Regulation of potato tuber protein accumulation by gibberellic Acid

Many studies have shown that gibberellic acid (GA₃) inhibits tuberization in potato (Solanum tuberosum L.). In this study, we have utilized the 40 kilodalton glycoprotein, patatin, as a marker for biochemical events associated with the process of tuberization. To determine the effects of exogenous applications of GA₃ on the induction of the accumulation of this major tuber protein, we measured patatin levels in tubers from treated whole plants, petioles from a single-node cutting system with GA₃ applied in a lanolin paste, and stolon tips cultured in vitro on an inductive medium supplemented with GA₃. In all three systems, GA₃ inhibited the accumulation of patatin and the major 15 and 22 kilodalton tuber proteins. This effect appeared to be selective since most of the other proteins were not affected and, in tubers, at least one protein was stimulated by GA₃. These results suggest that GA₃ can reverse biochemical events of tuberization in tubers as well as prevent the accumulation of the major tuber proteins in other inducible tissues.     

Autointoxication in residues ofAsparagus officinalis L.

Summary In a greenhouse experiment the growth of asparagus seedlings was retarded by the residue treatments in both vermiculite and sand cultures. In general, the retardation of asparagus root by residues was slightly greater than the retardation of shoot in both cultures. The retardation of the growth of asparagus seedlings by root and stem treatments was usually higher than that by old root litter. Root and stem extracts strongly inhibited the development of asparagus seedlings in the seed bioassay. The inhibition of extracts to the growth of shoot was greater than that to the growth of root. The quantities in the total phenolics and catachol type phenolics from root, stem and old root litter extracts corresponded to the autotoxicity in the seed bioassay. The soil extracts obtained from using acetone, methanol, and XAD-4 extractions strongly inhibited the shoot and root development of asparagus seedlings in the bioassay. The efficiency of phenolics extraction by the XAD-4 method was significantly higher than that by acetone and methanol extractions. The results obtained in the greenhouse experiment and bioassay revealed that phytotoxic substances present in the residues and the soil of asparagus and may be partially responsible for the asparagus replanting problems.     

Resistance of citrus fruit to mass transport of water vapor and other gases

The resistance of oranges (Citrus sinensis L. Osbeck) and grapefruit (Citrus paradisi Macf.) to ethylene, O₂, CO₂, and H₂O mass transport was investigated anatomically with scanning electron microscope and physiologically by gas exchange measurements at steady state. The resistance of untreated fruit to water vapor is far less than to ethylene, CO₂ and O₂. Waxing partially or completely plugs stomatal pores and forms an intermittent cracked layer over the surface of fruit, restricting transport of ethylene, O₂, and CO₂, but not of water; whereas individual sealing of fruit with high density polyethylene films reduces water transport by 90% without substantially inhibiting gas exchange.

Stomata of harvested citrus fruits are essentially closed. However, ethylene, O₂ and CO₂ still diffuse mainly through the residual stomatal opening where the relative transport resistance (approximately 6,000 seconds per centimeter) depends on the relative diffusivity of each gas in air. Water moves preferentially by a different pathway, probably through a liquid aqueous phase in the cuticle where water conductance is 60-fold greater. Other gases are constrained from using this pathway because their diffusivity in liquid water is 10⁴-fold less than in air.

     

Partial expression of catecholaminergic traits in cholinergic chick ciliary ganglia: Studies in vivo and in vitro

