Über das Auftreten vonElminius modestus Darwin in der Elbmündung

Zusammenfassung Im Jahre 1953 wurde das Auftreten vonElminius modestus Darwin in der Elbmündung beobachtet. Der Siedlungsbereich vonElminius erstreckt sich von 0,5 unter bis 2,5 m über Tnw. Dabei tritt diese Seepocke im Bereich bis 1 m über Tnw mitBalanus balanoides und von 0,5 m über Tnw abwärts mitBalanus improvisus in Konkurrenz.Elminius ist vermutlich durch Schiffsbewuchs Mitte 1953 nach Cuxhaven gekommen.Zu besonderem Dank für ihre brieflichen Mitteilungen bin ich den Herren Dr.Crisp-Bangor, Dr.Knight-Jones-Bangor, Dr.Den Hartog-Den Helder, Dr.Engländer-Köln, Dr.Krause-Norderney und Dr.Schäfer-Wilhelmshaven verpflichtet. Herr Dr.Duncan-Waugh-Burnham on-Crouch über-ließ mir freundlicherweise Vergleichsmaterial vom River Roach-Essex.     

Effect of Penicillamine in Promoting Lead Excretion

A spectrochemical study of the urine and blood of 14 subjects exposed to lead in their work for several years, but without obvious signs of intoxication, was carried out to determine the porphyrin and lead content before and after a provocative dose of 0.9 g. penicillamine, administered on a single day.The average total urinary porphyrin excretion before administration of penicillamine was 0.506 mg. per litre (normal value = 0.274), and after penicillamine administration 0.386 mg. per litre (normal value = 0.274). The average lead excretion before administration of penicillamine was less than 0.013 mg. per litre (normal value = 0.031) and after administration of penicillamine 0.367 mg. per litre (normal value = 0.047).The average erythrocyte porphyrin content was 76.8 μg. % before and 76.95 μg. % after administration of penicillamine—values approximately thrice normal. Blood lead content before administration of penicillamine averaged 7.61 μg. % and after penicillamine 5.68 μg. %.Lead excretion in exposed persons before penicillamine administration was less than in apparently normal persons, while porphyrin levels were higher. The effect of penicillamine is shown by a definite increase in lead excretion (average = 0.406 mg. lead per gram penicillamine administered) and a decrease in porphyrin excretion in the 14 subjects.     

Increased Glucose-induced Secretion of Glucagon-like Peptide-1 in Mice Lacking the Carcinoembryonic Antigen-related Cell Adhesion Molecule 2 (CEACAM2)

Carcinoembryonic antigen-related cell adhesion molecule 2 (CEACAM2) regulates food intake as demonstrated by hyperphagia in mice with the Ceacam2 null mutation (Cc2^−/−). This study investigated whether CEACAM2 also regulates insulin secretion. Ceacam2 deletion caused an increase in β-cell secretory function, as assessed by hyperglycemic clamp analysis, without affecting insulin response. Although CEACAM2 is expressed in pancreatic islets predominantly in non-β-cells, basal plasma levels of insulin, glucagon and somatostatin, islet areas, and glucose-induced insulin secretion in pooled Cc2^−/− islets were all normal. Consistent with immunofluorescence analysis showing CEACAM2 expression in distal intestinal villi, Cc2^−/− mice exhibited a higher release of oral glucose-mediated GLP-1, an incretin that potentiates insulin secretion in response to glucose. Compared with wild type, Cc2^−/− mice also showed a higher insulin excursion during the oral glucose tolerance test. Pretreating with exendin(9–39), a GLP-1 receptor antagonist, suppressed the effect of Ceacam2 deletion on glucose-induced insulin secretion. Moreover, GLP-1 release into the medium of GLUTag enteroendocrine cells was increased with siRNA-mediated Ceacam2 down-regulation in parallel to an increase in Ca²⁺ entry through L-type voltage-dependent Ca²⁺ channels. Thus, CEACAM2 regulates insulin secretion, at least in part, by a GLP-1-mediated mechanism, independent of confounding metabolic factors.     

