Preharvest Methyl Jasmonate Treatment Affects the Mineral Profile, Metabolites, and Antioxidant Capacity of Radish Microgreens Produced without Substrate

This study investigated the impact of Methyl Jasmonate (MeJA) application on the nutritional content and yield of five different colored radish microgreens. Microgreens were produced without substrate and subjected to 0.5 mM and 1.0 mM MeJA treatments on the 7th day, three days before harvest. The parameters measured included yield, dry matter, minerals, amino acids, secondary metabolites such as chlorophylls (Chls), anthocyanins, flavonoids, phenolics, glucosinolates (GSLs), vitamin C, and antioxidant capacity. MeJA at 1.0 mM generally improved yield and dry weight across cultivars, and all microgreens exhibited rich mineral and amino acid composition, with the influence of cultivar being more significant than MeJA treatment. However, MeJA enhanced all cultivars' anthocyanins, GSLs, phenolics, flavonoids, and antioxidant activities. Generally, as the antioxidant capacity is the primary factor influencing the nutritional quality of microgreens, MeJA-treated microgreens, especially with selected superior cultivars such as 'Asia purple' and 'Koregon red', could offer a potential for cultivation of value-added, eco-friendly microgreens with substrate-free cultivation.

Prediction of tannin content and quality parameters in astringent persimmons from visible and near-infrared spectroscopy

Introduction

Tannin content and postharvest quality characteristics of persimmon fruit are often determined by the destructive analysis that consumes time, does not allow the acquisition of data from the same fruit continuously, and requires expensive high-performance equipment. This research was done to investigate the potential for non-destructive estimation of astringency and quality parameters in persimmon fruit based on visible/near-infrared (VNIR) spectra.

Methods

VNIR spectra readings, the reference tannin content, and quality parameters were measured from fruits of "Cheongdo-Bansi" and "Daebong" persimmon cultivars at harvest and throughout the ripening/deastringency period. The spectra readings from half of the total fruit were utilized for the calibration set, while the other half readings were used for the prediction set. To develop models correlating the spectra data to the measured reference parameters data, the partial least square regression (PLSR) method was utilized.

Results and discussion

In the case of 'Daebong', the coefficients of determination (R2) between VNIR spectra and the actual measured values of TSS, firmness, simple sugars, and tannin content were (0.95, 0.94, 0.96, and 0.96) and (0.93, 0.89, 0.96, and 0.93), for the calibration and prediction sets, respectively. Similarly, the R2-values of (0.86, 0.93, 0.79, and 0.81) and (0.83, 0.91, 0.75, and 0.75) were recorded in 'Cheongdo-Bansi' for the calibration and prediction sets, respectively. Additionally, the acquired data were divided into two sets in a 3:1 ratio to develop predictive models and to validate the models in multiple regressions. PLSR models were developed in multiple regression to estimate the tannin content of both cultivars from firmness and simple sugars with R2-values of 0.83 and 0.79 in 'Cheongdo-Bansi' for the calibration and prediction sets, respectively, whereas, R2-values of 0.80 and 0.84 were recorded in 'Daebong' for the calibration and prediction sets, respectively. The overall findings of this study showed the possibility of using VNIR spectra for the prediction of postharvest quality and tannin contents from intact persimmon fruit with quick, chemical-free, and low-cost assessment methods. Also, the multiple regression using physicochemical parameters could fairly predict the tannin content in persimmon fruit though destructively but save time and low-cost.

