Association of Pb,Cd, and Se Concentrations and Oxidative Damage-Related Markers in Different Grades of Prostate Carcinoma

Prostate cancer is known to be affected by the heavy metal levels and oxidative damage of the body, yet there are very few studies which look into the way it occurs. The aim of this study was to determine whether blood and tissue lead (Pb), cadmium (Cd), and selenium (Se) levels are associated with oxidative damage in the context of prostate cancer progression and development. Seventy-nine patients comprising 25 patients with benign prostatic hypertrophy (BPH), 23 patients with malignant prostatic carcinoma (malign Ca), 16 patients with low-grade prostatic intraepithelial neoplasia (LGPIN), and 15 patients with high-grade prostatic intraepithelial neoplasia (HGPIN) diagnosed on the basis of their clinical profile, transrectal ultrasonography, and histopathology were included in this study. Cd and Pb levels in whole blood were found to be increased in patients with HGPIN compared with the BPH group; also, the levels of Cd in whole blood and tissue were found to be increasing in patients with malign Ca, unlike BPH patients. Moreover, the levels of malondialdehyde (MDA) in plasma and tissue were significantly increased in malign Ca, LGPIN, and HGPIN than those in BPH. However, the levels of tissue Pb were found to be decreasing in BPH, unlike the malign Ca and HGPIN patients, and the levels of tissue protein carbonyls in malign Ca were significantly lower than those in HGPIN. The levels of tissue reduced glutathione (GSH) in malign Ca were significantly lower than those in BPH. Additionally, the levels of Se in serum and tissue in LGPIN were significantly lower than those in BPH. The serum Se levels in HGPIN were also significantly lower than those in BPH and malign Ca groups. Furthermore, the concentrations of serum Se in LGPIN were significantly lower than those in malign Ca. From the Pearson correlation analysis, there were significant positive correlations between tissue Cd and MDA levels in malign Ca, LGPIN, and HGPIN and between the tissue Pb and tissue MDA and protein carbonyl levels in malign Ca. Blood Pb and tissue Pb were also significantly positively correlated with plasma MDA and protein carbonyl levels in malign Ca. In addition, blood Pb was significantly positively correlated with tissue MDA and protein carbonyl levels in malign Ca, and a significant positive correlation was also found between blood Cd and plasma protein carbonyls and tissue MDA in LGPIN. We observed that altered prooxidant–antioxidant balance and heavy metal levels may lead to an increase in oxidative damage and may consequently play an important role in prostate carcinogenesis. These findings indicate that changes in the levels of Pb, Cd, Se, MDA, protein carbonyls, and GSH in the blood and/or tissue are related to the prostatic carcinoma development and progression, although triggering one of the mentioned changes is unknown; therefore, further study is required to determine the exact steps of the process and clarify the roles of different substances in order to obtain a more detailed explanation of the phenomenon.     

Oncogenic transformation of human benign prostate hyperplasia with chronic cadmium exposure

Experimentally, it has been proved that cadmium served as an effective carcinogen and able to induce tumors in rodents in a dose-specific manner. However, systemic evaluation of cadmium exposure for the transformation of prostatic hyperplasia into prostate cancer (PCa) is still unclear. In the present study, an attempt has been made to establish cadmium-induced human prostate carcinogenesis using an in vitro model of BPH cells. Wide range of cadmium concentrations, i.e., 1 nM, 10 nM, 100 nM and 1μM, were chronically exposed to the human BPH cells for transformation into PCa and monitored using cell and molecular biology approaches. After eight weeks of exposure, the cells showed subtle morphological changes and shifts of cell cycle in the G2M phase. Significant increase in expression of prostatic genes AR, PSA, ER-β, and 5αR with increased nuclear localization of AR and pluripotency markers Cmyc, Klf4 indicated the carcinogenic effect of Cd. Further, the BPH cells exposed to Cd showed a substantial increase in the secretion of MMP-2 and MMP-9, influencing migratory potential of the cells along with decreased expression of the p63 protein which further strengthen the progression towards carcinogenesis and aggressive tumor studies. Data from the present study state that Cd exhibited marked invasiveness in BPH cells. These observations established a connecting link of BPH towards PCa pathogenesis. Further, the study will also help in investigating the intricate pathways involved in cancer progression.     

