De Novo Synthesis of Dihydro-β-ionone through Metabolic Engineering and Bacterium-Yeast Coculture

Dihydro-β-ionone is a common type of ionone used in the flavor and fragrance industries because of its characteristic scent. The production of flavors in microbial cell factories offers a sustainable and environmentally friendly approach to accessing them, independent of extraction from natural sources. However, the native pathway of dihydro-β-ionone remains unclear, hindering heterologous biosynthesis in microbial hosts. Herein, we devised a microbial platform for de novo syntheses of dihydro-β-ionone from a simple carbon source with glycerol. The complete dihydro-β-ionone pathway was reconstructed in Escherichia coli with multiple metabolic engineering strategies to generate a strain capable of producing 8 mg/L of dihydro-β-ionone, although this was accompanied by a surplus precursor β-ionone in culture. To overcome this issue, Saccharomyces cerevisiae was identified as having a conversion rate for transforming β-ionone to dihydro-β-ionone that was higher than that of E. coli via whole-cell catalysis. Consequently, the titer of dihydro-β-ionone was increased using the E. coli-S. cerevisiae coculture to 27 mg/L. Our study offers an efficient platform for biobased dihydro-β-ionone production and extends coculture engineering to overproducing target molecules in extended metabolic pathways.

Impact of propofol and sevoflurane anesthesia on cognition and emotion in gastric cancer patients undergoing radical resection

BACKGROUND

Propofol and sevoflurane are commonly used anesthetic agents for maintenance anesthesia during radical resection of gastric cancer. However, there is a debate concerning their differential effects on cognitive function, anxiety, and depression in patients undergoing this procedure.

AIM

To compare the effects of propofol and sevoflurane anesthesia on postoperative cognitive function, anxiety, depression, and organ function in patients undergoing radical resection of gastric cancer.

METHODS

A total of 80 patients were involved in this research. The subjects were divided into two groups: Propofol group and sevoflurane group. The evaluation scale for cognitive function was the Loewenstein occupational therapy cognitive assessment (LOTCA), and anxiety and depression were assessed with the aid of the self-rating anxiety scale (SAS) and self-rating depression scale (SDS). Hemodynamic indicators, oxidative stress levels, and pulmonary function were also measured.

RESULTS

The LOTCA score at 1 d after surgery was significantly lower in the propofol group than in the sevoflurane group. Additionally, the SAS and SDS scores of the sevoflurane group were significantly lower than those of the propofol group. The sevoflurane group showed greater stability in heart rate as well as the mean arterial pressure compared to the propofol group. Moreover, the sevoflurane group displayed better pulmonary function and less lung injury than the propofol group.

CONCLUSION

Both propofol and sevoflurane could be utilized as maintenance anesthesia during radical resection of gastric cancer. Propofol anesthesia has a minimal effect on patients' pulmonary function, consequently enhancing their postoperative recovery. Sevoflurane anesthesia causes less impairment on patients' cognitive function and mitigates negative emotions, leading to an improved postoperative mental state. Therefore, the selection of anesthetic agents should be based on the individual patient's specific circumstances.

Integrative analysis of transcriptome and proteome in primary Sjögren syndrome

OBJECTIVE

Primary Sjögren's syndrome (pSS) is a intricate autoimmune disease mainly characterized of immune-mediated destruction of exocrine tissues, such as salivary and lacrimal glands, occurring dry mouth and eyes. Although some breakthroughs in understanding pSS have been uncovered, many questions remain about its pathogenesis, especially the internal relations between exocrine glands and secretions.

METHOD

Transcriptomic and proteomic analyses were conducted on salivary tissues and saliva in experimental Sjögren syndrome (ESS). The ESS model was established by immunization with salivary gland protein. The expression of mRNAs and proteins in salivary tissues and saliva were determined by high-throughput sequencing transcriptomic analysis and LC-MS/MS-based proteome, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were used to recognize dysregulated genes and proteins. The association between RNA and protein abundance was investigated to provides a comprehensive understanding of RNA-protein correlations in the pathogenesis of pSS.

RESULTS

As a result, we successfully established the ESS model. We recognized 3221 differentially expressed genes (DEGs) and 253 differentially expressed proteins (DEPs). The sample analysis showed that 61 proteins overlapped through the integrative analysis of transcriptomics and proteomics data. The enrichment pathway analysis of DEGs and DEPs in samples showed alterations in renin-angiotensin-system (RAS), lysosome, and apoptosis. Notably, we found that some genes, such as AGT, FN1, Klk1b26, Klk1, Klk1b5, Klk1b3 had a consistent trend in the regulation at the RNA and protein levels and might be potential diagnostic biomarkers of pSS.

CONCLUSION

Herein, we found critical processes and potential biomakers that may contribute to pSS pathogenesis by analyzing dysregulated genes and pathways. Additionally, the integrative multi-omics datasets provided additional insight into understanding complicated disease mechanisms.

