STRUCTURAL COMPARISON OF PROKARYOTIC AND EUKARYOTIC FOLATE TRANSPORTERS BY COMPUTATIONAL APPROACH

Objective: In silico approach has particularly drawn attention in providing a realistic representation needed to understand the fundamental molecular structure of a transporter. The importance of folate metabolism and role in the internalization of antifolates in eukaryotes have been studied extensively, but the structural study of folate transporters in Homo sapiens (HFT), Plasmodium falciparum (PFT), and Streptococcus sp. (SFT) is still lacking. This study was conducted to study and compare the structures of prokaryotic and eukaryotic folate transporters. Methods: HFT, PFT, and SFT were queried using blast and sequences were retrieved using National Center for Biotechnology and Information (NCBI) databases. This was superseded by structural and functional prediction of transporters. The structure has been generated using Swiss model which was visualized using PyMol and validated by Procheck and ERRAT analysis along with the values of different secondary structures mapping to diverse sections of the Ramachandran plot. The structural and functional comparison was performed by PROSO, ProFunc, TM Score, Porewalker, TMHMM, and Protscale. Result: All the parameters for structural comparison suggest that H. sapiens folate transporter is 16.67% and 17.72% identical to Plasmodium and Streptococcus whereas Plasmodium is 21.59% identical to Streptococcus. The evaluation of transmembrane helices and hydrophobicity resulted in the presence of 1, 4, and 12 membrane-spanning segments with predicted US, UDUD, and UDS as pore shape in Plasmodium, Streptococcus, and humans. Conclusion: Such folate receptors are the main targets for the specific conveyance of antifolates. The differences found between these species may offer possibilities for the development of new drugs in future.Â

Impact of polymeric additives on the functionality of microfibrillar cellulose

The aim of the work presented in this thesis was to investigate the impact of different mechanical treatments on the structure and physical properties of microfibrillar cellulose (MFC) and examine further changes upon drying of these MFC suspensions. It has been demonstrated that depending on the type of homogeniser and number of passes through the homogeniser results in a different variety of MFC with a distinct degree of fibrillation. An entangled network structure of MFC plays an important role in maintaining the rheological properties as well as water mobility in the system. Spin-spin relaxation time (T2) of the highly entangled microfibrils network indicates that the water mobility was higher in suspensions with a high degree of fibrillation, as compared to the low degree of fibrillation. It is now well established that during the drying stage MFC fibril-aggregates are formed due to strong intermolecular hydrogen bonds within the network structure. Due to a lack of redispersibility in water and the presence of fibril-aggregates, a non-homogenous distribution throughout the system was observed and the aqueous suspension of redispersed MFC shows a noticeable reduction in complex and shear viscosities. Hence, the next stage of the study focused on to stabilise the fibril-networks of microfibrils upon the drying, where the impact of different polymeric additives i.e. carboxyl methylcellulose (CMC), locust bean gum (LBG) and a blend of CMC/LBG was investigated. The addition of polymeric additives significantly improves the redispersibility of dried MFC in water with reduced fibrils aggregates. The interaction between microfibrils and additives are driven by surface OH-group-mediated hydrogen bonds; however the extents of these interactions are highly dependent on the type of additive used to stabilise the microfibrils. The point of the addition of polymeric additives plays an important role in terms of interaction between the polymeric additive and MFC. Co-processing of MFC and polymeric additives has a noticeable impact on the degree of fibrillation (visualised through light microscopy and degree of transparency) of the final MFC product. The presence of a charged polymeric additive such as carboxyl methyl cellulose (CMC) results in strong synergistic interaction with MFC, whereas weak synergistic interaction is reported with Locust bean gum (LBG). The addition of a CMC/LBG blend also showed strong synergistic interaction with MFC when added in a small amount. The amounts of additive present in the system have a noticeable impact on the viscoelastic properties of the suspensions. At ambient temperature, the MFC/additives suspensions formed a weak gel-like network. It was found that a polymeric additive forms a surface coating on MFC fibrils which protects the fibrils, to form strong intermolecular hydrogen bonds during the drying process, resulting in improved redispersibility of the dry product in an aqueous medium. The interaction between MFC and polymeric additives leads to an increase in moisture uptake even after drying process. Increase in water accessibility within the microfibril network was evident with Dynamic Vapour sorption analysis and low-temperature thermal transitions measured by Differential Scanning Calorimetry. This research also features a preliminary study on the potential application of MFC produced from softwood spruce as a dietary fibre for food application. This includes a comparison between the microstructure and different physical properties of softwood MFC (flakes and powder) with food grade commercial dietary fibres e.g. citrus fibres. Softwood MFC (both flakes and powder form) showed similar rheological properties to other cellulosic dietary fibres such as citrus fibres. Due to a highly entangled network structure softwood MFC showed the highest water retention values (also known as water holding capacity) as compared to other cellulosic fibres. A comparison of the rate of taste i.e. salt perception was also carried out, and the structural features of MFC affect this and appear to be more similar to soluble hydrocolloid solutions than the particulate systems such as citrus fibres. In summary, this thesis describes the mechanistic understanding of the interaction between MFC and different polymeric additives such as CMC and LBG. This research highlights the these interactions results in different microstructures affecting the functional properties of MFC such as redispersing behaviour, water mobility, low-temperature polymer-water interactions and rheological properties. Microfibrillar cellulose (MFC) are not only fundamentally interesting but most importantly they are practical, and certainly offers a more environmentally friendly, and cost-effective ingredient for various traditional commercial applications such as paints, composites and adhesives. This work also proves, for the first time, that the MFC from softwood can also be used as an ingredient for food applications as a bulking agent, stabilising agent, texture and viscosity enhancer

