Bluemel, Joanna K.; Bunbury, Nancy; Curran, Melinda
Ligia isopods are conspicuous inhabitants of rocky intertidal habitats exhibiting several biological traits that severely limit their dispersal potential. Their presence in patchy habitats and low vagility may lead to long term isolation, allopatric isolation and possible cryptic speciation. Indeed, various species of Ligia have been suggested to represent instead cryptic species complexes. Past studies; however, have largely focused in Eastern Pacific and Atlantic species of Ligia, leaving in doubt whether cryptic diversity occurs in other highly biodiverse areas. The Seychelles consists of 115 islands of different ages and geological origins spread across the western Indian Ocean. They are well known for their rich biodiversity with recent reports of cryptic species in terrestrial Seychellois organisms. Despite these studies, it is unclear whether coastal invertebrates from the Seychelles harbor any cryptic diversity. In this study, we examined patterns of genetic diversity and isolation within Ligia isopods across the Seychelles archipelago by characterizing individuals from locations across both inner and outer islands of the Seychelles using mitochondrial and nuclear markers. We report the presence of highly divergent lineages of independent origin. At Aldabra Atoll, we uncovered a lineage closely related to the Ligia vitiensis cryptic species complex. Within the inner islands of Cousine, Silhouette, and Mahé we detected the presence of two moderately divergent and geographically disjunct lineages most closely related to Ligia dentipes. Our findings suggest that the Seychelles may harbor at least three novel species of Ligia in need of description and that these species may have originated independently. PMID:29018626
Ruck, Philip; Jahn, Theodore L.
The ERG of the compound eye in freshly collected Ligia occidentalis, in response to high intensity light flashes of ⅛ second or longer duration, begins with a negative on-effect quickly followed by an early positive deflection, rapidly returns to the baseline during illumination, and ends with a positive off-effect. As the stimulus intensity is decreased the early positivity progressively decreases and the rapid return to the baseline is replaced by a slowing decline of the negative on-effect. Responses were recorded with one active electrode subcorneally situated in the illuminated eye, the reference electrode in the dark eye. The dark-adapted eye shows a facilitation of the amplitude and rates of rise and fall of the on-effect to a brief, high intensity light stimulus. This facilitation may persist for more than 2 minutes. Following light adaptation under conditions in which the human eye loses sensitivity by a factor of almost 40,000 the Ligia eye loses sensitivity by a factor of only 3. The flicker fusion frequency of the ERG may be as high as 120/second with a corneal illumination of 15,000 foot-candles. Bleeding an otherwise intact animal very rapidly results in a decline of amplitude, change of wave form, and loss of facilitation in the ERG. When the eye is deganglionated without bleeding the animal the isolated retina responds in the same manner as the intact eye. Histological examination of the Ligia receptor layer showed that each ommatidium contains three different retinula cell types, each of which may be responsible for a different aspect of the ERG. PMID:13174786
Ziegler, Andreas; Hagedorn, Monica; Ahearn, Gregory A; Carefoot, Thomas H
Terrestrial isopods moult first the posterior and then the anterior half of the body. During the moulting cycle they retain a significant fraction of cuticular calcium partly by storing it in sternal CaCO(3) deposits. We analysed the calcium content in whole Ligia hawaiiensis and the calcium distribution between the posterior, the anterior ventral, and the anterior dorsal cuticle during four stages of the moulting cycle. The results indicate that: (1) overall, about 80% of the calcium is retained and 20% is lost with the exuviae, (2) in premoult 68% of the calcium in the posterior cuticle is resorbed (23% moved to the anterior ventral cuticle, 17% to the anterior dorsal cuticle, and the remaining 28% to internal tissues), (3) after the posterior moult 83% of the calcium in the anterior cuticle is shifted to the posterior cuticle and possibly to internal storage sites, (4) following the anterior moult up to 54% of the calcium in the posterior cuticle is resorbed and used to mineralise the new anterior cuticle. (45)Ca-uptake experiments suggest that up to 80% of calcium lost with the anterior exuviae may be regained after its ingestion. Whole body calcium of Ligia hawaiiensis is only 0.7 times that of the fully terrestrial isopods. These terrestrial species can retain only 48% of whole body calcium, suggesting that the amount of calcium that can be retained by shifting it between the anterior and posterior integument is limited. We propose that fully terrestrial Oniscidea rely to a larger degree on other calcium sources like internal stores and uptake from the ingested exuviae.
