The impact of bird herbivory on macrophytes and the resilience of the clear-water state in shallow lakes: a model study

Land-use change associated with human development can alter aquatic habitat and imperil aquatic species. Fish are challenged when urban streams are altered, for example for stormwater conveyance, but little is known about how such activities influence the space use of individual fish. Electronic tagging and experimental displacement of fish can be used to explore site fidelity and homing behaviour of fish and can therefore be useful for testing hypotheses about space use and habitat selection. In this study, we used experimental displacement to determine how longnose dace (LND, Rhinichthys cataractae) utilize reaches within a watershed that have varying degrees of degradation. LND were tagged using passive integrated transponders (PIT tags), transported upstream, and released either into the natural stream reach, impaired stormwater drain reach, or at their confluence. Fixed PIT antennas were used to monitor movement of the PIT-tagged fish among the three reaches for a period of 3 weeks. LND exhibited dramatic and rapid selection against the stormwater drain. No LND moved into the drain and 97% of fish transported to the drain left within 24 h. LND were actively avoiding the stormwater drain, emphasizing the need for enhancement work to improve the biological connectivity of the system.     

Crusticorallina gen. nov., a nongeniculate genus in the subfamily Corallinoideae (Corallinales,Rhodophyta)

Molecular phylogenetic analyses of 18S rDNA (SSU) gene sequences confirm the placement of Crusticorallina gen. nov. in Corallinoideae, the first nongeniculate genus in an otherwise geniculate subfamily. Crusticorallina is distinguished from all other coralline genera by the following suite of morpho‐anatomical characters: (i) sunken, uniporate gametangial and bi/tetrasporangial conceptacles, (ii) cells linked by cell fusions, not secondary pit connections, (iii) an epithallus of 1 or 2 cell layers, (iv) a hypothallus that occupies 50% or more of the total thallus thickness, (v) elongate meristematic cells, and (vi) trichocytes absent. Four species are recognized based on rbcL, psbA and COI‐5P sequences, C. painei sp. nov., the generitype, C. adhaerens sp. nov., C. nootkana sp. nov. and C. muricata comb. nov., previously known as Pseudolithophyllum muricatum. Type material of Lithophyllum muricatum, basionym of C. muricata, in TRH comprises at least two taxa, and therefore we accept the previously designated lectotype specimen in UC that we sequenced to confirm its identity. Crusticorallina species are very difficult to distinguish using morpho‐anatomical and/or habitat characters, although at specific sites, some species may be distinguished by a combination of morpho‐anatomy, habitat and biogeography. The Northeast Pacific now boasts six coralline endemic genera, far more than any other region of the world.     

Ectoine accumulation in Brevibacterium epidermis

As a halotolerant bacterial species, Brevibacterium epidermis DSM 20659 can grow at relatively high salinity, tolerating up to 2 m NaCl. It synthesizes ectoine and the intracellular content increases with the medium salinity, with a maximum of 0.14 g ectoine/g CDW at 1 m NaCl. Sugar-stressed cells do not synthesize ectoine. Ectoine synthesis is also affected by the presence of external osmolytes. Added betaine is taken up and completely replaced ectoine, while l-proline is only temporarily accumulated after which ectoine is synthesized. The strain can metabolize ectoine; l-glutamate is a better carbon source for ectoine synthesis than l-aspartate.     

Up-regulation of TRPV1 in mononuclear cells of end-stage kidney disease patients increases susceptibility to N-arachidonoyl-dopamine (NADA)-induced cell death

