bluuebunny/crossref_metadata_2025 huggingface dataset:
Crevicular fluid endothelin‐1 levels in periodontal health and disease
Authors: Pradeep A. R. , Guruprasad C. N. , Swati P. , Shikha C.
Published: October 2007

Background and Objective:  Endothelin‐1 is a 21‐amino‐acid peptide with multifunctional regulation. Initial research indicated that endothelin‐1 levels in the gingival crevicular fluid from patients with chronic periodontitis were higher than those in the gingival crevicular fluid from healthy subjects. The aim of the present study was to assess the relationship between the clinical parameters and the concentrations of endothelin‐1 within the gingival crevicular fluid from inflamed gingiva and periodontitis sites and, subsequently, after the treatment of periodontitis sites.

Material and Methods:  A total of 60 subjects were divided into three groups – healthy (group I), gingivitis (group II) and chronic periodontitis (group III) – based on gingival index, pocket probing depth and clinical attachment loss. A fourth group consisted of 20 subjects from group III, 6–8 wk after treatment (i.e. scaling and root planing). Gingival crevicular fluid samples collected from each patient were quantified for endothelin‐1 using an enzymatic immunometric assay.

Results:  Endothelin‐1 was not detected in any sample from any of the study groups.

Conclusion:  The results showed that all the gingival crevicular fluid samples were negative for the endothelin‐1 molecule. Therefore, endothelin‐1 cannot be considered as a potential biomarker of periodontal disease progression.
Keeping track of time under ice and snow in a sub‐arctic lake: plasma melatonin rhythms in Arctic charr overwintering under natural conditions
Authors: Strand Jo Espen Tau , Aarseth Jo Jorem , Hanebrekke Tanja Lexau , Jørgensen Even Hjalmar
Published: October 2007

Abstract:  Although photoperiod is considered as a major environmental cue for timing of seasonal events in fish, little is known about the photic information perceived by fish in different aquatic environments. The strongly seasonal Arctic charr, Salvelinus alpinus, reside in lakes covered by thick ice and snow throughout the dark winter in the north. In the present study, we have measured diel changes in their plasma melatonin concentrations from September to June in Lake Storvatnet (70°N), northern Norway. In addition, we have measured the in vitro melatonin production of Arctic charr pineal glands held at experimental light conditions. From September to April a diel profile in plasma melatonin was seen in the charr in Lake Storvatn, with highest concentrations at night. This profile reflected the prevailing above‐surface photoperiod, even in February when there were minimal changes in sub‐surface irradiance between day and night. In June, plasma melatonin was low throughout the 24‐hr cycle, despite there being a marked sub‐surface difference in irradiance between night and day. At this time the irradiance in night probably remained above the threshold for suppression of melatonin production. The in vitro experiments revealed no endogenous rhythm in the pineal melatonin secretion, supporting the conclusion that the diel profile seen in the Arctic charr in their natural habitat was driven by ambient photoperiod. In conclusion, the Arctic charr appear to keep track of time even under the extreme conditions of high latitudes during winter, when lakes have thick ice and snow cover.
A randomized, placebo‐controlled trial of controlled release melatonin treatment of delayed sleep phase syndrome and impaired sleep maintenance in children with neurodevelopmental disabilities
Authors: Wasdell Michael B. , Jan James E. , Bomben Melissa M. , Freeman Roger D. , Rietveld Wop J. , Tai Joseph , Hamilton Donald , Weiss Margaret D.
Published: October 2007

Abstract:  The purpose of this study was to determine the efficacy of controlled‐release (CR) melatonin in the treatment of delayed sleep phase syndrome and impaired sleep maintenance of children with neurodevelopmental disabilities including autistic spectrum disorders. A randomized double‐blind, placebo‐controlled crossover trial of CR melatonin (5 mg) followed by a 3‐month open‐label study was conducted during which the dose was gradually increased until the therapy showed optimal beneficial effects. Sleep characteristics were measured by caregiver who completed somnologs and wrist actigraphs. Clinician rating of severity of the sleep disorder and improvement from baseline, along with caregiver ratings of global functioning and family stress were also obtained. Fifty‐one children (age range 2–18 years) who did not respond to sleep hygiene intervention were enrolled. Fifty patients completed the crossover trial and 47 completed the open‐label phase. Recordings of total night‐time sleep and sleep latency showed significant improvement of approximately 30 min. Similarly, significant improvement was observed in clinician and parent ratings. There was additional improvement in the open‐label somnolog measures of sleep efficiency and the longest sleep episode in the open‐label phase. Overall, the therapy improved the sleep of 47 children and was effective in reducing family stress. Children with neurodevelopmental disabilities, who had treatment resistant chronic delayed sleep phase syndrome and impaired sleep maintenance, showed improvement in melatonin therapy.
Non‐invasive monitoring of oxidative skin stress by ultraweak photon emission (UPE)‐measurement. I: mechanisms of UPE of biological materials
Authors: Khabiri Faryar , Hagens Ralf , Smuda Christoph , Soltau Andreas , Schreiner Volker , Wenck Horst , Wittern Klaus‐Peter , Duchstein Hans‐Jürgen , Mei Weiping
Published: October 2007

Background/purpose: Oxidation of proteins and amino acids is associated with generation of ultraweak photon emission (UPE), which may be used to assess oxidative processes in the skin in a non‐invasive way. This first part of a series of reports addresses the physicochemical basis of oxidation‐induced UPE in the skin, with a special focus on the contribution of amino acid oxidation.

