bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Effective Interconnectivity of DegraPol-foams Designed for Negative Pressure Wound Therapy
Authors: Milleret Vincent , Bittermann Anne Greet , Mayer Dieter , Hall Heike
Published: March 2009

Many wounds heal slowly and are difficult to manage. Therefore Negative Pressure Wound Therapy (NPWT) was developed where polymer foams are applied and a defined negative pressure removes wound fluid, reduces bacterial burden and increases the formation of granulation tissue. Although NPWT is used successfully, its mechanisms are not well understood. In particular, different NPWT dressings were never compared. Here a poly-ester urethane Degrapol® (DP)-foam was produced and compared with commercially available dressings (polyurethane-based and polyvinyl-alcohol-based) in terms of apparent pore sizes, swelling and effective interconnectivity of foam pores. DP-foams contain relatively small interconnected pores; PU-foams showed large pore size and interconnectivity; whereas PVA-foams displayed heterogeneous and poorly interconnected pores. PVA-foams swelled by 40 %, whereas DP- and PU-foams remained almost without swelling. Effective interconnectivity was investigated by submitting fluorescent beads of 3, 20 and 45 mm diameter through the foams. DP- and PU-foams removed 70-90 % of all beads within 4 h, independent of the bead diameter or bead pre-adsorption with serum albumin. For PVA-foams albumin pre-adsorbed beads circulated longer, where 20 % of 3 mm and 10 % of 20 mm diameter beads circulated after 96 h. The studies indicate that efficient bead perfusion does not only depend on pore size and swelling capacity, but effective interconnectivity might also depend on chemical composition of the foam itself. In addition due to the efficient sieve-effect of the foams uptake of wound components in vivo might occur only for short time suggesting other mechanisms being decisive for success of NPWT.
Grandine A, a New Proaporphine Alkaloid from the Bark of Phoebe grandis
Authors: Mukhtar Mat Ropi , Aziz Ahmad Nazif , Thomas Noel  F. , Hadi A. Hamid A. , Litaudon Marc , Awang Khalijah
Published: March 2009

The stem bark of Phoebe grandis afforded one new oxoproaporphine; (–)-grandine A (1), along with six known isoquinoline alkaloids: (–)-8,9-dihydrolinearisine (2), boldine, norboldine, lauformine, scortechiniine A and scortechiniine B. In addition to that of the new compound, complete 1H- and 13C-NMR data of the tetrahydroproaporphine (–)-8,9-dihydrolinearisine (2) is also reported. The alkaloids’ structures were elucidated primarily by means of high field 1D- and 2D-NMR and HRMS spectral data.
Thermus thermophilus Strains Active in Purine Nucleoside Synthesis
Authors: Almendros Marcos , Gago José-Vicente Sinisterra , Carlos José Berenguer
Published: March 2009

Several strains of Thermus thermophilus were tested in order to detect purine nucleoside synthase activity using pyrimidine nucleosides as the sugar-donor and adenine or hypoxanthine as bases. High productivity values (t =1 hr) were obtained while completely avoiding adenosine-deaminase degradation of the products. N-2-deoxy-ribosyltransferase activity is described for the first time in hyperthermophilic bacteria.
Gene Knockdowns in Adult Animals: PPMOs and Vivo-Morpholinos
Authors: Moulton Jon  D. , Jiang Shan
Published: March 2009

Antisense molecules do not readily cross cell membranes. This has limited the use of antisense to systems where techniques have been worked out to introduce the molecules into cells, such as embryos and cell cultures. Uncharged antisense bearing a group of guanidinium moieties on either a linear peptide or dendrimer scaffold can enter cells by endocytosis and subsequently escape from endosomes into the cytosol/nuclear compartment of cells. These technologies allow systemic administration of antisense, making gene knockdowns and splice modification feasible in adult animals; this review presents examples of such animal studies. Techniques developed with PPMOs, which are an arginine-rich cell-penetrating peptide linked to a Morpholino oligo, can also be performed using commercially available Vivo-Morpholinos, which are eight guanidinium groups on a dendrimeric scaffold linked to a Morpholino oligo. Antisense-based techniques such as blocking translation, modifying pre-mRNA splicing, inhibiting miRNA maturation and inhibiting viral replication can be conveniently applied in adult animals by injecting PPMOs or Vivo-Morpholinos.
New Phenylethanoid Glycosides from the Fruits of Forsythia Suspense (Thunb.) Vahl
Authors: Wang Fu Nan , Ma Zhi Qiang , Liu Ying , Guo Ying Zhi , Gu Zhong Wei
Published: March 2009

Forsythosides H-J (1-3), three new caffeoyl phenylethanoid glycosides (CPGs), were isolated from the fruits of Forsythia suspense (Thunb.) Vahl., together with six known phenylethanoid glycosides: Forsythoside A (4), Forsythoside F (5), Forsythoside E (6), 2-(3,4-dihydroxyphenyl)ethyl-β-D-glucopyranoside (7), phenethyl alcohol β-D-xylo-pyranosyl-(1→6)-β-D-glucopyranoside (8) and calceolarioside B (9). Their structures were determined by spectroscopic and chemical methods.
Metabolic Discrimination of Select List Agents by Monitoring Cellular Responses in a Multianalyte Microphysiometer
Authors: Eklund Sven E. , Thompson Roy G. , Snider Rachel M. , Carney Clare K. , Wright David W. , Wikswo John , Cliffel David E.
Published: March 2009

