Correction to Estimation of Gas Holdup Using the Gassed to Ungassed Power Ratio of an Oxygen-Water System in a Stirred and Sparged Tank Contactor

[This corrects the article DOI: 10.1021/acsomega.0c02292.].

Estimation of Gas Holdup Using the Gassed to Ungassed Power Ratio of an Oxygen-Water System in a Stirred and Sparged Tank Contactor

Gas holdup (ε_g) and power correlations in gas-liquid (G-L) systems, apart from the physicochemical properties of the liquid phase, are dependent on impeller-sparger-vessel geometry. To date, reported correlations do not specifically address this issue, and it must be investigated with a unified approach. Here, we propose a correlation via the use of a normalized ε_g that involves the impeller-sparger system geometry for a vessel of standard geometry expressed as a function of an easily measurable and independent operational parameter, that is, (1 - P _g/P _l), where P _g/P _l is the gassed to ungassed power ratio. Furthermore, our work demonstrates that P _g/P _l can be used as a tool for the identification of hydrodynamic regimes. Radial and axial impellers with ring spargers were used in a stirred and sparged contactor (SSTC) of 0.25 m diameter containing 1 × 10^-2 m³ water. The oxygen flowrate (Q _g) was varied from 2.5 to 40 LPM or (4.17 to 66.7) × 10^-5 m³ s^-1, and the agitation intensity (N ₀) was varied from 1.67 to 50 rps at the temperature (θ) = 313 K under atmospheric pressure. This novel correlation is easy to use, offers reasonable precision, and can serve as a valuable alternative to more complex correlation models.

Enhancing gene editing specificity by attenuating DNA cleavage kinetics

Engineered nucleases have gained broad appeal for their ability to mediate highly efficient genome editing. However the specificity of these reagents remains a concern, especially for therapeutic applications, given the potential mutagenic consequences of off-target cleavage. Here we have developed an approach for improving the specificity of zinc finger nucleases (ZFNs) that engineers the FokI catalytic domain with the aim of slowing cleavage, which should selectively reduce activity at low-affinity off-target sites. For three ZFN pairs, we engineered single-residue substitutions in the FokI domain that preserved full on-target activity but showed a reduction in off-target indels of up to 3,000-fold. By combining this approach with substitutions that reduced the affinity of zinc fingers, we developed ZFNs specific for the TRAC locus that mediated 98% knockout in T cells with no detectable off-target activity at an assay background of ~0.01%. We anticipate that this approach, and the FokI variants we report, will enable routine generation of nucleases for gene editing with no detectable off-target activity.

m6A enhances the phase separation potential of mRNA

N⁶-methyladenosine (m⁶A) is the most prevalent modified nucleotide in mRNA^1,2, with ~25% of mRNAs containing at least one m⁶A. Methylation of mRNA to form m⁶A is required for diverse cellular and physiological processes³. Although the presence of m⁶A in an mRNA can affect its fate in different ways, it is unclear how m⁶A directs this process and why the effects of m⁶A can vary in different cellular contexts. Here we show that the cytosolic m⁶A-binding proteins, YTHDF1–3, undergo liquid-liquid phase separation (LLPS) in vitro and in cells. This LLPS is markedly enhanced by mRNAs that contain multiple, but not single, m⁶A residues. Polymethylated mRNAs act as a multivalent scaffold for binding YTHDF proteins, juxtaposing their low-complexity domains, leading to phase separation. The resulting mRNA-YTHDF complexes then partition into different endogenous phase-separated compartments, such as P-bodies, stress granules, or neuronal RNA granules. m⁶A-mRNA is subject to compartment-specific regulation, including reduced mRNA stability and translation. These studies reveal that the number and distribution of m⁶A sites in cellular mRNAs can regulate and influence the composition of the phase-separated transcriptome. Additionally, these findings indicate that the cellular properties of m⁶A-modified mRNAs are governed by liquid-liquid phase separation principles.