Hurtado, Luis A; Mateos, Mariana; Wang, Chang; Santamaria, Carlos A; Jung, Jongwoo; Khalaji-Pirbalouty, Valiallah; Kim, Won
The native ranges and invasion histories of many marine species remain elusive due to a dynamic dispersal process via marine vessels. Molecular markers can aid in identification of native ranges and elucidation of the introduction and establishment process. The supralittoral isopod Ligia exotica has a wide tropical and subtropical distribution, frequently found in harbors and ports around the globe. This isopod is hypothesized to have an Old World origin, from where it was unintentionally introduced to other regions via wooden ships and solid ballast. Its native range, however, remains uncertain. Recent molecular studies uncovered the presence of two highly divergent lineages of L. exotica in East Asia, and suggest this region is a source of nonindigenous populations. In this study, we conducted phylogenetic analyses (Maximum Likelihood and Bayesian) of a fragment of the mitochondrial 16S ribosomal (r)DNA gene using a dataset of this isopod that greatly expanded previous representation from Asia and putative nonindigenous populations around the world. For a subset of samples, sequences of 12S rDNA and NaK were also obtained and analyzed together with 16S rDNA. Our results show that L. exotica is comprised of several highly divergent genetic lineages, which probably represent different species. Most of the 16S rDNA genetic diversity (48 haplotypes) was detected in East and Southeast Asia. Only seven haplotypes were observed outside this region (in the Americas, Hawai'i, Africa and India), which were identical or closely related to haplotypes found in East and Southeast Asia. Phylogenetic patterns indicate the L. exotica clade originated and diversified in East and Southeast Asia, and only members of one of the divergent lineages have spread out of this region, recently, suggesting the potential to become invasive is phylogenetically constrained.
Kilpert, Fabian; Podsiadlowski, Lars
Background Sequence data and other characters from mitochondrial genomes (gene translocations, secondary structure of RNA molecules) are useful in phylogenetic studies among metazoan animals from population to phylum level. Moreover, the comparison of complete mitochondrial sequences gives valuable information about the evolution of small genomes, e.g. about different mechanisms of gene translocation, gene duplication and gene loss, or concerning nucleotide frequency biases. The Peracarida (gammarids, isopods, etc.) comprise about 21,000 species of crustaceans, living in many environments from deep sea floor to arid terrestrial habitats. Ligia oceanica is a terrestrial isopod living at rocky seashores of the european North Sea and Atlantic coastlines. Results The study reveals the first complete mitochondrial DNA sequence from a peracarid crustacean. The mitochondrial genome of Ligia oceanica is a circular double-stranded DNA molecule, with a size of 15,289 bp. It shows several changes in mitochondrial gene order compared to other crustacean species. An overview about mitochondrial gene order of all crustacean taxa yet sequenced is also presented. The largest non-coding part (the putative mitochondrial control region) of the mitochondrial genome of Ligia oceanica is unexpectedly not AT-rich compared to the remainder of the genome. It bears two repeat regions (4× 10 bp and 3× 64 bp), and a GC-rich hairpin-like secondary structure. Some of the transfer RNAs show secondary structures which derive from the usual cloverleaf pattern. While some tRNA genes are putative targets for RNA editing, trnR could not be localized at all. Conclusion Gene order is not conserved among Peracarida, not even among isopods. The two isopod species Ligia oceanica and Idotea baltica show a similarly derived gene order, compared to the arthropod ground pattern and to the amphipod Parhyale hawaiiensis, suggesting that most of the translocation events were already present the last common
Quinn, Todd; Benedict, Karl; Dickey, Jeff
