Yield Results and Stability Analysis from the Sorghum Regional Biomass Feedstock Trial

Sorghum [Sorghum bicolor (L.) Moench] is one of four herbaceous dedicated bioenergy crops the U.S. Department of Energy identified as critical to annually produce one billion tons of dry biomass. Of these four crops, sorghum is unique as it is a drought-tolerant, annual crop established from seed that is readily tractable to genetic improvement. The purpose of this study was to assess the yield potential and stability of sorghums grown across diverse production environments in the USA. For this study, six sorghum genotypes (one cultivar, five hybrids) were grown in yield trials in seven locations in six states for 5 years (2008–2012). Variation in dry and fresh yield was attributable to not only genotypes, but also to the effects of year, location, and year × location. Even with the highest yielding genotype, environmental conditions were a major factor in determining the yield in a given year. This variability affects the consistency of the biomass supply for ethanol production. In general, the southeastern USA had the highest mean yields for fresh weight and dry weight, indicating that this area may be the most reliable for biomass production. A significant variation was detected among genotypes for fresh weight, dry weight, moisture content, and brix, revealing that sufficient variation within sorghum exists for continued improvement and that certain hybrids are more tractable for biomass/bioenergy production. With dedicated bioenergy sorghum germplasm and proper production environments, sorghum will be a valuable tool in the goal of the sustainable production of one billion tons of dry biomass each year in the USA.     

Flow rate and vertical position influence ingestion rates of colonial zebra mussels (Dreissena polymorpha)

1. Zebra mussels aggregate to form dense colonies where, depending on the flow rate, individuals in different vertical locations within the colony may experience restricted food availability. 2. Using ³²P‐labelled Chlamydomonas angulosa, we found ingestion rates of individual mussels located at the surface to exceed those in the bottom of a 6 cm thick colony by up to 75%. 3. Higher velocities (10 and 20 cm s^?1) increased algal delivery to the colony's middle layer (2–4 cm depth), subsequently increasing ingestion rates to equal those in the surface layer, while increasing ingestion only for the smallest mussels in the bottom (4–6 cm). 4. At all vertical locations within the colonies, smaller mussels showed higher ingestion rates per unit mass than larger mussels, particularly at higher flow rates.     

Centrally-mediated bombesin effects on gastrointestinal motility

Administration of bombesin into the lateral cerebral ventricle (i.c.v.) of rats results in a dose-related delay in gastric emptying and small intestinal transit. Recordings of intestinal intraluminal pressure in this species show that the i.c.v. peptide produces a dose-related increase in the frequency of duodenal contractions, and a complex inhibitory/excitatory jejunal effect at low and high doses, respectively. Intrathecal (i.th.) or i.c., but not intraperitoneal (i.p.), bombesin produces a dose-related slowing of gastrointestinal and colonic transit in mice. I.c.v. bombesin is 13.5 and 3406 times more potent in inhibition of gastrointestinal transit than when given by the i.th. or i.p. routes, respectively. Similarly, the i.c.v. peptide is 1.54 and over 11000 times more potent in slowing mouse colonic transit than when given by the i.th. or i.p. routes, respectively. The substance P analogue, D-Arg1, D-Pro2, D-Trp7,9, Leu11-Substance P (DAPTL-SP)(a reported bombesin antagonist in vitro) was not effective in blocking the gastrointestinal transit effects of the peptide in vivo. Transection of the spinal cord at the level of the second thoracic vertebra (T2) eliminates the gastrointestinal and colonic effects of i.th., but not i.c.v. bombesin. Thus, bombesin can affect motor function of the gut via activity within the brain or spinal cord of rats and mice; the activity of the peptide when given at the supraspinal level depends on an intact vagus nerve and adrenal-pituitary axis, while the activity of the peptide given at the spinal level appears to depend on the integrity of ascending spinal-supraspinal pathways.     

CABIOS REVIEW: The GenBank nucleic acid sequence database

‘The GenBank’^* nucleic acid sequence database isa computer-based collection of all published DNA and RNA sequences;it contains over five million bases in close to six thousandsequence entries drawn from four thousand five hundred publishedarticles. Each sequence is accompanied by relevant biologicalannotation. The database is available either on magnetic tape,on floppy diskettes, on-line or in hardcopy form. We discussthe structure of the database, the extent of the data and theimplications of the database for research on nucleic acids.     

