Group swimming behaviour and energetics in bluegill Lepomis macrochirus and rainbow trout Oncorhynchus mykiss

Group swimming size influences metabolic energy consumption and swimming behaviour in fishes. Hydrodynamic flows and vortices of other fish are thought to be beneficial in terms of the energetic costs of swimming. Similarly, abiotic obstructions have been shown to have similar benefits with respect to metabolic consumption in swimming fish such as rainbow trout Oncorhynchus mykiss. The current study works to examine metabolic rates and swimming behaviours as a function of group swimming with bluegill sunfish Lepomis macrochirus and O. mykiss. Fishes were subjected to individual and group swimming in a respiratory swim tunnel to determine oxygen consumption as a proxy for the metabolic rate of swimming fish. In addition, fish movements within the swim tunnel test chamber were tracked to examine group swimming behaviour. We hypothesized that fish would benefit metabolically from group swimming. In the case of O. mykiss, we also hypothesized that groups would benefit from the presence of an abiotic structure, as has been previously observed in fish swimming individually. Our results suggest that the influence of group size on swimming metabolism is species specific. While L. macrochirus show decreased metabolic rate when swimming in a group compared to individually, O. mykiss did not show such a metabolic benefit from group swimming.     

Phylogenetic relationships within Serpulidae (Sabellida, Annelida) inferred from molecular and morphological data

We assessed phylogenetic relationships within Serpulidae (including Spirorbinae) using parsimony and Bayesian analyses of 18S rDNA, the D1 and D9−D10 regions of 28S rDNA, and 38 morphological characters. In total, 857 parsimony informative characters were used for 31 terminals, 29 serpulids and sabellid and sabellariid outgroups. Following ILD assessment the two sequence partitions and morphology were analysed separately and in combination. The morphological parsimony analysis was congruent with the results of the 2003 preliminary analysis by Kupriyanova in suggesting that a monophyletic Serpulinae and Spirorbinae form a clade, while the remaining serpulids form a basal grade comprising what are normally regarded as Filograninae. Bremer support values were, however, quite low throughout. In contrast, the combined analyses of molecular and morphological data sets provided highly resolved and well-supported trees, though with some conflict when compared to the morphology-only analysis. Spirorbinae was recovered as a sister group to a monophyletic group comprising both 'filogranin' taxa ( Salmacina , Filograna , Protis , and Protula ) and 'serpulin' taxa such as Chitinopoma , Metavermilia , and Vermiliopsis . Thus the traditionally formulated subfamilies Serpulinae and Filograninae are not monophyletic. This indicates that a major revision of serpulid taxonomy is needed at the more inclusive taxonomic levels. We refrain from doing so based on the present analyses since we feel that further taxon sampling and molecular sequencing are required. The evolution of features such as the operculum and larval development are discussed.     

Five colour morphs and three new species of Gyptis (Hesionidae, Annelida) under a jetty in Edithburgh, South Australia

We report five different colour morphs of the hesionid polychaete genus Gyptis co-occurring in a small area in shallow water under Edithburgh jetty, South Australia. The five morphs cannot be separated using standard morphological features, but phylogenetic analyses of sequence data (COI and ITS1) unequivocally show that three species are present, introduced as Gyptis simpsonorum , new species, G. paucilineata , new species and G. polymorpha , new species. Gyptis simpsonorum has a speckled pigmentation pattern and G. paucilineata a few transverse lines on specific segments. Gyptis polymorpha is polymorphic with three different, distinct pigmentation patterns, either as dense transverse lines, as a thin longitudinal, mid-dorsal line, or as an uniformly dark dorsum. The speckled pigmentation likely represents the plesiomorphic condition, and G. propinqua is the closest known relative to these new species.     

Description of a fertilization-independent obligate apomictic species: Corunastylis apostasioides Fitzg

The Australian midge orchid Corunastylis apostasioides of the tribe Diurideae has completely eliminated any male contribution in the process of seed formation, which occurs directly from the maternal tissue by a process termed apomixis. Here, we report C. apostasioides to be an obligate apomictic species devoid of any sexuality and compare its development to a close sexual relative C. fimbriata (R. Br.) D.L. Jones & M.A. Clem. Apomictic characteristics in C. apostasioides include production of seed in absence of fertilization, frequently closed flowers, production of immature pollen in non-dehiscent anthers, expansion of ovaries despite the lack of fertilization and the absence of a citronella scent that is found in C. fimbriata produced to attract pollinating vinegar flies (Jones 2006). The nature of apomixis in C. apostasioides was examined by ovule histology and amplified fragment length polymorphism (AFLP) in each case drawing comparison with sexual C. fimbriata. In C. apostasioides the central megaspore mother cell undergoes diplosporic apomixis, while additional embryos are derived from nucellar or integument initials formed by sporophytic apomixis. Typical of apomicts, C. apostasioides is polyploid compared to the sexual C. fimbriata. The divergences of C. apostasioides from sexuality to apomictic development are discussed.     