In 1877 a small group of Swiss immigrants from the Graubunden canton formed a cooperative with another Swiss group in Stillwater, Minnesota, to begin a colony in eastern South Dakota. These settlers founded the Badus Swiss colony on the open prairie in Lake County, Dakota Territory (later South Dakota), based on cooperative rules written in…
Words or names preceded by a ques - tion mark and enclosed in parentheses were not clear in the original but have been supplied as appropriate in...Alexandra Dinulescu; AGRICULTURA SOCIALISTA, 21 May 77) 54 Job Training Planned for All Cooperative Workers (Gheorghe Cristea; AGRICULTURA SOCIALISTA...9 Apr 77). 58 Modernization of Commercial Activity Necessary (Gh. Feteanu; AGRICULTURA SOCIALISTA, 7 May 77) 62 YUGOSLAVIA Law on Foreign
Hurtado, Luis A.; Lee, Eun Jung; Mateos, Mariana
Phylogeographic studies of animals with low vagility and restricted to patchy habitats of the supralittoral zone, can uncover unknown diversity and shed light on processes that shaped evolution along a continent’s edge. The Pacific coast between southern California and central Mexico, including the megadiverse Gulf of California, offers a remarkable setting to study biological diversification in the supralittoral. A complex geological history coupled with cyclical fluctuations in temperature and sea level provided ample opportunities for diversification of supralittoral organisms. Indeed, a previous phylogeographic study of Ligia, a supralittoral isopod that has limited dispersal abilities and is restricted to rocky patches, revealed high levels of morphologically cryptic diversity. Herein, we examined phylogeographic patterns of Tylos, another supralittoral isopod with limited dispersal potential, but whose habitat (i.e., sandy shores) appears to be more extensive and connected than that of Ligia. We conducted Maximum Likelihood and Bayesian phylogenetic analyses on mitochondrial and nuclear DNA sequences. These analyses revealed multiple highly divergent lineages with discrete regional distributions, despite the recognition of a single valid species for this region. A traditional species-diagnostic morphological trait distinguished several of these lineages. The phylogeographic patterns of Tylos inside the Gulf of California show a deep and complex history. In contrast, patterns along the Pacific region between southern California and the Baja Peninsula indicate a recent range expansion, probably postglacial and related to changes in sea surface temperature (SST). In general, the phylogeographic patterns of Tylos differed from those of Ligia. Differences in the extension and connectivity of the habitats occupied by Tylos and Ligia may account for the different degrees of population isolation experienced by these two isopods and their contrasting phylogeographic
Gregory, Ligia C. Christi and Ganesh N. Raikar vin LDEF EXPERIMENT AO034: ATOMIC OXYGEN STIMULATED OUTGAS SING 763 Roger C. Linton, Rachel R. Kamenetzky...A 8/27/90 1 Micron Stylus Radius 1 Mg Stylus Loading rW^wV^WvANw/VW^ W ,’"’’M’*****W^^ 150 SCRN LENGTH (microns) 350 4E 450^ e £00...4-^ 4-5 rt3-t- CL S-4-J «J ~CJ +J U ^’ CO V> 3 ! T3 XS -O <: c: 3 c o O 00 o 5* CO <JS ?*ssasssBsss;;>s!ss
Ishii, Daisuke; Horiguchi, Hiroko; Hirai, Yuji; Yabu, Hiroshi; Matsuo, Yasutaka; Ijiro, Kuniharu; Tsujii, Kaoru; Shimozawa, Tateo; Hariyama, Takahiko; Shimomura, Masatsugu
Some small animals only use water transport mechanisms passively driven by surface energies. However, little is known about passive water transport mechanisms because it is difficult to measure the wettability of microstructures in small areas and determine the chemistry of biological surfaces. Herein, we developed to directly analyse the structural effects of wettability of chemically modified biological surfaces by using a nanoliter volume water droplet and a hi-speed video system. The wharf roach Ligia exotica transports water only by using open capillaries in its legs containing hair- and paddle-like microstructures. The structural effects of legs chemically modified with a self-assembled monolayer were analysed, so that the wharf roach has a smart water transport system passively driven by differences of wettability between the microstructures. We anticipate that this passive water transport mechanism may inspire novel biomimetic fluid manipulations with or without a gravitational field.
