Novel Deletion in Exon 7 of Betaine Aldehyde Dehydrogenase 2(BADH2)

The fragrance of rice is one of the premium characteristics that breeders want to include in rice varieties due to the higher market value. Nucleotide deletions in exons 2(7 bp) and 7(8 bp) of Betaine Aldehyde Dehydrogenase 2(BADH2) are associated with fragrance in rice. In this study, a new 13 bp deletion in exon 7 of the BADH2 gene was discovered in the Nang Thom Cho Dao(NTCD) variety, and the mutation has been closely related to the genetic background of indica subspecies through the Bayesian phylogenetic approach and haplotype network analysis of the 3 000 Rice Genomes Project. In addition, a set of functional markers(EX07-13F, EX07-13RN, and EX07-13RM) identified the 13 bp deletion only within NTCD(no amplified band) compared with both non-aromatic and other aromatic rice varieties(110 bp band). The deletion of 13 bases instead of 8 bases in exon 7 of BADH2 caused a premature stop codon, which down-regulated the expression of the BADH2 transcript while associated with up-regulation of OsP5CS and the high amount of 2-acetyl-1-pyrroline. It is potential to use the deletion in exon 7 of the BADH2 gene as a novel marker for adulteration and breeding of fragrant rice varieties, particularly for NTCD.

De novel heterozygous copy number deletion on 7q31.31-7q31.32 involving TSPAN12 gene with familial exudative vitreoretinopathy in a Chinese family

AIM:To investigate the genetic and clinical characteristics of patients with a large heterozygous copy number deletion on 7q31.31-7q31.32.METHODS:A family with familial exudative vitreoretinopathy(FEVR)phenotype was included in the study.Whole-exome sequencing(WES)was initially used to locate copy number variations(CNVs)on 7q31.31-31.32,but failed to detect the precise breakpoint.The long-read sequencing,Oxford Nanopore sequencing Technology(ONT)was used to get the accurate breakpoint which is verified by quantitative real-time polymerase chain reaction(QPCR)and Sanger Sequencing.RESULTS:The proband,along with her father and younger brother,were found to have a heterozygous 4.5 Mb CNV deletion located on 7q31.31-31.32,which included the FEVRrelated gene TSPAN12.The specific deletion was confirmed as del(7)(q31.31q31.32)chr7:g.119451239_123956818del.The proband exhibited a phase 2A FEVR phenotype,characterized by a falciform retinal fold,macular dragging,and peripheral neovascularization with leaking of fluorescence.These symptoms led to a significant decrease in visual acuity in both eyes.On the other hand,the affected father and younger brother showed a milder phenotype.CONCLUSION:The heterozygous CNV deletion located on 7q31.31-7q31.32 is associated with the FEVR phenotype.The use of long-read sequencing techniques is essential for accurate molecular diagnosis of genetic disorders.

Deletion and Recovery Scheme of Electronic Health Records Based onMedical Certificate Blockchain

The trusted sharing of Electronic Health Records(EHRs)can realize the efficient use of medical data resources.Generally speaking,EHRs are widely used in blockchain-based medical data platforms.EHRs are valuable private assets of patients,and the ownership belongs to patients.While recent research has shown that patients can freely and effectively delete the EHRs stored in hospitals,it does not address the challenge of record sharing when patients revisit doctors.In order to solve this problem,this paper proposes a deletion and recovery scheme of EHRs based on Medical Certificate Blockchain.This paper uses cross-chain technology to connect the Medical Certificate Blockchain and the Hospital Blockchain to real-ize the recovery of deleted EHRs.At the same time,this paper uses the Medical Certificate Blockchain and the InterPlanetary File System(IPFS)to store Personal Health Records,which are generated by patients visiting different medical institutions.In addition,this paper also combines digital watermarking technology to ensure the authenticity of the restored electronic medical records.Under the combined effect of blockchain technology and digital watermarking,our proposal will not be affected by any other rights throughout the process.System analysis and security analysis illustrate the completeness and feasibility of the scheme.

