bluuebunny/crossref_metadata_2025 huggingface dataset:
Contrasting Parental Tasks Influence Parental Roles for Paired and Single Biparental Cichlid Fish
Authors: Snekser Jennifer L. , Itzkowitz Murray
Published: February 2014

Biparental care of young occurs when both parents provide some sort of care for offspring and can include a wide variety of behaviors, yet often studies focus on single aspects of parental care when trying to determine how each parent contributes. Here, we presented the biparental convict cichlid fish (Amatitlania nigrofasciata) with two conflicting parental behaviors: retrieval of non‐swimming offspring that have been displaced from the nest and defense against a conspecific intruder, a potential brood predator. We examined single males, single females, and pairs of parents to determine how males and females each contributed to overall parental care. Traditionally in this species, parents exhibit a division of labor (in which each parent contributes to all parental activities), but also exhibit a division of roles (in which males tend to favor the role of defense and females tend to favor more direct care, spending more time with offspring). We hypothesized that single parents would compensate for their absent mate, but that males and females would still favor preferred roles. Additionally, we hypothesized that there would be an asymmetrical expansion of roles, with females being more flexible. Our results show that the preferred roles of both parents were evident even when parents were without their mates and that males and females differed in their compensatory levels, at least when compared to the behaviors of the intact pair. Contrary to our prediction, females seem unable to fully compensate for the defensive behaviors usually exhibited by males, while males shifted completely to retrieve displaced offspring.
The GAR domain of GAS2L3 mediates binding to the chromosomal passenger complex and is required for localization of GAS2L3 to the constriction zone during abscission
Authors: Fackler Marc , Wolter Patrick , Gaubatz Stefan
Published: February 2014

GAS2L3 is a recently identified tubulin‐ and actin‐binding protein that regulates cytokinesis and abscission. In this study we show that GAS2L3 interacts with the chromosomal passenger complex (CPC), which plays key roles in mitosis and cytokinesis. Biochemical assays show that GAS2L3 directly interacts with the C‐terminus of borealin and the N‐terminus of survivin. We find that the interaction between these two CPC subunits and GAS2L3 is mediated by the conserved GAR domain of GAS2L3. We further show that the GAR domain of GAS2L3 is required for localization of GAS2L3 to the constriction zone. Taken together these data suggest that GAS2L3 is a downstream effector of the CPC during cytokinetic abscission.
Influence of ocean and freshwater conditions on Columbia River sockeye salmon Oncorhynchus nerka adult return rates
Authors: Williams John G. , Smith Steven G. , Fryer Jeffrey K. , Scheuerell Mark D. , Muir William D. , Flagg Tom A. , Zabel Richard W. , Ferguson John W. , Casillas Edmundo
Published: February 2014

In recent years, returns of adult sockeye salmon Oncorhynchus nerka to the Columbia River Basin have reached numbers not observed since the 1950s. To understand factors related to these increased returns, we first looked for changes in freshwater production and survival of juvenile migrants. We then evaluated productivity changes by estimating smolt‐to‐adult return rates (SAR) for juvenile migration years 1985–2010. We found SAR varied between 0.2 and 23.5%, with the highest values coinciding with recent large adult returns. However, the largest adult return, in 2012, resulted not from increased survival, but from increased smolt production. We evaluated 19 different variables that could influence SARs, representing different facets of freshwater and ocean conditions. We used model selection criteria based on small‐sample corrected AIC to evaluate the relative performance of all two‐ and three‐variable models. The model with April upwelling, Pacific Northwest Index (PNI) in the migration year, and PNI in the year before migration had 10 times the AICc weight as the second‐best‐supported model, and R2 = 0.82. The variables of April ocean upwelling and PNI in the migration year had high weights of 0.996 and 0.927, respectively, indicating they were by far the best of the candidate variables to explain variations in SAR. While our analyses were primarily correlative and limited by the type and amount of data currently available, changes in ocean conditions in the northern California Current system, as captured by April upwelling and PNI, appeared to play a large role in the variability of SAR.
Increased activity and growth rate in the non‐dispersive aquatic larval stage of a damselfly at an expanding range edge
Authors: Therry Lieven , Lefevre Evelien , Bonte Dries , Stoks Robby
Published: February 2014

While evolutionary changes in adult traits during range expansion have been recorded in many species, similar changes in the non‐dispersive larval stage have only rarely been documented. Increased activity in the non‐dispersive larval stage is an important ecologically relevant trait in aquatic communities that may be expected to evolve in the edge populations (i) as a result of the combination of spatial sorting in dispersal‐related adult activity and a coupling between adult and larval behaviour and (ii) to meet higher energy demands to allow higher growth rates and a higher investment in costly dispersal‐related traits.

We specifically address whether activity is higher in the larval non‐dispersive aquatic stage at an expanding range front by comparing larvae of replicated core and edge populations of the damselfly Coenagrion scitulum in three common garden experiments where larvae were reared from the egg stage.

As expected, activity in the non‐dispersive larval stage was consistently higher in the edge populations. Although changes in larval activity probably have consequences for ecological interactions, the higher activity was not associated with increased predation rates by dragonfly larvae, potentially because of associated compensatory changes in other antipredator mechanisms.

