Onosma glomeratum Y. L. Liu polysaccharide alleviates LPS-induced pulmonary inflammation via NF-κB signal pathway.

As a traditional Chinese medicinal and edible homologous plant, Onosma glomeratum Y. L. Liu has been used for treating lung diseases in Tibet. In this study, a pectin polysaccharide, OGY-LLPA, with a molecular weight of 62,184 Da, was isolated and characterized by GC-MS and NMR analysis. It mainly consists of galacturonic acid (GalA), galactose (Gal), rhamnose (Rha), and arabinose (Ara), with a linear main chain of galacturonic acid (homogalacturonan, HG) inserted by part of rhamnose galacturonic acid (rhamnogalacturonan, RG), attaching with arabinogalactan (AG) branches at RG-I. Both in the LPS-induced A549 cell model and LPS-induced pneumonia mouse model, OGY-LLPA demonstrated strong anti-inflammatory effects, even comparable to DEX, indicating its potential as an anti-pneumonia candidate agent. Moreover, low-dose OGY-LLPA alleviated LPS-induced pulmonary inflammation by inhibiting the NF-κB signaling pathway. Overall, these findings could not only contribute to the utilization of Onosma glomeratum Y. L. Liu., but also provides a theoretical basis for the treatment of inflammation-related diseases.

Starvation induces hepatopancreas atrophy in Chinese mitten crab (Eriocheir sinensis) by inhibiting angiogenesis.

BACKGROUND: The hepatopancreas of crustaceans serves as a significant organ for both the synthesis and secretion of digestive enzymes, as well as energy storage. In the event of food shortage, the hepatopancreas can provide energy for survival. To investigate the potential regulatory mechanisms of the hepatopancreas in response to starvation in Eriocheir Sinensis, transcriptome analysis, histological study and qRT-PCR were performed. RESULTS: The results showed that starvation caused a decrease in the hepatopancreas index of E. sinensis, which had certain effects on the tissue structure, metabolism and angiogenesis in the hepatopancreas. In addition, WGCNA and linear regression analysis showed that the genes significantly related to the hepatopancreas index were mainly enriched in the angiogenesis pathway, in which AKT signaling played an important role. Starvation may inhibit AKT signaling pathway by reducing the expression of TGFBI, HSP27, HHEX, and EsPVF1, thereby hindering angiogenesis, promoting apoptosis, and leading to hepatopancreas atrophy. CONCLUSION: These results indicate that AKT plays an important role in the angiogenesis pathway and apoptosis of the starvation induced hepatopancreas index reduction, which is beneficial to further understand the effect of starvation stress on hepatopancreas of Chinese mitten crab.

Association between Phenotypes of Antimicrobial Resistance, ESBL Resistance Genes, and Virulence Genes of Salmonella Isolated from Chickens in Sichuan, China.

The aim of this study was to explore the association between antimicrobial resistance, ESBL genes, and virulence genes of Salmonella isolates. From 2019 to 2021, a total of 117 Salmonella isolates were obtained from symptomatic chickens in Sichuan Province, China. The strains were tested for antimicrobial resistance and the presence of ESBL according to the Clinical and Laboratory Standards Institute (CLSI) instructions. The presence of ESBL genes and genes for virulence was determined using Polymerase Chain Reaction (PCR). In addition, Multilocus Sequence Typing (MLST) was applied to confirm the molecular genotyping. Moreover, the mechanism of ESBL and virulence gene transfer and the relationships between the resistance phenotype, ESBL genes, and virulence genes were explored. The isolates exhibited different frequencies of resistance to antibiotics (resistance rates ranged from 21.37% to 97.44%), whereas 68.38% and 41.03% of isolates were multi-drug resistance (MDR) and ESBL-producers, respectively. In the PCR analysis, blaCTX-M was the most prevalent ESBL genotype (73.42%, 58/79), and blaCTX-M-55 showed the most significant effect on the resistance to cephalosporins as tested by logistic regression analysis. Isolates showed a high carriage rate of invA, avrA, sopB, sopE, ssaQ, spvR, spvB, spvC, stn, and bcfC (ranged from 51.28% to 100%). MLST analysis revealed that the 117 isolates were divided into 11 types, mainly ST92, ST11, and ST3717. Of 48 ESBL-producers, 21 transconjugants were successfully obtained by conjugation. Furthermore, ESBL and spv virulence genes were obtained simultaneously in 15 transconjugants. These results highlighted that Salmonella isolates were common carriers of ESBLs and multiple virulence genes. Horizontal transfer played a key role in disseminating antimicrobial resistance and pathogenesis. Therefore, it is necessary to continuously monitor the use of antimicrobials and the prevalence of AMR and virulence in Salmonella from food animals and to improve the antibiotic stewardship for salmonellosis.

