Short communication: Microbiological quality of raw cow milk and its association with herd management practices in Northern China

Contamination of raw milk with bacterial pathogens is potentially hazardous to human health. The aim of this study was to evaluate the total bacteria count (TBC) and presence of pathogens in raw milk in Northern China along with the associated herd management practices. A total of 160 raw milk samples were collected from 80 dairy herds in Northern China. All raw milk samples were analyzed for TBC and pathogens by culturing. The results showed that the number of raw milk samples with TBC <2 × 10⁶ cfu/mL and <1 × 10⁵ cfu/mL was 146 (91.25%) and 70 (43.75%), respectively. A total of 84 (52.50%) raw milk samples were Staphylococcus aureus positive, 72 (45.00%) were Escherichia coli positive, 2 (1.25%) were Salmonella positive, 2 (1.25%) were Listeria monocytogenes positive, and 3 (1.88%) were Campylobacter positive. The prevalence of S. aureus was influenced by season, herd size, milking frequency, disinfection frequency, and use of a Dairy Herd Improvement program. The TBC was influenced by season and milk frequency. The correlation between TBC and prevalence of S. aureus or E. coli is significant. The effect size statistical analysis showed that season and herd (but not Dairy Herd Improvement, herd size, milking frequency, disinfection frequency, and area) were the most important factors affecting TBC in raw milk. In conclusion, the presence of bacteria in raw milk was associated with season and herd management practices, and further comprehensive study will be powerful for effectively characterizing various factors affecting milk microbial quality in bulk tanks in China.

Analysis of POU1F1 gene DdeI polymorphism in Chinese goats

As a member of the POU-domain family, the POU1F1 is a positive regulator for growth hormone, prolactin and thyroid-stimulating hormone b, by binding to target DNA promoters as a dimer in mammals. This study described the polymorphisms at the goat POU1F1-DdeI locus and analyzed the distribution of alleles in 15 indigenous Chinese goat breeds. The PCR-RFLP analysis showed a predominance of the D1D1 genotype and the D1 allele, with average frequencies of 0.550 and 0.790, respectively, irrespective of goat utility type. The D1D2 genotype was the second most frequent, with a mean frequency of 0.371. The distributions of genotypic and allelic frequencies at this locus were found to be significantly different among populations based on a Chi square test (P < 0.001), suggesting that the breed factor significantly affected the molecular genetic character of the POU1F1 gene. The genetic diversity analysis revealed that Chinese indigenous populations had a wide spectrum of genetic diversity at the goat POU1F1-DdeI locus. However, an ANOVA analysis revealed no significant differences in gene homozygosity, gene heterozygosity, effective allele numbers, or polymorphism information content among meat, dairy, and cashmere utility types (P > 0.05). This suggests that the goat utility types had no significant effect on the spectrum of genetic diversity.

TMPyP4-regulated cell proliferation and apoptosis through the Wnt/β-catenin signaling pathway in SW480 cells

BACKGROUND

The aim of this study was to investigate the potential effects of the 5, 10, 15, 20-tetrakis (1-methylpyridinium-4-yl) porphyrin (TMPyP4) on the proliferation and apoptosis of SW480 cells and the underlying mechanisms by which TMPyP4 exerted its actions.

METHODS

After treated with different doses of TMPyP4, cell viability was determined by MTT method, the apoptosis was observed by flow cytometry (FCM) and the expression of Wnt, GSK-3β, β-catenin and cyclinD1 was measured by RT-PCR and Western blot analysis.

RESULTS

The analysis revealed that TMPyP4 potently suppressed cell viability and induced the apoptosis of SW480 cells in a dose-dependent manner. In addition, the downregulation of Wnt, β-catenin and cyclinD1 expression levels was detected in TMPyP4-treated SW480 cells. However, followed by the block of Wnt signaling pathway using siRNA methods, the effects of TMPyP4 on proliferation and apoptosis of SW480 cells were significantly reduced.

CONCLUSION

It indicates that the TMPyP4-inhibited proliferation and -induced apoptosis in SW480 cells was accompanied by the suppression of Wnt/β-catenin signaling pathway. Therefore, TMPyP4 may represent a potential therapeutic method for the treatment of colon carcinoma.

