Light-dependent expression and accumulation of miR408-encoded peptide, miPEP408, is regulated by HY5 in Arabidopsis

Recent studies propose that primary transcripts of miRNAs (pri-miRNAs) contain small Open Reading Frames (ORFs) capable of encoding miRNA-encoded peptides (miPEPs). These miPEPs can function as transcriptional regulators for their corresponding pri-miRNAs, ultimately enhancing mature miRNA accumulation. Notably, pri-miR408 encodes the functional peptide miPEP408, regulating expression of miR408 and its target genes, providing plant tolerance to stresses. While miPEPs are crucial regulators, the factors governing them are have not been studied in detail. Here, we explored the light-dependent regulation of miPEP408 in Arabidopsis. Expression analysis during dark-light transitions revealed light-induced transcription and accumulation of the miPEP408. As the promoter of miR408 contains cis-acting elements responsible for binding to the bZIP-type transcription factor ELONGATED HYPOCOTYL5 (HY5), known for light-mediated regulation in plants, we studied its involvement in the regulation of miR408. Analysis of HY5 mutant (hy5-215), complemented line (HY5OX/hy5), and CONSTITUTIVE PHOTOMORPHOGENIC 1 mutant (cop1-4) plants supported HY5's positive regulation of miPEP408. Grafting and GUS assays further suggested the role of HY5 as a shoot-root mobile signal inducing light-dependent miPEP408 expression. This study underscores the regulatory impact of light on small peptides, exemplified by miPEP408, mediated by the key transcription factor HY5.

microRNA408 and its encoded peptide regulate sulfur assimilation and arsenic stress response in Arabidopsis

MicroRNAs (miRNAs) are small non-coding RNAs that play a central role in regulating various developmental and biological processes. The expression of miRNAs is differentially modulated in response to various biotic and abiotic stresses. Recent findings have shown that some pri-miRNAs encode small regulatory peptides known as microRNA-encoded peptides (miPEPs). miPEPs regulate the growth and development of plants by modulating corresponding miRNA expression; however, the role of these peptides under different stress conditions remains unexplored. Here, we report that pri-miR408 encodes a small peptide, miPEP408, that regulates the expression of miR408, its targets, and associated phenotype in Arabidopsis. We also report that miR408, apart from Plantacyanin (ARPN) and Laccase3 (LAC3), targets a glutathione S-transferase (GSTU25) that plays a role in sulfur assimilation and exhibits a range of detoxification activities with the environmental pollutant. Plants overexpressing miR408 showed severe sensitivity under low sulfur (LS), arsenite As(III), and LS + As(III) stress, while miR408 mutants developed using the CRISPR/Cas9 approach showed tolerance. Transgenic lines showed phenotypic alteration and modulation in the expression of genes involved in the sulfur reduction pathway and affect sulfate and glutathione accumulation. Similar to miR408 overexpressing lines, the exogenous application of synthetic miPEP408 and miPEP408OX lines led to sensitivity in plants under LS, As(III), and combined LS + As(III) stress compared to the control. This study suggests the involvement of miR408 and miPEP408 in heavy metal and nutrient deficiency responses through modulation of the sulfur assimilation pathway.

Internet Gaming Disorder: A Scoping Review and Future Direction

Objective: The massive popularity of digital gaming in recent decades has led to an inevitable surge in the use of digital technologies. This has made the younger population more prone to gaming, and causing an exponential rise in excessive video gaming among both children and adolescents. This scoping review summarizes and determines the scope, or coverage, of the body of empirical literature on Internet Gaming Disorder (IGD); published from 2010 to 2021. It was conducted to identify and map the available empirical evidence on IGD pertaining to its: prevalence, determinants, comorbidities and health consequences. Material and Methods: Literature searches were made in databases; including, Google Scholar, National Center for Biotechnology Information (NCBI) and PubMed to identify relevant articles published from 2010 to 2021. This was performed using preferred reporting items for systematic reviews and the meta-analyses technique (PRISMA) exclusion and inclusion criteria. Twenty-six empirical research studies are included in the present review. Results: There have been unexplored areas related to IGD since its introduction into the International Classification of Diseases (ICD-11) and the Diagnostic and Statistical Manual of Mental Disorders (DSM-5). Although its harmful impact on mental health and well-being remains untouched across the world, IGD is growing rapidly and calls for substantial worldwide consideration. Conclusion: Findings advance the understanding of IGD, identify gaps in research and propose future research directions. Research and innovations must focus on assessment, tools, prevention, intervention and treatment of IGD.

Ocimum sanctum, OscWRKY1, regulates phenylpropanoid pathway genes and promotes resistance to pathogen infection in Arabidopsis

KEY MESSAGE

OscWRKY1 from Ocimum sanctum positively regulates phenylpropanoid pathway genes and rosmarinic acid content. OscWRKY1 overexpression promotes resistance against bacterial pathogen in Arabidopsis. WRKY transcription factor (TF) family regulates various developmental and physiological functions in plants. PAL genes encode enzymes which are involved in plant defense responses, but the direct regulation of PAL genes and phenylpropanoid pathway through WRKY TF's is not well characterized. In the present study, we have characterized an OscWRKY1 gene from Ocimum sanctum which shows induced expression by methyl jasmonate (MeJA), salicylic acid (SA), and wounding. The recombinant OscWRKY1 protein binds to the DIG-labeled (Digoxigenin) W-box cis-element TTGAC[C/T] and activates the LacZ reporter gene in yeast. Overexpression of OscWRKY1 enhances Arabidopsis resistance towards Pseudomonas syringae pv. tomato Pst DC3000. Upstream activator sequences of PAL and C4H have been identified to contain the conserved W-box cis-element (TTGACC) in both O. sanctum and Arabidopsis. OscWRKY1 was found to interact with W-box cis-element present in the PAL and C4H promoters. Silencing of OscWRKY1 using VIGS resulted in reduced expression of PAL, C4H, COMT, F5H and 4CL transcripts. OscWRKY1 silenced plants exhibit reduced PAL activity, whereas, the overexpression lines of OscWRKY1 in Arabidopsis exhibit increased PAL activity. Furthermore, the metabolite analysis of OscWRKY1 silenced plants showed reduced rosmarinic acid content. These results revealed that OscWRKY1 positively regulates the phenylpropanoid pathway genes leading to the alteration of rosmarinic acid content and enhances the resistance against bacterial pathogen in Arabidopsis.

