Hatching Success of Mayfly Eggs at Low pH

1988 ◽  
Vol 45 (9) ◽  
pp. 1649-1652 ◽  
Author(s):  
Locke Rowe ◽  
Jeffrey Hudson ◽  
Michael Berrill
Keyword(s):  
Hatching Success ◽  
Low Ph ◽  
Soft Water ◽  
The Other ◽  
Hatching Rate ◽  
Field Surveys ◽  
Acid Sensitivity ◽  
Significant Mortality

Eggs of the mayflies Leptophlebia cupida, Habrophlebia vibrans, Stenonema femoratum, and Baetis flavistriga were reared in soft water at several pH levels (4.0, 4.5, 5.0, and 6.5) in the laboratory. The proportion of eggs undergoing eclosion did not vary with pH. However, in B. flavistriga, significant mortality of nymphs occurred before the hatch was complete at pH 4.0 (91%) and 4.5 (12%). Hatching rate of H. vibrans was significantly retarded at pH 4.0, 4.5, and especially at pH 5.0, but was unaffected in the other three species. The effects of elevated [H+] on these species are in agreement with their relative acid sensitivity inferred from field surveys.

scholarly journals Pollution Characteristics, Distribution and Ecological Risk of Potentially Toxic Elements in Soils from an Abandoned Coal Mine Area in Southwestern China

Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 330
Author(s):  
Libo Pan ◽  
Xiao Guan ◽  
Bo Liu ◽  
Yanjun Chen ◽  
Ying Pei ◽  
...  
Keyword(s):  
Ecological Risk ◽  
Toxic Elements ◽  
Low Ph ◽  
Potentially Toxic Elements ◽  
Point Sources ◽  
The Other ◽  
Guizhou Province ◽  
Pollution Level ◽  
Agricultural Activity ◽  
Background Values

Acid mine drainage (AMD) from abandoned coal mines can lead to serious environmental problems due to its low pH and high concentrations of potentially toxic elements. In this study, soil pH, sulfur (S) content, and arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), zinc (Zn), iron (Fe), manganese (Mn), and mercury (Hg) concentrations were measured in 27 surface soil samples from areas in which coal-mining activities ceased nine years previously in Youyu Catchment, Guizhou Province, China. The soil was acidic, with a mean pH of 5.28. Cadmium was the only element with a mean concentration higher than the national soil quality standard. As, Cd, Cu, Ni, Zn, Mn, Cr, and Fe concentrations were all higher than the background values in Guizhou Province. This was especially true for the Cd, Cu, and Fe concentrations, which were 1.69, 1.95, and 12.18 times their respective background values. The geoaccumulation index of Cd and Fe was present at unpolluted to moderately polluted and heavily polluted levels, respectively, indicating higher pollution levels than for the other elements in the study area. Spatially, significantly high Fe and S concentrations, as well as extremely low pH values, were found in the soils of the AMD sites; however, sites where tributaries merged with the Youyu River (TM) had the highest Cd pollution level. Iron originated mainly from non-point sources (e.g., AMD and coal gangues), while AMD and agricultural activity were the predominant sources of Cd. The results of an eco-risk assessment indicated that Cd levels presented a moderate potential ecological risk, while the other elements all posed a low risk. For the TM sites, the highest eco-risk was for Cd, with levels that could be harmful for aquatic organisms in the wet season, and may endanger human health via the food chain.

Limnetic Zooplankton Assemblages in Atlantic Canada with Special Reference to Acidification

1986 ◽  
Vol 43 (2) ◽  
pp. 444-456 ◽  
Author(s):  
J. C. H. Carter ◽  
W. D. Taylor ◽  
R. Chengalath ◽  
D. A. Scruton
Keyword(s):  
Nova Scotia ◽  
New Brunswick ◽  
Fish Predation ◽  
Low Ph ◽  
Buffering Capacity ◽  
The Other ◽  
Bay Of Fundy ◽  
Factor Scores ◽  
Multiple Discriminant Analysis ◽  
Biological Factors