An evaluation of phycoremediation potential of cyanobacterium Nostoc muscorum: characterization of heavy metal removal efficiency

The present study relates to the use of cyanobacterium Nostoc muscorum as a model system for removal of heavy metals such as Pb and Cd from aquatic systems. The effects of various physicochemical factors on the surface binding and intracellular uptake of Pb and Cd were studied to optimize the metal removal efficiency of the living cells of N. muscorum. Results demonstrated that a significant proportion of Pb and Cd removal was mediated by surface binding of metals (85 % Pb and 79 % Cd), rather than by intracellular accumulation (5 % Pb and 4 % Cd) at the optimum level of cyanobacterial biomass (2.8 g L^?1), metal concentration (80 μg mL^?1), pH (pH 5.0–6.0), time (15–30 min), and temperature (30–40 °C). N. muscorum has maximum amounts of metal removal (q _max) capacity of 833 and 666.7 mg g^?1 protein for Pb and Cd, respectively. The kinetic parameters of metal binding revealed that adsorption of Pb and Cd by N. muscorum followed pseudo-second-order kinetics, and the adsorption behavior was better explained by both Langmuir and Freundlich isotherm models. The surface binding of both the metals was apparently facilitated by the carboxylic, hydroxyl, and amino groups as evident from Fourier transform infrared spectra.     

Statistical Evaluation of Trace Metals,TSH and T<Subscript>4</Subscript> in Blood Serum of Thyroid Disease Patients in Comparison with Controls

The present study is based on the measurement of concentrations of selected trace metals (Fe, Zn, Cu, Co, Mn, Ni, Cr, Cd and Pb) and thyroid hormones (TSH and T₄) in blood serum of hypothyroid and hyperthyroid patients in comparison with healthy donors/controls in order to establish the imbalances of the trace metals in diseased subjects. The serum samples were digested in HNO₃-HClO₄ mixture and quantification of the metals was performed by flame atomic absorption spectrometry. Average levels of Fe, Ni, Cu, Cr, Pb and TSH were found to be significantly higher (p < 0.05) in the serum of hypothyroid patients compared with other donor categories, while mean concentrations of Mn, Cd and T₄ were significantly elevated in the serum of hyperthyroid patients compared with other donor groups (p < 0.05). The correlation pattern of trace metals in the serum of patient groups revealed significantly different mutual associations compared with the controls. PCA and CA pointed out the interferences of the toxic metals with essential metals in the serum of both patient groups compared with the controls. Most of the metals exhibited noticeable disparities in their concentrations based on gender, food habits and tobacco use for all donor groups. Thus, the pathogenesis of thyroid diseases is significantly affecting the essential trace and toxic metals balance in both patients groups.     

Association of mycoplasma with prostate cancer: A systematic review and meta-analysis

Mycoplasmas are emerging sexually transmitted pathogens usually associated with male urinary tract infection, non-gonococcal urethritis (NGU), infertility, and prostate cancer. In this study, we review the evidence linking mycoplasma infection and prostate cancer. We conducted a systematic review and meta-analysis based on PRISMA guidelines. Four electronic databases were reviewed through January 31, 2021. Studies were eligible for inclusion if odds ratio for prevalence or incidence of colonization and/or infection were provided or calculable. All included studies were evaluated independently by three reviewers. The quality of the included studies was assessed using the Newcastle-Ottawa Scale for Case-Control Studies. Statistical analysis was done using Review Manager Version 5.4. A total of 183/744 (24.6 %) patients with prostate cancer compared to 87/495 (17.58 %) patients with benign prostatic hyperplasia (BPH) tested positive for Mycoplasma spp., while 86/666 (12.91 %) and 11/388 (2.84 %) prostate cancer patients and BPH patients, respectively, had Ureaplasma spp. infections. This meta-analysis showed that prostate cancer patients had 2.24 times higher odds (p = 0.0005) of being colonized with any species of Mycoplasma spp. and 3.6 times increased odds (p = 0.008) of being colonized with any species of Ureaplasma spp. In conclusion, patients with prostate cancer were more likely to be colonized with Mycoplasma spp. or Ureaplasma spp. compared to patients with BPH, which highlights the potential association between chronic infection and cancer. However, more studies are needed to determine the specific role that mycoplasma plays in the pathogenesis of prostate cancer.     

