Phytoremediation of selenium‐contaminated soils: the efficiency of different cropping systems

Field experiments were conducted at two locations in the seleniferous region of northwestern India from 2001 to 2006 to evaluate the efficiency of four cropping systems in removing Se from contaminated soil containing 2843–4345 μg Se per kg in the surface layer (0–15 cm). Rapeseed (Brassica napus) followed by arhar (Cajanus cajan), sunn hemp (Crotalaria juncea) or cotton (Gossypium arboretum) and wheat (Triticum aestivum) followed by rice (Oryza sativa) were the four cropping systems. The total biomass generated by Brassica‐based systems ranged from 16 to 21 t/ha when harvested at maturity. Corresponding values for a wheat–rice sequence were 22–26 t/ha. Among the different crops at both the experimental sites, the highest Se content was recorded in leaves (157–209 mg/kg), grains (64–201 mg/kg) and stems (42–93 mg/kg) of Brassica and the lowest in the shoots (10–27 mg/kg), grains (5–13 mg/kg) and straw (13–20 mg/kg) of the rice crop. Except for S and P, concentrations of other nutrients (Zn, Cu, Mn and Fe) were not significantly affected by variations in the Se content of plants. Significant correlation coefficients were observed between Se and S (r = 0.838, P ≤ 0.001), Se and P (r = 0.817, P ≤ 0.001) at the peak flowering stage (n = 16), and r = 0.743, P ≤ 0.001 and r = 0.498, P ≤ 0.05, respectively, at the maturity stage (n = 16). Total Se removal through harvested biomass of rapeseed‐based cropping sequences varied from 716 to 1374 g/ha/yr at peak flowering and 736–949 g/ha/yr at the maturity stage. Corresponding values for a wheat–rice system were 435–492 and 370–517 g/ha/yr, respectively. The amount of Se recycled through leaf senescence ranged from 255 to 500 g/ha/yr for Brassica‐based cropping systems. In the wheat–rice system, Se addition through irrigation varied from 170 to 243 g/ha/yr and was three to four times more than that added in Brassica‐based systems. On completion of the phytoremediation experiments at site I, Se removal through harvested biomass at maturity was 1.7–5.1% of total Se in the soil down to a depth of 120 cm and 4.8–13.2% at site II. Analysis showed that Se losses under different crop rotations were 18.5–24.5% at site I and 21–33% at site II of total soil Se. Thus, at both sites 16–20% of total Se lost from the soil was unexplained. Results show that Brassica‐based cropping systems lead to significant reductions in Se capital of contaminated soil over 2–3 years. Although a long‐term commitment is required, adoption of Brassica‐based systems as a regular agricultural practice must lead to sustainable management of seleniferous soils.     

Histomorphometry and vitamin D metabolism of valgus-varus deformity in broiler chickens

Vitamin D metabolite levels and tibiotarsal histomorphometric characteristics were determined in 49-day-old male broilers. Valgus-varus bone deformity was present in 5.2% and tibial dyschondroplasia (TD) in 3% of these broilers, which were raised on floor litter under seemingly normal nutritional, space, and lighting conditions. No significant weight differences were observed between normal and lame broilers. The plasma levels of 25-OH-D were the same in lame and normal broilers. However, 1,25-(OH)2D plasma levels were reduced 28% in broilers with valgus-varus deformities but normal in broilers with TD. Anatomically, there were three different patterns of bone development in the undecalcified mid-diaphyseal sections. The pattern with the least periosteal growth, lowest tetracycline labeling, and smallest marrow cavity was most often seen in valgus-varus deformities. Patterns with greatest periosteal growth, high tetracycline labeling, and larger marrow cavities were more representative of normal broilers. It was hypothesized that defective prostaglandin metabolism reduced 1,25-(OH)2D levels, contributing to the overall reduction in bone formation and bone resorption observed in broilers with valgus-varus bone deformity.     

A brown dwarf mass donor in an accreting binary

A long-standing and unverified prediction of binary star evolution theory is the existence of a population of white dwarfs accreting from substellar donor stars. Such systems ought to be common, but the difficulty of finding them, combined with the challenge of detecting the donor against the light from accretion, means that no donor star to date has a measured mass below the hydrogen burning limit. We applied a technique that allowed us to reliably measure the mass of the unseen donor star in eclipsing systems. We were able to identify a brown dwarf donor star, with a mass of 0.052 +/- 0.002 solar mass. The relatively high mass of the donor star for its orbital period suggests that current evolutionary models may underestimate the radii of brown dwarfs.     