Radish microgreens produced without substrate in a vertical multi-layered growing unit are rich in nutritional metabolites

Growing microgreens on trays without substrate in a vertical multilayered growing unit offers several advantages over traditional agriculture methods. This study investigated the yield performance and nutritional quality of five selections of radish microgreens grown in sprouting trays, without a substrate using only water, in an indoor multilayer cultivation system using artificial light. Various parameters were measured, including fresh weight, dry matter, chlorophyll, minerals, amino acids, phenolics, flavonoids, anthocyanins, vitamin C, glucosinolates, and antioxidant activity with four different in vitro assays. After ten days, the biomass had increased by 6-10 times, and the dry matter varied from 4.75-7.65%. The highest yield was obtained from 'Asia red', while the lowest was from 'Koregon red'. However, 'Koregon red' and 'Asia red' had the highest dry matter. 'Asia red' was found to have the highest levels of both Chls and vitamin C compared to the other cultivars, while 'Koregon red' exhibited the highest levels of total phenolics and flavonoids. Although variations in the levels of individual glucosinolates were observed, there were no significant differences in the total content of glucosinolates among the five cultivars. 'Asia purple' had the highest anthocyanin content, while 'Asia green 2' had the lowest. The K, Mg, and Na concentrations were significantly highest in 'Asia green 2', and the highest Ca was recorded in 'Asia purple'. Overall, 'Asia purple' and 'Koregon red' were the best cultivars in terms of nutritional quality among the tested radish microgreens. These cultivars exhibited high levels of dry weight, total phenolics, flavonoids, anthocyanins, essential and total amino acids, and antioxidant activities. Moreover, the implementation of this vertical cultivation method for microgreens, which relies solely on water and seeds known for their tall shoots during the sprouting could hold promise as a sustainable approach. This method can effectively be utilized for cultivar screening and fulfilling the nutritional and functional needs of the population while minimizing the environmental impacts associated with traditional agriculture practices.

Comparative Transcriptome Analysis of Softening and Ripening-Related Genes in Kiwifruit Cultivars Treated with Ethylene

This work presents the transcriptome analysis of green ‘Hayward’ (Actinidia deliciosa) and gold ‘Haegeum’ (Actinidia chinensis) kiwifruit cultivars after treatment with ethylene for three days at 25 °C. Illumina high-throughput sequencing platform was used to sequence total mRNAs and the transcriptome gene set was constructed by de novo assembly. A total of 1287 and 1724 unigenes were differentially expressed during the comparison of ethylene treatment with control in green ‘Hayward’ and gold ‘Haegeum’, respectively. From the differentially expressed unigenes, 594 and 906 were upregulated, and 693 and 818 were downregulated in the green and gold kiwifruit cultivars, respectively, when treated with ethylene. We also identified a list of genes that were expressed commonly and exclusively in the green and gold kiwifruit cultivars treated with ethylene. Several genes were expressed differentially during the ripening of kiwifruits, and their cumulative effect brought about the softening- and ripening-related changes. This work also identified and categorized genes related to softening and other changes during ripening. Furthermore, the transcript levels of 12 selected representative genes from the differentially expressed genes (DEGs) identified in the transcriptome analysis were confirmed via quantitative real-time PCR (qRT-PCR) to validate the reliability of the expression profiles obtained from RNA-Seq. The data obtained from the present study will add to the information available on the molecular mechanisms of the effects of ethylene during the ripening of kiwifruits. This study will also provide resources for further studies of the genes related to ripening, helping kiwifruit breeders and postharvest technologists to improve ripening quality.

Prestorage High CO2 and 1-MCP Treatment Reduce Chilling Injury, Prolong Storability, and Maintain Sensory Qualities and Antioxidant Activities of “Madoka” Peach Fruit

