Evaluation of CHROMagar™ StrepB agar, an aerobic chromogenic medium for prepartum vaginal/rectal Group B Streptococcus screening

An aerobic chromogenic medium, CHROMagar™ StrepB agar, designed for isolation of group B Streptococci, was evaluated on 285 prepartum vaginal/rectal swabs from pregnant women. After overnight enrichment in Todd-Hewitt broth containing 15 μg/ml nalidixic acid and 10 μg/ml colistin, sensitivities were respectively 79% on day 1 and 92% on day 2, and significantly higher than those achieved by blood agar (40% and 58%) and colimycin-nalidixic-acid agar (82% on day 2).     

Evaluation of CHROMagar™ StrepB: A new chromogenic agar medium for aerobic detection of Group B Streptococci in perinatal samples

A selective and chromogenic medium, the CHROMagar™ StrepB agar (CHROM-B) designed for aerobic isolation of Group B Streptococci (GBS) in pregnancy-related specimens, was evaluated in a two-Phase study. CHROM-B was evaluated against CPS3 during the first Phase and against Granada afterwards. It was compared to blood agar plates (COH) and to colimycin nalidixic agar plates (CNA) over both Phases. The study which included 1356 samples, yielded 124 GBS. CHROM-B was significantly more sensitive than COH (76.6% vs 53.2% on d1 and 92.7% vs 64.5% on d2; p < 0.001 for both). CHROM-B yielded positive results sooner than CNA. CPS3 under-performed, partly because of microbiota overgrowth and partly because it did not produce a single and unique colour from the GBS colonies. CHROM-B produced its unique GBS-expected colour sooner than Granada yielding a significantly sooner result for 10% (6/60; p < 0.025). Every 124 GBS could grow typical colonies on CHROM-B and False Negatives were only due to paucimicrobial samples. Granada failed to produce the expected colour from one non-haemolytic GBS. We conclude that CHROMagar™ StrepB performed significantly better, irrespective of the haemolytic properties of GBS strains, and significantly sooner than COH, CNA, CPS3 and Granada.     

Confronting the Paradox of Enrichment to the Metacommunity Perspective

Resource enrichment can potentially destabilize predator-prey dynamics. This phenomenon historically referred as the "paradox of enrichment" has mostly been explored in spatially homogenous environments. However, many predator-prey communities exchange organisms within spatially heterogeneous networks called metacommunities. This heterogeneity can result from uneven distribution of resources among communities and thus can lead to the spreading of local enrichment within metacommunities. Here, we adapted the original Rosenzweig-MacArthur predator-prey model, built to study the paradox of enrichment, to investigate the effect of regional enrichment and of its spatial distribution on predator-prey dynamics in metacommunities. We found that the potential for destabilization was depending on the connectivity among communities and the spatial distribution of enrichment. In one hand, we found that at low dispersal regional enrichment led to the destabilization of predator-prey dynamics. This destabilizing effect was more pronounced when the enrichment was uneven among communities. In the other hand, we found that high dispersal could stabilize the predator-prey dynamics when the enrichment was spatially heterogeneous. Our results illustrate that the destabilizing effect of enrichment can be dampened when the spatial scale of resource enrichment is lower than that of organismss movements (heterogeneous enrichment). From a conservation perspective, our results illustrate that spatial heterogeneity could decrease the regional extinction risk of species involved in specialized trophic interactions. From the perspective of biological control, our results show that the heterogeneous distribution of pest resource could favor or dampen outbreaks of pests and of their natural enemies, depending on the spatial scale of heterogeneity.     

不同丰容方式对圈养成年山魈行为影响的试验

于2011年对成都动物园饲养的8只成年圈养山魈进行3种食物丰容、2种环境丰容及5种食物与环境丰容试验,考察不同形式丰容方式对圈养山魈行为的影响.结果表明,第一期丰容试验(B)后,山魈的休息行为、运动行为和玩耍行为增加极显著(P＜0.01),而交往行为和取食行为减少极显著(P＜0.01);第二期丰容(D)后,休息行为减少极显著,交往行为增加显著,运动行为、采食行为和玩耍行为增加极显著.山魈对纯轮胎丰容方式的接触次数最少,而对食物丰容方式接触次数更多.有两种丰容方式(纯轮胎丰容和纯轮胎+纯麻袋丰容)仅持续很短的时间即失去作用,其余的丰容方式一般在第8d出现兴趣下降的现象,因此建议每种丰容方式的持续使用时间不超过8d.     