Simple Modification of the Bladder Outlet Obstruction Index for Better Prediction of Endoscopically-Proven Prostatic Obstruction: A Preliminary Study

Purpose

The bladder outlet obstruction index (BOOI), also known as the Abrams-Griffiths (AG) number, is the most widely used index for predicting BOO. However, the obstructed prostatic urethra determined by the BOOI is often inconsistent with endoscopically-proven obstruction. We assessed abdominal straining pattern as a novel parameter for improving the prediction of BOO.

Materials and Methods

We retrospectively reviewed the pressure-flow studies (PFS) and cystourethroscopy in 176 BPH/LUTS patients who were unresponsive to medical therapy. During PFS, some groups of patients tried to urinate with abdominal straining, which can increases intravesical pressure and underestimate BOOI theoretically. Accordingly, the modified BOOI was defined as (P_detQ_max+ΔP_abd)-2Q_max.

Results

Ultimately, 130 patients were eligible for the analysis. In PFS, ΔP_abd (P_abdQ_max-initial P_abd) was 11.81±13.04 cmH₂O, and it was 0–9 cmH₂O in 75 (57.7%), 10–19 cmH₂O in 23 (17.7%) and ≥20 cmH₂O in 32 (24.6%) patients. An endoscopically obstructed prostatic urethra in 92 patients was correctly determined in 47 patients (51.1%) by the original BOOI versus 72 patients (78.3%) based on the modified BOOI. Meanwhile, an “unobstructed” urethra according to the original BOOI was present in 11 patients (12.0%), whereas according to the modified BOOI, only 2 (2.1%) would be labeled as “unobstructed”. In receiver operating characteristic curves, the area under the curve was 0.906 using the modified BOOI number versus 0.849 in the original BOOI (p<0.05).

Conclusions

The change in abdominal pressure was correlated with endoscopically-proven obstruction. Our simple modification of the BOOI on the basis of this finding better predicted bladder outlet obstruction and, therefore, should be considered when evaluating BOO in patients with LUTS/BPH.     

Prostate Tissue Metal Levels and Prostate Cancer Recurrence in Smokers

Although smoking is not associated with prostate cancer risk overall, smoking is associated with prostate cancer recurrence and mortality. Increased cadmium (Cd) exposure from smoking may play a role in progression of the disease. In this study, inductively coupled plasma mass spectrometry was used to determine Cd, arsenic (As), lead (Pb), and zinc (Zn) levels in formalin-fixed paraffin embedded tumor and tumor-adjacent non-neoplastic tissue of never- and ever-smokers with prostate cancer. In smokers, metal levels were also evaluated with regard to biochemical and distant recurrence of disease. Smokers (N?=?25) had significantly higher Cd (median ppb, p?=?0.03) and lower Zn (p?=?0.002) in non-neoplastic tissue than never-smokers (N?=?21). Metal levels were not significantly different in tumor tissue of smokers and non-smokers. Among smokers, Cd level did not differ by recurrence status. However, the ratio of Cd ppb to Pb ppb was significantly higher in both tumor and adjacent tissue of cases with distant recurrence when compared with cases without distant recurrence (tumor tissue Cd/Pb, 6.36 vs. 1.19, p?=?0.009, adjacent non-neoplastic tissue Cd/Pb, 6.36 vs. 1.02, p?=?0.038). Tissue Zn levels were also higher in smokers with distant recurrence (tumor, p?=?0.039 and adjacent non-neoplastic, p?=?0.028). These initial findings suggest that prostate tissue metal levels may differ in smokers with and without recurrence. If these findings are confirmed in larger studies, additional work will be needed to determine whether variations in metal levels are drivers of disease progression or are simply passengers of the disease process.     

