Distribution of acidophilic iron- and sulphur-oxidizing bacteria in a sulphur and iron sulphide mine

Abstract

The numbers of acidophilic iron- and sulphur-oxidizing chemolithotrophic bacteria, as well as certain physical and chemical environmental factors, were examined in weathered iron sulphide ores and acid mine drainage waters at the abandoned Matsuo sulphur and iron sulphide mine in Japan. In the ores, the population of iron-oxidizing bacteria was smaller than that of sulphur-oxidizing bacteria. On the other hand, an inverse relationship between iron- and sulphur-oxidizing bacteria was observed in the acid mine waters. The marked differences between the ores and acid mine waters in their numbers of iron- and sulphur-oxidizing bacteria, may reflect the availability and content of the respective energy sources: ferrous iron and elemental sulphur.     

Addition of erythrocytes to in vitro culture medium attenuates the detrimental effects of reactive oxygen species on bovine preimplantation embryo development

Erythrocytes were recently found to improve the early development of mice embryos by their antioxidant effect. The purpose of the present study was to examine the effect of erythrocytes on the in vitro development of bovine in vitro fertilized (IVF) embryos in medium supplemented with reactive oxygen species (ROS). IVF embryos were cultured in CR1aa medium supplemented with oxidizing agents, 0.5 mmol/L hypoxanthine and 0.01 U/mL xanthine oxidase (HX/XOD), in the presence and absence of erythrocytes (5 × 10⁴, 5 × 10⁵, 5 × 10⁶ and 5 × 10⁷ erythrocytes/mL). After 8 days, blastocysts were examined with a stereomicroscope. HX/XOD blocked development to the blastocyst stage (HX/XOD: 0%, control: 33%), but in the presence of both erythrocytes and HX/XOD, blastocyst development was restored to about one‐third to two‐thirds the normal rate (5 × 10⁵ to 5 × 10⁷ erythrocytes/mL: 12 to 23%). Furthermore, adding erythrocytes or erythrocyte hemolysate to medium without HX/XOD increased the blastocyst rate. These results suggest that the addition of erythrocytes can attenuate the detrimental effects of ROS on embryo development in bovine species as well as in mice.     

Effects of neem (Azadirachta indica) extracts onLeptocorisa chinensis under choice and no-choice conditions

Two extracts from neem (Azadirachta indica A. Juss. (Meliaceae)) seeds, azadirachtin and oil, and a mixture of neem oil and abamectin, were tested on second-instar nymphs of the rice bugLeptocorisa chinensis (Dallas) (Hemiptera: Alydidae). To clarify the effect of spraying coverage on bioefficacy of test materials, experiments were conducted under choice and no-choice conditions in field cages. In a choice test, treatment with the mixture of neem oil and abamectin was most effective in reducing the survival ofL. chinensis, followed by azadirachtin at 60 ppm, 30 ppm and 3% neem oil, whereas all treatments except neem oil caused 100% mortality within 3 weeks in a no-choice test. When second-instar nymphs had choices of treated and untreated plants within a treatment, no differences in yield and sum of dead and stained grains were found between those two choices, indicating that nymphs neither caused significant reduction in yield nor reduced the quality of untreated plants. Regardless of treatment, the difference in overall yield between treated and untreated plants under choice conditions was not statistically significant (P>0.05). Our results indicate that neem-based formulations, used alone or in combination with abamectin, have the potential to be integrated into the existing programs to control the rice bug. http://www.phytoparasitica.org posting Aug. 28, 2005.     

Effect of isoflurane anesthesia on hemodynamics following the administration of an angiotensin-converting enzyme inhibitor in cats

The objective of this study was to evaluate the hemodynamics of the anesthetic isoflurane in healthy cats given angiotensin-converting enzyme inhibitor (ACEI). The 7 healthy young cats and 3 old cats were received placebo or enalapril 0.5 mg/kg orally. The change in systolic arterial pressure from the baseline to 30 min postanesthesia in the ACEI group was significantly higher than in the placebo group (mean +/- SD: -39 +/- 13% vs. -17 +/- 12%, respectively). The present study indicated that general anesthesia may induce hypotension after the administration of an ACEI.     

Diurnal variations of blood pressure in dogs.

Using the telemetry system, we measured the blood pressure (BP) invasively in seven adult mongrels while unanesthetized and unbound. Post-operative BP after implanting the telemetry BP transmitter showed temporarily high values due to the invasive nature of the surgery. It was, however, observed that BP gradually decreased thereafter, and showed settled trends from the eighth day post-operatively. When we took the average of the systolic, mean and diastolic BP at hourly intervals for each of the dogs once their BP had settled, a twin peak diurnal variation (at 8:00 and 19:00) was observed. Moreover, significantly high values (p < 0.05) were identified in active state compared with when sleeping or at rest. The 24 hr BP measured by the telemetry system in seven normal dogs resulted in the following values: systolic 123.4 +/- 7.9 mmHg, mean 91.1 +/- 5.6 mmHg, and diastolic 74.5 +/- 4.9 mmHg.     

