Indirect stimulation of protein synthesis by indoleacetic acid in the mung bean hypocotyl

No exact estimation of the amount of radioactive free aminoacids in the cells of the tissue with large size of apparentfree space was possible, since the exact size of the apparentfree space cannot be measured. Furthermore, estimation of thesize of the protein precursor pool, using the method of Hollemanand Key, was not possible in hypocotyl sections of mung bean(Phaseolus mungo L. cv. Black), because of the great differenceover the length of a section in the rate of the incorporationof leucine-¹⁴C into protein. Also, most of the radioactivityin the active pool disappeared within 10 min of the chase periodin the presence or absence of IAA, before the effect of IAAon protein synthesis was shown. Thus, neither can the pulse-chaseexperiment be used to study auxin-induced protein synthesis. IAA stimulated neither the formation of amino acids from acetate-¹⁴C,nor the incorporation of the newly formed amino acids into protein.However, IAA did stimulate both the uptake of sucrose-¹⁴C andpyruvate-¹⁴C into tissue and/or the formation of amino acidsfrom these substances, which resulted in stimulation of theincorporation of these radioactive amino acids into proteins.Enhancement effects of IAA on the rates of amino acid formationand the incorporation of amino acids into protein were of thesame magnitude. These results indicate that radioactive amino acids are spontaneouslyincorporated into proteins without any positive effect by IAA.Furthermore, IAA protects the degradation of some protein fractions.All diis evidence raises questions as to the validity of thehypothesis that auxin promotes protein synthesis. (Received July 17, 1972; )     

Protein synthesis rates of human PBMC and PMN can be determined simultaneously in vivo by using small blood samples

Immune cell functions can be evaluated in vivo by measuring their specific protein fractional synthesis rates (FSR). Using stable isotope dilution techniques, we describe a new method allowing simultaneous in vivo assessment of FSR in two leukocyte populations in healthy human subjects, using small blood samples. Peripheral blood mononuclear cell (PBMC) and polymorphonuclear neutrophil (PMN) FSR were measured during primed continuous intravenous infusion of L-[1-¹³C]leucine. Immune cells from 6 ml of whole blood were isolated by density gradient centrifugation. In a first study, we calculated the FSR using plasma [¹³C]leucine or -[¹³C]ketoisocaproate (KIC) enrichments as precursor pools. In a second study, we compared protein FSR in leukocytes, using enrichments of either intracellular or plasma free [¹³C]leucine as immediate precursor pools. The present approach showed a steady-state enrichment of plasma and circulating immune cell free [¹³C]leucine precursor pools. The linearity of labeled amino acid incorporation rate within mixed PBMC and PMN proteins also was verified. Postabsorptive protein FSR was 4.09 ± 0.39%/day in PBMC and 1.44 ± 0.08%/day in PMN when plasma [¹³C]KIC was the precursor pool. The difference between PBMC and PMN FSR was statistically significant, whatever the precursor pool used, suggesting large differences in their synthetic activities and functions. Use of the plasma [¹³C]KIC pool led to an underestimation of leukocyte FSR compared with the intracellular pool (PBMC: 6.04 ± 0.94%/day; PMN: 2.98 ± 0.30%/day). Hence, the intracellular free amino acid pool must be used as precursor to obtain reliable results. In conclusion, it is possible to assess immune cell metabolism in vivo in humans by using small blood samples to directly indicate their metabolic activity in various clinical situations and in response to regulating factors. peripheral blood mononuclear cells; polymorphonuclear neutrophils; protein metabolism; stable isotopes; leucine     

Dioxindole-3-Acetic Acid Conjugates Formation from Indole-3-Acetylaspartic Acid in Vicia Seedlings

When indole-3-acetic acid (IAA) is applied to the cotyledonsof broad bean seedlings (Vicia faba L. cv Chukyo), the majormetabolites found in the roots are 3-(O-ß-glucosyl)-2-indoIone-3-acetylaspartic acid (Glc-DIA-Asp) and 3-hydroxy-2-indolone-3-acetylasparticacid (DIA-Asp). In this report, the metabolic pathway from IAAto the two dioxindole-3-acetic acid (DIA) conjugates was investigatedby using [¹⁴C]IAA, [¹⁴C]DIA, [¹⁴C]indole-3-acetylaspartic acid(IAA-Asp), and [¹⁴C]IAA-[³H]Asp. The precursor of DIA-Asp wasfound to be IAA-Asp but not DIA. Incorporation of the doublelabeled IAA-Asp into the DIA conjugates demonstrated that hydrolysisof IAA-Asp was not involved in the formation of the DIA conjugates.DIA-Asp was further metabolized to Glc-DIA-Asp in the cotyledons,while formation of Glc-DIA-Asp in the roots was very low. Glc-DIA-Aspformed in the cotyledons was transported to the roots. (Received April 21, 1986; Accepted September 10, 1986)     

