Comparative analysis of the human dystrophin and utrophin gene structures

We present analysis of intronic sequences in the human DMD and UTRN genes. In both genes accumulation of repeated elements could account for intron expansion. Out-of-frame rod-domain exons have stronger splice sites and are separated by significantly longer introns as compared to in-frame exons. These features are unique for the two homologs and not shared by other spectrin superfamily genes.     

Functional and postural lateral preferences in humans: interrelations and life-span age differences

This study aimed to provide data on lateral preferences among older subjects, to analyze age differences, and to determine interrelations between lateral preferences. Four functional preferences (handedness, footedness, eyedness, earedness) and three postural lateral preferences (hand-clasping, arm-folding, leg-crossing) were assessed in 628 Germans (252 men, 376 women) aged between 19 and 90 years. Sex differences, age differences, and associations between lateralities were analyzed applying chi-square tests. Logistic regression analyses considering age, sex, and interactions between variables were applied to analyze combined effects on laterality measures. Right-sided preference for handedness, footedness, eyedness, earedness, and leg-crossing characterized 86.8%, 77.1%, 70.9%, 67.8%, and 56.6%, respectively, of subjects, while a left-sided preference for hand-clasping and arm-folding characterized 56.4% and 60.2%, respectively, of all participants. Results are within the range of other populations. Only footedness differed between the sexes: there were more left-footed men. Older cohorts showed a rightward shift in handedness, eyedness, earedness, and leg-crossing, the opposite for arm-folding. No age-related differences exist in footedness or hand-clasping. Logistic regression models indicate no interaction between age and sex for each laterality measure. The four functional lateralities are significantly interrelated. All also are positively associated with leg-crossing. Conversely, the postural lateralities generally are not correlated, although leg-crossing and arm-folding are, inversely. The observed relationships among lateralities support the hypothesis that handedness, footedness, leg-crossing, and earedness might be aspects of a larger phenotype that is independent of hand-clasping and arm-folding.     

Differential microbial clearance and immunoresponse of Balb/c (Nramp1 susceptible) and DBA2 (Nramp1 resistant) mice intracerebrally infected with Mycobacterium bovis BCG (BCG)

In mice, the gene encoding Nramp1 (natural resistance-associated protein 1) exists in two allelic forms, differing for a point mutation. According to Nramp1 genotype, extensive literature documents a clear-cut distinction of inbred strains in two non-overlapping groups that phenotypically express resistance (Nramp1r) and susceptibility (Nramp1s) to systemic infections. Here, we provide evidence that Nramp1r (DBA/2) and Nramp1s (Balb/c) mice differently handle intracerebral infection with Mycobacterium bovis BCG. Distinct trends of microbial clearance from the brain and also different patterns of local immune responses occur, thus arguing on the involvement of Nramp1 gene product on the accomplishment of cerebral anti-mycobacterial defenses.     

Genetic analysis of functions involved in the late stages of biofilm development in Burkholderia cepacia H111

Burkholderia cepacia and Pseudomonas aeruginosa often co-exist as mixed biofilms in the lungs of patients suffering from cystic fibrosis (CF). Here, we report the isolation of 13 random mini-Tn5 insertion mutants of B. cepacia H111 that are defective in biofilm formation on a polystyrene surface. We show that the screening procedure used in this study is biased towards mutants defective in the late stages of biofilm development. A detailed quantitative analysis of the biofilm structures formed by wild-type and mutant strains revealed that the isolated mutants are impaired in their abilities to develop a typical three-dimensional biofilm structure. Molecular investigations showed that the genes required for biofilm maturation fall into several classes: (i). genes encoding for surface proteins; (ii). genes involved in the biogenesis and maintenance of an integral outer membrane; and (iii). genes encoding regulatory factors. It is shown that three of the regulatory mutants produce greatly reduced amounts of N-octanoylhomoserine lactone (C8-HSL). This compound serves as the major signal molecule of the cep quorum-sensing system. As this density-dependent regulatory system is involved in the regulation of biofilm maturation, we investigated the interplay between the three regulatory genes and the quorum-sensing cascade. The results of these investigations show that the identified genes encode for regulatory elements that are positioned upstream of the cep system, indicating that the quorum-sensing system of B. cepacia is a major checkpoint for biofilm formation.     

