Professional identity, job satisfaction, and turnover intention among Chinese novice nurses: A cross-sectional study

The world is faced with challenges due to a growing aging population and the increasing burden of chronic disease. The acute shortage of nurses and high turnover rates, particularly among novice nurses, are of great concern in many countries. Several studies have shown that turnover intention among nurses is influenced by professional identity and job satisfaction. However, to the best of our knowledge, no studies have examined this issue in the context of novice nurses. Thus, the present study aimed to explore the relationship between professional identity, job satisfaction, and turnover intention among novice nurses in China. From March 18 to April 23, 2022, a cross-sectional survey was carried out involving 532 novice nurses recruited from four public hospitals in Sichuan Province, China. Among the sample, 526 questionnaires were retrieved, with an effective response rate of 98.87%. The mean scores for turnover intention, professional identity, and job satisfaction were 13.02 ± 3.94, 36.17 ± 7.98, and 111.02 ± 21.46, respectively. High turnover intention was observed among novice nurses, of whom 54.37% (286/526) had high or very high turnover intention. Professional identity and job satisfaction among novice nurses were moderate. In terms of demographic characteristics, "Whether living with relatives" and "Monthly income" had a statistically significant impact on the turnover intention of novice nurses (P < .05). Both professional identity (r = -0.459) and job satisfaction (r = -0.517) were significantly and moderately negatively correlated with turnover intention (P < .01). The results of the multivariate linear regression analysis revealed that variables including "Whether living with relatives," "Professional identity," "Control and responsibility for work," and "Benefits" jointly accounted for 29.9% of the variance related to turnover intention among novice nurses. "Whether living with relatives," "Professional identity," "Control and responsibility for work," and "Benefits" were highly predictive of turnover intention levels among novice nurses. Hence, potential predictors of turnover intention should be considered, and intervention research should be conducted to reduce the level of turnover intention among novice nurses.

Mechanisms of motor symptom improvement by long-term Tai Chi training in Parkinson’s disease patients

Background

Tai Chi has been shown to improve motor symptoms in Parkinson’s disease (PD), but its long-term effects and the related mechanisms remain to be elucidated. In this study, we investigated the effects of long-term Tai Chi training on motor symptoms in PD and the underlying mechanisms.

Methods

Ninety-five early-stage PD patients were enrolled and randomly divided into Tai Chi (n = 32), brisk walking (n = 31) and no-exercise (n = 32) groups. At baseline, 6 months and 12 months during one-year intervention, all participants underwent motor symptom evaluation by Berg balance scale (BBS), Unified PD rating-scale (UPDRS), Timed Up and Go test (TUG) and 3D gait analysis, functional magnetic resonance imaging (fMRI), plasma cytokine and metabolomics analysis, and blood Huntingtin interaction protein 2 (HIP2) mRNA level analysis. Longitudinal self-changes were calculated using repeated measures ANOVA. GEE (generalized estimating equations) was used to assess factors associated with the longitudinal data of rating scales. Switch rates were used for fMRI analysis. False discovery rate correction was used for multiple correction.

Results

Participants in the Tai Chi group had better performance in BBS, UPDRS, TUG and step width. Besides, Tai Chi was advantageous over brisk walking in improving BBS and step width. The improved BBS was correlated with enhanced visual network function and downregulation of interleukin-1β. The improvements in UPDRS were associated with enhanced default mode network function, decreased L-malic acid and 3-phosphoglyceric acid, and increased adenosine and HIP2 mRNA levels. In addition, arginine biosynthesis, urea cycle, tricarboxylic acid cycle and beta oxidation of very-long-chain fatty acids were also improved by Tai Chi training.

Conclusions

Long-term Tai Chi training improves motor function, especially gait and balance, in PD. The underlying mechanisms may include enhanced brain network function, reduced inflammation, improved amino acid metabolism, energy metabolism and neurotransmitter metabolism, and decreased vulnerability to dopaminergic degeneration.

Trial registration This study has been registered at Chinese Clinical Trial Registry (Registration number: ChiCTR2000036036; Registration date: August 22, 2020).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40035-022-00280-7.

