Comparative transcriptomic analysis reveals the molecular mechanism underlying seedling heterosis and its relationship with hybrid contemporary seeds DNA methylation in soybean

Heterosis is widely used in crop production, but phenotypic dominance and its underlying causes in soybeans, a significant grain and oil crop, remain a crucial yet unexplored issue. Here, the phenotypes and transcriptome profiles of three inbred lines and their resulting F1 seedlings were analyzed. The results suggest that F1 seedlings with superior heterosis in leaf size and biomass exhibited a more extensive recompilation in their transcriptional network and activated a greater number of genes compared to the parental lines. Furthermore, the transcriptional reprogramming observed in the four hybrid combinations was primarily non-additive, with dominant effects being more prevalent. Enrichment analysis of sets of differentially expressed genes, coupled with a weighted gene co-expression network analysis, has shown that the emergence of heterosis in seedlings can be attributed to genes related to circadian rhythms, photosynthesis, and starch synthesis. In addition, we combined DNA methylation data from previous immature seeds and observed similar recompilation patterns between DNA methylation and gene expression. We also found significant correlations between methylation levels of gene region and gene expression levels, as well as the discovery of 12 hub genes that shared or conflicted with their remodeling patterns. This suggests that DNA methylation in contemporary hybrid seeds have an impact on both the F1 seedling phenotype and gene expression to some extent. In conclusion, our study provides valuable insights into the molecular mechanisms of heterosis in soybean seedlings and its practical implications for selecting superior soybean varieties.

DNA hypomethylation-associated transcriptional rewiring enables resistance to heavy metal mercury (Hg) stress in rice

Mercury (Hg) is an important hazardous pollutant that can cause phytotoxicity and harm human health through the food chain. Recently, rice (Oryza sativa L.) has been confirmed as a potential Hg bioaccumulator. Although the genetic and molecular mechanisms involved in heavy metal absorption and translocation in rice have been investigated for several heavy metals, Hg is largely neglected. Here, we analyzed one Hg-resistant line in rice (RHg) derived from a DNA methyltransferase-coding gene, OsMET1-2 heterozygous mutant. Compared with its isogenic wild-type (WT), RHg exhibited a significantly higher survival rate after Hg treatment, ameliorated oxidative damage, and lower Hg uptake and translocation. RNAseq-based comparative transcriptomic analysis identified 34 potential Hg resistance-related genes involved in phytohormone signaling, abiotic stress response, and zinc (Zn) transport. Importantly, the elevated expression of Hg resistance-related genes in RHg was highly correlated with DNA hypomethylation in their putative promoter regions. An ionomic analysis unraveled a negative correlation between Zn and Hg in roots. Moreover, Hg concentration was effectively decreased by exogenous application of Zn in Hg-stressed rice plants. Our findings indicate an epigenetic basis of Hg resistance and reveal an antagonistic relationship between Hg and Zn, providing new hints towards Hg detoxification in plants. ENVIRONMENTAL IMPLICATION: Mercury (Hg) as an important hazardous pollutant adversely impacts the environment and jeopardizes human health, due to its chronicity, transferability, persistence, bioaccumulation and toxicity. In this paper, we identified 34 potential genes that may significantly contribute to Hg resistance in rice. We find the expression of Hg resistance-related genes was highly correlated with DNA hypomethylation in their putative promoter regions. Our results also revealed an antagonistic relationship between Hg and Zinc (Zn), providing new hints towards Hg detoxification in plants. Together, findings of this study extend our current understanding of Hg tolerance in rice and are informative to breed seed non-accumulating rice cultivars.

Various potentially toxic element tolerances in different rice genotypes correlate with distinct physiological responses and alterations in DNA methylation

Potentially toxic elements (PTEs) are harmful to plant growth and reduce crop productivity. In this work, we studied three rice genotypes (T-35, RZ-1, and RZ-2) to quantify the diverse PTE effects and tolerances by examining morphology, physiology, and DNA methylation patterns. Morphological results showed that T-35 exhibits the highest tolerance to all studied PTE stressors (Cu, Cd, Cr). Physiological responses under PTE stresses confirmed earlier findings, where T-35 showed a higher potassium (K⁺) content and more peroxidase (POD) accumulation in the roots than the other two rice genotypes. The differences in PTE tolerance levels observed among the three rice genotypes were also associated with variations in the heavy metal transportation (HMT) gene expression level. Moreover, methylation-sensitive blotting analysis of the selected genes showed that the DNA methylation changes occurring due to PTE treatments are mainly CHG hypomethylation in T-35 but hypermethylation in RZ-1 and RZ-2. Our results demonstrate a tight relationship among physiological response, expression levels of the HMT genes, and DNA methylation pattern under PTEs stresses. It is also indicated that plants use generic mechanisms to tolerate stresses; however, different genotypes employ different combinations of such tactics to confer tolerance, which results in diverse PTE stress tolerances. These findings shed light on the PTE stresses tolerance mechanism and help direct future breeding activities in rice.