Efficacy and Safety of Fluticasone Furoate and Oxymetazoline Nasal Spray: A Novel First Fixed Dose Combination for the Management of Allergic Rhinitis with Nasal Congestion

Objective

To compare the efficacy and safety of a fixed dose combination of Fluticasone Furoate and Oxymetazoline Hydrochloride Nasal Spray 27.5/50 mcg (FDC) with Fluticasone Furoate Nasal Spray 27.5 mcg (Fluticasone) in the management of allergic rhinitis.

Patients and Methods

A prospective, randomized, double-blind, two-arm, active-controlled, parallel, multicenter, comparative clinical study was conducted in patients with allergic rhinitis aged 18 years and above having moderate-to-severe nasal congestion.

Results

A total of 250 patients were randomized (1:1) to receive either the FDC or Fluticasone alone in a dose of two sprays in each nostril once daily at night. There was a significantly (P<0.001) greater reduction in night-time Total Nasal Symptom Score with the FDC as compared to Fluticasone at all the time points starting from as early as day 3 and sustained till the end of treatment (Day 28) (Day 3: −3.1 vs −2.2; Day 7: −4.0 vs −3.4; Day 14: −5.7 vs −5.0; Day 28: −7.0 vs −6.4). A significantly greater number of patients (P<0.05) had complete relief in Nasal Congestion with the FDC (44.7%) as compared to Fluticasone (26.8%). Both the study medications were well tolerated by all the patients. The proportion of patients showing worsening of symptoms (rebound congestion/rhinitis medicamentosa) after stoppage of medication was similar in both groups (P>0.05).

Conclusion

The FDC was superior to Fluticasone alone in relieving the nasal congestion and reduction of Total Nasal Symptom Score in allergic rhinitis patients with moderate-to-severe nasal congestion when administered once daily in the evening. Oxymetazoline when used along with the nasal steroid in a once daily dose does not cause rebound congestion and rhinitis medicamentosa even after long-term continuous use of 28 days.

Effect of nanoparticle on rheological properties of surfactant-based nanofluid for effective carbon utilization: capturing and storage prospects

Previous studies have shown insufficient dispersion and thermal stability of nanofluids for high-temperature carbon capture and storage applications. Compared to the other NPs, TiO₂ nanofluids exhibit superior stability due to their high zeta potential. In previous studies, TiO₂ nanofluids have shown superior performance in heat transfer and cooling applications along with importing the stability of other nanofluids like SiO₂ in form of nanocomposites. Therefore, in this study, a nanofluid formulation consisting of titania nanofluid in a base solution of ethylene glycol (EG) with different co-stabilizers such as surfactants was synthesized for better dispersion stability, enhanced electrical, and rheological properties especially for the use in high-temperature industrial applications which include carbon capture and storage along with enhanced oil recovery. The formulated nanofluid was investigated for stability using dynamic light scattering (DLS) study and electrical conductivity. Additionally, the formulated nanofluid was also examined for thermal stability at high temperatures using an electrical conductivity study followed by rheological measurements at 30 and 90 °C. At a high temperature, the shear-thinning behavior of EG was found highly affected by shear rate; however, this deformation was controlled using TiO₂ nanoparticles (NPs). Furthermore, the role of surfactant was also investigated on dispersion stability, electrical conductivity followed by viscosity results, and it was found that the nanofluid is superior in presence of anionic surfactant sodium dodecyl sulfate (SDS) as compared to nonionic surfactant Triton X-100 (TX-100). The inclusion of ionic surfactant provides a charged layer of micelles surrounding the core of a NP and it produced additional surface potential. Consequently, it increases the repulsive force between two adjacent NPs and renders a greater stability to nanofluid while nonionic surfactant allowed monomers to adsorb on the surface of NP via hydrophobic interaction and enhances the short-range interparticle repulsion, to stabilize nanofluid. This makes titania nanofluid suitable for widespread high-temperature applications where conventional nanofluids face limitations. Finally, the application of the synthesized titania nanofluids was explored for the capture and transport of CO₂ where the inclusion of the anionic surfactant was found to increase the CO₂ capturing ability of titania nanofluids by 140-220% (over the conventional nanofluid) while also showing superior retention at both investigated temperatures. Thus, the study promotes the role of novel surfactant-treated titania nanofluids for carbon removal and storage and recommends their applications involving carbonated fluid injection (CFI) to carbon utilization in oilfield applications.

Light-regulated expression of terpene synthase gene, AtTPS03, is controlled by the bZIP transcription factor, HY5, in Arabidopsis thaliana

The terpenoid pathway serves as an essential source of all isoprenoid precursors and metabolites that are of great pharmacological importance. The major enzymes for the synthesis of these diverse molecules is the terpene synthases (TPSs), which catalyse the final step of the synthesis of the important secondary products, the terpenes. Previous studies have reported that the various environmental factors, including light govern the synthesis of terpenoids. However, the molecular components and steps involved in the regulation of synthesis of these molecules have not been studied in detail. In this study, we report that the light regulates the expression of the members of terpene synthase gene family in Arabidopsis thaliana. We demonstrate that ELONGATED HYPOCOTYL (HY5), a basic leucine zipper transcription factor, plays a crucial role in light-mediated transcriptional regulation of terpene synthase, AtTPS03. Expression analysis using hy5-215 mutant and HY5 over-expression lines revealed that HY5 acts as a positive regulator of AtTPS03. Additionally, studies including AtTPS03 Promoter::reporter transgenic lines in wild-type and hy5-215, as well as electrophoretic mobility shift assay (EMSA), suggest an interaction of HY5 with the AtTPS03 promoter. Together, our analysis indicate the requirement for HY5 for light-mediated regulation of AtTPS03 for the terpenoid biosynthesis in Arabidopsis.

3'O-Methyltransferase, Ps3'OMT, from opium poppy: involvement in papaverine biosynthesis

Using, in silico, in vitro and in planta functional assays, we demonstrate that Ps3'OMT, an 3'-O methyl transferase is linked to papaverine biosynthesis in opium poppy. Papaverine, one of the benzylisoquinoline alkaloids (BIA) synthesized in the medicinally important plant, Papaver somniferum, is known for the potent pharmacological properties. Papaverine biosynthesis has remained debatable as two different pathways, NH (involving N-desmethylated intermediates) and the NCH₃ (involving N-methylated intermediates), have been proposed. In addition, there are several intermediate steps in both the proposed pathways that are not very well characterized in terms of specific enzymes. In this study, we report the identification and functional characterization of 3'O-methyltransferase (Ps3'OMT) which might participate in the 3'O-methylation of the intermediates in the papaverine biosynthesis. Comparison of transcript and metabolite profiles of high and low papaverine producing cultivar revealed the occurrence of a 3'O-methyltransferase, Ps3'OMT, which was abundant in aerial organs and shared 72% identity with the GfLOMT7 predicted to have 3'OMT activity. In silico studies based on homology modeling, docking and MD simulations predicted (S)-norlaudanine as the potential substrate forming a stable complex with Ps3'OMT. Suppression of Ps3'OMT through virus-induced gene silencing resulted in a remarkable decrease in the level of papaverine in comparison to control plants. The characterization of the functionally unique Ps3'OMT involved in BIA metabolism suggests an involvement of the NH pathway leading to papaverine biosynthesis.

