Caspase Work Model During Pathogen Infection

Caspases are an evolutionarily conserved family of aspartate-specific cystein-dependent proteases with essential functions in apoptosis and normally exist in cells as inactive proenzymes. In addition to the inflammatory caspases, the initiator and effector caspases have been shown to have an important role in regulating the immune response, but are involved in different ways. We give a brief introduction on the benefit of apoptosis on the clearance of invasive pathogens, and the caspase functions involved in the immune response. Then we construct a working model of caspases during pathogen invasion. A detailed description of the three modes is given in the discussion. These three modes are regulated by different inhibitors, and there may be a novel way to treat intracellular pathogen and autoimmune diseases based on the specific inhibitors.

Role of the Arabidopsis thafiana NAC transcription factors ANAC019 and ANAC055 in regulating jasmonic acid-signaled defense responses

Jasmonic acid （JA） is an important phytohormone that regulates plant defense responses against herbivore attack, pathogen infection and mechanical wounding. In this report, we provided biochemical and genetic evidence to show that the Arabidopsis thaliana NAC family proteins ANAC019 and ANAC055 might function as transcription activators to regulate JA-induced expression of defense genes. The role of the two NAC genes in JA signaling was examined with the anacO19 anac055 double mutant and with transgenic plants overexpressing ANACO19 or ANAC055. The anacO19 anac055 double mutant plants showed attenuated JA-induced VEGETATIVE STORAGE PROTEIN1 （VSP1） and LIPOXYGENASE2 （LOX2） expression, whereas transgenic plants overexpressing the two NAC genes showed enhanced JA-induced VSP1 and LOX2 expression. That the JA-induced expression of the two NAC genes depends on the function of COIl and AtMYC2, together with the finding that overexpression of ANACO19 partially rescued the JA-related phenotype of the atmyc2-2 mutant, has led us to a hypothesis that the two NAC proteins act downstream of AtMYC2 to regulate JA-signaled defense responses. Further evidence to substantiate this idea comes from the observation that the response of the anacO19 anac055 double mutant to a necrotrophic fungus showed high similarity to that of the atmyc2-2 mutant.

Screening of stable internal reference genes by quantitative real-time PCR in humpback grouper Cromileptes altivelis

Humpback grouper Cromileptes altivelis is one commercial fish with considerable economic value.To determine the expression stabilities of six commonly used internal reference genes in C.altivelis challenged by Vibrio harveyi and viral nervous necrosis virus(VNNV)through quantitative real-time PCR(qRT-PCR),the expression levels of selected genes in five immune organs stimulated with pathogenic infection were carefully evaluated using algorithms of geNorm,NormFinder,and BestKeeper.The results show that the expre ssion stabilities of the six candidate inte rnal reference genes were diffe re nt.Under no rmal physiological conditions,RPL13 were identified as the most stably expressed genes among five different immune organs(liver,spleen,kidney,intestine,and gill).After V.harveyi stimulation,RPL13,RPL13,EF1 A,RPL13,and EF1 A were identified by geNorm,NormFinder,and BestKeeper as the most stable genes in liver,spleen,kidney,intestine,and gill,respectively.Combining these three algorithms suggested that under stimulation of VNNV,RPL13,EF1 A,Actin,RPL13,and Actin were as the most stable genes in liver,spleen,kidney,intestine,and gill,respectively.These results suggest that specific experiment conditions and tissue types shall be considered when selecting the reference genes in qRT-PCR analysis.This study provided a solid foundation for future studies on gene expression of C.altivelis under different conditions.

Molecular cloning and functional identification of an apple flagellin receptor MdFLS2 gene

The leucine-rich repeat receptor kinase flagellin-sensing 2 gene(MdFLS2; Gene ID: MDP0000254112) was cloned from Royal Gala apple(Malus×domestica Borkh.). This gene contained a complete open reading frame of 3 474 bp that encoded 1 158 amino acids. The phylogenetic tree indicated that Prunus persica FLS2 exhibited the highest sequence similarity to MdFLS2. The PlantCare database suggests that the promoter sequence of MdFLS2 contains several typical cis-acting elements, including ethylene-, gibberellin-, salicylic acid-, and drought-responsive elements. Quantitative real-time PCR analysis showed that MdFLS2 was widely expressed in the different tissues of the apple and most highly expressed in the leaves. Furthermore, MdFLS2 was significantly induced by the flagellin elicitor peptide flg22. Treatment of the apple seedling leaves with flg22 resulted in an increase in leaf callose levels with increased treatment duration. An increase in the production of Oalong with the expression of disease-related genes was also observed. An oxidative burst was detected in the treated seedlings, but not in the control seedlings, indicating that flg22 had stimulated the expression of the MdFLS2 gene and its downstream target genes. Furthermore, the ectopic expression of MdFLS2 complemented the function of the Arabidopsis fls2 mutant and conferred enhanced flg22 tolerance to the transgenic Arabidopsis, suggesting that MdFLS2 acts as a positive regulator in the response to pathogens in apple.

