Gap characteristics and gap regeneration in primary evergreen broad-leaved forests of western Japan

Gap characteristics and regeneration in gaps were studied in some primary evergreen broad-leaved forests of the warm temperate zone in western Japan. Total observed 161 gaps covered 15.7% of the total land area of 8.23 ha. Gap density was 19. 6 gaps ha⁻¹ and mean gap size was 80.3 m². Smaller gaps (<80 m²) were much more frequent than larger ones, and gaps larger than 400 m² were rare. Gaps created by the death or the injury of single trees were 79.5%. Canopy trees died most often with broken trunks and not so often by uprooting or leaving standing-dead. Different types of gap regeneration behaviour were recognized among the major canopy tree species, though gap regeneration of the common evergreen broad-leaved tree species did not clearly depend on a species-specific gap size.Distylium racemosum, which occurred in equal importance (about 25%) in the canopy layer of each study stand, regenerates in gaps from saplings recruited before gap creation and can replace not only its own gaps but also gaps of other species. Therefore, it can be considered a typical climax species in this forest type of western Japan.Persea thunbergii, which can reproduce vegetatively, showed a similar type of gap regeneration behaviour.Castanopsis cuspidata can replace itself with relatively higher frequency by means of vegetative reproduction (stump sprouting) after gap creation.Quercus acuta andQuercus salicina did not regenerate under the current gap-disturbance regime. Though the frequency of uprooting is low, soil disturbance by uprooting seems to be important for the perpetuation of the pioneer tree species,Fagara ailanthoides, which recruits from buried seeds in the soil     

Seasonal occurrence and food habits of larvae and juveniles of two temperate basses in the Shimanto estuary,Japan

Larvae and juveniles ofLateolabrax japonicus andL. latus occurred from January to May 1986 in the shallow waters of the Shimanto estuary.L. japonicus markedly outnumberedL. latus. Distinct ecological differences were recognized in habitats and food habits between the two species:L. japonicus mainly inhabited eelgrass beds composed ofZostera nana, whileL. latus appeared evenly in both eelgrass beds and non-eelgrass habitats; the former fed on copepods and cladocerans, while the latter fed on copepods and fish larvae. From these habitat and food habit analyses, estuaries were considered to be important as a main habitat forL. japonicus, but not forL. latus. The fact that ecological differences have occurred during the early life stages was inferred to be one of the possible keys to speculate on the speciation of the two species.     

Biphasic activation of cytosolic free calcium and LH responses by gonadotropin-releasing hormone

Gonadotropin-releasing hormone (GnRH) stimulates rapid peak increases in [Ca2+]i and LH release, followed by lower but sustained elevations of both [Ca2+]i and hormone secretion. Omission of extracellular Ca2+ only slightly decreased the peak of [Ca2+]i, but reduced the peak LH response by 40% and prevented the prolonged increases in [Ca2+]i and LH release. Dihydropyridine calcium antagonists did not affect the peak [Ca2+]i and LH responses, but reduced the sustained increases by up to 50%. Whereas GnRH-induced mobilization of intracellular calcium initiates the LH peak, and Ca2+ entry through dihydropyridine-insensitive channels contributes to the peak and plateau phases of LH release, dihydropyridine-sensitive L-type Ca2+ channels participate only in the sustained phase of gonadotropin secretion.     

Inhibitors of sterol synthesis. 14 alpha-ethyl-5 alpha-cholest-7-ene-3 beta,15 alpha-diol induces changes in the sterol composition and the morphology of CHO-K1 cells

Incubation of CHO-K1 cells in lipid-deficient medium containing 14 alpha-ethyl-5 alpha-cholest-7-ene-3 beta,15 alpha-diol (0.1 microM) for 4 days was associated with a profound change in cellular sterol composition as reflected by a marked accumulation of lanosterol and 24,25-dihydrolanosterol. A striking elongation of the cells was also observed. Incubation of CHO-K1 cells in lipid-deficient medium containing lanosterol (10 microM) also caused a significant accumulation of lanosterol which was also associated with a marked elongation of the cells.     

Maple syrup urine disease: a possible biochemical basis for the clinical heterogeneity

Summary Nine patients with maple syrup urine disease (MSUD), of whom eight were detected by mass-screening of neonates for inherited metabolic desease, were studied to determine possible relationships between clinical features and properties of the branched-chain -keto acid dehydrogenase complex (BCKDH) in cultured lymphoblastoid cells. Based on their tolerance for leucine and on the clinical manifestations observed after 2 years of age, most could be classified into three types; classical (tolerate less than 600 mg of leucine per day, N=2), intermediate (N=3) and intermittent (N=3) types. In the other patient two of these three phenotypes were present. The BCKDH activities measured at a lower -ketoisovaleric acid concentration (0.054 mM) were 0.026±0.015 in classical, 0.118±0.016 in intermediate and 0.625±0.139 in intermittent types and 7.052±0.779 (nmol/h per milligram of protein) in two controls, respectively; the differences being statistically significant (P<0.01, classical vs intermediate types; P<0.01, intermediate vs intermittent types; P<0.01, intermittent vs control). Kinetic and immunochemical analyses of the BCKDH revealed that, although there are a few exceptions, classical, intermediate and intermittent types correspond to the enzyme properties of sigmoidal kinetics with E₁ subunit deficiency, near-sigmoidal kinetics with E₁ subunit deficiency and hyperbolic kinetics with E₂ subunit deficiency of the BCKDH, respectively.     

On the clinical usefulness of a few sugar antigens and a galactosyl-transferase

Using human cultured cell lines or lymphocytes, two kinds of murine- and one human-monoclonal antibodies were produced, respectively and their clinical usefulness were investigated, and the possibility of galactosyl-transferase as a new tumor maker was also discussed. (1) A murine monoclonal antibody MSN-1, which was raised against human endometrial cancer cell line and recognized blood type sugar chain Leb, reacted with about 85% of endometrial cancer tissues, indicating that useful clinical information may be obtained by applying MSN-1 to immunohistochemistry and flow cytometry. (2) A new assay system using two murine monoclonal antibodies MA54 and MA61, which were raised against human lung cancer cell line and reacted with mucin sugar residues, revealed 76% positive rate in ovarian cancer patients, especially 82% in mucinous cystadenocarcinoma, indicating the clinical effectiveness as a new tumor maker compensating for the drawbacks of CA-125. (3) Galactosyl-transferase isozyme GT-2 was analyzed by the assay system using a newly produced monoclonal antibody. GT-2 was positive in 74% of ovarian cancers, especially in 89% of meso-nephroid cancer, indicating that GT-2 could be a useful tumor maker in ovarian tumors. (4) Human monoclonal antibody, which recognized "type 1 sugar chain" or iso-paragloboside, reacted about one half of endometrial cancer tissues. The production of human monoclonal antibody may contribute to the cancer imaging and the missile therapy.