bluuebunny/crossref_metadata_2025 huggingface dataset:
Fine‐scale population structure and riverscape genetics of brook trout (Salvelinus fontinalis) distributed continuously along headwater channel networks
Authors: KANNO YOICHIRO , VOKOUN JASON C. , LETCHER BENJAMIN H.
Published: August 2011

Linear and heterogeneous habitat makes headwater stream networks an ideal ecosystem in which to test the influence of environmental factors on spatial genetic patterns of obligatory aquatic species. We investigated fine‐scale population structure and influence of stream habitat on individual‐level genetic differentiation in brook trout (Salvelinus fontinalis) by genotyping eight microsatellite loci in 740 individuals in two headwater channel networks (7.7 and 4.4 km) in Connecticut, USA. A weak but statistically significant isolation‐by‐distance pattern was common in both sites. In the field, many tagged individuals were recaptured in the same 50‐m reaches within a single field season (summer to fall). One study site was characterized with a hierarchical population structure, where seasonal barriers (natural falls of 1.5–2.5 m in height during summer base‐flow condition) greatly reduced gene flow and perceptible spatial patterns emerged because of the presence of tributaries, each with a group of genetically distinguishable individuals. Genetic differentiation increased when pairs of individuals were separated by high stream gradient (steep channel slope) or warm stream temperature in this site, although the evidence of their influence was equivocal. In a second site, evidence for genetic clusters was weak at best, but genetic differentiation between individuals was positively correlated with number of tributary confluences. We concluded that the population‐level movement of brook trout was limited in the study headwater stream networks, resulting in the fine‐scale population structure (genetic clusters and clines) even at distances of a few kilometres, and gene flow was mitigated by ‘riverscape’ variables, particularly by physical barriers, waterway distance (i.e. isolation‐by‐distance) and the presence of tributaries.
Effects of Pleistocene climatic fluctuations on the phylogeographic and demographic histories of Pacific herring (Clupea pallasii)
Authors: LIU JIN‐XIAN , TATARENKOV ANDREY , BEACHAM TERRY D. , GORBACHEV VICTOR , WILDES SHARON , AVISE JOHN C.
Published: August 2011

We gathered mitochondrial DNA sequences (557 bp from the control region in 935 specimens and 668 bp of the cytochrome b gene in 139 specimens) of Pacific herring collected from 20 nearshore localities spanning the species’ extensive range along the North Pacific coastlines of Asia and North America. Haplotype diversity and nucleotide diversity were high, and three major phylogeographic lineages (sequence divergences ca. 1.5%) were detected. Using a variety of phylogenetic methods, coalescent reasoning, and molecular dating interpreted in conjunction with paleoclimatic and physiographic evidence, we infer that the genetic make‐up of extant populations of C. pallasii was shaped by Pleistocene environmental impacts on the historical demography of this species. A deep genealogical split that cleanly distinguishes populations in the western vs. eastern North Pacific probably originated as a vicariant separation associated with a glacial cycle that drove the species southward and isolated two ancestral populations in Asia and North America. Another deep genealogical split may have involved either a vicariant isolation of a third herring lineage (perhaps originally in the Gulf of California) or it may have resulted simply from the long coalescent times that are possible in large populations. Coalescent analyses showed that all the three evolutionary lineages of C. pallasii experienced major expansions in their most recent histories after having remained more stable in the preceding periods. Independent of the molecular calibration chosen, populations of C. pallasii appear to have remained stable or grown throughout the periods that covered at least two major glaciations, and probably more.
The copper regulon of the human fungal pathogen Cryptococcus neoformans H99
Authors: Ding Chen , Yin Jun , Tovar Edgar Mauricio Medina , Fitzpatrick David A. , Higgins Desmond G. , Thiele Dennis J.
Published: August 2011

Cryptococcus neoformans is a human fungal pathogen that is the causative agent of cryptococcosis and fatal meningitis in immuno‐compromised hosts. Recent studies suggest that copper (Cu) acquisition plays an important role in C. neoformans virulence, as mutants that lack Cuf1, which activates the Ctr4 high affinity Cu importer, are hypo‐virulent in mouse models. To understand the constellation of Cu‐responsive genes in C. neoformans and how their expression might contribute to virulence, we determined the transcript profile of C. neoformans in response to elevated Cu or Cu deficiency. We identified two metallothionein genes (CMT1 and CMT2), encoding cysteine‐rich Cu binding and detoxifying proteins, whose expression is dramatically elevated in response to excess Cu. We identified a new C. neoformans Cu transporter, CnCtr1, that is induced by Cu deficiency and is distinct from CnCtr4 and which shows significant phylogenetic relationship to Ctr1 from other fungi. Surprisingly, in contrast to other fungi, we found that induction of both CnCTR1 and CnCTR4 expression under Cu limitation, and CMT1 and CMT2 in response to Cu excess, are dependent on the CnCuf1 Cu metalloregulatory transcription factor. These studies set the stage for the evaluation of the specific Cuf1 target genes required for virulence in C. neoformans.
The Leishmania nicotinamidase is essential for NAD+ production and parasite proliferation
Authors: Gazanion E. , Garcia D. , Silvestre R. , Gérard C. , Guichou J. F. , Labesse G. , Seveno M. , Cordeiro‐Da‐Silva A. , Ouaissi A. , Sereno D. , Vergnes B.
Published: August 2011

