.5-65.8%, 69.6-82.6%, and 76.7%, respectively). The seriousness and mortality rate of 2009 H1N1 infections were similar to seasonal influenza, which may be related to the molecular characteristics of low toxicity of 2009 H1N1 and cross-T-cell immunity, due to vaccination or exposure to seasonal H1N1 virus. Some strains of 2009 H1N1 acquired mutations at antigenic and glycosylation sites. It is of particular interest that Haishu/SWL110/10 and Beijing/SE2649/09, isolated after November 2009, gained a new glycosylation site at the position 179 of HA protein, near the RBD. Thus, in the future, vaccination with glycosylated 2009 H1N1 virus may prevent the seasonal epidemic caused by strains with glycosylation site mutation near the receptor binding domain (RBD).

Dissecting prenatal, postnatal, and inherited effects: ART and design

With the failure of common variants alone to explain the bulk of trait heritability, it becomes more important to understand the contribution of maternally inherited effects, prenatal effects, and postnatal environmental effects. These effects can be disentangled by studying families containing children conceived by assisted reproductive technologies (ART). We propose and develop a model that is an extension of the variance component model commonly used in pedigree analysis. Our model is flexible enough to allow any number of family members and degrees of relationship; thus, researchers can use both small and extended families simultaneously. Simulations demonstrate that our method has appropriate statistical properties and is robust to model misspecification and accurate in the presence of missing data. Most importantly, our method is able to disentangle maternally inherited effects from prenatal effects, which are confounded in traditional family studies. Our analyses also provide guidance to researchers designing studies that will use ART families to clarify genetic and environmental factors underlying traits.

Protein kinase C-epsilon is a trigger of delayed cardioprotection against myocardial ischemia of kappa-opioid receptor stimulation in rat ventricular myocytes

Kappa-opioid receptor (OR) stimulation with a selective agonist, U50,488H (U50), known to mediate the delayed cardioprotection of metabolic inhibition preconditioning (MIP) against cell injury/death in rat ventricular myocytes, has been shown to act via protein kinase C (PKC). We attempted to identify the PKC isoform(s) that is activated, thus triggering delayed cardioprotection of MIP and pretreatment with 10 microM U50 (U50 pretreatment, UP). Release of lactate dehydrogenase and exclusion of trypan blue by isolated rat ventricular myocytes were used as indices of cell injury and death, respectively. Both MIP and UP induced translocation of PKC-epsilon, but not other PKC isoforms, -alpha and -delta, from cytosolic to membrane fractions. This was accompanied by reductions in cell injury/death induced by lethal simulated ischemia. The effects of MIP and UP were attenuated and abolished by 1 microM nor-binaltorphimine, a selective kappa-OR antagonist, administered before and during preconditioning/pretreatment, respectively. The effects were mimicked by 10 nM phorbol-12-myristate-13-acetate, a PKC activator, but attenuated by 5 microM chelerythrine, a PKC inhibitor. More importantly, 0.1 microM epsilonV1-2, a selective PKC-epsilon inhibitor administered before and during MIP/UP, also attenuated the effects of both treatments on cell injury/death and translocation of PKC-epsilon. On the other hand, 5 microM rottlerin, a selective PKC-delta inhibitor, did not alter the effects of either treatment on injury/death. The results indicate that both MIP and UP activate PKC-epsilon, leading to delayed cardioprotection in rat ventricular myocytes.

Relationship between lactone ring forms of HCPT and their antitumor activities

AIM

To study the relationship between the lactone forms of 10-hydroxycamptothecin (HCPT) and their antitumor activities.

METHODS

Antitumor activity of the two forms of HCPT was studied in vitro using seven cultured human and mouse tumor cell lines. Mice bearing sarcoma 180 and solid hepatoma were treated with HCPT (0.5, 1, and 2 mg/kg, ip) and tumor growth inhibition was assayed. HPLC method was employed to investigate the conversion of two forms of HCPT in different pH conditions and cultured tumor cells.