Calicioid lichens and fungi in amber – Tracing extant lineages back to the Paleogene

Calicioid lichens and fungi are a polyphyletic grouping of tiny ascomycetes that accumulate a persistent spore mass (mazaedium) on top of their usually well-stalked ascomata (‘mazaediate fungi’). In addition to extant forms, six fossils of the group were previously known from European Paleogene amber. Here we report nine new fossils and analyze the preserved features of all fossils to assess their applicability for dating molecular phylogenies. Many fossils are extremely well preserved, allowing detailed comparisons with modern taxa. SEM investigation reveals that even fine details of ascospore wall ultrastructure correspond to those seen in extant specimens. All fossils can confidently be assigned to modern genera: three to Calicium (Caliciaceae, Lecanoromycetes), five to Chaenotheca (Coniocybaceae, Coniocybomycetes), six to Chaenothecopsis (Mycocaliciaceae, Eurotiales), and one to Phaeocalicium (Mycocaliciaceae, Eurotiales). Several Calicium and Chaenotheca fossils are assignable to specific lineages within their genera, while the Chaenothecopsis fossils demonstrate the extent of intraspecific variation within one such lineage. Some features in the morphology of Chaenotheca succina nov. sp. seem to be ancestral as they have not been reported from modern species of the genus.     

Inactivation of the photosynthetic carbon reduction cycle in isolated mesophyll protoplasts subjected to freezing stress

Isolated mesophyll protoplasts from Valerianella locusta L. were subjected to freeze-thaw cycles. Subsequently, steady-state pool sizes of ¹⁴C-labeled intermediates of the photosynthetic carbon reduction cycle were determined by high performance liquid chromatography. Protoplasts in which CO₂ fixation was inhibited by preceding freezing stress, showed a strong increase in the proportion of fructose-1,6-bisphosphate, sedoheptulose-1,7-bisphosphate and triose phosphates. These results indicate an inhibition of the activities of stromal fructose-1,6-bisphosphatase and sedoheptulose-1,7-bisphosphatase. Furthermore, freezing stress caused a slight increase in the proportion of labeled ribulose-1,5-bisphosphate, which may be based on an inhibition or ribulose bisphosphate carboxylase activity. It was shown earlier (Rumich-Bayer and Krause 1986) that freezing-thawing readily affects photosynthetic CO₂ assimilation independently of thylakoid inactivation. The present results are interpreted in terms of an inhibition of the light-activation system of the photosynthetic carbon reduction cycle, caused by freezing stress.Abbreviations FBP Fructose-1,6-bisphosphate - HMP Hexose Monophosphates - PGA 3-phosphoglycerate - PMP Pentose Monophosphates - RBP Ribulose-1,5-bisphosphate - SBP Sedoheptulose-1,7-bisphosphate - TP Triose Phosphates     

Palladium-Mediated Hydrogenation of Unsaturated Hydrocarbons with Hydrogen Gas Released during Anaerobic Cellulose Degradation

Among five hydrogenation catalysts, palladium on charcoal was the most reactive one when suspended in anaerobic culture medium, and Lindlar catalyst (Pd on CaCO₃) was the most reactive one when suspended in the gas phase of culture tubes. Palladium on charcoal in the culture medium (40 to 200 mg 10 ml⁻¹) completely inhibited growth of Neocallimastix frontalis and partly inhibited Ruminococcus albus. Lindlar catalyst (40 to 200 mg per tube) suspended in a glass pouch above the culture medium did not affect the rate of cellulose degradation or the ratio of fermentation products by these organisms. Acetylene added to tubes containing Lindlar catalyst in pouches, and either of the two organisms in monoculture or coculture with Methanospirillum hungatei, was reduced to ethylene and then ethane, followed by hydrogen production. Similar results were obtained with 1-pentene. Neither acetylene nor 1-pentene affected cellulose degradation but both inhibited methanogenesis. In the presence of Lindlar catalyst and propylene or 1-butene, fermenter-methanogen cocultures continued to produce methane at the same rate as controls and no olefin reduction occurred. Upon addition of bromoethanesulfonic acid, methanogenesis stopped and olefin reduction took place followed by hydrogen evolution. In a gas mixture consisting of propylene, 1-butene, and 1-pentene, the olefins were reduced at rates which decreased with increasing molecular size. These results demonstrate the technical feasibility of combining in one reactor the volatile fatty acid production by anaerobic digestion with chemical catalyst-mediated reductions, using the valuable by-product hydrogen.     

