The C-Terminal Fragment of Prostate-Specific Antigen,a 2331 Da Peptide,as a New Urinary Pathognomonic Biomarker Candidate for Diagnosing Prostate Cancer

Background and Objectives

Prostate cancer (PCa) is one of the most common cancers and leading cause of cancer-related deaths in men. Mass screening has been carried out since the 1990s using prostate-specific antigen (PSA) levels in the serum as a PCa biomarker. However, although PSA is an excellent organ-specific marker, it is not a cancer-specific marker. Therefore, the aim of this study was to discover new biomarkers for the diagnosis of PCa.

Materials and Methods

We focused on urine samples voided following prostate massage (digital rectal examination [DRE]) and conducted a peptidomic analysis of these samples using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MSⁿ). Urinary biomaterials were concentrated and desalted using CM-Sepharose prior to the following analyses being performed by MALDI-TOF/MSⁿ: 1) differential analyses of mass spectra; 2) determination of amino acid sequences; and 3) quantitative analyses using a stable isotope-labeled internal standard.

Results

Multivariate analysis of the MALDI-TOF/MS mass spectra of urinary extracts revealed a 2331 Da peptide in urine samples following DRE. This peptide was identified as a C-terminal PSA fragment composed of 19 amino acid residues. Moreover, quantitative analysis of the relationship between isotope-labeled synthetic and intact peptides using MALDI-TOF/MS revealed that this peptide may be a new pathognomonic biomarker candidate that can differentiate PCa patients from non-cancer subjects.

Conclusion

The results of the present study indicate that the 2331 Da peptide fragment of PSA may become a new pathognomonic biomarker for the diagnosis of PCa. A further large-scale investigation is currently underway to assess the possibility of using this peptide in the early detection of PCa.     

Structure of the Bombyx mori fibroin light-chain-encoding gene: upstream sequence elements common to the light and heavy chain.

Two overlapping genomic clones containing the fibroin light-chain (Fib-L)-encoding gene (Fib-L) were obtained from the cosmid library of the silkworm, Bombyx mori J-139, by hybridization with the Fib-L cDNA clone. Sequencing of the 14.6-kb region revealed that Fib-L was 13472 bp long containing seven exons, and that the gene contained a large first intron which occupied about 60% of the gene. Comparison of restriction patterns of the J-139 Fib-L with those of eight other B. mori breeds producing normal-level fibroin demonstrated that considerable restriction-fragment length polymorphisms were present in regions containing the first intron and the 3′-flanking sequence. However, sizes of the Fib-L mRNA and the Fib-L polypeptide were very similar among the nine breeds tested, suggesting that the exon sequences and the splice signals were all well conserved. 5′-Flanking regions of Fib-L and the fibroin heavy-chain (Fib-H)-encoding gene (Fib-H) compared in this study contained three 18-30-bp sequences of high similarity and many 8-10-bp common elements, six of which coincided with the binding sites of homeodomain proteins. Gel retardation assays with the nuclear extracts of the posterior and middle silk glands suggested that protein factors present in the posterior silk-gland nuclei could bind to a set of those common upstream elements.     

从营养扰动实验看原绿球藻在近海分布的制约因素

地球上细胞最小、丰度最大的放氧光合自养原核生物原绿球藻 (Prochlorococcus)发现于热带大洋 ,并被证实可在某些近海甚至近岸水域大量分布。但除温度之外 ,原绿球藻自然分布的控制因子尚不明了。从近海和大洋生态条件的主要差别考虑 ,在南海进行了主要营养盐———氮、磷和微量元素———铁、钴扰动的现场培养实验 ,并应用流式细胞技术监测原绿球藻及聚球藻 (Synechococcus)、超微型真核浮游植物 (pico_eukaryotes)的细胞丰度和单细胞色素含量的响应以及细菌的影响。结果表明 ,磷和钴的添加有利于原绿球藻 ,而氮和铁的添加更有利于聚球藻和超微型真核浮游植物。同时 ,由环境条件引起的生物响应又间接地导致超微型生物之间的相互作用。因而 ,原绿球藻在近海的分布 ,可能受到营养盐组成等环境因子以及生物之间的相互作用等多方面的限制和影响     