NAD+ is a central cofactor that plays important roles in cellular metabolism and energy production in all living cells. Genomics‐based reconstruction of NAD+ metabolism revealed that Leishmania protozoan parasites are NAD+ auxotrophs. Consequently, these parasites require assimilating NAD+ precursors (nicotinamide, nicotinic acid, nicotinamide riboside) from their host environment to synthesize NAD+ by a salvage pathway. Nicotinamidase is a key enzyme of this salvage pathway that catalyses conversion of nicotinamide (NAm) to nicotinic acid (Na), and that is absent in higher eukaryotes. We present here the biochemical and functional characterizations of the Leishmania infantum nicotinamidase (LiPNC1). Generation of Lipnc1 null mutants leads to a decrease in NAD+ content, associated with a metabolic shutdown‐like phenotype with an extensive lag phase of growth. Both phenotypes could be rescued by an add‐back construct or by addition of exogenous Na. In addition, Lipnc1 null mutants were unable to establish a sustained infection in a murine experimental model. Altogether, these results illustrate that NAD+ homeostasis is a fundamental component of Leishmania biology and virulence, and that NAm constitutes its main NAD+ source in the mammalian host. The crystal structure of LiPNC1 we solved allows now the design of rational inhibitors against this new promising therapeutic target.
Morphological, molecular and biological evidence reveal two cryptic species inMecinus janthinusGermar (Coleoptera, Curculionidae), a successful biological control agent of Dalmatian toadflax,Linaria dalmatica(Lamiales, Plantaginaceae)
Authors: TOŠEVSKI IVO , CALDARA ROBERTO , JOVIĆ JELENA , HERNÁNDEZ‐VERA GERARDO , BAVIERA COSIMO , GASSMANN ANDRE , EMERSON BRENT C.
Published: August 2011

A combined morphological, molecular and biological study shows that the weevil species presently namedMecinus janthinusis actually composed of two different cryptic species:M. janthinusGermar, 1821 andM. janthiniformisToševski & Caldarasp.n.These species are morphologically distinguishable from each other by a few very subtle morphological characters. On the contrary, they are more readily distinguishable by both molecular and biological characters. A molecular assessment based on the mitochondrial DNA cytochrome oxidase subunit II gene revealed fixed differences between the two species with p‐distances between samples of both species ranging from 1.3 to 2.4%. In addition to this, the larvae of the two species are found to develop on different species within the genusLinaria(Plantaginaceae):M. janthinusis associated with yellow toadflax (L. vulgaris) andM. janthiniformiswith broomleaf toadflax (L. genistifolia) and Dalmatian toadflax (L. dalmatica). Molecular and host use records further suggest the occurrence of a third species associated withL. vulgariswithinM. janthinus,sampled from north Switzerland, central Hungary and east Serbia. The significance of these new findings is of particular importance because species of theM. janthinusgroup are used, or are potential candidates, for the biological control of invasive toadflaxes in North America.
Use of a microsatellite‐based pedigree in estimation of heritabilities for economic traits in Australian blue mussel, Mytilus galloprovincialis
Authors: Nguyen T.T.T. , Hayes B.J. , Guthridge K. , Ab Rahim E.S. , Ingram B.A.
Published: August 2011

This study aimed to estimate the heritabilities of three economically important traits (total weight, shell shape and meat yield) in Australian blue mussels. The estimates were derived using a pedigree reconstructed from a suite of both published and newly developed microsatellite markers. A total of 135 microsatellite loci were tested, of which 10 loci produced consistent PCR amplification and reliable results across all samples (74 full‐sibling families including 74 pairs of parents and 2536 offspring). Lack of polymorphism at the non‐repetitive region of the adhesive protein gene confirmed that the broodstock were derived from a single species. A total of 1538 progenies (62.5%) could be assigned to single parent pairs, and the remainder were assigned to two families or more, so were discarded from further analysis. Heritabilities for total weight, shell shape and meat yield were low (0.051 ± 0.027, 0.085 ± 0.038 and 0.049 ± 0.028, respectively) but reflected large environmental variation rather than limited genetic variation, suggesting a family‐based breeding programme could improve these traits. The genetic correlation between weight and meat yield, expressed as percentage of total mussel which was not shell, was negative, while the genetic correlation between meat yield and shell shape was weakly positive.
Training‐induced modifications of circadian rhythmicity of peroxidative parameters in horses
Authors: Piccione G. , Giannetto C. , Marafioti S. , Faggio C. , Alberghina D. , Fazio F.
Published: August 2011

The aim of this study was to evaluate the daily rhythms of peroxidative parameters in untrained and trained horses. Blood samples were collected every 4 h for a 48‐h period for the determination of reactive oxygen metabolites test (d‐ROMs), antioxidant barrier (Oxy‐ads), thiol antioxidant barrier (SHp) and lipid peroxidation (LPO). Two‐way anova showed a significant effect of time of day on all parameters studied, except on LPO. Higher values of Oxy‐ads and SHp were observed in trained horses during both days of monitoring (p < 0.01). All studied parameters, except for LPO, showed robust daily rhythms. Their acrophases occurred during the day in untrained horses and in the evening in trained horses. Our results showed that training increases antioxidative capacity and demonstrated that the daily rhythms of antioxidative parameters can be modified by training.
Xanthophylls are key constituents of semi‐synthetic diets for continuous breeding of Pieris brassicae without food plant
Authors: Kayser H.
Published: August 2011