Melatonin improves synapse development by PI3K/Akt signaling in a mouse model of autism spectrum disorder

Autism spectrum disorders are a group of neurodevelopmental disorders involving more than 1100 genes,including Ctnnd2 as a candidate gene.Ctnnd2knockout mice,serving as an animal model of autis m,have been demonstrated to exhibit decreased density of dendritic spines.The role of melatonin,as a neuro hormone capable of effectively alleviating social interaction deficits and regulating the development of dendritic spines,in Ctnnd2 deletion-induced nerve injury remains unclea r.In the present study,we discove red that the deletion of exon 2 of the Ctnnd2 gene was linked to social interaction deficits,spine loss,impaired inhibitory neurons,and suppressed phosphatidylinositol-3-kinase(PI3K)/protein kinase B(Akt) signal pathway in the prefrontal cortex.Our findings demonstrated that the long-term oral administration of melatonin for 28 days effectively alleviated the aforementioned abnormalities in Ctnnd2 gene-knockout mice.Furthermore,the administration of melatonin in the prefro ntal cortex was found to improve synaptic function and activate the PI3K/Akt signal pathway in this region.The pharmacological blockade of the PI3K/Akt signal pathway with a PI3K/Akt inhibitor,wo rtmannin,and melatonin receptor antagonists,luzindole and 4-phenyl-2-propionamidotetralin,prevented the melatonin-induced enhancement of GABAergic synaptic function.These findings suggest that melatonin treatment can ameliorate GABAe rgic synaptic function by activating the PI3K/Akt signal pathway,which may contribute to the improvement of dendritic spine abnormalities in autism spectrum disorders.

Molecular Cloning and Construction of agp Gene Deletion-mutant in Cyanobacterium Synechocystis sp. PCC 6803

The agp gene encoding the ADP-glucose pyrophosphorylase involved in cyanobacterial glycogen synthesis was amplified by PCR. The resulting agp fragment was cloned in plasmid pUC118 to generate plasmid pUCA. Part of the fragment within the agp DNA was deleted and replaced by an erythromycin resistance cassette to generate plasmid pUCAE, which was used to transform the Synechocystis sp. PCC 6803 wild-type strain and a mutant with resistance to erythromycin was obtained. PCR analysis of the genomic DNA from the resulting mutant indicated that the appropriate deletion and insertion indeed had occurred. The cell growth and Chl a, glycogen content in the mutant showed difference from those in the wild-type strain. The obtained biomass as well as the Chl a content in the mutant strain was higher than that of the wild-type strain, which suggested that the photosynthesis efficiency in the agp(-) strain was higher than that in the wild-type strain. No glycogen was found in the mutant, providing evidence for the correction of the mutant in physiological level.

Hepatoprotective effects of Xiaoyao San formula on hepatic steatosis and inflammation via regulating the sex hormones metabolism

BACKGROUND The modified Xiaoyao San(MXS)formula is an adjuvant drug recommended by the National Health Commission of China for the treatment of liver cancer,which has the effect of preventing postoperative recurrence and metastasis of hepatocellular carcinoma and prolonging patient survival.However,the molecular mechanisms underlying that remain unclear.AIM To investigate the role and mechanisms of MXS in ameliorating hepatic injury,steatosis and inflammation.METHODS A choline-deficient/high-fat diet-induced rat nonalcoholic steatohepatitis(NASH)model was used to examine the effects of MXS on lipid accumulation in primary hepatocytes.Liver tissues were collected for western blotting and immunohisto chemistry(IHC)assays.Lipid accumulation and hepatic fibrosis were detected using oil red staining and Sirius red staining.The serum samples were collected for biochemical assays and NMR-based metabonomics analysis.The inflammation/lipid metabolism-related signaling and regulators in liver tissues were also detected to reveal the molecular mechanisms of MXS against NASH.RESULTS MXS showed a significant decrease in lipid accumulation and inflammatory response in hepatocytes under metabolic stress.The western blotting and IHC results indicated that MXS activated AMPK pathway but inhibited the expression of key regulators related to lipid accumulation,inflammation and hepatic fibrosis in the pathogenesis of NASH.The metabonomics analysis systemically indicated that the arachidonic acid metabolism and steroid hormone synthesis are the two main target metabolic pathways for MXS to ameliorate liver inflammation and hepatic steatosis.Mechanistically,we found that MXS protected against NASH by attenuating the sex hormone-related metabolism,especially the metabolism of male hormones.CONCLUSION MXS ameliorates inflammation and hepatic steatosis of NASH by inhibiting the metabolism of male hormones.Targeting male hormone related metabolic pathways may be the potential therapeutic approach for NASH.