人HCN4通道的滞后现象:影响窦房结起搏的潜在决定因素(英文)

超极化活化环核苷酸门控(hyperpolarization-activated cyclic-nucleotide-gated,HCN)通道参与调制心脏跳动的节律和速率。与HCN1和HCN2有所不同,慢通道HCN4可能不存在电压依赖的滞后现象。本研究采用单细胞膜片钳方法,在稳定转染hHCN4的HEK293细胞上进行电生理记录,观察hHCN4通道是否存在滞后现象,以及cAMP对其的调制作用;同时采用实时定量RT-PCR方法检测窦房结和心房组织中HCNs的表达。电压钳实验结果显示hHCN4电流(Ih)激活随着保持电位超极化的变化而向去极化方向移动。三角电位变化钳(triangular ramp)和动作电位钳的结果也显示了hHCN4的滞后现象。cAMP增加Ih电流幅度,且使电流激活向去极化方向移动,从而改变内源性hHCN4滞后行为。RT-PCR结果显示,人窦房结组织主要表达HCN4,占75%,HCN1占21%,HCN2占3%,HCN3占0.7%。以上结果提示,人窦房结组织主要表达HCN4亚型,hHCN4的Ih存在电压依赖性的滞后现象,且受cAMP调制。由此推断,hHCN4通道的滞后现象可能在窦房结起搏活动中起到了关键作用。     

Bias? What bias? The evolution of downstream larval‐feeding in animals

The homology of larval-feeding modes has been a major element in recent discussions about animal phylogeny. 'Downstream-feeding' is one of the two main larval-feeding modes, and is usually equated to an opposed-band system involving ciliary bands called the prototroch and metatroch. Larval-feeding in Spiralia is reviewed here and the homology hypothesis of downstream larval-feeding is expanded, encompassing any feeding involving the prototroch. It is often argued that the presence of planktotrophic larvae using downstream-feeding is plesiomorphic among spiralian animals, and that there is a bias in transformations, such that feeding larvae tend to be lost rather than gained. These hypotheses are assessed in relation to the Spiralia, Trochozoa and particularly polychaete annelids. Cladistic parsimony analyses are performed based on datasets of Rouse & Fauchald (1997) and Rouse (1999) , with an additional character based on downstream larval-feeding. Methods adopted to assess the possibility of a bias in transformations towards loss of downstream larval-feeding include: expanded primary homology arguments, character transformations favouring reversals and polymorphic terminals coded as having downstream larval-feeding. These measures all tend to favour the possibility that downstream larval-feeding will be plesiomorphic, and tends to be lost rather than gained. Nevertheless, all analyses show that downstream larval-feeding is not plesiomorphic, and appears to have evolved multiple times. The results support a conclusion that the prototroch has become associated with feeding a number of times. Hypotheses of metazoan phylogeny that are predicated on the assumption that downstream-feeding larvae are plesiomorphic (e.g. Peterson et al . 1997 ) should be re-assessed.     

Immune modulation by IL-10 gene transfer via viral vector and plasmid DNA: implication for gene therapy.

In the present report, we have evaluated and compared the modulatory effect of the cytokine interleukin (IL)-10 expressed via viral vector or plasmid DNA on viral antigen-induced cutaneous inflammatory lesions. Our data demonstrate the superior potency of both recombinant vaccinia virus and herpes simplex virus IL-10 expression vectors after single intramuscular administration, but the effects were only short term and only functioned in animals lacking immunity to the viral vectors used for modulation. In contrast, modulatory effects achieved by plasmid DNA expressing IL-10 were delayed in onset and milder in effect but were far more persistent than those achieved by viral vectors. Moreover, plasmid DNA expressing IL-10 provided effective modulation when given repeatedly to animals. Our data also showed that IL-10 gene delivery resulted in a systemic and durable modulatory effect while the effect caused by a single IL-10 protein treatment was transient and confined to the injected site. Our results imply that the viral vector system is superior for obtaining short-term effects, whereas the plasmid DNA approach represents a better strategy to achieve gene therapy to modulate chronic inflammatory lesions.     

Intraspecific interactions in a high‐density leopard population

Although less studied than interspecific interactions, interactions among members of the same species can influence space use and temporal activity. Using techniques commonly applied to the analysis of interspecific interactions—multispecies occupancy modeling and the analysis of temporal activity patterns—we studied intraspecific interactions within a high‐density population of Persian leopards (Panthera pardus saxicolor) in Tandoureh National Park, northeastern Iran. Using camera‐trap data, we investigated spatiotemporal interactions between male leopards, lone female leopards, and families (cubs/females with cubs). While we hypothesized that male and female leopards would display different temporal activity patterns, we did not predict spatial avoidance between these groups. We also predicted that leopard families would exhibit spatiotemporal avoidance from male leopards due to the risk of infanticide. Contrary to our expectations, we did not find any evidence for spatial or temporal avoidance between leopard families and adult male leopards. Male and lone female leopards exhibited positive pairwise co‐occurrence, consistent with reports of high overlap between male and female leopard home ranges. While a high level of overlap in temporal activity patterns was found between males/lone females and males/families, there was evidence for variation in the proportion of time each leopard group was active in particular periods of the diel cycle. Male leopards showed cathemeral activity, while lone females and families were more active during daylight hours. The application of these techniques to interactions within a species has improved understanding of the ecology and behavior of this endangered solitary carnivore.     

Changes in Mineral Content of Eucalyptus marginata and E. calophylla Grown under Controlled Conditions and Inoculated with Phytophthora cinnamomi

Mineral concentrations in infected roots and shoots were compared with similar material, but pathogen free, for the susceptible Eucalyptus marginata and the field resistant E. calophylla. All plants were mycorrhiza-free, grown under controlled conditions and inoculated with an axenic suspension of zoospores of Phytophthora cinnamomi. Plant material was ashed 30 days after inoculation and analyzed in an external proton beam using PIXE and nuclear reaction analyis to detect differences in mineral concentrations. The mineral content of infected roots of E. marginata was below that of the uninfected roots for all elements detected except chlorine, chromium and rubidium. The reductions were significant for calcium and copper. No such reduction was found, in E. calophylla roots, but some changes were detected. Shoot: root ratios of E. marginata showed significant differences associated with infection in phosphorus, calcium, copper and zinc. Relatively large differences were also recorded for sulphur chlorine and potassium. Shoot: root ratios of infected E. calophylla showed fewer differences but contained only half the concentrations of sulphur and potassium present in the controls. The reduced mineral concentrations reflect the failure in conduction of water and minerals through the infected and susceptible root system.