Tracheostoma Closure Technique Using Three Local Flaps

When a tracheostoma is no longer needed, the opening normally closes spontaneously after cannula removal, but some cases require tracheostoma closure. This procedure has been well described, but must be performed in such a way as to minimize its invasiveness and complications while securing a high closure rate. Our procedure for conducting tracheostoma closure technique involves the creation of two hinge flaps and one cover flap to close the tracheostomy opening. We reviewed the medical records of 23 patients (12 men, 11 women; mean age 60.0 SD19.7 years) who underwent tracheostoma closure technique between 2001 and 2019. Surgery was indicated for patients in whom closure had not occurred after conservative monitoring for ≥ 2 months following cannula removal. The surgical procedure began by raising two hinge flaps on either side of the tracheostomy opening, turning the skin surface to the luminal side to form the anterior tracheal wall. Rather than a single layer of skin, multiple skin layers were sutured together to prevent air leakage from between hinge flaps. A further cover flap was produced to cover the anterior tracheal wall, closing the tracheostomy opening. Postoperatively, the tracheal lumen was observed via fiberscopy. No stenosis of the tracheal lumen occurred in any patients, and the tracheocutaneous fistula was successfully closed in all cases. Tracheostoma closure technique using hinge flaps to reconstruct the anterior tracheal wall and a cover flap as a skin flap to cover the skin defect appears useful for patients with failure of spontaneous tracheocutaneous fistula closure.

Repeated Surgery in a Case of Epithelial-Myoepithelial Carcinoma of the Parotid Gland that was Difficult to Distinguish from Pleomorphic Adenoma

Epithelial-myoepithelial carcinoma (EMC) of the parotid gland is a comparatively rare tumor that accounts for less than 1% of all salivary gland tumors. A patient with EMC of the parotid gland that was initially diagnosed as pleomorphic adenoma and that recurred locally during the watchful waiting period but was controlled by surgery under local anesthesia is reported. An 80-year-old man had noticed a swelling in the left infra aural region. A left parotid gland tumor was suspected, and he was referred to our department. Magnetic resonance imaging (MRI) and fine-needle aspiration cytology findings were suggestive of pleomorphic adenoma of the superficial lobe of the parotid gland, and this was therefore resected under general anesthesia. Postoperative histopathological examination, immunostaining, and genetic tests resulted in a diagnosis of EMC. Postoperative pathological review showed that part of the resection margin was positive. The possibility of recurrence was explained to the patient, and additional treatment was recommended, but since the patient did not desire this, a policy of watchful waiting was adopted. Signs of cutaneous metastasis in the left infra aural region were detected at 13 months postoperatively, and this metastasis was excised under local anesthesia. The resection margin was negative, and the patient's course remains uneventful. EMC is classified as a low-grade malignant tumor, but it requires stringent monitoring because of its frequent local recurrence. Since local control can usually be achieved by surgical treatment alone, and postoperative adjuvant therapy may not necessarily warranted.

A Printed Flexible Humidity Sensor with High Sensitivity and Fast Response Using a Cellulose Nanofiber/Carbon Black Composite

In the emerging Internet of Things (IoT) society, there is a significant need for low-cost, high-performance flexible humidity sensors in wearable devices. However, commercially available humidity sensors lack flexibility or require expensive and complex fabrication methods, limiting their application and widespread use. We report a high-performance printed flexible humidity sensor using a cellulose nanofiber/carbon black (CNF/CB) composite. The cellulose nanofiber enables excellent dispersion of carbon black, which facilitates the ink preparation and printing process. At the same time, its hydrophilic and porous nature provides high sensitivity and fast response to humidity. Significant resistance changes of 120% were observed in the sensor at humidity ranging from 30% RH to 90% RH, with a fast response time of 10 s and a recovery time of 6 s. Furthermore, the developed sensor also exhibited high-performance uniformity, response stability, and flexibility. A simple humidity detection device was fabricated and successfully applied to monitor human respiration and noncontact fingertip moisture as a proof-of-concept.

Effect of a Single Injection of Basic Fibroblast Growth Factor into the Vocal Folds: A 36-Month Clinical Study

OBJECTIVE

A single injection of basic fibroblast growth factor (bFGF) into the vocal folds of patients with glottal insufficiency has been shown to be effective for a few years. However, the long-term therapeutic effect of a single injection of bFGF into the vocal folds has yet to be demonstrated. In this study, the therapeutic effect of a single injection of bFGF into the vocal folds was investigated over several years by monitoring patients for 36 months following this treatment.

METHODS

Nineteen patients with glottal insufficiency received injections of bFGF diluted to 20 μg/mL in the superficial layer of the lamina propria of the bilateral vocal folds. The following parameters were evaluated at preinjection baseline and 6, 12, 18, 24, and 36 months later, and statistical comparisons were performed. The parameters evaluated were: the Grade, Rough, Breathy, Asthenic, and Strained (GRBAS) scale score; maximum phonation time; acoustic analysis; and glottal wave analysis (GWA) and kymograph edge analysis (KEA) using high-speed digital imaging (HSDI). The amplitude perturbation quotient (APQ) and period perturbation quotient (PPQ) were measured by acoustic analysis. The mean minimum glottal area during vocalization and mean minimum distance between the vocal folds were measured by GWA. The amplitudes of the bilateral vocal folds were measured by KEA.

RESULTS

Postinjection, the GRBAS scale score decreased from 6 months after injection, and maximum phonation time was prolonged. The mean minimum glottal area during vocalization and the mean minimum distance between the vocal folds calculated by GWA of HSDI decreased significantly after 6 months. These effects persisted until 36 months postinjection. APQ and PPQ derived from acoustic analysis tended to decrease, but not significantly. There was no clear change in the amplitudes of the bilateral vocal folds calculated by KEA of HSDI before and after injection.