Diversifying the structure of zinc finger nucleases for high-precision genome editing

Genome editing for therapeutic applications often requires cleavage within a narrow sequence window. Here, to enable such high-precision targeting with zinc-finger nucleases (ZFNs), we have developed an expanded set of architectures that collectively increase the configurational options available for design by a factor of 64. These new architectures feature the functional attachment of the FokI cleavage domain to the amino terminus of one or both zinc-finger proteins (ZFPs) in the ZFN dimer, as well as the option to skip bases between the target triplets of otherwise adjacent fingers in each zinc-finger array. Using our new architectures, we demonstrate targeting of an arbitrarily chosen 28 bp genomic locus at a density that approaches 1.0 (i.e., efficient ZFNs available for targeting almost every base step). We show that these new architectures may be used for targeting three loci of therapeutic significance with a high degree of precision, efficiency, and specificity.

Reading m6A in the Transcriptome: m6A-Binding Proteins

N⁶-Methyladenosine (m⁶A) is the most prevalent post-transcriptional modification of eukaryotic mRNA and long noncoding RNA. m⁶A mediates its effects primarily by recruiting proteins, including the multiprotein eukaryotic initiation factor 3 complex and a set of proteins that contain the YTH domain. Here we describe the mechanisms by which YTH domain-containing proteins bind m⁶A and influence the fate of m⁶A-containing RNA in mammalian cells. We discuss the diverse, and occasionally contradictory, functions ascribed to these proteins and the emerging concepts that are influencing our understanding of these proteins and their effects on the epitranscriptome.

The m6A pathway facilitates sex determination in Drosophila

The conserved modification N⁶-methyladenosine (m⁶A) modulates mRNA processing and activity. Here, we establish the Drosophila system to study the m⁶A pathway. We first apply miCLIP to map m⁶A across embryogenesis, characterize its m⁶A ‘writer’ complex, validate its YTH ‘readers’ CG6422 and YT521-B, and generate mutants in five m⁶A factors. While m⁶A factors with additional roles in splicing are lethal, m⁶A-specific mutants are viable but present certain developmental and behavioural defects. Notably, m⁶A facilitates the master female determinant Sxl, since multiple m⁶A components enhance female lethality in Sxl sensitized backgrounds. The m⁶A pathway regulates Sxl processing directly, since miCLIP data reveal Sxl as a major intronic m⁶A target, and female-specific Sxl splicing is compromised in multiple m⁶A pathway mutants. YT521-B is a dominant m⁶A effector for Sxl regulation, and YT521-B overexpression can induce female-specific Sxl splicing. Overall, our transcriptomic and genetic toolkit reveals in vivo biologic function for the Drosophila m⁶A pathway.

N⁶-methyladenosine (m⁶A) is a conserved RNA modification that has recently emerged as an important regulator of messenger RNA processing and activity. Here, the authors provide evidence that m6A pathway facilitates female-specific splicing of Sxl, regulating sex determination in Drosophila.

Trend of human brucellosis over a decade at tertiary care centre in North Karnataka

BACKGROUND

Brucellosis is an important zoonotic disease. India having a major agrarian population is expected to have a higher prevalence. However, due to lack of laboratory facility or awareness among clinicians, the disease is largely underreported. The aim of this study was to know the prevalence and trend of human brucellosis over a decade, in patients attending a teaching hospital in North Karnataka, and to understand their geographical distribution.

MATERIALS AND METHODS

The study was conducted from January 2006 to December 2015 at a tertiary care teaching hospital in North Karnataka. A total of 3610 serum samples were evaluated from suspected cases of brucellosis. All serum samples were initially screened by Rose Bengal plate test, and positive samples were further analysed by Serum agglutination test (SAT) using standard Brucella abortus antigen from Indian Veterinary Research Institute, Izatnagar, Uttar Pradesh, India. A titre above or equal to 1:80 IU/ml was considered as positive. Demographic data such as age, sex and native place of these patients were also analysed.

RESULTS

We observed that human brucellosis is present in North Karnataka. The overall seropositivity of brucellosis in suspected cases was 5.1%. The positive titres ranged from 1:80 to 163,840 IU/ml. The majority of the patients were from Gadag, Koppal and Haveri districts of North Karnataka.

CONCLUSION

Our study confirms the presence of human brucellosis in the northern part of Karnataka. Further studies to understand the prevalence of animal brucellosis in these areas will help in implementing prevention measures.