RMP exposure is lower in HIV-infected TB patients receiving intermittent than daily anti-tuberculosis treatment

We compared the pharmacokinetics of rifampicin (RMP) during daily and intermittent (thrice weekly) anti-tuberculosis treatment in human immunodeficiency virus infected tuberculosis patients. Patients treated with a thrice-weekly regimen had significantly lower plasma peak concentration, area under the time concentration curve from 0 to 24 h and higher oral clearance of RMP than those treated with the daily regimen. The median values were respectively 3.7 and 6.4 μg/ml (P < 0.001), 20.7 and 29.4 μg/ml.h (P = 0.03) and 21.7 and 15.3 ml/min (P = 0.03).

Number of sputum specimens during treatment follow-up of tuberculosis patients: two or one?

SETTING

National Institute for Research in Tuberculosis clinics in Chennai and Madurai, India.

OBJECTIVE

To examine the pattern of serial smears (negative-negative [NN], negative-positive [NP], positive-negative [PN], positive-positive [PP]) during treatment follow-up of culture-confirmed new smear-positive tuberculosis (TB) patients, and the proportion of culture-negatives in each category.

DESIGN

We reviewed the records and extracted follow-up smear (fluorescent microscopy) and culture (Löwenstein-Jensen) results of patients enrolled in clinical trials from January 2000 to August 2012 and treated with the Category I regimen (2EHRZ3/4HR3). Data entry and analysis were performed using EpiData.

RESULTS

Among 520 patients (176 infected with the human immunodeficiency virus), the proportions of culture-negative patients with NN, discordant (PN or NP) and PP patterns were approximately 98%, 80% and 40%, respectively. The smear-positive culture-negative phenomenon was more frequent in follow-up smear results graded 1+, followed by 2+ and 3+.

CONCLUSION

There is justification for discontinuing the examination of second specimens during treatment follow-up among TB patients. However, a positive result on the first smear needs to be confirmed by a second positive result before making clinical management decisions. The World Health Organization may need to reconsider its recommendation on this issue.

Are we justified in treating for multidrug-resistant tuberculosis based on positive follow-up smear results?

SETTING

National Institute for Research in Tuberculosis, India.

OBJECTIVE

To assess, among new culture-confirmed smear-positive pulmonary tuberculosis (TB) patients, the proportion of follow-up smear-positives that were culture-negative (S+C-) by month of follow-up examination, human immunodeficiency virus (HIV) status, pre-treatment drug susceptibility status and smear grading.

DESIGN

We extracted follow-up smear (fluorescence microscopy) and culture (Löwenstein-Jensen) results of patients enrolled in clinical trials from January 2000 to August 2012 and treated with the WHO Category I regimen (2EHRZ3/4HR3).

RESULTS

Of 520 patients, including 176 who were HIV-infected, respectively 199, 81, 47 and 43 were smear-positive at months 2, 4, 5 and 6; of these, respectively 138 (69%), 62 (75%), 32 (68%) and 27 (63%) were culture-negative. The S+C- phenomenon was more pronounced among '1+ positive' patients than in 2+ or 3+ positive patients and in 'pan-susceptible' patients than in those with any resistance, and did not vary by HIV status.

CONCLUSION

Nearly two thirds of patients with follow-up smears positive at months 5 and 6 were culture-negative. Starting multidrug-resistant TB (MDR-TB) treatment empirically based on smear results, even in resource-limited settings, is incorrect and can have hazardous consequences. There is an urgent need to revisit the WHO recommendation concerning empirical MDR-TB treatment.

p190-B RhoGAP regulates the functional composition of the mesenchymal microenvironment

Hematopoiesis is regulated by components of the microenvironment, so-called niche. Here, we show that p190-B GTPase-activating protein (p190-B) deletion in mice causes hematopoietic failure during ontogeny, in p190-B(-/-) fetal liver and bones, and in p190-B(+/-) adult bones and spleen. These defects are non-cell autonomous, as we previously showed that transplantation of p190-B(-/-) hematopoietic cells into wild-type (WT) hosts leads to normal hematopoiesis. Coculture of mesenchymal stem (MSC)/progenitor cells and wild-type bone marrow (BM) cells reveals that p190-B(-/-) MSCs are dysfunctional in supporting hematopoiesis owing to impaired Wnt signaling. Furthermore, p190-B loss causes alteration in BM niche composition, including abnormal colony-forming unit (CFU)-fibroblast, CFU-adipocyte and CFU-osteoblast numbers. This is due to altered MSC lineage fate specification to osteoblast and adipocyte lineages. Thus, p190-B organizes a functional mesenchymal/microenvironment for normal hematopoiesis during development.

Studies on the Preparation and Evaluation of Chitosan Nanoparticles containing Cytarabine

The activity of cytarabine was decreased by its rapid deamination to the biologically inactive metabolite uracil arabinoside. This rapid deamination is the reason for the ongoing research for effective formulation of cytarabine that can not be deaminated and exhibit better pharmacokinetic parameters. Protection of cytarabine from fast degradation and elimination was investigated by encapsulating the drug into chitosan nanoparticles. Cytarabine loaded nanoparticles prepared by ionotropic gelation were characterized by SEM and was found to in the range of 200 nm.The mechanism by which drug is being released is non-Fickian(anomalous) solute diffusion mechanism. It is evident from the result that initial burst release was retarded or delayed due to adsorption of coating material. The in vivo biodistribution study results showed that the nanoparticles were having better distribution of drug compared to free drug in different organs like spleen, lungs, kidney etc.

Comparison of Visante and slit-lamp anterior segment optical coherence tomography in imaging the anterior chamber angle

AIMS

To compare the diagnostic performance of two anterior segment optical coherence tomography (AS-OCT) devices in assessing the anterior chamber angle (ACA).

METHODS

Visante-OCT and slit-lamp-OCT (SL-OCT) were performed on 101 patients by a single operator. The AS-OCT images were processed by customised 'dewarping' software and assessed by two glaucoma specialists masked to clinical findings. A closed ACA was defined by the presence of contact between the iris and angle anterior to the scleral spur. Measurements of the ACA, anterior chamber depth (ACD), and pupil diameter were analysed. Gonioscopy was performed by another examiner masked to AS-OCT findings.

