bluuebunny/crossref_metadata_2025 huggingface dataset:
Jaundice in malaria
Authors: ANAND ANIL C , PURI PANKAJ
Published: August 2005

Jaundice is not an unusual accompaniment of malaria. It can occur due to intravascular hemolysis, disseminated intravascular coagulation, and, rarely, ‘malarial hepatitis’. Although the primary schizogony of the malarial parasite always leads to the rupture of the infected hepatocyte, alteration of the hepatic functions is uncommonly recorded due to this event. Histologically, the hepatitis or the actual inflammation in the liver has never been demonstrated. Nonetheless, the term ‘malarial hepatitis’ (MH) has been used in the literature to describe the occurrence of hepatocellular jaundice in patients with Plasmodium falciparum infection. The authors’ own data and review of the literature indicate that it is not an uncommon entity. In endemic areas, jaundice is seen in approximately 2.5% of patients with falciparum malaria. It also appears to be a heterogeneous syndrome and one can recognize two clinical subsets. In one group there was an acute, virulent presentation with coma, renal failure and in some cases even hemorrhagic manifestations. It is only in this setting that jaundice signified a ‘severe’ disease as noted by the World Health Organization action program. This presentation is often confused with acute viral hepatitis and acute hepatic failure in non‐endemic areas, but can be clinically differentiated.

© 2005 Blackwell Publishing Asia Pty Ltd
Association between adenomas of rectosigmoid colon and metabolic syndrome features in a Chinese population
Authors: WANG YA‐YU , LIN SHIH‐YI , LAI WEN‐AN , LIU PI‐HWA , SHEU WAYNE HUEY‐HERNG
Published: August 2005

Background and Aims:  Metabolic syndrome (MS) consists of a cluster of diseases, including obesity, dyslipidemia, hyperglycemia and high blood pressure. The purpose of the present study was to assess the association of MS with adenomas of the rectosigmoid colon, a well‐established precancerous lesion.

Methods:  A total of 4938 Taiwanese patients (2891 men and 2047 women with a mean age of 50.1 years), who had a physical examination at our hospital between January 2001 and October 2002, were enrolled in this study. All patients underwent a sigmoidoscopic examination to 60 cm from the anus. A modified National Cholesterol Education Program (NCEP) definition of MS was used in this study, in which body mass index (BMI) was substituted for the waist circumference measurement.

Results:  Overall, 14% of patients had an elevated fasting glucose, 27% had high blood pressure, 14% had an increased triglyceride (TG) level, 8% had low high density lipoprotein (HDL) cholesterol, and 18% were obese. Rectosigmoid polyps were present in 17% of patients, among whom 568 received polypectomy. Pathological findings were hyperplastic in 138 subjects, adenomas in 341, carcinomas in 10, and other benign lesions in 79. In patients without polyps, the adjusted mean TG level and calculated BMI level were lower than those in patients with adenomas. No such difference existed, however, between patients without polyps and those with hyperplastic polyps. The odds ratio of adenomas in situ as compared to either a polyp‐free state or the presence of hyperplastic polyps increased significantly with the number of MS diagnostic criteria the patient exhibited.

Conclusion:  Our study shows that MS is associated with rectosigmoid adenomas in a Chinese population. In patients with rectosigmoid polyps, the coexistence of MS may portend an increased risk of adenomas.

© 2005 Blackwell Publishing Asia Pty Ltd
Management of symptoms in step‐down therapy of gastroesophageal reflux disease
Authors: MINE SHINICHIRO , IIDA TAKESHI , TABATA TAKAHIRO , KISHIKAWA HIROFUMI , TANAKA YOSHIYA
Published: August 2005

Objective:  Majority of studies on gastroesophageal reflux disease (GERD) that include patients with or without erosive disease have documented the efficacy of proton pump inhibitors (PPIs) as well as their superiority to H2‐receptor antagonist (H2‐RA). The purpose of this study was to clarify the difference in quality of GERD treatment with PPIs and H2‐RA in step‐down protocol using lansoprazole.

Methods:  Forty‐three patients with reflux esophagitis were randomly divided into three groups and assessed by severity score; group 1 received 30 mg lansoprazole initially and maintenance therapy with a standard dose H2‐RA; group 2 received 30 mg of lansoprazole initially and maintenance therapy of 15 mg lansoprazole; and group 3 received 15 mg of lansoprazole once daily for 16 weeks. If the patients experienced symptomatic recurrence while on H2‐RA, they were switched to PPI maintenance.

Results:  Heartburn, regurgitation and dysphagia were hardly found in any group at 8 weeks after 15 mg or 30 mg lansoprazole treatment. After 8 weeks, however, heartburn and regurgitation recurred at 50% and 78.6%, respectively, in the stepped down to famotidine group, and quality of life (QOL) was significantly impaired. Endoscopic ultrasonography (EUS) analysis showed reduction of the submucosal layer without any change in the mucosal surface in the stepped down to famotidine group.

Conclusions:  Step‐down lansoprazole therapy is considered very effective in terms of rapid effect, long‐term effect and high quality GERD treatment.

© 2005 Blackwell Publishing Asia Pty Ltd
Mutations in the NS5B region of the hepatitis C virus genome correlate with clinical outcomes of interferon‐alpha plus ribavirin combination therapy
Authors: HAMANO KOSEI , SAKAMOTO NAOYA , ENOMOTO NOBUYUKI , IZUMI NAMIKI , ASAHINA YASUHIRO , KUROSAKI MASAYUKI , UEDA ERI , TANABE YOKO , MAEKAWA SHINYA , ITAKURA JUN , WATANABE HIDEKI , KAKINUMA SEI , WATANABE MAMORU
Published: August 2005

Background and Aim:  Combination treatments of interferon‐alpha (IFN) and ribavirin (RBV) are more effective than those of IFN alone in hepatitis C virus (HCV) infection. However, mechanisms of the action of the combination regimen are not well understood. To elucidate the viral genetic basis of IFN plus RBV combination therapy, genetic variabilities of HCV‐1b were analyzed.

