Polymorphisms of vitamin D receptor gene in the population of eastern Croatia with psoriasis vulgaris and diabetes mellitus

The aim of this study was to evaluate the possible association between polymorphisms in the Vitamin D receptor gene (VDR gene) and tendency for development of psoriasis vulgaris and diabetes mellitus in the population of Slavonia, which is a region in the Eastern Croatia. In order to conduct the mentioned evaluation the restriction fragment length polymorphisms (ApaI, BsmI and TaqI) in the Vitamin D receptor gene were researched in three groups of patients: patients suffering only from psoriasis vulgaris, patients suffering only from diabetes mellitus, and patients suffering at the same time from both diseases. Four most common genotypes were found in all standardized control patients: triple heterozygotes BbAaTt (in 29.3% of the studied patients), bbAaTT (in 18.6% of the studied patients), bbaaTT (in 12.9% of the studied patients) and BbAATt (in 8.6% of the studied patients). Three most common VDR 3'-RFLP haplotypes determined in this study were: three-component baT, Bat and bAT haplotype. Results of the Hardy-Weinberg equilibrium showed presence of BsmI polymorphism genotype frequencies disequilibrium in the group of patients suffering from psoriasis and ApaI polymorphism in the group of patients suffering from both diseases. According to the same statistical test all conditions for TaqI polymorphism genotype frequency were fulfilled in all groups of studied patients. There was no significant difference in distribution of BsmI, ApaI or TaqI polymorphism genotype frequencies between control patients and any of the subgroup of studied patients. In studied population none of analysed polymorphisms individually was associated with the risk of development of psoriasis, diabetes or combined phenotype.     

The leaf turtle population of Phnom Kulen National Park (northwestern Cambodia) has genetic and morphological signatures of hybridization

Cambodia is known to harbour three distinct species of Southeast Asian leaf turtles (Cyclemys spp.), which are heavily traded and common in seizures of wildlife. Confiscated leaf turtles are often released to natural habitats. Thus, an exact knowledge of the distribution of the individual species is of great importance to avoid the introduction of non‐native turtles, posing the risk of competition and hybridization. In this study, we examine a recently discovered leaf turtle population from Phnom Kulen National Park using external morphology, 17 unlinked microsatellite loci and the mitochondrial cytochrome b gene. Leaf turtles from the Phnom Kulen National Park morphologically resemble C. oldhamii, but harbour mitochondrial haplotypes of C. atripons. With respect to microsatellite loci, the turtles are distinct from C. atripons. Unfortunately no material of C. oldhamii was available from Cambodia. We propose that the Phnom Kulen population represents either a natural hybrid swarm of C. atripons and C. oldhamii or a distinct undescribed species with introgressed mitochondria of C. atripons. This underlines that genetic differentiation of wild leaf turtle populations in Cambodia is complex and suggests that this differentiation pattern becomes increasingly threatened by translocations of confiscated individuals. For drawing a definite conclusion about the taxonomic status of the Phnom Kulen population, denser sampling of other Cambodian leaf turtle populations would be required, in particular of C. oldhamii.     

Monoamine Transporter Gene Expression in the Central Nervous System in Diabetes Mellitus

Abstract: Diabetic animals exhibit altered neurotransmission in brain monoaminergic systems. By means of in situ hybridization, we have investigated the expression of dopamine, noradrenaline, and serotonin transporter (DA-T, NA-T, and 5-HT-T, respectively) mRNAs in the brains of alloxan- and streptozotocin-diabetic rats. The expression of DA-T mRNA is decreased in 1- (−11%) and 4-(−17%) week alloxan-diabetic and 4- (−9%) and 8-(−20%) week streptozotocin-diabetic rats in the ventral medial bundle. The expression of NA-T mRNA is decreased in the locus coeruleus of 8- (−26%) week streptozotocin-diabetic rats, in the noradrenergic A1 cell group of 4-(−27%) week alloxan- and 8- (−25%) week streptozotocin-diabetic rats, and in the noradrenergic A2 cell group of 1- (−21%) and 4- (−28%) week alloxan-diabetic and 4- (−27%) and 8- (−25%) week streptozotocin-diabetic animals. The expression of 5-HT-T mRNA in the dorsal raphe nucleus is increased in 1- (+14%) and 4- (+44%) week alloxan- and 4- (+28%) and 8-(+44%) week streptozotocin-diabetic rats. The expression of each of the three monoamine transporter genes may be differentially regulated in diabetes and dependent on the duration of diabetes. Altered monoamine transporter gene expression may possibly contribute to the observed dysfunctions in brain monoamine transmission in chronic diabetes.     