Crustacean and rotifer plankton assemblages of 93 lakes in Labrador, 107 in Newfoundland, and 142 in New Brunswick – Nova Scotia were investigated for evidence of correlations with lake morphometric, chemical, or biological factors. Labrador assemblages were almost completely lacking in identifiable structure. Newfoundland species clustered into two groups of different body size, suggesting the influence of fish predation. Only one species in Labrador and Newfoundland was significantly correlated with a derived factor related to lake water buffering capacity. New Brunswick – Nova Scotia species clustered into two groups, one featuring significant positive and the other significant negative correlations with the buffering factor. From this we conclude that acidification is having an impact on the limnetic zooplankton of these two provinces. Multiple discriminant analysis was used to demonstrate that New Brunswick – Nova Scotia lakes differing in their buffering capacity were also distinct in zooplankton composition. Lakes with low factor scores (low pH, alkalinity, and calcium) were mainly located in the Bay of Fundy region; this area has above average fog and precipitation, and lies within the summer air flow carrying pollutants from the south.

Inter- and Intra-specific Variability in the Response of Zooplankton to Acid Stress

1985 ◽  
Vol 42 (11) ◽  
pp. 1749-1754 ◽  
Author(s):  
Edmund E. Price ◽  
Michael C. Swift
Keyword(s):  
Natural Populations ◽  
Daphnia Pulex ◽  
Acid Stress ◽  
Intraspecific Variability ◽  
Early Summer ◽  
Low Ph ◽  
Acid Sensitivity ◽  
Chaoborus Americanus ◽  
Acute Bioassays ◽  
Mesocyclops Edax

We measured the toxicity of sulfuric acid to natural populations of Daphnia pulex, D. galeata mendotae, Simocephalus serrulatus, Mesocyclops edax, Chaoborus americanus, and C. punctipennis. Organisms were collected in the spring and fall from acidic (pH 5.4) and circumneutral (pH 6.3–7.5) ponds, and their response to low pH was compared in 48- or 96-h acute bioassays. Based on 48- and 96-h LC50, cladocerans were most susceptible to acid stress, followed by Mesocyclops and Chaoborus larvae. Simocephalus was the most tolerant cladoceran, followed by D. pulex then D. galeata mendotae. Daphnia populations tested in the spring or early summer were more tolerant of low pH than those tested in the fall. Mesocyclops edax from an acid pond were more tolerant than those from a neutral pond. The response of the two Chaoborus species to low pH were quite similar; their 96-h LC50 (2.00, 2.09) was two pH units lower than those of cladocerans and one pH unit lower than that of M. edax. Our data demonstrate interspecific variability in acid sensitivity and suggest intraspecific variability due to habitat and season.

Studies on the к-casein complex: II. The isolation of a sialic acid-containing fraction by disrupting the complex at low pH in the presence of sodium chloride

1965 ◽  
Vol 32 (1) ◽  
pp. 57-63 ◽  
Author(s):  
R. Beeby
Keyword(s):  
Sialic Acid ◽  
Sodium Chloride ◽  
Deae Cellulose ◽  
Low Ph ◽  
The Other ◽  
Trichloracetic Acid ◽  
Complex Ii ◽  
Total Sialic Acid

SummaryWhen crude к-casein was precipitated at pH 3 in the presence of 0·4m-NaCl the supernatant contained up to 80% of the total sialic acid but no detectable cystine or cysteine. Two fractions were obtained from this supernatant by chromatography on DEAE cellulose; one containing 4–6% sialic acid and the other only onetenth of this amount.Most of the sialic acid of the sialic acid-rich fraction was soluble in 12% trichloracetic acid following treatment with rennin. It is suggested that the glycopeptide released by the action of the enzyme on casein originates from this fraction.

scholarly journals Identificação de Unidades de Paisagem: metodologia aplicada a Portugal Continental

