Conspecific and heterospecific plant–soil biota interactions of Lonicera japonica in its native and introduced range: implications for invasion success

Plant Ecology - We tested the ‘enemy release hypothesis’ in relation to Lonicera japonica to determine the effects of soil microbes on plant growth. It was hypothesized that plant...     

The impact of the Congo River and its tributaries on the rodent genus Praomys: speciation origin or range expansion limit?

We studied the taxonomy, distribution, and ecology of species within Praomys, a common rodent genus present in rainforests and montane forests in sub‐Saharan Africa. The taxonomy of the group is problematic, and for the sampled region of Kisangani (Democratic Republic of Congo) no prior genetic study has been published. We used a combination of molecular (cyt b sequencing) and craniometric techniques (canonical analyses of skull measurements) for the species identification of a total of 654 specimens. We confirm the presence of Praomys minor in the region, up to now only known from the type and paratype specimens. At least seven species are present in the Kisangani region, and two clades occur along both banks of the Congo River. The present‐day distribution of the genus seems to be influenced by large‐scale rainforest fragmentation related to drier periods in geological history. The Congo River could in this case constitute a modern barrier to gene flow when the climate enabled rainforest expansion. The tributaries of the Congo River play no role in limiting Praomys species distribution, apart from the Aruwimi River for Praomys jacksoni s.l. © 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 163 , 983–1002.     

Searching for the “sweet spot”: the foot rotation and parallel engagement of ankle ligaments in maximizing injury tolerance

Ligament sprains, defined as tearing of bands of fibrous tissues within ligaments, account for a majority of injuries to the foot and ankle complex in field-based sports. External rotation of the foot is considered the primary injury mechanism of syndesmotic ankle sprains with concomitant flexion and inversion/eversion associated with particular patterns of ligament trauma. However, the influence of the magnitude and direction of loading vectors to the ankle on the in situ stress state of the ligaments has not been quantified in the literature. The objective of the present study was to search for the maximum injury tolerance of a human foot with an acceptable subfailure distribution of individual ligaments. We used a previously developed and comprehensively validated foot and ankle model to reproduce a range of combined foot rotation experienced during high-risk sports activities. Biomechanical computational investigation was performed on initial foot rotation from \(20{^{\circ }}\) of plantar flexion to \(15{^{\circ }}\) of dorsiflexion, and from \(15{^{\circ }}\) of inversion to \(15{^{\circ }}\) of eversion prior to external rotation. Change in initial foot rotation shifted injury initiation among different ligaments and resulted in a wide range of injury tolerances at the structural level (e.g., 36–125 Nm of rotational moment). The observed trend was in agreement with a parallel experimental study that initial plantar flexion decreased the incidence of syndesmotic injury compared to a neutral foot. A mechanism of distributing even loads across ligaments subjected to combined foot rotations was identified. This mechanism is potential to obtain the maximum load-bearing capability of a foot and ankle while minimizing the injury severity of ligaments. Such improved understanding of ligament injuries in athletes is necessary to facilitate injury management by clinicians and countermeasure development by biomechanists.     

‘The importance of symbiosis in philosophy of biology: an analysis of the current debate on biological individuality and its historical roots’

Symbiosis plays a fundamental role in contemporary biology, as well as in recent thinking in philosophy of biology. The discovery of the importance and universality of symbiotic associations has brought new light to old debates in the field, including issues about the concept of biological individuality. An important aspect of these debates has been the formulation of the hologenome concept of evolution, the notion that holobionts are units of natural selection in evolution. This review examines the philosophical assumptions that underlie recent proposal of the hologenome concept of evolution, and traces those debates back in time to their historical origins, to the moment when the connection between the topics of symbiosis and biological individuality first caught the attention of biologists. The review is divided in two parts. The first part explores the historical origins of the connection between the notion of symbiosis and the concept of biological individuality, and emphasizes the role of A. de Bary, R. Pound, A. Schneider and C. Merezhkowsky in framing the debate. The second part examines the hologenome concept of evolution and explores four parallelisms between contemporary debates and the debates presented in the first part of the essay, arguing that the different debates raised by the hologenome concept were already present in the literature. I suggest that the novelty of the hologenome concept of evolution lies in the wider appreciation of the importance of symbiosis for maintaining life on Earth as we know it. Finally, I conclude by suggesting the importance of exploring the connections among contemporary biology, philosophy of biology and history of biology in order to gain a better understanding of contemporary biology.     

