Hummer. Fredningsområde som avelsbank? : Havskräfta. Mundelarnas byggnad: Stora kräftdjur. Födointag genom filtrering: Havskräfta. Bohålsräkning från ytan

Har ett hummerfredningområde någon betydelse som avelsbank? Av Mats Ulmestrand, Havsfiskelaboratoriet, Lysekil  Since 1989 a lobster (Homarus gammarus) fishing area of 1.05 km2 was closed and protected from all fishery except experimental fishery carried out by the Institute of Marine Research in Lysekil. All caught lobster were tagged and released in the area again. This paper gives an estimation of the change in egg production while the fishing mortality on H. gammarus stops. Mundelarnas funktionella morfologi hos havskräfta. Av Anders Sellbom  The Norway lobster (Nephrops norvegicus ) can be a suspension feeder, and the lobster use its mouth parts as a "landing-net". A feeding current was produced by the exopodite of the third maxillipeds and with the pleopods. This paper describes the morphology of the mouthparts with respect to suspension feeding. The activity of the mouthparts were tested during aquaria experiments. Crushed shrimps (Pandalus borealis) and nauplii of brine shrimps (Artemia salina) were used asprey. All mouthparts of N. norvegicus are covered with setae in different lenght and size. There are also different shapes among them. In general speaking there are long, serrate setae on the anteriormouthparts and short, stiff setae on the inner mouthparts. Food particles are trapped on the long, serrated setae on the outer mouthparts (mostly the third maxillipeds) and are transported by combing movements of the inner mouthparts to oesophagus. There was no significant difference in beatspeed of the exopodites. Three different sources were tested against each other: food (crushed shrimp or nauplii of brine shrimp), treatment (before, under and after addition of food) and the interaction food/treatment. Very large variance differences occurred within the same food group when tested for the interaction food/treatment. The explanation is that the exopodites do not beat simultanously and there are large speed differences between left and right exopodite. A two factor ANOVA analysis of variance was used as a statistic method. Olika aspekter på suspensionsätning hos tre decapodarter från svenska västkusten av Daniel Valentinsson, Havsfiskelaboratoriet, Lysekil Suspension feeding in adults of the edible crab Cancer pagurus (118-295 g) and the squatlobster Galathea strigosa (22-29 g) was tested in experiments offering planktonic food items of about 600 mm size measuring the clearing capacity. Both species were found to significantly clear the water of food particles comprising nauplii of the brine shrimp Artemia salina. Food intake was verified with stomach analysis. In another experiment it was investigated if the ability to suspension feed is different between the sexes in the Norway lobster Nephrops norvégiens, and if the clearance rate is dependent on the concentration of food items. No difference between the sexes was found. Neither was any difference in clearance rate depending on the food concentration found. The significance of the ability to suspension feed in larger decapods is discussed regarding the species ecological roles

Hummer. Fredningsområde som avelsbank? : Havskräfta. Mundelarnas byggnad: Stora kräftdjur. Födointag genom filtrering: Havskräfta. Bohålsräkning från ytan

Har ett hummerfredningområde någon betydelse som avelsbank? Av Mats Ulmestrand, Havsfiskelaboratoriet, Lysekil  Since 1989 a lobster (Homarus gammarus) fishing area of 1.05 km2 was closed and protected from all fishery except experimental fishery carried out by the Institute of Marine Research in Lysekil. All caught lobster were tagged and released in the area again. This paper gives an estimation of the change in egg production while the fishing mortality on H. gammarus stops. Mundelarnas funktionella morfologi hos havskräfta. Av Anders Sellbom  The Norway lobster (Nephrops norvegicus ) can be a suspension feeder, and the lobster use its mouth parts as a "landing-net". A feeding current was produced by the exopodite of the third maxillipeds and with the pleopods. This paper describes the morphology of the mouthparts with respect to suspension feeding. The activity of the mouthparts were tested during aquaria experiments. Crushed shrimps (Pandalus borealis) and nauplii of brine shrimps (Artemia salina) were used asprey. All mouthparts of N. norvegicus are covered with setae in different lenght and size. There are also different shapes among them. In general speaking there are long, serrate setae on the anteriormouthparts and short, stiff setae on the inner mouthparts. Food particles are trapped on the long, serrated setae on the outer mouthparts (mostly the third maxillipeds) and are transported by combing movements of the inner mouthparts to oesophagus. There was no significant difference in beatspeed of the exopodites. Three different sources were tested against each other: food (crushed shrimp or nauplii of brine shrimp), treatment (before, under and after addition of food) and the interaction food/treatment. Very large variance differences occurred within the same food group when tested for the interaction food/treatment. The explanation is that the exopodites do not beat simultanously and there are large speed differences between left and right exopodite. A two factor ANOVA analysis of variance was used as a statistic method. Olika aspekter på suspensionsätning hos tre decapodarter från svenska västkusten av Daniel Valentinsson, Havsfiskelaboratoriet, Lysekil Suspension feeding in adults of the edible crab Cancer pagurus (118-295 g) and the squatlobster Galathea strigosa (22-29 g) was tested in experiments offering planktonic food items of about 600 mm size measuring the clearing capacity. Both species were found to significantly clear the water of food particles comprising nauplii of the brine shrimp Artemia salina. Food intake was verified with stomach analysis. In another experiment it was investigated if the ability to suspension feed is different between the sexes in the Norway lobster Nephrops norvégiens, and if the clearance rate is dependent on the concentration of food items. No difference between the sexes was found. Neither was any difference in clearance rate depending on the food concentration found. The significance of the ability to suspension feed in larger decapods is discussed regarding the species ecological roles