CONCLUSIONS

These results suggest that the effects of a single injection of bFGF into the vocal folds persist for 36 months.

Printed Soft Sensor with Passivation Layers for the Detection of Object Slippage by a Robotic Gripper

Tactile sensing, particularly the detection of object slippage, is required for skillful object handling by robotic grippers. The real-time measurement and identification of the dynamic shear forces that result from slippage events are crucial for slip detection and effective object interaction. In this study, a ferroelectric polymer-based printed soft sensor for object slippage detection was developed and fabricated by screen printing. The proposed sensor demonstrated a sensitivity of 8.2 μC·cm-2 and was responsive to shear forces applied in both the parallel and perpendicular directions. An amplifier circuit, based on a printed organic thin-film transistor, was applied and achieved a high sensitivity of 0.1 cm2/V·s. Therefore, this study experimentally demonstrates the effectiveness of the proposed printable high-sensitivity tactile sensor, which could serve as part of a wearable robotic e-skin. The sensor could facilitate the production of a system to detect and prevent the slippage of objects from robotic grippers.

Ultralow mode-volume photonic crystal nanobeam cavities for high-efficiency coupling to individual carbon nanotube emitters

The unique emission properties of single-walled carbon nanotubes are attractive for achieving increased functionality in integrated photonics. In addition to being room-temperature telecom-band emitters that can be directly grown on silicon, they are ideal for coupling to nanoscale photonic structures. Here we report on high-efficiency coupling of individual air-suspended carbon nanotubes to silicon photonic crystal nanobeam cavities. Photoluminescence images of dielectric- and air-mode cavities reflect their distinctly different mode profiles and show that fields in the air are important for coupling. We find that the air-mode cavities couple more efficiently, and estimated spontaneous emission coupling factors reach a value as high as 0.85. Our results demonstrate advantages of ultralow mode-volumes in air-mode cavities for coupling to low-dimensional nanoscale emitters.

Short communication: Development of the first follicular wave dominant follicle on the ovary ipsilateral to the corpus luteum is associated with decreased conception rate in dairy cattle

In this study, we examined the effect of the locations of the first-wave dominant follicle (DF) and corpus luteum (CL) on fertility. In total, 350 artificial insemination (AI) procedures were conducted (lactating dairy cows: n=238, dairy heifers: n=112). Ovulation was confirmed 24 h after AI. The locations of the first-wave DF and CL were examined 5 to 9d after AI using rectal palpation or transrectal ultrasonography. Lactating dairy cows and dairy heifers were divided into 2 groups: (1) the ipsilateral group (IG), in which the DF was ipsilateral to the CL; and (2) the contralateral group (CG), in which the DF was contralateral to the CL. Pregnancy was diagnosed using transrectal ultrasonography 40d after AI. Conception rates were 54.0% in all cattle: 48.9% in lactating dairy cows, and 58.9% in dairy heifers. The incidence of the first-wave DF location did not differ between IG and CG (all cattle: 184 vs. 166; lactating cows: 129 vs. 109; heifers: 55 vs. 57 for IG vs. CG). Conception rates were lower in IG than in CG (all cattle: 40.2 vs. 69.3%; lactating dairy cows: 38.0 vs. 67.0%; dairy heifers: 45.5 vs. 73.7%, for IG vs. CG). Conception rate was not affected by season or live weight in heifers and lactating cows. In addition, days in milk at AI, milk production, body condition score, and parity did not affect conception in lactating cows. In summary, development of the first-wave DF in the ovary ipsilateral to the CL was associated with reduced conception rates in both lactating cows and heifers.

116 THE CHARACTERISTICS OF CORPUS LUTEUM SIZE, BLOOD FLOW, AND PLASMA PROGESTERONE CONCENTRATION AFTER OVULATION OF THE FIRST AND SECOND WAVE DOMINANT FOLLICLE

The characteristics of the corpus luteum (CL) are greatly affected by the characteristics of the preceeding preovulatory follicle, such as follicle size and function. A previous study reported that the concentration of oestradiol in follicular fluid and production of androstenedione and progesterone (P4) by cultured theca cells are higher in the first follicular wave dominant follicle than in the second follicular wave dominant follicle. In addition, blood flow in the wall of the preovulatory follicle is higher in the first follicular wave than in the second follicular wave. These results suggest that the characteristics of the dominant follicle in the first and the second follicular wave may be different. The objective of this study was to compare CL characteristics, such as diameter, cross-sectional area, blood flow area, and plasma P4 concentration after ovulation of the dominant follicle between the first and the second follicular waves. Preovulatory follicles and CL formed after ovulation of the first follicular wave (W1; n = 5) and second follicular wave (W2; n = 6) were examined in non-lactating Holstein cows. In W1, PGF2α and GnRH were administrated on D7 and D9 of the oestrus cycle (D0 = oestrus), respectively, to induce follicular maturation. In W2, GnRH was administrated on D6 to induce a new follicular wave; subsequently, PGF2α and GnRH were administrated on D14 and D16, respectively. Diameter and percentage of follicular circumference with blood flow of preovulatory follicle on D10 in W1 and D17 in W2 were measured by transrectal colour Doppler ultrasonography. Diameter, cross-sectional area, and blood flow area of CL formed after ovulation in W1 (W1CL) and W2 (W2CL) were also examined on Day 3, 6, and 9 after ovulation (Day 1 = ovulation day). Blood samples were collected from Day 1 to 9 for P4 measurement. Quantitative end-points for diameter and percentage of follicular circumference with blood flow of the preovulatory follicle were analysed between the groups by using the unpaired Student's t-test. Diameter, cross-sectional area, blood flow area of CL, and plasma P4 concentration were analysed by repeated-measures ANOVA followed by Scheffe's F-test as a multiple comparison test. Larger diameter and higher percentage of follicular circumference with blood flow of the preovulatory follicle were observed in W1 compared with those in W2 (P < 0.01). Diameter of CL was larger in W1CL than in W2CL regardless of day (P < 0.001). Cross-sectional area of CL was larger in W1CL than in W2CL on Day 6 and 9 but not on Day 3. Blood flow area of CL was larger in W1CL than in W2CL on Day 3 and 6 but not in Day 9. Plasma P4 concentrations were higher in W1CL than in W2CL on Day5 and 7 (P < 0.05). In conclusion, larger size and higher percentage of follicular circumference with blood flow of preovulatory follicle in W1 lead to a larger size and a blood flow area of CL as well as higher plasma P4 concentration. These results suggest that preovulatory blood flow status affects the morphology and function of CL.

