Do soil cadmium concentrations decline after phosphate fertiliser application is stopped: A comparison of long-term pasture trials in New Zealand?

Decreasing soil cadmium (Cd) is one method of removing Cd from the food chain. Phosphorus (P) fertilisers are a major source of Cd inputs into soil. Stopping P fertiliser should theoretically decrease Cd inputs and soil Cd accumulation, but there are few field data to show if this occurs. We examined three long-term grazed pasture trials in New Zealand (Ballantrae, Winchmore and Whatawhata) where P fertiliser had been applied (from 10 to 100 kg P ha-1 yr-1) for up to six years and then stopped for 10 to 26 years. Stopping P fertiliser applications reduced soil Cd concentrations at Winchmore and Whatawhata where P had been applied at ≥34 kg P ha-1 yr-1. No reductions occurred below this rate nor at Ballantrae where only 10 years post P-application data were available. Decreases were ascribed to moderate rainfall (1630 mm at Whatawhata and 740 mm rainfall plus 770 mm irrigation at Winchmore) that enhanced Cd leaching and may have been aided at Winchmore by a decrease in soil pH over time (0.4 units). However, because stopping P fertiliser inputs may quickly impair pasture production, additional strategies may be required to decrease soil Cd quickly.

Cadmium uptake by onions, lettuce and spinach in New Zealand: Implications for management to meet regulatory limits.

Paired soil and plant samples collected from the main commercial growing areas for onions (Allium cepa), lettuce (Lactuca sativa) and spinach (Spinacia olearacea) in New Zealand were used to assess the influence of plant and soil factors on cadmium (Cd) uptake in these crops. Differences in Cd concentration between eight lettuce sub-types were not consistent across sites, nor were differences in Cd concentrations in three crisphead cultivars assessed at two sites. Similarly, differences in Cd concentrations between four onion cultivars were inconsistent across sites. Mean lettuce Cd concentrations in eight lettuce varieties (range 0.005-0.034 mg∙kg-1 (fresh weight, FW) were markedly lower than those in baby leaf and bunching spinach, (range 0.005-0.19 mg∙kg-1 FW). Significant regional variation was observed in Cd concentrations in one onion cultivar (mean range 0.007-0.05 mg∙kg-1 FW). Soil Cd concentration, pH and region were statistically significant predictors of onion Cd concentration, explaining low (38% for soil Cd and pH) to moderate (50% for all three parameters) percentage of the variation. Soil Cd concentration and exchangeable magnesium or total carbon were statistically significant predictors of Cd concentration in baby leaf and bunching spinach, respectively, explaining a moderate percentage (49% and 42%) of the variation in Cd concentration. Increasing pH and soil carbon may assist in minimising Cd uptake in onion and bunching spinach, respectively. The low to moderate proportion of explained variation is partly attributable to the narrow range in some measured soil properties and indicates factors other than those assessed are influencing plant uptake. This highlights a challenge in using these relationships to develop risk-based soil guideline values to support compliance with food standards. Similarly, the inconsistency in Cd concentrations in different cultivars across sites highlights the need for multi-site assessments to confirm the low Cd accumulation status of different cultivars.

An assessment of the effect of contact time on cadmium phytoavailability in a pasture soil.

The length of time cadmium (Cd) is in contact with the soil has been recognised as a factor affecting phytoavailability, but the extent of this process is currently poorly understood. This study used isotopic dilution techniques (E and L values) to determine the effect of contact time on Cd phytoavailability from soil collected from a long-term phosphorus (P) fertiliser trial. Cadmium phytoavailability was determined in soil that was last fertilised with soluble Cd from P fertiliser 17 years prior to sampling (residual plots) and soil that received annual applications of P fertiliser until sampling (continuous plots). It was found that both E values and L values increased with P fertiliser (viz Cd) inputs and were significantly related to each other (r 2 = 0.82 P < 0.005). There was however no significant difference (P < 0.05) in the percentage of total Cd that was phytoavailable calculated using E values (E%) between the continuous (mean 51 %) and the residual plots (mean 51 %). There was also no significant difference (P < 0.05) in the percentage of total soil Cd that was phytoavailable calculated using L values (L%) between the continuous (mean 77 %) and residual plots (mean 87 %). These results suggest that despite Cd being in contact with the soil for 17 years, there was no difference in the size of the phytoavailable Cd pool compared to recent Cd inputs. This study should be repeated for other soil types and factored into any analysis for the long-term implications of ongoing Cd accumulation in soil on future landuse.

