Preservation of sorghum plant portions harvested,processed and ensiled at ten stages of maturity

Two varieties of grain sorghum were harvested at 10 intervals from 35–189 days post planting. Leaf, stem and head portions were separated before being prepared for chemical analysis or ensiled for 30 days in 1-1 silos with or without preservatives. The taller variety (FS-1b) accumulated 60% more dry matter than ORO-T with advancing plant maturity, while whole plant crude protein content decreased from near 20 to less than 7% for both varieties. Dry matter ensiling loss (DMEL) was different (P < 0.05) for each plant portion, but was lower and less variable after the 77-day harvest. Immature leaves and heads resulted in the greatest average DMEL of 31 and 24%, respectively. Propionic acid decreased DMEL, while an ammonia solution was ineffective when compared to control leaf, stem and heads. The DMEL of leaves was influenced (P < 0.05) by a varietal × modulus of fineness interaction while the stem exhibited an interaction with plant maturity × modulus of fineness. Modulus of fineness was not associated with levels of organic acid production in silages, but plant maturity significantly influenced acetic, propionic and butyric acid production in heads. These data indicated that numerous combinations of silage preservation techniques affected DMEL of sorghum plant portions at different maturities.     

Nonhost Root Penetration by Soybean Cyst Nematode

A total of 66 plants in 50 species were inoculated with eggs and juveniles of soybean cyst nematode, Heterodera glycines. Roots were stained and observed for penetration and development of the nematode. Twenty-six plants were not penetrated; twenty-three were penetrated, but there was no development of the nematode; eight were penetrated with some nematode development; two were penetrated and had considerable nematode development, but few nematodes, if any, matured; and seven were penetrated with many nematodes maturing. The penetration of nonhosts may imply some susceptibility and that populations eventually would build up on the penetrated plants. Plants not penetrated may be useful as rotation plants because no reproduction would occur.     

The amino acid sequences of chains a, b, and c that form the trimer subunit of the extracellular hemoglobin from Lumbricus terrestris

The extracellular hemoglobin of Lumbricus terrestris comprises four major heme-containing chains, a, b, c, and d in equal proportions. We have determined the amino acid sequences of chains a, b, and c which form a disulfide-linked trimer. Chains a, b, and c have 151, 145, and 153 residues and calculated molecular weights of 17,525, 16,254, and 17,289, respectively. The sequence of chain b, reported previously (Garlick, R. L., and Riggs, A. F. (1982) J. Biol. Chem. 287, 9005-9015) has been completely redetermined and found to contain 12 fewer residues than originally reported. Chains a and c both contain unusual, highly polar NH2-terminal extensions of 7 residues before the A helix. These segments must be close together because they are joined by a disulfide bond. We suggest that this structure, with seven negatively charged groups, may be part of a functionally important Ca2+-binding site in the trimer. Comparison of the sequences of chains a, b, and c with those of chain d (Shishikura, F., Snow, J. W., Gotoh, T., Vinogradov, S. N., and Walz, D. A. (1987) J. Biol. Chem. 262, 3123-3131) and the four chains of the hemoglobin of Tylorrhynchus heterochaetus (Suzuki, T., and Gotoh, T. (1986) J. Biol. Chem. 261, 9257-9267) shows that the number and positions of the cysteinyl residues are all conserved. This suggests that the extracellular hemoglobins from both the Oligochaeta and Polychaeta have the same number and configuration of disulfide bonds within the molecule. Phylogenetic analysis suggests that gene duplication first generated an intracellular hemoglobin branch and an extracellular hemoglobin branch. DNA coding for a signal peptide would have been acquired by the extracellular globin gene after this event. At least two further gene duplications are required to account for the present four polypeptide chains.     

Pulmonary angiotensin-converting enzyme kinetics after acute lung injury in the rabbit

Depression of lung endothelial cell metabolic function may be an early and sensitive indicator of lung damage. When such functions are measured in vivo, substrates injected usually must be limited to "trace" doses due to the significant hemodynamic effects of high doses of substrate. Under first-order conditions (i.e., trace doses) the enzyme or transport system rate constant Vmax/Km may be calculated, but independent estimates of each variable (Vmax and Km) are not available. We therefore used multiple indicator-dilution methods and higher substrate concentrations to apply a mathematical model, based on saturable kinetics that yield independent estimates of the apparent kinetic parameters Vmax and Km for pulmonary angiotensin-converting enzyme (ACE). We used the ACE substrate, [3H]benzoyl-phenylalanyl-alanyl-proline ([3H]BPAP) and made these measurements and also estimates of serotonin [5-hydroxytryptamine (5-HT)] removal, before and after acute lung injury induced by intratracheal administration of phorbol myristate acetate (PMA). PMA significantly depressed the percent 5-HT removal (62 +/- 3 to 44 +/- 4%) and BPAP percent metabolism (74 +/- 2 to 66 +/- 2), when trace amounts of either compound were injected as a bolus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Expression of hepatitis B virus large envelope polypeptide inhibits hepatitis B surface antigen secretion in transgenic mice.