We have previously demonstrated that at embryonic Day (E) 8, some cells of the chick ciliary ganglion (CG) contain the catecholaminergic (CA) enzyme tyrosine hydroxylase (TH), but not phenylethanolamine-N-methyltransferase (PNMT); and that in culture essentially all cells express both enzymes. In the present study, we sought to determine, first, whether the expression of adrenergic traits in the CG in vivo is transient or permanent in the CG. To do so, CGs were removed from E5 to postnatal Day 5, fixed, and processed for the immunocytochemical localization of the CA enzymes: TH, L-amino acid decarboxylase (AADC), and PNMT. At all stages examined, some CG neurons expressed TH immunoreactivity (TH-IR) and all contained AADC-IR. However, none stained with PNMT antibodies, indicating that these cells stably express some, but not all, of the CA enzymes. Second, we examined whether CG neurons in culture expressed other CA markers. CG neurons did not contain detectable levels of TH enzyme activity nor did they transport and store exogenously supplied monoamines. These results indicate that some but not all traits necessary for adrenergic function are present in CG neurons in vitro. Third, we sought to establish whether CA expression in CG neurons is affected by modification in culture conditions. Cultures of CG neurons continued to express TH-IR even when grown in the presence of either 50% HCM or 20 mM KCl for 5 days. Finally, the expression of the cholinergic enzyme, choline acetyltransferase (CAT) was assessed in CG cultures by biochemical assay. CAT activity increased five-fold between 5 and 17 days in vitro, irrespective of the presence of TH-IR in 100% of the CG neurons of sister cultures. These data suggest that at least a subpopulation of CG neurons express both TH and CAT in culture. We conclude that the postmitotic neurons of the CG are able to express some but not all of the traits characteristic of a CA phenotype while maintaining cholinergic expression. These findings suggest that (1) the appearance of the full complement of adrenergic properties is not coordinated and may be regulated by different environmental cues and (2) parasympathetic neurons can express both adrenergic and cholinergic traits simultaneously.     

Identification in several human myeloid leukemias or cell lines of a DNA rearrangement next to the c-mos 3'-end

A characteristic DNA rearrangement, the loss of an EcoRI cleavage site next to the 3'-end of the human c-mos gene, has been found to be frequently present in DNA from transformed hematopoietic cells of the myeloid lineage but not in DNA from either normal or transformed cells of different tissue types. Three established cell lines, respectively a pro-monocytic line (CM-S) and two precursor granulocytic lines (My/K1 and My/K5), carry the same genome rearrangement, but not fibroblasts obtained from the marrow of the same patients. This DNA rearrangement is maintained in three different hybridomas derived by fusion of CM-S cells with normal human embryo hepatocytes.     

Three types of transmitter release from embryonic neurons

Prior to the contact with their target muscle cells in culture, growth cones of many isolated Xenopus embryonic neurons release acetylcholine (ACh) spontaneously. Using patch clamp techniques, this release can be detected by an outside-out patch of muscle membrane placed near the growth cone. Intracellular recording from innervated muscle cells showed spontaneous miniature endplate potentials (MEPPs) of varying amplitudes. Amplitude histograms showed a skewed distribution with multiple peaks, suggesting the existence of subunits in either the quantal packages of ACh released by the nerve terminal or in the postsynaptic muscle response. In addition to the quantal ACh release reflected by MEPPs, nerve terminal also release a large amount of ACh in a non-quantal fashion. This non-quantal ACh release is revealed by the hyperpolarization of the muscle membrane following extracellular application of curare or alpha-bungarotoxin, as well as by denervation of the muscle cell.     

Methylation of type II and type I collagen genes in differentiated and dedifferentiated chondrocytes

The methyl-sensitive restriction endonucleases HpaII and HhaI as well as the methyl-insensitive enzyme MspI were used to examine the methylation status of the pro-alpha 1(II) collagen gene of cartilage. Five different cell types with varying abilities to express type II collagen were studied. Chick embryo chondrocytes express type II collagen, while 5-bromodeoxyuridine-treated chondrocytes, retinoic acid-treated chondrocytes, chick embryo fibroblasts, and erythrocytes do not synthesize type II collagen. Both cDNA and genomic probes for the pro-alpha 1(II) collagen gene were used, covering the complete 3' end of the gene and its flanking sequences. The pro-alpha 1(II) collagen DNA was undermethylated in chondrocytes, compared to either fibroblasts or erythrocytes. However, the methylation of the 5-bromodeoxyuridine-treated and retinoic acid-treated chondrocytes was identical to that of control chondrocytes. The methylation pattern of two regions of the gene of the pro-alpha 2(I) collagen chain was identical in all cell types tested, whether or not the gene was expressed. Our results indicate that genes for these collagen chains differ in their methylation pattern. The type II collagen gene shows reduced methylation in expressing cartilage, but does not acquire an increase in methylation in "dedifferentiated" chondrocytes. The changes in DNA methylation that occur during cell differentiation do not appear to be sufficient to explain gene activation and deactivation.     

