Treponema pallidum was successfully grown in subcutaneous chambers in golden hamsters. Abnormally long forms of T. pallidum were found in these chambers. The cause of this abnormality may possibly be due to their being coated with antibody which could inhibit cell division or render the organism avirulent or both. T. pallidum was successfully passaged between hamsters but with a possible diminu...

As previous reports suggested that a hyaluronidase is involved in tissue invasion of Entamoeba histolytica, we searched for such an activity in trophozoite extracts. A hyaluronidase activity was not detectable in long-term cultures or in amoebae freshly passaged through a gerbil liver, as evidenced by four different techniques.

Leishmania chagasi causes visceral leishmaniasis, a potentially fatal disease of humans. Within the sand fly vector, L. chagasi replicates as promastigotes which undergo complex changes in morphology as they progress from early stage procyclic promastigotes, to intermediate stage leptomonad and nectomonad promastigotes, and ultimately to terminal stage metacyclic promastigotes that are highly i...

Low pathogenic Avian Influenza (AI) virus has the ability to evolve to high pathogenic viruses resulting in significant economic losses in the poultry sector. This study aims at assessing the impact of H9N2 viral passaging in broilers and its relatedness to pathogenicity and amino acid (a.a) sequences of the hemagglutinin (HA) cleavage site and neuraminidase (NA) stalk. The original H9N2 AI vir...

The alternating host cycle and persistent vector infection may constrain the evolution of arboviruses. To test this hypothesis, eastern equine encephalitis virus was passaged in BHK or mosquito cells, as well as in alternating (both) host cell passages. High and low multiplicities were used to examine the effect of defective interfering particles. Clonal BHK and persistent mosquito cell infecti...

The use of adipose-derived stem cells (ADSC) in regenerative medicine is rising due to their plasticity, capacity of differentiation and paracrine and trophic effects. Despite the large number of cells obtained from adipose tissue, it is usually not enough for therapeutic purposes for many diseases or cosmetic procedures. Thus, there is the need for culturing and expanding cells in-vitro for se...

Purpose The first aim of this study was to develop a novel inactivated porcine epidemic diarrhea virus (PEDV) vaccine using the recently isolated Korean PEDV QIAP1401 strain and to evaluate its protective efficacy in growing pigs. The second was to determine the optimum adjuvant formulation of the inactivated PEDV vaccine that induces protection against viral challenge. Materials and Methods ...

Eleven strains of Aeromonas salmonicida were passaged twice by intraperitoneal injection through rainbow trout and reisolated from the kidney of moribund fish. The surface characteristics and virulence of the strains changed following passage through fish. None of the in vitro tests used could effectively predict the in vivo virulence.

Under standard culture conditions, tumor cells are exposed to 20% O(2), whereas the mean tumor oxygen levels within the tumor are much lower. We demonstrate, using low-passaged human tumor cell cultures established from glioma, that a reduction in the oxygen level in these cell cultures dramatically increases the percentage of CD133 expressing cells.