Transient receptor potential vanilloid (TRPV) 1 channels function as sensors for a variety of noxious and inflammatory signals, including capsaicin, heat and protons, and are up-regulated under inflammatory conditions. As end-stage kidney disease (ESKD) is associated with chronic inflammation, impaired immunity and depressed lymphocyte numbers, we sought to determine whether altered TRPV1 (and related TRPV2) expression in immune cells might be a contributing factor. TRPV1 and TRPV2 mRNA expression in peripheral blood mononuclear cells (PBMC) was similar in controls and ESKD patients by quantitative real-time RT-PCR. However, using immunocytochemistry, TRPV1-immunoreactivity was significantly higher and TRPV2-immunoreactivity was significantly lower in PBMC from ESKD patients compared to controls. The plant-derived TRPV1 agonists, capsaicin and resiniferatoxin (RTX) and the putative endovanilloid/endocannabinoids, N-arachidonoyl-dopamine (NADA) and N-oleoyl-dopamine (OLDA), induced concentration-dependent death of PBMC from healthy donors with a rank order of potency of RTX > NADA > OLDA >> capsaicin. TRPV1 (5′-iodoresiniferatoxin) and cannabinoid (CB₂; AM630) receptor antagonists blocked the cytotoxic effect of NADA. In subsequent experiments, PBMC from ESKD patients exhibited significantly increased susceptibility to NADA-induced death compared to PBMC from controls. The apparent up-regulation of TRPV1 may be a response to the inflammatory milieu in which PBMC exist in ESKD and may be responsible for the increased susceptibility of these cells to NADA-induced death, providing a possible explanation as to why ESKD patients have reduced lymphocyte counts and impaired immune function. Thus, TRPV1 (and possibly CB₂) antagonists may have potential for the treatment of immune dysfunction in ESKD.     

Genomic and epigenomic instability, fragile sites, schizophrenia and autism

Increasing evidence links genomic and epigenomic instability, including multiple fragile sites regions to neuropsychiatric diseases including schizophrenia and autism. Cancer is the only other disease associated with multiple fragile site regions, and genome and epigenomic instability is a characteristic of cancer. Research on cancer is far more advanced than research on neuropsychiatric disease; hence, insight into neuropsychiatric disease may be derived from cancer research results. Towards this end, this article will review the evidence linking schizophrenia and other neuropsychiatric diseases (especially autism) to genomic and epigenomic instability, and fragile sites. The results of studies on genetic, epigenetic and environmental components of schizophrenia and autism point to the importance of the folate-methionine-transulfuration metabolic hub that is diseases also perturbed in cancer. The idea that the folate-methionine-transulfuration hub is important in neuropsychiatric is exciting because this hub present novel targets for drug development, suggests some drugs used in cancer may be useful in neuropsychiatric disease, and raises the possibility that nutrition interventions may influence the severity, presentation, or dynamics of disease.     

The Batten disease Palmitoyl Protein Thioesterase 1 gene regulates neural specification and axon connectivity during Drosophila embryonic development

Palmitoyl Protein Thioesterase 1 (PPT1) is an essential lysosomal protein in the mammalian nervous system whereby defects result in a fatal pediatric disease called Infantile Neuronal Ceroids Lipofuscinosis (INCL). Flies bearing mutations in the Drosophila ortholog Ppt1 exhibit phenotypes similar to the human disease: accumulation of autofluorescence deposits and shortened adult lifespan. Since INCL patients die as young children, early developmental neural defects due to the loss of PPT1 are postulated but have yet to be elucidated. Here we show that Drosophila Ppt1 is required during embryonic neural development. Ppt1 embryos display numerous neural defects ranging from abnormal cell fate specification in a number of identified precursor lineages in the CNS, missing and disorganized neurons, faulty motoneuronal axon trajectory, and discontinuous, misaligned, and incorrect midline crossings of the longitudinal axon bundles of the ventral nerve cord. Defects in the PNS include a decreased number of sensory neurons, disorganized chordotonal neural clusters, and abnormally shaped neurons with aberrant dendritic projections. These results indicate that Ppt1 is essential for proper neuronal cell fates and organization; and to establish the local environment for proper axon guidance and fasciculation. Ppt1 function is well conserved from humans to flies; thus the INCL pathologies may be due, in part, to the accumulation of various embryonic neural defects similar to that of Drosophila. These findings may be relevant for understanding the developmental origin of neural deficiencies in INCL.     

Analysis of Clostridium botulinum serotype E strains by using multilocus sequence typing, amplified fragment length polymorphism, variable-number tandem-repeat analysis, and botulinum neurotoxin gene sequencing

