Different repetition frequencies of a 120 base-pair DNA-element and its arrangement in Chironomus thummi thummi and Chironomus thummi piger

The repetition frequency of a highly repetitive DNA sequence has been measured in the genomes of Ch. thummi thummi and Ch. th. piger. This sequence is known to be involved in the evolutionary duplication of defined chromosomal segments leading to a significant increase in the genome size of Ch. th. thummi. Reassociation of this highly repetitive DNA sequence which has a repeat length of 120 base-pairs, with total Ch. th. thummi and Ch. th. piger DNA has shown that the repetition frequency in the Ch. th. thummi DNA is 5.5 fold higher than in Ch. th. piger. In both genomes a 120 base-pair sequence is present as tandemly repeated sequence as shown by Southern analysis.     

Preparation of membrane vesicles from isolated myelin: studies on functional and structural properties.

Myelin membranes purified from bovine brain are shown to form membrane vesicles when incubated in hypotonic buffer. Following restoration of isotonicity a resealing of the membrane occurs as judged by a significant decrease in 22Na+ permeability. Electron spin resonance measurements using stearic acid spin label I indicate a small decrease in membrane fluidity with increasing ionic strength between 50 and 80 mM NaCl. Iodination of myelin membrane vesicles by lactoperoxidase shows a four-fold increase in the amount of iodine incorporation into the myeline basic protein from 0--150 mM NaCl, while the iodination of the proteolipid protein remains essentially unaffected by the change in ionic strength. This dependence of the iodination of the myelin basic protein on the ionic strength can be explained by the electrostatic interactions of this protein with membrane lipids. In view of striking analogies with studies on model membranes correlating protein binding with membrane permeability changes, we suggest a similar structure-function relationship for the myelin basic protein.     

Seasonal fluctuations of food intake and bodyweight in the dormouse Glis glis (author's transl)]

Cycles of body weight lasting a few weeks occurred in dormice fed ad libitum, throughout the year with the same food. The pattern of the fluctuations suggests an oscillation between an upper and a lower limit. When the lower limit is reached, compensatory mechanisms acting on the food intake are induced which cause an increase in body weight to the upper one; when this upper limit is reached, other mechanisms cause the body weight to decrease to the lower one. Thus, body weight and variations in food intake may well be controlled by the difference between the body weight and the limit it will reach. In a warm environment (23-25 degrees C) these fluctuations are smaller than in the cold (5-6 degrees C). They are also smaller during summer than during winter in animals placed in natural climatic conditions. In summer, the body weight stays near the upper limit; in this season, as in the warm environment, the lower limit approaches the upper one. Thus, the main circannual variation of body weight regulation in dormice may be the elevation during summer of the lower body weight limit.     

Characterization of the cDNA coding for mouse prothrombin and localization of the gene on mouse chromosome 2

A series of overlapping cDNAs coding for mouse prothrombin (coagulation factor II) have been isolated and the composite DNA sequence has been determined. The complete prothrombin cDNA is 1,987 bp in length [excluding the poly(A) tail] and codes for 18 bp of 5' untranslated sequence, an open reading frame coding for 618 amino acids, a stop codon, and a 3' untranslated region of 112 bp followed by a poly(A) tail. The translated amino acid sequence predicts a molecular weight of 66,087, which includes 10 residues of gamma-carboxyglutamic acid. There are five potential N-linked glycosylation sites. Mouse prothrombin is 81.4% and 77.3% identical to the human and bovine proteins, respectively. Comparison of the cDNA coding for mouse prothrombin to the human and bovine cDNAs indicates 79.9% and 76.5% identity, respectively. Amino acid residues important for the structure and function of human prothrombin are conserved in the mouse and bovine proteins. In the adult mouse and rat, prothrombin is primarily synthesized in the liver, where is constitutes 0.07% of total mRNA as determined by solution hybridization analysis. The genetic locus for mouse prothrombin, Cf-2, has been mapped using an interspecies backcross and DNA fragment differences between the two species. The prothrombin locus lies on mouse chromosome 2, 1.8 +/- 1.3 map units proximal to the catalase locus. The gene order in this region is Cen-Acra-Cf-2-Cas-1-A-Tel. This localization extends the proximal boundary of the known region of homology between mouse chromosome 2 and human chromosome 11p from Cas-1 about 2 map units toward the centromere.     