Wild melon diversity in India (Punjab State)

We present here the first comprehensive genetic characterization of wild melon accessions from northern India. The genetic diversity among 43 wild melon accessions collected from the six agro-ecological regions of the Punjab State of India was assessed by measuring variation at 16 Simple Sequence Repeat (SSR) loci, morphological traits of plant habit and fruit morphological traits, two yield-associated traits, root nematode resistance and biochemical composition (ascorbic acid, carotenoids, titrable acidity). Variation among accessions was observed in plant habit and fruit traits and wild melon germplasm with high acidity and elevated carotenoid content and possessing resistance to Meloidogyne incognita was identified in the collection. A high level of genetic variability in wild melon germplasm was suggested by SSR analysis. Comparative analysis using SSRs of the genetic variability between wild melons from the north and other melons from the south and east regions of India and also reference accessions of cultivated melon from Spain, Japan, Korea, Maldives, Iraq and Israel, showed regional differentiation among Indian melon accessions and that Indian germplasm was not closely related to melon accessions from other parts of the world. A highly drought tolerant accession belonging to var. agrestis Naud. was also identified.     

Immunohistochemistry Diagnosis of an Ovarian Dysgerminoma in One Bitch

An ovarian enlargement (diameter, 8 cm) was identified and surgically excised from a 5-year-old female dog. Microscopic examination of the multinodular neoplasm revealed sheets of polygonal neoplastic cells with large nuclei, frequent mitosis, necrosis and haemorrhage. Immunohistochemically, the neoplastic cells were positive for vimentin and alkaline phosphatase but were negative for CD3, CD79a, cytokeratin, alpha-fetoprotein, inhibin-α and S-100. The histopathological diagnosis of the mass was unilateral ovarian dysgerminoma.     

Variation and covariation for Gibberella ear rot resistance and agronomic traits in testcrosses of doubled haploid maize lines

Gibberella ear rot (GER) of maize caused by Fusarium graminearum reduces grain yield and leads to contamination of the grains with deoxynivalenol (DON), a mycotoxin that adversely affects the health of humans and animals. The objectives of this study were to (1) analyze means and genotypic variances for line per se performance (LP) and testcross performance (TP) of doubled haploid (DH) lines for GER severity and DON concentration as well as for some agronomic traits, (2) examine correlations among these traits, (3) validate QTL for resistance detected in previous studies for LP and their effect on TP and (4) investigate the relative efficiency of indirect selection (RE) for LP to improve TP. Testcross progenies of 94 DH lines originating from four flint populations were developed using a susceptible dent tester as pollinator. Artificial inoculations with F. graminearum led to appreciable disease development. Average TP for GER severity and DON concentration were lower than the mean mid-parent values of the tester and DH lines, indicating mid-parent heterosis for resistance. Genotypic variation for resistance was significant for LP and TP. Genotypic correlations between LP and TP were low and resistance QTL for LP had no significant effects on TP. Accordingly, RE for resistance was low, suggesting to allocate resources mostly to the evaluation of testcrosses. Correlations of resistance to GER and DON contamination with grain yield (measured under non-inoculated conditions) were not significant, indicating that selection for resistance and higher grain yield can be carried out simultaneously.     

Detection of avian polyomavirus infection by polymerase chain reaction using formalin-fixed, paraffin-embedded tissues

Avian polyomavirus infection in psittacines was diagnosed in tissues by the use of polymerase chain reaction (PCR) test. The tissues used in the procedure were either formalin-fixed tissues embedded in paraffin blocks or fresh tissues (heart, liver, and spleen) collected from the psittacines during necropsy. DNA was extracted from these tissues and was tested with the published primers for avian polyomavirus VP1 gene in the PCR that yielded an amplicon of 550 base pair size, which was then visualized by electrophoresis. The amplicon size was consistent with avian polyomavirus. The PCR test was found to be an effective method for identifying avian polyomavirus infection in both formalin-fixed, paraffin-embedded and fresh tissues from psittacine birds of different age groups.     

Sequential bacteriological observations in relation to cell-mediated and humoral antibody responses of cattle infected with Mycobacterium paratuberculosis and maintained on normal or high iron intake

Twenty calves were orally infected with Mycobacterium paratuberculosis before weaning. Ten of these plus 4 non-infected controls were maintained on elevated dietary iron intake from 6 to 33 months of age. During this time, in which the majority of animals were bred, the influence of increased dietary iron upon tests of cellular and humoral immune responsiveness to antigens of the organism were monitored. Results were examined in relation to the organism's capacity to multiply and infect up to 7 portions of the intestinal tract. No significant differences were detected in the degree of intestinal disease or pattern of faecal excretion of M. paratuberculosis in iron supplemented and non-supplemented cattle. Cutaneous delayed-type hypersensitivity (DTH) to johnin PPD developed at 1 month and in-vitro lymphocyte and immunostimulatory activity (LS) to this antigen at 2 months after infection. LS indices were significantly reduced in magnitude in iron-supplemented cattle (p less than 0.01). Most ELISA antibody responses were positive 10 to 17 months after infection and preceded the fewer number of CF responses by several months. Neither of the antibody tests was affected by elevated iron intake. Generally, complete or partial resistance to paratuberculosis was associated with sustained positive monthly LS tests (index greater than or equal to 2.0), whereas antibody levels tended to be sustained only in the more severely affected cattle. Although neither test system was affected by pregnancy the ELISA failed to detect a significant proportion of cattle chronically shedding M. paratuberculosis in faeces.