Where are you from,stranger? The enigmatic biogeography of North African pond turtles (Emys orbicularis)

The European pond turtle (Emys orbicularis) is a Nearctic element in the African fauna and thought to have invaded North Africa from the Iberian Peninsula. All North African populations are currently identified with the subspecies E. o. occidentalis. However, a nearly range-wide sampling in North Africa used for analyses of mitochondrial and microsatellite DNA provides evidence that only Moroccan populations belong to this taxon, while eastern Algerian and Tunisian pond turtles represent an undescribed distinct subspecies. These two taxa are most closely related to E. o. galloitalica with a native distribution along the Mediterranean coast of northern Spain through southern France to western and southern Italy. This group is sister to a clade comprising several mitochondrial lineages and subspecies of E. orbicularis from Central and Eastern Europe plus Asia, and the successive sisters are E. o. hellenica and E. trinacris. Our results suggest that E. orbicularis has been present in North Africa longer than on the Iberian Peninsula and that after an initial invasion of North Africa by pond turtles from an unknown European source region, there was a phase of diversification in North Africa, followed by a later re-invasion of Europe by one of the African lineages. The differentiation of pond turtles in North Africa parallels a general phylogeographic paradigm in amphibians and reptiles, with deeply divergent lineages in the western and eastern Maghreb. Acknowledging their genetic similarity, we propose to synonymize the previously recognized Iberian subspecies E. o. fritzjuergenobsti with E. o. occidentalis sensu stricto. The seriously imperiled Moroccan populations of E. o. occidentalis represent two Management Units different in mitochondrial haplotypes and microsatellite markers. The conservation status of eastern Algerian pond turtles is unclear, while Tunisian populations are endangered. Considering that Algerian and Tunisian pond turtles represent an endemic taxon, their situation throughout the historical range should be surveyed to establish a basis for conservation measures.     

Bioassay Method in Evaluation of Trophic Conditions and Nutrient Limitation in the Danube Wetland Waters (1388–1426 r. km)

The algal growth potential (AGP) in water samples of the Danube wetland waters (1388–1426 r. km) as well as the effect of nitrogen (in final concentration of 0.16 g l⁻¹) and phosphorus enrichment (in final concentration of 0.02 g l⁻¹) on the AGP was investigated by miniaturized bioassay method. Values of the total biomass of Chlorella kessleri up to the 14th day of incubation were suitable for the evaluation of trophic conditions according to the classification of AGP. On the basis of the AGP results, trophic conditions in 55% of the samples were oligo-mesotrophic and in 46% of the samples meso-eutrophic. A statistically significant correlation (r = 0.34) was established between the AGP of C. kessleri in original water samples and NO₃ concentrations in situ. The TN/TP ratio in the wetland waters indicated a greater limitation due to nitrogen than phosphorous. Significantly lower TSI_TN than TSI_SD, TSI_Chla and TSI_TP indicated nitrogen limited conditions. In order to quantify established nutrient limitation by the bioassay method, the effect of added N and P concentrations on the growth rate of C. kessleri was expressed as the degree of nutrient limitation (Δr d⁻¹) during 7 days of incubation. In the Danube wetland waters only N limitation was established in June and July; N and P limitation in May and September while in August and October 2003 neither of the tested nutrients were limiting. From May to October 2003 the significantly highest degree of nitrogen (Δr = 0.736 d⁻¹) and phosphorus limitation (Δr = 0.474 d⁻¹) was determined in Lake Sakadaš.     

