858 research outputs found
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
Asymptotic properties for Volterra integro-dynamic systems
Using the resolvent matrix, a comparison principle and a useful equivalent system, we investigate the asymptotic behavior of linear Volterra integro-dynamic systems on time scales
Distribution and turnover of Langerhans cells during delayed immune responses in human skin
The changes in distribution and turnover of T6+ Langerhans cells (LC) in the skin during delayed immune responses to tuberculin, and in the lesions of tuberculoid leprosy and cutaneous Leishmaniasis were investigated. In each situation, there was a dermal accumulation of monocytes and T cells and epidermal thickening with keratinocyte Ia expression. In the tuberculin response a dramatic change in the distribution of LC was observed. By 41 h, T6+ LC were displaced to the upper zone of the thickening epidermis followed by an almost complete loss of LC from the epidermis by approximately 72 h. After 7 d, T6+ cells started to reappear in the epidermis, which regained almost normal numbers of T6+ LC by 14 d. After antigen administration and initiation of the delayed immune response, enhanced numbers of T6+ cells appeared in association with the mononuclear cell infiltrate of the upper dermal lesions. Their numbers peaked by 72 h, were reduced at 7 d, and again enhanced by 14 d, when the epidermis was being repopulated. Similar numbers of T6+ cells were found in the chronic lesions of tuberculoid leprosy and cutaneous Leishmaniasis but not lepromatous leprosy. The cells of the dermis were identified as typical LC by the presence of Birbeck granules and surface T6 antigen at the electron microscope level. These cells were closely associated with lymphocytes. We have quantified the number of LC, evaluated their directional flux into the epidermis and dermis, determined nearest neighbors, and made predictions as to their fate
Cryosectioning Method for Microdissection of Murine Colonic Mucosa.
The colonic mucosal tissue provides a vital barrier to luminal antigens. This barrier is composed of a monolayer of simple columnar epithelial cells. The colonic epithelium is dynamically turned over and epithelial cells are generated in the stem cell containing crypts of Lieberkuhn. Progenitor cells produced in the crypt-bases migrate toward the luminal surface, undergoing a process of cellular differentiation before being shed into the gut lumen. In order to study these processes at the molecular level, we have developed a simple method for the microdissection of two spatially distinct regions of the colonic mucosa; the proliferative crypt zone, and the differentiated surface epithelial cells. Our objective is to isolate specific crypt and surface epithelial cell populations from mouse colonic mucosa for the isolation of RNA and protein
Comparison of ultrasonographically measured fetal interventricular septal thickness between diabetic and healthy mother
Background: During pregnancy, metabolic changes occur in response to increased nutrient needs of the fetus and mother, including progressive insulin resistance that can lead to gestational diabetes mellitus (GDM). GDM can result in fetal complications. This study aimed to compare fetal interventricular septal thickness, measured by ultrasound, between diabetic and healthy mothers.
Methods: This cross-sectional study was conducted at the department of radiology and imaging, BIRDEM, Dhaka, Bangladesh. A total of 334 subjects were enrolled in this study as per inclusion criteria. The study duration was 2 years; from July 2012 to June 2014. All study subjects were divided into 3 groups named group A, group B, and group C. 167 non-diabetic, 84 controlled diabetics, and 83 uncontrolled diabetic mothers were considered as group A, group B, and group C respectively. Data were analyzed by SPSS computed program.
Results: In this study, 47.9% of subjects in group A were ≤25 years old, while 52.4% of group B and 53.0% of group C were in the 26-30 age range. The mean age was 25.9±3 years in group A, 25.5±2.9 years in group B, and 25.2+3.3 years in group C, with no statistically significant difference between the three groups (p>0.05). The mean gestational age was similar across the three groups, with no statistically significant difference (p>0.05). However, the mean fetal interventricular septal thickness was significantly different between the groups, with group A and B having similar thicknesses, while group C had a significantly larger thickness (p<0.05). The difference in fetal interventricular septal thickness was also statistically significant between the three groups at 32 weeks of gestational age (p<0.05).
Conclusions: In this study, the fetal interventricular septal thickness was significantly higher in uncontrolled diabetic mothers followed by controlled diabetic and non-diabetic and almost alike between non-diabetic and controlled diabetic mothers. The study also revealed that M-mode ultra-sonogram measurement of interventricular septal thickness can be included in routine scanning during the third trimester
Evaluation of polystyrene petri dish-based method for assessing biofilm formation in vitro by Trichosporon spp. and its comparison with test-tube method
Background: Microorganisms growing in a biofilm are associated with chronic and recurrent human infections and are highlyresistant to antimicrobial agents. There are various methods to detect biofilm production such as tube method (TM) and tissueculture plate method followed by microscopic examination by inverted microscope. Objective: This study was conducted tocompare two methods for the detection of biofilms. Methods: In this study, biofilm formation of ten isolates of Trichosporonspp. by test TM (TTM) and polystyrene petri dish method (PDM) was compared. Results: In the TTM, they were weak biofilmproducers as compared to PDM where they were strong biofilms producers. Conclusion: PDM can be safely used to find outpattern of biofilm formation by Trichosporon
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