Binding of soluble fibronectin and its subsequent incorporation into the extracellular matrix by early and late passage human skin fibroblasts

The specific binding of soluble 125I-labeled human plasma fibronectin (125I-HFN-P) to confluent cultures of early and late passage human skin fibroblasts was investigated. Previous studies of HFN-P bound to fibroblast cell layers indicated that HFN-P was present in the cultures in two separate pools, distinguishable on the basis of their solubility in 1% deoxycholate. Pool I contained deoxycholate-soluble fibronectin (cell-associated), whereas Pool II contained deoxycholate-insoluble fibronectin (matrix-associated). Time course studies indicated that HFN-P was initially incorporated into Pool I and then accumulated into Pool II (McKeown-Longo, P.J., and Mosher, D.F. (1983) J. Cell Biol. 97, 466-472). Examination of the kinetics of 125I-HFN-P binding to Pool I of early and late passage cultures revealed that both cultures required 2-4 h to approach steady-state conditions. Other kinetic studies showed that the rates of loss of 125I-HFN-P from either Pool I or Pool II were similar for both cultures. However, the late passage cultures bound greater than twice as much fibronectin into Pool I, per cell, than the early passage cultures. This difference was not related to a difference in the level of endogenously produced fibronectins accumulating in the medium. Late passage cultures incorporated 125I-HFN-P into the deoxycholate-insoluble Pool at an average rate 2.6 times greater than early passage cultures. The late passage cultures also chased a greater percent of their Pool I-bound fibronectin into Pool II and a lower percent into the chase medium. These results indicate that early and late passage cultures of human fibroblasts exhibit differences in the binding of soluble fibronectin and in the extent to which they incorporate soluble fibronectin into the extracellular matrix.     

Basolateral amino acid transport systems in the perfused exocrine pancreas: sodium-dependency and kinetic interactions between influx and efflux mechanisms

Basolateral amino acid transport systems have been characterized in the perfused exocrine pancreas using a high-resolution paired-tracer dilution technique. Significant epithelial uptakes were measured for L-alanine, L-serine, alpha-methylaminoisobutyric acid, glycine, methionine, leucine, phenylalanine, tyrosine and L-arginine, whereas L-tryptophan and L-aspartate had low uptakes. alpha-Methylaminoisobutyric acid transport was highly sodium dependent (81 +/- 3%), while uptake of L-serine, L-leucine and L-phenylalanine was relatively insensitive to perfusion with a sodium-free solution. Cross-inhibition experiments of L-alanine and L-phenylalanine transport by twelve unlabelled amino acids indicated overlapping specificities. Unidirectional L-phenylalanine transport was saturable (Kt = 16 +/- 1 mM, Vmax = 12.3 +/- 0.4 mumol/min per g), and weighted non-linear regression analysis indicated that influx was best described by a single Michaelis-Menten equation. The Vmax/Kt ratio (0.75) for L-phenylalanine remained unchanged in the presence of 10 mM L-serine. Although extremely difficult to fit, L-serine transport appeared to be mediated by two saturable carriers (Kt1 = 5.2 mM, Vmax1 = 7.56 mumol/min per g; Kt2 = 32.8 mM, Vmax2 = 22.9 mumol/min per g). In the presence of 10 mM L-phenylalanine the Vmax/Kt ratio for the two L-serine carriers was reduced, respectively, by 79% and 50%. Efflux of transported L-[3H]phenylalanine or L-[3H]serine was accelerated by increasing perfusate concentrations of, respectively, L-phenylalanine and L-serine, and trans-stimulated by other amino acids. In the pancreas neutral amino acid transport appears to be mediated by Na+-dependent Systems A and ASC, the classical Na+-independent System L and another Na+-independent System asc recently identified in erythrocytes. The interactions in amino acid influx and efflux may provide one of the mechanisms by which the supply of extracellular amino acids for pancreatic protein synthesis is regulated.     