Methods: UPE of biological samples and protein/amino acid solutions following oxidation with H2O2 in the presence of Fe2+ was recorded using a sensitive photomultiplier system. Signals were analyzed with regard to overall signal intensity and spectral distribution.

Results: Increasing concentrations of H2O2 in aqueous bovine serum albumin solutions induced linearly correlated UPE and protein carbonyl compounds, with a substantially higher sensitivity for the measurement of UPE. In single amino acid solutions, strong UPE signals were generated by oxidation from Phe, Trp, His, and Cys, and weak signals from Lys and Thr. Analysis of reaction products by MS revealed high oxidative material turnover for Cys and His, whereas barely detectable oxidative material turnover seems to be sufficient to generate a UPE signal of similar strength from Trp and Phe. Combination of different amino acids did not result in a simple addition of individual oxidation‐induced UPE signals, but in interactions ranging from antagonism to clear synergism. Synergism was evident between Trp‐ and UPE‐generating amino acids such as Thr, Cys, and His, with the strongest synergism by far observed between Trp and His. The strikingly different individual UPE spectra of His and Trp, despite being of comparable overall strength, were congruent with a pure Trp UPE spectrum after combining His with Trp in solution, indicating energy transfer between both amino acids. Combination of Trp and DNA, which also gives UPE signals following oxidation, did not result in a synergistically enhanced or antagonized overall UPE signal, but in a simple addition of individual UPE signals.

Conclusion: Measurement of UPE could be proven to be a highly sensitive method to assess oxidative processes in biological molecules. The reported data indicate that UPE generated by oxidation stressed skin is mainly due to non‐fluorescent photon emission via Trp, whereby Trp acts as an energy receptor from other excited species of oxidation‐modified amino acids.
Protein Transport Across the Parasitophorous Vacuole ofPlasmodium falciparum: Into the Great Wide Open
Authors: Charpian Stefan , Przyborski Jude M.
Published: October 2007

The human malaria parasitePlasmodium falciparumresides and multiplies within a membrane‐bound vacuole in the cytosol of its host cell, the mature human erythrocyte. To enable the parasite to complete its intraerythrocytic life cycle, a large number of parasite proteins are synthesized and transported from the parasite to the infected cell. To gain access to the erythrocyte, parasite proteins must first cross the membrane of the parasitophorous vacuole (PVM), a process that is not well understood at the mechanistic level. Here, we review past and current literature on this topic, and make tentative predictions about the nature of the transport machinery required for transport of proteins across the PVM, and the molecular factors involved.
Keratinocyte Growth Factor Receptor Ligands Target the Receptor to Different Intracellular Pathways
Authors: Belleudi Francesca , Leone Laura , Nobili Valerio , Raffa Salvatore , Francescangeli Federica , Maggio Maddalena , Morrone Stefania , Marchese Cinzia , Torrisi Maria Rosaria
Published: October 2007

The keratinocyte growth factor receptor (KGFR)/fibroblast growth factor receptor 2b is activated by high‐affinity‐specific interaction with two different ligands, keratinocyte growth factor (KGF)/fibroblast growth factor (FGF)7 and FGF10/KGF2, which are characterized by an opposite requirement of heparan sulfate proteoglycans and heparin for binding to the receptor. We investigated here the possible different endocytic trafficking of KGFR, induced by the two ligands. Immunofluorescence and immunoelectron microscopy analysis showed that KGFR internalization triggered by either KGF or FGF10 occurs through clathrin‐coated pits. Immunofluorescence confocal microscopy using endocytic markers as well as tumor susceptibility gene 101 (TSG101) silencing demonstrated that KGF drives KGFR to the degradative pathway, while FGF10 targets the receptor to the recycling endosomes. Biochemical analysis showed that KGFR is ubiquitinated and degraded after KGF treatment but not after FGF10 treatment, and that the alternative fate of KGFR might depend on the different ability of the receptor to phosphorylate the fibroblast growth factor receptor substrate 2 (FRS2) substrate and to recruit the ubiquitin ligase c‐Cbl. The recycling endocytic pathway followed by KGFR upon FGF10 stimulation correlates with the higher mitogenic activity exerted by this ligand on epithelial cells compared with KGF, suggesting that the two ligands may play different functional roles through the regulation of the receptor endocytic transport.
Intrusive luxation of primary teeth
Authors: Moura Lúcia de Fátima Almeida de Deus , Bezerra Ana Cristina Barreto , Amorim Lílian de Fátima de Guedes , Moura Marina de Deus , Toledo Orlando de Ayrton
Published: October 2007

Abstract –  Traumatic injuries caused by intrusion account for 4–22% of the damage in anterior primary teeth and are generally related to axial impact. They are more frequent in children aged 1–3 years because of the additional high resilience and flexibility of the primary teeth supporting structures. The treatment decision will depend on the magnitude of the trauma and on the displacement position. In most cases, radicular displacement occurs towards the labial bone plate. The clinical decision of spontaneous re‐eruption and observation were adopted. This study aims at presenting a literature review illustrated with two case reports of patients having intrusive luxation injuries of the primary incisors.
School teachers’ knowledge of tooth avulsion and dental first aid before and after receiving information about avulsed teeth and replantation
Authors: Al‐Asfour Adel , Andersson Lars , Al‐Jame Quomasha
Published: October 2007

