Nematodirus spp. are among the most common nematodes of ruminants worldwide. N. oiratianus and N. spathiger are distributed worldwide as highly prevalent gastrointestinal nematodes, which cause emerging health problems and economic losses. Accurate identification of Nematodirus species is essential to develop effective control strategies for Nematodirus infection in ruminants. Mitochondrial DNA (mtDNA) could provide powerful genetic markers for identifying these closely related species and resolving phylogenetic relationships at different taxonomic levels.
In the present study, the complete mitochondrial (mt) genomes of N. oiratianus and N. spathiger from small ruminants in China were obtained using Long-range PCR and sequencing.
The complete mt genomes of N. oiratianus and N. spathiger were 13,765 bp and 13,519 bp in length, respectively. Both mt genomes were circular and consisted of 36 genes, including 12 genes encoding proteins, 2 genes encoding rRNA, and 22 genes encoding tRNA. Phylogenetic analyses based on the concatenated amino acid sequence data of all 12 protein-coding genes by Bayesian inference (BI), Maximum likelihood (ML) and Maximum parsimony (MP) showed that the two Nematodirus species (Molineidae) were closely related to Dictyocaulidae.
The availability of the complete mtDNA sequences of N. oiratianus and N. spathiger not only provides new mtDNA sources for a better understanding of nematode mt genomics and phylogeny, but also provides novel and useful genetic markers for studying diagnosis, population genetics and molecular epidemiology of Nematodirus spp. in small ruminants.
Nematodirus oiratianus; Nematodirus spathiger; Mitochondrial genome; Phylogenetic analyses
Dispersed particle gel (DPG) particles of nano- to micron- to mm-size have been prepared successfully and will be used for profile control treatment in mature oilfields. The profile control and enhanced oil recovery mechanisms of DPG particles have been investigated using core flow tests and visual simulation experiments. Core flow test results show that DPG particles can easily be injected into deep formations and can effectively plug the high permeability zones. The high profile improvement rate improves reservoir heterogeneity and diverts fluid into the low permeability zone. Both water and oil permeability were reduced when DPG particles were injected, but the disproportionate permeability reduction effect was significant. Water permeability decreases more than the oil permeability to ensure that oil flows in its own pathways and can easily be driven out. Visual simulation experiments demonstrate that DPG particles can pass directly or by deformation through porous media and enter deep formations. By retention, adsorption, trapping and bridging, DPG particles can effectively reduce the permeability of porous media in high permeability zones and divert fluid into a low permeability zone, thus improving formation profiles and enhancing oil recovery.
Cryptosporidium is an enteric apicomplexan parasite, which can infect yaks, leading to reduction of milk production and poor weight gain. White yak (Bos grunniens) is a unique yak breed inhabiting only in Tianzhu Tibetan Autonomous County, Gansu province, northwestern China. The objective of the present study was to molecularly determine Cryptosporidium infection and species in white yaks.
Seventy-six fecal samples from white yaks in Tianzhu Tibetan Autonomous County, Gansu province were collected. The small subunit ribosomal RNA (SSU rRNA) gene of each sample was amplified using nested PCR and sequenced. The Cryptosporidium species was determined by comparison of the obtained sequences with that of corresponding Cryptosporidium sequences available in GenBank by BLAST (http://www.ncbi.nlm.nih.gov/BLAST/) and phylogenetic analysis with maximum likelihood (ML) using PAUP*. The overall prevalence of Cryptosporidium infection in white yak was 5.26% (4/76). Species identification showed C. andersoni in one sample (collected in September), and C. bovis in three samples (one collected in November and two collected in September).
The present investigation revealed the existence of Cryptosporidium infection in white yaks in China, for the first time, and two Cryptosporidium species, namely C. andersoni and C. bovis, were identified. These findings extend the host range for Cryptosporidium spp., and also provide base-line information for further studies of molecular epidemiology and control of Cryptosporidium infection in the unique white yaks.
Cryptosporidium spp; Genetic characterization; Prevalence; White Yak; China
Poly(3-hydroxypropionate) (P3HP) is a biodegradable and biocompatible thermoplastic. In our previous study, a pathway for P3HP production was constructed in recombinant Esecherichia coli. Seven exogenous genes in P3HP synthesis pathway were carried by two plasmid vectors. However, the P3HP production was severely suppressed by strain instability due to plasmid loss. In this paper, two strategies, chromosomal gene integration and plasmid addiction system (PAS) based on amino acid anabolism, were applied to construct a genetically stable strain. Finally, a combination of those two methods resulted in the best results. The resultant strain carried a portion of P3HP synthesis genes on chromosome and the others on plasmid, and also brought a tyrosine-auxotrophy based PAS. In aerobic fed-batch fermentation, this strain produced 25.7 g/L P3HP from glycerol, about 2.5-time higher than the previous strain with two plasmids. To the best of our knowledge, this is the highest P3HP production from inexpensive carbon sources.
