bluuebunny/crossref_metadata_2025 huggingface dataset:
Thiol reagents and nitric oxide modulate the gating of BKCa channels from the guinea‐pig taenia caeci
Authors: Lang RJ , Harvey JR
Published: March 2003

1. The site of the direct modulation of the gating of BKCa channels by the nitric oxide donor s‐nitroso‐l‐cysteine (NOCys) was examined in excised membrane patches of the guinea‐pig taenia caeci by the use of various thiol (sulphydryl)‐specific reagents, including N‐ethylmaleimide (NEM) and three charged methanethiosulphonate (MTS) reagents, namely positively charged 2‐aminoethyl MTS hydrobromide (MTSEA) and [2‐(trimethylammonium)ethyl] MTS bromide (MTSET) and negatively charged sodium (2‐sulphonatoethyl) MTS (MTSES), which all specifically convert sulphydryls to a disulphide.

2. At 10 µmol/L, NOCys transiently increased the probability of opening (N.Po) of the BKCa channels (at 0 mV) after a delay of 1–2 min.

3. Disulphide‐reducing agents, such as dithiothreitol (10 µmol/L), increased N.Po in a manner that was reversed by the sulphide‐oxidizing agent thimerosal (10 µmol/L). Both positively charged MTSET (2.5 mmol/L) and negatively charged MTSES (2.5 mmol/L) rapidly increased N.Po. However, only the MTSES‐evoked increase in N.Po remained after a prolonged washout period.

4. The specific alkylating agent of cysteine thiols NEM (1 mmol/L) and the positively charged, but membrane permeable, MTSEA (2.5 mmol/L) decreased N.Po (at 0 mV).

5. Pre‐exposure of excised membrane patches to NEM or MTSES prevented the excitatory actions of NOCys (10 µmol/L).

6. We conclude that MTSES and NOCys must modify thiols on cysteine residues within basic regions of the channel protein that would electrostatically exclude MTSEA and MTSET. A consensus sequence of various mammalian α‐subunits of the BKCa channel reveals two pairs of cysteine residues surrounded by basic amino acids that could be the site of action for NOCys and MTSES.
Transforming growth factor‐β1 does not relate to hypertension in pre‐eclampsia
Authors: Hennessy A , Orange S , Willis N , Painter DM , Child A , Horvath JS
Published: March 2003

1. Pre‐eclampsia is a human disease of pregnancy characterized by high blood pressure, proteinuria and end‐organ damage, if severe. Pre‐eclampsia is thought to be related to changes in early placental development, with the formation of a shallower than normal placental bed.

2. Transforming growth factor (TGF)‐β1 is a multifunctional fibrogenic growth factor involved in immune regulation that is elevated in some populations with a high risk of hypertensive end‐organ disease related to increases in endothelin release. Transforming growth factor‐β1 is also an important factor in placental implantation. Alterations in TGF‐β1 may be related to abnormal placental development in early pregnancy and, thus, are a candidate for the development of hypertension in pre‐eclampsia.

3. The aim of the present study was to examine the placental distribution and serum concentration of TGF‐β1 in patients with pre‐eclampsia compared with normal pregnancy.

4. Patients with pre‐eclampsia (n = 12) were compared with patients with normal pregnancy (n = 14). Transforming growth factor‐β1 was determined by TGF‐β1 Max ELISA (Promega, Madsion, WI, USA) after serum dilution (1/150) and acid activation. Placental distribution was determined by immunostaining with TGF‐β1 (Santa Cruz, Santa Cruz, CA, USA; 20 ng/mL) and the villi and decidual trophoblast were scored for intensity and extent of staining.

5. Patients with pre‐eclampsia had a mean gestational age of 36 weeks, whereas those with a normal pregnancy had a mean gestational age of 39.0 ± 0.4 weeks. There was no difference in TGF‐β1 concentration between the two groups (mean (±SEM) 27.1 ± 1.0 vs 26.4 ± 0.7 pg/mL for normal pregnancy and pre‐eclampsia, respectively; P = 0.73, Mann–Whitney U‐test). There was no correlation between systolic or diastolic blood pressure and TGF‐β1 concentration (regression analysis P = 0.4 and 0.2). Immunostaining was absent in the villous trophoblast cells and endovascular and extravillous trophoblast of term placentas.

6. Although TGF‐β1 is present in trophoblast cells in early pregnancy during placental development, TGF‐β1 concentrations were not increased in the placenta at term in pre‐eclampsia and there was no correlation between blood pressure and serum TGF‐β1, suggesting that TGF‐β1 does not play a role in the development of late gestation pre‐eclampsia and hypertension.
Intracerebral microdialysis: 30 years as a tool for the neuroscientist
Authors: Bourne James A
Published: March 2003

1. Microdialysis is an established technique for studying physiological, pharmacological and pathological changes of a wide range of low molecular weight substances in the brain extracellular fluid. Many studies have proven its sensitivity in sampling the extracellular space in discrete brain locations, such as the striatum, and monitoring the action of exogenous substances.

2. The two main areas of application of microdialysis are the recovery of endogenous substances, primarily the neurotransmitters, and the infusion of drugs through the microdialysis cannula (retrodialysis).

3. Microdialysis in awake animals is the tool of choice for studying the relationship between changes in behaviour and neurotransmitters in certain brain areas. In addition, the concomitant recording of the electroencephalogram at the site of microdialysis has been shown to be extremely useful in determining the role of certain neurotransmitters in paroxysmal activity.