Reversible methylation of m6Am in the 5' cap controls mRNA stability

Internal bases in mRNA can be subjected to modifications that influence the fate of mRNA in cells. One of the most prevalent modified bases is found at the 5' end of mRNA, at the first encoded nucleotide adjacent to the 7-methylguanosine cap. Here we show that this nucleotide, N6,2'-O-dimethyladenosine (m6Am), is a reversible modification that influences cellular mRNA fate. Using a transcriptome-wide map of m6Am we find that m6Am-initiated transcripts are markedly more stable than mRNAs that begin with other nucleotides. We show that the enhanced stability of m6Am-initiated transcripts is due to resistance to the mRNA-decapping enzyme DCP2. Moreover, we find that m6Am is selectively demethylated by fat mass and obesity-associated protein (FTO). FTO preferentially demethylates m6Am rather than N6-methyladenosine (m6A), and reduces the stability of m6Am mRNAs. Together, these findings show that the methylation status of m6Am in the 5' cap is a dynamic and reversible epitranscriptomic modification that determines mRNA stability.

m(6)A RNA methylation promotes XIST-mediated transcriptional repression

The long non-coding RNA X-inactive specific transcript (XIST) mediates the transcriptional silencing of genes on the X chromosome. Here we show that, in human cells, XIST is highly methylated with at least 78 N⁶-methyladenosine (m⁶A) residues-a reversible base modification of unknown function in long non-coding RNAs. We show that m⁶A formation in XIST, as well as in cellular mRNAs, is mediated by RNA-binding motif protein 15 (RBM15) and its paralogue RBM15B, which bind the m⁶A-methylation complex and recruit it to specific sites in RNA. This results in the methylation of adenosine nucleotides in adjacent m⁶A consensus motifs. Furthermore, we show that knockdown of RBM15 and RBM15B, or knockdown of methyltransferase like 3 (METTL3), an m⁶A methyltransferase, impairs XIST-mediated gene silencing. A systematic comparison of m⁶A-binding proteins shows that YTH domain containing 1 (YTHDC1) preferentially recognizes m⁶A residues on XIST and is required for XIST function. Additionally, artificial tethering of YTHDC1 to XIST rescues XIST-mediated silencing upon loss of m⁶A. These data reveal a pathway of m⁶A formation and recognition required for XIST-mediated transcriptional repression.

5' UTR m(6)A Promotes Cap-Independent Translation

Protein translation typically begins with the recruitment of the 43S ribosomal complex to the 5' cap of mRNAs by a cap-binding complex. However, some transcripts are translated in a cap-independent manner through poorly understood mechanisms. Here, we show that mRNAs containing N(6)-methyladenosine (m(6)A) in their 5' UTR can be translated in a cap-independent manner. A single 5' UTR m(6)A directly binds eukaryotic initiation factor 3 (eIF3), which is sufficient to recruit the 43S complex to initiate translation in the absence of the cap-binding factor eIF4E. Inhibition of adenosine methylation selectively reduces translation of mRNAs containing 5'UTR m(6)A. Additionally, increased m(6)A levels in the Hsp70 mRNA regulate its cap-independent translation following heat shock. Notably, we find that diverse cellular stresses induce a transcriptome-wide redistribution of m(6)A, resulting in increased numbers of mRNAs with 5' UTR m(6)A. These data show that 5' UTR m(6)A bypasses 5' cap-binding proteins to promote translation under stresses.

Manipulation and assessment of gut microbiome for metabolic studies

The mammalian gut is inhabited by a complex and highly diverse population of bacteria. About 100 trillion microbes are present in the human gut, a number ten times more than the total number of cells in an adult human body. These microorganisms play an important role in several fundamental and crucial processes such as immunity, digestion, synthesis of vitamins, and metabolizing bile acids, sterols, and xenobiotics in the host, thereby influencing human health. Identification and manipulation of these metabolic interfaces is therefore critical. Here, we present a set of methods for manipulation and targeting the 16S rRNA based identification of rodent gut microbiota using Sanger's and next-generation sequencing platforms. Novel methods for manipulation of gut microbiota are also presented. In principle, these methods can be easily adapted to most rodent models for successful screening and manipulation of gut microbiome, to generate a better understanding of their role in metabolic disease.

