Establishment and biological characteristics of Luxi cattle fibroblast bank

A fibroblast line from ear marginal tissue of Luxi cattle (LXCEM2/2) was successfully established by direct culturing of explants. Biological analysis showed that the population doubling time (PDT) for reviving cells was approximately 24 h. Measurement of lactic dehydrogenase (LDH) and malic dehydrogenase (MDH) isoenzymes showed no cross-contamination among the cells. Karyotyping showed that the frequency of cells with chromosome number 2n = 60 was 90.7–92.2%. Tests for bacteria, fungi, viruses and mycoplasma were negative. The efficiencies of expression of pEGFP-N3, pEYFP-N1 and pDsRed1-N1 were between 6.3% and 31.6% at 24 h, 48 h and 72 h after transfer; at 24 h, fluorescence was well distributed in the cytoplasm and nucleus except for some cryptomeric vesicles. Every index of the Luxi cattle cell line meets the quality control standards of the American Type Culture Collection (ATCC). Not only has the germline of this important cattle breed been preserved at the cell level, but also valuable material had been provided for genome, postgenome and somacloning research. Moreover, the establishment of this technical platform may provide both technical and theoretical support for storing the genetic resources of other animals and poultry at the cell level.     

Establishment and biological characterization of fibroblast cell line from the Langshan chicken

Objective: We needed to establish an embryonic fibroblast cell line from the Langshan chicken (LSCEF61) to preserve their important genetic resources at the cellular level. Material and methods: The cell line was established from 9‐day‐old embryos by direct explant culture and cryopreservation techniques. Cell morphology, dynamic proliferation and any contamination present were tested, and the karyotype and levels of isoenzymes of lactic dehydrogenase and malic dehydrogenase were analysed. Four types of fluorescent protein exogenous genes for pEGFP‐C₁, pEGFP‐N₃, pEYFP‐N₁ and pDsRed1‐N₁ were transfected into the cells. Results: Showed that the cells were healthy and were of spindle shaped structure, without change in morphology. Cell growth curves were of typical S‐shape. Assays for microbial contamination were negative. The LSCEF61 line showed no cross‐contamination when assessed by isoenzyme analysis. Chromosome number (2n) = 78 on more than 90% of occasions. The four types of fluorescent protein extro‐genes appeared to be expressed effectively with high transfection efficiency between 15.6% and 38.6%. Conclusion: The cell line met each of the quality control standards required for the American Type Culture Collection. It had not only preserved the genetic resources of the important Langshan chicken at the cellular level, but also provided valuable material for genomic, post‐genomic and somatic cell cloning research and other applications.     

Analysis of runs of homozygosity and their relationship with inbreeding in five cattle breeds farmed in Italy

Increased inbreeding is an inevitable consequence of selection in livestock populations. The analysis of high‐density single nucleotide polymorphisms (SNPs) facilitates the identification of long and uninterrupted runs of homozygosity (ROH) that can be used to identify chromosomal regions that are identical by descent. In this work, the distribution of ROH of different lengths in five Italian cattle breeds is described. A total of 4095 bulls from five cattle breeds (2093 Italian Holstein, 749 Italian Brown, 364 Piedmontese, 410 Marchigiana and 479 Italian Simmental) were genotyped at 54K SNP loci. ROH were identified and used to estimate molecular inbreeding coefficients (F_ROH), which were compared with inbreeding coefficients estimated from pedigree information (F_PED) and using the genomic relationship matrix (F_GRM). The average number of ROH per animal ranged from 54 ± 7.2 in Piedmontese to 94.6 ± 11.6 in Italian Brown. The highest number of short ROH (related to ancient consanguinity) was found in Piedmontese, followed by Simmental. The Italian Brown and Holstein had a higher proportion of longer ROH distributed across the whole genome, revealing recent inbreeding. The F_PED were moderately correlated with F_ROH > 1 Mb (0.662, 0.700 and 0.669 in Italian Brown, Italian Holstein and Italian Simmental respectively) but poorly correlated with F_GRM (0.134, 0.128 and 0.448 for Italian Brown, Italian Holstein and Italian Simmental respectively). The inclusion of ROH > 8 Mb in the inbreeding calculation improved the correlation of F_ROH with F_PED and F_GRM. ROH are a direct measure of autozygosity at the DNA level and can overcome approximations and errors resulting from incomplete pedigree data. In populations with high linkage disequilibrium (LD) and recent inbreeding (e.g. Italian Holstein and Italian Brown), a medium‐density marker panel, such as the one used here, may provide a good estimate of inbreeding. However, in populations with low LD and ancient inbreeding, marker density would have to be increased to identify short ROH that are identical by descent more precisely.     