RESULTS

Qualitative analysis could be carried out in 83 (83%) eyes and quantitative analysis in 61 (60%) eyes. A closed angle in at least one quadrant of the eye was observed in 30 eyes with gonioscopy; Visante-OCT imaging identified 29 of 30 (97%) and SL-OCT imaging identified 27 of 30 (90%) of these eyes (P=0.50, McNemar test). Visante-OCT detected more eyes with at least one closed quadrant than SL-OCT (55 vs46 eyes, respectively, P=0.01). Overall, SL-OCT had better agreement with gonioscopy than with Visante-OCT. Both AS-OCTs showed good agreement for ACD measurements; however, SL-OCT tended to provide consistently higher ACA measurements and smaller pupil diameters than did Visante-OCT.

CONCLUSIONS

Both AS-OCT devices detected most of the eyes with closed ACA on gonioscopy. However, Visante-OCT detected more closed ACAs than did SL-OCT. The better agreement between SL-OCT and gonioscopy is likely because of the use of visible light during both examinations. The ACA measurements obtained with each device are not interchangeable.

Right ventricular diastolic function after repair of tetralogy of Fallot

The objective of this study was quantitate diastolic dysfunction in the postoperative phase of tetralogy of Fallot (TOF) and to correlate it with the type of surgical procedure and clinical parameters. Fifty consecutive patients (mean age, 5.0 years; mean weight, 13.5 kg), operated for TOF during the period November 2004 to May 2005, were prospectively studied [infundibular resection, 23; infundibular resection and transannular patch (TAP), 19; right ventricle --> pulmonary artery conduit, 8). Detailed echocardiography was done on postoperative days 3 and 9 with a focus on Doppler indices of right ventricular (RV) function, Antegrade late diastolic flow in the right ventricular outflow tract (RVOT) was taken as the marker of restrictive RV physiology. The previous parameters were correlated to the type of surgery and clinical indices of RV dysfunction. There was no mortality. Twenty-four patients showed restrictive RV physiology. This finding correlated with lower values of E/A ratio (0.98 +/- 0.17 vs 1.33 +/- 0.49, p < 0.002), tricuspid valve E-wave deceleration time (86.9 +/- 21.7 vs 151.4 +/- 152 msec, p < 0.05), index of myocardial performance (0.15 +/- 0.06 vs 0.26 +/- 0.09, p < 0.001), isovolumic relaxation time (19.4 +/- 17 vs 39+/-30 msec, p < 0.009), and a higher central venous pressure (15.1 +/- 1.5 vs 12.7 +/- 1.9, p < 0.001). Restrictive RV physiology correlated with prolonged intensive case unit (ICU) stay (5.1 +/- 3.7 vs 2.8 +/- 2 days, p < 0.015), longer duration of inotropic support (108.3 +/- 56.2 vs 55.5 +/- 28.3 hours, p < 0.02), and higher dosage of diuretics. RV diastolic dysfunction is demonstrable by Doppler echocardiography in the first week following surgery for TOF and tends to be worse with TAP. Restrictive physiology demonstrated by RVOT pulse Doppler predicts longer duration of inotropic support, prolonged ICU stay, and higher dosage of diuretics.

Antioxidant and antimicrobial activities of Bauhinia racemosa L. stem bark

The present study was carried out to evaluate the antioxidant and antimicrobial activities of a methanol extract of Bauhinia racemosa (MEBR) (Caesalpiniaceae) stem bark in various systems. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. The antioxidant activity of the methanol extract increased in a concentration-dependent manner. About 50, 100, 250, and 500 microg MEBR inhibited the peroxidation of a linoleic acid emulsion by 62.43, 67.21, 71.04, and 76.83%, respectively. Similarly, the effect of MEBR on reducing power increased in a concentration-dependent manner. In DPPH radical scavenging assays the IC50 value of the extract was 152.29 microg/ml. MEBR inhibited the nitric oxide radicals generated from sodium nitroprusside with an IC50 of 78.34 microg/ml, as opposed to 20.4 microg/ml for curcumin. Moreover, MEBR scavenged the superoxide generated by the PMS/NADH-NBT system. MEBR also inhibited the hydroxyl radical generated by Fenton's reaction, with an IC50 value of more than 1000 microg/ml, as compared to 5 microg/ml for catechin. The amounts of total phenolic compounds were also determined and 64.7 microg pyrocatechol phenol equivalents were detected in MEBR (1 mg). The antimicrobial activities of MEBR were determined by disc diffusion with five Gram-positive, four Gram-negative and four fungal species. MEBR showed broad-spectrum antimicrobial activity against all tested microorganisms. The results obtained in the present study indicate that MEBR can be a potential source of natural antioxidant and antimicrobial agents.

Sensitive detection of GM1 lipid rafts and TCR partitioning in the T cell membrane

The cholesterol-rich lipid rafts on T cell membrane play important role in the formation of T cell receptor (TCR) signalosome upon receptor ligation. Analytical studies on the kinetics of lipid rafts formation and recruitment of protein receptors to lipid rafts are still limited by the use of a large number of cells. Herein, we describe a strategy for detecting fine alterations in the amount and distribution of glycosphingolipid (GM1) lipid rafts, and in the formation of GM1-TCR complexes in detergent-insoluble and -soluble compartments of the T cell membrane from a relative low number of cells. Using this strategy, we found that the GM1 moiety was physically associated with TCR in both detergent-insoluble and -soluble fractions. Shortly after ligation of CD3/TCR complex with a soluble CD3- epsilon mAb, the TCR was found mainly in the detergent-soluble fraction of the T cell membrane.