4. Clinical applications of microdialysis have included monitoring of ischaemic injury, subarachnoid haemorrhage, trauma and epilepsy. With the recent availability of standardized equipment, the use of microdialysis in the neurological clinic is likely to become more common.
Adenosine inhibits N‐type calcium channels at the rat neuromuscular junction
Authors: Schwartz Andrew D , Whitacre Camron L , Lin Yue , Wilson David F
Published: March 2003

1. In earlier studies, it has been reported that under in vitro conditions transmitter release at the rat neuromuscular junction is normally suppressed due to the effect of adenosine release from the isolated tissue. In the present study we wanted to determine whether this action may involve the inhibition of calcium influx through adenosine‐sensitive calcium channels.

2. In order to test this hypothesis, we examined the role of N‐type calcium channels in regulating nerve‐evoked transmitter release by using the N‐type calcium channel‐specific blocker ω‐conotoxin GVIA (CTX). In order to control the inhibitory action of adenosine, we also used the adenosine A1 receptor antagonist 1,3‐dipropyl‐8‐cyclopentylxanthine (DPCPX). We tested the effect of blocking N‐type calcium channels with CTX in the presence and absence of DPCPX. We examined the effects of these drugs on quantal transmitter release in the transected preparation of the phrenic nerve–hemidiaphragm of the rat using intracellular recording techniques.

3. At 10 nmol/L, CTX alone had no effect on nerve‐evoked transmitter release; however, in the presence of 0.1 µmol/L DPCPX, CTX significantly depressed nerve‐evoked transmitter release.

4. These data support the view that adenosine inhibits nerve‐evoked transmitter release by inhibiting N‐type calcium channels on nerve terminals.
SM37, a skeletogenic gene of the sea urchin embryo linked to the SM50 gene
Authors: Lee Youn‐Ho , Britten Roy J. , Davidson Eric H.
Published: March 2003

The genomic DNA region that contains the SM50 gene also included a second gene that appeared to encode another skeletogenic matrix protein. The two genes were linked at a distance of about 12 kb. Based on the molecular weight of the implied protein the gene was termed SM37. The SM37 protein included a long tandem sequence of short glycine‐rich repeats that was similar to the glycine‐rich repeats included in the SM50 protein and several other skeletal matrix proteins, although the sequence of SM37 repeat was distinct. The overall structure of the SM37 protein was similar to SM50 as well. However, SM37 was only about 30% identical in amino acid sequence to SM50, and coding region probes behaved as a single copy sequence under standard conditions. The SM37 gene included the same cis‐regulatory elements as the SM50 gene, although in a different order with respect to transcription. This gene was regulated coordinately with SM50 during development, and like SM50 was expressed exclusively in skeletogenic mesenchyme lineages.
Delocalization of polar plasm components caused by grandchildless mutations, gs(1)N26 and gs(1)N441, in Drosophila melanogaster
Authors: Iida Takako , Kobayashi Satoru
Published: March 2003

Two maternal‐effect grandchildless (gs) mutations of Drosophila melanogaster, gs(1)N26 and gs(1)N441, cause delay in nuclear arrival at the polar plasm. In mutant embryos, polar plasm loses its ability to induce pole cells during retarded nuclear migration to the posterior pole of embryos. In the present study, it was shown that in N26 and N441 embryos, mitochondrial large rRNA (mtlrRNA), an essential factor for pole cell formation, is delocalized during the delay in nuclear arrival. This suggests that the loss of mtlrRNA causes failure of the mutants to form pole cells. Furthermore, it was shown that all of the other polar plasm components examined, namely Vasa protein, Germ cell‐less protein, nanos mRNA and Polar granule component RNA start to be delocalized during the delay in nuclear arrival. This suggests that polar plasm integrity is not maintained in mutant embryos. It was finally shown that Vas is also delocalized in embryos that are inhibited to form pole cells by reducing the amount of mtlrRNA. This indicates that the segregation of polar plasm into pole cells is required to maintain polar plasm integrity. The mechanism regulating polar plasm integrity in embryos is discussed.
Establishment of pigment cell lineage in embryos of the sea urchin, Hemicentrotus pulcherrimus
Authors: Kominami Tetsuya
Published: March 2003

In an attempt to estimate the number of pigment precursor cells in sea urchin embryos, DNA synthesis and cell divisions were blocked with aphidicolin from various stages of development. Interestingly, pigment cells differentiated on a normal time schedule, even if the embryos were treated from late cleavage stages on. In most of the embryos treated from 10 h on, 10–15 pigment cells differentiated. Thereafter, the number of pigment cells in the aphidicolin‐treated embryos further increased, as the initiation of the treatment was delayed. On the other hand, total cell volumes in the pigment lineage, calculated from the averaged number and diameter of differentiated pigment cells, were almost the same irrespective of the time of the initiation of aphidicolin treatment. This indicated that the increase in the number was caused by divisions of the pre‐existing cells in the pigment lineage. Thus, the founder cells that exclusively produce pigment cells could be identified. They are nine times‐cleaved blastomeres and specified by 10 h post‐fertilization. The obtained results also clarified the division schedule in the pigment lineage; the founder cells divide once (10th) until hatching, and divide once more (11th) by the end of gastrulation.
Lipid dynamics in the embryos of Patiriella species (Asteroidea) with divergent modes of development
Authors: Byrne Maria , Cerra Anna
Published: March 2003

