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Int. J. Environ. Res. Public Health, Volume 5, Issue 2 (June 2008) – 7 articles , Pages 86-124

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101 KiB  
Article
Juvenile Hormone Analogues, Methoprene and Fenoxycarb Dose-Dependently Enhance Certain Enzyme Activities in the Silkworm Bombyx Mori (L)
by Devi M. Mamatha, Vijaya K. Kanji, Hari H. P. Cohly and M. Rajeswara Rao
Int. J. Environ. Res. Public Health 2008, 5(2), 120-124; https://doi.org/10.3390/ijerph5020120 - 30 Jun 2008
Cited by 14 | Viewed by 9467
Abstract
Use of Juvenile Hormone Analogues (JHA) in sericulture practices has been shown to boost good cocoon yield; their effect has been determined to be dose-dependent. We studied the impact of low doses of JHA compounds such as methoprene and fenoxycarb on selected key [...] Read more.
Use of Juvenile Hormone Analogues (JHA) in sericulture practices has been shown to boost good cocoon yield; their effect has been determined to be dose-dependent. We studied the impact of low doses of JHA compounds such as methoprene and fenoxycarb on selected key enzymatic activities of the silkworm Bombyx mori. Methoprene and fenoxycarb at doses of 1.0 μg and 3.0fg/larvae/48 hours showed enhancement of the 5th instar B. mori larval muscle and silkgland protease, aspartate aminotransaminase (AAT) and alanine aminotransaminase (ALAT), adenosine triphosphate synthase (ATPase) and cytochrome-c-oxidase (CCO) activity levels, indicating an upsurge in the overall oxidative metabolism of the B.mori larval tissues. Full article
626 KiB  
Article
Compartmentalization of Aquaporins in the Human Intestine
by Hari H. P. Cohly, Raphael Isokpehi and Rajendram V. Rajnarayanan
Int. J. Environ. Res. Public Health 2008, 5(2), 115-119; https://doi.org/10.3390/ijerph5020115 - 30 Jun 2008
Cited by 23 | Viewed by 9736
Abstract
Improper localization of water channel proteins called aquaporins (AQP) induce mucosal injury which is implicated in Crohn’s disease and ulcerative colitis. The amino acid sequences of AQP3 and AQP10 are 79% similar and belong to the mammalian aquaglyceroporin subfamily. AQP10 is localized on [...] Read more.
Improper localization of water channel proteins called aquaporins (AQP) induce mucosal injury which is implicated in Crohn’s disease and ulcerative colitis. The amino acid sequences of AQP3 and AQP10 are 79% similar and belong to the mammalian aquaglyceroporin subfamily. AQP10 is localized on the apical compartment of the intestinal epithelium called the glycocalyx while AQP3 is selectively targeted to the basolateral membrane. Despite the high sequence similarity and evolutionary relatedness, the molecular mechanism involved in the polarity, selective targeting and function of AQP3 and AQP10 in the intestine is largely unknown. Our hypothesis is that the differential polarity and selective targeting of AQP3 and AQP10 in the intestinal epithelial cells is influenced by amino acid signal motifs. We performed sequence and structural alignments to determine differences in signals for localization and posttranslational glycosylation. The basolateral sorting motif “YRLL” is present in AQP3 but absent in AQP10; while Nglycosylation signals are present in AQP10 but absent in AQP3. Furthermore, the C-terminal region of AQP3 is longer compared to AQP10. The sequence and structural differences between AQP3 and AQP10 provide insights into the differential compartmentalization and function of these two aquaporins commonly expressed in human intestines. Full article
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<p><span class="html-italic">Illustration of aquaporin homotetramer</span>. Water transport through pores 1–4 and an ion transport is predicted to occur via the central pore 5.</p>
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<p><b>A &amp; B</b>: Hydrophobic residues are displayed in stick representation (AQP3 in green and AQP10 in yellow)</p>
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<p><b>A &amp; B</b>: Polar residues are displayed in stick representation (AQP3 in green and AQP10 in yellow)</p>
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<p><b>A–D</b>: Surface rendering clearly shows polar areas and regions responsive to polar small molecular transport.</p>
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<p>Sequence alignment of human AQP3 and AQP10.</p>
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<p>Multiple sequence alignment of unique AQP3 obtained from NCBI GenBank</p>
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226 KiB  
Article
Preliminary Molecular Dynamic Simulations of the Estrogen Receptor Alpha Ligand Binding Domain from Antagonist to Apo
by T. Dwight McGee, Jesse Edwards and Adrian E. Roitberg
Int. J. Environ. Res. Public Health 2008, 5(2), 111-114; https://doi.org/10.3390/ijerph5020111 - 30 Jun 2008
Cited by 24 | Viewed by 11385
Abstract
Estrogen receptors (ER) are known as nuclear receptors. They exist in the cytoplasm of human cells and serves as a DNA binding transcription factor that regulates gene expression. However the estrogen receptor also has additional functions independent of DNA binding. The human estrogen [...] Read more.
