Tissue Dry Weight Research Articles

Increased plant growth and copper uptake of host and non-host plants by metal-resistant and plant growth-promoting endophytic bacteria

ABSTRACTThe effects of inoculation with two metal-resistant and plant growth-promoting endophytic bacteria (Burkholderia sp. GL12 and Bacillus megaterium JL35) were evaluated on the plant growth and Cu uptake in their host Elsholtzia splendens and non-host Brassica napus plants grown in natural Cu-contaminated soil. The two strains showed a high level of ACC deaminase activities. In pot experiments, inoculation with strain GL12 significantly increased root and above-ground tissue dry weights of both plants, consequently increasing the total Cu uptake of E. splendens and Brassica napus by 132% and 48.2% respectively. Inoculation with strain JL35 was found to significantly increase not only the biomass of B. napus, consequently increasing the total Cu uptake of B. napus by 31.3%, but Cu concentration of E. splendens for above-ground tissues by 318% and roots by 69.7%, consequently increasing the total Cu uptake of E. splendens by 223%. The two strains could colonize the rhizosphere soils and root interiors of both plants. Notably, strain JL35 could colonize the shoot tissues and significantly increase the translocation factors and bioaccumulation factors of E. splendens. These results suggested that Burkholderia sp. GL12 and B. megaterium JL35 were valuable bacterial resource which had the potential in improving the efficiency of Cu phytoextraction by E. splendens and B. napus in a natural Cu-contaminated soil.

The effect of hatching time on the bioenergetics of northern pike (Esox lucius) larvae from a single egg batch during the endogenous feeding period.

Size, caloric value and chemical composition were measured separately in the progeny of two northern pike (Esox lucius) females at 3-day intervals during the endogenous feeding period from hatching to final yolk resorption. Tissue, yolk and entire larvae were analysed separately in three groups of larvae that hatched at different times (between 88 and 106 degree-days post-fertilization). An integrated approach with the Gompertz model was used to compute the yolk conversion efficiency and time to maximum tissue size in early, mid and late hatched larvae. At hatching, unresorbed yolk of early hatched larvae contained more energy (39.20 J) and more protein (0.99 mg) compared to the yolk of larvae that hatched later (38.13 J and 0.92 mg protein for late hatched larvae, p < 0.05). In contrast, a significant reduction in tissue weight (-0.7 mg DW) and protein content (-0.5 mg) was found in early hatched larvae compared to those which hatched later (p < 0.05). Between days 9 and 12 post-hatching (108 and 144 degree-days post-hatching), close to the final yolk resorption, late hatched larvae stopped growing and their tissue began to be resorbed. This tissue resorption time was delayed in early hatched larvae which presented at the end of the experiment a greater tissue weight than late hatched ones. Yolk conversion efficiency in term of energy from hatching to complete yolk resorption stage was significantly higher for early and mid hatched larvae (51%) compared to late hatched ones (44%) (p = 0.004). Furthermore, the time to maximum tissue size was found to be negatively related to hatching time which implies that early hatched larvae take longer time to switch from one developmental stage to the next. The maximum tissue dry weight and energy content were found to be reached at approximately the same age post-fertilization for both early hatched and late hatched larvae, suggesting that the principal steps in a fish's lifespan are better correlated with time of fertilization than hatching time.

Concentración y acumulación de nutrimentos en la biomasa aérea de plantaciones de teca de 3 a 18 años en la cuenca del Canal de Panamá