[Methylation detection of phosphatase and tensin homolog deleted on chromosome ten gene promoter in hepatocellular carcinoma samples by next-generation sequencing]

Objective: The purpose of this study is to use the next-generation sequencing (NGS) technology platform to detect the methylation rate of phosphatase and tensin homolog deleted on chromosome ten (PTEN) promoter region in hepatocellular carcinoma (HCC) tissue samples, and to analyze the clinical significance of its correlation with the prognosis of patients receiving sorafenib treatment. Methods: The 52 pairs of tumor tissue and para-cancerous tissue samples from HCC patients treated with sorafenib alone, which were collected and preserved in the Liver Tumor Diagnosis and Research Center of the former 302 Hospital of the People's Liberation Army by the National Natural Science Foundation of China Youth Project with the project batch number 81702986 in 2018, were extracted total DNA from the samples. Then the DNA samples were treated with bisulfite and specific primers were designed to amplify the PTEN promoter region. Finally, the amplified products were analyzed by second-generation sequencing. In the analysis of clinical significance of PTEN methylation, log-rank statistical analysis was used to calculate whether there was a statistical difference in survival between the patient groups. Results: The methylation rate of PTEN promoter region in tumor tissues (29.17%±9.58%) was significantly higher than that in paracancer tissues (4.17%±2.86%)(t=19.970,P<0.05). At the same time, in HCC tissues, the methylation rate of the PTEN promoter region is negatively correlated with its expression (F=47.270,P<0.000 1;Y=-1 800×X+38.03), and the PTEN methylation rate is negatively correlated with the prognosis of patients receiving the molecularly targeted drug Sorafenib (χ²=4.313,P<0.05). Conclusion: This study successfully established a new method for detecting methylation in the promoter region of PTEN, and the methylation rate of PTEN can be used as one of the targets of HCC diagnosis and targeted therapy.

[Application value of urinary IGFBP7 and TIMP-2 in acute kidney injury with decompensated hepatitis B virus-related liver cirrhosis]

Objective: To investigate the application value of new urinary biomarkers insulin-like growth factor binding protein 7 (IGFBP7) and tissue matrix metalloproteinase inhibitor-2 (TIMP-2) in acute kidney injury with decompensated hepatitis B virus-related liver cirrhosis. Methods: 45 newly hospitalized cases with decompensated hepatitis B virus-related liver cirrhosis were selected. Among them, 19 cases were combined with AKI on admission (cirrhosis-AKI group), 26 cases without AKI (cirrhosis-non-AKI group), and 12 healthy cases (normal control group). First-morning urine samples were collected and IGFBP7 and TIMP-2 were detected by enzyme-linked immunosorbent assay (ELISA). Urinary IGFBP7 and serum creatinine (SCr) were dynamically monitored after hospitalization in cirrhosis-non-AKI group. Normally distributed measurement data were compared by t-test, and non-normally distributed measurement data were compared by rank sum test. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to evaluate the diagnostic accuracy of the indicators. Results: Urinary IGFBP7, IGFBP7 with TIMP-2 (IGFBP7×TIMP-2) in cirrhosis-AKI group (n = 19) were equally higher than that of the cirrhosis-non-AKI group (P < 0.05). Urinary IGFBP7, TIMP-2 and IGFBP7×TIMP-2 in cirrhosis-AKI group or cirrhosis-non-AKI group were significantly higher than those of the normal control group (P < 0.01). The AUC of urinary IGFBP7 and urinary IGFBP7×TIMP-2 for diagnosis of AKI were 0.703 (95% CI 0.547-0.860) and 0.700 (95% CI 0.541-0.859), respectively. In the liver cirrhosis-non-AKI group (n = 26), 5 cases of AKI were newly diagnosed according to the changes in SCr during hospitalization (progressive group). Urinary IGFBP7 was significantly increased 2 days before the diagnosis of AKI. The concentration of urinary IGFBP7 at admission in the progressive group (n = 5) was higher than that of the non-progressive group (n = 21) (P < 0.05). Conclusion: Urinary IGFBP7 and TIMP-2 concentrations were significantly increased in patients with decompensated hepatitis B virus-related liver cirrhosis. When AKI occurred, urinary IGFBP7 and IGFBP7×TIMP-2 was further increased. Urinary IGFBP7 is valuable for early AKI diagnosis, and may play a role in predicting AKI occurrence.