The expression level of fibroblast growth factor gene in serum samples of lung cancer patients

Lung cancer, one of the most deadly and dangerous types of cancer in the world, kills many men and women every year. Activation of fibroblast growth factor signals plays a role in the pathogenesis of several cancers, including lung cancer. Also, this factor may indicate prognosis and is related to the survival rate in patients with NSCLC. Therefore, this research investigated the level of fibroblast growth factor gene expression in the serum of people with lung cancer. In this research, 60 serum samples of healthy people and 60 serum samples of people with NSCLC were prepared, and personal and clinicopathological information of the studied people were collected by questionnaires. Then, plasma isolation, RNA extraction, cDNA synthesis, primers design, implementation, and changes in fibroblast growth factor gene expression in the serum of healthy and lung cancer patients were evaluated by the Real-time PCR method. REST software was used to analyze the results. The findings showed no significant difference in the expression of the fibroblast growth factor gene in the serum of people with the first to third stages of metastasis. However, in the serum of patients with the fourth stage of metastasis, the expression level of this gene was significantly decreased by 3.92 times compared to normal samples (P<0.05). According to the results of this study, it is possible to use the expression level of the fibroblast growth factor gene in people's serum to predict the metastasis stage of lung cancer.

Bilobalide Induces Apoptosis in 3T3-L1 Mature Adipocytes through ROS-Mediated Mitochondria Pathway

Bilobalide exhibits numerous beneficial bioactivities, including neuroprotective, anti-inflammatory, and antioxidant activity. Our previous study demonstrated that bilobalide inhibits adipogenesis and promotes lipolysis. The dose-dependent cytotoxicity was found to be specific to the mature adipocytes only, indicating the potential for regulating apoptosis in them. Herein, we aimed to investigate the apoptotic effects of bilobalide on 3T3-L1 mature adipocytes and elucidate the underlying mechanisms thereof. Flow cytometry analysis (FACS) revealed the pro-apoptotic effects of bilobalide on these cells. Bilobalide induced early apoptosis by reducing the mitochondrial membrane potential (MMP). DNA fragmentation was confirmed using TUNEL staining. Additionally, bilobalide increased the intracellular reactive oxygen species (ROS) levels and activities of Caspases 3/9. Pre-treatment with NAC (an ROS scavenger) confirmed the role of ROS in inducing apoptosis. Moreover, bilobalide up- and down-regulated the expression of Bax and Bcl-2, respectively, at the mRNA and protein expression levels; upregulated the Bax/Bcl-2 ratio; triggered the release of cytochrome c from the mitochondria; and increased the protein expression of cleaved Caspase 3, cleaved Caspase 9, and PARP cleavage. These results support the conclusion that bilobalide induces apoptosis in mature 3T3-L1 adipocytes through the ROS-mediated mitochondrial pathway, and offers potential novel treatment for obesity.

Efficient production of the glycosylated derivatives of baicalein in engineered Escherichia coli

Baicalein-7-O-glucoside and baicalein-7-O-rhamnoside have been proven to possess many pharmacological activities and are potential candidate drug leads and herb supplements. However, their further development is largely limited due to low content in host plants. Few studies reported that both bioactive plant components are prepared through the bioconversion of baicalein that is considered as the common biosynthetic precursor of both compounds. Herein, we constructed a series of the engineered whole-cell bioconversion systems in which the deletion of competitive genes and the introduction of exogenous UDP-glucose supply pathway, glucosyltransferase, rhamnosyltransferase, and the UDP-rhamnose synthesis pathway are made. Using these engineered strains, the precursor baicalein is able to be transformed into baicalein-7-O-glucoside and baicalein-7-O-rhamnoside, with high-titer production, respectively. The further optimization of fermentation conditions led to the final production of 568.8 mg/L and 877.0 mg/L for baicalein-7-O-glucoside and baicalein-7-O-rhamnoside, respectively. To the best of our knowledge, it is the highest production in preparation of baicalein-7-O-glucoside from baicalein so far, while the preparation of baicalein-7-O-rhamnoside is the first reported via bioconversion approach. Our study provides a reference for the industrial production of high-value products baicalein-7-O-glucoside and baicalein-7-O-rhamnoside using engineered E. coli. KEY POINTS: • Integrated design for improving the intracellular UDP-glucose pool • High production of rare baicalein glycosides in the engineered E. coli • Baicalein-7-O-glucoside and baicalein-7-O-rhamnoside.

Concentrated extract of Prunus mume fruit exerts dual effects in 3T3-L1 adipocytes by inhibiting adipogenesis and inducing beiging/browning

Background

The fruit Prunus mume has beneficial effects in the treatment of obesity and metabolic syndrome. However, its mechanism of action is unclear.

Objective

We assessed the effect of a concentrated water extract of P. mume fruit (CEPM) on adipogenesis and beiging/browning in 3T3-L1 cells.

Methods

The cell viability was determined by MTT assay. Lipid accumulation was assessed with Oil Red O (ORO) staining under different concentrations of CEPM. The effects of CEPM treatment during differentiation on beiging/browning and mitochondrial biogenesis in 3T3-L1 cells were investigated.