Semi‐synthetic or fully artificial diets are well established in culturing laboratory insects on a large scale. In Pieris brassicae L. (Lepidoptera: Pieridae), a published semi‐synthetic diet supplemented with sinigrin, a chemical label of cruciferous plants, is well accepted by the larvae but the adults fail to produce offspring; continuous breeding, therefore, requires the addition of cabbage powder to the diet. We set out to identify essential substances to eliminate the need for cabbage in our long‐term mass culture. The studies revealed that the dietary difference, which becomes most evident at the adult stage only, is because of a severe lack of carotenoids in the cabbage‐free version. This was uncovered in larvae, fed cabbage‐supplemented diet, that respond to blue light of sufficient intensity by high cuticle melanization on pupation; larvae fed the carotenoid‐deficient sinigrin‐supplemented diet fail to respond in this way. Males were found to be more sensitive than females to blue light in this respect. The essential substance mediating this photo response was found to be lutein and/or zeaxanthin, two abundant xanthophylls of green leaves. β‐Carotene was only marginally active. These xanthophylls are known to serve as precursors to the synthesis of 3‐hydroxyretinal, the exclusive visual chromophore of lepidopteran insects; retinal, derived from β‐carotene, is not (substantially) used by these insects. In conclusion, the absence of flying and mating activity in the adults from the sinigrin diet may indicate visual deficiency owing to a lack of a specific structural class of carotenoids in the larval food. Our results enabled us to formulate a semi‐synthetic diet that allows continuous mass rearing of P. brassicae without cabbage at any stage including oviposition. In addition to the key constituents sinigrin and xanthophylls, this superior diet includes tryptophan, as methyl ester, and α‐tocopherol.
Renal carcinoma with (6;11)(p21;q12) translocation: Report of an adult case
Authors: Ishihara Akira , Yamashita Yasuhiro , Takamori Hiroki , Kuroda Naoto
Published: August 2011

An extremely rare adult example of renal carcinoma with t(6;11)(p21;q12 or q13) is presented here. The tumor of a 45‐year‐old Japanese male, excised under the diagnosis of renal cell carcinoma, was a well circumscribed 7 cm mass with light brown sectioned surfaces. Histologically, it was composed of a major population of large polygonal epithelioid cells in a nested alveolar growth and a subpopulation of smaller cells clustering around hyaline basement membrane material. The former cells possessed ample, clear to eosinophilic granular cytoplasm with well‐defined cell borders and the latter was frequently accompanied by psammomatous calcification. These tumor cells exhibited immunoreactivity for melanoma markers, transcription factor EB and cathepsin K, but were not reactive for epithelial markers and transcription factor E3. While pulmonary metastatic foci that were noted preoperatively progressed rapidly following interferon‐based therapy, subsequent sunitinib malate yielded a partial response and stabilized the lung metastasis for 6 months after surgery. We could trace 20 cases of 6p21 translocation renal carcinoma, among which only four were in individuals older than 40 years. Description of a new case like this is important since little is known about the prognosis and treatment of adult patients with this condition.
Separation of fluorescence‐labelled terminal restriction fragment DNA on a two‐dimensional gel (T‐RFs‐2D) – an efficient approach for microbial consortium characterization
Authors: Wang Shanquan , He Jianzhong
Published: August 2011

Fingerprinting techniques provide access to understanding the ecology of uncultured microbial consortia. However, the application of current techniques such as terminal restriction fragment length polymorphism (T‐RFLP) and denaturing gradient gel electrophoresis (DGGE) has been hindered due to their limitations in characterizing complex microbial communities. This is due to that different populations possibly share the same terminal restriction fragments (T‐RFs) and DNA fragments may co‐migrate on DGGE gels. To overcome these limitations, a new approach was developed to separate terminal restriction fragments (T‐RFs) of 16S rRNA genes on a two‐dimensional gel (T‐RFs‐2D). T‐RFs‐2D involves restriction digestion of terminal fluorescence‐labelled PCR amplified 16S rRNA gene products and their high‐resolution separation via a two‐dimensional (2D) gel electrophoresis based on the T‐RF fragment size (1st D) and its sequence composition on the denaturing gradient gel (2nd D). The sequence information of interested T‐RFs on 2D gels can be obtained through serial poly(A) tailing reaction, PCR amplification and subsequent DNA sequencing. By employing the T‐RFs‐2D method, bacteria with MspI digested T‐RF size of 436 (±1) bp and 514 (±1) bp were identified to be a Lysobacter sp. and a Dehalococcoides sp. in a polychlorinated biphenyl (PCB) dechlorinating culture. With the high resolution of 2D separation, T‐RFs‐2D separated 63 DNA fragments in a complex river‐sediment microbial community, while traditional DGGE detected only 41 DNA fragments in the same sample. In all, T‐RFs‐2D has its advantage in obtaining sequence information of interested T‐RFs and also in characterization of complex microbial communities.
Transcriptional regulation of α‐cell differentiation
Authors: Bramswig N. C. , Kaestner K. H.
Published: August 2011

