Identification of challenged subarachnoid free cells.

Three distinct types of free cell contours are recognizable in scanning electron microscopy (SEM) on the leptomeningeal sheaths of dogs twelve days after an intrathecal injection of bacillus of dogs twelve days after an intrathecal injection of bacillus Calmette-Guerin (BCG). Macrophages posses abundant plasmalemnal blebs which are shown in transmission electron microscopy (TEM) to be composed of large membrane-bound vacuoles. Smooth surfaced lymphoblasts exhibit many basal microvilli that rest upon and often indent the plasmalemma of an underlying pial cell. Neutrophils display many microvilli over their rounded, chrysanthemum-like surfaces. The consistency with which these external features are expressed suggests that each cell type possesses characteristic surface topography, at least under these conditions of challenge.     

A laboratory study of the behavior of two species of grass shrimp (Palaemonetes pugio Holthuis and Palaemonetes vulgaris Holthuis) and the killifish (Fundulus heteroclitus Linneaus)

In this laboratory study, the frequency of locomotor behaviors for two grass shrimp species, Palaemonetes pugio and Palaemonetes vulgaris, and the killifish Fundulus heteroclitus were determined. Additional behaviors, such as grouping of grass shrimp, and pursuit by killifish, the grass shrimp's common predator, were also analyzed. The results show that mean behavioral frequencies for the two shrimp species were rarely significantly different statistically. Each shrimp species altered its behavior differently in the presence of the other shrimp species, but responded similarly to the presence of the predator. The results indicate that the response of each shrimp species to the predator was dependent upon the predator's size and health. In situations involving the large health predator, both grass shrimp species significantly reduced swimming, but did not show a significant difference in walking. Behavioral frequencies of large and small healthy killifish were not significantly different from each other when alone, but were significantly different in the presence of prey, while the large unhealthy killifish's behavior was significantly decreased in all situations compared to both the large and small health killifish.     

Temperature comparisons for antibody production in vitro by plaque-forming cells from trout, Salmo gairdneri (Richardson), and mice

Anterior kidney and splenic cells were taken from rainbow trout and splenic cells from BALB/c mice immunized with a T-dependent (sheep red blood cells) or T-independent (DNP-Ficoll) antigen. The cells were incubated at different temperatures in Jerne plaque assays (direct or passive haemolytic plaque assays). The optimum numbers of in vitro plaque-forming cells (PFC) after incubation with homologous complement were directly correlated with normal body temperatures of the respective species. The optimum incubation temperature was 37°C for mouse cells and 10°C for fish cells. Incubation of mouse cells at lower temperatures of 30, 20, 10, 4 or 0°C appeared to yield a direct line reduction in numbers of PFC. Trout cells developed significantly fewer PFC at 4 and 20°C and none at 30°C or above; however, significant numbers still appeared at 0°C. More PFC per million white blood cells were obtained from the anterior kidney; however, related to temperatures, no differences in development of numbers of PFC could be seen between the spleen and anterior kidney cells of trout. When the incubation time was lengthened for both trout and mouse cells held at low temperatures, the numbers of PFC approached those of the cells incubated at the optimum temperatures for 10 h.     

Contribution of sucrose synthase, ADP-glucose pyrophosphorylase and starch synthase to starch synthesis in developing pea seeds

Using genetic variability existing amongst nine pea genotypes (Pisum sativum L.), the biochemical basis of sink strength in developing pea seeds was investigated. Sink strength was considered to be reflected by the rate of starch synthesis (RSS) in the embryo, and sink activity in the seed was reflected by the relative rate of starch synthesis (RRSS). These rates were compared to the activities of three enzymes of the starch biosynthetic pathway [sucrose synthase (Sus), ADP-glucose pyrophosphorylase and starch synthase] at three developmental stages during seed filling (25, 50 and 75% of the dry seed weight). Complete sets of data collected during seed filling for the nine genotypes showed that, for all enzyme activities (expressed on a protein basis), only Sus in the embryo and seed coat was linearly and significantly correlated to RRSS. The contribution of the three enzyme activities to the variability in RSS and RRSS was evaluated by multiple regression analysis for the first two developmental stages. Only Sus activity in the embryo could explain, at least in part, the significant variability observed for both the RSS and the RRSS at each developmental stage. We conclude that Sus activity is a reliable marker of sink activity in developing pea seeds.     