Cinnamaldehyde Restores Ceftriaxone Susceptibility against Multidrug-Resistant Salmonella.

In recent years, infections caused by multidrug-resistant (MDR) bacteria have greatly threatened human health and imposed a burden on global public health. To overcome this crisis, there is an urgent need to seek effective alternatives to single antibiotic therapy to circumvent drug resistance and prevent MDR bacteria. According to previous reports, cinnamaldehyde exerts antibacterial activity against drug-resistant Salmonella spp. This study was conducted to investigate whether cinnamaldehyde has a synergistic effect on antibiotics when used in combination, we found that cinnamaldehyde enhanced the antibacterial activity of ceftriaxone sodium against MDR Salmonella in vitro by significantly reduced the expression of extended-spectrum beta-lactamase, inhibiting the development of drug resistance under ceftriaxone selective pressure in vitro, damaging the cell membrane, and affecting its basic metabolism. In addition, it restored the activity of ceftriaxone sodium against MDR Salmonella in vivo and inhibited peritonitis caused by ceftriaxone resistant strain of Salmonella in mice. Collectively, these results revealed that cinnamaldehyde can be used as a novel ceftriaxone adjuvant to prevent and treat infections caused by MDR Salmonella, mitigating the possibility of producing further mutant strains.

Structural and pharmacological diversity of 1,4-naphthoquinone glycosides in recent 20 years.

1,4-naphthoquinones are the most widespread naphthoquinone compounds. Recently, many 1,4-naphthoquinone glycosides with different structural features have been obtained from both nature and synthesis, which has led to an increasing variety of naphthoquinone glycosides. In this paper, the structure variety and biological activity in recent 20 years are reviewed, and classified them according to the source and structure characteristics. Meanwhile the synthetic methods of O-, S-, C- and N-naphthoquinone glycosides and their structure activity relationships are also described. It was referred that the presence of polar groups of C2 and C5 and non-polar groups attached to C3 on the naphthoquinone ring are beneficial for their biological activities. It will provide more comprehensive literature resources for the future research of 1, 4-naphthoquinone glycosides and lay a theoretical foundation.

Synthesis of structurally diverse derivatives of aconitine-type diterpenoid alkaloids and their anti-proliferative effects on canine breast cancer cells.

As one of the most common malignancies in female dogs, no drugs have been developed specifically for the treatment of canine mammary carcinoma. In our previous study, a series of diterpenoid alkaloids derivatives were synthesized and exhibited good anti-proliferative activity in vitro against both normal and adriamycin-resistant human breast cancer cells lines. In this study, a series of structurally diverse aconitine-type alkaloids derivatives were also synthesized basing on the minimal modification principle, by modifying on A-ring, C-ring, D-ring, N-atom or salt formation on aconitine skeleton. Their anti-proliferative effects and mechanism on canine mammary cancer cells were investigated, exhibiting the importance of the substitution at A ring, the long chain ester at the C8, the hydroxyl group at the C13, the phenyl ring at the C14 and the N-ethyl group, while the methoxy group at the C1 and C16 showed little effect on the activity. The results of the proliferation, apoptosis and ultrastructure tests of the treated canine mammary carcinoma cells referred that the representative compound, aconitine linoleate (25) could block the cell cycle of canine mammary carcinoma cells in the G0/G1 phase, and exhibit the anti-proliferative effect by inducing apoptosis.

Characteristics of pathology and transcriptome profiling reveal features of immune response of acutely infected and asymptomatic infected of carp edema virus in Koi.