Cryptosporidium baileyi is the dominant Cryptosporidium species in birds causing emerging health problems in the poultry industry, and is also a model to study the biology of Cryptosporidium spp.. IL-17 (also called IL-17A) is a hallmark pro-inflammatory cytokine of Th17 cells that plays an important role in several human autoimmune diseases and microbial infection disease of many animals, and it may play a role in Cryptosporidium infection.
The present study examined the mRNA level of IL-17 and Th17 response relative cytokines in the trachea and spleen of C. baileyi-infected chickens at different time points using real-time quantitative PCR (qPCR).
All examined cytokines in the trachea were up-regulated in the infected chickens compared with the uninfected control during C. baileyi infection. Significant increased IL-17 mRNA level in the trachea was observed as early as 12 h post infection (pi), peaking at 24 h pi and 10 d pi, and declining thereafter. The transcription levels of IL-17 and Th17 response relative cytokines in spleen were also significantly increased at different time points during the infection.
IL-17 was indicated to participate in the induction of inflammation during infection of some intracellular protozoan parasites. The results in the present study suggest that IL-17 may play a role in immunity against Cryptosporidium infection, and provide basic information for determining the role of Th17 cell in Cryptosporidium infection.
Cryptosporidium baileyi; IL-17; Chicken; Immunity
The present study was conducted to clarify whether treatment with L-serine can improve the brain repair and neurorestoration of rats after permanent middle cerebral artery occlusion (pMCAO). After pMCAO, the neurological functions, brain lesion volume, and cortical injury were determined. GDNF, NGF, NCAM L1, tenascin-C, and Nogo-A levels were measured. Proliferation and differentiation of the neural stem cells (NSCs) and proliferation of the microvessels in the ischemic boundary zone of the cortex were evaluated. Treatment with L-serine (168 mg/kg body weight, i.p.) began 3 h after pMCAO and was repeated every 12 h for 7 days or until the end of the experiment. L-Serine treatment: 1) reduced the lesion volume and neuronal loss; 2) improved the recovery of neurological functions; 3) elevated the expression of nerve growth-related factors; and 4) facilitated the proliferation of endogenous NSCs and microvessels activated after pMCAO and increased the number of new-born neurons. 5) D-cycloserine, an inhibitor of serine hydroxymethyltransferase, blunted the effects of L-serine on NSC proliferation, differentiation, microvascular proliferation. In conclusions, L-serine treatment in pMCAO rats can reduce brain injury and facilitate neurorestoration which is partly associated with the improvement of proliferation of NSCs and microvessels, reconstruction of neurovascular units and resultant neurorepair. The effects of L-serine on endogenous NSC proliferation and microvascular proliferation are partly mediated by the action of L-serine as a substrate for the production of one-carbon groups used for purine and pyrimidine synthesis and modulation of the expression of some nerve growth-related factors.
Necrotizing fasciitis is a rare but fatal infection, characterized by the rapid progression of necrosis of the fascia, skin, soft tissue and muscle. The most common bacteria associated with necrotizing fasciitis is group A streptococcus, although other pathogens have also been implicated. In the present study, a case of community-acquired necrotizing fasciitis, complicated with septic shock and multiple organ dysfunction syndromes due to Pseudomonas aeruginosa, is presented. Despite intensive medical treatment, the condition of the patient deteriorated rapidly and the patient subsequently succumbed to multiple organ failure. In view of the rapid progression and high mortality rate of this disease, early surgery, as well as novel therapeutic approaches for septic shock are required to improve the outcome for patients.
