Morphological correlates of follicular fluid stimulation of steroidogenesis in immature porcine granulosa cells

Factors in porcine ovarian follicular fluid are known to influence steroidogenesis in cultured ovarian granulosa cells. This study examined whether ultrastructural changes characteristic of normal maturation and/or atresia accompany the steroidogenic alterations. Two and 5 day incubations of immature porcine granulosa cells were performed in media supplemented with either serum or follicular fluids (FFL) from mature follicles. Under these conditions both oestrogen and progesterone secretion were stimulated in FFL supplemented cultures as compared to serum supplemented cultures. Cells in serum exhibited increased size, number and volume of lysosomes and resembled in vivo atretic cells. In comparison, the FFL treated cells had greatly increased steroid output, numerous microvilli and increased size, number and volume of electron dense lipid droplets after 2 days of culture although the differences declined by day 5 of culture. This suggests that mature FFL contains a factor(s) stimulating granulosa maturation while inhibiting ultrastructural correlates of follicular atresia.     

The anatomy of tissue cultured red raspberry prior to and after transfer to soil

The leaf, petiole, stem and root anatomy of an aseptically cultured red raspberry clone (Rubus idaeus L.) was studied before and 5 weeks after transfer to soil under controlled environmental conditions. Tissues persistent from culture showed little or no change with time in soil; they grew minimally and slight secondary wall deposition occurred. New organs formed in successive weeks after transplantation showed a graded increase in potential size and development. Some features, such as collenchyma formation, rapidly returned to control levels; this was seen in new leaves expanding in the first week after transplantation. Other features, such as sclerenchyma formation, did not occur in leaves expanding during the first 2 weeks after transplantation, even when these were a month or more in age. Some sclerenchyma was seen in leaves expanding in the third week after transplantation, increasing in later-formed leaves. Increasing the light intensity of transplant accelerated the return to control-type organ size and appearance. During acclimatization transitional forms of leaves, petioles, stems and roots develop that ranged anatomically from culture-to control-type. This trend is analagous to the normal developmental sequence of organ formation as it affects the potential for development of successily formed organs.     

Interspecies hydrogen transfer in anaerobic degradation of CMC to CH4 by a triculture of marine bacteria

Summary Study of CMC fermentation by a marine syntrophic association of an anaerobic cellulose-degrader, a carbohydrate-fermenter, and a methanogen. Altered fermentation pattern in general agreement with the concept of interspecies hydrogen transfer was obtained only with pregrowth of methanogen followed by inoculation of the two fermentative bacteria.     

Isovolumetric and isobaric rabbit tracheal contraction in vitro

Isovolumetric and isobaric tracheal smooth muscle (TSM) contraction were studied in vitro in a preparation of the whole rabbit trachea. Eight tracheae from New Zealand White rabbits were excised and mounted at a fixed length in an organ bath. Electrical field stimulation (EFS) was performed in isovolumetric and isobaric conditions at varying transmural pressures (TMP). Supramaximal stimulation with methacholine was done at 0 TMP. Active change in pressure (delta P) with EFS showed a peak at 3.1 +/- 1.06 cmH2O TMP during inflation and at 4.1 +/- 1.18 cmH2O TMP during deflation (mean +/- SE). Active delta P decreased at higher or lower TMP. Active change in volume with EFS showed a peak at 3.2 +/- 1.26 cmH2O TMP during inflation and at 1.8 +/- 0.98 cmH2O TMP during deflation. A decrease in response was also observed at higher and lower TMP. From these data, we concluded that TSM is at optimal length (Lmax) at TMP of 2-3 cmH2O. Maximal TSM shortening with supramaximal stimulation with methacholine was 32% Lmax. This figure is considerably smaller than the 80% shortening found in unloaded strips of TSM. We conclude that rabbit TSM length is close to Lmax at TMP similar to those found at functional residual capacity and that the loads that the muscle has to overcome probably contribute to the limited shortening observed in situ.     