Methods:  We performed pair‐wise comparisons of full‐length HCV genomic sequences in three patients’ sera before and after initiation of IFN plus RBV treatment. Subsequently, we analyzed amino acid sequences of the NS5B region, which codes for the viral RNA‐dependent RNA polymerase, and compared these with the outcomes of the therapy in 81 patients.

Results:  Analysis of the entire HCV sequence in patients who received IFN plus RBV therapy did not show consistent amino acid changes between before and after the initiation of the therapy. NS5B sequence analyses revealed that mutations at positions 300–358 of NS5B, including polymerase motif B to E, occurred more frequently in a group of patients exhibiting a sustained viral response (SVR) or an end‐of‐treatment response (ETR) compared with a group of patients exhibiting a non‐response (NR). Closer examination revealed that mutations at aa 309, 333, 338 and 355 of NS5B occurred significantly more frequently in the SVR plus ETR group than in the NR group (P = 0.0004). Multivariate analysis showed that the number of mutations at these four sites was an independent predictor of SVR plus ETR versus NR.

Conclusions:  Particular amino acid changes in the NS5B region of HCV may correlate with outcomes of IFN plus RBV combination therapy.

© 2005 Blackwell Publishing Asia Pty Ltd
Recovery of the water content of hydrogel contact lenses after use
Authors: Velasco Cabrera Josefa , García Velasco María José
Published: August 2005

The aim of the present study is to determine the amount and time of water‐content recovery of ionic contact lenses (Surevue® and Acuvue®) and non‐ionic contact lenses (Soflens 38®, Soflens 66® and Optima 38®) when submerged in maintenance solution for 9 h. Using a hand‐held refractometer, we measured the water content of the lenses upon removal from the eye, and after 15, 30, 45 min, 1, 2 and 9 h in soaking solution. Both ionic lenses presented pre‐wear water content of 58%, while two of the non‐ionic ones (Soflens 38® and Optima 38®) registered 38.6% and the third (Soflens 66®) had 66%. We found a significant increase (p < 0.05) in water content after submersion in the Opti‐Free® solution for all the time periods studied and for all lenses. The water‐content recovery was faster in the non‐ionic lenses (Soflens 38®, Soflens 66® and Optima 38®) than in the ionic ones (Surevue® and Acuvue®), especially at 15 min. After 9 h in the soaking solution, the Surevue® Acuvue®, Soflens 38®, Soflens 66® and Optima 38® lenses reached water‐content recovery values of 99.7%, 99.6%, 99.8%, 99.8% and 99.6%, respectively, without significant differences (p > 0.05) between ionic and non‐ionic lenses, although the non‐ionic lenses reached slightly higher water‐content values at all the times studied. These results indicate that when the refractometer technique is used to measure water content, the lens types used in this study regain their initial water‐content values after 9 h in soaking solution. These data indicate the time needed for hydrogel contact lenses to reach their maximum water content after removal from the eye and submersion in maintenance solution. By ensuring maximum water content and minimum reduction of oxygen for the cornea, the specialist can help avoid clinical signs and symptoms related to low water content in the lenses.
Myopia and associated pathological complications
Authors: Saw Seang‐Mei , Gazzard Gus , Shih‐Yen Edwin Chan , Chua Wei‐Han
Published: August 2005

Besides the direct economic and social burden of myopia, associated ocular complications may lead to substantial visual loss. In several population and clinic‐based cohorts, case–control and cross‐sectional studies, higher risks of posterior subcapsular cataract, cortical and nuclear cataract in myopic patients were reported. Patients with high myopia (spherical equivalent at least –6.0 D) are more susceptible to ocular abnormalities. The prevalent risks of glaucoma were higher in myopic adults, and risks of chorioretinal abnormalities such as retinal detachment, chorioretinal atrophy and lacquer cracks increased with severity of myopia and greater axial length. Myopic adults were more likely to have tilted, rotated, and larger discs as well as other optic disc abnormalities. Often, these studies support possible associations between myopia and specific ocular complications, but we cannot infer causality because of limitations in study methodology. The detection and treatment of possible pathological ocular complications is essential in the management of high myopia. The ocular risks associated with myopia should not be underestimated and there is a public health need to prevent the onset or progression of myopia.
The Proview Eye Pressure Monitor: influence of clinical factors on accuracy and agreement with the Goldmann tonometer
Authors: Herse Peter , Hans Avleen , Hall Julia , Langejans Jessica , Markoulli Maria
Published: August 2005

Purpose:  To investigate (i) the effect of probe position on the lid when using the Proview Eye Pressure Monitor (Proview) and (ii) the accuracy of the Proview and its agreement with the Goldmann applanation tonometer (GAT) in a normal population.

Methods:  Intraocular pressure (IOP) measurements were performed on 107 control subjects (mean 25 years) using the Proview and the GAT. The Proview probe was applied to two locations on the eyelid (superior nasal and superior temporal). The IOPs measured with both instruments were compared.

Results:  A total of 4.6% of young normal eyes could not perceive the phosphene. The mean Proview reading using the recommended nasal lid position was significantly higher (+2.5 mmHg) than that measured using the GAT. The position of the probe application was significant, with temporal lid application giving statistically significantly higher IOP readings than the recommended nasal lid application. The repeatability of Proview measurements was lower than the GAT (coefficients of repeatability of GAT and Proview nasal were 0.96 and 4.21 mmHg respectively). The limit of agreement between the GAT and the Proview nasal was low at ±7.95 mmHg.