Maximizing the effectiveness of environmental enrichment: Suggestions from the experimental analysis of behavior

Environmental enrichment programs provide benefits to both captive animals and the facilities that house them, but cost time and resources to design, implement, and maintain. As yet, there have been few theoretically based guidelines to assist animal care staff in establishing cost-efficient enrichment methods that both elicit the desired behavioral changes and maintain their success over time. We describe several well-studied principles from the field of experimental analysis of behavior, including intrinsic reinforcement, extrinsic reinforcement, habituation, extinction, and schedules of reinforcement that could be very useful for evaluating the short- and long-term effectiveness of enrichment. We use this theoretical framework to generate testable hypotheses and provide examples of enrichment studies relevant to our predictions. In particular, we suggest that enrichment devices that offer extrinsic reinforcement (food, social access, etc. as a result of performing behaviors) should produce greater and more prolonged changes in behavior than devices that rely on the behavior itself being reinforcing to the animal. For techniques that provide no extrinsic reinforcement, using stimuli that are novel, are more different from the environment, have been withheld or altered in some way, or are presented less frequently may help reduce habituation. For techniques that provide extrinsic reinforcement, making reinforcement more difficult to obtain and providing more or higher quality reinforcers may increase the long-term success of the enrichment program. In addition, enrichment may be more effective if animal care staff avoid continuously reinforcing behaviors after they are established, enriching immediately after feeding, and exposing animals to enrichment when reinforcement is no longer available. While the current enrichment literature supports the application of behavior analytic theory, empirical evaluation of many of our predictions is still needed.     

Enrichment Disequilibrium: A novel approach for measuring the degree of enrichment after gene enrichment test

Motivation: Commonly used gene enrichment analysis methods, such as Hypergeometric distribution, play an important role in the functional analysis of interesting gene lists. But the statistical significance obtained by these methods only represents the probability of error that is involved in accepting enrichment, and is not suitable to evaluate the degree of enrichment. Although there have been some methods to measure the enrichment degrees, such as relative enrichment factor, new methods are still needed to meet the requirements for comparing the degree of enrichment. Results: We developed a novel method, Enrichment Disequilibrium (ED), to measure the degree of enrichment. Enrichment equilibrium means that the interesting gene set and the known functional gene set (such as a KEGG pathway) are independent (i.e. random association). ED is defined as the degree of non-independence. Compared with the relative enrichment factor, ED has a clearer biological meaning, is a standardized indicator, and has a symmetrical interval (range from -1 to +1). It is more suitable to measure the enrichment degree. For an interesting gene set, researchers can obtain some significant functional gene sets by traditional enrichment test. Then using ED, they can compare the degree of enrichment among these significant gene sets, and prioritize them.     

A rapid and sensitive method for the detection of Yersinia enterocolitica strains from clinical samples

AIMS: To compare three culture methods to detect Yersinia enterocolitica from oral or rectal swabs from experimentally infected pigs. METHODS AND RESULTS: The three methods used were: direct plating on Cefsulodin-Irgasan-Novobiocin (CIN) agar, cold enrichment in phosphate buffered saline (PBS) followed by plating on CIN agar and selective enrichment with Luria-Bertani-Bile Salts Irgasan (LB-BSI) followed by plating on CIN agar. Selective enrichment with LB-BSI produced the highest recovery rate (63%), when compared with cold enrichment (52%) and plating on CIN agar alone (43%). Selective enrichment with LB-BSI was significantly (P < 0.02) more sensitive than direct plating on CIN agar and more sensitive than cold enrichment (P < 0.1). CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: Selective enrichment with LB-BSI was more sensitive than the widely accepted method of cold enrichment and it reduced the time required for detection of Y. enterocolitica by three weeks. Selective enrichment with LB-BSI was also compatible with a multiplex PCR technique.     

Imperfect optimal foraging and the paradox of enrichment

We show that the paradox of enrichment can be theoretically resolved in a flexible predator–prey system in which the predator practices imperfect optimal foraging. A previous study showed that perfect optimal foraging can mitigate increases in the amplitude of population oscillations associated with enrichment, but it did not show a stabilization pattern. Our results show that imperfect optimal foraging can stabilize the system and resolve the paradox of enrichment under nonequilibrium dynamics. Furthermore, the degree of stabilization with enrichment was stronger when the imperfection of optimal foraging was larger.     