Genetic control of weediness traits and the maintenance of sympatric crop-weed polymorphism in pearl millet (Pennisetum glaucum)

Pearl millet (Pennisetum glaucum), a diploid outcrossing crop widely grown in semiarid tropics, provides a unique extant material for the study of crop-weed interactive evolution. Co-occurrence of a weedy, shattering type of pearl millet with the cultivated one is the rule in the traditional agro-ecosystem in the Sahel zone of Africa. Selfed progeny of weed-type plants invariably segregated into distinct weed and crop types in an approximately 3:1 ratio. Genetic analysis using a cleaved amplified polymorphic sequence (CAPS) marker strongly suggested that a series of differences between the crop and the weed types are determined by a single putative supergene that has two allelic types, C and W. The crop-type plants are CC homozygotes, and the weed-type plants are CW heterozygotes. WW homozygotes are sterile and rare in the field. Thus, the CW weed plants recurrently arise from crosses between the crop and the weed, as well as from crosses among the weed-type plants. The weed type appears to have a sufficiently high fitness to maintain the W allele in the pearl millet population, resulting in the perpetuation of this unique crop-weed polymorphism.

Expression and purification of recombinant swine interleukin-4

The swine interleukin-4 (SwIL-4) cDNA was cloned by RT-PCR. It was expressed using an expression vector pQE30 in E. coli, a baculovirus AcNPV vector pVL1392 in insect cells, and a pCAGGS vector in mammalian cells. The rSwIL-4 proteins expressed from bacteria and insect cells were purified using a chelating affinity column and a mAb-coupled immunoaffinity column. The amount of the products and their bioactivities were compared. All recombinant cytokines were efficiently reacted with the specific antibodies and the molecular weight of rSwIL-4 was approximately 16 kDa in E. coli, 15 and 18 kDa in insect cells, and 15 and 20 kDa in mammalian cells. Variations of molecular weight observed in insect and mammalian cells were probably due to different modification ways of glycosylation. All these recombinant proteins retained their antigenicity and were biologically active in inducing human TF-1 cell proliferation in vitro. The simple purification method will make it possible to evaluate the in vitro and in vivo effects of IL-4 in pigs.

Expression and characterization of the recombinant swine interleukin-6

The swine interleukin-6 (SwIL-6) cDNA was cloned by RT-PCR and each expression system of recombinant SwIL-6 in Escherichia coli, insect cells, and mammalian cells was developed. Recombinant SwIL-6 produced in bacteria was applied for generation of the polyclonal antibodies. The rSwIL-6 was purified from supernatant of insect cells with a Q-sepharose or anti-SwIL-6 monoclonal antibody based immunoaffinity column. The antibodies showed that the molecular weight of rSwIL-6 was approximately 26kDa in E. coli, 25, 26, 30kDa in insect cells, and 26 and 30kDa in mammalian cells. These variations of molecular weight were probably due to the different modifications of glycosylation. All these recombinant proteins retained the antigenicity and biological activity on 7TD1 mouse cells.

Characterization of specific antibodies and the establishment of sandwich ELISA and ELISPOT systems for swine IL-4

We produced four monoclonal antibodies (mAb) and two polyclonal antibodies using the purified cytokine expressed in bacteria and characterized them. Specific binding of each of the mAb and polyclonal antibodies to recombinant swine IL-4 (rSwIL-4) purified from Escherichia coli and baculovirus was demonstrated in an indirect ELISA and/or in western blotting. We established a sandwich enzyme-linked immunosorbent assay (ELISA) for measuring concentration of SwIL-4 in biological samples and established an enzyme-linked immunospot (ELISPOT) assay for detecting IL-4-secreting cells using a mAb and a polyclonal IgG from goat. The detection limit of the sandwich ELISA for SwIL-4 was 78 pg/ml. Using sandwich ELISA, SwIL-4 was detected in the bronchoalveolar lavage fluid (BALF) of pigs experimentally infected with Mycoplasma hyopneumoniae and could quantitate in supernatants of mitogen-stimulated PBMC culture. The ELISPOT system is useful for the detection of IL-4 producing cells in swine PBMC culture.

Rinderpest virus H protein: role in determining host range in rabbits

A major molecular determinant of virus host-range is thought to be the viral protein required for cell attachment. We used a recombinant strain of Rinderpest virus (RPV) to examine the role of this protein in determining the ability of RPV to replicate in rabbits. The recombinant was based on the RBOK vaccine strain, which is avirulent in rabbits, carrying the haemagglutinin (H) protein gene from the lapinized RPV (RPV-L) strain, which is pathogenic in rabbits. The recombinant virus (rRPV-lapH) was rescued from a cDNA of the RBOK strain in which the H gene was replaced with that from the RPV-L strain. The recombinant grew at a rate equivalent to the RPV-RBOK parental virus in B95a cells but at a lower rate than RPV-L. The H gene swap did not affect the ability of the RBOK virus to act as a vaccine to protect cattle against virulent RPV challenge. Rabbits inoculated with RPV-L became feverish, showed a decrease in body weight gain and leukopenia. High virus titres and histopathological lesions in the lymphoid tissues were also observed. Clinical signs of infection were never observed in rabbits inoculated with either RPV-RBOK or with rRPV-lapH; however, unlike RPV-RBOK, both RPV-L and rRPV-lapH induced a marked antibody response in rabbits. Therefore, the H protein plays an important role in allowing infection to occur in rabbits but other viral proteins are clearly required for full RPV pathogenicity to be manifest in this species.

