bluuebunny/crossref_metadata_2025 huggingface dataset:
Disabled infectious single cycle herpes simplex virus (DISC‐HSV) is a candidate vector system for gene delivery/expression of GM‐CSF in human prostate cancer therapy
Authors: Parkinson Richard J. , Mian Shahid , Bishop Michael C. , Gray Trevor , Li Geng , McArdle Stephanie E.B. , Ali Selman , Rees Robert C.
Published: May 2003

BACKGROUND

DISC‐HSV is a replication incompetent herpes simplex virus that is a highly efficient vector for the transduction of genes in vivo and in vitro. We examine the ability of DISC‐HSV to infect human prostate cancer cell‐lines and xenograft tumor models, and induce expression of reporter and therapeutic cytokine genes.

METHODS

Infection was confirmed by cellular staining for the beta‐galactosidase reporter gene product, and by EM. Human GM‐CSF production following DISC‐hGMCSF infection was measured using ELISA. The metabolic activity of infected cells was determined by NADP/NADPH assay. Cell death was estimated by cell‐cycle analysis using flow cytometry with propidium iodide staining.

RESULTS

Infection of DU145, PC3 and LNCaP cells with DISC‐HSV was dose dependent. Cells infected with DISC‐hGM‐CSF released significant levels of hGM‐CSF for 3 days. NADP/NADPH assay suggested that infected cells continued to be metabolically active for 3 days post‐infection, which was consistent with flow cytometry findings that cell death did not occur within 7 days of infection. Tumor xenografts injected with DISC‐HSV expressed beta‐galactosidase, and intracellular viral particles were demonstrated using EM.

CONCLUSIONS

We have previously reported the rejection of established tumors following intra‐tumoral injection of DISC‐GMCSF. This study demonstrates the ability of DISC‐HSV to infect prostate cancer and express GMCSF at significant levels. We suggest that prostate cancer is a potential target for therapy using DISC‐HSV containing GM‐CSF. Prostate 56: 65–73, 2003. © 2003 Wiley‐Liss, Inc.
Prostate‐specific antigen (PSA) protein does not affect growth of prostate cancer cells in vitro or prostate cancer xenografts in vivo
Authors: Denmeade Samuel R. , Litvinov Ivan , Sokoll Lori J. , Lilja Hans , Isaacs John T.
Published: May 2003

Background

Prostate‐specific antigen (PSA) is produced in high amounts by normal and malignant prostate cancer cells. PSA is a serine protease with substrates that include semenogelin I and II, insulin‐like growth factor binding protein 3, fibronectin, and laminin. PSA, via its enzymatic activity, may play a role in growth, invasion, and metastasis of prostate cancer cells. Recent data also suggest that the PSA protein itself, independent of enzymatic activity, may also function as an endothelial cell‐specific inhibitor of angiogenesis.

Methods

Human (PC3, DU145) and rat (AT2, AT6) prostate cancer cell lines were transfected with the full PSA gene encoding preproPSA protein. PSA‐producing clones of each cell line were selected and the amount of enzymatically active PSA produced by each cell line determined using a PSA‐specific fluorescent peptide substrate. In vitro and in vivo growth characteristics of PSA‐producing transfectants were compared to neomycin controls and wild type cells.

Results

All selected clones produced and secreted PSA (5–120 ng/ml/105 cells). None of the PSA‐transfected cell lines produced detectable amounts of enzymatically active PSA. Production of enzymatically inactive PSA by prostate cancer cell lines did not alter growth kinetics in vitro. PSA‐producing xenograft doubling times in vivo were similar to neomycin controls and wild type.

Conclusion

Although recent reports suggest the PSA protein itself may be antiangiogenic, our results demonstrate that production of PSA protein by prostate cancer cells does not significantly alter growth in vitro or in vivo. Prostate 56: 45–53, 2003. © 2003 Wiley‐Liss, Inc.
Luteinizing hormone β polymorphism and risk of familial and sporadic prostate cancer
Authors: Elkins David A. , Yokomizo Akira , Thibodeau Stephen N. , J. Schaid Daniel , Cunningham Julie M. , Marks Angela , Christensen Eric , McDonnell Shannon K. , Slager Susan , J. Peterson Brett , J. Jacobsen Steven , R. Cerhan James , L. Blute Michael , J. Tindall Donald , Liu Wanguo
Published: May 2003

Background

Circulating testosterone plays an important role in maintenance and growth of prostate cells. Luteinizing hormone (LH), secreted from the anterior pituitary, signals testicular Leydig cells to secrete testosterone. A genetic variant of the LH‐β protein, LH‐βV, exists in up to 40% of Caucasians and is more bioactive than the wild‐type protein. We hypothesized that genetically determined variation in LH function might affect susceptibility to prostate cancer via altered testosterone secretion.

Methods

We determined the frequency of the LH‐βV polymorphism (two linked polymorphisms: Trp8 → Arg and Ile15 → Thr) in familial prostate cancer patients (n = 446), in sporadic prostate cancer patients (n = 388), and in population‐based controls without prostate cancer (n = 510) to assess the role of this polymorphism in susceptibility to prostate cancer.

Results

A higher frequency of this variant genotype (LH‐βV: Arg8/Thr15) was observed in familial prostate cancer patients (18.6%) than in controls (13.7%), and after taking into account the correlation of the familial cases and adjusting for age and body mass index (BMI), there was a weak positive association between the variant LH‐β genotype, and risk of familial prostate cancer (OR = 1.29; 95% CI 0.96–1.75). The sporadic case group was also slightly more likely to have a variant genotype (15.2%) compared to the controls (13.7%), and after adjustment for age and BMI, a similar association with this variant was found (OR = 1.33; 95% CI 0.86–02.07). Surgical cases showed a slightly stronger association for the variant LH‐β genotype compared to non‐surgical cases, but among the surgical cases there was little variability in risk across nodal status, stage, and tumor grade.

