Behaviors of southern red oak hemicelluloses and lignin in a mild sulfuric acid hydrolysis

Removal and modification of southern red oak hemicelluloses and lignin in a 0.05%(w/v) sulfuric acid hydrolysis were investigated. The hydrolysis profile was to raise the reaction from room temperature to 150 degrees C for in 38 min and to extend the hydrolysis at 150 degrees C for 1 h. At the end of the hydrolysis, 25.5% of red oak components were dissolved, of which 58% was xylose and 17% lignin. As the hydrolysis proceeded from room temperature to 150 degrees C, a part of red oak xylan was removed to yield an oligomer fraction having maximal yield and average molecular weight of 3460 at 150 degrees C. This fraction and the bulk xylan extracted during the first 30 min at 150 degrees C were further degraded to give a lower molecular weight oligomer fraction, of which the yield and average molecular weight (2610) were highest at the end of the bulk removal of xylan. Red oak lignin, syringyl and guaiacyl units in particular, was increasingly removed with the progress of the hydrolysis. Lignin derivatives and a part of red oak extractives soluble in the hydrolysate were identified.     

Correlative ultrastructural and electrophysiological studies of sperm-egg interactions of the sea urchin, Lytechinus variegatus

The sequence of ultrastructural events following the onset of the sperm-induced conductance increase in eggs of the sea urchin, Lytechinus variegatus, was investigated. Eggs voltage clamped at -20 mV were fixed 1 to 20 sec after onset of the conductance increase caused by single sperm. Continuity between the plasma membranes of the sperm and egg was first detected 5 sec after onset of the conductance increase. The earliest stages of formation of the fertilization cone coincided with the establishment of continuity of the gamete plasma membranes. At 6 to 8 sec after the initial conductance increase cortical granule dehiscence was first observed in the immediate vicinity where continuity of the gamete plasma membranes had occurred. These observations are consistent with the conclusion that opening of ion channels at fertilization precedes fusion of the sperm and egg plasma membranes, while exocytosis of cortical granules is initiated following fusion of the sperm and egg plasma membranes.     

The endoscopic diagnosis of gastroesophageal malignancy. A cytologic review

Cytologic reports were compared to final diagnoses for 1,157 gastroesophageal samples from an eight-year period in order to evaluate the diagnostic accuracy of endoscopic cytology and to determine the significance of a "suspicious" cytologic report. In the subgroup of patients with adenocarcinoma evaluated by paired endoscopic biopsy and cytology, the relative and combined sensitivities of the sampling methods were studied. Cytologic examination was reported as positive or suspicious in 85% of 229 cases of malignancy. There were three false-positive diagnoses of squamous-cell carcinoma of the esophagus, representing 0.3% of all submitted samples. Suspicious cytologic reports were issued in 5% of all cases. The majority (63%) of patients with a suspicious cytologic report had a final diagnosis of malignancy, with gastric adenocarcinoma present in almost half of the cases. Adenocarcinoma was diagnosed in 168 of the patients. Combined endoscopic biopsy and cytology was more sensitive (96%) than biopsy alone (90%) in making the initial diagnosis. Cytology may be of particular value in the diagnosis of gastroesophageal malignancy when the lesions are small and superficial or where stricture precludes adequate biopsy. Regardless of the biopsy findings, patients with "suspicious" cytologic reports require careful reevaluation since a high percentage of those cases in our series were subsequently verified as having malignancy.     

Flow cytometric fluorescence emission spectrum analysis of Hoechst-33342-stained DNA in chicken thymocytes

Hoechst-33342-stained chicken thymocytes were analysed simultaneously on two fluorescence wavelength bands (green and violet) in our custom-built flow cytometer, and two major subsets were identified. In one subset (33% of the total) the emission spectrum remained constant with time, with little change in the respective green and violet fluorescence intensities. In the other subset (42% of the total) the green fluorescence increased during staining, resulting in a considerable change in the green-to-violet ratio, due to a change in the "shape" of the fluorescence emission with time. The data indicate that two binding sites, or two types of binding at the same site, exist in DNA for this dye and that these have different binding energies and, consequently, different fluorescence emission properties.     

Cells transformed with a ts viral src mutant are temperature sensitive for in vivo growth.

Studies on ts mutants of avian sarcoma viruses have previously implicated the src gene product (pp60src) kinase function in in vitro transformation. The role of src in vivo, however, has not been clearly defined. Using a sensitive and quantitative assay that was developed in chicken embryos (Chambers et al., Cancer Res. 42:4018-4025, 1982), we tested the in vivo tumorigenic properties of cells transformed with LA23, an avian sarcoma virus that is temperature sensitive for in vitro transformation. We found that the in vivo growth ability of these cells was temperature sensitive and that this in vivo behavior correlated with the in vitro transformation behavior (growth in soft agar and saturation density).     

A note on the use of metal species in microbiological tests involving growth media

The feasibility of using traditional growth media for biological testing of metal species, for example as potential microbiocides, was investigated. Significant interactions between both of the representative metal species studied, Cu²⁺ and FeEDTA, and the test media were found. It is recommended that the use of growth media for tests on metal species should be avoided.     

Conidia induce the formation of protoperithecia in Neurospora crassa: further characterization of white collar mutants

The treatment of undifferentiated mycelia with heavy suspensions of their own conidia triggers protoperithecial development. This effect was also observed with white collar (wc) mutants and suggests that the wc genes are not structural genes necessary for morphogenesis of protoperithecia but that they are probably involved in regulation.     

Population genetics of the metabolically related Adh,Gpdh and Tpi polymorphisms in Drosophila melanogaster I. Geographic variation in Gpdh and Tpi allele frequencies in different continents

Among Australasian populations from above 32.5° latitude there is a significant negative relationship between Gpdh ^F frequency and distance from the equator which is not explained by gametic disequilibrium with the linked inversion In(2L)t. This is consistent with the associations reported earlier for Gpdh ^F among populations covering comparable latitudes in North America and Europe/Asia. By contrast, Tpi allele frequencies are found to be significantly associated with distance from the equator in Australasia but not North America or Europe/Asia. The Tpi pattern in the different zones is essentially the same as that reported earlier for the Acph polymorphism, which maps only 0.2 cM away from the Tpi locus.There are now ten enzyme polymorphisms in D. melanogaster which have been screened for latitudinal associations in Australasia, North America and Europe/Asia. Allele frequencies at six of these loci show significant relationships with distance from the equator which are consistent across all three zones. These latitudinal associations are more prevalent for Group II than Group I enzymes. Values of genic heterozygosity averaged over the ten polymorphic loci and eleven other monomorphic systems do not vary with latitude but differ substantially between zones. Values of Nei's genetic distance between North American and European/Asian populations calculated from all 21 systems are equivalent to subspecific differences elsewhere in the genus.