Alagboso, Francisca I; Reisecker, Christian; Hild, Sabine; Ziegler, Andreas
The cuticle of the cornea in Crustacea is an interesting example of a composite material compromising between two distinct functions. As part of the dioptric apparatus of the ommatidia within the complex eye it forms transparent micro-lenses that should as well maintain the mechanical stability of the head capsule. We analyzed the ultrastructure and composition of the isopod cornea cuticle of the terrestrial species Ligia oceanica and the marine Sphaeroma serratum. We used a variety of tissue preparation methods, electron microscopic techniques as well as electron microprobe analysis and Raman spectroscopic imaging. The results reveal various structural adaptations that likely increase light transmission. These are an increase in the thickness of the epicuticle, a reduction of the thickness of the outer layer of calcite, a spatial restriction of pore canals to interommatidial regions, and, for S. serratum only, an increase in calcite crystal size. In both species protein-chitin fibrils within the proximal exocuticle form a peculiar reticular structure that does not occur within the cuticle of the head capsule. In L. oceanica differential mineralization results in a spherically shaped interface between mineralized and unmineralized endocuticle, likely an adaptation to increase the refractive power of the cornea maintaining the mechanical stability of the cuticle between the ommatidia. The results show that the habitat and differences in the general structure of the animal's cuticle affect the way in which the cornea is adapted to its optical function. Copyright © 2014 Elsevier Inc. All rights reserved.
Owens, Otis L; Beer, Jenay M; Reyes, Ligia I; Gallerani, David G; Myhren-Bennett, Amanda R; McDonnell, Karen K
Up to 70% of lung cancer survivors are affected by chronic obstructive pulmonary disease (COPD), a common, debilitating, comorbid disease. Lung cancer and COPD are both characterized by symptoms such as breathlessness, fatigue, and psychological distress. These distressing chronic symptoms are exacerbated by stress and detract from an individual's quality of life. The aim of this study was to identify and evaluate evidence-based, commercially available apps for promoting mindfulness-based strategies among adults with a COPD or lung cancer history (ie, chronic lung disease). For this review, an interdisciplinary research team used 19 keyword combinations in the search engines of Google and iOS app stores in May 2017. Evaluations were conducted on the apps' (1) content, (2) usability heuristics, (3) grade-level readability, and (4) cultural sensitivity. The search resulted in 768 apps (508 in iOS and 260 in Google stores). A total of 9 apps met the inclusion criteria and received further evaluation. Only 1 app had below an eighth-grade reading level; the ninth one did not have enough text to calculate a readability score. None of the 9 apps met the cultural sensitivity evaluation criteria. This systematic review identified critical design flaws that may affect the ease of using the apps in this study. Few mobile apps promote mindfulness-based strategies among adults with chronic lung disease (ie, COPD or lung cancer or both), but those that exist, overall, do not meet the latest scientific evidence. Recommendations include more stringent regulation of health-related apps, use of evidence-based frameworks and participatory design processes, following evidence-based usability practices, use of culturally sensitive language and images, and ensuring that content is written in plain language. ©Otis L Owens, Jenay M Beer, Ligia I Reyes, David G Gallerani, Amanda R Myhren-Bennett, Karen K McDonnell. Originally published in JMIR Mhealth and Uhealth (http
Nakamura, Maya; Wright, Jonathan C
A key evolutionary development facilitating land colonization in terrestrial isopods (Isopoda: Oniscidea) is the intermittent liberation of waste nitrogen as volatile ammonia. Intermittent ammonia release exploits glutamine (Gln) as an intermediary nitrogen store. Here, we explore the relationship between temporal patterns of ammonia release and Gln accumulation in three littoral oniscideans from Southern California. Results are interpreted in terms of water availability, habitat, activity patterns, and ancestry. A two-way experimental design was used to test whether ammonia excretion and Gln accumulation follow a tidal or diel periodicity. Ammonia excretion was studied in the laboratory using chambers with or without available seawater and using an acid trap to collect volatile ammonia. Ligia occidentalis releases ammonia directly into seawater and accumulates Gln during low tide (48.9 ± 6.5 μmol g⁻¹ at low tide, 24.1 ± 3.0 μmol g⁻¹ at high tide), indicating that excretion is tidally constrained. Alloniscus perconvexus and Tylos punctatus can excrete ammonia directly into seawater or utilize volatilization. Both species burrow in sand by day and show a diel excretory pattern, accumulating Gln nocturnally (31.8 ± 2.7 μmol g⁻¹ at dawn and 21.8 ± 2.3 μmol g⁻¹ at dusk for A. perconvexus; 85.7 ± 15.1 μmol g⁻¹ at dawn and 25.4 ± 2.9 μmol g⁻¹ at dusk for T. punctatus) and liberating ammonia diurnally. Glutaminase shows higher activity in terrestrial (0.54-0.86 U g⁻¹) compared to intertidal (0.25-0.31 U g⁻¹) species, consistent with the need to generate high PNH₃ for volatilization. The predominant isoform in Armadillidium vulgare is phosphate dependent and maleate independent; phosphate is a plausible regulator in vivo.
