Predatory pollinator deception： Does the orchid mantis resemble a model species？

Cases of imperfect or non-model mimicry are common in plants and animals and challenge intuitive assumptions about the nature of directional selection on mimics. Many non-rewarding flower species do not mimic a particular species, but at- tract pollinators through ＇generalised food deception＇. Some predatory animals also attract pollinators by resembling flowers, perhaps the most well known, yet least well understood, is the orchid mantis Hymenopus coronatus. This praying mantis has been hypothesised to mimic a flower corolla and we have previously shown that it attracts and captures pollinating insects as prey. Predatory pollinator deception is relatively unstudied and whether this occurs through model mimicry or generalised food decep- tion in the orchid mantis is unknown. To test whether the orchid mantis mimics a specific model flower species we investigated similarities between its morphology and that of flowers in its natural habitat in peninsular Malaysia. Geometric morphometrics were used to compare the shape of mantis femoral lobes to flower petals. Physiological vision models were used to compare the colour of mantises and flowers from the perspective of bees, flies and birds. We did not find strong evidence for a specific model flower species for the orchid mantis. The mantis＇ colour and shape varied within the range of that exhibited by many flower pet- als rather than resembling one type in particular. We suggest that the orchid mantis resembles an average, or generalised flower-like stimulus. Thus predatory pollinator deception in the orchid mantis is likely to function as a form of generalised food deception, as opposed to model mimicry .     

Longevity of animals under reactive oxygen species stress and disease susceptibility due to global warming

The world is projected to experience an approximate doubling of atmospheric CO_2 concentration in the next decades. Rise in atmospheric CO_2 level as one of the most important reasons is expected to contribute to raise the mean global temperature 1.4 ℃-5.8 ℃ by that time. A survey from 128 countries speculates that global warming is primarily due to increase in atmospheric CO_2 level that is produced mainly by anthropogenic activities. Exposure of animals to high environmental temperatures is mostly accompanied by unwanted acceleration of certain biochemical pathways in their cells. One of such examples is augmentation in generation of reactive oxygen species(ROS) and subsequent increase in oxidation of lipids, proteins and nucleic acids by ROS. Increase in oxidation of biomolecules leads to a state called as oxidative stress(OS). Finally, the increase in OS condition induces abnormality in physiology of animals under elevated temperature. Exposure of animals to rise in habitat temperature is found to boost the metabolism of animals and a very strong and positive correlation exists between metabolism and levels of ROS and OS. Continuous induction of OS is negatively correlated with survivability and longevity and positively correlated with ageing in animals. Thus, it can be predicted that continuous exposure of animals to acute or gradual rise in habitat temperature due to global warming may induce OS, reduced survivability and longevity in animals in general and poikilotherms in particular. A positive correlation between metabolism and temperature in general and altered O_2 consumption at elevated temperature in particular could also increase the risk of experiencing OS in homeotherms. Effects of global warming on longevity of animals through increased risk of protein misfolding and disease susceptibility due to OS as the cause or effects or both also cannot be ignored. Therefore, understanding the physiological impacts of global warming in relation to longevity of animals will become very crucial challenge to biologists of the present millennium.     

Human-induced environmental changes influence habitat use by an ungulate over the long term

Habitat use and preferences may be subject to spatial and temporal changes. However, long-term studies of species-habitat relationships are the exception. In the prese nt research, I on g-term trends in habitat use by an alpine ungulate, the Tatra chamois Rupicapra rupicapra tatrica, were analyzed. We exami ned how envir on mental changes attributable to climate cha nge, removal of sheep, and habituation to hikers, which took place over the last half-century have changed the spatial distribution of animals. Data on the localities of groups sighted between 1957 and 2013 during autumnal population surveys were used to evaluate habitat associations: these were correlated with year, group size, population size, and climatic conditions. The results indicate that the Tatra chamois is tending, over the long term, to lower its altitude of occurrenee, reduce its average distance to hiking trails, and stay less often on slopes with a southerly aspect. These trends are in dependent of group size, population size, and the weather conditions prevailing during observations, though not for altitude, where increases in air temperature are related to finding chamois at higher elevations. The proportion of alpine meadows and slope in the places used by chamois is correlated with population size, while the proportion of areas with trees and/or shrubs is correlated with group size and air temperature, though long-term changes were not evident for these variables. To the best of our knowledge, this work is the first to document Iong-term trends in habitat use by ungulates. It shows that a species' ecology is influe need by huma n-in duced cha nges: abandonment of pasturage, high-mountain tourism, and climate changes, which constitute the most probable reasons for this aspect of behavioral evolution in the Tatra chamois.     