A total of 41 Clostridium botulinum serotype E strains from different geographic regions, including Canada, Denmark, Finland, France, Greenland, Japan, and the United States, were compared by multilocus sequence typing (MLST), amplified fragment length polymorphism (AFLP) analysis, variable-number tandem-repeat (VNTR) analysis, and botulinum neurotoxin (bont) E gene sequencing. The strains, representing environmental, food-borne, and infant botulism samples collected from 1932 to 2007, were analyzed to compare serotype E strains from different geographic regions and types of botulism and to determine whether each of the strains contained the transposon-associated recombinase rarA, involved with bont/E insertion. MLST examination using 15 genes clustered the strains into several clades, with most members within a cluster sharing the same BoNT/E subtype (BoNT/E1, E2, E3, or E6). Sequencing of the bont/E gene identified two new variants (E7, E8) that showed regions of recombination with other E subtypes. The AFLP dendrogram clustered the 41 strains similarly to the MLST dendrogram. Strains that could not be differentiated by AFLP, MLST, or bont gene sequencing were further examined using three VNTR regions. Both intact and split rarA genes were amplified by PCR in each of the strains, and their identities were confirmed in 11 strains by amplicon sequencing. The findings suggest that (i) the C. botulinum serotype E strains result from the targeted insertion of the bont/E gene into genetically conserved bacteria and (ii) recombination events (not random mutations) within bont/E result in toxin variants or subtypes within strains.     

Factors affecting nest choice by Pekin ducks

To encourage nest use in breeder poultry flocks, it is important that nest boxes are attractive. Few studies have evaluated factors affecting nest attractiveness to ducks. We assessed the effects of nest box experience (Experiments 1 and 2) and features of nests, including degree of enclosure (Experiments 1 and 2) and the presence of an egg (Experiment 3), on nest site selection by sexually mature Pekin ducks. The hens were tested individually in pens containing different nest box choices. Nest preferences were determined based on the locations of 14 successively laid eggs. Ducks in Experiment 1 were provided with nest box access prior to the onset of lay (20 weeks of age, EXP group, N = 12) or at the time of preference testing (35 weeks of age, DELAYED-EXP group, N = 12). Delaying nest box access by 15 weeks did not significantly affect the proportion of eggs laid in nest boxes rather than on the floor (P = 0.40). Regardless of experience ducks laid more than 66% of their eggs in nest boxes offering a higher degree of enclosure. Ducks in Experiment 2 were reared with either open-top (OP, N = 12) or closed-top (CL, N = 12) boxes. Regardless of rearing condition, ducks preferred boxes with the highest level of enclosure offered. Ducks laid twice the expected proportion (25%) of eggs in CL boxes with curtains (P = 0.0004). CL boxes without curtains were used as predicted by chance, 25% (P = 0.746), while OP boxes with (P = 0.009) and without (P = 0.015) curtains each contained only half the expected number of eggs. Ducks in Experiment 3 were provided with two nest boxes, one of which contained the egg laid the previous day. Each day, the newly laid egg was marked and either placed back in the nest box where it was found (HANDLED, N = 12) or moved into the adjacent nest box (MOVED, N = 12). Ducks in HANDLED and MOVED laid 97.6% and 79.8%, respectively, of their eggs in boxes containing the previous day's egg. While ducks in HANDLED were consistent in their choice throughout the test, those in MOVED developed the preference over time (P = 0.039), suggesting that the preference for laying in a nest containing an egg may be influenced by experience. These results indicate that nest box enclosure and the presence of an egg are important in determining the nesting choices of Pekin ducks. Incorporating these features into nest boxes may be useful for increasing consistency of nest use in breeder duck flocks.     

Metallic copper corrosion rates, moisture content, and growth medium influence survival of copper ion-resistant bacteria

The rapid killing of various bacteria in contact with metallic copper is thought to be influenced by the influx of copper ions into the cells, but the exact mechanism is not fully understood. This study showed that the kinetics of contact killing of copper surfaces depended greatly on the amount of moisture present, copper content of alloys, type of medium used, and type of bacteria. We examined antibiotic- and copper ion-resistant strains of Escherichia coli and Enterococcus faecium isolated from pig farms following the use of copper sulfate as feed supplement. The results showed rapid killing of both copper ion-resistant E. coli and E. faecium strains when samples in rich medium were spread in a thin, moist layer on copper alloys with 85% or greater copper content. E. coli strains were rapidly killed under dry conditions, while E. faecium strains were less affected. Electroplated copper surface corrosion rates were determined from electrochemical polarization tests using the Stern–Geary method and revealed decreased corrosion rates with benzotriazole and thermal oxide coating. Copper ion-resistant E. coli and E. faecium cells suspended in 0.8% NaCl showed prolonged survival rates on electroplated copper surfaces with benzotriazole coating and thermal oxide coating compared to surfaces without anti-corrosion treatment. Control of surface corrosion affected the level of copper ion influx into bacterial cells, which contributed directly to bacterial killing.