Conclusion:  This study shows that the position of probe application can influence the measurements taken using the Proview. Application of the probe to the nasal superior lid (as recommended) gives the more repeatable and accurate results. Overall however the data indicate that the Proview is neither sufficiently accurate nor repeatable to be used in the detection and management of glaucoma. More work is needed in developing this interesting product.
Comparing glaucomatous optic neuropathy in primary open angle and chronic primary angle closure glaucoma eyes by optical coherence tomography
Authors: Sihota Ramanjit , Sony Parul , Gupta Viney , Dada Tanuj , Singh Rajvir
Published: August 2005

Purpose:  To comparatively evaluate the optic nerve head (ONH) using Optical Coherence Tomography (OCT) in normal subjects, primary open angle glaucoma (POAG) and chronic primary angle closure glaucoma (CPACG) patients.

Methods:  A total of 138 normal eyes (138 subjects) and 139 glaucomatous eyes (139 patients), were evaluated in this cross‐sectional observational study. The ONH was imaged on OCT using the optic disc scan. Disc area, cup area, rim area, vertical integrated rim area (VIRA), rim volume (horizontal integrated rim volume), average cup/disc ratio, horizontal and vertical cup/disc ratios, and cup volume were evaluated. Additionally, cup depth and slope of the temporal ONH were also measured. These ONH parameters were compared between normal subjects and eyes with early POAG and CPACG. Correlation of mean deviation and corrected pattern standard deviation on full threshold 30‐2 perimetry, with measured ONH parameters was carried out amongst the two groups.

Results:  There was a significant difference in disc area (2.38 ± 0.5, 2.77 ± 0.4, 2.62 ± 0.4 mm2, p < 0.01), cup area (0.88 ± 0.6, 1.99 ± 0.7, 1.60 ± 0.7 mm2, p < 0.01), rim area (1.48 ± 0.4, 0.86 ± 0.4, 0.96 ± 0.4 mm2, p < 0.01), VIRA (1.64 ± 0.3, 1.23 ± 0.3, 1.22 ± 0.4 mm2, p < 0.01), rim volume (0.34 ± 0.2, 0.1 ± 0.1, 0.15 ± 0.1 mm3, p < 0.01) and cup/disc ratio (0.36 ± 0.2, 0.69 ± 0.1, 0.63 ± 0.2, p < 0.01) in normal vs POAG vs CPACG eyes respectively. A comparison of ONH parameters between early POAG and early CPACG showed a significant difference in the disc area (2.85 ± 0.3, 2.57 ± 0.4 mm2, p = 0.03), cup area (2 ± 0.5, 1.34 ± 0.5 mm2, p < 0.01), rim area (0.96 ± 0.4, 1.21 ± 0.5 mm2, p = 0.009), rim volume (0.12 ± 0.1, 0.18 ± 0.1 mm3, p < 0.01) and cup/disc ratio (0.67 ± 0.1, 0.53 ± 0.2, p < 0.01). The parameters with the highest area under the receiver operator characteristic (AROC) curves for differentiating normal and early POAG eyes were rim volume, 0.89, VIRA, 0.84, and rim area, 0.76. The AROC values (normal vs early CPACG eyes) were 0.75 for rim volume, 0.72 for VIRA, and 0.66 for rim area.

Conclusion:  OCT may serve as a useful diagnostic modality in distinguishing a normal optic disc from a glaucomatous one, even in the early stages of glaucoma. Rim volume, VIRA and rim area can be used to differentiate normal from early glaucoma (both early POAG and CPACG), and most efficiently early POAG eyes. CPACG eyes have smaller discs, a smaller cup, smaller cup/disc ratio, and a larger rim area when compared with eyes with POAG.
Three portable tonometers, the TGDc‐01, the ICARE and the Tonopen XL, compared with each other and with Goldmann applanation tonometry*
Authors: Van Der Jagt Liane H. , Jansonius Nomdo M.
Published: August 2005

Three portable tonometers, the TGDc‐01, the ICARE and the Tonopen XL, were compared with each other and to Goldmann applanation tonometry in a large group of healthy subjects and patients with ocular hypertension or glaucoma (n = 103). Measurements performed with the ICARE and the Tonopen XL were in good agreement with that of the Goldmann tonometer. Intraocular pressure (IOP) values measured with the TGDc‐01 were significantly lower and showed more variability. The 95% limits of agreement (portable tonometer – Goldmann) were −17 to +10 mmHg for the TGDc‐01, −6 to +7 mmHg for the ICARE and −6 to +8 mmHg for the Tonopen. Corneal thickness could not explain the differences between an IOP measured with the portable tonometers and an IOP measured with the Goldmann tonometer. Patient comfort was slightly higher for ICARE when compared with the Tonopen.
Polyvalent DNA prime and envelope protein boost HIV‐1 vaccine elicits humoral and cellular responses and controls plasma viremia in rhesus macaques following rectal challenge with an R5 SHIV isolate
Authors: Pal Ranajit , Wang Shixia , Kalyanaraman V.S. , Nair B.C. , Whitney Stephen , Keen Timothy , Hocker Lindsey , Hudacik Lauren , Rose Nicolas , Cristillo Anthony , Mboudjeka Innocent , Shen Siyuan , Wu‐Chou Te‐Hui , Montefiori David , Mascola John , Lu Shan , Markham Phillip
Published: August 2005