甘肃鼢鼠粪尿气味对侵占行为的影响

The Gansu zokor ( Myospalax cansus) is a solitary fossorial rodent, which inhabits its own tunnel system. The Gansu zokor are highly aggressive, and encounters between of two animals may end in the death or injury of one of them. In order to investigate the effect of fecaluria odor of the Gansu zokor on its invading behaviour, the behavioral methods were used to determine whether Gansu zokors use faeces to mark their own territorial boundaries and the effect on its excavation pattern. The results showed that when an intruder was introduced, the test animal almost always shifted its latrine location to the intruder‘s side. The Gansu zokor can detect the conspecific odor. In nonbreeding season, the odor of urine and faeces of Gansu zokors prolongs excavation of homosexual intruders and play a role in delaying conspecifics from entering the territory .     

Perception of illusory contours enhanced in motion

Object perception is one of the most important components of visual perception of human beings and mammalian animals. It is a most confusing problem on object perception that how we separate object from background and obtain the picture of the whole object. In many cases one object partly occludes the other one in natural world. When the brightness of the occluding object is the same as or similar to that of the background, though there is no difference between visual stimuli, we can still ret…     

A miniaturized assay to quantify effects of chemicals or physical stimuli upon locust activity

Solitary and gregarious locusts differ in many traits, such as body color, morphometrics and behavior. With respect to behavior, solitary animals shun each other, while gregarious animals seek each other＇s company, hence their crowding behavior. General activity, depending on the temperature, occurs throughout the day but is much lower in solitary locusts. Solitary locusts occasionally fly by night while gregarious locusts fly regularly during daytime （swarming）. In search of new assays to identify substances that control or modify aspects of （phase） behavior, we designed a simple activity assay, meant to complement existing behavioral measurement tools. The general activity is reflected in the number of wall hits, that is, the number of contacts between the locust and the vertical walls of a small arena. Using this single parameter we were able to quantify differences in total activity of both nymphs and adults of isolation-reared （solitary）, regrouped- and crowdreared （gregarious） locusts under different conditions. Furthermore, we demonstrate that there are inter- and intra-phase dependent differences in activities of 5th instar nymphs afar injections of the three different adipokinetic hormones.     

Rolling in Nature and Robotics： A Review

1 Introduction It is important to distinguish between a true rolling robot and one with just large wheels and a reaction point with the ground. It seems suitable to define a rolling robot as one that rolls on its entire outer surface rather than just external wheels and does not need to react any of the rotating torque against the ground. Thus they tend to be spherical or cylindrical in form and have a single axle (or no axle) and a completely active outer surface – i.e. a surface that is com…     

Rapid genomic changes in polyploid wheat and related species:implications for genome evolution and genetic improvement

A polyploid organism by possessing more than two sets of chromosomes from one species （autopolyploidy） or two or more species （allopolyploidy） is known to have evolutionary advantages. However, by what means a polyploid accommodates increased genetic dosage or divergent genomes （allopolyploidy） in one cell nucleus and cytoplasm constitutes an enormous challenge. Recent years have witnessed efforts and progress in exploring the possible mechanisms by which these seemingly intangible hurdles of polyploidy may be ameliorated or eventually overcome. In particular, the documentation of rapid and extensive non-Mendelian genetic and epigenetic changes that often accompany nascent polyploidy is revealing： the resulting non-additive and novel gene expression at global, regional and local levels, and timely restoration of meiotic chromosomal behavior towards bivalent pairing and disomic inheritance may ensure rapid establishment and stabilization as well as its long-term evolutionary success. Further elucidation on these novel mechanisms underpinning polyploidy will promote our understanding on fundamental issues in evolutionary biology and in our manipulation capacities in future genetic improvement of important crops that are currently polyploids in genomic constitution. This review is intended to provide an updated discussion on these interesting and important issues within the scope of a specific yet one of the most important plant groups--polyploid wheat and its related species.     