A DiGeorge Syndrome Case Report—Challenges of Diagnosis and Management

Background: DiGeorge syndrome (also known as velo-cardio-facial syndrome) is a rare multisystem genetic disorder occurring in approximately 1 in 4000 to 1 in 6000 live births [1]. Although advances in genetic screening have improved diagnosis in developed countries, the condition remains underdiagnosed in developing nations such as the Republic of Moldova, where access to genetic testing and family planning services is limited. Routine prenatal screening usually includes regular ultrasounds, monitoring of blood pressure, complete blood counts, coagulation studies, glucose, urine protein, and urine culture. Current ultrasound techniques have limitations in detecting this syndrome due to variability in interpretation, and genetic testing is often performed based on clinical discretion. The ultrasound could potentially point towards a genetic problem, as in DiGeorge, if multiple cardiac malformations are spotted in utero, but most cases such as this one are diagnosed after birth while being described as totally normal on prenatal ultrasound. Purpose: This study aims to highlight the diagnostic challenges and the need for comprehensive evaluation in identifying DiGeorge syndrome, emphasizing the importance of considering the syndrome as a whole rather than focusing on isolated organ system issues. Method: We present a case report of a 6-month-old girl who, after an uneventful pregnancy and normal prenatal ultrasound, presented with cardiac insufficiency. Following extensive investigations and multiple surgical interventions, DiGeorge syndrome was diagnosed at 9 months of age. Results: The patient’s diagnosis was delayed due to the lack of prenatal markers and the reliance on separate investigations of affected organ systems. Despite several interventions aimed at managing her symptoms, the final diagnosis was made after observing the association of multiple clinical features and conducting comprehensive genetic testing. Conclusions: This case underscores the importance of a holistic approach to diagnosis, which involves a thorough patient history, integration of diverse diagnostic tests, and recognition of the syndrome’s multi-system nature. It highlights the necessity for improved diagnostic protocols and increased awareness in regions with limited access to advanced genetic testing to prevent delays in identifying DiGeorge syndrome and to facilitate timely and appropriate management.

Expression and Thermal Stability Analysis of Peat1 and the 3 Deletion Mutants

[Objective] The research aimed to reveal the functions of NAC and UBA domains in Peatl＇s thermal stability. [Method] Fusion expression vectors of Pearl protein and the 3 deletion mutants were constructed. The recombinant plasmids were induced by IPTG and the target proteins （Peatl, Peatl-△CD99,Peatl-△ND49 and Pearl-△ND108 ）were expressed obtained by AKTA and its thermal stability was analyzed. [Result] The research found that 3 deletion mutants have good thermal stability like Pearl. [Conclusion] The research demonstrated that the coexistence of NAC or UBA domains is not necessary to thermal stability of Pearl protein , and they may give the protein particular stability structure seperately.

