Hydraulic conductivity, photosynthesis and leaf water balance in six evergreen woody species from fall to winter

To confirm that freeze-thaw embolism is a primary stress for evergreen woody species in winter, hydraulic conductivity, photosynthesis and leaf water potential were measured during fall and winter in trees growing in a cool temperate zone (Nikko) and in a warm temperate zone (Tokyo). We examined two evergreen conifers that naturally occur in the cool temperate zone (Abies firma Siebold & Zucc. and Abies homolepis Siebold & Zucc.), and four evergreen broad-leaved woody species that are restricted to the warm temperate zone (Camellia japonica L., Cinnamomum camphora (L.) J. Presl, Ilex crenata Thunb. and Quercus myrsinaefolia Blume). In Tokyo, where no freeze-thaw cycles of xylem sap occurred, hydraulic conductivity, photosynthesis and water balance remained constant during the experimental period. In Nikko, where there were 38 daily freeze-thaw cycles by February, neither of the tracheid-bearing evergreen conifers showed xylem embolism or leaf water deficits. Similarly, the broad-leaved evergreen trees with small-diameter vessels did not exhibit severe embolism or water deficits and maintained CO(2) assimilation even in January. In contrast, the two broad-leaved evergreen trees with large-diameter vessels showed significantly reduced hydraulic conductivity and shoot die-back in winter. We conclude that freeze-thaw embolism restricts evergreen woody species with large-diameter vessels to the warm temperate zone, whereas other stresses limit the distribution of broad-leaved trees, that have small-diameter vessels, but which are restricted to the warm temperate zone.     

Transmission of mitochondrial plasmids in protoplast cell fusion between compatible monokaryons of <Emphasis Type="Italic">Lentinula edodes</Emphasis>

Electrophoretic analysis of the transmission pattern of mitochondrial plasmids in protoplast cell fusion between compatible monokaryons of Lentinula edodes indicates that three of the four plasmids carried in parental monokaryons are effectively transferred and replicated in the protoplast fusants. The two monokaryons, 1158a and 1569a, carried different plasmids that could be distinguished by a single restriction digest. Electrophoresis of intact plasmids and restriction analyses indicate that all but one of the fusants carry three of the four possible plasmids, indicating that transmission of plasmids in protoplast fusions is principally biparental in L. edodes. Thus, heterocytoplasmic cells of L. edodes can be effectively constructed by protoplast cell fusion. In addition, plasmids of the same homology group cannot coexist in the heteroplasmic cells after protoplast cell fusion. Contribution No. 382 of the Tottori Mycological Institute     

Growth pattern analysis and stemwood production in an unmanaged old plantation of hiba, Thujopsis dolabrata, in northern Japan

We analyzed the growth patterns of Thujopsis dolabrata var. hondai trees in an old plantation (161 years old), where no silvicultural treatments (e.g., thinning) have been conducted since the initial planting. The analysis focused on understanding individual growth under a long-term self-thinning process, and the stand-level stemwood production at the mature stage was evaluated. Nine canopy-layer trees and one suppressed tree were used for the analysis of annual increments in stem diameters, heights, and stemwood volumes for a given past year using the ring-width data. Both the diameter (at basal portion) and height of all the canopy-layer trees increased at similar rates during the early stage (i.e., 60–70 years after planting); however, after this period, only the height growth rates declined sharply. The annual growth rates of stemwood volume also simultaneously leveled off at the stand age of 40–60 years. Subsequently, the patterns diverged conspicuously, e.g., the growth rates were maintained or increased in some individuals, while it gradually decreased in the case of others until the present year. The divergence of growth pattern was likely to be triggered by intertree competition at several decades after the onset of canopy closure. The current stemwood production of the sample trees, including the suppressed one, was positively correlated with certain size parameters such as stem diameter at breast height and sapwood area at a height of 4 m. Based on the diameter-base allometry, the total stand stemwood production was estimated to be about 12.8 m³ ha⁻¹ year⁻¹. This estimate was higher than those of some old natural T. dolabrata forests (2.0–8.6 m³ ha⁻¹ year⁻¹) that have been well managed by repetitive selection thinning. Furthermore, individual mean stemwood production of the study plantation (0.03 m³ tree⁻¹ year⁻¹) was within the range of these natural stands (0.01–0.05 m³ tree⁻¹ year⁻¹). These comparisons suggested that the old T. dolabrata plantation still maintained a relatively high stemwood production potential despite the absence of artificial controls of tree density in the past. In terms of timber production, this fact implied that a rather long rotation (>100 years) can be applicable in the management of T. dolabrata plantations.     

Induction of the biosynthesis of agatharesinol, a norlignan, in sapwood sticks of Cryptomeria japonica under humidity-regulated circumstances

To establish an experimental approach for studying the biosynthetic pathway of agatharesinol, a norlignan, induction of the formation of agatharesinol in Cryptomeria japonica (Japanese cedar, sugi) was attempted. Wood sticks were prepared from the sapwood immediately after cutting a sugi tree down, and they were allowed to stand in desiccators in which the humidity was adjusted to 76% and 88%, and in a room. When the wood sticks were allowed to stand in 76% humidity and in a room, they dried rapidly and no formation of agatharesinol was demonstrated by gas chromatography-mass spectrometry. These results suggest that in the sapwood dried rapidly, the cells that were biologically active in the sapwood, probably ray parenchyma cells, die rapidly and completely before the biosyntheses of secondary metabolites including agatharesinol was wholly established. The wood sticks allowed to stand in 88% humidity, on the other hand, dried gradually compared with the sticks placed in 76% humidity and in a room, and agatharesinol was formed as one of the predominant ethyl acetate extractives. These results suggest that delaying the drying of the sapwood sticks can control the dying period to an appropriate length for the ray parenchyma cells, during which the biosynthesis of agatharesinol is induced. Part of this study was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