Finisterra ◽  
2012 ◽  
Vol 36 (72) ◽  
Author(s):  
Teresa Pinto Correia ◽  
António Cancela Abreu ◽  
Rosário Oliveira
Keyword(s):  
Spatial Planning ◽  
Satellite Images ◽  
Methodological Approach ◽  
Subjective Assessment ◽  
The Other ◽  
Field Surveys ◽  
Flexible Approach ◽  
Landscape Units ◽  
The One ◽  
The University

IDENTIFICATION AND CHARACTERISATION OF LANDSCAPE IN PORTUGAL –This paper presents the concepts and methodology used in the study «Identification and characterisation of landscape in continental Portugal» undertaken by theDepartment of Landscape and Biophysical Planning of the University of Evora for the General Directorate for Spatial Planning and Urban Development (DGOT-DU) at the Ministry of the Environment and Spatial Planning, between 1999 and 2001. On the one hand, the methodological approach developed is based on the methodologies used recently for the same purpose in different European countries and on the way landscape has been considered in various European documents in the last years. On the other hand, it is also based on the team’s concern to approach the landscape as an holistic entity, and to examine its various components: ecological, cultural, socio-economic and sensorial. The set aim has been to define landscape units and to characterize these units in relation to the present landscape and the recorded trends, related problems and possibilities. Thus, the cartography relative to selected variables has been combined and related to satellite images and field surveys. The results of cross-referencing all this information has than been combined with expert examination of landscape coherence and character within each unit. The assessment was completed after careful bibliographic research and consultation with regional experts. The result is a flexible approach that combines objective analysis with a more subjective assessment, which the team considered fundamental for a true understanding of landscape.

scholarly journals THE ABSORPTION SPECTRUM OF VISUAL PURPLE

1938 ◽  
Vol 21 (4) ◽  
pp. 411-430 ◽  
Author(s):  
Aurin M. Chase ◽  
Charles Haig
Keyword(s):  
Absorption Spectrum ◽  
Absorption Spectra ◽  
Light Transmission ◽  
Low Ph ◽  
The Other ◽  
Distilled Water ◽  
Color Purity ◽  
Chemical Combination ◽  
Ph Range ◽  
Sensitive Group

The absorption spectra of visual purple solutions extracted by various means were measured with a sensitive photoelectric spectrophotometer and compared with the classical visual purple absorption spectrum. Hardening the retinas in alum before extraction yielded visual purple solutions of much higher light transmission in the blue and violet, probably because of the removal of light-dispersing substances. Re-extraction indicated that visual purple is more soluble in the extractive than are the other colored retinal components. However, the concentration of the extractive did not affect the color purity of the extraction but did influence the keeping power. This suggests a chemical combination between the extractive and visual purple. The pH of the extractive affected the color purity of the resulting solution. Over the pH range from 5.5 to 10.0, the visual purple color purity was greatest at the low pH. Temperature during extraction was also effective, the color purity being greater the higher the temperature, up to 40°C. Drying and subsequent re-dissolving of visual purple solutions extracted with digitalin freed the solution of some protein impurities and increased its keeping power. Dialysis against distilled water seemed to precipitate visual purple from solution irreversibly. None of the treatments described improved the symmetry of the unbleached visual purple absorption spectrum sufficiently for it to resemble the classical absorption spectrum. Therefore it is very likely that the classical absorption spectrum is that of the light-sensitive group only and that the absorption spectra of our purest unbleached visual purple solutions represent the molecule as a whole.

scholarly journals Role of Vitamin E on Indomethacin induced low pH of Seminal Fluid in Long Evans Rats

1970 ◽  
Vol 8 (1) ◽  
pp. 13-15
Author(s):  
Md Jahangir Alam ◽  
Humaira Naushaba ◽  
Uttam Kumar Paul ◽  
Tahmina Begum ◽  
Sunjida Shahriah ◽  
...  
Keyword(s):  
Body Weight ◽  
Vitamin E ◽  
Seminal Fluid ◽  
Low Ph ◽  
The Other ◽  
Testicular Damage ◽  
Other Hand ◽  
Long Evans ◽  
Different Doses

