LETM Proteins Play a Role in the Accumulation of Mitochondrially Encoded Proteins in Arabidopsis thaliana and AtLETM2 Displays Parent of Origin Effects

The Arabidopsis thaliana genome contains two genes with homology to the mitochondrial protein LETM1 (leucine zipper-EF-hand-containing transmembrane protein). Inactivation of both genes, Atletm1 and Atletm2, together is lethal. Plants that are hemizygous for AtLETM2 and homozygous for Atletm1 (letm1(−/−) LETM2(+/−)) displayed a mild retarded growth phenotype during early seedling growth. It was shown that accumulation of mitochondrial proteins was reduced in hemizygous (letm1(−/−) LETM2(+/−)) plants. Examination of respiratory chain proteins by Western blotting, blue native PAGE, and enzymatic activity assays revealed that the steady state level of ATP synthase was reduced in abundance, whereas the steady state levels of other respiratory chain proteins remained unchanged. The absence of a functional maternal AtLETM2 allele in an Atletm1 mutant background resulted in early seed abortion. Reciprocal crosses revealed that maternally, but not paternally, derived AtLETM2 was absolutely required for seed development. This requirement for a functional maternal allele of AtLETM2 was confirmed using direct sequencing of reciprocal crosses of Col-0 and Ler accessions. Furthermore, AtLETM2 promoter β-glucuronidase constructs displayed exclusive maternal expression patterns.     

Changes in surface-charge density of blood cells after sudden unexpected death

The objective of the investigation was evaluation of postmortem changes of electric charge of human erythrocyte and thrombocyte membranes after sudden unexpected death. The surface charge density values were determined on the basis of the electrophoretic mobility measurements of the cells carried out at various pHs of electrolyte solution. The interactions between both erythrocyte and thrombocyte membranes and electrolyte ions were studied. Values of parameters characterizing the membrane--that is, the total surface concentrations of both acidic and basic groups and their association constants with solution ions--were calculated on the basis of a four-equilibria mathematical model. The model was validated by comparison of these values to experimental data. We established that examined electric properties of the cell membranes are affected by sudden unexpected death. Postmortem processes occurring in the cell membranes can lead to disorders of existing equilibria, which in turn result in changes in values of all the above-mentioned parameters.     

Spermatological characters of monozoic tapeworms (Cestoda: Caryophyllidea), including first data on a species from the Indomalayan catfish

The ultrastructure of spermiogenesis and mature spermatozoon in Lytocestus indicus (Cestoda: Lytocestidae) is described; this is the first representative of this group of monozoic, presumably most basal, tapeworms (Eucestoda) from the Indomalayan region to be documented in this manner. Similarly, as in other caryophyllideans, its spermiogenesis involves the formation of a conical differentiation zone with 2 centrioles associated with striated roots and an intercentriolar body. In the course of the process, 1 of the centrioles develops a free flagellum, which fuses with a cytoplasmic protrusion, whereas the other remains oriented in a cytoplasmic bud. Spermiogenesis is also characterized by the presence of electron-dense material in the early stages of spermiogenesis and a slight rotation of the flagellar bud. The mature spermatozoon of L. indicus is a filiform cell tapered at both extremities that lacks mitochondria; its nucleus has parallel disposition to the axoneme and does not reach up to the posterior extremity of the spermatozoon, which is typical for spermatozoa of the type III pattern. The new data confirm that caryophyllideans share the same type of spermiogenesis that is considered to be plesiomorphic in the Eucestoda. The existing information on spermatological ultrastructure of 8 members for 3 of 4 caryophyllidean families from different host groups (cyprinids and catostomids, both Cypriniformes, and mochokids and clariids, both Siluriformes) from 4 zoogeographical regions (Palearctic, Neotropic, Ethiopian, and Indomalayan regions) demonstrates great uniformity in spermiogenesis and sperm ultrastructure, which does not reflect different taxonomic position of the species studied.     

Dysfunctional HDL: A novel important diagnostic and therapeutic target in cardiovascular disease?

High density lipoprotein (HDL) has many properties, which contribute to its atheroprotective role. However, some recent clinical trials have identified subjects with the progression of atherosclerosis despite normal levels of HDL cholesterol. This raises the question if all subfractions of HDL have the same properties. Moreover, recent investigations have shown that both acute and chronic inflammation may lead to structural and functional changes of HDL, which render the particles proinflammatory. Although therapeutic agents that increase HDL levels are now quite well established it is not clear whether they influence HDL quality. We review the current state of knowledge on the properties of HDL and factors/therapeutic agents which may restrain the transformation of normal HDL into dysfunctional HDL.     