Conclusions

These data are consistent with the hypothesis that the LH‐β variant is a weak risk factor for prostate cancer. Prostate 56: 30–36, 2003. © 2003 Wiley‐Liss, Inc.
Development of a quantitative RT‐PCR method to study 5α‐reductase mRNA isozymes in rat prostate in different androgen status
Authors: Torres Jesus M. , Ruiz Estrella , Ortega Esperanza
Published: May 2003

BACKGROUND

The incidence of prostate cancer (PCa) and benign prostatic hypertrophy (BPH) continues to rise in the Western world. The development and growth of the prostate gland depends on androgen stimulation. Dihydrotestosterone (DHT) is the primary androgen responsible for prostate development and also for the pathogenesis of benign prostatic hyperplasia (BPH). DHT is synthesized in prostate from circulating testosterone (T) through the action of 5α‐Reductase (5α‐R) (EC 1.3.99.5), which occurs as two isozymes, type‐1 and type‐2. Both types are expressed in the prostate: type‐2 isozyme is predominantly expressed in prostate and is implicated in BPH and PCa; type‐1 isozyme is also increased in some prostatic adenocarcinomas. In recent years, various inhibitors of type‐2 isozyme or of both type‐1 and type‐2 isozyme have been used in prostatic diseases.

METHODS

We present the first published measurements of mRNA levels of steroid 5α‐R isozymes in the ventral prostate of rats of different androgen status. We used a novel method that combines the high specificity of competitive PCR with the sensitivity of laser‐induced capillary electrophoresis (LIF‐CE).

RESULTS

We demonstrated that T and DHT androgens control the expression of both 5α‐R isozymes in rat prostrate.

CONCLUSIONS

This approach could be of great value for the study of prostate diseases in humans and would allow study at the transcriptional level of the effects of drugs that inhibit either or both of these isozymes. Prostate 56: 74–79, 2003. © 2003 Wiley‐Liss, Inc.
Insulin‐like growth factor binding protein‐related protein 1 (IGFBP‐rP1/mac 25) is reduced in human prostate cancer and is inversely related to tumor volume and proliferation index in Lucap 23.12 xenografts
Authors: Tennant Marie K. , Vessella Robert L. , Sprenger Cynthia C. , Sikes Robert A. , Hwa Vivian , Baker Laura D. , Plymate Stephen R.
Published: May 2003

BACKGROUND

In the prostate, insulin‐like growth factor binding protein‐related protein‐1 (IGFBP‐rP1/mac 25) appears to be decreased in cancer. Likewise, mice injected with prostate cells over‐expressing IGFBP‐rP1/mac 25 showed decreased tumor formation and tumor volume.

METHODS

Immunohistochemistry was used to determine the presence of IGFBP‐rP1/mac 25 in human prostate tissue and in LuCaP 23.12 prostate cancer xenografts.

RESULTS

Immunoreactivity for IGFBP‐rP1/mac 25 was detected in the cytoplasm and nuclei of benign prostate epithelium. Cancer cells also stained but the level of intensity was less than that observed in benign epithelium (P < 0.05). Within the stroma, peripheral nerves, and endothelial vessels reacted with IGFBP‐rP1/mac 25 antibodies. IGFBP‐rP1/mac 25 was also observed in the nuclei of LuCaP 23.12 cells. LuCaP xenografts with smaller tumor volumes demonstrated more staining, and larger tumor volumes had less staining (P = 0.0033, R = 0.610). There was also a significant inverse correlation between IGFBP‐rP1/mac 25 levels in LuCaP 23.12 cells and the proliferative index, measured by percent of cells staining for 5‐bromo‐2′‐deoxyuridine (Br‐dU) (P = 0.0045, R = 0.594).

CONCLUSIONS

IGFBP‐rP1/mac 25 is present in normal prostate epithelium and is decreased in human prostate malignancy and higher IGFBP‐rP1/mac 25 levels are associated with reduced tumor growth. Prostate 56: 115–122, 2003. © 2003 Wiley‐Liss, Inc.
Evaluation of SRD5A2 sequence variants in susceptibility to hereditary and sporadic prostate cancer
Authors: Chang Bao‐li , Zheng S. Lilly , Isaacs Sarah D. , Turner Aubrey R. , Bleecker Eugene R. , Walsh Patrick C. , Meyers Deborah A. , Isaacs William B. , Xu Jianfeng
Published: May 2003

Background

The 5 alpha‐reductase type II (SRD5A2) catalyzes the conversion of testosterone into the more potent androgen, dihydrotestosterone (DHT), and is thus believed to be the key enzyme for the control of intracellular DHT level in the prostate. Several single nucleotide polymorphisms (SNPs) in the SRD5A2 gene have been found to alter enzymatic activities and were associated with prostate cancer risk or clinical features in several case–control studies. However, the role of SRD5A2 sequence variants in the susceptibility to hereditary prostate cancer (HPC) has not been evaluated to date.

Methods

Three SNPs in the SRD5A2 gene (A49T, V89L, and C682G) and two microsatellite markers near SRD5A2 were genotyped in 159 HPC families to assess their linkage to prostate cancer. In addition, the three SNPs were also genotyped in 245 sporadic cases and 222 unaffected controls to assess their association with hereditary and sporadic prostate cancer.