Quality defects in market beef and dairy cows and bulls sold through livestock auction markets in the Western United States: II. Relative effects on selling price.

Relative effects of Beef Quality Assurance (BQA)-related defects in market beef and dairy cows and bulls on selling price at auction was evaluated during 2008. The presence and severity of 23 BQA-related traits were determined during sales in Idaho, California, and Utah. Overall, 18,949 unique lots consisting of 23,479 animals were assessed during 125 dairy sales and 79 beef sales. Mean sale price ± SD (per 45.5 kg) for market beef cows, beef bulls, dairy cows, and dairy bulls was $45.15 ± 9.42, $56.30 ± 9.21, $42.23 ± 12.26, and $55.10 ± 9.07, respectively. When combined, all recorded traits explained 36% of the variation in selling price in beef cows, 35% in beef bulls, 61% in dairy cows, and 56% in dairy bulls. Premiums and discounts were determined in comparison with a "par" or "base" animal. Compared with a base BCS 5 beef cow (on a 9-point beef scale), BCS 1 to 4 cows were discounted (P < 0.0001), whereas premiums (P < 0.05) were estimated for BCS 6 to 8. Compared with a base BCS 3.0 dairy cow (on a 5-point dairy scale), more body condition resulted in a premium (P ≤ 0.001), whereas a less-than-desirable BCS of 2.0 or 2.5 was discounted (P < 0.0001). Emaciated or near-emaciated cows (beef BCS 1 or 2; dairy BCS 1.0 or 1.5) were discounted (P < 0.0001). Compared with base cows weighing 545 to 635 kg, lighter BW beef cows were discounted (P < 0.0001), whereas heavier beef cows received (P < 0.05) a premium. Compared with a base dairy cow weighing 636 to 727 kg, lighter BW cows were discounted (P < 0.0001), whereas heavier cows (727 to 909 kg) received a premium (P < 0.01). Beef and dairy cows with any evidence of lameness were discounted (P < 0.0001). Presence of ocular neoplasia in the precancerous stage discounted (P = 0.05) beef cows and discounted (P < 0.01) dairy cows, whereas at the cancerous stage, it discounted (P < 0.0001) all cows. Hide color influenced (P < 0.0001) selling price in beef cattle but had no effect (P = 0.17) in dairy cows. Animals that were visibly sick were discounted (P < 0.0001). Results suggest that improving BCS and BW, which producers can do at the farm or ranch level, positively affects sale price. Furthermore, animals that are visibly sick or have a defect associated with a possible antibiotic risk will be discounted. Ultimately, animals with minor quality defects should be sold in a timely manner before the defect advances and the discount increases.

Survey of quality defects in market beef and dairy cows and bulls sold through livestock auction markets in the Western United States: I. Incidence rates.