We documented one of the few cases of a positive coupling of activity in the larval and adult stages. Yet, contrary to larval activity, adult activity did not differ between core and edge populations. This indicates that the higher larval activity we documented is not shaped by a coupling with adult activity. Instead, our results are consistent with the hypothesis that a higher energy need in edge populations shaped the higher larval activity. Edge larvae showed a higher growth rate which is expected to evolve at the initial low population densities in newly founded edge populations. Moreover, higher growth rate showed the expected positive covariation with larval activity.

Increases in activity in the non‐dispersive stage in edge populations at an expansion front should be included in the ongoing debate whether evolutionary changes at invasion fronts are driven by adaptive versus non‐adaptive evolution. Moreover, they may have the potential to affect ecological interactions at expanding range fronts.
Anadromous sea lampreys (Petromyzon marinus) are ecosystem engineers in a spawning tributary
Authors: Hogg Robert S. , Coghlan Stephen M. , Zydlewski Joseph , Simon Kevin S.
Published: February 2014

Sea lampreys (Petromyzon marinus) disturb the substratum during nest construction and alter the physical habitat, potentially affecting other stream organisms. We quantified differences in depth, velocity, fine‐sediment coverage, embeddedness, intragravel permeability and benthic invertebrate assemblages (density and diversity) among nest mounds, nest pits and undisturbed reference locations over a 4‐month period after June spawning.

In 2010 and 2011, immediate and persistent effects of nest construction were assessed in summer (July) and in autumn (late September to early October), respectively. Randomly selected nests were sampled annually (25 each in summer and autumn).

Nest construction increased stream‐bed complexity by creating and juxtaposing shallow, swift, rocky habitat patches with deep, slow, sandy habitat patches. Mounds had a 50–143% less cover of fine sediment, and a 30–62% reduction in embeddedness, compared to pits and reference locations. These physical changes persisted into the autumn (almost 4 months).

Five insect families contributed 74% of the benthic invertebrate abundance: Chironomidae (27%), Hydropsychidae (26%), Heptageniidae (8%), Philopotamidae (7%) and Ephemerellidae (6%). Densities of Hydropsychidae, Philopotamidae and Heptageniidae were up to 10 times greater in mounds than in pits and adjacent reference habitat. In summer, mounds had twice the density of Chironomidae than did pits, and 1.5 times more than reference habitats, but densities were similar among the habitats in autumn.

These results suggest that spawning sea lampreys are ecosystem engineers. The physical disturbance caused by nest‐building activity was significant and persistent, increasing habitat heterogeneity and favouring pollution‐sensitive benthic invertebrates and, possibly, drift‐feeding fish.
Increased nitrogen leaching following soil freezing is due to decreased root uptake in a northern hardwood forest
Authors: Campbell John L. , Socci Anne M. , Templer Pamela H.
Published: February 2014

The depth and duration of snow pack is declining in the northeastern United States as a result of warming air temperatures. Since snow insulates soil, a decreased snow pack can increase the frequency of soil freezing, which has been shown to have important biogeochemical implications. One of the most notable effects of soil freezing is increased inorganic nitrogen losses from soil during the following growing season. Decreased nitrogen retention is thought to be due to reduced root uptake, but has not yet been measured directly. We conducted a 2‐year snow‐removal experiment at Hubbard Brook Experimental Forest in New Hampshire, USA to determine the effects of soil freezing on root uptake and leaching of inorganic nitrogen simultaneously. Snow removal significantly increased the depth of maximal soil frost by 37.2 and 39.5 cm in the first and second winters, respectively (P < 0.001 in 2008/2009 and 2009/2010). As a consequence of soil freezing, root uptake of ammonium declined significantly during the first and second growing seasons after snow removal (P = 0.023 for 2009 and P = 0.005 for 2010). These observed reductions in root nitrogen uptake coincided with significant increases in soil solution concentrations of ammonium in the Oa horizon (P = 0.001 for 2009 and 2010) and nitrate in the B horizon (P < 0.001 and P = 0.003 for 2009 and 2010, respectively). The excess flux of dissolved inorganic nitrogen from the Oa horizon that was attributable to soil freezing was 7.0 and 2.8 kg N ha−1 in 2009 and 2010, respectively. The excess flux of dissolved inorganic nitrogen from the B horizon was lower, amounting to 1.7 and 0.7 kg N ha−1 in 2009 and 2010, respectively. Results of this study provide direct evidence that soil freezing reduces root nitrogen uptake, demonstrating that the effects of winter climate change on root function has significant consequences for nitrogen retention and loss in forest ecosystems.
Texture analysis of cosmetic/pharmaceutical raw materials and formulations
Authors: Tai A. , Bianchini R. , Jachowicz J.
Published: February 2014

Synopsis

Objectives

The purpose of this work was to quantify textural properties of cosmetic and pharmaceutical raw materials.

Methods

Textural parameters such as hardness, consistency, cohesiveness, index of viscosity, stickiness and resilience were evaluated. The measurements were performed using texture analyser – a tensile metre equipped with special probes (in the form of acrylic cylinder and stainless steel sphere), which can penetrate the measured sample of a product recording the force, distance and time. The instrument simulates the action of a human finger touching the surface and probing the properties of an object. The set‐up has been previously shown to quantify the rheological/textural properties of cosmetic and pharmaceutical products such as creams, lotion and gels as well as rheological behaviour of human skin.

