Bacillus amyloliquefaciens LM-1 Affects Multiple Cell Biological Processes in Magnaporthe oryzae to Suppress Rice Blast.

Magnaporthe oryzae, one of the most destructive rice pathogens, causes significant losses during the rice harvest every year. Bacillus amyloliquefaciens has been explored in many crops as a potential biocontrol agent. However, the mechanisms of B. amyloliquefaciens controled rice blast are not fully understood. Here, a biocontrol strain LM-1, isolated from a contaminated medium, was identified as B. amyloliquefaciens using morphological observation, physiological and biochemical tests, and 16S rDNA sequencing. LM-1 inhibited the growth and pathogenicity of M. oryzae and Bipolaris oryzae (Breda de Haan) Shoem. The mycelia of M. oryzae co-cultured with LM-1 were enlarged and broken by fluorescence microscopy using calcofluor white. LM-1 inhibited the mycelia of M. oryzae from producing conidia. Genes itu, srf, and fenB were detected in LM-1. Furthermore, the supernatant of LM-1 interfered with the appressorium formation of M. oryzae, blocked conidial cell death, and reduced autophagy degradation but did not affect the normal germination of rice seeds and seeding growth. Additionally, we observed hypersensitivity reactions, reactive oxygen species, and iron accumulation reduction in rice cells inoculated with supernatant. Our study reveals that LM-1 has a control effect on rice blast and affects cell wall integrity, sporulation, appressorium formation, cell death, and autophagy.

Molecular characterization and complement activating functional analysis of a new collectin(TfCol-11) from Trachidermus fasciatus.

The complement system is a crucial component of the innate immune system that links innate and adaptive immunity. CL-11, a protein similar to Mannose-binding lectin (MBL), plays significant role in the innate immune system in mammals and fish, serving as an initiator of the lectin pathway of complement activation. In this study, a CL-11 homolog (TfCol-11) was identified in roughskin sculpin (Trachidermus fasciatus), and its expression and role in immune responses were characterized. The open reading frame of TfCol-11 is 795 bp long, encoding a 264 amino acid polypeptide. The deduced amino acid sequence of this protein is highly homologous to sequences in other teleosts, and is similar to vertebrate CL-11, containing a canonical collagen-like region, a carbohydrate recognition domain, and a neck region. Recombinant TfCol-11 purified from Escherichia coli(E.coli) was able to bind to different microbes in a Ca2+-independent manner. Meanwhile, a 993 bp-long of partial MASP cDNA with a 96 bp 5' untranslated region (UTR) was also cloned from roughskin sculpin, containing 299 amino acids and consisting of three domains (CUB-EGF-CUB). qRT-PCR indicated that TfCol-11 and MASP mRNAs were predominately co-expressed in the liver. The temporal expression of TfCol-11 and MASP were both drastically up-regulated in the liver, skin, and blood by LPS challenge. Recombinant TfCol-11 purified from E.coli BL21(DE3) was able to agglutinate some bacteria in a Ca2+-dependent manner. In addition, an in vitro pull-down experiment demonstrated that TfCol-11 was able to bind to MASP, and in vivo experiments showed that TfCol-11 was associated with increased membrane attack complex (MAC) levels. It is therefore possible that TfCol-11 may plays a role in activating the complement system and in the defense against invading microorganisms in roughskin sculpin.

Polyvalent protective immunogens identified from outer membrane proteins of Vibrio parahaemolyticus and their induced innate immune response.

Vaccines are the most economic, efficient and environment-friendly agents in protecting host against bacterial infection. In aquaculture, polyvalent vaccines targeting more than one bacterial specie are highly demanded due to the presence of various types of bacterial pathogens in farming environment. Here eighteen genes encoding outer membrane proteins of Vibrio parahaemolyticus were cloned and expressed. The expressed recombinant proteins were used for antiserum preparation. Passive and active immune protection of the antiserum and recombinant proteins was investigated in the zebrafish model. Two recombinant proteins, VP1667 and VP2369, showed effective immune protection against at least two genera of bacteria, Vibrio (V. parahaemolyticus and V. alginolyticus), Pseudomonas (P. fluorescens) or/and Aeromonas (A. hydrophila), and thereby are potential polyvalent vaccine candidates to defend against bacterial infection in fish farming. Furthermore, the mechanisms for the two polyvalent vaccines in triggering immune response were explored. Antiserum to VP1667 or VP2369 was not cross-reacted with P. fluorescens and A. hydrophila, whereas both recombinant proteins induced significant innate immune response. Comparatively, VP1667 stimulates stronger lymphokine and monokine, and VP2369 induces stronger humoral immune response, while both produce similar NF-κB, COX-2, TLR-1 and TLR-3 expression. Our results identify two polyvalent vaccines and demonstrate characteristics features of their cross-protection at the content of the innate immune response.

Updated incidence rates and risk factors of esophageal cancer in Nan'ao Island, a coastal high-risk area in southern China.

Esophageal cancer (EC) is one of the most common cancers in China. The purpose of this study was to investigate the updated incidence rates and risk factors of EC in Nan'ao Island, where the EC incidence rate was chronically the highest in southern China. To calculate the annual incidence rate, data on 338 EC cases from Nan'ao Cancer Registry system diagnosed during 2005-2011 were collected. A case-control study was conducted to explore the EC risk factors. One hundred twenty-five alive EC patients diagnosed during 2005-2011 and 250 controls were enrolled into the case-control study. A pre-test questionnaire on demography, dietary factors, drinking water treatment, and behavioral factors was applied to collect information of all participants. The average EC incidence rates during 2005-2011 were 66.09/105, 94.62/105, 36.83/105 for both genders, males and females, respectively, in Nan'ao Island. The EC incidence rate in males was 2.40- to 4.55-fold higher than that in females in the period from 2006 to 2011 (P < 0.05). Considering the onset age, males tend to be much younger than females and reached peak incidence rate at a younger age (P < 0.05). Drinking water treatment by filter (odds ratio [OR] = 0.28, 95% confidence interval [95% CI] = 0.13-0.58) and fruit consumption (OR = 0.55, 95% CI = 0.32-0.94) reduced the risk for EC. On the contrary, the pickled vegetables consumption (OR = 2.64, 95% CI = 1.46-4.76) and liquor drinking (OR = 2.32, 95% CI = 1.21-4.44) increased the risk for EC. These results may be of importance for future research on EC etiology and prevention strategies.