necrotizing fasciitis; pseudomonas aeruginosa; septic shock
Macaques are the most widely distributed nonhuman primates and used as animal models in biomedical research. The availability of full-genome sequences from them would be essential to both biomedical and primate evolutionary studies. Previous studies have reported whole-genome sequences from rhesus macaque (Macaca mulatta) and cynomolgus macaque (M. fascicularis, CE), both of which belong to the fascicularis group. Here, we present a 37-fold coverage genome sequence of the Tibetan macaque (M. thibetana; TM). TM is an endemic species to China belonging to the sinica group. On the basis of mapping to the rhesus macaque genome, we identified approximately 11.9 million single-nucleotide variants), of which 3.9 million were TM specific, as assessed by comparison two Chinese rhesus macaques (CR) and two CE genomes. Some genes carried TM-specific homozygous nonsynonymous variants (TSHNVs), which were scored as deleterious in human by both PolyPhen-2 and SIFT (Sorting Tolerant From Intolerant) and were enriched in the eye disease genes. In total, 273 immune response and disease-related genes carried at least one TSHNV. The heterozygosity rates of two CRs (0.002617 and 0.002612) and two CEs (0.003004 and 0.003179) were approximately three times higher than that of TM (0.000898). Polymerase chain reaction resequencing of 18 TM individuals showed that 29 TSHNVs exhibited high allele frequencies, thus confirming their low heterozygosity. Genome-wide genetic divergence analysis demonstrated that TM was more closely related to CR than to CE. We further detected unusual low divergence regions between TM and CR. In addition, after applying statistical criteria to detect putative introgression regions (PIRs) in the TM genome, up to 239,620 kb PIRs (8.84% of the genome) were identified. Given that TM and CR have overlapping geographical distributions, had the same refuge during the Middle Pleistocene, and show similar mating behaviors, it is highly likely that there was an ancient introgression event between them. Moreover, demographic inferences revealed that TM exhibited a similar demographic history as other macaques until 0.5 Ma, but then it maintained a lower effective population size until present time. Our study has provided new insight into the macaque evolutionary history, confirming hybridization events between macaque species groups based on genome-wide data.
Tibetan macaque; whole-genome sequencing; SNVs; genetic divergence; introgression; demographic trajectories
Gastrointestinal nematodes of livestock have major socio-economic importance worldwide. In small ruminants, Chabertia spp. are responsible for economic losses to the livestock industries globally. Although much attention has given us insights into epidemiology, diagnosis, treatment and control of this parasite, over the years, only one species (C. ovina) has been accepted to infect small ruminants, and it is not clear whether C. erschowi is valid as a separate species.
The first and second internal transcribed spacers (ITS-1 and ITS-2) regions of nuclear ribosomal DNA (rDNA) and the complete mitochondrial (mt) genomes of C. ovina and C. erschowi were amplified and then sequenced. Phylogenetic re-construction of 15 Strongylida species (including C. erschowi) was carried out using Bayesian inference (BI) based on concatenated amino acid sequence datasets.
The ITS rDNA sequences of C. ovina China isolates and C. erschowi samples were 852–854 bp and 862 -866 bp in length, respectively. The mt genome sequence of C. erschowi was 13,705 bp in length, which is 12 bp shorter than that of C. ovina China isolate. The sequence difference between the entire mt genome of C. ovina China isolate and that of C. erschowi was 15.33%. In addition, sequence comparison of the most conserved mt small subunit ribosomal (rrnS) and the least conserved nad2 genes among multiple individual nematodes revealed substantial nucleotide differences between these two species but limited sequence variation within each species.
The mtDNA and rDNA datasets provide robust genetic evidence that C. erschowi is a valid strongylid nematode species. The mtDNA and rDNA datasets presented in the present study provide useful novel markers for further studies of the taxonomy and systematics of the Chabertia species from different hosts and geographical regions.
Chabertia spp; Nuclear ribosomal DNA; Internal transcribed spacer (ITS); Mitochondrial DNA; Phylogenetic analysis
A dispersed particle gel (DPG) was successfully prepared from a polymer gel at room temperature. The polymer gel system, morphology, viscosity changes, size distribution, and zeta potential of DPG particles were investigated. The results showed that zirconium gel systems with different strengths can be cross-linked within 2.5 h at low temperature. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM) results showed that the particles were polygonal particles with nano-size distribution. According to the viscosity changes, the whole preparation process can be divided into two major stages: the bulk gel cross-linking reaction period and the DPG particle preparation period. A polymer gel with a 3-dimensional network was formed in the bulk gel cross-linking reaction period whereas shearing force and frictional force were the main driving forces for the preparation of DPG particles, and thus affected the morphology of DPG particles. High shearing force and frictional force reduced the particle size distribution, and then decreased the zeta potential (absolute value). The whole preparation process could be completed within 3 h at room temperature. It could be an efficient and energy-saving technology for preparation of DPG particles.
To develop an orthotopic, allogeneic, uterine transplantation technique and an effective immunosuppressive protocol in the sheep model.