RESULTS

It was found that both forms of HCPT (O-HCPT and C-HCPT) showed similar activities in vitro against a number of tumor cell lines at the same concentration; but C-HCPT was more effective (about two times) than O-HCPT in vivo. The difference between in vitro and in vivo results could be explained by the conversion of O-HCPT into C-HCPT in a certain condition, which was shown by the HPLC analysis of HCPT at different pH values and in cultured tumor cells.

CONCLUSION

Both forms of HCPT were effective against tumor growth, but C-HCPT was more effective than O-HCPT, the latter could be converted into the former under certain conditions.

Inducible HSP70 mediates delayed cardioprotection via U-50488H pretreatment in rat ventricular myocytes

To test the hypothesis that heat-shock proteins (HSPs) mediate delayed cardioprotection of prior kappa-opioid receptor (kappa-OR) stimulation, we first correlated cellular injury and viability with the expression of HSP70s in isolated rat ventricular myocytes subjected to prior kappa-OR stimulation with the selective agonist trans-(+/-)-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzeneacetamide (U-50488H) and delayed lethal simulated ischemia (LSI). Cell injury and viability were indicated by lactate dehydrogenase release and trypan blue exclusion, respectively. The reduced injury and increased viability after pretreatment with U-50488H were concentration dependent and correlated directly with the expression of both stress-inducible (HSP70) and constitutive (HSC70) proteins. The effects mimic those with metabolic inhibition preconditioning (MIP). The cardioprotection against LSI by pretreatment with U-50488H and MIP was abolished and antagonized, respectively, via blockade of the kappa-OR by its selective antagonist, nor-binaltorphimine. We also found that blockade of the production of HSP70 but not HSC70 blocked the inhibitory effect of pretreatment with U-50488H on injury and viability. These observations provide evidence that stress-inducible HSP70 mediates delayed cardioprotection of prior kappa-OR stimulation.

PEGylated recombinant human tumor necrosis factor alpha: preparation and anti-tumor potency

AIM

To assess the merits of polyethylene glycol-modified recombinant human tumor necrosis factor alpha (PEG-rHuTNF-alpha).

METHODS

The rHuTNF-alpha was modified with N-succinimidyl succinate monomethoxy polyethylene glycol (SS-PEG) of three different molecular weights. The PEG-rHuTNF-alpha was separated into fractions of various molecular weights by gel filtration chromatography. In vitro activities of various fractions were determined with L929 cell assay and in vivo anti-tumor potencies of main fractions were studied with respect to necrosis of S-180 solid tumor.

RESULTS

The rHuTNF-alpha could be modified using SS-PEG under mild conditions. The main fraction of PEG5000-rHuTNF-alpha contained four PEG molecules, and PEG12000-rHuTNF-alpha and PEG20000-rHuTNF-alpha contained two PEG molecules, respectively. There was a higher activity when rHuTNF-alpha was coupled to less numbers of the same molecular weight PEG molecules. When PEG-rHuTNF-alpha was of the same molecular weight, rHuTNF-alpha modified with bigger molecular weight PEG molecules had a higher activity. PEG-rHuTNF-alpha was resistant to proteolysis, and over 70 % activity remained after 8 h, but the activity of rHuTNF-alpha was time-dependently diminished by incubation with bovine trypsin. PEG5000-rHuTNF-alpha (1500 IU per mouse) had a similar anti-tumor potency compared with rHuTNF-alpha (3000 IU per mouse). PEG12000-rHuT NF-alpha (1500 IU per mouse) had an increased anti-tumor potency compared with rHuTNF-alpha (3000 IU per mouse). In particular, PEG20000-rHuTNF-alpha at a dose of 1500 IU per mouse had a higher anti-tumor potency than rHuTNF-alpha at a dose of 6000 IU per mouse.