Se colectaron muestras de los compartimentos de la biomasa aérea (tronco, corteza, ramas primarias, ramas secundarias y hojas) de 16 árboles dominantes de plantaciones de teca cuyo rendimiento en volumen varió de 9,4 a 13,3 m3 ha-1.año-1, entre los 3 a 18 años de edad, respectivamente, en la cuenca del Canal de Panamá, con el propósito de determinar la concentración y acumulación de macronutrimentos (N, K, Ca, Mg, P y S) y micronutrimentos (Fe, Mn, Zn, Cu y B) por compartimento y por árbol, en suelos mayormente rojos, arcillosos y ácidos, clasificados como Ultisoles. Se ajustaron funciones de regresión para estimar la acumulación de cada nutrimento según la edad. La biomasa seca promedio del tronco de 3 a 18 años representó el 59,6% (C.V. 5%) de la biomasa seca total, mientras que las ramas primarias el 16,6%, la corteza el 9,4%, las hojas el 7,9% y las ramas secundarias el 6,5%. Los macronutrimentos de mayor concentración según el compartimento fueron el Ca (2,01%) en la corteza, y el N (1,98%) en las hojas. Los micronutrimentos de mayor concentración fueron el Fe (767 mg.kg-1), Mn (60 mg.kg-1) y Zn (50 mg.kg-1), todos en la corteza. La acumulación de macronutrimentos a la edad de 18 años fue de 15,9 kg.árbol-1 (7,3 kg de Ca; 3,9 kg de N; 2,6 kg de K; 1,0 kg de Mg; 0,7 kg de P y 0,4 kg de S) y la de micronutrimentos fue de 124 g (89 g de Fe; 18 g de Zn; 9 g de B; 5 g de Mn y 3 g de Cu).

Abstract 10402: Early Reduction of Myocardial Reactive Oxygen Species Production by Postconditioning in a Porcine Model of Cardiac Arrest and Resuscitation

Introduction: Ischemic (IPoC) and anesthetic postconditioning (APoC) during cardiopulmonary resuscitation (CPR) are effective interventions to improve hemodynamic outcome and survival in a porcine model of prolonged cardiac arrest. We hypothesized that both strategies decrease the myocardial production of reactive oxygen species (ROS) early during reperfusion. Methods: After 15 min of untreated ventricular fibrillation (VF), 22 pigs were randomized to receive mechanical CPR for 4 min without (control) or with IPoC (three 20-sec CPR interruptions) or APoC with low- (2 Vol%) or high-dose (4 Vol%) sevoflurane for 3 min before euthanasia and organ harvest. Left ventricular myocardial tissue was immediately frozen in liquid nitrogen and stored at -80°C until electroparamagnetic resonance (EPR) measurements were performed to quantify ROS. Data are mean±SEM. Statistics: ANOVA with SNK-post hoc testing, alpha = 0.05. Results: EPR spectral changes showed that high-dose APoC (10±1 arbitrary units) and IPoC (15±4) reduced reactive oxygen species normalized to dry tissue weight compared to untreated control animals (33±2); low-dose APoC (34±4) did not. Conclusions: Our data show that the cardio- and neuroprotective strategies of IPoC and APoC result in decreased myocardial ROS production that can be detected as early as 4 min after reintroduction of blood flow by mechanical CPR; the effective concentration of sevoflurane, however, has to be high enough to achieve APoC. Our findings underline the importance of early organ-protective strategies and contribute to our understanding of the mechanisms of these important clinical interventions to improve outcome and survival after cardiac arrest.

Breast Tissue Engineering

INTRODUCTION: Decellularization of tissues provides inductive extra-cellular matrices (ECM) for effective organ reconstruction: this promising approach has not been translated to breast reconstruction yet.1,2 We investigated the effectiveness of different decellularization protocols applied to porcine mammary glands with the purpose of developing an inductive biological matrix for prospective breast tissue engineering. METHODS: We cut porcine mammary glands into homogeneous samples (10x10x2cm) and processed these according to three different decellularization protocols (A, B, C). All protocols combined multiple chemical treatments (A: 0.02% trypsin, 0.05% ethylenediaminetetraacetic acid-EDTA, 3% Triton X-100, 4% deoxycholic acid; B: collagenase 3mg/g, 0.02% trypsin, 0.05% EDTA, 10U/mL, 10U/mL lipase; C: collagenase 3mg/g, 0.05% EDTA, 4% sodium deoxycholate, 1% sodium dodecyl sulfate, 0.9% NaCl in TRIS-HCl containing protease inhibitors). We analyzed processed specimens by macroscopic (morphologic) and microscopic methods (Hematoxylin and Eosin staining, Immuno-fluorescent labeling with 4′,6-diamidino-2-phenylindole-DAPI, quantitative measurement of DNA and DNA fragment size) to assess quality of decellularization and structural preservation of the matrix. RESULTS: Harvested mammary glands could be molded to required shape; adjacent glands could be harvested together (up to 700grams). Maximal size of obtainable glands based on a single blood supply varied (average: 20x40x3cm). Blood supply was based on a single reliable vascular pedicle, potentially suitable for microsurgical anastomosis in vivo. Decellularization protocols had variable effectiveness: all samples showed macroscopic evidence of decellularization preserving original morphology at gross examination. DAPI, quantitative measurement of DNA (below 50 ng/mg dry tissue weight) and of DNA fragment size (below 200 base-pairs) showed effective reduction of immunogenic components in each protocol. At histological analysis (Hematoxylin and Eosin) protocol A provided a morphology more closely resembling native architecture of ECM and a more effective preservation of the vascular and ductal networks. Protocols B and C, instead, slightly damaged and altered histological structure of the matrix. CONCLUSIONS: Decellularization of porcine mammary tissue represents a novel and reliable preliminary approach to develop a bio-inductive matrix for potential subsequent breast tissue engineering.