A survey was conducted to quantify incidence of Beef Quality Assurance (BQA)-related defects in market beef and dairy cows and bulls selling at auction during 2 seasons in 2008. Twenty-three BQA-related traits were evaluated by 9 trained personnel during sales at 10 livestock auction markets in Idaho (n = 5; beef and dairy), California, (n = 4; dairy only), and Utah (n = 1; beef and dairy). Overall, 18,949 unique lots (8,213 beef cows, 1,036 beef bulls, 9,177 dairy cows, and 523 dairy bulls,) consisting of 23,479 animals (9,299 beef cows, 1,091 beef bulls, 12,429 dairy cows, and 660 dairy bulls) were evaluated during 125 sales (64 spring, 61 fall) for dairy and 79 sales (40 spring, 39 fall) for beef. The majority of market beef cows and bulls (60.9 and 71.3%, respectively) were predominantly black-hided, and the Holstein hide pattern was observed in 95.4 and 93.6% of market dairy cows and bulls, respectively. Market cattle weighed 548 ± 103.6 kg (beef cows), 751 ± 176.1 kg (beef bulls), 658 ± 129.7 kg (dairy cows), and 731 ± 150.8 kg (dairy bulls). Most beef cows (79.6%) weighed 455 to 726 kg, and most beef bulls (73.8%) weighed 545 to 954 kg, respectively. Among market beef cattle, 16.0% of cows and 14.5% of bulls weighed less than 455 and 545 kg, respectively, and 63.7% of dairy cows and 81.5% of dairy bulls weighed 545 to 817 kg or 545 to 954 kg, respectively. However, 19.5% of dairy cows and 13.1% of dairy bulls weighed less than 545 kg. Mean BCS for beef cattle (9-point scale) was 4.7 ± 1.2 (cows) and 5.3 ± 0.9 (bulls), and for dairy cattle (5-point scale) was 2.6 ± 0.8 (cows) and 2.9 ± 0.6 (bulls). Some 16.5% of beef cows and 4.1% of beef bulls had a BCS of 1 to 3, whereas 34.8% of dairy cows and 10.4% of dairy bulls had a BCS of 2 or less. Emaciation (beef BCS = 1, dairy BCS = 1.0) or near-emaciation (beef BCS = 2, dairy BCS = 1.5) was observed in 13.3% of dairy cows and 3.9% of beef cows. Among beef cattle, 15.1% of cows and 15.4% of bulls were considered lame. In contrast, 44.7% of dairy cows and 26.1% of dairy bulls were lame. Ocular neoplasia (cancer eye) was observed in only 0.6% of beef cows, 0.3% of beef bulls, 0.3% of dairy cows, and 0.0% of dairy bulls. However, among animals with ocular neoplasia, it was cancerous in 34.4% of beef bulls, 48.0% of dairy cows, and 73.3% of beef cows. In conclusion, numerous quality defects are present in market beef and dairy cattle selling at auction in the Western United States, which could influence their value at auction.

The mitogen-activated/extracellular signal-regulated kinase kinase 1/2 inhibitor U0126 induces glial fibrillary acidic protein expression and reduces the proliferation and migration of C6 glioma cells.

The extracellular signal-regulated kinase (ERK) signaling pathway has been implicated in diverse cellular functions. ERK and its activating kinase, mitogen-activated/extracellular signal-regulated kinase kinase (MEK), are downstream of cell surface receptors known to be up-regulated in many malignant gliomas. We sought to investigate the role of ERK in glioma cell migration, proliferation and differentiation using the rat-derived C6 glioma cell line and the MEK inhibitor, U0126. Treatment of C6 cells with U0126 caused a significant concentration-dependent reduction in cell proliferation and migration and also induced expression of glial fibrillary acidic protein, a marker of astrocytic differentiation. These results suggest that the ERK pathway regulates glioma cell proliferation, migration and differentiation.

The over-expression of the wild type or mutant forms of the presenilin-1 protein alters glycoprotein processing in a human neuroblastoma cell line.

Mutations in the presenilin proteins (PS1 and PS2) are responsible for more than 70% of the cases of the familial form of Alzheimer's disease (FAD). The proteins are expressed in the cell at a low level, primarily in the endoplasmic reticulum and cis Golgi, where they have been proposed to play a role in protein processing. As protein glycosylation is a key post-translational event that occurs within the Golgi, we have investigated the effect of altered PS1 expression levels on the protein glycosylation pattern using the SH-SY5Y human neuroblastoma cell line. In cells over-expressing either the wild type or mutant (M146L) PS1-FAD proteins, there was a decrease in the expression levels of protein-bound alpha2,3-linked sialic acid residues at the level of the cell membrane. This was particularly manifest as a significant decrease in the expression of the polysialic acid chain that is linked to the core oligosaccharide of the neural cell adhesion molecule in an alpha2,3 bond. These results suggest that the over-expression of either the wild type or mutant PS1 disturbs glycoprotein processing within the Golgi.