Transcriptome analysis of Anopheles stephensi embryo using expressed sequence tags

Germ band retraction (GBR) stage is one of the important stages during insect development. It is associated with an extensive epithelial morphogenesis and may also be pivotal in generation of morphological diversity in insects. Despite its importance, only a handful of studies report the transcriptome repertoire of this stage in insects. Here, we report generation, annotation and analysis of ESTs from the embryonic stage (16-22 h post fertilization) of laboratoryreared Anopheles stephensi mosquitoes. A total of 1002 contigs were obtained upon clustering of 1140 high-quality ESTs, which demonstrates an astonishingly low transcript redundancy (12.1 percent). Putative functions were assigned only to 213 contigs (21 percent), comprising mainly of transcripts encoding protein synthesis machinery. Approximately 78 percent of the transcripts remain uncharacterized, illustrating a lack of sequence information about the genes expressed in the embryonic stages of mosquitoes. This study highlights several novel transcripts, which apart from insect development, may significantly contribute to the essential biological complexity underlying insect viability in adverse environments. Nonetheless, the generated sequence information from this work provides a comprehensive resource for genome annotation, microarray development, phylogenetic analysis and other molecular biology applications in entomology.

Human mitochondrial NDUFS3 protein bearing Leigh syndrome mutation is more prone to aggregation than its wild-type

NDUFS3 is an integral subunit of the Q module of the mitochondrial respiratory Complex-I. The combined mutation (T145I + R199W) in the subunit is reported to cause optic atrophy and Leigh syndrome accompanied by severe Complex-I deficiency. In the present study, we have cloned and overexpressed the human NDUFS3 subunit and its double mutant in a soluble form in Escherichia coli. The wild-type (w-t) and mutant proteins were purified to homogeneity through a serial two-step chromatographic purification procedure of anion exchange followed by size exclusion chromatography. The integrity and purity of the purified proteins was confirmed by Western blot analysis and MALDI-TOF/TOF. The conformational transitions of the purified subunits were studied through steady state as well as time resolved fluorescence and CD spectroscopy under various denaturing conditions. The mutant protein showed altered polarity around tryptophan residues, changed quenching parameters and also noticeably altered secondary and tertiary structure compared to the w-t protein. Mutant also exhibited a higher tendency than the w-t protein for aggregation which was examined using fluorescent (Thioflavin-T) and spectroscopic (Congo red) dye binding techniques. The pH stability of the w-t and mutant proteins varied at extreme acidic pH and the molten globule like structure of w-t at pH1 was absent in case of the mutant protein. Both the w-t and mutant proteins showed multi-step thermal and Gdn-HCl induced unfolding. Thus, the results provide insight into the alterations of NDUFS3 protein structure caused by the mutations, affecting the overall integrity of the protein and finally leading to disruption of Complex-I assembly.

Functional genomics of fuzzless-lintless mutant of Gossypium hirsutum L. cv. MCU5 reveal key genes and pathways involved in cotton fibre initiation and elongation

Background

Fuzzless-lintless cotton mutants are considered to be the ideal material to understand the molecular mechanisms involved in fibre cell development. Although there are few reports on transcriptome and proteome analyses in cotton at fibre initiation and elongation stages, there is no comprehensive comparative transcriptome analysis of fibre-bearing and fuzzless-lintless cotton ovules covering fibre initiation to secondary cell wall (SCW) synthesis stages. In the present study, a comparative transcriptome analysis was carried out using G. hirsutum L. cv. MCU5 wild-type (WT) and it’s near isogenic fuzzless-lintless (fl) mutant at fibre initiation (0 dpa/days post anthesis), elongation (5, 10 and 15 dpa) and SCW synthesis (20 dpa) stages.

Results

Scanning electron microscopy study revealed the delay in the initiation of fibre cells and lack of any further development after 2 dpa in the fl mutant. Transcriptome analysis showed major down regulation of transcripts (90%) at fibre initiation and early elongation (5 dpa) stages in the fl mutant. Majority of the down regulated transcripts at fibre initiation stage in the fl mutant represent calcium and phytohormone mediated signal transduction pathways, biosynthesis of auxin and ethylene and stress responsive transcription factors (TFs). Further, transcripts involved in carbohydrate and lipid metabolisms, mitochondrial electron transport system (mETS) and cell wall loosening and elongation were highly down-regulated at fibre elongation stage (5–15 dpa) in the fl mutant. In addition, cellulose synthases and sucrose synthase C were down-regulated at SCW biosynthesis stage (15–20 dpa). Interestingly, some of the transcripts (~50%) involved in phytohormone signalling and stress responsive transcription factors that were up-regulated at fibre initiation stage in the WT were found to be up-regulated at much later stage (15 dpa) in fl mutant.

