Effects of activated complement components on enzyme secretion by macrophages

Purified cleavage products of the guinea-pig complement component C3, namely C3b and C3a, interact with guinea-pig and mouse macrophages in culture to induce a dose- and time dependent release of lysosmal enzymes into the medium. In the case of C3b the selectivity of the release of hydrolases, which occurs without cell killing, is shown by morphological observations and the failure of lactate dehydrogenase to appear in the medium. However, lysosomal enzyme release in the presence of C3a is accompanied by loss of cellular lactate dehydrogenase. Preincubation of C3b with anti-C3 Fab inhibits its attachment to macrophages, after which there is hardly detectable enzyme release into the medium. We have found that stimulated macrophages release enzyme(s) which can cleave C3, generating more C3b either directly or via the alternative pathway; the C3b so formed would induce further enzyme release. This amplification system may provide an explanation for the ability of macrophages to generate mediators of inflammation and cause tissue damage and degradation at sites of chronic inflammation while retaining their ability for long periods of time.     

Postbite elevation in tongue-flicking rate by an iguanian lizard,Dipsosaurus dorsalis

The herbivorous iguanid lizardDipsosaurus dorsalis exhibited PETF (postbite elevation in tongue-flicking rate), an increase in tongue-flicking rate after experimental removal from the mouth of food that had been bitten. This was demonstrated by a significantly higher tongue-flick rate after having bitten food than in three experimental conditions controlling for responses to the experimental setting, sight of food, and mechanical disturbance caused by the experimental removal of food from a lizard's mouth. As in most other families of lizards, PETF was brief, occurring only during the first minute. Lizards are divided into two major suprafamilial taxa, Iguania and Scleroglossa, consisting of carnivorous species characterized by two major foraging modes, ambush and active, and of herbivores and omnivores. PETF is absent in the two families of carnivorous iguanian lizards studied that are ambush foragers but present in three families of scleroglossan lizards that are active foragers. However, PETF is absent in the two species studied in a scleroglossan family, Gekkonidae, which forages by ambush, and present in an iguanian herbivore, as reported herein. We propose that the presence or absence of PETF, in addition to its phylogenetic determinants, is adaptively adjusted to foraging mode.     

Bioluminescence ATP monitoring as a surrogate marker for microbial load on hands and surfaces in the home

To evaluate the validity and reliability of adenosine triphosphate (ATP) monitoring as a surrogate marker for cleanliness, the kitchen table surface in 225 inner-city homes was sampled by microbiologic culture and by two types of biomass monitoring systems (HY-LiTEtrade mark 2 ATP System and HY-RiSE Colour Hygiene Test Strip, EM Science, Gibbstown, New Jersey, USA). A randomly selected hand of the homemaker (n = 225) was also cultured and sampled with the ATP monitoring system immediately after handwashing. Log microbial counts on hands ranged from 3.2 to 7.0 and from the table, 1.0 to 5.5. While the traditional ATP readings (HY-LiTE) and the color strips were significantly correlated (R = 0.18, P = 0.01), there was no significant correlation between the ATP monitor readings and the colony-forming units counts on either the hands (R = 0.03, P = 0.62) or the table (R = 0.04, P = 0.58). Such biomass measurements are not a substitute for quantitation of microbial load.     

A research note on radio frequency transponder effects on bloom of beef muscle

This study was designed to determine if radio frequency transponders affect the bloom of tray-packed beef muscle. A radio frequency identification (RFID) passive transponder was applied to the overwrap film of beef strip loin steaks. Overwrapped tray packs were vacuum packaged and stored for two days at 4 °C. Samples were removed from the vacuum package and CIE L(*), a(*), and b(*) values were measured through the overwrap until CIE a(*) values stabilized (40 min). Overwrap was removed and CIE L(*), a(*), and b(*) values were measured directly below the RFID and an adjacent control area for 40 min. All CIE L(*), a(*), and b(*) values were statistically different (P<0.05) directly below the RFID when compared to the adjacent control area. The greatest differences were observed in the initial values and may be of consumer concern. After achieving full bloom (40 min post-overwrap removal), the difference between these areas were negligible.     

Metabolism of the soil and groundwater contaminants,ethylene dibromide and trichloroethylene,by the tropical leguminous tree,Leuceana leucocephala

Ethylene dibromide (EDB; dibromoethane) and trichloroethylene (TCE) are hazardous environmental pollutants. The use of plants to treat polluted sites and groundwater, termed phytoremediation, requires plants that can both effectively remove the pollutant as well as grow in the climatic region of the site. In this paper, we report that the tropical leguminous tree, Leuceana leucocephala var. K636, is able to take up and metabolize EDB and TCE. The plants were grown in sterile hydroponic solution without its symbiont, Rhizobium. EDB and TCE were both metabolized by the plant, as indicated by the formation of bromide ion from EDB and trichloroethanol from TCE. Each plant organ was independently capable of debromination of EDB. L. leucocephala is being used to treat perched groundwater as part of a remedial alternative to address an accidental EDB spill in Hawaii. Bromide levels of plant tissues from the trees grown in the phytoremediation treatment cells at the Hawaii Site were elevated, indicating uptake and degradation of brominated compounds in the trees. This report is the first evidence of a tropical tree effectively metabolizing these common organic pollutants.     

A framework for the design of wildlife conservation corridors With specific application to southwestern Ontario

Natural disturbances and human development can cause habitat fragmentation. Plant and animal populations can become isolated, but wildlife corridors can potentially alleviate the problem by providing linkages between isolated patches of natural areas. These connecting corridors need to be designed to create habitat appropriate for target species.This study developed a framework for design of wildlife corridors which considered both critical corridor attributes and target species. It provided a methodology for use in designing corridors to ensure appropriate species composition. Objectives included identifying and analyzing attributes which constitute a corridor. An ‘ecosystem approach’ for selecting guilds of target species was used. The framework was applied to a fragmented landscape case study in southwestern Ontario, Canada.Results indicated that, by applying this framework to a fragmented landscape, ecologically appropriate corridors could be designed when corridor attributes and target species were carefully analyzed. In addition, it was shown that optimal corridor designs could be altered to fit a landscape's opportunities and constraints.