SET DOMAIN GROUP 721 protein functions in saline-alkaline stress tolerance in the model rice variety Kitaake

To isolate the genetic locus responsible for saline-alkaline stress tolerance, we developed a high-throughput activation tagging-based T-DNA insertion mutagenesis method using the model rice (Oryza sativa L.) variety Kitaake. One of the activation-tagged insertion lines, activation tagging 7 (AC7), showed increased tolerance to saline-alkaline stress. This phenotype resulted from the overexpression of a gene that encodes a SET DOMAIN GROUP 721 protein with H3K4 methyltransferase activity. Transgenic plants overexpressing OsSDG721 showed saline-alkaline stress-tolerant phenotypes, along with increased leaf angle, advanced heading and ripening dates. By contrast, ossdg721 loss-of-function mutants showed increased sensitivity to saline-alkaline stress characterized by decreased survival rates and reduction in plant height, grain size, grain weight and leaf angle. RNA sequencing (RNA-seq) analysis of wild-type Kitaake and ossdg721 mutants indicated that OsSDG721 positively regulates the expression level of HIGH-AFFINITY POTASSIUM (K⁺ ) TRANSPORTER1;5 (OsHKT1;5), which encodes a Na⁺ -selective transporter that maintains K⁺ /Na⁺ homeostasis under salt stress. Furthermore, we showed that OsSDG721 binds to and deposits the H3K4me3 mark in the promoter and coding region of OsHKT1;5, thereby upregulating OsHKT1;5 expression under saline-alkaline stress. Overall, by generating Kitaake activation-tagging pools, we established that the H3K4 methyltransferase OsSDG721 enhances saline-alkaline stress tolerance in rice.

Genome-wide locus-specific DNA methylation repatterning may facilitate rapid evolution of mercury resistance in rice

BACKGROUND

Albeit a relatively stable epigenetic modification, DNA methylation in plants can be repatterned and play important roles in response to biotic and abiotic stresses. However, whether DNA methylation dynamics may contribute to cope with mercury (Hg) stress in plants remains to be fully investigated.

OBJECTIVE

To probe the potential roles of DNA methylation dynamics in coping with Hg stress in rice.

METHODS

Whole-genome bisulfite sequencing was used to profile the DNA methylation patterns of a rice Hg-resistant line (RHg) selected from a heterozygous mutant of the DNA methyltransferase 1 gene (OsMET1^+/-), together with its Hg-sensitive wild-type plants of cv. Nipponbare (Nip) under both normal and Hg stress conditions.

RESULTS

Genome-wide locus-specific differential methylation regions (DMRs) were detected between RHg and Nip under normal condition, the predominant DMR patterns were CG hypo-DMRs, CHG hypo-DMRs and CHH hyper-DMRs. In both lines, more hyper- than hypo-DMRs were detected at all three sequence contexts (CG, CHG and CHH) under Hg stress relative to normal condition. Comparison of DNA methylation changes in the two lines under Hg stress indicates that RHg had a more dynamic methylome than the control (Nip). Original DMRs in RHg trended to transform to opposite status (from hyper- to hypo- or vice versa) under Hg stress condition. Gene ontology analysis revealed that Hg-resistance-related DMGs were enriched in diverse biological processes.

CONCLUSIONS

Our results suggest genome-wide locus-specific DNA methylation repatterning can facilitate rapid acquisition of Hg resistance in rice.

JMJ17-WRKY40 and HY5-ABI5 modules regulate the expression of ABA-responsive genes in Arabidopsis

Abscisic acid (ABA) plays a crucial role in the adaptation of young seedlings to environmental stresses. However, the role of epigenetic components and core transcriptional machineries in the effect of ABA on seed germination and seedling growth remain unclear. Here, we show that a histone 3 lysine 4 (H3K4) demethylase, JMJ17, regulates the expression of ABA-responsive genes during seed germination and seedling growth. Using comparative interactomics, WRKY40, a central transcriptional repressor in ABA signaling, was shown to interact with JMJ17. WRKY40 facilitates the recruitment of JMJ17 to the ABI5 chromatin, which removes gene activation marks (H3K4me3) from the ABI5 chromatin, thereby repressing its expression. Additionally, WRKY40 represses the transcriptional activation activity of HY5, which can activate ABI5 expression by directly binding to its promoter. An increase in ABA concentrations decreases the affinity of WRKY40 for the ABI5 promoter. Thus, WRKY40 and JMJ17 are released from the ABI5 chromatin, activating HY5. The accumulated ABI5 protein further shows heteromeric interaction with HY5, and thus synergistically activates its own expression. Our findings reveal a novel transcriptional switch, composed of JMJ17-WRKY40 and HY5-ABI5 modules, which regulates the ABA response during seed germination and seedling development in Arabidopsis.

