Met326Ile aminoacid polymorphism in the human p85 alpha gene has no major impact on early insulin signaling in type 2 diabetes.

Class I alpha phosphatidylinositol (PI) 3-kinase is an important enzyme in the early insulin signaling cascade, and plays a key role in insulin-mediated glucose transport. Despite extensive investigation, the genes responsible for the development of the common forms of type 2 diabetes remain unknown. This study was performed to identify variants in the coding region of p85 alpha, the regulatory subunit of PI 3-kinase. Fibroblasts from skin biopsies from type 2 diabetics and controls were established to address this issue. P85 alpha cDNA was sequenced, and a single point mutation at codon 326 was found. This mutation resulted in a homozygous missense amino acid change Met --> Ile in one subject with type 2 diabetes and heterozygous variant in two other diabetic patients and one with severe insulin resistance. Interestingly, those patients revealed an impaired insulin-mediated insulin receptor substrate (IRS)-1 binding to p85 alpha without any alteration in IRS-2/p85 alpha association. Furthermore, IRS-1, IRS-2, p85 alpha and MAPK protein contents were not significantly changed, and neither were MAPK or Akt phosphorylation. We conclude from our data that this variant may have only minor impact on signaling events; however, in combination with variants in other genes encoding signaling proteins, this may have a functional impact on early insulin signaling.     

Leydig cell mitoses in human testes bearing early germ cell tumors

Summary Numerous mitoses were noted in testicular tissue from adult men with early germ cell tumors. More than 15 Leydig cells undergoing mitosis were found in the interstitial compartment. The presence of specific crystalline intracytoplasmatic inclusions demonstrated for the first time that differentiated Leydig cells are capable of proliferation. Occasionally cells are difficult to discriminate during mitosis. To establish reference criteria, the light- and electron-microscopic features of the following mitotic cells were examined: Leydig cells, fibroblasts, perivascular cells, peritubular cells, and lymphocytes. Supplementary mitoses in germ cell tumors and in a case of Leydig cell tumor were investigated. In the literature, only single reports of mitoses in Leydig cells are available. The frequent incidence of Leydig cell mitosis in early germ cell tumors may be due to the presence of growth-promoting factors in the testicular tissue.     

No evidence for linkage of autosomal dominant proximal spinal muscular atrophies to chromosome 5q markers

Summary Two recent articles have reported the linkage of a gene for recessive spinal muscular atrophy (SMA) on the chromosome region 5q11.2–13.3. Our data show no linkage of the dominantly inherited forms of SMA to this chromosome region.     

Synthesis patterns of a set of follicle cell proteins in Drosophila melanogaster sibling species

The protein synthesis pattern of a set of stage and tissue specific proteins has previously been described in Drosophila melanogaster. The analysis of this set of follicle cell proteins (Fc proteins) is here extended to cover several sibling species of Drosophila melanogaster, namely D. simulans, D. mauritiana, D. erecta and D. yakuba. Even though a similar set of proteins were synthesized in these species, minor differences in size of the proteins were found between the species. Some of the species exhibited variation within species.     

Chitinase activity in the digestive tract of the cod, Gadus morhua (L.)

The study was made to determine if enzymatic degradation of chitin occurs in the digestive tract of the cod, Gadus morhua . The method employed corresponds to the end product measurement of Jeuniaux (1966), using 'native' chitin as the substrate. The following results were obtained.

• (1) 

  Chitinolytic enzyme of high activity is present in enzyme solutions from the stomach contents, gastric mucosa and intestinal contents.
• (2) 

  Lower chitinase activities are found in samples of the intestinal mucosa and the pyloric caeca.
• (3) 

  The optimum pH ranges for the action of the enzymes in the stomach and the intestine differ: 4.5–5.1 and 5.1–6.5, respectively.
• (4) 

  The role of chitin-decomposing bacteria is discussed, based on bacterial numbers and pH conditions in the digestive tract. The existence of two different enzyme systems is indicated.

     

Morphological parameters affecting false lumen thrombosis following type B aortic dissection: a systematic study based on simulations of idealized models

Type B aortic dissection (TBAD) carries a high risk of complications, particularly with a partially thrombosed or patent false lumen (FL). Therefore, uncovering the risk factors leading to FL thrombosis is crucial to identify high-risk patients. Although studies have shown that morphological parameters of the dissected aorta are related to FL thrombosis, often conflicting results have been reported. We show that recent models of thrombus evolution in combination with sensitivity analysis methods can provide valuable insights into how combinations of morphological parameters affect the prospect of FL thrombosis. Based on clinical data, an idealized geometry of a TBAD is generated and parameterized. After implementing the thrombus model in computational fluid dynamics simulations, a global sensitivity analysis for selected morphological parameters is performed. We then introduce dimensionless morphological parameters to scale the results to individual patients. The sensitivity analysis demonstrates that the most sensitive parameters influencing FL thrombosis are the FL diameter and the size and location of intimal tears. A higher risk of partial thrombosis is observed when the FL diameter is larger than the true lumen diameter. Reducing the ratio of the distal to proximal tear size increases the risk of FL patency. In summary, these parameters play a dominant role in classifying morphologies into patent, partially thrombosed, and fully thrombosed FL. In this study, we point out the predictive role of morphological parameters for FL thrombosis in TBAD and show that the results are in good agreement with available clinical studies.

