Toxoplasma gondii genotyping from free-range chickens (Gallus gallus domesticus) in a rural area of Rio Grande do Sul, Brazil / [Genotipagem de Toxoplasma gondii em galinhas domésticas em uma área rural do Rio Grande do Sul, Brasil]

Free-range chickens may ingest oocysts of T. gondii present in the environment and consequently harbor virulent strains of this parasite in different tissues, without any clinical signs. Isolation of T. gondii through bioassays on mice and cats from naturally infected chicken tissues has been described in several countries, demonstrating the importance of free-range chickens in the transmission of this parasite. The aim of this study was the genotypic characterization of T. gondii isolates obtained from naturally infected free-range chickens in a rural area of the state of Rio Grande do Sul, Brazil. Brain and heart tissue from 12 chickens seropositive for T. gondii were processed using peptic digestion technique for parasite isolation. From 12 samples subjected to mouse bioassay, nine isolates were obtained. RFLP-PCR genotypic characterization was performed using 11 genetic markers: SAG1, 5'-3'SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 and Apico. Genetic characterization of the isolates revealed the presence of five atypical genotypes according to ToxoDB (# 11, # 55, # 64, # 140 and # 163). Our results showed a wide genetic diversity of T. gondii in free-range chickens in this region.(AU)

Galinhas criadas ao ar livre podem ingerir oocistos de T. gondii presentes no ambiente e, com isso, albergar cepas virulentas desse parasita em diferentes tecidos, sem sinais clínicos. O isolamento de T. gondii por meio de bioensaios em camundongos e gatos, a partir de tecidos de galinhas naturalmente infectadas, tem sido descrito em vários países. Isso demonstra a importância das galinhas caipiras na epidemiologia desse parasita. O objetivo deste trabalho foi caracterizar genotipicamente isolados de T. gondii obtidos de galinhas caipiras naturalmente infectadas em uma área rural do município de Santa Maria, estado do Rio Grande do Sul, Brasil. Fragmentos de cérebro e de coração, de 12 galinhas soropositivas para T. gondii, foram processados pela técnica de digestão péptica para isolamento do parasita. Das 12 amostras submetidas a bioensaio com camundongos, nove isolados foram obtidos. A caracterização genotípica por RFLP-PCR foi realizada utilizando-se 11 marcadores genéticos: SAG1, 5'-3'SAG2, alt.SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1 e Apico e revelou a presença de cinco genótipos atípicos de acordo com o ToxoDB (# 11, # 55, # 64, # 140 e # 163). Os resultados mostraram uma ampla diversidade genética de T. gondii em galinhas caipiras nessa região.(AU)

Heterotransplantation of canine sarcoma cells (BLU284) in athymic (nude) mice.

Undifferentiated canine sarcoma cells from a primary lesion were implanted subcutaneously in athymic (nude) mice. Tumors were implanted at 2 sites in each of 4 mice, and 6 of the 8 inoculation sites developed into tumors. Tumors grew and invaded surrounding tissues, as shown by histologic examination. Karyotype analysis verified that tumors were of canine origin. Cells from this tumor were serially heterotransplanted 26 times without consistent change in growth rate. Once established in nude mice, samples from 2 generations of this canine sarcoma cell line were stored cryogenically and were implanted into nude mice. Over 26 generations, 93.7% of fresh implants developed into tumors. Preliminary screening of antineoplastic drugs indicated that this tumor line was sensitive to cyclophosphamide and vincristine. The difference in sensitivity of this heterotransplanted tumor in nude mice toward the various antineoplastic agents provides a useful model for the elucidation of biochemical bases of antineoplastic drug resistance in tumors.

Heterotransplantation of equine carcinoma cells in athymic (nude) mice.

Nondifferentiated equine carcinoma cells from a primary lesion were implanted subcutaneously in athymic (nude) mice. The cells were implanted at 2 sites each in 3 mice. At 1 of the 6 inoculation sites, a tumor developed, which invaded surrounding tissues, as shown by histopathologic examination. Karyotype analysis verified that the tumor was of equine origin. Cells from this tumor were serially heterotransplanted 20 times without change in growth rate. Once established in nude mice, this equine carcinoma cell line was stored cryogenically and then was successfully reimplanted into nude mice. All of the implants developed into tumors, over 20 generations. Preliminary screening of antineoplastic drugs indicated that this tumor line is sensitive to cyclophosphamide. Because of its ease of handling and high reimplantation efficiency, this tumor line should prove useful in equine cancer research.