Tissue Distribution of an Immunogenic Melanoma Associated Antigen,D-1

A human melanoma-associated antigen immunogenic in patients was recently identified by screening an expression cDNA library constructed from cultured human melanoma cell line with sera from patients with melanoma. The nucleic acid sequence of the cloned D-1 cDNA has no significant homology with previously reported mammalian genes. The cDNA D-1 encodes a peptide of about 37 kDa, which showed fivefold higher reactivity with sera from patients with melanoma than with sera from normal donors. In order to detect D-1 gene expression in vivo, in-situ hybridization and immunostaining with cRNA probe and murine anti-D-1 sera were carried out on surgically removed tissues. Digoxigenin-labeled cRNA D-1 was exclusively hybridized with mRNA in the cytoplasm of melanoma cells but not with keratinocytes and fibroblasts adjacent to melanoma nests. Polyclonal anti-D-1 antibodies were obtained by immunization of Balb/c mice with recombinant D-1 peptide and clearly reacted with melanoma cells but not with keratinocytes and fibroblasts, similar to the results of in-situ hybridization. The above information will help to assess the suitability of recombinant D-1 peptide to implement active specific immunotherapy in patients with melanoma.     

EFFECTS OF CULTURE CONDITIONS ON HYDROGENASE ACTIVITY OF SCENEDESMUS D3

The effects of culture conditions and of culture ages upon hydrogenaseactivity in Scenedesmus D₃ was investigated with nitrite andbenzoquinone as acceptors. It was noticed that level of ironin the culture medium played an important part in the developmentof hydrogenase activity. The cells grown on a medium of relatively high level of iron(10^–4 M) showed higher activity both in nitrite and benzoquinonereduction than those grown on a medium of relatively low levelof iron (10^–5 M). In the former case, hydrogenase activityappeared even after a short incubation with hydrogen (30 min). When the cells with low hydrogenase activity were transferredto a medium containing 10^–;4 M iron and the activity wasmeasured every 24 hours, the following facts were observed. (a) Nitrite reduction activity increased markedly during thefirst 24 hours and then decreased gradually during further cultivation.Furthermore, a parallelism was observed between nitrite reductionactivity and cell size. (b) On the other hand, the pattern of change in quinone reductionactivity was somewhat different from that of nitrite reduction.This activity appeared only after 3 days' cultivation, reacheda maximum at 4th or 5th day and then decreased. However, thepresence of glucose in the culture medium suppresses the appearanceof quinone reduction activity, while the nitrite reduction activitywas less markedly affected. ¹Present address: Department of Experimental Radiology, Facultyof Medicine, Kyushu University, Fukuoka.     

ROLE OF CALCIUM IN POTASSIUM UPTAKE BY PLANT ROOTS

The effects of EDTA·Mg or GEDTA·Mg on the uptakeof nutrient ions, the release of Ca⁺⁺ and nucleotides into themedium and the nucleic acid contents in rice and red bean rootswere investigated.

1. Both EDTA and EDTA·Mg induced similarly the release ofCa from roots.
2. EDTA·Mg as well as EDTA brought abouta significant repressionin K uptake, but had an insignificantor no effect on P, NH₄and NO₃ uptakes. EDTA·Ca did notrepress K, P, NH₄ andNO₃ uptakes.
3. EDTA or GEDTA acceleratedthe degradation of nucleic acid andthe release of nucleotides,while EDTA·Mg or GEDTA·Mghad no such effect.