Generation of monoclonal antibody CIBCgp185 against C-erbB-2 oncoprotein and its clinical evaluation

The C-erbB-2 proto-oncogene encodes the production of a cell surface receptor protein, with tyrosine kinase activity. Over expression of this gene either due to gene amplification and/or increased transcription has been observed and has been correlated with poor prognosis in patients with Breast (10-33%) and ovarian (20-33%) cancers. The very low levels of expression of C-erbB-2 by normal tissues makes this receptor a potential target for diagnosis and therapy with Monoclonal antibodies raised against its extracellular domain. One such monoclonal antibody designated as CIBCgp185 of IgG2a isotype has been generated in our laboratory using BT474 breast carcinoma cell line as immunogen. This monoclonal antibody immunoprecipitated a 185 KD glycoprotein. The specificity of this antibody was confirmed by the formation of a single discrete band and positive reaction with BT474 antigen in Western blot and Dot blot respectively. Flowcytometric analysis performed using various cancer cell lines revealed that this Monoclonal antibody exhibited high binding affinity with BT474 and SKBR3 cells whichoverexpresses C-erbB-2. By immunoperoxidase test, this antibody stained specifically the tumor cell membrane in frozen tissue sections of breast and ovarian tumors indicating overexpression of the C-erbB-2 product. All these results well correlated with those obtained using a control antibody ICR12, an anti-C-erbB-2 antibody. These studies clearly indicate that Monoclonal antibody CIBCgp185 might prove useful to identify tumors with over expression of C-erbB-2 which are often associated with poor prognosis and early recurrence.

Molecular biology of the channel catfish gonadotropin receptors: 2. Complementary DNA cloning, functional expression, and seasonal gene expression of the follicle-stimulating hormone receptor

Molecular cloning of the channel catfish FSH receptor is reported together with temporal changes in the gene expression throughout a reproductive cycle. A cDNA encoding the receptor was isolated from the testis using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) procedures. The cDNA coded for a 662-amino acid protein that was most identical (51%-59%) to salmon gonadotropin receptor I and the FSH receptors of higher vertebrates, and less identical to LH receptors and thyrotropin receptors (45%-49% and 46%-47%, respectively). In addition, PCR analysis of the genomic DNA showed the absence of the LH receptor-specific intron. Expression of the channel catfish FSH receptor gene was highly restricted to the testis and ovary, except for a low-level expression in the spleen. Transfected COS cells expressed an active recombinant receptor as determined by the ligand-specific activation of a cAMP-responsive reporter gene (luciferase). The recombinant receptor was activated by human FSH and, to a small extent, hCG. Seasonal changes in the ovarian expression of the FSH receptor gene, examined by measuring the transcript abundance by quantitative real-time RT-PCR, showed a rise around the time of onset of ovarian recrudescence and a decrease prior to spawning. This pattern of seasonal expression of FSH receptor differs significantly from that of the LH receptor, which we reported recently. The differential expression of the two gonadotropin receptor genes, in addition to the differential secretion of the gonadotropic hormones, seem to be critical for the regulation of steroidogenesis and other gonadal physiological processes.

Piscine glycoprotein hormone (gonadotropin and thyrotropin) receptors: a review of recent developments

Similar to the higher vertebrates, the pituitary in bony fishes express three glycoprotein hormones: thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH) and luteinizing hormone (LH). In addition to the appropriate secretion of these hormones, the timely and quantitative expression of their specific receptors (TSHR, FSHR and LHR) in the target tissues is an essential requirement for their physiological action. In fishes that constitute a very diverse group of vertebrates, there are only a few published reports of primary structure of these receptors although other examples have been communicated briefly. This review will summarize these reports as well as to describe the insights gained from what is known about the mammalian receptors. The structural organization of the fish receptors (as deduced from the encoding cDNAs) is highly homologous to the higher vertebrate receptors in that there is a 7-pass transmembrane region and an N-terminal extracellular domain, which contributes to ligand specificity. In mammals, the FSHR and the TSHR genes are composed of 10 exons whereas the LHR gene is composed of 11 exons. The position of the 'extra intron' is conserved in the catfish LHR gene. In the mammals, the transmembrane domain of each of the three glycoprotein hormone receptors is encoded by a single exon, however, in the salmon genes and homologous invertebrate genes, this portion of the receptor is encoded by multiple exons. In general, the tissue-specific expression of these receptors is similar to that seen in mammals, however, the gonadal expression of TSHR in the striped bass and sunrise sculpin and the renal expression of LHR in the channel catfish are unique.

Recombinant perciform GnRH-R activates different signaling pathways in fish and mammalian heterologous cell lines

Perciforms have three forms of gonadotropin-releasing hormone (GnRH) in their brain. All three GnRHs are potent secretogogues for luteinizing hormone (LH) from the pituitary. The pivotal role of GnRH-R-GnRH interactions in reproductive homeostasis is well established; however, there is a paucity of information on how a GnRH-R responds to the three endogenous GnRH forms in a perciform species. In this study, a recombinant pituitary GnRH-R from striped bass (stb) was expressed in a mammalian cell line (COS-7) and a fish cell line (CHSE-214). Activation of the signaling pathways was monitored by reporter gene (luciferase) based assays, which were specific for cAMP-PKA or Ca 2+/calmodulin kinase (activated via c-fos promoter) signaling pathways. The stbGnRH-R expressed in two different cell lines triggered different downstream signaling in response to the treatments with chicken (c) GnRH II. Interestingly, when endogenous GnRHs were used in combinations, the luciferase activity was significantly attenuated in transfected CHSE-214 cells.

Molecular biology of channel catfish gonadotropin receptors: 1. Cloning of a functional luteinizing hormone receptor and preovulatory induction of gene expression

There is little known about the molecular biology of piscine gonadotropin receptors, and information about gene expression during reproductive development is particularly lacking. We have cloned the LH receptor (LHR) in the channel catfish (cc), and examined its gene expression throughout a reproductive cycle. A cDNA encoding the receptor was isolated from the testis using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends procedures. It encoded a 696-amino acid protein that showed the greatest homology (46-50% identity) with the known LHRs and lesser similarity with FSH receptors and thyroid-stimulating hormone receptors (44-47% and 42-44% identity, respectively). In addition, two characteristics unique to the LHRs were conserved in the cloned receptor and the encoding gene: presence of an intron corresponding to intron 10 in mammals and turkey and occurrence of a double cysteine residue in the cytoplasmic tail for potential palmitoylation. The ccLHR gene was well expressed in the gonads and kidney and merely detectable in the gills, muscle, and spleen. The isolated cDNA encoded an active ccLHR protein, as the recombinant receptor expressed in COS7 cells activated a cAMP response element-driven reporter gene (luciferase) upon exposure to hCG in a dose-dependent manner. Seasonal changes in the ovarian expression of the ccLHR gene, as examined by measuring the transcript abundance by quantitative real-time RT-PCR, remained rather low during most of the reproductive cycle but was acutely induced around the time of spawning. This pattern of expression correlates well with the reported expression of its ligand (LH) in fishes and concurs with the notion that LH is a key regulator of the periovulatory maturational events.