Production of transgenic cloned pigs expressing the far-red fluorescent protein monomeric Plum

Monomeric Plum (Plum), a far-red fluorescent protein with photostability and photopermeability, is potentially suitable for in vivo imaging and detection of fluorescence in body tissues. The aim of this study was to generate transgenic cloned pigs exhibiting systemic expression of Plum using somatic cell nuclear transfer (SCNT) technology. Nuclear donor cells for SCNT were obtained by introducing a Plum-expression vector driven by a combination of the cytomegalovirus early enhancer and chicken beta-actin promoter into porcine fetal fibroblasts (PFFs). The cleavage and blastocyst formation rates of reconstructed SCNT embryos were 81.0% (34/42) and 78.6% (33/42), respectively. At 36–37 days of gestation, three fetuses systemically expressing Plum were obtained from one recipient to which 103 SCNT embryos were transferred (3/103, 2.9%). For generation of offspring expressing Plum, rejuvenated PFFs were established from one cloned fetus and used as nuclear donor cells. Four cloned offspring and one stillborn cloned offspring were produced from one recipient to which 117 SCNT embryos were transferred (5/117, 4.3%). All offspring exhibited high levels of Plum fluorescence in blood cells, such as lymphocytes, monocytes and granulocytes. In addition, the skin, heart, kidney, pancreas, liver and spleen also exhibited Plum expression. These observations demonstrated that transfer of the Plum gene did not interfere with the development of porcine SCNT embryos and resulted in the successful generation of transgenic cloned pigs that systemically expressed Plum. This is the first report of the generation and characterization of transgenic cloned pigs expressing the far-red fluorescent protein Plum.     

Degenerate slave‐makers,but nevertheless slave‐makers? Host worker relatedness in the ant Myrmoxenus kraussei

Socially parasitic ants of the formicoxenine genus Myrmoxenus exhibit considerable diversity in colony structure and life history. While some species are active slave‐makers with many workers and others are workerless ‘murder‐parasites,’ Myrmoxenus kraussei is considered as a ‘degenerate slave‐maker’ because of its very low worker numbers. Here, we document that Temnothorax recedens host workers in single colonies of M. kraussei from Lago di Garda, Italy, exhibit significantly more genetic diversity than workers in unparasitized colonies. This raises the possibility that, despite its low worker numbers, M. kraussei may actively engage in slave raids in nature.     

Japanese black cattle with orotic aciduria detected by gas-chromatography/mass-spectrometry

A 4-months-old calf of Japanese black cattle was diagnosed with orotic aciduria by gas-chromatography/mass-spectrometry (GC/MS). Until now orotic aciduria had not been reported in Japanese black cattle. The animal showed repeated diarrhea. The hematocrit was low, and microcytes and acanthocytes were observed in blood smears. The calf had lower serum total protein concentrations with a higher blood ammonia concentration. Needle-shaped crystals of orotic acid were observed in urinary sediments. Sequence homologous analysis with cattle uridine monophosphate synthase DNA indicated silent mutation in the affected calf.     

Effects of low protein intake on the development of the remaining kidney in subtotally nephrectomized immature rats: apoptosis and epidermal growth factor

Effects of low protein intake on the development of the remaining kidney in subtotally (5/6) nephrectomized immature rats were examined. Three week-old weaning rats were kept on a diet containing either 12% (Lp rats) or 18% (Np rats) protein for 4 or 8 weeks after subtotal nephrectomy. Blood urea nitrogen (BUN) concentration was determined at 2, 4, 6, and 8 weeks after 5/6 nephrectomy. At 4 or 8 weeks after the operation, glomerular sclerosis and tubulointerstitial damage were assessed by a standard semiquantitative analysis and were expressed as the glomerular sclerosis index (GSI) and interstitial fibrosis score (IFS), respectively. The localization of DNA fragmented cells in the kidney was examined by the terminal deoxynucleotidyl transferase (TdT) -mediated d-UTP-biotin nick end labeling (TUNEL) method and the localization of the epidermal growth factor (EGF) by immunohistochemical methods. BUN concentration was significantly lower in the Lp rats compared with that in the Np rats. Both 4 and 8 weeks after subtotal nephrectomy, GSI and incidence of TUNEL positive cells in the distal tubules were significantly lower in the Lp rats than in the Np rats. Four weeks after the operation, IFS was significantly lower in the Lp rats than in the Np rats. Four and 8 weeks after the operation, EGF positive cells in the distal tubules were more observed in the Lp rats than in the Np rats. These findings reveal that protein restriction is effective in preventing renal tubular scarring in immature rats and that EGF is involved in the process of this prevention.     

Variation of fruiting body productivity in protoplast fusants between compatible monokaryons ofLentinula edodes

Mycelial protoplasts of two compatible monokaryons ofLentinula edodes were prepared, and electro-fusion was undertaken. Sixteen dikaryons isolated after the electrofusion were tested for their fruiting abilities in comparison to the two dikaryons obtained by reciprocal mycelial mating. There were significant differences in fruiting body yield among the fusants, and some of them produced more fruiting bodies than did normally mated dikaryons. Although these dikaryons were divided into five genetically different groups by isozyme analyses and a cluster analysis, we could not find clear differences among the groups in terms of fruiting body yield, mycelial growth rate, or degree of wood decay. It appeared that fruiting body yield correlated positively with the mycelial growth rate but negatively with the degree of wood decay.