Release of Short and Proline-Rich Antihypertensive Peptides from Casein Hydrolysate with an Aspergillus oryzae Protease

Angiotensin-I converting enzyme inhibitory activities were measured after hydrolysis of casein by 9 different commercially available proteolytic enzymes. Among these enzymes, a protease isolated from Aspergillus oryzae showed the highest angiotensin-I converting enzyme inhibitory activity per peptide. The A. oryzae peptide also showed the highest antihypertensive effect in spontaneously hypertensive rats when the systolic blood pressure was measured 5 h after oral administration of 32 mg/kg of various enzymatic hydrolysates. Significant antihypertensive effects were observed with dosages of 9.6, 32, and 96 mg of the A. oryzae peptide/kg of body weight (BW), and the effects were dependent on these peptide dosages. Analysis of peptide length showed the A. oryzae hydrolysate was the shortest of all tested casein hydrolysates; the peptide mixture had an average value of 1.4 amino acids (AA) in the sequence. To further characterize the A. oryzae hydrolysate, we analyzed the AA sequence of the whole peptide mixture. Various AA were detected at the first AA position, however, an increased number of Pro residues were observed at the second and third position of the A. oryzae hydrolysate. No strong signals were detected after the fourth AA position of the A. oryzae hydrolysate. These results suggest that the casein hydrolysate of A. oryzae, which expressed potent antihypertensive effects in spontaneously hypertensive rats, mainly contain short peptides of X-Pro and X-Pro-Pro sequences.

Are the results of surgical treatment of hepatocellular carcinoma poor if the tumor has spontaneously ruptured?

BACKGROUND

The aim of this study was to clarify whether the results of surgical treatment of ruptured hepatocellular carcinoma (HCC) are poorer than the results of surgical treatment of non-ruptured HCC.

METHODS

Out of a total of 224 HCC patients, the 6 patients with ruptured HCC were compared with 15 patients with non-ruptured HCC based on TNM stage IVA and having a Cancer of the Liver Italian Program (CLIP) score of 1 or 2.

RESULTS

There were no significant differences in clinical and pathological features between the two groups. The 1-year and 3-year overall survival rates were 69.3% and 21.2%, respectively, in the ruptured HCC group and 51.3% and 20.5%, respectively, in the non-ruptured HCC group. The 1-year and 3-year disease-free survival rates were 33.0% and 0%, respectively, in the ruptured HCC group and 38.9% and 15.6%, respectively, in the non-ruptured HCC group. The differences in survival rates between these two groups did not reach statistical significance.

CONCLUSION

Hepatic resection as definitive treatment after recovery from the initial insult of the rupture of HCC yields results similar to those obtained by surgical treatment of non-ruptured HCC at the same tumor stage and with the same degree of liver damage.

Z and W chromosomes of chickens: studies on their gene functions in sex determination and sex differentiation

Since the discovery of SRY/SRY as a testis-determining gene on the mammalian Y chromosome in 1990, extensive studies have been carried out on the immediate target of SRY/SRY and genes functioning in the course of testis development. Comparative studies in non-mammalian vertebrates including birds have failed to find a gene equivalent to SRY/SRY, whereas they have suggested that most of the downstream factors found in mammals including SOX9 are also involved in the process of gonadal differentiation. Although a gene whose function is to trigger the cascade of gene expression toward gonadal differentiation has not been identified yet on either W or Z chromosomes of birds, a few interesting genes have been found recently on the sex chromosomes of chickens and their possible roles in sex determination or sex differentiation are being investigated. It is the purpose of this review to summarize the present knowledge of these sex chromosome-linked genes in chickens and to give perspectives and point out questions concerning the mechanisms of avian sex determination.

