Effect of single-species and mixed-species leaf leachate on bacterial communities in biofilms

Bacterial communities in two shallow eutrophic aquatic ecosystems (eastern China) were studied using culture-dependent methods, and their correlations with the other water parameters were analyzed. Although the values of the comprehensive trophic state index in Xizi Lake and Hangzhou Canal were almost identical, the abundances of cultivable bacterial communities, such as protein-hydrolyzing bacteria (PHB), fecal coliforms (FC), nitrogen-utilizing bacteria, phosphate-mineralizing bacteria, and cellulose-decomposing bacteria (CDB), differed significantly. They were much less in Xizi Lake than in Hangzhou Canal. Correlation analyses indicated that the abundances of physiological groups of bacteria were determined mainly by the biomasses of phytoplankton and zooplankton, rather than by the utilized substrates. Xizi Lake was an algae-dominated aquatic ecosystem, a situation that mainly arose from the influx of inorganic nutrients, and the Hangzhou Canal was bacteria-dominated due to the influx of organic sewage. Molecular characterization and phylogenetic analysis of isolates showed that there were 6 phylogenetic lineages out of 15 isolates screened from Xizi Lake, including γ-proteobacteria (5), β-proteobacteria (3), α-proteobacteria (2), actinobacteria (1), firmicutes (4), and bacteroidetes (1). While in Hangzhou Canal there were only 4 bacterial groups among 22 isolates, γ-proteobacteria comprised about 82%, α-proteobacteria made up 9%, firmicutes and bacteroidetes made up only 4.5%, respectively, and no β-proteobacteria were found. Enterobacteriaceae were the principal bacteria components in the two aquatic ecosystems, especially in the sewage-polluted Hangzhou Canal. It can be concluded preliminarily that the bacterial diversity in Xizi Lake is richer than that in Hangzhou Canal. Handling editor: J. Padisak     

Chemical composition of lipopolysaccharides from Legionella bozemanii and Legionella longbeachae

Lipopolysaccharides (LPS) from Legionella bozemanii serogroup 1 and Legionella longbeachae serogroup 1 were subjected to chemical analyses. The lipid A part of both LPSs contained 2,3-dideoxy-2,3-diamino-d-glucose as major constituents and d-glucosamine and glycerol as minor constituents of the sugar backbone structure. Both LPSs exhibited a very complex fatty acid composition. Twenty amide-linked 3-hydroxy fatty acids were detected in LPS of L. longbeachae, whereas seventeen were encountered in LPS of L. bozemanii. Both LPSs contained nine ester-linked nonhydroxy fatty acids and the unique long-chain fatty acids 27-oxo-octacosanoic acid, 29-oxotriacontanoic acid, heptacosane-1,27-dioic acid and nonacosane-1,29-dioic acid. SDS-PAGE showed that L. bozemanii produced smooth-form LPS, whereas L. longbeachae LPS was mainly of the R-type. Composition analyses were in accordance with these electrophoretic patterns. d-Quinovosamine and l-fucosamine constituted 80 mol% of the polysaccharide part of L. bozemanii LPS. Other sugars identified were d-glucosamine, d-mannose, d-glucose, l-rhamnose, d-glycero-d-manno-heptose, l-glycero-d-mannoheptose, 2-keto-3-deoxy-octonic acid and glycerol. The polysaccharide chain from LPS of L. longbeachae appeared to be shorter, but composed of the same sugars except l-fucosamine. Both LPSs contained glycerol phosphate and glucosamine phosphate and L. longbeachae LPS contained in addition glucose phosphate.Abbreviations EI Electron impact - GlcN3N 2,3-Diamino-2,3-dideoxy-d-glucose - HPAEC High pH anion-exchange chromatography - Kdo 2-Keto-3-deoxy-octonic acid - LPS Lipopolysaccharide - PCP Phenol/chloroform/petroleum ether solvent - PED Pulsed electrochemical detection - PS Polysaccharide - TFA Trifluoroacetyl - TMS Trimethylsilyl     

Non-photochemical quenching of Fo in leaves is emission wavelength dependent: consequences for quenching analysis and its interpretation

The effects of light-induced non-photochemical quenching on the minimal F_o, and variable F_v, fluorescence emissions at 690 and 730 nm in leaves were determined. Non-photochemical quenching of F_o, but not F_v, was found to be dependent upon the wavelength of emission, and was greater at 690 nm than at 730 nm. For emission at 730, compared to at 690 nm, approx. 30% of F_o was not affected by non-photochemical quenching processes in leaves of C3 plants; in maize leaves this was found to be approx. 50%. The data indicate that a substantial proportion of the pigments contributing to F_o emission at 730 nm are not quenched by light-induced, non-photochemical quenching processes and that there are large differences in the pigment matrices contributing to F_o and F_v emissions at 730 nm, compared to those at 690 nm. These findings have important implications for the accurate estimation and interpretation of non-photochemical quenching of fluorescence parameters and their use in the calculation of photochemical efficiencies in leaves. Measurements of fluorescence emissions at wavelengths above 700 nm are likely to give rise to significant errors when used for determinations of photochemical and non-photochemical quenching parameters.     