Results and Conclusions

The results include the analysis of water, glycerine and mineral oil as well as aqueous solutions of thickeners such as Acrylates/C10‐30 Alkyl Acrylate Crosspolymer (Ultrez‐20 obtained from Noveon) and carbomer. Solutions of common surfactants and complex surfactant formulations such as shampoos have also been investigated. The results, in the form plots of force as a function of time or distance, resulting from slow bidirectional probe movement (submergence and desubmergence) in the analysed fluid, were interpreted by considering buoyancy, drag and viscous drag force given by Stokes equation. The data can be used to correlate with tactile evaluations of products by trained panel evaluations.
Pathogenesis of percutaneous infection of goats with Burkholderia pseudomallei: clinical, pathologic, and immunological responses in chronic melioidosis
Authors: Soffler Carl , Bosco‐Lauth Angela M. , Aboellail Tawfik A. , Marolf Angela J. , Bowen Richard A.
Published: February 2014

Melioidosis is a severe suppurative to granulomatous infection caused by Burkholderia pseudomallei. The disease is endemic to South‐East Asia and Northern Australasia and is also of interest as a potential biological weapon. Natural infection can occur by percutaneous inoculation, inhalation or ingestion, but the relative importance of each route is unknown. Experimental infection models using mice have shown inhalation to be the most lethal route of exposure, but few studies have examined the pathogenesis of percutaneous infection despite its presumptive importance in natural disease. Caprine models are useful in the study of melioidosis because goats are susceptible to natural infection by B. pseudomallei, display similar epizootiology/epidemiology to that of humans within the endemic range and develop similar pathologic lesions. Percutaneous inoculation with 104 CFU of B. pseudomallei produced disease in all experimental animals with rapid dissemination to the lungs, spleen and kidneys. Initial fever was brief, but temperatures did not return to pre‐infection levels until day 18, concurrent with a dramatic lymphocytosis and the transition to chronic disease. Distribution and appearance of gross pathologic and radiographic lesions in goats were similar to caprine aerosol infection and to reported human disease. The similarities seen despite different routes of infection suggest that host or bacterial factors may be more important than the route of infection in disease pathogenesis. The nature of melioidosis in goats makes it amenable for modelling additional risk factors to produce acute clinical disease, which is important to the study of human melioidosis.
Nonformal education for improving educational outcomes for street children and street youth in developing countries: A systematic review
Authors: Shephard Daniel D.
Published: February 2014

Tens of millions of children and youth (up to 24 years of age) live and work on the streets of developing countries. Most of them are forced to leave formal education. As a potential solution, nonformal education (NFE) interventions have spread worldwide. However, no previous attempt has been made to address the state of evidence regarding effectiveness studies ofNFEfor street children and youth. This review addresses this gap by conducting the first systematic review concerning the effectiveness ofNFEfor improving educational outcomes for street children and street youth. The search was conducted in 35 structured electronic databases and numerous organizations and experts were also contacted. The screening of 9,271 titles resulted in the identification of zero prospective effectiveness studies with a counterfactual. Lessons are drawn from the highest quality excluded studies to inform future evaluations that seek to address this knowledge gap.

Key Practitioner Message: ●Practitioners should implement comparable intake and monitoring assessments to track changes consistently over time;●Programs informed by critical pedagogy and empowerment‐based approaches may improve behavioral outcomes;●Programs that work with street children and street youth should clarify how they identify their target population.
Novel combination therapy with imiquimod and sorafenib for renal cell carcinoma
Authors: Karashima Takashi , Komatsu Toshihiro , Niimura Mayumi , Kawada Chiaki , Kamada Masayuki , Inoue Keiji , Udaka Keiko , Kuroda Naoto , Shuin Taro
Published: February 2014

Objectives

To investigate whether the combination of the imidazoquinoline immune response modifier, imiquimod, and the multitargeted tyrosine‐kinase inhibitor, sorafenib, inhibits the growth of renal cell carcinoma in mice.

Methods

Female BALB/c mice were implanted subcutaneously with 2 × 105 RENCA mouse kidney cancer cells, and were treated with transcutaneously applied cream containing imiquimod and oral administrations of sorafenib beginning 5 days after implantation of the cells. Tumor incidence and burden were determined at 28 days after initiation of therapy. T cell infiltration in the tumor was determined by immunofluorescence staining with anti‐CD3‐ε and CD8‐α antibodies.

Results

Therapy with imiquimod, sorafenib or their combination was well tolerated. Combination therapy with imiquimod and sorafenib significantly inhibited tumor growth when compared with administration of control vehicle, imiquimod or sorafenib alone (P < 0.05). The CD3‐ and CD8‐positive T cells infiltrated into tumors to a greater degree in response to the combination therapy when compared with tumors treated with control vehicle or sorafenib alone.

Conclusions

Combination therapy with a tyrosine‐kinase inhibitor and an imidazoquinoline could be a promising therapeutic strategy for patients with renal cell carcinoma.
Tadalafil 5 mg once‐daily therapy for men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia: Results from a randomized, double‐blind, placebo‐controlled trial carried out in Japan and Korea
Authors: Takeda Masayuki , Yokoyama Osamu , Lee Sung Won , Murakami Masahiro , Morisaki Yoji , Viktrup Lars
Published: February 2014

Objectives

To gain further evidence on the efficacy, safety and tolerability of tadalafil 5 mg once‐daily in Asian men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.

Methods

Japanese and Korean men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia were randomized to once‐daily tadalafil 5 mg (n = 306) or placebo (n = 304) for 12 weeks.

