Feeding activities of Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe) as affected by moisture content of wood

The relationship between the moisture content (MC) of wood blocks and the feeding activities of two Japanese subterranean termites, Coptotermes formosanus Shiraki and Reticulitermes speratus (Kolbe), was investigated with two choice tests. When three wood blocks with low MC (6%–12%), middle MC (79%–103%), and high MC (140%–182%) were exposed to workers of C. formosanus and R. speratus in a choice test, the feeding preferences were found in the middle MC blocks for C. formosanus, and the middle and high MC blocks for R. speratus, although wood blocks of low MC were also attacked. In a second choice test, wood blocks consisting of five pieces with water-impregnated (MC: 133%–191%) top, middle, or bottom piece were exposed to workers of both species. Higher consumptions were generally obtained in water-impregnated wood pieces and bottom pieces.     

Design and pilot production of a “spiral-winder” for the manufacture of cylindrical laminated veneer lumber

A new spiral-winder was developed for continuous manufacturing of cylindrical laminated veneer lumber (LVL), and a suitable resin adhesive for this cylindrical LVL manufacturing system was investigated. This phase was followed by trial manufacturing and evaluation of cylindrical LVL with the optimum resin adhesive identified. The results are summarized as follows. (1) The shortest gelation time was recorded with a mixture of two commercial resorcinol based resins (DF-1000 and D-33) at a weight ratio of 2575. (2) Bath temperature had a remarkable effect on the gelation time of the adhesive mix. (3) High bonding strength was recorded by 2575 DF-1000/D-33 adhesive mix at a high press temperature despite a short pressing duration. Based on the results of items (1) to (3), 2575 DF-1000/ D-33 is recommended for use in the new spiral-winder. (4) The mechanical properties of cylindrical LVL could be improved by using 2575 DF-1000/D-33 with wider veneer width and longer pressing time. (5) The mechanical properties, especially the modulus of rupture, of the cylindrical LVL manufactured require further improvement for practical structural application.     

Seasonal Changes in Rigor Development and Flesh Texture of Wild Japanese Sea Bass (Lateolabrax japonicus)

The season for finding the firmest sashimi made from wild Japanese sea bass was investigated. Flesh rigor tension and contraction were measured by a “new” device with isometric (muscle length kept constant) and isotonic (balance beam moves freely) transducers. Both flesh rigor tension and contraction peaks appeared at the same postmortem times, with attainment of ultimate pH and adenosine triphosphate/inosine monophosphate ratio in four seasons. Seasonal seawater temperature correlated negatively to seasonal maximum rigor contraction and positively to seasonal flesh breaking strength at 72 h postmortem. After rigor peak tension attainment, the tension relaxation was much lower than that of other wild fish species, especially in summer. The sea bass muscle resisted structure disruption in rigor isometric tension generation. Wild sea bass sashimi was firmest in breaking strength in summer.     

Incorporating accessibility limitation into the surplus production model

Limited access to aquatic populations hinders estimation of their status and establishment of effective management measures. We propose a modified surplus production model to cope with this problem. The model provides population parameters and biological reference points from a time series of annual accessible abundance data. Simulation tests showed that the model provided biological reference point estimates with little bias when sufficiently long time series were available. Even for short time series, we could obtain nearly unbiased estimates by providing information on the exploitation rate at the maximum sustainable yield (F _MSY). As an application, we fit the modified surplus production model to 7-year accessible biomass estimates of a local population of Japanese spiky sea cucumber Apostichopus japonicus using a Bayesian approach. The results indicated that the stock in the area studied was likely to have experienced recent overfishing and had a high probability of being overfished in the future.     

Water quality in drip/trickle irrigation: A review

Summary The intensive treatment of irrigation water required for the proper operation of drip irrigation systems is presently an accepted practice. To control emitter clogging, we need to know the basic causes of clogging. The major clogging factors have been identified and control measures developed to prevent emitter malfunction. All emitter clogging problems, however, have not been solved primarily because of cost. The main approach to control clogging is proper water treatment. The type of treatment is based on the quality of the irrigation water, which can be classified in terms of its physical, chemical and biological composition. The causes of emitter clogging and possible water treatment and preventive measures to maintain reliable operation are reviewed.     