Evolution of lecithotrophic development in sea stars involved a modification in maternal provisioning from the production of yolk‐dominated to lipid‐dominated eggs. The dynamics of lipid reserves in the embryos of four Patiriella species differing in their lipid provisions were examined. Patiriella regularis had small yolk protein‐dominated eggs (150 μm in diameter) and an ancestral mode of development through planktotrophic larvae. Patiriella calcar, Patiriella exigua and Patiriella pseudoexigua had large eggs (390–440 μm in diameter) and lecithotrophic planktonic, benthic and intragonadal larvae, respectively. Patiriella exigua deposited negatively buoyant eggs containing substantial yolk protein and lipid reserves onto the substratum. In contrast, the planktonic eggs of P. calcar and the intragonadal eggs of P. pseudoexigua were dominated by lipid and were neutrally and positively buoyant, respectively. By the blastula stage there was little trace of lipid in P. regularis embryos. Blastulae of the lecithotrophic developers, by contrast, had conspicuous lipid droplets distributed through their cells. In parallel with the change from cuboidal to columnar epithelium during the blastula to gastrula transition, lipid reserves became redistributed into the basal cytoplasm. The extent of lipid transport reflected the amount of lipid reserves. In P. pseudoexigua embryos with the greatest lipid load, basal shunting was followed by secretion of lipid into the blastocoele where it was stored for the perimetamorphic period. Evolution of lecithotrophy in Patiriella appears to reflect selection to provide metamorphic stages with nutrients normally accrued by feeding larvae with the consequence that early development is burdened by voluminous, potentially inert nutritive stores. Lipid redistribution coincident with a major developmental stage transition may be required to facilitate unimpeded morphogenesis. This phenomenon may be characteristic of lecithotrophic development in echinoderms and appears pre‐adaptive for extrusion of lipid in species like P. pseudoexigua with particularly extensive lipid reserves.
Regulative specification of ectoderm in skeleton disrupted sea urchin embryos treated with monoclonal antibody to Pl‐nectin
Authors: Zito Francesca , Nakano Eizo , Sciarrino Serafina , Matranga Valeria
Published: March 2003

Pl‐nectin is a glycoprotein first discovered in the extracellular matrix (ECM) of Paracentrotus lividus sea urchin embryo, apically located on ectoderm and endoderm cells. The molecule has been described as functioning as an adhesive substrate for embryonic cells and its contact to ectoderm cells is essential for correct skeletogenesis. The present study was undertaken to elucidate the biochemical characteristics of Pl‐nectin and to extend knowledge on its in vivo biological function. Here it is shown that the binding of mesenchyme blastula cells to Pl‐nectin‐coated substrates was calcium dependent, and reached its optimum at 10 m
M Ca2+. Perturbation studies using monoclonal antibody (McAb) to Pl‐nectin, which prevent ectoderm cell‐Pl‐nectin contact, show that dorsoventral axis formation and ectoderm differentiation were retarded. At later stages, embryos recovered and, even if growth and patterning of the skeleton was greatly affected, the establishment of dorsoventral asymmetry was reached. Similarly, the expression of specific ectoderm and endoderm territorial markers was achieved, although occurring with some delay. Endoderm differentiation and patterning was not obviously affected. These results suggest that both endoderm and ectoderm cells have regulative capacities and differentiation of territories is restored after a lag period. On the contrary, failure of inductive differentiation of the skeleton cannot be rescued, even though the ectoderm has recovered.
Sex reversal of germ cell gametogenesis in chimeras of Pleurodeles waltl (urodele amphibian): Genetic and immunogenetic demonstration using tolerance or rejection of skin grafts
Authors: Dournon Christian , Membre Hervé , Bautz Alain
Published: March 2003

Viable chimeras were constituted with two cranial and caudal complementary pieces of embryos derived from two distinct histocompatible AA and BB strains, which were incompatible with each other. The embryonic gonads of the resulting chimeras constituted two homo‐ or heterosexual territories. In most heterosexual chimeras, the testicular territory sex reversed the ovarian territory. The offspring analysis of a male chimera conclusively proved that ZW germ cells derived from the posterior female piece differentiated into spermatozoa. Nevertheless, the opposite situation was also demonstrated with a female chimera in which ZZ germ cells derived from the anterior male piece differentiated into oocytes. These gametogenesis reversions were tested by genetic and immunogenetic analyses of chimera offspring. The phenomenon of tolerance or rejection of skin allo‐ and autograft was used as a marker of origin of the chimera germ cells, which had produced the offspring. Moreover, in the first stage of the study, the origin of the pieces of adult chimeras was determined using skin grafts. During this stage, the embryonic tolerance was confirmed by the acquisition of four pieces of pairs of chimeras, and by the preservation of skin immunogenicity that was derived from each piece of the chimeras.
Subtractive hybridization reveals tissue‐specific expression of ahnak during embryonic development
Authors: Kingsley Paul D. , McGrath Kathleen E. , Maltby Kathleen M. , Koniski Anne D. , Ramchandran Rajeev , Palis James
Published: March 2003