An in vitro study of blood compatibility of vascular grafts made of bacterial cellulose in comparison with conventionally-used graft materials

In this study we analyzed the blood compatibility of bacterial cellulose (BC) as a new biosynthetic material for use as a vascular graft. As reference materials we used expanded polytetrafluoroethylene (ePTFE) and poly(ethylene terephthalate) (PET) vascular grafts. These materials are in clinical use today. Tubes with inner diameters of both 4 (not PET) and 6 mm were tested. Heparin-coated PVC tubes (hepPVC) were used as a negative control. Platelet consumption and thrombin-antithrombin complex (TAT) were used as parameters of coagulation and for complement activation, sC3a and sC5b-9 were used. The investigated parameters were measured after 1-h exposure to freshly drawn human blood supplemented with a low dose of heparin in a Chandler loop system. The results showed that BC exhibits no significant difference in platelet consumption, as compared with PET (6 mm), ePTFE and hepPVC. The PET material consumed more platelets than any of the other materials. The TAT generation for 4 mm tubes was not significantly different between BC and the other materials. For 6 mm tubes, however, differences were observed between hepPVC and PET (p < 0.0001); BC and hepPVC (p = 0.0016); ePTFE and PET (p < 0.0001); BC and ePTFE (p = 0.0029); BC and PET (p = 0.0141). Surprisingly, considering the low platelet consumption, the complement activation parameters (sC3a and sC5b-9) were much higher for BC, as compared with the other materials for both 4 and 6 mm tubes

Mechanical characterization of bacterial cellulose tubes for vascular tissue engineering

[No abstract available

Bacterial cellulose as a potential vascular graft: Mechanical characterization and constitutive model development.

Bacterial cellulose (BC) is a polysaccharide produced by Acetobacter Xylinum bacteria with interesting properties for arterial grafting and vascular tissue engineering including high-burst pressure, high-water content, high crystallinity, and an ultrafine highly pure fibrous structure similar to that of collagen. Given that compliance mismatch is one of the main factors contributing to the development of intimal hyperplasia in vascular replacement conduits, an in depth investigation of support mechanical properties of BC is required to further supporting its use in cardiovascular-grafting applications. The aim of this study was to mechanically characterize BC and also study its potential to accommodate vascular cells. To achieve these aims, inflation tests and uniaxial tensile tests were carried out on BC samples. In addition, dynamic compliance tests were conducted on BC tubes, and the results were compared to that of arteries, saphenous vein, expanded polytetrafluoroethylene, and Dacron grafts. BC tubes exhibited a compliance response similar to human saphenous vein with a mean compliance value of 4.27 × 10(-2) % per millimeter of mercury over the pressure range of 30-120 mmHg. In addition, bovine smooth muscle cells and endothelial cells were cultured on BC samples, and histology and fluorescent imaging analysis were carried out showing good adherence and biocompatibility. Finally, a method to predict the mechanical behavior of BC grafts in situ was established, whereby a constitutive model for BC was determined and used to model the BC tubes under inflation using finite element analysis

Bloodcompatibility studies of bacterial cellulose, a new biosynthetic vascular graft material

[No abstract available