Hoarding habitat selection of squirrels (Sciurus vulgaris) in Liangshui Nature Reserve, China

This study was conducted during October 2003–April 2004 in the Liangshui National Nature Reserve of the Xiao Xing'an Mountains of Northeast China. Results showed that hoarding behavior of squirrels exhibited selectivity. The preference order of hoarding habitat selection of squirrels is as follows: original Korean pine forest, secondary natural fir forest, artificial fir forest, mix-conifer leaf forest, artificial fallen leaves pine forest, mix-conifer-broadleaf forest, mix-broadleaf forest birch forest, and artificial Korean pine forest. Compared with the existing results, using the cache spots as an index, the order of habitat selection changed, revealing that this research should include more factors, such as pilferage from other animals and secondary dispersal by the squirrels or other species. The Vanderploeg and Scavia selectivity indexes, Wi and Ei, were used to evaluate the use of microhabitat by squirrels in the original Korean pine forest. Results indicated that the squirrels exhibited a significant microhabitat utilization pattern: (1) Squirrels prefer to use the microhabitat in original Korean pine forest with high canopies, the medium shrubby density, and the medium stub density, where pilferage animals are few (Ei > 0.2); (2) Squirrels did not prefer to use the microhabitat in the original Korean pine forest with a low slope degree, high density of fallen logs and stumps, a high herbage coverage, and an abundance of pilferage animals (Ei < ?0.2), and they showed an aversion for a shaded slope (Ei = ?0.5368). The selectivity of microhabitat utilization for the hoarding behavior of squirrels plays an important role in determining the spatial pattern of Korean pine seedlings.     

Planting position and shade enhance native seedling performance in forest restoration for an endangered malagasy plant

The critically endangered tree Schizolaena tampoketsana is confined to a few diminished and degraded forest fragments on the Malagasy highlands. This habitat is vulnerable to loss due to frequent fires in the surrounding grassland that threaten to spread into the forest. One of these fragments is the focus a conservation project and here the managers aim to conserve S. tampoketsana by restoring its forest habitat to its former extent as evidenced by remnant woody plants. To inform this activity the survival and early-stage growth of seedlings of four locally native tree species were compared under contrasting conditions of proximity to the remaining forest and shade. After 12 months, seedlings of three species(Baronia taratana, Eugenia pluricymosa, Uapaca densifolia) survived better and experienced improved growth in height in grassland close to the existing forest rather than distant from it, and two survived better with shade rather than unshaded. A number of mechanisms could explain these results including reduced exposure to desiccating sunlight and winds and better soil and greater water availability close to the forest. The seedlings of one species(Nuxia capitata) survived well under all conditions. This study suggests that reforestation in these dry highlands is most feasible adjacent to remnant forest fragments and in microhabitats that minimize water loss, though young plants of some tree species may be capable of surviving in harsher conditions.     

Hoarding habitat selection of squirrels (Sciurus vulgaris) in Liangshui Nature Reserve, China

This study was conducted during October 2003–April 2004 in the Liangshui National Nature Reserve of the Xiao Xing'an Mountains of Northeast China. Results showed that hoarding behavior of squirrels exhibited selectivity. The preference order of hoarding habitat selection of squirrels is as follows: original Korean pine forest, secondary natural fir forest, artificial fir forest, mix-conifer leaf forest, artificial fallen leaves pine forest, mix-conifer-broadleaf forest, mix-broadleaf forest birch forest, and artificial Korean pine forest. Compared with the existing results, using the cache spots as an index, the order of habitat selection changed, revealing that this research should include more factors, such as pilferage from other animals and secondary dispersal by the squirrels or other species. The Vanderploeg and Scavia selectivity indexes, Wi and Ei, were used to evaluate the use of microhabitat by squirrels in the original Korean pine forest. Results indicated that the squirrels exhibited a significant microhabitat utilization pattern: (1) Squirrels prefer to use the microhabitat in original Korean pine forest with high canopies, the medium shrubby density, and the medium stub density, where pilferage animals are few (Ei > 0.2); (2) Squirrels did not prefer to use the microhabitat in the original Korean pine forest with a low slope degree, high density of fallen logs and stumps, a high herbage coverage, and an abundance of pilferage animals (Ei < ?0.2), and they showed an aversion for a shaded slope (Ei = ?0.5368). The selectivity of microhabitat utilization for the hoarding behavior of squirrels plays an important role in determining the spatial pattern of Korean pine seedlings.     

