A role for Alström syndrome protein, alms1, in kidney ciliogenesis and cellular quiescence

Premature truncation alleles in the ALMS1 gene are a frequent cause of human Alstr?m syndrome. Alstr?m syndrome is a rare disorder characterized by early obesity and sensory impairment, symptoms shared with other genetic diseases affecting proteins of the primary cilium. ALMS1 localizes to centrosomes and ciliary basal bodies, but truncation mutations in Alms1/ALMS1 do not preclude formation of cilia. Here, we show that in vitro knockdown of Alms1 in mice causes stunted cilia on kidney epithelial cells and prevents these cells from increasing calcium influx in response to mechanical stimuli. The stunted-cilium phenotype can be rescued with a 5' fragment of the Alms1 cDNA, which resembles disease-associated alleles. In a mouse model of Alstr?m syndrome, Alms1 protein can be stably expressed from the mutant allele and is required for cilia formation in primary cells. Aged mice developed specific loss of cilia from the kidney proximal tubules, which is associated with foci of apoptosis or proliferation. As renal failure is a common cause of mortality in Alstr?m syndrome patients, we conclude that this disease should be considered as a further example of the class of renal ciliopathies: wild-type or mutant alleles of the Alstr?m syndrome gene can support normal kidney ciliogenesis in vitro and in vivo, but mutant alleles are associated with age-dependent loss of kidney primary cilia.     

Subcellular distribution,molecular dynamics and catabolism of plasmalogens in myocardium

Recent studies have implicated accelerated sarcolemmal phospholipid catabolism as a mediator of the lethal sequelae of atherosclerotic heart disease. We have demonstrated that plasmalogens are the predominant phospholipid constituents of canine myocardium and that plasmalogens are hydrolyzed by a novel calcium independent plasmalogen selective phospholipase A2. Since the activities of phospholipases are modulated by the molecular dynamics and interfacial characteristics of their phospholipid substrates, we compared the molecular dynamics of plasmenylcholine and phosphatidylcholine vesicles by electron spin resonance spectroscopy and deuterium magnetic resonance spectroscopy. Plasmenylcholine vesicles have separate and distinct molecular dynamics in comparisons to their phosphatidylcholine counterparts as ascertained by substantial decreases in the angular fluctuations and motional velocities of probes attached to their sn-2 aliphatic constituents. Furthermore, since free radical oxidation of myocardial lipid constituents occurs during myocardial ischemia and reperfusion, we demonstrated that ¹O₂ mediated oxidation of plasmenylcholine resulted in the generation of several products which have chromatographic characteristics and molecular masses corresponding to 2-acyl lysophosphatide derivatives. Taken together, these studies underscore the biologic significance of the predominance of sarcolemmal plasmalogens present in mammalian myocardium and suggest that their catabolism by plasmalogen selective phospholipases and/or oxidative processes may contribute to the lethal sequelae of myocardial ischemia.     

Protein and cDNA sequences of Bowman-Birk protease inhibitors from the cowpea (Vigna unguiculata Walp.)

The protein and gene sequences of the cowpea Bowman-Birk type trypsin inhibitor which confers enhanced insect resistance to transgenic tobacco plants, and of cowpea trypsin/chymotrypsin inhibitors are presented. There are regions of high conservation and high divergence within the 5 leader, mature protein and 3 non-coding regions of the Bowman-Birk inhibitors and in the genes which encode them in different members of this family within the Leguminosae. The practical implications of this finding for studies on the evolution of plants and the utilization of these genes for enhancing insect resistance is discussed.     

Interrelationship of kernel water activity,soil temperature,maturity, and phytoalexin production in preharvest aflatoxin contamination of drought-stressed peanuts

Samples of Florunner peanuts were collected throughout a period of late-season drought stress with mean geocarposphere temperatures of 29 and 25 °C, and determinations of maturity, kernel water activity (a_w), percent moisture, capacity for phytoalexin production, and aflatoxin contamination were made. Results showed an association between the loss of the capacity of kernels to produce phytoalexins and the appearance of aflatoxin contamination. Kernel a_w appeared to be the most important factor controlling the capacity of kernels to produce phytoalexins. Mature peanuts possessed additional resistance to contamination that could not be attributed solely to phytoalexin production. Kernel moisture loss was accelerated in the 29 °C treatment compared to the 25 °C treatment, and data indicated that the higher soil temperature also favored growth and aflatoxin production by Aspergillus flavus in peanuts susceptible to contamination.Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable.     