Versatility and specificity in flavoenzymes: control mechanisms of flavin reactivity

Flavoenzymes are characterized by their remarkable versatility and strict specificity. The former can be grasped when flavoenzymes are treated as a whole, while the latter refers to each flavoenzyme in which the broad versatility of flavin is specifically controlled. The versatility stems from the variety of the redox, ionic, and electronic states that the flavin ring system can adopt. Versatility of flavoenzymes is reflected in their classification, which has generally been based on substrates and reactions catalyzed. A different classification is presented according to the number of electrons transferred in the reductive and oxidative half reactions. Specificity of each flavoenzyme is understood in terms of the regulatory mechanism of the broad reactive potentiality of flavin. The elements of this regulatory mechanism include hydrogen-bonding network, electrostatic effect, charge-transfer interaction, positioning between a substrate/ligand and flavin, and modulation of resonance hybridization, each of which is explained with relevant examples provided mainly by studies from the author's group.

Crystallization and preliminary X-ray characterization of rat liver acyl-CoA oxidase

A recombinant form of the flavoenzyme acyl-CoA oxidase from rat liver has been crystallized by the hanging-drop vapour-diffusion technique using PEG 20 000 as a precipitating agent. The crystals grew as yellow prisms, with unit-cell parameters a = 71.05, b = 87.29, c = 213.05 A, alpha = beta = gamma = 90 degrees. The crystals exhibit the symmetry of space group P2(1)2(1)2(1) and are most likely to contain a dimer in the asymmetric unit, with a V(M) value of 2.21 A(3) Da(-1). The crystals diffract to a resolution of 2.5 A at beamline BL6A of the Photon Factory. Two heavy-atom derivatives have been identified.

On the ligands in charge-transfer complexes of porcine kidney flavoenzyme D-amino acid oxidase in three redox states: a resonance Raman study

To investigate the structural modulation of ligands and their interaction in the active-site nanospace when they form charge-transfer (CT) complexes with D-amino acid oxidase (DAO) in three redox states, we compared Raman bands of the ligands in complex with DAO with those of ligands free in solution. Isotope-labeled ligands were synthesized for assignments of observed bands. The COO(-) stretching of ligands observed around, 1,370 cm(-1) downshifted by about 17 cm(-1) upon complexation with oxidized, semiquinoid and reduced DAO, except for the case of reduced DAO-N-methylisonicotinate complex (8 cm(-1) downward shift); the interaction mode of the carboxylate group with the guanidino group of Arg283 and the hydroxy moiety of Tyr228 of DAO is similar in the three redox states. The C=N stretching mode (1,704 cm(-1)) of Delta(1)-piperideine-2-carboxylate (D1PC) downshifted to 1,675 and 1,681 cm(-1) upon complexation with reduced and semiquinoid DAO, respectively. The downward shifts indicate that the C=N bond is weakened upon the complexation. This is probably due mainly to charge-transfer (CT) interaction between D1PC and semiquinoid or reduced flavin, i.e., the partial electron donation from the highest occupied molecular orbital (HOMO) of reduced flavin or a singly occupied molecular orbital (SOMO) of semiquinoid flavin to the lowest unoccupied molecular orbital (LUMO), an antibonding orbital, of D1PC. This speculation was supported by the finding that the magnitude of the shift is smaller by 5 cm(-1) (observed at 1,680 cm(-1)) in the case of reduced DAO reconstituted with 7,8-Cl(2)-FAD, whose reduced form has lower electron-donating ability than natural reduced FAD. The amount of electron flow was estimated by applying the theory of Friedrich and Person [(1966) J. Chem. Phys. 44, 2166-2170] to these complexes; the amounts of charge transfer from reduced FAD and reduced 7,8-Cl(2)-FAD to D1PC were estimated to be about 10 and 8% of one electron, respectively, in the CT complexes of reduced DAO with D1PC.

Gene for porcine pregnancy-associated glycoprotein 2 (poPAG2): its structural organization and analysis of its promoter

The pregnancy-associated glycoproteins (PAG) are abundant secretory products of the placental trophectoderm of ungulate species. They are structurally related to pepsin, having the capability to bind peptides. However, many cannot function as enzymes due to amino acid substitutions in and around the catalytic site. Here, we demonstrate that pigs, like cattle and sheep, but unlike equids, have multiple PAG genes. One of the transcribed porcine PAG (poPAG) genes, the one for poPAG2, was cloned. It had a nine-exon organization similar to that of other mammalian aspartic proteinase genes with an atypical TATA sequence. A total of 1.2 kbp upstream from exon 1 was sequenced. This region shared identity (> 65%) with the promoter regions of the bovine (bo) PAG1, boPAG2 and equine (eq) PAG genes, but not with other aspartyl proteinase genes, including that of pepsinogen A. Nor were there clear similarities to the promoters of other genes with trophoblast-specific expression. Of the different poPAG2 promoter constructs tested in transfection experiments in two human (JAr and JEG3) and one rat (Rcho) choriocarcinoma cell lines, only the shortest (-149 bp) was required to provide full expression of a luciferase reporter. Although this short promoter was not active in Cos-1 and L-929 cells, it was active in CHO cells, a transformed non-trophoblast hamster ovarian cell line. Co-transfection of Ets2 elevated the activity of this short promoter approximately six-fold in JAr cells, but, disruption of the two putative Ets sites did not alter the ability of Ets2 to transactivate the promoter. In the non-trophoblast cell lines, Ets2 failed to elicit any response. Ets2 responsiveness may be a common feature of most or all trophoblast-expressed genes, although in the case of poPAG2, the effect may be indirect.