On the progressive enrichment of the oxygen isotopic composition of water along a leaf

A model has been derived for the enrichment of heavy isotopes of water in leaves, including progressive enrichment along the leaf. In the model, lighter water is preferentially transpired leaving heavier water to diffuse back into the xylem and be carried further along the leaf. For this pattern to be pronounced, the ratio of advection to diffusion (Péclet number) has to be large in the longitudinal direction, and small in the radial direction. The progressive enrichment along the xylem is less than that occurring at the sites of evaporation in the mesophyll, depending on the isolation afforded by the radial Péclet number. There is an upper bound on enrichment, and effects of ground tissue associated with major veins are included. When transpiration rate is spatially nonuniform, averaging of enrichment occurs more naturally with transpiration weighting than with area‐based weighting. This gives zero average enrichment of transpired water, the modified Craig–Gordon equation for average enrichment at the sites of evaporation and the Farquhar and Lloyd (In Stable Isotopes and Plant Carbon‐Water Relations, pp. 47–70. Academic Press, New York, USA, 1993) prediction for mesophyll water. Earlier results on the isotopic composition of evolved oxygen and of retro‐diffused carbon dioxide are preserved if these processes vary in parallel with transpiration rate. Parallel variation should be indicated approximately by uniform carbon isotope discrimination across the leaf.     

On the progressive enrichment of the oxygen isotopic composition of water along a leaf

A model has been derived for the enrichment of heavy isotopes of water in leaves, including progressive enrichment along the leaf. In the model, lighter water is preferentially transpired leaving heavier water to diffuse back into the xylem and be carried further along the leaf. For this pattern to be pronounced, the ratio of advection to diffusion (Péclet number) has to be large in the longitudinal direction, and small in the radial direction. The progressive enrichment along the xylem is less than that occurring at the sites of evaporation in the mesophyll, depending on the isolation afforded by the radial Péclet number. There is an upper bound on enrichment, and effects of ground tissue associated with major veins are included. When transpiration rate is spatially nonuniform, averaging of enrichment occurs more naturally with transpiration weighting than with area-based weighting. This gives zero average enrichment of transpired water, the modified Craig-Gordon equation for average enrichment at the sites of evaporation and the Farquhar and Lloyd (In Stable Isotopes and Plant Carbon-Water Relations, pp. 47-70. Academic Press, New York, USA, 1993) prediction for mesophyll water. Earlier results on the isotopic composition of evolved oxygen and of retro-diffused carbon dioxide are preserved if these processes vary in parallel with transpiration rate. Parallel variation should be indicated approximately by uniform carbon isotope discrimination across the leaf.     

Enrichment and primate centers: closing the gap between research and practice

A wealth of published research is available to guide environmental enrichment programs for nonhuman primates, but common practice may not consistently correspond to research findings. A 2003 survey to quantify common practice queried individuals overseeing enrichment programs about (a) social, feeding, structural, and manipulable enrichment; (b) human interaction and training; (c) general program administration; (d) the role of the institutional animal care and use committee (IACUC) in the enrichment program; and (e) the impetus for recent programmatic changes. Returned surveys provided information on the management of 35,863 primates and found social housing significantly more constrained than inanimate enrichment. Survey results suggest that social housing of macaques has not increased significantly over the past decade. The most commonly mentioned constraints related to research protocols. Facilities with thorough IACUC reviews of enrichment issues provided social housing for a significantly larger proportion of primates in biomedical research studies than did those with rare IACUC reviews. IACUC reviews prompted program enhancements much less often than did regulatory or accreditation inspections. These results suggest IACUC review is an underutilized mechanism for improving enrichment programs.     

Enrichment and Primate Centers: Closing the Gap Between Research and Practice

A wealth of published research is available to guide environmental enrichment programs for nonhuman primates, but common practice may not consistently correspond to research findings. A 2003 survey to quantify common practice queried individuals overseeing enrichment programs about (a) social, feeding, structural, and manipulable enrichment; (b) human interaction and training; (c) general program administration; (d) the role of the institutional animal care and use committee (IACUC) in the enrichment program; and (e) the impetus for recent programmatic changes. Returned surveys provided information on the management of 35,863 primates and found social housing significantly more constrained than inanimate enrichment. Survey results suggest that social housing of macaques has not increased significantly over the past decade. The most commonly mentioned constraints related to research protocols. Facilities with thorough IACUC reviews of enrichment issues provided social housing for a significantly larger proportion of primates in biomedical research studies than did those with rare IACUC reviews. IACUC reviews prompted program enhancements much less often than did regulatory or accreditation inspections. These results suggest IACUC review is an underutilized mechanism for improving enrichment programs.     