Harnessing the potential of cells as complex biosensors promises the potential to create sensitive and selective detectors for discrimination of biodefense agents. Here we present toxin detection and suggest discrimination using cells in a multianalyte microphysiometer (MMP) that is capable of simultaneously measuring flux changes in four extracellular analytes (acidification rate, glucose uptake, oxygen uptake, and lactate production) in real-time. Differential short-term cellular responses were observed between botulinum neurotoxin A and ricin toxin with neuroblastoma cells, alamethicin and anthrax protective antigen with RAW macrophages, and cholera toxin, muscarine, 2,4-dinitro-phenol, and NaF with CHO cells. These results and the post exposure dynamics and metabolic recovery observed in each case suggest the usefulness of cell-based detectors to discriminate between specific analytes and classes of compounds in a complex matrix, and furthermore to make metabolic inferences on the cellular effects of the agents. This may be particularly valuable for classifying unknown toxins.
EROD and MROD as Markers of Cytochrome P450 1A Activities in Hepatic Microsomes from Entire and Castrated Male Pigs
Authors: Zamaratskaia Galia , Zlabek Vladimir
Published: March 2009

In the present study, we characterized the kinetic parameters of 7-ethoxy-resorufin O-deethylation (EROD) and 7-methoxyresorufin O-demethylation (MROD) in hepatic microsomes from entire and castrated male pigs. Validation parameters of an HPLC-based method to analyse EROD and MROD activities are also described. Eadie-Hofstee plot analysis demonstrated a biphasic kinetic of EROD, indicating that at least two forms of cytochrome P450 are involved in this reaction. MROD followed monophasic kinetic, suggesting that a single enzyme, or enzymes with similar affinities, is responsible for the reaction. Inhibitory effects of α-naphthoflavone (ANF), ellipticine and furafylline were studied using microsomes from entire and castrated male pigs. ANF is a known inhibitor of both cytochrome P450 1A1 and 1A2 (CYP1A1 and CYP1A2); the presence of ANF in the incubations resulted in the inhibition of both EROD and MROD activities in porcine liver microsomes. EROD activities in porcine liver microsomes were also inhibited by selective CYP1A1 inhibitor ellipticine, but not by CYP1A2 inhibitor furafylline. MROD activities were strongly inhibited by ellipticine and to a much lesser extent by furafylline. Further studies are needed to evaluate substrate specificities of porcine CYP1A1 and CYP1A2.
Electromechanical Characteristic Analysis of Passive Matrix Addressing for Grating Light Modulator
Authors: Jin Zhu , Wen Zhiyu , Zhang Zhihai , Huang Shanglian
Published: March 2009

AGrating Light Modulator (GLM) based on Micro-Electro-Mechanical Systems (MEMS) is applied in projection display. The operating principle of the GLM is introduced in this paper. The electromechanical characteristic of the passive matrix addressing GLM is studied. It was found that if the spring constant is larger, both the response frequency and the driving voltage are larger. Theoretical analysis shows that the operating voltage and the pull-in voltage of the GLM are 8.16 and 8.74 V, respectively. When an all-selected pixel in a m×n array is actuated by a voltage V0, the voltages of the half-selected pixel in row and column are V0(m-1)/(m+n-1) and V0(n-1)/(m+n-1), respectively, and the voltage of the non-selected pixel is V0/(m+n-1). Finally, the experimental results indicate that the operating voltage and the pull-in voltage are 7.8 and 8.5V respectively, and the response frequency of the GLM is about 7 kHz. The crosstalk in a 16×16 GLM array is validated by the experiment. These studies provide a theoretical basis for improving the GLM driver.
Development of a Novel, Ultra-rapid Biosensor for the Qualitative Detection of Hepatitis B Virus-associated Antigens and Anti-HBV, Based on “Membrane-engineered” Fibroblast Cells with Virus-Specific Antibodies and Antigens
Authors: Perdikaris Antonios , Alexandropoulos Nikos , Kintzios Spiridon
Published: March 2009

A novel miniature cell biosensor detection system for the detection of Hepatis B virus (HBV)-associated antigens and anti-HBV is described. The biosensor is based on “membrane-engineered” Vero fibroblast cells immobilized in an alginate matrix. The membrane-engineering process involved the electroinsertion of anti-HBV specific antibodies (anti-HBs, anti-HBe) or antigens (HBsAg) in the membranes of the Vero cells. The attachment of a homologous antigen to the electroinserted antibody (or, respectively, of the antibody to the electroinserted antigen) triggered specific changes to the cell membrane potential that were measured by appropriate microelectrodes, according to the principle of the Bioelectric Recognition Assay (BERA). The sensor was used for screening 133 clinical blood serum samples according to a double-blind protocol. Considerably higher sensor responses were observed against HBV-positive samples, compared with responses against negative samples or samples positive for heterologous hepatitis viruses such as Hepatitis C (HCV) virus. Detection of anti-HBs antibodies was made possible by using a biosensor based on immobilized Vero cells bearing the respective antigen (HBsAg). The observed response was rapid (45 sec) and quite reproducible. Fluorescence microscopy observations showed that attachment of HBV particles to cells membrane-engineered with anti-HBs was associated with a decrease of [Ca2+]cyt. The perspectives for using the novel biosensor as a qualitative, rapid screening, high throughput assay for HBV antigens and anti-HBs in clinical samples is discussed.
Determination of Lactoferrin and Immunoglobulin G in Animal Milks by New Immunosensors
Authors: Campanella Luigi , Martini Elisabetta , Pintore Manuela , Tomassetti Mauro
Published: March 2009