Results

Weak evidence for linkage in the SRD5A2 chromosomal region was observed in the 159 HPC families (HLOD = 0.87, P = 0.04). Stronger evidence for linkage was observed in Caucasian families (HLOD = 1.10, P = 0.02). When stratified by the SNP A49T, no significant evidence for linkage was observed in families with or without the “T” allele. Similarly, family‐based association tests failed to observe significant over‐transmission of any risk alleles of SNPs A49T, V89L, and C682G to affected offspring. Finally, no significant differences in the distributions of SNPs A49T, V89L, and C682G were found among the HPC probands, sporadic cases, and controls.

Conclusions

Polymorphisms of SRD5A2 are unlikely to significantly increase susceptibility to hereditary or sporadic prostate cancer in the study populations. Prostate 56: 37–44, 2003. © 2003 Wiley‐Liss, Inc.
Anti‐androgenic action by red clover‐derived dietary isoflavones reduces non‐malignant prostate enlargement in aromatase knockout (arko) mice
Authors: Jarred Renea A. , McPherson Stephen J. , Jones Margaret E.E. , Simpson Evan R. , Risbridger Gail P.
Published: May 2003

Background

Red clover (RC)‐derived dietary isoflavones have been implicated as potential preventative agents for the development and prevalence of non‐malignant prostate diseases. This study investigated whether dietary isoflavones inhibit prostate growth in vivo in the aromatase knock‐out (ArKO) mouse that exhibits lifelong elevation of androgens leading to prostate enlargement.

Methods

Adult (11‐week‐old) wild‐type (WT) and ArKO mice were fed on protein matched isoflavones free (IF) and RC (isoflavone rich) diets for 28 days. Individual prostate lobes and testes were weighed and collected for histological analysis and serum androgens were measured. Responses were compared to castration and estrogen administration to ArKO mice to determine the mechanism of action.

Results

ArKO mice fed on IF diet exhibited enlarged prostate lobes and elevated serum androgens compared to WT mice. Following 28 days of RC diet, ArKO VP, AP, and SV weights were reduced to WT weights, although testis and body weights remained unaltered. Stereological analysis of VPs revealed a reduction in all components of the tissue, particularly the lumen. The RC diet reduced ArKO serum testosterone and dihydrotestosterone to WT levels. In comparison to castration and estrogen administration, the dietary isoflavones were shown to be anti‐androgenic rather than weakly estrogenic, mimicking responses observed in the castrated ArKO, rather than estrogen treated ArKOs.

Conclusions

This study demonstrates that RC‐derived isoflavones have a significant effect on prostatic growth, and are capable of reducing the enlarged non‐malignant prostate phenotype of the adult ArKO mouse, by acting as anti‐androgenic agents rather than weak estrogenic substances. Prostate 56: 54–64, 2003. © 2003 Wiley‐Liss, Inc.
Possible mechanism of dexamethasone therapy for prostate cancer: Suppression of circulating level of interleukin‐6
Authors: Akakura Koichiro , Suzuki Hiroyoshi , Ueda Takeshi , Komiya Akira , Ichikawa Tomohiko , Igarashi Tatsuo , Ito Haruo
Published: May 2003

BACKGROUND

Glucocorticoids may have favorable effects on prostate cancer patients showing clinical and/or biochemical failure after androgen ablation. The efficacy and mechanisms of dexamethasone therapy as possible alternative endocrine therapy were investigated.

METHODS

Twenty five patients with prostate cancer treated by androgen ablation and showing a steady increase in serum prostate specific antigen (PSA) were treated with low‐dose dexamethasone.

RESULTS

Of 25 patients, 11 demonstrated 50% or more decline of serum PSA and 9 showed improvement of pain on dexamethasone therapy. Of 8 patients who responded to dexamethasone thearpy, 5 had 80% or more decrease in serum interleukin‐6 (IL‐6). In contrast, none of 8 non‐responders showed remarkable IL‐6 suppression. Response of PSA was not correlated to the changes in serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, or androstendione.

CONCLUSIONS

Significant suppression of serum IL‐6, probably through inhibition of androgen‐independent activation of androgen receptor, may be one of the mechanisms for the effect of dexamethasone therapy in prostate cancer patients with progressive disease. Prostate 56: 106–109, 2003. © 2003 Wiley‐Liss, Inc.
A novel method of generating prostate cancer metastases from orthotopic implants
Authors: Corey Eva , Quinn Janna E. , Vessella Robert L.
Published: May 2003

BACKGROUND

Spontaneous metastasis following implantation at the orthotopic site is a highly desired feature in prostate cancer (CaP) models, since it would enable studies of mechanisms associated with tumor cell dissemination.

METHODS

LuCaP 23.8 and LuCaP 35, hormone‐sensitive CaP xenografts that express PSA and the wild‐type androgen receptor, were grown orthotopically in SCID mice. When tumor volumes reached ∼250–500 mg, primary tumors were removed to allow micrometastases to grow.

RESULTS

Using this procedure we generated macroscopic metastases (>20 mg) in 71% (LuCaP 23.8) and 100% (LuCaP 35) of animals, respectively.

CONCLUSIONS

These models may be used to evaluate new treatment modalities and study mechanisms associated with development of metastases. Prostate 56: 110–114, 2003. © 2003 Wiley‐Liss, Inc.
Prediction of extraprostatic cancer by prostate specific antigen density, endorectal MRI, and biopsy Gleason score in clinically localized prostate cancer
Authors: Horiguchi Akio , Nakashima Jun , Horiguchi Yutaka , Nakagawa Ken , Oya Mototsugu , Ohigashi Takashi , Marumo Ken , Murai Masaru
Published: May 2003

Backgrounds

The present study was designed to identify the preoperative parameters, including PSA‐based parameters, and endorectal MRI, predictive of pathological stage in males who underwent radical prostatectomy.

