Linking prey composition of haddock Melanogrammus aeglefinus to benthic prey availability in three different areas of the northern North Sea.

The feeding strategy and prey selection of haddock Melanogrammus aeglefinus related to the benthic infauna in the field were investigated in three different study areas (boxes) in the northern North Sea in 2007. The stomach contents of M. aeglefinus were dominated by invertebrates in all three boxes, mainly echinoderms and polychaetes, similar to the benthic communities in the field. Prey densities in the field significantly determined prey selection and, thus the feeding strategy of M. aeglefinus appeared highly opportunistic. Other prey characteristics, such as the position in the sediment or its palatability, had no significant effect on the selection process although trends were apparent that tubicolous polychaetes of the family spionids, especially Spiophanes kröyeri and Spiophanes bombyx as well as the tentaculate Phoronis spp., were not consumed and potentially avoided due to their ability to withdraw below the feeding depths or due to chemical deterrents. High abundances of echinoderm species with hard calcareous shells in the M. aeglefinus stomachs, such as the ophiurid Ophiocten affinis and the echinoid Echinocyamus pusillus, indicated their use as grinding elements. A gradual shift from benthos to fish feeding with increasing M. aeglefinus size was not found.

[Rate of reopening of macular holes following cataract operation]. / Wiedereröffnungsrate von Makulaforamina nach Kataraktoperation.

BACKGROUND: We set up this retrospective study to examine how different the functional and morphological results are following pars plana vitrectomy (ppV) for idiopathic macular holes in phakic eyes with later cataract surgery and in pseudophakic eyes, and to what extent cataract surgery can induce reopening of idiopathic macular holes after ppV. METHODS: A total of 189 eyes were vitrectomized because of idiopathic macular hole (37 pseudophakic, 152 phakic); 120 (22 pseudophakic, 98 phakic) of these eyes were examined at follow-up of an average of 19 months after vitrectomy. Cataract surgery was performed in 65 of the phakic eyes in this period. The functional and morphological results recorded for these 22 pseudophakic and 65 phakic eyes were evaluated. RESULTS: In the pseudophakic eyes preoperative visual acuity was 0.14, increasing to 0.20 postoperatively (p=0.16); in 1 case (4.5%) the macular hole was not closed at the time of the follow-up examination. Cataract extraction was performed in 65 of the phakic eyes an average of 10 months after ppV. The initial VA was 0.19 before ppV and increased to 0.37 (p<0.01) after cataract surgery; in 4 cases (6.2%) the macular hole was not closed by the time of the follow-up examination, but in each case this had already been noted when the cataract extraction was done. Reopening did not occur after cataract extraction in any of these cases. CONCLUSION: With a rate of 5.7% for reopening or persistence of macular holes, our results are comparable to those recorded in other studies. Cataract surgery following ppV does not influence the reopening rate of macular holes.

[Anatomical and functional results after elective macular surgery]. / Anatomische und funktionelle Ergebnisse nach elektiver Makulachirurgie.

PURPOSE: The purpose of this paper is to assess the anatomical and functional results after macular surgery in a large group of patients. METHODS: Between June 1995 and December 2001, 381 eyes underwent vitreous surgery for macular pucker (n=244) or macular holes (n=137) with a standard pars plana vitrectomy (PPV) with induction of posterior vitreous separation, membrane peeling, peeling of the internal limiting membrane (no ICG staining was used), and gas instillation (SF(6)). RESULTS: A second surgical intervention due to vision-threatening complications after PPV had to be performed in 8 of 381=2.1%. In the macular pucker group, metamorphopsias improved in 46.6% and the median of visual acuity (VA) improved from preoperative 0.3 to postoperative 0.5. Hole closure of macular holes was obtained in 92.2%; the median of VA improved in this group from preoperative 0.2 to postoperative 0.4. CONCLUSION: In our group a second vitreoretinal procedure due to vision-threatening complications had to be performed in 2.1%. Compared to the spontaneous course, PPV for macular pucker or macular hole has a very positive influence on functional parameters.

[Vitreoretinal secondary procedures following elective macular surgery]. / Vitreoretinale Zweiteingriffe nach elektiver Makulachirurgie.