Results

CEPM treatment suppressed differentiation and decreased lipid accumulation by downregulating the expression of key adipogenic genes, including PPARγ, C/EBPα, SREBP-1c, FAS, and perilipin A. In contrast, CEPM treatment increased the mitochondrial DNA (mtDNA) content and mRNA levels of mitochondrial biogenesis genes, including NAMPT, Nrf1, Nrf2, and CPT1α, and reduced reactive oxygen species levels. Importantly, CEPM increased the expression of brown/beige hallmark genes (Pgc-1α, Ucp1, Cidea, Cox7α1, Cox8b, Cd137, and Pdk-4), as well as proteins (UCP1, PGC-1α, NRF1, TBX1, and CPT1α). The high-performance liquid chromatography (HPLC) analysis reveals that CEPM contains mumefural, naringin, 5-HMF, citric acid, caffeic acid, and hesperidin.

Conclusion

The first evidence we provided showed that CEPM has a dual role in 3T3-L1 cells inhibiting adipogenesis and promoting beiging/browning, and hence, could be a potential agent in the fight against obesity.

Cloning and Characterization of a Novel Carotenoid Cleavage Dioxygenase 1 from Helianthus annuus

Natural β-ionone, a high-value flavoring agent, has been widely applied in the food, cosmetics, and perfume industry. However, attempts to overproduce β-ionone in microorganisms have been limited by the efficiency of carotenoid cleavage dioxygenases (CCDs), which catalyzes β-carotene in the biosynthesis pathway. In order to obtain CCD genes responsible for the specific cleavage of carotenoids generating β-ionone, a novel carotenoid cleavage dioxygenase 1 from Helianthus annuus was cloned and overexpressed in Escherichia coli BL21(DE3). The recombinant CCD was able to cleave a variety of carotenoids at the 9, 10 (9', 10') sites to produce C13 products in vitro, including β-ionone, pseudoionone, 3-hydroxy-4-oxo-β-ionone, 3-hydroxy-β-ionone, and 3-hydroxy-α-ionone, which vary depending on the carotenoid substrates. In comparison with lycopene and zeaxanthin, HaCCD1 also showed the high specificity for β-carotene to cleave the 9, 10 (9', 10') double bond to produce β-ionone in E. coli accumulating carotenoids. Finally, the expression of HaCCD1 in E. coli was optimized, and biochemical characterizations were further clarified. The optimal activity of HaCCD1 was at pH 8.8 and 50 °C. The V_max for β-apo-8'-carotenal was 10.14 U/mg, while the K_m was 0.32 mM. Collectively, our study provides a valuable enzyme for the synthesis of natural β-ionone by biotransformation and synthetic biology platform.

Proteomic profiling of saliva reveals association of complement system with primary Sjögren's syndrome

INTRODUCTION

To compare the saliva proteomes of experimental Sjögren's syndrome (ESS) model mice and healthy controls to identify potential diagnostic biomarkers for primary Sjögren's syndrome (pSS).

METHODS

Proteins were extracted from the saliva of three ESS and three normal control mice using the data-independent acquisition technique. R language was used to identify the differentially expressed proteins (DEPs). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to functionally annotate the DEPs. The protein-protein interaction (PPI) network was constructed and the core proteins were identified with the STRING website and Cytoscape software. The concentrations of Serpin family G member 1 (SERPING1), C3, complement factor H (CFH), fibrinogen alpha (FGA), and fibrinogen gamma (FGG) in saliva were determined by ELISA.

RESULTS

A total of 1722 DEPs were identified in the saliva of the ESS mice relative to the controls, of which 50 showed significantly different expression levels between the two groups. SERPING1, C3, CFH, FGA, and FGG were significantly downregulated, and keratin 4 (Krt4) and transglutaminase 3 (TGM3) were upregulated in the saliva of ESS mice. The PPI network showed that SERPING1, C3, FGG, FGA, TGM3, and hemopexin (HPX) were the core proteins. ELISA results showed that the expression of C3, CFH, FGA, and SERPING1 were significantly downregulated in the saliva of ESS mice. However, the expression of FGG was a little downregulated but with no significant difference. SERPING1, FGG, and FGA may downregulate the complement C3 by inhibiting immune complement system, thereby promoting pSS progression.

CONCLUSIONS

The salivary proteome of ESS mice was markedly different from that of healthy controls, suggesting that salivary proteomics is a promising noninvasive diagnostic tool for pSS. SERPING1, C3, CFH, FGA, and FGG are potential biomarkers of pSS.

The predictive values of GGT and Hcy in the risk stratifications and prognoses of NSTE-ACS patients

OBJECTIVE

This research was designed to probe into the predictive value of glutamyltransferase (GGT) and homocysteine (Hcy) in the risk stratifications and prognoses of non-ST segment elevation acute coronary syndrome (NSTE-ACS) patients.

METHODS

A total of 182 NSTE-ACS patients treated with percutaneous coronary intervention (PCI) in our hospital from February 2016 to May 2018 were recruited as a patient group (PG). They were followed up for one year, and the occurrences of any major adverse cardiovascular events (MACCE) were recorded. In addition, 90 healthy volunteers were recruited as a normal group (NG) during the same period. The GGT and Hcy expressions in the serum of both groups were tested, and the predictive values of these levels, the patient risk stratification, and the prognoses were analyzed.