Cha, Jae-Hoon; Kim, Kwang-Bae; Song, Ji-Na; Kim, In-Soo; Seo, Jeong-Bin; Kwoun, Chul-Hwi
This study was carried out to learn about differences in the sessile macrobenthic fauna communities between the artificial and natural habitats. There were some differences in terms of species composition and dominant species and community structure between two habitat types. The dominant species include Pollicipes mitella and Granuilittorina exigua in natural rocky intertidal zones; Monodonta labio confusa, Ligia exotica, Tetraclita japonica in the artificial rocky intertidal zones. Among all the species, L. exotica and T. japonica occurred only in the artificial rocky intertidal zone. The results of cluster analysis and nMDS analysis showed a distinct difference in community structure between artificial and natural rocky intertidal zones. The fauna in the natural rocky intertidal zones were similar to each other and the fauna in the artificial rocky intertidal zones were divided depending on the slope of the substratum. In the case of a sloping tetrapod, M. labio confusa and P. mitella were dominant, but at the vertical artificial seawall, Cellana nigrolineata, L. exotica T. japonica were dominant. The analysis of the species presented in natural and artificial rocky intertidal areas showed the exclusive presence of 10 species on natural rocks and 12 species on artificial rocks. The species in the natural rocky intertidal area included mobile gastropods and cnidarians (i.e. rock anemones), and the species in the artificial rocky intertidal area mostly included non-mobile attached animals. The artificial novel structure seems to contribute to increasing the heterogeneity of habitats for marine invertebrate species and an increase the species diversity in rocky coastal areas.
Zhang, Melvyn; Ying, JiangBo; Song, Guo; Fung, Daniel Ss; Smith, Helen
Cognitive biases refer to automatic attentional and interpretational tendencies, which could be retained by cognitive bias modification interventions. Cristea et al and Jones et al have published reviews (in 2016 and 2017 respectively) on the effectiveness of such interventions. The advancement of technologies such as electronic health (eHealth) and mobile health (mHealth) has led to them being harnessed for the delivery of cognitive bias modification. To date, at least eight studies have demonstrated the feasibility of mobile technologies for the delivery of cognitive bias modification. Most of the studies are limited to a description of the conventional cognitive bias modification methodology that has been adopted. None of the studies shared the developmental process for the methodology involved, such that future studies could adopt it in the cost-effective replication of such interventions. It is important to have a common platform that could facilitate the design and customization of cognitive bias modification interventions for a variety of psychiatric and addictive disorders. It is the aim of the current research protocol to describe the design of a research platform that allows for customization of cognitive bias modification interventions for addictive disorders. A multidisciplinary team of 2 addiction psychiatrists, a psychologist with expertise in cognitive bias modification, and a computer engineer, were involved in the development of the intervention. The proposed platform would comprise of a mobile phone version of the cognitive bias task which is controlled by a server that could customize the algorithm for the tasks and collate the reaction-time data in realtime. The server would also allow the researcher to program the specific set of images that will be present in the task. The mobile phone app would synchronize with the backend server in real-time. An open-sourced cross-platform gaming software from React Native was used in the current development
Maftei, R.-M.; Ciurean, R.; Scutelnicu, I.; Cristea, P.; Manj, V.; Rusu, E.; Grigorescu, A.; Avram, O.; Cristian, C.