Acetyl-l-Carnitine and Oxfenicine on Cardiac Pumping Mechanics in Streptozotocin-Induced Diabetes in Male Wistar Rats

Introduction

In the treatment of patients with diabetes, one objective is an improvement of cardiac metabolism to alleviate the left ventricular (LV) function. For this study, we compared the effects of acetyl-l-carnitine (one of the carnitine derivatives) and of oxfenicine (a carnitine palmitoyltransferase-1 inhibitor) on cardiac pumping mechanics in streptozotocin-induced diabetes in male Wistar rats, with a particular focus on the pressure-flow-volume relationship.

Methods

Diabetes was induced by a single tail vein injection of 55 mg kg⁻¹ streptozotocin. The diabetic animals were treated on a daily basis with either acetyl-L-carnitine (1 g L⁻¹ in drinking water) or oxfenicine (150 mg kg⁻¹ by oral gavage) for 8 wk. They were also compared with untreated age-matched diabetic controls. LV pressure and ascending aortic flow signals were recorded to calculate the maximal systolic elastance (E _max) and the theoretical maximum flow (Q _max). Physically, E _max reflects the contractility of the myocardium as an intact heart, whereas Q _max has an inverse relationship with the LV internal resistance.

Results

When comparing the diabetic rats with their age-matched controls, the cardiodynamic condition was characterized by a decline in E _max associated with the unaltered Q _max. Acetyl-l-carnitine (but not oxfenicine) had reduced cardiac levels of malondialdehyde in these insulin-deficient animals. However, treating with acetyl-l-carnitine or oxfenicine resulted in an increase in E _max, which suggests that these 2 drugs may protect the contractile status from deteriorating in the diabetic heart. By contrast, Q _max showed a significant fall after administration of oxfenicine, but not with acetyl-L-carnitine. The decrease in Q _max corresponded to an increase in total vascular resistance when treated with oxfenicine.

Conclusions

Acetyl-l-carnitine, but not oxfencine, optimizes the integrative nature of cardiac pumping mechanics by preventing the diabetes-induced deterioration in myocardial intrinsic contractility associated with unaltered LV internal resistance.     

Significance of Tumor Necrosis factor α-308 (G/A) gene polymorphism in the development of prostate cancer

Prostate cancer (PCa) is the most common noncutaneous cancer among men, accounting for 10?% of male cancer-related deaths worldwide. The etiology of PCa is largely unknown, although multiple environmental and lifestyle factors such as ultraviolet irradiation, smoking, and diet might increase the risk of the disease. Risk of disease varies most prominently with age, ethnicity, family history, and diet. The multifunctional cytokine tumor necrosis factor alpha (TNF-α) has an important role in the pathogenesis of inflammatory, autoimmune and malignant diseases. In this case control study 150 Prostate cancer patients and 150 age matched benign prostate hyperplasia (BPH) and equal number of healthy control groups were involved. The aim of this study was to analyze the effect of TNF-α-308 (G/A) polymorphism on risk of prostate cancer on north Indian prostate cancer patients. The polymerase chain reaction (PCR) technique was utilized to genotype TNF-α-308 (G/A) polymorphism. The present study showed statistically significant increased risk of prostate cancer among individuals that carried the A allele of TNF-α-308 gene (OR?=?1.81, 95?% CI 1.00–3.481, p?=?0.03).     