RESULTS

Compared with the NG, the GGT and Hcy expressions in the PG were markedly higher (P < 0.05). Compared with the patients without MACE, the GGT and Hcy expressions in the serum of those with MACE increased dramatically (P < 0.05). The serum GGT and Hcy levels were positively correlated with the NSTE-ACS patients' SYNTAX scores (P < 0.05). A Kaplan-Meier curve indicated that the MACE-free survival rate of the patients with low GGT levels was dramatically higher than the survival rate of the patients with high GGT levels, and the MACE-free survival rate of low Hcy patients was significantly higher than the MACE-free survival rate of the high Hcy patients (P < 0.05). Our COX proportional hazards regression models indicated that the serum GGT and Hcy levels are independent predictors of MACCE in NSTE-ACS patients (P < 0.05). Our ROC curve analysis indicated that the serum GGT and Hcy levels are diagnostic criteria for predicting whether MACE occurred in NSTE-ACS patients.

CONCLUSION

The serum GGT and Hcy levels are positively correlated with the severity of coronary artery disease (CAD) in NSTE-ACS patients. They are independent predictors of adverse prognoses and can help refine the risk stratification management in clinical work.

Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes), Polysaccharides Suppressed Adipogenesis and Stimulated Lipolysis in HPA-v and 3T3-L1 Adipocytes

Ganoderma lucidum polysaccharides (GLP) are one of the major bioactive components with many beneficial properties. In the present study we aimed to systematically evaluate the effects of GLP on lipid metabolism in human (HPA-v) and murine adipocytes (3T3-L1). Cell viability was assessed by MTT assay. Lipid accumulation in mature adipocytes were evaluated by ORO staining and quantified using the triglyceride (TG) assay. Lipolysis was investigated by measuring the free glycerol released in the cell culture medium after treatments. The mRNA and protein levels of key genes regulating lipid metabolism were determined by qRT-PCR and western blotting in HPA-v cells. ORO staining showed that GLP suppressed lipid accumulation similarly in both HPA-v and 3T3-L1 cells. TG assay confirmed that GLP significantly inhibited cell differentiation (p < 0.001). The lipolysis assay showed that GLP enhanced triglyceride hydrolysis in both adipocytes (p < 0.05). GLP stimulated AMPK phosphorylation, which promoted the phosphorylation of ACC1, its downstream target. qRT-PCR and western blotting showed that the genes encoding transcription factors for adipocyte differentiation (PPARγ, C/EBPα, and SREBPlc) and certain adipogenic genes (ACC1, PLIN1, and FASN) were downregulated (p < 0.05). The lipolytic gene HSL was upregulated and highly phosphorylated (activated) at mRNA and protein levels, respectively, upon GLP treatment. These results suggested that GLP possessed beneficial antiadipogenic effects and can potentially be developed into antiobesity products.

Identification of an autophagy-related gene signature that can improve prognosis of hepatocellular carcinoma patients

Background

Autophagy is a programmed cell degradation mechanism that has been associated with several physiological and pathophysiological processes, including malignancy. Improper induction of autophagy has been proposed to play a pivotal role in the progression of hepatocellular carcinoma (HCC).

Methods

Univariate Cox regression analysis of overall survival (OS) was performed to identify risk-associated autophagy-related genes (ARGs) in HCC data set from The Cancer Genome Atlas (TCGA). Multivariate cox regression was then performed to develop a risk prediction model for the prognosis of 370 HCC patients. The multi-target receiver operating characteristic (ROC) curve was used to determine the model’s accuracy. Besides, the relationship between drug sensitivity and ARGs expression was also examined.

Results

A total of 62 differentially expressed ARGs were identified in HCC patients. Univariate and multivariate regression identified five risk-associated ARGs (HDAC1, RHEB, ATIC, SPNS1 and SQSTM1) that were correlated with OS in HCC patients. Of importance, the risk-associated ARGs were independent risk factors in the multivariate risk model including clinical parameters such as malignant stage (HR = 1.433, 95% CI = 1.293–1.589, P < 0.001). In addition, the area under curve for the prognostic risk model was 0.747, which indicates the high accuracy of the model in prediction of HCC outcomes. Interestingly, the risk-associated ARGs were also correlated with drug sensitivity in HCC cell lines.

Conclusion

We developed a novel prognostic risk model by integrating the molecular signature and clinical parameters of HCC, which can effectively predict the outcomes of HCC patients.

Mussel-inspired nanofibrous sheet for suture-less stomach incision surgery

We report a dopamine-based crosslinker-conjugated gelatin/polycaprolactone nanofibrous sheet. The nanosheet was then employed to treat stomach incisions without sutures during surgery.

Increased production of mitochondrial reactive oxygen species and reduced adult life span in an insecticide-resistant strain of Anopheles gambiae

Control of the malaria vector An. gambiae is still largely obtained through chemical intervention using pyrethroids, such as permethrin. However, strains of An. gambiae that are resistant to the toxic effects of pyrethroids have become widespread in several endemic areas over the last decade. The objective of this study was to assess differences in five life-history traits (larval developmental time and the body weight, fecundity, hatch rate, and longevity of adult females) and energy metabolism between a strain of An. gambiae that is resistant to permethrin (RSP), due to knockdown resistance and enhanced metabolic detoxification, and a permethrin susceptible strain reared under laboratory conditions. We also quantified the expression levels of five antioxidant enzyme genes: GSTe3, CAT, GPXH1, SOD1, and SOD2. We found that the RSP strain had a longer developmental time than the susceptible strain. Additionally, RSP adult females had higher wet body weight and increased water and glycogen levels. Compared to permethrin susceptible females, RSP females displayed reduced metabolic rate and mitochondrial coupling efficiency and higher mitochondrial ROS production. Furthermore, despite higher levels of GSTe3 and CAT transcripts, RSP females had a shorter adult life span than susceptible females. Collectively, these results suggest that permethrin resistance alleles might affect energy metabolism, oxidative stress, and adult survival of An. gambiae. However, because the strains used in this study differ in their genetic backgrounds, the results need to be interpreted with caution and replicated in other strains to have significant implications for malaria transmission and vector control.