Identification and characterization of the GH3 gene family in maize

The phytohormone auxin plays a central role in coordinating plant growth and development.GH3 is one of the three gene families that respond rapidly during auxin stimulation.Here,we report the identification and characterization of the GH3 gene family in maize.A total of 12 GH3 genes were identified,which are not evenly distributed over the 10 maize chromosomes.Maize GH3 protein sequences share a conserved domain which occupies nearly the entire protein.Diversified c/＇s-elements were found in promoters of maize GH3 genes.In this study,the 12 maize GH3 proteins were primarily classified into two phylogenetic groups,similar to the 13 rice GH3 proteins,while 9 of the 19 Arabidopsis GH3 proteins were observed in the third phylogenetic group.Microarray analysis showed that expression of maize GH3 genes is temporally and spatially modulated.Additionally,maize GH3 genes displayed variable changes at transcript level upon pathogen infection.Results presented here provide insight into the diversification and evolution of GH3 proteins,and lay a foundation for the functional characterization of these GH3 genes in future,especially for elucidating the mechanisms of GH3-mediated pathogenesis.

Type I strain of Toxoplasma gondii from chicken induced different immune responses with that from human,cat and swine in chicken

In this study,four strains of Toxoplasma gondii with the same genetic type（Type I） originated from chicken,human,cat and swine were used to compare the immune responses in resistant chicken host to investigate the relationships between the parasite origins and the pathogenicity in certain host.A total of 300,10-day-old chickens were allocated randomly into five groups which named JS（from chicken）,CAT（from cat）,CN（from swine）,RH（from human） and a negative control group（—Ve） with 60 birds in each group.Tachyzoites of four different T.gondii strains（JS,CAT,CN and RH） were inoculated intraperitoneally with the dose of 1×10~7 in the four designed groups,respectively.The negative control（-Ve） group was mockly inoculated with phosphate-buffered saline（PBS） alone.Blood and spleen samples were obtained on the day of inoculation（day 0） and at days 4,11,25,39 and 53 post-infection to screen the immunopathological changes.The results demonstrated some different immune characters of T.gondii infected chickens with that of mice or swine previous reported.These differences included up-regulation of major histocompatibility complex class Ⅱ（MHC Ⅱ） molecules in the early stage of infection,early peak expressions of interleukin（IL）-12（IL-12） and-10（IL-10） and long keep of IL-17.These might partially contribute to the resistance of chicken to T.gondii infection.Comparisons to chickens infected with strains from human,cat and swine,chickens infected with strain from chicken showed significant high levels of CD4~＋ and CD8~＋ T cells,interferon gamma（IFN-γ）,IL-12 and IL-10.It suggested that the strain from chicken had different ability to stimulate cellular immunity in chicken.

Immunologically effective biomaterials-enhanced vaccines against infection of pathogenic microorganisms

Infectious diseases are severe public health events that threaten global health.Prophylactic vaccines have been considered as the most effective strategy to train the immune system to recognize and clear pathogenic infections.However,the existing vaccines against infectious diseases have several limitations,such as difficulties in mass manufacturing and storage,weak immunogenicity,and low efficiency of available adjuvants.Biomaterials,especially functional polymers,are expected to break through these bottlenecks based on the advantages of biocompatibility,degradability,controlled synthesis,easy modification,precise targeting,and immune modulation,which are excellent carriers and adjuvants of vaccines.This review mainly summarizes the application of immunologically effective polymers-enhanced vaccines against viruses-and bacteria-related infectious diseases and predicted their potential improvements.

A Review on Resistance to Biotic Stress in Leaf-Colored Plant

As sessile organisms, plants have to be subjected to insect attack. Over the long course of evolution, plants have produced many mechanisms to resist this biotic stress such as pigment accumulation. Pigment levels determined depth and distribution of leaf color, thereby indirectly or directly affecting the behavior of insect attack. Therefore, understanding the mechanism of mutual recognition between leaf color and insect will provide important theoretical insight for the cultivation and improvement of new cultivars. This paper outlines leaf-color formation and the effect of pigment on the behavior of insect attack, and explores the challenge of research in the interaction between leaf color and insect, as soon as the potential direction for future development. This will give a broad background for improvements of colored plants with resistance to insect attack.

Skin neuropathy and immunomodulation in diseases

Skin is a vital barrier tissue of the body.Immune responses in the skin must be precisely controlled,which would otherwise cause severe disease conditions such as psoriasis,atopic dermatitis,or pathogenic infection.Research evidence has increasingly demonstrated the essential roles of neural innervations,i.e.,sensory and sympathetic signals,in modulating skin immunity.Notably,neuropathic changes of such neural structures have been observed in skin disease conditions,implicating their direct involvement in various pathological processes.An in-depth understanding of the mechanism underlying skin neuropathy and its immunomodulatory effects could help reveal novel entry points for therapeutic interventions.Here,we summarize the neuroimmune interactions between neuropathic events and skin immunity,highlighting the current knowledge and future perspectives of this emerging research frontier.