The development of the endocrine pancreas and the differentiation of its five cell types, α, β, δ, ε and pancreatic polypeptide (PP) cells, are a highly complex and tightly regulated process. Proper differentiation and function of α‐ and β‐cells are critical for blood glucose homeostasis. These processes are governed by multiple transcription factors and other signalling systems, and its dysregulation results in diabetes. The differentiation of α‐cells and the maintenance of α‐cell function can be influenced at several stages during development and in the maturing islet. Many transcription factors, such as neurogenin 3 (Ngn3), pancreatic duodenal homeobox 1 (Pdx1) and regulatory factor x6 (Rfx6), play a crucial role in the determination of the endocrine cell fate, while other transcription factors, such as aristaless‐related homeobox (Arx) and forkhead box A2 (Foxa2), are implicated in the initial or terminal differentiation of α‐cells. In vivo and in vitro studies have shown that preproglucagon transcription, and therefore the maintenance of α‐cell function, is regulated by several factors, including forkhead box A1 (Foxa1), paired box 6 (Pax6), brain4 (Brn4) and islet‐1 (Isl‐1). Detailed information about the regulation of normal and abnormal α‐cell differentiation gives insight into the pathogenesis of diabetes, identifies further targets for diabetes treatment and provides clues for the reprogramming of α‐ to β‐cells for replacement therapy.
In vivo conversion of adult α‐cells into β‐like cells: a new research avenue in the context of type 1 diabetes
Authors: Courtney M. , Pfeifer A. , Al‐Hasani K. , Gjernes E. , Vieira A. , Ben‐Othman N. , Collombat P.
Published: August 2011

Type 1 diabetes is caused by the loss of insulin‐producing β‐cells as a result of an autoimmune condition. Despite current therapeutic approaches aimed at restoring the insulin supply, complications caused by variations in glycaemia may still arise with age. There is therefore mounting interest in the establishment of alternative therapies. Most current approaches consist in designing rational protocols for in vitro or in vivo cell differentiation/reprogramming from a number of cell sources, including stem, progenitor or differentiated cells. Towards this ultimate goal, it is clear that we need to gain further insight into the interplay between signalling events and transcriptional networks that act in concert throughout pancreatic morphogenesis. This short review will therefore focus on the main events underlying pancreatic development with particular emphasis on the genetic determinants implicated, as well as on the relatively new concept of endocrine cell reprogramming, that is the conversion of pancreatic α‐cells into cells displaying a β‐cell phenotype.
Longevity of human islet α‐ and β‐cells
Authors: Cnop M. , Igoillo‐Esteve M. , Hughes S. J. , Walker J. N. , Cnop I. , Clark A.
Published: August 2011

Pancreatic islet cell regeneration is considered to be important in the onset and progression of diabetes and as a potential cell therapy. Current hypotheses, largely based on rodent studies, indicate continuous turnover and plasticity of α‐ and β‐cells in adults; cell populations in rodents respond to increased secretory demand in obesity (30‐fold β‐cell increase) and pregnancy. Turnover and plasticity of islet cells decrease in mice within >1 year. In man, morphometric observations on postmortem pancreas have indicated that the cellular expansion is much smaller than the increased insulin secretion that accompanies obesity. Longevity of β‐cells in humans >20–30 years has been shown by 14C measurements and bromo‐deoxyuridine (BrdU) incorporation and there is an age‐related decline in the expression of proteins associated with cell division and regeneration including cyclin D3 and PDX‐1. Quantitative estimation and mathematical modelling of the longevity marker, cellular lipofuscin body content, in islets of subjects aged 1–84 years indicated an age‐related increase and that 97% of the human β‐cell population was established by the age of 20. New data show that human α‐cell lipofuscin content is less than that seen in β‐cells, but the age‐related accumulation is similar; lipofuscin‐positive (aged) cells form ≥95% of the population after 20 years. Increased turnover of cellular organelles such as mitochondria and endoplasmic reticulum could contribute to lipofuscin accumulation with age in long‐lived cells. Induction of regeneration of human islet cells will require understanding of the mechanisms associated with age‐related senescence.
Novel insight into glucagon receptor action: lessons from knockout and transgenic mouse models
Authors: Vuguin P. M. , Charron M. J.
Published: August 2011

Using knockout and transgenic technology, genetically modified animal models allowed us to understand the role of glucagon signalling in metabolism. Mice with a global deletion of the glucagon receptor gene (Gcgr) were designed using gene targeting. The phenotype of Gcgr−/−mouse provided important clues about the role of Gcgr in foetal growth, pancreatic development and glucose and lipid homeostasis. The lack of Gcgr activation was associated with: (i) hypoglycaemic pregnancies, poor foetal growth and increased foetal–neonatal demise; (ii) altered cytoarchitecture of pancreatic islets; (iii) altered glucose, lipid and hormonal milieu; (iv) reduced gastric emptying; (v) altered body composition and protection from diet‐induced obesity; (vi) altered energy state; (vii) impaired hepatocyte survival; (viii) altered metabolic response to prolonged fasting and exercise and (ix) prevented development of diabetes in insulin‐deficient mice. In contrast, mice overexpressing the Gcgr on pancreatic β‐cells displayed an increase insulin secretion, pancreatic insulin content and β‐cell mass, and partially protected against hyperglycaemia and impaired glucose tolerance when fed a high‐fat diet. These findings suggest that glucagon signalling plays a significant role in the regulation of glucose and lipid homeostasis. Treatment options designed to block Gcgr activation may have negative implications in the treatment of diabetes.
The role of dysregulated glucagon secretion in type 2 diabetes
Authors: D'Alessio D.
Published: August 2011