CONCLUSION

PEG-modified rHuTNF-alpha could be more suitable for therapeutic use

Stealth polycyanoacrylate nanoparticles as tumor necrosis factor-alpha carriers: pharmacokinetics and anti-tumor effects

The objective of this study was to investigate the pharmacokinetics and in vivo anti-tumor effect of recombinant human tumor necrosis factor-alpha (rHuTNF-alpha) encapsulated in poly(methoxypolyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEG-PHDCA) nanoparticles. Our experimental results showed that PEG-PHDCA nanoparticles could extend the half-life of rHuTNF-alpha to 7.42 h and obviously change the protein biodistribution in tissues, and in particular, increase accumulation of rHuTNF-alpha in tumor. Compared with PHDCA nanoparticles and free rHuTNF-alpha, PEG-PHDCA nanoparticles loaded with rHuTNF-alpha showed higher antitumor potency at the same dose, which might be related to its higher accumulation in tumor tissues and longer plasma circulation time. Therefore, PEG-PHDCA nanoparticles could be an effective carrier for rHuTNF-alpha.

PEGylated polycyanoacrylate nanoparticles as tumor necrosis factor-alpha carriers

The aim of this study was to find an effective carrier for recombinant human tumor necrosis factor-alpha (rHuTNF-alpha). The influence of solvent systems containing poly(methoxy-polyethyleneglycol cyanoacrylate-co-n-hexadecyl cyanoacrylate) (PEGylated PHDCA) on the biological activity of rHuTNF-alpha was investigated. The PEGylated PHDCA nanoparticles loading rHuTNF-alpha were prepared with the double emulsion method. The influence of main experimental factors on the entrapment efficiency was evaluated by the Uniform Design. The physicochemical characteristics and in vitro release of rHuTNF-alpha from the nanoparticles were determined. The results showed that serum albumin such as human serum albumin (HSA) or bovine serum albumin (BSA) could play a protective action on rHuTNF-alpha in the preparation process. At > or =2.0% (w/v) HSA concentration, more than 85% of rHuTNF-alpha activity remained and the role of HSA was not affected by copolymer concentrations from 0.5 to 3.0% (w/v). The entrapment efficiency of the nanoparticles was about 60% and the nanoparticle size was about 150 nm. The nanoparticles were spherical in shape and uniform with the value of the zeta potential about -9 mV. The rHuTNF-alpha release from the nanoparticle showed an initial burst and then continued in a sustained fashion. The results showed that the PEGylated PHDCA nanoparticles could be an effective carrier for rHuTNF-alpha.

A high affinity fungal nitrate carrier with two transport mechanisms

We have expressed the CRNA high affinity nitrate transporter from Emericella (Aspergillus) nidulans in Xenopus oocytes and used electrophysiology to study its properties. This method was used because there are no convenient radiolabeled substrates for the transporter. Oocytes injected with crnA mRNA showed nitrate-, nitrite-, and chlorite-dependent currents. Although the gene was originally identified by chlorate selection there was no evidence for transport of this anion. The gene selection is explained by the high affinity of the transporter for chlorite, and the fact that this ion contaminates solutions of chlorate. The pH-dependence of the anion-elicited currents was consistent with H(+)-coupled mechanism of transport. At any given voltage, currents showed hyperbolic kinetics with respect to extracellular H(+), and these data could be fitted with a Michaelis-Menten relationship. But this equation did not adequately describe transport of the anion substrates. At higher concentrations of the anion substrates and more negative membrane voltages, the currents were decreased, but this effect was independent of changes in external pH. These more complicated kinetics could be fit by an equation containing two Michaelis-Menten terms. The substrate inhibition of the currents could be explained by a transport reaction cycle that included two routes for the transfer of nitrate across the membrane, one on the empty carrier and the other proton coupled. The model predicts that the substrate inhibition of transporter current depends on the cytosolic nitrate concentration. This is the first time a high affinity nitrate transport activity has been characterized in a heterologous system and the measurements show how the properties of the CRNA transporter are modified by changes in the membrane potential, external pH, and nitrate concentration. The physiological significance of these observations is discussed.

