Effect Of Microenvironmental Factors Research Articles

Effects of Micro-Environmental Factors on Students’ Learning in Classroom at College Level in Pakistan

Effects of Micro-Environmental Factors on Students’ Learning in Classroom at College Level in Pakistan

Effects of microenvironmental factors on the diversity and composition of fern and orchid assemblages in an Andean paramo in Peru

Paramos are highly diverse ecosystems of tropical mountains above the tree line, where plant communities are frequently exposed to extreme climatic conditions. In this study, we analyzed the influence of microenvironmental factors (slope, cover of rocks, herbs and shrubs) on the richness, abundance and composition of fern and orchid assemblages in a remote, undisturbed paramo in the Peruvian Andes. We recorded the abundance and the life form (epiphyte, lithophyte, terrestrial) of fern and orchid species in 24 plots. In each plot (10 m × 10 m), we measured the cover of shrubs, herbaceous plants and rocks as well as slope and elevation. In total, we recorded 28 species (1861 individuals) of ferns and 33 species (5067 individuals) of orchids. Approximately 40% of the fern and 36% of the orchid species colonized all three substrates, although the most common life form was terrestrial. The total abundance and richness of ferns increased with shrub cover, whereas the total abundance of orchids decreased with herbaceous cover. Shrub cover also affected the relative abundances of ferns and orchids, depending on species, although no species was restricted to any particular microenvironmental conditions. Our results highlight the importance of shrubs in providing niches for a high fern diversity under the stressful environment of the paramo, while an increasing herbaceous cover appears to outcompete many orchid species. The recorded ferns and orchids contribute substantially to the paramo flora in Peru and included new species documented during this study.

Haematopoiesis in Zebrafish (Danio Rerio).

Haematopoiesis in fish and mammals is a complex process, and many aspects regarding its model and the differentiation of haematopoietic stem cells (HSCs) still remain enigmatic despite advanced studies. The effects of microenvironmental factors or HSCs niche and signalling pathways on haematopoiesis are also unclear. This review presents Danio rerio as a model organism for studies on haematopoiesis in vertebrates and discusses the development of this process during the embryonic period and in adult fish. It describes the role of the microenvironment of the haematopoietic process in regulating the formation and function of HSCs/HSPCs (hematopoietic stem/progenitor cells) and highlights facts and research areas important for haematopoiesis in fish and mammals.

Effects of microenvironmental factors on assessing nanoparticle toxicity

Nanoparticles, such as dust or fine particles, are regarded as hazardous materials to human organs, and the interest in understanding their biological mechanisms and cellular response of nanoparticles is growing.

Proposed Models of Functional Heterogeneity in Cancer and the Effects of Microenvironmental Factors on Cancer Stem Cells: A Literature Review

Introduction: Functional heterogeneity in cancer may result in the metastasis of various types of tumour cells throughout the body. Attempting to explain functional heterogeneity in cancer cells has given rise to two models. The Cancer Stem Cell model proposes that a subset of tumour cells self-replicate and that heterogeneity is a progeny of various cancer stem cells (CSCs). The Clonal Evolution Model proposes heterogeneity as a product of mutations across tumour cells that accumulate and metastasize linearly or branching. Methods: Research was conducted through open-access journals and information was compiled surrounding CSC models using the Google Scholar and McMaster Library database search engines. Inclusions were sources that detailed the relationship between both models of functional heterogeneity and microenvironments and treatments. Literature that did not center around tumour microenvironments was not included in this literature review. Results: The two main models of tumour proliferation were explored and related to hypoxic tumour microenvironments. Various markers, etiologic agents and toxins were identified that contribute to tumour progression. Cell signalling and pathways that contribute to major cellular functions were identified, along with possible disruptions and epigenetic changes that lead to tumour and CSC proliferation. Discussion: This study reveals that the tumour microenvironment plays a large role in the proliferation of CSCs. Although the therapies targeting microenvironments are in early stages of development, focusing on these CSC targeted- therapies may lead to better treatments for cancer or more effective combination therapies. Strengths of the paper include the compilation of major contributing areas to CSC proliferation, whereas limitations encompass the high variability of tumour cells that are not all covered in this review. Conclusion: While no definitively eradicating treatment for CSCs currently exist, the recent developments in cancer research indicate promising new techniques for its management. Implications: By further studying malignant CSCs, highly effective cancer treatments may result, leading to the advancement of CSC recognition and combination therapy.