A randomised phase II trial of hydroxychloroquine and imatinib versus imatinib alone for patients with chronic myeloid leukaemia in major cytogenetic response with residual disease

In chronic-phase chronic myeloid leukaemia (CP-CML), residual BCR-ABL1+ leukaemia stem cells are responsible for disease persistence despite TKI. Based on in vitro data, CHOICES (CHlorOquine and Imatinib Combination to Eliminate Stem cells) was an international, randomised phase II trial designed to study the safety and efficacy of imatinib (IM) and hydroxychloroquine (HCQ) compared with IM alone in CP-CML patients in major cytogenetic remission with residual disease detectable by qPCR. Sixty-two patients were randomly assigned to either arm. Treatment 'successes' was the primary end point, defined as ≥0.5 log reduction in 12-month qPCR level from trial entry. Selected secondary study end points were 24-month treatment 'successes', molecular response and progression at 12 and 24 months, comparison of IM levels, and achievement of blood HCQ levels >2000 ng/ml. At 12 months, there was no difference in 'success' rate (p = 0.58); MMR was achieved in 80% (IM) vs 92% (IM/HCQ) (p = 0.21). At 24 months, the 'success' rate was 20.8% higher with IM/HCQ (p = 0.059). No patients progressed. Seventeen serious adverse events, including four serious adverse reactions, were reported; diarrhoea occurred more frequently with combination. IM/HCQ is tolerable in CP-CML, with modest improvement in qPCR levels at 12 and 24 months, suggesting autophagy inhibition maybe of clinical value in CP-CML.

Chromatin Remodeling Protein ZmCHB101 Regulates Nitrate-Responsive Gene Expression in Maize

Nitrate is the main source of nitrogen for plants and an essential component of fertilizers. Rapid transcriptional activation of genes encoding the high-affinity nitrate transport system (HATS) is an important strategy that plants use to cope with nitrogen deficiency. However, the specific transcriptional machineries involved in this process and the detailed transcriptional regulatory mechanism of the core HATS remain poorly understood. ZmCHB101 is the core subunit of the SWI/SNF-type ATP-dependent chromatin remodeling complex in maize. RNA-interference transgenic plants (ZmCHB101-RNAi) display abaxially curling leaves and impaired tassel and cob development. Here, we demonstrate that ZmCHB101 plays a pivotal regulatory role in nitrate-responsive gene expression. ZmCHB101-RNAi lines showed accelerated root growth and increased biomass under low nitrate conditions. An RNA sequencing analysis revealed that ZmCHB101 regulates the expression of genes involved in nitrate transport, including ZmNRT2.1 and ZmNRT2.2. The NIN-like protein (NLP) of maize, ZmNLP3.1, recognized the consensus nitrate-responsive cis-elements (NREs) in the promoter regions of ZmNRT2.1 and ZmNRT2.2, and activated the transcription of these genes in response to nitrate. Intriguingly, well-positioned nucleosomes were detected at NREs in the ZmNRT2.1 and ZmNRT2.2 gene promoters, and nucleosome densities were lower in ZmCHB101-RNAi lines than in wild-type plants, both in the absence and presence of nitrate. The ZmCHB101 protein bound to NREs and was involved in the maintenance of nucleosome occupancies at these sites, which may impact the binding of ZmNLP3.1 to NREs in the absence of nitrate. However, in the presence of nitrate, the binding affinity of ZmCHB101 for NREs decreased dramatically, leading to reduced nucleosome density at NREs and consequently increased ZmNLP3.1 binding. Our results provide novel insights into the role of chromatin remodeling proteins in the regulation of nitrate-responsive gene expression in plants.

Transgenerational memory of gene expression changes induced by heavy metal stress in rice (Oryza sativa L.)

BACKGROUND

Heavy metal toxicity has become a major threat to sustainable crop production worldwide. Thus, considerable interest has been placed on deciphering the mechanisms that allow plants to combat heavy metal stress. Strategies to deal with heavy metals are largely focused on detoxification, transport and/or sequestration. The P_1B subfamily of the Heavy Metal-transporting P-type ATPases (HMAs) was shown to play a crucial role in the uptake and translocation of heavy metals in plants. Here, we report the locus-specific expression changes in the rice HMA genes together with several low-copy cellular genes and transposable elements upon the heavy metal treatment and monitored the transgenerational inheritance of the altered expression states. We reveal that plants cope with heavy metal stress by making heritable changes in gene expression and further determined gene-specific responses to heavy metal stress.

RESULTS

We found most HMA genes were upregulated in response to heavy metal stress, and furthermore found evidence of transgenerational memory via changes in gene regulation even after the removal of heavy metals. To explore whether DNA methylation was also altered in response to the heavy metal stress, we selected a Tos17 retrotransposon for bisulfite sequencing and studied its methylation state across three generations. We found the DNA methylation state of Tos17 was altered in response to the heavy metal stress and showed transgenerational inheritance.

CONCLUSIONS

Collectively, the present study elucidates heritable changes in gene expression and DNA methylation in rice upon exposure to heavy metal stress and discusses implications of this knowledge in breeding for heavy metal tolerant crops.