Impaired G(s)alpha and adenylyl cyclase cause beta-adrenoceptor desensitization in chronically hypoxic rat hearts

The effects of beta-adrenoceptor stimulation with isoproterenol on electrically induced contraction and intracellular calcium ([Ca(2+)](i)) transient, and cAMP in myocytes from both hypertrophied right and nonhypertrophied left ventricles of rats exposed to 10% oxygen for 4 wk, were significantly attenuated. The increased [Ca(2+)](i) transient in response to cholera toxin was abolished, whereas increased cAMP after NaF significantly attenuated. The biologically active isoform, G(s)alpha-small (45 kDa), was reduced while the biologically inactive isoform, G(s)alpha-large (52 kDa), increased. The increased electrically induced [Ca(2+)](i) transient and cAMP with 10-100 microM forskolin were significantly attenuated in chronically hypoxic rats. The content of G(i)alpha(2), the predominant isoform of G(i) protein in the heart, was unchanged. Results indicate that impaired functions of G(s) protein and adenylyl cyclase cause beta-adrenoceptor desensitization. The impaired function of the G(s) protein may be due to reduced G(s)alpha-small and/or increased G(s)alpha-large, which does not result from changes in G(i) protein. Responses to all treatments were the same for right and left ventricles, indicating that the impaired cardiac functions are not secondary to cardiac hypertrophy.

Impaired [Ca(2+)](i) and pH(i) responses to kappa-opioid receptor stimulation in the heart of chronically hypoxic rats

kappa-Opioid receptor (kappa-OR) stimulation with U50,488H, a selective kappa-OR agonist, or activation of protein kinase C (PKC) with 4-phorbol 12-myristate 13-acetate (PMA), an activator of PKC, decreased the electrically induced intracellular Ca(2+) ([Ca(2+)](i)) transient and increased the intracellular pH (pH(i)) in single ventricular myocytes of rats subjected to 10% oxygen for 4 wk. The effects of U50,488H were abolished by nor-binaltorphimine, a selective kappa-OR antagonist, and calphostin C, a specific inhibitor of PKC, while the effects of PMA were abolished by calphostin C and ethylisopropylamiloride (EIPA), a potent Na(+)/H(+) exchange blocker. In both right hypertrophied and left nonhypertrophied ventricles of chronically hypoxic rats, the effects of U50,488H or PMA on [Ca(2+)](i) transient and pH(i) were significantly attenuated and completely abolished, respectively. Results are first evidence that the [Ca(2+)](i) and pH(i) responses to kappa-OR stimulation are attenuated in the chronically hypoxic rat heart, which may be due to reduced responses to PKC activation. Responses to all treatments were the same for right and left ventricles, indicating that the functional impairment is independent of hypertrophy. kappa-OR mRNA expression was the same in right and left ventricles of both normoxic and hypoxic rats, indicating no regional specificity.

Xenopus oocytes as an expression system for plant transporters

The Xenopus oocyte provides a powerful system for the expression and characterisation of plant membrane proteins. Many different types of plant membrane proteins have been expressed and characterised using this system. As there are already several general reviews on the methodology for oocyte expression of channel proteins, we have summarised the particular advantages and disadvantages of using the system for the characterisation of plant cotransporter proteins. As an example of how the system can be used to identify transporters, we describe evidence for a low affinity nitrate transporter in oocytes injected with poly(A) RNA extracted from nitrate-induced barley roots. Furthermore, we describe evidence that the expression of some transporters in oocytes can modify the properties of endogenous membrane proteins. We conclude that although care must be taken in the interpretation of results and in choosing appropriate controls for experiments, oocyte expression is an excellent tool which will have an important role in characterising plant membrane proteins.

A high affinity nitrate transport system from Chlamydomonas requires two gene products

A nitrate-regulated cluster of genes involved in nitrate transport and assimilation has been identified in Chlamydomonas reinhardtii. Mutant strains of the alga, which are defective in some aspect of transport and assimilation have been used to assign functions to these genes. This analysis has suggested that two gene products are necessary to obtain a functional high affinity nitrate system in Chlamydomonas [Quesada et al. (1994) Plant J. 5, 407-419]. In this paper we have tested this hypothesis by injecting Xenopus oocytes with mRNA prepared from these two cDNAs, Nrt2;1 and Nar2, and then assaying the oocytes for nitrate transport activity. Oocytes injected with single types of mRNA did not show any nitrate transport activity. Furthermore, Nar2 mRNA was toxic to oocytes, with nearly 60%, of the oocytes dead 3 days after the injection. However, when oocytes were injected with a mixture of two mRNAs prepared from Nrt2;1 and Nar2, a high affinity nitrate transport activity could be measured. However, the Km for nitrate of this transport system was 28 microM which is higher than the value of 1.6 microM which had been obtained by the analysis of mutant phenotypes. The pH-dependence of the nitrate-elicited currents was consistent with a proton-cotransport mechanism. These results prove that two gene products are required to produce a functional high affinity nitrate transport system and that this process does not involve transcriptional regulation.