Sea urchin Hox genes: insights into the ancestral Hox cluster

We describe the Hox cluster in the radially symmetric sea urchin and compare our findings to what is known from clusters in bilaterally symmetric animals. Several Hox genes from the direct-developing sea urchin Heliocidaris erythrogramma are described. CHEF gel analysis shows that the Hox genes are clustered on a < or = 300 kilobase (kb) fragment of DNA, and only a single cluster is present, as in lower chordates and other nonvertebrate metazoans. Phylogenetic analyses of sea urchin, amphioxus, Drosophila, and selected vertebrate Hox genes confirm that the H. erythrogramma genes, and others previously cloned from other sea urchins, belong to anterior, central, and posterior groups. Despite their radial body plan and lack of cephalization, echinoderms retain at least one of the anterior group Hox genes, an orthologue of Hox3. The structure of the echinoderm Hox cluster suggests that the ancestral deuterostome had a Hox cluster more similar to the current chordate cluster than was expected Sea urchins have at least three Abd-B type genes, suggesting that Abd-B expansion began before the radiation of deuterostomes.      

Genome and methylome of the oleaginous diatom <Emphasis Type="Italic">Cyclotella cryptica</Emphasis> reveal genetic flexibility toward a high lipid phenotype

Background

Improvement in the performance of eukaryotic microalgae for biofuel and bioproduct production is largely dependent on characterization of metabolic mechanisms within the cell. The marine diatom Cyclotella cryptica, which was originally identified in the Aquatic Species Program, is a promising strain of microalgae for large-scale production of biofuel and bioproducts, such as omega-3 fatty acids.

Results

We sequenced the nuclear genome and methylome of this oleaginous diatom to identify the genetic traits that enable substantial accumulation of triacylglycerol. The genome is comprised of highly methylated repetitive sequence, which does not significantly change under silicon starved lipid induction, and data further suggests the primary role of DNA methylation is to suppress DNA transposition. Annotation of pivotal glycolytic, lipid metabolism, and carbohydrate degradation processes reveal an expanded enzyme repertoire in C. cryptica that would allow for an increased metabolic capacity toward triacylglycerol production. Identification of previously unidentified genes, including those involved in carbon transport and chitin metabolism, provide potential targets for genetic manipulation of carbon flux to further increase its lipid phenotype. New genetic tools were developed, bringing this organism on a par with other microalgae in terms of genetic manipulation and characterization approaches.

Conclusions

Functional annotation and detailed cross-species comparison of key carbon rich processes in C. cryptica highlights the importance of enzymatic subcellular compartmentation for regulation of carbon flux, which is often overlooked in photosynthetic microeukaryotes. The availability of the genome sequence, as well as advanced genetic manipulation tools enable further development of this organism for deployment in large-scale production systems.

     

Optimization of fermentation conditions for thermostable cellulase production byThielavia terrestris

Summary Of the eighteen different carbon sources, solka floc was optimal for the induction of cellulases by the thermophilic fungusThielavia terrestris. The temperature optimum for growth was between 44–52°C. The effect of initial and controlled pH on fungal growth and cellulase production was investigated and the results obtained showed that the maximum volumetric productivity (6.07 I.U./1 per h) of filter paper activity was achieved when the pH was controlled at 4.5–5.0.     

Amino acid utilization by L-M strain mouse cells in a chemically defined medium

Summary The amino acid requirements of strain L-M mouse cells grown in a chemically defined medium (2×Eagle) containing only the 13 essential amino acids (EAA) were investigated. Medium and acid hydrolysate samples were analyzed for amino acid content by the method of ion exchange chromatography. The extent of utilization of the EAA differed;e.g. after 120 hr of cell growth without medium change, glutamine was exhausted from the medium; methionine, leucine, isoleucine, cystine, arginine, and valine were depleted 60 to 80%; other EAA were used to lesser extents. Although the EAA were used in excess of their requirements for protein synthesis, a correlation could generally be made between utilization and protein amino acid composition. Glutamine appeared to be, a growth-limiting factor. Use of U-¹⁴C-labeled glutamine indicated that over one-half of the metabolized glutamine was converted to carbon dioxide, 17% to cell material, and 15% was extracted from the amino acid pools. Nonessential amino acids (NEAA), viz. alanine, aspartic acid, glutamic acid, glycine, proline, and serine, were released into the medium during growth, and some were reutilized. Exogenous provision of these did not improve cell growth. In contrast to the other NEAA, only serine showed net utilization when provided exogenously. When glutamic acid largely replaced the glutamine in the medium, it exerted a sparing effect on the glutamine requirement for protein synthesis. Suggestions are given for the improvement of Eagle medium for cell growth. Supported by Research Grants CA 03720 and CA 11802 from the National Institutes of Health. Predoctoral, fellow supported, by Grant F01-GM-42156-02 from the National Institutes of Health.