Two different immunosensors, recently developed for the determination of antibacterial proteins (lactoferrin and immunoglobulin G) in buffalo milk and in other commercial animal milks samples, were used in the present study. The aim was to propose these immunosensor methods for routine control of important diet products, such as cow and goat milks, and in particular buffalo milk. To this end we employed two different kinds of immunosensors: one for the analysis of immunoglobulin G (IgG), the other was a new amperometric immunosensor for lactoferrin analysis. Lactoferrin and IgG immunosensors were also used for the determination of lactoferrin and immunoglobulin G in buffalo milk on different days of lactation.
Individual Differences within and across Feedback Suppression Hearing Aids
Authors: Ricketts Todd , Johnson Earl , Federman Jeremy
Published: March 2009

Background: New and improved methods of feedback suppression are routinely introduced in hearing aids; however, comparisons of additional gain before feedback (AGBF) values across instruments are complicated by potential variability across subjects and measurement methods. Purpose:
To examine the variability in AGBF values across individual listeners and an acoustic manikin. Research Design: A descriptive study of the reliability and variability of the AGBF measured within six commercially available feedback suppression (FS) algorithms using probe microphone techniques.
Study Sample: Sixteen participants and an acoustic manikin. Results: The range of AGBF across the six FS algorithms was 0 to 15 dB, consistent with other recent studies. However, measures made in the participants ears and on the acoustic manikin within the same instrument
suggest that across instrument comparisons of AGBF measured using acoustic manikin techniques may be misleading, especially when differences between hearing aids are small (i.e., less than 6 dB). Individual subject results also revealed considerable variability within the same FS algorithms.
The range of AGBF values was as small as 7 dB and as large as 16 dB depending on the specific FS algorithm, suggesting that some models are much more robust than others. Conclusions: These results suggest caution when selecting FS algorithms clinically since different
models can demonstrate similar AGBF when averaging across ears, but result in quite different AGBF values in a single individual ear.
Development and Plasticity of Intra- and Intersensory Information Processing
Authors: Polley Daniel B. , Hillock Andrea R. , Spankovich Christopher , Popescu Maria V. , Royal David W. , Wallace Mark T.
Published: March 2009

The functional architecture of sensory brain regions reflects an ingenious biological solution to the competing demands of a continually changing sensory environment. While they are malleable, they have the constancy necessary to support a stable sensory percept. How does the functional
organization of sensory brain regions contend with these antithetical demands? Here we describe the functional organization of auditory and multisensory (i.e., auditory-visual) information processing in three sensory brain structures: (1) a low-level unisensory cortical region, the primary
auditory cortex (A1); (2) a higher-order multisensory cortical region, the anterior ectosylvian sulcus (AES); and (3) a multisensory subcortical structure, the superior colliculus (SC). We then present a body of work that characterizes the ontogenic expression of experience-dependent influences
on the operations performed by the functional circuits contained within these regions. We will present data to support the hypothesis that the competing demands for plasticity and stability are addressed through a developmental transition in operational properties of functional circuits from
an initially labile mode in the early stages of postnatal development to a more stable mode in the mature brain that retains the capacity for plasticity under specific experiential conditions. Finally, we discuss parallels between the central tenets of functional organization and plasticity
of sensory brain structures drawn from animal studies and a growing literature on human brain plasticity and the potential applicability of these principles to the audiology clinic.
Beyond duplicity and ignorance in global fisheries
Authors: Pauly Daniel
Published: March 2009