Koi sleepy disease (KSD) is a high mortality and infection viral disease caused by carp edema virus (CEV), which was a serious threat to aquaculture of common carp and export trade of Koi worldwide. Asymptomatic infection is an important cause of the difficulty in preventing KSD and its worldwide spread, because asymptomatic infection can be activated under appropriate condition. However, the understanding of the molecular correlates of these infections is still unknown. The purpose of this study was to compare the pathology change, enzyme activity, immunoglobulin activity, host and viral gene expression differences in acutely infected and cohabiting asymptomatic Koi infected with CEV. Healthy Koi were used as a control. The gross pathology, histopathology and ultrastructural pathology showed the difference and characteristics damage to the tissues of Koi under different infection conditions. Periodic Acid-Schiff stain (PAS), enzyme activity and immunoglobulin activity revealed changes in the immune response of gill tissue between acutely infected, asymptomatic infected and healthy Koi. A total of 111 and 2484 upregulated genes and 257 and 4940 downregulated genes were founded in healthy Koi vs asymptomatic infected Koi and healthy Koi vs acutely infected Koi, respectively. Additionally, 878 upregulated genes and 1089 downregulated genes were identified in asymptomatic vs. acutely infected Koi. Immune gene categories and their corresponding genes in different comparison groups were revealed. A total of 3, 59 and 28 immune-related genes were identified in the group of healthy Koi vs asymptomatic infected Koi, healthy Koi vs acutely infected Koi and asymptomatic infected Koi vs acutely infected Koi, respectively. Nineteen immune-related genes have the same expression manner both in healthy Koi vs acutely infected Koi and asymptomatic Koi vs acutely infected Koi, while 9 immune-related genes were differentially expressed only in asymptomatic Koi vs acutely infected Koi, which may play a role in viral reactivation. In addition, 8 differentially expressed genes (DEGs) were validated by quantitative reverse transcription PCR (RT-qPCR), and the results were consistent with the RNA-Seq results. In conclusion, the data obtained in this study provide new evidence for further elucidating CEV-host interactions and the CEV infection mechanism and will facilitate the implementation of integrated strategies for controlling CEV infection and spread.

Resveratrol alleviated neuroinflammation induced by pseudorabies virus infection through regulating microglial M1/M2 polarization.

BACKGROUND: Pseudorabies virus (PRV) infections in susceptible non-porcine species trigger uncontrolled inflammations and eventually fatal encephalitis. Resveratrol (Res) has broad pharmacological functions including anti-virus, anti-inflammation, and neuroprotective. PURPOSE: We attempted to investigate the potential of Res in ameliorating PRV infection pathology in mice and decipher the mechanism of Res in treating PRV. METHODS: The mice were infected by PRV to investigate the protective effect of Res. Blood-brain barrier (BBB) permeability, H&E/Nissl/TUNEL staining, Real-time PCR and ELISA analyses were performed. Primary microglia and neuron were isolated from mice and cultured. The co-culture model of microglia and neuron was established by transwell. Immunofluorescence assay and flow cytometry were used. RESULTS: In this study, we showed that Res ameliorated brain damage by reducing BBB permeability in PRV-infected mice, and diminished the expressions of MMP-2, MMP-9 and ZO-1 in the cortex. Pathological changes of neurons by H&E/Nissl/TUNEL staining suggested that Res could alleviate neuronal lesions. Moreover, Res inhibited the expressions of pro-inflammatory factors (IL-6, TNF-α) and chemokines (CCL3, CXCL10, MCP-1), but increased the expressions of anti-inflammatory factors (IL-4, IL-10) and neurotrophic factor (TGF-ß, NGF and GDNF) in brain. In vitro cultured microglia cells, Res could suppress M1 microglia polarization and activate M2 microglia polarization. Co-culture of PRV-infected microglia with neuron cells by transwell system indicated that Res alleviated inflammatory response and neuronal apoptosis. CONCLUSION: This study provided evidence that Res could protect mice from PRV-induced encephalitis through regulation of microglia polarization and neuronal apoptosis suggesting the potential for treatment of viral encephalitis.

Research progress on the structure and biological diversities of 2-phenylindole derivatives in recent 20 years.

The privileged structure binds to multiple receptors with high affinity, which is helpful to the development of new bioactive compounds. Indole is classified as a privileged structure, which may be one of the most important structural categories in drug discovery. As a special subset of indole compounds, 2-phenylindole seems to be one of most promising forerunners of drug development. In this paper, 106 articles were referenced to review the structural changes, biological activities and structure-activity relationship of compounds in recent 20 years, and classified them according to their pharmacological activities, from several aspects, including anticancer, antibacterial, anti-inflammatory, analgesic, antiviral, anti-parasite, the biological activities target to central nervous system, et al. It also points out the importance of artificial intelligence (AI) technology in discovery of new 2-phenylindole compounds in a broader prospect. This review will provide some ideas for researchers to develop new indole drugs.