Global transcriptional profiling of longissimus thoracis muscle tissue in fetal and juvenile domestic goat using RNA sequencing

Domestic goats are important meat production animals; however, data from transcriptional profiling of skeletal muscle tissue in goat have thus far been scarce. We used comparative transcriptional profiling based on RNA sequencing of longissimus thoracis muscle tissue obtained from fetal goat muscle tissue (27 512 850 clean cDNA reads) and 6-month-old goat muscle tissue (27 582 908 reads) to identify genes that are differentially expressed, novel transcript units and alternative splicing events. Gene annotation revealed that 15 960 and 14 981 genes were expressed in the fetal and juvenile libraries respectively. We detected 6432 differentially expressed genes and, when considering GO terms, found 34, 27 and 55 terms to be significantly enriched in molecular function, cellular component and biological process categories respectively. Pathway analysis revealed that larger numbers of differentially expressed genes were enriched in fetal myogenesis or cell proliferation and differentiation-related pathways (such as Wnt), genes involved in the cell cycle and the Notch signaling pathway, and most of the differentially expressed genes involved in these pathways were downregulated in the juvenile goat library. These genes may be involved in various regulation mechanisms during muscle tissue differentiation between the two development stages examined herein. The identified novel transcript units, including both non-coding and coding RNA, as well as alternative splicing events increase the level of complexity of regulation mechanisms during muscle tissue formation and differentiation. Our study provides a comparative transcriptome analysis on goat muscle tissue, which will provide a valuable genomic resource for future studies investigating the molecular basis of skeletal muscle development.

Effects of CSN1S2 Genotypes on Economic Traits in Chinese Dairy Goats

The aim of this study was to investigate allele frequencies at the CSN1S2 locus in two Chinese dairy goat breeds and the effects of its variation on dairy goat economic traits. Seven hundred and eight goats from Xinong Saanen (XS, n = 268) and Guanzhong (GZ, N = 440) breeds were selected. The milk samples of 268 XS goats were collected during the middle of lactation, body size parameters (708 goats) and daily milk yield (202 goats) were registered. The RFLP (restriction fragment length polymorphism) and SSCP (single strand conformation polymorphism) were used to detect the polymorphisms in CSN1S2. The Hardy-Weinberg (HW) equilibrium and the associations between body size, milk yield and composition and the genotypes were calculated. The results revealed that only A and F CSN1S2 alleles were found in the two Chinese dairy goat breeds. Allelic frequencies of A and F were 0.795, 0.205 and 0.739, 0.261 in Xinong Saanen and Guanzhong population respectively. Xinong Saanen breed was in Hardy-Weinberg equilibrium, while Guanzhong breed deviated from Hardy-Weinberg equilibrium (p<0.05). The association of polymorphism with economic traits indicated that the goats with FF genotype have higher milk fat and total solid concentration than those with AA and AF genotypes (p<0.05).

[Developmental expression patterns and association study with growth traits of bovine]

As a member of the basic helix-loop-helix (bHLH) family of transcription factors, Bhlhe40 played an important role in the regulation of adipogenesis, myogenesis and the development of metabolic syndrome. In this study, we investigated the tissue expression patterns and differences of bovine Bhlhe40 gene during three developmental stages. The result showed that Bhlhe40 was ubiquitously expressed in most tissues of cattle. In addition, the expression of bovine Bhlhe40 gene showed a decreasing trend in skeletal muscle and fat during the de- velopmental stages. Then, two novel mutations (EX5 + 114 T>C, L166P and EX5 + 733 A>G, S372S) of bovine Bhlhe40 gene were identified by BamHI and ApaI ACRS PCR-RFLP in 1226 individuals from five indigenous cattle breeds in China. Frequencies of allele C at the BamHI locus varied from 0.210 to 0.340 among breeds, while frequencies of allele G at the ApaI locus varied from 0.030 to 0.114. Association analysis revealed no significant association of ApaI locus with growth traits in Nanyang breed. However, BamHI locus was significantly associated with the average daily lain at 18 months in Nanvans cattle (P < 0.05). This study aimed to lay the groundwork to further study of Bhlhe40 function at myogenesis and adipogenesis in bovine and should significantly contribute to cattle breeding and genetics through MAS program.

