Seasonality and vertical structure of light-attracted insect communities in a dipterocarp forest in Sarawak

Nocturnal flying insects were collected monthly for 13 months using ultra violet light-traps set at various vertical levels in a weakly-seasonal, tropical lowland dipterocarp forest in Sarawak, Malaysia. Abundance, faunal composition, size distribution and guild structure of these samples were analyzed with respect to temperal and vertical distributions. The nocturnal flying insect community in the canopy level was highly dominated by fig wasps (84%) in individual number, and by scarabaeid beetles (28%) in weight. A principal component analysis on monthly catches detected non-random, seasonal trends of insect abundance. The first two principal trends were an alternation of wetter (September to January) and less wet seasons (February to August) and an alternation between the least wet (January to March) and the other seasons. Many insect groups were less abundant in the least wet season than the other seasons, whilst inverse patterns were found in Scarabaeidae and Tenebrionidae. Significantly positive and negative correlations between monthly catch and rainfall were detected only in ovule-feeders and in phloem-feeders, respectively. Delayed, significant negative correlations between monthly catch and 1–3 month preceding rainfall were more frequently detected in phytophages, phloem-feeders, seed-feeders, wood-borers and scavengers. The peak in abundance along vertical levels were found at the canopy level (35 m) for phloem-, ovule-, seed-, root-, fungal-feeders and nectar collectors, at an upper subcanopy level (25 m) for scavengers and aquatic predators, and at a middle subcanopy level (17 m) for ants. Catches at the emergent level (45 m) did not exceed those at the canopy level.     

Detection of the Nicotiana rustica chloroplast genome coding for the large subunit of Fraction I protein in a somatic hybrid in which only the N. tabacum chloroplast genome appeared to have been expressed

Nine plants were produced from anthers of a somatic hybrid which had been obtained by fusion of Nicotiana tabacum L. and N. rustica L. protoplants. As determined by electrofocusing, the Fraction I protein of the original somatic hybrid had largesubunit polypeptides exclusively of the N. tabacum type. Two of the plants regenerated from anthers contained Fraction-I-protein large subunits exclusively of the N. rustica type. Since each plant was regenerated from a single cell, the somatic hybrid must have had cells containing both the N. tabacum and N. rustica chloroplast genome although the latter was not expressed. Possibilities to account for this non-expression of a chloroplast genome in the somatic hybrid are discussed.     

Simultaneous determination of phenylbutazone and its metabolites in plasma and urine by high-performance liquid chromatography

A high-performance liquid chromatographic method was developed for the simultaneous determination of phenylbutazone and its metabolites, oxyphenbutazone and γ-hydroxyphenylbutazone, in plasma and urine. Samples were acidified with hydrochloric acid and extracted with benzene—cyclohexane (1:1, v/v). The extract was redissolved in methanol and chromatographed on a μBondapak C₁₅ column using a mobile phase of methanol—0.01 M sodium acetate buffer (pH 4.0) in a linear gradient (50 to 100% methanol at 5%/min; flow-rate 2.0 ml/min) in a high-performance liquid chromatograph equipped with an ultra-violet absorbance detector (254 nm). The detection limit for phenylbutazone, oxyphenbutazone and for γ-hydroxyphenylbutazone was 0.05 μg/ml.A precise and sensitive assay for the determination of phenylbutazone and its metabolites was established.     

Intermolecular Forces Involved in the Gelation and Gel Stability of Sesame 13S Globulin

The effect of various reagents on the formation and stability of heat-induced gels of sesame 13S globulins were investigated. Electrostatic interaction, the hydrophobic bond and the disulfide bond were important for forming the network structure of gels, and the hydrogen bond also had an influence on the formation of the gel. Hydrophobic bonds mainly contributed to the stability of the gel. Subunit analyses of the proteins solubilized from the gels showed the presence of a free acidic subunit (AS) and basic subunit (BS), a polymer of AS, a dimer of BS and the dimer of a fragment from AS or BS. From the results, sulfhydryl-disulfide exchange reactions during gelation are suggested.     

Changes in Casein and Egg Albumin due to Reactions with Oxidizing Methyl Linoleate in Dehydrated Systems

Casein and egg albumin were allowed to react with methyl linoleate (ML) at a relative humidity (RH) of 0% or 80% at 50°C for 10 days (protein: ML= 1:0.2 or 1:1, w/w). Changes in the molecular sizes of the reacting proteins were examined by gel filtration and gel electrophoresis. Both proteins showed similar changes, whereas the reaction at RH 80% (protein: ML= 1:1) resulted in insolubilization because of polymerization. Changes in the amino acid residues of the reacting proteins were investigated after acid (6 n HC1) and enzymatic (pepsin-pancreatin, followed by aminopeptidase-prolidase) hydrolyses. Insignificant changes were observed in the amino acid composition of proteins reacted at RH 0%. After reaction at RH 80% (protein: ML =1:1), Lys, His and Met were the only amino acids affected. The percentage loss of these amino acids after acid hydrolysis was Lys (22%), His (41%), Met (9%) for casein and Lys (22%), His (31%), Met (1%) for egg albumin. This percentage loss after enzymatic hydrolysis was Lys (41%), His (49%), Met (94%) for casein and Lys (37%), His (42%), Met (88%) for egg albumin. Some differences between our results and other researchers were also discussed.     

Purification and Characterization of Carboxypeptidases from the Sarcocarp of Watermelon

Two kinds of carboxypeptidases (F–I, F–II) were purified from the sarcocarp of watermelon (Citrullus vulgaris, var. Shimao). F–I was not purified to homogeneity. F–II was homogeneous on ultracentrifugal analysis, but a trace of impurity was detected at high concentrations by disc electrophoresis.