The gene product ahnak has been identified from extra‐embryonic mesoderm cDNA enriched using a subtractive hybridization approach modified for using small amounts of starting material. Clones for cyclin D2 and H19 have also been isolated as being preferentially enriched in the extra‐embryonic mesoderm compared with the embryo proper of embryonic day (E) 7.5 neural plate stage mouse embryos. The differential expression of these genes was confirmed at gastrulation stage using in situ hybridization. More detailed analysis of the human genomic ahnak sequence suggests that its highly repetitive structure was formed by unequal cross‐over and gene conversion. During organogenesis, ahnak is expressed in a variety of tissues, including migratory mesenchyme. By E12.5, the major site of expression of ahnak is craniofacial mesenchyme. Immunohistochemical analysis has shown that ahnak protein is expressed mainly at the cell membrane of migratory mesenchymal cells, primarily in the nucleus of bone growth plate cells and mostly in the cytoplasm of differentiating nasal epithelia. The potential functions of ahnak are discussed in light of these results.
Effects of Ca2+ on flavin‐linked complex enzymes in mitochondria isolated from eggs and embryos of sea urchin
Authors: Fujiwara Akiko , Kamata Yasuyuki , Yasumasu Ikuo
Published: March 2003

Mitochondria isolated from sea urchin embryos in early development show almost the same activities of cytochrome c oxidase and flavin‐linked complex enzymes, which are estimated by cytochrome c reductases as in those isolated from unfertilized eggs. The activities of these cytochrome c reductases are inhibited by Ca2+ at above 10–5M more strongly than cytochrome c oxidase. To investigate the changes in intramitochondrial Ca2+ concentration at fertilization, the activity of pyruvate dehydrogenase, another mitochondrial enzyme, was measured. The activity of this enzyme was controlled by phosphorylation and Ca2+‐dependent dephosphorylation of the catalytic unit. The enzyme activity increased for 30 min after fertilization, decreased and became close to zero within ~60 min. Then, the activity appreciably increased again after hatching. This seems to reflect changes in the intramitochondrial Ca2+ concentration. The enzyme activity was enhanced by pre‐incubation with Ca2+ at concentrations up to 10–5M but was made quite low at above 10–4M Ca2+ and 10–3M adenosine triphosphate. Although the changes in pyruvate dehydrogenase activity observed at fertilization will reflect the changes in the intramitochondrial calcium concentration, the intramitochondrial Ca2+ concentration of unfertilized eggs cannot be estimated from these results because high (> 10–4M) or low (10–6M) Ca2+ can inhibit the enzyme. Measurement of respiration of a single egg showed that injection of ethyleneglycol‐bis(β‐aminoethyl ether)‐N,N,N′,N′‐tetraacetic acid released the mitochondrial electron transport in the unfertilized egg. The possibility that changes in intramitochondrial calcium concentration occur at fertilization is discussed in relation to activation of both mitochondrial respiration and pyruvate dehydrogenase.
Left–right asymmetry in Drosophila melanogaster gut development
Authors: Hayashi Tomomi , Murakami Ryutaro
Published: March 2003

While left–right (LR) asymmetric morphogenesis is common to various animal species, there have been no systematic studies of the LR asymmetry of body structures of Drosophila melanogaster. In the present paper the LR asymmetric development of the Drosophila gut is described, in which three major parts, the foregut, midgut and hindgut, show almost invariant LR asymmetry. The asymmetry is generated by a twist of each part in particular orientations, resulting in a left‐handed (sinistral) convolution as a whole. The frequency of spontaneous reversal of LR orientations is very low (< 0.6%) and reversal of each part of the gut occurs independently. The bicoid mutation causes duplication of the posterior half of the gut, essentially keeping the left‐handed twist, suggesting that the LR asymmetry may depend on some intrinsic nature of the cells or tissues rather than a graded distribution of morphogens in the egg. The handedness of particular gut parts was randomized or became symmetric in mutants of brachyenteron, huckebein and patched, suggesting that different gene pathways can interfere in determining LR asymmetry of the gut. It is noteworthy that all of these genes are expressed LR symmetrically.
Upregulation of cellular retinoic acid‐binding protein I expression by ethanol
Authors: Bi Jing , Hu Xinli , Zhou Feng C. , Wei Li‐Na
Published: March 2003

Acute and chronic ethanol ingestion cause embryopathy similar to that of hyper‐ or hypovitaminosis A. Experimental data have suggested interaction between vitamin A and alcohol signaling pathways at the level of metabolic interference, which ultimately affects the concentration of retinoic acid (RA) in animals. The present study was set up to examine the possible effects of alcohol on cellular RA binding protein I (CRABP‐I) expression during embryonic development by using transgenic mouse embryos and P19 embryonal carcinoma cells as experimental models. It was found that expression of the mouse CRABP‐I gene was elevated in developing embryos at mid‐gestation stages as a result of ethanol consumption by the mothers. Specific elevation of this gene was detected in the limb bud and the gut. In the P19 model, the CRABP‐I gene was directly upregulated by ethanol, which was not blocked by a protein synthesis inhibitor. Furthermore, the regulation of the CRABP‐I gene by ethanol was mediated by the 5′ upstream regulatory region of the CRABP‐I gene promoter. A potential interaction of vitamin A and ethanol at the level of CRABP‐I gene expression is discussed.
In the multiheaded strain (mh‐1) of Hydra magnipapillata the ectodermal epithelial cells are responsible for the formation of additional heads and the endodermal epithelial cells for the reduced ability to regenerate a foot
Authors: Zeretzke Stefanie , Berking Stefan
Published: March 2003

