THE FROND OF HETERANGIUM

Frond members belonging to the monostelic seed fern genus Heterangium have been found in Pennsylvanian age coal balls collected in the Illinois Basin. Petioles bear small pinnae below a dichotomy which produced a bipartite frond. Pinnules of the Sphenopteris obtusiloba type are borne on secondary pinnae. The anatomy of each pinna order and the pinnules is described.     

Ultraviolet Devitalization of Eight Selected Enteric Viruses in Estuarine Water

The effect of ultraviolet (UV) radiation on the devitalization of eight selected enteric viruses suspended in estuarine water was determined. The surviving fractions of each virus were calculated and then plotted against the UV exposure time for purposes of comparison. Analytical assessment of the survival data for each virus consisted of least squares regression analysis for determination of intercepts and slope functions. All data were examined for statistical significance. When the slope function of each virus was compared against the slope function of poliovirus type 1, the analytical findings indicated that poliovirus types 2 and 3, echovirus types 1 and 11, and coxsackievirus A-9 exhibited similar devitalization characteristics in that no statistically significant difference was found (P > 0.05). Conversely, the devitalization characteristics of coxsackievirus B-1 and reovirus type 1 were dissimilar from those of poliovirus type 1 in that a statistically significant difference was found between the slope functions (P < 0.05). This observed difference in devitalization of coxsackievirus B-1 and reovirus type 1 was attributed primarily to the frequency distribution of single and aggregate virions, the geometric configuration, the size of the aggregates, and the severity of aggregation. The devitalization curve of coxsackievirus B-1 was characteristic of a retardant die-away curve. The devitalization curve of reovirus type 1 was characteristic of a multihittype curve. The calculated devitalization half-life values for poliovirus types 1, 2, and 3; echovirus types 1 and 11; coxsackievirus types A-9 and B-1; and reovirus type 1 were 2.8, 3.1, 2.7, 2.8, 3.2, 3.1, 4.0, 4.0 sec, respectively. These basic data should facilitate an operative extrapolation of the findings to the applied situation. It was concluded that UV can be highly effective and provide a reliable safety factor in treating estuarine water.     

Selective destruction of leucocytes by freezing as a potential means of modulating tissue immunogenicity: membrane integrity of lymphocytes and macrophages

It is now known, when a tissue allograft is transplanted, that antigen recognition alone is not sufficient for lymphocyte activation in the host. "Passenger" leucocytes (antigen-presenting cells) present in the donor tissue are now recognized as a major immunogenic stimulus. Removal of these contaminating leucocytes, using a variety of procedures, has enabled the immunogenicity of allografts to be reduced, thus enhancing the survival of tissue allografts. This initial study explores the possibility of using a cryobiological approach to modulating the immunogenicity of tissues by virtue of the well-recognized differential susceptibility of different cell types to freezing injury. The investigation was prompted by demonstrations that pancreatic islets can secrete insulin in response to a graded glucose challenge after cryopreservation using relatively fast cooling rates which would be expected to be suboptimal for leucocyte survival. Batches of rat peripheral blood lymphocytes, or peritoneal exudate cells (macrophages) were cooled at 0.3, 1, 5, 20, 75, or 200 degrees C/min using three different cryopreservation protocols reported to yield viable pancreatic islets. Cell survival was evaluated in terms of the numbers of cells recovered after freezing as well as a fluorometric viability assay which assessed the membrane integrity of cells. Optimum survival of both lymphocytes and macrophages after freezing and thawing was found at cooling rates in the range of 0.3 to 5 degrees C/min. A significant number (10-40%) of these lymphoid cells survived freezing at 20 degrees C/min and only after cooling at rates greater than 75 degrees C/min was survival reduced to a negligible level.     

SULLITHECA DACTYLIFERA GEN. ET SP. N.: A NEW MEDULLOSAN POLLEN ORGAN AND ITS EVOLUTIONARY SIGNIFICANCE

The pteridosperm (Medullosaceae) pollen organ Sullitheca dactylifera gen. et sp. n. is described from middle Pennsylvanian coal balls. The proximally fused units of the obpyriform compound synangium separate and extend distally as finger-like projections. Each projection contains 4–6 vertically oriented cylindrical sporangia arranged in pairs along the radius of the unit; each unit extends from the outer cover wall toward the center. The distal portion of the compound synangium is hollow as a result of the lateral separation of the centripetally and distally directed synangial units. About 40 tubular sporangia are present in all and dehiscence occurs along a lateral slit in each sporangium. Vascular strands are disposed around the periphery of the organ in addition to a single strand paralleling each sporangium. Two- or three-cell trichomes and stomata are present on the organ surface. Pollen of the Monoletes type is present. A paired row of sporangia in Sullitheca composing a synangial unit is considered the homologue of a paired row of sporangia in the more compact and highly evolved genus, Dolerotheca.     

Correction to: Reef-associated fishes have more maneuverable body shapes at a macroevolutionary scale

Coral Reefs - This erratum has been initiated as several formatting errors were overlooked during proofing stage by vendor.     