Effects of micro-environmental factors on the photoautotrophic growth of Hibiscus sagittifolius Kurz cultured in vitro

The arrow leaf abelmoschus rhizome (Hibiscus sagittifolius Kurz), or Sam Bo Chinhin Vietnamese, is a perennial suffrutex herb from which the tuber root is used as a medicine in folk remedy. This species is widely distributed and can be found on many terrains across South East Asia. With an aim to create a large number of uniform and high-quality H. sagittifolius transplants in vitro, effects of some environmental factors such as photoperiod and temperature on the photoautotrophic growth of H. sagittifoliusin vitro plants were investigated. In vitro single nodal cuttings, each with an unfolded leaf, were cultured photoautotrophically (without sucrose and vitamins) on mineral SH medium, under light intensity of 150 µmol m-2 s-1, temperature of 24oC ± 2oC, relative humidity (RH) of 55% ± 5% and three different photoperiods (8, 12 or 16 h d-1) in the first experiment. Commercial polypropylene bags (V = 1,000 ml), attached with two filter-paper membranes, were used as culture vessels. After 42 days of culture, H. sagittifolius plants under the photoperiod of 16 h d-1 had the greatestincreased fresh weight (502.3 mg/plt), increased dry weight (39.5 mg/plt) and leaf area (17.0 cm2) than those put under 8 hd-1or 12 h d-1. In addition, H. sagittifolius plants also showed statistical differences in growth when photoautotrophically cultured in different air temperature regimes, including 28/25oC (photo-/dark period), 25/25oC and 20/25oC. Increased fresh weight (775 mg/plt), increased dry weight (62 mg/plt) and leaf area (22.7 cm2) of in vitro H. sagittifolius plants were the greatest when temperature was maintained at 28 oC during photoperiod. On the contrary, the photoperiod temperature of 20oC resulted in the shortest shoot length and root length of H. sagittifoliusplants. In conclusion, this study proved that H. sagittifolius plants had the best growth when cultured on SH medium, without sucrose and vitamins supplementation, under light intensity of 150 µmol m-2 s-1, RH 55% ± 5%, photoperiod of 16 h d-1, temperature regime of 28/25oC(photo-/dark period). Citation: Nguyen Thuy Phuong Duyen, Tran Thi Van, Nguyen Le Thu Minh, Nguyen Thi Quynh, 2017. Effects of micro-environmental factors on the photoautotrophic growth of Hibiscus sagittifolius Kurz cultured in vitro. Tap chi Sinh hoc, 39(4): 496-506. DOI: 10.15625/0866-7160/v39n4.11030. *Corresponding author: qtnguyen_vn@yahoo.comReceived 7 September 2017, accepted 15 December 2017

The effect of microenvironmental factors on the development of myeloma cells.

Multiple myeloma (MM) is a clonal B-cell malignancy characterized by the accumulation of monoclonal plasma cells (PCs) in the bone marrow and other tissues. Although there are several new therapies, MM remains fatal. The interaction between MM cells and the bone marrow microenvironment promotes drug resistance and cancer cells survival. In our present work, we compared the antigen expression pattern of normal and pathological PCs and investigated the possible connections between various surface receptors, adhesion molecules, and recurrent genetic aberrations. We showed that the expression of CD29, CD27, and CD81 is lower in MM cells than in normal PCs. We found correlation of chromosome 11 hyperdiploidity and the decrease of CD27 expression. We demonstrated that MM cells with CD20 positivity also have CD28 expression. Multiple myeloma patients with active CD29 showed better response to treatment. Our results suggest that these changes may result in an alteration of the interaction between stromal cell and MM cell facilitating cell survival and the development of a more aggressive and resistant phenotype.