OBJECTIVE: The spectrum of reoperations after macular surgery was investigated retrospectively in a large group of patients. All secondary surgical procedures except for cataract surgery were considered. METHODS: Between July 1995 and June 2001 353 eyes underwent macular surgery (218 due to macular pucker, 135 due to macular hole) with a pars-plana vitrectomy (PPV), creation of vitreous detachment, membrane peeling and SF(6)/air-instillation. The vitrectomies were performed by 4 different surgeons. In all patients a preoperative circular peripheral cryoretinopexy was performed 3-4 weeks before macular surgery. The follow-up was 20.9 months on average. The number of revitrectomies as well as the postoperative retinal detachment rate were investigated. RESULTS: In 33 cases (9.3%) a second vitrectomy had to be performed due to an unsatisfying postoperative macular finding: 17/218 (7.8%) after macular pucker surgery with a recurrent pucker and 16/135 (11.8%) after macular hole surgery with persistent or recurrent macular hole. In 7/353 (2.0%) a postoperative rhegmatogenous retinal detachment was observed and in 2/353 (0.6%) a postoperative endophthalmitis had to be treated. CONCLUSION: In 9.3% of our patients a second PPV due to an unsatisfying macular finding became necessary. The rate of postoperative retinal detachment of 2.0% is considerably lower than in most other studies. Therefore, a possible prophylactic effect of the preoperative circular peripheral cryoretinopexy is suggested to reduce the risk of postoperative retinal detachment.

Isolation and immunocytochemical location of the nitrite-oxidizing system in nitrospira moscoviensis

A membrane-associated nitrite-oxidizing system of Nitrospira moscoviensis was isolated from heat-treated membranes. The four major proteins of the enzyme fraction had apparent molecular masses of 130, 62, 46, and 29 kDa, respectively. The nitrite-oxidizing activity was dependent on the presence of molybdenum. In contrast to the nitrite oxidoreductase of Nitrobacter hamburgensis X14, the activity of the nitrite-oxidizing system of Ns. moscoviensis increased when solubilized by heat treatment. Electron microscopy of the purified enzyme revealed uniform particles with a size of approximately 7 x 9 nm. SDS-immunoblotting analysis of crude extracts showed that the monoclonal antibodies Hyb 153-3, which recognize the beta-subunit of the nitrite oxidoreductase from Nitrobacter, reacted with a protein of 50 kDa in Ns. moscoviensis. This protein corresponded to the protein of 46 kDa of the purified enzyme and contained a b-type cytochrome. Using electron microscopic immunocytochemistry and the monoclonal antibodies Hyb 153-3, the nitrite-oxidizing system of Ns. moscoviensis was shown to be located in the periplasmic space. Here a periodic arrangement of membrane-associated particles was found on the outside of the cytoplasmic membrane in the form of a hexagonal pattern. It is supposed that these particles represent the nitrite-oxidizing system in Nitrospira.

A new obligately chemolithoautotrophic, nitrite-oxidizing bacterium, Nitrospira moscoviensis sp. nov. and its phylogenetic relationship.

A gram-negative, non-motile, non-marine, nitrite-oxidizing bacterium was isolated from an enrichment culture initiated with a sample from a partially corroded area of an iron pipe of a heating system in Moscow, Russia. The cells were 0.9-2.2 microns x 0.2-0.4 microns in size. They were helical- to vibroid-shaped and often formed spirals with up to three turns 0.8-1.0 micron in width. The organism possessed an enlarged periplasmic space and lacked intracytoplasmic membranes and carboxysomes. The cells tended to excrete extracellular polymers, forming aggregates. The bacterium grew optimally at 39 degrees C and pH 7.6-8.0 in a mineral medium with nitrite as sole energy source and carbon dioxide as sole carbon source. The optimal nitrite concentration was 0.35 mM. Nitrite was oxidized to nitrate stoichiometrically. The doubling time was 12 h in a mineral medium with 7.5 mM nitrite. The cell yield was low; only 0.9 mg protein/l was formed during oxidation of 7.5 mM nitrite. Under anoxic conditions, hydrogen was used as electron donor with nitrate as electron acceptor. Organic matter (yeast extract, meat extract, peptone) supported neither mixotrophic nor heterotrophic growth. At concentrations as low as 0.75 g organic matter/l or higher, growth of nitrite-oxidizing cells was inhibited. The cells contained cytochromes of the b- and c-type. The G+C content of DNA was 56.9 +/- 0.4 mol%. The chemolithoautotrophic nitrite-oxidizer differed from the terrestrial members of the genus Nitrobacter with regard to morphology and substrate range and equaled Nitrospira marina in both characteristics. The isolated bacterium is designated as a new species of the genus Nitrospira.(ABSTRACT TRUNCATED AT 250 WORDS)