Chitosan/Poly (vinyl alcohol) Based Hydrogels for Biomedical Applications: A Review

The present review aims to give a closer look of hydrogels based on chitosan and poly (vinyl alcohol) and to discuss their potential biomedical applications in drug delivery system. Various investigations based on chitosan/poly (vinyl alcohol) carried out recently by researchers have been reported in this review. Moreover different chemical and physical crosslinking methods used for hydrogels formulations have been summarized and discussed in this overview. Different characterization tools including Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), thermo gravimetric analysis (TGA), differential scanning calorimetry (DSC) and rheological analysis used by researchers have also been reported in this review. Keywords: Hydrogels, Chitosan, Poly (vinyl alcohol), Physical crosslinking, Chemical crosslinkin

Genetic Improvement of Chickpea through Induced Mutation

Following seed treatment by two mutagens (HZ and MMS), four chickpea mutant lines were evaluated to find out selection response in M3 generation. Estimates of variability for yield and yield components were recorded higher. In comparison with the control plants, nitrate reductase activity (NRA) in leaf tissues of all the mutant lines was increased. The early maturity mutant lines showed the highest seed protein content and NRA

Identification and characterisation of quantitative trait loci linked with tolerance to saline-alkaline stress at germination stage in indica rice (oryza sativa l)

As the direct seeding of rice is getting popular, the farmers have shifted from traditional transplantation method to direct seeding method. The problem with this method however is the direct exposure of seeds to abiotic stresses that affect crop establishment. Studies have not been conducted so far to improve the germination tolerance in saline-alkaline conditions. Therefore, the present study was conducted to perform the genomic analysis of tolerance to saline-alkaline stress at germination stage in rice. Parental varieties Pokkali and Pak Basmati were selected out of six rice varieties on the basis of their performance in saline-alkaline conditions. A mapping population was constructed using Pokkali as tolerant and Pak Basmati as sensitive parent. Germination parameters such as final germination percentage, germination value, germination energy, germination velocity, speed of germination, peak value, germination capacity, germination index and mean germination time while growth parameters like germination vigour index, shoot length, root length and total dry biomass were recorded. Parental varieties were optimised for salinealkaline stress limits. Phenotyping of F3 progenies was conducted with the saline alkaline limits optimised in parental varieties. Correlation studies show that germination and growth parameters are positively correlated. It was also found that growth parameters were affected more than germination parameters. The genotypic data of 129 F2 plants for 84 polymorphic markers was used to construct molecular linkage map, with an average interval size of 7.63cM with four gaps of = 40cM and the total length of 3435.5cM. Quantitative Trait Loci Cartographer was used for genomic analysis using three mapping techniques i.e. simple interval mapping, composite interval mapping and multiple interval mapping. Thirty-three QTLs - 17 major and 16 minor were identified using SIM. Forty QTLs (14 major and 26 minor) were identified by CIM. Sixty QTLs were identified using MIM technique. The parental varieties used in this study are potential candidates for abiotic stress studies. These findings would be beneficial in rice breeding programs to develop tolerant cultivars for the saline-alkaline environment through marker assisted selectio

Diff erential genotypic response of two varieties of Hordeum vulgare L. in response to hydrazine hydrate alone and in combination with dimethyl sulfoxide

Induced mutation has been an important tool for a man in bringing desirable changes in plants since times immemorial. Cereals form an integral part of human diet along with pulses, especially in India. Cereals contain a high percentage of carbohydrates along with the considerable amount of proteins. The present experiment was carried out to induce the variability in Hordeum vulgare L. variety RD-2035 and BH-393. The mutagen used in this experiment was hydrazine hydrate (Hz). The mutagen was used singly and in combination with dimethyl sulfoxide (DMSO). Usually, the DMSO is considered as a carrier for a mutagen to enhance the mutagenic activity of that particular mutagen used in combination. The two varieties of seeds were treated with individual concentrations of Hz along with combination treatments with DMSO. The seeds were sown to raise the M1 generation. Cytology of both control and treated plants was observed in the M1 generation. The control plants showed normal meiosis, whereas the treated plants showed different chromosomal abnormalities. The different chromosomal abnormalities were laggard, bridge, micronucleus, and univalents. The meiotic abnormalities were low at lower concentrations of both individual and combination treatments while as the percentage abnormalities increased with increasing concentrations of both individual and combination treatments. M1 seeds were sown to raise the M2 generation. Quantitative characters of both control and treated plants were observed. The lower concentrations of both individual and combination treatments induced desirable changes in quantitative characters while as the higher ones induced negative effects

Ethnobotanical Resources of Manikhel Forests, Orakzai Tirah, Pakistan

Manikhel forests, the far southern extension of Hindu Kush Mountain ranges, exhibit rich floral diversity in its nearly 175 Km2 area. It comprises sub-tropical semi deciduous thorny forests in the southern low lying Mediterranean type of climate and evergreen Oak-Yew forests in the northern faces of the Himalayan type of climate. A wide variety of plants are present in the area but this paper includes only those species whose common use is either known locally or they are in daily use for various purposes. The present investigations comprise 172 plant species belonging to 80 families. Bulk of these plants exhibit multiple uses. The local population is entirely rural and poor. They are primarily dependent on the forest resources for their necessities

Identification and characterisation of quantitative trait loci linked with tolenrance to saline-alkaline stress at germination stage in indica rice (oryza sativa L.)