Polymorphisms of MLH1 in benign prostatic hyperplasia and sporadic prostate cancer

Mismatch repair is one of several DNA repair pathways of which defects may lead to cancer. We hypothesize that polymorphisms of the MLH1 gene can be a risk factor for benign prostatic hyperplasia (BPH) and prostate cancer. The genetic distribution of MLH1 polymorphisms that lead to amino acid changes at codons 132, 219, 384, and 723 were analyzed in BPH and sporadic prostate cancer patients, and compared to healthy controls from an Asian population. These experiments demonstrate a protective role for the codon 384 variant allele against prostate cancer (P = 0.031) but not BPH when compared to normal controls and furthermore, an inverse association was observed with stage (P = 0.074) and grade (P = 0.056) of cancer. This is the first report that demonstrates a protective effect for the race-related MLH1 polymorphism at codon 384 against prostate cancer and these results are important in understanding their role in this disease.     

The Influence of Genetic Drift and Selection on Quantitative Traits in a Plant Pathogenic Fungus

Genetic drift and selection are ubiquitous evolutionary forces acting to shape genetic variation in populations. While their relative importance has been well studied in plants and animals, less is known about their relative importance in fungal pathogens. Because agro-ecosystems are more homogeneous environments than natural ecosystems, stabilizing selection may play a stronger role than genetic drift or diversifying selection in shaping genetic variation among populations of fungal pathogens in agro-ecosystems. We tested this hypothesis by conducting a Q _ST/F _ST analysis using agricultural populations of the barley pathogen Rhynchosporium commune. Population divergence for eight quantitative traits (Q _ST) was compared with divergence at eight neutral microsatellite loci (F _ST) for 126 pathogen strains originating from nine globally distributed field populations to infer the effects of genetic drift and types of selection acting on each trait. Our analyses indicated that five of the eight traits had Q _ST values significantly lower than F _ST, consistent with stabilizing selection, whereas one trait, growth under heat stress (22°C), showed evidence of diversifying selection and local adaptation (Q _ST>F _ST). Estimates of heritability were high for all traits (means ranging between 0.55–0.84), and average heritability across traits was negatively correlated with microsatellite gene diversity. Some trait pairs were genetically correlated and there was significant evidence for a trade-off between spore size and spore number, and between melanization and growth under benign temperature. Our findings indicate that many ecologically and agriculturally important traits are under stabilizing selection in R. commune and that high within-population genetic variation is maintained for these traits.     

F(ST) and Q(ST) under neutrality

A commonly used test for natural selection has been to compare population differentiation for neutral molecular loci estimated by F_ST and for the additive genetic component of quantitative traits estimated by Q_ST. Past analytical and empirical studies have led to the conclusion that when averaged over replicate evolutionary histories, Q_ST = F_ST under neutrality. We used analytical and simulation techniques to study the impact of stochastic fluctuation among replicate outcomes of an evolutionary process, or the evolutionary variance, of Q_ST and F_ST for a neutral quantitative trait determined by n unlinked diallelic loci with additive gene action. We studied analytical models of two scenarios. In one, a pair of demes has recently been formed through subdivision of a panmictic population; in the other, a pair of demes has been evolving in allopatry for a long time. A rigorous analysis of these two models showed that in general, it is not necessarily true that mean Q_ST = F_ST (across evolutionary replicates) for a neutral, additive quantitative trait. In addition, we used finite-island model simulations to show there is a strong positive correlation between Q_ST and the difference Q_ST − F_ST because the evolutionary variance of Q_ST is much larger than that of F_ST. If traits with relatively large Q_ST values are preferentially sampled for study, the difference between Q_ST and F_ST will also be large and positive because of this correlation. Many recent studies have used tests of the null hypothesis Q_ST = F_ST to identify diversifying or uniform selection among subpopulations for quantitative traits. Our findings suggest that the distributions of Q_ST and F_ST under the null hypothesis of neutrality will depend on species-specific biology such as the number of subpopulations and the history of subpopulation divergence. In addition, the manner in which researchers select quantitative traits for study may introduce bias into the tests. As a result, researchers must be cautious before concluding that selection is occurring when Q_ST ≠ F_ST.     