Hormonally induced elevations of alpha- and beta-casein mRNA levels are blocked by cyclic adenine nucleotide and prostaglandins

Normal mammary gland development during pregnancy follows a coordinated program of morphological development (formation of lobuloalveoli) and biochemical differentiation (casein production). In culture, whole mammary glands of Balb/c mice can be similarly induced by application of a mixture of insulin, prolactin, aldosterone and hydrocortisone (IPAH) for 7 days. Our previous reports have shown that lobuloalveolar development, induced by IPAH, is competitively inhibited by the simultaneous presence of dibutyryl cyclic AMP (Bt2cAMP), prostaglandins (PGs) E1, E2, and B1, and papaverine (pap). However, if this mixture is not added until day 4, lobuloalveolar development is relatively unaffected but casein synthesis is repressed. This report explores the mechanism by which cyclic adenine nucleotides and prostaglandins interfere with the normal developmental pathway. The accumulation of alpha- and beta-casein mRNAs induced by prolactin, hydrocortisone and aldosterone is blocked by the combination of Bt2cAMP, PGs E1, E2, and B1, and pap added to the medium for the final 3 days (days 4-7). Under these conditions the glands retain their lobuloalveoli, and little squamous metaplasia can be discerned. Furthermore, de novo synthesis of both caseins is selectively inhibited, despite the continued presence of casein mRNAs in the glands and normal protein synthesis. In contrast, the synthesis of keratin is stimulated. Incomplete mixtures of Bt2cAMP and pap or the combination of PGs E1, E2, and B1, are only partly effective in preventing the accumulation of casein mRNAs. All three mixtures bring about similar effects on both alpha- and beta-casein mRNAs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Beyond ecosystem modeling: A roadmap to community cyberinfrastructure for ecological data‐model integration

In an era of rapid global change, our ability to understand and predict Earth's natural systems is lagging behind our ability to monitor and measure changes in the biosphere. Bottlenecks to informing models with observations have reduced our capacity to fully exploit the growing volume and variety of available data. Here, we take a critical look at the information infrastructure that connects ecosystem modeling and measurement efforts, and propose a roadmap to community cyberinfrastructure development that can reduce the divisions between empirical research and modeling and accelerate the pace of discovery. A new era of data‐model integration requires investment in accessible, scalable, and transparent tools that integrate the expertise of the whole community, including both modelers and empiricists. This roadmap focuses on five key opportunities for community tools: the underlying foundations of community cyberinfrastructure; data ingest; calibration of models to data; model‐data benchmarking; and data assimilation and ecological forecasting. This community‐driven approach is a key to meeting the pressing needs of science and society in the 21st century.     

Oil palm and rubber expansion facilitates earthworm invasion in Indonesia

Deforestation, plantation expansion and other human activities in tropical ecosystems are often associated with biological invasions. These processes have been studied for above-ground organisms, but associated changes below the ground have received little attention. We surveyed rainforest and plantation systems in Jambi province, Sumatra, Indonesia, to investigate effects of land-use change on the diversity and abundance of earthworms—a major group of soil-ecosystem engineers that often is associated with human activities. Density and biomass of earthworms increased 4—30-fold in oil palm and rubber monoculture plantations compared to rainforest. Despite much higher abundance, earthworm communities in plantations were less diverse and dominated by the peregrine morphospecies Pontoscolex corethrurus, often recorded as invasive. Considering the high deforestation rate in Indonesia, invasive earthworms are expected to dominate soil communities across the region in the near future, in lieu of native soil biodiversity. Ecologically-friendly management approaches, increasing structural habitat complexity and plant diversity, may foster beneficial effects of invasive earthworms on plant growth while mitigating negative effects on below-ground biodiversity and the functioning of the native soil animal community.

     

Unilateral Dampening of Bmp Activity by Nodal Generates Cardiac Left-Right Asymmetry

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Highlights? Cardiac laterality involves Nodal modulating an antimotogenic Bmp activity ? The Nodal target Hyaluronan synthase 2 unilaterally dampens Bmp signaling activity ? Nonmuscle myosin II is positively regulated by Bmp within cardiac tissue ? High levels of nonmuscle myosin II activity reduce cardiac cell motility     

Mutational analysis in podocin-associated hereditary nephrotic syndrome in Polish patients: founder effect in the Kashubian population

Hereditary nephrotic syndrome is caused by mutations in a number of different genes, the most common being NPHS2. The aim of the study was to identify the spectrum of NPHS2 mutations in Polish patients with the disease. A total of 141 children with steroid-resistant nephrotic syndrome (SRNS) were enrolled in the study. Mutational analysis included the entire coding sequence and intron boundaries of the NPHS2 gene. Restriction fragment length polymorphism (RFLP) and TaqMan genotyping assay were applied to detect selected NPHS2 sequence variants in 575 population-matched controls. Twenty patients (14 %) had homozygous or compound heterozygous NPHS2 mutations, the most frequent being c.1032delT found in 11 children and p.R138Q found in four patients. Carriers of the c.1032delT allele were exclusively found in the Pomeranian (Kashubian) region, suggesting a founder effect origin. The 14 % NPHS2 gene mutation detection rate is similar to that observed in other populations. The heterogeneity of mutations detected in the studied group confirms the requirement of genetic testing the entire NPHS2 coding sequence in Polish patients, with the exception of Kashubs, who should be initially screened for the c.1032delT deletion.