Evolution of the term “cellular senescence” and its impact on the current cytogerontological research

The term “cellular/cell senescence” was first introduced by Leonard Hayflick to describe the “age-related” changes in normal eukaryotic cells during aging in vitro, i.e., over the exhaustion of their mitotic potential. In the “classic” variant, it was assumed that cells “grow old” with the help of some internal mechanism, which leads to accumulation of various macromolecular defects (DNA damage in the first place). Currently, as a rule, “cellular senescence” means accumulation/appearance of particular “biomarkers of aging” in cells (they are most often transformed cells that do not demonstrate any replicative senescence) under the influence of various external factors (oxidative stress, H₂O₂, mitomycin C, ethanol, ionizing radiation, doxorubicin, etc.) that cause DNA damage. This phenomenon has been called DDR (DNA Damage Response). Among the said biomarkers, there are senescence-associated beta-galactosidase activity, expression of p53 and p21 proteins as well as of proteins involved in the regulation of inflammation, such as IL-6 or IL-8, activation of oncogenes, etc. Thus, “aging/senescence” of cells does not occur simply by itself—it takes place because of the influence of DNA-damaging agents. This approach, in my opinion, despite being very important to define a strategy to fight cancer, distracts us, yet again, from the study of the real mechanisms of aging. It should be emphasized that the “stationary phase aging” model developed in my laboratory also allows registering the occurrence of certain biomarkers of aging in cultured cells, but in this case they arise due to the restriction of their proliferation by contact inhibition, i.e., due to a rather physiological impact, which does not cause any damage to cells by itself (the situation is similar to what we observe in a whole multicellular organism).     

New damsel-dragonflies with “calopterygid”-like wing shape from the Middle Jurassic of China (Odonata: Isophlebioidea: Campterophlebiidae)

The new damsel-dragonflies Zygokaratawia incompleta nov. sp. and Parazygokaratawia azari nov. gen., nov. sp., closely related to the campterophlebiid genus Zygokaratawia, are described from the Middle Jurassic locality of the Daohugou and Chentaizi villages, respectively (Ningcheng County, Inner Mongolia, NE China). Parazygokaratawia nov. gen. and Zygokaratawia share a narrowly reduced cubito-anal area, unique synapomorphy in the Isophlebioptera. Campterophlebiids with this character are only known from the Daohugou biota.     

Galápagos and Californian sea lions are separate species: Genetic analysis of the genus Zalophus and its implications for conservation management

The climatic cycles with subsequent glacial and intergalcial periods have had a great impact on the distribution and evolution of species. Using genetic analytical tools considerably increased our understanding of these processes. In this review I therefore give an overview of the molecular biogeography of Europe. For means of simplification, I distinguish between three major biogeographical entities: (i) "Mediterranean" with Mediterranean differentiation and dispersal centres, (ii) "Continental" with extra-Mediterranean centres and (iii) "Alpine" and/or "Arctic" with recent alpine and/or arctic distribution patterns. These different molecular biogeographical patterns are presented using actual examples. Many "Mediterranean" species are differentiated into three major European genetic lineages, which are due to glacial isolation in the three major Mediterranean peninsulas. Postglacial expansion in this group of species is mostly influenced by the barriers of the Pyrenees and the Alps with four resulting main patterns of postglacial range expansions. However, some cases are known with less than one genetic lineage per Mediterranean peninsula on the one hand, and others with a considerable genetic substructure within each of the Mediterranean peninsulas, Asia Minor and the Maghreb. These structures within the Mediterranean sub-centres are often rather strong and in several cases even predate the Pleistocene. For the "Continental" species, it could be shown that the formerly supposed postglacial spread from eastern Palearctic expansion centres is mostly not applicable. Quite the contrary, most of these species apparently had extra-Mediterranean centres of survival in Europe with special importance of the perialpine regions, the Carpathian Basin and parts of the Balkan Peninsula. In the group of "Alpine" and/or "Arctic" species, several molecular biogeographical patterns have been found, which support and improve the postulates based on distribution patterns and pollen records. Thus, genetic studies support the strong linkage between southwestern Alps and Pyrenees, northeastern Alps and Carpathians as well as southeastern Alps and the Dinaric mountain systems, hereby allowing conclusions on the glacial distribution patterns of these species. Furthermore, genetic analyses of arctic-alpine disjunct species support their broad distribution in the periglacial areas at least during the last glacial period. The detailed understanding of the different phylogeographical structures is essential for the management of the different evolutionary significant units of species and the conservation of their entire genetic diversity. Furthermore, the distribution of genetic diversity due to biogeographical reasons helps understanding the differing regional vulnerabilities of extant populations.     