N-glycosylation of ICAM-2 is required for ICAM-2-mediated complete suppression of metastatic potential of SK-N-AS neuroblastoma cells

Background

Cell adhesion molecules (CAMs) are expressed ubiquitously. Each of the four families of CAMs is comprised of glycosylated, membrane-bound proteins that participate in multiple cellular processes including cell-cell communication, cell motility, inside-out and outside-in signaling, tumorigenesis, angiogenesis and metastasis. Intercellular adhesion molecule-2 (ICAM-2), a member of the immunoglobulin superfamily of CAMs, has six N-linked glycosylation sites at amino acids (asparagines) 47, 82, 105, 153, 178 and 187. Recently, we demonstrated a previously unknown function for ICAM-2 in tumor cells. We showed that ICAM-2 suppressed neuroblastoma cell motility and growth in soft agar, and induced a juxtamembrane distribution of F-actin in vitro. We also showed that ICAM-2 completely suppressed development of disseminated tumors in vivo in a murine model of metastatic NB. These effects of ICAM-2 on NB cell phenotype in vitro and in vivo depended on the interaction of ICAM-2 with the cytoskeletal linker protein α-actinin. Interestingly, ICAM-2 did not suppress subcutaneous growth of tumors in mice, suggesting that ICAM-2 affects the metastatic but not the tumorigenic potential of NB cells. The goal of the study presented here was to determine if the glycosylation status of ICAM-2 influenced its function in neuroblastoma cells.

Methods

Because it is well documented that glycosylation facilitates essential steps in tumor progression and metastasis, we investigated whether the glycosylation status of ICAM-2 affected the phenotype of NB cells. We used site-directed mutagenesis to express hypo- or non-glycosylated variants of ICAM-2, by substituting alanine for asparagine at glycosylation sites, and compared the impact of each variant on NB cell motility, anchorage-independent growth, interaction with intracellular proteins, effect on F-actin distribution and metastatic potential in vivo.

Results

The in vitro and in vivo phenotypes of cells expressing glycosylation site variants differed from cells expressing fully-glycosylated ICAM-2 or no ICAM-2. Most striking was the finding that mice injected intravenously with NB cells expressing glycosylation site variants survived longer (P ≤ 0.002) than mice receiving SK-N-AS cells with undetectable ICAM-2. However, unlike fully-glycosylated ICAM-2, glycosylation site variants did not completely suppress disseminated tumor development.

Conclusions

Reduced glycosylation of ICAM-2 significantly attenuated, but did not abolish, its ability to suppress metastatic properties of NB cells.

Physician-patient-companion communication and decision-making: a systematic review of triadic medical consultations

OBJECTIVE

To systematically review quantitative and qualitative studies exploring physician-adult patient-adult companion (triadic) communication and/or decision-making within all medical encounters.

METHODS

Studies were identified via database searches and reference lists. One author assessed eligibility of studies, verified by two co-authors. Data were extracted by one author and cross-checked for accuracy. Two authors assessed the quality of included articles using standardized criteria.

RESULTS

Of the 8409 titles identified, 52 studies were included. Summary statements and tables were developed for each of five identified themes. Results indicated companions regularly attended consultations, were frequently perceived as helpful, and assumed a variety of roles. However, their involvement often raised challenges. Patients with increased need were more often accompanied. Some companion behaviours were felt to be more helpful (e.g. informational support) and less helpful (e.g. dominating/demanding behaviours), and preferences for involvement varied widely.

CONCLUSION

Triadic communication in medical encounters can be helpful but challenging. Based on analysis of included studies, preliminary strategies for health professionals are proposed.

PRACTICE IMPLICATIONS

Preliminary strategies for health professionals include (i) encourage/involve companions, (ii) highlight helpful companion behaviours, (iii) clarify and agree upon role preferences of patient/companions. Future studies should develop and evaluate specific strategies for optimizing triadic consultations.

Nuclear genomic control of naturally occurring variation in mitochondrial function in Drosophila melanogaster

Background

Mitochondria are organelles found in nearly all eukaryotic cells that play a crucial role in cellular survival and function. Mitochondrial function is under the control of nuclear and mitochondrial genomes. While the latter has been the focus of most genetic research, we remain largely ignorant about the nuclear-encoded genomic control of inter-individual variability in mitochondrial function. Here, we used Drosophila melanogaster as our model organism to address this question.