Alzheimer-like changes in protein kinase B and glycogen synthase kinase-3 in rat frontal cortex and hippocampus after damage to the insulin signalling pathway

The insulin-resistant brain state is related to late-onset sporadic Alzheimer's disease, and alterations in the insulin receptor (IR) and its downstream phosphatidylinositol-3 kinase signalling pathway have been found in human brain. These findings have not been confirmed in an experimental model related to sporadic Alzheimer's disease, for example rats showing a neuronal IR deficit subsequent to intracerebroventricular (i.c.v.) treatment with streptozotocin (STZ). In this study, western blot analysis performed 1 month after i.c.v. injection of STZ showed an increase of 63% in the level of phosphorylated glycogen synthase kinase-3alpha/beta (pGSK-3alpha/beta) protein in the rat hippocampus, whereas the levels of the unphosphorylated form (GSK-3alpha/beta) and protein kinase B (Akt/PKB) remained unchanged. Three months after STZ treatment, pGSK-3alpha/beta and Akt/PKB levels tended to decrease (by 8 and 9% respectively). The changes were region specific, as a different pattern was found in frontal cortex. Structural alterations were also found, characterized by beta-amyloid peptide-like aggregates in brain capillaries of rats treated with STZ. Similar neurochemical changes and cognitive deficits were recorded in rats treated with i.c.v. 5-thio-d-glucose, a blocker of glucose transporter (GLUT)2, a transporter that is probably involved in brain glucose sensing. The IR signalling cascade alteration and its consequences in rats treated with STZ are similar to those found in humans with sporadic Alzheimer's disease, and our results suggest a role for GLUT2 in Alzheimer's pathophysiology.     

Interplay between T cell receptor binding kinetics and the level of cognate peptide presented by major histocompatibility complexes governs CD8+ T cell responsiveness

Through a rational design approach, we generated a panel of HLA-A*0201/NY-ESO-1(157-165)-specific T cell receptors (TCR) with increasing affinities of up to 150-fold from the wild-type TCR. Using these TCR variants which extend just beyond the natural affinity range, along with an extreme supraphysiologic one having 1400-fold enhanced affinity, and a low-binding one, we sought to determine the effect of TCR binding properties along with cognate peptide concentration on CD8(+) T cell responsiveness. Major histocompatibility complexes (MHC) expressed on the surface of various antigen presenting cells were peptide-pulsed and used to stimulate human CD8(+) T cells expressing the different TCR via lentiviral transduction. At intermediate peptide concentration we measured maximum cytokine/chemokine secretion, cytotoxicity, and Ca(2+) flux for CD8(+) T cells expressing TCR within a dissociation constant (K(D)) range of ～1-5 μM. Under these same conditions there was a gradual attenuation in activity for supraphysiologic affinity TCR with K(D) < ～1 μM, irrespective of CD8 co-engagement and of half-life (t(1/2) = ln 2/k(off)) values. With increased peptide concentration, however, the activity levels of CD8(+) T cells expressing supraphysiologic affinity TCR were gradually restored. Together our data support the productive hit rate model of T cell activation arguing that it is not the absolute number of TCR/pMHC complexes formed at equilibrium, but rather their productive turnover, that controls levels of biological activity. Our findings have important implications for various immunotherapies under development such as adoptive cell transfer of TCR-engineered CD8(+) T cells, as well as for peptide vaccination strategies.     