F–I was optimally active and stable at pH 5.0~5.5 and was strongly inhibited by DFP and HgCl₂, but not by EDTA. The molecular weight and isoelectric point were 89,000 and 4.4, respectively.

F–II was optimally active at pH 5.0 ~ 5.5 and was most stable at pH 5.5 ~ 7.0. It was completely inhibited by DFP and HgCl₂, but not by EDTA and 1, 10-phenanthroline, and it hydrolyzed an oligopeptide containing proline, glutamic acid, lysine and several neutral amino acids, sequentially from the C-terminal. The molecular weight and isolelectric point were 110,000 (5.1 S) and 5.0, respectively.

The similarity of enzymatic properties of both the present enzymes to those of other plant carboxypeptidases and pig kidney cathepsin A are discussed.     

Lipid Compositions of Photomixotrophic Green Calluses and Chlorophyll Deficient Leaves of Tobacco

Among photomixotrophic green calluses tested (N. rustica. N. tobacum L. cv. BY-4 and Samsun), the callus of Samsun had the highest contents of chlorophyll and chloroplast lipids, such as monogalactosyldiglyceride (MGDG), digalactosyldiglyceride (DGDG), sulfoquinovosyldigly-ceride (SQDG) and phosphatidylglycerol (PG). However, the chlorophyll and chloroplast lipids in the green callus of Samsun were still 1/6 and 1/3 of that in the parent leaves, respectively. The relative content of a-linolenate in MGDG, DGDG and SQDG of the green calluses were higher than that of the white calluses. The ratios of hexadecatrienoate in MGDG and hexadeceno-ate (Δ³-trans) in PG in the green calluses were trace or less compared with that of the parent leaves. The crude lipids and total fatty acid contents of the chlorophyll deficient leaves (N. taba-cum L. cv. Consolation 402 and Dominant Aurea Su/su) were almost the same as those of the normal leaves (cv. BY-4 and Samsun), although the chlorophyll contents of the chlorophyll deficient leaves were 1/3 ~ 1/4 of that of the normal leaves. The ratios of chloroplast lipids in the total polar lipids in the chlorophyll deficient leaves were a little lower than that in the normal green leaves, but the former had a slightly higher ratio of phospholipids such as phosphatidylcholine and phosphatidylethanolamine than the latter. There were few differences in the fatty acid compositions of each individual lipid betweeen both types of leaves.     

Multiscale spatial genetic structure within and between populations of wild cherry trees in nuclear genotypes and chloroplast haplotypes

Spatial genetic structure (SGS) of plants mainly depends on the effective population size and gene dispersal. Maternally inherited loci are expected to have higher genetic differentiation between populations and more intensive SGS within populations than biparentally inherited loci because of smaller effective population sizes and fewer opportunities of gene dispersal in the maternally inherited loci. We investigated biparentally inherited nuclear genotypes and maternally inherited chloroplast haplotypes of microsatellites in 17 tree populations of three wild cherry species under different conditions of tree distribution and seed dispersal. As expected, interpopulation genetic differentiation was 6–9 times higher in chloroplast haplotypes than in nuclear genotypes. This difference indicated that pollen flow 4–7 times exceeded seed flow between populations. However, no difference between nuclear and chloroplast loci was detected in within‐population SGS intensity due to their substantial variation among the populations. The SGS intensity tended to increase as trees became more aggregated, suggesting that tree aggregation biased pollen and seed dispersal distances toward shorter. The loss of effective seed dispersers, Asian black bears, did not affect the SGS intensity probably because of mitigation of the bear loss by other vertebrate dispersers and too few tree generations after the bear loss to alter SGS. The findings suggest that SGS is more variable in smaller spatial scales due to various ecological factors in local populations.     

Effects of cryopreservation methods on post-thaw motility of spermatozoa from the Japanese pearl oyster, Pinctada fucata martensii

In order to develop cryopreservation techniques for Japanese pearl oyster spermatozoa, the effects of various cryopreservation conditions on post-thaw motility were examined. Spermatozoa cryopreserved with 10% methanol (MET), dimethylformamide or dimethylacetamide plus 90% diluent comprising 80% seawater and 20% fetal bovine serum (FBS) showed higher percentages of post-thaw motility than those cryopreserved with 10% dimethylsulfoxide or glycerol. When spermatozoa were cryopreserved with various concentrations (0-20%) of MET and 100-80% diluent, 10% MET showed the highest percentages of post-thaw motility. When spermatozoa were cryopreserved with 10% MET and 90% diluent comprising various concentrations (0-100%) of FBS or Ringer solution mixed with seawater, the percentages of post-thaw motility peaked at 20% FBS or Ringer solution, and were significantly higher for 20% FBS than for 20% Ringer solution. The percentages of post-thaw motility increased with increasing dilution ratios from 2.5- to 50-fold. Spermatozoa cooled to -50 degrees C and then immersed in liquid nitrogen (LN) showed higher post-thaw motility than those cooled to -30 degrees C or -40 degrees C. When spermatozoa were cryopreserved to -50 degrees C at various cooling rates by changing the sample height above the LN surface, the post-thaw motilities of spermatozoa cooled at 10 cm (cooling rate: -21.3 degrees C/min) and 12.5 cm (-15.6 degrees C/min) from the LN surface were higher than those at 5, 7.5 or 15 cm. These results indicate that 10% MET plus 90% diluent comprising 80% seawater and 20% FBS is a suitable extender for cryopreservation of Japanese pearl oyster spermatozoa and that samples should be cooled to -50 degrees C at a cooling rate between -15 and -20 degrees C/min for efficient storage.