The effect of human C-reactive protein on the cell-attachment activity of fibronectin and laminin

We have previously reported that purified human C-reactive protein (CRP) specifically binds to the cell-binding region of plasma fibronectin (Fn) in a Ca2+-dependent reaction that is saturable at a molar ratio of CRP/Fn of approximately 9. In this study, the binding of CRP to Fn was found to interfere with the cell-attachment promoting activity of Fn. The inhibition of cell attachment was dependent on the concentration of the CRP and involved the phosphorylcholine (PC) binding site of CRP since inhibition was prevented by allowing the CRP to react with either PC (or closely related monophosphate compounds) or a mAb specific for the PC-binding site of CRP. Binding of CRP to laminin was also Ca2+-dependent; however, this binding did not alter the cell-attachment promoting activity of laminin. CRP by itself does not mediate cell attachment. Since CRP is selectively deposited at sites of tissue damage along with plasma Fn and has the ability to bind to Fn and alter its cell-binding activity, CRP may modulate early events in tissue repair.     

Signatures of demographic history and natural selection in the human major histocompatibility complex Loci

Many lines of evidence show that several HLA loci have experienced balancing selection. However, distinguishing among demographic and selective explanations for patterns of variation observed with HLA genes remains a challenge. In this study we address this issue using data from a diverse set of human populations at six classical HLA loci and, employing a comparative genomics approach, contrast results for HLA loci to those for non-HLA markers. Using a variety of analytic methods, we confirm and extend evidence for selection acting on several HLA loci. We find that allele frequency distributions for four of the six HLA loci deviate from neutral expectations and show that this is unlikely to be explained solely by demographic factors. Other features of HLA variation are explained in part by demographic history, including decreased heterozygosity and increased LD for populations at greater distances from Africa and a similar apportionment of genetic variation for HLA loci compared to putatively neutral non-HLA loci. On the basis of contrasts among different HLA loci and between HLA and non-HLA loci, we conclude that HLA loci bear detectable signatures of both natural selection and demographic history.     

Novel genetic polymorphisms that further delineate the phylogeny of the Mycobacterium tuberculosis complex

In a previous report, we described a PCR protocol for the differentiation of the various species of the Mycobacterium tuberculosis complex (MTC) on the basis of genomic deletions (R. C. Huard, L. C. de Oliveira Lazzarini, W. R. Butler, D. van Soolingen, and J. L. Ho, J. Clin. Microbiol. 41:1637-1650, 2003). That report also provided a broad cross-comparison of several previously identified, phylogenetically relevant, long-sequence and single-nucleotide polymorphisms (LSPs and SNPs, respectively). In the present companion report, we expand upon the previous work (i) by continuing the evaluation of known MTC phylogenetic markers in a larger collection of tubercle bacilli (n = 125), (ii) by evaluating additional recently reported MTC species-specific and interspecific polymorphisms, and (iii) by describing the identification and distribution of a number of novel LSPs and SNPs. Notably, new genomic deletions were found in various Mycobacterium tuberculosis strains, new species-specific SNPs were identified for "Mycobacterium canettii," Mycobacterium microti, and Mycobacterium pinnipedii, and, for the first time, intraspecific single-nucleotide DNA differences were discovered for the dassie bacillus, the oryx bacillus, and the two Mycobacterium africanum subtype I variants. Surprisingly, coincident polymorphisms linked one M. africanum subtype I genotype with the dassie bacillus and M. microti with M. pinnipedii, thereby suggesting closer evolutionary ties within each pair of species than had been previously thought. Overall, the presented data add to the genetic definitions of several MTC organisms as well as fine-tune current models for the evolutionary history of the MTC.     

Recent changes in body weight and wing length among some British passerine birds

We tested the prediction that global warming has caused recent decreases in body weight (Bergmann's rule) and increases in wing length (Allen's rule) in 14 species of passerine birds at two localities in England: Wicken Fen (1968–2003) and Treswell Wood (1973–2003).
Predicted long-term linear decreases in residual body weight occurred in four species: dunnocks (Wicken Fen), and great tits, blue tits and bullfinches (Treswell Wood). Non-linear decreases also occurred in reed warblers and blackcaps at Wicken Fen, which also had a surprising linear increase in residual body weight in blackbirds.
Residual wing lengths increased linearly, as predicted, in six of seven species at Wicken Fen. Whereas there were non-linear long-term increases in wrens, dunnocks and blackbirds in Treswell Wood. Unexpected linear decreases also occurred in residual wing lengths in willow warblers (Wicken Fen), and blue tits, great tits and chaffinches (Treswell Wood).
The most parsimonious explanation for such long-term changes in body weight is global warming, as predicted by Bergmann's rule. Greater site and species-specific effects on wing length (e.g. non-linear changes plus shorter wings in the woodland habitat) suggest a less straightforward conclusion concerning Allen's rule, probably because wing length involved variation in both bone and feather growth.
Changes in residual body weights and wing lengths often differed between species and were sometimes non-linear, perhaps reflecting short-term modifications in selection pressures. Human-induced influences are discussed, such as avian predator population densities and land-use change. Short-term variation in temperature had little effect, but rainfall did explain the unusual increase in blackbird body weight, possibly as a result of improving food (earthworm) availability.