Abstract –  School teachers can play an important role in improving the prognosis of avulsed permanent teeth of school children after they are informed about the immediate and proper dental first aid steps to be taken at the time of an accident. The aims of this study were: (i) to assess the knowledge level of emergency measures for tooth avulsion in Kuwaiti intermediate school teachers and (ii) to determine if a short lecture about tooth avulsion and replantation could improve teachers’ knowledge on this topic. Eighty‐five teachers at two intermediate schools (children 10–14 years old) in Kuwait were interviewed using a questionnaire about their first‐aid knowledge with particular focus on the following five categories: General knowledge of teeth and avulsion, replantation of primary and permanent teeth, how to clean an avulsed tooth before replantation, extra‐oral time and storage methods and media for an avulsed tooth. For each category, a score ranging from 0–3 was possible. An informative 30‐min lecture about tooth avulsion and replantation was presented to a group of 43 teachers. After the lecture, the knowledge level of the teachers was re‐tested using the same method. Descriptive statistics was used to describe and analyze the data. Improvement in teacher knowledge to an adequate (score of 2) or complete (score of 3) level was observed after the lecture in all five categories. The general knowledge of tooth avulsion and replantation improved from 39% to 97% and knowledge of avulsed permanent and primary teeth from 8% to 71%. Knowledge of how to clean an avulsed tooth improved from 5% to 93%. The knowledge level on the importance of extra‐alveolar time before replantation increased from 1% to 74% and knowledge of a suitable storage medium for the avulsed tooth improved from 4% to 86%. Many avulsed permanent teeth in school children can be saved by replantation if school teachers learn what to do when a tooth is avulsed. A lecture followed by discussion proved to be an effective and efficient method of intervention to enhance the knowledge level of teachers so that proper dental first‐aid procedures can be achieved.
An evidence‐based appraisal of splinting luxated, avulsed and root‐fractured teeth
Authors: Kahler Bill , Heithersay Geoffrey S
Published: October 2007

Abstract –  The evidence‐based methodology involves framing a well defined PICO (problem, intervention, comparison and outcome) question related to a clinical problem and then comprehensively searching for the evidence, which is evaluated to appraise the value of the treatment intervention. For this systematic review of splinting of teeth that have been luxated, avulsed or root‐fractured, the clinical PICO question is (P) what are splinting intervention decisions for luxated, avulsed and root‐fractured teeth (I) considering that the splinting intervention choice may include (i) no splinting, (ii) rigid or functional splinting for the different types of trauma and (iii) different durations of the splinting period (C) when comparing these splinting choices for the different types of trauma and their effect on (O) healing outcomes for the teeth. A keyword search of PubMed was used. Reference lists from identified articles and dental traumatology texts were also appraised. The inclusion criterion for this review was either a multivariate analysis or controlled stratified analyses as many variables have the potential to confound the assessment and evaluation of healing outcomes for teeth that have been luxated, avulsed or root‐fractured. A positive statistical test is not proof of a causal conclusion, as a positive statistical relationship can arise by chance, and so this review also appraises animal studies that reportedly explain biological mechanisms that relate to healing outcomes of splinted teeth. The clinical studies were ranked using the ‘Centre of Evidence‐based Medicine’ categorization (levels 1–5). All 12 clinical studies selected were ranked as level 4. The studies generally indicate that the prognosis is determined by the type of injury rather than factors associated with splinting. The results indicate that the types of splint and the fixation period are generally not significant variables when related to healing outcomes. This appraisal identified difficulties in the design of animal experimentation to correctly simulate some dental injuries. Some of the studies employed rigid splinting techniques, which are not representative of current recommendations. Recommended splinting treatment protocols for teeth that have been luxated, avulsed or root‐fractured teeth are formulated on the strength of research evidence. Despite the ranking of these studies in this appraisal as low levels of evidence, these recommendations should be considered ‘best practice’, a core philosophy of evidence‐based dentistry.
Retinoic acid metabolism blocking agents (RAMBAs): a new paradigm in the treatment of hyperkeratotic disorders
Authors: Verfaille Christel J. , Borgers Marcel , Van Steensel Maurice A. M.
Published: October 2007

Synthetic vitamin A derivatives, retinoids,have long been the mainstay of treatment for several disorders of keratinization, notably the ichthyoses and severe acne. Some forms of psoriasis also respond well. Their considerable power comes at a price.They have dose‐limiting side effects and can be highly teratogenic, limiting their use in women of childbearing age.Thus, retinoids are used less often than their potential would warrant. However, the recent development of compounds that block the catabolism of endogenous vitamin A, called Retinioic Acid Metabolism Blocking Agents or RAMBAs, offers new possibilities. With these drugs, retinoid effects with less side effects and a reduction of the post‐treatment teratogenicity period due to their favourable pharmacokinetic profile might be expected. In this review, we discuss how retinoids work, how they are metabolized and how RAMBAs influence this process.We also review the presently available data from clinical trials with RAMBAs.
Molecular and genetic characterization of osmosensing and signal transduction in the nematode Caenorhabditis elegans
Authors: Choe Keith P. , Strange Kevin
Published: October 2007