Results

A significantly greater improvement (P < 0.001) in total International Prostate Symptom Score for the change from baseline (week 0) to study end‐point (week 12) was observed for tadalafil (−6.0) versus placebo (−4.5). Significantly greater improvements (P < 0.01) in total International Prostate Symptom Score for the change from baseline to weeks 4 and 8 were observed for tadalafil versus placebo. Significantly greater improvements (P < 0.05) in International Prostate Symptom Score voiding and storage subscores, and International Prostate Symptom Score Quality of Life Index were observed for the change from baseline to end‐point for tadalafil versus placebo. Significantly greater improvements (P < 0.001) in urinary symptoms were observed for tadalafil versus placebo for both Patient and Clinician Global Impressions of Improvement. No new safety concerns were identified.

Conclusions

These findings confirm the efficacy and safety profile of tadalafil 5 mg once‐daily in Asian men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia.
Bladder function of patients withParkinson's disease
Authors: Sakakibara Ryuji , Tateno Fuyuki , Nagao Takeki , Yamamoto Tatsuya , Uchiyama Tomoyuki , Yamanishi Tomonori , Yano Masashi , Kishi Masahiko , Tsuyusaki Yohei , Aiba Yosuke
Published: February 2014

Bladder function of patients withParkinson's disease alters significantly: the majority of patients have overactive bladder (urinary urgency/frequency) with little or no post‐void residuals. This seems to be the result of an altered brain–bladder relationship, as inParkinson's disease, the frontal‐basal gangliaD1dopaminergic circuit that normally suppresses the micturition reflex is altered. The pathophysiology of the bladder dysfunction inParkinson's disease differs from that in multiple system atrophy; therefore, it might also aid in differential diagnosis. The effects of levodopa, the major drug to treat motor dysfunction, on the bladder inParkinson's disease vary significantly; therefore, add‐on therapy is often required. Anticholinergic drugs are the first‐line treatment, with particular care for cognitive function in elderly patients. The second‐line treatment includes serotonergics drug, desmopressin and others. Newer modalities include deep brain stimulation that improves the bladder inParkinson's disease; and botulinum toxin is promising, particularly in difficult cases. These treatments might be beneficial in maximizing the patients' quality of life.
Light‐Dependent Chloroplast Reorientation in Mougeotia and Mesotaenium: Riased by Pigment‐Regulated Plasmalemma Anchorage Sites to Actin Filaments?
Authors: Grolig F. , Wagner G.
Published: February 2014

Conjugatophycean green algae, such as Mougeotia and Mesotaenium, are presumably the most ancient organisms to show phytochrome‐mediated photomodulatory processes, i.e. chloroplast reorientational movements. Experiments have provided striking evidence for a dichroic mode of light absorption by the phytochrome molecules located at the periphery of the cylindrical cell; in addition, the transition moment of the chromophoric group of phytochrome has been shown to change by a fixed angle upon conversion of Pr to Pfr and vice versa. Consequently, a hypothesis has been put forward involving a tetrapolar phytochrome gradient at the plasmalemma. This presumed pigment pattern precisely controls chloroplast reorientation in the low‐irradiance response. Intriguingly, a blue‐light absorbing pigment is expressed in Mougeotia as well, which also mediates low‐irradiance response via a presumed tetrapolar gradient, apparently independent of the phytochrome.

Two hypotheses for the controlling mechanism of chloroplast reorientation have been put forward:

Coupling of the influx of calcium through the plasmalemma to the tetrapolar gradient of the sensor pigment proper, resulting in a tetrapolar gradient of calcium in the cytoplasm. This is the “reorientation via calcium” hypothesis.

Coupling of actin anchorage sites on the plasmalemma to the tetrapolar gradient of the sensor pigment proper, resulting in a tetrapolar gradient of actin anchorage sites. Cytoplasmic calcium, released from internal stores or taken up through the plasmalemma, triggers actomyosin interaction. This is the “reorientation via anchorage sites” hypothesis.

Consistent with the latter hypothesis, photoregulation by two steps seems to be indicated, (i) cytoplasmic initiation of actomyosin interaction, (ii) the graded formation of plasmalemma anchorage sites for actin filaments.
General Mechanisms for Solute Transport Across the Tonoplast of Plant Vacuoles: a Patch‐Clamp Survey of Ion Channels and Proton Pumps
Authors: Hedrich R. , Barbier‐Brygoo H. , Felle H. , Flügge U. I. , Lüttge U. , Maathuis F. J. M. , Marx S. , Prins H. B. A. , Raschke K. , Schnabl H. , Schroeder J. I. , Struve I. , Taiz L. , Ziegler P.
Published: February 2014

The electrical properties of the tonoplast from a large variety of plant materials such as mesophyll cells, storage cells, tumor cells, suspension cultured cells, guard cells, coleoptile cells, and liverwort cells have been investigated using the patch‐clamp technique. Whole‐vacuole recordings were employed to study the dynamics of an ATP‐dependent proton pump by directly measuring the electrogenic currents. The addition of Mg‐ATP induced an inwardly directed current which depolarized the tonoplast (the vacuole becoming positive inside). Furthermore, voltage‐dependent passive ion fluxes were analyzed using whole vacuoles and isolated membrane patches. Whole‐vacuolar currents and single‐channel currents were induced at hyperpolarizing potentials, whereas currents decreased at positive trans‐tonoplast potentials. The electrical properties of the tonoplast of vacuoles from various plant tissues were similar and it was concluded that ion fluxes across the tonoplast follow the same general mechanisms.
Diurnal Changes in the Regulatory Properties of Phosphoenolpyruvate Carboxylase in CAM Plants: Are Alterations in the Quaternary Structure Involved?
Authors: Krüger I. , Kluge M.
Published: February 2014

Day — and night‐forms of phosphoenolpyruvate carboxylase (EC 4.1.1.31) (PEP‐C) were extracted from leaves of the CAM plantKalanchoë daigremontiana. During storage after extraction, the day‐form spontaneously lost its sensitivity towards the allosteric inhibitorl‐malate. This effect was accelerated by inorganic phosphate, PEP, 3‐PGA and G‐6‐P.l‐Malate however stabilized the malate sensitivity of the day‐form of PEP‐C.