Abstract:  Immunization of macaques with multivalent DNA encoding gp120 genes from HIV‐1 subtypes A, B, C and E and a gag gene followed by boosting with homologous gp120 proteins elicited strong anti‐gp120 antibodies capable of neutralizing homologous and to a lesser degree heterologous HIV‐1 isolates. Both Env‐ and Gag‐specific cell mediated immune (CMI) responses were detected in the immunized animals. Following rectal challenge with an SHIV isolate encoding HIV‐1Ba‐Lenv, plasma viremia in the infected immunized animals was significantly lower than that observed in the naïve animals. Further, one of six immunized animals was completely protected whereas all six naïve animals were infected. These results demonstrate that a vaccine based on priming with a polyvalent DNA vaccine from multiple HIV‐1 subtypes followed by boosting with homologous Env proteins elicits anti‐HIV‐1 immune responses capable of controlling rectal transmission of SHIVBa‐L.
Structure and Function of the Lowe Syndrome Protein OCRL1
Authors: Lowe Martin
Published: August 2005

Oculocerebrorenal syndrome of Lowe (OCRL) is an X‐linked disorder with the hallmark features of congenital cataracts, mental retardation and Fanconi syndrome of the kidney proximal tubules. OCRL was first described in 1952, and exactly four decades later, the gene responsible was identified and found to encode a protein highly homologous to inositol polyphosphate 5‐phosphatase. This suggested that Lowe syndrome may represent an inborn error of inositol phosphate metabolism, and subsequent studies confirmed that such metabolism is indeed perturbed in Lowe syndrome cells. However, the mechanism by which loss of function of the OCRL1 protein brings about Lowe syndrome remains ill defined. In this review, I will discuss our understanding of OCRL1, including where it is localized, what it interacts with and what its possible functions might be. I will then discuss possible mechanisms by which loss of OCRL1 may bring about cellular defects that manifest themselves in the pathology of Lowe syndrome.
HIV‐1 Gag–RNA Interaction Occurs at a Perinuclear/Centrosomal Site; Analysis by Confocal Microscopy and FRET
Authors: Poole Emma , Strappe Padraig , Mok Hoi‐Ping , Hicks Ray , Lever Andrew M L.
Published: August 2005

The Gag polyprotein is the major structural protein of human immunodeficiency virus‐1 (HIV‐1) constituting the viral core. Between translation on cytoplasmic polysomes and assembly into viral particles at the plasma membrane, it specifically captures the RNA genome of the virus through binding RNA structural motifs (packaging signals –Ψ) in the RNA. RNA is believed to be a structural facilitator of Gag assembly. Using a combined approach of immunofluorescence detection of Gag protein and in situ hybridisation detection of viral genomic RNA, we demonstrate that Gag protein colocalises early after expression with Ψ+ RNA in the perinuclear region and also colocalises with centrioles. Colocalised RNA and protein subsequently traffic through the cytoplasm to the plasma membrane of the cell. Gag expressed from Ψ– RNA diffuses throughout the cell. It is not found at centrioles and shows delayed cytoplasmic colocalisation with the RNA genome. RNA capture through Ψ does not influence binding of Gag to microfilaments. Gag does not bind to tubulin during export. The presence of the packaging signal may coordinate capture of Ψ+ RNA by Gag protein at the centrosome followed by their combined transport to the site of budding. HIV‐1 Ψ thus acts as a subcellular localisation signal as well as a high‐affinity‐binding site for Gag.
Flotillins and the PHB Domain Protein Family: Rafts, Worms and Anaesthetics
Authors: Morrow Isabel C. , Parton Robert G.
Published: August 2005

While our understanding of lipid microdomains has advanced in recent years, many aspects of their formation and dynamics are still unclear. In particular, the molecular determinants that facilitate the partitioning of integral membrane proteins into lipid raft domains are yet to be clarified. This review focuses on a family of raft‐associated integral membrane proteins, termed flotillins, which belongs to a larger class of integral membrane proteins that carry an evolutionarily conserved domain called the prohibitin homology (PHB) domain. A number of studies now suggest that eucaryotic proteins carrying this domain have affinity for lipid raft domains. The PHB domain is carried by a diverse array of proteins including stomatin, podocin, the archetypal PHB protein, prohibitin, lower eucaryotic proteins such as the Dictyostelium discoideum proteins vacuolin A and vacuolin B and the Caenorhabditis elegans proteins unc‐1, unc‐24 and mec‐2. The presence of this domain in some procaryotic proteins suggests that the PHB domain may constitute a primordial lipid recognition motif. Recent work has provided new insights into the trafficking and targeting of flotillin and other PHB domain proteins. While the function of this large family of proteins remains unclear, studies of the C. elegans PHB proteins suggest possible links to a class of volatile anaesthetics raising the possibility that these lipophilic agents could influence lipid raft domains. This review will discuss recent insights into the cell biology of flotillins and the large family of evolutionarily conserved PHB domain proteins.
ApoER2 is Endocytosed by a Clathrin‐Mediated Process Involving the Adaptor Protein Dab2 Independent of its Rafts' Association
Authors: Cuitino Loreto , Matute Ricardo , Retamal Claudio , Bu Guojun , Inestrosa Nibaldo C. , Marzolo María‐Paz
Published: August 2005

The apolipoprotein E receptor 2 (apoER2) is a member of the low‐density lipoprotein receptor family which binds ligands such as reelin, apolipoprotein E and apolipoprotein J/clusterin and has been shown to play roles in neuronal migration during development and in male fertility. The function of apoER2 mainly depends on cellular signaling triggered by ligand binding. Although the receptor is internalized, the mechanism and functional significance of its endocytic trafficking remain unclear. Apolipoprotein E receptor 2 partitions into lipid rafts and interacts with caveolin‐1, a feature that could modulate its endocytic behavior. Recent evidence also suggested that apoER2 might be endocytosed by a pathway independent of clathrin. Here, we show that despite a raft association, apoER2 internalization depends on its cytoplasmic FxNPXY motif that is similar to canonical motifs for clathrin‐mediated endocytosis. This motif mediates receptor binding to the adaptor protein Dab2, which can interact directly with clathrin. Several inhibitory conditions of clathrin‐mediated endocytosis, including expression of the dominant negative forms of eps15 and Dab2, decreased apoER2 internalization. In contrast, treatment with the drug nystatin, which blocks the caveolar/raft internalization pathway, has no effect on the receptor's endocytosis. Neither the transmembrane nor the proline‐rich insert of the cytoplasmic domain, which has been previously reported to exclude the receptor from the clathrin‐mediated pathway, altered apoER2 endocytic activity. These studies indicate that apoER2 internalizes through a clathrin‐mediated pathway and that its association with caveolar and noncaveolar rafts does not determine its endocytosis.
PA700, the regulatory complex of the 26S proteasome, interferes with α‐synuclein assembly
Authors: Ghee Medeva , Melki Ronald , Michot Nadine , Mallet Jacques
Published: August 2005