The outer membrane of the hepatitis B virus consists of host lipid and the hepatitis B virus major (p25, gp28), middle (gp33, gp36), and large (p39, gp42) envelope polypeptides. These polypeptides are encoded by a large open reading frame that contains three in-phase translation start codons and a shared termination signal. The influence of the large envelope polypeptide on the secretion of hepatitis B surface antigen (HBsAg) subviral particles in transgenic mice was examined. The major polypeptide is the dominant structural component of the HBsAg particles, which are readily secreted into the blood. A relative increase in production of the large envelope polypeptide compared with that of the major envelope polypeptide led to profound reduction of the HBsAg concentration in serum as a result of accumulation of both envelope polypeptides in a relatively insoluble compartment within the cell. We conclude that inhibition of HBsAg secretion is related to a hitherto unknown property of the pre-S-containing domain of the large envelope polypeptide.     

The structure of hemocyanin II from the horseshoe crab, Limulus polyphemus. The amino acid sequence of the second largest cyanogen bromide fragment

Fourteen fragments have been isolated from hemocyanin component II of Limulus polyphemus by cleavage with CNBr. The amino acid sequence of the largest fragment, CNBr Ia has been reported (Yokota, E., and Riggs, A. F. (1984) J. Biol. Chem. 259, 4739-4749). The amino acid sequence of the 12 smaller fragments is reported in an accompanying paper (Moore, M. D., Behrens, P. Q., and Riggs, A. F. (1985) J. Biol. Chem. 261, 10511-10519). We have determined the amino acid sequence of the second largest fragment, CNBr Ib. The fragment contains 142 residues and has a molecular weight of 16,095.     

Cotyledon nuclear proteins bind to DNA fragments harboring regulatory elements of phytohemagglutinin genes.

The effects of deleting DNA sequences upstream from the phytohemagglutinin-L gene of Phaseolus vulgaris have been examined with respect to the level of gene product produced in the seeds of transgenic tobacco. Our studies indicate that several upstream regions quantitatively modulate expression. Between -1000 and -675, a negative regulatory element reduces expression approximately threefold relative to shorter deletion mutants that do not contain this region. Positive regulatory elements lie between -550 and -125 and, compared with constructs containing only 125 base pairs of upstream sequences (-125), the presence of these two regions can be correlated with a 25-fold and a 200-fold enhancement of phytohemagglutinin-L levels. These experiments were complemented by gel retardation assays, which demonstrated that two of the three regions bind cotyledon nuclear proteins from mid-mature seeds. One of the binding sites maps near a DNA sequence that is highly homologous to protein binding domains located upstream from the soybean seed lectin and Kunitz trypsin inhibitor genes. Competition experiments demonstrated that the upstream regions of a bean beta-phaseolin gene, the soybean seed lectin gene, and an oligonucleotide from the upstream region of the trypsin inhibitor gene can compete differentially for factor binding. We suggest that these legume genes may be regulated in part by evolutionarily conserved protein/DNA interactions.     

Localization of sequences regulating ancestral and acquired sites of esterase6 activity in Drosophila melanogaster

We have broadly defined the DNA regions regulating esterase6 activity in several life stages and tissue types of D. melanogaster using P- element-mediated transformation of constructs that contain the esterase6 coding region and deletions or substitutions in 5' or 3' flanking DNA. Hemolymph is a conserved ancestral site of EST6 activity in Drosophila and the primary sequences regulating its activity lie between -171 and -25 bp relative to the translation initiation site: deletion of these sequences decrease activity approximately 20-fold. Hemolymph activity is also modulated by four other DNA regions, three of which lie 5' and one of which lies 3' of the coding region. Of these, two have positive and two have negative effects, each of approximately twofold. Esterase6 activity is present also in two male reproductive tract tissues; the ejaculatory bulb, which is another ancestral activity site, and the ejaculatory duct, which is a recently acquired site within the melanogaster species subgroup. Activities in these tissues are at least in part independently regulated: activity in the ejaculatory bulb is conferred by sequences between -273 and -172 bp (threefold decrease when deleted), while activity in the ejaculatory duct is conferred by more distal sequences between -844 and -614 bp (fourfold decrease when deleted). The reproductive tract activity is further modulated by two additional DNA regions, one in 5' DNA (-613 to -284 bp; threefold decrease when deleted) and the other in 3' DNA (+1860 to +2731 bp; threefold decrease when deleted) that probably overlaps the adjacent esteraseP gene. Collating these data with previous studies suggests that expression of EST6 in the ancestral sites is mainly regulated by conserved proximal sequences while more variable distal sequences regulate expression in the acquired ejaculatory duct site.