Seroepidemiological survey of distemper virus infection in the Caspian Sea and in Lake Baikal

Forty Caspian seals were surveyed seroepidemiologically between 1993 and 1998 around the times of mass mortality that occurred in 1997 in the Caspian Sea and seven Baikal seals were also surveyed in 1998. Virus neutralizing tests and ELISA clearly suggested that distemper virus epidemic was caused in Caspian seals before the spring of 1997 and that CDV infection continued to occur in Lake Baikal in recent years.

Human CC chemokine liver-expressed chemokine/CCL16 is a functional ligand for CCR1, CCR2 and CCR5, and constitutively expressed by hepatocytes

Liver-expressed chemokine (LEC)/CCL16 is a human CC chemokine selectively expressed in the liver. Here, we investigated its receptor usage by calcium mobilization and chemotactic assays using mouse L1.2 pre-B cell lines stably expressing a panel of 12 human chemokine receptors. At relatively high concentrations, LEC induced calcium mobilization and chemotaxis via CCR1 and CCR2. LEC also induced calcium mobilization, but marginal chemotaxis via CCR5. Consistently, LEC was found to bind to CCR1, CCR2 and CCR5 with relatively low affinities. The binding of LEC to CCR8 was much less significant. In spite of its binding to CCR5, LEC was unable to inhibit infection of an R5-type HIV-1 to activated human peripheral blood mononuclear cells even at high concentrations. In human liver sections, hepatocytes were strongly stained by anti-LEC antibody. HepG2, a human hepatocarcinoma cell line, was found to constitutively express LEC. LEC was also present in the plasma samples from healthy adult donors at relatively high concentrations (0.3--4 nM). Taken together, LEC is a new low-affinity functional ligand for CCR1, CCR2 and CCR5, and is constitutively expressed by liver parenchymal cells. The presence of LEC in normal plasma at relatively high concentrations may modulate inflammatory responses.

Molecular properties of the matrixprotein(M) gene of the lapinized rinderpest virus

The nucleotide sequence of the matrixprotein (M) gene of the lapinized rinderpest virus (RPV-L) was determined. The full-length cDNA of the RPV-L M gene is composed of 1460 base pairs and is supposed to contain an open reading frame of 1005 nucleotides encoding on M protein of 335 amino acids. The homology of the predicted amino acid among congeneric morbilliviruses such as RPV Kabete 'O' strain (wild strain of RPV), RPV RBOK strain (vaccine strain of RPV for cattle), measles virus (MV), and canine distemper virus (CDV), is approximately 94%, 93%, 87% and 77%, respectively. In the present study, all coding regions of the RPV-L strain have been determined.

Organization of the chemokine genes in the human and mouse major clusters of CC and CXC chemokines: diversification between the two species

Chemokines are a family of small cytokines that play essential roles in the directed migration of various types of leukocytes. Based on the arrangement of the conserved cysteine residues, they are classified into two major subfamilies, CXC and CC, and two minor subfamilies, C and CX3C. So far, more than 40 members of this family have been identified in humans. Strikingly, the majority of CXC chemokine genes and that of CC chemokine genes are closely clustered at chromosomes 4q12-21 and 17q11.2, respectively. Similarly, the mouse major CXC and CC chemokine gene clusters are located on chromosomes 5 and 11, respectively. In order to understand the evolutionary processes that generated large numbers of CXC and CC chemokine genes in the respective chromosomal sites, we have constructed BAC and YAC contigs covering the human and mouse major clusters of CXC and CC chemokine genes. The results reveal that the organizations of CXC and CC chemokine genes in the major clusters are quite diverged between the two species most probably due to very recent gene duplications and rearrangements. Our results provide an important insight into the evolutionary processes that generated the major chemokine gene clusters and also valuable information in assigning the orthologues between human and mouse major cluster chemokines.

Carbohydrate-protein interactions between HNK-1-reactive sulfoglucuronyl glycolipids and the proteoglycan lectin domain mediate neuronal cell adhesion and neurite outgrowth

Lecticans, a family of chondroitin sulfate proteoglycans, represent the largest group of proteoglycans expressed in the nervous system. We previously showed that the C-type lectin domains of lecticans bind two classes of sulfated cell surface glycolipids, sulfatides and HNK-1-reactive sulfoglucuronylglycolipids (SGGLs). In this paper, we demonstrate that the interaction between the lectin domain of brevican, a nervous system-specific lectican, and cell surface SGGLs acts as a novel cell recognition system that promotes neuronal adhesion and neurite outgrowth. The Ig chimera of the brevican lectin domain bind to the surface of SGGL-expressing rat hippocampal neurons. The substrate of the brevican chimera promotes adhesion and neurite outgrowth of hippocampal neurons. The authentic, full-length brevican also promotes neuronal cell adhesion and neurite outgrowth. These activities of brevican substrates are neutralized by preincubation of cells with HNK-1 monoclonal antibodies and by pretreatment of the brevican substrates with purified SGGLs. Brevican and HNK-1 carbohydrates are coexpressed in specific layers of the developing hippocampus where axons from entorhinal neurons elongate. Our observations suggest that cell surface SGGLs and extracellular lecticans comprise a novel cell-substrate recognition system operating in the developing nervous system.