Recovery of wild Pacific oyster, Crassostrea gigas in terms of reproduction and gametogenesis two-years after the Hebei Spirit Oil Spill Accident off the West Coast of Korea

The Hebei Spirit oil spill in December 2007 at Taean off the west coast of Korea was the largest oil tanker accident in Korea. However, the impact of the spill on physiology of benthic animals remains largely unknown. Two-years after the accident, we compared reproductive effort and annual gametogenesis of the wild Pacific oyster Crassostrea gigas, residing at oil spill site with a control oyster population in Incheon Bay, North-West coast of Korea. Results showed that the oyster sampled from the oil spill site showed a significantly higher (279.0mgstandard animal−1, P<0.05) growth by tissue dry weight to that of the control population (228.0mgstandard animal−1, P<0.05). Histology revealed that there was no significant difference in the annual gametogenic pattern between the two populations, and most of the females of both populations spawned between August and September. During spawning season, egg mass of oysters determined using enzyme-linked immunosorbant assay (ELISA) in the oil spill area was significantly higher (136.3mgstandard animal−1, P<0.05) than the control population (120.5mgstandard animal−1, P<0.05). The tissue protein level in the oysters at the contaminated area was significantly higher (102.6mgstandard animal−1, P<0.05) than the level measured from the control oysters (81.4mgstandard animal−1, P<0.05). The observed better biological performances of oysters at the contaminated site suggested their recovery of the physiological status to normal level after two years of the oil spill accident.

Metal bioaccumulation pattern by Cotylorhiza tuberculata (Cnidaria, Scyphozoa) in the Mar Menor coastal lagoon (SE Spain).

Coastal lagoons are ecosystems highly vulnerable to human impacts because of their situation between terrestrial and marine environment. Mar Menor coastal lagoon is one of the largest lagoons of the Mediterranean Sea, placed in SE Spain and subjected to major human impacts, in particular the mining of metal sulphides. As a consequence, metal concentration in water column and sediments of this ecosystem is usually higher than in other areas. For monitoring ecosystem health, the present study has assessed the ability of Cotylorhiza tuberculata for bioaccumulating metals from sea water. Up to 65 individuals were sampled at 8 different sampling stations during the summer of 2012. Although the concentration values for different elements considered were moderate (Pb: 0.04-29.50 ppm, Zn: 2.27-93.44 ppm, Cd: 0-0.67 ppm, As: 0.56-130.31 ppm) by dry weight of the jellyfish tissues (bell and oral arms combined), bioconcentration levels in relation to seawater metal concentration were extremely high. In any case, the use or disposal of these organisms should consider their metal content because of their potential environmental and health implications.