Genetic diversity of mitochondrial cytochrome b gene in Chinese native buffalo

The origins of the domestic water buffalo remain contentious. To better understand the origins of Chinese water buffalo, we sequenced the complete mitochondrial cytochrome b (MT-CYB) gene from 270 individuals representing 13 Chinese domestic swamp buffalo populations. We found genetic evidence of introgression of river buffalo into Chinese swamp buffalo herds. Swamp buffalo haplotypes can be divided into two highly divergent lineages (A and B), suggesting that Chinese native swamp buffalo have two maternal origins. We found that the A→G transition in the buffalo MT-CYB gene stop codon resulted in buffalo haplotypes being terminated by one of two stop codons: AGA or AGG. AGA is common to river buffalo and lineage A of swamp buffalo, while AGG is specific to lineage B of swamp buffalo. Lineage A appears to have been domesticated in China. Further genetic evidence is required to clarify the origins of lineage B.

Novel mutation in TGA stop-codon of bovine SIX6 gene

As a transcriptional regulatory gene of the SIX family, SIX6 (also known as OPTX2, SIX9), probably affects pituitary development and secretion of hormones, suggesting that this gene is a potential candidate gene for studying association with growth trait in animals. Therefore, this study is first of all focused on detecting sequence variations in a bovine SIX6 gene and on its effects on growth traits in 1087 cattle from five Chinese cattle breeds using DNA sequencing and HhaI-ACRS-PCR methods. Herein, a novel mutation (NC_007308: g 2015T > C) in the TGA stop-codon of a bovine SIX6 gene was found, which leads to an ORF shift and extension of the encoded protein for four amino acids (Arg223-Gln224-Arg225-Val226). The frequency of allele "C" varied from 0.255 (Chinese Holsteins) to 0.614 (Hasake). They all were in the Hardy-Weinberg equilibrium except Jiaxian Red and Hasake cattle. Using amino acid sequence alignment and online prediction software, a new helix in the C-terminal domain of the mutated bovine SIX6 protein was revealed, which possibly affects pituitary development and hormone secretion. So, relationship analysis between this polymorphism and growth traits in the Nanyang breed was carried out based on a proper linear model. Although no statistically significant associations were observed (P > 0.05), the presented work preliminarily demonstrated a novel mutation in the TGA stop-codon which extends the spectrum of genetic variations of the bovine SIX6 gene and might be of interest in terms of its association with other biophysical and biochemical indexes.

The CSN1S1 N and F alleles identified by PCR-SSCP and their associations with milk yield and composition in Chinese dairy goats

A method was depicted to identify null allele CSN1S1 N and low allele CSN1S1 F of the CSN1S1 gene of goat using PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism). First, primer A was designed to amplify the exon 9 of CSN1S1 gene which produced three genotypes AA, AB, and BB. Among these three genotypes, only AA and AB individuals had a cytosine deletion at exon 9 after DNA sequencing, which cannot be used to identify the N and F alleles. Therefore, primer B was used to amplify intron 14 of CSN1S1 of described AA and AB individuals. Genotypes FF, FN and NN were detected within AA individuals and genotypes FO and NO were detected in the above AB individuals. The frequencies of F and N alleles in 708 samples from Xinong Saanen (XS) and Guanzhong (GZ) dairy goat breeds were 0.1139, 0.0927, and 0.2376, 0.1193, respectively. In 268 XS samples, the individuals with NN genotype contained a significant lower protein content than that of other genotypes (P<0.01). Individuals of FF genotype had significant higher milk yield than that of NO genotype in the first milk lactation of 202 XS individuals (P<0.05). Therefore, the variability at CSN1S1 locus contains enough genetic diversity to be potentially useful in improving the quality and production of milk in Chinese dairy goat breeds.