Alleviation of Aluminum Stress and Stimulation of Tea Pollen Tube Growth by Fluorine

Aluminum (Al) and fluorine (F) were found to affect tea pollentube growth on an agar medium. Not only was the growth stronglyrepressed by increasing Al content of the medium but it wasalso distinctly affected by declining pH from 5.2 to 4.4. Additionof 0.2 mM Al as Al₂(SO₄)₃ to a pH 4.6 medium containing 1.2%agar, 8% sucrose and 17 ppm boron remarkably repressed tea pollentube growth. However, NaF added to medium containing Al clearlyalleviated the growth inhibition. This effect was observed with0.2 mM and 0.4 HIM NaF, and the presence of 0.6 mM and 1.2 DIMNaF with 0.2 mM Al even produced a stimulatory effect. Treatmentwith NaF alone significantly stimulated growth at pH 4.6 and5.2. These results indicate that Al-F complexes have a favorablerather than adverse effect on tea pollen tube growth. (Received November 22, 1982; Accepted April 20, 1983)     

Pollination biology of the endangered orchid Cypripedium japonicum in a fragmented forest of Japan

Pollination biology studies of the endangered orchid Cypripedium japonicum were conducted in its natural habitat using pollinator observation and hand‐pollination experiments. The observed fruit set was as follows: artificial outcross‐pollinated, 100%; artificial self‐pollinated, 100%; pollinator‐excluded, 0%; and emasculated flowers, 0%. These results show that this species, although self‐compatible, is neither autogamous nor agamospermous. The fruit set for open‐pollinated flowers was 14.9%, which suggests that the study population was subject to pollinator limitation. The nectarless flowers of C. japonicum were exclusively visited and pollinated by the queens of two bumblebee species (Bombus ardens and B. diversus diversus). It is probable that the nectarless flowers of C. japonicum attract pollinators through a generalized food deceptive system.     

A Bacillus subtilis gene-encoding protein homologous to eukaryotic SMC motor protein is necessary for chromosome partition

We have analysed the function of a gene of Bacillus subtilis , the product of which shows significant homology with eukaryotic SMC proteins essential for chromosome condensation and segregation. Two mutant strains were constructed; in one, the expression was under the control of the inducible spac promoter (conditional null) and, in the other, the gene was disrupted by insertion (disrupted null). Both could form colonies at 23°C but not at 37°C in the absence of the expression of the Smc protein, indicating that the B. subtilis smc gene was essential for cell growth at higher temperatures. Microscopic examination revealed the formation of anucleate and elongated cells and diffusion of nucleoids within the elongated cells in the disrupted null mutant grown at 23°C and in the conditional null mutant grown in low concentrations of IPTG at 37°C. In addition, immunofluorescence microscopy showed that subcellular localization of the Spo0J partition protein was irregular in the smc disrupted null mutant, compared with bipolar localization in wild-type cells. These results indicate that the B. subtilis smc gene is essential for chromosome partition. The role of B. subtilis Smc protein in chromosome partition is discussed.     

Dual intracellular signaling by proteolytic cleavage of membrane-anchored heparin-binding EGF-like growth factor

Heparin-binding EGF-like growth factor (HB-EGF), a member of the EGF family, is synthesized as a membrane-anchored precursor (proHB-EGF) that is cleaved to release a soluble HB-EGF by specific metalloproteases. Proteolytic cleavage of proHB-EGF yields amino- and carboxy-terminal fragments (HB-EGF and HB-EGF-C). Recent studies indicate that the processing of proHB-EGF is strictly regulated and involved in a variety of biological processes and that not only HB-EGF but also HB-EGF-C functions as a signaling molecule. ProHB-EGF generates dual intracellular signaling molecules by its proteolytic cleavage.