Elastin governs the mechanical response of medial collateral ligament under shear and transverse tensile loading

Elastin is a highly extensible structural protein network that provides near-elastic resistance to deformation in biological tissues. In ligament, elastin is localized between and along the collagen fibers and fascicles. When ligament is stretched along the primary collagen axis, elastin supports a relatively high percentage of load. We hypothesized that elastin may also provide significant load support under elongation transverse to the primary collagen axis and shear along the collagen axis. Quasi-static transverse tensile and shear material tests were performed to quantify the mechanical contributions of elastin during deformation of porcine medial collateral ligament. Dose response studies were conducted to determine the level of elastase enzymatic degradation required to produce a maximal change in the mechanical response. Maximal changes in peak stress occurred after 3h of treatment with 2U/ml porcine pancreatic elastase. Elastin degradation resulted in a 60–70% reduction in peak stress and a 2–3× reduction in modulus for both test protocols. These results demonstrate that elastin provides significant resistance to elongation transverse to the collagen axis and shear along the collagen axis while only constituting 4% of the tissue dry weight. The magnitudes of the elastin contribution to peak transverse and shear stress were approximately 0.03MPa, as compared to 2MPa for axial tensile tests, suggesting that elastin provides a highly anisotropic contribution to the mechanical response of ligament and is the dominant structural protein resisting transverse and shear deformation of the tissue.

Effect of Sulphur dioxide on growth, Chlorophyll and sulphur contents of Pomegranate

The direct toxic effect of atmospheric pollutant such as sulphur dioxide on plants has been well documented. It is essentially a potent phytotoxic gas and its toxicity to plant is manifested in typical chronic or acute foliar symptom injury. The mode and extent of damage caused by this pollutant to pomegranate has not been precisely and systematically studied. Under such circumstances, the present investigation was undertaken under simulating condition to find out the possible extent of adaptability of pomegranate in SO2 emission of our state. The effect of varying levels of sulphur dioxide (0.25, 0.5 and 1.0ppm) fumigated for 1, 2 and 3h under simulated conditions on pomegranate revealed that the important traits like leaf number, leaf area, fresh weight, dry weight and chlorophyll content in leaves were adversely affected by SO2 level. SO2 1.0ppm with 3h exposure found to be more harmful. However, no significant variation was seen amongst the treatments in respect of tissue fresh and dry weight when compared with that of control (ambient SO2). On the other hand, sulphur content in tissues increase progressively with increasing levels of SO2 and time of fumigation and the variation observed within treatments was significant to each other. It is suggested that the lowest concentration of SO2 (0.25 ppm) used in this study is more than sufficient to bring about a significant changes in most of the parameters studied. Tropical Agricultural Research and Extension 16(1): 2013: page 21-24

Protective effect of estrogen on acute lung injury after hemorrhagic shock in pregnant rabbit