     

Cloning of the amphibolic Calvin cycle/OPPP enzyme d-ribulose-5-phosphate 3-epimerase (EC 5.1.3.1) from spinach chloroplasts: functional and evolutionary aspects

Exploiting the differential expression of genes for Calvin cycle enzymes in bundle-sheath and mesophyll cells of the C4 plant Sorghum bicolor L., we isolated via subtractive hybridization a molecular probe for the Calvin cycle enzyme d-ribulose-5-phosphate 3-epimerase (R5P3E) (EC 5.1.3.1), with the help of which several full-size cDNAs were isolated from spinach. Functional identity of the encoded mature subunit was shown by R5P3E activity found in affinity-purified glutatione S-transferase fusions expressed in Escherichia coli and by three-fold increase of R5P3E activity upon induction of E. coli overexpressing the spinach subunit under the control of the bacteriophage T₇ promoter, demonstrating that we have cloned the first functional ribulose-5-phosphate 3-epimerase from any eukaryotic source. The chloroplast enzyme from spinach shares about 50% amino acid identity with its homologues from the Calvin cycle operons of the autotrophic purple bacteria Alcaligenes eutrophus and Rhodospirillum rubrum. A R5P3E-related eubacterial gene family was identified which arose through ancient duplications in prokaryotic chromosomes, three R5P3E-related genes of yet unknown function have persisted to the present within the E. coli genome. A gene phylogeny reveals that spinach R5P3E is more similar to eubacterial homologues than to the yeast sequence, suggesting a eubacterial origin for this plant nuclear gene.Abbreviations R5P3E d-ribulose-5-phosphate 3-epimerase - RPI ribose-5-phosphate isomerase - TKL transketolase - PRK phosphoribulokinase - GAPDH glyceraldehyde-3-phosphate dehydrogenase - FBP fructose-1,6-bisphophatase - FBP fructose 1,6-bisphosphate - G6PDH glucose-6-phosphate dehydrogenase - 6PGDH 6-phosphogluconate dehydrogenase - OPPP oxidative pentose phosphate pathway - Rubisco ribulose-1,5-bisphosphate carboxylase/oxygenase - FBA fructose-1,6-bisphophate aldolase - IPTG isopropyl -d-thiogalactoside - GST glutathione S-tranferase - PBS phosphate-buffered saline - TPI triosephosphate isomerase     

Zur Nahrungs?kologie des Wei?storchs (Ciconia ciconia) in Oberschwaben: Beobachtungen an zwei Paaren

Zusammenfassung Das Nahrungssuchverhalten zweier Weißstorch-Paare wurde durch systematische Beobachtung der Störche im Gelände erfaßt. Das Storchenpaar mit gutem Grünlandangebot in der Nähe des Nestes und kleiner Jungenzahl hatte während der ganzen Brutsaison viel Freizeit. Es suchte in einem Entfernungsbereich bis 1,5 km vom Nest Futter und wandte fast ausschließlich die profitable Mäusejagd an. Das Storchenpaar mit schlechtem Grünlandangebot in der Nähe des Nestes und relative großer Jungenzahl nutzte während der Jungenaufzucht einen Großteil der Helligkeitsperiode zur Futtersuche. Es dehnte dabei seinen Entfernungsbereich bis 3,8 km vom Nest aus und ging bei gutem Regenwurmangebot in nahen Entfernungen zum Nest auch der unprofitablen Regenwurmjagd nach. Die Nahrungsaufnahme der Störche betrug während der Brutphase etwa 2600 kJ, während der Aufzucht von ein bis zwei Jungen ungefähr 8850 kJ pro Storch und Tag.

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On the feeding ecology of the White stork (Ciconia ciconia) in Obserschwaben (Baden-Württemberg, Germany): observations on two pairs

Summary The foraging behaviour of two pairs of White storks was recorded by rigorous observations in the field. One pair of storks, with many meadows in the vicinity of their nest and a small clutch size, spent much time resting throughout the breeding season. They searched for food within a range of 1.5 km from the nest and used the profitable mouse hunting method almost exclusively. When rearing its young, the other pair of storks, with few meadows in the vicinity of their nest and a relatively large clutch size, used a large part of the daylight period for foraging. Thus they expanded their range up to 3.8 km from the nest. When earthworms were abundant, they also used the unprofitable earthworm hunting method within short distances from the nest. The daily energy intake per stork during incubation was approximately 2600 kJ, and approximately 8850 kJ when rearing young.