Porcine circovirus type 2(PCV2)and Campylobacter infection induce diarrhea in piglets:Microbial dysbiosis and intestinal disorder

Diarrhea is considered to be associated with microbial dysbiosis caused by infection of pathogens but poorly understood.We herein characterized the colonic microbiota of diarrheal early-weaning piglets infected with porcine circovirus type 2(PCV2)and Campylobacter.Campylobacter infection significantly decreased species richness and Shannon diversity index of colonic microbiota together with a significant increase in the proportion of Campylobacter and Enterobacteriaceae,whereas no significant difference on the above indexes was observed in piglets infected with PCV2 compared with healthy piglets,PCV2 and Campylobacter infection could disturb the homeostasis of colonic microbiota through deterioration of ecological network within microbial community,and specially Campylobacter performed as a module hub in ecological networks.The microbial dysbiosis caused metabolic dysfunction and led to a remarkable reduction in production of short chain fatty acids,following by a higher pH level in colon cavity.Campylobacter infection disturbed the function of colonic tract barrier observed in terms of significant lower relative expression of claudin-1,occluding,and zonula occludens protein-1 genes,and PCV2 infection induced intestinal inflammation together with a higher permeability of colon.Generally,these results suggested that PCV2 and Campylobacter infection could induce microbial dysbiosis and metabolic dysfunction,and cause intestinal disorder,all of which finally were associated to contribute to the diarrhea of early-weaning piglets.

T lymphocytes in the intestinal mucosa: defense and tolerance

Although lymphocytes are known to circulate throughout lymphoid tissues and blood,they also establish residency in nonlymphoid organs,most prominently in barrier tissues,such as the intestines.The adaptation of T lymphocytes to intestinal environments requires constant discrimination between natural stimulation from commensal flora and food and pathogens that need to be cleared.Genetic variations that cause a defective defense or a break in tolerance along with environmental cues,such as infection or imbalances in the gut microbiota known as dysbiosis,can trigger several immune disorders via the activation of T lymphocytes in the intestines.Elucidation of the immune mechanisms that distinguish between commensal flora and pathogenic organisms may reveal therapeutic targets for the prevention or modulation of inflammatory diseases and boost the efficacy of cancer immunotherapy.In this review,we discuss the development and adaptation of T lymphocytes in the intestine,how these cells protect the host against pathogenic infections while tolerating food antigens and commensal microbiota,and the potential implications of targeting these cells for disease management and therapeutics.

A quantitative evaluation of the biochar’s influence on plant disease suppress:a global meta-analysis

Numerous studies have demonstrated that soil applications of biochar contribute to plant disease suppression and growth promotion.Here,we quantitatively evaluated the performance of biochars on plant disease suppression and production using meta-analysis of literature data.The results indicated that biochar amendment dramatically reduced disease severity(DS)by 47.46%while increasing plant biomass by 44.05%.The highest disease suppression was achieved with soil application of straw-derived biochar compared to biochar from other feedstocks,while no significant increase in yield was found with straw-derived biochar.Biochars pyrolyzed at medium temperatures(350-600℃)facilitate both disease controlling and growth promotion.Soil application of biochars between 3 and 5%significantly decreased plant DS by 59.11%,and inverted U-shaped biochar dose/DS suppression curve and biochar dose/growth curve were observed.In cash crop fields,the DS of plants amended with biochar was reduced over 50%,which was significantly higher than that of grain crops and perennial trees.Furthermore,biochar performance on plant disease suppression was higher for airborne pathogens than for soilborne pathogens,possibly due to the systemic activation of plant defences by biochar amendment.Additionally,a reduction of DS by biochar was observed on plants grown in agricultural soils.Our work contributes to the standardization of biochar production and provides a reference for improving the function of biochar in disease control.

Characterization and complete genome sequence of vB_EcoP-Bp4,a novel polyvalent N4-like bacteriophage that infects chicken pathogenic Escherichia coli

Pathogenic Escherichia coli cause chicken colibacillosis, which is economically devastating to the poultry in- dustry worldwide （Bagheri et al., 2014）. Owing to in- creasing antibiotic resistance, phage therapy reagents have been developed to treat bacterial infections （Xu et al., 2015）.

Coronavirus: epidemiology, genome replication and the interactions with their hosts

This special issue of the journal is dedicated to the recent progress on coronaviruses and covers the topics of viral epidemiology,virus replication and the interactions between the coronaviruses and their hosts.Members of the family Coronaviridae infect a wide range of vertebrates and humans.