COOH-terminal deletion of HBx gene is a frequent event in HBV-associated hepatocellular carcinoma

AIM:To investigate the hepatitis B virus (HBV) x gene (HBx) state in the tissues of HBV-related hepatocellular carcinoma (HCC) in Chinese patients and whether there were particular HBx mutations. METHODS: HBx gene was amplified and direct sequencing was used in genomic DNA samples from 20 HCC and corresponding non-cancerous liver tissues from HBsAg-positive patients. HBV DNA integration and HBx deleted mutation were validated in 45 HCC patients at different stages by Southern blot analysis and polymerase chain reaction methods. RESULTS: The frequencies of HBx point mutations were significantly lower in HCC than their corresponding non- cancerous liver tissues (11/19 vs 18/19, P = 0.019). In contrast, deletions in HBx gene were significantly higher in HCC than their non-cancerous liver tissues (16/19 vs 4/19, P < 0.001). The deletion of HBx COOH-terminal was detected in 14 HCC tissues. A specific integration of HBx at 17p13 locus was also found in 8 of 16 HCC, and all of them also exhibited full-length HBx deletions. Integrated or integrated coexistence with replicated pattern was obtained in 45.5% (20/45) - 56.8% (25/45) tumors and 40.9% (18/45) - 52.3% (23/45) non-tumor tissues. CONCLUSION: HBx deletion, especially the COOH- terminal deletion of HBx is a frequent event in HBV-associated HCC tissues in China. HBV integration had also taken place in partial HCC tissues. This supporting the hypothesis that deletion and probably integrated forms of the HBx gene may be implicated in liver carcinogenesis.

Routine screening for classical azoospermia factor deletions of the Y chromosome in azoospermic patients with Klinefelter syndrome

Aim： To evaluate the occurrence of classical azoospermia factor （AZF） deletions of the Y chromosome as a routine examination in azoospermic subjects with Klinefelter syndrome （KS）. Methods： Blood samples were collected from 95 azoospermic subjects with KS （91 subjects had a 47,XXY karyotype and four subjects had a mosaic 47,XXY/46, XY karyotype） and a control group of 93 fertile men. The values of testosterone, follicle stimulating hormone （FSH） and luteinizing hormone （LH） were measured. To determine the presence of Y chromosome microdeletions, polymerase chain reaction （PCR） of five sequence-tagged site primers （sY84, sY 129, sY 134, sY254, sY255） spanning the AZF region, was performed on isolated genomic DNA. Results： Y chromosome microdeletions were not found in any of the 95 azoosperrnic subjects with KS. In addition, using similar conditions of PCR, no microdeletions were observed in the 93 fertile men evaluated. The level of FSH in KS subjects was higher than that in fertile men （38.2 ± 10.3 mIU/mL vs. 5.4 ±2.9 mIU/mL, P 〈 0.001） and the testosterone level was lower than that in the control group （1.7 ±0.3 ng/mL vs. 4.3 ± 1.3 ng/mL, P 〈 0.001）. Conclusion： Our data and review of the published literature suggest that classical AZF deletions might not play a role in predisposing genetic background for the phenotype of azoospermic KS subjects with a 47,XXY karyotype. In addition, routine screening for the classical AZF deletions might not be required for these subjects. Further studies including partial AZFc deletions （e.g. gr/gr or b2/b3） are necessary to establish other mechanism underlying severe spermatogenesis impairment in KS.

The CRISPR/Cas9 induces large genomic fragment deletions of MSTN and phenotypic changes in sheep

The CRISPR/Cas9 system has been extensively used to engineer genetic loci for the generation of knockouts, insertions, and point mutations in animal models. However, many mutations that have been reported in animals are small insertions or deletions. This study used the CRISPR/Cas9 system to induce large DNA fragment deletions in MSTN via three guide RNAs in sheep. This successfully achieved the precise gene editing of the ovine MSTN gene by injecting both Cas9 m RNA and sg RNAs into embryos at the one-cell stage. Of 10 edited animals, 3 animals(30%) exhibited large genomic fragment deletions(~5 kb). Furthermore, the body weights of these 3 animals were significantly different(P0<0.0001, P15=0.001, P30=0.005, P60=0.027) between lambs with large deletions and wildtype lambs. In addition, the edited lambs were also significantly different(P0<0.0001, P15<0.0001, P30=0.002, P60=0.011) compared with wildtype. These results suggest that the generated MSTN knockout sheep is a reliable and effective animal model for further study. Furthermore, this method is time-and labor-saving, and efficient for the creation of animal models for agriculture, biology, and medicine.

