Coupling Phosphate-Solubilizing Bacteria with Phosphorus Supplements Improve Maize Phosphorus Acquisition and Growth under Lime Induced Salinity Stress

Global warming promotes soil calcification and salinization processes. As a result, soil phosphorus (P) is becoming deficient in arid and semiarid areas throughout the world. In this pot study, we evaluated the potential of phosphate-solubilizing bacteria (PSB) for enhancing the growth and P uptake in maize under varying levels of lime (4.8%, 10%, 15% and 20%) and additional P supplements (farmyard manure, poultry manure, single super phosphate and rock phosphate) added at the rate of 45 mg P₂O₅ kg⁻¹. Inoculation and application of P as organic manures (Poultry and farm yard manures) improved maize growth and P uptake compared to the control and soils with P applied from mineral sources. Liming adversely affected crop growth, but the use of PSB and organic manure significantly neutralized this harmful effect. Mineral P sources combined with PSB were as effective as the organic sources alone. Furthermore, while single supper phosphate showed better results than Rock phosphate, the latter performed comparably upon PSB inoculation. Thus, PSB plus P application as organic manures is an eco-friendly option to improve crop growth and P nutrition in a calcareous soil under changing climate.

Arsenic in a groundwater environment in Bangladesh: Occurrence and mobilization

Groundwater with an excessive level of Arsenic (As) is a threat to human health. In Bangladesh, out of 64 districts, the groundwater of 50 and 59 districts contains As exceeding the Bangladesh (50 μg/L) and WHO (10 μg/L) standards for potable water. This review focuses on the occurrence, origin, plausible sources, and mobilization mechanisms of As in the groundwater of Bangladesh to better understand its environmental as well as public health consequences. High As concentrations mainly was mainly occur from the natural origin of the Himalayan orogenic tract. Consequently, sedimentary processes transport the As-loaded sediments from the orogenic tract to the marginal foreland of Bangladesh, and under the favorable biogeochemical circumstances, As is discharged from the sediment to the groundwater. Rock weathering, regular floods, volcanic movement, deposition of hydrochemical ore, and leaching of geological formations in the Himalayan range cause As occurrence in the groundwater of Bangladesh. Redox and desorption processes along with microbe-related reduction are the key geochemical processes for As enrichment. Under reducing conditions, both reductive dissolution of Fe-oxides and desorption of As are the root causes of As mobilization. A medium alkaline and reductive environment, resulting from biochemical reactions, is the major factor mobilizing As in groundwater. An elevated pH value along with decoupling of As and HCO₃^- plays a vital role in mobilizing As. The As mobilization process is related to the reductive solution of metal oxides as well as hydroxides that exists in sporadic sediments in Bangladesh. Other mechanisms, such as pyrite oxidation, redox cycling, and competitive ion exchange processes, are also postulated as probable mechanisms of As mobilization. The reductive dissolution of MnOOH adds dissolved As and redox-sensitive components such as SO₄^2- and oxidized pyrite, which act as the major mechanisms to mobilize As. The reductive suspension of Mn(IV)-oxyhydroxides has also accelerated the As mobilization process in the groundwater of Bangladesh. Infiltration from the irrigation return flow and surface-wash water are also potential factors to remobilize As. Over-exploitation of groundwater and the competitive ion exchange process are also responsible for releasing As into the aquifers of Bangladesh.

Alleviation of chromium toxicity in maize by Fe fortification and chromium tolerant ACC deaminase producing plant growth promoting rhizobacteria

Chromium (Cr) is becoming a potential pollutant with the passage of time. Higher intake of Cr does not only affect the productivity of crops, but also the quality of food produced in Cr polluted soils. In the past, foliar application of Fe is widely studied regarding their potential to alleviate Cr toxicity. However, limited information is documented regarding the combined use of PGPR and foliar Fe. Therefore, the current study was conducted to screen Cr tolerant PGPR and examine effect of foliar Fe with and without Cr tolerant PGPR under Cr toxicity (50 and 100 mg kg^-1) in maize (Zea mays) production. Out of 15, two Cr tolerant PGPR were screened, identified (Agrobacterium fabrum and Leclercia adecarboxylata) and inoculated with 500 μM Fe. Results confirmed that Agrobacterium fabrum + 500 μM Fe performed significantly best in improving dry weight of roots and shoot, plant height, roots and shoot length and plant leaves in maize under Cr toxicity. A significant increase in chlorophyll a (51.5%), b (55.1%) and total (32.5%) validated the effectiveness of A. fabrum + 500 μM Fe to alleviate Cr toxicity. Improvement in intake of N (64.7%), P (70.0 and 183.3%), K (53.8% and 3.40-fold) in leaves and N (25.6 and 122.2%), P (25.6 and 122.2%), K (33.3% and 97.3%) in roots of maize at Cr50 and Cr100 confirmed that combined application of A. fabrum with 500 μM Fe is a more efficacious approach for alleviation of Cr toxicity and fortification of Fe comparative to sole foliar application of 500 μM Fe.