In this pilot study, 10 sexually mature ewes were subjected to laparotomy and total abdominal hysterectomy with oophorectomy to procure uterus allografts. The cold ischemic time was 60 min. End-to-end vascular anastomosis was performed using continuous, non-interlocking sutures. Complete tissue reperfusion was achieved in all animals within 30 s after the vascular re-anastomosis, without any evidence of arterial or venous thrombosis. The immunosuppressive protocol consisted of tacrolimus, mycophenolate mofetil and methylprednisolone tablets. Graft viability was assessed by transrectal ultrasonography and second-look laparotomy at 2 and 4 weeks, respectively.
Viable uterine tissue and vascular patency were observed on transrectal ultrasonography and second-look laparotomy. Histological analysis of the graft tissue (performed in one ewe) revealed normal tissue architecture with a very subtle inflammatory reaction but no edema or stasis.
We have developed a modified procedure that allowed us to successfully perform orthotopic, allogeneic, uterine transplantation in sheep, whose uterine and vascular anatomy (apart from the bicornuate uterus) is similar to the human anatomy, making the ovine model excellent for human uterine transplant research.
The relationship between admission time and intensive care unit (ICU) mortality is inconclusive and influenced by various factors. This study aims to estimate the effect of admission time on ICU outcomes in a tertiary teaching hospital in China by propensity score matching (PSM) and stratified analysis.
A total of 2,891 consecutive patients were enrolled in this study from 1 January 2009 to 29 December 2011. Multivariate logistic regression and survival analysis were performed in this retrospective study. PSM and stratified analysis were applied for confounding factors, such as Acute Physiology and Chronic Health Evaluation II (APACHE II) score and admission types.
Compared with office hour subgroup (n = 2,716), nighttime (NT, n = 175) subgroup had higher APACHE II scores (14 vs. 8, P < 0.001), prolonged length of stay in the ICU (42 vs. 24 h, P = 0.011), and higher percentages of medical (8.6% vs. 3.3%, P < 0.001) and emergency (59.4% vs. 12.2%, P < 0.001) patients. Moreover, NT admissions were related to higher ICU mortality [odds ratio (OR), 1.725 (95% CI 1.118–2.744), P = 0.01] and elevated mortality risk at 28 days [14.3% vs. 3.2%; OR, 1.920 (95% CI 1.171–3.150), P = 0.01]. PSM showed that admission time remained related to ICU outcome (P = 0.045) and mortality risk at 28 days [OR, 2.187 (95% CI 1.119–4.271), P = 0.022]. However, no mortality difference was found between weekend and workday admissions (P = 0.849), even if weekend admissions were more related to higher APACHE II scores compared with workday admissions.
NT admission was associated with poor ICU outcomes. This finding may be related to shortage of onsite intensivists and qualified residents during NT. The current staffing model and training system should be improved in the future.
The formation of fusion protein in biosynthetic pathways usually improves metabolic efficiency either channeling intermediates and/or colocalizing enzymes. In the metabolic engineering of biochemical pathways, generating unnatural protein fusions between sequential biosynthetic enzymes is a useful method to increase system efficiency and product yield. Here, we reported a special case. The malonyl-CoA reductase (MCR) of Chloroflexus aurantiacus catalyzes the conversion of malonyl-CoA to 3-hydroxypropionate (3HP), and is a key enzyme in microbial production of 3HP, an important platform chemical. Functional domain analysis revealed that the N-terminal region of MCR (MCR-N; amino acids 1-549) and the C-terminal region of MCR (MCR-C; amino acids 550-1219) were functionally distinct. The malonyl-CoA was reduced into free intermediate malonate semialdehyde with NADPH by MCR-C fragment, and further reduced to 3HP by MCR-N fragment. In this process, the initial reduction of malonyl-CoA was rate limiting. Site-directed mutagenesis demonstrated that the TGXXXG(A)X(1-2)G and YXXXK motifs were important for enzyme activities of both MCR-N and MCR-C fragments. Moreover, the enzyme activity increased when MCR was separated into two individual fragments. Kinetic analysis showed that MCR-C fragment had higher affinity for malonyl-CoA and 4-time higher Kcat/Km value than MCR. Dissecting MCR into MCR-N and MCR-C fragments also had a positive effect on the 3HP production in a recombinant Escherichia coli strain. Our study showed the feasibility of protein dissection as a new strategy in biosynthetic systems.
Baylisascaris schroederi is one of the most significant threats to the giant panda’s survival, responsible for half of the deaths reported from 2001 to 2005. MicroRNA (miRNA) has been identified as one of the key factors for gene regulations at the post-transcriptional level, and also considered as a potential control and treatment target against infectious diseases.
The present study investigated the miRNA profile of B. schroederi via high throughput sequencing and real-time quantitative PCR.