Estrogen receptors (ER) are known as nuclear receptors. They exist in the cytoplasm of human cells and serves as a DNA binding transcription factor that regulates gene expression. However the estrogen receptor also has additional functions independent of DNA binding. The human estrogen receptor comes in two forms, alpha and beta. This work focuses on the alpha form of the estrogen receptor. The ERα is found in breast cancer cells, ovarian stroma cells, endometrium, and the hypothalamus. It has been suggested that exposure to DDE, a metabolite of DDT, and other pesticides causes conformational changes in the estrogen receptor. Before examining these factors, this work examines the protein unfolding from the antagonist form found in the 3ERT PDB crystal structure. The 3ERT PDB crystal structure has the estrogen receptor bound to the cancer drug 4-hydroxytamoxifen. The 4-hydroxytamoxifen ligand was extracted before the simulation, resulting in new conformational freedom due to absence of van der Waals contacts between the ligand and the receptor. The conformational changes that result expose the binding clef of the co peptide beside Helix 12 of the receptor forming an apo conformation. Two key conformations in the loops at either end of the H12 are produced resulting in the antagonist to apo conformation transformation. The results were produced over a 42ns Molecular Dynamics simulation using the AMBER FF99SB force field. Full article
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<p>Era from the 3ERT PDB crystal structure with the 4-Hydroxytamoxifen extracted from the binding pocket. The system was solvated with 15212 water molecules, shown here without hydrogen atoms. This image was produced using VMD software [<a href="#b13-ijerph-05-00111" class="html-bibr">13</a>].</p>
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<p>ERα simulation initial structure (blue), after about 20ns (red), and 42 ns yellow. The loop region at the head of Helix 12 is fluctuating due to the extraction of the ligand (4-Hydroxytamoxifen) that would have protruded out of the binding pocket. This image was produced from our Amber results using VMD software [<a href="#b13-ijerph-05-00111" class="html-bibr">13</a>].</p>
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<p>ERα simulation initial structure (blue), after about 20ns (red), and 42 ns yellow. The loop region at the head of Helix 12 is fluctuating due to the extraction of the ligand (4-Hydroxytamoxifen) that would have protruded out of the binding pocket. This image was produced from our Amber results using VMD software [<a href="#b13-ijerph-05-00111" class="html-bibr">13</a>].</p>
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74 KiB  
Article
Evaluation of the Effect of Ecologic on Root Knot Nematode, Meloidogyne incognita, and Tomato Plant, Lycopersicon esculenum
by Debora C. Ladner, Paul B. Tchounwou and Gary W. Lawrence
Int. J. Environ. Res. Public Health 2008, 5(2), 104-110; https://doi.org/10.3390/ijerph5020104 - 30 Jun 2008
Cited by 28 | Viewed by 11598
Abstract
Nonchemical methods and strategies for nematode management including cultural methods and engineered measures have been recommended as an alternative to methyl bromide (a major soil fumigant), due to its role in the depletion of the ozone layer. Hence, an international agreement has recently [...] Read more.