Inheritance and chromosomal location of the homoeologous genes affecting phenol colour reaction of kernels in durum wheat

End-use quality of wheat for noodles is influenced by polyphenol oxidase activity and its corresponding substrates. This study investigated the chromosomal location of genes that determine phenol colour reaction of kernels in tetraploid wheat using aneuploid stocks. Polyphenol oxidase activity was estimated by the colour reaction of kernels to phenol solution. It was found that the genes located on homoeologous group 2 chromosomes have an important effect on the level of phenol colour reaction of kernels. The genes (Tc1 and Tc2) responsible for high phenol colour reaction of kernels were mapped to the long arms of chromosome 2A and chromosome 2B, respectively. The map distances were estimated to be 46.8 cM for Tc1 and 40.7 cM for Tc2 from the centromere using double-diltelosomics of durum wheat.     

Morphological analysis of viral communities in the floodwater of a Japanese paddy field

Capsid size distributions of viral communities in the floodwater of a Japanese paddy field under a long-term fertilizer trial were surveyed during the rice cultivation period by using transmission electron microscopy. The capsid size distributions were monophasic, and the median values fell within the range of 50-70 nm. The quartile intervals were narrow from either 40-50 nm or 50-60 nm to either 60-70 nm or 70-80 nm for most samples. There was no clear seasonal variation in the capsid size distribution of viral communities. The difference in size distributions among different fertilizer plots was also not found. Viral communities in the floodwater were predominated by isometric icosahedral forms. Viruses with octahedral capsids and elongated ones were rare and sporadic in the floodwater.     

Distribution of different fractions of cadmium,zinc, lead,and copper in unpolluted and polluted soils

McLaren and Crawford's method for fractionating soil Cu was modified, and used to fractionate soil Cd, Zn, Pb, and Cu in 38 soil samples from 11 soil profiles from industrially polluted and nearby unpolluted areas. Pollutant metals, especially Cd and Zn, were more soluble than the native soil metals. On average, approximately 45% of Cd was present in the CaCl₂ soluble (CA) fraction, whereas corresponding values for the other metals were below 10%. The percentages of each metal in the CA fraction followed the order Cd > Zn > Pb > Cu. The same order was observed for the acetic acid soluble (AAC) fraction. Approximately 30% of total Pb and Cu were present in the pyrophosphate soluble (PYR) fraction, and only 10% of total Cd and Zn. Approximately 20% of total Zn or Pb and 10% of Cd or Cu were present in the free oxide (OX) fraction. Only 20% of Cd and between 40–50% of the other 3 metals were present in the residual (RES) fraction. The results show that Cd is more labile than the other 3 metals.     

Background level of indium and gallium in soil with special reference to the pollution of the soils from zinc and lead smelters

The mean and range of indium content in unpolluted soils (Humic Andosols, Eutric Fluvisols, and Mollic Gleysols) was found to be 0.037 (0.016–0.078) μg/g dry wt. In soils polluted by common heavy metals, elevated values of indium up to 1.92 μg/g dry wt were observed together with an increase of cadmium, zinc, and lead. In contrast to indium, gallium content in polluted soils was nearly the same as that in unpolluted soils throughout the profiles. The mean and range of gallium content in all unpolluted and polluted samples was 14.2 (12.8–16.3) μg/g dry wt. The indium and gallium contents in 4 Canadian reference soils were also analyzed.     

Relationship between antibacterial activity of (+)-catechin derivatives and their interaction with a model membrane

(+)-Catechin derivatives with different alkyl chain lengths were synthesized from (+)-catechin and various straight chain alkylaldehydes in the presence of methyl mercaptan, and their antibacterial activities against Gram-positive bacteria were evaluated. The antibacterial activity increased markedly with elongation of the alkyl chain lengths of the derivatives and reached a maximum at a chain of four to seven carbons. Subsequently, interaction of the (+)-catechin derivatives with a model membrane using liposome was investigated. The derivatives with a chain of three carbons or more were found to have very strong affinity for the membrane. The injury action of the derivatives against the membrane was examined with liposome in which calcein was enclosed as a fluorescent indicator. The leakage was observed in the derivatives with chain lengths of four carbons or more. Particularly the derivatives with chains longer than five carbons are considered to destroy the liposome membrane judging from the degree of the fluorescent leakage. These results implied that the lipophilicity and disrupting ability of the (+)-catechin derivatives to the liposome membrane participate in their antibacterial activity.