Molecular and quantitative trait variation within and among small fragmented populations of the endangered plant species Psilopeganum sinense

Background and Aims

Natural selection and genetic drift are important evolutionary forces in determining genetic and phenotypic differentiation in plant populations. The extent to which these two distinct evolutionary forces affect locally adaptive quantitative traits has been well studied in common plant and animal species. However, we know less about how quantitative traits respond to selection pressures and drift in endangered species that have small population sizes and fragmented distributions. To address this question, this study assessed the relative strengths of selection and genetic drift in shaping population differentiation of phenotypic traits in Psilopeganum sinense, a naturally rare and recently endangered plant species.

Methods

Population differentiation at five quantitative traits (Q_ST) obtained from a common garden experiment was compared with differentiation at putatively neutral microsatellite markers (F_ST) in seven populations of P. sinense. Q_ST estimates were derived using a Bayesian hierarchical variance component method.

Key Results

Trait-specific Q_ST values were equal to or lower than F_ST. Neutral genetic diversity was not correlated with quantitative genetic variation within the populations of P. sinense.

Conclusions

Despite the prevalent empirical evidence for Q_ST > F_ST, the results instead suggest a definitive role of stabilizing selection and drift leading to phenotypic differentiation among small populations. Three traits exhibited a significantly lower Q_ST relative to F_ST, suggesting that populations of P. sinense might have experienced stabilizing selection for the same optimal phenotypes despite large geographical distances between populations and habitat fragmentation. For the other two traits, Q_ST estimates were of the same magnitude as F_ST, indicating that divergence in these traits could have been achieved by genetic drift alone. The lack of correlation between molecular marker and quantitative genetic variation suggests that sophisticated considerations are required for the inference of conservation measures of P. sinense from neutral genetic markers.     

Cellular Microcystin Content in N-Limited Microcystis aeruginosa Can Be Predicted from Growth Rate

Cell quotas of microcystin (Q_MCYST; femtomoles of MCYST per cell), protein, and chlorophyll a (Chl a), cell dry weight, and cell volume were measured over a range of growth rates in N-limited chemostat cultures of the toxic cyanobacterium Microcystis aeruginosa MASH 01-A19. There was a positive linear relationship between Q_MCYST and specific growth rate (μ), from which we propose a generalized model that enables Q_MCYST at any nutrient-limited growth rate to be predicted based on a single batch culture experiment. The model predicts Q_MCYST from μ, μ_max (maximum specific growth rate), Q_MCYSTmax (maximum cell quota), and Q_MCYSTmin (minimum cell quota). Under the conditions examined in this study, we predict a Q_MCYSTmax of 0.129 fmol cell⁻¹ at μ_max and a Q_MCYSTmin of 0.050 fmol cell⁻¹ at μ = 0. Net MCYST production rate (R_MCYST) asymptotes to zero at μ = 0 and reaches a maximum of 0.155 fmol cell⁻¹ day⁻¹ at μ_max. MCYST/dry weight ratio (milligrams per gram [dry weight]) increased linearly with μ, whereas the MCYST/protein ratio reached a maximum at intermediate μ. In contrast, the MCYST/Chl a ratio remained constant. Cell volume correlated negatively with μ, leading to an increase in intracellular MCYST concentration at high μ. Taken together, our results show that fast-growing cells of N-limited M. aeruginosa are smaller, are of lower mass, and have a higher intracellular MCYST quota and concentration than slow-growing cells. The data also highlight the importance of determining cell MCYST quotas, as potentially confusing interpretations can arise from determining MCYST content as a ratio to other cell components.     

Arabidopsis desaturase 2 gene is involved in the regulation of cadmium and lead resistance

Aims

It was shown previously that Arabidopsis (Arabidopsis thaliana) desaturase 2 (ADS2) cDNA was isolated and it was shown that the expression of ADS2 was organ-dependent and up-regulated by low temperature. However, little is known about the role of ADS2 gene in heavy metal resistance in plants. In this study, we showed that ADS2 gene is involved in the regulation of cadmium (Cd) and lead (Pb) resistance.