The effect of ethanol on the formation of N 2-ethylidene-dG adducts in mice: implications for alcohol-related carcinogenicity of the oral cavity and esophagus

The present study aimed to experimentally confirm that long-term alcohol drinking causes a high risk of oral and esophageal cancer in aldehyde dehydrogenase 2 (ALDH2)-deficient individuals. Aldh2 knockout mice, an animal model of ALDH2-deficiency, were treated with 8% ethanol for 14 months. Levels of acetaldehyde-derived DNA adducts were increased in esophagus, tongue and submandibular gland. Our finding that a lack of Aldh2 leads to more DNA damage after chronic ethanol treatment in mice supports epidemiological findings on the carcinogenicity of alcohol in ALDH2-deficient individuals who drink chronically.     

A theropod–sauropod track assemblage from the ?Middle–Upper Jurassic Shedian Formation at Shuangbai,Yunnan Province,China, reflecting different sizes of trackmakers: Review and new observations

A dinosaur tracksite at Hemenkou (Shuangbai County, Yunnan Province) in the ?Middle–Upper Jurassic Shedian Formation that consists mainly of gray-purple feldspathic quartz sandstones was previously reported incorrectly as being in the Lower Cretaceous Puchanghe Formation. The previous assignment is also inconsistent with two regional geological maps. Although mostly yielding poorly preserved tracks, the site nevertheless indicates a diversity of theropod and sauropod trackmakers partly consistent with the Late Jurassic body fossils from the region. Purported ornithopod are re-evaluated here as those of theropods. The theropod tracks and trackways show distinct similarities to those of the Grallator–Eubrontes plexus and can be subdivided into three morphotypes that may reflect different pes anatomy and/or substrate conditions. Two sizes of tracks (small, large) indicate the presence of different size classes or species in this area in the Late Jurassic. Similarly, the sauropod trackways document three differently sized trackmakers (small–medium–large) showing a typical wide-gauge (Brontopodus) pattern. The track record is the first evidence of theropods in the ?Middle–Late Jurassic of central Yunnan, whereas the sauropod tracks suggest a relation to the coeval basal eusauropods known from this region by skeletal remains.     

Influence of aphid–host plant pairs on the survivorship and development of the multicolored Asian ladybird beetle: implications for the management of vegetation in rural landscapes

Although the value of noncrop vegetation for biological control has been extensively studied in agricultural landscapes, there are few reports on how it functions mechanistically. When focusing on the pest control function provided by noncrop vegetation, tritrophic interactions among a predatory natural enemy, its prey, and the prey’s host plant need to be examined. In Japan, the multicolored Asian ladybird beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), an aphidophage, serves as a natural pest control agent in agricultural production, although the species’ introduction into Europe and North America for pest control has had a negative impact on native ecosystems. In the present study, 33 aphid–plant pairs from an agricultural landscape in the eastern Kanto region of Japan were examined experimentally for initial larval survivorship and development of H. axyridis. Significant differences were found among plant–aphid pairs with regard to these parameters. In addition, the larval survivorship of H. axyridis was not consistently determined by host plant or aphid species alone but was context-dependently influenced by the aphid–plant combination. Some alien host plants showed positive effects on the ladybird beetle. Others, however, served as hosts for unsuitable prey species, such as the competitive alien plants Solidago canadensis L. and Robinia pseudoacacia L., which are the host plants of Uroleucon nigrotuberculatum (Olive) and Aphis craccivora Koch, respectively. These findings suggest that various noncrop plants could be managed to promote ladybird beetle populations in rural landscapes.     

Mutation and “Reversion” at the leu-5 locus of Neurospora and its effect on the cytoplasmic and mitochondrial leucyl-tRNA synthetases

The Neurospora mitochondrial and cytoplasmic leucyl-tRNA synthetases differ from each other not only in location but also with respect to tRNA specificity, chromatographic mobility, leucine affinity, and sensitivity to phosphate inhibition. Strain 45208t, which bears a mutation in the leu-5 cistron, produces a cytoplasmic enzyme with reduced affinity for leucine and little if any mitochondrial enzyme activity. Reversion of the 45208t mutation was found to result not only in the reappearance of mitochondrial leucyl-tRNA synthetase activity but also in the production of a cytoplasmic synthetase with an affinity for leucine intermediate between mutant and wild type. The reversion studied, then, did not involve a return to the wild-type nucleotide sequence in the leu-5 cistron. The results obtained lend further support to the conclusion that the leu-5 cistron is involved in specifying, at least in part, the structure of both the cytoplasmic and mitochondrial leucyl-tRNA synthetases, despite the physical and functional differences between them.Research was supported in part by National Science Foundation Grant 27575.     