The paper is an attentative effort to evaluate the reaction and mechanism of estrogen on pregnant rabbits with acute lung injury caused by hemorrhagic shock. Sixty pregnant New Zealand white rabbits were randomly divided into 6 groups, with 10 rabbits in each group, namely normal control group (NG group, with anesthesia only), estrogen group (E(2)G group, with additional estrogen injection at 60 min) and the other four hemorrhagic shock groups underwent hemorrhagic shock (i.e. E(2)SG, FSG, SBSG, E(2)SBSG group; mean blood pressure- 40 mmHg (1 mmHg = 0.133 kPa) by phlebotomy for 15 min. After maintenance of the pressure for 45 min, the rabbits were treated with E(2) (0.37 mg/kg), fructose injection (5%, 2 ml/kg), the p38 mitogen-activated protein kinases (p38MAPK) inhibitor SB-203580 (2 mg/kg) or E(2) plus SB-203580. Tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) were measured at different time points (0 min, 60 min, 80 min and 260 min), lung tissue methane dicarboxylic aldehyde (MDA) level, lung tissue myeloperoxidase (MOP), superoxide dismutase (SOD) activity, lung tissue dry weight/wet weight (DW/WW) value were measured after the experiment was finished, pulmonary pathology of the rabbits was observed. (1) Serum TNF-α level of NG group and E(2)SG group were not significantly different compared with the other four groups at the 0 min and 60 min. At 80 min and 260 min of experiment, serum TNF-α level of all the four shock groups were increased, E(2)SG group [(172.4 ± 16.0) and (216.7 ± 18.6) ng/L], FSG group [(171.6 ± 9.1) and (263.9 ± 7.8) ng/L], SBSG group [(172.8 ± 7.2) and (300.6 ± 4.8) ng/L], E(2)SBSG group [(167.9 ± 4.8 ) and (261.8 ± 9.6) ng/L], and significantly higher than NG group and E(2)G group, separately (P < 0.05). (2) Serum IL-6 level of NG group and E(2)SG group were not significantly different compared with the other four groups at the 0 min, 60 min and 80 min. At 260 min, the serum IL-6 level [(98.3 ± 0.9) and (110.4 ± 1.8) ng/L; (120.9 ± 2.3) and (109.8 ± 2.6) ng/L] of the four shock groups (E(2)SG, FSG, SBSG, E(2)SBSG group) were significantly higher than NG group and E(2)G group (P < 0.05). (3) Lung tissue MDA level [(2.20 ± 0.12), (2.57 ± 0.11), (3.17 ± 0.08), (2.75 ± 1.09) nmol/mg] and MPO activity [(4.45 ± 0.25), (6.65 ± 0.56), (9.55 ± 0.30), (6.78 ± 0.11) U/mg] of the four shock groups (E(2)SG, FSG, SBSG, E(2)SBSG group) were higher than NG group and E(2)G group (P < 0.05). (4) Lung tissue SOD activity [(51.8 ± 1.8), (40.2 ± 1.5), (30.0 ± 1.7), (41.2 ± 2.0) U/mg] was significantly higher in the four shock groups (E(2)SG, FSG, SBSG, E(2)SBSG group) compared with NG group and E(2)G group (P < 0.05). (5) Lung tissue DW/WW value (0.143 ± 0.008, 0.127 ± 0.008, 0.109 ± 0.006, 0.125 ± 0.008) was significantly lower in the four shock groups (E(2)SG, FSG, SBSG, E(2)SBSG group) compared with NG group and E(2)G group (P < 0.05). (6) Lung tissue of the rabbits in NG group and E(2)G group is basically normal without obvious pathology changes. Lung tissue pathological damage of rabbits was observed in the four shock groups, and the pathological damage of rabbits in SBSG group was most serious. Estrogen can reduce acute lung injury of pregnant rabbits with hemorrhagic shock, the p38MAPK pathway plays a critical role in mediating the salutary effects of E(2) on shock-induced acute lung injury.

Elemental diet moderates 5-fluorouracil-induced gastrointestinal mucositis through mucus barrier alteration.

There are reports that elemental diet (ED) ameliorates oral mucositis caused by antineoplastic chemotherapy. Although this effectiveness may be partly due to high nutrient absorption, the effects of chemotherapy on mucosal defense mechanisms remain unclear. We investigated the effects of oral supplementation with ED on mucin in 5-fluorouracil (5-FU)-induced intestinal mucositis. 5-FU was administered to rats orally once daily, and ED was supplied orally twice daily for 5 days. The severity of mucositis was assessed by length, dry tissue weight, and villus height of the intestinal tract. Using anti-mucin monoclonal antibody, we compared the immunoreactivity in the gastrointestinal (GI) tract and mucin content by histological and biochemical examinations. Oral supplementation with ED reduced histological damage and loss of length, dry tissue weight, and villus height induced by 5-FU administration. ED markedly altered PGM34 antibody immunoreactivity and mucin contents in the small intestine of rats with 5-FU-induced mucositis. ED may possibly be more effective for the prevention of antineoplastic chemotherapy-induced mucositis through the activation of GI mucus cells.

Speciation of Cu and Zn in Two Colored Oyster Species Determined by X-ray Absorption Spectroscopy.