These results indicate that the indispensable role of intracellularCa in K uptake does not appear to be directly associated withRNA metabolism. (Received July 29, 1965; )     

Respiratory Utilization of 13C-Labelled Photosynthate in Nodulated Root Systems of Soybean Plants

Kouchi, H., Akao, S. and Yoneyama, T. 1986. Respiratory utilizationof ¹³C-labelled photosynthate in nodulated root systems of soybeanplants.—J. exp. Bot. 37: 985–993. An improved method for the measurement of respiratory utilizationof current photosynthate in the nodulated root system of water-culturedsoybean (Glycine max L.) plants was developed using a steady-state¹³CO₂ labelling technique. Well-nodulated plants at the latevegetative stage were allowed to assimilate ¹³CO₂ for 10 h incontinuous light at a constant CO₂ concentration with a constant¹³C abundance. The respiratory evolution of ¹³CO₂ from rootsand nodules was measured continuously throughout the periodof ¹³CO₂ assimilation and during a subsequent 36 h chase periodby using a differential infrared ¹³CO₂ analyser. The plantswere grown with nitrogen-free or (15 mmol dm^–3)-containing culture solution for 3 d before¹³CO₂ assimilation. In plants grown without , nodule respiration averaged 69% of the total respiration of the undergroundparts over the full experimental period and the CO₂ respiredreached an apparent isotopic equilibrium at 80–85% labellingafter initiating ¹³CO₂ assimilation. By contrast, the CO₂ respiredfrom the roots did not reach an isotopic equilibrium and labellingwas only 56% at the end of exposure to ¹³CO₂ These findingsdemonstrated that nodule respiration is strongly dependent onrecently assimilated carbon compared with root respiration. Plants supplied with in the culture solution showed a decreased rate of nodule respirationand a slightly increased rate of root respiration. The extentsand time courses of labelling of respired CO₂ from both theroots and nodules were similar in the presence and absence of except that the maximum level of labelling of CO₂ derived from nodule respiration in plantswith was significantly higher (about 91%) than for plants growing without . Key words: Soybean (Glycine max L.), nodule respiration, ¹³CO₂, assimilation, carbon partitioning     

Distribution of the Germinal Vesicle Material during Progesterone-Induced Oocyte Maturation in Xenopus and in Cynops

The distribution of the germinal vesicle material in the oocyte during progesterone-induced maturation was studied in Xenopus and in Cynops. In both species, two distinctive masses of yolkfree cytoplasm appear in specific areas of the oocyte and at definite stages of maturation. One, the primary cytoplasmic mass, is formed at the basal side of the germinal vesicle during early maturation and is very RNA-rich. In Xenopus , a large part of the primary cytoplasmic mass persists as a mass during maturation and ends up as a thin disk at the boundary between the animal and the vegetal hemisphere in the mature oocyte. In Cynops , a rod-like primary cytoplasmic mass extends near to the equatorial zone and becomes indistinct in the mature oocyte. The other, the secondary cytoplasmic mass, is formed at or prior to germinal vesicle breakdown in areas around the germinal vesicle and is also RNA-rich. The secondary cytoplasmic mass is dispersed and constitutes the RNA-rich animal hemisphere cytoplasm in the mature oocyte. Observed results suggest that the primary and the secondary cytoplasmic mass contain different germinal vesicle materials.     

A revision of the genus Trixa Meigen （Diptera： Tachinidae）

The genus Trixa Meigen, 1824 is revised. Dexiotrix Villeneuve, 1936 and Trixella Mesnil, 1980, each of which was sometimes treated as a distinct genus, are treated as junior synonyms of Trixa Meigen. Two species from Sichuan and Yunnan, China, are described as new to science, viz. Trixa chinensis sp. nov. and T. chaoi sp. nov. T. alpina Meigen is treated as a junior synonym of T. caerulescens Meigen. T. nox (Shima) and T.pubiseta (Mesnil) are newly recorded from China. Males of T. pubiseta (Mesnil) and T.longipensis (Villeneuve) are described for the first time. Diagnoses, figures and a key to twelve species in Trixa are given.     

ROLE OF SULFUR IN THE CELL DIVISION OF CHLORELLA, WITH SPECIAL REFERENCE TO THE SULFUR COMPOUNDS APPEARING DURING THE PROCESS OF CELL DIVISION. I.