Conclusions

Comparative transcriptome analysis of WT and its near isogenic fl mutant revealed key genes and pathways involved at various stages of fibre development. Our data implicated the significant role of mitochondria mediated energy metabolism during fibre elongation process. The delayed expression of genes involved in phytohormone signalling and stress responsive TFs in the fl mutant suggests the need for a coordinated expression of regulatory mechanisms in fibre cell initiation and differentiation.

Identification of cytoplasmic capping targets reveals a role for cap homeostasis in translation and mRNA stability

The notion that decapping leads irreversibly to messenger RNA (mRNA) decay was contradicted by the identification of capped transcripts missing portions of their 5' ends and a cytoplasmic complex that can restore the cap on uncapped mRNAs. In this study, we used accumulation of uncapped transcripts in cells inhibited for cytoplasmic capping to identify the targets of this pathway. Inhibition of cytoplasmic capping results in the destabilization of some transcripts and the redistribution of others from polysomes to nontranslating messenger ribonucleoproteins, where they accumulate in an uncapped state. Only a portion of the mRNA transcriptome is affected by cytoplasmic capping, and its targets encode proteins involved in nucleotide binding, RNA and protein localization, and the mitotic cell cycle. The 3' untranslated regions of recapping targets are enriched for AU-rich elements and microRNA binding sites, both of which function in cap-dependent mRNA silencing. These findings identify a cyclical process of decapping and recapping that we term cap homeostasis.

Identification of the human PMR1 mRNA endonuclease as an alternatively processed product of the gene for peroxidasin-like protein

The PMR1 endonuclease was discovered in Xenopus liver and identified as a member of the large and diverse peroxidase gene family. The peroxidase genes arose from multiple duplication and rearrangement events, and their high degree of sequence similarity confounded attempts to identify human PMR1. The functioning of PMR1 in mRNA decay depends on the phosphorylation of a tyrosine in the C-terminal polysome targeting domain by c-Src. The sequences of regions that are required for c-Src binding and phosphorylation of Xenopus PMR1 were used to inform a bioinformatics search that identified two related genes as potential candidates for human PMR1: peroxidasin homolog (PXDN) and peroxidasin homolog-like (PXDNL) protein. Although each of these genes is predicted to encode a large, multidomain membrane-bound peroxidase, alternative splicing of PXDNL pre-mRNA yields a transcript whose predicted product is a 57-kDa protein with 42% sequence identity to Xenopus PMR1. Results presented here confirm the existence of the predicted 57-kDa protein, show this is the only form of PXDNL detected in any of the human cell lines examined, and confirm its identity as human PMR1. Like the Xenopus protein, human PMR1 binds to c-Src, is tyrosine phosphorylated, sediments on polysomes, and catalyzes the selective decay of a PMR1 substrate mRNA. Importantly, the expression of human PMR1 stimulates cell motility in a manner similar to that of the Xenopus PMR1 expressed in human cells, thus providing definitive evidence linking endonuclease decay to the regulation of cell motility.

Surface Engineering of Polycaprolactone by Biomacromolecules and their Blood Compatibility