In oysters, Cu and Zn concentration can reach extraordinarily high (1-2% of tissue dry weights), leading to intense green or blue colors in oyster tissues. It is thus puzzling how oysters detoxify the excessively accumulated metals. Here, we used X-ray absorption spectroscopy to examine the Cu and Zn speciation in two "colored" oysters (Crassostrea hongkongensis and Crassostrea sikamea) collected from a severely metal-contaminated estuary. In contaminated oysters, we found a much higher proportion of tissue Cu and Zn as oxygen- or nitrogen-bonded species, contrasting to the sulfur-bonded (thiolate) species in normal oysters. Speciation of Cu and Zn in mantle was similar to that in gills, both of which were different from that in the digestive gland. In C. sikamea, the difference of metal speciation between normal and contaminated individuals was of similar pattern but less pronounced than that in C. hongkongensis. In normal oysters, Cu existed mainly as Cu(I) bound to sulfur, whereas in contaminated oysters mainly as Cu(II) bound to oxygen or nitrogen. Our study provided direct and semiquantitative information on the changes of metal speciation in contaminated oysters, indicating that oysters could efficiently detoxify the excessively accumulated Cu and Zn by storing them in oxygen- and nitrogen-bonded complexes in metal-rich environments.

High expression of consensus dengue virus envelope glycoprotein domain III using a viral expression system in tobacco

Although plant-based vaccines have many advantages, their use is limited by low expression of antigen genes in transgenic plants, which results in low immune responses and immune tolerance. To overcome this problem, Nicotiana benthamiana was used to produce the consensus domain III of dengue virus envelope glycoprotein (E) via agroinfiltration with a plant virus-based expression system. The binding of E glycoprotein to a receptor is important for dengue virus entry into host cells and results in human disease. Consensus domain III of dengue virus E glycoprotein (cEDIII) is immunogenic and can elicit neutralizing antibodies against all four serotypes of dengue virus. A DNA fragment encoding cEDIII and M cell-targeting ligand fused to cEDIII (cEDIII-Co1) were constructed in a viral vector and introduced into tobacco plant cells by Agrobacterium-mediated infiltration. The cEDIII and cEDIII-Co1 fusion proteins were detected in protein extracts from agroinfiltrated leaves by Western blot analysis. The plant-produced cEDIII and cEDIII-Co1 fusion proteins composed 5.2 and 4.8 mg/g of dry weight of leaf tissues, respectively. These results suggest that the high expression of dengue virus cEDIII in plants with a plant virus-based expression system can overcome the low expression level to improve the feasibility of plant-based vaccines.

Biochar and mycorrhizal fungi influence on nutrient uptake by two pasture species in new zealand

The symbiotic relationship between plants and mycorrhizal fungi can play an important role in enhancing nutrient uptake from the soil. Many New Zealand farm soils have elevated levels of phosphorus because of regular, long term, application of phosphate fertiliser. Much of this phosphate is not available to plants. This study aimed to investigate the effect of biochar on mycorrhizal growth and subsequent phosphorus uptake by white clover and ryegrass. The experiment was conducted in a 3×2×2 factorial design, including two biochar produced from pine at different final pyrolysis temperature (350 and 550°C), mycorrhizal inoculation (Glomus sp. arbuscular mycorrhiza) and phosphate rock, respectively. The soil sample was provided from the 10cm surface horizon of an Egmont black loam. The pots were filled with the soil sample mixed with biochar applied at 10 tha -1 .Phosphate rock was applied at a rate of 70 kg ha -1 . The seeds were inoculated by Glomus sp. arbuscular mycorrhizae before sowing. The ryegrass also contained the endophyte, AR37. Dry weight, phosphorus and nitrogen concentrations of plant tissue were measured68 days after sowing. There was an increase in both phosphorus uptake and dry weight in plants grown with the high temperature biochar (B550). There was significant increase in phosphorus uptake and herbage yield in clover plants if inoculated by mycorrhizal fungi. The results demonstrated that biochar have the potential to affect the nutrients in soil and microbial activity.

Mussels (Mytilus galloprovincialis) as a bio-indicator species in radioactivity monitoring of Eastern Adriatic coastal waters

Croatian Adriatic coastal waters are systematically monitored within the Mediterranean Mussel Watch Project using mussels (Mytilus galloprovincialis) as a bio-indicator species. The study includes determination of naturally occurring (7Be, 40K, 232Th, 226Ra and 238U), as well as anthropogenic 137Cs radionuclides. Activity concentrations in dry weight of mussels' soft tissue along the Croatian Adriatic coast are presented, with spatial and seasonal variations given and discussed. Samples were collected in spring and autumn for the period between 2009 and 2013. Radionuclides were determined by gamma-ray spectrometry. Activity concentrations of 7Be were the highest in spring periods, especially in the areas with significant fresh water discharges. Activity concentrations of 40K did not vary significantly with season or location. 137Cs activities were low, while 232Th, 226Ra and 238U activities were mostly below the detection limit of performed gamma-spectrometric measurement.