Mycobacterial infection in natural killer T cell knockout mice

To gain a better understanding of the pathological role of natural killer (NK) T cells in murine tuberculosis, NKT knockout (KO) mice (J(alpha)281(-/-)mice) were utilized. Eight-week-old NKT KO mice of BALB/c origin and wild-type (WT) mice were infected with Mycobacterium tuberculosis Kurono strain by the airborne route using an airborne infection apparatus, and their capacity to control mycobacterial growth, granuloma formation, and cytokine production were examined. The NKT KO mice developed granulomatous lesions in the lungs; there was no statistically significant difference in pulmonary granuloma size between NKT KO and WT mice (p<0.01). The average CFU values increased 3 weeks post-infection, but decreased 9 and 11 weeks post-infection, in the lungs of NKT KO mice. When stimulated with Kurono strain in vitro, splenic cells from NKT KO mice produced less IFN-gamma than did those from WT mice. Expression of mRNA for IL-2, IL-4, IL-6, IL-10 and IL-12 p40 was slightly lower in NKT KO mice compared with WT mice. Our data indicate that NKT cells play a detrimental role in late-phase mycobacterial infection, although Th1 cells are essential in early-phase mycobacterial infection.

Relative importance of STAT4 in murine tuberculosis

This study was designed to determine the roles of STAT proteins in defence against mycobacterial infection. Airborne infection of STAT4 knockout (KO) mice with a Mycobacterium tuberculosis strain induced large granulomas with massive neutrophil infiltration over time, while that in STAT6 KO mice did not. The STAT4 KO mice succumbed to mycobacterial infection by the 80th day after infection. Compared with the levels in wild-type (WT) and STAT6 KO mice, pulmonary inducible nitric oxide synthase, interferon-alpha, -beta and -gamma mRNA levels were significantly lower in STAT4 KO mice, but expression of interleukin-2, -6, -12 and -18 mRNAs was slightly higher up to the fifth week after aerial infection. Therefore, STAT4, but not STAT6, appears to be a critical transcription factor in mycobacterial regulation.

Effect of different proton pump inhibitors, differences in CYP2C19 genotype and antibiotic resistance on the eradication rate of Helicobacter pylori infection by a 1-week regimen of proton pump inhibitor, amoxicillin and clarithromycin

AIM

To investigate the effect of different proton pump inhibitors, S-mephenytoin 4'-hydroxylase (CYP2C19) genotype and antibiotic susceptibility on the eradication rate of Helicobacter pylori.

METHODS

One hundred and eighty-seven H. pylori-infected peptic ulcer patients were randomly treated with either rabeprazole (10 mg b.d.) or lansoprazole (30 mg b.d.) plus amoxicillin (750 mg b.d.) and clarithromycin (400 mg b.d.) for 1 week. The antibiotic susceptibility and CYP2C19 genotype (extensive or poor metabolizer) were investigated.

RESULTS

The eradication rates in the rabeprazole-amoxicillin-clarithromycin (RAC) and lansoprazole-amoxicillin-clarithromycin (LAC) groups were 75% and 69%, respectively, on an intention-to-treat basis, and 80% and 75%, respectively, on a per protocol basis. The eradication rate for clarithromycin-resistant strains was significantly lower than that for clarithromycin-sensitive strains (24% vs. 86%, P < 0.05). For clarithromycin-sensitive strains in the LAC group, there was a tendency for a lower eradication rate in extensive than poor metabolizers. The eradication rate in extensive metabolizers in the RAC group tended to be higher than that in extensive metabolizers in the LAC group (89% vs. 78%, P = 0.079726).

CONCLUSIONS

The success of the 1-week proton pump inhibitor-amoxicillin-clarithromycin regimen depends on the susceptibility of H. pylori to clarithromycin. Moreover, differences in CYP2C19 genotype influence the eradication rates of lansoprazole-based therapy, and the rabeprazole-based regimen has an advantage especially in extensive metabolizers.

