The patterns of biodiversity changes in cities are now fairly well established, although diversity changes in temperate cities are much better studied than cities in other climate zones. Generally, plant species richness often increases in cities due to importation of exotic species, whereas animal species richness declines. Abundances of some groups, especially birds and arthropods, often increase in urban areas despite declines in species richness. Although several models have been proposed for biodiversity change, the processes underlying the patterns of biodiversity in cities are poorly understood. We argue that humans directly control plants but relatively few animals and microbes-the remaining biological community is determined by this plant "template" upon which natural ecological and evolutionary processes act. As a result, conserving or reconstructing natural habitats defined by vegetation within urban areas is no guarantee that other components of the biological community will follow suit. Understanding the human-controlled and natural processes that alter biodiversity is essential for conserving urban biodiversity. This urban biodiversity will comprise a growing fraction of the world's repository of biodiversity in the future.

Endophyte-grass symbiosis is generally considered to be a classic example of microbe-plant symbiosis in which the fitness of the microbial symbiont and its host plant is closely linked, and thus, presumed to align the interests of partners toward mutually beneficial cooperation. Accumulating evidence seems to suggest that defensive mutualism provides the best framework for understanding plantendophyte interactions in general. We conducted a metaanalysis of 99 published studies on 36 plant (inc. both grass and tree species), 62 herbivore and 17 predator or parasitoid taxons to test the importance of defensive mutualism in multitrophic interactions. In general, statistical perusal revealed that we still know little about these seemingly well-studied biological interactions. The conceptual framework for endophyte-grass interactions has largely been based on endophyte-plant-herbivore studies of two, economically important, artificially selected and introduced agricultural grass species, tall fescue and perennial ryegrass, and two generalist invertebrate pests. Only 10 original publications provided data of higher trophic levels. Consistent with the defensive mutualism hypothesis, the meta-analysis indicates that endophytes slightly increase grass resistance to herbivores, and the defensive mutualism appears to be most commonly detected in systemic and vertically transmitted grass endophytes compared to horizontally transmitted tree endophytes. However, variation appears to increase when higher trophic levels are considered. In addition to taxonomical bias, the literature is strongly biased toward short-term laboratory and greenhouse experiments rather than field conditions. Thus, current literature is insufficient to capture the breadth of variability inherent in the wild grassendophyte populations and communities, and the general importance of defensive mutualism remains to be solved in future studies.

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s-aryThe occurrence and topographical mapping of the gastric Helcobacter-like organisms (GHLOs) and their association with histological changes were studied in apparently healthy dogs and cats. Multiple samples were collected for histological examination from the fundus, corpus and antmm of the stomach of 10 dogs and 10 cats. Fundus and corpus were also sampled for transmission electron microscopy (three dogs, six cats), and for culture (eight dogs, six cats). In all dogs, GHLOs were detected in the fundus and corpus, and in the anmm of nine dogs, and significantly more often in the fundus and corpus (in all sample sites examined) than the antmm (P < 0.01). In cats, GHLOs were demonstrated in 6/10 individuals, and in all regions and sample sites. In dogs GHLOs were detected in all sample sites of the fundus and corpus. Lymphocytes, plasma cells and lymphocyte aggregates were found in all dogs in all regions; there were significantly more plasma cells in the antmm than in the corpus (P < 0.05). Neutrophils were found in six dogs, and eosinophils in seven dogs. In cats, lymphocyte aggregates were found only in GHLO-positive cats, which also had more lymphocytes in the fundus and corpus than GHLO-negative ones (P < 0.05). In dogs, no statistically significant association was found between the number of GHLOs and inflammatory parameters. Four dogs showed histological changes comparable to mild chronic gasmtis and another six dogs to mild active chronic gastritis. Mild chronic gastritis was found in the antmm of all cats, and it occurred significantly more often in the anmm than in other regions (P < 0.01). In cats, there was a statistically significant association between GHLOs and chronic gastritis in the fundus and corpus (P < 0.05). GHLOs resembhng human 'Hehobuctcr hdmannii' were identified in all the dogs and cats studied by electron microscopy, and Helicobacterfe~ir in one dog in addition. Culture was successful in three dogs and one cat; 'H. hedmunnii' was identified in two of the dogs, and H j f r j in the third dog and the cat. GHLOs were found to be common in apparently healthy dogs and cats. Based on the results of this study, one sample from the fundus and corpus is enough to demonstrate GHLOs. In cats, GHLOs may cause histological changes comparable to chronic gastritis, but in dogs this association remained unclear. It is also questionable if the histological criteria for human gastritis, used in the present study, are suitable for dogs and cats.

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