Delayed parturition in cloned calves associated with persistently elevated placentomal TGF-β1 expression

The objective of this study was to investigate hormonal and TGF-β₁ characterizations of delayed parturition in the SCNT recipients (Korean native beef cattle: Hanwoo). The SCNT blastocysts produced by Hanwoo fetal fibroblast cells were transferred into the synchronized Hanwoo recipients. The artificially inseminated Hanwoo recipients (AI-R) were used as control. All AI-R were labored by natural delivery. The SCNT recipients (SCNT-R) with no signs of delivery were operated by Caesarean section. The blood and placentomes were collected during parturition. The weight of placentomes in SCNT-R (n = 12, 301 ± 41.22 g) was significantly higher than that of AI-R (n = 10, 204.8 ± 24.89 g) (p < 0.05). There were significantly lower E2 (p < 0.05) or higher P4 (p < 0.01) and TGF-β₁ (p < 0.01) levels in the SCNT-R compared to that of AI-R, respectively. The SCNT-R showed a higher placentomal TGF-β₁ protein level compared to that of AI-R (p < 0.01). Interestingly, the TGF-β₁ protein level in SCNT-R with normal delivery was dramatically decreased as same as AI-R, but it was highly maintained in C-sec at days 250 of pregnancy in AI-R. These results suggest that delayed parturition in clone calving may be associated with persistence of elevated TGF-beta-1 expression in late pregnancy.     

A genome‐wide association study suggests several novel candidate genes for carcass traits in Chinese Simmental beef cattle

A genome‐wide association study (GWAS) was conducted for two carcass traits in Chinese Simmental beef cattle. The experimental population consisted of 1301 individuals genotyped with the Illumina BovineHD SNP BeadChip (770K). After quality control, 671 990 SNPs and 1217 individuals were retained for the GWAS. The phenotypic traits included carcass weight and bone weight, which were measured after the cattle were slaughtered at 16 to 18 months of age. Three statistical models—a fixed polygene model, a random polygene model and a composite interval mapping polygene model—were used for the GWAS. The genome‐wide significance threshold after Bonferroni correction was 7.44E‐08 (= 0.05/671 990). In this study, we detected eight and seven SNPs significantly associated with carcass weight and bone weight respectively. In total, 11 candidate genes were identified within or close to these significant SNPs. Of these, we found several novel candidate genes, including PBX1, GCNT4, ALDH1A2, LCORL and WDFY3, to be associated with carcass weight and bone weight in Chinese Simmental beef cattle, and their functional roles need to be verified in further studies.     

Development of desiccation tolerance and vitrification by preculture treatment in suspension-cultured cells of the liverwort Marchantia polymorpha

Some cultured plant cells are able to acquire tolerance to various stresses when they are cultured under suitably controlled conditions. Induction of a high level of desiccation tolerance in suspension-cultured cells of the liverwort Marchantia polymorpha was examined for studying the mechanisms of desiccation tolerance and vitrification at the cellular level. Desiccation tolerance level of cells was very low and the survival rate was less than 10% after exposure to drying below 0.1 g H₂O g⁻¹ dry weight (DW). Preculture treatment in 0.5 M sucrose medium was the most effective method for inducing a high level of desiccation tolerance in cells and the survival rate was 87% even after being desiccated to below 0.1 g H₂O g⁻¹ DW. Preculture treatment caused alteration of cell structures and accumulation of a large amount of sucrose and newly synthesized proteins in cells. Abundant sucrose and preculture-induced proteins were necessary for full development of desiccation tolerance in the cells. When water content decreased to below 0.1 g H₂O g⁻¹ DW, desiccation-tolerant cells that had been precultured were vitrified above 0°C and maintained stable viability. We have succeeded in the induction of desiccation tolerance that allows formation of intracellular glass with cell viability at ambient temperatures by controlling culture conditions, and our results suggest that suspension-cultured cells of M. polymorpha are useful for studying cellular mechanisms for the development of desiccation tolerance and the stabilization of vitrified cells.     