Immunocytochemical identification of structures containing putative red pigment-concentrating hormone in two species of decapod crustaceans

Summary By use of an antiserum raised against the Nterminal sequence pGlu-Leu-Asn-Phe..., common to red pigment-concentrating hormone (RPCH) of Pandalus borealis and three structurally similar insect neuropeptides, putative RPCH-immunopositive structures were revealed in the eyestalks of Carcinus maenas and Orconectes limosus and in the brain and thoracic ganglion (TG) of C. maenas. In the eyestalks, complete neurosecretory pathways were demonstrated, consisting of perikarya, axons and terminals in the neurohemal organ, the sinus gland (SG). In C. maenas approximately 20 small RPCH cells are present as a distinct group adjacent to the medulla terminalis ganglionic X-organ (MTGXO, XO). They are morphologically different from the larger XO perikarya, which contain the crustacean hyperglycemic hormone (CHH). The occurrence of both neuropeptides in distinct neurosecretory pathways was ascertained by immunologic double staining (PAP/gold) or by analysis of consecutive sections. In addition, a group of two to four larger RPCH cells is located in the proximal part of the MT. In O. limosus, RPCH cells are found in the XO. Cells corresponding to the proximal MT cells of C. maenas were not found. In both species, a few more weakly staining immunopositive perikarya were observed in clusters of cell somata of the optic ganglia. It is uncertain whether these are connected to the SG.In the brain of C. maenas, several smaller and three larger perikarya were consistently observed in the dorsal lateral cell somata adjacent to the olfactory lobes. In the optic nerve, two axons that project into the eyestalk were stained. Some axons were also observed in the ventral median neuropil of the brain. In the TG, RPCH cells were found in small numbers in median positions, i.e., in clusters of somata between the ganglia of the appendages.HPLC analysis of the red pigment-concentrating activity from the SG of C. maenas revealed that the retention time of the neuropeptide is similar but not identical to that of Pandalus borealis RPCH.     

Freezing damage and frost tolerance of the photosynthetic apparatus studied with isolated mesophyll protoplasts of Valerianella locusta L.

Mesophyll protoplasts were isolated from unhardened and cold-acclimated leaves of Valerianella locusta L. and subjected to freeze-thaw treatment. To evaluate the extent and course of freezing injury, photosynthetic reactions of whole protoplasts and of free thylakoid membranes, liberated from protoplasts by osmotic lysis, were measured. In addition, the integrity of the protoplasts was determined by microscopy. The results reveal an increased frost tolerance of protoplasts isolated from acclimated leaves with respect to all parameters measured. CO₂-dependent O₂ evolution (representing net photosynthetic CO₂ fixation of protoplasts) was the most freezing-sensitive reaction; its inhibition due to freeze-thaw treatment of protoplasts was neither correlated with disintegration of the plasma membrane, nor was it initiated by inactivation of the thylakoid membranes. The frost-induced decline of protoplast integrity was not closely correlated to thylakoid damage either. Freezing injury of the thylakoid membranes was manifested by inhibition of photosynthetic electron transport and photophosphorylation. Both photosystems were affected by freezing and thawing with strongest inhibition occurring in the water-oxidation system or at the oxidizing site of photosystem II. Photophosphorylation responded more sensitively to freezing stress than electron transport, although uncoupling (increased permeability of the thylakoid membranes to protons) was not a conspicuous effect. The data are discussed in relation to freezing injury in leaves and seem to indicate that frost damage in vivo is initiated at multiple sites.Abbreviations Chl chlorphyll - DCMU 3-(3,4-dichlorophenyl)-1,1-dimethylurea - DCIP 2,6-dichlorophenolindophenol - DPC 1,5-diphenylcarbazide - Hepes 2-[4-(2-hydroxyethyl)-1-piperazinyl]-ethanesulfonic acid - MES 2-(N-morpholino)-ethanesulfonic acid - PS I photosystem I - PS II photosystem II     

Alpha 2-macroglobulin gene expression during rat development studied by in situ hybridization.

The sites of alpha 2-macroglobulin mRNA synthesis during rat development have been localized by in situ hybridization using a rat alpha 2-macroglobulin cDNA probe. Fetal liver was found to be the major site of alpha 2-macroglobulin mRNA synthesis. In addition, alpha 2-macroglobulin mRNA was detected in brain, spinal cord and eye. Alpha 2-Macroglobulin mRNA was quantitated by use of a sensitive RNAse protection assay. Maximal levels of alpha 2-macroglobulin mRNA were found in fetal livers shortly before birth. A rapid decline of alpha 2-macroglobulin mRNA occurred within 1 day after parturition. A similar time course, although at an approximately 20-fold lower level, was observed for alpha 2-macroglobulin mRNA in livers of pregnant rats. Alpha 2-Macroglobulin mRNA could also be detected in placenta. The levels were comparable to those found in maternal livers.