Context: Indomethacin is the most commonly and widely used nonsteroidal antinflammatory analgesic and antipyretic drug. Though it is effective drug in various diseases, indomethacin causes inhibition of spermatogenesis by lowering the pH of seminal fluid leading to infertility. On the other hand, vitamin E enhances spermatogenesis by increasing pH of the seminal fluid. Therefore, the present study was designed to observe the protective role of vitamin E on indomethacin induced low pH of seminal fluid in testicular damage. Objective: To observe the effects of vitamin E on indomethacin induced low pH of seminal fluid in testicular damage in Long Evans rats. Study design: An experimental study. Place and period of study: The study was carried out in the Department of Anatomy, Sir Salimullah Medical College, Dhaka in the period of August, 2005 to June, 2006. Materials and methods: Eightyfour mature Long Evans male rats were divided into four groups (I, II, III and IV). The rats of group I, II and III were treated with indomethacin at different doses and duration. Group IV rats were treated with indomethacin plus vitamin E at different doses for 49 days. The pH of seminal fluid were measured biochemically. Results: There was significant reduction (P<0.001) of pH of seminal fluid when the rats were treated with indomethacin at low (2 mg/kg body weight/day) and high (10 mg/kg body weight/day) doses for 7, 14 and 42 days, respectively. On the other hand, rats treated with indomethacin plus vitamin E for 49 days showed increase in pH of seminal fluid compared to other groups (P<0.001). Conclusion: It can be concluded from the study that vitamin E has potential role in the prevention of the antispermatogenic effects of indomethacin by increasing the pH of seminal fluid. Key words: seminal fluid; indomethacin; vitamin E   DOI: 10.3329/bja.v8i1.6103 Bangladesh Journal of Anatomy January 2010, Vol. 8 No. 1 pp. 13-15

Effect of pH on Glycolate and Ammonia Excretion in L-MSO Treated Chlorella Cells

1987 ◽  
Vol 42 (5) ◽  
pp. 525-529
Author(s):  
Yoshihiro Shiraiwa ◽  
Georg H. Schmid
Keyword(s):  
Chlorella Vulgaris ◽  
Major Part ◽  
Ammonia Excretion ◽  
Low Ph ◽  
Final Concentration ◽  
The Other ◽  
Effect Of Ph ◽  
Photosynthetic Rates ◽  
Ph Values ◽  
Glycolate Metabolism

Abstract The effect of pH changes on the excretion of ammonia and glycolate from algal cells into the medium was investigated in L-MSO (final concentration, 0.5 mм) -treated High-and Low CO2-cells of Chlorella vulgaris 211-11 h. The excretion was analyzed in the condition in which the cells were continuously gassed with air at 25 °C. At the values tested, generally more ammonia was excreted in L-MSO-treated Low CO2-cells than in L-MSO treated High CO2-cells. In both kinds of algal cells more ammonia was excreted at low pH-values and absolutely no ammonia was excreted at pH 8. In the dark, no or only slight ammonia excretion was observed in both L-MSO-treated High and Low CO2-cells. Under all these conditions no or only very low glycolate excretion was observed in both L-MSO treated High and Low CO2-cells. In High CO2-cells rates of photosynthesis were high at pH 6 and lower at higher pH values. On the other hand Low CO2-cells showed practically little dependence of photosynthetic rates on the pH. This result might indicate that the major part of the ammonia excretion observed, was not due to the inhibition of photosynthesis at acid pH values. It is known that ammonia excretion in L-MSO treated algal cells is due to the inhibition of the refixation of ammonia which originates from the glycine-serine aminotransferase reaction in the glycolate pathway. Our results demonstrate that glycolate production and glycolate metabolism are more intense at low pH values when compared to high pH values. This is valid for both High and Low CO2-cells. Low CO2-cells in Chlorella vulgaris 211-11 h exhibit a more active glycolate metabolism than High CO2-cells.