Excessive production of glucose by the liver contributes to fasting and postprandial hyperglycaemia, hallmarks of type 2 diabetes. A central feature of this pathologic response is insufficient hepatic insulin action, due to a combination of insulin resistance and impaired β‐cell function. However, a case can be made that glucagon also plays a role in dysregulated hepatic glucose production and abnormal glucose homeostasis. Plasma glucagon concentrations are inappropriately elevated in diabetic individuals, and α‐cell suppression by hyperglycaemia is blunted. Experimental evidence suggests that this contributes to greater rates of hepatic glucose production in the fasting state and attenuated reduction after meals. Recent studies in animal models indicate that reduction of glucagon action can have profound effects to mitigate hyperglycaemia even in the face of severe hypoinsulinaemia. While there are no specific treatments for diabetic patients yet available that act specifically on the glucagon signalling pathway, newer agents including glucagon‐like peptide‐1 (GLP‐1) receptor agonists and dipeptidyl peptidase‐4 (DPP‐4) inhibitors reduce plasma glucagon and this is thought to contribute to their action to lower blood glucose. The α‐cell and glucagon receptor remain tempting targets for novel diabetes treatments, but it is important to understand the magnitude of benefit new strategies would provide as preclinical models suggest that chronic interference with glucagon action could entail adverse effects as well.
Physiologic action of glucagon on liver glucose metabolism
Authors: Ramnanan C. J. , Edgerton D. S. , Kraft G. , Cherrington A. D.
Published: August 2011

Glucagon is a primary regulator of hepatic glucose production (HGP) in vivo during fasting, exercise and hypoglycaemia. Glucagon also plays a role in limiting hepatic glucose uptake and producing the hyperglycaemic phenotype associated with insulin deficiency and insulin resistance. In response to a physiological rise in glucagon, HGP is rapidly stimulated. This increase in HGP is entirely attributable to an enhancement of glycogenolysis, with little to no acute effect on gluconeogenesis. This dramatic rise in glycogenolysis in response to hyperglucagonemia wanes with time. A component of this waning effect is known to be independent of hyperglycemia, though the molecular basis for this tachyphylaxis is not fully understood. In the overnight fasted state, the presence of basal glucagon secretion is essential in countering the suppressive effects of basal insulin, resulting in the maintenance of appropriate levels of glycogenolysis, fasting HGP and blood glucose. The enhancement of glycogenolysis in response to elevated glucagon is critical in the life‐preserving counterregulatory response to hypoglycaemia, as well as a key factor in providing adequate circulating glucose for working muscle during exercise. Finally, glucagon has a key role in promoting the catabolic consequences associated with states of deficient insulin action, which supports the therapeutic potential in developing glucagon receptor antagonists or inhibitors of glucagon secretion.
Optimizing reduction in basal hyperglucagonaemia to repair defective glucagon counterregulation in insulin deficiency
Authors: Farhy L. S. , McCall A. L.
Published: August 2011

In health, the pancreatic islet cells work as a network with highly co‐ordinated signals over time to balance glycaemia within a narrow range. In type 1 diabetes (T1DM), with autoimmune destruction of the β‐cells, lack of insulin is considered the primary abnormality and is the primary therapy target. However, replacing insulin alone does not achieve adequate glucose control and recent studies have focused on controlling the endogenous glucagon release as well. In T1DM, glucagon secretion is disordered but not absolutely deficient; it may be excessive postprandially yet it is characteristically insufficient and delayed in response to hypoglycaemia. We review our system‐level analysis of the pancreatic endocrine network mechanisms of glucagon counterregulation (GCR) and their dysregulation in T1DM and focus on possible use of α‐cell inhibitors (ACIs) to manipulate the glucagon axis to repair the defective GCR. Our results indicate that the GCR abnormalities are of ‘network origin’. The lack of β‐cell signalling is the primary deficiency that contributes to two separate network abnormalities: (i) absence of a β‐cell switch‐off trigger and (ii) increased intraislet basal glucagon. A strategy to repair these abnormalities with ACI is proposed, which could achieve better control of glycaemia with reduced hypoglycaemia risk.
Metabolic impact of glucagon deficiency
Authors: Hayashi Y.
Published: August 2011

Multiple bioactive peptides are produced from proglucagon encoded by glucagon gene (Gcg). Glucagon is produced in islet α‐cells through processing by prohormone convertase 2 (Pcsk2) and exerts its action through the glucagon receptor (Gcgr). Although it is difficult to produce a genetic model that harbours isolated glucagon deficiency without affecting the production of other peptides derived from proglucagon, three different animal models that harbour deficiencies in glucagon signalling have been generated by gene targeting strategy. Although both Pcsk2−/− and Gcgr−/− mice display lower blood glucose levels, homozygous glucagon‐GFP knock‐in mice (Gcggfp/gfp) display normoglycaemia despite complete glucagon deficiency. In Gcggfp/gfp mice, the metabolic impact of glucagon deficiency is probably ameliorated by lower plasma insulin levels and glucagon‐independent mechanisms that maintain gluconeogeneis. As both Pcsk2−/− and Gcgr−/− mice exhibit increased production of glucagon‐like peptide‐1 (GLP‐1), which is absent in Gcggfp/gfp, GLP‐1 is the likely cause of the difference in metabolic impact of glucagon deficiency in these animal models. Although all the three models display islet ‘α’‐cell hyperplasia, the mechanisms involved remain to be elucidated. Studies using Pcsk2−/−, Gcgr−/− and Gcggfp/gfp mice, especially in combination with α‐cell ablation models such as pancreas‐specific aristaless‐related homeobox (ARX) knockout mice, should further clarify the physiological and pathological roles of glucagon in the regulation of metabolism and the control of islet cell differentiation and proliferation.
The future of incretin‐based therapy: novel avenues—novel targets
Authors: Ahrén B.
Published: August 2011