Polyphenols and health: Interactions between fibre, plant polyphenols and the gut microbiota

A high‐fibre diet and one rich in fruit and vegetables have long been associated with lower risk of chronic disease. There are several possible mechanisms underpinning these associations, but one likely important factor is the production of bioactive molecules from plant‐based foods by the bacteria in the colon. This links to our growing understanding of the role of the gut microbiome in promoting health. Polyphenolic‐rich plant foods have been associated with potential health effects in many studies, but the bioavailability of polyphenol compounds, as eaten, is often very low. Most of the ingested molecules enter the large intestine where they are catabolised to smaller phenolic acids that may be the key bioactive effectors. Dietary fibres, present in plant foods, are also fermented by the bacteria to short‐chain fatty acids, compounds associated with several beneficial effects on cell turnover, metabolism and eating behaviour. Polyphenols and fibre are often eaten together, but there is a lack of research investigating the interaction between these two groups of key substrates for the colonic bacteria. In a project funded by the Biotechnology and Biological Sciences Research Council Diet and Health Research Industry Club, we are investigating whether combining different fibres and polyphenol sources can enhance the production of bioactive phenolic acids to promote health. This could lead to improved dietary recommendations and to new products with enhanced potential health‐promoting actions.

Superiorization-based multi-energy CT image reconstruction

The recently-developed superiorization approach is efficient and robust for solving various constrained optimization problems. This methodology can be applied to multi-energy CT image reconstruction with the regularization in terms of the prior rank, intensity and sparsity model (PRISM). In this paper, we propose a superiorized version of the simultaneous algebraic reconstruction technique (SART) based on the PRISM model. Then, we compare the proposed superiorized algorithm with the Split-Bregman algorithm in numerical experiments. The results show that both the Superiorized-SART and the Split-Bregman algorithms generate good results with weak noise and reduced artefacts.

Metal ion type significantly affects the morphology but not the activity of lipase–metal–phosphate nanoflowers

Using different metal ions to prepare hybrid lipase nanoflowers resulted in a variety of different morphologies, but did not significantly affect the specific activity of the enzyme.

Chlamydia psittaci exposure in pet birds

Chlamydia psittaci is a zoonotic pathogen with a wide range of avian hosts and may be transmitted to humans and cause severe disease. To assess the risk of psittacosis posed by pet birds, the seroprevalence of Chlamydia psittaci antibodies in 360 Eurasian siskins (Carduelis spinus), 289 oriental skylarks (Alauda arvensis) and 36 black-tailed grosbeaks (Coccothraustes migratorius) in Gansu province, north-western China was detected by an indirect haemagglutination assay. Twenty-seven out of 289 (9.34 %) Alauda arvensis, 45 out of 360 (12.50 %) Carduelis spinus and 2 out of 36 (5.56 %) Coccothraustes migratorius were positive for Chlamydia psittaci infection at a cut-off dilution of 1 : 16. The prevalence of Chlamydia psittaci was higher in Carduelis spinus (12.5 %) than in Alauda arvensis (9.34 %) and Coccothraustes migratorius (5.56 %); however, the differences were not statistically significant (P>0.05). Statistical analysis indicated that Chlamydia psittaci seroprevalence in adult pet birds (12.4 %, 67/540) was significantly higher than that in juvenile pet birds (4.83 %, 7/145) (P<0.01). There was no statistical difference in Chlamydia psittaci seroprevalence between male (12.4 %) and female (8.27 %) birds. To our knowledge, this is the first report indicating the seroprevalence of Chlamydia psittaci exposure in pet birds in China. Our results indicate that close contact with pet birds poses the risk of zoonotic transmission of Chlamydia psittaci.

Seroprevalence of Chlamydia psittaci infection in market-sold adult chickens, ducks and pigeons in north-western China

Chlamydia psittaci, the agent of psittacosis in humans, infects a wide range of avian species. To assess the risk of psittacosis posed by domestic birds in the urban environment, the prevalence of C. psittaci antibodies in 413 chickens (Gallus domesticus; 305 caged and 108 free-range), 334 ducks (Anas spp.; 111 caged and 223 free-range) and 312 pigeons (Columba livia) in Lanzhou, north-western China, was detected using the indirect haemagglutination assay. The specific antibodies were found in sera of 55 (13.32 %) chickens, 130 (38.92 %) ducks and 97 (31.09 %) pigeons. Statistical analysis showed that the seroprevalence of C. psittaci infection in chickens was significantly lower than that in ducks and pigeons (P<0.05). The C. psittaci seroprevalence in caged and free-range chickens was 7.54 % and 29.63 %, respectively, and the difference was statistically significant (P<0.05). The C. psittaci seroprevalence in caged and free-range ducks was 26.13 % and 45.29 %, respectively (P<0.05). To our knowledge, this is the first study indicating the presence of C. psittaci infection in market-sold chickens, ducks and pigeons in north-western China. Close contact with these birds is associated with a risk of zoonotic transmission of C. psittaci. Public education should be implemented to reduce the risk of avian to human transmission of such a pathogenic agent.