Different pre-S deletion patterns and their association with hepatitis B virus genotypes

AIM To investigate the associations of different types of pre-S deletions with hepatitis B virus(HBV) genotypes.METHODS The sequences of the pre-S region, basal core promoter(BCP) mutation, and precore(PC) mutation were examined through direct DNA sequencing or clonal analysis and sequencing in 273 HBV carriers, namely 55 asymptomatic carriers, 55 carriers with chronic hepatitis(CH), 55 with liver cirrhosis(LC), 53 with liver cirrhotic hepatocellular carcinoma(LC-HCC), and 55 with noncirrhotic HCC. A total of 126 HBV carriers(46.2%) harbored pre-S deletions. The DNA sequences of pre-S deletion mutants from 43 age-matched genotype B(HBV/B)-infected carriers and 43 agematched genotype C(HBV/C)-infected carriers were further examined, aligned, and compared.RESULTS No significant difference was observed in the mean age distribution(P = 0.464), male sex(P = 0.805), viral load(P = 0.635), or BCP mutation(P = 0.117) between the HBV/B and HBV/C groups. However, the rate of PC mutation was significantly higher in the HBV/B-infected carriers than in the HBV/C-infected carriers(P = 0.003). Both genotypes exhibited a high rate of deletion in the C-terminal half of the pre-S1 region and N-terminus of the pre-S2 region(86.0% and 79.1% in the HBV/B group; 69.8% and 72.1% in the HBV/C group, respectively). Epitope mapping showed that deletion in several epitope sites was frequent i n both genotypes, particularly p S1-BT and p S2-B2. Conversely, the rate of p S2-B1 deletion was significantly higher in the HBV/B group(72.1% vs 37.2%, P = 0.002), and the rate of pS 2-T deletion was significantly higher in the HBV/C group(48.8% vs 25.6%, P = 0.044). Functional mapping showed that the rate of deletion in three functional sites(the nucleocapsid binding site, start codon of M, and site for viral secretion) located in the N-terminus of the pre-S2 region was significantly higher in the HBV/B group(P < 0.05). One type of N-terminus pre-S1 deletion mutant with deletion of the start codon of the L protein was frequently observed in the HBV/C group(20.9% vs 9.3%, P = 0.228), particularly in the LC patients(42.9% vs 12.5%). Different patterns of pre-S deletions were also found between the HBV/B and HBV/C groups according to different clinical outcomes. In CH patients, deletion in the site for polymerized human serum albumin was more frequent in the HBV/B group(88.9% vs 36.4%, P = 0.028). In the LC-HCC patients, the rate of deletion in the pre-S2 region was significantly higher in the HBV/B group than in the HBV/C group(P < 0.05).CONCLUSION HBV/B- and HBV/C-infected carriers exhibit different patterns of pre-S deletion, which may be associated with the progression of liver diseases.

Clinical and pathological correlation of the microdeletion of Y chromosome for the 30 patients with azoospermia and severe oligoasthenospermia

Aim: To review the accumulated 30 patients with different area of Y chromosome microdeletions, focusing on their correlation with the clinical and pathological findings. Methods: A total of 334 consecutive infertile men with azoospermia (218 patients) and severe oligoasthenospermia (116 patients) were screened. Complete physical and endocrinological examinations, general chromosome study and multiplex polymerase chain reaction assay to evaluate the Y chromosome microdeletion were performed. Ten patients received testicular biopsy. Then the clinical and pathological findings were analyzed with reference to the areas of Y chromosome microdeletion. Results: There is a decline of the percentage of sperm appearing in semen in the group that the gene deletion region from AZFc to AZFb. The clinical evidence of the impairment (decreased testicular size and elevated serum FSH) is also relevantly aggravated in this group. However, the pathology of testicular biopsy specimen was poorly correlated with the different deletion areas of the Y chromosome, which may be due to the limited number of specimens. Conclusion: The clinical correlation of spermatogenic impairment to the different AZF deletion regions may provide the information for the infertile couples in pre-treatment counseling.