As the direct seeding of rice is getting popular, the farmers have shifted from traditional transplantation method to direct seeding method. The problem with this method however is the direct exposure of seeds to abiotic stresses that affect crop establishment. Studies have not been conducted so far to improve the germination tolerance in saline-alkaline conditions. Therefore, the present study was conducted to perform the genomic analysis of tolerance to saline-alkaline stress at germination stage in rice. Parental varieties Pokkali and Pak Basmati were selected out of six rice varieties on the basis of their performance in saline-alkaline conditions. A mapping population (F2:3) was constructed using Pokkali as tolerant and Pak Basmati as sensitive parent. Germination parameters such as final germination percentage (FGP), germination value (GV), germination energy (GE), germination velocity (GVe), speed of germination (SG), peak value (PV), germination capacity (GC), germination index (GI) and mean germination time (MGT) while growth parameters like germination vigour index (GVI), shoot length (SL), root length (RL) and total dry biomass (DBM) were recorded. Parental varieties were optimised for salinealkaline stress limits. Phenotyping of F3 progenies was conducted with the salinealkaline limits (pH8/15 dS.m-1) optimised in parental varieties. Correlation studies show that germination and growth parameters are positively correlated. It was also found that growth parameters were affected more than germination parameters. The genotypic data of 129 F2 plants for 84 polymorphic markers was used to construct molecular linkage map, with an average interval size of 7.63cM with four gaps of ≤ 40cM and the total length of 3435.5cM. Quantitative Trait Loci (QTL) Cartographer was used for genomic analysis using three mapping techniques i.e. simple interval mapping (SIM), composite interval mapping (CIM) and multiple interval mapping (MIM). Thirty-three QTLs (17 major and 16 minor) were identified using SIM. Forty QTLs (14 major and 26 minor) were identified by CIM. Sixty QTLs were identified using MIM technique. The parental varieties used in this study are potential candidates for abiotic stress studies. These findings would be beneficial in rice breeding programs to develop tolerant cultivars for the saline-alkaline environment through marker assisted selection

Breast reconstruction at The Aga Khan University - a 10 year audit

Abstract Considering the high incidence of breast cancer and the subsequent need for a mastectomy, the number of patients having breastreconstruction remains relatively low the world over. Most studies from the west show that anywhere between 5% to around 50% of women proceed to reconstruction following a complete mastectomy. There is a great paucity of literature on the subject in Pakistan. Anecdotal and unofficial accounts would suggest that less than a fraction of 1% of women in Pakistan undergo reconstruction following a mastectomy.We reviewed our cases retrospectively over a 10 year study period from January 2005 to December 2014 with the objective to assess our results and to learn from them as well as to attempt to raise the profile of this important reconstructive manoeuver. Our numbers are low when compared internationally. However on a national level it would seem that the numbers currently exceed most institutions in the country. The overall results appear to be acceptable though the low numbers preclude definitive conclusions

Development of markers and crop improvement programmes

            The development of markers for genetic analysis of different plant species, for monitoring the variations in and among species, to create new source of genetic variations by introducing new and favorable traits from landraces and related species, to develop the evolutionary tree among plant species and more importantly to increase the production of crops is painstaking efforts of plant breeders started from initial years of last century. Improvement in marker detecting systems and in the techniques used to identify markers linked to useful traits -Marker assisted selection (MAS) and Quantitative trait loci (QTL) - has enabled great advancements in recent years and can be utilized for more advanced research in future. Identification of markers linked to useful traits is based on complete linkage maps which helped to understand the basics of epistasis, pleiotropy and heterosis. . While morphological markers have been the basics of most work in marker development system but presently the molecular markers like RFLP (restriction fragment length polymorphism), RAPD (random amplified polymorphic DNA), and AFLP (amplified fragment length polymorphism) has generated the valuable marker systems. SNP (single nucleotide polymorphism) and SSR (simple sequence repeat) marker systems have been developed and is predicted to lead advance study by their implementation in breeding programmes. In this review emphasis has been laid on the current stage of marker development and to reveal the potential uses of supplementing the molecular and biochemical marker systems with morphological markers

A Short Review on the Development of Salt Tolerant Cultivars in Rice

Rice is staple food for half of the world. With a population of almost 9.6 billion by the year 2050, there is a dire need of developing techniques to improve the crop plants, not only in terms of better yield but also to withstand harsh environmental conditions and stresses like drought, temperature, flood and salinity. Salinity is second to drought stress and hence it is very important to develop crops tolerant to salinity stress. This review discusses the mechanisms of salt tolerance and the recent developments in understanding the complex tolerance phenomena. One way to address the salinity issue is to develop tolerant rice varieties using conventional and modern breeding techniques for which screening the rice germplasm for the varieties with desired traits is critical. Conventional methods to develop tolerant rice varieties are discussed along with modern biotechnology techniques are also discussed. Quantitative Trait Loci (QTL) and Marker Assisted Selection (MAS) are promising techniques. In addition to these modern techniques, some recent developments in the fields of transgenic plants, haploid breeding and Somaclonal variations have also been discussed. The limited knowledge about molecular and genetic mechanisms to tolerate abiotic stresses, however is a barrier to efficiently develop tolerant cultivars. A combination of conventional and modern biotechnology techniques could possibly open up the new ways