Results

We quantified mitochondrial state 3 and state 4 respiration rates and P:O ratio in mitochondria isolated from the thoraces of 40 sequenced inbred lines of the Drosophila Genetic Reference Panel. We found significant within-population genetic variability for all mitochondrial traits. Hence, we performed genome-wide association mapping and identified 141 single nucleotide polymorphisms (SNPs) associated with differences in mitochondrial respiration and efficiency (P ≤1 × 10^-5). Gene-centered regression models showed that 2–3 SNPs can explain 31, 13, and 18% of the phenotypic variation in state 3, state 4, and P:O ratio, respectively. Most of the genes tagged by the SNPs are involved in organ development, second messenger-mediated signaling pathways, and cytoskeleton remodeling. One of these genes, sallimus (sls), encodes a component of the muscle sarcomere. We confirmed the direct effect of sls on mitochondrial respiration using two viable mutants and their coisogenic wild-type strain. Furthermore, correlation network analysis revealed that sls functions as a transcriptional hub in a co-regulated module associated with mitochondrial respiration and is connected to CG7834, which is predicted to encode a protein with mitochondrial electron transfer flavoprotein activity. This latter finding was also verified in the sls mutants.

Conclusions

Our results provide novel insights into the genetic factors regulating natural variation in mitochondrial function in D. melanogaster. The integrative genomic approach used in our study allowed us to identify sls as a novel hub gene responsible for the regulation of mitochondrial respiration in muscle sarcomere and to provide evidence that sls might act via the electron transfer flavoprotein/ubiquinone oxidoreductase complex.

Recovery of nickel ions from simulated electroplating rinse water by electrodeionization process

Pure water production and recovery of Ni(2+) from dilute NiSO(4) solution via improved electrodeionization (EDI) process were investigated. It was indicated that, with the feed water containing 50 mg L(-1) Ni(2+), the dilute resistivity of the EDI could achieve 3 MOmega cm which gave a Ni(2+) rejection more than 99.8% while the Ni(2+) was concentrated as high as 1,583 mg L(-1) in the concentrate stream. The current efficiency was as high as 40% and the concentrate factor could reach 31.7. The experiment results demonstrated that, just in a single process, it was feasible to purifying and concentrating dilute nickel wastewater synchronously by the EDI technology.

Cystin localizes to primary cilia via membrane microdomains and a targeting motif

Primary cilia are dynamic, complex structures that contain >500 proteins, including several related to polycystic kidney disease. How these proteins target to cilia and assemble is unknown. We previously identified Cys1 as the gene responsible for disease in Cys1(cpk) mice, a mouse model of autosomal recessive polycystic kidney disease; this gene encodes cystin, a 145-amino acid cilium-associated protein. Here, we characterized the localization of cystin in the embryonic kidney and liver, in isolated renal collecting ducts, and in an inner medullary collecting duct mouse cell line. Because endogenous levels of cystin expression are low, we generated inner medullary collecting duct cell lines that stably express enhanced green fluorescence protein-tagged constructs of wild-type cystin or various truncation mutants. We determined that cystin is myristoylated at its G2 residue and that N-myristoylated cystin fractionates with membrane microdomains. Furthermore, the N-myristoylation signal is necessary but not sufficient to target cystin to the primary cilium. Analysis of deletion and chimeric constructs identified an AxEGG motif that is necessary to target and retain cystin in the cilium. Derangement of these localization motifs may lead to cystic kidney disease.

Two gene determinants are differentially involved in the biogenesis of Fap1 precursors in Streptococcus parasanguis

Mature Fap1, a 200-kDa fimbria-associated adhesin, is required for fimbrial biogenesis and biofilm formation in Streptococcus parasanguis. Fap1-like proteins are found in the genomes of many streptococcal and staphylococcal species. Fap1 is a serine-rich glycoprotein modified by O-linked glycan moieties. In this study, we identified a seven-gene cluster including secY2, orf1, orf2, orf3, secA2, gtf1, and gtf2 that is localized immediately downstream of fap1. The lower G+C contents and the presence of a putative transposase element suggest that this gene cluster was horizontally transferred from other bacteria and represents a genomic island. At least two genes in this island mediated Fap1 biogenesis. Mutation of a glucosyltransferase (Gtf1) gene led to accumulation of a Fap1 precursor, which had no detectable glycan moieties. Inactivation of a gene coding for an accessory Sec protein (SecY2) resulted in expression of a distinct Fap1 precursor, which reacted with one glycan-specific Fap1 antibody but not with another glycan-specific antibody. Furthermore, partially glycosylated Fap1 was detected on the cell surface and in the culture supernatant. These data suggest that SecY2 has a role in complete glycosylation of Fap1 and imply that SecY2 is not the only translocation channel for the Fap1 precursor and that alternative secretion machinery exists. Together, Gtf1 and SecY2 are involved in biogenesis of two distinct Fap1 precursors in S. parasanguis. Discovery of the effect of an accessory Sec protein on Fap1 glycosylation suggests that Fap1 secretion and glycosylation are coupled during Fap1 biogenesis.

GroEL-GroES solubilizes abundantly expressed xylulokinase in Escherichia coli

AIMS

The aims of the present work were to solubilize the abundantly expressed recombinant xylulokinase in Escherichia coli and to develop a reliable xylulokinase assay.

