Comparison of the bacteriostatic effects of quaternary ammonium compounds and their combinations on a dairy farm environment and the microbial contamination of dairy products.

Disinfection is key for controlling microbial contamination and ensuring the safe production of milk and dairy products. In this study, we developed a new disinfection method using quaternary ammonium surfactant N-dodecyl-2-(pyridin-1-yl) acetamide chloride as the main component to form a bactericidal complex with either chlorhexidine acetate or glutaraldehyde, and we evaluated the bactericidal effects, safety, and clinical application value of the compound disinfectants. An in vivo acute oral toxicity assay in mice showed an LD50 > 5000 mg/kg body weight without abnormality in pathological tissue sections. Comparison with commercially available products also showed that they have outstanding bactericidal effects. Clinical trials proved that the compound disinfectants have excellent bactericidal effects on the air and ground of the dairy farm and on the skin of cattle, especially in a dairy farm environment. Our findings confirm that the new compound disinfectants have excellent bactericidal performance and are safe to use as disinfectants to prevent mastitis and contamination of the cattle farm environment.

La désinfection est essentielle pour maitriser la contamination microbienne et garantir une production sécuritaire de lait et de produits laitiers. Dans cette étude, nous avons développé une nouvelle méthode de désinfection utilisant l'ammonium quaternaire tensioactif d'acétamide de chlorure de N-dodécyl-2-(pyridin-1-yl) comme composant principal pour former un complexe bactéricide avec l'acétate de chlorhexidine ou le glutaraldéhyde, et nous avons évalué les effets bactéricides, la sécurité et la valeur d'application clinique des désinfectants composés. Un test de toxicité orale aiguë in vivo chez la souris a montré une DL50 > 5000 mg/kg de poids corporel sans anomalie pathologique dans les sections de tissus. La comparaison avec les produits disponibles dans le commerce a également montré qu'ils ont des effets bactéricides remarquables. Des essais cliniques ont démontré que les désinfectants composés ont d'excellents effets bactéricides sur l'air et le sol de la ferme laitière et sur la peau des bovins, en particulier dans un environnement de ferme laitière. Nos résultats confirment que les nouveaux désinfectants composés ont d'excellentes performances bactéricides et sont sécuritaires à utiliser comme désinfectants pour prévenir la mammite et la contamination de l'environnement de l'élevage bovin.(Traduit par Docteur Serge Messier).

Metabolomic and Proteomic Profiles Reveal the Dynamics of Primary Metabolism during Seed Development of Lotus (Nelumbo nucifera).

Sacred lotus (Nelumbo nucifera) belongs to the Nelumbonaceae family. Its seeds are widely consumed in Asian countries as snacks or even medicine. Besides the market value, lotus seed also plays a crucial role in the lotus life cycle. Consequently, it is essential to gain a comprehensive understanding of the development of lotus seed. During its development, lotus seed undergoes cell division, expansion, reserve accumulation, desiccation, and maturation phases. We observed morphological and biochemical changes from 10 to 25 days after pollination (DAP) which corresponded to the reserve synthesis and accumulation phase. The volume of the seed expanded until 20 DAP with the color of the seed coat changing from yellow-green to dark green and gradually fading again. Starch and protein rapidly accumulated from 15 to 20 DAP. To further reveal metabolic adaptation, primary metabolites and proteins profiles were obtained using mass spectrometry based platforms. Metabolites and enzymes involved in sugar metabolism, glycolysis, TCA cycle and amino acid metabolism showed sequential dynamics enabling the clear separation of the different metabolic states during lotus seed development. The integration of the data revealed a highly significant metabolic switch at 15 DAP going through a transition of metabolically highly active tissue to the preparation of storage tissue. The results provide a reference data set for the evaluation of primary metabolism during lotus seed development.

Differential Molecular Responses of Rapeseed Cotyledons to Light and Dark Reveal Metabolic Adaptations toward Autotrophy Establishment.

Photosynthesis competent autotrophy is established during the postgerminative stage of plant growth. Among the multiple factors, light plays a decisive role in the switch from heterotrophic to autotrophic growth. Under dark conditions, the rapeseed hypocotyl extends quickly with an apical hook, and the cotyledon is yellow and folded, and maintains high levels of the isocitrate lyase (ICL). By contrast, in the light, the hypocotyl extends slowly, the cotyledon unfolds and turns green, the ICL content changes in parallel with cotyledon greening. To reveal metabolic adaptations during the establishment of postgerminative autotrophy in rapeseed, we conducted comparative proteomic and metabolomic analyses of the cotyledons of seedlings grown under light versus dark conditions. Under both conditions, the increase in proteases, fatty acid ß-oxidation and glyoxylate-cycle related proteins was accompanied by rapid degradation of the stored proteins and lipids with an accumulation of the amino acids. While light condition partially retarded these conversions. Light significantly induced the expression of chlorophyll-binding and photorespiration related proteins, resulting in an increase in reducing-sugars. However, the levels of some chlorophyllide conversion, Calvin-cycle and photorespiration related proteins also accumulated in dark grown cotyledons, implying that the transition from heterotrophy to autotrophy is programmed in the seed rather than induced by light. Various anti-stress systems, e.g., redox related proteins, salicylic acid, proline and chaperones, were employed to decrease oxidative stress, which was mainly derived from lipid oxidation or photorespiration, under both conditions. This study provides a comprehensive understanding of the differential molecular responses of rapeseed cotyledons to light and dark conditions, which will facilitate further study on the complex mechanism underlying the transition from heterotrophy to autotrophy.

Induction and quantitative proteomic analysis of cell dedifferentiation during callus formation of lotus (Nelumbo nucifera Gaertn.spp. baijianlian).

Lotus is an aquatic plant with high nutritional, ornamental and medical values. Its callus formation is crucial for germplasm innovation by genetic transformation. In this study, embryogenic callus was successfully induced on appropriate medium using cotyledons at 12days after pollination as explants. To dissect cellular dedifferentiation and callus formation processes at the proteome level, cotyledons before and tissues from 10 to 20days after induction were sampled for shotgun proteomic analysis. By applying multivariate statistics 91 proteins were detected as differentially regulated, and sorted into 6 functional groups according to MapMan ontology analysis. Most of these proteins were implicated in various metabolisms, demonstrating that plant cells underwent metabolism reprogramming during callus induction. 14.3% proteins were associated with stress and redox, indicating that the detached explants were subjected to a variety of stresses; 13.2% were cell and cell wall-related proteins, suggesting that these proteins played important roles in rapid cell division and proliferation. Some proteins were further evaluated at the mRNA levels by quantitative reverse transcription PCR analysis. In conclusion, the results contributed to further deciphering of molecular processes of cellular dedifferentiation and callus formation, and provided a reference data set for the establishment of transgenic transformation in lotus.