Osmotic homeostasis is a fundamental requirement for life. In general, the effector mechanisms that mediate cellular and extracellular osmoregulation in animals are reasonably well defined. However, at the molecular level, little is known about how animals detect osmotic and ionic perturbations and transduce them into regulatory responses. The nematode Caenorhabditis elegans provides numerous powerful experimental advantages for defining the genes and integrated gene networks that underlie basic biological processes. These advantages include a fully sequenced and well‐annotated genome, forward and reverse genetic and molecular tractability, and a relatively simple anatomy. C. elegans normally inhabits soil environments where it is exposed to repeated osmotic stress. In the laboratory, nematodes readily acclimate to and recover from extremes of hypertonicity. We review recent progress in defining the molecular mechanisms that underlie osmosensing and associated signal transduction in C. elegans. Some of these mechanisms are now known to be highly conserved. Therefore, studies of osmosensing in nematodes have provided, and will undoubtedly continue to provide, new insights into similar processes in more complex organisms including mammals.
Osmotic stress sensing and signaling in fishes
Authors: Fiol Diego F. , Kültz Dietmar
Published: October 2007

In their aqueous habitats, fish are exposed to a wide range of osmotic conditions and differ in their abilities to respond adaptively to these variations in salinity. Fish species that inhabit environments characterized by significant salinity fluctuation (intertidal zone, estuaries, salt lakes, etc.) are euryhaline and able to adapt to osmotic stress. Adaptive and acclimatory responses of fish to salinity stress are based on efficient mechanisms of osmosensing and osmotic stress signaling. Multiple osmosensors, including calcium sensing receptor likely act in concert to convey information about osmolality changes to downstream signaling and effector mechanisms. The osmosensory signal transduction network in fishes is complex and includes calcium, mitogen‐activated protein kinase, 14‐3‐3 and macromolecular damage activated signaling pathways. This network controls, among other targets, osmosensitive transcription factors such as tonicity response element binding protein and osmotic stress transcription factor 1, which, in turn, regulate the expression of genes involved in osmotic stress acclimation. In addition to intracellular signaling mechanisms, the systemic response to osmotic stress in euryhaline fish is coordinated via hormone‐ and paracrine factor‐mediated extracellular signaling. Overall, current insight into osmosensing and osmotic stress‐induced signal transduction in fishes is limited. However, euryhaline fish species represent excellent models for answering critical emerging questions in this field and for elucidating the underlying molecular mechanisms of osmosensory signal transduction.
CpG and LPS can interfere negatively with prion clearance in macrophage and microglial cells
Authors: Gilch Sabine , Schmitz Frank , Aguib Yasmine , Kehler Claudia , Bülow Sigrid , Bauer Stefan , Kremmer Elisabeth , Schätzl Hermann M.
Published: October 2007

Cells of the innate immune system play important roles in the progression of prion disease after peripheral infection. It has been found in vivo and in vitro that the expression of the cellular prion protein (PrPc) is up‐regulated on stimulation of immune cells, also indicating the functional importance of PrPc in the immune system. The aim of our study was to investigate the impact of cytosine‐phosphate‐guanosine‐ and lipopolysaccharide‐induced PrPc up‐regulation on the uptake and processing of the pathological prion protein (PrPSc) in phagocytic innate immune cells. For this purpose, we challenged the macrophage cell line J774, the microglial cell line BV‐2 and primary bone marrow‐derived macrophages in a resting or stimulated state with various prion strains, and monitored the uptake and clearance of PrPSc. Interestingly, stimulation led either to a transient increase in the level of PrPSc relative to unstimulated cells or to a decelerated degradation of PrPSc. These features were dependent on cell type and prion strain. Our data indicate that the stimulation of innate immune cells may be able to support transient prion propagation, possibly explained by an increased PrPc cell surface expression in stimulated cells. We suggest that stimulation of innate immune cells can lead to an imbalance between the propagation and degradation of PrPSc.
Identification of three phases in Onconase refolding
Authors: Schulenburg Cindy , Martinez‐Senac Maria M. , Löw Christian , Golbik Ralph , Ulbrich‐Hofmann Renate , Arnold Ulrich
Published: October 2007

Onconase is an extremely stable member of the RNase A superfamily. The increase in the thermodynamic stability by 20 kJ·mol−1in comparison to RNase A was expected to result in altered folding behavior. Despite the lack ofcis‐Pro residues in native Onconase, refolding at low concentrations of guanidine hydrochloride was complex and showed three kinetic phases (fast, medium, and slow), with rate constants differing by a factor of about 10 each. None of the phases could be accelerated by peptidyl–prolylcis–transisomerases, pointing to the absence of kinetic phases that are limited by Pro isomerization. The detailed analysis by various probes indicates that the burial of the N‐terminal Trp3, which is associated with the restoration of the active site, occurs in the slow phase, i.e. in the last step of refolding. Evidently, in contrast to the folding of RNase A, there is no catalytically active native‐like intermediate in the folding of Onconase.
13C Isotopologue editing of FMN bound to phototropin domains
Authors: Eisenreich Wolfgang , Joshi Monika , Illarionov Boris , Richter Gerald , Römisch‐Margl Werner , Müller Franz , Bacher Adelbert , Fischer Markus
Published: October 2007