Nonchemical methods and strategies for nematode management including cultural methods and engineered measures have been recommended as an alternative to methyl bromide (a major soil fumigant), due to its role in the depletion of the ozone layer. Hence, an international agreement has recently been reached calling for its reduced consumption and complete phasing out. This present research evaluates the potential of Ecologic, a biological, marine shell meal chitin material, as a soil amendment management agent for root knot nematode, Meloidogyne incognita, control, and its effect on the growth of Floradel tomato plant, Lycopersicon esculentum. To accomplish this goal, studies were conducted during which, experimental pots were set up in greenhouse environments using sterilized soil inoculated with 5,000 root-knot eggs per 1500 g soil. There were 4 treatments and 5 replications. Treatments were: No chitin; 50 g chitin; 100 g chitin; and 200 g chitin. A two-week wait period following Ecologic amendment preceded Floradel tomato planting to allow breakdown of the chitin material into the soil. Fresh and dry weights of shoot and root materials were taken as growth end-points. A statistically significant difference (p ≤ 0.05) was obtained with regard to the growth rate of L. esculentum at 100 g chitin treatment compared to the control with no chitin. Mean fresh weights of Floradel tomato were 78.0 ± 22.3g, 81.0 ± 20.3g, 109.0 ± 25.4g and 102.0 ± 33.3g at 0, 50, 100 and 200g chitin, respectively. The analysis of root knot nematode concentrations indicated a substantial effect on reproduction rate associated with chitin amendment. Study results showed a significant decrease in both root knot nematode eggs and juveniles (J2) at 100g and 200g Ecologic chitin levels, however, an increase in nematode concentrations was recorded at the 50g Ecologic chitin level (p ≤ 0.05). The mean amounts of J2 population, as expressed per 1500cm3 soil, were 49,933 ± 38,819, 86,050 ± 25248, 103 ± 133 and 103 ± 133 for 0, 50, 100 and 200g chitin, respectively. Similarly, the mean numbers of root knot nematode eggs (per 1500cm3 of soil) were 40,759 ± 36,712, 66,048 ± 39,730, 9,904 ± 16,591 and 9,257 ± 17,204. Root gall rating was also significantly lower (p ≤ 0.05) at the 100g and 200g chitin levels compared to the control. Percent gall ratings were 3.3 ± 1.0%, 3.2 ± 1.0%, 1.0 ± 0.5%, and 1.0% ± 0.6% for amendment levels of 0, 50, 100, and 200g chitin, respectively. Full article
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<p>Effect of chitin amendment on the fresh weight of ‘Floradel’ tomato plant (<span class="html-italic">L. esculentum).</span> Data points represent means ± SDs. N=10.</p>
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<p>Effect of chitin amendment on the dry weight of ‘Floradel’ tomato plant (<span class="html-italic">L. esculentum).</span> Data points represent means ± SDs. N=10.</p>
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<p>Effect of chitin amendment on the concentration of root knot nematode (<span class="html-italic">M. incognita)</span> eggs on ‘Floradel’ tomato plant (<span class="html-italic">L. esculentum).</span> Data points represent means ± SDs. N=10.</p>
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<p>Effect of chitin amendment on the concentration of root knot nematode (<span class="html-italic">M. incognita)</span> juveniles on ‘Floradel’ tomato plant (<span class="html-italic">L. esculentum).</span> Data points represent means ± SDs. N=10.</p>
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<p>Effect of chitin amendment on gall rating of tomato plant in the presence of <span class="html-italic">M. incognita</span> nematodes. Data points represent means ± SDs, N=10. p ≤ 0.05.</p>
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57 KiB  
Article
Responses of Antioxidant Enzymes in Catfish Exposed to Liquid Crystals from E-Waste
by Ran An, Yadong Li, Xiaojun Niu and Hongtao Yu
Int. J. Environ. Res. Public Health 2008, 5(2), 99-103; https://doi.org/10.3390/ijerph5020099 - 30 Jun 2008
Cited by 51 | Viewed by 10487
Abstract
Liquid crystals (LCs) are typically elongated organic molecules with a non-uniform distribution of electrical charges leading to a dipole. LCs are widely used in displays of computers and other electronic devices. The rapid obsolescence rate of electronics results in large amounts of liquid [...] Read more.