Association of SCD1 and DGAT1 SNPs with the intramuscular fat traits in Chinese Simmental cattle and their distribution in eight Chinese cattle breeds

Intramuscular fat (IMF) is a key parameter for evaluation of nutritional quality of beef, with its endogenous synthesis regulated by stearoyl CoA desaturase (SCD1) and diacylglycerol-acyl transferase 1 (DGAT1) genes in cattle. The object of this research was to evaluate the effect of SCD1 and DGAT1 polymorphisms on IMF trait in beef cattle and to estimate the frequency distribution of SNPs in the two genes in Chinese cattle populations. The SCD1 and DGAT1 polymorphisms were detected by PCR-single strand conformation polymorphism (PCR-SSCP) method in Chinese Simmental cattle and their associations with IMF traits were analyzed using the general linear model (GLM). The frequency distribution of SNPs in SCD1 and DGAT1 genes were detected by PCR-SSCP method and analyzed in seven other cattle populations. The results showed significant associations of SNPs SCD1-878, SCD1-762, and DGAT1 10433 and 10434 with IMF (%) and shearing force values (SFV; kg) in Chinese Simmental cattle. A haplotype combining SCD1-878C, SCD1-762T, and DGAT1 10433 and 10434-GC had the highest IMF, marbling score and shearing force. The polymorphic investigation indicated that the frequency of SCD1-878C or SCD1-762T was significantly higher in Chinese southern cattle (Leiqiong, Yunnan High pump, BMY or Minnan Cattle) than in Chinese northern cattle (Chinese Simmental, Luxi Cattle, Bohai Black or Chinese Holstein), while the frequency of DGAT1 10433 and 10434-GC in Chinese indigenous breed (Leiqiong, Yunnan High pump, BMY, Luxi Cattle, Bohai Black, or Minnan Cattle) was significantly lower than breeds with imported blood (Chinese Simmental or Chinese Holstein). These findings demonstrated that both the SCD1 and DGAT1 SNPs were prospect genetic markers for IMF traits, and the SCD1 SNPs could be used as a genetic marker for southern or northern blood in Chinese cattle.     

Functional Characteristics of <Emphasis Type="Italic">Lactobacillus</Emphasis><Emphasis Type="Italic">fermentum</Emphasis> F1

In this study, Lactobacillus fermentum (L. fermentum) F1 reduced cholesterol 48.87%. The strain was screened from cattle feces using an API 50 CHL system and the 16S rRNA sequence contrasting method. L. fermentum F1 showed acid and bile tolerance, and antimicrobial activity against pathogenic Escherichia coli and Staphylococcus aureus. L. fermentum F1 deconjugated 0.186 mM of free cholalic acid after it was incubated at 37°C in 0.20% sodium taurocholate (TCA) broth for 24 h. Heat-killed and resting cells of L. fermentum F1 showed small amounts of cholesterol removal (6.85 and 25.19 mg/g, respectively, of dry weight) compared with growing cells (33.21 mg/g of dry weight). The supernatant fluid of the broth contained 50.85% of the total cholesterol, while the washing buffer and cell extracts had 13.53 and 35.39%, respectively. These findings suggest that L. fermentum F1 may remove cholesterol by co-precipitating with deconjugated bile salt, assimilating with cells and by incorporation into cellular membranes. Cholesterol assimilated by cells held 72.0% of the reduced cholesterol, while 21.65% of the reduced cholesterol was coprecipitated with deconjugated bile salt and 5.89% was adsorbed into the surface of the cells.     