A total of 18.07 million raw reads were obtained and 18.01 million were identified with high quality. By analysis of standard stem-loop structures, 108 miRNA candidates were predicted, including 60 known miRNAs and 48 novel ones. Target prediction revealed that the “chitinase” was the most abundant target with 483 sequences, and 263 targets were related to ovarian and egg development. The ribosomal protein related sequences occupied 449 sequences.
Previous studies have shown that some parasites secrete chitinases for exsheathment and/or for penetrating the peritrophic matrix of the host. It therefore seems that B. schroederi may be effectively regulated by miRNAs for development, invasion, and reproduction. Given that chitinases have been identified as important biological control agents for pests, identification of microRNAs in B. schroederi of the giant panda would provide useful information for the development of biological control strategies and/or vaccines against B. schroederi infection in the giant panda.
Baylisascaris schroederi; Giant panda; microRNA (miRNA); miRNA target
Tick is one of important ectoparasites capable of causing direct damage to their hosts and also acts as vectors of relevant infectious agents. In the present study, the taxa of 10 ticks, collected from Qinling giant pandas (Ailuropoda melanoleuca qinlingensis) in Qinling Mountains of China in April 2010, were determined using morphology and molecular markers (nucleotide ITS2 rDNA and mitochondrial 16S). Microscopic observation demonstrated that the morphological features of these ticks were similar to Haemaphysalis flava. Compared with other Haemaphysalis species, genetic variations between Haemaphysalis collected from A. m. qinlingensis and H. flava were the lowest in ITS2 rDNA and mitochondrial 16S, with sequence differences of 2.06%–2.40% and 1.30%–4.70%, respectively. Phylogenetic relationships showed that all the Haemaphysalis collected from A. m. qinlingensis were grouped with H. flava, further confirmed that the Haemaphysalis sp. is H. flava. This is the first report of ticks in giant panda by combining with morphology and molecular markers. This study also provided evidence that combining morphology and molecular tools provide a valuable and efficient tool for tick identification.
To investigate the mechanisms underlying the neuroprotective effect of L-serine, permanent focal cerebral ischemia was induced by occlusion of the middle cerebral artery while monitoring cerebral blood flow (CBF). Rats were divided into control and L-serine-treated groups after middle cerebral artery occlusion. The neurological deficit score and brain infarct volume were assessed. Nissl staining was used to quantify the cortical injury. L-serine and D-serine levels in the ischemic cortex were analyzed with high performance liquid chromatography. We found that L-serine treatment: 1) reduced the neurological deficit score, infarct volume and cortical neuron loss in a dose-dependent manner; 2) improved CBF in the cortex, and this effect was inhibited in the presence of apamin plus charybdotoxin while the alleviation of both neurological deficit score and infarct volume was blocked; and 3) increased the amount of L-serine and D-serine in the cortex, and inhibition of the conversion of L-serine into D-serine by aminooxyacetic acid did not affect the reduction of neurological deficit score and infarct volume by L-serine. In conclusion, improvement in regional CBF by L-serine may contribute to its neuroprotective effect on the ischemic brain, potentially through vasodilation which is mediated by the small- and intermediate-conductance Ca2+-activated K+ channels on the cerebral blood vessel endothelium.
A simple two-step method was employed for preparing nano-sized gold nanoparticles-graphene composite to construct a GNPs-GR-SDS modified electrode. Hemoglobin (Hb) was successfully immobilized on the surface of a basal plane graphite (BPG) electrode through a simple dropping technique. Direct electrochemistry and electrocatalysis of the hemoglobin-modified electrode was investigated. The as-prepared composites showed an obvious promotion of the direct electro-transfer between hemoglobin and the electrode. A couple of well-defined and quasi-reversible Hb CV peaks can be observed in a phosphate buffer solution (pH 7.0). The separation of anodic and cathodic peak potentials is 81 mV, indicating a fast electron transfer reaction. The experimental results also clarified that the immobilized Hb retained its biological activity for the catalysis toward NO. The biosensor showed high sensitivity and fast response upon the addition of NO, under the conditions of pH 7.0, potential -0.82 V. The time to reach the stable-state current was less than 3 s, and the linear response range of NO was 0.72-7.92 μM, with a correlation coefficient of 0.9991.
