Discontinuous genetic variation among mesophilic Naegleria isolates: further evidence that N. gruberi is not a single species.

Naegleria isolates which are currently placed in the type species N. gruberi display great genetic, physiological and morphological heterogeneity. There are two possible interpretations of the nature of this species--that N. gruberi is a species complex or that it is a single continuously variable species. To distinguish between these alternatives, allelic states were determined for 33 loci in 74 new isolates selected to represent wide geographic sources and diverse temperature limits for growth. The results were compared with data for culture collection strains of N. gruberi and other species in the genus. The isolates formed a discontinuous series of clusters, separated by genetic distances similar to those separating the better-characterised taxa N. fowleri, N. lovaniensis, N. jadini, N. australiensis australiensis and N. australiensis italica. Culture collection strains assigned to N. gruberi fell into six distinct clusters, while other clusters were not represented by reference strains. The data are most consistent with the interpretation that N. gruberi is a group of several distinct species, each equivalent to the recently described species in the genus. Naegleria andersoni andersoni and N. andersoni jamiesoni also formed two distinct clusters, equivalent to species. Characteristics temperature limits for growth show that the mesophilic species are ecological as well as genetic entities.     

Grooming and Anxiety in Barbary Macaques

Grooming is a fundamental component of sociality in many gregarious animal species, and elucidating the costs and benefits of this behaviour is crucial for understanding its function. There is evidence that animals giving grooming pay a cost in terms of the time and energy they invest, while recipients benefit not just from the removal of dirt and parasites, but also from the relaxing effects of being groomed. Recently, however, studies of primates have indicated that giving grooming may also provide such hedonic benefits, reducing levels of stress or anxiety in the groomer. In this study of free‐ranging adult female Barbary macaques at Trentham Monkey Forest (Stoke‐on‐Trent, UK), we tested the hypothesis that grooming reduces anxiety in the donor and/or the recipient. During focal follows, we quantified females' rates of self‐scratching as a behavioural index of their anxiety levels. Self‐scratching rates in the 2‐min periods after bouts of grooming (given, received and reciprocated) were compared to overall mean self‐scratching rates; we predicted that if grooming reduces anxiety, self‐scratching rates would be significantly lower after grooming bouts than mean levels. We first analysed all grooming bouts and then analysed separately grooming bouts with adult males, with all adult females, with subordinate adult females and with dominant adult females. Contrary to our prediction, self‐scratching rates were never seen to be lower after grooming than mean levels. In fact, for the majority of grooming partner–direction combinations, we found significantly higher rates of self‐scratching after grooming compared to mean levels. The hypothesis that grooming reduces anxiety was therefore not supported. Grooming seems in some cases to increase, not alleviate, anxiety. We explore possible explanations for these unexpected results.     

Stromal-cell-derived factor (SDF) 1-alpha in combination with BMP-2 and TGF-β1 induces site-directed cell homing and osteogenic and chondrogenic differentiation for tissue engineering without the requirement for cell seeding

The clinical translation of tissue engineering approaches is limited by the requirement of a cell source. Cell guidance is a new concept that provides an alternative approach, obviating a requirement for an external cell source. This relies on site-specific homing and differentiation of the patient??s own cells to an implanted scaffold through controlled delivery of cytokines. In this study, we used stromal-cell-derived factor 1-alpha (SDF-1??) in combination with bone morphogenic protein (BMP)-2 or transforming growth factor (TGF)-??1 to induce cell migration and osteogenic or chondrogenic differentiation, respectively, in implanted scaffolds in a rat model. A customized cytokine microdelivery apparatus was used to ensure the constant rate and concentration of cytokine delivery around the scaffold. The formation of osteoid or early cartilage was observed after 4?weeks in specimens treated with SDF-1?? and either BMP-2 or TGF-??1. The density of cellular infiltrate and formation of differentiated tissue were lower in scaffolds treated only with BMP-2 or TGF-??1. Thus, controlled SDF-1?? delivery induces cell migration into scaffolds and can result in enhanced osteogenesis and chondrogenesis when used in combination with differentiation cytokines for purposes of tissue engineering.     