PCR analysis of Yq microdeletions in infertile males, a study from South India

AIM: To estimate the frequency of microdeletions in the long arm of Y-chromosome of 20 infertile males from South India. METHODS: Polymerase chain reaction (PCR) amplification using Y-specific STS of azoospermia factor (AZF) regions i.e., SY 84 for AZFa, SY 127 for AZFb and SY 254 for AZFc. RESULTS: Of the 20 infertile subjects 3 (15 %), one azoospermic and two oligozoospermic, showed microdeletions in the AZF region of Y-chromosome. CONCLUSION: The frequency of deletions involving AZF region of the Y-chromosome is 15 % in azoospermic and severely oligozoospermic infertile men. PCR amplification of AZF locus is useful for the diagnosis of microdeletions in the Y-chromosome.

A Data Assured Deletion Scheme in Cloud Storage

In order to provide a practicable solution to data confidentiality in cloud storage service,a data assured deletion scheme,which achieves the fine grained access control,hopping and sniffing attacks resistance,data dynamics and deduplication,is proposed.In our scheme,data blocks are encrypted by a two-level encryption approach,in which the control keys are generated from a key derivation tree,encrypted by an All-OrNothing algorithm and then distributed into DHT network after being partitioned by secret sharing.This guarantees that only authorized users can recover the control keys and then decrypt the outsourced data in an ownerspecified data lifetime.Besides confidentiality,data dynamics and deduplication are also achieved separately by adjustment of key derivation tree and convergent encryption.The analysis and experimental results show that our scheme can satisfy its security goal and perform the assured deletion with low cost.

Hepatitis B virus pre S1 deletion is related to viral replication increase and disease progression

AIM:To investigate the clinical implications of hepatitis B virus(HBV) pre S1 deletion.METHODS:We developed a fluorescence resonance energy transfer-based real-time polymerase chain reaction(RT-PCR) that can detect four genotypes(wild type, 15-bp, 18-bp and 21-bp deletion).The PCR method was used in two cohorts of Korean chronic HBV subjects with genotype C infections.Cohort Ⅰ included 292 chronic HBV subjects randomly selected from Cheju National University Hospital(Jeju, South Korea) or Seoul National University Hospital(Seoul, South Korea), and cohort Ⅱ included 90 consecutive chronic HBV carriers recruited from Konkuk University Hospital(Seoul, South Korea); the cohort Ⅱ patients did not have hepatocellular carcinoma or liver cirrhosis.RESULTS:The method proposed in this study identified 341 of 382 samples(89.3%).Deletion variants were identified in 100(29.3%) of the 341 detected samples.In both cohorts, the subjects with deletions had a significantly higher Hepatitis B virus e antigen(HBe Ag)-positive seroprevalence [cohort Ⅰ, wild(51.0%) vs deletion(75.0%), P < 0.001; cohort Ⅱ, wild(69.2%) vs deletion(92.9%), P = 0.002] and higher HBV DNA levels [cohort Ⅰ, wild(797.7 pg/m L) vs deletion(1678.9 pg/m L), P = 0.013; cohort Ⅱ, wild(8.3 × 108 copies/m L) vs deletion(2.2 × 109 copies/m L), P = 0.049], compared to subjects with wild type HBV.CONCLUSION:HBV genotype C pre S1 deletion may affect disease progression in chronic HBV subjects through an extended duration of HBe Ag seropositive status and increased HBV replications.