α 1-acid glycoprotein inhibits lipogenesis in neonatal swine adipose tissue

Serum α1-acid glycoprotein (AGP) is elevated during late gestation and at birth in the pig and rapidly declines postnatally. In contrast, the pig is born with minimal lipid stores in the adipose tissue, but rapidly accumulates lipid during the first week. The present study examined if AGP can affect adipose tissue metabolism in the neonatal pig. Isolated cell cultures or tissue explants were prepared from dorsal subcutaneous adipose tissue of preweaning piglets. Porcine AGP was used at concentrations of 0, 100, 1000 and 5000 ng/ml medium in 24 h incubations. AGP reduced the messenger RNA (mRNA) abundance of the lipogenic enzymes, malic enzyme (ME), fatty acid synthase and acetyl coA carboxylase by at least 40% (P<0.001). The activity of ME and citrate lyase were also reduced by AGP (P<0.05). Glucose oxidation was reduced by treatment with 5000 ng AGP/ml medium (P<0.05). The ¹⁴C-glucose incorporation into fatty acids was reduced by ~25% by AGP treatment for 24 h with 1000 ng AGP/ml medium (P<0.05). The decrease in glucose metabolism by AGP appears to function through an inhibition in insulin-mediated glucose oxidation and incorporation into fatty acids. This was supported by the analysis of the mRNA abundance for sterol regulatory element-binding protein (SREBP), carbohydrate regulatory element-binding protein (ChREBP) and insulin receptor substrate 1 (IRS1), which all demonstrated reductions of at least 23% in response to AGP treatment (P<0.05). These data demonstrate an overall suppression of lipogenesis due to AGP inhibition of lipogenic gene expression in vitro, which the metabolic data and SREBP, ChREBP and IRS1 gene expression analysis suggest is through an inhibition in insulin-mediated events. Second, these data suggest that AGP may contribute to limiting lipogenesis within adipose tissue during the perinatal period, as AGP levels are highest for any serum protein at birth.     

α-1 acid glycoprotein inhibits insulin responses by glucose oxidation,protein synthesis and protein breakdown in mouse C2C12 myotubes

Increased plasma α-1 acid glycoprotein (AGP) is correlated with reduced growth rates in neonatal swine. The specific physiological mechanisms contributing to this relationship are unknown. This study was performed to determine if AGP can modify muscle metabolism by examining glucose oxidation and protein synthesis in the C2C12 muscle cell line. Cells were used for experiments 4 days post-fusion as myotubes. Myotubes were exposed to AGP for 24 h, with the last 4 h used to monitor ¹⁴C-glucose oxidation or to measure protein synthesis by incorporation of ³H-tyrosine. Treatment of C2C12 myotubes with mouse AGP (100 µg/ml) reduced glucose oxidation (P<0.01, n=3 trials), whereas bovine insulin (1 µM) stimulated glucose oxidation (P<0.05, n=3 trials). Treatment with AGP in combination with insulin reduced ¹⁴C-glucose oxidation (P<0.05, n=3 trials), similar to the effect of AGP alone. Glucose transport, as measured by ³H-deoxyglucose uptake, was increased by 38% with 1 µM insulin (P<0.05, n=3 trials), whereas AGP alone increased glucose uptake by 36% (P<0.05, n=3 trials). The combination of insulin and AGP in the medium resulted in an 88% increase in glucose uptake (P<0.01, n=3 trials). Protein synthesis was measured by ³H-tyrosine incorporation into C2C12 myotubes. Insulin stimulated a 18% increase in ³H-tyrosine incorporation (P<0.05, n=6 trials). The incorporation of ³H-tyrosine into myotubes was reduced by 20% with AGP incubation (P<0.01, n=6 trials), like the 20% decrease in ³H-tyrosine incorporation in response to the combination of AGP and insulin (P<0.01, n=6 trials). Protein breakdown, as measured by the release of ³H-tyrosine from C2C12 myotubes, was reduced 27% by insulin (P<0.01, n=6 trials). Treatment with AGP had no effect on protein breakdown (P>0.05, n=6 trials), whereas incubation with both AGP and insulin reduced ³H-tyrosine release by 15% (P<0.01, n=6 trials). First, these data indicate that the acute phase protein AGP can interact with the skeletal muscle to reduce glucose oxidation, but this is not the result of an effect on glucose transport. Second, AGP can specifically reduce protein synthesis. Lastly, AGP can inhibit insulin-stimulated glucose oxidation, protein synthesis and breakdown.     