Parkinson's disease is characterized by the loss of dopaminergic neurons in the nigrostriatal pathway accompanied by the presence of intracellular cytoplasmic inclusions, termed Lewy bodies. Fibrillized α‐synuclein forms the major component of Lewy bodies. We reported a specific interaction between rat α‐synuclein and tat binding protein 1, a subunit of PA700, the regulatory complex of the 26S proteasome. It has been demonstrated that PA700 prevents the aggregation of misfolded, nonubiquinated substrates. In this study, we examine the effect of PA700 on the aggregation of wild‐type and A53T mutant α‐synuclein. PA700 inhibits both wild‐type and A53T α‐synuclein fibril formation as measured by Thioflavin T fluorescence. Using size exclusion chromatography, we present evidence for a stable PA700–α‐synuclein complex. Sedimentation analyses reveal that PA700 sequesters α‐synuclein in an assembly incompetent form. Analysis of the morphology of wild‐type and A53T α‐synuclein aggregates during the course of fibrillization by electron microscopy demonstrate the formation of amyloid‐like fibrils. Secondary structure analyses of wild‐type and A53T α‐synuclein assembled in the presence of PA700 revealed a decrease in the overall amount of assembled α‐synuclein with no significant change in protein conformation. Thus, PA700 acts on α‐synuclein assembly and not on the structure of fibrils. We hypothesize that PA700 sequesters α‐synuclein oligomeric species that are the precursors of the fibrillar form of the protein, thus preventing its assembly into fibrils.
Molecular cloning, expression analysis and functional confirmation of ecdysone receptor and ultraspiracle from the Colorado potato beetle Leptinotarsa decemlineata
Authors: Ogura Takehiko , Minakuchi Chieka , Nakagawa Yoshiaki , Smagghe Guy , Miyagawa Hisashi
Published: August 2005

cDNA cloning of ecdysone receptor (EcR) and ultraspiracle (USP) of the coleopteran Colorado potato beetle Leptinotarsa decemlineata (LdEcR and LdUSP) was conducted. Amino‐acid sequences of the proteins deduced from cDNA sequences showed striking homology to those of other insects, especially the coleopteran yellow mealworm Tenebrio molitor. Northern hybridization analysis showed a 12.4‐kb message for the LdEcR A‐isoform, a 10.5‐kb message for the LdEcR B1‐isoform and a 5.7‐kb message for the LdUSP, in fat body, gut, integument, testis and ovaries. In developmental profile studies, expression of both the LdEcR and LdUSP transcript in integument changed dramatically. In gel mobility shift assays, in vitro translated LdEcR alone bound weakly to the pal1 ecdysone response element, although LdUSP alone did not, and this binding was dramatically enhanced by the addition of LdUSP. LdEcR/LdUSP complex also showed significant binding to an ecdysone agonist, ponasterone A (KD = 2.8 nm), while LdEcR alone showed only weak binding (KD = 73.4 nm), and LdUSP alone did not show any binding. The receptor‐binding affinity of various ecdysone agonists to LdEcR/LdUSP was not correlated to their larvicidal activity to L. decemlineata. From these results, it was suggested that multiple factors including the receptor binding affinity are related to the determination of the larvicidal activity of nonsteroidal ecdysone agonists in L. decemlineata.
Cdc37 maintains cellular viability in Schizosaccharomyces pombe independently of interactions with heat‐shock protein 90
Authors: Turnbull Emma L. , Martin Ina V. , Fantes Peter A.
Published: August 2005

Cdc37 is a molecular chaperone that interacts with a range of clients and co‐chaperones, forming various high molecular mass complexes. Cdc37 sequence homology among species is low. High homology between yeast and metazoan proteins is restricted to the extreme N‐terminal region, which is known to bind clients that are predominantly protein kinases. We show that despite the low homology, both Saccharomyces cerevisiae and human Cdc37 are able to substitute for the Schizosaccharomyces pombe protein in a strain deleted for the endogenous cdc37 gene. Expression of a construct consisting of only the N‐terminal domain of S. pombe Cdc37, lacking the postulated heat‐shock protein (Hsp) 90‐binding and homodimerization domains, can also sustain cellular viability, indicating that Cdc37 dimerization and interactions with the cochaperone Hsp90 may not be essential for Cdc37 function in S. pombe. Biochemical investigations showed that a small proportion of total cellular Cdc37 occurs in a high molecular mass complex that also contains Hsp90. These data indicate that the N‐terminal domain of Cdc37 carries out essential functions independently of the Hsp90‐binding domain and dimerization of the chaperone itself.
A novel thermostable hemoglobin from the actinobacterium Thermobifida fusca
Authors: Bonamore Alessandra , Ilari Andrea , Giangiacomo Laura , Bellelli Andrea , Morea Veronica , Boffi Alberto
Published: August 2005