Response surface methodology for optimization of the extraction of polysaccharide from the roots of onosma hookeri clarke. var. longiforum duthie and its antioxidant capacity and immune activity.

Onosma hookeri Clarke. var. longiforum Duthie (OHC-LD), one of the traditional Tibetan medicine, has been found many functions, including removing heat to cool blood, nourishing lung and inhibiting bacteria. In order to study the polysaccharides in OHC-LD water extract, the optimal extraction progress of polysaccharides of the roots of OHC-LD by response surface method designed with three-factor three-level Box-Behnken method and the antioxidant capacity and immune activity of the crude polysaccharide were studied in this investigation. Under the best conditions, the extraction yield of polysaccharide was 3.19±0.09% (n = 3). After purification, the crude polysaccharide was obtained with polysaccharide contents of 42.57%, which demonstrated stronger DPPH scavenging activity than BHT at low concentrations (<625 µg/mL), and comparable ABTS radical scavenging activity as BHT at high concentrations (≥1250 µg/mL). Additionally, it also exhibited a certain cell proliferation activity and an enhancement of the phagocytic ability of RAW264.7 cells. This study revealed that the crude polysaccharide from the roots of OHC-LD might be exploited as a natural antioxidant and immune enhance agent in the future in both medical and food industry.

Isolation, structure identification, and immunostimulatory effects in vitro and in vivo of polysaccharides from Onosma hookeri Clarke var. longiforum Duthie.

BACKGROUND: This study characterized an acidic polysaccharide (OHC-LDPA) isolated from the medicinal and edible homologous plant Onosma hookeri Clarke var. longiforum Duthie. The structure of OHC-LDPA was elucidated based on the analysis of infrared, one-/two-dimensional nuclear magnetic resonance, and gas chromatography-mass spectrometry data. The immunostimulatory effects of OHC-LDPA were identified by both in vitro and in vivo models. RESULTS: The structure of OHC-LDPA was elucidated as a typical pectin polysaccharide, consisting of galacturonic acid, galactose, arabinose, and rhamnose as the primary sugars, with linear galacturonic acid as the main chain and arabinogalacturonic acid as the main branched components. OHC-LDPA could significantly stimulate the proliferation and phagocytosis of RAW264.7 macrophages and the release of nitric oxide in vitro. Also, it could accelerate the recovery of spleen and thymus indexes, enhance the splenic lymphocyte proliferation responses, and restore the levels of interleukin-2, interleukin-10, interferon-γ, and immunoglobulin G in the serum in a cyclophosphamide-induced immunosuppressed-mice model. In addition, OHC-LDPA could restore the intestinal mucosal immunity and reduce the inflammatory damage. CONCLUSION: OHC-LDPA could improve the immunity both in vitro and in vivo and could be used as a potential immunostimulant agent. © 2022 Society of Chemical Industry.

Cinnamaldehyde Resist Salmonella Typhimurium Adhesion by Inhibiting Type I Fimbriae.

Salmonella Typhimurium (S. Typhimurium), a common foodborne pathogen, severely harms the public and food security. Type I fimbriae (T1F) of S. Typhimurium, plays a crucial role in the pathogenic processes; it mediates the adhesion of bacteria to the mannose receptor on the host cell, assists the bacteria to invade the host cell, and triggers an inflammatory response. Cinnamaldehyde is the main ingredient in cinnamon essential oil. In this study, cinnamaldehyde was demonstrated to inhibit the expression of T1F by hemagglutination inhibition test, transmission electron microscopy, and biofilms. The mechanism of cinnamaldehyde action was studied by proteomics technology, PCR and Western blotting. The results showed that cinnamaldehyde can inhibit T1F in S. typhimurium without the growth of bacteria, by regulating the level of expression and transcription of fimA, fimZ, fimY, fimH and fimW. Proteomics results showed that cinnamaldehyde downregulated the subunits and regulators of T1F. In addition, the invasion assays proved that cinnamaldehyde can indeed reduce the ability of S. typhimurium to adhere to cells. The results of animal experiments showed that the colonization in the intestinal tract and the expression levels of inflammatory cytokine were significantly decreased, and the intestinal mucosal immune factors MUC1 and MUC2 were increased under cinnamaldehyde treatment. Therefore, cinnamaldehyde may be a potential drug to target T1F to treat Salmonella infections.

