Genesis, goals and achievements of Long-Term Ecological Research at the global scale: A critical review of ILTER and future directions

Since its founding in 1993 the International Long-term Ecological Research Network (ILTER) has gone through pronounced development phases. The current network comprises 44 active member LTER networks representing 700 LTER Sites and ~80 LTSER Platforms across all continents, active in the fields of ecosystem, critical zone and socio-ecological research. The critical challenges and most important achievements of the initial phase have now become state-of-the-art in networking for excellent science. At the same time increasing integration, accelerating technology, networking of resources and a strong pull for more socially relevant scientific information have been modifying the mission and goals of ILTER. This article provides a critical review of ILTER's mission, goals, development and impacts. Major characteristics, tools, services, partnerships and selected examples of relative strengths relevant for advancing ILTER are presented. We elaborate on the tradeoffs between the needs of the scientific community and stakeholder expectations. The embedding of ILTER in an increasingly collaborative landscape of global environmental observation and ecological research networks and infrastructures is also reflected by developments of pioneering regional and national LTER networks such as SAEON in South Africa, CERN/CEOBEX in China, TERN in Australia or eLTER RI in Europe. The primary role of ILTER is currently seen as a mechanism to investigate ecosystem structure, function, and services in response to a wide range of environmental forcings using long-term, place-based research. We suggest four main fields of activities and advancements for the next decade through development/delivery of a: (1) Global multi-disciplinary community of researchers and research institutes; (2) Strategic global framework and strong partnerships in ecosystem observation and research; (3) Global Research Infrastructure (GRI); and (4) a scientific knowledge factory for societally relevant information on sustainable use of natural resources.

River restoration success: a question of perception

What defines success and failure of river restoration measures is a strongly debated topic in restoration science, but standardized approaches to evaluate either are still not available. The debate is usually centered on measurable parameters, which adhere to scientific objectivity. More subjective aspects, such as landscape aesthetics or recreational value, are usually left out, although they play an important role in the perception and communication of restoration success. In this paper, we show that different perceptions of restoration success exist by analyzing data from 26 river restoration measures in Germany. We addressed both objective parameters, such as hydromorphological changes and changes in fish and benthic invertebrate assemblages, from field investigations, and subjective parameters, such as opinions and perceptions, from water managers via an online survey. With regard to the objective hydromorphological and biotic parameters, our results agree with many studies that have reported improvements in the hydromorphology following restoration; however, there is no similar agreement between results concerning changes in the benthic invertebrate and fish assemblages. The objective results do not correspond to the subjective parameters because self-evaluation of the restoration projects by water managers was overly positive. Indeed, 40% of the respondents admitted that their evaluation was based on gut feeling, and only 45% of the restoration measures were monitored or occasionally checked. This lack of objectively recorded data meant that the water managers were not able to reasonably evaluate restoration success. In contrast, some self-evaluation responses reflected a different perception of the restoration success that was based on landscape aesthetic values or on benefit for the public; others adopted a general "condemned to success" attitude. Based on our data, we argue (1) that goals should be thoughtfully formulated prior to restoration implementation and (2) that it is necessary to monitor river restoration success from different perspectives.

Purification and characterization of F420H2-dehydrogenase from Methanolobus tindarius

The oxidation of F420H2 (reduced coenzyme F420) is a key reaction in the final step of methanogenesis. This step is catalyzed in Methanolobus tindarius by the membrane-bound F420H2-dehydrogenase which was purified 31-fold to apparent homogeneity. The apparent molecular mass of the native enzyme was 120 kDa. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed the presence of five different subunits of apparent molecular masses of 45 kDa, 40 kDa, 22 kDa, 18 kDa and 17 kDa. The purified F420H2-dehydrogenase, which was yellowish, contained 16 +/- 2 mol iron and 16 +/- 3 mol acid-labile sulfur/mol enzyme. No flavin could be detected. The oxygen-stable enzyme catalyzed the oxidation of F420H2 (apparent Km = 5.4 microM) with methylviologen and metronidazole as electron acceptors at a specific rate of 13 mumol.min-1.mg-1 (kcat = 25.5 s-1). The isoelectric point was at pH 5.0. The temperature optimum was at 37 degrees C and the pH optimum at 6.8.