The gene coding for a hemoglobin‐like protein (Tf‐trHb) has been identified in the thermophilic actinobacterium Thermobifida fusca and cloned in Escherichia coli for overexpression. The crystal structure of the ferric, acetate‐bound derivative, was obtained at 2.48 Å resolution. The three‐dimensional structure of Tf‐trHb is similar to structures reported for the truncated hemoglobins from Mycobacterium tuberculosis and Bacillus subtilis in its central domain. The complete lack of diffraction patterns relative to the N‐ and C‐terminal segments indicates that these are unstructured polypeptides chains, consistent with their facile cleavage in solution. The absence of internal cavities and the presence of two water molecules between the bound acetate ion and the protein surface suggest that the mode of ligand entry is similar to that of typical hemoglobins. The protein is characterized by higher thermostability than the similar mesophilic truncated hemoglobin from B. subtilis, as demonstrated by far‐UV CD melting experiments on the cyano‐met derivatives. The ligand‐binding properties of Tf‐trHb, analyzed in stopped flow experiments, demonstrate that Tf‐trHb is capable of efficient O2 binding and release between 55 and 60 °C, the optimal growth temperature for Thermobifida fusca.
Levels of mTOR and its downstream targets 4E‐BP1, eEF2, and eEF2 kinase in relationships with tau in Alzheimer's disease brain
Authors: Li Xu , Alafuzoff Irina , Soininen Hilkka , Winblad Bengt , Pei Jin‐Jing
Published: August 2005

The pathogenesis of formation of neurofibrillary tangles (NFTs) in Alzheimer's disease (AD) brains is unknown. One of the possibilities might be that translation of tau mRNA is aberrantly regulated in AD brains. In the current study, levels of various translation control elements including total and phosphorylated (p) forms of mammalian target of rapamycin (mTOR), eukaryotic initiation factor 4E binding protein 1 (4E‐BP1), eukaryotic elongation factor 2 (eEF2), and eEF2 kinase were investigated in relationship with tau in homogenates of the medial temporal cortex from 20 AD and 10 control brains. We found that levels of p‐mTOR (Ser2481), and p‐4E‐BP1 (Thr70 and Ser65) dramatically increase in AD, and are positively significantly correlated with total tau and p‐tau. Levels of p‐eEF2K were significantly increased, and total eEF2 significantly decreased in AD, when compared to controls. The changes of p‐mTOR (2481), p‐4E‐BP1, and p‐eEF2 were immunohistochemically confirmed to be in neurons of AD brains. This suggested that there are obvious abnormalities of elements related with translation control in AD brain and their aberrant changes may up‐regulate the translation of tau mRNA, contributing to hyperphosphorylated tau accumulation in NFT‐bearing neurons.
Recombinant derivatives of the human high‐mobility group protein HMGB2 mediate efficient nonviral gene delivery
Authors: Sloots Arjen , Wels Winfried S.
Published: August 2005

Certain natural peptides and proteins of mammalian origin are able to bind and condense plasmid DNA, a prerequisite for the formation of transfection‐competent complexes that facilitate nonviral gene delivery. Here we have generated recombinant derivatives of the human high‐mobility group (HMG) protein HMGB2 and investigated their potential as novel protein‐based transfection reagents. A truncated form of HMGB2 encompassing amino acids 1–186 of the molecule was expressed in Escherichia coli at high yield. This HMGB2186 protein purified from bacterial lysates was able to condense plasmid DNA in a concentration‐dependent manner, and mediated gene delivery into different established tumor cell lines more efficiently than poly(l‐lysine). By attaching, via gene fusion, additional functional domains such as the HIV‐1 TAT protein transduction domain (TATPTD‐HMGB2186), the nuclear localization sequence of the simian virus 40 (SV40) large T‐antigen (SV40NLS‐HMGB2186), or the importin‐β‐binding domain (IBB) of human importin‐α (IBB‐HMGB2186), chimeric fusion proteins were produced which displayed markedly improved transfection efficiency. Addition of chloroquine strongly enhanced gene transfer by all four HMGB2186 derivatives studied, indicating cellular uptake of protein–DNA complexes via endocytosis. The IBB‐HMGB2186 molecule in the presence of the endosomolytic reagent was the most effective. Our results show that recombinant derivatives of human HMGB2 facilitate efficient nonviral gene delivery and may become useful reagents for applications in gene therapy.
Benzamide and 4‐amino 1,8 naphthalimide treatment inhibit telomerase activity by down‐regulating the expression of telomerase associated protein and inhibiting the poly(ADP‐ribosyl)ation of telomerase reverse transcriptase in cultured cells
Authors: Ghosh Utpal , Bhattacharyya Nitai P.
Published: August 2005

To test the role of poly(ADP‐ribose) polymerase on the telomerase activity, we determined the telomerase activity in leukemic cells K562 treated with benzamide and 4‐amino 1,8 naphthalimide (NAP), the inhibitors of PARP. We observed that both the agents inhibited telomerase activity in a dose‐dependent manner. The doses of benzamide and NAP that inhibited telomerase activity to 50% of untreated control cells were 10.7 ± 0.6 mm and 200 ± 7 µm, respectively. Benzamide treatment (10 mm) inhibited telomerase activity in a time‐dependent manner. We also tested the ability of benzamide to inhibit the telomerase activity in Chinese hamster V79 cells and observed similar inhibition of the telomerase activity. Expression of telomerase reverse transcriptase (TERT) and telomerase RNA component, detected by RT‐PCR, remained unaltered by treatment with benzamide or NAP. On the contrary, the expression of telomerase associated protein (TEP1/TP1), as detected by RT‐PCR and western blot analysis, was reduced by both the agents. Further, in K562 cells, immunoprecipitation with the anti‐TERT IgG and probed anti‐poly (ADP‐ribose) IgG revealed that TERT was poly(ADP‐ribosyl)ated in the physiological condition of cell growth and such poly(ADP‐ribosyl)ation was inhibited by benzamide treatment. Decrease in TEP1/TP1 expression and poly(ADP‐ribosyl)ation of TERT were correlated with the inhibition of PARP activity by benzamide, indicating that PARP had a role in telomerase activity through poly(ADP‐ribosyl)ation of TERT and down‐regulation of TEP1/TP1.
Structural identification of ladderane and other membrane lipids of planctomycetes capable of anaerobic ammonium oxidation (anammox)
Authors: Sinninghe Damsté Jaap S. , Rijpstra W. Irene C. , Geenevasen Jan A. J. , Strous Marc , Jetten Mike S. M
Published: August 2005