Hormonal effects of drosperinone and ethinyl estradiol based combined oral contraceptives on polycystic ovarian syndrome

Background: Polycystic ovarian syndrome (PCOS) is a common endocrine disorder treated with combined oral contraceptives (COCs). The androgenic potential of any type of COC is in part determined by the progestin present. A newer form of progestin, drospirenone, has been recently introduced, and is available in combination with ethinyl estradiol.Methods: The study was conducted on 60 patients fulfilling inclusion criteria, in the department of obstetrics and gynecology, Terna Medical College and Hospital. Patients were diagnosed as PCOS according to Rotterdam criteria. After initial evaluation, blood samples were sent for levels of serum luteinizing hormone (LH), follicle stimulating hormone (FSH), dehydroepiandrosterone-sulphate (DHEA-S), free testosterone, sex hormone binding globulin (SHBG). Each patient was advised to take a combination of EE (30 mcg) + drosperinone (3 mg), 1 tablet daily from the second day of her menstruation for 21 days then a 7 days gap and again for 21 days and so on cyclically for 3 cycles, then to repeat the tests as done at the beginning.  Hirsutism was assessed clinically using the Ferriman-Gallwey scale at initial visit and three months later.Results: We found a significant improvement in the Serum LH, FSH levels and a significant fall in free testosterone levels accompanied by a rise in SHBG levels. There is also overall improvement in the hirsutism scores.Conclusions: Drosperinone based COCs are a good and effective means of treatment of PCOS. Treatment duration of three months was found to be effective in our study

Effect of moisture content on thermal and water absorption properties of microfibrillar cellulose with polymeric additives

The aim of this study was 1) to investigate the influence of polymeric additives such as carboxyl methyl cellulose (CMC) and locust bean gum (LBG) added before and after homogenisation on the moisture uptake of microfibrillar cellulose (MFC) in the dry and semi-wet state; and 2) to further understand the thermally induced structural transitions of low moisture MFC in the presence of the polymeric additives. A higher moisture content in the highly dense MFC network maintains the fibrillated network structure, which is lost during the drying process resulting in MFC aggregates. The addition of polymeric additives results in the regaining of the structure upon redispersion of the dry material with CMC being more effective than LBG). Results also indicated that CMC has a high level of compatibility with MFC, whereas LBG appears to have limited distribution in the MFC dense microfibrillar network and probably exists as a separate phase when added after homogenisation, however co-processing of LBG and cellulose significantly changed this behaviour. The presence of low-temperature transitions in MFC/additives/water mixtures indicates the involvement of these semi-flexible polymeric additives in the formation of liquid crystals when added to MFC in low moisture environments (2% and 20% w/w). An insight is offered into the theory of surface interactions between MFC and polymeric additives, which prevents the agglomeration of microfibrils present in the highly fibrillated suspension upon drying