Pharmacokinetics of intragastric ipriflavone solid dispersion in rats

AIM

To evaluate pharmacokinetic behavior of ipriflavone solid dispersion in rats.

METHODS

The plasma concentrations of ipriflavone in rats were determined by HPLC with UV detector.

RESULTS

Plasma concentration-time curves after ig ipriflavone solid dispersion 250 mg.kg-1 in rats were fitted with one-compartment model. Pharmacokinetic parameters were as follows: Ke = 0.21 h-1, T1/2Ke = 5.19 h, Ka = 1.71 h-1, T1/2Ka = 0.41 h, Tmax = 0.67 h, Cmax = 429 micrograms.L-1, AUC = 3916 micrograms.h.L-1; The relative bioavailability of ipriflavone solid dispersion was 323%.

CONCLUSION

Ipriflavone in solid dispersion was absorbed more effectively than that in physical mixture in rats.

Preparation and dissolution property of ipriflavone solid dispersion

AIM

To prepare and identify ipriflavone (IP) solid dispersion, and determine its dissolution property.

METHODS

The solvent method was used for preparation and differential scanning calorimetry (DSC), X-ray diffraction and infrared spectrophotometry for identification of IP solid dispersion. The dissolution of the dispersion was determined with paddle method.

RESULTS

The dissolution of IP solid dispersion consisting of IP and povidone-k30 (PVP) (1:8) in artificial gastric juice is 6.15 times as high as that of IP alone. The DSC curves, X-ray diffraction patterns and infrared spectrophotometries of IP have been changed obviously by the dispersion.

CONCLUSION

The dissolution of IP is increased by solid dispersion method.

Cloning and functional characterization of a Brassica napus transporter that is able to transport nitrate and histidine

A full-length cDNA for a membrane transporter was isolated from Brassica napus by its sequence homology to a previously cloned Arabidopsis low affinity nitrate transporter. The cDNA encodes a predicted protein of 589 amino acid residues with 12 putative transmembrane domains. The transporter belongs to a multigene family with members that have been identified in bacteria, fungi, plants, and animals and that are able to transport a range of different nitrogen-containing substrates, including amino acids, peptides, and nitrate. To identify the substrates of this plant gene, we have expressed the protein in Xenopus oocytes. The properties of the transporter are consistent with a proton cotransport mechanism for nitrate, and the voltage dependence of the Km for nitrate was determined. The Km for nitrate was shown to increase from 4 to 14 mM as the membrane voltage became more negative from -40 to -180 mV. Oocytes expressing the gene could accumulate internal nitrate to concentrations higher than those measured in water-injected controls. A range of different substrate molecules for the transporter was tested, but of these, histidine gave the largest currents, although the affinity was in the millimolar range. The pH dependence of the activity of the transporter was different for the substrates, with histidine transport favored at alkaline and nitrate at acid external pH. Kinetic analysis of the mechanism of histidine transport suggests a cotransport of protons and the neutral form of the amino acid, with the Km for histidine decreasing at more negative membrane voltages. This gene is the first member of this family of transporters for which the transport of two very different types of substrate, nitrate and histidine, has been demonstrated.

4-substituted cubylcarbinylamines: a new class of mechanism-based monoamine oxidase B inactivators

Cubylcarbinylamine (1a), (4-cyclopropylcubyl)carbinylamine (1b), and (4-phenylcubyl)carbinylamine (1c) were synthesized and shown to be time-dependent, irreversible inactivators of monoamine oxidase B (MAO B). Substrate protects the enzyme from inactivation, but beta-mercaptoethanol does not, suggesting that these compounds are mechanism-based inactivators. All three compounds were also substrates for MAO B with partition ratios ranging from 152 to 536. The 4-substituted analogues were more potent inactivators than the unsubstituted analogue, indicating a benefit to 4-substitution in this class of inactivators.