Optimization of square-wave electroporation for transfection of porcine fetal fibroblasts

Development of a transgenic porcine biomedical research model requires effective delivery of DNA into the donor cell followed by selection of genetically modified somatic cell lines to be used for nuclear transfer. The objective of the current study was 2-fold: (1) to compare the effectiveness of a single 1 ms pulse of different voltages (V; 100, 150, 200, 250, 300, 350) and multiple 1 ms pulses (1, 2, 3, 4 or 5) at 300 V for delivery and expression of super-coiled GFP vector in surviving cells of three fetal fibroblast cell lines, and (2) to determine the ability of these electroporation parameters to produce stably transfected fibroblast colonies following G418 selection. Cell line (P < 0.001) and voltage (P < 0.001) affected DNA delivery into the cell as assessed by GFP expression while survival at 24 h was affected by voltage (P < 0.001) and not by cell line (P = 0.797). Using a single pulse while increasing voltage resulted in the percentage of GFP expressing cells increasing from 3.2 ± 0.8% to 43.0 ± 3.4% while survival decreased from 90.5 ± 8.0% to 44.8 ± 2.0%. The number of pulses at 300 V significantly affected survival (P < 0.001) and GFP expression (P < 0.001). Survival steadily decreased following 1–5 pulses from 63.2 ± 6.3% to 3.0 ± 0.3% with GFP expression of surviving cells increasing from 35.6 ± 2.67% to 71.4 ± 6.1%. Electroporation of a selectable marker at a 1:1 copy number ratio to a co-electroporated transgene resulted in 83% of G418 resistant colonies also being PCR positive for the secondary transgene. These electroporation conditions, specifically, three 1 ms pulses of 300 V to 200 μL of 1 × 10⁶ cells/mL in the presence of 12.5 μg DNA/mL effectively introduced DNA into somatic cells. The utilization of these conditions produced numerous transgenic fibroblast colonies following G418 selection that when used for somatic cell nuclear transfer resulted in the production of live offspring.     

Nutrient regulation of bacterial growth and production of anti-tumor metabolites in <Emphasis Type="Italic">Stigmatella</Emphasis> WXNXJ-B fermentation

The metabolites produced by Stigmatella WXNXJ-B inhibited the growth of tumor cells. The aims of this research were to evaluate the inhibition potency to different tumor cell lines and to study the effects of ammonium, phosphate and iron salts on bacterial growth and production of bioactive metabolites in Stigmatella WXNXJ-B fermentation. The results showed that the chloroform extract (CE-ME) showed the strongest growth inhibition bioactivity on mouse melanoma cell line (B16), murine colon carcinoma cell line (CT-26), human liver carcinoma cell line (HepG2) and human breast cancer cell line (MDA-MB231) in vitro and the IC₅₀ values were 9.94, 7.33, 11.34 and 11.66 μg ml⁻¹ respectively. The IC₅₀ value was above 700 μg ml⁻¹ on normal mouse spleen cells. Morphology happened changes in B16 cells treated with CE-ME. The anti-tumor metabolites were mainly produced during the stationary phase of the bacterial growth. Cell growth was stimulated at the phosphate concentration below 5 mM, but it was inhibited partly with 10 mM phosphate. The production of bioactive substances was inhibited by the phosphate. Ammonium increased the cell growth by 250% at 5 mM addition. The inhibition rate to B16 cells was increased to 89% at the concentration of 40 mM ammonium. The bacteria showed the best growth with 4 mM iron. Iron had little effect on the production at 2 mM, but bigger inhibition effect at higher iron concentration.     

In vivo characterization of transplanted human embryonic stem cell‐derived pancreatic endocrine islet cells

Abstract. Objectives: Islet‐like clusters (ILCs), differentiated from human embryonic stem cells (hESCs), were characterized both before and after transplantation under the kidney capsule of streptozotocin‐induced diabetic immuno‐incompetent mice. Materials and methods: Multiple independent ILC preparations (n = 8) were characterized by immunohistochemistry, flow cytometry and cell insulin content, with six preparations transplanted into diabetic mice (n = 42), compared to controls, which were transplanted with either a human fibroblast cell line or undifferentiated hESCs (n = 28). Results: Prior to transplantation, ILCs were immunoreactive for the islet hormones insulin, C‐peptide and glucagon, and for the ductal epithelial marker cytokeratin‐19. ILCs also had cellular insulin contents similar to or higher than human foetal islets. Expression of islet and pancreas‐specific cell markers was maintained for 70 days post‐transplantation. The mean survival of recipients was increased by transplanted ILCs as compared to transplanted human fibroblast cells (P < 0.0001), or undifferentiated hESCs (P < 0.042). Graft function was confirmed by secretion of human C‐peptide in response to an oral bolus of glucose. Conclusions: hESC‐derived ILC grafts continued to contain cells that were positive for islet endocrine hormones and were shown to be functional by their ability to secrete human C‐peptide. Further enrichment and maturation of ILCs could lead to generation of a sufficient source of insulin‐producing cells for transplantation into patients with type 1 diabetes.     