磷酸化蛋白质组学研究中磷酸化肽段富集与分离方法研究进展

对磷酸化蛋白质组（phosphoproteome）进行系统深入的研究依赖于高重复性和特异性的磷酸化肽段富集与分离方法。目前发展了多种不同原理的磷酸化肽段富集方法,它们往往具有不同的选择性和特异性,因此,根据不同的研究目的选择最适合的富集方法显得尤为重要。本文综述了基于亲和色谱法（affinity chromatography）、免疫沉淀法（immunoprecipitation）、化学衍生法（chemical derivatization）、色谱法（chromatography）和其他新发展方法的磷酸化肽段富集方法,详细介绍了各自的优缺点及相关的优化与改进策略。此外,还简单介绍了磷酸化肽段富集与预分方法的不同组合的研究进展。     

Behavioral and physiologic responses to environmental enrichment in the maned wolf (Chrysocyon brachyurus)

The ex situ population of maned wolves is not self‐sustaining due to poor reproduction, caused primarily by parental incompetence. Studies have shown that environmental enrichment can promote natural parental behaviors in zoo animals. The objective of this study was to determine the effects of environmental enrichment on behavioral and physiological responses of maned wolves. During an 8‐week experimental period, daily behavior observations and fecal sample collection were conducted on four adult wolves (2.2) individually housed in environments without enrichment. After 2 weeks, the wolves were chronologically provided with 2‐week intervals of hiding dead mice around the exhibit, no enrichment, and introduction of boomer balls. Responses of the wolves to enrichment were assessed based on activity levels and exploratory rates, as well as the level of corticoid metabolites in fecal samples collected daily throughout the study period. Providing wolves with environmental enrichment significantly increased exploratory behaviors (P<0.05), especially when mice were hidden in the enclosure. Fecal corticoid concentrations were increased during periods of enrichment in males (P<0.05), but not in females. Overall, there were no correlations between behavioral responses to enrichment and fecal corticoid levels. Behavioral results suggest that environmental enrichment elicits positive effects on the behavior of captive maned wolves. There is evidence suggesting that providing animals with ability to forage for food is a more effective enrichment strategy than introducing objects. There is need for a longer term study to determine the impact of environmental enrichment in this species. Zoo Biol 26:331–343, 2007. © 2007 Wiley‐Liss, Inc.     

Sensitivity and Specificity of Different Methods for the Isolation of Salmonella from Pigs

Three different selective enrichment media, Rappaport-Vassiliadis broth (RV), selenite broth (SB) and Müller-Kauffmann tetrathionate broth (MKTB), in combination with plating on modified brilliant green agar (BGA), were compared for the isolation of Salmonella from samples of pig feces. These conventional methods were also compared with a new ELISA kit in conjunction with RV and SB enrichment. Of the conventional methods, enrichment in RV had a higher sensitivity and selectivity than SB and MKTB. Recovery of S. typhimurium from MKTB was significantly poorer than recovery of other serotypes. The combination of RV enrichment and ELISA was as good as the conventional method involving RV enrichment, with a similar high sensitivity and specificity.     

A resolution of the paradox of enrichment

Theoretical studies have shown a paradoxical destabilizing response of predator-prey ecosystems to enrichment, but there is the gap between the intuitive view of nature and this theoretical prediction. We studied a minimal predator-prey system (a two predator-two prey system) in which the paradox of enrichment pattern can vanish; the destabilization with enrichment is reversed, leading to stabilization (a decrease in the amplitude of oscillation of population densities). For resolution of the paradox, two conditions must be met: (1) the same prey species must be preferred as a dietary item by both predator species, creating the potential for high exploitative competition between the predator species, and (2), while both predators are assumed to select their diet in accordance with optimal diet utilization theory, one predator must be a specialist and the other a generalist. In this system, the presence of a less profitable prey species can cause the increase in population oscillation amplitudes associated with increasing enrichment to be suppressed via the optimal diet utilization of the generalist predator. The resulting stabilization is explained by the mitigating effect of the less profitable prey showing better population growth with increasing enrichment on the destabilization underlying the specialist predator and prey relation, thus resolving the paradox of enrichment.     

