Annual net production and life span of floating leaves in Nymphaea tetragona Georgi: a comparison with other floating-leaved macrophytes

Fredericella sultana (Blumenbach, 1779) has long been considered one of the few freshwater bryozoan species with a truly cosmopolitan distribution. However, chromosome spreads from European material show 2n = 16 compared to 2n = 14 in North American specimens. In laboratory rearing the two forms are morphologically indistinguishable except for the surface texture of their statoblasts. Smooth statoblasts of European colonies match early illustrations of the species, while the densely pitted statoblasts of the North American form resemble those of F. indica Annandale 1909. On the basis of these observations we tentatively designate the North American F. sultana as F. indica. The only known American species with smooth statoblasts is F. australiensis Goddard 1909, in which the 2n = 16 karyotype is similar or identical to European F. sultana; however, despite this karyotypic similarity the two species retain their distinguishing morphology when reared together in the laboratory. Two enzymes from a single specimen of European F. sultana were electrophoretically distinct from the corresponding enzymes present in samples of both F. australiensis and North American F. sultana. Four phosphoglucose isomerase alleles were present in North American F. aultana from four geographically separated collection sites, although only one genotype for this locus was observed in material from any one site. These genetic findings are consistent with a relatively short-range dispersal potential in this species as compared to Plumatella species.     

Structure of indole-3-acetic acid myoinositol esters and pentamethyl-myoinositols

GC-MS properties of three isomeric esters of indole-3-acetic acid and myoinositol, three esters of indole-3-acectic acid and myoinositol arabinoside and three esters of indole-3-acetic acid and myoinositol galactoside are presented. MS fragmentation patterns for the four possible pentamethyl myoinositols are also shown. These data indicated that the arabinose, and galactose of the glycosides were in the pyranose form and that C-1 of the sugar was linked to the 5 hydroxyl of myoinositol. Homologies in fragmentation patterns for the esters and the glycoside esters, together with knowledge of the properties of 2-O-indole-3-acetyl-myoinositol, permitted identification of one of the arabinosides as 5-O-l-arabinopyranosyl-2-O-indole-3-acetyl-myoinositol and one of the galactosides as 5-O-d- galactopyranosyl-2-O-indole-3-acetyl-myoinositol. The remaining two GLC peaks observed for the arabinoside were then, most likely, the two mixtures of diastereoisomers 1 d- and 1 l-5-O-l-arabinopryranosyl-1-O-indole-3-acetyl myoinositol and 1 d- and 1 l-5-O-l-arabinopyranosyl-4-O-indole-3-acetyl-myoinositol. The remaining two GLC peaks observed for the galactoside would then be the 1 d and 1 l-5-O-d-galactopyranosyl-1-O-indole-3-acetyl-myoinositol and 1 d- and 1 l-5-O-d- galactopyranosyl-4-O-indoleacetyl-myoinositol.     

Studies on the interference among larvae of the citrus leaf miner,Phyllocnistis citrella stainton (lepidoptera: Phyllocnistidae)

Observation of the citrus leaf miner, Phyllocnistis citrellaStainton suggested that contacts among larvae frequently occur and either of two larvae encountered is sometimes killed by the interference. A model to describe the competitive interactions in the process of interference was constracted with this species. The distribution of hatchling on an area was considered in the model. The model was based on that of encounters in randomly moving particles in two dimensions. First the time when first death occurs was calculated and n hatchlings were reduced to n−1. Further calculation was made to obtain the time that next death occurs. Such calculation was repeated until the number of larvae was reduced to 1 or the area of mine attained to the completed size. By the simulation based on the data observed on the citrus leaf miner, the numbers of survivors were calculated at different hatchling densities and on different leaves in size. Based on this simulation analysis it was suggested that the following characteristics observed in the present studies enable the maximul number of individuals to become adults.

1. When two hatchlings occur on a leaf, they tend to be separated by the midrib. This implies that female moths tend to reject to lay eggs on the area which has already contained the egg.
2. The larva sometimes avoids the contact immediately before it occurs.
3. The larval mortality caused by a contact is reduced with the larval growth. Since the frequency of contacts increases as the mine is enlarged, the change to high survival prevents the larva from high mortality caused by the increase of contacts.
4. The larval survival does not decrease in spite of the reduction of the area available for mining.

     

Degradation of thyroxine by the microsomal particles from rat liver: I. Correlation between thyroxine degradation and lipid peroxides

1.

1. Particles which catalyze the degradation of l-thyroxine labeled with ¹³¹I at the 3′ and 5′ positions in the β-ring have been isolated from rat liver microsomes and purified.     

