We demonstrated that oxidative stress plays a role in freeze-thaw-induced killing of Campylobacter coli following analysis of mutants deficient in key antioxidant functions. Superoxide anions, but not H(2)O(2), were formed during the freeze-thaw process. However, a failure to detoxify superoxide anions may lead to spontaneous disproportionation of the radicals to H(2)O(2).

The effects of storage temperatures, repeated freeze-thaw cycles, or delays in separating plasma or serum from blood samples are largely unknown for heat shock protein 27 (HSP27). We evaluated (1) the imprecision of the HSP27 assay used in this study; (2) the in vitro stability of HSP27 in blood samples stored at 4°C for up to 6 hr with immediate and delayed serum/plasma separation from cells; ...

OBJECTIVE To evaluate the maturation and post-thaw survival rates of immature oocytes to determine whether in vitro maturation (IVM) should be attempted prior to or after cryopreservation. DESIGN Nonrandomized observational study. SETTING Private academic and clinical reproductive center. PATIENT(S) Patients (n = 71) who donated immature unusable oocytes after vaginal oocyte retrieval (VO...

The effect of bacterial cellulose (BC) on the freeze-thaw stability of rice starch gels during 5 freeze-thaw cycles were investigated, using scanning electron microscopy (SEM), rapid visco analyzer (RVA), X-ray diffractometry (XRD), differential scanning calorimetry (DSC) and textural analyzer (TA). SEM micrographs of freeze-thaw gels showed that smaller pore size and a thicker surrounding matr...

Numerous diseases are carried and can be transmitted from the African buffalo (Syncerus caffer) to livestock. Therefore, buffaloes may only be moved with a special transport permit. Disease-free buffaloes are in demand amongst private game farmers. Current disease-free animals derive from a small genetic pool and hence there is a special interest in bringing new genetic material into the diseas...

The food-borne pathogen Listeria monocytogenes can grow in a wide range of temperatures, and several key virulence determinants of the organism are expressed at 37 degrees C but are strongly repressed below 30 degrees C. However, the impact of growth temperature on the ability of the bacteria to tolerate environmental stresses remains poorly understood. In other microorganisms, cold acclimation...

Freezing and thawing of the land surface affects ecosystem and hydrological processes, the geotechnical properties of soil and slope stability. Currently, available datasets on land surface state lack either sufficient temporal or spatial resolution to adequately characterize the complexity of freeze/thaw transition period dynamics. Surface state changes can be detected using microwave remote s...

A comparative approach was used to evaluate the cryosurvival of turkey and crane sperm frozen in a dimethylacetamide (DMA) cryodiluent supplemented with osmoprotectants and ATP. A range (6-26%) of DMA concentrations was used alone or in combination with ATP (30, 60 or 118mM) or one of the following osmoprotectants: (1) sucrose (turkey, 8.0%; crane, 5.0%); (2) 5.0% sucrose and 5.0% trehalose; or...

BACKGROUND An effect of cryopreservation on human sperm is sublethal cryodamage, in which cell viability post-thaw is lost more rapidly at later times than in fresh cells. OBJECTIVE This study examined whether the addition of an antioxidant to cryopreservation medium could improve the post-thaw parameters and evaluation of sperm chromatin quality of cryopreserved human spermatozoa from men wi...

Thawing of permafrost soils is expected to stimulate microbial decomposition and respiration of sequestered carbon. This could, in turn, increase atmospheric concentrations of greenhouse gasses, such as carbon dioxide and methane, and create a positive feedback to climate warming. Recent metagenomic studies suggest that permafrost has a large metabolic potential for carbon processing, including...