Reproductive Success of Amnicola limosa (Gastropoda) in Low Alkalinity Lakes in South-Central Ontario

1989 ◽  
Vol 46 (5) ◽  
pp. 863-869 ◽  
Author(s):  
Margo A. Shaw ◽  
Gerald L. Mackie
Keyword(s):  
Life Cycle ◽  
Reproductive Success ◽  
Hatching Success ◽  
Low Ph ◽  
Critical Stage ◽  
Percent Survival ◽  
South Central ◽  
Order Of Magnitude ◽  
Magnitude Difference

The reproductive success of the gastropod Amnicola limosa was examined in six lakes ranging in pH from 4.62 to 7.42 to determine which stages in the life cycle were most sensitive to acidification. Although fecundity was significantly greater (p < 0.01) for adults reared at pH 7.42 than at pH 5.89–6.64, a failure to oviposit was documented only at pH 4.62. Hatching success was uniformly high (88–97%) at pH 5.59 to 7.42, while embryos incubated at pH 4.62 suffered complete mortality. The most critical stage in the life cycle is the newly hatched stage. Survival during the 20 d post hatch ranged from 23% at pH 5.59 to 69% at pH 7.42. There was an order of magnitude difference in the cumulative percent survival of recruits in lakes ranging in pH from 5.59 (5.1%) to 7.42 (44.0%). Juveniles raised at low pH (5.59–5.70) were on average 0.20 mm (20%) smaller than those in circumneutral lakes (pH 6.64–7.42). The present low densities of Amnicola limosa in Heney Lake (pH 5.59) can be explained by low recruitment since 1980. Evidence presented suggests that the disappearance of this species from clear low pH lakes (pH < 5.8) is due to reductions in fecundity and hatchling survival.

scholarly journals Effect of various co-culture systems on embryo development in ovine

2013 ◽  
Vol 58 (No. 10) ◽  
pp. 443-452 ◽  
Author(s):  
B. Heidari ◽  
A. Shirazi ◽  
M.-M. Naderi ◽  
M.-M. Akhondi ◽  
H. Hassanpour ◽  
...  
Keyword(s):  
Embryo Development ◽  
Culture System ◽  
Cell Number ◽  
Culture Conditions ◽  
The Other ◽  
Culture Period ◽  
Hatching Rate ◽  
Embryonic Fibroblast ◽  
One Way Anova

Considering the advent of mesenchymal stem cells (MSCs) as a new source of somatic cells in embryo co-culture system, the current study was aimed to compare in vitro embryo development using embryonic MSCs monolayer with embryonic fibroblast cells (EFCs), oviductal epithelial cells (OECs), and cell-free culture system. The IVM/IVF presumptive sheep zygotes were randomly cultured in different culture conditions as follows: (1) SOFaaBSA medium for the whole culture period (SOF, n = 371), (2) SOFaaBSA medium for the first 3 days followed by co-culturing with MSCs for the next 5 days (SOF-MSCs, n = 120), (3) co-culturing with MSCs for the first 3 days followed by culture in SOFaaBSA medium for the next 5 days (MSCs-SOF, n = 133), (4) co-culturing with MSCs for the whole culture period (MSCs, n = 212), (5) SOFaaBSA medium for the first 3 days followed by co-culturing with EFCs for the next 5 days (SOF-EFCs, n = 132), (6) co-culturing with EFCs for the first 3 days followed by culture in SOFaaBSA medium for the next 5 days (EFCs-SOF, n = 165), (7) co-culturing with EFCs for the whole culture period (EFCs, n = 236), and (8) co-culturing with OECs for the whole culture period (OECs, n = 255). One-Way ANOVA by multiple pairwise comparisons using Tukey&rsquo;s test was performed. Co-culturing in MSCs group had no superiority over EFCs and OECs groups. Though, when co-culturing with MSCs and EFCs was limited to the first 3 days of culture, the embryo development indices were improved compared to the other co-cultured groups. Considering both the hatching rate and total cell number, the application of MSCs for the first 3 days of culture (MSCs-SOF) was superior to the other co-culture and SOF groups. &nbsp;

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