hemoglobin; graphene; gold nanoparticles; nitric oxide; biosensor
The immunosuppressive agent cyclosporin A has been proven to reduce the rejection rate and prolong the survival time of transplanted hearts. But some reports showed that cyclosporine A did not completely suppress the rejection. We performed in vitro studies to model a time course to observe the effect of cyclosporin A. Methods: The experiment was divided into a control group (group I), an antigen group (group II), a cyclosporin A group (group III) and an antigen + cyclosporin A group (group IV). After transplantation, at 2 h, 6 h, 12 h, 24 h, 48 h and 72 h, leukocyte molecules were monitored. Results: The expression of IL-2R peaked at 12 h in group II and at 6 h in group III. There was a gradual decline in the expression of the P59 gene in group I, positive expression at 2 h and between 12 h and 24 h in group II, in group IV, there was a decrease at 48 h. The expression of the CD4 gene was lowest at 2 h in group I and at 6 h in group II. CD4 expression then quickly increased to a maximum at 48 h in group III, at 2 h in group IV. There was a minimal expression was reached at 12 h in group I and IV and at 6 h in group III in the expression of the CD8 gene. Conclusions: Alloantigen induced lymphocytes to release IL-2R and P59 and stimulated the induction of the CD4 gene’ transcription for 6 h. Cyclosporin A stimulated the release of IL-2R for 2 h. These results provide an in vitro basis for describing the time phases of rejection inhibited by cyclosporin A.
Transplantation rejection model in vitro; early expression’ time phase; cyclosporin A
The present study examined the prevalence and genotypes of Cryptosporidium andersoni in cattle in Shaanxi province, China. A total of 2071 fecal samples (847 from Qinchuan cattle and 1224 from dairy cattle) were examined for the presence of Cryptosporidium oocysts, and 70 samples (3.4%) were C. andersoni-positive and those positive samples were identified by PCR amplification of the small subunit ribosomal RNA (SSU rRNA) and the Cryptosporidium oocyst wall protein (COWP) genes. C. andersoni was the only species found in the examined cattle in this province. Fifty-seven C. andersoni isolates were characterized into 5 MLST subtypes using multilocus sequence typing analysis, including a new subtype in the native beef breed Qinchuan cattle. All of these C. andersoni isolates presented a clonal genetic structure. These findings provide new insights into the genetic structure of C. andersoni isolates in Shaanxi province and basic data of Cryptosporidium prevalence status, which in turn have implications for controlling cryptosporidiosis in this province.
Cyclospora spp. have been identified as one of the most important intestinal pathogens causing protracted diarrhea in animals and human beings. To determine the Cyclospora species in the non-human primate Rhinopithecus roxellanae, a total of 71 fecal samples from 19 endangered snub-nosed monkeys in Shaanxi province were collected and examined using Sheater’s sugar flotation technique and by sequencing the fragments of 18S rDNA. Only two Cyclospora isolates from 2 golden snub-nosed monkeys (R. roxellanae) were obtained and identified between July 2011 and August of 2012. The sequences of the 18S rDNA for the two Cyclospora isolates were 477 bp, with no nucleotide variation between them. Phylogenetic analysis based on the 18S rDNA sequences revealed that the two Cyclospora isolates were posited into the clade Cyclospora spp. and sistered to C. colobi. These results first showed that Cyclospora infection occurred in R. roxellanae in hot and rainy weather, which would provide useful information for further understanding the molecular epidemiology of Cyclospora spp. and the control of Cyclospora infection in non-human primates as well as in human beings.
Despite the wide range of available colorectal cancer (CRC) screening tests, less than 50% of cases are detected at early stages. However, the identification of differentially expressed proteins or novel protein biomarkers in CRC may have some utility and, ultimately, improve patient care and survival. Proteomics combined with mass spectroscopy and liquid chromatography are emerging as powerful tools that have led to the discovery of potential markers in cancer biomarker discovery in several types of cancers. This article describes a novel technology that uses isotopic reagents to tag selected proteins that show a consistent pattern of differential expression in CRC.
To identify and validate potential biomarkers of colorectal adenocarcinoma using a proteomic approach.
Multidimensional liquid chromatography/mass spectrometry was used to analyze biological samples labelled with isobaric mass tags for relative and absolute quantitation to identify differentially expressed proteins in human colorectal adenocarcinoma and paired normal mucosa for the discovery of cancerous biomarkers. Cancerous and noncancerous samples were compared using online and offline separation. Protein identification was performed using mass spectrometry. The downregulation of gelsolin protein in colorectal adenocarcinoma samples was confirmed by Western blot analysis and validated using immunohistochemistry.
A total of 802 nonredundant proteins were identified in colorectal adenocarcinoma samples, 82 of which fell outside the expression range of 0.8 to 1.2, and were considered to be potential cancer-specific proteins. Immunohistochemistry revealed a complete absence of gelsolin expression in 86.89% of samples and a reduction of expression in 13.11% of samples, yielding a sensitivity of 86.89% and a specificity of 100% for distinguishing colorectal adenocarcinoma from normal tissue.