A comparison between aquatic birds of lakes and coastal rivers in Florida

Aquatic birds were counted on five Gulf coast Florida rivers to determine if these river systems supported densities, biomass and species richness similar to those found on Florida lakes. Forty-two species were identified and for the species that were found on both Florida streams and lakes similar densities and biomass were encountered. As with Florida lakes, stream bird abundance and species richness were higher in winter months than in summer months, a consequence of migratory bird populations. Total bird abundance, biomass per unit of phosphorus, and species richness per unit of area were similar to data collected on Florida lakes. Thus, Florida rivers are capable of supplying sufficient resources to maintain bird densities, biomass and species richness values similar to lakes of equal size and nutrient concentrations and are therefore important habitats for aquatic bird populations. An examination of individual habitat characteristics indicates that water depth was inversely correlated and submersed aquatic vegetation was positively correlated with bird density, biomass and species richness within the river systems. While both habitat characteristics are important they are also inversely related making it difficult to separate the individual significance of each characteristic.     

AKAP9 Is Essential for Spermatogenesis and Sertoli Cell Maturation in Mice

Mammalian male fertility relies on complex inter- and intracellular signaling during spermatogenesis. Here we describe three alleles of the widely expressed A-kinase anchoring protein 9 (Akap9) gene, all of which cause gametogenic failure and infertility in the absence of marked somatic phenotypes. Akap9 disruption does not affect spindle nucleation or progression of prophase I of meiosis but does inhibit maturation of Sertoli cells, which continue to express the immaturity markers anti-Mullerian hormone and thyroid hormone receptor alpha in adults and fail to express the maturation marker p27^Kip1. Furthermore, gap and tight junctions essential for blood–testis barrier (BTB) organization are disrupted. Connexin43 (Cx43) and zona occludens-1 are improperly localized in Akap9 mutant testes, and Cx43 fails to compartmentalize germ cells near the BTB. These results identify and support a novel reproductive tissue-specific role for Akap9 in the coordinated regulation of Sertoli cells in the testis.     

Stable isotopes as indicators of wastewater effects on the macroinvertebrates of urban rivers

Rivers in urban locations frequently receive contaminated wastewater and particulate waste either directly from storm overflows or from sewage treatment facilities. Although many urban streams are now recovering from wide-scale historic pollution, lower-level effects on water chemistry, nutrients and biotic composition are still widespread. We aimed to determine whether such effects could be detected using stable isotope ratios (??¹⁵N, ??¹³C and ??³⁴S) in macroinvertebrates alone or in conjunction with traditional biomonitoring. Macroinvertebrates were collected upstream and downstream of 11 different secondary wastewater treatment works (WwTW) in South Wales and the Welsh borders (United Kingdom). Overall, mean invertebrate ??¹⁵N signatures downstream of the WwTW were significantly enriched despite variation amongst sites. Moreover, changes between upstream and downstream macroinvertebrate ??¹⁵N values were highly correlated with patterns in macroinvertebrate community composition, increased total macroinvertebrate abundance, and reduced Shannon Diversity and other biomonitoring indices (% EPT, % shredders and ASPT scores). Changes in invertebrate ??¹⁵N values also paralleled the consented discharge volumes and population equivalents from each WwTW. In contrast, isotopic ratios of ??¹³C and ??³⁴S were unable to distinguish or quantify wastewater input into the rivers but differences were apparent amongst study streams. Overall, these results suggest that macroinvertebrate ??¹⁵N signatures can detect and quantify the effects of secondary sewage treatment inputs to riverine ecosystems. Moreover, the method potentially provides a sensitive means for tracing sewage-derived nutrients into food webs while inferring effects on aquatic communities where sewage-loads are subtle or confounded by other stressors.