Dietary supplementation with arginine and glutamic acid enhances key lipogenic gene expression in growing pigs

Our previous study showed dietary supplementation with Arg and Glu increased intramuscular fat deposition and decreased back fat thickness in pigs, suggesting that the genes involved in lipid metabolism might be regulated differently in muscle and s.c. adipose (SA) tissues. Sixty Duroc × Large White × Landrace pigs with an average initial BW of 77.1 ± 1.3 kg were randomly assigned to 1 of 5 treatment groups (castrated male to female ratio = 1:1). Pigs in the control group were fed a basic diet, and those in experimental groups were fed the basic diet supplemented with 2.05% alanine (isonitrogenous group), 1.00% arginine (Arg group), 1.00% glutamic acid + 1.44% alanine (Glu group), or 1.00% arginine + 1.00% glutamic acid (Arg+Glu group). Fatty acid percentages and mRNA expression levels of the genes involved in lipid metabolism in muscle and SA tissues were examined. The percentages of C14:0 and C16:0 in the SA tissue of Glu group pigs and C14:0 in the longissimus dorsi (LD) muscle of Glu and Arg+Glu groups decreased ( < 0.05) compared to the basic diet group. The Arg+Glu group showed the highest ( < 0.05) hormone-sensitive lipase expression level in SA tissue and higher ( < 0.05) mRNA levels of in the LD muscle than the basic diet and isonitrogenous groups. Additionally, the mRNA level of fatty acid synthase in the Arg+Glu group was more upregulated ( < 0.05) than that of the Arg group. An increase in the mRNA level of in the biceps femoris muscle was also observed in the Arg+Glu group ( < 0.05) compared with the basic diet and isonitrogenous groups. Collectively, these findings suggest that dietary supplementation with Arg and Glu upregulates the expression of genes involved in adipogenesis in muscle tissues and lipolysis in SA tissues.

Dietary supplementation with arginine and glutamic acid modifies growth performance, carcass traits, and meat quality in growing-finishing pigs

Sixty Duroc × Large White × Landrace pigs with an average initial BW of 77.1 ± 1.3 kg were used to investigate the effects of dietary supplementation with arginine and glutamic acid on growth performance, carcass traits, and meat quality in growing-finishing pigs. The animals were randomly assigned to 1 of 5 treatment groups (12 pigs/group, male:female ratio 1:1). The pigs in the control group were fed a basal diet (basal diet group), and those in the experimental groups were fed the basal diet supplemented with 2.05% -alanine (isonitrogenous group), 1.0% -arginine (Arg group), 1% glutamic acid + 1.44% -alanine (Glu group), or 1.0% -arginine + 1.0% glutamic acid (Arg+Glu group). After a 60-d period of supplementation, growth performance, carcass traits, and meat quality were evaluated. The results showed no significant differences ( > 0.05) in growth performance and carcass traits of the pigs in the Arg group relative to the basal diet group; however, the longissimus dorsi (LD) muscle and back fat showed a decrease ( < 0.05) in the percentage of SFA. In the Glu group, the final BW, phase 1 (d 1 to 30) and phase 2 (d 31 to 60) ADFI, and average back fat thickness of the pigs decreased ( < 0.05) by 7.14%, 23.43%, 8.03%, and 33.88%, respectively, when compared with the basal diet group. Dietary Arg+Glu supplementation had no effect ( > 0.05) on the final BW, phase 2 ADFI, and average daily weight gain in pigs but decreased ( < 0.05) their phase 1 ADFI, average back fat thickness, and percentage of SFA in the LD muscle and back fat, and increased ( < 0.05) the i.m. fat (IMF) content of the LD and biceps femoris muscles when compared with the basal diet group. Furthermore, a 16% decrease in yellowness (b* value; < 0.05) was observed in the Arg+Glu group pigs when compared with the isonitrogenous group. These findings suggest that dietary supplementation with both Arg and Glu beneficially increases the IMF deposition and improves the meat color and fatty acid composition without affecting growth performance and s.c. fat in pigs, providing a novel strategy to enhance meat quality in growing-finishing pigs.