A comparison of the sensory and rheological properties of different cellulosic fibres for food

The impact of different cellulosic microstructures formed by highly entangled fibre networks 8 were studied for food applications as dietary fibre. This paper reports the impact of microstructure on the rheological and sensory behaviour of the aqueous suspensions of particulate and fibrillated forms of softwood cellulosic fibres, and were compared with citrus fibre. An aqueous suspension of cellulosic fibres shows stable viscoelastic gel-like behaviour as a function of frequency. The particulate form of cellulosic fibres showed lowest shear viscosity as compared to the entangled network system at comparable concentrations. To provide further insight into the relationship between the structure of cellulosic fibre systems and perception of salt taste in aqueous suspensions of softwood cellulosic fibres (fibrillated and particulate form) and citrus fibres with matched shear viscosities were studied. A hypothesis to explain why softwood cellulosic fibre (CTE) with entangled network structure prolongs the taste perception is presented

Generalized -Type I Univex Functions in Multiobjective Optimization

A new class of generalized functions (---)-type I univex is introduced for a nonsmooth multiobjective programming problem. Based upon these generalized functions, sufficient optimality conditions are established. Weak, strong, converse, and strict converse duality theorems are also derived for Mond-Weir-type multiobjective dual program

Isolation of Halophilic Bacteria and Their Screening for Extracellular Enzyme Production

617-622Halophiles are those microorganisms which are found at high salt concentration. These microorganisms have the capability to form a wide array of bioactive substances that have different applications in various industries. This work focussed at the isolation and screening of various halophilic bacterial strains from different places in Rajasthan and Tamil Nadu. Using a complete medium with different salt concentrations, 70 halophilic bacteria were isolated from 4 different sites. These isolated bacteria were then examined and screened out for the synthesis of different extracellular enzymes, such as cellulase, lipase and amylase. Out of the total, 24 isolates were found positive for amylase, 9 for lipase and 16 for cellulase. These enzymes can perform the hydrolytic activity at high salt concentrations. The various halophilic bacterial strains isolated from various places show a prospective for use in a range of biotechnological and molecular biology experiments and the extremozymes obtained from these bacteria have great industrial importance

Isolation of Halophilic Bacteria and Their Screening for Extracellular Enzyme Production

Halophiles are those microorganisms which are found at high salt concentration. These microorganisms have the capability to form a wide array of bioactive substances that have different applications in various industries. This work focussed at the isolation and screening of various halophilic bacterial strains from different places in Rajasthan and Tamil Nadu. Using a complete medium with different salt concentrations, 70 halophilic bacteria were isolated from 4 different sites. These isolated bacteria were then examined and screened out for the synthesis of different extracellular enzymes, such as cellulase, lipase and amylase. Out of the total, 24 isolates were found positive for amylase, 9 for lipase and 16 for cellulase. These enzymes can perform the hydrolytic activity at high salt concentrations. The various halophilic bacterial strains isolated from various places show a prospective for use in a range of biotechnological and molecular biology experiments and the extremozymes obtained from these bacteria have great industrial importance

The impact of nitrogen gas flushing on the stability of seasonings: volatile compounds and sensory perception of cheese & onion seasoned potato crisps

The impact of natural cheese and onion seasoning on the sensory perception and shelf life stability of potato crisps was studied. This study was carried out to evaluate the impact of nitrogen (N2) gas flushing on the shelf-life stability and sensory attributes of cheese & onion seasoned potato crisps. Markers of lipid oxidation and flavour volatile compounds were evaluated in sliced, unwashed, batch fried potato crisps during accelerated storage at 45 °C for 10 weeks. Volatile flavour compounds were evaluated by headspace gas analysis using solid phase microextraction (SPME) GC-MS and correlated with sensory perception. Gas flushing significantly increases the shelf life of both unsalted and cheese & onion seasoned potato crisps in terms of the stability of volatile compounds and sensory perception. Further to this, the addition of the cheese & onion seasoning increased the shelf life of the base potato crisp; this is proposed to be explained by the antioxidant properties of milk proteins in the seasoning. Sensory evaluation indicated that the key negative sensory attributes reported were rancidity and stale attributes, which were correlated to the progression of lipid oxidation and loss of flavour over storage time irrespective of the packaging environment (with/without gas flushing)