Inhibition of Auxin-Induced Ethylene Production by Lycoricidinol

Lycoricidinol, a natural growth inhibitor isolated from bulbsof Lycoris radiata Herb. strongly suppressed auxin-induced ethyleneproduction from the hypocotyl segments of etiolated mung bean(Vigna radiata Wilczek) seedlings. The inhibitor did not significantlyinhibit ethylene formation from its immediate precursor, 1-aminocyclopropane-1-carboxylicacid (ACG), during short-term (up to 4 h) incubation. The ACCcontent in tissue treated with IAA was reduced by lycoricidinolin close parallel with the inhibition of ethylene production.Examination of radioactive metabolites in tissues labeled with3,4-¹⁴C-methionine indicated that reduction of the ACC contentwas not due to any possible promotive effect of lycoricidinolon conjugation of ACC with malonate. Lycoricidinol showed noinhibitory effect on the activity of ACC synthase if appliedin vitro, but it almost completely abolished the increase inthe enzyme activity when applied in vivo during incubation ofthe tissue with IAA. Lycoricidinol also strongly inhibited incorporationof ¹⁴C-leucine into protein in the tissue. The suppression ofthe enzyme induction and, in turn, that, of ethylene productionby lycoricidinol were interpreted as being due to the inhibitionof protein synthesis. (Received September 30, 1983; Accepted December 8, 1983)     

Metabolism and Biosynthesis of Cytokinins in Tobacco Crown Gall Cells

The metabolism of ribosylzeatin (RZ) was studied using tobaccocrown gall cells which produce RZ as one of the major endogenouscytokinins. When [8-¹⁴C]RZ was fed to the cells, it was convertedinto its phosphate (which was rigorously determined to be the5'-monophosphate), RZ-O-glucoside, inosine (or its phosphate),adenosine and adenosine-O-glucoside. When [8-¹⁴C]N⁶-(²-isopentenyl)adenosine(i⁶Ado), a probable precursor of RZ, was fed to the cells, itwas converted into (i⁶Ado)-O-glucoside, inosine (or its phosphate),adenosine, adenosine-O-glucoside and adenosine phosphate, butno incorporation of radioactivity into RZ was observed. Thepresent study led to the following conclusions: i) i⁶Ado isnot a precursor of RZ in the cells, ii) both deaminase and cytokininoxidase are involved in the catabolism of cytokinin, and iii)the metabolism of RZ is quite different from that of i⁶Ado. (Received December 24, 1985; Accepted April 1, 1986)     

Wounding Inhibits Protein Synthesis yet Stimulates Polysome Formation in Aged, Excised Pea Epicotyls

Wounding of aged, previously-excised pea epicotyl segments byremoval of the basal 1–2 mm resulted in a rapid (beginningwithin 15 min) recruitment of monosomes on to polysomes andan even more rapid (maximal between 6–12 min) inhibitionof protein synthesis in the remaining tissue. This inhibitionof protein synthesis in vivo did not appear to be an artefactcaused by the removal of highly active tissue (e.g., callus,contaminating bacteria), since wounds inflicted at a site distantfrom the region analyzed still elicited the response, and proteinsynthesis in the 1–2 mm slices (normally discarded) wasinhibited even more strongly than it was in the remaining tissue.The proportion of radioactive methionine in nascent chains (boundto polysomes) increased, while the production of completed polypeptidesdecreased, after wounding. Cycloheximide, a known inhibitorof the ribosome translocation/release process mimicked someof the effects of wounding. We interpret the results to indicatethat the initial effect of wounding is to inhibit translationby inhibiting the ribosome translocation/release process, whereasthe subsequent recovery in protein synthesis is brought aboutpartly by a recovery in ribosome translocation/release and partlyby enhanced initiation. ¹ Present address: Harvard-MIT Division of Health Science andTechnology, MIT, Cambridge, Massachusetts 02139, U.S.A. ² Present address: Institute of Agricultural Environment Control,College of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama790, Japan. (Received May 26, 1986; Accepted August 4, 1986)     