These findings suggest that decreased expression of gelsolin is a potential biomarker of colorectal adenocarcinoma.
Biomarker; Colorectal cancer; Gelsolin; Proteomic
Thioesterases remove the fatty acyl moiety from the fatty acyl-acyl carrier proteins (ACPs), releasing them as free fatty acids (FFAs), which can be further used to produce a variety of fatty acid-based biofuels, such as biodiesel, fatty alcohols and alkanes. Thioesterases play a key role in the regulation of the fatty acid synthesis in Escherichia coli. Therefore, exploring more promising thioesterases will contribute to the development of industrial microbial lipids production.
We cloned and expressed a cytosolic Acinetobacter baylyi thioesterase (‘AcTesA) in E. coli by deleting its leader sequence. Protein sequence alignment, structure modeling and site-directed mutagenesis demonstrated that Ser10, Gly48, Asn77, Asp158 and His161 residues composed the active centre of ‘AcTesA. The engineered strain that overexpressed ‘AcTesA achieved a FFAs titer of up to 501.2 mg/L in shake flask, in contrast to only 20.5 mg/L obtained in wild-type E. coli, demonstrating that the expression of ‘AcTesA indeed boosted the synthesis of FFAs. The ‘AcTesA exhibited a substrate preference towards the C8-C16 acyl groups, with C14:0, C16:1, C12:0 and C8:0 FFAs being the top four components. Optimization of expression level of ‘AcTesA made the FFAs production increase to 551.3 mg/L. The FFAs production further increased to 716.1 mg/L by optimization of the culture medium. Fed-batch fermentation was also carried out to evaluate the FFAs production in a scaleable process. Finally, 3.6 g/L FFAs were accumulated within 48 h, and a maximal FFAs yield of 6.1% was achieved in 12–16 h post induction.
For the first time, an A. baylyi thioesterase was cloned and solubly expressed in the cytosol of E. coli. This leaderless thioesterase (‘AcTesA) was found to be capable of enhancing the FFAs production of E. coli. Without detailed optimization of the strain and fermentation, the finally achieved 3.6 g/L FFAs is encouraging. In addition, ‘AcTesA exhibited different substrate specificity from other thioesterases previously reported, and can be used to supply the fatty acid-based biofuels with high quality of FFAs. Altogether, this study provides a promising thioesterase for FFAs production, and is of great importance in enriching the library of useful thioesterases.
Thioesterase; Acinetobacter baylyi; Escherichia coli; Free fatty acid; Substrate specificity; Active-site residues
Background. Colorectal cancer (CRC) is one of the most common cancers in the world, identification of biomarkers for early detection of CRC represents a relevant target. The present study aims to determine serum peptidome patterns for CRC diagnosis.
Methods. The present work focused on serum proteomic analysis of 32 health volunteers and 38 CRC by ClinProt Kit combined with mass spectrometry. This approach allowed the construction of a peptide patterns able to differentiate the studied populations. An independent group of serum (including 33 health volunteers, 34 CRC, 16 colorectal adenoma, 36 esophageal carcinoma, and 31 gastric carcinoma samples) was used to verify the diagnostic and differential diagnostic capability of the peptidome patterns blindly. An immunoassay method was used to determine serum CEA of CRC and controls. Results. A quick classifier algorithm was used to construct the peptidome patterns for identification of CRC from controls. Two of the identified peaks at m/z 741 and 7772 were used to construct peptidome patterns, achieving an accuracy close to 100% (>CEA, P < 0.05). Furthermore, the peptidome patterns could differentiate validation group with high accuracy.
Conclusions. These results suggest that the ClinProt Kit combined with mass spectrometry yields significantly higher accuracy for the diagnosis and differential diagnosis of CRC.
AIM: To determine the prognostic value of lymphatic and/or blood vessel invasion (LBVI) in patients with stage II gastric cancer.
METHODS: From January 2001 to December 2006, 487 patients with histologically confirmed primary gastric adenocarcinoma were diagnosed with stage II gastric cancer according to the new 7th edition American Joint Committee on Cancer stage classification at the Department of Gastric Cancer and Soft Tissue Surgery, Fudan University Shanghai Cancer Center. All patients underwent curative gastrectomy with standard lymph node (LN) dissection. Fifty-one patients who died in the postoperative period, due to various complications or other conditions, were excluded. Clinicopathological findings and clinical outcomes were analyzed. Patients were subdivided into four groups according to the status of LBVI and LN metastases. These four patient groups were characterized with regard to age, sex, tumor site, pT category, tumor grading and surgical procedure (subtotal resection vs total resection), and compared for 5-year overall survival by univariate and multivariate analysis.