Crude desalted extracts of the day‐form and of the night‐form of PEP‐C were subjected to ultracentrifugation on a continuous sucrose gradient in the presence of malate and of marker enzymes. Both forms of PEP‐C were found to have relative molecular masses of about 200,000. This suggests that both forms represent the dimers of the enzyme protein. The result also suggests that reversible dissociation and association of enzyme subunits is not the mechanism which brings about the interconversion of the two PEP‐C forms during the diurnal CAM cyclein vivo.
Superoxide Dismutase and Unribosylated Cytokinins Interact in the Control of NAD(P)H‐Peroxidation
Authors: Elstner E. F. , Galek Helena
Published: February 2014

NAD(P)H is rapidly oxidized in the presence of peroxidase, a substituted monophenol such as p‐coumaric acid, and Mn2+ ions. As recently reported by Miller (1985), this NAD(P)H oxidation at the expense of molecular oxygen is inhibited by submicromolar concentrations of Cu2+ ions. This inhibition by cupric ions is counteracted by micromolar concentrations of cytokinins. We now show that NAD(P)H‐oxidation by the above system is under the control of superoxide dismutase, where in the absence of cytokinin‐copper, superoxide dismutase stimulates NAD(P)H‐oxidation. In the presence of unribosylated cytokinins and copper, however, superoxide dismutase acts as an inhibitor. Thus cytokinins and superoxide dismutase may interact in the control of the redox state of plant cells.
Biochemical and Immunological Properties of Solubilized Tonoplast ATPase of the Facultative CAM Plant Mesembryanthemum crystallinum in the C3 and CAM States
Authors: Struve I. , Lüttge U.
Published: February 2014

A nitrate‐sensitive, azide‐insensitive ATPase isolated from M. crystallinum in the C3 and in the CAM state has been solubilized in active form using octylglucoside and Zwittergent 3–14. Like the membrane‐bound tonoplast ATPase, the solubilized ATPase showed an increase in ATP‐hydrolysis activity after transition from the C3 to the CAM mode of photosynthesis. The characteristics of the membrane‐bound and the solubilized tonoplast ATPase were comparable with respect to salt stimulation, inhibitor effects, and MgATP2–‐concentration dependence. Differing from the membrane‐bound ATPases, the solubilized ATPase from C3‐ and CAM‐M. crystallinum showed a pH optimum between pH 6.5 and 7.0.

In order to compare the solubilized ATPases immunologically, antibodies were prepared against the tonoplast fraction of C3‐ and CAM‐M. crystallinum. A cross‐reaction was observed between antibodies against the tonoplast ATPase from C3‐ and CAM‐M. crystallinum and the solubilized ATPase from C3‐ and CAM‐M. crystallinum. A cross‐reaction was also observed between antibodies against the tonoplast ATPase from C3‐ and CAM‐M. crystallinum and the solubilized tonoplast ATPase from Kalanchoë daigremontiana. However, there was no cross‐reaction with the solubilized plasmalemma ATPase from Festuca rubra.
Isolation and Characterization of Mustard (Sinapis alba L.) Seed Storage Proteins
Authors: Fischer W. , Schopfer P.
Published: February 2014

A total storage protein fraction was prepared from mustard (Sinapis alba L.) seeds via isolated protein bodies and characterized by sedimentation, immunological, and electrophoretic techniques. Mustard seed storage protein consists of three fractions (1) a “legumin‐like” 13‐S complex composed of two pairs of disulfide‐linked polypeptides (16.5 + 28.5 kDa and 19.5 + 34 kDa, respectively) and two single polypeptides (18 kDa and 26 kDa), (2) a “vicilin‐like” 9‐S complex composed of two glycoproteins (64 kDa and 77 kDa), and (3) two small polypeptides (10 kDa and 11 kDa) which probably represent the 1.7‐S complex found in other Cruciferae. In contrast to related species, no glycosylated polypeptide was found in the 13‐S complex. Immunological relationships were found between the paired polypeptides of the 13‐S complex but not between polypeptides of the 13‐S complex and polypeptides of the 9‐S complex. Pulse‐chase labeling and in vitro translation of polysomal RNA from young embryos demonstrated that the polypeptides of the 13‐S complex originate from high molecular mass precursors, except for the 18 kDa polypeptide which appears to be synthesized in its final size. The amino‐acid composition of the major polypeptides of the mustard storage protein is given.
Phototropism in Higher Plants — Controversies and Caveats1
Authors: Briggs W. R. , Baskin T. I.
Published: February 2014