X-ray dark-field imaging modeling

Dark-field images are formed from x-ray small-angle scattering signals. The small-angle scattering signals are particularly sensitive to structural variation and density fluctuation on a length scale of several tens to hundreds of nanometers, offering a unique contrast mechanism to reveal subtle structural features of an object. In this study, based on the principle of energy conservation, we develop a physical model to describe the relationship between x-ray small-angle scattering coefficients of an object and dark-field intensity images. This model can be used to reconstruct volumetric x-ray small-angle scattering images of an object using classical tomographic algorithms. We also establish a relationship between the small-angle scattering intensity and the visibility function measured with x-ray grating imaging. The numerical simulations and phantom experiments have demonstrated the accuracy and practicability of the proposed model.

X-ray scattering tomography for biological applications

The conventional attenuation contrast imaging does not yield satisfactory sensitivity and specificity for weakly absorbing media, such as biological soft tissues. The x-ray scattering offer an important contrast mechanism to reveal structural features and density fluctuation within an object. This scattering signal carries information at the molecular and supra-molecular level, and has a tremendous implication for biomedical and other applications. In this paper, we develop a scattering imaging approach to reconstruct the electron density distribution of an object and demonstrate its feasibility in the numerical simulation.

Bioluminescence tomography based on the phase approximation model

A reconstruction method of bioluminescence sources is proposed based on a phase approximation model. Compared with the diffuse approximation, this phase approximation model more correctly predicts bioluminescence photon propagation in biological tissues, so that bioluminescence tomography can accurately locate and quantify the distribution of bioluminescence sources. The compressive sensing (CS) technique is applied to regularize the inverse source reconstruction to enhance numerical stability and efficiency. The numerical simulation and phantom experiments demonstrate the feasibility of the proposed approach.

OPTICAL PROPERTY CHARACTERIZATION BASED ON A PHASE FUNCTION APPROXIMATION MODEL

Recently, we generalized the Delta-Eddington phase function and applied it to the radiative transfer equation for modeling the photon propagation in biological tissue. The resultant phase approximation model was shown to be highly accurate with a wide range of optical properties, including the strongly absorbing and weakly scattering media. In this paper, we propose phase-approximation-based method for estimating the optical parameters. Specifically, we design an iterative algorithm to take advantage of both the global search ability of the differential evolution algorithm and the efficiency of the conjugate gradient method. Then, we demonstrate the feasibility and merits of the proposed method in both numerical simulation and phantom experiments.

Modeling photon propagation in biological tissues using a generalized Delta-Eddington phase function

Photon propagation in biological tissue is commonly described by the radiative transfer equation, while the phase function in the equation represents the scattering characteristics of the medium and has significant influence on the precision of solution and the efficiency of computation. In this work, we present a generalized Delta-Eddington phase function to simplify the radiative transfer equation to an integral equation with respect to photon fluence rate. Comparing to the popular diffusion approximation model, the solution of the integral equation is highly accurate to model photon propagation in the biological tissue over a broad range of optical parameters. This methodology is validated by Monte Carlo simulation.

Flux vector formulation for photon propagation in the biological tissue

We present a generalized delta-Eddington phase function to simplify the radiative transfer equation to an integral equation with respect to the photon flux vector. The solution of the integral equation is highly accurate to model the photon propagation in the biological tissue over a broad range of optical parameters, especially in the visible light spectrum where the diffusion approximation breaks down. The methodology is validated in the Monte Carlo simulation and can be applied in various optical imaging applications.

Regulation of CO on heterocyst differentiation and nitrate uptake in the cyanobacterium Anabaena sp. PCC 7120

AIMS

The aim of the present investigation was to study the effects of different inorganic carbon and nitrogen sources on nitrate uptake and heterocyst differentiation in the culture of cyanobacterium Anabaena sp. PCC 7120.

METHODS AND RESULTS

Anabaena was cultivated in media BG11 containing combined nitrogen and supplementary NaHCO3 or CO2. Cell growth, heterocyst differentiation, nitrate reductase (NR, EC 1.7.7.2), glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49) and NO uptake were analysed. The cells cultivated in BG11(0) medium with aeration were taken as reference. Experimental results showed that the differentiation frequency of heterocysts when the cells were cultivated with elevated CO2 was higher than that of the cells grown with air or bicarbonate. Heterocysts appeared unexpectedly when CO2 was introduced into the medium containing nitrate. However, no heterocysts emerged when CO2 was added to medium containing NH or urea, or when NaHCO3 was supplied to the medium with nitrate. Both nitrate uptake rate and nitrate reduction enzyme activity were depressed by the supplement of CO2 to the culture. The activity of G6PDH was enhanced with the increase in heterocyst differentiation frequency.

CONCLUSION

CO2 might compete with NO for energy and electrons in the uptake process and CO2 appears favoured. This led to a high intracellular C/N ratio and a relative N limitation. So the process of heterocyst differentiation was activated to supplement nitrogen uptake.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provided an attractive possibility to form more heterocysts by rapid growth of Anabaena cells cultivated in the medium containing nitrate in order to increase nitrogen fixation and hydrogen production.