Growth and foraging consequences of facultative paedomorphosis in the tiger salamander,Ambystoma tigrinum nebulosum

Summary Facultative paedomorphosis in salamanders occurs when larvae respond to varying environmental conditions by either metamorphosing into terrestrial metamorphic adults or retaining their larval morphology to become sexually mature paedomorphic adults. Several hypotheses have been proposed for the evolutionary maintenance of this environmentally induced dimorphism, but few data are available to assess them adequately. We studied a montane population of the tiger salamander,Ambystoma tigrinum nebulosum, and measured the adult growth rate and body condition across three growing seasons to assess the relative costs and benefits of each morph. Metamorphic adults grew more than paedomorphic adults in terms of snout—vent length across years and in weight within years. Dietary analyses and foraging experiments revealed some of the proximate factors that may underlie these differential growth patterns. Across all prey, metamorphs had significantly higher biomass and calories per stomach sample than paedomorphs. Metamorphic diets primarily consisted of the fairy shrimpBranchinecta coloradensis, whereas paedomorphic diets contained a variety of benthic and terrestrial invertebrates. Foraging experiments revealed that both morphs are more successful at capturing fairy shrimp relative to other prey types and both show high electivity toward this prey. However, fairy shrimp occurred only in non-permanent ponds and thus are inaccessible to paedomorphs, which can survive only in permanent ponds. Paedomorphs also experience higher levels of intraspecific competition with large larvae in permanent ponds than metamorphs do in non-permanent ponds. Thus, metamorphs obtain a growth advantage over paedomorphs by foraging in non-permanent ponds that contain fairy shrimp and have reduced intraspecific competition. These results suggest that paedomorphs should have decreased fitness relative to metamorphs, primarily because metamorphs can move into the best habitats for growth. The net fitness effect of morph-specific differences in dispersal depend on whether there are trade-offs with other life history traits. Nonetheless, because the relative benefit of metamorph dispersal will change with environmental conditions in permanent ponds and the surrounding habitat, the relative fitness payoff to each morph should track changes in the environment. Thus, facultative paedomorphosis may be maintained in part by variable, environmentally-specific fitness payoffs to each morph.     

Fruit Mineral Contents of Six Wild Species of the North Andean Patagonia, Argentina

The fruit mineral contents (K, Ca, Ba, Br, Zn, Co, Cr, Fe, Na, Rb, Cs, and Sr) of four native and two exotic naturalized shrubs growing in different areas of the Andean Patagonian region of Argentina were investigated. Native species Berberis darwinii, Berberis microphylla (Berberidaceae), Aristotelia chilensis (Elaeocarpaceae) and Ribes magellanicum (Saxifragaceae) produce small berries while the fruits of the exotic species Rosa rubiginosa and Rosa canina (Rosaceae) are aggregates of aquenes. They are used to prepare jams, tea, liquors, and ice creams. Native shrub fruits had higher content of Br, Zn, Co, Cr, Fe, Mo, and Na than those of the exotic naturalized species. Rosa species showed the highest contents of Ca and Ba in their fruits (the mean content doubled those of the native plant fruits). The fruit nutrient content found in the studied species was similar or higher than other values reported for fruits of temperate and tropical species in the world.     

Phylogenetic signals in thermal traits remain stronger in the tropics if we can believe published physiological data. A reply to McKechnie et al., “Data quality problems undermine analyses of endotherm upper critical temperatures”

Due to concerns about data quality, McKechnie, Coe, Gerson, and Wolf ( 2016 ) questioned the conclusions of our study (Khaliq et al., 2015 ) published in this journal. Here, we argue that most of the questioned data points are in fact useful for macrophysiological analyses, mostly because the vast majority of data are explicitly reported in the peer‐reviewed physiological literature. Furthermore, we show that our conclusions remain largely robust irrespective of the data inclusion criterion. While we think that constructive debates about the adequate use of primary data in meta‐studies as well as more transparency in data inclusion criteria are indeed useful, we also emphasize that data suitability should be evaluated in the light of the scope and scale of the study in which they are used. We hope that this discussion will not discourage the exchange between disciplines such as biogeography and physiology, as this integration is needed to address some of the most urgent scientific challenges.     

