Expression of antimicrobial peptide Cecropin P1 in Saccharomyces cerevisiae and its antibacterial and antiviral activity in vitro

BACKGROUND: Cecropin P1, acting as an antimicrobial, has a broad-spectrum antibacterial activity with some antiviral and antifungal properties. It is a promising natural alternative to antibiotics which is originally isolated from the pig intestinal parasitic nematode Ascaris suum. Many studies have shown that Cecropin P1 is helpful for the prevention or treatment of clinical diseases. Therefore, it is very necessary to establish a safe, nontoxic, and efficient expression method of Cecropin P1. RESULTS: The results indicated that the recombinant protein was about 5.5 kDa showed by Tricine­SDS­ PAGE and Western blot. And Cecropin P1 was efficiently secreted and expressed after 12 h of induction, with an increasing yield over the course of the induction. Its maximum concentration was 7.83 mg/L after concentration and purification. In addition, in vitro experiments demonstrated that Cecropin P1 not only exerted a strong inhibitory effect on Escherichia coli, Salmonella sp., Shigella sp., and Pasteurella sp., but also displayed an antiviral activity against PRRSV NADC30-Like strain. CONCLUSIONS: Collectively, the strategy of expressing Cecropin P1 in Saccharomyces cerevisiae is harmless, efficient, and safe for cells. In addition, the expressed Cecropin P1 has antiviral and antibacterial properties concurrently.

Adaptive Diversification Between Yellow Fever Virus West African and South American Lineages: A Genome-Wide Study.

Yellow fever virus (YFV) has emerged as the causative agent of a vector-borne disease with devastating mortality in the tropics of Africa and the Americas. YFV phylogenies indicate that the isolates collected from West Africa, East and Central Africa, and South America cluster into different lineages and the virus spread into the Americas from Africa. To determine the nature of genetic variation accompanying the intercontinental epidemic, we performed a genome-wide evolutionary study on the West African and South American lineages of YFV. Our results reveal that adaptive genetic diversification has occurred on viral nonstructural protein 5 (NS5), which is crucially required for viral genome replication, in the early epidemic phase of these currently circulating lineages. Furthermore, major amino acid changes relevant to the adaptive diversification generally cluster in different structural regions of NS5 in a lineage-specific manner. These results suggest that YFV has experienced adaptive diversification in the epidemic spread between the continents and shed insights into the genetic determinants of such diversification, which might be beneficial for understanding the emergence and re-emergence of yellow fever as an important global public health issue.

Development of a Rapid and Sensitive Method for Detection of African Swine Fever Virus Using Loop-Mediated Isothermal Amplification

ABSTRACT A loop-mediated isothermal amplification (LAMP) assay was developed for rapid, sensitive and specific detection of African swine fever virus (ASFV). A set of LAMP primers was designed based on the sequence of the ASFV gene K205R. Reaction temperature and time were optimized to 64 oC and 60 min, respectively. LAMP products were detected by agarose gel electrophoresis or visually with the addition of fluorescent dye. The detection limit of the LAMP assay was approximately 6 copies of the target gene per microliter, 100 times more sensitive than conventional PCR. LAMP is a simple and inexpensive molecular assay format for ASFV detection. To date, African swine fever has not been reported in China. LAMP can be used to monitor ASFV spread into China, thereby reducing the threat of ASF.

Effects of polysaccharide from Chuanminshen violaceum on immune response of newcastle disease vaccine in chicken

Background: Newcastle disease (ND), caused by avian paramyxovirus serotype 1 (APMV-1), also known as Newcastle disease virus (NDV), is regarded as one of the two most devastating diseases of poultry with the characteristics of serious disease and high flock mortality. It causes severe economic losses in domestic poultry, especially in chickens. At present, there were no effective drugs to treat this disease and the main method to control ND was vaccination. Moreover, new strains of virus resistant to chemotherapy continue to emerge, so does the need for a safe and effective vaccine. The immune adjuvant can make vaccine generate a strong immune response providing long-term protection against infection. With commonly usage of some immune adjuvants (e.g. mineral oil and aluminium hydroxide), many problems were occurred, such as side effects, strong local stimulation and carcinogenesis, together with complicated preparation, or failure to increase immunogenicity of weak antigen and so on. Botanical polysaccharides, as a new type of adjuvant or immunopotentiator, had become the hot research area because of their less side effects and no toxicity. The purpose of this research was to observe whether Chuanminshen violaceum polysaccharide (CVPS) possessed synergistical immunoenhancement, and offer the theoretical evidence for developing potential new-type adjuvant. Materials, Methods & Results: 200 three-yellow chickens at one day of age were randomly divided into four groups and reared in separated pens. On 7 days old, the average maternal serum hemaglutination inhibition (HI) antibody titer was less than 3 log2, all chickens of each group (the average body weight (BW) was 120 g) were vaccinated with ND live vaccine through nasal drip and eye-drop. At the same time, the chickens in three CVPS groups (high, medium and low doses of CVPS) were orally administered with 0.5 mL of CVPS at concentrations of 100 mg/kg BW, 50 mg/kg BW, 25 mg/kg BW respectively, once a day for fi ve successive day, in negative control group (NC), with 0.5 mL of physiological saline, once a day for fi ve successive day. On days 14, 21 and 28, the serum antibody titer, erythrocyte-C3b receptor rosette rate (E-C3bRR), erythrocyte-C3b immune complex rosette rate (E-ICRR), peripheral lymphocyte proliferation and peripheral CD4+/CD8+ ratio were measured. The results showed that the antibody titer, E-C3bRR, elimination rate of immune complex and peripheral lymphocyte proliferation in three CVPS groups and peripheral CD4+/CD8+ ratio in medium dosage of CVPS group were significantly higher (P < 0.05) than those in control group throughout the process of whole experiment almost. Discussion: The CVPS not only improved the E-C3bRR and accelerated the elimination rate of CIC, but also induced higher antibody titer, peripheral lymphocyte proliferation and peripheral CD4+ /CD8+ ratio in chickens vaccinated against ND live vaccine. This indicated that CVPS possessed immune-enhancement efficacy of ND live vaccine and might be expected as a candidate of new-type adjuvant.