Methods

We studied 114 patients who underwent radical retropubic prostatectomy and pelvic lymphadenectomy for clinically localized prostate cancer. Clinical stage was assessed by DRE, pelvic CT scan, endorectal MRI, and bone scan. The correlation between the preoperative parameters, including PSA‐based parameters, clinical stage, and histological findings of biopsy specimens, and the pathological stage was analyzed. Logistic regression analysis was performed to identify a significant set of independent predictors for local extent of disease.

Results

Seventy‐six (66.6%) patients had organ confined cancer and 38 (33.4%) patients had extraprostatic cancer. Of the 38 patients with extraprostatic cancer, four had seminal vesicle involvement, while, none had pelvic lymph node involvement. Biopsy Gleason score, PSA, PSA‐α1‐antichymotrypsin (PSA‐ACT), PSA‐density (PSAD), PSA‐transition zone density, PSA‐ACT density, and PSA‐ACT transition zone (TZ) density were significantly higher and percent free PSA was lower in the patients with organ confined cancer than those with extraprostatic cancer (P < 0.01). PSAD showed the largest area under the ROC curve (AUC) among those parameters (AUC = 0.732). Sixty‐eight (74.7%) of 91 patients with T2 on endorectal MRI had organ confined cancer, while 15 (65.2%) of 23 patients with T3 had extraprostatic cancer (P < 0.01). Multivariate logistic regression analysis indicated that Gleason score (≥7 vs. ≤6), endorectal MRI findings, and PSAD were significant predictors of extraprostatic cancer (P < 0.01).

Conclusions

The present study demonstrated that preoperative PSAD was the most valuable predictor among PSA‐based parameters for extraprostatic disease in patients with clinically localized prostate cancer. The combination of PSAD, endorectal MRI findings, and biopsy Gleason score can provide additional information for selecting appropriate candidates for radical prostatectomy. Prostate 56: 23–29, 2003. © 2003 Wiley‐Liss, Inc.
ErbB1 and prostate cancer: ErbB1 activity is essential for androgen‐induced proliferation and protection from the apoptotic effects of LY294002
Authors: Tørring Niels , Dagnæs‐Hansen Frederik , Sørensen Boe Sandahl , Nexø Ebba , Hynes Nancy E.
Published: May 2003

Background

Androgens play a critical role in proliferation and survival of prostate cancer cells, but the mechanisms leading to these effects are poorly understood. ErbB receptor tyrosine kinases have been implicated in the development of prostate cancer.

Methods

We examined the interaction between the ErbB receptors and androgens using the LNCaP androgen‐sensitive prostate tumor model.

Results

In the absence of androgens, the cells have low levels of ErbB1 and relatively high levels of ErbB2. Addition of androgens to the medium reversed the ratio; ErbB1 levels rose and ErbB2 levels dropped in response to treatment with the synthetic hormone, R1881. Expression of ErbB activating ligands was found to be constitutive and androgen‐independent. The androgen‐induced proliferation of LNCaP cells was completely inhibited by the addition of the small molecule ErbB1 tyrosine kinase inhibitors CGP59326 and the bispecific inhibitor (PKI166) for ErbB1 and ErbB2 to the culture medium. Furthermore, in the absence of androgens the relatively low proliferative level was further significantly reduced in the presence of CGP59326. Inhibition of PI3K activity by LY294002 led to induction of apoptosis in androgen‐deprived LNCaP cells. Androgen‐mediated rescue from LY294002‐induced apoptosis was inhibited by addition of CGP59326 to the cells.

Conclusions

These results suggest a model whereby androgens promote an increase in the activity of the epidermal growth factor (EGF)‐network by increasing ErbB1 levels, and this activity of is essential for androgen‐induced proliferation and survival of the prostate cancer LNCaP cell line. Prostate 56: 142–149, 2003. © 2003 Wiley‐Liss, Inc.
Three immunoassays based on monoclonal antibodies specific for prostate specific antigen (PSA), α‐1‐antichymotrypsin (ACT), and the PSA–ACT complex
Authors: Wan X. Steven , Xu Y. Anne , Ware Jeffrey H. , Kennedy Ann R.
Published: May 2003

BACKGROUND

Prostate specific antigen (PSA) has been widely used as a biomarker for the screening and diagnosis of prostate cancer. PSA in serum predominantly exists as a complex with α‐1‐antichymotrypsin (ACT), and measurement of free PSA and the PSA–ACT complex may improve the utility of the serum PSA assay for differential diagnosis of prostate cancer and non‐malignant prostate diseases, such as benign prostatic hyperplasia (BPH).

METHODS

Monoclonal antibodies (MAbs) against PSA, ACT, and the PSA–ACT complex were produced by immunizing mice with an incubated mixture of PSA and ACT, and characterized by Western blot analyses and several enzyme‐linked immunosorbant assay (ELISA) methods.

RESULTS

The MAbs produced in this study are capable of distinguishing the PSA–ACT complex from free PSA and ACT. Four MAbs have been selected and utilized to construct three ELISA systems for the separate measurements of free PSA, the PSA–ACT complex, and total PSA.

CONCLUSIONS

The three PSA assay systems developed in this study can specifically measure free PSA, total PSA, and the PSA–ACT complex with equal molar sensitivity. It is expected that these PSA assay systems could be useful in the diagnosis of prostate cancer. Prostate 56: 131–141, 2003. © 2003 Wiley‐Liss, Inc.
Glutathione S‐transferase pi is upregulated in the stromal compartment of hormone independent prostate cancer
Authors: Li Ming , Ittmann Michael M. , Rowley David R. , Knowlton Anne A. , Vaid Ajula K. , Epner Daniel E.
Published: May 2003

Background

Glutathione S‐transferase (GST) pi is a detoxifying enzyme abundant in normal prostate basal cells but only rarely expressed in prostate cancer cells. The current studies are the first to focus on GST pi in the stromal compartment of prostate tumors.