The three decades following World War II were a period of rapidly increasing fishing effort and landings, but also of spectacular collapses, particularly in small pelagic fish stocks. This is also the period in which a toxic triad of catch underreporting, ignoring scientific advice and blaming the environment emerged as standard response to ongoing fisheries collapses, which became increasingly more frequent, finally engulfing major North Atlantic fisheries. The response to the depletion of traditional fishing grounds was an expansion of North Atlantic (and generally of northern hemisphere) fisheries in three dimensions: southward, into deeper waters and into new taxa, i.e. catching and marketing species of fish and invertebrates previously spurned, and usually lower in the food web. This expansion provided many opportunities for mischief, as illustrated by the European Union’s negotiated ‘agreements’ for access to the fish resources of Northwest Africa, China’s agreement-fee exploitation of the same, and Japan blaming the resulting resource declines on the whales. Also, this expansion provided new opportunities for mislabelling seafood unfamiliar to North Americans and Europeans, and misleading consumers, thus reducing the impact of seafood guides and similar effort toward sustainability. With fisheries catches declining, aquaculture—despite all public relation efforts—not being able to pick up the slack, and rapidly increasing fuel prices, structural changes are to be expected in both the fishing industry and the scientific disciplines that study it and influence its governance. Notably, fisheries biology, now predominantly concerned with the welfare of the fishing industry, will have to be converted into fisheries conservation science, whose goal will be to resolve the toxic triad alluded to above, and thus maintain the marine biodiversity and ecosystems that provide existential services to fisheries. Similarly, fisheries economists will have to get past their obsession with privatising fisheries resources, as their stated goal of providing the proper incentives to fishers can be achieved without giving away what are, after all, public resources. Overall, the crisis that fisheries are now going through can be seen as an opportunity to renew both their structure—away from fuel-intensive large-scale fisheries—and their governance, and to renew the disciplines which study fisheries, creating a fisheries conservation science in the process. Its greatest achievement will be the creation of a global network of Marine Protected Areas, which, as anticipated by Ramon Margalef, is the way to make controlled exploitation compatible with the continued existence of functioning marine ecosystems.
The effect of sewage discharge on Melarhaphe neritoides (Gastropoda: Littorinidae) population dynamics
Authors: Cabral-Oliveira Joana , Maranhão Paulo , Pardal Miguel Ângelo
Published: March 2009

The discharges of sewage effluent treatment plants has a major impact on coastal communities. In our study area (western coast of Portugal) Melarhaphe neritoides (L. 1758) is the dominant high-shore gastropod. Two populations of M. neritoides were studied in order to understand the impact of sewage discharges on intertidal communities: one population in an impacted area and the other in a similar but unimpacted area (reference site). Environmental data and abundance, biomass, population structure and annual growth production of M. neritoides were estimated in the two areas. The results showed that M. neritoides density is higher in the impacted area as a result of massive settlement. The sewage discharge increases the nutrient concentrations in the water, which causes more microalgae to grow on the rocky surfaces. This higher availability of food may promote recruitment. However, we found high mortality in the juveniles in the impacted area, which affected density values on the upper shore levels (where we found the adults) of both areas. Moreover, the adults were bigger in the unimpacted area, which suggests that individuals grow more or live longer in this area.
Leptostracans (Crustacea: Phyllocarida) from the Ría de Ferrol (Galicia, NW Iberian Peninsula), with description of a new species of Nebalia Leach, 1814
Authors: Moreira Juan , Díaz-Agras Guillermo , Candás María , Señarís Marcos P. , Urgorri Victoriano
Published: March 2009

Knowledge on taxonomy and ecology of leptostracan crustaceans is still scarce in many parts of the world. Sampling in subtidal sediments in the Ria of Ferrol (NW Spain) between 2006 and 2007 yielded several leptostracan specimens belonging to six species. This is, so far, the largest number of leptostracan species reported from a single area. Some specimens belong to an undescribed species of Nebalia Leach, 1814, which is described herein as N. reboredae n. sp. The new species has a rostrum about 2.2 times as long as wide, the antennular scale is slightly more than twice as long as wide, the fourth article of the antennule has one short thick distal spine, the first article of the endopod of the second maxilla is 1.3 times as long as the second one, the exopod of the second maxilla is longer than the first article of the endopod, the posterior dorsal borders of pleonites 5-7 are provided with distally rounded to truncated denticles, and the uropods are as long as pleonite 7 and the anal somite combined. All the species collected are reported, including the number of specimens, sexual condition and substrate type. A key to all known neritic species of the Iberian Peninsula is provided.
The effect of salinity on larval development of Uca tangeri (Eydoux, 1835) (Brachyura: Ocypodidae) and new findings of the zoeal morphology
Authors: Spivak Eduardo D. , Cuesta José A.
Published: March 2009

In order to evaluate their tolerance to low salinities, zoeae of the fiddler crab Uca tangeri from the Rio San Pedro population (southwestern Spain) were reared in the laboratory at 20ºC and at three salinities (16, 24 and 32). The zoeal development was completed at 24 and 32 but the crabs died as zoea I or zoea II, and very rarely as zoea III, at 16; tolerance to low salinities varied among clutches produced by different females. The duration of the first zoeal stage and of the complete zoeal development was shorter at 32. Our observations showed that the zoeae of U. tangeri could not tolerate retention in the mesohaline water of estuaries, and that export to oceanic waters would be optimal for their successful development. Survival at 24 suggests that larvae could also develop in polyhaline conditions if they were retained in the ocean-estuary interface. The presence of an additional zoeal stage (zoea VI) was observed in some individuals and associated with unfavourable combinations of temperature and salinity. In addition, some previously omitted aspects of zoeal morphology were re-described and illustrated, providing new evidence which supports the basal position of this species in a proto-Atlantic origin of the genus Uca. It is proposed that the differences between Uca tangeri and the rest of the Uca species should be highlighted, and that it should be placed in its own genus as Afruca tangeri.
Spatial and temporal patterns of benthic invertebrates in the Tagus estuary, Portugal: comparison between subtidal and an intertidal mudflat
Authors: França Susana , Vinagre Catarina , Pardal Miguel A. , Cabral Henrique N.
Published: March 2009