Changes in the levels of circulating plasma free amino acids of carp (Cyprinus carpio) after feeding a protein and an amino acid diet of similar composition

A protein diet containing casein as the sole nitrogen source and an amino acid diet of similar composition (except isolated amino acids represented all of the nitrogen) were fed to triplicate groups of yearling carp. The sequence of appearance of free amino acids in the plasma of carp at 0, 2, 4, 8 and 16 h after feeding the two diets was examined.The circulating levels of all plasma free essential amino acids were in highest concentrations at 4 h after feeding the casein diet, except for arginine which declined slightly from 2 to 4 h. After feeding the amino acid diet, plasma free arginine and lysine were at peak levels at 2 h after feeding, while others peaked by 4 h.Glutamic acid and aspartic acid were detected in very low concentrations in the plasma relative to their levels in the diets, while proline was found in the highest concentrations of all other amino acids.Essential amino acid levels in the plasma were found to be positively correlated with their levels in the diets, while non-essential amino acids were not.     

Epistatic effects between pairs of the growth hormone secretagogue receptor 1a,growth hormone,growth hormone receptor,non‐SMC condensin I complex,subunit G and stearoyl‐CoA desaturase genes on carcass,price‐related and fatty acid composition traits in Japanese Black cattle

Growth hormone secretagogue receptor 1a (GHSR1a), growth hormone (GH), growth hormone receptor (GHR), non‐SMC condensin I complex, subunit G (NCAPG) and stearoyl‐CoA desaturase (SCD), are known to play important roles in growth and lipid metabolisms. Single and epistatic effects of the five genes on carcass, price‐related and fatty acid (FA) composition traits were analyzed in a commercial Japanese Black cattle population of Ibaraki Prefecture. A total of 650 steers and 116 heifers for carcass and price‐related traits, and 158 steers for FA composition traits were used in this study. Epistatic effects between pairs of the five genes were found in several traits. Alleles showing strain‐specific differences in the five genes had significant single and epistatic effects in some traits. The data suggest that a TG‐repeat polymorphism of the GHSR1a.5′UTR‐(TG)_n locus plays a central role in gene–gene epistatic interaction of FA composition traits in the adipose tissue of Japanese Black cattle.     

Growth response of Tilapia zillii fingerlings fed isocaloric diets with variable protein levels

Six purified casein diets within a range of 21–53% crude protein were fed for 3 weeks to young tilapia (Tilapia zillii) to determine the optimum protein requirement and protein: energy ratio for growth. Growth rate increased proportionally to protein level of the diet to an incorporation rate of about 35%. Beyond this a gradual retardation in growth rate was observed. The diet containing about 30% crude protein with a protein: energy ($\text{P}\text{E}$) ratio of 81, however, appeared to be more efficiently utilized by the fish in terms of protein deposition and energy retention than diets with higher levels of crude protein. These results indicate that Tilapia zillii requires about 35% protein in the diet for optimum growth while 30% for the maximum bodily protein deposition when casein is used as the sole source of protein. All six diets, however, showed an excellent feed conversion. Protein efficiency ratio (PER) decreased with the increase in protein in the diet.     

Presence of micro-aggregates containing sulfate-reducing bacteria in a paddy-field soil

Micro-aggregates containing sulfate-reducing bacteria in a paddy-field soil were examined by enumerating the number of sulfate-reducing bacteria liberated when the soil was subjected to repeated washings with and without pretreatment by sonication. Soils sampled from both an oxidized surface-layer and a reduced plough-layer were subjected to repeated washings.The liberation of sulfate-reducing bacteria, expressed as log n, were calculated according to the equation N_i = N₀ (1/n)ⁱ. Where i is the number of repeated washings; N₀ is the number of cells per 1 ml supernatant of original soil suspension; N_i is the number of cells per 1 ml supernatant of the i-th wash, and n is the reciprocal of dilution rate. Ideally log n is 1.0 with our conditions.In the case of soils without sonic pretreatment, the values of log n were 0.009–0.018 for sulfate-reducing bacteria, indicating that almost constant numbers of sulfate-reducing bacteria were newly liberated by every wash, and 0.35–0.55 for aerobic bacteria, indicating that a direct wash-out of cells took place. With sonicated soils we obtained the values 0.26–0.38 and 0.39–0.55 respectively.Based on these results we conclude that sulfate-reducing bacteria were present in aggregates which were decomposed by sonic treatment, whereas aerobic bacteria were not.