Effects of self- and cross-reinnervation on the numbers of motoneurons regenerating to forearm muscles in young and adult rats

The present study was carried out to compare the ability of motoneurons to regenerate to functionally appropriate and inappropriate muscles, following axotomy at different stages of postnatal development. Five-, 10-, 21-day-old and adult rats of both sexes were used. In one group, the right median and radial nerves were cut and reunited. In a second group, the cut nerves were cross reunited and, in a third group the nerves were merely exposed. Following survival periods of up to one year, the extent of motoneuron regeneration through the repaired nerves was determined by injecting the retrogradely transported tracers horseradish peroxidase (HRP) and Fast Blue into the flexor and extensor muscles of the right forearm. The results were expressed in terms of the difference between the number of labelled motoneurons on the experimental side of the spinal cord and the number on the control side, the latter having been labelled by injection of HRP and Fast Blue into the muscles of the left forearm. Comparisons were then made between the groups with respect to the age at which axotomy occurred, and the target of regeneration. The results showed that when axotomy was performed in 5- and 10-day-old rats, significantly fewer motoneurons were labelled, irrespective of whether or not the target was functionally appropriate, than when axotomy was performed in adulthood. The difference was most likely due to a lower survival rate of motoneurons following axotomy in neonates. No difference was found, however, between the numbers of labelled median and radial nerve motoneurons following self- versus cross-reinnervation in any age group. This suggests that, in both adult and neonatal rats, motoneurons which survive axotomy are able to regenerate equally well to functionally appropriate or inappropriate muscles.

The influence of zinc administration on the development of experimental lung metastases after an injection of tumour cells into the tail vein of rats

Rats having received drinking water enriched with zinc (zinc acetate, 22.8 mmol/l) developed significantly more pulmonal metastases after an i.v. injection of 5 x 10(5) cultivated cells of a benzpyrene-induced sarcoma than receiving normal drinking water. Zinc ions seem to promote the emigration, implantation and outgrowth of circulating tumour cells.

Comparison of the efficiencies of true blue and diamidino yellow as retrograde tracers in the peripheral motor system

The abilities of the fluorescent retrograde tracers true blue and diamidino yellow to label motor neurons of the rat sciatic nerve were compared quantitatively. Following injection of a mixture of the 2 tracers into the sciatic nerve, diamidino yellow was found only in double-labelled neurons, while 28% of labelled neurons contained true blue alone. The relative labelling efficiency of diamidino yellow, at only 72%, was significantly lower than that of true blue. When the tracers were injected separately a difference in the labelling efficiency was still observed but, in addition, there were significantly fewer diamidino yellow-labelled neurons than when a mixture had been injected. This suggests that the presence of true blue in the mixture had enhanced the uptake, transport or visualisation of diamidino yellow. When a mixture of true blue and diamidino yellow was applied to the cut sciatic nerve, the relative labelling efficiency of diamidino yellow (77%) was again found to be lower than that of true blue, but positive identification of diamidino yellow-labelled cells was hampered by chromatolytic changes in the cell bodies. Injection of the tracer mixture into the gastrocnemius muscle resulted in a diamidino yellow labelling efficiency (36%) significantly lower than that obtained with either nerve injection or nerve dipping. Thus, compared to true blue, diamidino yellow was either less capable of reaching the motor endplates within the muscle, or it was taken up less efficiently by axon terminals than by the axons themselves.

The arrangement of forearm motoneurons in young and adult rats and the possibility of naturally occurring motoneuron death

The normal number and arrangement of motoneurons contributing fibres, via the median and radial nerves, to the forearm muscles of the rat were determined at different stages of postnatal development. Horseradish peroxidase was applied directly to the proximal cut ends of the nerves in 5, 10, 21 days old and adult rats. At each stage of development, the motoneuronal pool for each nerve was confined to the ipsilateral, dorsolateral area of Lamina IX. In general, median nerve motoneurons were found dorsal and medial to those of the radial nerve and were located between the rostral parts of the C6-T1 segments of the spinal cord. The radial nerve motoneuronal pool extended between the caudal end of the C4 and rostral tip of the T1 segment. There was considerable overlap between the two populations, especially along the dorsoventral axis. Counts of labelled motoneurons revealed that significantly fewer were present in adult compared to 5 days old rats (P less than 0.05 for each nerve). Approximately 50% of the motoneurons were lost from each nerve over this period. Although results from other studies suggest that part of the apparent loss may have been due to deficiencies in the HRP tracing technique, the possibility of motoneuronal death cannot be entirely excluded in this study.