From the Apennines to the Alps: colonization genetics of the naturally expanding Italian wolf (Canis lupus) population

Wolves in Italy strongly declined in the past and were confined south of the Alps since the turn of the last century, reduced in the 1970s to approximately 100 individuals surviving in two fragmented subpopulations in the central-southern Apennines. The Italian wolves are presently expanding in the Apennines, and started to recolonize the western Alps in Italy, France and Switzerland about 16 years ago. In this study, we used a population genetic approach to elucidate some aspects of the wolf recolonization process. DNA extracted from 3068 tissue and scat samples collected in the Apennines (the source populations) and in the Alps (the colony), were genotyped at 12 microsatellite loci aiming to assess (i) the strength of the bottleneck and founder effects during the onset of colonization; (ii) the rates of gene flow between source and colony; and (iii) the minimum number of colonizers that are needed to explain the genetic variability observed in the colony. We identified a total of 435 distinct wolf genotypes, which showed that wolves in the Alps: (i) have significantly lower genetic diversity (heterozygosity, allelic richness, number of private alleles) than wolves in the Apennines; (ii) are genetically distinct using pairwise F(ST) values, population assignment test and Bayesian clustering; (iii) are not in genetic equilibrium (significant bottleneck test). Spatial autocorrelations are significant among samples separated up to c. 230 km, roughly correspondent to the apparent gap in permanent wolf presence between the Alps and north Apennines. The estimated number of first-generation migrants indicates that migration has been unidirectional and male-biased, from the Apennines to the Alps, and that wolves in southern Italy did not contribute to the Alpine population. These results suggest that: (i) the Alps were colonized by a few long-range migrating wolves originating in the north Apennine subpopulation; (ii) during the colonization process there has been a moderate bottleneck; and (iii) gene flow between sources and colonies was moderate (corresponding to 1.25-2.50 wolves per generation), despite high potential for dispersal. Bottleneck simulations showed that a total of c. 8-16 effective founders are needed to explain the genetic diversity observed in the Alps. Levels of genetic diversity in the expanding Alpine wolf population, and the permanence of genetic structuring, will depend on the future rates of gene flow among distinct wolf subpopulation fragments.     

The first complete mitochondrial genome sequence of Nanorana parkeri and Nanorana ventripunctata (Amphibia: Anura: Dicroglossidae), with related phylogenetic analyses

Members of the Nanorana genus (family Dicroglossidae) are often referred to as excellent model species with which to study amphibian adaptations to extreme environments and also as excellent keystone taxa for providing insights into the evolution of the Dicroglossidae. However, a complete mitochondrial genome is currently only available for Nanorana pleskei. Thus, we analyzed the complete mitochondrial genomes of Nanorana parkeri and Nanorana ventripunctata to investigate their evolutionary relationships within Nanorana and their phylogenetic position in the family Dicroglossidae. Our results showed that the genomes of N. parkeri (17,837 bp) and N. ventripunctata (18,373 bp) encode 13 protein‐coding genes (PCGs), two ribosomal RNA genes, 23 transfer RNA (tRNA) genes, and a noncoding control region. Overall sequences and genome structure of the two species showed high degree of similarity with N. pleskei, although the motif structures and repeat sequences of the putative control region showed clear differences among these three Nanorana species. In addition, a tandem repeat of the tRNA‐Met gene was found located between the tRNA‐Gln and ND2 genes. On both the 5′ and 3′‐sides, the control region possessed distinct repeat regions; however, the CSB‐2 motif was not found in N. pleskei. Based on the nucleotide sequences of 13 PCGs, our phylogenetic analyses, using Bayesian inference and maximum‐likelihood methods, illustrate the taxonomic status of Nanorana with robust support showing that N. ventripunctata and N. pleskei are more closely related than they are to N. parkeri. In conclusion, our analyses provide a more robust and reliable perspective on the evolutionary history of Dicroglossidae than earlier analyses, which used only a single species (N. pleskei).     

A new genus of Aeolothripidae (Thysanoptera) from New Zealand and New Caledonia

Desmidothrips n.gen. is described from New Zealand, with walkerae n.sp. as type‐species. Aeolothrips inauditus Bianchi from New Caledonia is transferred to this new genus. Desmidothrips is related to the Australian genus Desmothrips, and is the only member of the Aeolothripidae native to New Zealand.