Animal venom studies: Current benefits and future developments

Poisonous organisms are represented in many taxa, including kingdom Animalia. During evolution, animals have developed special organs for production and injection of venoms. Animal venoms are complex mixtures, compositions of which depend on species producing venom. The most known and studied poisonous terrestrial animals are snakes, scorpions and spiders. Among marine animals, these are jellyfishes, anemones and cone snails. The toxic substances in the venom ofthese animals are mainly of protein and peptide origin. Recent studies have indicated that the single venom may contain up to several hundred different components producing diverse physiological effects. Bites or stings by certain poisonous species result in severe envenomations leading in some cases to death. This raises the problem of bite treatment. The most effective treatment so far is the application of antivenoms. To enhance the effectiveness of such treatments, the knowledge of venom composition is needed. On the other hand, venoms contain substances with unique biological properties, which can be used both in basic science and in clinical applications. The best example of toxin application in basic science is α-bungarotoxin the discovery of which made a big impact on the studies of nicotinic acetylcholine receptor. Today compositions of venom from many species have already been examined. Based on these data, one can conclude that venoms contain a large number of individual components belonging to a limited number of structural types. Often minor changes in the amino acid sequence give rise to new biological properties. Change in the living conditions of poisonous animals lead to alterations in the composition of venoms resulting in appearance of new toxins. At the same time introduction of new methods of proteomics and genomics lead to discoveries of new compounds, which may serve as research tools or as templates for the development of novel drugs. The application of these sensitive and comprehensive methods allows studying either of venoms available in tiny amounts or of low abundant components in already known venoms.     

Evaluating the Importance of Environmental Variables on Spatial Distribution of Caspian cobra Naja oxiana(Eichwald, 1831) in Iran

Over recent years, the population of Caspian cobra Naja oxiana has declined in its distribution range in Iran due to habitat destruction and overhunting. Consequently, their small and isolated populations in fragmented landscapes are facing genetic and demographic threats. Evaluating the spatial distribution pattern of Naja oxiana, identifying core habitat patches and improving landscape connectivity among the patches have a significant role in the long-term survival of the species. This study predicts the spatial distribution map of the Caspian cobra considering the factors affecting the predictive power of the distribution models, including sampling bias in presence points, correct selection of background locations, and input model parameters. The sampling bias in presence points was removed using spatial filtering. Several models were run using 19 environmental variables that eventually led to the selection of the effective habitat variables and best MaxEnt distribution model. We also used an ensemble model(EM) of habitat suitability methods to predict the potential habitats of the species. Topographical roughness, shrublands, average annual precipitation, and sparse rangeland with a density of ≤ 20% had the most effect on the spatial distribution of Caspian cobra. The evaluation of models confirmed that the EM has more predictive performance than MaxEnt in predicting the distribution of Naja oxiana.     

GIS-based seasonal pattern of Rhinopithecus roxellana’s habitat selection in Shennongjia Reserve, Central China

Rhinopithecus roxellana’s habitat condition is directly related to its long-term survival and reproduction. Research, with large-scale, on R. roxellana’s habitat selection of seasonal changes is conducive to the protection and construction of its habitat, and it is essential protecting the rare species. Our research is based on the results of previous studies in biological and behavioral ecological field. With the support of GIS and RS technology, we conducted a lot of field investigations. In addition, we also took R. roxellana’s selection bias of seven kinds of ecological factors into consideration. Through the above efforts, we got a selection intensity distribution layer about R. roxellana’s habitat selection of seasonal changes. Our study shows that in spring, the area of weak intensity is 1507.96 hm² while less weak area is 33868.72 hm². The strong intensity area is 266 hm² while the less strong area is 36818.84 hm².
In summer, the area of weak intensity is 4683.4 hm² while less weak area is 28392.4 hm². The strong intensity area is 4078.52 hm² while the less strong area is 35307.2 hm².
In autumn, the area of weak intensity is 1972.08 hm² while less weak area is 33254.72 hm². The strong intensity area is 1516.84 hm² while the less strong area is 35717.88 hm².
In winter, the area of weak intensity is 542.76 hm² while less weak area is 28230.84 hm². The strong intensity area is 392.44 hm² while the less strong area is 43295.48 hm².
The results show that the most forestry areas of the Shennongjia Mt. lie in strong intensity area and these areas provides optimal habitat for the Snub-nosed Monkey.
The distribution layer analyses show that eastern part of the Shennongjia area is coincidence with the current natural distribution of the Snub-nosed Monkey, whereas north-western, south-western and southern part of the area is located in the weak intensity areas and is unfit for the Snub-nosed Monkey. In the central part, the strong intensity areas are fragmented by the highways and no Snub-nosed Monkey is found in this highly disturbed area. However, it is probably a potential habitat for the Snub-nosed Monkey.
Survival and reproduction of the Snub-nosed Monkey was ensured by large and continuous habitat in the eastern part of the Shennongjia Mt. Much effort is needed to intensify the connection of the fragmented central area of the Shennongjia Mt.     