Methods

For heavy metal resistance tests, seeds were germinated and grown on 1/2 MS media supplemented with the indicated concentrations of metal ions. To quantify root length, plants were grown vertically in plates. For heavy metal treatments, two-week old wild-type seedlings grown on MS media were treated with cadmium (Cd) or lead (Pb) for 24 h, and then sampled for metal content measurement and qPCR analysis.

Results

ADS2 was strongly repressed by Cd(II), and ads2-1 mutant plants showed increased Cd(II) resistance. A lower Cd content was detected in ads2-1 plants than in wild-type plants subjected to Cd(II) treatment, which was associated with activation in expression of AtPDR8 gene, a pump excluding Cd(II) and/or Cd(II)-containing toxic compounds from the cytoplasm, suggesting that ADS2-mediated Cd(II) resistance is AtPDR8 dependent. We also found that ads2-1 plants showed increased Pb(II) sensitivity, and ADS2 was strongly repressed by hydrogen peroxide (H₂O₂) but not by Pb(II). The ads2-1 mutant showed increased sensitivity to oxidative stresses mediated by H₂O₂ and paraquat, and higher levels of H₂O₂ accumulation were observed in leaves of ads2-1 plants than those of wild-type plants when subjected to Pb(II) and H₂O₂, indicating that ADS2 mediates Pb(II) resistance indirectly by impaired ROS scavenging.

Conclusions

ADS2 gene mediates Cd(II) and Pb(II) resistance, at least in part, through two distinct mechanisms, an AtPDR8-dependent mechanism and a ROS detoxification system-mediated mechanism, respectively.     

Partitioning of genetic effects on lifetime performance of mice

Summary A total of 2,457 lifetime performance records of 29 genetic groups of mice was analyzed using multiple regression of records on the proportion of gene contribution from 6 lines (designated as Lines M_P, m_Q, W_P, w_Q, C_P and c_Q). Genetic effects were partitioned into line additive, line maternal, direct heterosis, maternal heterosis and paternal heterosis effects. The line additive and line maternal effects were expressed as deviations from Line c_Q. Seventeen of 25 line additive effects differed significantly (P<0.05) from Line c_Q whereas only 4 of 25 line maternal effects deviated significantly from Line c_Q. Deviations in line additive effects from c_Q were negative in all lines examined whereas deviations in line maternal effects from c_Q were all positive, indicating a negative relationship between line additive and line maternal effects. Direct heterosis effects were all positive and significant (P < 0.01) except in the M_PxW_P cross which was produced by mating Lines M_P and W_P of the same base population (P). Maternal heterosis effects were significant in 10 of 20 cases whereas paternal heterosis effects were significant in 13 of 20 cases. Although direct heterosis is a major component of total heterosis effects (sum of direct, maternal and paternal heterosis), the results suggest that parental heterosis may need to be considered in producing multiple way crosses. The fitting of line additive, line maternal, direct heterosis, maternal heterosis and paternal heterosis effects in the multiple regression model effectively accounted for all genetic effects in lifetime performance.Animal Research Centre Contribution No. 1326     

Sequencing of Comamonas testosteroni strain B-356-biphenyl/chlorobiphenyl dioxygenase genes: evolutionary relationships among Gram-negative bacterial biphenyl dioxygenases

In a previous work, all three components of Comamonas testosteroni B-356 biphenyl (BPH)/chlorobiphenyls (PCBs) dioxygenase (dox) have been purified and characterized. They include an iron-sulphur protein (ISP_BPH) which is the terminal oxygenase composed of two subunits (encoded by bphA and bphE), a ferredoxin (FER_BPH) encoded by bphF and a reductase (RED_BPH) encoded by bphG. bphG Is not located in the neighbourhood of bphAEF in B-356. We are reporting the cloning of B-356-bphG and the sequencing of B-356-BPH dox genes. Comparative analysis of the genes provided genetic evidence showing that two BPH dox lineages have emerged in Gram-negative bacteria. The main features of the lineage that includes B-356 are the location of bphG outside the bph gene cluster and the structure of RED_BPH which is very distinct from all other aryl dioxygenase-reductases.     