Effects of polysaccharide from Chuanminshen violaceum on immune response of Newcastle disease vaccine in chicken / Effects of polysaccharide from Chuanminshen violaceum on immune response of Newcastle disease vaccine in chicken

Background: Newcastle disease (ND), caused by avian paramyxovirus serotype 1 (APMV-1), also known as Newcastle disease virus (NDV), is regarded as one of the two most devastating diseases of poultry with the characteristics of serious disease and high flock mortality. It causes severe economic losses in domestic poultry, especially in chickens. At present, there were no effective drugs to treat this disease and the main method to control ND was vaccination. Moreover, new strains of virus resistant to chemotherapy continue to emerge, so does the need for a safe and effective vaccine. The immune adjuvant can make vaccine generate a strong immune response providing long-term protection against infection. With commonly usage of some immune adjuvants (e.g. mineral oil and aluminium hydroxide), many problems were occurred, such as side effects, strong local stimulation and carcinogenesis, together with complicated preparation, or failure to increase immunogenicity of weak antigen and so on. Botanical polysaccharides, as a new type of adjuvant or immunopotentiator, had become the hot research area because of their less side effects and no toxicity. The purpose of this research was to observe whether Chuanminshen violaceum polysaccharide (CVPS) possessed synergistical immunoenhancement, and offer the theoretical evidence for developing potential new-type adjuvant. Materials, Methods &a

Background: Newcastle disease (ND), caused by avian paramyxovirus serotype 1 (APMV-1), also known as Newcastle disease virus (NDV), is regarded as one of the two most devastating diseases of poultry with the characteristics of serious disease and high flock mortality. It causes severe economic losses in domestic poultry, especially in chickens. At present, there were no effective drugs to treat this disease and the main method to control ND was vaccination. Moreover, new strains of virus resistant to chemotherapy continue to emerge, so does the need for a safe and effective vaccine. The immune adjuvant can make vaccine generate a strong immune response providing long-term protection against infection. With commonly usage of some immune adjuvants (e.g. mineral oil and aluminium hydroxide), many problems were occurred, such as side effects, strong local stimulation and carcinogenesis, together with complicated preparation, or failure to increase immunogenicity of weak antigen and so on. Botanical polysaccharides, as a new type of adjuvant or immunopotentiator, had become the hot research area because of their less side effects and no toxicity. The purpose of this research was to observe whether Chuanminshen violaceum polysaccharide (CVPS) possessed synergistical immunoenhancement, and offer the theoretical evidence for developing potential new-type adjuvant. Materials, Methods &a

Effects of polysaccharide from Chuanminshen violaceum on immune response of Newcastle disease vaccine in chicken / Effects of polysaccharide from Chuanminshen violaceum on immune response of Newcastle disease vaccine in chicken

Background: Newcastle disease (ND), caused by avian paramyxovirus serotype 1 (APMV-1), also known as Newcastle disease virus (NDV), is regarded as one of the two most devastating diseases of poultry with the characteristics of serious disease and high flock mortality. It causes severe economic losses in domestic poultry, especially in chickens. At present, there were no effective drugs to treat this disease and the main method to control ND was vaccination. Moreover, new strains of virus resistant to chemotherapy continue to emerge, so does the need for a safe and effective vaccine. The immune adjuvant can make vaccine generate a strong immune response providing long-term protection against infection. With commonly usage of some immune adjuvants (e.g. mineral oil and aluminium hydroxide), many problems were occurred, such as side effects, strong local stimulation and carcinogenesis, together with complicated preparation, or failure to increase immunogenicity of weak antigen and so on. Botanical polysaccharides, as a new type of adjuvant or immunopotentiator, had become the hot research area because of their less side effects and no toxicity. The purpose of this research was to observe whether Chuanminshen violaceum polysaccharide (CVPS) possessed synergistical immunoenhancement, and offer the theoretical evidence for developing potential new-type adjuvant. Materials, Methods &a

Background: Newcastle disease (ND), caused by avian paramyxovirus serotype 1 (APMV-1), also known as Newcastle disease virus (NDV), is regarded as one of the two most devastating diseases of poultry with the characteristics of serious disease and high flock mortality. It causes severe economic losses in domestic poultry, especially in chickens. At present, there were no effective drugs to treat this disease and the main method to control ND was vaccination. Moreover, new strains of virus resistant to chemotherapy continue to emerge, so does the need for a safe and effective vaccine. The immune adjuvant can make vaccine generate a strong immune response providing long-term protection against infection. With commonly usage of some immune adjuvants (e.g. mineral oil and aluminium hydroxide), many problems were occurred, such as side effects, strong local stimulation and carcinogenesis, together with complicated preparation, or failure to increase immunogenicity of weak antigen and so on. Botanical polysaccharides, as a new type of adjuvant or immunopotentiator, had become the hot research area because of their less side effects and no toxicity. The purpose of this research was to observe whether Chuanminshen violaceum polysaccharide (CVPS) possessed synergistical immunoenhancement, and offer the theoretical evidence for developing potential new-type adjuvant. Materials, Methods &a