Pediatric renal transplantation

Although the number of children with end-stage renal disease (ESRD) in need for renal transplantation is small compared with adults, the problem associated with renal transplant in children are numerous, varied, and often peculiar. Pre-emptive transplantation has recently been growing in popularity as it avoids many of the associated long-term complications of ESRD and dialysis. Changes in immunosuppression to more potent agents over the years will have affected transplant outcome; there is also evidence that tacrolimus is more effective than cyclosporine. This review will discuss the short- and long-term complications such as acute and chronic rejection, hypertension, infections, and malignancies as well as factors related to long-term graft function. Chronic allograft nephropathy is the leading cause of renal allograft loss in pediatric renal transplant recipients. It is likely that it reflects a combination of both immune and nonimmune injury occurring cumulatively over time so that the ultimate solution will rely on several approaches. Transplant and patient survival have shown a steady increase over the years. The major causes of death after transplantation are cardiovascular disease, infection and malignancy. Transplantation in special circumstances such as children with abnormal urinary tracts and children with diseases that have the potential to recur after transplantation will also be discussed in this review. Non-compliance with therapeutic regimen is a difficult problem to deal with and affects patients and families at all ages, but particularly so at adolescence. Growth may be severely impaired in children with ESRD which may result in major consequences on quality of life and self-esteem; a better height attainment at transplantation is recognized as one of the most important factors in final height achievement. Although pediatric kidney transplantation is active in some parts of many developing countries, it is still inactive in many others and mostly relying on living donors. The lacking deceased programs in most of these countries is one of the main issues to be addressed to adequately respond to organ shortage. In conclusion, transplantation is currently the best option for children with ESRD. Although improvement in immunosuppression demonstrated excellent results and has led to greater 1-year graft survival rates, chronic graft loss remains relatively unchanged and opportunistic infectious complications remain a problem.

Current challenges of organ donation programs in syria

BACKGROUND

Renal transplantation is the optimal treatment for the majority of patients with end-stage renal disease.

OBJECTIVE

To examine the donor characteristics of kidney transplants in Syria and the impact of national Syrian legislation on the evolution of kidney transplantation activities in the private and public sectors.

METHODS

Available data on all kidney transplants performed in Syria over the last 2 decades was retrospectively analyzed to assess the characteristics of kidney donors and recipients with a focus upon transplants since 2003.

RESULTS

The kidney transplant rate has increased from 7 kidney transplants per million populations in 2002 to more than 17 in 2007. In the meantime, a substantial decline in the rate of kidney transplantation performed on Syrian nationals abroad was observed from 65% of all kidney transplantations in 1998 to less than 2% in 2007. Despite the prohibition to buy a kidney in Syria, vendors had found ways to sell their kidneys through disreputable brokers. Potential related donors were not inclined to donate kidneys to their relatives as long as kidneys could be bought from a non-related donor. By 2008, the percent of related donors in private sector represented only 8% of all donors, as compared to 50% in public hospitals. Consequently, in January 2008, the government of Syria issued a pronouncement restricting kidney transplantation to the public sector with a new national regulatory oversight of transplantation practices. Since this 2008 Administrative Order was promulgated, the kidney transplant rate in public hospitals has substantially increased by 55% with the establishment of new public transplant centers in the 3 largest cities in Syria.

CONCLUSION

The recommendations of the Istanbul Declaration and the Revised Guiding Principles of the World Health Organization have yet to be implemented in Syria but the expansion of kidney transplants in the public sector is an important initial step for initiating a deceased organ donation program as an essential component of a comprehensive approach to the problem of the organ shortage.