Cold storage is widely used to prolong the storability of peach fruit. However, prolonged storage at low temperatures results in chilling injury (CI) in some susceptible peach cultivars during or after cold storage. Prestorage high CO₂ and 1-methylcyclopropene (1-MCP) treatments are among the methods reported to alleviate CI and maintain the firmness of peach fruit. Hence, this study investigated CI, ripening-related physicochemical parameters, sensory qualities, total phenolics and flavonoids, and antioxidant activities of “Madoka” peach fruit to observe the effectiveness of prestorage treatment with high CO₂ and 1-MCP during the storage at 0 and 5°C. Based on the CI index, control fruits were acceptable for marketing up to 20 and 16 days of storage at 0 and 5°C, respectively, while the treated fruits could be marketable up to 28 days of storage. The results of firmness and firmness-related parameters [pectin content and polygalacturonase (PG) activity] also revealed that both high CO₂ and 1-MCP treatments were effective in delaying the ripening process of Madoka peach, and the storage at 0°C showed better results than at 5°C. However, based on the overall sensory evaluation results, the treated and control fruits were acceptable for marketing up to 20 and 12 days of storage, respectively, in both storage conditions. After deciding on fruit marketability based on the combined objective postharvest quality parameters and subjective sensory qualities, we analyzed the changes in total phenolics, flavonoids, and antioxidant activities at harvest, on the 12 and 20th days of cold storage. Storage of Madoka peach at 0°C maintained total phenolics, flavonoids, and antioxidant activities regardless of prestorage treatment with high CO₂ and 1-MCP. In summary, storing Madoka peach fruit at 0°C after treating it with 30% CO₂ for 6 h or 0.5 μl L^–1 1-MCP for 24 h reduces CI, prolongs storability, and maintains sensory quality and antioxidant properties.

Preharvest Methyl Jasmonate Treatment Increased the Antioxidant Activity and Glucosinolate Contents of Hydroponically Grown Pak Choi

Vertical hydroponics farming has emerged as an alternative solution to feed the continuously growing world population. Additionally, recent studies reported that the exogenous treatments of jasmonic acid influence the phytochemical composition of Brassicaceae. We conducted this study to determine the effect of preharvest methyl jasmonate (MeJA) treatment on the phytochemical composition and antioxidant activities of soil- and hydroponically grown pak choi. An aqueous solution of 0.5-mM MeJA was sprayed to saturation on the aerial plant part three days before harvest. The harvested pak choi was freeze-dried and then powdered to measure the antioxidant activity and the contents of chlorophylls (Chls), total phenolics and flavonoids, and glucosinolates (GSLs). The overall results revealed that pak choi grown in vertical hydroponics had higher total Chls and total phenolics than those grown in soil in the greenhouse, regardless of MeJA treatment. Nevertheless, the GSLs content and total flavonoids increased significantly due to MeJA treatment in both growing systems, and the highest values were recorded in hydroponically grown MeJA-treated pak choi. Similarly, the 2, 2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, Trolox-equivalent antioxidant capacity (ABTS), oxygen radical absorbance capacity (ORAC), and ferric-reducing antioxidant power (FRAP) were highest in hydroponically grown MeJA-treated pak choi. Taken together, the preharvest foliar treatment of MeJA can be used to improve the phytochemical composition of pak choi grown in both growing systems. Interestingly, the results strongly support the use of MeJA treatment in the vertical hydroponics growing system compared to the conventional growing system in the soil. This indicates that supplementing the vertical hydroponic growing system with preharvest MeJA treatment could be the best option to improve both the yield per square meter and the quality of pak choi. Besides, MeJA-treated pak choi could be used as a value-added horticultural commodity, as its antioxidant activity increased after treatment. Moreover, after further studies, MeJA could also be applied to other Brassica vegetables to improve their GSL contents and antioxidant properties.

The perceptions and experiences of North Korean refugee doctors concerning the burden of non-communicable diseases in North Korea

Background

Non-communicable diseases (NCDs) are a major challenge to health and social development in the 21^st century, and North Korea is no exception. However, there is a lack of information concerning NCDs in North Korea, and a different approach is needed to understand the NCDs burden there. This study examines the perceptions and experiences of refugee doctors from North Korea concerning the NCDs burden in North Korea.

Methods

Focus group discussions were conducted with 10 refugee doctors from North Korea who had been recruited through snowball sampling.