METHODS AND RESULTS

Three mutants of xylulokinase of Bacillus megaterium that were expressed at high level but formed insoluble protein in E. coli BL21(DE3)pLysS were selected for solubility study. The solubility of xylulokinase increased eight to 77-fold after introduction of molecular chaperones GroEL-GroES into the host.

CONCLUSION

This investigation reports that GroEL-GroES minimizes the formation of insoluble protein in three highly expressed recombinant xylulokinases and an improved xylulokinase assay.

SIGNIFICANCE AND IMPACT OF THE STUDY

Commercial production of bioethanol is critically dependent on the development of an efficient and low-cost process of enzymatic conversion of xylan, a major component in lignocellulose biomass, to xylulose-5-phosphate, which can then be channelled into pentose phosphate pathway and metabolized to ethanol. The improved intracellular xylulokinase activity is expected to facilitate the xylose degradation.

Control of hyperchaos

A general method for controlling chaotic systems with one or more positive Lyapunov exponents is investigated analytically and numerically. The method retains the formal features of the adaptive adjustment mechanism and can be equally applied to various types of the unstable fixed points. It is shown that the method proposed here neither asks for any prior analytical knowledge of the system, nor any internal or external controlling parameters in advance.

Stabilizing unstable discrete systems

A general method for stabilizing unstable discrete systems to a fixed point or high-period orbit is developed analytically and numerically in this paper. It is shown that the method can be equally applied to the systems with one or more positive Lyapunov exponents. Moreover, the method does not require a prior analytical knowledge of the system under investigation, nor any additional control parameters.

Smad7 mediates apoptosis induced by transforming growth factor beta in prostatic carcinoma cells

Transforming growth factor beta (TGF-beta) is an important regulator of apoptosis in some cell types, but the underlying molecular mechanisms are largely unknown. TGF-beta signals through type I and type II receptors and downstream effector proteins, termed Smads. TGF-beta induces the phosphorylation of Smad2 and Smad3 (receptor-activated Smads) which associate with Smad4 and translocate to the nucleus, where they regulate gene transcription [1]. Smad7 protein is induced by TGF-beta1 and has been classified as an inhibitory Smad. Smad7 prevents phosphorylation of receptor-activated Smads, thereby inhibiting TGF-beta-induced signaling responses [1]. Smad7 expression is increased in rat prostatic epithelial cells undergoing apoptosis as a result of castration [2]. Here we have shown that TGF-beta1 treatment or ectopic expression of Smad7 in human prostatic carcinoma cells (PC-3U) induces apoptosis. Furthermore, TGF-beta1-induced apoptosis was prevented by inhibition of Smad7 expression, by antisense mRNA in stably transfected cell lines or upon transient transfection with antisense oligonucleotides in several investigated cell lines. These findings provide evidence for a new effector function for Smad7 in TGF-beta1 signaling.

Effects of enzyme inducers and inhibitor on the pharmacokinetics of intravenous 2-(allylthio)pyrazine, a new chemoprotective agent, in rats

In order to find what types of hepatic cytochrome P450 (CYP) isozymes are involved in the metabolism of 2-(allylthio)pyrazine (2-AP) in rats, enzyme inducers, such as phenobarbital, 3-methylcholanthrene, dexamethasone, or isoniazid, and an enzyme inhibitor, such as SKF 525-A were pretreated. After 1-min intravenous administration of 2-AP, 50 mg/kg, to rats pretreated with SKF 525-A (a non-specific CYP inhibitor in rats), the plasma concentrations were significantly higher, and the area under plasma concentration-time curve from time zero to time infinity (AUC) was significantly greater (1365 compared with 1034 microg min/mL) as a result of significantly slower total body clearance (Cl) (36.6 compared with 48.3 mL/min/kg) than those in control rats, indicating that 2-AP was metabolized by CYP isozymes. After 1-min intravenous administration of 2-AP, 50 mg/kg, to rats pretreated with dexamethasone (an inducer of CYP3A in rats), phenobarbital (an inducer of CYP2B1/2, 2C6, 2C7, and 3A1/2 in rats), and 3-methylcholanthrene (an inducer of CYP1A1/2 and 2A1 in rats), the plasma concentrations were significantly lower, and AUC was significantly smaller (27, 41 and 60% decrease, respectively, compared with respective control rats) owing to faster Cl [37 (p>0.05), 70 (p<0.001), and 150% (p<0.001) increase, respectively, compared with respective control rats].

[Effect of Saikosaponin-d on up-regulating GR mRNA expression and inhibiting cell growth in human leukemia cells]

OBJECTIVE

To study the effect of Saikosaponin-d (SSd) on the expression of glucocorticoid receptor (GR) mRNA and cell growth in HL60 cells.

METHODS

Antiproliferation effects of SSd on HL60 cells were determined by 3H-thymidine incorporation. Cell cycle analysis was also performed by flow cytometry. GRmRNA was analyzed by northern blot analysis.

RESULTS

After 48 hours treatment with 10 micrograms/ml SSd, 3H-thymidine incorporation decreased in HL60 cells and the effect was time and dose dependent. The flow cytometry analysis showed HL60 cells were arrested at G0/G1 phase. The expression of GR mRNA increased.