Human uterus myoma and gene expression profiling: A novel in vitro model for studying secretory leukocyte protease inhibitor-mediated tumor invasion

Secretory leukocyte protease inhibitor (SLPI) is a serine protease inhibitor that diminishes tissue destruction during inflammation. A recent report revealed high levels of SLPI expression in the oral carcinoma cell. In addition, overexpression of SLPI up-regulates metastasis in lung carcinoma cells. On the other hand, matrix metalloproteinases (MMPs) are proteinases that participate in extracellular matrix degradation. SLPI and MMPs are involved as accelerators of the tumor invasion process; however, their exact roles are not fully understood. Understanding the mechanism of tumor invasion requires models that take the effect of microenvironmental factors into account. In one such in vitro model, different carcinoma cells have been shown to invade myoma tissue in highly distinct patterns. We have used this myoma model, as it provides a more natural stroma-like environment, to investigate the role of SLPI in tumor invasion. Our results indicate that the model provides a relevant matrix for tumor invasion studies, and that SLPI is important for the invasion of oral carcinoma Ca9-22 cells in conjunction with MMPs. Furthermore, using bioinformatics analysis, we have identified candidates as key molecules involved in SLPI-mediated tumor invasion.

Does the Effect of Micro-Environmental Factors on a Street's Appeal for Adults' Bicycle Transport Vary across Different Macro-Environments? An Experimental Study.

BackgroundCharacteristics of the physical environment can be classified into two broad categories: macro- (“raw” urban planning features influenced on a regional level) and micro- (features specifically within a streetscape influenced on a neighborhood level) environmental factors. In urban planning applications, it is more feasible to modify conditions at the neighborhood level than at the regional level. Yet for the promotion of bicycle transport we need to know whether relationships between micro-environmental factors and bicycle transport depend on different types of macro-environments. This study aimed to identify whether the effect of three micro-environmental factors (i.e., evenness of the cycle path surface, speed limits and type of separation between cycle path and motorized traffic) on the street’s appeal for adults’ bicycle transport varied across three different macro-environments (i.e., low, medium and high residential density street).MethodsIn total, 389 middle-aged adults completed a web-based questionnaire consisting of socio-demographic characteristics and a series of choice tasks with manipulated photographs, depicting two possible routes to cycle along. Conjoint analysis was used to analyze the data.ResultsAlthough the magnitude of the overall effects differed, in each macro-environment (i.e., low, medium and high residential density), middle-aged adults preferred a speed limit of 30 km/h, an even cycle path surface and a hedge as separation between motorized traffic and the cycle path compared to a speed limit of 50 or 70 km/h, a slightly uneven or uneven cycle path surface and a curb as separation or no separation between motorized traffic and the cycle path.ConclusionsOur results suggest that irrespective of the macro-environment, the same micro-environmental factors are preferred in middle-aged adults concerning the street’s appeal for bicycle transport. The controlled environment simulations in the experimental choice task have the potential to inform real life environmental interventions and suggest that micro-environmental changes can have similar results in different macro-environments.