FAM196B acts as oncogene and promotes proliferation of gastric cancer cells through AKT signaling pathway

Gastric cancer (GC) is the second leading cause of cancer-related deaths worldwide, but the mechanisms remain unknown. Here we report that family with sequence similarity 196 member B (FAM196B) is highly expressed in primary GC tissues and the expression level is correlated with the clinicopathologic characteristics of GC. In this experiment, knockdown of FAM196B suppressed GC cell proliferation and induced G1/G0 to S phase cell cycle arrest by regulating Cyclin D1, Cyclin A and CDK2 expressions. Furthermore, we investigated the molecular mechanism of FAM196B action in GC. The results showed that knockdown of FAM196B inhibited the activation of AKT signaling pathway. We further revealed that activating of AKT rescued the effect of FAM196B knockdown on cell proliferation and drove cell re-enter into the S phase of the cell cycle with SC79 (a AKT activator). Our findings demonstrated that FAM196B may promote GC cell proliferation by activating AKT signaling pathway. Taken together, this study provides a new evidence that FAM196B functions as a novel oncogene and could be a potential therapeutic target in therapy of GC.

Association between matrix metallopeptidase 1 and type 2 diabetes mellitus coexisting with coronary heart disease in a Han Chinese population

Matrix metallopeptidase 1 (MMP-1) has been reported to be involved in the coexistence of type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). We sought to examine the association between the MMP-1 gene polymorphism and coexistence of T2DM and CHD in a Han Chinese population. We extracted genomic DNA from the peripheral blood of 794 subjects, including 378 patients with coexisting T2DM and CHD and 416 healthy controls. We selected several single nucleotide polymorphisms of the MMP-1 gene and genotyped them using the MassARRAY system, before analyzing the data with Haploview 4.0 and SPSS 20.0. A statistical difference was found in the distribution of rs1799750 genotypes between the patient and control groups (P = 0.041). The frequency of the 2G/2G genotype was 44.25 and 37.0% among patients and control subjects, respectively. Moreover, the frequency of the 2G allele was 65.9% among patients and 59.6% in the control group, and this difference was found to be significant (P = 0.010). Elevated body mass index was also associated with the 2G/2G genotype. Thus, MMP-1 rs1799750 may be involved in the development of coexisting T2DM and CHD in the Han Chinese population.

Gene expression and enzyme activity of lipoprotein lipase correlate with intramuscular fat content in Guangxi san-huang and Arbor Acres chickens

Lipoprotein lipase (LPL) is a key enzyme in lipid metabolism. This study investigated LPL gene expression, LPL enzyme activity, and the correlation of each with intramuscular fat (IMF) in Chinese Guangxi san-huang (GXSH) and Arbor Acres (AA) chickens. The results showed that age and breed had significant effects on LPL expression and enzyme activity. Correlation analyses showed significant positive correlations between LPL expression levels and IMF contents in the breast and thigh tissues of both GXSH (r = 0.712, P = 0.001; r = 0.792, P < 0.001, respectively) and AA (r = 0.644, P < 0.001; r = 0.545, P < 0.001, respectively) chickens. The results also indicated a significant positive correlation between LPL enzyme activity and IMF contents in the breast and thigh tissues of both GXSH (r = 0.615, P = 0.001; r = 0.685, P < 0.001, respectively) and AA (r = 0.600, P = 0.001; r = 0.528, P = 0.003, respectively) chickens. The results indicated that the LPL gene was significantly correlated with IMF in these two breeds. The results presented here could contribute to knowledge of LPL mRNA developmental expression patterns and enzyme activity, and it could facilitate further research on the molecular mechanisms underlying IMF deposition in chickens.