Study on the anti-biofilm mechanism of 1,8-cineole against Fusarium solani species complex.

Fungal-infections are mostly due to fungi in an adhering, biofilm-mode of growth and not due to planktonically growing, suspended-fungi. 1, 8-cineole is a natural product, which has been shown to possess antifungal effect. However, the anti-biofilm effect and mechanism of 1,8-cineole against Fusarium solani species complex has not reported previously. In this study, we found that 1,8-cineole has a good antifungal activity against F. solani with an MIC value of 46.1 µg/ml. Notably, 1,8-cineole showed good anti-biofilm formation activity against F. solani via inhibiting cell adhesion, hypha formation and decreasing the secretion of extracellular matrix at the concentration of ≥5.76 µg/ml. In addition, transcriptome sequencing analysis results showed that F. solani species complex genes related to ECM, protein synthesis and energy metabolism were down-expressed in the biofilms formation process treated with 1,8-cineole. In conclusion, these results show that 1,8-cineole has good anti-biofilm formation activity against F. solani species complex, and it exerts its anti-biofilm formation activity by downregulating of ergosterol biosynthetic genes, inhibiting adhesion, hindering the synthesis of ECM and interfering mitochondrial activity. This study suggests that 1,8-cineole is a promising anti-biofilm agent against F. solani species complex.

Benefits of neutral polysaccharide from rhizomes of Polygonatum sibiricum to intestinal function of aged mice.

One purified neutral polysaccharide fraction was obtained from the rhizome of Polygonatum sibiricum by DEAE ion exchange and gel chromatography. Structure elucidation was performed by methanolysis, methylation, FT-IR, and NMR. The results indicated that PSP-NP was composed of 1,4-ß-D-Gal,1, 4, 6-ß-D-Gal, T-α-D-Man,1, 4-α-D-Glc, and T-α-D-Glc with a molecular weight of 43.0 kDa. We supplied this polysaccharide to aged mice and found it is of benefits to intestinal functions, as indicated by better tissue integrity and motility, improved oxidative stress and inflammation, reduced intestinal permeability and serum LPS level, as well as balanced gut microbial composition and short-chain fatty acids production. These results display a novel Polygonatum sibiricum polysaccharide to improve the intestinal function of aged mice, which provides pieces of evidence for its further development and utilization.

Myricetin inhibits pseudorabies virus infection through direct inactivation and activating host antiviral defense.

Myricetin, a polyhydroxyflavone compound, is one of the main ingredients of various human foods and therefore also known as dietary flavonoids. Due to the continuous emergence of resistant strains of herpesviruses, novel control measures are required. In the present study, myricetin exhibited potent antiviral activity against pseudorabies virus (PRV), a model organism of herpesvirus. The suppression rate could reach up to 96.4% at a concentration of 500 µM in cells, and the 50% inhibitory concentration (IC50) was 42.69 µM. Moreover, the inhibitory activity was not attenuated by the increased amount of infective dose, and a significant reduction of intracellular PRV virions was observed by indirect immunofluorescence. A mode of action study indicated that myricetin could directly inactivate the virus in vitro, leading to inhibition of viral adsorption, penetration and replication in cells. In addition to direct killing effect, myricetin could also activate host antiviral defense through regulation of apoptosis-related gene expressions (Bcl-2, Bcl-xl, Bax), NF-κB and MAPK signaling pathways and cytokine gene expressions (IL-1α, IL-1ß, IL-6, c-Jun, STAT1, c-Fos, and c-Myc). In PRV-infected mouse model, myricetin could enhance the survival rate by 40% at 5 days post infection, and viral loads in kidney, liver, lung, spleen, and brain were significantly decreased. The pathological changes caused by PRV infection were improved by myricetin treatment. The gene expressions of inflammatory factors (MCP-1, G-CSF, IL-1α, IL-1ß, and IL-6) and apoptotic factors (Bcl-xl, Bcl-2, and Bax) were regulated by myricetin in PRV-infected mice. The present findings suggest that myricetin can effectively inhibit PRV infection and become a candidate for development of new anti-herpesvirus drugs.

Structural modification of octadecanoic acid-3,4-tetrahydrofuran diester and the acaricidal activity and mechanism of its derivatives against Sarcoptes scabiei var. Cuniculi.