Bobcat (Lynx rufus) breeding in captivity: the importance of environmental enrichment

Environmental enrichment is an improvement in the biological functioning of nonhuman animals in captivity resulting from modifications to their environment; however, specifying appropriate and practical measures of enrichment is problematic. This study analyzes the behavior of 4 bobcats (Lynx rufus) in the Jerez Zoo before and after the application of a global program of environmental enrichment that included (a) changes in the size and complexity of their installations, (b) the introduction of new objects into compounds, (c) changes in diet, and (d) modifications in the grouping of animals. A factorial correspondence analysis showed a highly significant relationship among individual animals, behavior, and experimental design. Behaviors such as locomotion, repeated pacing, vigilance, and grooming more often occurred before enrichment, whereas exploratory and food behaviors were more often associated with the enrichment phase. After the implementation of the enrichment program, the bobcats bred successfully for the first time since their arrival in the zoo.     

A meta‐analysis of the effects of nutrient enrichment on litter decomposition in streams

The trophic state of many streams is likely to deteriorate in the future due to the continuing increase in human‐induced nutrient availability. Therefore, it is of fundamental importance to understand how nutrient enrichment affects plant litter decomposition, a key ecosystem‐level process in forest streams. Here, we present a meta‐analysis of 99 studies published between 1970 and 2012 that reported the effects of nutrient enrichment on litter decomposition in running waters. When considering the entire database, which consisted of 840 case studies, nutrient enrichment stimulated litter decomposition rate by approximately 50%. The stimulation was higher when the background nutrient concentrations were low and the magnitude of the nutrient enrichment was high, suggesting that oligotrophic streams are most vulnerable to nutrient enrichment. The magnitude of the nutrient‐enrichment effect on litter decomposition was higher in the laboratory than in the field experiments, suggesting that laboratory experiments overestimate the effect and their results should be interpreted with caution. Among field experiments, effects of nutrient enrichment were smaller in the correlative than in the manipulative experiments since in the former the effects of nutrient enrichment on litter decomposition were likely confounded by other environmental factors, e.g. pollutants other than nutrients commonly found in streams impacted by human activity. However, primary studies addressing the effect of multiple stressors on litter decomposition are still few and thus it was not possible to consider the interaction between factors in this review. In field manipulative experiments, the effect of nutrient enrichment on litter decomposition depended on the scale at which the nutrients were added: stream reach > streamside channel > litter bag. This may have resulted from a more uniform and continuous exposure of microbes and detritivores to nutrient enrichment at the stream‐reach scale. By contrast, nutrient enrichment at the litter‐bag scale, often by using diffusing substrates, does not provide uniform controllable nutrient release at either temporal or spatial scales, suggesting that this approach should be abandoned. In field manipulative experiments, the addition of both nitrogen (N) and phosphorus (P) resulted in stronger stimulation of litter decomposition than the addition of N or P alone, suggesting that there might be nutrient co‐limitation of decomposition in streams. The magnitude of the nutrient‐enrichment effect on litter decomposition was higher for wood than for leaves, and for low‐quality than for high‐quality leaves. The effect of nutrient enrichment on litter decomposition may also depend on climate. The tendency for larger effect size in colder regions suggests that patterns of biogeography of invertebrate decomposers may be modulating the effect of nutrient enrichment on litter decomposition. Although studies in temperate environments were overrepresented in our database, our meta‐analysis suggests that the effect of nutrient enrichment might be strongest in cold oligotrophic streams that depend on low‐quality plant litter inputs.     

Environmental enrichment for laboratory rodents: animal welfare and the methods of science

Because of the difficulty of' establishing objective measures of laboratory rodents' psychological well-being, developing environmental enrichment programs that are actually beneficial to rodents destined to participate in laboratory research is particularly challenging. Many studies of effects of environmental complexity, social housing, and increases in cage size suggest that professional judgments as to the impact of diverse types of environmental enrichment on rodent welfare are not a reliable basis for evaluating the outcomes of enrichment programs for laboratory rodents. Successful enrichment programs will vary from one rodent species to another, between sexes, as well as between age classes. There is a need for objective, measurable goals for proposed environmental enrichment programs for rodents, as well a s for empirical investigations of the beneficial and detrimental consequences of proposed environmental manipulations.