title: Evolution of culture broth rheological properties during propagation of the entomopathogenic nematode Steinernema carpocapsae, in submerged monoxenic culture.
abstract: This article presents the evolution of culture broth rheological properties during monoxenic cultures of Steinernema carpocapsae in cylindrical bottles agitated orbitally. Rheological properties were evaluated in simple-shear flow conditions and were well-modeled by the Ostwald-de Waele model. Rheological properties varied from slightly dilatant, n = 1.2 (-), to moderately pseudoplastic flow behavior, n = 0.6 (-). Nematode concentrations increased from 750 +/- 190 to 130 900 +/- 6900 nematodes/mL, and the apparent viscosity (eta(a)) evolved from 4.5 +/- 0.7 to 46.6 +/- 3.2 mPa.s during the fermentations. Rheological behavior did not appear to be strongly influenced by nematode number and/or its stage of development; however, the release of substances from the decomposition of nematode cadavers appeared to be of great importance. Among the different developmental stages of the nematodes, only juveniles of the first stage (J1) were highly susceptible to the shearing conditions tested (shear stress, tau(r)()(theta), from 0.9 to 3.5 Pa during periods of 80-100 min), resulting in the viability loss of 85% of J1 nematodes.
authors.affiliation: Departamento de Biotecnología y Bioingeniería, CINVESTAV-IPN, Av. Instituto Politécnico Nacional No. 2508, San Pedro Zacatenco CP 07360, México DF, Mexico.
authors.forename: Norberto
authors.initials: N
authors.lastname: Chavarría-Hernández
authors.forename: Adriana Inés
authors.initials: AI
authors.lastname: Rodríguez-Hernández
authors.forename: Fermín
authors.initials: F
authors.lastname: Pérez-Guevara
authors.forename: Mayra
authors.initials: M
authors.lastname: de la Torre
mesh_terms: D000818:Animals; D005075:Biological Evolution; D019149:Bioreactors; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D002478:Cells, Cultured; D018920:Coculture Techniques / Q000379:methods; D003470:Culture Media / Q000737:chemistry; D007185:Incubators; D009038:Motion; D009348:Nematoda / Q000145:classification / Q000254:growth & development* / Q000378:metabolism / Q000382:microbiology; D011157:Population Dynamics; D011786:Quality Control; D012212:Rheology / Q000379:methods*; D033081:Shear Strength; D013045:Species Specificity; D013559:Symbiosis / Q000502:physiology; D014783:Viscosity; D020593:Xenorhabdus / Q000166:cytology / Q000254:growth & development* / Q000472:pathogenicity
chemical_list: D003470:Culture Media