Explanation for the labeling of cervical motoneurons in young rats following the introduction of horseradish peroxidase into the calf

This study was carried out to determine whether cervical motoneurons, labeled following the introduction of horseradish peroxidase into the rat hind leg, belong to the cutaneous trunci motoneuron pool. The cutaneous trunci is a superficial muscle that extends from the axilla, over the flank, and into the thigh. Its nerve supply is derived from the brachial plexus. In experimental animals, horseradish peroxidase was either injected directly into the right gastrocnemius muscles, or applied to gelfoam and implanted over the calf muscles in the right leg of 5-, 10-, 15-day-old and adult rats. In control animals the cutaneous trunci was denervated prior to the administration of horseradish peroxidase. Labeled cervical motoneurons were present in the 5-, 10-, and 15-day-old but not the adult experimental groups and were located within the predetermined confines of the cutaneous trunci motoneuron pool. No labeling of cervical motoneurons was observed in any of the control groups in which the cutaneous trunci muscle was denervated. The most likely explanation for the labeling of cervical motoneurons in young rats was the local diffusion of horseradish peroxidase from the calf to the thigh, where it entered the cutaneous trunci muscle and was taken up by some of its motoneurons. The absence of such labeling in adult rats was probably due to the presence of connective tissue barriers to diffusion and to the greater distance between the site of horseradish peroxidase application and the cutaneous trunci muscle, which prevented the tracer from reaching the cutaneous trunci muscle and labeling its motoneurons.

Influence of operations for stress incontinence and/or genital descensus on sexual life

A variety of operations for stress incontinence or genital descensus are performed in gynecological department. The purpose of this study was to find out whether these operations influenced the patients' sexual life. In a prospective study of 55 women, all sexually active prior to the operation, various characteristics were evaluated by interview and gynaecological examination, immediately before and 6 months after the operation. We had adviced early resumption of sexual intercourse. Postoperatively, 13 of 55 (24%) patients experienced improvement in their sexual life, 37 of 55 (67%) no change, and 5 of 55 (9%) experienced a deterioration. Improvement often resulted from cessation of urinary incontinence. Deterioration was in all 5 cases due to dyspareunia and all 5 patients underwent a posterior colporrhaphy as part of the operation. We conclude that provided the patients are well-informed the prognosis for sexual life after these operations is good. However, colpoperineoplasty in combination with anterior colporrhaphy might cause dyspareunia in some patients.

Risk factors and sib correlation in physiological neonatal jaundice

The effect of a number of explanatory variables on the degree of physiological jaundice in mature infants was evaluated by multiple regression analysis. The sampling was designed so that comparisons could be made between siblings. We found an effect of gestational age, gender, infant nutrition, ABO incompatibility and induction of labour. Taking these factors into account we still found a highly significant correlation between the peak bilirubin levels of siblings. Whether this correlation is genetically or environmentally determined is not clear.

On the diffusion of horseradish peroxidase into muscles and the "spurious" labeling of motoneurons

There is some evidence to suggest that the fascial sheaths of muscles are important in preventing the labeling of motoneurons that occurs, apparently, as a result of the diffusion of horseradish peroxidase (HRP) into the muscles. To test this possibility, Gelfoam soaked in HRP was implanted over flexor and extensor muscles in the proximal forelimb of the rat. When the fascial sheaths were damaged, labeled neurons were found in the motoneuronal pools of the exposed muscles; if intact, virtually no labeling of motoneurons was observed. These results suggest that, if intramuscular injections are to be used as a method for identifying motoneuronal pools, care should be taken when exposing the muscle to be injected, to ensure that surrounding muscles and their fascial sheaths are not damaged.