The plant blue light receptor phototropin comprises a protein kinase domain and two FMN‐binding LOV domains (LOV1 and LOV2). Blue light irradiation of recombinant LOV domains is conducive to the addition of a cysteinyl thiolate group to carbon 4a of the FMN chromophore, and spontaneous cleavage of that photoadduct completes the photocycle of the receptor. The present study is based on 13C NMR signal modulation observed after reconstitution of LOV domains of different origins with random libraries of 13C‐labeled FMN isotopologues. Using this approach, all 13C signals of FMN bound to LOV1 and LOV2 domains of Avena sativa and to the LOV2 domain of the fern, Adiantum capillus‐veneris, could be unequivocally assigned under dark and under blue light irradiation conditions. 13C Chemical shifts of FMN are shown to be differently modulated by complexation with the LOV domains under study, indicating slight differences in the binding interactions of FMN and the apoproteins.
Synthesis and characterization of a new and radiolabeled high‐affinity substrate for H+/peptide cotransporters
Authors: Knütter Ilka , Hartrodt Bianka , Tóth Géza , Keresztes Attila , Kottra Gabor , Mrestani‐Klaus Carmen , Born Ilona , Daniel Hannelore , Neubert Klaus , Brandsch Matthias
Published: October 2007

In this study we described the design, rational synthesis and functional characterization of a novel radiolabeled hydrolysis‐resistant high‐affinity substrate for H+/peptide cotransporters.l‐4,4′‐Biphenylalanyl–l‐Proline (Bip‐Pro) was synthesized according to standard procedures in peptide chemistry. The interaction of Bip‐Pro with H+/peptide cotransporters was determined in intestinal Caco‐2 cells constitutively expressing human H+/peptide cotransporter 1 (PEPT1) and in renal SKPT cells constitutively expressing rat H+/peptide cotransporter 2 (PEPT2). Bip‐Pro inhibited the [14C]Gly‐Sar uptake via PEPT1 and PEPT2 with exceptional high affinity (Ki = 24 µmand 3.4 µm, respectively) in a competitive manner. By employing the two‐electrode voltage clamp technique inXenopus laevisoocytes expressing PEPT1 or PEPT2 it was found that Bip‐Pro was transported by both peptide transporters although to a much lower extent than the reference substrate, Gly‐Gln. Bip‐Pro remained intact to > 98% for at least 8 h when incubated with intact cell monolayers. Bip‐[3H]Pro uptake into SKPT cells was linear for up to 30 min and pH dependent with a maximum at extracellular pH 6.0. Uptake was strongly inhibited, not only by unlabeled Bip‐Pro but also by known peptide transporter substrates such as dipeptides, cefadroxil, Ala‐4‐nitroanilide and δ‐aminolevulinic acid, but not by glycine. Bip‐Pro uptake in SKPT cells was saturable with a Michaelis–Menten constant (Kt) of 7.6 µmand a maximal velocity (Vmax) of 1.1 nmol·30 min−1·mg of protein−1. Hence, the uptake of Bip‐Pro by PEPT2 is a high‐affinity, low‐capacity process in comparison to the uptake of Gly‐Sar. We conclude that Bip‐[3H]Pro is a valuable substrate for both mechanistic and structural studies of H+/peptide transporter proteins.
Kinetically controlled refolding of a heat‐denatured hyperthermostable protein
Authors: Koutsopoulos Sotirios , van der Oost John , Norde Willem
Published: October 2007

The thermal denaturation of endo‐β‐1,3‐glucanase from the hyperthermophilic microorganism Pyrococcus furiosus was studied by calorimetry. The calorimetric profile revealed two transitions at 109 and 144 °C, corresponding to protein denaturation and complete unfolding, respectively, as shown by circular dichroism and fluorescence spectroscopy data. Calorimetric studies also showed that the denatured state did not refold to the native state unless the cooling temperature rate was very slow. Furthermore, previously denatured protein samples gave well‐resolved denaturation transition peaks and showed enzymatic activity after 3 and 9 months of storage, indicating slow refolding to the native conformation over time.
The lactate dehydrogenases encoded by the ldh and ldhB genes in Lactococcus lactis exhibit distinct regulation and catalytic properties − comparative modeling to probe the molecular basis
Authors: Gaspar Paula , Neves Ana R. , Shearman Claire A. , Gasson Michael J. , Baptista António M. , Turner David L. , Soares Cláudio M. , Santos Helena
Published: October 2007

Lactococcus lactis FI9078, a construct carrying a disruption of the ldh gene, converted approximately 90% of glucose into lactic acid, like the parental strain MG1363. This unexpected lactate dehydrogenase activity was purified, and ldhB was identified as the gene encoding this protein. The activation of ldhB was explained by the insertion of an IS905‐like element that created a hybrid promoter in the intergenic region upstream of ldhB. The biochemical and kinetic properties of this alternative lactate dehydrogenase (LDHB) were compared to those of the ldh‐encoded enzyme (LDH), purified from the parental strain. In contrast to LDH, the affinity of LDHB for NADH and the activation constant for fructose 1,6‐bisphosphate were strongly dependent on pH. The activation constant increased 700‐fold, whereas the Km for NADH increased more than 10‐fold, in the pH range 5.5–7.2. The two enzymes also exhibited different pH profiles for maximal activity. Moreover, inorganic phosphate acted as a strong activator of LDHB. The impact of replacing LDH by LDHB on the physiology of L. lactis was assessed by monitoring the evolution of the pools of glycolytic intermediates and cofactors during the metabolism of glucose by in vivo NMR. Structural analysis by comparative modeling of the two proteins showed that LDH has a slightly larger negative charge than LDHB and a greater concentration of positive charges at the interface between monomers. The calculated pH titration curves of the catalytic histidine residues explain why LDH maintains its activity at low pH as compared to LDHB, the histidines in LDH showing larger pH titration ranges.
Small heat shock protein Hsp27 prevents heat‐induced aggregation of F‐actin by forming soluble complexes with denatured actin
Authors: Pivovarova Anastasia V. , Chebotareva Natalia A. , Chernik Ivan S. , Gusev Nikolai B. , Levitsky Dmitrii I.
Published: October 2007