Temporal trends in condition and reproduction of quagga mussels (Dreissena rostriformis bugensis) in southern Lake Michigan

Currently little is known about the condition and spawning patterns of quagga mussels (Dreissena rostriformis bugensis) in deeper, consistently cold regions of the Great Lakes. This lack of information limits our ability to predict the future expansion of D. r. bugensis in the offshore regions of the Great Lakes and other large, deep lakes. We collected quagga mussels on a monthly basis in 2013 (April–September) at three established sites along a depth transect (25, 45, and 93 m) in southern Lake Michigan and calculated a condition index (CI), a ratio of dry soft tissue weight to internal shell capacity, to assess condition, and a gametogenic index to assess reproductive activity. We also measured size–frequency, density, and biomass in March, July, and October. Condition was consistently highest at 25 m, population biomass and average shell length were highest at 45 m, and density was highest at 93 m. At all three depths, CI decreased with increasing shell length suggesting that food availability may be limiting for larger individuals. Mussels at 45 m spawned earliest with over 50% spent by July while mussels at 93 m began spawning in August. Mussels at 25 m had not yet spawned by September. Long-term trends in density indicate that D. r. bugensis populations continued to expand at the 93 m site but may be stabilizing at 25 m and 45 m. Consistent with density trends, CI at 25 m and 45 m was lower than in 2004 and 2008.

Does the Animal Origin Influence the Calcification of Xenograft Tissue Heart Valve Substitutes? Comparison between Bovine and Camel Pericardium in a Subcutaneous Rat Model

Objective: To validate the hypothesis that camel pericardium could be more protected than bovine pericardium against calcification process according to the huge difference in their respective lifestyle and lifetime. Methods: Glutaraldehyde (GA) fixed bovine and camel pericardium samples (BP and CP respectively) were both implanted in 30 New Zealand white rats (2 BP and 2 CP matched specimens in each animal) and explanted after 60 days. Unimplanted GA-fixed samples of both species served as control. Matched implanted samples and unimplanted samples were randomly submitted to elemental analysis by spectroscopy, phospholipid extraction, macroscopic and X-ray examination and histology. Results: At 60 days, calcium and phosphorus content were respectively 9.54% ± 3.1% and 4.79% ± 1.4% of tissue dry weight in BP, and 12.52% ± 2.7% and 6.14% ± 1.3% of tissue dry weight in CP (ns). In X-ray analysis, the calcification score was 1.28 ± 0.45 and 2.14 ± 0.98 in BP and CP samples respectively without significant difference (p < 0.08). In histology, calcifications were lower in BP than in CP: 1.37 ± 0.85 vs 2.28 ± 0.83 (ns); collagen fibers were better conserved in BP than in CP: 2.4 ± 0.48 vs 1.87 ± 0.78 (ns), and less disoriented: 25% vs 62% (ns). In unimplanted samples, there was a higher but not significant rate of extracted lipids in CP: 5.7 ± 1.8 vs 9.5 ± 3.8 nanomoles in PS fraction and 11.3 ± 3.7 vs 19 ± 7.7 nanomoles in total fatty acids, in BP and CP samples respectively. All results were in conjunction and demonstrated a higher but not significant rate of mineralization in camel pericardium after implantation, which could be related to a higher but not significant basic rate of phospholipid and fatty acids. Conclusion: This experiment study in a subcutaneous rat model has failed to valid our hypothesis. Because the differences observed between bovine and camel pericardium did not reach the significance, at the best, there is no difference between both species and at the worst, camel pericardium has a higher rate of the phosphatidylserine fraction of phospholipid, and is more sensitive and prompt to calcification.