Intertidal mudflats are a dominant feature in many estuarine systems and may be a significant component of the feeding grounds available for many fish and bird species. Therefore, it is crucial to determine the importance and role that this particular habitat plays for the different estuarine communities. Spatial and temporal dynamics of macrobenthic communities in an intertidal mudflat of the Tagus estuary were assessed in order to determine the role of this habitat in the whole estuarine functioning. Benthic macroinvertebrate communities were sampled monthly in two intertidal areas (upper and lower) and in the adjoining subtidal area for one year. Macroinvertebrate density and biomass in the intertidal mudflat were higher than in the subtidal area, but no clear trends were found between the lower and upper intertidal area. Spatial patterns in the community were more pronounced than seasonal patterns. This benthic community was characterised by high densities of Pygospio elegans, Scrobicularia plana, Cyathura carinata, Hydrobia ulvae and Nereis diversicolor. Abundance and biomass values in this intertidal mudflat were considered low in comparison with other estuarine habitats, namely seagrass beds. Nevertheless, this habitat plays an important role for the main species present in the community, acting as a key area for recruitment, with high concentrations for many invertebrate species.
Age estimation and growth pattern of the island grouper, Mycteroperca fusca (Serranidae) in an island population on the northwest coast of Africa
Authors: Bustos Rocío , Luque Ángel , Pajuelo José G.
Published: March 2009

Mycteroperca fusca is one of the main predators of the Canarian archipelago coastal marine ecosystem. Nothing is known on the life history or population dynamics of this predatory serranid fish. In this study, age and growth of M. fusca were investigated by annual growth increment counts from 214 fish collected between January 2004 and December 2005. A year’s growth is represented by one opaque and one translucent ring. The island grouper is a slow-growing and long-lived species, with ages up to twenty years recorded. Length at age was described by the von Bertalanffy growth model (L∞=898 mm; k=0.062 year-1; and t0= −3.83 year), the Schnute growth model (y1=262 mm; y2=707 mm; a=0.008; and b=1.98), and the seasonalised von Bertalanffy growth model (L∞=908 mm; k=0.061 year-1; t0= −3.83 year; C=2.58; and ts=0.542). Males and females show differences in growth.
Deep-sea meiofaunal and foraminiferal communities along a gradient of primary productivity in the eastern Mediterranean Sea
Authors: Lampadariou Nikolaos , Tselepides Anastasios , Hatziyanni Eleni
Published: March 2009

Benthic metazoa and stained foraminifera (>32 μm) were studied in relation to prevailing environmental parameters in the Aegean Sea (Sporades Basin and Cretan Sea) and Levantine Basin (Ierapetra Basin) during the METEOR Cruise 40 Leg 3 (December 1997–January 1998). The sampling stations differed in nutrient contents, which were indicative of the oligotrophy of the eastern Mediterranean Sea. Meiobenthic abundance decreased significantly with depth and the total standing stock in the top 6 cm sediment layer was significantly higher at the northern stations (204-231 ind./10 cm2). In the abyssal Ierapetra Basin, the abundance for all meiobenthic taxa was minimal (10-26 ind./10 cm2). Nematodes and foraminifera were dominant and accounted together for 79-93% of the total abundance. All taxa were concentrated near the surface of the sediment and only nematodes showed a deeper penetration into the sediments in the Sporades Basin. Concentrations of chloroplastic pigments, total organic carbon and total organic nitrogen were higher in the Sporades and Ierapetra Basins than in the Cretan Sea, reflecting: (a) the different productivity levels and, thus, the higher food availability in the former than in the latter; (b) the seasonal accumulation of organic matter from the euphotic zone down to the abyssal trenches; and (c) the transportation of large amounts of sediment and organic matter in the Sporades and Ierapetra Basins, which are located at the mouth of submarine canyons, through riverine inputs, flush flooding, sediment failure and dense shelf water cascading. Meiofaunal abundances in the Aegean Sea were positively correlated with chlorophyll a, phaeopigments and chloroplastic pigment equivalent (CPE), and were not correlated with any of the remaining sediment descriptors, thus indicating the dependence of meiofauna on food availability.
Morphological variation and a remarkable new sexual dimorphism in the Pseudocyclops xiphophorus population of Lake Faro in northeastern Sicily
Authors: Brugnano Cinzia , Boxshall Geoffrey A. , Costanzo Giuseppe , Zagami Giacomo
Published: March 2009

The population of P. xiphophorus in Lake Faro exhibits variation in the form of caudal seta V. In some specimens of both sexes, this seta is spatulate but in others it is slender and unmodified. Occasional specimens are asymmetrical. In addition to this variation in caudal seta form, the Lake Faro population displays variation in male body length and in the extent of the sexually dimorphic specialisation of the right swimming leg 2. The scale of these differences between the morphotypes might suggest their taxonomic treatment as distinct species. The modification of the distal two segments of the exopod of right leg 2 in the male is a unique sexual dimorphism. We infer, from the presence of this hook on the right exopod in adult males only, that it is involved in mating behaviour. Laboratory-based breeding experiments between females and males showing different combinations of these characters were also performed. Experiments comparing egg production rates in females that have mated with modified or unmodified males revealed no significant differences. It appears therefore that gene flow is not interrupted between the morphotypes and that reproductive segregation does not occur. Observations of male leg 5 morphology and musculature revealed no significant differences between the two P. xiphophorus morphotypes.
Addiction
Authors: Treistman Steven N
Published: March 2009