Hydra consist of three self‐renewing cell lineages: the ectodermal epithelial, endodermal epithelial and interstitial cell lineages. The role of these cell lineages in head formation and foot regeneration in Hydra magnipapillata was studied by comparing the multiheaded strain mh‐1 with the wild‐type. Adult polyps of this strain show a reduced ability to regenerate a foot in the apical body half several days before additional heads are formed there. Cell lineage chimeras were produced, and it was found that in mh‐1, the ectodermal epithelial cell lineage is responsible for the formation of additional heads, whereas the endodermal epithelial cell lineage and, to a lesser extent, the derivatives of the interstitial cell lineage, are responsible for the reduced ability of foot regeneration.
In vitro induction of the pronephric duct in Xenopus explants
Authors: Osafune Kenji , Nishinakamura Ryuichi , Komazaki Shinji , Asashima Makoto
Published: March 2003

The earliest form of embryonic kidney, the pronephros, consists of three components: glomus, tubule and duct. Treatment of the undifferentiated animal pole ectoderm of Xenopus laevis with activin A and retinoic acid (RA) induces formation of the pronephric tubule and glomus. In this study, the rate of induction of the pronephric duct, the third component of the pronephros, was investigated in animal caps treated with activin A and RA. Immunohistochemistry using pronephric duct‐specific antibody 4A6 revealed that a high proportion of the treated explants contained 4A6‐positive tubular structures. Electron microscopy showed that the tubules in the explants were similar to the pronephric ducts of normal larvae, and they also expressed Gremlin and c‐ret, molecular markers for pronephric ducts. These results suggest that the treatment of Xenopus ectoderm with activin A and RA induces a high rate of differentiation of pronephric ducts, in addition to the differentiation of the pronephric tubule and glomus, and that this in vitro system can serve as a simple and effective model for analysis of the mechanism of pronephros differentiation.
Conserved expression control and shared activity between cognate T‐box genes Tbx2 and Tbx3 in connection with Sonic hedgehog signaling during Xenopus eye development
Authors: Takabatake Yuka , Takabatake Takashi , Sasagawa Satoru , Takeshima Kazuhito
Published: March 2003

Tbx2 and Tbx3 are considered to be cognate genes within a Tbx2/3/4/5 subfamily of T‐box genes and are expressed in closely overlapping areas in a variety of tissues, including the eye. Herein, we show that misexpression of Tbx2 and Tbx3 in Xenopus embryos gave rise to defective eye morphogenesis, which was reminiscent of the defect caused by attenuated Sonic hedgehog (Shh) signaling. Indeed, Tbx2/3 misexpression suppressed Gli1, Gli2, Ptc2 and Pax2, mediators or targets of Hedgehog (Hh) signals. From these data, Tbx2/3 may have a shared function in inhibiting Gli‐dependent Shh signaling during eye development. Conversely, the expression of Tbx2/3 was severely affected by both Shh and a putative dominant negative form of Hh, as well as by both transactivator and transrepressor forms of Gli‐fusion proteins, suggesting that the expression of Tbx2/3 may be regulated by a Gli‐dependent Hh signal transduction pathway. Because the Shh signal has been considered to play crucial roles in the formation of the proximal–distal and dorsal–ventral axes in the eyes, these findings about the mutual regulatory mechanism between Tbx2/3 and Gli‐dependent Hh signaling provide valuable insight into the cause of the localized expression of Tbx2/3 and their role during the formation of these axes. In addition, our findings also imply the conserved regulation and shared activity between the cognate genes of Tbx2 and Tbx3.
Current state and the future of the crested ibis (Nipponia nippon): A case study by population viability analysis
Authors: Li Xinhai , Li Dianmo
Published: March 2003

There is only one population of the crested ibis (Nipponia nippon) surviving in the wild, which has not exceeded 40 individuals since it was rediscovered in 1981. We used detailed data of the annual population size and natality collected by the Crested Ibis Conservation and Observation Station (CICOS) over the past 17 years. We were able to obtain a more accurate census of age structure and mortality as all of the fledglings have been identified by leg bands in 1987. Consequently, we analyzed the current state of the crested ibis and predicted its future using Population Viability Analysis (PVA) with the help of the computer simulation model VORTEX (Version 7.2). The results indicated that the extinction probability of the crested ibis was 19.7% in 100 years. Sensitivity analysis showed that the extinction probabilities were sensitive to catastrophes and environmental variation, and the long‐term existence of the population was dependent on the carrying capacity of the habitat and inbreeding depression. Conservation efforts are critical for the survival of the crested ibis. The prior conservation project involves controlling hunting and predation, as well as improving the life level of these few remnant creatures.
Contribution of woody debris to trout habitat modification in small streams in secondary deciduous forest, northern Japan
Authors: Urabe Hirokazu , Nakano Shigeru
Published: March 2003

Field studies to examine the influence of woody debris on rainbow trout (Oncorhynchus mykiss) abundance through habitat modification were conducted in two small streams, the Horonai and Uenae streams, running through secondary deciduous forest in south‐western Hokkaido, northern Japan. Reach‐based woody debris volume (total woody debris volume per 100 m2 of study reach) was significantly correlated with the total basal area of riparian stands along the margins of the Horonai stream, but no significant relationship was evident between them for the Uenae stream. This inconsistency between the streams was considered to be a result of the difference in stream size (width, depth and discharge). Woody debris was the principal agent for pool formation, although it had a far smaller volume than that found in streams draining old‐growth coniferous forest in North America, where most of the previous studies have been carried out. Untransported debris pieces of larger volume more effectively contributed to pool formation than smaller transported pieces. The volume of individual debris scour pools was positively correlated with the volume of woody debris associated with each. Similarly, reach‐based pool volume increased with total woody debris volume, but the relationship was less clear in the Uenae stream, having more abundant transported woody debris than the Horonai stream. The biomass of rainbow trout in individual pools, which were regarded as the most preferred habitat type for stream salmonids, was correlated with pool volume. A positive relationship also existed between reach‐based standing crop and pool volume. These results revealed that secondary deciduous forest, like old‐growth coniferous forest, plays an important role in enhancing the carrying capacity for rainbow trout by supplying woody debris which promoted preferred habitat formation.
Aboveground biomass and soil nutrient pools of a Scalesia pedunculata montane forest on Santa Cruz, Galápagos
Authors: Kitayama Kanehiro , Itow Syuzo
Published: March 2003