Recent literature on light‐induced changes in the distribution of growth and of endogenous growth regulators in the development of phototropic curvature is reviewed. It is concluded that in a great many cases the Cholodny‐Went hypothesis is sufficient to account for the growth changes bringing about curvature, though in certain dicotyledonous seedlings differential effects of light on the synthesis of growth inhibitors across the tissue from the lighted to the shaded side are implicated. The problems in the interpretation of results from experiments in which more than one photoresponse may be simultaneously induced are discussed and methods of circumventing them considered. Action spectroscopy suggests that dicotyledonous seedlings may have the same phototropic photoreceptor as monocotyledonous seedlings.
One Hundred and One Years of Chemotaxis. Pfeffer, Pheromones, and Fertilization
Authors: Jaenicke L.
Published: February 2014

Chemotaxis of flagellated unicellular gametes was discovered by Wilhelm Pfeffer. In most known systems the lure is a metabolic waste product ritualized for sexual attraction. A special case are the female gametes of brown algae. They secrete polyunsaturated C‐8 or C‐11 hydrocarbons mostly with straight chain or unsubstituted tri‐, penta‐ or heptacyclic structures. Their biogenetic origin stems from polyunsaturated fatty acids. The reactions leading to the different structures comprise lipoxygenase‐type radical formations and dehydrogenating decarboxylations. — Most gametes produce a variety of such hydrocarbons; however, only one of them is the active principle. Biological activity is highly stereospecific; but frequently the bouquets contain lures for other species. Although cross‐fertilization is excluded, they may be used to defend the habitat against overgrowth by other seaweeds. Besides chemoattractive action, some secretions also synchronize hatching of the spermatozoids. One of the compounds responsible is characterized by an epoxy substitution. — For most of the structures, stereospecific and versatile syntheses are available, which were used to investigate the binding site. This forms a template for the signal molecule with specifically situated polarizing groups that interact with the π‐electrons of the double bonds. The message is transformed into changes of flagellar beat patterns which ensure meeting of the partners followed by fertilization.
Salt‐Induced Hypodermal Transfer Cells in Roots of Prosopis farcta and Ion Distribution within Young Plants
Authors: Winter E.
Published: February 2014

Prosopis farcta was grown on hydroculture with additions of 0.5, 10, 50, and 100 mM NaCl and without salt treatment. In plants from a 0.5 mM NaCl treatment, Cl− was taken up into stems and leaves, but Na+ was withheld from the shoot. At 10 mM NaCl, shoot K+ concentration was below that of the control; Na+ and Cl− were taken up to stems and cotyledons in nearly equimolar amounts. However, in the leaves, Na+ concentrations were only half of those of Cl−. With increasing salt stress, Na+ and Cl− were transported to the shoot, but kept at relatively low levels in the roots. Na+/ K+ ratios in roots did not increase proportionally to those in the solution. At an external Na+/K+ of > 5 and a root Na+/K+ of >1 (10 mM NaCl treatment), K+ selectivity was induced which rose exponentially with increasing salt stress; and cell wall protuberances were discovered in the hypodermis at the zone of side root formation. These transfer cells were found neither in roots from the 0.5 mM NaCl treatment nor in the controls. Their possible role in the Na+/K+ selectivity of the roots of Prosopis farcta is discussed.
Cell Biology and Algal Taxonomy and Evolution Absolute Orientations of Basal Bodies in Green Algae Evaluated by Light Microscopy
Authors: Reize I. B. , Melkonian M.
Published: February 2014

Using high magnification Nomarski interference microscopy a series of optical sections has been obtained through flagellated cells of several green algae in an attempt to establish the absolute orientation of their basal bodies. Using this technique we have confirmed that inSpermatozopsis similisbasal bodies are displaced into the 1/7 o'clock position, whereas in gametes ofEnteromorpha linza, and zoospores ofTrebouxia ericibasal bodies are displaced into the 11/5 o'clock position. In addition we report for the first time that in zoospores ofMicrothamnion kuetzingianumbasal bodies are also displaced into the 11/5 o'clock position. Basal body absolute orientations can thus be determined by light microscopy and do not require serial section electron microscopy. The method should be useful for class‐level recognition of unknown green algae at the light microscope level.
Cryptophycean‐Like Double Membrane‐Bound Chloroplast in the Dinoflagellate, Dinophysis Ehrenb.: Evolutionary, Phylogenetic and Toxicological Implications
Authors: Schnepf E. , Elbrächter M.
Published: February 2014

Dinoflagellates of the genus Dinophysis are responsible for diarrhetic shellfish poisoning. Phototrophic species have an orange primary fluorescence indicating the presence of phycobilins. The chloroplasts greatly resemble cryptophycean chloroplasts having pairs of thylakoids and electron‐dense material in the thylakoid lumen. They are bound by only two membranes, in contrast to the blue‐green chloroplasts of Amphidinium wigrense Woloszynsk, which are enveloped by three membranes (Wilcox and Wedemayer, 1985). Possible ways of evolution of the Dinophysis chloroplasts, phylogenetical questions and implications for the monitoring of toxic dinoflagellates are discussed.
Quantification by ELISA of Cytokinins in Root‐Pressure Exudates of Urtica dioica Plants Grown under Different Nitrogen Levels
Authors: Fußeder A. , Wagner B. , Beck E.
Published: February 2014

ELISAs for [9R]iP, [9R]Z and (diH) [9R]Z have been worked out which, in combination with HPLC., allow the quantitative determination of cytokinins of the isopentenyladenin‐, zeatin‐ and dihydrozeatin‐type in samples of plant material. The three ELISAs are optimally applicable in the range from 0.5 to 20 pmoles of cytokinins per assay but reliable measurements can still be performed down to 0.05 pmoles. The assay has been applied to root pressure exudates obtained from Urtica dioica plants grown under controlled conditions and at different nitrogen (nitrate) levels. The predominant cytokinins of the xylem exudate were Z, Z‐nucleotide, iP, [9R]iP and iP‐nucleotide, while (diH)Z was present to a minor extent. The concentrations of these compounds were found to range between 0.2 and 3 pmoles per ml exudate.