[Quantitative analysis of the expression of insulin receptor and tyrosine protein kinase of patients with hepatic cirrhosis]

OBJECTIVE

To investigate the relationship between the expression of insulin receptor (IR) and the content of tyrosine protein kinase (TPK) in patients with hepatic cirrhosis.

METHODS

Glucose tolerance test (GTT), insulin, c-peptide, insulin antibodies in serum, the expression of IR and TPK were quantitively analysed in patients with hepatic cirrhosis. The amount of IR and TPK was evaluated by immunohistochemical quantitative analysis using image analyzer in 12 patients with positive HBV marks and cirrhosis. Insulin and c-peptide in serum were determined by immunoenzymemetric assay (IEMA) and insulin antibodies in serum determined by RIA.

RESULTS

IR amount in normal and abnormal GTT patients with hepatic cirrhosis was signifficantly less than that in control group (P<0.01). TPK amount in liver of patitents with abnormal GTT was less than that of normal GTT (P<0.01).

CONCLUSIONS

IR decreases in cirrhotic patients. Abnormal GTT has relation to reducing TPK activity.

Allelic loss and gain, but not genomic instability, as the major somatic mutation in primary hepatocellular carcinoma

To identify genetic abnormalities in primary hepatocellular carcinoma (HCC), we performed microsatellite analysis (MSA) on 60 Chinese HCC specimens. Utilizing a semi-quantitative MSA and 292 highly polymorphic markers spanning all 22 autosomes, we found that somatic allelic imbalance (AI) occurred frequently in HCC. To evaluate the nature of the AI, comparative genomic hybridization was performed on 20 HCC specimens. The combined use of these two methods revealed frequent allelic loss on 17p, 9p21-p23, 4q, 16q21-q23.3, 13q, 8p21-p23, and 6q24-q27, whereas there was frequent allelic gain on 1q, 17q, and 8q24. The region with the highest incidence of genomic imbalance was 17p13 (65%), followed by 9p21-p23 (55%), 4q (35-51%), 16q21-q23.3 (52%), 17p12 (49%), 13q (39-46%), 8p21-p23 (41-45%), 8q24 (41%), and 1q32 (40%). In addition, aberrations of 19p13.3, 16p13.3, 13q33-q34, 9q13-31, and 7q were reported for the first time. The presence of a close correlation of 17p13 deletion with abnormalities of some other loci implies that 17p13 could play a crucial role in oncogenesis. Interestingly, microsatellite instability was rarely seen in our patients, in contrast to that observed in European HCC samples.

[Relationship between genetic alterations and clinicopathological features in intrahepatic cholangiocarcinoma]

OBJECTIVE

To evaluate the pedigree of genetic alterations during the tumorigenesis of intrahepatic cholangiocarcinoma (ICC) and their correlation with clinicopathological features by analysis of loss of heterozygosity (LOH) in 6 tumor suppressor genes (APC, MCC, DCC, OGG1, p53 and RB1) and point mutations in Ki-ras-2 oncogene.

METHODS

Genomic DNA was isolated from paraffin-embedded slides of 22 surgically resected ICC cases by microdissection-based PCR amplification and agarose gel electrophoresis. Genetic alterations were analyzed by direct DNA sequencing.

RESULTS

The total frequency of alterations in 7 genes studied was 86.4% (19/22). Based on the pattern of altered genes and their correlation with clinicopathological parameters, the genetic alterations were classified into two groups: Group I (9/19, 47.4%): alterations in APC, MCC, DCC and Ki-ras-2,); Group II (10/19, 52.6%): alterations in p53, OGG1 and RB1. The average age of patients in Group I (mean age, 57.2 years) was significantly younger than those in Group II (mean age, 69.1 years) (P < 0.05).

CONCLUSIONS

The occurrence and development of ICC was closely related with the accumulation and cooperation of multiple genetic alterations. The genetic alterations of APC, MCC, DCC and Ki-ras-2 may play crucial roles in the early stage of development of ICC, and the genetic alterations of p53, OGG1 and RB1 may play important roles in accelerating advanced progression of ICC. The detection of the pedigree of genetic alterations in ICC may provide useful information for evaluating the state of tumor progression and clinic prognosis.

[Genotyping of multiple genetic alterations of intrahepatic cholangiocarcinoma]

OBJECTIVE

To provide genetic evidence for understanding the mechanism of oncogenesis of intrahepatic cholangiocarcinoma (ICC) by detecting the multiple genetic spectrums.

METHODS

Twenty-two cases of paraffin-embedded ICC tissue sections were microdissected and genotyped by PCR-based DNA sequencing to detect the frequencies of loss of heterozygosity (LOH) of tumor suppressor genes APC, MCC, DCC, OGG1, p53, and RB1 and of point mutation of Ki-ras-2 oncogene.

RESULTS

The genetic alteration rate was 68.8% for APC, 46.2% for DCC, 41.7% for OGG1, 37.5% for p53, 27.3% for Ki-ras-2, 22.2% for RB1, and 14.3% for MCC.