Did maize domestication and early spread mediate the population genetics of corn leafhopper?

Investigating how crop domestication and early farming mediated crop attributes, distributions, and interactions with antagonists may shed light on today's agricultural pest problems. Crop domestication generally involved artificial selection for traits desirable to early farmers, for example, in creased productivity or yield, and enhanced qualities, though invariably it altered the interactions between crops and insects, and expanded the geographical ranges of crops. Thus, some studies suggest that with crop domestication and spread, insect populations on wild crop ancestors gave rise to pestiferous insect populations on crops. Here, we addressed whether the emergence of corn leafhopper (Dalbulus ma id is) as an agricultural pest may be associated with domestication and early spread of maize (Zea mays mays). We used AFLP markers and mitochondrial COI sequences to assess population genetic structuring and haplotype relationships among corn leafhopper samples from maize and its wild relative Zea diploperennis from multiple locations in Mexico and Argentina. We uncovered seven corn leafhopper haplotypes contained within two haplogroups, one haplogroup containing haplotypes associated with maize and the other containing haplotypes associated with Z. diploperennis in a mountainous habitat. Within the first haplogroup, one haplotype was predominant across Mexican locations, and another across Argentinean locations;both were considered pestiferous. We suggested that the divergence times of the maize-associated haplogroup and of the "pestiferous" haplotypes are correlated with the chronology of maize spread following its domestication. Overall, our results support a hypothesis positing that maize domestication favored corn leafhopper genotypes preadapted for exploiting maize so that they became pestiferous, and that with the geographical expansi on of maize farming, corn leafhopper colonized Z. diploperennis, a host exclusive to secluded habitats that serves as a refuge for archaic corn leafhopper genotypic diversity. Broadly, our results help explain the extents to which crop domestication and early spread may have mediated the emergence of today's agricultural pests.     

GIS-based seasonal pattern of Rhinopithecus roxellana’s habitat selection in Shennongjia Reserve, Central China

Rhinopithecus roxellana’s habitat condition is directly related to its long-term survival and reproduction. Research, with large-scale, on R. roxellana’s habitat selection of seasonal changes is conducive to the protection and construction of its habitat, and it is essential protecting the rare species. Our research is based on the results of previous studies in biological and behavioral ecological field. With the support of GIS and RS technology, we conducted a lot of field investigations. In addition, we also took R. roxellana’s selection bias of seven kinds of ecological factors into consideration. Through the above efforts, we got a selection intensity distribution layer about R. roxellana’s habitat selection of seasonal changes. Our study shows that in spring, the area of weak intensity is 1507.96 hm² while less weak area is 33868.72 hm². The strong intensity area is 266 hm² while the less strong area is 36818.84 hm².
In summer, the area of weak intensity is 4683.4 hm² while less weak area is 28392.4 hm². The strong intensity area is 4078.52 hm² while the less strong area is 35307.2 hm².
In autumn, the area of weak intensity is 1972.08 hm² while less weak area is 33254.72 hm². The strong intensity area is 1516.84 hm² while the less strong area is 35717.88 hm².
In winter, the area of weak intensity is 542.76 hm² while less weak area is 28230.84 hm². The strong intensity area is 392.44 hm² while the less strong area is 43295.48 hm².
The results show that the most forestry areas of the Shennongjia Mt. lie in strong intensity area and these areas provides optimal habitat for the Snub-nosed Monkey.
The distribution layer analyses show that eastern part of the Shennongjia area is coincidence with the current natural distribution of the Snub-nosed Monkey, whereas north-western, south-western and southern part of the area is located in the weak intensity areas and is unfit for the Snub-nosed Monkey. In the central part, the strong intensity areas are fragmented by the highways and no Snub-nosed Monkey is found in this highly disturbed area. However, it is probably a potential habitat for the Snub-nosed Monkey.
Survival and reproduction of the Snub-nosed Monkey was ensured by large and continuous habitat in the eastern part of the Shennongjia Mt. Much effort is needed to intensify the connection of the fragmented central area of the Shennongjia Mt.     