Highly potent side chain–main chain cyclized dermorphin–deltorphin analogues: An integrated approach including synthesis,bioassays, NMR spectroscopy and molecular modelling

Our continuing efforts to study structure–activity relationships of peptide opioids have resulted in the synthesis of a series of cyclic opioids related to dermorphins and deltorphins. The biological activities of the compounds have been determined and the conformational analyses carried out using ¹H-NMR spectroscopy and molecular modelling. The three compounds in the series Tyr-c[D -Orn-Phe-Ala], Tyr-c[D -Lys-Phe-Ala], and Tyr-c[A₂Bu-Phe-Ala-Leu] are cyclized via a lactam bridge from the side-chain of the residue at the second position with the carboxyl terminus of each compound. The molecules incorporate 12-, 13- and 14-membered rings, respectively. They include a phenylalanine at the third position which is a distinguishing characteristic of dermorphins and deltorphins. The guinea pig ileum and mouse vas deferens assays show that the compounds are highly active at both μ- and δ-opioid receptors. The compounds are all highly effective antinociceptive agents as measured by the intrathecal rat hot plate test. Conformational analyses of the molecules indicate that they can adopt topochemical arrays required for bioactivity at both μ- and δ-receptors which explains their high activity in both guinea pig ileum and mouse vas deferens in vitro assays. The results support our models for μ- and δ-receptor activity for constrained peptide opioids.     

Overview of the LiMB database.

The rapidly increasing number of databases relevant to molecular biology has given rise to a need for a coordinated effort to identify, characterize, and link them. The LiMB database, which contains information about molecular biology and related databases, is a step in that direction. It serves molecular biologists seeking data sets containing information relevant to their research, and is also intended to anticipate the needs of database designers and managers building software links for related data sets. We present an abbreviated version of the database here; the full database is available free of charge as described below.     

Recombinant mouse ZP3 inhibits sperm binding and induces the acrosome reaction.

Mammalian fertilization involves interactions of sperm surface receptors with ligands of the zona pellucida, an extracellular matrix surrounding the ovulated egg. In mouse, the zona is composed of three glycoproteins. One of them, ZP3, participates in primary sperm binding and in the subsequent triggering of the sperm's acrosome reaction. Considerable evidence suggests that carbohydrate determinants of ZP3 are responsible for binding to sperm and may be important for acrosomal exocytosis. A full-length cDNA encoding mouse ZP3 was assembled and cloned into expression vectors that contained either a cytomegalovirus (CMV) or a vaccinia (P11) promoter. Mouse L-929 cells were stably transformed with the pZP3-CMV constructs, and green monkey CV-1 cells were infected with a recombinant vaccinia virus containing ZP3. rZP3 was affinity purified from culture media and detected on Western blots as a single 60- to 70-kDa band, which differed in molecular weight from native ZP3 (mean, 83 kDa). Nevertheless, rZP3 is biologically active. rZP3 decreases sperm-zona binding with a potency equivalent to that of native zona pellucida and, like native ZP3, rZP3 triggers acrosomal exocytosis in capacitated mouse sperm. Thus, rZP3 isolated from both rodent and primate cells appears to contain those carbohydrate and protein structures necessary for ZP3's dual role in fertilization.     

Influence of peptidase inhibitors on the apparent agonist potency of delta selective opioid peptides in vitro.

Several peptides of diverse structure, reported to possess high affinity and selectivity for the delta opioid receptor, were studied using the mouse isolated vas deferens preparation to determine the effect of peptidase inhibition on their apparent potency. The peptides evaluated included [Leu5] enkephalin, the cyclic enkephalin analogs [D-Pen2,D-Pen5]enkephalin (DPDPE) and [D-Pen2,p-F-Phe4,D-Pen5]enkephalin (F-DPDPE), the linear enkephalin analogs [D-Ala2,D-Leu5]enkephalin (DADLE) and [D-Ser2(O-tBu), Leu5,Thr6]enkephalin (DSTBULET), and the naturally occurring amphibian peptides Tyr-D-Met-Phe-His-Leu-Met-Asp-NH2 (dermenkephalin), Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH2 (deltorphin I) and Tyr-D-Ala-Phe-Glu-Val-Val-Gly-NH2 (deltorphin II). Concentration-response curves were determined for each peptide in the absence and presence of a combination of the peptidase-inhibiting agents bacitracin, bestatin, and captopril. A wide range of potencies was observed, both in the control state and in the presence of peptidase inhibition. The synthetic enkephalin analogs demonstrated small increases in potency with peptidase inhibition (no increase in the case of DPDPE), whereas the naturally occurring peptides were markedly increased in potency, up to as much as 123-fold for dermenkephalin. In the presence of peptidase inhibition, deltorphin II was the most potent peptide tested (IC50 = 1.13 x 10(-10) molar), and as such is the most potent delta opioid agonist reported to date. Stability to metabolism must be considered in the design and evaluation of in vitro experiments using peptides of this type.     

Light microscopic autoradiographic localization of [3H] substance P binding sites in rat thoracic spinal cord

We have used light microscopic autoradiography to look for the distribution of [³H] substance P receptors in the thoracic spinal cord of the rat. High densities of autoradiographic grains were localized to the intermedialateral cell column, the central canal and the substantia gelatinosa of the dorsal horn.