The membrane lipid composition of planctomycetes capable of the anaerobic oxidation of ammonium (anammox), i.e. Candidatus‘Brocadia anammoxidans’ and Candidatus‘Kuenenia stuttgartiensis’, was shown to be composed mainly of so‐called ladderane lipids. These lipids are comprised of three to five linearly concatenated cyclobutane moieties with cis ring junctions, which occurred as fatty acids, fatty alcohols, alkyl glycerol monoethers, dialkyl glycerol diethers and mixed glycerol ether/esters. The highly strained ladderane moieties were thermally unstable, which resulted in breakdown during their analysis with GC. This was shown by isolation of a thermal product of these ladderanes and subsequent analysis with two‐dimensional NMR techniques. Comprehensive MS and relative retention time data for all the encountered ladderane membrane lipids is reported, allowing the identification of ladderanes in other bacterial cultures and in the environment. The occurrence of ladderane lipids seems to be limited to the specific phylogenetic clade within the Planctomycetales able to perform anammox. This was consistent with their proposed biochemical function, namely as predominant membrane lipids of the so‐called anammoxosome, the specific organelle where anammox catabolism takes place in the cell.
Retention of Inorganic Nitrogen by Epiphytic Bryophytes in a Tropical Montane Forest1
Authors: Clark Kenneth L. , Nadkarni Nalini M. , Gholz Henry L.
Published: August 2005

We developed and evaluated a model of the canopy of a tropical montane forest at Monteverde, Costa Rica, to estimate inorganic nitrogen (N) retention by epiphytes from atmospheric deposition. We first estimated net retention of inorganic N by samples of epiphytic bryophytes, epiphyte assemblages, vascular epiphyte foliage, and host tree foliage that we exposed to cloud water and precipitation solutions. Results were then scaled up to the ecosystem level using a multilayered model of the canopy derived from measurements of forest structure and epiphyte mass. The model was driven with hourly meteorological and event‐based atmospheric deposition data, and model predictions were evaluated against measurements of throughfall collected at the site. Model predictions were similar to field measurements for both event‐based and annual hydrologic and inorganic N fluxes in throughfall. Simulation of individual events indicated that epiphytic bryophytes and epiphyte assemblages retained 33–67 percent of the inorganic N deposited in cloud water and precipitation. On an annual basis, the model predicted that epiphytic components retained 3.4 kg N ha/yr, equivalent to 50 percent of the inorganic N in atmospheric deposition (6.8 kg N ha/yr). Our results indicate that epiphytic bryophytes play a major role in N retention and cycling in this canopy by transforming highly mobile inorganic N (ca. 50% of atmospheric deposition is NO−3) to less mobile (exchangeable NH+4) and recalcitrant forms in biomass and remaining litter and humus.
Disturbance Effects on the Seed Bank of Mexican Cloud Forest Fragments1
Authors: Alvarez‐Aquino C. , Williams‐Linera G. , Newton A. C.
Published: August 2005

The density and floristic composition of the soil seed bank was assessed in six cloud forest fragments with different levels of human disturbance in central Veracruz, Mexico. A total of 8416 seeds germinated in 60 soil samples, at 5‐cm depth, corresponding to 107 species, 85 genera, and 48 families. Significant differences were found among study sites in seed densities with values ranging from 873 to 3632/m2. Tree species contributed 20 percent of the total soil seed bank in four sites and herbs accounted for the majority of the species in each site. Among tree species, Trema micrantha displayed the highest seed density, accounting for 84 percent of the germinated seeds. In general, the tree species composition of the soil seed bank did not closely reflect the composition of the tree community. Results suggest that disturbance produced by human activities (trail use, selective cutting of trees, livestock) may influence the size and composition of the soil seed bank in forest fragments. Sites where human activity has been reduced showed the highest proportion of dormant seeds.
Vegetative Phenology and Growth of a Facultatively Deciduous Bamboo in a Monsoonal Climate1
Authors: Franklin Donald C.
Published: August 2005

Canopy closure, leaf flush, and ramet recruitment in Bambusa arnhemica, a semelparous, clumping bamboo from the Australian monsoonal tropics, were monitored monthly for 2.5 years at three sites along a flood gradient. Bambusa arnhemica was facultatively deciduous, remaining evergreen at a downslope riparian site but suffering total loss of canopy on a hillside for up to 4 mo during the dry season. Leaf flush was flexible, occurring after as little as 25 mm of rain at the onset of wet season, in response to unusual dry season storms, and apparently also in response to fire independent of rainfall. New culms emerged soon after leaf flush early in the wet season. Culm growth took place during the middle and late wet season, with peak elongation rates of 15–30 cm/day. Some growth continued into the dry season, mostly on branches and leaves of new culms at riparian sites. Not all culms completed elongation before the onset of the dry season, and those that did not were permanently stunted. The demands of culm elongation may limit the occurrence of bamboo in wet‐dry climates to areas with predictable and sustained wet season rainfall, but the flexibility of branching and leaf processes facilitates coping with, and permits exploitation of less predictable pre‐ and postmonsoonal rains. The bamboo growth form and phenological patterns differ markedly from those of dicotyledonous trees and shrubs.
Pollination Biology of the Exotic Rattleweed Crotalaria retusa L. (Fabaceae) in NE Brazil1
Authors: Jacobi Claudia M. , Ramalho Mauro , Silva Maise
Published: August 2005