Short-Term Fluctuations in the Transport of Assimilates to the Ear of Wheat Measured with Steady-State 11C-CO2-Labelling of the Flag Leaf

In order to study the regulation of photosynthate import intothe ear of wheat (Triticum aestivum L. cv. Anza), a system wasdeveloped in which the flag leaf, the major source of photosynthatefor the ear, was provided with steady-state levels of ¹¹C-CO₂for periods of several hours each time. ¹¹C is a short-livedisotope (1? c. 20?3 mm) whose breakdown products (followingpositron annihilation) include paired, high energy -rays (0?5MeV). Consequently, the movement of radioactive photosynthatethroughout the plant and into the ear could be studied in vivoduring multiple labelling sessions over the development of theear with detectors located at various positions around the plant.It was found that import into the ear was not constant in thelight during periods of rapid ear filling, even though flagleaf photosynthesis and export were constant. In more than 50%of all cases, import of ¹¹C-photosynthate into the ear tookthe form of large, regular oscillations with period lengthson the order of 70 mm. Furthermore, oscillations 180? out-of-phasewith those in the ear were observed in portions of the stembelow the point of flag leaf insertion, suggesting that regulationof oscillation may involve shifting the direction of transportbetween ear and lower plant parts. Rhythms in photosynthateimport into the ear do not appear to be synchronized to immediatefluctuations in the environment, since oscillations detectedsimultaneously in neighbouring plants were not synchronizedand had different period lengths. Key words: Triticwn aesrivum L., ¹¹CO₂, radioactive photosynthate, flag leaf, wheat ear     

Monoclonal Antibodies against Apple 1-Aminocyclopropane-l-Carboxylate Synthase

1-Aminocyclopropane-l-carboxylate (ACC) synthase from applefruits was purified over 5,000-fold by conventional column chromatography.By immunizing mice with this partially purified enzyme preparation,8 hybridoma lines producing monoclonal antibodies against appleACC synthase were isolated. While all 8 clones immunoprecipitatednative ACC synthase, only two clones recognized the putative(48 kDa) ACC synthase on Western blots. When a partially purifiedACC synthase preparation was incubated with S-adenosyl-L-[carboxyl-¹⁴C]methionine(AdoMet), only one radioactive protein of 48 kDa was detectedon sodium dodecyl sulfate-poly-acrylamide gel electrophoresis.This radioactive protein was specifically immunoprecipitatedby the monoclonal antibodies, indicating that apple ACC synthaseis specifically radiolabeled by its substrate AdoMet, as istomato ACC synthase. Thus, the monoclonal antibodies recognizedboth native and AdoMet-inactivated forms of ACC synthase. Whilethese antibodies failed to im-munoprecipitate ACC synthase isolatedfrom ripe tomato fruits, ripe avocado fruits or auxin-treatedmungbean hypocotyls, they were effective in immunoprecipitatingthe enzyme isolated from ripe pear fruits. (Received August 11, 1990; Accepted October 17, 1990)     

Biomass and production of the major dominant crustacean zooplankton in a tropical Rift Valley lake, Awasa, Ethiopia

Seasonal variation of the biomass (B), production (P) and P/Bratio of the numerically dominant crustaceans in Lake Awasa(Mesocydops aequatonalis stmilts, Thermocyclops consunilis andDiaphanosoma exisum) were studied during 1986 and 1987. Quantitativenet samples (64 (xm mesh) were taken at three stations on 10day intervals throughout 1986, and the dry weights and developmenttimes for each life stage were obtained from laboratory measurementsand cultures Total biomass of most of the dominant crustaceans,determined from 390 samples during 1986, was 44.85 mg m^–3(dry weight, DW) with adult females of Mesocyclops making >43.5%.Alona diaphana, another common crustacean, is dealt with ina separate paper, as are the Rotifera. Production of the dominantcrustaceans during 1986 was estimated by the growth incrementsummation (Winberg) and instantaneous growth (Ricker) methodsThe annual integrated production of the two dominant cyclopoidsis 535.2 mg (DW) m^–3 (Winberg) while annual crustaceanproduction totals 2.5 g (DW) m^–3 (Ricker) The mean annualP/B ratio for individual species and stages varied from 221.0for Diaphanosoma, to 121.7-143.0 for nauplii and 9.8–187 for copepodites of the cyclopoids It was 55 8 for the dominantzooplankton species Low or high zooplankton production and biomassturnover rates (P/B) cannot be used to characterize all tropicallakes consistently However, production per unit biomass is likelyto be higher in tropical lakes.     