Interestingly, no effect of the different nitrogen nutrition on the pattern and concentration of cytokinins in the xylem exudate could be established.
Helicteres ovata (Sterculiaceae), Pollinated by Bats in Southeastern Brazil
Authors: Sazima M.
Published: February 2014

The interactions between Helicteres ovata flowers and the bat Glossophaga soricina were observed in south eastern Brazil. During bat visits, pollen is unselectively spread over small areas of the visitors' body (which is uncommon for a bat flower). Seemingly related to this limitation of pollen availability, the variable orientation of the stigma makes it able to pick up grains scattered on almost any part of the bat's body. Day visitors were two hummingbird species which do not pollinate the flowers. Most Brazilian Helicteres species have red flowers with a long androgynophore. The few modifications departing from the bird flower type within the genus suggest, together with the problem of pollen placing and collecting, that H. ovata is a recent derivate from the ornithophilous stock.
Analysis of cDNA Clones Encoding the Entire Ferredoxin I Precursor Polypeptide from Spinach
Authors: Wedel N. , Bartling D. , Herrmann R. G.
Published: February 2014

We report the isolation and characterization of a recombinant cDNA phage from a lambda gt11 expression library made from polyadenylated spinach RNA that encodes the entire precursor polypeptide of ferredoxin I. The deduced sequence predicts a molecular mass of 10.5 kDa (97 amino acid residues) for the mature protein and a transit peptide of 50 residues (5.2 kDa). In vitro synthesized ferredoxin precursor was used for import experiments with isolated unbroken spinach chloroplasts. The polypeptide was correctly directed to the organelle stroma and processed to the size of the mature protein. Northern analysis indicates a mRNA size of ca. 850 nucleotides which is close to the size of the cDNA insert (ca. 700 bp).
Quantum Requirement for Photoreactivation of Inactivated Nitrate Reductase of Neurospora crassa Strain al‐2, bd
Authors: Pottiez B. , Krippahl G. , Ninnemann H.
Published: February 2014

Chemically inactivated nitrate reductase of Neurospora crassa strain al‐2, bd can be photoreactivated by blue light. The quantum requirement for this reaction in the presence of exogenous FMN was determined with different light intensities. The results are discussed with the alternate assumptions that free FMN or photoactivated FAD bound to the nitrate reductase molecule is the reactivating species.
The Molecular Analysis of the Light Adaptation Reactions in the Yellow‐green AlgaPleurochloris meiringensis(Xanthophyceae)
Authors: Büchel C. , Wilhelm C. , Lenartz‐Weiler I.
Published: February 2014

The xanthophycean algaPleurochloris meiringensiswas homocontinuously cultured under high light (16 W/m2) and low light (2 W/m2) conditions. In low light cells, the chlorophyll a content and the dry weight on per cell basis is increased, the maximal photosynthetic capacity per chlorophyll is decreased. The content of chlorophyll c, vaucheriaxanthin‐ester and heteroxanthin is similar in both cultures, whereas the content of diadinoxanthin and ß‐carotene is twice as high in high light cultures. High light cells contain more photosystem I and cytochrome f per chlorophyll than low light cells, whereas the QBcontent is found to be unchanged. Therefore, the ratio reaction center II/reaction center I is twofold higher in low light cells than in high light ones. The regulation of energy distribution between the photosystems is examined by fluorescence emission spectra at 77 K scanned after different preillumination of the cells. No wavelength dependent state I/state II transition can be detected. However,P. meiringensisregulates the energy distribution in response to light intensity: The higher the irradiance of preillumination, the higher the energy transfer to photosystem I. The sensitivity of the regulation to light intensity is increased in low light cells.
Photosensory Adaptation in Plants
Authors: Galland Paul
Published: February 2014

Photosensory adaptation (range adjustment) is of great importance in plants (including fungi and various microorganisms) that operate in large intensity ranges. The adaptation mechanisms of plants have some features in common with those of vertebrates and invertebrates. As with those systems, plants have biphasic exponential dark‐adaptation kinetics, that are much slower than the corresponding light adaptation kinetics. One needs to distinguish between sensor adaptation, which regulates range adjustment, and effector adaptation (habituation), which regulates the motor apparatus of the organism (flagellar movement or cell wall growth). In Phycomyces, and perhaps Stentor, sensor adaptation is mediated by the photoreceptor system. In contrast to vertebrates and invertebrates, dark adaptation can be controlled in some plants by special photoreceptors. In Phycomyces, these can be either photo‐products of the actinic photoreceptor(s) or not yet identified receptor pigments. In higher plants phytochrome can alter the state of adaptation.
Sugar Transport and Sulfite Action in Etioprotoplasts, Semi‐Etioprotoplasts and Green Protoplasts of Avena sativa L.
Authors: Lorenc‐Plucińska Gabriela , Miszalski Z. , Ziegler H.
Published: February 2014

The mechanism of glucose and sucrose transport and the influence of various concentrations of sulfite on its activity was studied in mesophyll protoplasts (etioprotoplasts, semi‐etioprotoplasts and green protoplasts) isolated from oat (Avena sativa L.) seedlings.

