Oligomerization of deoxynucleoside-bisphosphate dimers: Template and linkage specificity

Evidence is presented that a poly(U) template selectively favors the oligomerization of the activated, 3–5 pyrophosphate-linked dimer pdAppdAp, in comparison with the 3–3 and 5–5 linked dimers. In the absence of poly(U), the 5–5linked dimer is the most reactive, and chains are formed which are more than 60 monomer units in length.Nucleic Acid-Like Structures V. For the previous paper in this series see Visscher and Schwartz (1988).     

Phylogenetic relationships of finches and allies based on nuclear and mitochondrial DNA

The complete mitochondrial gene cytochrome b in combination with a nuclear gene, beta-fibrinogen intron 7, is sequenced for different groups of mostly granivorous species in the superfamily Passeroidea, with a focus on the estrildids and fringillids. From our study we can conclude that within the group of granivorous finches two clades can be distinguished, the estrildid weaver clade and the cardueline, fringillid, emberizid, passerine sparrow clade. In contrast to many other studies the passerine sparrows are not placed within the weavers estrildid clade which is in agreement with other recent studies (e.g., ). Our study also shows that the estrildids do form a monophyletic group, but there is a division based on geographic origin: an African group and an Asian-Australian group. Within the Fringillidae the Fringilla species are the sister group of the carduelines.     

Structure of the human argininosuccinate synthetase gene and an improved system for molecular diagnostics in patients with classical and mild citrullinemia

Deficiency of argininosuccinate synthetase (ASS) causes citrullinemia, an autosomal recessive inherited defect of the urea cycle. Most patients described so far have presented with the classical form of the disease. There are also patients with a mild form of citrullinemia in whom the exact molecular basis and clinical relevance are uncertain. Mutations in the human ASS gene have not yet been described in mildly affected or asymptomatic patients with citrullinemia. The genomic sequence of the human ASS gene is not precisely known making mutation analysis difficult. Here, the entire genomic DNA sequence and mutations in the ASS gene of patients with the classical and mild form of the disease are described. The mutations c.1168G-->A (G390R) and IVS13+5 G-->A and the novel mutation c.323G-->T (R108L) have been found to be associated with classical citrullinemia, whereas the novel mutations c.535T-->G (W179R), and c.1085G-->T (G362V) have been detected on alleles of the mildly affected patients. Thus, mutations found in the human ASS gene of asymptomatic children with biochemical abnormalities and in some cases enzymatically proven citrullinemia have allowed us to classify these cases as ASS-deficient patients. The elucidation of the structure of the human ASS gene has made possible the use of intronic primers for molecular analysis of patients with mild disease and the classical form, and provides another option for prenatal diagnostics in affected families with the severe type.     

Detection and identification of FaeC as a minor component of K88 fibriilae of Escherichia coli

A tribrid gene containing ompF, faeC, and lacZ sequences was constructed by subcloning a large central segment of the K88ab gene encoding the fibrillar subunit-like protein FaeC into the open reading frame expression vector pORF2. The resulting tribrid protein was isolated and used to raise antibodies against the FaeC protein. These antibodies were then used for the detection and subcellular localization of the FaeC protein in Escherichia coli harbouring the K88ab-encoding plasmid pFM205 or mutant derivatives. Immunoblotting of subcellular fractions and of purified fibrillae, and agglutination experiments using whole cells revealed that the FaeC protein is present in the periplasm and as a minor component in the K88ab fibrillae. FaeC was also detected in purified K88ac and K88ad fibrillae. Immunoelectron microscopy confirmed the presence of FaeC in K88ab fibrillae, particularly at the tips of the longer fibrillae.     

Local above‐ground persistence of vascular plants: Life‐history trade‐offs and environmental constraints

Questions: 1. Which plant traits and habitat characteristics best explain local above‐ground persistence of vascular plant species and 2. Is there a trade‐off between local above‐ground persistence and the ability for seed dispersal and below‐ground persistence in the soil seed bank? Locations: 845 long‐term permanent plots in terrestrial habitats across the Netherlands. Methods: We analysed the local above‐ground persistence of vascular plants in permanent plots (monitored once a year for ca. 16 year) with respect to functional traits and habitat preferences using survival statistics (Kaplan‐Meier analysis and Cox’ regression). These methods account for censored data and are rarely used in vegetation ecology. Results: Local above‐ground persistence is determined by both functional traits (especially the ability to form long‐lived clonal connections) and habitat preferences (especially nutrient requirements). Above‐ground persistence is negatively related to the ability for dispersal by wind and to the ability to accumulate a long‐term persistent soil seed bank (‘dispersal through time’) and is positively related to the ability for dispersal by water. Conclusions: Most species have a half‐life expectation over 15 years, which may contribute to time lags after changes in habitat quality or ‐configuration (‘extinction debt’). There is evidence for a trade‐off relationship between local above‐ground persistence and below‐ground seed persistence, while the relationship with dispersal in space is vector specific. The rate of species turnover increases with productivity.     

Cigarette smoke-induced blockade of the mitochondrial respiratory chain switches lung epithelial cell apoptosis into necrosis

Increased lung cell apoptosis and necrosis occur in patients with chronic obstructive pulmonary disease (COPD). Mitochondria are crucially involved in the regulation of these cell death processes. Cigarette smoke is the main risk factor for development of COPD. We hypothesized that cigarette smoke disturbs mitochondrial function, thereby decreasing the capacity of mitochondria for ATP synthesis, leading to cellular necrosis. This hypothesis was tested in both human bronchial epithelial cells and isolated mitochondria. Cigarette smoke extract exposure resulted in a dose-dependent inhibition of complex I and II activities. This inhibition was accompanied by decreases in mitochondrial membrane potential, mitochondrial oxygen consumption, and production of ATP. Cigarette smoke extract abolished the staurosporin-induced caspase-3 and -7 activities and induced a switch from epithelial cell apoptosis into necrosis. Cigarette smoke induced mitochondrial dysfunction, with compounds of cigarette smoke acting as blocking agents of the mitochondrial respiratory chain; loss of ATP generation leading to cellular necrosis instead of apoptosis is a new pathophysiological concept of COPD development.     