A41 Does the effect of micro-environmental factors on the appeal for adults’ transportation cycling vary across macro-environments? An experimental study using manipulating photographs

Abstract Background Micro-environmental factors, instead of macro-environmental factors (including walkability, access to shops/services/work, and urbanization), are easier to change in existing neighborhoods and thus more practical to target for environmental interventions. Unfortunately, relationships between transportation cycling and more changeable, micro-environmental factors are less consistent. Moreover, for interventions we need to know how well the findings can generalize to other macro-environments. This study aims to identify if the effect of micro-environmental factors (evenness of the cycle path, speed limitation and degree of separation) on the appeal for adults’ transportation cycling depends on macro-environmental factors. Methods Purposeful convenience sampling was used to recruit 389 middle-aged adults between 45 and 65 years. Participants completed a web-based questionnaire consisting of socio-demographic characteristics and a series of choice tasks with manipulated photographs using a choice based conjoint (CBC) method. Conjoint analysis was used to analyze the data. Results Although several interaction effects between the micro-environmental factors and the macro-environmental factor were significant, the direction of the effects across the different macro-environments did not differ, only the magnitude of the effect. Moreover, the macro-environment was clearly less important than the micro-environmental factors regarding the appeal for transportation cycling. Our results suggest that the strength of the main effects of the micro-environmental factors are mainly independent of the macro-environment and that the ranking of the relative importance of the three micro-environmental factors is similar in each macro-environment. Conclusions Findings obtained from this research could inform environmental interventions in real life settings to modify similar micro-environmental factors in different macro-environments.

Effects of micro environmental factors on natural killer activity (NK) of Beta Thalassemia major patients

The physiological mechanisms of decreased NK activity of β-Thalassemia major (BTM) patients are unknown. To assess in vitro effects of mononuclear cells and their cytokine secretion on NK activity, we compared activator receptor levels and cytotoxic activity of purified NK cells and NK cells in mononuclear cells (MNC) pools. We collected cell supernatant from unincubated and incubated MNC with K562 cells and measured their secreted cytokines levels. CD16 was lower on the surface of NK cells in MNC pools from BTM patients compared to healthy volunteers. This inhibition does not appear when NK cells were purified. NKp30 levels in NK cells decreased both as purified cells and as part of a pool of MNC in BTM patients. After incubation of MNC pools with K562 target cells, we found that supernatant levels of IL10, TGFβ1 and IL15 cytokines were also significantly higher in BTM patients compared to healthy volunteers.

Effect of forest disturbance on myxomycete assemblages in the southwestern Peruvian Amazon

Although the effects of microenvironmental factors on distribution patterns in myxomycetes have been investigated, studies of the responses of this group of organisms to different regimes of forest disturbance are relatively few in number. In an effort to understand the implications of forest fragmentation and habitat loss on myxomycetes, the project described herein was carried out at the Los Amigos Biological Station in southeastern Peru. The structure and composition of assemblages of myxomycetes were investigated in relation to three different forest types and climatic periods in the area of study. An analysis of the most commonly recorded substrates was carried out as well. The results suggested that habitat loss, through differences in forest structure, was the factor determining most of the differences in fruiting body abundance of myxomycetes among forest types. In addition, a switch in the ecological strategy of dispersal seemed to be an important factor accounting for differences in the fruiting body abundance and structure of assemblages of myxomycetes between collecting periods. This study provides evidence indicating that for microbial assemblages to maintain the balance of functional interactions within a particular forest ecosystem, the conservation of the forests themselves should be considered.

Effects of microenvironmental factors on rooting of <I>Juniperus scopulorum</I> cuttings

Effects of microenvironmental factors on rooting of <I>Juniperus scopulorum</I> cuttings

Effect of micro-environmental factors on natural regeneration of Sal (Shorea robusta)