Morphological disparity in theropod jaws: comparing discrete characters and geometric morphometrics

Disparity, the diversity of form and function of organisms, can be assessed from cladistic or phenetic characters, and from discrete characters or continuous characters such as landmarks, outlines, or ratios. But do these different methods of assessing disparity provide comparable results? Here we provide evidence that all metrics correlate significantly with each other and capture similar patterns of morphological variation. We compare three methods of capturing morphological disparity (discrete characters, geometric morphometric outlines and geometric morphometric landmarks) in coelurosaurian dinosaurs. We standardize our study by focusing all our metrics on the mandible, so avoiding the risk of confounding disparity methods with anatomical coverage of the taxa. The correlation is strongest between the two geometric morphometric methods, and weaker between the morphometric methods and the discrete characters. By using phylogenetic simulations of discrete character and geometric morphometric data sets, we show that the strength of these correlations is significantly greater than expected from the evolution of random data under Brownian motion. All disparity metrics confirm that Maniraptoriformes had the highest disparity of all coelurosaurians, and omnivores and herbivores had higher disparity than carnivores.     

Cloning and functional characterization of an NAD(+)-dependent DNA ligase from Staphylococcus aureus

A Staphylococcus aureus mutant conditionally defective in DNA ligase was identified by isolation of complementing plasmid clones that encode the S. aureus ligA gene. Orthologues of the putative S. aureus NAD(+)-dependent DNA ligase could be identified in the genomes of Bacillus stearothermophilus and other gram-positive bacteria and confirmed the presence of four conserved amino acid motifs, including motif I, KXDG with lysine 112, which is believed to be the proposed site of adenylation. DNA sequence comparison of the ligA genes from wild type and temperature-sensitive S. aureus strain NT64 identified a single base alteration that is predicted to result in the amino acid substitution E46G. The S. aureus ligA gene was cloned and overexpressed in Escherichia coli, and the enzyme was purified to near homogeneity. NAD(+)-dependent DNA ligase activity was demonstrated with the purified enzyme by measuring ligation of (32)P-labeled 30-mer and 29-mer oligonucleotides annealed to a complementary strand of DNA. Limited proteolysis of purified S. aureus DNA ligase by thermolysin produced products with apparent molecular masses of 40, 22, and 21 kDa. The fragments were purified and characterized by N-terminal sequencing and mass analysis. The N-terminal fragment (40 kDa) was found to be fully adenylated. A fragment from residues 1 to 315 was expressed as a His-tagged fusion in E. coli and purified for functional analysis. Following deadenylation with nicotinamide mononucleotide, the purified fragment could self-adenylate but lacked detectable DNA binding activity. The 21- and 22-kDa C-terminal fragments, which lacked the last 76 amino acids of the DNA ligase, had no adenylation activity or DNA binding activity. The intact 30-kDa C terminus of the S. aureus LigA protein expressed in E. coli did demonstrate DNA binding activity. These observations suggest that, as in the case with the NAD(+)-dependent DNA ligase from B. stearothermophilus, two independent functional domains exist in S. aureus DNA ligase, consisting of separate adenylation and DNA binding activities. They also demonstrate a role for the extreme C terminus of the ligase in DNA binding. As there is much evidence to suggest that DNA ligase is essential for bacterial survival, its discovery in the important human pathogen S. aureus indicates its potential as a broad-spectrum antibacterial target for the identification of novel antibiotics.     

Inverse relationship between PGC-1alpha protein expression and triacylglycerol accumulation in rodent skeletal muscle.

PGC-1alpha is a key regulator of tissue metabolism, including skeletal muscle. Because it has been shown that PGC-1alpha alters the capacity for lipid metabolism, it is possible that PGC-1alpha expression is regulated by the intramuscular lipid milieu. Therefore, we have examined the relationship between PGC-1alpha protein expression and the intramuscular fatty acid accumulation in hindlimb muscles of animals in which the capacity for fatty acid accumulation in muscle is increased (Zucker obese rat) or reduced [FAT/CD36 null (KO) mice]. Rates of palmitate incorporation into triacylglycerols were determined in perfused red (RG) and white gastrocnemius (WG) muscles of lean and obese Zucker rats and in perfused RG and WG muscles of FAT/CD36 KO and wild-type (WT) mice. In obese Zucker rats, the rate of palmitate incorporation into triacylglycerol depots in RG and WG muscles were 28 and 24% greater than in lean rats (P < 0.05). In FAT/CD36 KO mice, the rates of palmitate incorporation into triacylglycerol depots were lower in RG (-50%) and WG muscle (-24%) compared with the respective muscles in WT mice (P < 0.05). In the obese animals, PGC-1alpha protein content was reduced in both RG (-13%) and WG muscles (-15%) (P < 0.05). In FAT/CD36 KO mice, PGC-1alpha protein content was upregulated in both RG (+32%, P < 0.05) and WG muscles (+50%, P < 0.05). In conclusion, from studies in these two animal models, it appears that PGC-1alpha protein expression is inversely related to components of intramuscular lipid metabolism, because 1) PGC-1alpha protein expression is downregulated when triacylglycerol synthesis rates, an index of intramuscular lipid metabolism, are increased, and 2) PGC-1alpha protein expression is upregulated when triacylglycerol synthesis rates are reduced. Therefore, we speculate that the intramuscular lipid sensing may be involved in regulating the protein expression of PGC-1alpha in skeletal muscle.