Octadecanoic acid-3,4-tetrahydrofuran diester is a compound with acaricidal activity isolated and extracted from neem oil. In this study, a series of derivatives were obtained by structural modification of octadecanoic acid-3,4-tetrahydrofuran diester. The acaricidal activity of these derivatives indicated that introduction of benzyloxy substitution at the 2-position of the furan ring and the formation of a benzoate at the 3,4-position of the furan ring (benzoic acid-2-benzyloxy-3,4-tetrahydrofuran diester) could enhance the acaricidal activity. At concentration of 20, 10, and 5 mg/ml, the median lethal time (LT50) values of benzoic acid-2-benzyloxy-3,4-tetrahydrofuran diester were 16.138, 47.274, and 108.122 min, respectively. The LC50 value of benzoic acid-2-benzyloxy-3,4-tetrahydrofuran diester at 60 min was 5.342 mg/ml. Transmission electron microscopy showed that after treatment with benzoic acid-2-benzyloxy-3,4-tetrahydrofuran diester, the body structure of mites was destroyed; dermal organelles were dissolved; nuclear chromatin was ablated. Further, transcriptome sequencing analysis was used to get insight into the acaricidal mechanism of benzoic acid-2-benzyloxy-3,4-tetrahydrofuran diester. The results showed that its acaricidal mechanism is related to interfering "energy metabolism" in S. scabiei, including processes such as citric acid cycle, oxidative phosphorylation pathway and fatty acid metabolism. Additionally, through the activity detection of the mitochondrial complexes of S. scabiei, it was further verified that the acaricidal mechanism of benzoic acid-2-benzyloxy-3,4-tetrahydrofuran diester was related to the energy metabolism system of S. scabiei.

Geraniol inhibits biofilm formation of methicillin-resistant Staphylococcus aureus and increase the therapeutic effect of vancomycin in vivo.

Methicillin-resistant Staphylococcus aureus (MRSA) is among the common drug resistant bacteria, which has gained worldwide attention due to its high drug resistance and infection rates. Biofilms produced by S. aureus are known to increase antibiotic resistance, making the treatment of S. aureus infections even more challenging. Hence, inhibition of biofilm formation has become an alternative strategy for controlling persistent infections. In this study, we evaluated the efficacy of geraniol as a treatment for MRSA biofilm infection. The results of crystal violet staining indicated that 256 µg/mL concentration of geraniol inhibited USA300 biofilm formation by 86.13% and removed mature biofilms by 49.87%. Geraniol exerted its anti-biofilm effect by influencing the major components of the MRSA biofilm structure. We found that geraniol inhibited the synthesis of major virulence factors, including staphyloxanthin and autolysins. The colony count revealed that geraniol inhibited staphyloxanthin and sensitized USA300 cells to hydrogen peroxide. Interestingly, geraniol not only reduced the release of extracellular nucleic acids (eDNA) but also inhibited cell autolysis. Real-time polymerase chain reaction data revealed the downregulation of genes involved in biofilm formation, which verified the results of the phenotypic analysis. Geraniol increased the effect of vancomycin in eliminating USA300 biofilms in a mouse infection model. Our findings revealed that geraniol effectively inhibits biofilm formation in vitro. Furthermore, in combination with vancomycin, geraniol can reduce the biofilm adhesion to the implant in mice. This suggests the potential of geraniol as an anti-MRSA biofilm drug and can provide a solution for the clinical treatment of biofilm infection.

Microbiome analysis reveals microecological advantages of emerging ditchless rice-crayfish co-culture mode.

Ditchless rice-crayfish co-culture is an emerging model of rice-crayfish farming that circumvents the potential hazards of digging ditches in traditional rice-crayfish farming. However, due to the complex interactions among crayfish, ambient microbiota, and environmental variables, it is necessary to assess the differences in bacterial structure between ditchless and traditional rice-crayfish culture. In this study, the crayfish culture area in the Sichuan basin was selected as the study area, and the bacterial communities of two rice-crayfish culture systems were compared by high-throughput sequencing of 16S rDNA. The results showed that the ditchless system had lower water depth, higher dissolved oxygen, lower total ammonia nitrogen and lower morbidity. There are intuitive differences in the composition of environmental bacterial communities due to environmental changes, even if they are similar in composition at the phylum level. Microbiota in sediments from ditchless systems appear to produce less ammonia nitrogen. The abundance of the pathogens colonizing the intestine of ditchless crayfish was lower than ditched one, and the composition was similar to water. Ditch-farmed crayfish appear to be more susceptible to environmental microbes and have a more fragile intestinal structure. Water depth and dissolved oxygen are the main environmental factors that determine the distribution of microbiota. This study is the first to investigate the bacterial ecology of a ditchless rice- crayfish farming system. The results show that the ditchless rice-crayfish culture model has a more superior bacterial system than the traditional rice-crayfish culture.