Efficient selection of genomic clones from a female chicken bacterial artificial chromosome library by four-dimensional polymerase chain reactions

A bacterial artificial chromosome (BAC) library consisting of 49,152 genomic clones was constructed from partially HindIII-digested female chicken embryo genomic DNA using the pBAC-Lac vector and maintained in 512 96-well plates. The mean insert size was approximately 150 kb, and the total library was estimated to contain about 3.2 times coverage of the diploid genome. In order to screen this library by the PCR, 296 BAC clone DNA samples were prepared: one sample each from 8 superpools (64 plates per superpool) and 36 samples of four-dimensionally (4-D) mixed clones from each superpool. A BAC clone of interest was selected by two-step PCR. First, 8 DNA samples representing superpools were subjected to PCR with a set of primers to amplify a part of the genomic sequence of interest. Second, 36 4-D DNA samples from the superpool that contained BAC clone(s) of interest were subjected to PCR with the same set of primers. The second step identified a plate and a well containing the BAC clone of interest. Selection of target BAC clone(s) from the whole library with the above procedure can be achieved within 1 to 4 d without using a radioactive probe. This procedure was applied successfully in the selection of BAC clones for Wpkci, chPKCI/HINT, ZOV3, and 17beta-HSD genes.

Role of interleukin (IL)-1 type 1 receptor in mycobacterial infection

It is important to gain a better understanding of IL-1-mediated signaling events in mycobacterial infection. In order to clarify the role of IL-1 receptor type 1 (IL-1 R1) in IL-1 R1, knockout (KO) mice were infected with either Mycobacterium tuberculosis H37Rv or Kurono strain by the respiratory route, and their ability to control mycobacterial growth, pulmonary granuloma formation, and cytokine mRNA expression was investigated. IL-1 R1 KO mice developed significantly larger (P< 0.01) granulomatous lesions with neutrophil infiltration in their lungs than wild-type mice did after infection with the M. tuberculosis Kurono strain. The number of mycobacterial colonies in lungs and spleen increased from five weeks post-infection. Interferon-y production by spleen cells was low in IL-1 R1 KO mice. It is concluded that the IL-1 R1 is essential for IL-1-mediated signaling events in mycobacterial infection.

Circadian rhythm of melatonin and prostaglandin in modulation of stress-induced gastric mucosal lesions in rats

BACKGROUND

We previously demonstrated the circadian variation of water-immersion restraint stress (WRS)-induced gastric mucosal lesions in rats.

AIM

To investigate the roles of melatonin and prostaglandin in the gastric mucosa in circadian modulation of WRS.

METHODS

Fasted rats were subjected to 4-h WRS during both the diurnal and nocturnal phases of a light/dark cycle. Mucosal lesions, serum melatonin concentrations, mucosal generation of prostaglandin E2 (PGE2) and mucosal gene expressions of cyclooxygenase (COX)-1 and -2 were evaluated.

RESULTS

Lesion area after 4-h stress during the dark phase was significantly smaller than that in light-phase controls. Serum melatonin concentration in control rats during the light phase was significantly increased 4 h after WRS, but PGE2 generation was decreased by 48% as compared to that in intact mucosa before stress. In the dark phase, melatonin concentration after 4-h WRS was significantly depressed as compared with the control level at the corresponding time. PGE2 concentrations after 4-h WRS in the dark phase were not decreased compared with the control level at the corresponding time, although PGE2 level was significantly lower than that in light-phase controls. Expression of COX-1 and COX-2 mRNA was detected after exposure to stress in both the light and dark phases.

CONCLUSION

These results suggest that circadian rhythm has an important role in the formation of stress-induced gastric mucosal lesions in rats. The circadian rhythm of melatonin responses and PGE2 generation may contribute to nocturnal/diurnal rhythmicity of gastric mucosal defences between day and night.