Methods

We employed immunohistochemical, immunofluorescence, and Western blot analysis to measure GST pi expression and subcellular localization in 21 primary and metastatic tumors from patients with hormone independent prostate cancer, as well as seven lymph node metastases and six prostatectomy specimens.

Results

GST pi was detectable in stromal cells in 17 of the 21 hormone independent prostate tumors. GST pi tissue distribution in hormone independent tumors coincided with vimentin staining, suggesting that GST pi is expressed by reactive fibroblasts and/or myofibroblasts.

Conclusions

The current results suggest that prostate cancer cells induce an injury response in the stroma during progression to hormone independence, which results in GST pi expression. Stromal GST pi may contribute to chemoresistence of advanced prostate cancer. Prostate 56: 98–105, 2003. © 2003 Wiley‐Liss, Inc.
Proteomic analysis of human prostasomes
Authors: Utleg Angelita G. , Yi Eugene C. , Xie Tao , Shannon Paul , White James T. , Goodlett David R. , Hood Leroy , Lin Biaoyang
Published: May 2003

BACKGROUND

Prostasomes are secretory particles in human seminal fluid. Other than a microscopic description of these secretory particles and an incomplete two–dimensional gel electrophoresis (2DE) study, little is known about the composition of proteins in prostasomes.

METHODS

We employed a direct iterative approach using Gas phase fractionation and microcapillary HPLC‐tandem mass spectrometry (μLC‐MS/MS) to catalogue the prostasome proteome.

RESULTS

We identified 139 proteins that can be divided into the following categories: (1) enzymes (33.8% of total), (2) transport/structural (19.4% of total), (3) GTP proteins (14.4% of total), (4) chaperone proteins (5.8% of total), (5) signal transduction proteins (17.3% of total), and (6) unannotated proteins (9.4% of total). A total of 128 of the 139 proteins have not previously been described as prostasomal.

CONCLUSIONS

The proteins identified can be used as reference dataset in future work comparing prostasome proteins between normal and pathological states such as prostate cancer, benign prostatic hyperplasia, prostatitis, and infertility. Prostate 56: 150–161, 2003. © 2003 Wiley‐Liss, Inc.
External Fixation for Surgical Treatment of a Mallet Finger
Authors: KALELI T. , OZTURK C. , ERSOZLU S.
Published: June 2003

A new surgical technique is described for the treatment of mallet finger deformity which involves the application of a mini external fixator across the distal interphalangeal joint and resection of a portion of the extensor mechanism. We reviewed 19 patients who were treated with this technique, at a mean follow-up period of 36 (range, 24–48) months. The mean extensor lag was 2° (range, −7° to 13°) and the mean flexion range was 70° (range, 20°–90°).
Marker-assisted estimation of quantitative genetic parameters in rainbow trout, Oncorhynchus mykiss
Authors: WILSON A. J. , McDONALD G. , MOGHADAM H. K. , HERBINGER C. M. , FERGUSON M. M.
Published: May 2003

Estimation of quantitative genetic parameters conventionally requires known pedigree structure. However, several methods have recently been developed to circumvent this requirement by inferring relationship structure from molecular marker data. Here, two such marker-assisted methodologies were used and compared in an aquaculture population of rainbow trout (Oncorhynchus mykiss). Firstly a regression-based model employing estimates of pairwise relatedness was applied, and secondly a Markov Chain Monte Carlo (MCMC) procedure was employed to reconstruct full-sibships and hence an explicit pedigree. While both methods were effective in detecting significant components of genetic variance and covariance for size and spawning time traits, the regression model resulted in estimates that were quantitatively unreliable, having both significant bias and low precision. This result can be largely attributed to poor performance of the pairwise relatedness estimator. In contrast, genetic parameters estimated from the reconstructed pedigree showed close agreement with ideal values obtained from the true pedigree. Although not significantly biased, parameters based on the reconstructed pedigree were underestimated relative to ideal values. This was due to the complex structure of the true pedigree in which high numbers of half-sibling relationships resulted in inaccurate partitioning of full-sibships, and additional unrecognized relatedness between families.
Hill–Robertson interference in Drosophila melanogaster: reply to Marais, Mouchiroud and Duret
Authors: KLIMAN RICHARD M. , HEY JODY
Published: May 2003

The usage of preferred codons in Drosophila melanogaster is reduced in regions of lower recombination. This is consistent with population genetics theory, whereby the effectiveness of selection on multiple targets is limited by stochastic effects caused by linkage. However, because the selectively preferred codons in D. melanogaster end in C or G, it has been argued that base-composition-biasing effects of recombination can account for the observed relationship between preferred codon usage and recombination rate (Marais et al., 2003). Here, we show that the correlation between base composition (of protein-coding and intron regions) and recombination rate holds only for lower values of the latter. This is consistent with a Hill–Robertson interference model and does not support a model whereby the entire effect of recombination on codon usage can be attributed to its potential role in generating compositional bias.
Neutral effect of recombination on base composition in Drosophila
Authors: MARAIS GABRIEL , MOUCHIROUD DOMINIQUE , DURET LAURENT
Published: May 2003