Results

North Korean refugee doctors participating in this study indicated that NCDs are the highest priority diseases, that North Koreans did not appear to have a high level of understanding and knowledge of NCDs, that economic breakdown was the primary cause of the NCDs burden, and that a high priority should be assigned to targeting NCDs in North Korea.

Discussion

Although the North Korean refugee doctors were medical professionals, they faced serious challenges accessing and managing patients with NCDs. South Korea needs to prepare for a potentially large number of people with NCDs should a freer movement of peoples occur between the two countries.

Immediate induction of heat shock proteins is not protective against cryopreservation in normal human fibroblasts

Heat shock proteins (HSPs) were first identified as proteins whose synthesis was enhanced by stresses, such as increased temperature. HSPs can protect cells from various cytotoxic factors by stabilizing proteins. Thus, it could be hypothesized that heat induced HSPs can provide protective effects against cryopreservation-induced cell death. The aim of this study was to determine whether induction of HSPs can increase the cell viability of normal human fibroblasts after cryopreservation. Cytotoxic effects of heat treatment were tested and the induction of HSPs was assessed by examining time-dependent HSP expression. A cell counting method using fluorescence microscopy was used to determine the viability of cells. In addition, the effects of geranylgeranylacetone were evaluated in terms of HSP expression and cytoskeleton changes. The results of this study showed that immediate induction of HSPs does not protect normal human fibroblasts against cryopreservation-induced cell death possibly by inducing cytoskeleton changes.

Optimization of mechanical performance of oxidative nano-particle electrode nitrile butadiene rubber conducting polymer actuator

Present work delivers a systematical evaluation of actuation efficiency of a nano-particle electrode conducting polymer actuator fabricated based on Nitrile Butadiene Rubber (NBR). Attempts are made for maximizing mechanical functionality of the nano-particle electrode conducting polymer actuator that can be driven in the air. As the conducting polymer polypyrrole of the actuator is to be fabricated through a chemical oxidation polymerization process that may impose certain limitations on both electrical and mechanical functionality of the actuator, a coordinated study for optimization process of the actuator is necessary for maximizing its performance. In this article actuation behaviors of the nano-particle electrode polypyrrole conducting polymer is studied and an optimization process for the mechanical performance maximization is performed.

High tibial osteotomy for varus gonarthrosis: a 10- to 24-year follow-up study

From January 1976 to December 1990, 66 high tibial osteotomies for medial gonarthrosis were performed in 59 patients. Thirty knees of 26 patients (18 women and 8 men) were reviewed after a mean follow-up period of 15.3 years (range, 10-24 years). The mean age of these 26 patients was 59 years at the time of operation and 75.5 years at the latest follow-up. The average femoro-tibial angle changed, from 187 degrees before surgery to 170 degrees after surgery, and to 174 degrees at the latest follow-up. Progression of osteoarthritic changes was observed in 87% for the medial and in 90% for the lateral compartment of the knee. Clinical results, assessed according to the Japanese Orthopaedic Association (JOA) knee score, showed improvement with a score of 65 points before surgery, and a score of 81 points at the latest follow-up. The overall clinical results were satisfactory for 60% of the knees. The results of this long-term follow-up study show that high tibial osteotomy for medial compartment osteoarthritis can be effective for as long as 15 years.