Kinetic analysis of [14C] glucose loading (in darkness) revealed in each kind of protoplasts the presence of two transport components. At low exogenous glucose concentrations a saturable system was the main mode of transport. At concentrations higher than 20 mM the loading of glucose in all types of protoplasts was dominated by a non‐saturable, linear diffusion‐like component. The rate of glucose uptake was greatest in etioprotoplasts and lowest in green protoplasts.

In contrast to the above we have not found saturable components of sucrose transport in any kind of protoplasts. The rate of its uptake was greatest in semi‐etioprotoplasts.

Sulfite, at a concentration of < 1.0 mM stimulated and at ≥ 1.0 mM inhibited the uptake of glucose to etioprotoplasts and semi‐etioprotoplasts and inhibited that to green protoplasts at any concentration. The transport of sucrose underwent a significant inhibition in the various types of protoplasts only under the influence of 10.0 mM of sulfite ions.

Inhibition of glucose uptake by sulfite was of the non‐competitive type.

Sulfite also affected the level of adenylic nucleotides and lowered the energy charge and ATP/ADP ratio.

Intensity of sulfite uptake was significantly higher in green protoplasts than in etioprotoplasts.
The Regulation of Chlorophyll Biosynthesis by the Action of Protochlorophyllide on glut‐RNA‐Ligase
Authors: Dörnem D. , Kotzaba K. , Rich P. , Breu V. , Senger H.
Published: February 2014

The pigment mutant C‐2A' of the green alga Scenedesmus obliquus accumulates considerable amounts of protochlorophyllide (PChlide), when grown in darkness. In this paper it is demonstrated that the accumulated PChlide directly acts on glut‐RNA‐ligase and thereby blocks further biosynthesis of ALA and chlorophyll. By increasing the amount of ligase at constant concentrations of PChlide and glut‐RNA it could clearly be demonstrated that PChlide directly inhibits ligase activity and does not act on the t‐RNA. The inhibitory effect of other tetrapyrroles like chlorophyll a, pheophytin a and protoporphyrin IX was much less effective even at oversaturating concentrations.
Peroxisomes in Rice Coleoptiles Grown in Air and in Anoxia
Authors: De Bellis L. , Rascio N. , Pistelli L. , Alpi A.
Published: February 2014

Rice coleoptiles grow under anoxia. When the ultrastructure of anoxic coleoptile cells was examined, it was seen that most organelles maintain their integrity, with the exception of peroxisomes (unspecialized type). The lack of O2 greatly reduced the number of these organelles and altered the ultrastructure of the remaining ones. To examine the effect of O2 on peroxisome development in more detail, coleoptiles grown in air were transferred to N2 and anoxic coleoptiles were transferred to oxygen. Marker enzyme activity was measured in entire coleoptiles as well as in the isolated organelles. As expected, anoxia greatly depressed enzyme activity when imposed from the beginning of the germination process, while it had a lesser effect when imposed for only two days on aerobic seedlings. When coleoptiles were grown constantly under N2, the density of the organelles was 1.216 g/cm3, while the corresponding aerobic organelles showed a buoyant density of 1.241 g/cm3. When transferred to air the anoxic peroxisomes reached the intermediate density of 1.227 g/cm3. The results confirm the particular sensitivity of rice peroxisomes to O2 availability.
Intraspecific Variation in the Amino Acid Content of Floral Nectar
Authors: Gottsberger G. , Arnold T. , Linskens H. F.
Published: February 2014

In order to evaluate the constancy of amino acid composition and concentration, several randomly collected samples of genuine floral nectar from different flowers of several plant species were analysed. Although there seems to exist a rough pattern of species‐specific nectar amino acid composition, amino acid concentration varied strongly from sample to sample. Apart from the lack of constancy in concentration of floral amino acids, our samples do not show amino acid concentration values as assigned typical for the pertinent pollination mode by other workers.
A New Way to Investigate Living Flagellated/Ciliated Cells in the Light Microscope: Immobilization of Cells in Agarose
Authors: Reize Ingo Botho , Melkonian Michael
Published: February 2014

A method for cell immobilization of living flagellated/ciliated cells in agarose has been developed that allows single cells to be viewed for prolonged periods of time using high resolution light microscopy. Embedding in ultralow gelling, soft agarose preserves cellular functions of various flagellated/ciliated protists including delicate species, marine dinoflagellates, cryptomonads, contractile ciliates, etc. for days. Cell division, morphogenesis of cell organelles and intracellular movements can thus be studied for the first time in great detail. The method may also be useful for the isolation of flagellated/ciliated protists from nature and for the establishment of axenic clonal cultures in a single step.
Evidence for the Presence of Chlorophyllide b in the Green Alga Scenedesmus obliquus in vivo
Authors: Kotzabasis Kiriakos , Senger Horst
Published: February 2014

Chlorophyllide b could be extracted from the wild type of Scenedesmus obliquus and its pigment mutant C‐2A'. Its identity was proved by absorption and fluorescence spectroscopy and by a positive hydroxylamine test. Chlorophyllide b could be transformed into pheophorbide b and methylpheophorbide b. The formation of chlorophyllide b from chlorophyll b by dephytylation with chlorophyllase could be ruled out. The stimulation of chlorophyllide b biosynthesis with o‐phenanthroline, as described in the literature, could not be confirmed under physiological conditions.