Incretin‐based therapy for type 2 diabetes is based on the antidiabetic effects of glucagon‐like peptide‐1 (GLP‐1) and instituted by GLP‐1 receptor agonists and dipeptidyl peptidase‐4 inhibitors targeting the key islet defects of the disease. The treatment is clinically efficient and safe, and associated with a low risk of adverse events. It can be used both in early and late stages of the disease and both as monotherapy and add‐on to other therapies. Current research on the future of incretin‐based therapy focuses on optimizing its place in diabetes treatment and examines its potential in type 1 diabetes, in subjects with obesity without type 2 diabetes and in cardiovascular and neurodegenerative disorders. Other studies aim at prolonging the duration of action of the GLP‐1 receptor agonists to allow weekly administration, and to develop orally GLP‐1 receptor agonists. Furthermore, other investigators focus on stimulation of GLP‐1 secretion by activating GLP‐1‐producing L‐cells or using gene therapy. Finally, also other gastro‐entero‐pancreatic bioactive peptides are potential targets for drug development as are synthetic peptides engineered as co‐agonists stimulating more than one receptor. We can therefore expect a dynamic development within this field in the coming years.
Eosinophilic keratoconjunctivitis in two rabbits
Authors: Grinninger Petra , Sanchez Rick , Kraijer‐Huver Ingrid M. G. , Kitslaar Willem‐Jan P. , Schoemaker Nico J. , Grinwis Guy C. M. , Boevé Michael H.
Published: August 2011

The purpose of this case report is to describe the clinical course and cytologic findings, treatment, and outcome of eosinophilic keratoconjunctivitis in two rabbits. Ophthalmic examination revealed ocular discharge, dacryocystitis, blepharitis, conjunctivitis, white conjunctival and corneal plaques, corneal vascularization, and stromal infiltration with different degrees of severity in each case. In case 2 there was also ulcerative disease of the cornea. Computerized tomography scan of the head, corneal biopsy for histopathologic examination with additional Luna and Giemsa stain were performed in case 2 and conjunctival as well as corneal specimens were obtained for bacteriologic culture and cytologic examination in case 1. Based on test results, a diagnosis of eosinophilic keratoconjunctivitis was made in case 2 and a tentative diagnosis of eosinophilic keratoconjunctivitis was made in case 1. Response to treatment with a topical steroid and topical cyclosporin was supportive of the diagnosis in both cases and shared many similarities with the response to treatment previously described in cats. Eosinophilic keratitis should be considered as part of a differential diagnosis list in rabbits with a history of keratitis.
Aqueous humor vascular endothelial growth factor in dogs: association with intraocular disease and the development of pre‐iridal fibrovascular membrane
Authors: Sandberg Christina A. , Herring Ian P. , Huckle William R. , LeRoith Tanya , Pickett J. Phillip , Rossmeisl John H.
Published: August 2011

Objective  To examine the concentrations of vascular endothelial growth factor (VEGF) in aqueous humor of dogs with intraocular disease and to evaluate the association of aqueous humor VEGF with pre‐iridal fibrovascular membrane (PIFM) formation.

Procedures  Two hundred and twenty six aqueous humor samples and 101 plasma samples were collected from 178 dogs with a variety of intraocular diseases (including cataract, primary glaucoma, uveitic glaucoma, aphakic/pseudophakic glaucoma, retinal detachment, lens luxation, and intraocular neoplasia), and aqueous humor was collected from 13 ophthalmically normal control dogs. Systemic disease status and administration of select medications were recorded. Aqueous and plasma VEGF was assayed via enzyme‐linked immunosorbant assay validated for canine VEGF. Available histopathology samples were examined for the presence of PIFM. Where present, PIFMs were categorized as none, cellular, vascular or fibrous, and fibrovascular. Data were evaluated by mixed model anova, with application of Tukey–Kramer adjustment for multiple comparisons.

Results  There was no association between aqueous humor and plasma VEGF levels. Compared with normal controls, aqueous humor VEGF was significantly elevated for all intraocular diseases (P < 0.05) except for primary and diabetic cataracts. Systemic disease and administered medications had no significant effect on aqueous humor VEGF concentration. Compared to dogs without PIFM, aqueous humor VEGF was significantly higher in dogs with fibrovascular PIFM (P = 0.001), but not cellular (P = 0.1704) or fibrous/vascular PIFM (P = 0.0667).

Conclusions  These findings confirm that VEGF is commonly elevated in aqueous humor of dogs with intraocular disease and likely plays a role in the causation or progression of a variety of intraocular disorders, including the development of PIFM.
Ectopic brain tissue in the retina of a beagle dog: a case report and literature review
Authors: Allavena Rachel E. , Phillips Keli , Andrews Marcus H.
Published: August 2011

Isolated ectopic brain tissue within the orbit is an extremely rare finding and has never been reported in dogs or other domestic species. In this case, a focal choristoma of ectopic grey matter‐like tissue was present within the retina of a mature female beagle dog, and consisted of neurons and astrocytes as demonstrated respectively by microtubule‐associated protein 2 and glial fibrillary acidic protein immunohistochemistry. The lesion was located within the optic fundus adjacent to the optic disk and surrounded by dysplastic retina. The case is presented with a review of literature on this rare entity.
A portable, contact animal fundus imaging system based on Rol’s GRIN lenses
Authors: Hernandez Victor , Albini Thomas , Lee William , Rowaan Cornelis , Nankivil Derek , Arrieta Esdras , Parel Jean‐Marie
Published: August 2011

Objective  To demonstrate a cost‐effective, portable, and simple‐to‐use fundus imaging system for laboratory animals.