Previously, we have shown that the small heat shock protein with apparent molecular mass 27 kDa (Hsp27) does not affect the thermal unfolding of F‐actin, but effectively prevents aggregation of thermally denatured F‐actin [Pivovarova AV, Mikhailova VV, Chernik IS, Chebotareva NA, Levitsky DI & Gusev NB (2005) Biochem Biophys Res Commun331, 1548–1553], and supposed that Hsp27 prevents heat‐induced aggregation of F‐actin by forming soluble complexes with denatured actin. In the present work, we applied dynamic light scattering, analytical ultracentrifugation and size exclusion chromatography to examine the properties of complexes formed by denatured actin with a recombinant human Hsp27 mutant (Hsp27–3D) mimicking the naturally occurring phosphorylation of this protein at Ser15, Ser78, and Ser82. Our results show that formation of these complexes occurs upon heating and accompanies the F‐actin thermal denaturation. All the methods show that the size of actin–Hsp27‐3D complexes decreases with increasing Hsp27‐3D concentration in the incubation mixture and that saturation occurs at approximately equimolar concentrations of Hsp27‐3D and actin. Under these conditions, the complexes exhibit a hydrodynamic radius of ∼ 16 nm, a sedimentation coefficient of 17–20 S, and a molecular mass of about 2 MDa. It is supposed that Hsp27‐3D binds to denatured actin monomers or short oligomers dissociated from actin filaments upon heating and protects them from aggregation by forming relatively small and highly soluble complexes. This mechanism might explain how small heat shock proteins prevent aggregation of denatured actin and by this means protect the cytoskeleton and the whole cell from damage caused by accumulation of large insoluble aggregates under heat shock conditions.
Collpas: Activity Hotspots for Frugivorous Bats (Phyllostomidae) in the Peruvian Amazon
Authors: Bravo Adriana , Harms Kyle E. , Stevens Richard D. , Emmons Louise H.
Published: October 2007

In the SE Peruvian Amazon, large numbers of frugivorous bats regularly visit natural forest clearings known locally as collpas (which are also referred to as clay licks or mineral licks). Bats arrive at collpas to drink water that has accumulated in depressions created by larger geophagous mammals that consume exposed soil. Although collpa visitation is common, little is known about its causes and its ecological implications for the bat community. We compared patterns of use of collpas and non‐collpa forest sites by bats in SE Peru. We mist netted bats at collpas and non‐collpa sites during the dry season and compared abundance, species richness, species composition, sex ratio, and reproductive condition. More species were captured at collpas than at non‐collpa sites, and collpas were visited almost exclusively by frugivores. Overall, bat‐capture frequency and combined frugivorous bat‐capture frequency were higher at collpas than at non‐collpa sites, although some species of frugivorous bats were captured more frequently at non‐collpa sites than at collpas (e.g., Carollia spp.). Irrespective of capture site, more female bats were pregnant or lactating than not, but there was a distinct female sex bias in bats that visited collpas: 70 percent of bats captured at collpas were female, whereas 44 percent of bats captured away from collpas were female. These patterns suggest that collpas may provide important resources for frugivorous bats in SE Peru, just as they are thought to provide important resources to the vertebrates that consume collpa soils. Accordingly, collpas are important conservation targets in the region.
Sexual Systems and Ecological Correlates in an Azonal Tropical Forests, SW China
Authors: Chen Xin‐Sheng , Li Qing‐Jun
Published: October 2007

Unlike the seriate lowland rain forests in SE Asia, the tropical vegetation of Xishuangbanna (SW China) has developed in habitats with comparatively lower temperatures and precipitation. Consequently, although most of the families and genera of the flora are components of tropical ecosystems, many have reached their distribution limits in latitude. Selection pressures on sexual systems in these environments may be different from that experienced in lowland tropical regions. Here, we examine the sexual systems of 685 species of flowering plants belonging to 109 families and 356 genera based on 42 plots with a total area of 15.4 ha and compare our results with surveys of sexual systems from other tropical ecosystems. Among these species, 60.6 percent were hermaphroditic, 14.3 percent were monoecious, and 25.1 percent were dioecious. The percentage of dioecious sexual system among tree species (26.1%) was similar or higher than that of other tropical tree floras. Monoecy was significantly associated with the tree growth form and was relatively common in seasonal forest vegetation. Sexual systems involving unisexual flowers (dicliny) are particularly well represented in the tropical forests of Xishuangbanna accounting for 39.4 percent of all species surveyed. This pattern may be associated with the prevalence of relatively small inconspicuous flowers in the tropical forests of SE Asia and their correlation with diclinous sexual systems generally.
Community Structure of Large Mammals in Tropical Montane and Lowland Forest in the Tenasserim‐Dawna Mountains, Thailand
Authors: Steinmetz Robert , Chutipong Wanlop , Seuaturien Naret , Chirngsaard Erb
Published: October 2007