SELEX selection of high-affinity oligonucleotides for bacteriophage Ff gene 5 protein.

The Ff gene 5 protein (g5p) is a cooperative ssDNA-binding protein. SELEX was used to identify DNA sequences favorable for g5p binding at physiological ionic strength (200 mM NaCl) and 37 degrees C. Sequences were selected from a library of 58-mers that contained a central variable segment of 26 nucleotides. DNA sequences selected after eight rounds of SELEX were mostly G-rich, with multiple copies of CPuGGPy, TPuGGGPy, and/or PyPuPuGGGPy motifs. This was unexpected, since g5p has higher binding affinities for polypyrimidine than for polypurine sequences. The most recurrent G-rich sequence, named I-3, was found to have g5p-binding properties that were correlated with a structural transition. At 10 mM NaCl, I-3 existed in a single-stranded form that was saturated by g5p in an all-or-none fashion. At 200 mM NaCl, I-3 existed in a structured form that showed CD spectral features of G-quadruplexes. The g5p binding affinity for this structured form of I-3 was >100-fold higher than for the single-stranded form. Moreover, the structured I-3 was saturated by g5p in two steps, the first of which was the formation of an apparent initiation complex consisting of one I-3 strand and about three g5p dimers. Nuclease S1 footprinting and other experiments showed that g5p molecules in the initiation complex at 200 mM NaCl were bound directly to the G-rich variable segment and that the structure of I-3 was retained after saturation by g5p. Thus, G-rich motifs may form structures favorable for initiation of g5p binding and also provide the actual g5p-binding sites.

Characterization of human HtrA2, a novel serine protease involved in the mammalian cellular stress response.

Human HtrA2 is a novel member of the HtrA serine protease family and shows extensive homology to the Escherichia coli HtrA genes that are essential for bacterial survival at high temperatures. HumHtrA2 is also homologous to human HtrA1, also known as L56/HtrA, which is differentially expressed in human osteoarthritic cartilage and after SV40 transformation of human fibroblasts. HumHtrA2 is upregulated in mammalian cells in response to stress induced by both heat shock and tunicamycin treatment. Biochemical characterization of humHtrA2 shows it to be predominantly a nuclear protease which undergoes autoproteolysis. This proteolysis is abolished when the predicted active site serine residue is altered to alanine by site-directed mutagenesis. In human cell lines, it is present as two polypeptides of 38 and 40 kDa. HumHtrA2 cleaves beta-casein with an inhibitor profile similar to that previously described for E. coli HtrA, in addition to an increase in beta-casein turnover when the assay temperature is raised from 37 to 45 degrees C. The biochemical and sequence similarities between humHtrA2 and its bacterial homologues, in conjunction with its nuclear location and upregulation in response to tunicamycin and heat shock suggest that it is involved in mammalian stress response pathways.

Alzheimer's disease: correlation of the suppression of beta-amyloid peptide secretion from cultured cells with inhibition of the chymotrypsin-like activity of the proteasome.

Peptide aldehyde inhibitors of the chymotrypsin-like activity of the proteasome (CLIP) such as N-acetyl-Leu-Leu-Nle-H (or ALLN) have been shown previously to inhibit the secretion of beta-amyloid peptide (A beta) from cells. To evaluate more fully the role of the proteasome in this process, we have tested the effects on A beta formation of a much wider range of peptide-based inhibitors of CLIP than published previously. The inhibitors tested included several peptide boronates, some of which proved to be the most potent peptide-based inhibitors of beta-amyloid production reported so far. We found that the ability of the peptide aldehyde and boronate inhibitors to suppress A beta formation from cells correlated extremely well with their potency as CLIP inhibitors. Thus, we conclude that the proteasome may be involved either directly or indirectly in A beta formation.