Modulation of skin collagen metabolism in aged and photoaged human skin in vivo

To the best of our knowledge, no study has been conducted to date to directly compare the collagen metabolism of photoaged and naturally aged human skin. In this study, we compared collagen synthesis, matrix metalloproteinase-1 levels, and gelatinase activity of sun-exposed and sun-protected skin of both young and old subjects. Using northern blot analysis, immunohistochemical stain, and Western blot analysis, we demonstrated that the levels of procollagen type I mRNA and protein in photoaged and naturally aged human skin in vivo are significantly lower than those of young skin. Furthermore, we demonstrated, by northern blot analysis, that the procollagen alpha1(I) mRNA expression of photoaged skin is much greater than that of sun-protected skin in the same individual. In situ hybridization and immunohistochemical stain were used to show that the expression of type I procollagen mRNA and protein in the fibroblasts of photoaged skin is greater than for naturally aged skin. In addition, it was found, by Western blot analysis using protein extracted from the dermal tissues, that the level of procollagen type I protein in photoaged skin is lower than that of naturally aged skin. The level of matrix metalloproteinase-1 protein and the activity of matrix metalloproteinase-2 were higher in the dermis of photoaged skin than in naturally aged skin. Our results suggest that the natural aging process decreases collagen synthesis and increases the expression of matrix metalloproteinases, whereas photoaging results in an increase of collagen synthesis and greater matrix metalloproteinase expression in human skin in vivo. Thus, the balance between collagen synthesis and degradation leading to collagen deficiency is different in photoaged and naturally aged skin.

Peroxynitrite scavenging and cytoprotective activity of 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether from the marine alga Symphyocladia latiuscula

Peroxynitrite (ONOO(-)), formed from the reaction of superoxide (O(2)*(-)) and nitric oxide (*NO), is a cytotoxic species that can oxidize several cellular components such as proteins, lipids, and DNA. It has been implicated in diseases such as Alzheimer's disease, rheumatoid arthritis, cancer, and atherosclerosis. Due to the lack of endogenous enzymes responsible for ONOO(-) inactivation, developing a specific ONOO(-) scavenger is of considerable importance. The aim of this study was to evaluate the ability of marine natural products to scavenge ONOO(-) and to protect cells against ONOO(-). Methanolic extracts of 17 marine alga were tested for their ONOO(-) scavenging activity. Among them, Symphyocladia latiuscula showed the potent scavenging activity. CH(2)CH(2) fraction was partitioned with CH(2)CH(2) following n-hexanal extraction from the methanol extract of S. latiuscula. It was highly effective for ONOO(-) scavenging activity. Further analysis of the active fractionated extract identified 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (TDB) as a potent ONOO(-) scavenger. The data demonstrated that TDB led to decreased ONOO(-)-mediated nitration of tyrosine through electron donation. TDB showed significant inhibition on nitration of bovine serum albumin and low-density lipoprotein by ONOO(-) in a dose-dependent manner. It also provided cytoprotection from cell damage induced by ONOO(-). TDB can be developed as an effective peroxynitrite scavenger for the prevention of the involved diseases.

Ultraviolet radiation increases tropoelastin mRNA expression in the epidermis of human skin in vivo

Photoaged skin contains elastotic materials in the upper reticular dermis. This phenomenon is commonly known as solar elastosis. Little is known about the mechanisms leading to the accumulation of elastotic materials in photoaged skin, however. In this study, it was demonstrated that ultraviolet irradiation induced tropoelastin mRNA expression in the keratinocytes of human skin in vivo and also in cultured human keratinocytes by in situ hybridization and reverse transcriptase polymerase chain reaction. It was also shown by northern blot analysis (n = 5) that there were increased tropoelastin mRNA levels in the forearm (sun-exposed) skin of elderly persons, compared with upper-inner arm (sun-protected) skin of the same individuals. As demonstrated by in situ hybridization compared to sun-protected skin (upper-inner arm) (n = 5), tropoelastin mRNA expression in photoaged skin was higher in keratinocytes as well as in fibroblasts. Therefore, our results suggest that keratinocytes are another source of tropoelastin production after acute and chronic ultraviolet irradiation in human skin in vivo.