Recombination is thought to have various evolutionary effects on genome evolution. In this study, we investigated the relationship between the base composition and recombination rate in the Drosophila melanogaster genome. Because of a current debate about the accuracy of the estimates of recombination rate in Drosophila, we used eight different measures of recombination rate from recent work. We confirmed that the G+C content of large introns and flanking regions is positively correlated with recombination rate, suggesting that recombination has a neutral effect on base composition in Drosophila. We also confirmed that this neutral effect of recombination is the main determinant of the correlation between synonymous codon usage bias and recombination rate in Drosophila.
Identification and characterization of t haplotypes in wild mice populations using molecular markers
Authors: DOD BARBARA , LITEL CATHY , MAKOUNDOU PATRICK , ORTH ANNIE , BOURSOT PIERRE
Published: May 2003

As part of a population genetics survey of the hybrid zone between mouse subspecies Mus musculus domesticus and M. m. musculus, we identified and characterized the t haplotypes in 1068 mice from 186 different populations in a 2500 km2 area in central Jutland. On the basis of two t-specific PCR markers, 130 mice possessed this haplotype. The allele frequencies at six microsatellites on the third and fourth chromosomal inversions of the t region were sufficiently different between t-bearing and non-t-bearing mice, and linkage disequilibria sufficiently marked on the t haplotype, to be able to reconstitute the genotype of most t haplotypes. A total of three frequent and 15 rarer haplotypes were identified. These haplotypes resemble each other more than they resemble a panel of known haplotypes from a wide range of geographical regions, except for tw73, which was also extracted from Jutland. The patterns of variation at the microsatellite loci suggest that the Jutland haplotypes were derived from a small number of haplotypes, followed by recombination between complementing haplotypes. Further evidence of recombination came from complementation tests that we performed, showing the lack of concordance between the degrees of complementation and of molecular resemblance between haplotypes. This study shows that it is possible to characterize the presence and variation of t haplotypes by a population genetics approach using simple molecular markers. However recombination between t haplotypes has occurred frequently enough to obscure the links between this variation and the biological properties of distortion and lethality of the haplotypes that originally colonized Jutland.
The EIM algorithm in the joint segregation analysis of quantitative traits
Authors: YUAN-MING ZHANG , JUN-YI GAI , YONG-HUA YANG
Published: May 2003

In this article, a new algorithm for obtaining the maximum likelihood estimators (MLEs) of parameters in the joint segregation analysis (JSA) of multiple generations of P1, F1, P2, F2 and F2[ratio ]3 (MG5) for quantitative traits was set up. Firstly, owing to the fact that the component variance of the heterogeneous genotype in F2[ratio ]3 included both the first-order genetic parameters (denoted by the means of distributions) and the second-order parameters, a simple closed form for the MLEs of the means of component distributions did not exist while the expectation and maximization (EM) algorithm was used. To simplify the estimation of parameters, the first partial derivative of the above variance on the mean in the sample log-likelihood function was omitted. However, this would be remedied by the iterated method. Then, variances of component distributions for segregating populations were partitioned into major-gene, polygenic and environmental variances so that the generally iterated formulae for estimating the means as well as polygenic and environmental variances of component distributions in the maximization step (M-step) of the EM algorithm were obtained. Therefore, the EM algorithm for estimating parameters in the JSA model for the MG5 was simplified. This is called the expectation and iterated maximization (EIM) algorithm. Finally, an example of the inheritance of the resistance of soybean to beanfly showed that the results of mixed inheritance analysis in this paper coincided with those in both Wang & Gai (2001) and Wei et al. (1989), so the EIM algorithm was appropriate.
Estimating allelic number and identity in state of QTLs in interconnected families
Authors: JANNINK JEAN-LUC , WU XIAO-LIN
Published: May 2003

When multiple related families derived from inbred lines are jointly analysed to detect quantitative trait loci (QTLs), the analysis should estimate allelic effects as accurately as possible and estimate the probability that different parents carry alleles that are identical in state. Analyses exist that assume that all parents carry unique alleles or that all parents but one carry the same allele. In practice, many configurations are possible that group different parents according to their identity-in-state condition at a putative QTL allele. Here, we propose a variable model Bayesian analysis that selects among possible identity-in-state configurations and jointly estimates the allelic effects of identical-in-state parents. We contrast this analysis with a fixed model analysis that estimates unique allelic effects for all parents. We analyse two simulated mating designs: an experimental design in which three inbred parents were crossed to generate two families of 150 doubled haploid lines; and a breeding design in which 20 inbred parents were crossed to generate 60 families of 20 doubled haploid lines, with each parent contributing to six families. In all cases where some parents were simulated to carry alleles of identical effect (that is, they were identical in state), the variable analysis estimated allelic effects with lower mean-squared error than the fixed analysis. The variable analysis showed that, unless each family contains many individuals (more than 100), there is insufficient information in DNA-marker and phenotypic data to determine with high probability the QTL allelic number.
Acetolactate synthase activity and chlorsulfuron sensitivity of gamma-irradiated lentil (Lens culinaris Medik.) cultivars
Authors: MALKAWI H. I. , AL-QURAAN N. A. , OWAIS W. M.
Published: May 2003

Lentil (Lens culinaris Medik.) cultivars (Jordan 1 and Jordan 2) were sensitized to chlorsulfuron herbicide. Both cultivars were subjected to three doses of gamma-irradiation (90, 100 and 110 Gray) to develop plants tolerant/resistant to this herbicide. The herbicide-tolerant plants as well as the sensitized plants were subjected to acetolactate synthase (ALS) enzyme assay to reveal the biochemical basis of plant tolerance. The results indicated that as the radiation dose increased, the tolerance to the herbicide application decreased in both lentil cultivars. Cultivar Jordan 1 showed sensitivity to chlorsulfuron herbicide at all treatments compared with that of Jordan 2. ALS enzyme activity in the two lentil cultivars was inhibited by chlorsulfuron. The irradiated plants (90 Gray) in both treated seeds plants (M1) and seeds of tolerant plants (M2) showed a lower level of inhibition to high concentration (250 μg/l) of chlorsulfuron herbicide. The results suggested an alteration of the expression system of ALS gene(s) leading to overproduction of altered ALS enzyme at the herbicide binding site of the enzyme in lentil plant.
The ability of sheep at different stocking rates to maintain the quality and quantity of their diet during the grazing season
Authors: GARCIA F. , CARRÈRE P. , SOUSSANA J. F. , BAUMONT R.
Published: May 2003