A study of the antibacterial mechanism of pinocembrin against multidrug-resistant Aeromonas hydrophila / Un estudio del mecanismo antibacteriano de la pinocembrina contra Aeromonas hydrophila resistente a múltiples fármacos

Aeromonas hydrophila is a common pathogen in fish that has caused severe economic losses in aquaculture worldwide. With the emergence of bacterial resistance, it is necessary to develop new drugs to combat bacterial infection, particularly for multidrug-resistant bacteria. In this study, the antibacterial activity of pinocembrin was investigated by observing bacterial growth and microscopic structure, and its mechanism of action was identified by investigating its effect on protein and DNA. The antibacterial susceptibility test indicated that pinocembrin inhibits A. hydrophila growth. The minimal inhibitory concentration and minimum bactericidal concentration were 256 μg/mL and 512 μg/mL, respectively. Ultrastructurally, the bacteria treated with pinocembrin showed surface roughness and plasmolysis. When bacteria were treated with 512 μg/mL pinocembrin, lactate dehydrogenase activity and soluble protein content decreased significantly, and electrical conductivity and DNA exosmosis levels increased by 4.21 ± 0.64% and 15.98 ± 1.93 mg/L, respectively. Staining with 4′, 6-Diamidino-2-phenylindole showed that the nucleic acid fluorescence intensity and density decreased after the treatment with pinocembrin. Pinocembrin may inhibit the growth of A. hydrophila by increasing cell membrane permeability and affecting protein and DNA metabolism. Thus, pinocembrin is a candidate drug for the treatment of A. hydrophila infection in aquaculture.(AU)

Protective Effects of Cinnamaldehyde on the Oxidative Stress, Inflammatory Response, and Apoptosis in the Hepatocytes of Salmonella Gallinarum-Challenged Young Chicks.

The development of novel therapeutics to treat multidrug-resistant pathogenic infections like Salmonella gallinarum is the need of the hour. Salmonella infection causes typhoid fever, jaundice, and Salmonella hepatitis resulting in severe liver injury. Natural compounds have been proved beneficial for the treatment of these bacterial infections. The beneficial roles of cinnamaldehyde due to its antibacterial, anti-inflammatory, and antioxidative properties have been determined by many researchers. However, alleviation of liver damage caused by S. gallinarum infection to young chicks by cinnamaldehyde remains largely unknown. Therefore, this study was performed to identify the effects of cinnamaldehyde on ameliorating liver damage in young chicks. Young chicks were intraperitoneally infected with S. gallinarum and treated with cinnamaldehyde orally. Liver and serum parameters were investigated by qRT-PCR, ELISA kits, biochemistry kits, flow cytometry, JC-1 dye experiment, and transcriptome analysis. We found that ROS, cytochrome c, mitochondrial membrane potential (Ψm), caspase-3 activity, ATP production, hepatic CFU, ALT, and AST, which were initially increased by Salmonella infection, significantly (P < 0.05) decreased by cinnamaldehyde treatment at 1, 3, and 5 days postinfection (DPI). In addition, S. gallinarum infection significantly increased proinflammatory gene expression (IL-1ß, IL-6, IL-12, NF-κB, TNF-α, and MyD-88) and decreased the expression of anti-inflammatory genes (IL-8, IL-10, and iNOS); however, cinnamaldehyde reverted these effects at 1, 3, and 5 DPI. Transcriptome analysis showed that S. gallinarum modulates certain genes of the AMPK-mTOR pathway for its survival and replication, and these pathway modulations were reversed by cinnamaldehyde treatment. We concluded that cinnamaldehyde ameliorates inflammation and apoptosis by suppressing NF-Kß/caspase-3 pathway and reverts the metabolic changes caused by S. gallinarum infection via modulating the AMPK-mTOR pathway. Furthermore, cinnamaldehyde has antibacterial, anti-inflammatory, antioxidative, and antiapoptotic properties against S. gallinarum-challenged young chicks and can be a candidate novel drug to treat salmonellosis in poultry production.