Comparison of Photosynthetic and Photorespiratory Enzyme Activities between Green Leaves and Colorless Parts of Variegated Leaves of a C4 Plant, Stenotaphrum secundatum (Walt.) Kuntze

The activities of enzymes involved in C⁴ photosynthesis andphotorespiration in colorless parts of variegated leaves ofStenotaphrum secundatum (Walt.) Kuntze were compared with thosein green leaves. Chlorophyll content of the colorless part wasonly about 0.3–3% of that of the green leaves. The activities of chloroplastic enzymes, pyruvate, P_i dikinase,NADP⁺-malic enzyme and NADP⁺-glyceraldehyde 3-phosphate dehydrogenasewere considerably lower in colorless tissue on a fresh weightor protein basis (the ratios of the activities in the green/colorlesstissues ranging from 5 to 20). A cytoplasmic enzyme, UDP-glucosepyrophosphorylase as well as aspartate and alanine aminotransferasesshowed comparable activities in the two types of tissue, whereasPEP carboxylase in the colorless tissue had only the one-thirdactivity of that in green tissue. Differences in activitieswere also observed for the glycolate pathway enzymes (the ratiosranging from 2 to 7 for glycolate oxidase, hydroxypyruvate reductaseand serine hydroxymethyltransferase, and 7 to 15 for catalase),while cytochrome c oxidase showed comparable activity in thetwo types of tissue. The results suggest that the deficiency of thylakoid developmentin the colorless tissue influences enzyme activities not onlyin plastids but also in other cellular compartments. ¹Present address: Institute of Applied Microbiology, Universityof Tokyo, Tokyo 113, Japan. (Received March 26, 1986; Accepted June 17, 1986)     

RNA synthesis in embryo axes of germinating pea seeds

RNA synthesis during germination was investigated by labelingpea embryo axes or seedling roots with radioactive uridine oradenosine. The results indicated that all RNA species of pre-rRNAs(ribosomal precursor RNAs), rRNAs, heterodisperse-type RNA and4–5S low molecular weight RNA were synthesized from the6th to 64th hour of the period examined. At the very early stageof germination, some conspicuous labeling of the heterodisperse-typeRNA was observed after pulse-labeling. There was no great differencein the labeling patterns of various RNA species with regardto other later stages. When embryo axes were labeled for 1 hrwith ³H-adenosine from the 16th hour, about 25% of the labeledwhole cell RNA was retained on the membrane filter. The ratioof labeled poly(A)-containing RNA, however, decreased as germinationproceeded. The poly (A)-containing RNA sedimented heterodisperselywith a mean value of about 20S in a sucrose density gradient;this size-distribution did not vary throughout germination. (Received January 16, 1979; )     

大鼠海马细胞质膜的分离及其蛋白质组学分析

运用差速离心和连续蔗糖密度梯度离心的方法分离纯化成年大鼠海马组织细胞质膜并用Western blotting对质膜样品进行检测.结果表明,在蔗糖密度梯度离心介质中,膜片主要集中于蔗糖浓度为32%~42%的区段(密度约1.13~1.18),其次是20%~25% (密度约1.08~1.10)的区段.39%(密度约1.17)层面上质膜浓度和纯度最高.一维SDS-PAGE分离和CapLC-MS/MS分析后,通过数据库搜寻从大鼠海马组织细胞质膜样品中共鉴定出135种蛋白质, 其中质膜蛋白和与膜相关的蛋白质共70种(占51.9%), 主要包括Na⁺/K⁺-ATPase、Glutamate/aspartate transporter、Lipophilin、GLAST 1a等. 为研究海马组织细胞的功能和大鼠海马组织细胞质膜蛋白质数据库的建立积累了有价值的资料.     