The degree to which grazers maintain the amount (organic matter intake) or the quality (organic matter digestibility) of their diet without adversely affecting the other component was addressed by investigating how sheep managed trade-offs between quantity and quality throughout the grazing season in an upland area of central France. Two groups of five dry ewes, grazing two plots of contrasting areas from April to the end of September 2000, were studied. On the smaller plot (1500 m2), the application of a high stocking rate (HSR) produced a resource of good quality but in low quantity; and on the larger plot (3000 m2), a low stocking rate (LSR) created a sward of low quality but in good quantity. In spring, in both conditions, the sheep maintained their intake of digestible organic matter (OM) at between 1000 and 1250 g/day. Both organic matter intake and digestibility remained high at both stocking rates. In summer, the intake of digestible OM decreased to between 750 and 1000 g/day. On HSR, this was mainly due to a decline of intake in relation to the decrease of intake rate and bite weight. On LSR a decrease in digestibility and to a lesser extent in intake was involved. At both stocking rates, the sheep maximized the digestibility of their diet by selecting the green laminae throughout the grazing season. In spring, the sheep modulated their daily grazing time to compensate the decrease in intake rate and maintained a high daily intake. In summer and autumn, the sheep failed to maintain their daily intake at the same level as previously observed. On both plots they modulated their daily grazing time to cover their needs (730 g/day), but they did not increase it further to maximize daily intake. This may be attributable to the costs involved in selecting (LSR) or taking (HSR) the best components from the sward.
Yield stability of cassava, maize, soya bean and cowpea intercrops
Authors: DAPAAH H. K. , ASAFU-AGYEI J. N. , ENNIN S. A. , YAMOAH C.
Published: May 2003

The yield stability of intercropping systems is important in developing cropping systems that produce economic yields over a wide range of environments. Field studies were conducted during the 1997/98 and 1998/99 growing seasons at three locations in the forest and forest–savannah transition zones of Ghana to determine yield, land use efficiency and yield stability of cassava (Manihot esculenta), maize (Zea mays), soya bean (Glycine max) and cowpea (Vigna unguiculata) intercrop systems. The cropping systems consisted of a factorial combination of two cassava varieties: ‘Gblemoduade’ (an improved, highly branched variety) and ‘Ankra’ (a local variety with fewer branches) and three spatial arrangements. Cowpea rows were planted in the minor season into cassava as a successive crop to maize and soya bean after their harvest in the major season. Intercropping significantly reduced grain or tuber yield of maize, cassava ‘Gblemoduade’ and cassava ‘Ankra’ by 23–70%, 16–49% and 24–64%, respectively. Maize yield decreased with increased number of soya bean rows. ‘Gblemoduade’ outyielded ‘Ankra’ by more than 100% under both intercrop and sole crop. The yield of soya bean increased with increased number of soya bean rows, but did not differ in response to the cassava variety. However, cowpea yield was higher when intercropped with ‘Ankra’ than with ‘Gblemoduade’. The intercrops had higher land use ratios (LER=1·27–2·83) and were more stable than the sole crops. Intercrops involving ‘Ankra’ had higher LER (2·14–2·18) than systems with ‘Gblemoduade’ (LER=1·83–1·99), but their yield stabilities were similar.
Urinary excretion and blood plasma allantoin in lambs and young goats starved and refed with a purine-free diet
Authors: FUJIHARA T. , SHEM M. N. , HIRANO T.
Published: May 2003

An experiment was carried out to determine endogenous excretion of allantoin (AN) in lambs and kids fasted and fed on a purine-free diet (milk replacer: MR). After weaning (40–50 days after birth), the animals were reared by feeding on MR until they were 120 days old. At 8 months of age, they were fasted for 8 days, and then re-fed on MR for 13 days. After weaning, AN excretion gradually decreased almost to a constant level at 80–120 days after birth (mean 0·14 mmol/kgW0·75/day). In goat kids, there was variation but no definite trend in urinary AN excretion in the period 40–120 days (mean 0·35 mmol/kgW0·75/day). Urinary AN excretion was very low after fasting for 8 days, mean values (per kgW0·75/day) being 0·13 mmoles for lambs and 0·17 mmoles for goat kids. In lambs, urinary AN excretion did not increase following subsequent re-feeding of MR, and for goat kids the increase was small. Changes in plasma AN concentration after fasting and re-feeding showed a similar response to that of urinary AN excretion for both sheep and goats so that there was a high positive correlation between the plasma AN and urinary AN excretion (r=0·881 for lambs and r=0·853 for kids). It is concluded that, in these young animals, urinary AN excretion rapidly responds to changes in plasma AN and is therefore likely to be a useful practical indication of endogenous PD excretion.
The potential of near-infrared reflectance spectroscopy to analyse soil chemical and physical characteristics
Authors: COZZOLINO D. , MORÓN A.
Published: May 2003