Purification and sequencing of the active site tryptic peptide from penicillin-binding protein 5 from the dacA mutant strain of Escherichia coli (TMRL 1222)

The localization of the active site of penicillin-binding protein 5 from the dacA mutant of Escherichia coli strain TMRL 1222 has been determined. The protein was purified to homogeneity and labeled with [14C] penicillin G. The labeled protein was digested with trypsin, and the active site tryptic peptide was purified by a combination of gel filtration and high-pressure liquid chromatography. Sequencing of the purified [14C]penicilloyl peptide yielded the sequence Arg-Asp-Pro-Ala-Ser-Leu-Thr-Lys, which corresponds to residues 40-47 of the gene sequence (Broome-Smith, J., Edelman, A., and Spratt, B. G. (1983) in The Target of Penicillin (Hakenbeck, R., Holtje, J.-V., and Labischinski, H., eds) pp. 403-408, Walter de Gruyter, Berlin). The catalytic amino acid residue that forms a covalent bond with penicillin was identified by treating the purified [14C]penicilloyl peptide with a mixture of proteases and then separating the radioactive products using high-pressure liquid chromatography. Analysis of the radioactive peaks by amino acid analysis confirmed that it is the serine residue that reacts with the beta-lactam ring of penicillin.     

Immunochemical Characterization of Pyruvate Dehydrogenase Complex in Rat Brain

Pyruvate dehydrogenase complex (PDHC) in rat brain was studied immunochemically, using antibodies against the bovine kidney PDHC, by immunoblotting, immunoprecipitation, inhibition of enzyme activity, and enzyme-linked immunoabsorbent assay (ELISA). The immunoblots showed that the antibodies bound strongly to the alpha peptide of the pyruvate dehydrogenase (E1) component, and to the dihydrolipoyl transacetylase (E2) and the dihydrolipoyl dehydrogenase (E3) components of PDHC. A similar immunoblotting pattern was observed in all eight brain regions examined. On immunoblotting of the subcellular fractions, these PDHC peptides were observed in mitochondria and synaptosomes but not in the postmitochondrial supernatants. This agrees with other evidence that brain PDHC is localized in the mitochondria. These results, together with those from sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the immunoprecipitin, also showed that the alpha E1, beta E1, and E3 peptides of rat brain PDHC are very similar in sizes to those of the bovine kidney PDHC, being 42, 36, and 58 kD, respectively. The size of the E2 peptide, 66 kD, is different from that of bovine kidney E2, 73 kD. The relative abundance of PDHC protein in nonsynaptic mitochondria was compared by enzyme activity titration and ELISA. Both methods demonstrated that the amount of PDHC antigen in the mitochondria from cerebral cortex is greater than that in the olfactory bulb mitochondria. This is consistent with the results of the activity measurement. The ELISA also showed that the PDHCs in both mitochondrial populations are antigenically similar.(ABSTRACT TRUNCATED AT 250 WORDS)     

Massive scrotal edema as a complication of abdominoplasty

Massive scrotal edema is an unreported complication of abdominoplasty. This patient's postoperative decompensation of medial thigh and scrotal lymphatic return may well have been due to an occult lymphedema tarda or previously compromised lymphatics from the fibrosis of venous stasis disease and obesity.