Brevican is degraded by matrix metalloproteinases and aggrecanase-1 (ADAMTS4) at different sites

Brevican is a member of the lectican family of chondroitin sulfate proteoglycans that is predominantly expressed in the central nervous system. The susceptibility of brevican to digestion by matrix metalloproteinases (MMP-1, -2, -3, -7, -8, -9, -10, and -13 and membrane type 1 and 3 MMPs) and aggrecanase-1 (ADAMTS4) was examined. MMP-1, -2, -3, -7, -8, -10, and -13 degraded brevican into a few fragments with similar molecular masses, whereas the degradation products of aggrecanase-1 had apparently different sizes. NH(2)-terminal sequence analyses of the digestion fragments revealed that cleavages of the brevican core protein by these metalloproteinases occurred commonly within the central non-homologous domain. MMP-1, -2, -3, -7, -8, -10, and -13 preferentially attacked the Ala(360)-Phe(361) bond, whereas aggrecanase-1 cleaved the Glu(395)-Ser(396) bond, which are similar to the cleavage sites observed with cartilage proteoglycan (aggrecan) for the MMPs and aggrecanase-1, respectively. These data demonstrate that MMP-1, -2, -3, -7, -8, -10, and -13 and aggrecanase-1 digest brevican in a similar pattern to aggrecan and suggest that they may be responsible for the physiological turnover and pathological degradation of brevican.

A region of the sulfonylurea receptor critical for a modulation of ATP-sensitive K(+) channels by G-protein betagamma-subunits

To determine the interaction site(s) of ATP-sensitive K(+) (K(ATP)) channels for G-proteins, sulfonylurea receptor (SUR2A or SUR1) and pore-forming (Kir6.2) subunits were reconstituted in the mammalian cell line, COS-7. Intracellular application of the G-protein betagamma2-subunits (G(betagamma)(2)) caused a reduction of ATP-induced inhibition of Kir6.2/SUR channel activities by lessening the ATP sensitivity of the channels. G(betagamma)(2) bound in vitro to both intracellular (loop-NBD) and C-terminal segments of SUR2A, each containing a nucleotide-binding domain (NBD). Furthermore, a single amino acid substitution in the loop-NBD of SUR (Arg656Ala in SUR2A or Arg665Ala in SUR1) abolished the G(betagamma)(2)-dependent alteration of the channel activities. These findings provide evidence that G(betagamma) modulates K(ATP) channels through a direct interaction with the loop-NBD of SUR.

Nonepisodic angioedema associated with eosinophilia: report of 4 cases and review of 33 young female patients reported in Japan

BACKGROUND

In 1984, Gleich et al. described 4 patients with episodic angioedema associated with eosinophilia (EAE), which was characterized by recurrent episodes of angioedema and urticaria, eosinophilia, elevated serum IgM, fever, increased body weight and a benign course without involvement of the internal organs demonstrating that it was a clinical entity distinct from the hypereosinophilic syndrome. Thereafter, 37 cases of EAE have been reported in Japan, 33 cases of which, although similar, had a different evolution from classical EAE.

OBJECTIVE

To describe 4 cases and review the cases of angioedema associated with eosinophilia reported in Japan.

RESULTS

Four Japanese female patients had persistent angioedema mainly involving the hands and lower legs, and eosinophilia which resolved within a few months. The review of the 37 cases of EAE in the Japanese literature demonstrated that in 33 cases, there were common characteristics which differed from EAE. These included: (1) the absence of recurrent attacks; (2) the predominance of young females (20-37 years, with a mean of 26 years); (3) the localization of the angioedema to the extremities; (4) the absence of increase in the serum IgM level, and (5) the effectiveness of low-dose prednisone or even the occurrence of spontaneous remission.

CONCLUSION

We propose that persistent angioedema with eosinophilia can be classified into 2 types, i.e. one being an episodic (recurrent) type as reported by Gleich and a nonepisodic type as our 4 cases and others found in the Japanese literature.

Substrate recognition and activation mechanism of D-amino acid oxidase: a study using substrate analogs

We investigated the mechanism of recognition and activation of substrate by D-amino acid oxidase (DAO) by thermodynamical and spectrophotometric methods using zwitterionic ligands [N-methylisonicotinate (NMIN), trigonelline, and homarine] and monoanionic ligands as model compounds of the substrate and the product. In terms of the charge within the substrate D-amino acid, monoanionic (e.g., benzoate), zwitterionic (e.g., NMIN), and dianionic (e.g., terephthalate) ligands are thought to be good models for neutral, basic, and acidic amino acids, respectively, because when a substrate binds to DAO, as previously reported, the a-ammonium group (-NH(3)(+)) probably loses a proton to become neutral (-NH(2)) before the oxidation. Zwitterionic ligands can also be good model compounds of product in the purple complex (the complex of reduced DAO with the product imino acid), because the imino nitrogen of the imino acid is in a protonated cationic form. We also discuss electrostatic interaction, steric effect, and charge-transfer interaction as factors which affect the affinity of substrate/ligand for DAO. Monoanionic ligands have high affinity for neutral forms of oxidized and semiquinoid DAO, while zwitterionic ligands have high affinity for anionic forms of oxidized, semiquinoid, and reduced DAO; this difference was explained by the electrostatic interaction in the active site. The low affinity of homarine (N-methylpicolinate) for oxidized DAO, as in the case of o-methylbenzoate, is due to steric hindrance: one of the ortho carbons of benzoate is near the phenol carbons of Tyr228 and the other ortho carbon is near the carbonyl oxygen of Gly313. The correlation of the affinity of meta- and para-substituted benzoates for oxidized DAO with their Hammet's s values are explained by the HOMO-LUMO interaction between the phenol group of Tyr224 and the benzene ring of benzoate derivative. The pK(a) of neutral flavin [N(3)-H of oxidized flavin, N(5)-H of semiquinoid flavin, and N(1)-H of reduced flavin] decreases by its binding to the apoenzyme. The magnitude of the decrement is oxidized flavin < semiquinoid flavin < reduced flavin. The largest factor in the substantially low pK(a) of reduced flavin in DAO is probably the steric hindrance between the hydrogen atom of H-N(1)(flavin) and the hydrogen atom of H-N of Gly315, which becomes significant when a hydrogen is bound to N(1) of flavin.