Dermal absorption of isopropyl alcohol from a commercial hand rub: implications for its use in hand decontamination

Isopropyl alcohol-containing hand rubs are widely used in healthcare for hand decontamination. Ten healthy adult volunteers applied a commercially available isopropyl alcohol-containing hand rub to their hands every 10 min over a 4 h period. Blood isopropyl alcohol levels were measured at the beginning and end of the study. At the end of the study, measurable blood isopropyl alcohol levels (range 0.5-1.8 mg/l) were recorded in nine subjects. We confirmed that isopropyl alcohol could be absorbed through the intact skin of adult humans. The social and medical implications are discussed.

Corticotropin-releasing hormone binding to the syncytiotrophoblast membranes

The human placenta secretes large amounts of corticotropin-releasing hormone (CRH) which was thought to exert a paracrine action in the placenta. We have recently characterized high-affinity binding sites for CRH in the human placenta. However, our studies utilized whole placental membranes, which did not identify the site of binding of CRH in the plasma membrane. In this study we investigated the characteristics of CRH binding to purified mother-facing, brush border membranes (BBM) and fetus-facing, basal plasma membranes (BPM) of the syncytiotrophoblast. The two membranes were separated by a series of differential and density-gradient centrifugations. The purity of the membranes was determined by measuring alkaline phosphatase, as a marker of BBM and Na+/K+ATPase as a marker of BPM. Each membrane showed specific and high-affinity binding. Scatchard analysis revealed a high-affinity binding site for CRH with Kd of 1.0 +/- 0.15 and 1.3 +/- 0.176 for BBM and BPM, respectively. The maximal number of binding sites was significantly different (P < 0.01) in the two plasma membranes: Bmax of 79 +/- 6.4 fmol/mg protein for BBM and 23 +/- 3.9 fmol/mg protein for BPM. Both the mother-facing and fetus-facing membranes of the syncytiotrophoblast contain binding proteins for CRH, with significantly more binding sites on the mother-facing membranes. The functional consequences of CRH binding could be different for the two polar membranes due to differential localization of second messenger systems between the two membrane types. It is proposed that partial purification of BBM and BPM provides a better system to study CRH action in the placenta, than whole placental membrane preparations.

Inhibition of farnesyltransferase with A-176120, a novel and potent farnesyl pyrophosphate analogue

Farnesylation of Ras is required for its transforming activity in human cancer and the reaction is catalysed by the enzyme farnesyltransferase. Recently, we discovered a novel chemical series of potent farnesyl pyrophosphate (FPP) analogues which selectively inhibited farnesyltransferase. Our most potent compound to date in this series, A-176120, selectively inhibited farnesyltransferase activity (IC(50) 1.2+/-0.3 nM) over the closely related enzymes geranylgeranyltransferase I (GGTaseI) (IC(50) 423+/-1.8 nM), geranylgeranyltransferase II (GGTaseII) (IC(50) 3000 nM) and squalene synthase (SSase) (IC(50)>10000 nM). A-176120 inhibited ras processing in H-ras-transformed NIH3T3 cells and HCT116 K-ras-mutated cells (ED(50) 1.6 and 0.5 microM, respectively). The anti-angiogenic potential of A-176120 was demonstrated by a decrease in Ras processing, cell proliferation and capillary structure formation of human umbilical vein endothelial cells (HUVEC), and a decrease in the secretion of vascular endothelial growth factor (VEGF) from HCT116 cells. In vivo, A-176120 reduced H-ras NIH3T3 tumour growth and extended the lifespan of nude mice inoculated with H- or K-ras-transformed NIH3T3 cells. A-176120 also had an additive effect in combination with cyclophosphamide in nude mice inoculated with K-ras NIH3T3 transformed cells. Overall, our results demonstrate that A-176120 is a potent FPP mimetic with both antitumour and anti-angiogenic properties.

