Productivity and mineral cycling in an oak coppice forest 2. Annual net production of the forest

Annual net production was estimated in the secondary coppice forest near Tokyo, which was dominated by a deciduous oak,Quercus serrata Thunb. Lateral growth of stems and old branches was directly estimated by examining the annual rings for 35 shoots in a clear-cut quadrat of 10m×10m. Phytomasses of current organs were also weighed in the quadrat. Preharvest losses of current organs were determined by twelve 0.5 m² litter traps for fine litter and twelve 6 m² quadrats for woody litter. Branch production was also assessed indirectly by use of the stem-branch allometry and death of branches. The results of the indirect method were in sufficient agreement with the result of the direct one. Grazing loss of leaves from the canopy was estimated directly from the loss in leaf area and indirectly from the animal faeces caught by the litter traps. Net production of the canopy trees was 149 kg a⁻¹ year⁻¹, in which leaf production was 36.9 kg. Animals grazed about 14% of the leaf area by the end of the growing season. True consumption of leaves by animals was 7.6% of leaf production or 10% of leaf mass. Production of undergrowth, mainly a dwarf bamboo,Pleioblastus chino Makino, was 28 kg a⁻¹ year⁻¹, being 15% of the total stand production. Productivity of this forest was significantly higher than that of cool-temperate deciduous broadleaf forests.     

The changes of nuclear position and distribution of circumferentially aligned cortical microtubules during the progression of cell cycle inAdiantum protonemata

The intracellular positions of the nucleus and of cortical, circumferentially aligned microtubules (CCAM) in filamentous, single-celled protonemata ofAdiantum capillus-veneris were determined throughout the cell cycle in the dark. When apical growth continued at G₁ phase, the nucleus migrated keeping a constant distance from the tip. When the apical growth stopped at late S or G₂ phase, the nucleus stopped moving forward and then slightly moved backward to the site of cytokinesis. The CCAM were found only in the dome of protonemal tip when growing under continuous red light; they increased in number after dark incubation for 12 hr and then decreased after 20th hr in the dark. The CCAM were usually observed in the region between the nucleus and the tip at 28 hr in the dark. They were located around the nuclear region at pre-prophase and prophase, but then totally disappeared at metaphase and thereafter.     

Sexual differentiation in population of prothallia inLygodium japonicum

InLygodium japonicum, the archegonium was formed when the prothallium grew to approximately 1.5 mm in width irrespective of age, photoperiod, temperature or concentration of sucrose in the medium. Surgically cut prothallia produced archegonia only when the fragments regenerated to ca. 1 mm in width. Prothallia of smaller dimensions formed antheridia rather than archegonium, but only if archegoniated prothallia of the larger size coexisted in the population. Antheridiogens and inhibitors of archegonial differentiation became detectable by bioassay in conditioned media of 14-and 16-day-old prothallia, respectively, and continued to accumulate in the medium during culture in the light at 25 C. Twelve-day-old or younger prothallia are very sensitive to exogenously applied hormonal substances, whereas by day 14 the response had diminished.     

Stimulating factor for calf thymus DNA polymerase β

A factor that stimulates purified DNA polymerase β about 2-fold was separated from DNA polymerase β activity on a DNA-cellulose column. During the early stage of purification, the factor may be associated with DNA polymerase β to form a complex that sediments at 3.9 S in sucrose gradients and behaved as a 52,000 dalton protein on a Sephadex G-100 column. The complex, which contains 40,000 and 12,500 dalton polypeptides, was insensible to the stimulator, and did not show any exonuclease activity.     

Eu-actinin, a new structural protein of the Z-line of striated muscles

A new protein component of the Z-line of striated muscles was isolated from chicken breast muscle. This protein has been designated as eu-actinin because of its close similarity in polypeptide molecular weight to actin. Eu-actinin was extracted from myosin-removed myofibrils at low ionic strength at pH 6.5 and purified by column chromatography on Sepharose 4B and DEAE-cellulose. Although the polypeptide molecular weight of eu-actinin measured by SDS-polyacrylamide gel electrophoresis is similar to that of actin, other physico-chemical properties of eu-actinin definitely differ from those of actin. The isoelectric point of eu-actinin was more acidic than that of actin. The amino acid composition of eu-actinin was found to be different from that of actin or those of other muscle structural proteins. The results of analytical gel filtration on Sepharose 4B indicated that eu-actinin forms dimers through non-covalent bonding under aqueous conditions. Eu-actinin has a low axial asymmetry under low-salt conditions, as judged from its intrinsic viscosity ([eta] = 6.4 ml/g for the dimer state) and exhibits a tendency to undergo self-association with increasing ionic strength. Interactions of eu-actinin with other muscle proteins were examined by the affinity column technique. It was shown that eu-actinin binds to actin and alpha-actinin. Eu-actinin exhibited strong seeding ability for the polymerization of actin. Antibody to eu-actinin was raised in a goat and purified by affinity chromatography. The specific antibody against eu-actinin did not form precipitine lines with actin or alpha-actinin. Immunofluorescence studies revealed that eu-actinin is localized at the Z-line of myofibrils. The FITC-conjugated antibody to eu-actinin also stained the Z-lines of rabbit skeletal muscle and chicken cardiac muscle. Therefore, it was concluded that eu-actinin is a new, ubiquitous constituent of Z-lines of striated muscles.     