Addiction includes compulsive seeking of drugs of abuse. These drugs produce positive emotional states following intake, but may lead to negative feelings in their absence. Multiple approaches will be necessary to understand addiction. However, we can assume that part of our understanding will come from exploration of molecules and brain circuitry that predispose to addictive behaviour, and change after drug experimentation. We examine these ideas, focusing on the ‘reward pathway’ in the brain. Addiction studies, in addition to combating a major scourge of society, offer an opportunity to understand mechanisms of neural plasticity important to the brain's ability to learn.

Key Concepts

Addiction refers to compulsive use of a class of drugs known as ‘drugs of abuse’.

The ‘reward pathway’ in the brain is a major target of drugs of abuse.

The initial positive feelings generated by these drugs can diminish with use, and may reduce the reward derived from previously rewarding nondrug experiences.

Addiction can be understood in terms of molecules and brain circuits that may differ in individuals and predispose to addictive behaviour, and may change as a result of drug experimentation, leading to compulsive drug use.

Many of the important issues of neuroscience can be examined within the context of addiction. These include the brain mechanisms of reward, genetic predisposition to behaviours, and neuronal plasticity.
G
Protein‐coupled Receptors
Authors: Bockaert Joël
Published: March 2009

Among membrane‐bound receptors that recognize regulatory messages (hormones, neurotransmitters, photon, odours, etc.) the seven transmembrane receptors (7 TM) coupled to G proteins (G protein‐coupled receptor, GPCRs) are the most numerous. They represent 3% of the total number of genes in human genome. They have similar three‐dimensional (3D) structure but can be grouped into 8 classes that share few sequence similarities. GPCRs are targets for more than 50% of the drugs used in therapy.

Key concepts:

Cell–cell communication involved messages (hormone, neurotransmitter growth factors, odorant, etc.) and receptors, the majority of them being GPCRs.

GPCRs are 7 transmembrane receptors. They form homo‐ or heterodimers.

There are three main classes of GPCRs differing in they primary sequences.

The class 3 is the more original one having it binding site within an extra‐cellular structure called ‘Venus fly trap’.

During evolution mutations have tinkered the GPCR structure in order to allow recognition of ligands as diverse as photon, odorant, sugar, proteins, etc.

Virus like human immunodeficiency virus (HIV) virus use GPCRs such as those recognizing chemokines (CCR5, CXCR3) to enter specialized cells such as macrophages or lymphocytes.

GPCRs are allosteric molecules and drugs can be developed enhancing or silencing the effect of the natural ligand without having any effect by themselves.

Mutations of GPCR are responsible of pathologies. These mutations can render the receptor constitutively active or inactive.
Plant Virus Transmission by Insects
Authors: Raccah B , Fereres A
Published: March 2009

Most plant viruses depend on vectors for their survival and spread. Most vectors are piercing‐sucking insects that transmit plant viruses in either the circulative virus (CV) or noncirculative virus (NCV). NCV are carried on the lining cuticle of vectors stylets. CVs cross the vectors’ gut, move internally to the salivary glands (SG), cross the SG membranes to be ejected upon feeding.

Transmissibility of NCVs depends on motifs of coat protein and for Potyviruses and Caulimoviruses also on helper proteins (encoded by the virus). NCV proteins were found to associate with vectors’ cuticle proteins. Transmissibility of CVs depends on proteins comprising the virus capsid (the coat protein and the read‐through protein) and on symbionin (produced by vectors’ symbionts). Passage of CV through the gut has been also associated with vectors’ proteins.

To suppress plant virus epidemics, several control measures that interfere with vector landing or feeding are proposed.

Key concepts

Plants are rooted; therefore, plant viruses depend for their spread on insect vectors

Epidemics occur when a new virus or a new vector invade a new ecological niche.

Specificity between viruses and vector species may reflect the preference of the vector to the plant species.

Viruses that lost the ability to be transmitted by vectors serve to identify protein motifs that are associated with transmission.

Noncirculative viruses are transmitted by aphids during intracellular stylet penetrations whereas circulative viruses are transmitted during committed phloem ingestion.

Proteins encoded by the potyviruses and caulimoviruses are essential for assisting transmission by aphids.

Heteroencapsidation is responsible for expanding the vector range of luteoviruses.

Vector proteins were found to associate with viral proteins (for potyviruses, caulimoviruses and luteoviruses).

Insecticide are inefficient in preventing noncirculative plant viruses spread by vectors (the time needed to kill the vector is longer than the time needed to inoculate the host).