Liquid crystals (LCs) are typically elongated organic molecules with a non-uniform distribution of electrical charges leading to a dipole. LCs are widely used in displays of computers and other electronic devices. The rapid obsolescence rate of electronics results in large amounts of liquid crystal displays (LCDs) entering the environment. Data on health effects of LCs on living creatures are currently limited to some acute toxicity tests by a few major LC manufacturers. These tests concluded that the vast majority of LCs are not acutely toxic. Since the amount of LCs in electronic devices is very small, the health effects of LCs at low concentrations or doses become important. Catfish were used as the test animals in this study. Four major enzymes of the fish’s antioxidant defense system catalase (CAT), superoxide dismutase (SOD), selenium-dependent glutathione peroxidase (Se-GPx), and glutathione-Stransferase (GST) were chosen as biomarkers to examine effects of LCs, which were taken from obsolete laptop personal computers made in the early 1990s. The catfish were fed with food containing different contents of LCs for 40 days. Activities of the four chosen enzymes in fish livers were assayed. The results showed that there were significant inductions of CAT, SOD, and Se-GPx activities in response to the LC doses. The plots of the enzyme activities versus LC doses suggested an occurrence of oxidative stress when the dose reached about 20 μg LC/g fish·d. It was concluded that LCs can cause pollutant-induced stress to catfish at low doses. CAT, SOD and Se-GPx are effective biomarkers to give early warning on potential health effects of LCs on some aquatic lives including catfish. Full article
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<p>Response of CAT activity in fish livers to LC dose</p>
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<p>Response of SOD activity in fish livers to LC dose</p>
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<p>Response of Se-GPx activity in fish livers to LC dose</p>
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<p>Response of GST activity in fish livers to LC dose</p>
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109 KiB  
Article
Heavy metals in water of the San Pedro River in Chihuahua, Mexico and its potential health risk
by Roberto L. Gutiérrez, Hector Rubio-Arias, Ray Quintana, Juan Angel Ortega and Melida Gutierrez
Int. J. Environ. Res. Public Health 2008, 5(2), 91-98; https://doi.org/10.3390/ijerph5020091 - 30 Jun 2008
Cited by 35 | Viewed by 13628
Abstract
The objective of this study was to determine the seasonal and downstream water quality variations of the San Pedro River in Chihuahua, Mexico. Water samples were collected monthly from October 2005 to August 2006 in triplicate, totaling 165 water samples. The five sampling [...] Read more.