A novel polymorphism of the lactoferrin gene and its association with milk composition and body traits in dairy goats

Milk composition and body measurement traits, influenced by genes and environmental factors, play important roles in value assessments of efficiency and productivity in dairy goats. Lactoferrin (LF), involved in the efficient expression of protein in milk, is also an anabolic factor in skeletal tissue and a potent osteoblast survival factor. Therefore, it is an important candidate gene for milk composition and body measurement trait selection in marker-assisted selection. We employed PCR-SSCP and DNA sequencing to screen the genetic variations of the LF gene in 549 Chinese dairy goats. A novel single-nucleotide polymorphism (SNP) (G198A in exon II) of the LF gene was detected. The frequencies of the AA genotype were 0.0285 and 0.0261 in GZ and SN populations, respectively. Both populations were found to have low levels of polymorphism and were in Hardy-Weinberg disequilibrium (P < 0.05). We found significant (P < 0.05) associations of the SNP marker with milk protein and acidity in the total population; animals with the AA genotype had higher mean values for milk protein than those with the GA genotype. Animals with genotype AA had higher mean values for withers height than those with genotype GG (P < 0.05). We concluded that this SNP of the LF gene has potential as a genetic marker for milk composition and body traits in dairy goat breeding.

S-novel SNP of alpha-lactalbumin gene in chinese dairy goats

The alpha-lactalbumin (alpha-LA) plays a key role in lactose synthesis in mammary glands of domestic animals. Mutations in the alpha-LA gene are associated with the milk traits in dairy cattle. In our study, a novel SNP: NO_X06366:g.875 C > T was detected in 708 dairy goat individuals--268 of the Xinong Saanen breed and 440 of Guanzhong breed, which revealed a synonymous mutation in the exon 1 of alpha-LA gene. The Polymerase Chain Reaction-Single Strand Conformation Polymorphism (PCR-SSCP) and sequencing techniques showed that there were three genotypes: CC, CT and TT. Moreover, the chi2-test showed that the genotype frequencies of the two breeds were in good agreement with the Hardy-Weinberg equilibrium (P > 0.05). The relationship of the polymorphism of dairy goat alpha-LA gene with the milk trait and the body size trait was revealed. Individuals with the CC genotype were significantly smaller at chest circumference than those with CT (P < 0.05) in both breeds. But the milk trait and other body size traits of the two dairy goat breeds had no significant association with genotypes studied.

Two novel SNPs in the coding region of the bovine PRDM16 gene and its associations with growth traits

As a zinc-finger protein, PR domain containing 16 (PRDM16) controls brown fat determination by stimulating brown fat-selective genes expression while suppressing the expression of genes selective for white fat cells, whose mutations were associated with myelodysplastic syndrome (MDS) and leukemogenesis in human and murine model of leukemia. To date, no polymorphisms of PRDM16 gene in bovine had been reported. Herein, PCR-SSCP and DNA sequencing methods were employed to screen the genetic variation within PRDM16 gene in 1031 Chinese indigenous bovine. The results revealed two novel silent mutations: XM_001788152: m.1641T>C (547aa), 1881G>A (627aa). Hence, we described the PvuII and HaeIII forced PCR-RFLP methods for detecting these mutations, respectively. In the forced PCR-RFLP analysis with PvuII, the frequencies of bovine PRDM16-C allele varied from 0.044 to 0.506 in four Chinese native breeds. In the forced PCR-RFLP analysis with HaeIII, the frequencies of bovine PRDM16-G allele were 0.474, 0.494, 0.576 and 0.906 for Jiaxian (JX), Nanyang (NY), Qinchuan (QC) and Chinese Holstein (CH) population. Significant statistical differences between genotypic frequencies implied that both of the polymorphic loci were significantly associated with cattle breeds by the chi square test (chi2 = 190.058, P < 0.001 and chi2 = 118.239, P < 0.001 for PvuII; chi2 = 209.842, P < 0.001 and chi2 = 108.711, P < 0.001 for HaeIII). The associations of the PvuII and HaeIII forced PCR-RFLPs of bovine PRDM16 loci with growth traits were analyzed in Nanyang breed. The two SNPs were associated with body weight and average daily gain in Nanyang aged 12 months, individuals with genotype TT and AA showed significantly better body weight (P < 0.05) and average daily gain (P < 0.01) at 12 months, respectively.