CONCLUSION

ICC-related genetic spectrum is basically composed of APC, DCC, OGG1, p53, and Ki-ras-2. Multiple genetic alteration plays an important role in the carcinogenesis of ICC.

[E-selectin and its ligand-sLeX in the metastasis of hepatocellular carcinoma]

OBJECTIVE

To study the significance of E-selectin and its ligand-sLeX in the metastasis of hepatocellular carcinoma (HCC).

METHODS

Flow cytometry and immunohistochemistry were used to detect the expression of E-selectin and its ligand-sLeX in HCC cell lines and in human HCC tissues.

RESULTS

The positive rate of E-selectin in vascular endothelial cells adjacent to cancer nest in tumors was 67.9% (19/28). In tumors accompanied with emboli or satellite foci, it was significantly higher than that without emboli or satellite foci (P < 0.05). The positive rate of E-selectin was not related to tumor size, tumor capsule, AFP, and the degree of differentiation. The positive expressions of sLeX in SMMU-7721, PLC/PRF/5 and HepGII cell lines were 7.03%, 63.35% and 97.29% respectively. The positive cells of sLeX were mainly distributed in the margin of tumors; the positive expression of sLeX in HCC cells in emboli or invasive tumor tissues was much higher than that in primary foci.

CONCLUSION

E-selectin and its ligand-sLeX are closely correlated with the metastasis of HCC.

[Simultaneous analysis of low concentrations of glucose, ethanol and glycerol by high performance liquid chromatographic method]

A method based on high performance liquid chromatography (HPLC) for the analysis of glucose, ethanol and glycerol simultaneously is presented. The baseline separation was achieved at room temperature (25-30 degrees C) on a Beckman mu-Spherogel carbohydrate column (6.5 mm i.d. x 30 cm) with H2SO4-H2O(0.5:1,000, V/V) as mobile phase at a flow rate of 1.000 mL/min. All the substances were detected with the Beckman 186 Refractive Index Detector. Under these conditions, distinct peaks of glucose, ethanol and glycerol were resolved within 15 min. The retention time in the particular condition was (6.04 +/- 0.04) min for glucose, (13.36 +/- 0.08) min for ethanol and (8.72 +/- 0.05) min for glycerol. The detection limit for glucose, ethanol and glycerol were found to be 10(-5) g, 10(-4) g and 10(-5) g respectively. A series of experiments have been performed to investigate the glucose consumption and the ethanol, glycerol production in the random growth of Saccharomyces cerevisiae with the method above. Only 0.5 mL sample was needed each time. In 30 hours after inoculation, the cell density increased from 10(6) mL-1 to 10(7) mL-1. It was found that the glucose concentration decreased approximately linearly after 8 hours, and ethanol and glycerol was detected after the delay period as expected. The results show that the method proposed is rapid and convenient with enough accuracy. The method may be used to investigate the metabolic behavior of yeast in the fermentation process at the early stage or detect the slight changes of concentrations of some objective substances in particular culture experiments.

[WAF1/CIP1 gene expression in human hepatocellular carcinoma and its relationship with p53 mutation]

OBJECTIVE

To study the WAF1 gene expression in human hepatocellular carcinoma(HCC) and its relationship with p53 mutation.

METHODS

Using semiquantitative reverse transcriptase-polymerase chain reaction(RT-PCR) and immunohistochemistry, the expression of WAF1 and p53 in 32 HCC samples and their surrounding liver tissues and 5 normal liver tissues was detected respectively.

RESULTS

The expression level of WAF1 mRNA in HCC samples was lower than that in paratumor liver tissues(1.06 U +/- 0.37 U vs 1.30 U +/- 0.37 U, P < 0.01) and its positive rate of p21WAF1 was also lower than that in paratumor liver tissues(53.1% vs 100%, P < 0.01). The expression level of WAF1 mRNA in HCC samples with intra-hepatic metastatic lesions was lower than that without intra-hepatic metastatic lesions(0.92 U +/- 0.33 U vs 1.24 U +/- 0.35 U, P < 0.01) and its positive rate of p21WAF1 was also lower than that without intra-hepatic metastatic lesions(33.3% vs 78.6%, P < 0.05). The expression level of WAF1 mRNA in HCC samples with p53 mutation was lower than that without p53 mutation (0.92 U +/- 0.28 U vs 1.16 U +/- 0.40 U, P < 0.05) and its positive rate of p21WAF1 was also lower than that without p53 mutation(15.4% vs 78.9%, P < 0.01). The percentage of cells in S-phase in p21WAF1-positive HCC samples was lower than that in p21WAF1-negative HCC samples(44.57% +/- 7.56% vs 51.83% +/- 8.51%, P < 0.01). However, no significant difference in expression of WAF1 mRNA and p21WAF1 in HCC samples was found in other clinical pathological parameters such as the degree of differentiation, the histological pattern, the size of tumors, the status of capsule in tumors and the formation of tumor thrombus of portal vein. The expression level of WAF1 mRNA in normal liver tissues was strikingly lower(0.17 U +/- 0.06 U), and the immunohistochemical staining of p21WAF1 in all normal liver tissues was positive(100%).