The rattleweed Crotalaria retusa was introduced in Brazil from Africa, and combines a series of characters that have ensured its establishment in NE Brazil. We focused on its reproductive biology and pollinator behavior to explain its reproductive success. We performed manual pollination and germination experiments, and monitored the behavior of C. retusa's main pollinators in monospecific plots, and in mixed plots where C. retusa occurred together with two congeners, Crotalaria pallida and Crotalaria lanceolata. Crotalaria retusa is self‐compatible and capable of automatic selfing. Inbreeding depression was expressed at the level of percent seed germination, but not seed set. Few insects visited the inflorescences. Legitimate pollinators were two large carpenter bees, Xylocopa frontalis and Xylocopa grisescens which, together, accounted for more than 90 percent of the visits. The former foraged on C. retusa exclusively and has low pollen spread potential. The latter flew longer distances between plants and visited fewer flowers per inflorescence, potentially increasing the extent of pollen carryover, but at the risk of increasing heterospecific pollen transfer, because it visits other Crotalaria species during the same foraging bout. The different foraging strategies, allied to morphological disadvantages represented by pollen overlap on X. grisescens' body, may partially explain the much lower seed germination observed in C. pallida and C. lanceolata. These results are consistent with the hypothesis that a reduction in flower constancy may significantly depress viable seed set by increasing the chances of self‐pollination.
Equal and Opposite Effects of Floral Offer and Spatial Distribution on Fruit Production and Predispersal Seed Predation in Xanthosoma daguense (Araceae)1
Authors: García‐Robledo Carlos , Kattan Gustavo , Murcia Carolina , Quintero‐Marín Paulina
Published: August 2005

Inflorescences of the terrestrial aroid Xanthosoma daguense in the Andes of Colombia are visited by Dinastinae and Nitidulidae beetles. Plants produce one inflorescence at a time, which is pollinated during the first night of opening. Dynastine beetles act as pollinators, whereas Nitidulids lay eggs in the inflorescence and the larvae damage the seeds. We explored the effects of floral offer and distance among inflorescences on the number of pollinator visits, fruit production, and predispersal seed predation. Number of Dynastine visits per inflorescence tended to increase with increasing distances among inflorescences, but fruit predation increased when inflorescences were more clumped. Both pollinator visitation rates and predispersal seed predation were low at high floral offer. Fruit set increased when inflorescences were visited by two or more Dynastines, but the proportion of fruits damaged by Nitidulid larvae was equivalent to the increase in fruit production due to more Dinastine visits. The net result was a similar number of undamaged fruits in all infructescences produced, independent of the number of Dinastine visits. Our results revealed that both pollinators and predators responded to the number of available inflorescences and their spatial distribution, but they had opposing effects on the infructescences. Thus, our study suggests that the interaction of two ecological processes, pollination and predispersal seed predation, may cancel each other's effects under natural conditions.
Limited Fruit Production in Hancornia speciosa (Apocynaceae) and Pollination by Nocturnal and Diurnal Insects1
Authors: Darrault Reisla O. , Schlindwein Clemens
Published: August 2005

Frequency and efficiency of pollinator visits strongly influence the reproductive success of self‐incompatible plants. We investigated the breeding and pollination systems of Hancornia speciosa, a small tree that produces fleshy berries used in the Brazilian fruit industry. Observation and experiments were carried out in Northeastern Brazil. Thirty‐three species of the visitor were recorded. Hawkmoths (Sphingidae), bees (Euglossini and Centridini), and butterflies (Nymphalidae and Hesperiidae) with long mouth parts were effective pollinators of H. speciosa. Access to nectar, the only reward for flower visitors, is determined by corolla tube length. Nylon threads of various diameters and dried mouth parts from a number of flower visitors were used in experiments to simulate flower visits. The number of pollen grains removed during such simulated visits showed no significant difference. Although xenogamic, H. speciosa presented a low pollen/ovule ratio (77). This might be related to the high efficiency of its pollination mechanism. Flowers of H. speciosa had 76 ovules on average. Seed set varied from 1 to 25, indicating that individual flowers received different amounts of outcross‐pollen. Fruit production of hand cross‐pollinated flowers increased by 90 percent when compared to natural pollination, suggesting pollinator limitation of H. speciosa.
Predispersal Seed Predation by Insects vs. Vertebrates in Six Dipterocarp Species in Sarawak, Malaysia1
Authors: Nakagawa Michiko , Takeuchi Yayoi , Kenta Tanaka , Nakashizuka Tohru
Published: August 2005

We investigated the predispersal survivorship of seeds of six dipterocarp species (Dipterocarpus globosus, D. tempehes, Dryobalanops aromatica, D. lanceolata, Shorea beccariana, and S. pilosa) during 2001–2002, when a general flowering occurred in Lambir Hills National Park, Sarawak, Malaysia. More immature seeds dropped during the first month in Dryobalanops and Shorea spp. than in Dipterocarpus spp. Insects attacked the seeds of all species during all developmental stages through to maturity, although temporal patterns varied among the dipterocarps. In contrast, arboreal vertebrates only occasionally ate seeds, and produced less damage than insects. In four species, insects damaged a significantly higher percentage of seeds than did vertebrates. Direct observations of seed survival patterns and bagging experiments using two sizes of mesh (cloth and wire) in the canopy of Dryobalanops aromatica identified insects as the principal seed predators during both the last phase, and overall. These results document the relative importance of insects as predispersal seed predators in these dipterocarp species.