[Novel 35-bp insertion in visfatin gene in Chinese cattle]

Visfatin is a protein that is preferentially produced in visceral adipose tissue. Both its tissue expression and secreted plasma levels increase in parallel with obesity. Therefore, the present study is focused on detecting insertion in bovine visfatin gene and analyzing its effect on growth traits in four Chinese cattle breeds (Nangyang, Qinchuan, Jiaxian, and Chinese Holstein) using PCR-SSCP, DNA sequencing and agarose electrophoresis methods. For the first time, a 35-bp insertion was described in the gene and two alleles were revealed: Wand I. The chi2-test analysis demonstrated that all breeds were in agreement with Hardy-Weinberg equilibrium (P > 0.05). The associations of the novel 35bp-insertion of visfatin gene with growth traits of Nanyang cattle at 6, 12, 18, and 24 months old were analyzed: 6-month-old cows with genotype WW had greater birth weight than cows with genotype II and WI (P < 0.01 or P < 0.05). These results suggest that the presence of 35bp-insertion in visfatin gene may influence the birth weight and bodyweight in 6-month-old cows.

A coding SNP of LHX4 gene is associated with body weight and body length in bovine

Heterozygous mutations in LHX4 are associated with combined pituitary hormone deficiency. In this study, the polymorphism of LHX4-HaeIII locus was revealed in 822 individuals from four Chinese cattle breeds. The PCR-RFLP analysis showed that there were three genotypes: GG, GA, AA. The frequencies of genotype GG ranged from 0.6620 to 0.9789 in analyzed populations. The genotypic frequencies of LHX4 locus in the four populations all agreed with Hardy-Weinberg equilibrium (P > 0.05). Distributions of genotypic frequencies of different breeds (QC, NY, JX, CH) at this locus were found to be significantly different based on a chi(2) test (P < 0.001). The genetic diversity analysis revealed the JX cattle possessed intermediate genetic diversity, and the other three Chinese cattle breeds belonged to poor genetic diversity. Correlation analysis with growth traits in the NY breed indicated that: the animals with genotype GA had greater body weight than those with genotype GG (P < 0.05); the animals with GA genotype owned significantly longer body length than the ones with GG genotype (P < 0.05) at 18 and 24 months.

aPCR-SSCP and DNA sequencing detecting two silent SNPs at KAP8.1 gene in the cashmere goat

Keratin-associated proteins 8.1 gene (KAP8.1) is a structural gene responsible for the cashmere. KAP8.1 protein contains high glycine and tyrosine, which concerns regulation and function of the matrix structure fiber. In this study, the polymorphism of KAP8.1 gene was detected by methods of aPCR-SSCP (asymmetric polymerase chain reaction single-strand conformation polymorphism) and DNA sequencing in 791 individuals from two breeds. The results showed that there were two mutations in this gene. The mutations were described as c.63 T>G and c.66 C>G, which would result in two synonymous mutations in KAP8.1 protein. The findings go against previous research, in which there was not polymorphism at KAP8.1 gene. The reasons might be that different cashmere breeds were detected in two studies. Further analysis of results leads us to believe that the polymorphism of KAP8.1 gene might be relevant to fiber diameter.

A PstI polymorphism at 3'UTR of goat POU1F1 gene and its effect on cashmere production

POU1F1 is a positive regulator for prolactin (PRL) whose metabolites may directly or indirectly affect some aspects of the hair growth cycle, therefore, POU1F1 gene is an important candidate gene for cashmere traits selection through marker-assisted selection (MAS). Hence, in this study, the PCR-RFLP method was applied to detect a T>C transition determining a PstI polymorphism at the 3'UTR of POU1F1 locus and evaluate its associations with cashmere traits in 847 Inner Mongolia White Cashmere goats. In the analyzed population, the allelic frequencies for the T and C alleles are 0.959 and 0.041, respectively and the genotypic frequencies are in Hardy-Weinberg equilibrium (P > 0.05). Moreover, significant statistical relationships between the PstI polymorphism of POU1F1 gene and goat cashmere yields were found (*P < 0.05). When compared with TC genotype, TT genotype was associated with superior cashmere yields in 2, 4, and 5 years old individuals, as well as with average cashmere yield. Hence, TT genotype is suggested to be a molecular marker for senior cashmere yield.