The objective of this study was to determine the seasonal and downstream water quality variations of the San Pedro River in Chihuahua, Mexico. Water samples were collected monthly from October 2005 to August 2006 in triplicate, totaling 165 water samples. The five sampling locations were: below the Francisco I. Madero dam (LP); between Rosales and Delicias (RD); Meoqui (M); El Torreon (ET), and Julimes (LJ). The levels of As, Be, Ca, Cd, Co, Cu, Cr, Fe, Li, Mg, Mn, Mo, Ni, Pb, Sb, Se, Sr, Ti, Ta, V and Zn were measured using an Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) Perkin Elmer 2100. In addition, temperature, pH, electrical conductivity and total and fecal coliformes were determined. The statistical analysis considered a factorial treatment design; where factor A was the location point and factor B was sampling date. In addition, a multivariate technique looking for principal components was performed. The results indicated that some samples exceeded Mexican standards for As, Be, Ca, Cd, Co, Cr, Fe, Mn, Ni, Pb, Sb, Se, Sr and Zn. The As level must be considered for a red flag to the communities along the Rio San Pedro because both the monthly average level (0.10 mg L-1) and location (0.10 mg L-1) exceeded the Mexican and International norms. The multivariate analysis showed a predominant aggregation at the LP location, meaning that there was a predominance of As, Sr, Fe and Li. At the rest of the locations the elements did not present a tendency for aggregation. Statistics applied to sampling month showed that December, January, March and April were aggregated in a negative quadrant of component 1 indicating a predominance of V, Ni, Be, Fe and As. Overall, the results confirmed that this stretch of the San Pedro River is contaminated with heavy metals and other contaminants that might affect human health as well as the health of the ecosystem. Full article
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<p>Concentration of As in water considering five location points and 11 consecutive months of sampling (date 1 corresponds to October 2005)</p>
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<p>Interaction plot for Be in water considering five location points and 11 consecutive months of sampling (month 1 corresponds to October 2005)</p>
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<p>Interaction plot for Ca in water considering five location points and 11 consecutive months of sampling (month 1 corresponds to October 2005).</p>
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<p>Interaction plot for Co in water considering five location points and 11 consecutive months of sampling (month 1 corresponds to October 2005)</p>
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<p>Interaction plot for Cr in water considering five location points and 11 consecutive months of sampling (month 1 corresponds to October 2005)</p>
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<p>Interaction plot for Fe in water considering five location points and 11 consecutive months of sampling (month 1 corresponds to October 2005)</p>
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<p>Interaction plot for Li in water considering five location points and 11 consecutive months of sampling (month 1 corresponds to October 2005)</p>
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<p>Interaction plot for Mg in water considering five location points and 11 consecutive months of sampling (month 1 corresponds to October 2005)</p>
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<p>Main factors for Mn in water considering five sampling location and 11 consecutive sampling months (month 1 corresponds to October 2005)</p>
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104 KiB  
Article
Cross-Sectional Silica Exposure Measurements at Two Zambian Copper Mines of Nkana and Mufulira
by Patrick Hayumbu, Thomas G. Robins and Rosa Key-Schwartz
Int. J. Environ. Res. Public Health 2008, 5(2), 86-90; https://doi.org/10.3390/ijerph5020086 - 30 Jun 2008
Cited by 20 | Viewed by 13615
Abstract
We measured the quartz content of 20 bulk settled dust and 200 respirable dust samples in a cross-sectional dust exposure assessment that is part of an epidemiological study to ascertain the risk of nonmalignant respiratory diseases among Zambian copper miners. Dust samples were [...] Read more.
We measured the quartz content of 20 bulk settled dust and 200 respirable dust samples in a cross-sectional dust exposure assessment that is part of an epidemiological study to ascertain the risk of nonmalignant respiratory diseases among Zambian copper miners. Dust samples were collected from the copper mines of Mopani Copper Mine plc (Mufulira and Nkana Mines). Analytical measurements employed NIOSH Method 0600 for gravimetric analysis of respirable dust and NIOSH Method 7500 for quartz analysis in bulk and respirable dust samples. The measured quartz content of respirable dust showed that 59% and 26% of Mufulira and Nkana Mine samples, respectively, were above the calculated U.S. Occupational Safety and Health Administration permissible exposure limit. The mean intensities of respirable dust exposure at Mufulira and Nkana were 0.992 mg/m3 (range 0-7.674) and 0.868 mg/m3 (range 0-6.944), respectively while the mean intensities of respirable quartz at Mufulira and Nkana were 0.143 mg/m3 (range 0-1.302) and 0.060 mg/m3 (range 0-0.317), respectively. These results indicate weak dust monitoring at these mines which may increase the risk of nonmalignant disease in many miners. Since Zambian mining regulations do not have crystalline silica exposure limits, these results accord with the recommendation that Zambian mining houses and the government establish crystalline silica analysis laboratory capacity and adopt dust mass concentration occupational exposure limits for more protective dust monitoring of workers. Full article
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<p>MCM personal samples of respirable dust containing crystalline silica higher than specified U.S. OEL</p>
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