Improving blood compatibility of biodegradable polymers is an area of intensive research in blood contacting devices. In this study, curdlan sulphate and heparin-modified poly (caprolactone) (PCL) hybrids were developed by physically entrapping these molecules on the PCL surface. This modification technique was performed by reversible gelation of the PCL surface region following exposure to a solvent and nonsolvent mixture. The presence of these biomacromolecules on the PCL surface was verified by atomic force microscopy (AFM) and scanning electron microscopy and energy dispersive X-ray analysis (SEM-EDAX) analysis, while wettability of the films was investigated by dynamic contact angle measurements. The blood compatibilities of the surface-modified films were examined using in vitro platelet and leukocyte adhesion and thrombus formation. Mouse RAW 264.7 macrophage cells were used to assess the cell adhesion and inflammatory response to the modified surface by quantifying mRNA expression levels of proinflammatory cytokines namely TNF-α and IL-1β using real-time polymerase chain reaction (RT-PCR). A lower platelet and leukocyte adhesion and activation was observed on the modified films incubated with whole human blood for 2 h. The thrombus formation on the PCL was significantly decreased upon immobilization of both curdlan sulphate (39%, *p<0.05) and heparin (28%, *p<0.01) when compared to bare PCL (80%). All of these results revealed that improved blood compatibility was obtained by surface entrapment of both curdlan sulphate (CURS) and heparin (HEP) onto PCL films. Both PCL-CURS and PCL-HEP films reduced RAW 264.7 macrophage cell adhesion (*p<0.05) with respect to the base unmodified PCL. The cellular inflammatory response was suppressed on the modified substrates. The mRNA expression levels of proinflammmatory cytokines (TNF-α and IL-1β) were upregulated on bare PCL, while it was significantly lower on PCL-CURS and PCL-HEP substrates (**p<0.001). Thus, this biomacromolecule entrapment process can be applied on PCL in order to achieve improved blood compatibility and reduced inflammatory host response for its future blood contacting applications.

The biocompatibility of sulfobetaine engineered polymethylmethacrylate by surface entrapment technique

Sulfobetaine-modified polymethylmethacrylate (PMMA) systems were created by physically entrapping the zwitterionic species on the PMMA surface. The presence of the sulfobetaine molecules on these surfaces were verified by ATR-FTIR and SEM-EDAX analysis, while wettability of the films was investigated by dynamic contact angle measurements. The short-term (4 h) adhesion of two bacterial species (gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa) on these surfaces were studied. Mouse RAW 264.7 macrophage cells were used to assess the cell adhesion and inflammatory response by quantifying the expression levels of proinflammatory cytokines namely TNFalpha and IL1beta by measuring their mRNA profiles in the cells using real-time polymerase chain reaction (RT-PCR) normalized to the house keeping gene GAPDH. Whilst mouse L-929 fibroblast cells were used to assess the propensity for the materials to support fibroblast cell adhesion. A decrease in the adhesion of S. aureus by 63% and P. aeruginosa by 49% was observed on sulfobetaine modified PMMA films after 4 h. In all the cases, sulfobetaine modified PMMA films reduced cellular adhesion events (*P < 0.05) with respect to the base materials, which could be linked to the reduced protein adsorption observed on these surfaces. The cellular inflammatory response was suppressed on sulfobetaine modified substrates as expression levels of pro-inflammatory cytokines (TNFalpha and IL1beta) was found to be up regulated on bare PMMA, while it was significantly lower on sulfobetaine modified PMMA (**P < 0.001). Thus the sulfobetaine entrapment process can be applied on polymethylmethacrylate in order to achieve low biointeractions and reduced inflammatory host responses for various biomedical and biotechnological applications.

The biocompatibility of sulfobetaine engineered poly (ethylene terephthalate) by surface entrapment technique

Sulfobetaine-modified poly(ethylene terephthalate) (PET) systems were created by physically entrapping the zwitterionic species on the PET surface. The presence of the sulfobetiane molecules on these surfaces were verified by ATR-FTIR and SEM-EDAX analysis, while wettability of the films was investigated by water contact angle measurements. The blood compatibility of the modified films was evaluated by platelet adhesion in human platelet-rich plasma (PRP). The adhesion and inflammatory response of Mouse RAW 264.7 macrophage cells were studied. The surface induced cellular inflammatory response was determined by quantifying the expression levels of proinflammatory cytokines namely TNF-alpha and IL-1beta by measuring their mRNA profiles in the cells using real time polymerase chain reaction normalized to the housekeeping gene GAPDH. L-929 fibroblast cells were used to assess the propensity of the materials to support the fibroblast cell adhesion. A lower platelet adhesion and activation were observed on the sulfobetaine-modified PET film incubated in PRP after 2h when compared to control. The modified film reduced cellular adhesion events ( p<0.05) with respect to the base material, which could be linked to the reduced protein adsorption observed on this surface. The cellular inflammatory response was suppressed on sulfobetaine-modified substrate. Expression levels of pro-inflammmatory cytokines (TNF-alpha and IL-1beta) was found to be upregulated on bare PET, while it was significantly lower on modified PET ( p<0.001). Thus the sulfobetaine entrapment process can be applied on PET in order to achieve low biointeractions and reduced inflammatory host response for various biomedical and biotechnological applications.