CONCLUSION

SSd exhibits the inhibition effects on cell growth in HL60 cells and could up-regulate the expression of GR mRNA in HL60 cells.

[The influence of nerve growth factor on inferior alveolar nerves regeneration in the silicone tubes]

OBJECTIVE

To explore the effect of exogenous nerve growth factor(NGF) in the regeneration of adult white rabbits inferior alveolar nerve within the silicone tubes.

METHODS

In 24 adults white rabbits. A bilateral 8 mm inferior alveolar nerve gaps were created, and the proximal and distal stumps were inserted into a 12 mm silicone tube. The silicone tube of the right side was filled with exogenous NGF(experimental group) and the contralateral side was filled with saline (control group). Regeneration of the nerves was assessed by histological exam and nerve electrophysiological appreciation. Total number of the regenerating myelinated nerve fibers, the conduction velocities of nerves the thickness of myelin sheaths and the cross section area of myelinated nerve fibers between the experimental and the control groups were compared.

RESULTS

The results showed that: 1. The experimental groups demonstrated more myelinated nerve fibers than that of the controls in 12 and 18 weeks. 2. At the same time following surgery, the myelin sheath thickness and the cross section area of myelinated nerves in the experimental groups were significantly greater than that in the controls. 3. In 12 and 18 weeks, the conduction velocities of regenerating nerves in the experimental groups were faster than that of the controls.

CONCLUSION

This study suggested that exogenous NGF can enhance regeneration of inferior alveolar nerve with necovery of its sensory function.

[Saikosaponin-d up-regulates GR mRNA expression and induces apoptosis in HL-60 cells]

OBJECTIVE

To research the effect of saikosaponin-d (SSd) on the expression of glucocorticoid receptor (GR) mRNA and induction of apoptosis in HL-60 cells.

METHODS

Antiproliferation effects of SSd on HL-60 cells were determined by 3H-thymidine incorporation. Apoptosis of the SSd-treated cells was determined by DNA fragmentation analysis and flow cytometry. GR mRNA was analyzed by Northern blot analysis.

RESULTS

After 48 h treatment with 10 micrograms/ml SSd, 3H-thymidine incorporation was decreased in HL-60 cells and the effects were time and dose dependent. DNA ladder appeared after 60 h treatment with SSd. The flow cytometry analysis showed HL-60 cells was arrested at G0/G1 phase and apoptotic peak appeared in sub-G1 phase. The expression of GR mRNA was increased.

CONCLUSION

SSd up-regulates the expression of GR mRNA, inhibits the cell growth and induces apoptosis in HL-60 cells.

[Surgical reconstruction of laryngeal and tracheal stenosis]

OBJECTIVE

Reconstruction of laryngotracheal stenosis.

METHOD

According to the pathologic condition of the larynx and trachea, various surgical procedures were designed for the treatment of laryngotracheal stenosis. These techniques included endoscopic management, laser therapy and laryngotrachoetomy with autogenous tissue and stent.

RESULT

Among 36 patients, 32 were decannulated. The success rate was 88.8%.

CONCLUSION

In order to improve the curation effects of laryngjotrachal stenosis, the choice of surgical procedure must be individualized to the pathologic condition of larynx and trachea, as well as the experience of the surgeon. Learning previous successful experience is also very important for a good result.

[Effect of Gengnianjian on up regulated estrogen receptor mRNA to substance P and beta-endorphin in hypothalamus of aging female rats]

OBJECTIVE

To investigate the effect of Chinese herbal formula Gengnianjian on estrogen receptor (ER), ERmRNA substance P (SP) and beta-endorphin (beta-EP) in the hypothalamus of aging female rats.

METHODS

ER proteins were determined by radioligand binding assay, ER mRNA was analyzed by Northern blot analysis and the levels of beta-EP and SP were detected by immunohistochemistry.

RESULTS

In aging rats, lowered ER and ER mRNA in the hypothalamus were still up-regulated by low serum E2 level, but not in rats of after the age of 21 months; Gengnianjian significantly increased ER protein level and ER mRNA expression, decreased SP and increased the level of beta-EP in the hypothalamus in aging female rats before 21 months of age, without changing of serum E2 level. In EB group, serum E2 and beta-EP levels increased and SP level decreased but ER expression suppressed in the hypothalamus except after 21 months.

CONCLUSION

Enhance estrogen bioactivity can decrease the level of SP and increase the level of beta-EP in hypothalamus of aging female rats. Herbal formula Gengnianjian increase-EP level and decrease SP level by raising the level of ER and ER mRNA.

[Clinical experience of coronal flap approach in surgery of anterior skull base tumor]

Surgery of the anterior skull base tumor has been undertaken in 7 cases by coronal flap approach, of which 4 cases were malignant tumors and 3 cases were benign tumors. The dura became torn in 3 cases and resected in 2 cases due to tumor invasion. The dura and bony defects could be repaired with galea, pericranial flaps and fascia flaps of temporalis. The bigger bony defect was consolidated with scalp flap. Three out of 4 cases with malignant tumors were free of tumors for 6 years, 4 years and 17 months, respectively: 1 case died of tumor recurrence after 18 months. No case had postoperative complications.