1. The role of sulfur in the cell division of Chlorella was studiedby following the fate of the sulfur supplied to the sulfur-deficientcells using ³⁵S as a tracer.
2. The sulfur-deficient cells whichwere unable to perform celldivision were made capable of divisionby the provision of ³⁶S-labeledsulfate under non-photosynthesizingconditions. Soon after theprovision of sulfate the labeledsulfur went rapidly into thecold perchloric acid (PCA)-solublefraction of algal cells,almost entirely in the form of sulfateand/or some other inorganicsulfur substance (s). With the lapseof time, more or less remarkablechanges occurred in the patternof ³⁵S-distribution in differentfractions of cell material.It was noticed that, at the onsetof cell division, a sulfur-containingpeptide-nucleotide compound(s)(SPN), which has been reportedearlier, appeared in a largequantity in the cold PCA-solublefraction, and that its quantitydecreased gradually during thesubsequent process of cell division,suggesting that the compoundwas transformed into some othersubstance (s), presumably withits nucleotide moiety going intonucleic acids and the peptidemoiety going into some essentialproteins.
3. Another noteworthyphenomenon observed during the process ofcell division wasthe incorporation of ³⁶S in a group of hotPCA-soluble substances.These sulfur substances were revealedto be sulfur-containingnucleotidic compounds, which might possiblybe some essentialcomponents of, or substances in close relationto, deoxypentosenucleic acid (DNA).

(Received March 1, 1960; )     

THE EFFECTS OF TEMPERATURE ON THE GERMINATION AND RADICLE GROWTH OF PHOTOSENSITIVE LETTUCE SEED

1. The time course of germination of Grand Rapids lettuce seedshas heen followed with different combinations of temperature(3°–35°) and irradiation (red or far-red light).For each set of conditions the following three parameters weredetermined: (i) the time required for half maximum germination,(ii) the rate of germination during the actively germinatingphase, and (iii) the maximum germination attained. In general,as the temperature was lowered, with dark-imbibed seeds, (i)became longer, (ii) became lower, but (iii) became progressivelyhigher. The effect of red light at any temperature was to shorten(i) and increase (ii) and (iii) over the values dark controls.Far-red light exerted an effect opposite to that of red light.Temperatures higher than 25° inhibited (ii) and (iii) underany light conditions. The optimum temperature to the actionof red and far-red light is 25°, at which the stimulatoryeffect of red light and the inhibition of this effect by far-redlight are both maximal. 2. The growth of the radicles of de-coated seeds of Grand Rapidslettuce shows two phases at all temperatures studied. PhaseI is characterized by slow but linear growth which continuesuntil shortly after visible differentiation of the radicle intothe hypocotyl and the root. Phase II is a phase of active growthin which the total length reflects mainly the length of theroot. The optimum temperature for Phase I is 25°-35°,and that, for Phase II is 25°. In neither phase, and atnone of the temperatures studied, is there any effect of redor far-red radiation on the growth of the radicle. The firstvisible sign of radicle elongation in red light induced seeds,however, takes place at exactly the same time as that of germination. 3. Similarities and dissimilarities between the germinationand the growth are pointed out, and it is concluded that thetwo phenomena are different, but proceed at sites closely associatedin the embryo. ¹Present address: Johnson Foundation for Medical Physics, Universityof Pennsylvania, Philadelphia, Pa., U.S.A.     

Maintenance and Growth of the Horny Processes of the Medaka, Oryzias latipes, in Vitro

The maintenance and growth of the horny processes of the medaka, Oryzias latipes , were investigated in vitro by organ culture of the anal-fin. Processes were induced in adult females by oral administration of ethisterone. On this day, anal-fins were removed and cultured with in media containing androgen. Early processes elongated in these media during six to eight days of culture, though they degenerated in androgen-free control media. They developed to nearly the same degree as those in intact fins in medium 199 and CMRL-1066, while they degenerated to various extents in Eagle's MEM and Dulbecco's modified EM. These results suggest that scleroblasts maintain the mass and secrete the horny substance in vitro in the presence of androgen and essential nutrients. Early processes developed on the fifth day of treatment.