Control measures that affect vector landing or feeding are efficient in suppressing virus spread.
Small Regulatory
RNAs
in Bacteria
Authors: Delihas Nicholas
Published: March 2009

Intergenic regions of bacteria contain small regulatory
ribonucleic acid
(srRNA) genes whose transcripts control expression of distal genes. These transcripts, referred to here as srRNAs, primarily act at the level of translation where they bind messenger RNAs (mRNAs). srRNAs can inhibit or activate a target mRNA. Base pairing with mRNAs is imperfect and includes looped out and/or bulged nucleotide positions and noncanonical base pairs as well. The RNA chaparone protein Hfq is involved in many RNA/RNA interactions and ribonucleases, RNase E and RNase III, have been implicated in the destabilization of several target mRNAs. Gene transcription can also be controlled by an srRNA via binding to the RNA polymerase–sigma factor complex and blocking a functional site on the enzyme complex. Many srRNA genes are transcriptionally activated by environmental stress factors and have complex promoter and upstream regulatory sites involved in this activation. The control of outer membrane protein synthesis in response to stress is one major function of bacterial srRNAs.

Key Concepts

Properties of small regulatory RNA genes; control of gene expression at the level of translation and transcription by RNA; RNA/RNA interactions; imperfect RNA base pairing and noncanonical base pairs; bacterial cell response to environmental stress conditions; mechanisms of mRNA translational inactivation and degradation; macromolecular responses and phenotypic changes in a cell.
Photosynthesis: The Calvin Cycle
Authors: Heineke Dieter , Scheibe Renate
Published: March 2009

The Calvin cycle is a reductive process in the stroma of chloroplasts responsible for the synthesis of carbohydrates from carbon dioxide. The reactions are organized in a cyclic metabolic pathway that was named after its discoverer Melvin Calvin who received the Nobel Price for Chemistry in 1961. Reducing power in the form of NADPH (nicotinamide‐adenine dinucleotide phosphate reduced form) and energy as adenosine triphosphate (ATP) required for this process are generated in the light reactions located in the thylakoid membrane. Light activation of this process is achieved by covalent redox‐modification of some key enzymes that are inactive in the dark.
Nuclear Envelope and Lamins: Organization and Dynamics
Authors: Liu Jun
Published: March 2009

The nuclear envelope (NE) separates the nucleus and the cytoplasm and plays an important role in the maintenance of nuclear structure. The NE undergoes a complex cycle of assembly and disassembly during cell divisions to allow proper segregation of the chromosomes. Recent advances in basic and clinical research, especially in light of a number of human diseases that are collectively called laminopathies (diseases caused by mutations in A‐typelaminsorlamin‐binding proteins), suggest that the NE not only acts as a structural barrier separating the nuclear genome and transcriptional machinery from the cytoplasm, but also serves as a node that integrates the different structural and signalling networks between the nucleus and the cytoplasm.

Key concepts

There are three structural components of the nuclear envelope: the outer and inner nuclear membranes, the nuclear pore complexes and the nuclear lamina.

The nuclear lamina is mainly composed of type V intermediate filament proteins called lamins, which contain aC‐terminal CAAX motif and undergo extensive post‐translational processing.

Lamins are grouped into A‐ and B‐types based on their sequence homologies, biochemical properties and behaviors during mitosis.

Mutations in LMNA, which encodes the A‐type lamins, cause multiple distinct diseases that are collectively called laminopathies in humans, including diseases of striated muscle, peripheral neuropathy, lipodystrophy syndromes and premature aging or progeroid syndromes.

Lamins exert multiple functions via interacting with various lamin‐binding proteins, including an increasing number of proteins located at the inner nuclear membrane that are retained there because of their interactions with lamin.

The lamin‐binding inner nuclear membrane proteins also function to modulate the output of cell–cell signalling via interacting with transcription factors of different signalling pathways and integrate nuclear and cytoplasmic architecture via the LINC complex (linker of nucleoskeleton and cytoskeleton).

The nuclear pore complexes are large protein assemblies that are organized into structures with eightfold rotational symmetry and serve as gated channels that mediate nucleocytoplasmic transport across the nuclear envelope.

The nuclear envelope undergoes ordered disassembly and assembly during mitosis.

Disassembly of the nuclear envelope during mitosis is caused by the mitotic phosphorylation of nuclear envelope components.

Even during interphase, the nuclear envelope is not static.
Ageing
Authors: Turker Mitchell
Published: March 2009

We will all grow old and die. The question is why. This question is explored from several perspectives, with the caveat that the answer is not known. Evolutionary pressure does not select for ageing of the individual, but we age nonetheless because evolution only selects for reproductive fitness. Our maximum lifespan potential is fixed at approximately 120 years. This does not mean, however, that how we age is immutable because the rate of human ageing has slowed significantly in the last 150 years, at least in some societies. Thus, the goal of ageing research is to allow us to live longer and healthier lives, with the awareness that we will not live forever.

Key Concepts

Ageing is the natural effect of time and the environment on living organisms, with death as the end result.

Ageing and death are not equivalent, but they are often closely related.

Ageing occurs because evolution only selects for reproductive fitness.

Ageing represents a combination of genetic factors, epigenetic factors, environmental exposures and chance.

The rate of ageing has slowed dramatically in the last 150 years.

Better development, including that occurring
in utero
, may lead to better ageing.