Wide distribution of Plasmodium ovale in Myanmar

The presence of Plasmodium ovale has never been previously reported in Myanmar. Using blood samples obtained in many villages across the country between 1996 and 2000, molecular diagnosis of Plasmodium species was made with semi- or full-nested polymerase chain reaction (PCR) with species-specific primers, followed by agarose gel electrophoresis to detect amplification products. The presence of P. ovale was also confirmed with the another PCR-based diagnosis, the microtiterplate hybridization (MPH) method using species-specific probes. Both methods target the A type of the small subunit ribosomal RNA gene of the four human malaria parasites. Plasmodium ovale DNA was amplified in samples from 65 (4.9%) of 1323 PCR-positive patients, with perfect agreement between results obtained by nested PCR and MPH. Only four P. ovale-infected patients had single-species infection; all others were coinfected with P. falciparum, P. vivax and/or P. malariae. Quadruple infections were observed in six subjects. Parasites with typical P. ovale morphology were found in only 19 patients by conventional microscopy of Giemsa-stained thin smears or fluorescence microscopy of acridine orange-stained thin smears. Plasmodium ovale infections were found in villages situated in the southern, central and western regions of Myanmar, suggesting that P. ovale may be widely distributed in this country.

Absence of Z-chromosome inactivation for five genes in male chickens

In order to examine if Z-chromosome inactivation, which is analogous to X-chromosome inactivation in mammals, takes place in male birds having ZZ sex chromosomes, five Z-linked genes of chickens which are expressed in both sexes in certain tissues were selected: i.e. genes for growth hormone receptor, nicotinic acetylcholine receptor beta3, aldolase B, beta1,4-galactosyltransferase I, and iron-responsive element-binding protein (also known as cytosolic aconitase). Antisense or sense riboprobe was prepared from an intronic sequence of each gene and subjected to fluorescence in situ hybridization to nascent transcripts of each gene in a nucleus. Each antisense riboprobe hyridized to two spots of nascent RNA which corresponded to its gene loci on the two Z chromosomes in a majority of nuclei in a tissue of the male. The efficiency of detection of two spots per nucleus was comparable to that for the glyceraldehyde-3-phosphate dehydrogenase gene, an autosomal housekeeping gene. These results suggest strongly that Z-chromosome inactivation, i.e. virtual silence of transcription at one of the alleles, does not take place for these five Z-linked genes in male chickens.

Chicken spindlin genes on W and Z chromosomes: transcriptional expression of both genes and dynamic behavior of spindlin in interphase and mitotic cells

Contigs of genomic clones covering about 480 kb on the terminal region of the short arm of chicken W chromosome were obtained. By applying the exon trapping procedure on this whole region, a chicken homolog of spindlin gene, chSpin-W, was identified and subcloned. A counterpart gene, chSpin-Z, was found near the centromere on the long arm of Z chromosome. Although protein-coding regions of both genes are nearly identical, a part of the 3'-untranslated region is sufficiently different to distinguish the transcript of chSpin-W. Both chSpin-W and chSpin-Z are transcribed in early embryos. chSpin-Z is transcribed in various tissues of adult chickens, while chSpin-W is transcribed most prominently in ovarian granulosa and thecal cells. When female chicken embryonic fibroblasts were transfected with a cDNA construct for red fluorescent protein or green fluorescent protein-fused spindlin or FLAG-tagged spindlin, the expressed spindlin was co-localized with SUMO-1 in nuclear dots, ND10, in interphase cells, while the expressed spindlin was localized on entire chromosomes during mitosis. The localization of spindlin in ND10 reappeared after mitosis in daughter cell nuclei. A C-terminal region of spindlin was suggested to be required for the localization of spindlin to ND10.

Extravasation on three-dimensional CT angiography in patients with acute subarachnoid hemorrhage and ruptured aneurysm

Three-dimensional computed tomographic angiography (CTA) is a noninvasive technique for detecting lesions after acute subarachnoid hemorrhage. We encountered extravasation on CTA, a finding that has not been reported previously. Three patients with saccular aneurysms showed extravasation on CTA performed within 3 h of the onset of hemorrhage, and all three patients died within 2 weeks. At autopsy, the site of rupture of the aneurysm was confirmed in all three cases. There were two patterns of extravasation shown by CTA, which seemed to depend on the direction of rupture. Extravasation on CTA might represent the natural progression of ruptured aneurysm and may indicate a poor prognosis.