Examination of the “null” model of connor and simberloff for species co-occurrences on Islands

Summary Among birds of the Bismarck Archipelago, only certain combinations of the species in a guild coexist on islands, and some species that are very similar ecologically have mutually exclusive distributions. Diamond (1975) interpreted these patterns as biologically significant, involving effects such as competition. Connor and Simberloff (1979) claimed such patterns to be not recognizably different from random, because they were scarcely distinguishable from those generated by a null distribution supposedly not incorporating competition.On examining the analysis by Connor and Simberloff, we find that it actually yields the opposite conclusion: three faunas tested have grossly non-random structures, while their test is unworkable for the fourth fauna. The method of Connor and Simberloff for generating a null distribution has many fatal weaknesses: dilution of relevant data from guilds with irrelevant data from the whole species pool; hidden incorporation of effects of competition into the constraints; inability to recognize a checkerboard, the extreme example of a distribution produced by competition; reliance on inefficient Monte Carlo simulations; severe constraints that sometimes make generation of a null distribution impossible; failure to weight species combinations; and failure to identify the direction of non-randomness or the species combinations most responsible.Finally, we use other recent studies by Simberloff and coleagues to examine the value of constructing null hypotheses in community ecology.     

A step on the path in the discovery of new latent fingerprint development reagents: substituted Ruhemann’s purples and implications for the law

Energies corresponding to optimum geometries of ninhydrin, some of its analogs, the corresponding Ruhemann’s Purple analogs and some of the intermediates of the reaction between ninhydrin analogs and amino acids are calculated at Hartree–Fock/6-31G** level of theory. Such a study is significant from a forensic science point of view because of the strong interest in the forensic chemistry and law enforcement communities in developing alternatives to the current generation of ninhydrin-like chemicals for the detection and development of latent fingerprints. In examining our new predictions for the net energetics of the reactions in the formation of substituted Ruhemann’s Purples, we find that a fluorine-containing analog is the most thermodynamically feasible reaction. In light of this finding, we suggest further experimental studies to determine the kinetic feasibility of synthesizing the fluorine-containing analog, as well as other similar molecules and to determine their spectroscopic properties.     

Spacing behaviour and its implications for the mating system of a precocial small mammal: an almost asocial cavyCavia magna ?

Socioecological models for small mammals attempt to explain the causal relations between the spatiotemporal distributions of food resources, females and males. We tested their predictions for a wild population of Cavia magna, a grazing, precocial rodent, by analysing spacing behaviour in relation to various demographic features. Between May 1999 and January 2001 we collected capture-recapture data on 309 individuals and monitored 55 females and 49 males by radiotelemetry in periodically inundated wetland in Uruguay. Cavies showed a nonstationary use of space: monthly home ranges drifted over the whole study site. Female home ranges overlapped with those of several others. Females were randomly distributed and we found no evidence for socially mediated reproductive synchrony. Males ranged over larger areas than females, showing even less site fidelity, and also overlapped with several rivals. This basic spacing system remained stable over a wide range of densities and sex ratios. Independent of sex, animals used overlap zones randomly with respect to each other. Significant dynamic (spatiotemporal) interaction was most frequent between males and females. However, interaction analyses revealed no evidence for stable social bonds between animals, regardless of sex. We suggest that unpredictable female locations prevent males monopolizing females spatially. Because females are solitary, males could monopolize only one female by maintaining close proximity, rendering a roaming mating tactic more successful. Our findings point to a solitary ‘social’ system and overlap promiscuity as the likely mating system for the C. magna population studied. Copyright 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.      

Testing the higher-taxon approach: a case study of aquatic marcophytes in China’s northwest arid zone and its implications for conservation

Assessments of biodiversity are time-consuming and require a high level of expert knowledge. A reduced set of taxonomic ranks other than species has been proved to be useful for rapid and cost-effective assessment of biodiversity. However, few studies have examined how well this method performs for aquatic plant group that of enormous ecological importance. We studied the aquatic plant flora in the arid zone of China and examined whether the distribution of species α- and β-diversity could be predicted well from genus-, and family-levels. Analyses of 3 years field data showed that significant and positive relations exist between α-diversity of species and α-diversity of genera and family in both entire arid zone and five sub-zones. In contrast, β-diversity at species level is difficult to predict from β-diversity indexes at higher taxonomic level. The results indicate that higher-taxon α-diversity, especially at the generic level in our research, can be useful surrogates of species α-diversity for aquatic plants conservation.