Effect of thermal stress on HSP70 expression in dermal fibroblast of zebu (Tharparkar) and crossbred (Karan-Fries) cattle

The present studies were conducted to investigate the difference response of dermal fibroblasts to heat stress in Tharparkar and Karan-Fries cattle. Skin is the most important environmental interface providing a protective envelope to animals. In skin, dermal fibroblasts are the most regular cell constituent of dermis that is crucial for temperature homeostasis. The study aimed to examine the reactive oxygen species (ROS) formation, cytotoxicity (%) and heat shock protein 70 (HSP70) genes expression in dermal fibroblast of Tharparkar and Karan-Fries cattle and to assess whether resistance of dermal fibroblast to heat stress is breed specific. Dermal fibroblasts from ear pinna of Tharparkar and Karan-Fries cattle were exposed at 25 °C, 37 °C, 40 °C and 44 °C for 3 h to measure the ROS, cytotoxicity (%) and HSP 70 (HSPA1A, HSPA2 and HSPA8) genes’ expression. The results showed that ROS formation at low temperature (25 °C) decreased in both breeds as compared to control (37 °C) and the differences were significant (P<0.0001). Heat stress at 40 °C did not increase ROS formation significantly in Tharparkar but increased significantly (P<0.001) in Karan-Fries cattle. The overall cytotoxicity (%) was also found to be significantly different (P<0.001) between Tharparkar and Karan-Fries cattle, and on exposure to different temperatures (P<0.001). The cytotoxicity (%) in dermal fibroblast cells of Karan-fries cows was more than Tharparkar. The expression studies indicated that all HSP70 genes (HSPA8, HSPA1A and HSPA2) were up-regulated at different temperatures in both breeds. In Tharparkar, the relative mRNA expression of HSPA8 gene was higher but HSPA1A and HSPA2 genes were low as compared to Karan-Fries cattle. At 40 and 44 °C, the relative expressions of inducible HSP 70 genes (HSPA1A and HSPA2) were higher in Karan-Fries than Tharparkar. In summary, dermal fibroblast resistance to heat shock differed between breeds. Dermal fibroblasts of Tharparkar were observed to be more heat tolerant than crossbred Karan-Fries cattle. The study concludes that zebu cattle (Tharparkar) dermal fibroblasts are more adapted to tropical climatic condition than crossbreed cattle (Karan-Fries). Differences exist in dermal fibroblasts of heat adapted and non-adapted cattle.     

Enhanced 5-HT<Subscript>2A</Subscript> Receptors in Brain Stem and ALDH Activity in Brain Stem and Liver: 5-HT<Subscript>2A</Subscript> Regulation on ALDH in Primary Hepatocytes Cultures In Vitro

Brain serotonin (5-HT) modulates the neural effects of ethanol. In the present study, we investigated the changes in 5-HT level, 5-HT_2A receptor binding and aldehyde dehydrogenase (ALDH) activity in brain stem and liver of ethanol treated rats and 5-HT_2A regulation on ALDH in hepatocyte cultures in vitro. The 5-HT content in the brain stem and liver significantly decreased with an increased 5-HIAA/5-HT ratio in the ethanol treated rats compared to control. Scatchard analysis of [³H] (±)2,3-dimethoxyphenyl-1-[2-(-4-piperidine)-methanol] [³H] MDL 100907 against ketanserin in brain stem of ethanol treated rats showed a significant increase in B _max without any change in K _d compared to control. The competition curve for [³H] MDL 100907 against ketanserin fitted one-site model in both control and ethanol treated rats with unity as Hill slope value. A significant increase in V _max of ALDH activity in liver and a significant decrease in K _m in liver and brain stem of ethanol treated rats compared to control was observed. In 24 h culture studies, an increase in enzyme activity was observed in cells in medium with 10% ethanol. The elevated ALDH activity in ethanol treated cells was reversed to control level in presence of 10⁻⁵ and 10⁻⁷ M 5-HT. Ketanserin, an antagonist of 5-HT_2A, reversed the effect of 5HT on 10% ethanol induced ALDH activity in hepatocytes. Our results showed that there was a decreased 5-HT content with an enhanced 5-HT_2A receptor and aldehyde dehydrogenase activity in the brain stem of alcohol treated rats and in vitro hepatocyte cultures. The enhanced ALDH activity in ethanol supplemented hepatocytes was reversed to control level in presence of 10⁻⁵ and 10⁻⁷ M 5-HT.     