Biochemical significance of enhanced activity of fluorinated 1,25-dihydroxyvitamin D3 in human cultured cell lines

Several human cancer cells possess receptors for 1,25-dihydroxyvitamin D3[1,25-(OH)2D3]. In these cells 1,25-(OH)2D3 has a biphasic concentration-dependent regulatory effect on cell replication and specifically induces its own metabolism. We have studied the effects on these parameters of the native hormone together with those of two analogues fluorinated at the 24-carbon and of 1,24R,25-trihydroxyvitamin D3[1,24R,25-(OH)3D3]. The difluorinated analogue 24,24-difluoro-1,25-(OH)2D3[24,24-F2-1,25-(OH)2D3] is an approximately fivefold more potent inhibitor of cellular replication than the native hormone, while 1,24R,25-(OH)3D3 is about fivefold less potent. This enhanced potency of the fluorinated analogue parallels its enhanced potency in in vivo studies of its effects on calcium and mineral metabolism. However, although the analogue retains replication stimulatory activity, it is clearly no more potent than the native hormone in this activity: 1,24R,25-(OH)3D3 has no significant stimulatory activity. Exposure of the cells to 1,25-(OH)2D3 at 0.05 nM for 6 h increases the subsequent conversion of labelled hormone to aqueous phase soluble compounds by 6.7-fold. None of the other compounds had a similar effect at this concentration. At 10 nM all 1-hydroxylated compounds increased aqueous phase radioactivity about equally (13 to 17-fold); this effect is still specific since 25-OH D3 had no such effect even at 10 nM. Studies on the effects of the fluorinated analogues upon receptor binding of hormone in cell cytosols and uptake of hormone by intact cells clearly demonstrate that the enhanced activity of these analogues is not due to higher receptor affinity or more rapid access to intracellular receptor.(ABSTRACT TRUNCATED AT 250 WORDS)     

Concentration of phosphoribosyl pyrophosphate in renal hypertrophy. Contrasting effects of early diabetes and unilateral nephrectomy.

Studies were made of the renal phosphoribosyl pyrophosphate (PPRibP) content and PPRibP synthetase (EC 2.7.6.1) activity in rats diabetic for 5, 14 or 20 days, or unilaterally nephrectomized (UN) for 5 days, and in doubly lesioned animals. Approximately equal degrees of renal enlargement were found after 5 days diabetes or 5 days UN. In the doubly lesioned animals the increment of growth was additive. Unilateral nephrectomy of 5 days duration, in contrast with diabetes, had no effect on the PPRibP content of the contralateral kidney, nor did it modify the renal PPRibP content when performed on animals diabetic for 5, 14 or 20 days. The activity of PPRibP synthetase was unaffected by diabetes, UN or diabetes +UN. The results pinpoint a stage of nucleotide synthesis which is differentially affected by the two stimuli, in line with evidence for differences in regulation of nucleic acid turnover in the two conditions.     

Human lecithin-cholesterol acyltransferase gene: complete gene sequence and sites of expression.

The human lecithin-cholesterol acyltransferase (LCAT) gene has been sequenced to completion. The gene is divided into six exons spanning approximately 4,200 bp. Exon five codes for amino acids homologous to the interfacial active site of several lipases, and also codes for an amphipathic alpha-helix resembling the carboxy terminus of apolipoprotein E. Blot hybridization data suggest that there is only one LCAT gene in humans. The 1550 base LCAT mRNA can be detected in liver and HepG2 (hepatocyte) cells, but not in small intestine, spleen, pancreas, placenta or adrenal tissue.     

Porphyran primary structure. An investigation using beta-agarase I from Pseudomonas atlantica and 13C-NMR spectroscopy

Porphyran, a highly substituted agarose from Porphyra umbilicalis was degraded by highly purified beta-agarase I from Pseudomonas atlantica. This enzyme cleaved at the reducing side of units of beta-neoagarobiose (3,6-anhydro-alpha-L-galactopyranosyl-(1 leads to 3)-beta-D-galactopyranose). The oligosaccharides were divided into fractions of low and high molecular weight by dialysis. The permeate (23% of total starting carbohydrate) was separated by ion-exchange into neutral and anionic fractions. Gel filtration of the neutral fraction (19%) resolved two major oligosaccharides. These were shown by 13C-NMR spectroscopy to be 6(3)-O-methyl-neoagarotetraose and 6(3),6(5)-di-O-methyl-neoagarohexaose. Gel filtration of the anionic oligosaccharides (3.3%) revealed two novel monosulphated tetrasaccharides, 6-O-sulphato-alpha-L-galacto-pyranosyl-(1 leads to 3)-beta-D-galactopyranosyl-(1 leads to 4)-3,6-anhydro-alpha-L-galactopyranosyl-(1 leads to 3)-D-galactopyranose and its 6(3)-O-methylated derivative. The 13C-NMR data from the sulphated tetrasaccharides provided a novel reference which was used to characterise higher, partially sulphated fragments in the dialysis permeate. The fraction retained on dialysis (77%) had an average degree of polymerisation of 40 and was homologous with the high-molecular-weight anionic permeate. From 13C-NMR spectroscopy porphyran was found to comprise 49% sulphated disaccharide units and these were calculated to occur in stretches averaging 2.0-2.5 contiguous units.