M?ssbauer spectroscopic studies of the cores of human, limpet and bacterial ferritins

Ferritin cores from human spleen, limpet (Patella vulgata) haemolymph and bacterial (Pseudomonas aeruginosa) cells have been investigated using 57Fe M?ssbauer spectroscopy. The M?ssbauer spectra were recorded over a range of temperatures from 1.3 to 78 K, all the spectra are quadrupole-split doublets with similar quadrupole splittings and isomer shifts, characteristic of iron(III), while at sufficiently low temperatures the spectra of all the samples show well-resolved magnetic splitting. At intermediate temperatures, the spectra from the human ferritin exhibit typical superparamagnetic behaviour, while those from the bacterial ferritin show behaviour corresponding to a transition from a magnetically ordered to a paramagnetic state. The spectra from the limpet ferritin show a complex combination of the two effects. The results are discussed in terms of the magnetic behaviour of small particles. The data are consistent with magnetic ordering temperatures of about 3 and 30 K for the bacterial and limpet ferritin cores, respectively, while the data indicate that the magnetic ordering temperature for the human ferritin cores must be above 50 K. These differences are interpreted as being related to different densities of iron in the cores and to variations in the composition of the cores. The human ferritin cores are observed to have a mean superparamagnetic blocking temperature of about 40 K, while that of the limpet ferritin cores is about 25 K. This difference is interpreted as being due not only to different mean numbers of iron atoms in the two types of core but also to the higher degree of crystallinity in the cores of the human ferritin.     

Genetic Analysis of a Mouse t Complex Locus That Is Homologous to a Kidney Cdna Clone

A mouse kidney cDNA clone, pMK174, identifies restriction fragment length polymorphisms (RFLPs) that map to two unlinked loci. One, designated D17Rp17, has been mapped near quaking, (qk), on chromosome 17 using three sets of recombinant inbred (RI) strains. A study of several t haplotypes resulted in the identification of t-specific alleles of D17Rp17 that map to the proximal half of the t complex. Neither t-specific nor wild-type D17Rp17 alleles are present in chromosomes carrying either the T Orleans (TtOrl) or the T hairpin tail (Thp) deletions. Comparison with other molecular markers indicates that pMK174 identifies a new proximal t complex locus, Rp17. The second locus identified by pMK174, termed D4Rp18, is tentatively assigned to chromosome 4 by mouse-Chinese hamster somatic cell hybrid analysis.     

Spontaneous interstitial nephritis in kdkd mice. II. Characterization of a tubular antigen-specific, H-2K-restricted Lyt-2+ effector T cell that mediates destructive tubulointerstitial injury

In this report, we have examined the effector T cell repertoire in the spontaneous interstitial nephritis of kdkd mice. Lymph node cells from nephritic kdkd mice are capable of transferring this disease into thymectomized, irradiated, and bone marrow-reconstituted CBA/Ca recipients. CBA/Ca mice do not spontaneously develop interstitial nephritis and are normally resistant to the adoptive transfer of nephritic cells, a resistance that in the short term can be attenuated with low-dose cyclophosphamide. We therefore used delayed-type hypersensitivity responses and direct transfer of immune cells under the renal capsule to characterize nephritogenic effector cells from kdkd donor mice. Lyt-2+, L3T4- T cells from the peripheral lymphoid organs of nephritic kdkd mice, after adoptive transfer into cyclophosphamide-pretreated CBA/Ca recipients, mediate an antigen-specific delayed-type hypersensitivity response to renal tubular basement membrane antigens. These cells are restricted by gene products in H-2Kk; they are also present in nephritic, but not in control kidneys. We have also observed this same phenotypic subpopulation of kdkd lymphocytes mediate a destructive interstitial renal lesion within 7 days of being placed under the kidney capsule of CBA/Ca mice. These findings suggest that T lymphocytes reactive to a parenchymal tubular antigen are of substantial importance in the development of spontaneous interstitial nephritis in kdkd mice.     

Habitatwahl beim Neunt?terLanius collurio

Zusammenfassung Im Bereich des Meßtischblattes Bad Wildungen (MTB 4820; grundlegende DatenMann 1983,Lübcke &Mann 1984) bevorzugt der Neuntöter Viehweiden (Abb. 3). Reviere an Viehweiden zeigen eine längere kontinuierliche Besetzungszeit (Abb. 4) im Vergleich zu anderen Nutzungsformen. Die Anzahl flügger Jungvögel ist in Viehweiderevieren größer im Gegensatz zu Revieren an Mähwiesen oder Brachflächen (Abb. 5). Dieser Unterschied des Reproduktionserfolges liegt nicht an unterschiedlichen Nahrungsdichten (Abb. 6), sondern an der besseren Zugänglichkeit.