Influence of lighting environment on social preferences in sticklebacks from two different photic habitats. II. Shoaling and mate preferences of lab-bred fishes

Different environmental conditions may lead to diverse morphological, behavioral, and physiological adaptations of different populations of the same species. Lighting conditions, for example, vary vastly especially between aquatic habitats, and have been shown to elicit adaptations. The availability of short-wave ultraviolet (UV) light is especially fluctuating, as UV wavelengths are attenuated strongly depending on water properties. The island of North Uist, Scotland, comprises 2 differential habitat types, tea-stained and clear-water lakes, varying considerably in UV transmission. In previous studies, wild-caught 3-spined stickleback Gasterosteus aculeatus populations (3 populations of each habitat type) were tested with respect to their shoaling and mate preferences for fish viewed under UV-present and UV-absent conditions. The results revealed a habitat-dependent preference of UV cues during shoal choice (tea-stained populations: preference for UV-absent condition in tea-stained water; clear-water populations: no preference in clear-water) but an overall preference for UV-present conditions during mate choice. To assess genetic influences on these behavioral patterns, similar experiments were conducted with lab-bred F1-generations of the same stickleback populations that were raised in a common environment (i.e. standardized clear-water conditions). Offspring of sticklebacks from tea-stained lakes tended to prefer shoals viewed under UV-absent conditions (only in tea-stained water), while sticklebacks from clear-water lakes showed a significant preference for the shoal viewed under UV-present conditions in clear-water but not in tea-stained water. Mate-preference experiments demonstrated that females from the tea-stained lakes significantly preferred and females from the clear-water lakes preferred by trend the male viewed under UV-present conditions in the clear-water treatment. The results for both shoaling- and mate-preference tests were largely similar for wild-caught and lab-bred sticklebacks, thus hinting at a genetic basis for the preference patterns.     

Fijian Business—a Bone of Contention. Was it One of the Factors Leading to the Political Crisis of 2000?

In this paper I seek to cast light on a particular aspect of the background for the political crisis in Fiji in 2000. Before and during this crisis politicians and media kept hammering on the theme of Fijians' inferior position in the economic life of the country. The public argument in Fiji further emphasised the success of the Indians and that this in turn further marginalised the Fijians. It was frequently asserted that the Fijians needed affirmative action in order to get on in the modern business world and that the new Prime Minister Mahendra Chaudhry was favouring the Indians. The theme of this article is that the rhetoric used prior to and during the crisis was a reiteration of a longstanding discourse in Fiji. Similar arguments were used in the 1970s and 1980s, particularly as a means of legitimating the coup in 1987, and during the regime of Rabuka in the 1990s. My primary concern here is not to document the success or failure of Fijians in modern business enterprises, but rather to make clear how the dichotomy of business‐vanua comprises a variety of concerns and doubts related to modernisation, urbanisation, ethnicity, belonging, values and choices. By constantly discussing and exposing the interface between business and vanua, money and land, people seek to make sense of complex urban situations. The ongoing debate may be looked upon as a ‘work of coherence’ in Hannerz’ terms, and as such is a debate on modernity.     

Toll-Like Receptor Family Polymorphisms Are Associated with Primary Renal Diseases but Not with Renal Outcomes Following Kidney Transplantation

Toll-like receptors (TLRs) play a crucial role in innate- and adaptive immunity. The TLR pathways were shown to play key functional roles in experimental acute and chronic kidney injury, including the allo-immune response after experimental renal transplantation. Data about the precise impact of TLRs and their negative regulators on human renal transplant outcomes however are limited and contradictory. We studied twelve non-synonymous single nucleotide polymorphisms (SNPs) of which eleven in TLR1-8 and one in SIGIRR in a final cohort comprising 1116 matching donors and recipients. TLR3 p.Leu412Phe and SIGIRR p.Gln312Arg significantly deviated from Hardy-Weinberg equilibrium and were excluded. The frequency distribution of the minor alleles of the remaining 10 TLR variants were compared between patients with end-stage renal disease (recipients) and controls (kidney donors) in a case-control study. Secondly, the associations between the minor allele frequency of the TLR variants and delayed graft function, biopsy-proven acute rejection and death-censored graft failure after transplantation were investigated with Cox regression. Carrier frequencies of the minor alleles of TLR1 p.His305Leu (OR = 4.79, 95% CI = 2.35–9.75, P = 0.0002), TLR1 p.Asn248Ser (OR = 1.26, 95% CI = 1.07–1.47, P = 0.04) and TLR8 p.Met1Val (OR = 1.37, 95% CI = 1.14–1.64, P = 0.008) were significantly higher in patients with ESRD, with little specificity for the underlying renal disease entity (adjusted for age, gender and donor-recipient relatedness). The minor allele frequency of none of the TLR variants significantly associated with the surrogate and definite outcomes, even when multivariable models were created that could account for TLR gene redundancy. In conclusion, genetic variants in TLR genes were associated with the prevalence of ESRD but not renal transplant outcomes. Therefore, our data suggests that specific TLR signaling routes might play a role in the final common pathway of primary renal injury. A role for TLR signaling in the context of renal transplantation is probably limited.