Discovery of a series of cyclohexylethylamine-containing protein farnesyltransferase inhibitors exhibiting potent cellular activity

Synthesis of a library of secondary benzylic amines based on the Sebti-Hamilton type peptidomimetic farnesyltransferase (FTase) inhibitor FTI-276 (1) led to the identification of 6 as a potent enzyme inhibitor (IC(50) of 8 nM) which lacked the problematic thiol residue which had been a common theme in many of the more important FTase inhibitors reported to date. It has previously been disclosed that addition of o-tolyl substitution to FTase inhibitors of the general description 2 had a salutary effect on both FTase inhibition and inhibition of Ras prenylation in whole cells. Combination of these two observations led us to synthesize 7, a potent FTase inhibitor which displayed an IC(50) of 0.16 nM for in vitro inhibition of FTase and an EC(50) of 190 nM for inhibition of whole cell Ras prenylation. Modification of 7 by classical medicinal chemistry led to the discovery of a series of potent FTase inhibitors, culminating in the identification of 25 which exhibited an IC(50) of 0.20 nM and an EC(50) of 4.4 nM. In vivo tests in a nude mouse xenograft model of human pancreatic cancer (MiaPaCa cells) showed that oral dosing of 25 gave rise to impressive attenuation of the growth of this aggressive tumor cell line.

Second-generation peptidomimetic inhibitors of protein farnesyltransferase demonstrating improved cellular potency and significant in vivo efficacy

The synthesis and evaluation of analogues of previously reported farnesyltransferase inhibitors, pyridyl benzyl ether 3 and pyridylbenzylamine 4, are described. Substitution of 3 at the 5-position of the core aryl ring resulted in inhibitors of equal or less potency against the enzyme and decreased efficacy in a cellular assay against Ras processing by the enzyme. Substitution of 4 at the benzyl nitrogen yielded 26, which showed improved efficacy and potency and yet presented a poor pharmacokinetic profile. Further modification afforded 30, which demonstrated a dramatically improved pharmacokinetic profile. Compounds 26 and 29 demonstrated significant in vivo efficacy in nude mice inoculated with MiaPaCa-2, a human pancreatic tumor-derived cell line.

Potent and orally bioavailable noncysteine-containing inhibitors of protein farnesyltransferase

Potent and orally bioavailable nonthiol-containing inhibitors of protein farnesyltransferase are described. Oral bioavailability was achieved by replacement of the pyridyl ether moiety of 1 with a 2-substituted furan ether to give 4. Potency was regained with 2,5-disubstituted furan ethers while maintaining the bioavailability inherent in 4. p-Chlorophenylfuran ether 24 is 0.7 nM in vitro (FTase) and is 32% bioavailable in the mouse, 30% bioavailable in rats, and 21% bioavailable in dogs.

Potent inhibitors of protein farnesyltransferase: heteroarenes as cysteine replacements

Synthesis and biological evaluation of heteroarenes as reduced cysteine replacements are described. Of the heteroaryl groups examined with respect to FT inhibitor FTI-276 (1), pyridyl was the replacement found to be most effective. Substitutions at C4 of the pyridyl moiety did not affect the in vitro activity. Compound 9a was found to have moderate in vivo bioavailability.

Potent and selective non-cysteine-containing inhibitors of protein farnesyltransferase

Potent and selective non-thiol-containing inhibitors of protein farnesyltransferase are described. FTI-276 (1) was transformed into pyridyl ether analogue 19. The potency of pyridyl ether 19 was improved by modification of the biphenyl core to that of an o-tolyl substituted biphenyl core to give 29. In addition to 0.4 nM in vitro potency, 29 displayed 350 nM potency in whole cells as the parent carboxylic acid. The o-tolyl biphenyl core dramatically and unexpectedly enhanced the potency of other compounds as exemplified by 46, 47, 48, and 49.

Endothelin receptor in benign prostatic hyperplastic cells. Binding and functional studies

Endothelins (ETs) are 21-amino acid peptides that bind to membrane receptors to initiate pathophysiological effects. This report characterizes ET receptors in benign prostatic hyperplasia-1 (BPH-1) cells, a prostate cell line isolated from a specimen of a 60-yr-old man with benign prostatic hyperplasia. [(125)I]ET-1 or -3 binding was of high affinity, with B(max) and K(d) values of 48 fmol/1 x 10(6) cells and 0.16 nM for ET-1, and 2.9 fmol/1 x 10(6) cells and 0.033 nM for ET-3, respectively. ET-1, ET-3, FR139317, Ro 46-2005, and IRL1620 inhibited [(125)I]ET-1 binding to these cells with IC50 values of 0.22, 186, 0.20, 52.8, and 772.3 nM, respectively. Reverse transcription-polymerase chain reaction confirmed that BPH-1 cells expressed more ET(A) than ET(B) receptors. ET-1 did not have any effect on arachidonic acid release, but caused a modest stimulation of phosphatidylinositol hydrolysis, and induced a prominent, sustained elevation in intracellular Ca2+ concentrations. The functional effects of ET-1 were completely inhibited by the ET(A)-selective antagonists FR139317 and A-127722, suggesting that the effects were mediated by the ET(A) receptor. These results suggest that ET may play functional roles in benign prostatic hyperplasia.