We estimated the live aboveground biomass (AGB) and soil nutrient pools of the Scalesia pedunculata monodominant tropical montane forest at 600 m above sea level on Santa Cruz, Galápagos, an isolated oceanic island. The estimated AGB was 60.4 Mg ha−1, which was considerably lower than that of other montane forests of similar climates elsewhere. Nutrient pools were ample for inorganic N, soluble P, and exchangeable cations. We suggest that the low AGB, in spite of the ample nutrients, is related to the absence of tall‐statured climax species, that have high demands for nutrients (particularly N) to fix C, due to the isolation.
Organic matter economy of Euphorbia adenochlora with special reference to its life cycle
Authors: YAMASAKI SHIORI
Published: March 2003

The dry matter economy of Euphorbia adenochlora Morra et Decne was investigated in a moist tall grassland in the Tajimagahara nature reserve, which protects a riverside grassland on the Arakawa river in Saitama Prefecture, central Japan. Euphorbia adenochlora is a typical short clonal species in the flood plain meadows, but is listed as an endangered species. It starts to grow in late February, and grows fast in early April by using one‐third to about half of the dry matter of the rhizomes, which are composed of annual segments up to 8–10 years of age. During the period of fastest growth in early April, the bulk density (g dry weight cm−3) of the rhizomes attained the minimum value. By the end of May, it reached its maximum. When 13CO2 was fed to the shoots by means of photosynthesis, the concentration of 13C‐containing photosynthates was highest in the new rhizome segment; the older the segment the lower the concentration of 13C. Shoot‐clipping of E. adenochlora in late April, when bulk density was near the minimum, greatly depressed shoot growth in the following year. At the beginning of June, all of the aerial shoots of E. adenochlora died out with the growth of tall grasses. These results suggest that E. adenochlora has a life cycle as a spring ephemeral.
Effect of millipede Parafontaria tonominea Attems (Diplopoda: Xystodesmidae) adults on soil biological activities: A microcosm experiment
Authors: Kaneko Nobuhiro
Published: March 2003

Effects of high density adult millipede populations on soil ecosystem properties were investigated using laboratory and field microcosm methods in a deciduous broad‐leaved forest in western Japan. The density of Parafontaria tonominea adults was 25.6–72.0 individuals m−2 on 15 September 1996, then the density declined to 0–5.4 m−2 on 22 October 1996. Addition of millipedes to the laboratory microcosm enhanced soil respiration and decreased soil microbial biomass. Soil microcosms with and without millipedes (one and two pairs of adults) were set on a forest floor, and soil respiration, dissolved ion concentration in leacheate water were observed for 8 weeks. The millipedes ingested both leaf litter and soil, which increased soil respiration, leaching of Ca2+, Mg2+, and nitrate from the soil, whereas the soil microbial biomass was not changed at 8 weeks after introduction of the animals. Millipede feeding on soil enhanced microbial activity and nutrient leaching from the forest soil.
Patterns and propensities in reproduction and growth of marine fishes
Authors: Cury Philippe , Pauly Daniel
Published: March 2003

A number of strong regularities characterize certain very basic biological parameters in marine fishes. For example, the ovulated eggs of fish usually measure approximately 1 mm in diameter. The small, relatively uniform size of the eggs means that almost all fish larvae experience environmental variability at very similar scales, which itself establishes strong constraints for, and links between reproduction and recruitment. Additional constraints emerge from seawater being a poor medium for respiration, which establishes further linkages between growth and mortality. These constraints have produced strongly convergent features, and thence the patterns in reproduction and growth of marine fishes that are presented.
Measures of spatial heterogeneity for species occurrence or disease incidence with finite‐counts
Authors: Shiyomi Masae , Yoshimura Jin
Published: March 2003

We propose two types of indices with finite‐count correction to measure the spatial heterogeneity of binary characteristics of organisms, such as occurrence or non‐occurrence of organisms and infected or non‐infected plants. We consider the following two examples: plant occurrence in a grassland community, and yellow dwarf disease infection in a rice field. For the grassland community, N quadrats comprising n cells of equal area, were set at random sites in a grassland, and the occurrence of a given species A in each of n cells was recorded. For disease infection, N quadrats, each consisting of n rice plants, were set at random sites in a paddy field, and the number of plants infected with yellow dwarf virus in each quadrat were counted. In these examples, since the number of cells in a quadrat is finite, neither occurrence nor incidence increase infinitely, unlike the number of aphids on a maize leaf. The first category of index belongs to the mean : variance ratio type. The estimated index value for occurrence (or incidence) is the same as that for non‐occurrence (or non‐incidence). The second category belongs to the k‐type of a negative binomial distribution. If some random plants die or recover from the disease then the expected value of the second type of index does not change. For n→∞, the current indices approach the mean : variance ratio and the inverse of k in a negative binomial distribution, respectively. This indicates that these indices are suitable for binary data sets.
Effects of rodent gnawing on the survival of current‐year seedlings of Quercus crispula
Authors: Sato Toshihiko
Published: March 2003