Genotypic Variation for Tolerance to Transient Drought During the Reproductive Phase of Brassica rapa

AbstractBrassica rapa L. is a genetically diverse parent species of the allotetraploid species, oilseed rape (B. napus) and a potential source of drought tolerance for B. napus. We examined the effect of a 13‐day drought stress period during the early reproductive phase, relative to a well‐watered (WW) control, on subsequent growth and development in nine accessions of B. rapa and one accession of Brassica juncea selected for their wide morphological and genetic diversity. We measured leaf water potential, stomatal conductance, water use, and leaf and bud temperatures during the stress period and aboveground dry weight of total biomass at maturity. Dry weight of seeds and reproductive tissue were not useful measures of drought tolerance due to self‐incompatibility in B. rapa. The relative total biomass (used as the measure of drought tolerance in this study) of the 10 accessions exposed to drought stress ranged from 47 % to 117 % of the WW treatment and was negatively correlated with leaf‐to‐air and bud‐to‐air temperature difference when averaged across the 13‐day stress period. Two wild‐type (B. rapa ssp. sylvestris) accessions had higher relative total and non‐reproductive biomass at maturity and cooler leaves and buds than other types. We conclude that considerable genotypic variation for drought tolerance exists in B. rapa and cooler leaves and buds during a transient drought stress in the early reproductive phase may be a useful screening tool for drought tolerance.

Effects of temperature and body size on the physiological energetics of the stalked sea squirt Styela clava

An assessment of the patterns of thermal acclimation of physiological processes of the stalked sea squirt Styela clava is needed to further understand growth patterns associated with large seasonal fluctuations in ambient temperature. The effects of different exposure temperatures on physiological processes of S. clava were measured at 5, 10, 15, 20, and 25°C. The impact of temperature on energy balance at a whole organism level was then assessed by scope for growth (SFG) and net growth efficiency (K2) measures. Physiological rates of S. clava were well correlated with its dry tissue weight (DW). Positive allometry with DW indicated that all physiological rates investigated were generally higher in the larger individuals regardless of temperature. Some allometric equations (e.g., feces production rate vs. DW and respiration rate vs. DW) exhibited identical estimates of exponents, enabling accurate comparisons of the rates across temperatures. In contrast, disparities across temperatures of the values for the weight exponent were detected in other allometric equations, revealing that thermal effects on these rates have different degrees for large and small individuals. The SFG value in S. clava of different sizes was similar at lower temperatures (5–10°C), peaking at 15°C. The SFG was positive with a relatively constant K2 in this temperature range. This positive energy balance reflects the reduction in metabolic costs at lower temperatures. In contrast, increased metabolic costs at higher temperatures (20–25°C) resulted in lowered SFG and K2 values, indicating that the feeding rate did not increase as greatly in compensation for the increased metabolic costs at higher temperatures. The lowered absorption at 25°C (compared with 20°C) resulted in negative SFG and K2 values. Finally, our results confirm that the absence of compensatory adjustment to warmer conditions leads to energetic disruption at a whole organism level at such temperatures.

Effect of bacterial treatment on Cr(VI) remediation from soil and subsequent plantation of Pisum sativum

In order to evaluate the bioremediation efficiency of Cr(VI) contaminated soil, it is very important to measure a level of metal toxicity in edible plant tissues to make sure about their consumption by animals or humans. In the present study, artificially contaminated soil with Cr(VI) as high as 100mgkg−1 were treated based on microbially induced calcite precipitation (MICP). The urease producing Bacillus cereus YR5 was employed for the treatment of soil, which resulted in remarkably lower Cr(VI) in the bio-available soil fraction in one month. After the bioremediation, Pisum sativum seeds were planted in the soil and harvested after 60 days. Compared to Cr(VI) content of 7.5–18mgkg−1 in the dry weight of different tissues of P. sativum grown in contaminated soil, bioremediation resulted in Cr(VI) content of only 0.34–0.65mgkg−1 in its root, stem and leaf. Further, EDS analysis revealed sharp peak of Cr in stems of P. sativum grown in contaminated soil, which were not remarkable when grown in treated soil. The results revealed MICP as highly efficient technology for heavy metal remediation and plants grown in such treated soil will be safe for consumption purposes.