Generation, annotation, and analysis of ESTs from midgut tissue of adult female Anopheles stephensi mosquitoes

Background

Malaria is a tropical disease caused by protozoan parasite, Plasmodium, which is transmitted to humans by various species of female anopheline mosquitoes. Anopheles stephensi is one such major malaria vector in urban parts of the Indian subcontinent. Unlike Anopheles gambiae, an African malaria vector, transcriptome of A. stephensi midgut tissue is less explored. We have therefore carried out generation, annotation, and analysis of expressed sequence tags from sugar-fed and Plasmodium yoelii infected blood-fed (post 24 h) adult female A. stephensi midgut tissue.

Results

We obtained 7061 and 8306 ESTs from the sugar-fed and P. yoelii infected mosquito midgut tissue libraries, respectively. ESTs from the combined dataset formed 1319 contigs and 2627 singlets, totaling to 3946 unique transcripts. Putative functions were assigned to 1615 (40.9%) transcripts using BLASTX against UniProtKB database. Amongst unannotated transcripts, we identified 1513 putative novel transcripts and 818 potential untranslated regions (UTRs). Statistical comparison of annotated and unannotated ESTs from the two libraries identified 119 differentially regulated genes. Out of 3946 unique transcripts, only 1387 transcripts were mapped on the A. gambiae genome. These also included 189 novel transcripts, which were mapped to the unannotated regions of the genome. The EST data is available as ESTDB at .

Conclusion

3946 unique transcripts were successfully identified from the adult female A. stephensi midgut tissue. These data can be used for microarray development for better understanding of vector-parasite relationship and to study differences or similarities with other malaria vectors. Mapping of putative novel transcripts from A. stephensi on the A. gambiae genome proved fruitful in identification and annotation of several genes. Failure of some novel transcripts to map on the A. gambiae genome indicates existence of substantial genomic dissimilarities between these two potent malaria vectors.

TecoflexTM functionalization by curdlan and its effect on protein adsorption and bacterial and tissue cell adhesion

Curdlan modified polyurethane was created by physically entrapping the former on TecoflexTM surface. ATR-FT-IR, SEM-EDAX and AFM analysis revealed the formation of stable thin curdlan layer on the film. Contact-angle measurements showed that the modified film was highly hydrophilic. Confocal laser scanning microscopy showed the existence of entrapped layer of approximately 20-25 microm in depth. Surface entrapment of curdlan minimized both protein adsorption and mouse L929 fibroblast cell adhesion relative to the control. Surface induced cellular inflammatory response was determined from the expression levels of proinflammatory cytokine TNF-alpha, by measuring their mRNA profiles in the cells using real time polymerase chain reaction (RT-PCR) normalized to the housekeeping gene GAPDH. The inflammatory response was suppressed on the modified substrate as expression of TNF-alpha mRNA was found to be up regulated on TecoflexTM, while it was significantly lower on curdlan substrate. The adhesion of S. aureus decreased by 62% on curdlan modified surface. Using such simple surface entrapment process, it will be possible to develop well-defined surface modifications that promote specific cell interactions and perhaps better performance in the long-term as implant.

Catheter-less suprapubic cystolithotomy in children

Bladder stones in children are common in developing countries and the procedure of choice for their removal is suprapubic cystolithotomy. It is standard practice to drain the bladder for a few days post-operatively to prevent urinary leakage. We have observed that, if the bladder is closed meticulously in 2 layers, bladder drainage by means of a catheter is not required. We have analysed 86 children treated by suprapubic cystolithotomy without a catheter. Size of the stones and intra-operative findings were noted and it was found that 85% of the patients had an excellent result; 10% had a satisfactory result and 4.7% were unsatisfactory. The advantages of the procedure and selection of the patients are discussed.

Duplication of the pinna (polyotia) in a case of Brachmann-de Lange syndrome

A rare case of polyotia in Brachmann-de Lange syndrome (Goodman and Gorlin, 1977) is presented and a method for the surgical correction of the duplicated auricle briefly outlined. A review of relevant literature is included in the discussion.