Biosynthesis, Intracellular Transport and In Vitro Processing of 11S Globulin Precursor Proteins of Developing Castor Bean Endosperm

In vivo labeling experiments to study the biosynthesis of 11Sglobulin in developing castor bean (Ricinus communis) endospermdemonstrated that the subunit polypeptides of the 11S globulinwere synthesized as high molecular weight precursors with heterogeneousmolecular weights. These proglobulin species were not synthesizedconcomitantly during seed maturation. The largest proglobulinwas synthesized from 20 days after anthesis, whereas the smallerproglobulins were synthesized from 30 days after anthesis. Subcellularfractionation of the pulse-labeled endosperm showed that the[³⁵S]methionine label was present in proglobulins in both theendoplasmic reticulum (ER) and dense vesicles shortly afterthe pulse labeling. The label in the proglobulin in ER decreasedduring the chase and appeared in mature globulins associatedwith crystalloids of vacuoles (protein bodies). Proglobulinsin the ER fraction prepared from the pulse-labeled developingendosperm were processed in vitro into globulins by the matrixfraction of protein bodies isolated from the dry castor bean.Overall results indicate that precursor proglobulin moleculessynthesized on rough ER are transported to vacuoles via densevesicles, and are cleaved there by the matrix protease to yieldmature globulin. ¹Department of Botany, University of Maryland, Present address:CollegePark, MD 20742, U.S.A. ²Department of Biology, Faculty of Science, Kobe University,Present address:Rokkoudai, Nada, Kobe 657, Japan (Received June 1, 1987; Accepted December 16, 1987)     

脂代谢相关三基因突变小鼠肝脏差异表达蛋白组研究

应用双向电泳及质谱技术对5周龄三基因(apoE^-1- / LDLR^-1-/Lepr^db/db)联合突变小鼠和野生型小鼠肝组织的差异蛋白质进行比较研究,借此分析脂代谢相关三基因联合突变小鼠肝脏蛋白质表达特点,研究差异表达蛋白与血脂代谢紊乱和动脉粥样硬化的关系.在实验中检测到三基因联合突变小鼠和野生型小鼠肝脏中分别平均有（841±57）个和（1 017±50）个蛋白点（n=3）,两者的平均匹配率分别为71.9%,83.2%.三基因联合突变小鼠有140个蛋白点未能与野生型小鼠匹配,其中相差5倍以上的上调点和下调点分别为7个和39个.选取其中的6个点做质谱分析,鉴定为endoplasmin precursor(Grp-94)、酸性富亮氨酸核磷蛋白32家族成员A(acidic leucin-rich nuclear phosphoprotein 32 family member A)、转铁蛋白前体、果糖二磷酸酶1、纤维连接蛋白前体、补体C3前体,纤维蛋白原B β多肽7种蛋白. 该结果提示,差异表达的蛋白对三基因联合突变小鼠的血脂代谢紊乱和动脉粥样硬化发生发展过程起一定作用.     

Multiple effects of the inhibitory protein of ethylene production on cellular metabolisms

The effects of an inhibitory protein of ethylene productionisolated from etiolated mung bean hypocotyls (Planta 113: 115,1973) were investigated. Etiolated mung bean hypocotyl segmentsincubated with IAA for 3 hr (1st incubation) to induce ethylene-producingactivity were incubated for 1 hr with IAA in the presence ofthe inhibitory protein and a radioactive material to measuremetabolic activity. Under the conditions where ethylene productionwas inhibited 80% or more by the protein, RNA synthesis, proteinsynthesis and phosphate uptake were suppressed 55–60,65–80, and 60–75%, respectively. Conversion of 1-¹⁴C-acetateto CO₂, lipid, basic and neutral fractions was also inhibited,but the degrees of inhibition were much less than those forthe other processes. When the segments pretreated with the inhibitoryprotein during the 1st incubation period were washed free ofthe protein and assayed for their metabolic activities, theinhibition of RNA and protein syntheses and of phosphate uptakewas partially restored, while ethylene-producing activity wasfully restored to the control level. Similar reversible inhibitoryeffects were also observed for those metabolic activities inthe tissue segments not treated with IAA, thus not producinginduced ethylene. Oxygen uptake and conversion of U-¹⁴C-glucoseto CO₂ were not affected by the inhibitory protein. The possibilitythat the inhibitory protein acts on cell surface membranes andthe modified membranes affect the regulatory mechanism of cellularmetabolism is discussed. ¹ This investigation was supported in part by grants from theMinistries of Education (B-248009), and of Agriculture and Forestryof Japan. (Received November 4, 1977; )     