Human genetic diseases exist in which one or more aspects of ageing are accelerated.

Somatic mutations increase with age, but whether these mutations play a role in ageing is unclear.

The maximum lifespan potential for humans is approximately 120 years.
Cryptosporidiosis
Authors: Bhaskaran Archana , White A Clinton
Published: March 2009

Cryptosporidiumspp. are protozoans known but the pathogenic role in human infection has been recognized only in the past few decades. Transmission is through the fecal‐oral route, thus poor hygienic practices promotes spread.Cryptosporidiumis not susceptible to disinfectants, including chlorine. Hence transmission via contamination of drinking water can occur unless specific precautions are taken.Cryptosporidiumspp. cause diarrhoea predominantly in children and in immunosupressed individuals. In fact, the greatest burden of disease is among children in developing countries where the parasite is implicated as a cause of persistent diarrhoea and malnutrition in children. The prevalence of this infection is likely underestimated due to limitations in diagnostic testing even in developed countries. Treatment with nitozoxanide achieves cure in children. However results are not less dramatic in individuals with depressed cellular immunity.
Stomata
Authors: Roelfsema M Rob G , Hedrich Rainer
Published: March 2009

Stomata are small adjustable pores on the surface of aerial plant tissues. The pores open to facilitate uptake of carbon dioxide and close to limit the loss of water. Consistent with this function, stomata open in the light to enable photosynthesis and close during drought. Stomatal movements are forced by changes in the volume of two guard cells that are positioned on either side of the pore. During stomatal opening, guard cells accumulate potassium salts, causing an osmotically driven uptake of water. Owing to the influx of water the guard cells swell and bend, thereby pushing each other apart and creating an open pore in the middle. Various environmental signals, such as light, carbon dioxide and humidity, influence the ion‐transport machinery within the guard cell and thus alter stomatal movement. Because of their role in regulating carbon dioxide uptake and transpiration of water, stomata are likely to play a key role in the adaption of plants to the anticipated global warming.

Key concepts

Stomata are small adjustable pores in the leave surface that enable gas exchange.

Open stomata enable the uptake of carbon dioxide for photosynthesis, while closure prevents excessive loss of water during drought.

During evolution, stomata enabled plants to survive in dry environments.

Cell‐to‐cell signalling controls the development of stomata in the leaf surface.

Stomatal movements are forced by two guard cells, surrounding the pore.

Guard cells cause stomata opening through osmotically driven swelling, based on the uptake of K
+
salts.

Environmental signals regulate ion transport in guard cells.

Guard cells sense light with blue light‐sensitive phototropins as well as through changes in the intercellular carbon dioxide concentration.

Drought acts on guard cells via release of the stress hormone abscisic acid.

Stomata are likely to play an important role in the adaption of plants to predicted global changes.
Müller, Johannes Peter (1801–1858)
Authors: Lohff Brigitte
Published: March 2009

In 1819, he started his medical studies at the University of Bonn in Germany. In 1826, he formulated the
Law of Specific Sense Energy
. With his anatomical and physiological research he became one of the most important scientists of life sciences in Europe. Since 1833 until his death, he was director of the Institute of Anatomy and Physiology at the University of Berlin. He mainly worked in the field of sensory, haematological, pathological anatomy and physiology as well as systematic zoology and marine biology. Müller's exceptional position in the history of medicine and zoology was not only connected with his own research, but was also due to his epistemological reflections on scientific physiology and experimental medicine and his role as an influential and important teacher.
Gene Expression in Yeast
Authors: Scheiner‐Bobis Georgios
Published: March 2009

In the past few decades expression of foreign genes in yeast has not only been a very powerful tool for analysing and understanding protein function within the framework of scientific investigations, it also has become a major economic factor of the biotechnological industries. The article presented here deals with well‐established methods and strategies for ensuing reliable transfer of foreign genes and sustained protein production in yeast.
Discrimination in Insurance: Experience in the United States
Authors: Hall Mark A
Published: March 2009

Health and life insurers may wish to discriminate based on genetic information by classifying people as high risk or unhealthy based on genetic tests that predict future health problems, rather than on diagnosis of current illness. In the USA, the fear of genetic discrimination by insurers is much greater than the reality, especially for health insurance. The economics of health insurance makes it unlikely that health insurers will want to consider purely predictive genetic information, and there are ample legal threats to keep this possibility from materializing, including the 2008 Genetic Information Nondiscrimination Act. Empirical studies consistently document the virtual absence of any genetic discrimination by health insurers. Life insurers are more likely to consider results from predictive genetic tests, but this practice currently is not widespread.
Craniofacial Defects and Cleft Lip and Palate
Authors: Thomason Helen A , Dixon Michael J
Published: March 2009

Craniofacial abnormalities are common and distressing birth defects which result from abnormalities of neural crest cell ontogeny and abnormal growth or fusion of the facial processes, palatal shelves or cranial sutures. These defects may result from mutations in a single gene or through a combination of genetic and environmental factors. The increasing availability of genetically modified mice that exhibit craniofacial abnormalities together with expression analyses has played, and will continue to play, an important role in identifying candidate genes for craniofacial abnormalities.