Site-specific effect of testosterone on bone mineral density in male hypogonadism

To assess the correlation between the remaining serum testosterone and bone mineral density(BMD), and to determine the effect of exogenous testosterone on BMD in subjects with male hypogonadism, we evaluated the serum testosterone levels and BMDs of the femur neck, Ward's triangle and the spine(L1-4) in 20 subjects with Klinefelter's syndrome and 7 with hypogonadotropic hypogonadism before and after testosterone replacement. BMDs of the femur neck, Ward's triangle and the spine were below the age-matched normal mean at 77.8%(21/20), 74.1%(20/27) and 88.9%(24/27), respectively. There were significant differences in serum testosterone levels and the spinal BMD between the two groups and the BMD of the spine closely correlated with the serum testosterone level (R = 0.63, p < 0.001). Following a mean 11.8 +/- 4.9 months of testosterone replacement, the BMD at all sites increased significantly and the pretreatment difference in spinal BMD between the two groups disappeared. We conclude that, although testosterone may increases the bone density, it has a site-specific effect of maintaining and increasing the bone mass especially at the spine in male hypogonadism.

Paraffinoma of the penis

Augmentation of the body contour by localized injection of hard and soft paraffin rose to a zenith of popularity in the early 1900s, whereafter the severe destructive consequences of such injections became widely recognized. However in Korea, these injections are still performed much by nonmedical person. Paraffin or other mineral oil injection into body is no more a useful method to change body contour. We reviewed 26 cases of sclerosing lipogranuloma of penis with complications in recent 13 years after mean 18.5 months from previous injection of paraffin or vaseline. We conclude that the public should be informed of detrimental effects of paraffin injections and that the best treatment of penile paraffinoma is complete excision and appropriate penoplasty.

Treatment response with transurethral radiofrequency thermotherapy for symptomatic benign prostatic hyperplasia

One hundred and two patients with benign prostatic hyperplasia were treated by transurethral radio-frequency thermotherapy (TURT) device (Thermex-II, Direx, Israel) with 47.5 degrees C in single session for 2 hours and 30 minutes from November 1992 to October 1993. Among them, 83 patients, who were followed up for more than 3 months were included in this study. Twenty-seven (32.5%) patients had a history of acute retention. Pretreated values of the mean Madsen-Iversen symptom score, maximum urine flow rate, postvoiding residual urine volume, prostate volume and prostate specific antigen (PSA) were 15.4, 6.5 ml/sec, 61.3ml, 43.2ml and 0.77 ng/ml respectively. Madsen-Iversen symptom score, maximum urine flow rate were measured at 2 weeks, 1, 3 and 6 months after TURT. The residual urine volume, prostate volume and PSA level were measured at 3 and 6 months after TURT. During the follow up, the symptom score started to decrease significantly at 1 month (9.9, p < 0.01) after TURT, and gradually decreased up to 6.9 at 3 months. The maximum flow rate showed initial significant improvement at 2 weeks (8.1 ml/sec., p < 0.01), but no significant interval change was observed thereafter. The residual volume decreased significantly at 3 months (41.3 ml, p < 0.01) and no decrement was noted until 6 months. Neither the prostate volume nor PSA value changed significantly at 3 or 6 months after TURT. The improvement, which was defined as a change of 50% or more in at least one of subjective or objective symptoms showed in 63.9% (53/83) at 3 months and 57.1% (32/56) at 6 months. Both subjective and objective improvements at 3 and 6 months after treatment showed in 24.1% and 19.6%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Testosterone productivity and histostructural changes of autotransplanted rat Leydig cells