Presenilin-1 is processed into two major cleavage products in neuronal cell lines.

Presenilin-1 (PS-1) has been identified as the protein encoded by the chromosome 14 locus that, when mutated, leads to familial Alzheimer's disease (FAD). Using PS-1 transfected SHSY5Y neuroblastoma cells, we have demonstrated by immunodetection, using polyclonal antibodies, that PS-1 is processed to give two fragments: an N-terminal 28 kDa fragment, and a C-terminal 18 kDa fragment. In a number of non-transfected cell types, most PS-1 is detected as the cleaved products. The molecular weights of the PS-1 cleavage products suggest that the cleavage point will most probably be within a region of the hydrophilic loop domain coded for by either exon 8 or 9 of the PS-1 gene. The clustering of FAD mutations within exon 8 strongly suggests that it encodes a key functional domain. It seems likely that the cleavage of PS-1 is crucial to some aspect of its functionality. An understanding of this process will give insights into the pathology of AD, and may offer new opportunities for therapeutic intervention.

PA28 activator protein forms regulatory caps on proteasome stacked rings.

The proteasome is a 700,000 dalton proteolytic complex found in eukaryotes and, in a simpler form, in archaebacteria. Its distinctive architecture consists of a stack of four rings, each containing approximately six to eight 21,000 to 35,000 dalton subunits. In this report, we describe the use of electron microscopy of negatively stained specimens, including alignment and averaging of multiple digitized images, to investigate the complexes formed between eukaryotic proteasomes and a recently-isolated 28,000 dalton eukaryotic proteasome activator, PA28. We find that purified PA28, which was previously shown to have a native molecular mass consistent with oligomerization of the PA28 polypeptide, occurs as a ring of variably-positioned protein subunits. In one set of images, these subunits appear to be tethered to a central hub. When incubated with proteasomes, PA28 forms oligomeric regulatory caps on both ends of eukaryotic proteasomes, with the proteasome outer rings serving as scaffolds to which the bases of the regulatory caps are attached. The base of each cap consists of a thickened protein mass, so that the base is wider than the tip of the cap. A stain-filled channel penetrates into each cap from its tip, indicating that the protein subunits tend to separate somewhat at the tip. The caps are about 10 to 11 nm wide at the base and 7 to 8 nm long from base to tip. This is the first direct visualization of the interaction between proteasomes and a purified, functionally characterized protein modulator of proteasome activity, and it gives the first insight as to the particle geometry through which activation by PA28 must occur. The capping at both ends implies the existence of an underlying 2-fold symmetry (or pseudosymmetry) in the eukaryotic proteasome, suggesting that proteasomes may consist of two identical or quasi-identical structural units which interact at a central interface.

Surgical repair of tusk injury (pulpectomy) in an adult, male forest elephant (Loxodonta cyclotis).

A 15-year-old male forest elephant housed in a zoo sustained a fracture of the right tusk that was 10 cm inside the cheek pouch, thus exposing the tusk canal. Treatment of the cavity by packing, topical application of antibiotics, and administration of various antiseptic preparations failed; however, the tusk grew. To treat the infected, growing tusks's root canal or pulp, surgery--comparable to a pulpectomy in man--was performed with successful results.

Silent hemoglobin alpha genes in apes: potential source of thalassemia.

Small quantities of unusual hemoglobins were found in 1 of 37 chimpanzees and 2 of 6 gorillas. In each genus these hemoglobins contain unique alpha chains that differ from the ordinary by eight to nine scattered amino acid changes. The unusual chains arise from a hitherto undetected hemoglobin (3)alpha locus. No (3)alpha products are found in most apes; accordingly, (3)alpha is considered synthetically inactive in all but a few reversion mutants. Indirect evidence that the inactive (3)alpha locus is juxtaposed to an active alpha locus together with the supposition that (3)alpha exists in man provides a setting wherein thalassemia might be produced by nonhomologous recombination between two loci.