Generation of prostacyclin-like substance and lipid peroxidation in vitamin E-deficient rats

Endogenous generation of prostacyclin (PGI₂)-like substance and lipid peroxidation were studied in the aorta of rats fed on vitamin E-deficient diet and/or vitamin E-supplemented one for 4 to 10 months after they were weaned at 4 weeks. PGI₂-like substance was produced by the incubation of the aortic ring in pH 9.0 borate-buffered saline and was estimated by comparison of its antiaggregatory activity with that produced by known amounts of synthetic PGI₂. Thiobarbituric acid-reacting substance (TBARS) was determined as an indicator of lipid peroxidation. The generation of PGI₂-like substance was significantly reduced in rats fed on vitamin E-deficient diet for 8 and 10 months as compared with that in the animals fed on vitamin E-supplemented one for the same period (p<0.001). Mean concentration of TBARS in the aortae of rats fed on vitamin E-deficient diet for 10 months was significantly higher than that of the animals fed on vitamin E-supplemented diet for the same feeding period (p<0.001). These alterations in the aortae of rats fed on vitamin E-deficient diet were corrected by feeding them on vitamin E-supplemented diet for subsequent 2 months.     

Effect of lysine succinylation on the regulation of 2-oxoglutarate dehydrogenase inhibitor,OdhI, involved in glutamate production in Corynebacterium glutamicum

In Corynebacterium glutamicum, the activity of the 2-oxoglutarate dehydrogenase (ODH) complex is negatively regulated by the unphosphorylated form of OdhI protein, which is critical for L-glutamate overproduction. We examined the potential impact of protein acylation at lysine (K)-132 of OdhI in C. glutamicum ATCC13032. The K132E succinylation-mimic mutation reduced the ability of OdhI to bind OdhA, the catalytic subunit of the ODH complex, which reduced the inhibition of ODH activity. In vitro succinylation of OdhI protein also reduced the ability to inhibit ODH, and the K132R mutation blocked the effect. These results suggest that succinylation at K132 may attenuate the OdhI function. Consistent with these results, the C. glutamicum mutant strain with OdhI-K132E showed decreased L-glutamate production. Our results indicated that not only phosphorylation but also succinylation of OdhI protein may regulate L-glutamate production in C. glutamicum.     

Effects of Preterm Birth on Intrinsic Fluctuations in Neonatal Cerebral Activity Examined Using Optical Imaging

Medical advancements in neonatology have significantly increased the number of high-risk preterm survivors. However, recent long-term follow-up studies have suggested that preterm infants are at risk for behavioral, educational, and emotional problems. Although clear relationships have been demonstrated between preterm infants and developmental problems during childhood and adolescence, less is known about the early indications of these problems. Recently, numerous studies on resting-state functional connectivity (RSFC) have demonstrated temporal correlations of activity between spatially remote cortical regions not only in healthy adults but also in neuropathological disorders and early childhood development. In order to compare RSFC of the cerebral cortex between preterm infants at term-equivalent ages and full-term neonates without any anatomical abnormality risk during natural sleep, we used an optical topography system, which is a recently developed extension of near-infrared spectroscopy. We clarified the presence of RSFC in both preterm infants and full-term neonates and showed differences between these groups. The principal differences were that on comparison of RSFC between the bilateral temporal regions, and bilateral parietal regions, RSFC was enhanced in preterm infants compared with full-term neonates; whereas on comparison of RSFC between the left temporal and left parietal regions, RSFC was enhanced in full-term neonates compared with preterm infants. We also demonstrated a difference between the groups in developmental changes of RSFC related to postmenstrual age. Most importantly, these findings suggested that preterm infants and full-term neonates follow different developmental trajectories during the perinatal period because of differences in perinatal experiences and physiological and structural development.     

Studies on Synthetic Pyrethroid

Methyl αδ-dimethylsorbate, when submitted to the selective oxidation sequence by the actions of perbenzoic acid, mineral acid, lead tetraacetate and peracetic acid in this order, finally gives β-monomethyl mesaconate, which is converted after hydrolysis to mesaconic acid of the well-defined trans-configuration. The reaction sequence involves no process likely to invert the configuration, and thus another cogent chemical evidence for the trans-configuration of αδ-dimethylsorbic acid is obtained in agreement with the physico-chemical conclusion, previously reported.     

PMR Study on the Absolute Structure of Kanamycins and Related Compounds

The antioxidant behaviors of vitamin E and its analogues, 2, 2, 5, 7, 8-pentamethyl-6-hydroxychroman and l, 2-diacyl-sn-glycero-3-phospho-2?-(hydroxyethyl)-2?, 5?, 7?, 8?-tetramethyl-6?-hydroxychro-man, were studied in unilamellar vesicles. The two analogues scavenged aqueous radicals generated from azo compounds more efficiently than vitamin E. On the other hand, vitamin E scavenged the lipid peroxyl radicals preferentially. It is concluded that the superior antioxidant activity of vitamin E is attributed to its location suitable for breaking the chain propagation reaction.