Promoter mutation and reduced expression of BRCA1 in canine mammary tumors

Breast cancer 1, early onset (BRCA1) is one of the most important genes in human familial breast cancer, which also plays an important role in canine mammary tumors. The objectives of this study were to determine the promoter sequence of canine BRCA1, to investigate its promoter mutation status and to describe BRCA1 expression pattern in canine mammary tumors. The promoter sequence of canine BRCA1 was acquired by aligning human BRCA1 promoter sequence with canine genomic sequence and confirmed by standard promoter activity analysis. Same as human BRCA1 promoter, the CAAT box and G/C box were found in canine BRCA1 promoter. In order to explore the mutation status of the promoter region and to investigate the expression pattern of this gene, 10 normal canine mammary tissues, 15 benign mammary tumors and 15 malignant mammary tumors were used. By sequencing, 46.7% of the malignant mammary tumors were found with a deletion of one cytosine in the promoter region. The mRNA expression of BRCA1 was significantly reduced in benign and malignant mammary tumors (P<0.05), and the protein expression of BRCA1 was significantly reduced in malignant mammary tumors (P<0.05). This study is the first time to determine the canine BRCA1 promoter sequence and to describe the promoter mutation status in canine mammary tumors.

Complete mitochondrial genome of the Cyclemys dentata and phylogenetic analysis of the major family Geoemydidae

In the present study, the complete mitochondrial (mt) genome of Cyclemys dentata was determined using PCR reactions. The structural organization and gene order of C. dentata were equivalent to those of most other vertebrates. The mt genome was 16,489 bp in length, has rich A+T content, consisting of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region (D-loop). All protein-coding genes started with ATG, many genes have complete stop codons, except ND2, COX3, ND3, and cyt-b genes had incomplete stop codons of T. The light-strand replication origin (OL) of C. dentata might fold into a stable stem-loop secondary structure, and its loop had 2 nt less than that of the Cyclemys atripons OL sequence. The D-Loop of C. dentata contained a central domain (CD), 2 extended termination associated sequences (ETAS1, ETAS2) and 3 conserved sequence blocks (CSB1, CSB2, CSB3). The average length of 20 turtles' mt genomes was 16,692.5 bp, including 34.1% A, 27.0% T, 26.0% C and 12.9% G. The C. dentata mitochondrial genome could provide useful data for further studies on phylogenetics and conservation genetics of this species. The phylogenetic relationships of the family Geoemydidae were analyzed by maximum-likelihood (ML) and neighbor-joining (NJ) based on concatenated sequences of 13 protein-coding genes from 20 turtle species. The ML and NJ trees had homologous topologies. The results support the existing classification of the genera of Geoemydidae, that C. dentata was a sister species of C. atripons, Pyxidea nested in Cuora, and Chinemys was synonymous with Mauremys.

Effects of dietary lysine levels on apparent nutrient digestibility and serum amino Acid absorption mode in growing pigs

Two experiments were conducted to determine the effects of different dietary lysine levels on the apparent nutrient digestibility, the serum amino acid (AA) concentration, and the biochemical parameters of the precaval and portal vein blood in growing pigs. In Experiment 1, 15 noncannulated pigs received diets with different lysine densities (0.65%, 0.95%, and 1.25% lysine) for 13 d. A total collection digestion test was performed, and blood samples were collected from the precaval vein at the end of the experiment. In Experiment 2, four cannulated pigs were fed the same diets of Experiment 1. The experiment used a self-control experimental design and was divided into three periods. On d 5 of each period, at 0.5 h before feeding and hourly up to 8 h after feeding, single blood samples were collected from catheters placed in the portal vein. In Experiment 1, some serum AAs (including lysine), serum urinary nitrogen (SUN), and total protein (TP) concentrations were significantly affected by the dietary lysine levels (p<0.05). Moreover, the 0.65% lysine treatment showed a significant lower apparent digestibility of gross energy, dry matter, crude protein, and phosphorus than the other treatments (p<0.05). In Experiment 2, serum lysine, histidine, phenylalanine, threonine, valine, isoleucine (p = 0.0588), triglyceride, and SUN (p = 0.0572) concentrations were significantly affected by the dietary lysine levels (p<0.05). Additionally, almost all of the determined serum AA and total AA concentrations reached their lowest values at 0.5 h before feeding and their highest values at 2 h after feeding (p<0.05). These findings indicate that the greatest absorption of AA occurred at 2 h after feeding and that the dynamic profile of serum AA is affected by the dietary lysine levels. Moreover, when the dietary lysine content was 0.95%, the growing pigs achieved a better nutrient digestibility and serum metabolites levels.