Animal personalities and their implications for complex signaling

Animal personalities have been a major focus of behavioral ecology over the past decade. Consistent individual dif ferences in behavior have been found across taxa, and have been shown to influence a range of ecological processes. The role of personalities in sexual selection has been considered, and examples exist that show selection for personality traits with both assortative and disassortative mating patterns between personality types. One overlooked aspect of the personality and sexual se lection literature is the potential for personalitysignaling interactions, specifically with complex signaling. Complex signaling is a diverse topic in itself, and in short, consists of multiple signals within one or more modalities that interact to elicit a receiver response. Research into complex signaling has been thorough, although at times studies discover complex signaling systems that fail to fit into one of the existing hypotheses in the literature. Here, we argue that personalities may interact with complex signal ing, which should be considered by researchers of both personality and sexual selection and communication. We describe several ways in which personalitycomplex signaling interactions could affect both the signaler and receiver, and the way in which they may drive personalityspecific signals as well as receiver preferences. Finally, we discuss how considering personality in com plex signaling studies may inform theory as well as improve the ability of researchers to accurately describe its function.     

山西五台山地区褐马鸡的再引入

Brown eared-pheasant Crossoptilon mantchuricum is endemic to China, and mainly occurs in Luliang Mountains of Shanxi, Xiaowntai of Hebei and Huanglong of Shaanxi. Reintroduction of Brown eared pheasant was carried out from April to December in 2000. According to the criterions of release site selection in Guidelines for Reintroductions of IUCN, and habitat selection of Brown eared pheasant, Kuantan forestry in Wutaishan Mountains of Shanxi Province was selected as the release site. Of the 8 released individuals, 5 wild individuals were captured in winter in Luyashan Nature Reserve of Shanxi Province, and 3 were offsprings of captive-reared individuals. Transmitters were attached when the 8 individuals were released. Overall, 6 individuals survived for at least 1 month, and the longest time for survival was 155 days, except that one was confirmed as having been killed by a raptor on the second day and one was lost on the eighth day after release. All moved away from the release site after release and established stable home ranges in different sites after 10 days, respectively. In early May, the individuals again dispersed to establish new home ranges. The wandering distance and days of the captive individuals were longer and the home range size were larger than that of the wild birds,which resulted from the weak adaptability to new habitat for the captive individuals, such as recognizing and fetching food. For wild individuals, the second wandering distance was longer than the first. We believe the difference was related to looking for partners. After wandering, individuals established stable home ranges in different sites [Acta Zoologica Sinica 50 (1): 126-132, 2004].     

Foraging site recursion by forest elephants Elephas maximus borneensis

Recursion by herbivores is the repeated use of the same site or plants. Recursion by wild animals is rarely investigated but may be ubiquitous. Optimal foraging theory predicts site recursion as a function of the quality of the site, extent of its last use, and time since its last use because these influence site resource status and recovery. We used GPS collars, behaviour and site sampling to investigate recursion to foraging sites for two elephant Elephas maximus borneensis herds in the Lower Kinabatangan Wildlife Sanctuary, Borneo, over a 12 month period. Recursion occurred to 48 out of 87 foraging sites and was most common within 48 hours or between 151-250 days, indicating two different types ofrecursion. Recursion was more likely to occur if the site had previously been occupied for longer. Moreover, the time spent at a site at recursion was the same as the time spent at the site on the first occasion. The number of days that had passed between the first visit and recursion was also positively correlated with how much time was spent at the site at recursion. Habitat type also influenced the intensity of site-use, with more time spent at recursion within riverine/open grass areas along forest margins compared to other habitat types. Recursion is a common behaviour used by the elephants and its pattern suggests it may be a foraging strategy for revisiting areas of greater value. The qualities of recursion sites might usefully be incorporated into landscape management strategies for elephant conservation in the area [Current Zoology 60 （4）： 551-559, 2014].     

Identification,expression, and characterization of the highly conserved D-xylose isomerase in animals

D-xylose is a necessary sugar for animals. The xylanase from a mollusk, Ampullaria crossean, was previously reported by our laboratory. This xylanase can degrade the xylan into D-xylose. But there is still a gap in our knowledge on its metabolic pathway. The question is how does the xylose enter the pentose pathway？ With the help of genomic databases and bioinformatic tools, we found that some animals, such as bacteria, have a highly conserved D-xylose isomerase （EC 5.3.1.5）. The xyiose isomerase from a sea squirt, Ciona intestinali, was heterogeneously expressed in Escherichia coli and purified to confirm its function. The recombinant enzyme had good thermal stability in the presence of Mg^2＋. At the optimum temperature and optimum pH environment, its specific activity on D-xylose was 0.331 μmol/mg/min. This enzyme exists broadly in many animals, but it disappeared in the genome of Amphibia-like Xenopus laevis. Its sequence was highly conserved. The xylose isomerases from animals are very interesting proteins for the study of evolution.