Molecular Cloning of Bovine FABGL Gene and Its Effects on Bovine Bioeconomic Traits

The complete CDS sequence of the bovine FABGL gene was determined by homology cloning approach combined with RT-PCR and 3′- and 5′-RACE. The results of sequence analysis and bioinformatics study showed that this cDNA contained 994 nucleotides, with a 780 bp open reading frame (ORF) flanked by a 16 bp 5′-UTR (incompletely) and a 198 bp 3′-UTR. The deduced amino acid sequence (260 AA) shows 88% identity with the corresponding sequence in humans. Two single nucleotide substitutions, one located in intron 5 (I5) at position 1 065 bp (Y = C/T) (GenBank: DQ409814) and the other in intron 8 (I8) at position 1 792 bp (R = A/G), were detected using the PCR-SSCP method. Analysis of the allele frequencies of the two polymorphic sites in three different cattle breeds (Angus, Hereford, and Simmental) with different genotypes showed large differences: in locus I8, cattle with the GG genotype showed higher beef performance index (BPI) (4.283 ± 0.475 kg/cm) in comparison with cattle with the AA genotype (4.008 ± 0.465 kg/cm) (P = 0.01). Regarding the ribeye area, cattle with the GG genotype showed significantly higher ribeye area (73.380 ± 13.005 cm²) compared with cattle with the AA genotype (67.744 ± 12.777 cm²) (p = 0.05). In locus I5, some associations for the average daily gain (ADG) were found at the significance level of 0.01 between three different genotypes (CC, CT, TT): cattle with the TT genotype showed the highest ADG (0.652 ± 0.330 kg/d), whereas cattle with the CC genotype showed the lowest ADG value (0.421 ± 0.178 kg/d).     

Toxicity of phospholipases A<Subscript>2</Subscript> D49 (6-1 and 6-2) and K49 (Bj-VII) from <Emphasis Type="Italic">Bothrops jararacussu</Emphasis> venom

Purified phospholipase A₂ (PLA2) enzymes from Bothrops jararacussu snake venom were examined to evaluate NIH 3T3 and COS7 fibroblast cytotoxicity, as well as muscle myotoxic and inflammatory activities. Separation of fractions Bj-VII (from BthTX-I; a Lys49 PLA2 homolog) and 6-1 and 6-2 (from BthTX-II; an Asp49 PLA2) from B. jararacussu snake venom by SDS-PAGE in tricine buffer in the absence and presence of dithiothreitol revealed a homodimer with an estimated molecular mass of ∼30 kDa (monomer mass ∼15 kDa). This finding indicates that these toxins form dimeric complexes—a previously reported tendency among PLA2s. These toxins were assayed for viability with the MTT assay, which is used to examine the effects of phospholipases on the mitochondrial viability of cells. The toxins were also assayed for cytolysis of the fibroblast cell lines NIH 3T3 and COS7 by quantification of lactate dehydrogenase released into the medium. The results indicate that the PLA2s 6-1, 6-2 and the Bj-VII PLA2 homolog studied here induce moderate footpad edema and local myotoxicity. Moreover, exposure to these phospholipases led to a reduction in fibroblast viability; at the 1 μM dose of PLA2 tested, a reduction of 50% in cell viability was observed. The present findings indicate that the inflammatory activity observed in envenomation may be correlated with the cytotoxicity observed in fibroblasts.     