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Habitat selection in the Red-backed ShrikeLanius collurio

Summary In the area of Bad Wildungen (FRG; Hessia; MTB 4820; basic data inMann 1983,Lübcke &Mann 1984) the Red-backed Shrike selects for pastures (Abb. 3). Territories at pastures show a longer continual occupation in comparison to other land use systems (Abb. 4). The number of fledgelings is higher at pastures in comparison to meadows or fallow land (Abb. 5). This difference is not caused by higher insect densities (Abb. 6) but by better accessible prey due to permanent low vegetation at pastures.

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Reihenfolge alphabetisch und umgekehrt proportional zur geleisteten Arbeit: R. B. Auswertung, W. L. & W. M. Kartierung, W. M. Brut- und Nahrungsbiologie. Sonderdruckanforderungen an R. B.     

Environmentally-induced fluctuations in year-class strength and their implications for management

Data for river populations of common freshwater species including dace, chub, roach, gudgeon and pike are examined to assess the magnitude of natural density-independent fluctuations in the strength of year-classes. Both in the cyprinid populations and in those of some salmonids, only occasional years give rise to large cohorts of adult fish. Correlations with temperature indicate that for the cyprinid populations these are often years when temperatures are high. In the River Frome, Dorset there is a significant relationship between the growth of O-group dace and subsequent year-class strength. Faster-growing larvae may be better able to avoid predation. Both the habitat and feeding requirements of these young fish are different from those of the adults. A practical approach to improving recruitment in a population of a given species would be to first characterize, and then increase, the availability of suitable habitats and food organisms for the larval stages.     

A pike management strategy for a trout fishery

The efficiency of pike removal from a chalkstream trout fishery, by an angling society using electrofishing, was estimated over five successive autumns using mark-recapture methods. It averaged c . 50% for pike aged 1+ years or more. Numbers of 3+ and older pike decreased from 3.7 ha^-1 (1980) to 1.4 ha^-1 (1984), but there was no corresponding reduction in recruitment success. Both pike immigration and an inverse relationship between natural and fishing mortality could have reduced the effect of the pike culls. The mean weight of 0+ pike increased from 19.4 g to 48.2 g over the 5 years, but there was no change in the growth rates of older pike. Only the larger pike were able to eat the larger trout stocked, and the reduction in numbers of 3 + and older pike appears to have reduced the predation pressure on the trout population. Angling effort increased more than three-fold over the 5 years studied and rod-catches more than doubled, but catch-per-unit-effort was extremely variable between years. The increased rod catch occurred despite the decrease in numbers of large (> 33 cm) trout stocked in the spring and early summer. Compared with pre-cull years, the angling society saved about ş850 (present day prices) by stocking fewer trout.     

Murine interstitial nephritis. III. The selection of phenotypic (Lyt and L3T4) and idiotypic (RE-Id) T cell preferences by genes in Igh-1 and H-2K characterizes the cell-mediated potential for disease expression: susceptible mice provide a unique effector T cell repertoire in response to tubular antigen

The effector T cell repertoire in experimental interstitial nephritis was examined in a variety of susceptible and nonsusceptible mice. We observed that L3T4+ effector T cells in disease-susceptible mice disappear soon after immunization in preference to the emergence of Lyt-2+ effector cells. These latter cells respond with delayed-type hypersensitivity to tubular antigen in the context of H-2K. Such cells also express idiotypes (RE-Id) shared with kidney-bound alpha TBM-Ab that are regulated by an interactional effect of genes in Igh-1 and H-2K. These Lyt-2+ effector cells can be removed from renal infiltrates, and the transfer of similar cells under the renal capsule of naive mice results, within 5 days, in local interstitial nephritis. Nonsusceptible mice, however, not having these immune response genes, produce either L3T4+, Lyt-1+, RE-Id- effector T cells, which only respond to tubular antigen in the context of I-A, or Lyt-2+, RE-Id- T cells, which may lack very fine specificity. These findings suggest that susceptible mice carry a unique set of immune response genes that promote a T cell selection process that operates after induction, during the differentiation and development of disease-producing effector T cells.