Direct continuous fluorometric assay for monoamine oxidase B

The first direct and continuous fluorometric assay for monoamine oxidase B (MAO B) has been developed. E-2,5-Dimethoxycinnamylamine hydrochloride was designed and synthesized and was found to be an excellent substrate for MAO B (Km = 218 microM, Kcat = 435 min-1). This compound has an intense purple fluorescence when irradiated at lambda ex = 343 nm (lambda em = 393 nm) in Tris buffer, pH 9.0, or sodium phosphate buffer, pH 7.2, but under the same conditions, the corresponding aldehyde, the product of the MAO-catalyzed oxidation of E-,5-dimethoxycinnamylamine hydrochloride, does not fluoresce. The activity of MAO B, therefore, can be determined efficiently and rapidly by continuously following the decrease in fluorescence at 393 nm at enzyme concentrations as low as 100 nM. The change in fluorescence is linear up to a substrate concentration of 500 microM.

Effects of a Dan Shen component, magnesium lithospermate B, in nephrectomized rats

Magnesium lithospermate B, a compound newly isolated from Dan Shen, was given orally to rats for 70 days after excision of five-sixths of their kidney volume. As a result, mesangial proliferation, tubulo-interstitial lesions and glomerular sclerotic lesions, which were conspicuous in rats that were not given magnesium lithospermate B after nephrectomy, were inhibited. Furthermore, a decrease in blood urea nitrogen, improvement of hypoproteinemia, hypoalbuminemia and hypercholesteremia, and inhibition of urinary protein excretion were observed. The levels of creatinine, methylguanidine and guanidino-succinic acid, which accumulate in the blood with the progress of renal failure, were decreased significantly in rats given magnesium lithospermate B. These results indicate that magnesium lithospermate B, a component of an Oriental medicine has potential as a new therapeutic agent for inhibiting the progression of renal dysfunction.

Effects of ginseng in nephrectomized rats

Ginseng extract and its active component, saponin, were administered orally to nephrectomized rats for 90 d, and changes in blood and urine parameters and renal tissue lesions were assessed. Rats given saponin showed a significant decrease in the concentrations of blood urea nitrogen, creatinine and methylguanidine and a significant increase in total protein and albumin in the blood, with reduce urinary excretion of protein. There was also slight amelioration of the degree of mesangial proliferation, the severity of extratubular lesions and glomerular sclerotic lesions, and the extent of tubular interstitial lesions. However, these histological changes were inconspicuous in nephrectomized rats given ginseng extract.

[Characterization of a fluorouracil-resistant human gastric carcinoma cell line and its morphological behavior]

A fluorouracil (FU)-resistant human carcinoma cell line (SGC-7901/R) was established in culture by progressively increasing the concentration of FU from 50 ng.ml-1 to 2.5 mg.ml-1. The cell line has been successfully subcultured for more than 150 passages during more than 2 years. Its degree of FU resistance was 139-fold vs that of FU sensitive cell line (SGC-7901/S), and the resistant phenotype was stable when cells were cultured for 23 passages in FU-free medium. The doubling time was 17.3 and 25.6 h for resistant cells and parental cells, respectively. Swiss (nu/nu) nude mice were used for the in vivo experiment, the FU-resistant cell line also exhibited resistance to FU and cross-resistance to mitomycin C. FU inhibited markedly the incorporation of [3H]UR into sensitive cells and only showed a 31.6% inhibition with FU 100 micrograms.ml-1 in resistant cells. For the incorporation of [3H]TdR into DNA, inhibitory rates were seen with different concentrations of FU in resistant cells. By morphologic observation, SGC-7901/R cells showed little secretion but without any tendency to glandular pattern. Their nuclei were allotype with enlarged perinuclear space and a few intranuclear pseudoinclusions. The mitotic phase of cells was found frequently. The phenotype of resistant cell line can be deduced more malignant than that of parental cell line.