CONCLUSION

The expression of WAF1 gene in HCC is predominantly regulated by dependence on p53 and the reduced WAF1 expression may participate in the carcingenesis and progression of HCC and the mechanisms of infiltration and metastasis of HCC.

Primary liver tumors in China

Until now, no large series studies on the clinicopathological features of primary liver tumors (PLTs) in mainland China have been reported. The authors retrospectively investigated 3,160 cases of PLTs surgically resected at Shanghai Oriental Hospital of Hepatobiliary Surgery between January 1982 and January 1996. Most of them are true neoplasms, others are tumor-like lesions. The 3,160 cases of PLTs could be divided into 3 groups of 25 types arising from three germinal layers, of which tumor-like lesions (Group 1) were of 4 types involving 112 cases (3.5%), benign PLTs (Group 2) were of 10 types involving 499 cases (15.8%) and malignant PLTs (Group 3) were of 11 types involving 2,549 cases (80.7%). The most common type of lesion in each group was solitary necrotic nodule, cavernous hemangioma and hepatocellular carcinoma (HCC), accounting for 73.2%, 74.3% and 96.6% of their respective groups. The patients ranged in age from 5 months to 79 years (mean, 45.7 years), but the age distribution and sex ratio varied reciprocally from group to group and from lesion to lesion. For example, the mean age of the patients in Group 1 was 39.1 years of age, whereas in Group 2 and Group 3, it was 45.9 years and 49.6 years, respectively. The sex ratio of men to women was 2.6:1 in Group 1, 1:1.1 in Group 2 and 7.7:1 in Group 3. The rates of serum HBsAg positivity and concomitant liver cirrhosis in the patients with HCC were 74.4% and 72%, respectively, and the concomitant rate of cirrhosis in small HCC (<3 cm in diameter) was as high as 83.3% (P<0.05), demonstrating a close relationship of HCC with HBV infection and liver cirrhosis. HCC amounts to 78.4% of the total 3,160 PLTs in this series, indicating that HCC is the most common malignant tumor of the liver in China.

[Clinicopathological study on 3,160 cases of liver tumors]

OBJECTIVE

To study the developmental and clinicopathological characteristics of liver tumors in China.

METHODS

Routine methods were utilized to analyse the composition and clinicopathological features of 3,160 cases of liver tumors which were surgically resected during a period of 14 years.

RESULTS

25 types of liver tumors arising from three germinal layers were studied. Tumor-like lesions, 4 types, 112 cases (3.5%); benign tumors, 10 types, 499 cases (15.8%); malignant tumors, 11 types, 2,549 cases (80.7%). Of the three groups, the most common being inflammatory pseudotumors, accounting for 73.2% of tumor-like lesions, cavernous hemangioma, accounting for 74.3% of benign tumors and hepatocellular carcinoma, accounting for 96.8% of malignant tumors respectively. The association of cirrhosis in small hepatocellular carcinoma (< 3 cm) was as high as 83.2%.

CONCLUSION

A close relationship between HBV, liver cirrhosis and hepatocellular carcinoma exists.

Postoperative immunotherapy for patients with hepatocarcinoma using tumor-infiltrating lymphocytes

OBJECTIVE

To explore a more effective immunotherapy for cancer by studying tumor-infiltrating lymphocytes (TIL) of patients with hepatocarcinoma.

METHODS

TIL isolated from freshly resected tumors of 12 patients with hepatocarcinomas were activated, expanded and cultured in vitro by incubation with interleukin-2, and then infused to the patients. The TIL cytotoxicity and phenotype were determined by MTT and immunohistochemical ABC methods.

RESULTS

The average weight and number of cells of the tumor tissues for culture of TIL were 4.8 g and 5.8 x 10(7) respectively, and the median expansion time was 31.8 days in vitro. The maximal expansion achieved 1000 fold, and the mean amplification rate was 198.5 fold. Lymphokine-activated killer cell culture supernatant could stimulate TIL growth. Ten of 12 patients received immunotherapy of TIL. The number of cells infused reached 4 x 10(8)-1.1 x 10(10). In 3 cases of our series, TIL infusions were done through a drug pump with a catheter embedded in the hepatic artery. Eight patients whose primary hepatic carcinomas were resected completely were followed up for 16 months with only one case (12.5%) having recurrence. The recurrence rates of them at 6 and 12 months after tumor resection were remarkably lower than those of the patients who did not receive TIL infusion (19.4% and 41.6%, respectively). One patient whose tumor was not able to be removed received TIL infusion twice and local alcohol injection several times. He has been alive for 9 months.

CONCLUSIONS

TIL isolated from the tumors of patients with hepatocarcinoma can be activated and expanded in vitro. It demonstrated remarkably cytotoxic activity against tumor targets. TIL infusion is an effective immunotherapy for patients with hepatocarcinoma in reducing recurrence after operation.