Relative importance of NF-kappaB p50 in mycobacterial infection

To understand the role of NF-kappaB in the development of murine tuberculosis in vivo, NF-kappaB p50 knockout mice were infected with Mycobacterium tuberculosis by placing them in the exposure chamber of an airborne-infection apparatus. These mice developed multifocal necrotic pulmonary lesions or lobar pneumonia. Compared with the levels in wild-type mice, pulmonary inducible nitric oxide synthase, interleukin-2 (IL-2), gamma interferon, and tumor necrosis factor alpha mRNA levels were significantly low but expression of IL-10 and transforming growth factor beta mRNAs were within the normal ranges. The pulmonary IL-6 mRNA expression level was higher. Therefore, NF-kappaB and its interaction with host cells play an important role in the pathogenesis of tuberculosis.

Perfusion of medium improves growth of human oral neomucosal tissue constructs

Tissue engineering of the oral mucosa may be useful in congenital cleft palate repairs, defects following extirpative oncologic surgery, and periodontal disease. One of the limitations of in vitro growth of oral mucosal constructs is central necrosis of 3-dimensional tissues. We tested the hypothesis that medium perfusion would enhance oral mucosal histogenesis in vitro. Normal human oral keratinocytes were obtained from young to middle-aged adults. Porous 3-dimensional matrices were prepared from collagen and chondroitin sulfate with some crosslinked with glutaraldehyde. Each device was seeded with 5.0 x 10(5) human oral keratinocytes. The seeded matrices were cultured with or without perfusion of medium at 1.3 ml/min. Histologic analysis of samples cultured for 3, 7, or 14 days showed superior viability and proliferation when perfused. At day 7, the average number of cell layers of the neoepithelium of sponges in the perfused culture system (9.4 +/- 1.0) was 88% greater than for the nonperfused culture system (5.0 +/- 0.9, p<0.005). Glutaraldehyde crosslinking did not influence cellular proliferation or the extent of matrix's shrinkage in either culture system. This study shows that medium perfusion enhanced cell viability and proliferation of human oral keratinocytes cultured in porous 3-dimensional matrices.

Theoretical analysis of mixed irradiation (3)

As the model we proposed last year was contradictory to experimental data, we revised again the models for mixed irradiation by Zaider and Rossi and by Suzuki, substituting a 'reciprocal-time' pattern of repair function for a first-order one in reduction and interaction factors of the models, although we used a second order repair function last year. The reduction factor, which reduces the contribution of the square of a dose to cell killing in the models, and the interaction factor, which also reduces the contribution of the interaction of two or more doses of different types of radiation, were formulated by using the 'reciprocal-time' pattern of repair function. These newly modified models for mixed irradiation could express or predict cell survival more accurately than the older ones, especially when irradiation is prolonged at low dose rates. We present survival curves of cells calculated from the newly and the older models of assumptive simultaneous mixed irradiation with two or three types of radiation.

Asymptomatic pyuria in diabetic women

The aim of the present study was to determine the prevalence of and the host factors for asymptomatic pyuria (ASP) in women with type 2 diabetes. The study included 179 type 2 diabetic women and consecutive 455 non-diabetic women attending as out-patients in 1996. Patients with symptoms of a urinary tract infection were excluded. ASP was defined as the presence of more than 10 leukocytes/high-power field in a random urine sample. Diabetic women more often had ASP than non-diabetic women (27.9 vs. 15.8%, P<0.001). The prevalence of ASP was significantly increased in patients with a duration of diabetes exceeding 15 years (0 approximately 4 years; 20.3%, 5 approximately 9 years; 24.3%, 10 approximately 14 years; 23.8%, and > or =15 years; 46.3%). No differences were evident in HbA(1C) between diabetic patients without ASP and those with ASP. Diabetic women with ASP more often had diabetic retinopathy, neuropathy, nephropathy, cerebrovascular disease, ischemic heart disease, and hyperlipidemia than those without ASP. However, no statistically significant differences were evident in the prevalence of hypertension, constipation, or dementia. As the degree of neuropathy increases, it is accompanied by an increasing prevalence of ASP (none, 21.4%; blunt tendon reflexes, 24.5%; symptomatic, 50.0%; and gangrene, 66.6%). The prevalence of ASP was significantly increased in the patients with proliferative diabetic retinopathy (none, 23.2%; background, 29.4%; pre-proliferative, 18.2%; and proliferative, 50.0%). As the degree of nephropathy increases, it is accompanied by an increasing prevalence of ASP (none, 20.0%; microalbuminuria, 31.9%; macroalbuminuria, 37.0%; and renal failure, 60.0%). Thus, the prevalence of ASP is increased in women with diabetes and increased with longer duration of diabetes but was not affected by glucose control. The incidence of ASP increases significantly as diabetic microangiopathy becomes severer.