Effects of dietary thiazolidinedione supplementation on growth performance, intramuscular fat and related genes mRNA abundance in the longissimus dorsi muscle of finishing pigs

The objective of this study was to investigate the effect of dietary supplementation with thiazolidinedione (TZD) on growth performance and meat quality of finishing pigs. In Experiment 1, 80 castrated finishing pigs (Large White×Landrace, BW = 54.34 kg) were randomly assigned to 2 treatments with 5 replicates of 8 pigs each. The experimental pigs in the 2 groups were respectively fed with a diet with or without a TZD supplementation (15 mg/kg). In Experiment 2, 80 castrated finishing pigs (Large White×Landrace, BW = 71.46 kg) were divided into 2 treatments as designed in Experiment 1, moreover, carcass evaluations were performed. The results from Experiment 1 showed that TZD supplementation could significantly decreased the average daily feed intake (ADFI) (p<0.05) during 0 to 28 d, without impairing the average daily gain (ADG) (p>0.05). In Experiment 2, the ADG was significantly increased by TZD supplementation during 14 to 28 d and 0 to 28 d (p<0.05) and the feed:gain ratio (F:G) was significantly decreased by TZD supplementation during 0 to 28 d (p<0.05). Compared with the control group, TZD group had significantly higher serum triglyceride (TG) concentration at 28h and serum high-density lipoprotein (HDL) levels at 14 d (p<0.05). Moreover, there was an apparent improvement in the marbling score (p<0.10) and intramuscular fat (IMF) content (p<0.10) of the longissimus dorsi muscle in pigs treated by TZD supplementation. Real-time RT-PCR analyses demonstrated that pigs of TZD group had higher mRNA abundance of PPARγ coactivator 1 (PGC-1) (p<0.05) and fatty acid-binding protein 3 (FABP3) (p<0.05) than pigs of control group. Taken together, these results suggested that dietary TZD supplementation could improve growth performance and increase the IMF content of finishing pigs through regulating the serum parameters and genes mRNA abundance involved in fat metabolism.

Decorin-induced proliferation of avian myoblasts involves the myostatin/Smad signaling pathway

Decorin, a small leucine-rich proteoglycan as a component of the extracellular matrix, plays an important role in the skeletal muscle development. It has been reported that decorin promoted proliferation and differentiation of muscle cells by restraining myostatin activity in rodents. However, the effects and mechanisms of decorin on avian myoblast proliferation are not understood clearly. Thus, in our research, decorin overexpressing and knocking-down quail myoblast-7 (QM7) myoblasts were established to explore the effects of decorin on avian myoblast proliferation by flow cytometry. The results showed that overexpression of decorin enhanced the proliferation of QM7 myoblasts, which was accompanied by the upregulation of follistatin and primary muscle regulatory factors (i.e., myogenic factor 5, myogenic factor 1, myogenin), and downregulation of myostatin expression, as well as the decreased phosphorylation level of SMAD family member 3 (Smad3). In line with expectations, decorin RNAi displayed an opposite effect on the proliferation and gene expression pattern of QM7 cells. In conclusion, our in vitro studies suggested the decorin-mediated myostatin/Smad signaling pathway might be involved in the regulation of avian myoblast proliferation.