Montane evergreen forest in SE Asia is structurally and floristically different from lowland habitats. The response of large mammals to this variation is largely unexplored. We used sign transects to compare community structure of large mammals in montane (>1100 m), and lowland (<1100 m) forest types over 4 yr in western Thailand. Relative abundance of most ungulate species was significantly higher in lowland forest, except for elephant (Elephas maximus) and tapir (Tapirus indicus), which were most abundant in montane forest (based on chi‐square tests of sign encounter rates). Sexual segregation was apparent for gaur (Bos gaurus): breeding herds were concentrated in the lowlands, whereas single males were most abundant in montane forest. Large cat abundance was similar in both elevation zones. Tapir, single gaur, and bears (Ursus spp.) characterized the montane mammal community, whereas most other ungulate species and social groups were indicative of lowland forest (based on discriminant function analysis). Results pertain only to the dry season; seasonal movements could alter the patterns we observed. Differences in community structure between elevation zones are hypothesized to result from differences in habitat structure, resource availability, and human impacts. Lowland forests provide bamboo, grass, and mineral licks, probably accounting for higher ungulate densities despite higher levels of hunting. These resources are scarce in montane forest. However, montane forest functions as a refuge for at least three globally threatened large mammal species, because commercial hunting is concentrated in the more accessible lowlands.
Microwave‐Assisted Solid‐Phase Peptide Synthesis Utilizing N‐Fmoc‐Protected (α‐aminoacyl)benzotriazoles
Authors: Katritzky Alan R. , Khashab Niveen M. , Yoshioka Megumi , Haase Danniebelle N. , Wilson Krista R. , Johnson Jodie V. , Chung Alfred , Haskell‐Luevano Carrie
Published: October 2007

A novel microwave‐assisted solid‐phase peptide synthesis utilizing N‐Fmoc‐protected(α‐aminoacyl)benzotriazoles was applied in the preparation of tri‐, tetra‐, penta‐, hexa‐, and heptapeptides in 71% average crude yield.
Multi‐way Analysis of Quantum Topological Molecular Similarity Descriptors for Modeling Acidity Constant of Some Phenolic Compounds
Authors: Esteki Mahnaz , Hemmateenejad Bahram , Khayamian Taghi , Mohajeri Afshan
Published: October 2007

Three‐way analyses of quantum topological molecular similarity descriptors were used for quantitative structure property relationship modeling of the acidity constant of some phenol derivatives. A three‐way data was built for different molecules by constructing a data matrix for each molecule. The matrix was produced by considering different bonds in each molecule and different descriptors in each bond. The three‐way models parallel factor analysis and N‐way partial least squares, and two‐way models including partial least squares were used for modeling structure–acidity relationships. Comparison of the results showed that the three‐way arrays produced more predictive models with lower over‐fitting. The bilinear partial least square model resulted in a biased estimation of acidity constant of prediction set with average relative error of prediction of 1.87%, whereas that obtained by parallel factor analysis and N‐way partial least squares was near to zero (i.e. −0.41 and −0.33, respectively). Additionally, the three‐way methods allowed investigating the significant impact of different bonds and different descriptors using leverages of the parallel factor analysis loadings.
Word Classes
Authors: Rijkhoff Jan
Published: October 2007

This article1provides an overview of recent literature and research on word classes, focusing in particular on typological approaches to word classification. The cross‐linguistic classification of word class systems (or parts‐of‐speech systems) presented in this article is based on statements found in grammatical descriptions of some 50 languages, which together constitute a representative sample of the world's languages. It appears that there are both quantitative and qualitative differences between word class systems of individual languages. Whereas some languages employ a parts‐of‐speech system that includes the categories verb, noun, adjective and adverb, other languages may use only a subset of these four lexical categories. Furthermore, quite a few languages have a major word class whose members cannot be classified in terms of the categories verb–noun–adjective–adverb, because they have properties that are strongly associated with at least two of these four traditional word classes (e.g. adjective and adverb). Finally, this article discusses some of the ways in which word class distinctions interact with other grammatical domains, such as syntax and morphology.
Bioaerosol sampling for the detection of aerosolized influenza virus
Authors: Blachere Francoise M. , Lindsley William G. , Slaven James E. , Green Brett J. , Anderson Stacey E. , Chen Bean T. , Beezhold Don H.
Published: October 2007

Background Influenza virus was used to characterize the efficacy of a cyclone‐based, two‐stage personal bioaerosol sampler for the collection and size fractionation of aerosolized viral particles.

Methods A Collison single‐jet nebulizer was used to aerosolize the attenuated FluMist® vaccine into a calm‐air settling chamber. Viral particles were captured with bioaerosol samplers that utilize 2 microcentrifuge tubes to collect airborne particulates. The first tube (T1) collects particles greater than 1.8 μm in diameter, while the second tube (T2) collects particles between 1.0 and 1.8 μm, and the back‐up filter (F) collects submicron particles. Following aerosolization, quantitative PCR was used to detect and quantify H1N1 and H3N2 influenza strains.