Simple and low-cost tele-nuclear medicine conference system with the e-mail protocol

PURPOSE

Because of the recent innovative growth in computer technology, digital imaging, and the Internet, we can take advantage of these facilities for education and clinical work in nuclear medicine. We developed a tele-nuclear medicine conference system with electronic mail (e-mail) on the Internet.

METHODS

Twenty-one physicians (20 radiologists, 1 neurologist), 6 technologists and 2 medical students in six university hospitals (Japan 5, Canada 1), 5 local hospitals in Japan participated in this project. We used digital still cameras (330 k pixels) equipped with a floppy disk drive and 10 x optical zoom to digitize images with JPEG compression (640 x 480 matrix). The images were attached to e-mail messages (containing a brief description of each case). The mail was sent simultaneously to all members on the mailing list. Scintigram and SPECT images as well as other radiological images were sent by e-mail. Reply mails about each case were sent to all members via the mailing list.

RESULTS

During a period of 6 months, 18 cases (tumor/infection: 7, bone: 6, cardiovascular: 1, neurology; 3, endocrine: 1) with 144 e-mails (average 5.6/case) were submitted to the conference. The average period of discussion was 15.6 days. The number of attached images was 1 to 9 (average, 4.2/e-mails). JPEG compression rate was 1/10 to 1/20. The quality of the images was good enough for discussion. Some cases required additional images for further discussion.

CONCLUSION

Our tele-nuclear medicine conference with an electronic mailing list and digital camera was simple and low-cost. The conference system was useful for education and clinical work.

The N-terminal internal region of BLM is required for the formation of dots/rod-like structures which are associated with SUMO-1

Bloom Syndrome (BS) is a human autosomal genetic disorder characterized by a predisposition to a variety of malignant tumors. The gene responsible for BS encodes a protein (BLM) consisting of 1417 amino acids with a nuclear localization signal in the C-terminal region, which is a member of the RecQ helicase family. We previously showed, using a yeast two-hybrid system, that BLM interacted with Ubc9, which is the conjugating enzyme of SUMO-1 (small ubiquitin-related modifier-1). In the present study, we exogenously expressed a green fluorescent protein-tagged Bloom syndrome protein, GFP-BLM, in human 293EBNA cells and found that it formed dots/rod-like structures associated with SUMO-1 in the nucleus. Deletion experiments indicated that the region from amino acids 238 to 586 of BLM is required for the formation of dots/rod-like structures associated with SUMO-1, and the DNA helicase domain, but not the helicase activity itself, slightly affected the formation and/or stability of these structures. Expression of a GFP-BLM which contained the 238-586 region, but lacked the C-terminal nuclear localization signal, resulted in localization to the cytoplasm without the formation of dots/rod-like structures and association with SUMO-1, indicating that these events occur only in the nucleus.

