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We employed DNA sequence variation at two mitochondrial (control region, COI) regions from 212 individuals of Galaxias platei (Pisces, Galaxiidae) collected throughout Patagonia (25 lakes/rivers) to examine how Andean orogeny and the climatic cycles throughout the Quaternary affected the genetic diversity and phylogeography of this species. Phylogenetic analyses revealed four deep genealogical lineages which likely represent the initial division of G. platei into eastern and western lineages by Andean uplift, followed by further subdivision of each lineage into separate glacial refugia by repeated Pleistocene glacial cycles. West of the Andes, refugia were likely restricted to the northern region of Patagonia with small relicts in the south, whereas eastern refugia appear to have been much larger and widespread, consisting of separate northern and southern regions that collectively spanned most of Argentinean Patagonia. The retreat of glacial ice following the last glacial maximum allowed re-colonization of central Chile from nonlocal refugia from the north and east, representing a region of secondary contact between all four glacial lineages. Northwestern glacial relicts likely followed pro-glacial lakes into central Chilean Patagonia, whereas catastrophic changes in drainage direction (Atlantic --Pacific) for several eastern palaeolakes were the likely avenues for invasions from the east. These mechanisms, combined with evidence for recent, rapid and widespread population growth could explain the extensive contemporary distribution of G. platei throughout Patagonia.

Changes in lake and stream habitats during the growth and retreat of Pleistocene glaciers repeatedly altered the spatial distributions and population sizes of the aquatic fauna of the southern Andes. Here, we use variation in mtDNA control region sequences to infer the temporal dynamics of two species of southern Andean fish during the past few million years. At least five important climate events were associated with major demographic changes: (i) the widespread glaciations of the mid-Pliocene (c. 3.5 Ma); (ii) the largest Patagonian glaciation (1.1 Ma); (iii) the coldest Pleistocene glaciation as indicated by stacked marine delta(18)O (c. 0.7 Ma); (iv) the last southern Patagonian glaciation to reach the Atlantic coast (180 ka); and (v) the last glacial maximum (LGM, 23-25,000 years ago). The colder-water inhabitant, Galaxias platei, underwent a strong bottleneck during the LGM and its haplotype diversity coalesces c. 0.7 Ma. In contrast, the more warm-adapted and widely distributed Percichthys trucha showed continuous growth through the last two glacial cycles but went through an important bottleneck c. 180,000 years ago, at which time populations east of the Andes may have been eliminated. Haplotype diversity of the most divergent P. trucha populations, found west of the Andes, coalesces c. 3.2 Ma. The demographic timelines obtained for the two species thus illustrate the continent-wide response of aquatic life in Patagonia to climate change during the Pleistocene, but also show how differing ecological traits and distributions led to distinctive responses.

Ultrahigh temperature sterilized canned puddings occasionally exhibit spoilage in the form of a dramatic loss of viscosity or thinning. Studies on a concentrated fraction of spoiled pudding indicate that thinning was due to a heat-resistant amylase. The concentrate was obtained by centrifugation and ultrafiltration of the thinned pudding. Ultrafiltration characteristics of the active agent indicate a molecular weight of 1–30 × 104 daltons. The agent attacked starch with a decrease in iodine-binding capability and an increase in reducing units. Treatment of the concentrate with proteolytic enzymes decreased enzymatic activity by 50%; treatment with sodium ethylene diaminetetraacetate decreased activity by 80%. The levels of starch and pH of the spoiled puddings were suitable for action of the amylase, and the enzyme was quite active at normal and elevated room temperatures.

The α-amylase of the thermophile Bacillus stearothermophilus 1518 was used as a model enzyme to examine the heat resistance of a bacterial amylase at ultrahigh temperature in a starch-based pudding. When heated in the laboratory pudding at 143°C for the equivalent of 22.2 set, approximately 26% of the initial amylolytic activity was retained. The presence or absence of individual ingredient groups (starch, caseinate-nonfat dry milk, oilemulsifiers, salts, or sucrose) of the pudding had no significant effect on amylase heat resistance. A combination of any two of the starch, caseinate-nonfat dry milk, or oil-emulsifier ingredients were found to be important for thermostability. The amylase of the mesophile Xanthomonas campestris 13957–2 exhibited similar thermal inactivation characteristics.

Modified PA3679 agar (MPA3679A) was formulated as a plating medium to provide improved recovery of Clostridium sporogenes Putrefactive Anaerobe (PA) 3679 spores. A comparative study of MPA3679A and two currently used plating media, Yeast extract agar (YEA), and Peptone trypticase agar (PTA), showed that MPA3679A was superior for the recovery of heat activated and heat stressed spores. Further, when this medium was altered for use as an inoculated pack subculture medium, recovery of severely heat stressed spores was superior to that in the previously recommended PA3679 agar, also known as T-Best.

The heat resistant lipase of Pseudomonas spp. MC50 hydrolyzed coconut oil, corn oil, butter oil and olive oil. Lipase activity was maximum at 1% corn oil. The effects of pH and temperature on lipase activity varied with the substrate. The pH optima were in the range pH 8–9; the temperature optima were in the range 35–40°C. Of several emulsifiers tested, four supported significant lipase actiivity, and three supported no lipase activity and may have inhibited the lipase. Emulsifier concentration influenced lipase activity. All stabilizers tested supported lipase activity; above 0.36% stabilizer concentration had no effect.

Pseudomonas spp. MC50 produced an extra-cellular lipase that was extremely heat resistant at 100–150°C when heated in water or emulsions. The D-values ranged from 40 min at 100°C to 84 sec at 150°C. The zD-vallue was 36°C. When heated in water, the lipase exhibited greatest survival at pH 8.5. Below pH 6.5, survival was less than 10% of that at pH 8.5. Survival of lipase heated in emulsions was affected somewhat by the type of oil, corn oil concentration, and type of emulsifier. Type of stabilizer or stabilizer concentration had little effect on lipase survival. Lipase treated with ethylenediaminetetraacetate (EDTA) was fully heat resistant in water; survival declined when lipase was heated in CaCl2 solutions of 3–120 mM.