Emergence, survival and mortality patterns of current‐year oak (Quercus crispula Blume) seedlings were investigated for 4 consecutive years in a secondary oak forest in Hokkaido, northern Japan. Despite the emergence of a considerable number of oak seedlings in the years following masting, few current‐year seedlings survived until the end of the growing season. Almost all of the seedlings died from damage to their stems caused by the gnawing of rodents. Rodent gnawing on transplanted oak seedlings was also observed in the year following masting but not in the year following a bad crop year. Cuttings of dwarf bamboo, Sasa, did not reduce the seedling mortality caused by gnawing. However, transplanted oak seedlings were gnawed more quickly when they were placed on the forest floor with a thicker Sasa covering. All rodents trapped in the vicinity of the study area were Apodemus speciosus Temminck. These results suggest that rodents strongly influence the recruitment of oak trees not only through the predation and dispersal of acorns but also through gnawing seedlings.
Diurnal changes in needle gas exchange in alpine Pinus pumila during snow‐melting and summer seasons
Authors: Ishida Atsushi , Nakano Takashi , Sekikawa Seikoh , Maruta Emiko , Masuzawa Takehiro
Published: March 2003

Pinus pumila (Pallas) Regel. is a dominant dwarf tree in alpine regions of Japan. The possible factors limiting the net photosynthetic rate (Pn) of the needles of P. pumila were examined in the snow‐melting (May) and the summer (August) seasons. In August, in situ maximum Pn was 20 μmol kg−1 needle s−1 in the current‐year needles and 25 μmol kg−1 needle s−1 in the 1‐year‐old needles. Diurnal trends of Pn in August were positively related to fluctuations in photosynthetic photon flux density (PPFD) and no midday depression of Pn was found, indicating that a decrease in PPFD rather than an increase in needle‐to‐air vapor pressure deficit (ΔW) might cause the reduction of Pn. Both stomatal conductance (gs) and Pn were lower in May than in August. In May, Pn and gs were almost zero in the morning, but gradually increased with decreasing ΔW, reaching maximum Pn values (4 μmol kg−1 needle s−1) and gs (60 mmol kg−1 needle s−1) at 16.00 hours. The daytime Pn in May was positively related to gs. Relative water content in the exposed needles above the snow in May was 83%, which was far above the lethal level. This indicates that the water flow from stems or soils to needles was enough to compensate for a small amount of water loss due to the low gs in May, although the water supplied to needles would be impeded by the low temperatures. Thus, the reduced gs in May would be important for avoiding needle desiccation, and would result in a reduced Pn.
Hoarding behaviors of two wood mouse species: Different preference for acorns of two Fagaceae species
Authors: Shimada Takuya
Published: March 2003

Two species of wood mouse, Apodemus argenteus and A. speciosus, were observed consuming and hoarding acorns of Quercus serrata and Castanopsis cuspidata. When each species of acorn was supplied individually, both species of mice used each species of acorn for eating and hoarding. When both species of acorn were supplied, A. argenteus consumed or hoarded only C. cuspidata, whereas A. speciosus tended to eat C. cuspidata acorns at the feeding site, and disperse or hoard Q. serrata acorns. Apodemus speciosus is unlikely to disperse C. cuspidata acorns (their utilization was biased towards consumption) when Q. serrata acorns are also available. Apodemus argenteus will make almost no contribution to the dispersal of Q. serrata when the two acorn species coexist.
Liana diversity and host relationships in a tropical evergreen forest in the Indian Eastern Ghats
Authors: Chittibabu C. V. , Parthasarathy N.
Published: March 2003

In tropical evergreen forest in the Kolli Hills of the Indian Eastern Ghats, four 2 ha (100 m × 200 m) replicate plots (two plots each in undisturbed and human‐impacted sites), were inventoried for species diversity of lianas ≥5 cm girth at breast height (g.b.h.) and their relationships with ≥30 cm g.b.h. host trees. Liana diversity included 26 species from 18 families and 24 genera. The population density and basal area of lianas in the study plots were 48 individuals ha−1 and 0.23 m2 ha−1, respectively, while those of the trees were 478 stems ha−1 and 43.6 m2 ha−1, respectively. As the lianas and their hosts had often been cut in the disturbed sites, their diversity was less there than in the undisturbed sites. Five (19%) liana species were common to all four sites. Three lianas, Hiptage benghalensis (Malpighiaceae), Elaeagnus indica (Elaeagnaceae) and Gnetum ula (Gnetaceae) were dominant. The twining mechanism (54% of liana species and 71% of individuals) and zoochorous diaspores (73% of species and 77% of individuals) predominated. A total of 336 trees from 39 species, 34 genera and 22 families hosted 345 lianas. The ratio of liana : host for species was 1 : 1.5 and for individuals was 1 : 1. Liana preferences for certain host trees, host girth classes and trellis heights were evident.
Effects of clear‐cutting and burning on characteristics of nitrogen mineralization and microbes in the forest soil of a Pinus massoniana plantation in Southern China
Authors: Liu Famao , Toda Hiroto , Haibara Kikuo
Published: March 2003