Cationic microRNA-delivering nanovectors with bifunctional peptides for efficient treatment of PANC-1 xenograft model

Therapeutic strategies based on modulation of microRNA activity possess much promise in cancer therapy, but the in vivo delivery of microRNA to target sites and its penetration into tumor tissues remain great challenge. In this work, miR-34a-delivering therapeutic nanocomplexes with a tumor-targeting and -penetrating bifunctional CC9 peptide were proposed for efficient treatment of pancreatic cancers. In vitro study indicated that the nanoparticle-based miR-34a delivery systems could effectively facilitate cellular uptake and greatly up-regulate the mRNA level of miR-34a in PANC-1 cell lines. The up-regulation of miR-34a remarkably induced cell cycle arrest and apoptosis, suppressed the tumor cell migration and inhibited the target gene expressions such as E2F3, Bcl-2, c-myc and cyclin D1. More importantly, the in vivo systemic administration of the developed targeting miR-34a delivery systems in a pancreatic cancer model significantly inhibited tumor growth and induced cancer cell apoptosis. Such bifunctional peptide-conjugated miRNA-delivering nanocomplexes should have great potential applications in cancer therapy.

Active immunization of fatty acid translocase specifically decreased visceral fat deposition in male broilers

Lipid accumulation of avian adipocytes is mainly dependent upon the fatty acid transmembrane uptake process mediated by membrane proteins, such as fatty acid translocase (FAT/CD36), fatty acid transport protein 1, and caveolin-2. To examine the effects of FAT/CD36 on spatial-specific fat deposition, 60 broiler chickens were randomly allocated to 2 groups by sex. Each male or female group contained 2 subgroups (n = 14-15) inoculated by intramuscular injection with chicken FAT/CD36 or BSA (control) immunogens at 34, 49, and 63 d. The subcutaneous and visceral fat deposits were measured, as were levels of plasma triglyceride and free fatty acid. Serum antibody titer was measured by ELISA. The mRNA expression levels of fatty acid transport-related genes in the adipose tissue of the male broilers were investigated to reveal the relationships among various fatty acid transporters. The results showed that active immunization with FAT/CD36 could significantly decrease the visceral fat of the male broilers by up to 40%, but it had no effect on subcutaneous fat stores of male broilers or on either site of fat deposition in female broilers. The concentration of plasma free fatty acids increased in the experimental groups for both male and female broilers. After the FAT/CD36 immunization, very low density lipoprotein receptor mRNA expression was upregulated in both the subcutaneous and visceral fat of male broilers, whereas peroxisome proliferator-activated receptor γ, FAT/CD36, and acyl-CoA binding protein mRNA expression levels were upregulated only in the visceral fat of male broilers. These results indicated a novel role of chicken FAT/CD36 in fat deposition, with sex- and spatial-specific effects.

Isolation of plasma membranes from Drosophila embryos

Cell surface components probably play an important role in early embryonic development. However, hardly any information is available on the structure or regulation of expression of the corresponding genes. As a first step in approaching this issue, we devised a procedure to obtain enriched plasma membranes from embryonic Drosophila cells. Membranes are fractionated according to two independent physical parameters: size, using velocity gradient centrifugation and density, using isopicnic gradient centrifugation. The final membrane fraction is enriched by 6 to 8 fold with respect to the plasma membrane enzyme marker Na+/K+ ATPase and substantially depleted of the mitochondrial enzyme marker cytochrome C oxidase. Two-dimensional polyacrylamide gel electrophoresis of the purified membranes reveals enrichment for specific proteins and electron microscopy reveals membrane vesicles in abundance. The enriched fraction should be suitable for the preparation of antibody probes that recognize cell surface components.

Effect of nifA product on suppression of Nif- phenotype of gln mutation and constitutive synthesis of nitrogenase in Klebsiella pneumoniae

This paper describes the role of nifA product on the ammonia regulation of nitrogen fixation in K. pneumoniae. A plasmid carrying nifA gene under the promoter of tetracycline resistance gene was constructed. When this nifA carrying plasmid was introduced into a glnAG mutant, the Nif- phenotype of this gln mutant was suppressed. Furthermore, when the plasmid was introduced into the wild type and glnAG mutant, derepression of nitrogenase synthesis in ammonia occurred in both strains and the products of nif genes can be detected by two-dimensional gel electrophoresis in the extracts of these ammonia-grown bacterial cells. The constitutive synthesis of nitrogenase in NH4+ was also demonstrated in free living nitrogen-fixing bacteria, Enterobacter cloacae, when the bacteria received the plasmid carrying nifA gene from K. pneumoniae.