Photoinhibition of Glucose Uptake in Chlorella

In colorless mutant cells of Chlorella vulgaris (M125), endogenousrespiration in the dark was not affected by 30-min preilluminationwith white light (9,000 mW?m^–2), while exogenous respirationof glucose or fructose was inhibited significantly by the sametreatment in air, but not under N₂. This light effect on exogenousrespiration was accompanied by an inhibition of hexose uptake. When autotrophically grown wild-type cells of Chlorella vulgaris(211-11h) were incubated in glucose medium with DCMU, lightalso greatly inhibited glucose uptake and growth. Blue lightwas very effective, while red light had only a slight effect.This photoinhibitory effect was also observed in algal cellsthat had been grown in a glucose-containing medium in the dark. Using SDS-gel electrophoresis, a new protein peak with a molecularweight of 35–40 kDa was detected in plasma membrane-richcell wall fractions when Chlorella vulgaris (211-11h) cellswere transferred to a glucose-containing medium. This peak disappearedafter the algal cells were returned to the glucose-free medium.These findings suggest that this protein includes the hexose-carrierprotein. Blue light significantly inhibited the formation ofthis protein during incubation in a glucose-containing medium. ¹ Present address: Laboratory of Chemistry, Faculty of PharmaceuticalSciences, Teikyo University, Sagamiko, Kanagawa 199-01, Japan. (Received July 31, 1986; Accepted March 12, 1987)     

Traits associated with innate and adaptive immunity in pigs: heritability and associations with performance under different health status conditions

There is a need for genetic markers or biomarkers that can predict resistance towards a wide range of infectious diseases, especially within a health environment typical of commercial farms. Such markers also need to be heritable under these conditions and ideally correlate with commercial performance traits. In this study, we estimated the heritabilities of a wide range of immune traits, as potential biomarkers, and measured their relationship with performance within both specific pathogen-free (SPF) and non-SPF environments. Immune traits were measured in 674 SPF pigs and 606 non-SPF pigs, which were subsets of the populations for which we had performance measurements (average daily gain), viz. 1549 SPF pigs and 1093 non-SPF pigs. Immune traits measured included total and differential white blood cell counts, peripheral blood mononuclear leucocyte (PBML) subsets (CD4⁺ cells, total CD8α⁺ cells, classical CD8αβ⁺ cells, CD11R1⁺ cells (CD8α⁺ and CD8α^-), B cells, monocytes and CD16⁺ cells) and acute phase proteins (alpha-₁ acid glycoprotein (AGP), haptoglobin, C-reactive protein (CRP) and transthyretin). Nearly all traits tested were heritable regardless of health status, although the heritability estimate for average daily gain was lower under non-SPF conditions. There were also negative genetic correlations between performance and the following immune traits: CD11R1⁺ cells, monocytes and the acute phase protein AGP. The strength of the association between performance and AGP was not affected by health status. However, negative genetic correlations were only apparent between performance and monocytes under SPF conditions and between performance and CD11R1⁺ cells under non-SPF conditions. Although we cannot infer causality in these relationships, these results suggest a role for using some immune traits, particularly CD11R1⁺ cells or AGP concentrations, as predictors of pig performance under the lower health status conditions associated with commercial farms.     

Early germination of Arabidopsis pollen in a double null mutant for the arabinogalactan protein genes AGP6 and AGP11

The pollen specificity of the Arabidopsis arabinogalactan protein (AGP) genes AGP6 and AGP11 suggests that they are integral to pollen biogenesis, and their high percent of sequence similarity may indicate a potential for overlapping function. Arabidopsis agp6 agp11 double null mutants have been studied in our laboratory, and in the present work, we characterize the germination and growth of its pollen. When compared to wild type, mutant agp6 agp11 pollen displayed reduced germination and elongation, both in vivo and in vitro, and precocious germination inside the anthers, provided that sufficient moisture was available. This characteristic was not observed in wild type plants, even in water content conditions which for the mutant were sufficient for pollen germination. Therefore, an additional distinctive phenotypic trait of arabinogalactan proteins AGP6 and AGP11 may be to avert untimely germination of pollen. Such AGPs may control germination through water uptake, suggesting an important biological function of this gene family in pollen.