Lipid peroxidation and diabetic retinopathy

The high level of glucose in blood for a long duration is the main cause of the development of retinopathy. So yearly screening of patients newly diagnosed with NIDDM diabetes is recommended because rare cases of treatable diabetic retinopathy have occurred early in one course of NIDDM diabetes. Hyperglycaemia leads to non-enzymatic glycosylation of proteins and HbA1C was found increased. Antioxidants such as GSH and SOD level is found decreased in retinopathy conditions due to the higher lipid peroxidation, which is evident from high MDA and DC values. So it can be clearly stated that increase in the free radical by hyperglycaemia, lipid peroxidation and advanced glycosylation endproducts along with decreased antioxidants are the causative agents for the development of retinopathy.

Cloning and functional expression of a thyrotropin receptor from the gonads of a vertebrate (bony fish): potential thyroid-independent role for thyrotropin in reproduction

The thyroid stimulating hormone receptor (TSHR) mediates the pituitary control of the development, growth and function of the thyroid. The expression of the gene encoding this receptor is known only in the thyroid, lymphocytes, fibroblasts, retro-orbital tissue and fat cells. We have cloned a TSHR from the gonads of a non-mammalian vertebrate, a bony fish (striped bass, Morone saxatilis) in the course of our search for gonadotropin receptors (follicle stimulating hormone receptor, FSHR and luteinizing hormone receptor, LHR). RT-PCR analysis demonstrated that the striped bass TSHR (stbTSHR) transcripts were abundant in both the thyroid and gonads and detectable in skeletal muscle, heart and brain tissues. The stbTSHR cDNA encoded a 779-amino acid glycoprotein hormone receptor with much higher homology (57-59%) to the mammalian TSH receptors than the mammalian LH receptors (47-49%) and FSH receptors (47%), and salmon and catfish gonadotropin receptors (42-45%). There was a TSHR-specific insertion in the extracellular domain as seen in mammalian receptors. Moreover, PCR analysis of genomic DNA indicated the absence of the LHR-specific intron in the striped bass TSHR gene. Recombinant stbTSHR expressed in COS1 cells activated reporter genes (luciferase) driven by either a cAMP response element or the c-fos promoter in response to bovine TSH, stbLH or hCG, but not human FSH. In situ hybridization studies revealed the presence of stbTSHR transcripts in the gametes but not in the follicular cells. This pattern of expression is unique and suggests a direct, albeit unknown, role for TSH in gamete physiology.

Dienophilic behavior of the vinylic (C=C) and the carbonyl (C=O) bonds of ketenes in reactions with 1,3-diazabuta-1,3-dienes

[reaction: see text] Ab initio and density functional studies (DFT) on cycloaddition reactions of 1,3-diazabuta-1,3-dienes with ketenes are reported. The vinylic (C=C) and the carbonyl (C=O) units of the ketenes are found to participate in concerted asynchronous [4 + 2] cycloaddition reactions. The transition states (3t, 4t, and 7t) for these paths have been located on the PE surface at the correlated levels of ab initio calculations. A reasonable mechanism for the formation of [4 + 2] and [2 + 2] adducts is presented.

Chaperone-like activity of a synthetic peptide toward oxidized gamma-crystallin

alphaA-Crystallin can function like a molecular chaperone. We recently reported that the alphaA-crystallin sequence, KFVIFLDVKHFSPEDLTVK (peptide-1, residues 70-88) by itself possesses chaperone-like (anti-aggregating) activity during a thermal denaturation assay. Based on the above data we proposed that the peptide-1 sequence was the functional site in alphaA-crystallin. In this study we investigated the specificity of peptide-1 against gamma-crystallin aggregation in the presence of H2O2 and CuSO4. Peptide-1 was able to completely protect against the oxidation-induced aggregation of gamma-crystallin. Removal of N-terminal Lys or the replacement of Lys with Asp (DFVIFLDVKHFSPEDLTVK, peptide-2) did not alter the anti-aggregation property of peptide-1. However, deletion of KF residues from the N-terminus of peptide-1 resulted in a significant loss of its anti-aggregation property. Bio-gel P-30 size-exclusion chromatography of gamma-crystallin incubated with peptide-2 under oxidative conditions revealed that a major portion of the peptide elutes in the void volume region along with gamma-crystallin, suggesting the binding of the peptide to the protein. Peptide-1 and -2 were also able to prevent the UV-induced aggregation of gamma-crystallin. These data indicate that the same amino acid sequence in alphaA-crystallin is likely to be responsible for suppressing the heat-denatured, oxidatively modified and UV-induced aggregation of proteins.

Synthesis and characterization of a peptide identified as a functional element in alphaA-crystallin

Eye lens alpha-crystallin is a member of the small heat shock protein (sHSP) family and forms large multimeric structures. Earlier studies have shown that it can act like a molecular chaperone and form a stable complex with partially unfolded proteins. We have observed that prior binding of the hydrophobic protein melittin to alpha-crystallin diminishes its chaperone-like activity toward denaturing alcohol dehydrogenase, suggesting the presence of mutually exclusive sites for these proteins in alpha-crystallin. To investigate the mechanism of the interaction between alpha-crystallin and substrate proteins, we determined the melittin-binding sites in alpha-crystallin by cross-linking studies. Localization of melittin-binding sites in alpha-crystallin resulted in the identification of RTLGPFYPSR and FVIFLDVKHFSPEDLTVK of alphaA-crystallin and FSVNLDVK of alphaB-crystallin as the chaperone sites. Of these sites, FVIFLDVKHFSPEDLTVK and FSVNLDVK were identified earlier as 1,1'-bi(4-anilino) naphthalene-5,5'-disulfonic acid (bis-ANS)-binding hydrophobic sites. Here we also report the synthesis and characterization of the peptide, KFVIFLDVKHFSPEDLTVK, having the melittin as well as bis-ANS-binding sequence of alphaA-crystallin. We show that this peptide has characteristics similar to that of alphaA-crystallin by in vitro thermal aggregation assay, gel filtration study, CD spectroscopy, and bis-ANS interaction studies. The peptide sequence corresponds to the beta3 and beta4 region present in the alpha-crystallin domain of sHSP 16.5. We hypothesize that the alpha-crystallin domain in other sHSPs may have a similar function and would likely possess the anti-aggregation property even when separated from the native protein.

Serotyping of Streptococcus pneumoniae by coagglutination with 12 pooled antisera

We report on the performance of a recently introduced commercial chessboard method using 12 antisera, in comparison with that of the 55-antiserum panel used in determining the serogroups and types (SGTs) of Streptococcus pneumoniae, both of which were carried out by a coagglutination technique. Of a total of 150 strains of S. pneumoniae studied, 135 (90%) belonged to the SGTs represented in the 23-valent pneumococcal vaccine; of these, 130 (96.3%) were identified as the same SGTs by both typing methods. The remaining five strains showed cross-reactivity with more than two pools by the chessboard method, but could be assigned to a single SGT by the Quellung test. The 96.3% concordance of the chessboard method suggests it can be adopted for determination of the SGTs of S. pneumoniae in laboratories.

