Stand-level management of plantations to improve biodiversity values

As conservation reserves expand, the likelihood that they will capture areas degraded by previous land use increases. Ecological restoration of such areas will therefore play an increasing role in biodiversity conservation. On the New South Wales North Coast, recent expansion in the conservation estate has captured over 300 softwood and hardwood plantations, many with understoreys dominated by exotic weeds. Here we present an overview of the practices we have adopted in managing flooded gum (Eucalyptus grandis) plantations infested with lantana (Lantana camara) to enhance their biodiversity value. Experiments designed to overcome barriers limiting regeneration of native forest in conjunction with measurement of soil and plant responses yielded insights into the management of former timber plantations for biodiversity. Canonical Correspondence Analysis indicated that the level of canopy retention (or logging intensity) within sites consistently explained the greatest amount of variation in plant community composition (32–38% post-treatment). Thinning and burning stimulated regeneration of native species. Retained canopy cover was proportional to the richness or abundance of native woody shrubs, understorey trees and native perennial herbs, indicating that management intensity can be varied to promote a range of conservation values. A state-and-transition model summarising purported management actions and likely outcomes for these plantations is presented. This is the first time plantations have been managed solely for biodiversity. Logging income means that plantation restoration can be cost-neutral, and the positive influence of a cover crop of trees means that plantation management may generally be manipulated to promote biodiversity conservation.     

The isoprostanes: Novel prostaglandin-like products of the free radical-catalyzed peroxidation of arachidonic acid

The isoprostanes (IsoPs) are a unique series of prostaglandin-like compounds formed in vivo from the free radical-catalyzed peroxidation of arachidonic acid. This review summarizes our current knowledge regarding these compounds. Novel aspects of the biochemistry and bioactivity of IsoPs are detailed and methods by which these compounds are analyzed are discussed. A considerable portion of this review deals with the utility of measuring IsoPs as markers of oxidant injury in human diseases particularly in association with risk factors that predispose to atherosclerosis, a condition in which excessive oxidative stress has been causally implicated.     

Loss of Gadd45a does not modify the pulmonary response to oxidative stress

It is well established that exposure to high levels of oxygen (hyperoxia) injures and kills microvascular endothelial and alveolar type I epithelial cells. In contrast, significant death of airway and type II epithelial cells is not observed at mortality, suggesting that these cell types may express genes that protect against oxidative stress and damage. During a search for genes induced by hyperoxia, we previously reported that airway and alveolar type II epithelial cells uniquely express the growth arrest and DNA damage (Gadd)45a gene. Because Gadd45a has been implicated in protection against genotoxic stress, adult Gadd45a (+/+) and Gadd45a (-/-) mice were exposed to hyperoxia to investigate whether it protected epithelial cells against oxidative stress. During hyperoxia, Gadd45a deficiency did not affect loss of airway epithelial expression of Clara cell secretory protein or type II epithelial cell expression of pro-surfactant protein C. Likewise, Gadd45a deficiency did not alter recruitment of inflammatory cells, edema, or overall mortality. Consistent with Gadd45a not affecting the oxidative stress response, p21(Cip1/WAF1) and heme oxygenase-1 were comparably induced in Gadd45a (+/+) and Gadd45a (-/-) mice. Additionally, Gadd45a deficiency did not affect oxidative DNA damage or apoptosis as assessed by oxidized guanine and terminal deoxyneucleotidyl transferase-mediated dUTP nick-end labeling staining. Overexpression of Gadd45a in human lung adenocarcinoma cells did not affect viability or survival during exposure, whereas it was protective against UV-radiation. We conclude that increased tolerance of airway and type II epithelial cells to hyperoxia is not attributed solely to expression of Gadd45a.     

Guidelines for creating a food safety HACCP program in zoos or aquaria

The Hazard Analysis and Critical Control Point (HACCP) monitoring system has been used traditionally to increase quality control in human food production operations and there is pressure to implement it at the producer and purchaser levels of the food chain. Recently, the concept of HACCP monitoring has extended to food fed to domestic animals. Captive wildlife facilities, such as zoos and aquaria, would benefit from a well‐organized, food safety and nutritional monitoring system. Zoos and aquaria spend significant resources in time and money on maintaining the health of their animals; much of this energy is focused on disease prevention and adequate nutrition. The result of these combined efforts is the implementation of a HACCP program in zoo food management. Although zoo food handling standards have been implemented through the American Zoo and Aquarium Association (AZA) accreditation process, food borne disease outbreaks and malnutrition still exist. By implementing an organized approach to monitoring the quality of food delivered to the animals, the safety and nutritional value of the foods will increase, while decreasing the financial loss due to food waste and time spent caring for ill animals. This report provides a framework for implementing a HACCP program into the food preparation and handling system of zoos and aquaria. Zoo Biol 0:1–11, 2005. © 2005 Wiley‐Liss, Inc.     

Effect of serum concentration on the cytotoxicity of clay particles

Nanoparticle cytotoxicity testing based on in vitro methods frequently lack consistency. Even the inclusion of the commonly employed growth supplement, FCS (fetal calf serum), generates variable results. Thus, our object was to investigate the effect of FCS concentration on the cytotoxic behaviour of the unmodified nanoclay, Cloisite® Na⁺. Human monocytic U937 cells in medium supplemented with 5% FCS, 2.5% FCS or serum‐free medium were treated with 1 mg/ml Cloisite Na⁺. Cell growth in 2.5% FCS was significantly inhibited by Cloisite Na⁺ within 48 h, whereas little effect was seen with a supplement of 5% FCS. Without serum, cell growth was inhibited and Cloisite Na⁺ had a detrimental effect on these cells. In media supplemented with FCS, the nanoclays agglomerated together to form large bundles, whereas they were evenly dispersed throughout the medium in the absence of serum. Clay particles, therefore, have cytotoxic properties that may be linked to their dispersion pattern. These adverse effects seem to be masked by 5% FCS. Serum supplementation is an important consideration in the toxicological assessments of nanomaterials on cells, which needs to be addressed in the standardization of in vitro testing methods.