Three-dimensional structure of the purple intermediate of porcine kidney D-amino acid oxidase. Optimization of the oxidative half-reaction through alignment of the product with reduced flavin

The three-dimensional structure of the purple intermediate of porcine kidney D-amino acid oxidase (DAO) was solved by cryo-X-ray crystallography; the purple intermediate is known to comprise a complex between the dehydrogenated product, an imino acid, and the reduced form of DAO. The crystalline purple intermediate was obtained by anaerobically soaking crystals of oxidized DAO in a buffer containing excess D-proline as the substrate. The dehydrogenated product, delta(1)-pyrrolidine-2-carboxylate (DPC), is found sandwiched between the phenol ring of Tyr 224 and the planar reduced flavin ring. The cationic protonated imino nitrogen is within hydrogen-bonding distance of the backbone carbonyl oxygen of Gly 313. The carboxyl group of DPC is recognized by the Arg 283 guanidino and Tyr 228 hydroxyl groups through ion-pairing and hydrogen-bonding, respectively. The (+)HN=C double bond of DPC overlaps the N(5)-C(4a) bond of reduced flavin. The electrostatic effect of the cationic nitrogen of DPC is suggested to shift the resonance hybridization of anionic reduced flavin toward a canonical form with a negative charge at C(4a), thereby augmenting the electron density at C(4a), from which electrons are transferred to molecular oxygen during reoxidation of reduced flavin. The reactivity of reduced flavin in the purple intermediate, therefore, is enhanced through the alignment of DPC with respect to reduced flavin.

[Chemical and functional properties of flavin coenzymes]

The yellow-colored compounds with the basic structural frame work of 7,8-dimethyl-10-alkylisoalloxazine are generally termed as flavins. The 10-ribityl derivative, riboflavin, is the most abundant flavin found in nature and is known as vitamin B2. Riboflavin is a precursor of the flavocoenzymes, FMN (flavin mononucleotide) and FAD (flavin adenine dinucleotide) which function as prosthetic groups of flavocoenzymes. While flavocoenzymes are usually bound noncovalently to apoproteins of flavoenzymes, covalently-bound flavocoenzymes also occur in nature, though much less often. Flavin molecules can exist in three different redox states, i.e., oxidized, one-electron reduced and two-electron reduced states, and therefore can participate in redox reactions as either one- or two-electron mediator, making the flavoenzymes extremely versatile in terms of substrate and type of reactions catalyzed. We classified flavoenzymes according to the electron-transfer process in their reductive and oxidative half-reactions and the mechanism of each class of flavoenzymes is discussed in detail.

Asymmetry and direction reversal in fluctuation-induced biased Brownian motion

The biased movement of a Brownian particle in a periodic potential fluctuating between a flat and a kinked ratchet state, as first studied by Chauwin, Ajdari, and Prost, is examined. The purpose is to study the physical origin of the frequency-dependent direction reversal of the biased Brownian motion in this system. We show that the existence of the directional reversal depends not only on the lengths of the projections of the two ratchet arms on the potential axis (the arm-projection asymmetry), but also the overall spatial geometry of the potential in a period. In particular, we show that the direction reversal can be obtained in this kinked ratchet model even when the two arm projections are equal. Since this two-state model is the simplest to generate direction reversal and particles can be separated more efficiently in a fluctuating potential if direction reversal exists, the results obtained in this study should be useful for future application in particle separation.

Unusually high standard redox potential of acrylyl-CoA/propionyl-CoA couple among enoyl-CoA/acyl-CoA couples: a reason for the distinct metabolic pathway of propionyl-CoA from longer acyl-CoAs

The standard redox potential of acrylyl-CoA/propionyl-CoA couple (C(3)) was determined to be 69 mV (vs. standard hydrogen electrode) at pH 7 and 25 degrees C. This value implies that the 2, 3-dehydrogenation of propionyl-CoA is thermodynamically much more unfavorable than that of longer acyl-CoAs because the standard redox potentials of crotonyl-CoA/butyryl-CoA (C(4)), octenoyl-CoA/octanoyl-CoA (C(8)), and hexadecenoyl-CoA/palmitoyl-CoA (C(16)) are all about -10 mV. The unusually high standard redox potential of the acrylyl-CoA/propionyl-CoA couple is thought to be one of the reasons that in mammals propionyl-CoA is not metabolized by beta-oxidation as in the case of longer acyl-CoAs, but by a methylmalonyl-CoA pathway. The obvious structural difference between C(3) and C(4) (and longer) is whether an H or the C(4) atom is connected to -C(3)H=C(2)H-C(1)O-S-CoA. The molecular orbital calculations (MOPAC) for the enoyl and acyl forms of C(3) and C(4) revealed that this structural feature is the main cause for the higher standard redox potential of the C(3) couple. That is, the C(4)-C(3) bond is stabilized by the dehydrogenation to a greater degree than the H-C(3) bond.

Immunohistochemical evidence for the brevican-tenascin-R interaction: colocalization in perineuronal nets suggests a physiological role for the interaction in the adult rat brain

Brevican is one of the most abundant chondroitin sulfate proteoglycans in the adult rat brain. We have recently shown that the C-type lectin domain of brevican binds fibronectin type III domains 3-5 of tenascin-R. Here we report strong evidence for a physiological basis for this interaction. Substantial brevican immunoreactivity was detected in a number of nuclei and in the reticular formations throughout the midbrain and hindbrain, including, but not limited to, the deep cerebellar nuclei, the trapezoid body, the red nucleus, the oculomotor nucleus, the vestibular nucleus, the cochlear nucleus, the gigantocellular reticular nucleus, the motor trigeminal nucleus, and the lateral superior olive. Most of the brevican immunoreactivity exhibited pericellular and reticular staining patterns. In almost all of these sites, brevican immunoreactivity colocalized with that of tenascin-R, which was also substantially codistributed with versican, another member of the lectican family. Detailed analysis revealed that the pericellular staining of brevican resembled that in perineuronal nets in which tenascin-R has been localized. Immunoelectron microscopy identified brevican immunoreactivity in the intercellular spaces surrounding presynaptic boutons and on their surfaces, but not in the synaptic clefts or in their immediate vicinity, a distribution pattern consistent with perineuronal nets. Taken together, our results provide strong evidence that the previously reported interactions between brevican and tenascin-R may play a functional role within the perineuronal nets.