Abnormal Change of p53 Gene in Gastric and PrecancerousLesions and APC Gene Deletion in Gastric Carcinoma and Near Tissues

p53 gene mutation (exon4, 5, 6, 7, 8 and intron6) in gastric cancer and precancerous lesions and p53 gene (exon4 and ontron6), APC gene deletion in gastric carcinomas were studied by PCR/SSCP and PCR/RFLP- Results showed mutation rate of p53 in metaplasia, dysplasia and gastric carcinoma was 37. 5 % (3/8), 42. 11 % (8/19), 53. 33 (16/30) respectively- There was significant dif-ference among groups of metaplasia, dysplasia, cancer and normal controls. Noexon8 mutation was found in metaplasia and dysplasia, but 4 cases were found to have exon8 mutation in cancer group. It is suggested that exon8 mutation occurs at the late stage of gastric cancer, but exon 5, 6, 7 mutation occur in the course ofprecancerous lesion to cancer. Loss of heterozygosity (LOH) of exon4, intron6,APC was 47,37 % (9/19), 8. 73% (2/23), 16. 67 % (3/18) respectively. LOH of exon4 had something to do with poor differentiation, lymph node metastasis,depth of invasion- LOH of exon4 may be one of prognostic marker of gastric cancer. We are led to conclude that p53 gene mutation is an early event and perhaps work together with ras oncogene in gastric carcinogenesis

Novel approach to identifying the hepatitis B virus pre-S deletions associated with hepatocellular carcinoma

AIM: To develop a novel non-sequencing method for the detection of hepatitis B virus (HBV) pre-S deletion mutants in HBV carriers.

Angiotensin-converting Enzyme Gene Insertion/Deletion Polymorphism in Children with Henoch-Schonlein Purpua Nephritis

This study investigated the relationship between angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism and the occurrence, severity, prognosis of HSPN. The polymorphism of ACE gene in 103 HSPN cases and 100 healthy children was studied by using the polymerase chain reactions (PCR). Its relation to the clinical manifestation, pathological classification and prognosis of HSPN was analyzed accordingly. The results showed that: (1) there was a significantly higher frequency for DD genotype in HSPN children (P<0.01); (2) DD genotype was more frequently seen in HSPN children with gross hematuria and massive proteinuria (P<0.05), while DI genotype was more common in HSPN children group with renal insufficiency (P<0.05); (3) although mesangial proliferative lesion was most frequently observed in 21 biopsied HSPN children, and DD genotype frequency was still higher in children with severe pathology (Class Ⅲ Ⅳ); (4)II genotype was significantly frequent in HSPN children with complete remission in the follow-up of 32 HSPN children. It was concluded that the deletion allele of ACE gene might play a role, at least to some extent, in the occurrence, deterioration and progression in juvenile HSPN.

Deletion of cagA gene of Helicobacter pylori by PCR products

AIM: Cytotoxin-associated protein (antigen) A (CagA) plays an important role in Helicobacter pylori(H pylori) pathogenesis.Our aim was to obtain cagA mutant strains by a new mutation method so as to better understand the mechanism of CagA in epithelial cells. METHODS: In contrast with the traditional method using suicide plasmid,we constructed cagA- mutant strains directly with PCR products. The constructed mutant clones grew on selective media and allelic exchange was confirmed by Southern blot. Furthermore, two different transformation methods, electroporation, and natural transformation, were compared with regard to the efficiency of recombination. RESULTS:The mutation by PCR products could be completed within 3-5 d, and the recombination rate by electroporation and natural transformation was 4.02×10-8 and 1.03×10-9 respectively. Mutation rate by electroporation (4.02×10-8) was far higher than by natural transformation (1.03×10-9) (P= 0.000<0.005). CONCLUSION: cagA- mutant strains have been constructed, which is important for further study on the function of CagA in epithelial cells.A mutation method by directly using PCR products has been proved successful with a much higher mutation rate, and is easier,especially when in combination with electroporation.This method could be widely used in gene deletion of H pylori.