To investigate the possibility of in vivo transplantation of Leydig cells as a new biologic androgen replacement therapy, the Leydig cells procured from 6 week-old male Sprague-Dawley rats were autotransplanted, and the level of testosterone secretion and histostructural changes were observed. The renal subcapsular and intraperitoneal transplant showed higher levels of testosterone compared to subcutaneous or scrotal counterparts, and the number of transplanted cells was correlated with the level of measured testosterone. Furthermore, if the Leydig cells were transplanted intraperitoneally after the uptake on synthetic collagen, testosterone levels were higher than the ones simply transplanted without synthetic collagen uptake, resulting in 27 fold increase at 3 months. The activity of 125I-hCG decreased 20 to 40% at each month after transplantation compared to the normal levels, but no statistical significance was noted among different periods. The histologic examination revealed neovascularized capillaries and well demarcated sheet-like group of eosinophilic Leydig cells were observed at 4 weeks. But the evidence of destructive changes such as a focal inflammation with central dystropic ossification could be noted after 3 month. On electron microscopy, the marked indentation of nucleus and presence of lipochrome pigment were seen, and the number and size of smooth endoplasmic reticulum and mitochondria were reduced after 3 month. In conclusion, testosterone output could be increased to the physiologic range by increasing the number of transplant cells or utilizing collagen uptake but further effort is necessary on delaying or preventing the structural and functional decrement of Leydig cells.

Leigh's disease involving multiple organs

Leigh's disease is a rare progressive neurological disorder that is characterized light microscopically by focal spongy necrosis in the brain and electron microscopically by mitochondriopathy. We report an autopsy case of Leigh's disease that showed abnormalities in the liver, kidney and skeletal muscle as well as the central nervous system. The patient was an 18-month-old girl who has carried a diagnosis of cerebral palsy ever since her birth to a 20-year-old mother. The baby was generally hypertonic and mentally retarded. She died of severe metabolic acidosis. Postmortem examination showed growth retardation, fatty liver, fatty kidney and soft brain. Brain section showed multifocal softenings in the brainstem, basal ganglia and periventricular areas. Microscopically increased capillaries with endothelial proliferation, vacuolar degeneration and mild gliosis were seen in the brain. The axons were relatively preserved. Liver and kidneys showed microvesicular fatty change. Myofiber degeneration of the skeletal muscle was also noted. Electron microscopic examination showed markedly increased mitochondria in the parenchymal cells of the brain, liver and kidney. The mitochondria showed round to ovoid ballooned appearance including electron-dense core-like structures and pseudoinclusions of glycogen granules.

v-erbA specifically suppresses transcription of the avian erythrocyte anion transporter (band 3) gene

Previous work has established that the v-erbA oncogene inhibits the temperature-induced differentiation of chick erythroblasts transformed with temperature-sensitive oncogene mutants. Here we demonstrate that v-erbA in differentiating erythroblasts specifically arrests expression of the erythrocyte anion transporter (band 3) gene at the transcriptional level. The v-erbA-induced differentiation block can be overcome by inducing cells to differentiate at alkaline pH. Under these conditions, which possibly impair biological activity of v-erbA, the maturing cells now express the anion transporter gene at high levels. However, its transcription is specifically and rapidly suppressed if v-erbA activity is restored by culturing the cells at neutral pH. Similar but less pronounced inhibition of gene expression by v-erbA was observed for the delta-amino-levulinic acid synthase gene. Additional evidence obtained with an inhibitor of band 3 activity suggests that the v-erbA-induced inhibition of band 3 gene expression is at least partly responsible for the differentiation block caused by this oncogene.

Expression of cytoskeletal protein 4.1 during avian erythroid cellular maturation

We have isolated a cDNA clone encoding part of protein 4.1, an integral component of the erythrocyte cytoskeleton. The recombinant was isolated by immunological screening of a chicken erythroid lambda gt11 cDNA library using a monoclonal antibody directed against protein 4.1. DNA blot analysis shows that the gene is present as a single copy per haploid chicken genome, while RNA blot analysis reveals the presence of a single mRNA of 7 kilobases in reticulocytes. Message of the same size (in reduced amounts) is also present in an erythroleukemic cell line transformed by avian erythroblastosis virus and is also present in vastly reduced quantities in nonerythroid hemopoietic cells. Immunoblotting and immunofluorescence experiments show that a subset of the chicken 4.1 variant proteins is preferentially expressed during in vitro differentiation of chicken erythroleukemic cells. These data indicate that the gene is both actively transcribed and translated during early erythroid cellular maturation.