QTL mapping of stalk bending strength in a recombinant inbred line maize population

Stalk bending strength (SBS) is a reliable indicator for evaluating stalk lodging resistance of maize plants. Based on biomechanical considerations, the maximum load exerted to breaking (F _max), the breaking moment (M _max) and critical stress (σ _max) are three important parameters to characterize SBS. We investigated the genetic architecture of SBS by phenotyping F _max, M _max and σ _max of the fourth internode of maize plants in a population of 216 recombinant inbred lines derived from the cross B73 × Ce03005 evaluated in four environments. Heritability of F _max, M _max and σ _max was 0.81, 0.79 and 0.75, respectively. F _max and σ _max were positively correlated with several other stalk characters. By using a linkage map with 129 SSR markers, we detected two, three and two quantitative trait loci (QTL) explaining 22.4, 26.1 and 17.2 % of the genotypic variance for F _max, M _max and σ _max, respectively. The QTL for F _max, M _max and σ _max located in adjacent bins 5.02 and 5.03 as well as in bin 10.04 for F _max were detected with high frequencies in cross-validation. As our QTL mapping results suggested a complex polygenic inheritance for SBS-related traits, we also evaluated the prediction accuracy of two genomic prediction methods (GBLUP and BayesB). In general, we found that both explained considerably higher proportions of the genetic variance than the values obtained in QTL mapping with cross-validation. Nevertheless, the identified QTL regions could be used as a starting point for fine mapping and gene cloning.     

Zinc and cadmium analysis in human prostate neoplasms

The objective of this study was to test the hypothesis that prostatic cancer is associated with the changes of zinc (Zn) and cadmium (Cd) concentration. Normal prostate, benign prostatic hyperplasia (BPH), and prostatic carcinoma (PCA) were analyzed for Zn and Cd by atomic absorption spectrometry. Cd level was measured using a graphite furnace and Zn level was measured by flame mode. Metal content was assessed in whole tissues and in nuclear, plasma membrane, and cytosolic fractions. An increase of Zn content in BPH, but a decrease in PCA as compared to normal tissue, was observed. Cd concentration appeared to be higher in BPH and PCA than in normal tissue. No correlation between Zn and Cd level was found in BPH specimens obtained from the same patients. Probability values ofp ≤0.05 were considered to indicate significant differences. Obtained results seem to support the hypothesis of Cd carcinogenicity and preventing function of Zn in prostatic cancer. Plasma membrane fraction corresponding to lysosomal, mitochondrial, and microsomal subcellular compartments are probably critical in Zn and Cd participation in human prostate neoplasms.     

Simultaneous extraction of soil phytoavailable cadmium,copper, and lead by chelating resin membrane

Cadmium, copper, and lead were extracted from suspensions of contaminated soils using metal chelating exchange resin membranes. Nine soils with widely varying properties and Cd, Cu and Pb levels were tested. Soil suspensions made up with 4 g in 40 mL deionized water were equilibrated with 5 cm² Ca-saturated Chelex exchange resin membrane which was retained inside a polypropylene bag and shaken at 150 rpm for 24 hrs. Resin membrane extractable Cd, Cu and Pb of the soils were correlated with Cd, Cu, and Pb uptake by young wheat seedlings grown in these soils and compared with soil Cd, Cu, and Pb extracted by 0.1 M HCl, 0.01 M CaCl₂, and 0.005 M Diethylenetriamine pentaacetic acid (DTPA). The amounts of Cd, Cu and Pb extracted by the Ca-saturated Chelex membrane from all tested soils correlated well with those absorbed by young wheat seedlings. The Ca-saturated Chelex membrane extractable Cd, Cu and Pb of the soil had the strongest correlation with plant uptake Cd, Cu and Pb among the extraction methods we tested. It was demonstrated that the Ca-saturated Chelex membrane extraction is an appropriate method in simultaneously estimating Cd, Cu and Pb phytoavailability of soil and is applicable to a wide range of soils.