Analysis of caprine pituitary specific transcription factor-1 gene polymorphism in indigenous Chinese goats

Since mutations on POU1F1 gene possibly resulted in deficiency of GH, PRL, TSH and POU1F1, this study revealed the polymorphism of goat POU1F1-AluI locus and analyzed the distribution of alleles on 13 indigenous Chinese goat breeds. The PCR-RFLP analysis showed the predominance of TT genotype and the frequencies of allele T varied from 0.757 to 0.976 in the analyzed populations (SBWC, Bo, XH and HM). Further study, distributions of genotypic and allelic frequencies at this locus were found to be significantly different among populations based on a chi(2)-test (P < 0.001), suggesting that the breed factor significantly affected the molecular genetic character of POU1F1 gene. The genetic diversity analysis revealed that Chinese indigenous populations had a wide spectrum of genetic diversity in goat POU1F1-AluI locus. However, the ANOVA analysis revealed no significant differences for gene homozygosty, gene heterozygosty, effective allele numbers and PIC (polymorphism information content) among meat, dairy and cashmere utility types (P > 0.05), suggesting that goat utility types had no significant effect on the spectrum of genetic diversity.

Serotonin receptor 1B (HTR1B) genotype associated with milk production traits in cattle

Serotonin receptor 1B (HTR1B) is one of the 14 different identified serotonin receptors which are involved in the regulation of behaviors such as sleep, fear, aggression, mood, and feeding. The aims of this study were to characterize polymorphisms in the 5' coding and the 3' flanking regions of the bovine HTR1B gene among Chinese Holsteins and to identify the association of HTR1B polymorphisms with milk production performance. SSCP was used to examine the polymorphisms at four loci and the fragments with different SSCP patterns were sequenced. A total of three single nucleotide polymorphisms (SNPs) were detected, among which the 205G>T mutation was found to cause a predicted amino acid change: from Ala to Ser at position 69. The polymorphism of G205T was identified to be associated with milk yield trait. Furthermore, the H1-C genotype was found to be associated with a significant increase in milk yield of 489kg vs. the H1-A genotype (P<0.05).

Origin and phylogeographical structure of Chinese cattle

Complete mitochondrial D-loop sequences of 231 samples were used to explore the origin and genetic diversity of Chinese cattle. Phylogenetical analysis of these sequences revealed both Bos taurus and Bos indicus mitochondrial types in Chinese cattle. Four of the previously identified mitochondrial DNA lineages (T1-T4) were identified in the Bos taurus type, including lineage T1, which was found for the first time in Chinese cattle. Two lineages (I1 and I2) were identified in the Bos indicus type. Our results support the suggestion that the Yunnan-Guizhou Plateau is the domestication site of Chinese zebu. We also found evidence that Tibetan cattle originated from taurine and zebu cattle. The distribution pattern of Chinese cattle breeds was closely related to the geographical and climatic background. It was possible to divide Chinese cattle in this study into two major groups: northern and southern cattle.

Establishment of a human malignant T lymphoma cell line carrying retrovirus-like particles with RT activity

We have established an IL-2 independent malignant lymphoma line (CM-1) from peripheral T lymphocytes donated by a female patient with nervous system disease, the biological characteristics of CM-1 cells was studied in this paper. Another T lymphocytes, such as peripheral T lymphocytes donated by a male patient with multiple sclerosis, could be transformed into a malignant lymphoma line by using filtered supernatant of the CM-1 cultured medium, thus the CM-2 cell line was established. The CM-1 and CM-2 cells were transplanted by subcutaneous inoculation into nude mice, and could cause the occurrence of typical malignant lymphoma. The observation of electron micrographs suggested the existence of virions in the CM-1 and CM-2 cells, and these virions were similar to retrovirus in the ultra-structure characteristics. It was found that this virus possesses reverse transcriptase activity. Results obtained from serological assay, molecular hybridization and PCR excluded the existence of other human viruses, which were commonly used in our laboratory. The unknown virus possesses strong transformation activity, and probably is a new retrovirus. Meanwhile, the work on the clone and sequence analysis of this virus are being carried out.