Three dimensional organization of mammalian adrenal cortex

Summary The adrenal cortex of different mammals was studied by SEM in order to demonstrate its actual three-dimensional organization. In the rat, as well as in the cat and pig, the adrenal cortex appeared as a tunnelled continuum of polyhedral cells arranged in plate-like structures (laminae). This laminar arrangement was more evident in the inner fasciculate and reticular zones where the cortex revealed a striking similarity to liver tissue. The polyhedral cells of all cortical zones possessed regular facets populated by small pits, larger invaginations and numerous microvilli with the exception of very short and smooth areas probably corresponding to attachment zones and/or gap junctions. This cellular architecture produced a labyrinthic system of intercellular channels or lacunae in which the capillaries were suspended.The pericapillary areas of this labyrinth contained microvilli, amorphous material, a delicate net of fibrils and occasional cells. The intercellular compartment of this lacunar system was mainly bordered by numerous microvilli arising from endocrine cells.The luminal surface of the capillary wall showed not only irregularly protruding margins (interpretable as endothelial junctions) but also clearly overlapping and flattened endothelial extensions.In all the animals and areas of the adrenal cortex examined, the endothelial wall was provided with abundant clusters of small fenestrations (about 50 nm in diameter) generally arranged in sieve plates. Larger fenestrations were noted mainly in the fasciculate and reticular zones of the cat and pig and occasionally in the rat.A final point related to the nature and significance of sinusoidal fenestrations was the occurrence of irregularly shaped and intracapillary located cells mainly noted in the deeper zones of the fasciculate and reticular zones of the gland. These elements — possessing the surface characteristics of macrophages — were observed, with their irregular and slender evaginations, in close proximity to the large fenestrations in a manner reminiscent of Kupffer cells within the lumen of liver sinusoids.     

Phototaxis in Cryptomonas sp. under condition suppressing photosynthesis

Effects of 3-(3, 4-dichlorophenyl)-l, 1-dimethylurea (DCMU)on photosynthetic oxygen evolution, respiratory oxygen uptake,phototactic response and swimming rate in Cryptomonas sp. weredetermined and compared. Photosynthetic oxygen evolution wascompletely inhibited in the presence of 10^–5 M DCMU. Thetreatment did not significantly affect the rates of respiratoryoxygen uptake, phototaxis, and swimming, indicating that directparticipation of photosynthesis in the phototaxis of this algacan be ruled out. Wavelength dependency of photosynthetic oxygen evolution wasalso determined in the range of 560 to 700 nm. The rate of photosyntheticoxygen evolution at 680 nm was as high as that at 560 nm, butno phototactic activity was seen at 680 nm although it was maximumat 560 nm. This is consistent with the above conclusion. (Received February 16, 1976; )     

Stereoselective synthesis of 5-O-carbamoylpolyoxamic acid (2-amino-5-O-carbamoyl-2-deoxy-l-xylonic acid

One of the constituents of polyoxin J, 2-amino-5-O-carbamoyl-2-deoxy-l-xylonic acid (3), has been synthesized stereoselectively from l-sorbopyranose. The amino acid function of 3 was formed in the final stage of the synthesis by reduction of the corresponding α-azido carboxylic acid.     

Arabinosylnucleoside 5'-triphosphate inhibits DNA primase of calf thymus

It has been shown that DNA primase activity is tightly associated with 10S DNA polymerase alpha from calf thymus and that the ribonucleotide-dependent DNA synthesis is more sensitive to araCTP than DNA-primed DNA synthesis (Yoshida, S., et al. (1983) Biochim. Biophys. Acta 741, 348-357). Here we measured DNA primase activity using poly(dT) template or M13 bacteriophage single-stranded DNA template and primer RNA synthesis was coupled to the reaction by Escherichia coli DNA polymerase I Klenow fragment. By this method, the primer RNA synthesis can be measured independently of the associating DNA polymerase alpha. Using poly(dT) template, it was found that arabinosyladenine 5'-triphosphate (araATP) strongly inhibited DNA primase in competition with rATP. The apparent Ki for araATP was 21 microM and the ratio of Ki/Km (for rATP) was as low as 0.015. With poly(dI, dT) or M13 DNA, it was shown that araCTP also inhibited DNA primase in the similar manner. Product analysis using [alpha-32P]rATP showed that araATP inhibited the elongation of primer RNA. However, it is not likely that arabinosylnucleotides act as chain-terminators, since incubation of primer RNA with araATP did not abolish its priming activity. From these results, it is suggested that arabinosylnucleotide inhibits the initiation as well as elongation of Okazaki fragments in mammalian cells.