Studies on proteases and alpha-macroglobulin activity in amphibian blood plasma

Frog plasma effectively hydrolysed the synthetic chromogenic substrates, H-D-Glu-Gly-Arg-p-nitroanilide (S-2444), benzoyl-Ile-Glu-Gly-Arg-p-nitroanilide (S-2222) and acetyl-Ile-Glu-Gly-Arg- p-nitroanilide (S-2423), all sensitive substrates for trypsin. Moderate hydrolytic activities was observed with H-D-Phe-Pip-Arg-p-nitroanilide (S-2238, substrate for thrombin) and H-D-Pro-Phe-Arg-p-nitroanilide (S-2302, substrate for plasma kallikrein). Frog plasma contained moderate alpha-macroglobulin activity. When plasma was incubated at 37 degrees C, the macroglobulin activity decreased in a time dependent manner while only a moderate decrease in the protease activity was observed. Ten fold dilution of plasma with 0.1 M phosphate buffer, pH 7.6 prevented the inherent loss of macroglobulin activity but it had no effect on protease activity. Dye ligand chromatography of the plasma on red Sepharose revealed that bulk of alpha-macroglobulin activity along with minor proteolytic activity (S-2222 hydrolysis) was present i the washings. On the other hand, about one third of the alpha-macroglobulin activity and bulk of the protease activity was bound to the column and were eluted with 1.5 M NaCl. alpha-Macroglobulin activity in red Sepharose washings and elutions on chromatography on Sephadex G-200, was eluted in two regions with Ve/Vo value of 1.33 and 1.08, respectively.

Peritoneal dialysis for acute renal failure in infants: a comparison of three types of peritoneal access

Peritoneal access for peritoneal dialysis (PD) poses a significant problem in infants due to their small size and can result in considerable morbidity and occasional mortality. This study was carried out to compare the complications associated with three different types of PH catheters for intermittent PD. A total of 79 session of PD were given to 51 infants with acute renal failure. Twenty-nine infants received 1, 18 received 2 and 2 infants received 3 and 4 sessions of PD, respectively. For PD access an intravenous cannula was used in 36, stylet catheter in 18, and guide wire inserted femoral vein catheter in 25 procedures. Percentage reduction of serum creatinine per PD session was comparable in infants being dialysed with different types of PD access. Local puncture site and intraperitoneal bleed were associated with the use of a stylet catheter during 4 procedures each (22.2%). Catheter blockade was commonest with the intravenous cannula (22.2%), followed by guide wire inserted femoral vein catheter (16%), and was least with the stylet catheter (5.5%). Total mechanical complications were lower with guide wire inserted femoral vein catheter (16%) as compared to intravenous cannula (25%) and stylet catheter (66%) (p < 0.05). There were 4 episodes of peritonitis (5.0%), 3 bacterial and 1 fungal. Although peritonitis was more common with intravenous cannula (8.3%) than guide wire inserted catheter (4%) and stylet catheter (nil), the difference was not statistically significant. Total complications including mechanical and infective were least with guide wire inserted femoral vein catheter (20%), followed by intravenous cannula (33%) and stylet catheter (66%) (p < 0.05). Of 51 infants, 20 died (39.0%). The PD procedure per se resulted in mortality in 2 cases, 1 because of massive intraperitoneal bleed due to stylet induced injury of an intra abdominal blood vessel and the other due to fungal peritonitis. To conclude, of the three types of access for intermittent PD, complications related to the PD procedure are the least with guide wire inserted femoral vein catheter.

Bidirectional Glenn shunt: a step in the right direction

Bidirectional Glenn (BDG) shunt was carried out in 14 patients (age range 1.5-22 years; mean 9.3 years) for a variety of congenital cyanotic heart diseases with decreased pulmonary blood flow. Postoperative cardiac catheterisation was carried out in 10 patients including successful balloon angioplasty of the shunt and LPA in one patient. There was a significant improvement in oxygen saturation and a drop in haematocrit level at follow-up. Doppler echocardiography studies in 13 patients revealed functioning shunts in all cases with low velocity continuous flow. Thus BDG is a useful palliative procedure and could be undertaken as the first stage of total cavopulmonary connection in high-risk Fontan groups where biventricular repair is not feasible.

Development of the Chitra tilting disc heart valve prosthesis

BACKGROUND AND AIMS OF THE STUDY

The high prevalence of rheumatic valvular disease in the young population and the high cost of imports necessitated the development of an Indian valve. The development of a tilting disc prosthesis was successfully concluded in February 1995, when the third model completed its clinical trial. The tilting disc valve has an integrally machined cobalt alloy cage, an ultra high molecular weight polyethylene disc and a polyester suture ring. The choice of design was based on its superior hydrodynamics and the age distribution of patients, the majority of whom were below 30 years. The polymer-metal combination was selected for its extremely low wear rate and proven durability in the human body.

MATERIALS AND METHODS

The hydrodynamic performance was tested under steady and pulsatile flow conditions. The accelerated durability of nine test valves was evaluated at 800-840 cycles/min for over 350 million cycles each. Size 23 mm valves mere implanted in the mitral position of five sheep. In a clinical trial, 306 patients with isolated mitral or aortic valve replacements were followed up for a total of 371 patient years (mean 1.37 years and range 0-4 years).

RESULTS

The hydrodynamic performance was comparable to that of proven clinical models. The accelerated testing indicated lifetimes in excess of 50 years and the animal trials showed the valve to be safe. In the clinical trial, there was no incidence of structural failure or paravalvular leak. The linearized rate of late thromboembolism was 6.2%/patient-year (pty), anticoagulant related hemorrhage 0.54%/pty and infective endocarditis 0.54%/pty. At two years, the total actuarial survival was 89.5%. The higher incidence of thromboembolism and the very low incidence of anticoagulant related hemorrhage illustrate the difficulty in the management of anticoagulant therapy in a developing country, while the low incidence of endocarditis reflects their greater resistance to infection.

CONCLUSION

These data clearly showed the valve to be safe and comparable to other similar valves in clinical use.

Open heart surgery in presence of hereditary spherocytosis

A patient with ostium secundum atrial septal defect was operated upon despite having hereditary spherocytosis, without any hemolytic effects of cardiopulmonary bypass. A short bypass time is safe in presence of this congenital hemolytic anemia.