Results Based on qPCR results, we demonstrate that aerosolized viral particles were efficiently collected and separated according to aerodynamic size using the two‐stage bioaerosol sampler. Most viral particles were collected in T2 (1‐1.8 μm) and on the back‐up filter (< 1 μm) of the bioaerosol sampler. Furthermore, we found that the detection of viral particles with the two‐stage sampler was directly proportional to the collection time. Consequently, viral particle counts were significantly greater at 40 minutes in comparison to 5, 10 and 20 minute aerosol collection points.

Conclusions Due to a lack of empirical data, aerosol transmission of influenza is often questioned. Using FluMist®, we demonstrated that a newly developed bioaerosol sampler is able to recover and size fractionate aerosolized viral particles. This sampler should be an important tool for studying viral transmission in clinical settings and may significantly contribute towards understanding the modes of influenza virus transmission.
DNA‐ligand Binding Mode Discrimination by Characterizing Fluorescence Resonance Energy Transfer Through Lifetime Measurements with Picosecond Resolution
Authors: Nardo Luca , Bondani Maria , Andreoni Alessandra
Published: October 2007

We describe a method for distinguishing between minor groove binders and base intercalators that is based on measurements of the fluorescence lifetime of a donor (D) in the presence of an acceptor (A). The D–A pair is separated by a short double helix DNA with which the ligands interact. By plotting the D fluorescence lifetime as a function of the ligand‐to‐base pair concentration ratio we find a clear signature that distinguishes between the two binding mechanisms: minor groove binding induces an asymptotic decrease of the D fluorescence lifetime, while intercalation gives a monotonically increasing lifetime and the appearance of an additional short lifetime. We assayed Quinacrine, Hoechst and 4′–6′diamidine‐2‐phenyl indole, which in control experiments performed on oligodeoxyribonucleotides (oligos) lacking the A are demonstrated not to interfere with the D fluorescence. The changes in fluorescence lifetimes measured in the case of dual‐labeled oligos are thus caused by structural changes in the DNA that modify the D–A distance. The appearance of the short‐lived transient in the fluorescence decay of Ds attached to dual‐labeled oligos upon binding of an intercalator can be interpreted as denaturation.
OT‐674 Suppresses Photooxidative Processes Initiated by an RPE Lipofuscin Fluorophore
Authors: Zhou Jilin , Jang Young P. , Chang Stanley , Sparrow Janet R.
Published: October 2007

The pathological processes involved in age‐related macular degeneration (AMD) include retinal pigment epithelial (RPE) cell degeneration; oxidative mechanisms likely contribute to the demise of these cells. Indeed, RPE cells may be particularly susceptible to photooxidative mechanisms since they accumulate retinoid‐derived photoreactive compounds that constitute the lipofuscin of the cell. Thus we undertook to test the capacity of OT‐674, the reduction product (Tempol‐H) of the nitroxide Tempol, to suppress photooxidative processes initiated by the RPE lipofuscin fluorophore A2E. Accordingly, when ARPE‐19 cells that had accumulated A2E were irradiated at 430 nm, pretreatment with OT‐674 (0.01–10 mm) was found to confer a resistance to cell death. Monitoring by quantitative HPLC also showed that OT‐674 reduced A2E photooxidation in a cell‐free system. Moreover, when presented with a singlet oxygen generator, OT‐674 served as a quencher of singlet oxygen that was more effective than Trolox and α‐tocopherol. We conclude that OT‐674 is a potent antioxidant that suppresses photooxidative processes generated in cultured RPE cells by the lipofuscin fluorophore A2E. As oxidative damage to RPE cells is considered to be a risk factor for AMD, antioxidant therapy with OT‐674 may serve a protective role.
Identification of Sites Within a Monomeric Red Fluorescent Protein that Tolerate Peptide Insertion and Testing of Corresponding Circular Permutations
Authors: Li Yankun , Sierra Aillette M. , Ai Hui‐wang , Campbell Robert E.
Published: October 2007

In recent years the class of known fluorescent proteins (FPs) has dramatically expanded as an ever‐increasing numbers of variants and homologs of the green fluorescent protein (GFP) from Aequorea jellyfish have been either engineered in the lab or discovered in other marine organisms. The red fluorescent protein (RFP) from Discosoma coral (also known as dsFP583 and DsRed) has proven to be a particularly fruitful progenitor of variants with biochemical and spectroscopic properties conducive to applications in live cell imaging. We have investigated the tolerance of an engineered monomeric descendent of Discosoma RFP, known as mCherry, towards peptide insertion and circular permutation. Starting from a random library of insertion variants, we identified six genetically distinct sites localized in three different loops where a sequence of five residues could be inserted without abolishing the ability of the protein to form its intrinsic red fluorescent chromophore. For each of these insertion variants, a corresponding circular permutation variant was created in which the original N‐ and C‐termini were connected by a six‐residue linker and new termini were introduced at the site of the insertion. All six circular permutation variants had significantly diminished brightness relative to the analogous insertion variants. The most promising circular permutation variant has termini at the position corresponding to residue 184 of mCherry and retains 37% of the intrinsic fluorescent brightness of mCherry. These circularly permuted variants may serve as the foundation for construction of genetically encoded Ca2+ sensors analogous to the previously reported camgaroo, pericam and G‐CaMP sensors based on variants of Aequorea GFP.