Conservation genetics and phylogeography of the poorly known Middle Eastern terrapin Mauremys caspica (Testudines: Geoemydidae)

The West Asian stripe-necked terrapin Mauremys caspica is widespread throughout the Middle East—a region for which only few phylogeographic studies are available. Due to landscape alteration, pollution and intensification of water management, M. caspica is increasingly threatened. However, genetic diversity among and within populations is poorly known, impeding the identification of management units. Using a nearly rangewide sampling, we analyzed 14 microsatellite loci and mtDNA sequences in order to gain insight into the population structure and history of M. caspica. In agreement with a previous study, we found two clusters of mitochondrial haplotypes, with one cluster distributed in the east and the other in the west of the range. However, our microsatellite data suggested a more pronounced geographical structuring. When null alleles were coded as recessive with structure 2.3.2, three clusters were revealed, with one cluster matching roughly the range of the western mitochondrial cluster, and the composite ranges of the two other microsatellite clusters correspond to the distribution of the eastern mitochondrial cluster. Naïve structure analyses without correction for null alleles were congruent with respect to the two eastern microsatellite clusters, but subdivided the western cluster into two units, with an additional geographical divide corresponding to the ‘Anatolian diagonal’—a well-known high mountain barrier impeding exchange between western and eastern taxa. In naïve analyses, the westernmost microsatellite cluster (from Central Anatolia) is quite isolated from the others, and its distinctness is also supported by fixation indices resembling the values among the other three clusters. One of the two eastern clusters is distributed in the Caucasus region plus Iran, and terrapins from Saudi Arabia and Bahrain constitute the second eastern cluster, supporting the view that these endangered populations are native. Coalescent-based analyses of our microsatellite data reveal for all four clusters bottlenecks 4,000–20,000 years ago, suggesting that climatic fluctuations of the Late Pleistocene and Holocene played an important role in shaping current genetic diversity. We propose that each of the four identified clusters, including the Central Anatolian one, should be treated as a distinct management unit. The presence of non-native terrapins in the animal trade of Bahrain highlights the danger of genetic pollution of the endangered Arabian populations. Further sampling is needed to elucidate the situation in southern and central Iran and Iraq. Our results confirm that genetic data do not support the validity of any of the three morphologically defined subspecies of M. caspica, and we propose that their usage be abandoned.     

Tortoise (Reptilia,Testudinidae) radiations in Southern Africa from the Eocene to the present

Africa, inclusive of the West Indian Ocean islands, harbours 11 of the world's 16 extant testudinid genera. Fossil records indicate that testudinids originated in Asia and dispersed first to North America and Europe (Early Eocene) and later to Africa (Late Eocene). We used mitochondrial (1870 bp) and nuclear (1416 bp) DNA sequence data to assess whether molecular data support the late cladogenesis of Southern African testudinid lineages. Our results revealed strong support for the monophyly of a clade consisting of Kinixys, the two Malagasy genera and four Southern African genera (Psammobates, Stigmochelys, Homopus and Chersina). Kinixys diverged from this clade in the Late Palaeocene, suggesting that testudinids occupied Africa at an earlier date than indicated by fossil records. The Southern African tortoises consist of three, strongly supported clades: Psammobates + Stigmochelys; the five‐toed Homopus + Chersina; and the four‐toed Homopus. Due to the paraphyly of Homopus, we propose the taxonomic resurrection of Chersobius for the five‐toed Homopus species (boulengeri, signatus and solus). Cladogenesis at the genus level occurred mainly in the Eocene, with Chersina and Chersobius diverging in the Oligocene. The latter divergence coincided with species‐level radiations within Homopus (areolatus and femoralis) and Psammobates (oculifer, geometricus and tentorius). Our phylogeny could not resolve relationships within Psammobates, indicating rapid speciation between the Late Oligocene and Early Miocene. The Chersobius species were the last to diverge in the Early to Mid‐Miocene. By the Mid‐Miocene, P. tentorius started to differentiate into four lineages instead of the three recognized subspecies: P. t. tentorius, P. t. trimeni and two P. t. verroxii subclades occurring north and south of the Orange River, respectively. Terminal radiations in several taxa suggest the existence of cryptic species and a more diverse tortoise fauna than currently recognized. Factors contributing to this diversity may include the early origin of African testudinids and climatic fluctuations over a heterogeneous landscape.