Formation of 2-Aminobutanoic Acid from Threonine and Methionine by Mixed Rumen Ciliate Protozoa

Precursors of 2-aminobutanoic acid (2-ABA), found in the incubation medium of mixed rumen ciliate protozoa, were examined with washed or starved bacteria-free ciliates. Threonine and methionine strongly stimulated the formation of 2-ABA. Formation of 2-ABA by direct conversion of threonine and dethiomethylation of methionine was confirmed by radiotracer experiments with [U-¹⁴C]L-threonine and [carboxyl-¹⁴C] and [methyl-¹⁴C]L-methionine.     

Occurrence and density of Halobates micans (Hemiptera: Gerridae) in the eastern South Indian Ocean

Two species of ocean skaters, Halobates germanus and Halobates micans, live in the tropical and subtropical waters of the Indian Ocean. From December 1992 to December 1993, Halobates was intensively sampled in the easternmost region of the South Indian Ocean (13–18.5°S, 114–121E°), from which there have been a small number of records of Halobates. No H. germanus was caught, but a total of 1190 H. micans were collected, with densities estimated at 13 900–28 100 individuals/km². This suggests that H. micans lives in the study area at high densities comparable to those in the Atlantic and the Pacific Oceans. We also discuss the possible effects of ocean currents and winds on the geographic distributions of the two Halobates species in the eastern South Indian Ocean.     

Ecological and Evolutionary Interactions between Wild Crucifers and Their Herbivorous Insects

Abstract Insects feeding on ten species of wild crucifer were investigated. Differences in host plant range and insect community structure were examined with regard to anti-herbivore defense mechanisms. Most of the crucifer species deterred insect herbivory by disappearing in the summer or by lowering their intrinsic quality as food for insects. Species with these defense mechanisms were exploited by only a few specialized herbivorous insects that seemed to have counter defenses. The plants without these defense mechanisms were used by many herbivorous insect species. Rorippa indica lacked direct defenses, but supported a low total density of herbivore individuals. This crucifer has an indirect defense mechanism: ants attracted to floral nectar defended the plant from deleterious herbivores. Crucifers that disappeared seasonally lacked other anti-herbivore defense mechanisms. This suggests that the phonological response is an alternative other responses to herbivore attack.     

AUXIN OF TOMATO FRUIT AT DIFFERENT STAGES OF ITS DEVELOPMENT WITH A SPECIAL REFERENCE TO HIGH TEMPERATURE INJURIES

Acidic auxin in tomato fruit at various developmental stageswas examined by paper chromatography and Avena curvature test. Auxin activity of the fruit extracts was detected only in thesame R_f zone as that of authentic IAA with four solvent systems,i.e., isopropanol-ammonium hydroxide-water 10:1:1 v/v, n-butanol-ammoniumhydroxide-water 25:1:5 v/v, ethanol-water 7:3 v/v and n-butanol-aceticacid-water 4:1:1 v/v. Auxin content of fruit was the highest on the seventh day afteranthesis, when the two-celled proembryo began to grow rapidlyand the endosperm consisted of multi-cells. The second peakof auxin activity occurred on the 30th day, when the embryo,which consisted of the cotyledons, hypocotyl, and radicle, finishedits most rapid growth. No auxin activity was detected in theripe fruit. Auxin contents in fruit on the fifth, seventh, and tenth daysafter anthesis were lowered by a 4 hr high temperature treatmentat 40 given 0–3 days after anthesis. The nature of tomato auxin and its possible role in the fruitdevelopment were discussed. (Received June 30, 1966; )     

Six polymorphic microsatellite loci in the Japanese Spanish mackerel,Scomberomorus niphonius

Six polymorphic microsatellite loci were isolated for genetic structure studies of the Japanese Spanish mackerel, Scomberomorus niphonius, a severely exploited marine fish species. The number of observed alleles for each locus ranged from seven to 41, and the values of expected and observed heterozygosities were 0.546–0.946 and 0.602–1.000, respectively. These microsatellite markers should prove to be a useful tool for estimating the population genetic structure and genetic variability of Japanese Spanish mackerel.     

Isotricha jalaludinii N. Sp. Found from the Rumen of Lesser Mouse Deer, Tragulus javanicus, in Malaysia

Isotricha jalaludinii n. sp. found in the rumen of lesser mouse deer, Tragulus javanicus, in Malaysia was described and illustrated. This new species is characterized by the location and direction of the vestibulum, shape of the macronucleus, and absence of a dent at the vestibular opening. The presence of single peculiar isotrichid species in the rumen of mouse deer, which is recognized as one of the most primitive ruminants, suggests that the isotrichid ciliates similar to I. jalaludinii and Isotricha intestinalis were established at a fairly early period during the evolution of ruminants.     

Formation of Intercellular Collagen Matrix by Cultured Liver Epithelial Cells and Loss of its Ability in Hepatocarcinogenesis in vitro

Epithelial cells of normal rat liver origin (strain RL34) synthesized the α1 peptide of type I collagen. In nononcogenic cultures (RL34 and RL34EC) and a marginally oncogenic culture (RL34HII), the peptide was continuously secreted from the proliferating cells. Part of the soluble peptide was incorporated into the intercellular matrix of contact-inhibited cells after confluency, while the remainder was degraded. The intercellular matrix contained characteristic collagen fibrils which were argyrophilic and revealed a 64 nm axial periodicity. Epithelial cells of an oncogenic culture (RL34HT) secreted procollagen into the medium continuously throughout their proliferative phases and were unable to accumulate collagen fibrils in the intercellular matrix. The depletion of collagen accumulation in the hepatocarcinoma cell culture was ascribed to lack of the binding of native collagen molecules to the cell membrane and the persistence of high proteolytic activity on the cell surface.