Apoptotic program is initiated but not completed in LNCaP cells in response to growth in charcoal-stripped media

BACKGROUND

Morphological, proliferative, and genetic changes were studied in androgen-responsive LNCaP cells in response to growth in charcoal-stripped (CS) media.

METHODS AND RESULTS

Within 5 days of treatment, there were dramatic changes in the morphology and organization of LNCaP cells. The cells unclumped and acquired a distinct neuronal-like appearance with small cell bodies and multiple long, thin processes. Despite this appearance, the cells stained negative to monoclonal antibodies to neuronal markers such as microtubule-associated protein-2 (MAP-2) and glial fibrillary acidic protein (GFAP). In situ end-labeling assay indicated that the number of cells showing signs of apoptosis (DNA fragmentation) increased dramatically in CS media compared to the control. However, ultrastructural changes and the fragmented DNA ladder that are used to define apoptosis were not observed. Instead of cell death, the cells became cytostatic, which can be reversed, although not completely, by exogeneous addition of dihydrotestosterone in a dose-dependent manner. Presence of mRNA of several genes involved in the apoptotic process, i.e., Bcl-2, Bcl-X, ICE, Ich-1, and DAD-1, was studied in response to normal and CS media. We detected mRNA of Bcl-2, Bcl-XL, Bcl-XS, Ich-1L and DAD-1, while ICE and Ich-1S were not expressed in LNCaP cells.

CONCLUSIONS

This suggests that certain signals that may be essential for complete execution of the apoptotic program may be missing in this in vitro model. This may explain our observation that the growth of LNCaP cells in CS media does not fully mimic castration-mediated regression of the prostate gland in vivo.

Induction of apoptosis in prostatic tumor cell line DU145 by staurosporine, a potent inhibitor of protein kinases

We are interested in studying the possibility of modulating prostatic cell growth by manipulating apoptosis. Here we show that 1 microM staurosporine (STS) induces a human androgen-independent prostatic tumor cell line, DU145, to undergo dramatic changes in morphology and results in programmed cell death. Several genes involved in apoptosis were analyzed for expression in STS-treated and untreated DU145 cells. It was observed that these genes were differentially regulated. The expression level of bcl-2, bcl-xL, Ich-1L remains unchanged in treated and untreated cells. On the other hand, DAD1 and interleukin-1 beta-converting enzyme (ICE) were downregulated while bcl-xs and Ich-1s were upregulated. By blocking bcl-2 gene expression using antisense oligonucleotides, it was determined that the anti-bcl-2 oligonucleotides have no effect on the proliferation of DU145 or STS-treated DU145 cells. These results demonstrate that programmed cell death can be induced in an androgen-independent prostatic cancer cell line and BCL-2 was found not to play an important role in preventing STS-induced apoptosis in the DU145 cell line.

Combinatorial interaction of human bcl-2 related proteins: mapping of regions important for bcl-2/bcl-x-s interaction

Human bcl-2 family of genes including bcl-2, bcl-x-l, bcl-x-s, and bax has been shown to be functionally involved in apoptosis. We applied a yeast two-hybrid system to demonstrate that bcl-2, bcl-x-l, bcl-x-s, and bax proteins can interact with each other directly. All bcl-2 family members except bax were shown to be capable of homo-interactions. By using deletion and point mutations, the interaction domains for bcl-2 and bcl-x-s were elucidated. The BH1 domain and the membrane anchoring region at the C-terminal half of the bcl-2 protein are required for its interaction with bcl-x-s. On the other hand, the N-terminal region consisting of codons 24 to 78 of bcl-x-s interacts with bcl-2.