Lateral organization of GM1 in phase-separated monolayers visualized by scanning force microscopy

Phase separation of glycolipids in lipid mono- and bilayers is of great interest for the understanding of membrane function. The distribution of the ganglioside GM1 in sphingomyelin (SM)/1-palmitoyl-2-oleoyl- sn-glycero-3-phosphocholine (POPC), SM/1,2-dipalmitoyl- sn-glycero-3-phosphocholine (DOPC) and SM/cholesterol/POPC Langmuir-Blodgett (LB) monolayers transferred at 36 mN/m has been studied by scanning force microscopy. Besides lateral organization of the glycolipid in LB monolayers as deduced from topography, material properties have been investigated by phase imaging, pulsed force mode and force modulation microscopy. It was shown that GM1 preferentially clusters in an ordered lipid matrix, i.e. the SM phase in the case of the SM/POPC and SM/DOPC mixture or in the ordered phase of POPC/SM/cholesterol monolayers. At higher local concentrations, three-dimensional protrusions enriched in GM1 occur, which may represent a precursor for the formation of micelles budding into the aqueous subphase. Electronic supplementary material to this paper can be obtained by using the Springer Link server located at http://dx.doi.org/10.1007/s00249-002-0232-4.     

Long-term suppression of pituitary-gonadal function with three-month depot of leuprorelin acetate in a girl with central precocious puberty

OBJECTIVE: The efficacy of a 3-month depot preparation of the GnRH agonist leuprorelin acetate in central precocious puberty was studied. METHODS: Treatment with a 3-month depot of leuprorelin acetate was performed subcutaneously in a 7.3-year-old girl with central precocious puberty. RESULTS: During treatment the hormonal suppression was constant and complete as demonstrated by suppressed GnRH stimulation tests and prepubertal estradiol plasma levels. The size and volume of the uterus and ovaries returned to the normal range. The rate of bone maturation was significantly reduced with a ratio deltaBA/deltaCA of 0.58 for 3 treatment years. Thus, the effects of treatment were comparable to those reported for treatment with 1-month depot of GnRH agonists. CONCLUSION: Three-month depots have the advantage of a prolonged injection interval which is more convenient for the patients and reduces costs by necessitating fewer visits to the physician and being approximately 10% cheaper than the 1-month depot. We suggest that comparative and randomized studies be performed to make 3-month depots of GnRH agonists available for routine use in children with central precocious puberty.     

The consequences of acute cold exposure on protein oxidation and proteasome activity in short-tailed field voles,microtus agrestis

During cold exposure, animals upregulate their metabolism and food intake, potentially exposing them to elevated reactive oxygen species (ROS) production and oxidative damage. We investigated whether acute cold (7 +/- 3 degrees C) exposure (1, 10, or 100 h duration) affected protein oxidation and proteasome activity, when compared to warm controls (22 +/- 3 degrees C), in a small mammal model, the short-tailed field vole Microtus agrestis. Protein carbonyls and the chymotrypsin-like proteasome activity were measured in plasma, heart, liver, kidney, small intestine (duodenum), skeletal muscle (gastrocnemius), and brown adipose tissue (BAT). Trypsin-like and peptidyl-glutamyl-like proteasome activities were determined in BAT, liver, and skeletal muscle. Resting metabolic rate increased significantly with duration of cold exposure. In skeletal muscle (SM) and liver, protein carbonyl levels also increased with duration of cold exposure, but this pattern was not repeated in BAT where protein carbonyls were not significantly elevated. Chymotrpsin-like proteasome activity did not differ significantly in any tissue. However, trypsin-like activity in SM and peptidyl-glutamyl-like activity in both skeletal muscle and liver, were reduced during the early phase of cold exposure (1-10 h), correlated with the increased carbonyl levels in these tissues. In contrast there was no reduction in proteasome activity in BAT during the early phase of cold exposure and peptidyl-glutamyl-like activity was significantly increased, correlated with the lack of accumulation of protein carbonyls in this tissue. The upregulation of proteasome activity in BAT may protect this tissue from accumulated oxidative damage to proteins. This protection may be a very important factor in sustaining uncoupled respiration, which underpins nonshivering thermogenesis at cold temperatures.