Near-infrared reflectance spectroscopy (NIRS) was used for the analysis of soil samples for silt, sand, clay, calcium (Ca), potassium (K), sodium (Na), magnesium (Mg), copper (Cu) and iron (Fe). A total of 332 samples of different soils from Uruguay (South America) were used. The samples were scanned in a NIRS 6500 (NIRSystems, Silver Spring, MD, USA) in reflectance. Cross validation was applied to avoid overfitting of the models. The coefficient of determination in calibration (R^2_{\rm cal}) and the standard errors in cross validation (SECV) were 0·80 (SECV: 6·8), 0·84 (SECV: 6·0), 0·90 (SECV: 3·6) in per cent for sand, silt and clay respectively. For both macro and microelements the R^2_{\rm cal} and SECV were 0·80 (SECV: 0·1), 0·95 (SECV: 2·9), 0·90 (SECV 0·8), for K, Ca, Mg in g/kg respectively, and 0·86 (SECV: 0·82) and 0·92 (SECV: 25·5) for Cu and Fe in mg/kg. It was concluded that NIRS has a great potential as an analytical method for soil routine analysis due to the speed and low cost of analysis.
Nitrogen value of poultry litter applications to root crops and following cereal crops
Authors: NICHOLSON F. A. , CHAMBERS B. J. , DAMPNEY P. M. R.
Published: May 2003

The efficiency of poultry litter nitrogen (N) utilization was studied in seven field experiments in eastern England during harvest years 1991 to 1994. Poultry litter was applied at different application rates in winter or spring, prior to sugar beet or potatoes. The mean manure N efficiency based on crop yields was 33% (range 25–43%) for sugar beet and 36% (range 13–66%) for potatoes. For potatoes, the manure N efficiency was greater from spring (mean 43%) than from winter application timings (mean 30%). The manure readily available N applied (i.e. ammonium-N+uric acid-N) and fertilizer N replacement values were well related (P<0·05) for both sugar beet and potatoes. Similarly, there was a good relationship (P<0·001) between the amounts of readily available N applied in the poultry litter dressings and measured elevations in spring soil mineral N supply. Where the poultry litter dressings supplied >600 kg/ha total N to sugar beet, root sugar concentrations were depressed (P<0·05) and amino-N concentrations increased (P<0·01). The soil mineral N supply following harvest of the sugar beet and potato crops was also increased where application rates supplied >600 kg/ha total N. Yield increases were also recorded in cereal crops grown the following season, but only where high rates of manure N (>600 kg/ha) had been applied. The current work has shown that the fertilizer N replacement value of poultry litter can be predicted based on the amounts of total and readily available N applied, providing guidance to farmers on appropriate reductions in inorganic fertilizer N applications to make allowance for poultry litter N supply.
The effect of rumen protozoa on the urinary excretion of purine derivatives in goats
Authors: FUJIHARA T. , TODOROKI M. , NAKAMURA K.
Published: May 2003

Urinary purine derivative (PD) excretion was estimated to examine the effect of rumen protozoa on total PD excretion in goats fed hay and a concentrate diet. The effect of increasing protozoa number in the rumen on nitrogen (N) balance and urinary PD excretion was determined after inoculation. Protozoa increased slowly until 4 days after inoculation, and on the 5th day after inoculation rapidly, finally (10 days) reaching 4·1×105/ml of rumen contents similar to that before defaunation. Urinary N excretion showed a small (non-significant) decrease. Urinary PD excretion did not change until the 7th day, and then the level decreased on the 8th day after faunation presumably due to the effect of increased protozoa in the rumen. The mean urinary total PD excretion significantly (P<0·05) decreased in the defaunated group compared with that in the faunated group. Comparable changes were not seen in plasma PD level of faunated and defaunated groups.
Effects of rate and timing of nitrogen fertilizer on disease control by fungicides in winter wheat. 1. Grain yield and foliar disease control
Authors: OLESEN J. E. , JØRGENSEN L. N. , PETERSEN J. , MORTENSEN J. V.
Published: May 2003

The effects of nitrogen (N) rate and timing on need for fungicide application in winter wheat (Triticum aestivum) were investigated in 3 years of field experiments on loamy sand soils in Denmark. A two-factor completely randomized experimental design was used, comprising seven combinations of different N fertilizer rates and application times, and five doses of fungicide (co-formulation propiconazole and fenpropimorph). Two different varieties of winter wheat with high susceptibility to powdery mildew (Blumeria graminis) were used, Florida in the first season and Pepital in the last two seasons. The severity of powdery mildew and septoria leaf spot (mainly Septoria tritici) varied between seasons from slight to moderate with powdery mildew dominating in the first season and septoria leaf spot in the last season. The severity of both powdery mildew and septoria leaf spot assessed as the Area Under the Disease Progress Curve (AUDPC) was increased by application of N in all years, and more so by early applied N. Grain yields increased with increasing N rate and fungicide dose. However, the observed grain yields did not reveal any N×fungicide interactions. Regression models were therefore fitted, relating grain yield to rate and timing of N fertilizer and to AUDPC of powdery mildew and septoria leaf spot, and relating AUDPC to rate and timing of N fertilizer and to fungicide dose. They demonstrated that septoria leaf spot had a considerably higher impact on grain yield than mildew. The optimal fungicide dose and N rate were defined as those giving the highest economic return. The regression models were used to estimate the effect of N rate and timing on optimal fungicide dose, and the effect of fungicide application on optimal N rate. The optimal fungicide dose increased almost linearly with N rate above a minimum N rate, but with a large dependency on price relations. Early applied N caused a higher demand for disease control. The fungicide applications in the model were mainly driven by the need to control septoria leaf spot, whereas powdery mildew gave a poor net return for control. The estimated optimal N fertilizer rate for untreated diseased crops was 60 kg N/ha lower than for crops without disease. The use of fungicides with an efficacy twice that of the EBI-fungicides used in this experiment would increase the optimal N rate by c. 20 kg N/ha.