Establishment and biological characteristics of Ujumqin sheep fibroblast line

A Ujumqin sheep ear marginal tissue (USEM) fibroblast line, frozen in 147 cryovials with 4 × 10⁶ cell each, was successfully established from 33 Ujumqin sheep ear marginal tissues using explant culture and cryopreservation techniques. The cells were morphologically consistent with fibroblasts. The growth curve was typical S-shape and the cell population passed through a lag phase, a logarithmic phase and a plateau phase. The population doubling time (PDT) was approximately 72 h. Tests for bacteria, fungi, viruses and mycoplasma were all negative. Isoenzyme polymorphism indicated that the genetic characteristics of the cell line were stable in vitro. Karyotyping analysis indicated that the chromosome number of a normal cell was of 2n = 54 and 95.4% of the entire population was diploid. The transfection efficiencies of six fluorescent proteins (pEGFP-N3, pEGFP-C1, pDsRed-N1, pEYFP-N1, pECFP-N1 and pECFP-mito) optimal at 48 h were from 18.5% to 30.1%. The cell line met all criteria from the American Type Culture Collection (ATCC). Not only has the germline of this important sheep breed been preserved at the cell level, but also valuable material had been provided for genome, postgenome and somatic cloning research. Moreover, the establishment of this technical platform may provide both technical and theoretical support for storing the genetic resources of other animals and poultry at the cell level.     

Establishment and characterization of a fibroblast cell line derived from Jining Black Grey goat for genetic conservation

An ear marginal fibroblast cell bank was established from the Jining Black Grey (JBG) goat using attachment culture and freezing biotechniques. This bank included 32 ear samples (15 males and 17 females) and has stocks of 168 cryogenically preserved vials, each vial contained 4.0 × 10⁶ cells per milliliter. The cells of the bank that were checked for the quality and the biological characteristics showed a typical fibroblast morphology when they cultured in vitro. The growth curve consisted of a growth curve consisting of a latent phase, logarithmic growth phase and stationary phase, cell population doubling time (PDT) of 48 h. The chromosome analysis showed that the frequency of cells having the diploid number of chromosomes (60) was 98.65 ± 2.89%, and no microbe contamination (bacteria, epiphyte, virus or mycoplasma) was detected. In addition, lactate dehydrogenase (LDH) and malate dehydrogenase (MDH) zymography indicated that this cell bank was free of cross-contamination. At 24, 48 and 72 h after transfection, the expression efficiency of pEGFP-C1, pEGFP-N3, pEYFP-N1, pECFP-N1, pECFP-mito and pDsRed1-N1 were between 11.8% and 56.3%. The fluorescence could be observed well-distributed in cytoplasm and nucleus except for some cryptomere vesicles at 24 h after transfection. These newly established cell lines meet all the quality control standards established by the American Type Culture Collection. We have employed a new method for conserving the genetic resources of an important and endangered animal breed. The fibroblast bank that we have established from the JBG goat also provides an invaluable material resource for future studies that will utilize molecular and cell biology applications.     

A novel <Emphasis Type="SmallCaps">l</Emphasis>-aspartate dehydrogenase from the mesophilic bacterium <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> PAO1: molecular characterization and application for <Emphasis Type="SmallCaps">l</Emphasis>-aspartate production

l-aspartate dehydrogenase (EC 1.4.1.21; l-AspDH) is a rare member of amino acid dehydrogenase superfamily and so far, two thermophilic enzymes have been reported. In our study, an ORF PA3505 encoding for a putative l-AspDH in the mesophilic bacterium Pseudomonas aeruginosa PAO1 was identified, cloned, and overexpressed in Escherichia coli. The homogeneously purified enzyme (PaeAspDH) was a dimeric protein with a molecular mass of about 28 kDa exhibiting a very high specific activity for l-aspartate (l-Asp) and oxaloacetate (OAA) of 127 and 147 U mg⁻¹, respectively. The enzyme was capable of utilizing both nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP) as coenzyme. PaeAspDH showed a T _m value of 48°C for 20 min that was improved to approximately 60°C by the addition of 0.4 M NaCl or 30% glycerol. The apparent K _m values for OAA, NADH, and ammonia were 2.12, 0.045, and 10.1 mM, respectively; comparable results were observed with NADPH. The l-Asp production system B consisting of PaeAspDH, Bacillus subtilis malate dehydrogenase and E. coli fumarase, achieved a high level of l-Asp production (625 mM) from fumarate in fed-batch process with a molar conversion yield of 89.4%. Furthermore, the fermentative production system C released 33 mM of l-Asp after 50 h by using succinate as carbon source. This study represented an extensive characterization of the mesophilic AspDH and its potential applicability for efficient and attractive production of l-Asp. Our novel production systems are also hopeful for developing the new processes for other compounds production.