Transcripts of the MHM region on the chicken Z chromosome accumulate as non-coding RNA in the nucleus of female cells adjacent to the DMRT1 locus

The male hypermethylated (MHM) region, located near the middle of the short arm of the Z chromosome of chickens, consists of approximately 210 tandem repeats of a BamHI 2.2-kb sequence unit. Cytosines of the CpG dinucleotides of this region are extensively methylated on the two Z chromosomes in the male but much less methylated on the single Z chromosome in the female. The state of methylation of the MHM region is established after fertilization by about the 1-day embryonic stage. The MHM region is transcribed only in the female from the particular strand into heterogeneous, high molecular-mass, non-coding RNA, which is accumulated at the site of transcription, adjacent to the DMRT1 locus, in the nucleus. The transcriptional silence of the MHM region in the male is most likely caused by the CpG methylation, since treatment of the male embryonic fibroblasts with 5-azacytidine results in hypo-methylation and active transcription of this region. In ZZW triploid chickens, MHM regions are hypomethylated and transcribed on the two Z chromosomes, whereas MHM regions are hypermethylated and transcriptionally inactive on the three Z chromosomes in ZZZ triploid chickens, suggesting a possible role of the W chromosome on the state of the MHM region.

A novel SOD1 gene mutation in familial ALS with low penetrance in females

We identified a novel missense mutation in the Cu/Zn superoxide dismutase gene in a family with amyotrophic lateral sclerosis (ALS). The mutation was a transition of T to C, resulting in a substitution of leucine 126 to serine in exon 5. The family had very unique clinical features of extremely mild severity only in the legs of two male patients with onset of 42 and 52 years old, and their mothers did not develop any symptom even after reaching the age of 80 and carrying the same mutation. The present study suggests that there are other factors that delay or prevent the disease.

Novel actin-related proteins in vertebrates: similarities of structure and expression pattern to Arp6 localized on Drosophila heterochromatin

Actin-related proteins (Arps), which share a basal structure with actin isoforms but possess different functions, have been identified in a wide variety of organisms. The Arps are classified into subfamilies based on the relatedness of their sequences and functions. Recently, several Arp subfamilies have been shown to be localized in the nucleus and included in protein complexes involved in the organization of chromatin structure, for example, in chromatin remodeling and histone acetyltransferase complexes. A member of the Arp6 subfamily in Drosophila, dArp6, is localized on centric heterochromatin together with heterochromatin protein 1 (HP1). We have identified the first examples of the Arp6 subfamily in vertebrates, novel human and chicken Arps, hArp6 and gArp6, respectively. They are closely related to each other (98% similar) and show apparent similarity to dArp6 (70%). In addition, the hArp6 gene possesses evolutionarily conserved exon/intron structures compared with genes for members of the Arp6 subfamily in invertebrates. Like Drosophila dArp6, gArp6 is expressed abundantly in the early developmental stages, when heterochromatin condensation and nuclear maturation occur. The finding of a conserved Arp6 subfamily in vertebrates will contribute to the understanding of molecular mechanisms of heterochromatin organization.

Identification of the sex of a wide range of Carinatae birds by PCR using primer sets selected from chicken EE0.6 and its related sequences

A 0.6 kb EcoRI fragment (EE0.6), cloned from the W chromosome of chickens, is a nonrepetitive sequence and contains an exonlike sequence, ET15, which is likely a part of a pseudogene. The EE0.6 sequence is conserved in all species of birds examined both in Carinatae and Ratitae. A counterpart sequence of EE0.6 is present on the Z chromosome. The extent of diversity between the W- and Z-linked sequences are variable among species. The W- and Z-linked EE0.6 sequences, cloned from 12 different species, were compared and four forward and three reverse primers were selected to amplify parts of the EE0.6 sequence by polymerase chain reaction (PCR). By choosing a suitable combination of primers for EE0.6 and a set of primers for a Z/W-common sequence, as an internal control, the sex of 36 species belonging to 16 different orders of Carinatae could be determined clearly by PCR. The sex of two other species representing different orders could be determined by Southern blot hybridization using ET15 as a probe. For the two Ratitae species, emu and ostrich, EE0.6 sequences on W and Z chromosomes could not be distinguished either by PCR or Southern blotting.