Animals Studied  Albino rats, pigmented mice, albino guinea pigs, and New Zealand white rabbits.

Procedure  A contact fundus imaging system was designed and constructed using standard optical and mechanical components: a digital camera, an otoscope, a fiber optic light source, and standard optical lenses and mounts. Digital fundus video and photography of two albino rats, two pigmented mice, two New Zealand white rabbits, and two albino guinea pigs were obtained. For all animals examined, pupils were dilated and local anesthetic was administered.

Results  Digital images of the fundus were obtained in all animals. Contrast of retinal vasculature and overall image quality varied from one species to another, as the axial length, ocular optics, and retinal reflectance varied significantly across species. Light intensity and focus were optimized via the light source and lens focusing mount to produce high‐quality images for each animal.

Conclusions  The portable, cost‐effective contact fundus imaging system was easy to use for fundus examination of laboratory animals.
Risk of injury from alcohol and drug use in the emergency department: A case‐crossover study
Authors: CHERPITEL CHERYL J. , YE YU , WATTERS KATIE , BRUBACHER JEFFREY R. , STENSTROM ROB
Published: August 2011

Introduction and Aims. A substantial literature exists demonstrating the risk of injury from alcohol, but less is known about the association of alcohol in combination with other drugs and injury. This study examined the risk of injury associated with alcohol and drug use prior to the event.

Design and Methods. Case‐crossover analysis was used to estimate the relative risk (RR) of injury due to alcohol use alone, compared with alcohol in combination with other drug use in a sample of emergency department injured patients from two sites in Vancouver, British Columbia (n = 443). Alcohol and drug use in the 6 h prior to injury was compared with the patient's use of these substances during the same 6 h period the day prior and the week prior to injury.

Results. Using multiple matching for the two control time periods, RR of injury was significantly related to both alcohol use (RR = 3.3) and to alcohol combined with drug use (RR = 3.0), but not to drug use alone. Effect modification was found only for age for alcohol combined with drug use, with a significant increase in injury risk (P = 0.087) for those over 30.

Discussion and Conclusion. While a similar elevated risk of injury was found for alcohol use alone and alcohol used with other drugs, the literature suggests that alcohol in combination with some drugs may be potentially more risky for injury occurrence. Findings suggest the need for future research on risk of injury for specific alcohol and drug combinations.[Cherpitel CJ, Ye Y, Watters K, Brubacher JR, Stenstrom R. Risk of injury from alcohol and drug use in the emergency department: A case‐crossover study. Drug Alcohol Rev 2012;31:431–438]
Differential N‐glycosylation of a monoclonal antibody expressed in tobacco leaves with and without endoplasmic reticulum retention signal apparently induces similar in vivo stability in mice
Authors: Triguero Ada , Cabrera Gleysin , Rodríguez Meilyn , Soto Jeny , Zamora Yasser , Pérez Marlene , Wormald Mark R. , Cremata José A.
Published: August 2011

Plant cells are able to perform most of the post‐translational modifications that are required by recombinant proteins to achieve adequate bioactivity and pharmacokinetics. However, regarding N‐glycosylation the processing of plant N‐glycans in the Golgi apparatus displays major differences when compared with that of mammalian cells. These differences in N‐glycosylation are expected to influence serum clearance rate of plant‐derived monoclonal antibodies. The monoclonal antibody against the hepatitis B virus surface antigen expressed in Nicotiana tabacum leaves without KDEL endoplasmic reticulum (ER) retention signal (CB.Hep1(−)KDEL) and with a KDEL (Lys‐Asp‐Glu‐Leu) fused to both IgG light and heavy chains (CB.Hep1(+)KDEL) were tested for in vivo stability in mice. Full characterization of N‐glycosylation and aggregate formation in each monoclonal antibody batch was determined. The mouse counterpart (CB.Hep1) was used as control. Both (CB.Hep1(−)KDEL) and (CB.Hep1(+)KDEL) showed a faster initial clearance rate (first 24 h) compared with the analogous murine antibody while the terminal phase was similar in the three antibodies. Despite the differences between CB.Hep1(+)KDEL and CB.Hep1(−)KDEL N‐glycans, the in vivo elimination in mice was indistinguishable from each other and higher than the murine monoclonal antibody. Molecular modelling confirmed that N‐glycans linked to plantibodies were oriented away from the interdomain region, increasing the accessibility of the potential glycan epitopes by glycoprotein receptors that might be responsible for the difference in stability of these molecules.
Apoptosis‐related genes confer resistance to Fusarium wilt in transgenic ‘Lady Finger’ bananas
Authors: Paul Jean‐Yves , Becker Douglas K. , Dickman Martin B. , Harding Robert M. , Khanna Harjeet K. , Dale James L.
Published: August 2011