The aim of this study was to clarify the effects of clear‐cutting and burning (CCB) on soil fertility in a Pinus massoniana (Masson pine) plantation after CCB in Fujian Province, China. We investigated changes in nitrogen (N) mineralization potential (N0), N mineralization rate constant (k) and the apparent activation energy (Ea) of the soil, with a mathematical analysis using a kinetics model based on the results of in vitro incubation. Changes in the amount of microbial biomass nitrogen (MBN), as well as the number of heterotrophic and nitrite‐oxidizing bacteria, were also investigated. The N0, MBN and the number of fungi and actinomycetes in forest soil was reduced for at least 18 months after CCB. The number of heterotrophic and nitrite‐oxidizing bacteria increased, and k, Ea and N mineralization became greater after 6 months of CCB, compared with the control plots. Because there were few young trees planted, which would have taken up mineralized N in the post‐CCB site, it is probable that a high proportion of the mineralized N that accumulated in the soil may have been lost during the summer rainy season. Therefore, it is suggested that CCB led to a deficiency in available N during short rotations, which resulted in soil degradation.
Relation between age–sex classes and dietary selection of wild Japanese monkeys
Authors: Agetsuma Naoki
Published: March 2003

Dietary selection by wild Japanese monkeys (Macaca fuscata yakui Kuroda) was examined in relation to body size. The monkeys were classified into three age–sex categories: adult males, adult females and immatures excluding suckling infants. Time spent feeding did not differ between age–sex classes, although time spent moving was longer in lighter classes. Heavier individuals fed relatively more on mature leaves, while lighter individuals fed on insects more frequently. Mature leaves were more abundant but had lower energy content than other food items in the forest. Heavier monkeys seemed to feed on greater amounts of lower quality food in this species. This finding agrees with the Jarman–Bell principle on ungulates.
Functional succession of bacterioplankton on the basis of carbon source utilization ability by BIOLOG plates
Authors: Matsui Kazuaki , June Man‐Sig , Ueki Masaya , Kawabata Zen’ichiro
Published: March 2003

Changes of bacterioplankton diversity in lake water were followed in triplicate, continuous‐flow experimental tanks. Most probable numbers (MPN) were obtained for 95 different carbon sources using BIOLOG plates and were used to characterize bacterioplankton diversity. During 70 days of incubation, MPN declined for 15 of the 95 substrates while three of 95 appeared to be newly used, indicating functional succession in the bacterioplankton. Total bacterial cell abundance was constant from day 7 to day 70 of the incubation period. The succession of species composition of phyto‐ and zooplankton was also observed and suggested some involvement by phyto‐ and zooplankton species in the changes of bacterioplankton diversity. Thus, BIOLOG‐based MPN assays is a simple but sensitive method for characterizing the changes in the bacterioplankton carbon utilization profile and is also useful for tracing the functional succession of bacterioplankton diversity within a community.
Prokaryotic and viral diversity patterns in marine plankton
Authors: Fuhrman Jed A. , Griffith John F. , Schwalbach Michael S.
Published: March 2003

Prokaryotes and viruses play critical roles in marine ecosystems, where they are both highly abundant and active. Although early work on both prokaryotes and viruses revealed little of their diversity, molecular biological approaches now allow us to break apart these ‘black boxes.’ The most revealing methods have been cloning and sequencing of 16S rRNA genes, community fingerprinting (such as terminal restriction fragment length polymorphism; TRFLP), and fluorescent in

situ hybridization. Viral diversity can now be analyzed by pulsed field gel electrophoresis (PFGE) of viral genomes. The present paper summarizes recent advances in bacterial and virus diversity studies, and presents examples of measurements from polar, tropical, and temperate marine waters. Terminal restriction fragment length polymorphism shows that many of the same operationally defined prokaryotic taxa are present in polar and tropical waters, but there are also some unique to each environment. By one measure, a sample from over a Philippine coral reef had about 100 operationally defined taxa, whereas one from the open tropical Atlantic had about 50 and from the icy Weddell Sea, about 60. Pulsed field gel electrophoresis of two depth profiles, to 500 m, from Southern California, measured 2 months apart, shows striking similarities in viral genome length diversity over time, and some distinct differences with depth. The euphotic zone samples had extremely similar apparent diversity, but samples from 150 m and 500 m were different. An obvious next step is to compare the bacterial and viral diversity patterns, because theory tells us they should be related.
How does spittlebug oviposition affect shoot growth and bud production in two willow species?
Authors: Nozawa Akiyoshi , Ohgushi Takayuki
Published: March 2003

We measured the effects of oviposition by the spittlebug Aphrophora pectoralis on shoot growth and bud production in two willow species, Salix miyabeana and Salix sachalinensis. In autumn, adult females of A. pectoralis insert their ovipositor into the apical region of 1‐year‐old shoots, resulting in the death of most shoot tips within 1 week. Consequently, an increase in the number of dead buds and a decrease in the number of vegetative buds on 1‐year‐old shoots was recorded. In the following spring, the growth of current‐year shoots was greatly increased on 1‐year‐old shoots damaged by spittlebug oviposition. Furthermore, spittlebug oviposition increased the production rate of vegetative buds in both S. miyabeana and S. sachalinensis. However, no impact on the production rate of reproductive buds was detected in either willow. We conclude that the compensatory growth of current‐year shoots and an increase in vegetative buds in the two willow species was caused by oviposition of A. pectoralis.