RESULTS: The study was composed of 320 men and 116 women aged 58.9 ± 11.5 years (range: 23-88 years). The 5-year overall survival rates were 50.7% and the median survival time was 62 mo. Stage IIa cancer was observed in 334 patients, including 268 T3N0, 63 T2N1, and three T1N2, and stage IIb was observed in 102 patients, including 49 patients T3N1, 51 T2N2, one T1N3, and one T4aN0. The incidence of LBVI was 28.0% in stage II gastric cancer with 19.0% (51/269) and 42.5% (71/167) in LN-negative and LN-positive patients, respectively. In 218 patients (50.0%), there was neither a histopathologically detectable LBVI nor LN metastases (LBVI−/LN−, group I); in 51 patients (11.7%), LBVI with no evidence of LN metastases was detected (LBVI+/LN−, group II). In 167 patients (38.3%), LN metastases were found. Among those patients, LBVI was not determined in 96 patients (22.0%) (LBVI−/LN+, group III), and was determined in 71 patients (16.3%) (LBVI+/LN+, group IV). Correlation analysis showed that N category and the number of positive LNs were significantly associated with the presence of LBVI (P < 0.001). The overall 5-year survival was significantly longer in LN-negative patients compared with LN-positive patients (56.1% vs 42.3%, P = 0.015). There was a significant difference in the overall 5-year survival between LBVI-positive and LBVI-negative tumors (39.6% vs 54.8%, P = 0.006). Overall 5-year survival rates in each group were 58.8% (I), 45.8% (II), 45.7% (III) and 36.9% (IV), and there was a significant difference in overall survival between the four groups (P = 0.009). Multivariate analysis in stage II gastric cancer patients revealed that LBVI independently affected patient prognosis in LN-negative patients (P = 0.018) but not in LN-positive patients (P = 0.508).
CONCLUSION: In LN-negative stage II gastric cancer patients, LBVI is an additional independent prognostic marker, and may provide useful information to identify patients with poorer prognosis.
Stage II cancer; Gastric cancer; Lymphatic invasion; Blood vessel invasion; Prognosis
With the increasing stress from oil price and environmental pollution, aroused attention has been paid to the microbial production of chemicals from renewable sources. The C12/14 and C16/18 alcohols are important feedstocks for the production of surfactants and detergents, which are widely used in the most respected consumer detergents, cleaning products and personal care products worldwide. Though bioproduction of fatty alcohols has been carried out in engineered E. coli, several key problems have not been solved in earlier studies, such as the quite low production of C16/18 alcohol, the lack of optimization of the fatty alcohol biosynthesis pathway, and the uncharacterized performance of the engineered strains in scaled-up system.
We improved the fatty alcohol production by systematically optimizing the fatty alcohol biosynthesis pathway, mainly targeting three key steps from fatty acyl-acyl carrier proteins (ACPs) to fatty alcohols, which are sequentially catalyzed by thioesterase, acyl-coenzyme A (CoA) synthase and fatty acyl-CoA reductase. By coexpression of thioesterase gene BTE, acyl-CoA synthase gene fadD and fatty acyl-CoA reductase gene acr1, 210.1 mg/L C12/14 alcohol was obtained. A further optimization of expression level of BTE, fadD and acr1 increased the C12/14 alcohol production to 449.2 mg/L, accounting for 75.0% of the total fatty alcohol production (598.6 mg/L). In addition, by coexpression of thioesterase gene ‘tesA, acyl-CoA synthase gene fadD and fatty acyl-CoA reductase gene FAR, 101.5 mg/L C16/18 alcohol was obtained, with C16/18 alcohol accounting for 89.2% of the total fatty alcohol production.
To our knowledge, this is the first report on selective production of C12/14 and C16/18 alcohols by microbial fermentation. This work achieved high-specificity production of both C12/14 and C16/18 alcohols. The encouraging 598.6 mg/L of fatty alcohols represents the highest titer reported so far. In addition, the 101.5 mg/L 89.2% C16/18 alcohol suggests an important breakthrough in C16/18 alcohol production. A more detailed optimization of the expression level of fatty alcohol biosynthesis pathway may contribute to a further improvement of fatty alcohol production.
Fatty alcohol; Escherichia coli; Pathway optimization; Selective production; Fermentation