Fusarium wilt, caused by Fusarium oxysporum f. sp. cubense (Foc), is one of the most devastating diseases of banana (Musa spp.). Apart from resistant cultivars, there are no effective control measures for the disease. We investigated whether the transgenic expression of apoptosis‐inhibition‐related genes in banana could be used to confer disease resistance. Embryogenic cell suspensions of the banana cultivar, ‘Lady Finger’, were stably transformed with animal genes that negatively regulate apoptosis, namely Bcl‐xL, Ced‐9 and Bcl‐2 3′ UTR, and independently transformed plant lines were regenerated for testing. Following a 12‐week exposure to Foc race 1 in small‐plant glasshouse bioassays, seven transgenic lines (2 × Bcl‐xL, 3 × Ced‐9 and 2 × Bcl‐2 3′ UTR) showed significantly less internal and external disease symptoms than the wild‐type susceptible ‘Lady Finger’ banana plants used as positive controls. Of these, one Bcl‐2 3′ UTR line showed resistance that was equivalent to that of wild‐type Cavendish bananas that were included as resistant negative controls. Further, the resistance of this line continued for 23‐week postinoculation at which time the experiment was terminated. Using TUNEL assays, Foc race 1 was shown to induce apoptosis‐like features in the roots of wild‐type ‘Lady Finger’ plants consistent with a necrotrophic phase in the life cycle of this pathogen. This was further supported by the observed reduction in these effects in the roots of the resistant Bcl‐2 3′ UTR‐transgenic line. This is the first report on the generation of transgenic banana plants with resistance to Fusarium wilt.
Multi‐Level Democracy
Authors: MÖLLERS CHRISTOPH
Published: August 2011

Modern democratic polities regularly operate at several political levels. In the case of the EU at the level of the member‐states and the EU itself, and in addition at federal, regional, and municipal levels. Is there any democratic rule to determine which level is more legitimate than the others? The article argues that from a majoritarian perspective there is none. Individual citizens may have quite different preferences with regard to the level that is of particular political importance for them. The article critically analyses different concepts, from sovereignty to demos, subsidiarity, and the judicial review of competences, and tries to show that none of them can provide a solution to the dilemma. Instead, democratic theory has to assume that in the co‐evolutionary process of institutions and societies at different political levels, the question of the final say has to be left open.
Comparisons: colonial or cosmopolitan?
Authors: Robinson Jennifer
Published: August 2011

Editors' Note: The following is the ninth in the Singapore Journal of Tropical Geography Lecture Series. It is based on the plenary presentation of 3 September at the Annual Conference of the Royal Geography Society (with the Institute of British Geographers) held in London in 2010.

In the search for a more international approach to theorizing cities, comparative methods hold considerable promise, although one concern might be that in their theoretical ambitions they foster a universalising approach rather than one appreciative of diverse and sometimes divergent urban experiences. The potentially universalizing ambitions of comparative methods lead some postcolonial theorists to question the extent to which comparativism carries the marks of colonial histories. Critics argue that some aspects of formal comparative methods can be traced to ambitious and geographically encompassing intellectual projects from the colonial era, when the interest and capacity to bring different parts of the world together within the same intellectual frame advanced significantly. This paper explores the complexities of these colonial lineages of comparative research with a view to assessing their implications for postcolonial comparative urbanism. It concludes by assessing the potential for more modest comparative experiments in a postcolonial vein through attending to the diverse vernacular cosmopolitanisms of cities. Following the spatialities of cities themselves has the potential to offer non‐universalizing but variously internationalizing theoretical engagements with different places.
Protected areas in mainland Southeast Asia, 1973–2005: Continuing trends
Authors: Déry Steve , Vanhooren Romain
Published: August 2011

Since the 1970s, protected area networks in mainland Southeast Asian countries have developed significantly to occupy 4–25 per cent of their respective national areas, located mostly in the mountainous domains of ethnic minority peoples. Through this process, regions that were only nominally part of national geobodies until the 1950s have become more territorially integrated. The complexity of the characteristics and geographical impacts of this territorialisation have yet to be grasped. As a step in this direction, we briefly outline a multilevel systems approach that usefully contextualizes these issues together with a historical and cartographical assessment of the evolution of protected area networks for Burma, Thailand, Laos, Cambodia and Vietnam. Our main findings are intertwined. On the one hand, protected areas represent a new tool of state intervention in mountainous areas, clearly in keeping with past, notably colonial, actions. On the other hand, this evolution in state territorialisation and attendant power relations have disrupted, far more deeply than previous actions, the pre‐1970s sociogeographical organization in mountainous areas, where most of the region's residual forests remain.
Lusotropicalism: Tropical geography under dictatorship, 1926–1974
Authors: Pimenta José R. , Sarmento J. , de Azevedo Ana F.
Published: August 2011

This article locates Portuguese tropical geography within wider academic debates on ‘tropicality’, contributing to discussion on not only the ‘tropicality of geography’ but also the ‘geography of tropicality’. It traces the role of Portuguese tropical geography in the colonial project and in the production of geographical knowledge, discourses and imaginaries, in particular the emergence of lusotropicality. While noting the underestimated connections with developments in German and British geography, we argue that the genealogy of Portuguese tropical geography lies mostly within contemporaneous French developments. By focusing on the central role of the Lisbon school (i.e. the Centre for Geographical Studies established in 1943), and in particular the tropical research initiated by Orlando Ribeiro (1911–1997), the paper seeks to engage with the ways in which geographical knowledge was produced within the academic discipline in Portugal under military dictatorship associated with the Estado Novo (1926–1974). By decentring the exploration of some of the ways in which the ‘tropics’ have been constructed and revising forms of producing geographical knowledge, the paper hopes to further understandings of the geographical imaginary of the tropics, unravelling the history and the role of geography in colonialism.