Methodology for natural and antropical hazards' assessment regarding land instability phenomena-case studies in Romania Raluca Maftei, Roxana Ciurean, Ionut Scutelnicu, Paul Cristea, Valeriu Manj, Emil Rusu, Andrei Grigorescu, Ovidiu Avram, Cristina Cristian (1) (1) Geological Institute of Romania, Bucharest, Romania This paper is seeking to launch and to integrate data acquiring and processing technologies, technologies that are subordinated to geological and geophysical techniques, for the evaluation of land properties and of the state of land degradation in areas where natural and antropical hazards related to shallow layers' dynamics are probable. Since evaluating and diminishing land degradation process due to landslides ( took as in its extensive meaning) demand data regarding physical and geological characteristics of the lithologic complexes implied, the project has as a main objective to increase the possibility for the principal geophysical methods of shallow land layers' resolute investigation ( seismometry, electrometry). In Romania, in 2001, law 575 was adopted: ‘‘Law regarding the approval of the Plan for the national territory fitting out- Section V- Natural risk areas''. It mentions that a Romania "Landslides Risk Map" should be edited. In these circumstances, in order to establish the potential and the probability for an area to be affected by soil instability phenomenon ( caused by natural or antropical factors), according to the COM 232/2006, Chapter 2, Section 1, Article 6, the first step that has to be made is to identify and classify risk areas from the studied region. The region will than be verified every 10 years and the measure taking program will than be made public and revised every 5 years. Areas affected by landslides can loose the following functions ( COM 232/2006, chapter 1, article 1): Soil functions Bio-mass production Accumulation, filtering and transforming Biodiversity Physical and cultural environment Raw materials Carbon
Testimony is a complex act that contributes significantly to the elaboration of mourning, both individually and on a collective level. This is the central idea that is discussed in the text, using as a basis, the results of research conducted as a pilot intervention in the year 2010 for Visible Victims Foundation, and was then replicated in four other regions. In 1998 the National Liberation Army attacked the pipeline OCENSA causing severe damage to the people of Machuca (Segovia, Antioquia). In 2010 the psychologist Ligia Rascovsky implemented an intervention strategy to support the construction of individual and collective memory among survivors of the attack, who, in addition to serious injuries, suffered physical and psychosocial after effects such as post-traumatic stress disorder (PTSD). The results of this work are used to understand the relevance of the testimony in the psychosocial recovery processes, which is a major challenge for Colombian society today. The type of study was psychosocial intervention in 43 adults of both sexes, Machuca residents who were affected by the bombing, and agreed to voluntarily participate in designed workshops. The workshops followed experiential type techniques (psychodrama, psycho-fantasies, etc.), in which the purpose was to identify the damage by developing testimonial memory of what happened. The workshops express the emotions of grief, recognize the injustice of suffering, fight memory defense that justifies violence and raising awareness of human rights. It also facilitated the process of dignity, empowerment and security in personal and collective reconstruction. In expressing their memoirs thus, they could be free from fear and gain more confidence in themselves as individuals and as a social group, as seen in the formation of individual leadership. These results are the basis of the discussion presented. In this context it has been found that the testimonial narrative is an instrument of personal and social healing
Maftei, Raluca-Mihaela; Rusu, Emil; Cristea, Paul; Manj, Valeriu; Avram, Ovidiu; Tudor, Elena; Porumbescu, Constantina; Ciurean, Roxana
New results concerning geophysical and geological-engineering data. Case study Telega, Romania R.Maftei, E.Rusu, P.Cristea, V.Manj, R.Ciurean, O.Avram, E.Tudor, C.Porumbescu Geological Institute of Romania, Geohazard, Bucharest, Romania (email@example.com) Geophysical tests The geoelectric investigation (October-November 2009) outlines horizontally the sliding area, and vertically the elements of the landslide surface - position, depth, shape, and the bedrock's relief. The quantitative interpretation of the resistivity geoelectrical vertical tests, and the correlation with the geological structure identified 3 sliding surfaces, from which only the upper one (2-6m depth) was known before the stability works. There were localized the rainfall waters circulation and accumulation zones, areas with high sliding risk. Same results were obtained in sliding zones, been localized the principal elements of the landslides, with practical implications in land instability and estimation of the evolution of the destructive phenomena mechanisms. With this study we try to quantify the complex relationship between the natural factors that generate the terrain instability phenomena and the intensity of the socio-economic effects, at a regional and local scale, by correlating the engineering geology information and geophysical data. Recent seismic research program (September 2009) conceived for "La Butoi" landslide, Telega locality, aims to a specific monitoring of the dynamic deformations, more active in the central part of the landslide, with reference to the shallow seismic refraction information obtained in the 2004 - 2005 period. The investigations were performed on a seismic lines network, and two seismic boundaries, in the shallow seismic section, were exhibited. As a result, one can observe the curvature tendency of the first arrivals sin-phase for the end-off shot devices, setting off the velocity increasing regime with depth; relative high variations and irregularities of