Identification of positive and negative transcriptional regulatory elements of the rabbit angiotensin-converting enzyme gene

The two tissue-specific mRNAs encoding the isozymes of rabbit angiotensin-converting enzyme (ACE) are generated from the same gene by alternative choice of two transcription initiation sites 5.7 kb apart. In the current study, we have characterized the regulatory sites controlling the transcription of the larger pulmonary isozyme mRNA. For this purpose, reporter genes driven by varying lengths of upstream region of the ACE gene were transfected into ACE-producing cells. Our results demonstrated that the transcription of this gene is primarily driven by positive elements within the first 274 bp DNA upstream of the transcription initiation site. The reporter gene driven by this region was expressed in two ACE-producing cells but not in two ACE-non-producing cells thereby establishing its tissue specificity. Our experiments also revealed the existence of a strong negative element located between -692 and -610 positions. This element suppressed the expression of the reporter gene in a dose-dependent and position and orientation-independent fashion thus suggesting that it is a true silencer element. It could also repress the expression of a reporter gene driven by the heterologous strong promoter of the beta-actin gene. The repressing effects of the negative element could be partially overcome by cotransfecting the isolated negative element along with the reporter gene containing the negative element. This result was possibly due to the functional removal of a limiting trans-acting factor which binds to this element. Electrophoretic mobility shift assays revealed that the negative element can form several complexes with proteins present in the nuclear extract of an ACE-producing cell line. At least part of the negative element is strongly conserved in the upstream regions of the human and mouse ACE genes.

Recovery from paraplegia following aortic saddle embolism. Case report

An aortic saddle embolus causing paraplegia is rare and even rarer is a documentation of neurological recovery from this event. A 47 year old male presented with absent pulsations in the lower limbs and paraplegia, both of sudden onset. He underwent immediate bilateral transfemoral embolectomy. The postoperative period was stormy. The paraplegia recovered over a period of 2 months and he could walk to his place of work after 6 months. The rare combination of saddle embolus and paraplegia is discussed. An attempt has been made to verify the hypothesis of Dickson et al which states that a low origin of the great radicular artery (GRA) below T12 level may be responsible for paraplegia when obstructed by a saddle embolus. We found the GRA arising at L2 vertebral level in this patient. Postoperative selective spinal arteriogram and magnetic resonance imaging (MRI) of the spinal cord showed a patent GRA and normal spinal cord structure respectively. Early surgical intervention in restoring the blood flow into the GRA may prevent severe histological changes hitherto responsible for nonrecovery from paraplegia in the earlier reports.

Intracerebral polyposis. Case report

A 25-year-old man presented with nontraumatic cerebrospinal fluid rhinorrhea and meningitis. On investigation, he was found to have a multiloculated intracerebral cystic lesion of the right frontal lobe with a bony lesion inside the cyst, just above the right cribriform plate. Surgery revealed multiple grape-like cystic pedunculated lesions with narrow stalks attached to a bony outgrowth which was adherent to the right cribriform plate. Macroscopically and microscopically, the excised lesions were similar to nasal polyps.

Use of alternative polyadenylation sites for tissue-specific transcription of two angiotensin-converting enzyme mRNAs

The pulmonary isozyme of rabbit angiotensin-converting enzyme (ACE) is encoded by an mRNA of about 5 kb. cDNA clones corresponding to different parts of this mRNA have been isolated and the complete nucleotide sequences of both the coding and non-coding regions of the mRNA have been determined. The encoded protein has 1309 residues with a 33 amino acids-long signal peptide at the amino terminus and a potential membrane-anchoring domain near the carboxyl terminus. There is a strong sequence homology between two regions of the rabbit cDNA and between the rabbit, human, and mouse cDNAs. Comparison of the nucleotide sequences of the 3' untranslated regions of rabbit pulmonary and testicular ACE cDNAs revealed that the testicular cDNA is nested within the pulmonary cDNA at the 3' end. A rabbit genomic clone encompassing this region was isolated and partially sequenced. It was shown that the gene contains two potential polyadenylation sites 628 bp apart within one exon. Northern analyses with an appropriate oligonucleotide probe confirmed that the proximal polyadenylation site is used exclusively for terminating the testicular mRNA whereas the distal one is used exclusively for the pulmonary mRNA. These results demonstrated that the transcription of the two mRNAs encoding the two ACE isozymes not only initiates at two alternative tissue-specific sites which are 5.7 kb apart but the mRNAs also get polyadenylated at two alternative sites which are 628 bp apart.

The mRNAs encoding the two angiotensin-converting isozymes are transcribed from the same gene by a tissue-specific choice of alternative transcription initiation sites

The two tissue-specific isozymes of angiotensin-converting enzyme are encoded by two mRNAs. The 5-kilobase pulmonary mRNA (mRNAP) and the 2.5-kilobase testicular mRNA (mRNAT) have identical sequences near their 3'-ends, whereas each has a unique sequence toward its 5'-end. Here we report that the two mRNAs originate from the same gene by initiation of transcription at two alternative sites. We have isolated a rabbit genomic clone which encodes these mRNAs. The sequence organization of the genome is such that the unique sequence of mRNAP precedes that of mRNAT, which in turn precedes the sequence common to both species. For generation of mRNAP, the mRNAT-specific sequence is eliminated as an intron from the primary transcript by splicing. Transcription of mRNAT, on the other hand, initiates within this intron at the middle of the gene. The exact initiation sites of mRNAT and mRNAP have been determined by DNA sequencing; DNA, oligonucleotide, and antisense RNA protection assays; and primer extension assays. Analyses of the sequence upstream of the transcription initiation sites revealed the presence of putative binding sites of several known transcription factors including SP-1, AP-2, and IID.

Structure of testicular angiotensin-converting enzyme. A segmental mosaic isozyme

The complete amino acid sequence of rabbit testicular angiotensin-converting enzyme has been deduced from the sequence of the corresponding cDNA clone. A protein of the expected molecular weight of 84,000 was translated in vitro from the mRNA encoded by this cDNA. All of the previously determined sequences of seven tryptic peptides from the enzyme are present in the deduced sequence, thus confirming the identity of the protein. From the deduced sequence it appears that the protein contains a signal peptide at the amino terminus and a hydrophobic anchoring domain near the carboxyl terminus. Northern analysis with oligonucleotide probes, whose sequences represented different regions of the cDNA, revealed not only the regions of extensive homology between the mRNAs encoding the testicular and the pulmonary isozymes but also a stretch of sequence near the 5' end unique to the testicular mRNA.