Micro-environmental factors viz., soil moisture and light intensity are important factors that affect natural regeneration in forests. These factors vary spatially depending on the overhead canopy density of the forest. The present study focused on studying the effect of variation of soil moisture and light intensity on natural regeneration of sal species (Shorea robusta) under different micro-environments due to overhead canopy of varying forest density. Experimental plots of 40m× 40m size were laid under different overhead canopy densities in a small sal forested watershed in the foot hills of Himalayas in Nainital District of Uttarakhand State, India. The plots were monitored on a long term basis for soil moisture at multi depths, light intensity and natural regeneration of sal. The results of the study revealed that the natural regeneration was highest under C1 (up to-0.30) canopy followed by C2 (0.30–0.50), and C3 (0.50–0.70) canopies. The C3 canopy showed the dying back of sal shoots over 4 years of study. The highest R2 value of linear regression between incremental score of plot regeneration and average soil moisture content was obtained as 0.156 for average soil moisture content during non-monsoon months at 100 cm depth. The R2 value between incremental score of plot regeneration and annual average light intensity was obtained as 0.688 which indicated that the regeneration is largely dependent on the light intensity conditions during the year. The multiple linear regression analysis between the incremental score of regeneration and the average light intensity and average soil moisture content revealed that that about 80% of variation in regeneration is explained by both the factors.

2016 Effects of microenvironmental factors on the uptake, metabolism, and cytotoxicity of the bioreductive alkylating agents

2016 Effects of microenvironmental factors on the uptake, metabolism, and cytotoxicity of the bioreductive alkylating agents

Chemical Carcinogenesis in the Tracheobronchial Epithelium

Some of the recent work in pulmonary carcinogenesis is briefly reviewed. Morphologic studies of neoplastic and preneoplastic lesions of the human bronchi are compared with similar studies of carcinogenesis and epithelial regeneration in the hamster trachea. These studies suggest that bronchogenic carcinomas are typically complex mixtures of three basic phenotypes, the epidermoid and the mucous and dense-core granulated (endocrine) phenotypes. Pure forms of these phenotypes are rare, as different cells and even individual cells in single tumors express more than one phenotype. The clinical significance of such phenotypic variability is not yet known. Bronchial cell types which retain the capacity to divide include the mucous cell, the basal cell and perhaps the dense-core granulated cell. Studies of epithelial regeneration and preneoplastic lesions suggest that the mucous cell may be pivotal both in the response to injury and in carcinogenesis. Cigarette smoking is believed to be the major etiologic factor in bronchogenic carcinoma. Cigarette smoke contains initiators of carcinogenesis, but it contains a plethora of probable promoters and cocarcinogens as well. It is hypothesized that cigarette smoke may both initiate bronchial cells and promote carcinogenesis in cells which have previously been initiated by smoke or other factors. It is further hypothesized that that mucous cell is the major target for initiation and subsequent tumorigenesis. The ultimate phenotype(s) displayed by the tumor is suggested to result from the effect of microenvironmental factors upon the initiated cell and its progeny.

Chemical carcinogenesis in the tracheobronchial epithelium.

Some of the recent work in pulmonary carcinogenesis is briefly reviewed. Morphologic studies of neoplastic and preneoplastic lesions of the human bronchi are compared with similar studies of carcinogenesis and epithelial regeneration in the hamster trachea. These studies suggest that bronchogenic carcinomas are typically complex mixtures of three basic phenotypes, the epidermoid and the mucous and dense-core granulated (endocrine) phenotypes. Pure forms of these phenotypes are rare, as different cells and even individual cells in single tumors express more than one phenotype. The clinical significance of such phenotypic variability is not yet known. Bronchial cell types which retain the capacity to divide include the mucous cell, the basal cell and perhaps the dense-core granulated cell. Studies of epithelial regeneration and preneoplastic lesions suggest that the mucous cell may be pivotal both in the response to injury and in carcinogenesis. Cigarette smoking is believed to be the major etiologic factor in bronchogenic carcinoma. Cigarette smoke contains initiators of carcinogenesis, but it contains a plethora of probable promoters and cocarcinogens as well. It is hypothesized that cigarette smoke may both initiate bronchial cells and promote carcinogenesis in cells which have previously been initiated by smoke or other factors. It is further hypothesized that that mucous cell is the major target for initiation and subsequent tumorigenesis. The ultimate phenotype(s) displayed by the tumor is suggested to result from the effect of microenvironmental factors upon the initiated cell and its progeny.