Phosphate and the development of nephrocalcinosis in rats fed diets containing alpha protein

It has been suggested that nephrocalcinosis in rats fed diets containing alkali-treated soy protein may be due to a high availability of phosphate in the diet. In the present study, the development of nephrocalcinosis in rats fed a diet containing 20% alpha protein (an alkali-treated soy protein) was compared with that in rats fed the same diet supplemented with additional phosphate. Phosphate supplementation of the alpha protein diet produced a form of nephrocalcinosis that was morphologically different, at both the light- and electronmicroscopic level, from that obtained with the unsupplemented diet but was quite similar to that obtained with a phosphate-supplemented standard commercial laboratory diet. Levels of serum and urinary calcium and phosphorus and urinary cyclic AMP suggested that a phosphate-induced secondary hyperparathyroidism was present in the rats fed either of the phosphate-supplemented diets, but not in the rats fed the unsupplemented alpha protein diet. The results of this study suggest that nephrocalcinosis in rats fed a diet containing 20% alpha protein, without additional phosphate, is not typically phosphate-induced.

The effects of parathyroidectomy on the development of nephrocalcinosis in rats fed phosphate-supplemented and unsupplemented diets containing alpha protein

The effects of parathyroidectomy (PTX) on the development of nephrocalcinosis in rats fed a diet containing alpha protein were investigated for the purpose of determining whether the nephrocalcinosis was phosphate-induced. PTX completely prevented the occurrence of nephrocalcinosis in rats fed a phosphate-supplemented commercial laboratory diet for 4 weeks. However, PTX did not completely prevent the occurrence of nephrocalcinosis in rats fed a phosphate-supplemented alpha protein diet. Several calciferous deposits were found in the inner medulla. The same was also found in rats that underwent sham operations and PTX rats fed the basal alpha protein diet. Total renal calcium and phosphorous levels in these three groups were also similar and were about twice as great as those in corresponding groups fed phosphate-supplemented and unsupplemented commercial laboratory diets. Therefore, we conclude that the nephrocalcinosis in rats fed a basal alpha protein diet is not induced by PTH or excess phosphate, but is induced by some other factor associated with the diet.

Parathyroid stimulation in phosphate-induced nephrocalcinosis

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The development of nephrocalcinosis in the rat following injections of neutral sodium phosphate

The development of nephrocalcinosis in the rat following intraperitoneal injections of various concentrations of neutral sodium phosphate (pH 7-4) was studied using histology, histochemistry, electron microscopy and quantitative techniques. Daily injections of 0-5 M phosphate consistently produced nephrocalcinosis after 6 days or more. Calcium deposits were at first confined to the basement membranes of proximal tubules; but a longer course of injections, up to 10 days, resulted in additional basement membrane calcification in the outer cortes, and outer medulla, together with intra-luminal casts, often calcified, in the outer medulla and papilla. Calcification was not found in other organs such as liver, lung, heart or aorta. Results from quantitative estimations of total kidney calcium and phosphorus suggested that it was the calcium content which was important to the initiation of nephrocalcinosis. Ultrastructural changes, suggestive of degeneration or alteration in function, were found in mitochondria of proximal tubules in experimental animals before the onset of histologically evident nephrocalcinosis. Later changes, especially to the basal part of proximal tubular cells and their basal laminae, were thought to be consequent upon the mitochondrial changes. It is suggested that the initial renal damage was caused both directly, by a toxic effect of the phosphate load on the kidney and, indirectly, by stimulation of the parathyroid glands as a result of the hypocalcaemia and hyperphosphataemia which followed an injection of phosphate. Daily doses of 1 M phosphate for 3 days produced a type of nephrocalcinosis which was more typical of that reported by previous investigators, who used high doses of phosphate. Twice daily injections of 0-25 M phosphate for 6 days did not induce nephrocalcinosis, whereas 0-375 M phosphate given twice daily for 6 days produced only minimal calcium deposits compared with animals given 0-5 M phosphate once daily for the same period. This may have important clinical implications, since phosphate has been used to control hypercalcaemia of various etiologies.

Evaluation of dimethylhydrazine induced tumours in mice as a model system for colorectal cancer

The evolution and structure of adenomatous polyps and adenocarcinomata of the colon in NMRI mice induced by dimethylhydrazine are described. Severe toxic reactions in the liver and other organs are produced by dimethylhydrazine (DMH), but tumours are induced only in the colon and around the anus. The 100% incidence and growth characteristics of the tumours make it potentially a good model system, but investigators should take into account the widespread nonspecific cellular injury induced by this carcinogen.