Descriptions of digeneans from <Emphasis Type="Italic">Sardina pilchardus</Emphasis> (Walbaum) (Clupeidae) off the Algerian coast of the western Mediterranean,with a complete list of its helminth parasites

Five species of digeneans parasitic in the pilchard Sardina pilchardus (Walbaum), a little studied host, from off the Algerian coast of the western Mediterranean are redescribed. These are Parahemiurus merus (Linton, 1910) Manter, 1940, Aphanurus stossichii (Monticelli, 1891) Looss, 1907, Aphanurus virgula Looss, 1907, Lecithaster confusus Odhner, 1905 and Pronoprymna ventricosa (Rudolphi, 1819) Poche, 1926. One of these, A. virgula, is a new record for this host. One other digenean, Hemiurus luehei Odhner, 1905, was also recorded from this host. A complete checklist of the helminth parasites of S. pilchardus throughout its distributional range, comprising 104 host-parasite records of 39 taxa, is presented.     

Discrepancy between clinical and histological effects of DHA supplementation in a rat model of pouchitis

Docosahexaenoic acid (DHA) potentially modulates inflammatory processes. Therefore, the aim of this study was to determine the influence of DHA supplementation on the expression of intestinal inflammation and nutritional status in rats which have undergone restorative proctocolectomy. Twenty-four Wistar rats were operated. After the induction of pouchitis, animals were randomly divided into a control group (CG) and supplementation groups receiving respectively a semi-synthetic diet without or with DHA (in a lower or higher dose, respectively known as the lower dose, LD, and higher dose, HD, groups) for six weeks. Selected nutritional parameters were assessed. Histopathological and immunohistochemical analysis of pouch mucosa specimens was also performed. The effectiveness of feeding and quality of stools were significantly better in the HD group than in the CG. The intensity of inflammation (Moskovitz scale) was higher in HD and LD than in CG (p = 0.03 and p = 0.0006, respectively). Nevertheless, pouch adaptation (Laumonier scale) was more significant in LD than in CG (p = 0.007). On the other hand, tissue expression of IL-1α and IL-10 was higher in HD and LD than in CG (IL-1α, p = 0.009 and p = 0.05, respectively; IL-10, p = 0.04 for both). DHA supplementation has no impact on body weight gain. Yet it seems that it may improve the effectiveness of nutrition and stool quality in rats which have undergone restorative proctocolectomy. Simultaneously, it increases the intensity of pouch adaptation and inflammation. The specificity of observed changes is not clear. However, it may imply potential modulation of inflammatory processes of pouch mucosa.     

Floral structure and pollen morphology of two zinc violets (Viola lutea ssp. calaminaria and V. lutea ssp. westfalica) indicate their taxonomic affinity to Viola lutea

Two zinc violets, the yellow form of the Aachen–Liège area and the blue morph of Blankenrode in western Westphalia, have very restricted occurrence on heavy metal waste heaps. Their taxonomic affinities have not been finally resolved. The flower micromorphological analysis presented here indicates that both zinc violets are closely related to the alpine Viola lutea, in line with our earlier published molecular data, but not with the conclusions of other authors. The zinc violets are classed at the rank of subspecies as V. lutea: ssp. calaminaria for the yellow zinc violet and ssp. westfalica for its blue counterpart. Although the violets examined (V. lutea, V. lutea ssp. calaminaria, V. lutea ssp. westfalica) are closely related, there is no evidence that V. lutea ssp. westfalica is a descendent of V. tricolor. Here we provide the most detailed information on generative organ structure in the four violets studied.     

Pooled sample-based GWAS: a cost-effective alternative for identifying colorectal and prostate cancer risk variants in the Polish population

Background

Prostate cancer (PCa) and colorectal cancer (CRC) are the most commonly diagnosed cancers and cancer-related causes of death in Poland. To date, numerous single nucleotide polymorphisms (SNPs) associated with susceptibility to both cancer types have been identified, but their effect on disease risk may differ among populations.

Methods

To identify new SNPs associated with PCa and CRC in the Polish population, a genome-wide association study (GWAS) was performed using DNA sample pools on Affymetrix Genome-Wide Human SNP 6.0 arrays. A total of 135 PCa patients and 270 healthy men (PCa sub-study) and 525 patients with adenoma (AD), 630 patients with CRC and 690 controls (AD/CRC sub-study) were included in the analysis. Allele frequency distributions were compared with t-tests and χ²-tests. Only those significantly associated SNPs with a proxy SNP (p<0.001; distance of 100 kb; r²>0.7) were selected. GWAS marker selection was conducted using PLINK. The study was replicated using extended cohorts of patients and controls. The association with previously reported PCa and CRC susceptibility variants was also examined. Individual patients were genotyped using TaqMan SNP Genotyping Assays.

Results

The GWAS selected six and 24 new candidate SNPs associated with PCa and CRC susceptibility, respectively. In the replication study, 17 of these associations were confirmed as significant in additive model of inheritance. Seven of them remained significant after correction for multiple hypothesis testing. Additionally, 17 previously reported risk variants have been identified, five of which remained significant after correction.

Conclusion

Pooled-DNA GWAS enabled the identification of new susceptibility loci for CRC in the Polish population. Previously reported CRC and PCa predisposition variants were also identified, validating the global nature of their associations. Further independent replication studies are required to confirm significance of the newly uncovered candidate susceptibility loci.