The proteoglycan lectin domain binds sulfated cell surface glycolipids and promotes cell adhesion

The lecticans are a group of chondroitin sulfate proteoglycans characterized by the presence of C-type lectin domains. Despite the suggestion that their lectin domains interact with carbohydrate ligands, the identity of such ligands has not been elucidated. We previously showed that brevican, a nervous system-specific lectican, binds the surface of B28 glial cells (Yamada, H., Fredette, B., Shitara, K., Hagihara, K., Miura, R., Ranscht, B., Stallcup, W. B., and Yamaguchi, Y. (1997) J. Neurosci. 17, 7784-7795). In this paper, we demonstrate that two classes of sulfated glycolipids, sulfatides and HNK-1-reactive sulfoglucuronylglycolipids (SGGLs), act as cell surface receptors for brevican. The lectin domain of brevican binds sulfatides and SGGLs in a calcium-dependent manner as expected of a C-type lectin domain. Intact, full-length brevican also binds both sulfatides and SGGLs. The lectin domain immobilized as a substrate supports adhesion of cells expressing SGGLs or sulfatides, which was inhibited by monoclonal antibodies against these glycolipids or by treatment of the substrate with SGGLs or sulfatides. Our findings demonstrate that the interaction between the lectin domains of lecticans and sulfated glycolipids comprises a novel cell substrate recognition system, and suggest that lecticans in extracellular matrices serve as substrate for adhesion and migration of cells expressing these glycolipids in vivo.

Genomic organization of the genes for human and mouse CC chemokine LEC

Liver-expressed chemokine (LEC) is a CC chemokine that is selectively expressed in the liver. We report here the structures of the human and mouse genes for LEC. The human LEC gene (SCYA16) was isolated from a bacterial artificial chromosome (BAC) clone that also contained CC chemokine genes for MPIF-1/Ckbeta8, HCC-2/Lkn-1/MIP-5/MIP-1delta, and HCC-1. The LEC gene is approximately 5.0 kb in length and has a three-exon and two-intron structure common to most CC chemokine genes. However, the promoter region is devoid of a typical TATA box, and transcription initiates at multiple sites. The gene for CC chemokine HCC-1, which is most similar to LEC, is located approximately 2.2 kb upstream from the 5' end of the LEC gene in a head-to-tail fashion. The mouse DNA fragment that hybridized with the human LEC cDNA was isolated from a BAC clone that also contained the CC chemokine genes for C10, MRP-2/CCF18/MIP-1gamma, and RANTES. Sequence analysis revealed that the isolated gene does not encode a functional chemokine because of deletions, insertions, and base changes. Southern blot analysis revealed that the sequence isolated from the BAC clone was the only one hybridizing with human LEC cDNA in the mouse genome. Therefore, mice may have only an LEC pseudogene.

Organization of the chemokine gene cluster on human chromosome 17q11.2 containing the genes for CC chemokine MPIF-1, HCC-2, HCC-1, LEC, and RANTES

To understand the organization of the human CC chemokine gene cluster on chromosome 17q11.2, we determined the nucleotide sequence of a region 181 kb long containing five CC chemokine genes, MPIF-1 (SCYA23), HCC-2 (SCYA15), HCC-1 (SCYA14), LEC (SCYA16), and RANTES (SCYA5), by the random shot-gun method. The four CC chemokine genes, MPIF-1, HCC-2, HCC-1, and LEC, are clustered within a region 40 kb long, whereas the RANTES gene is located approximately 10 kb apart from the four chemokine gene minicluster. These chemokine genes are arranged in the same orientation, and their sizes are relatively long, 3.1 (HCC-1)-8.8 kb (RANTES) when compared with other CC chemokine genes, such as MIP-1alpha/LD78alpha (SCYA3) (1.9 kb) and MCP-1 (SCYA2) (1.5 kb). In contrast to most other human CC chemokine genes that consist of three exons, the MPIF-1 and HCC-2 genes, separated by 12 kb, have four exons. When the nucleotide sequences of the MPIF-1 and HCC-2 genes are compared, they are well conserved, including introns and flanking sequences, except for the middle region of the long first intron, indicating that they have been generated recently in evolutionary terms by duplication. In addition to the CC chemokine genes, more than 30 exons are identified in the sequenced region by similarity search against expressed sequence tags (ESTs) and also by the gene prediction program GenScan. This indicates that the chemokine cluster sequenced in this study is a gene-rich region in the human genome.

Amino acid residues in the transmembrane domain of the type 1 sigma receptor critical for ligand binding

The type 1 sigma receptor expressed in Xenopus oocytes showed binding abilities for the sigma-1 ligands, [3H](+)pentazocine and [3H]NE-100, with similar kinetic properties as observed in native tissue membranes. Amino acid substitutions (Ser99Ala, Tyr103Phe and di-Leu105,106di-Ala) in the transmembrane domain did not alter the expression levels of the type 1 sigma receptor as determined by immunoblot analysis using an anti-type 1 sigma receptor antiserum. By contrast, ligand binding was significantly suppressed by the substitutions. These findings provide evidence that the transmembrane domain of the type 1 sigma receptor plays a critical role in ligand binding of this receptor.

Chemokine PARC gene (SCYA18) generated by fusion of two MIP-1alpha/LD78alpha-like genes

Two loci in the human genome, chromosomes 4q12-q21 and 17q11.2, contain clusters of CXC and CC chemokine subfamily genes, respectively. Since mice appear to contain fewer chemokine genes than humans, numerous gene duplications might have occurred in each locus of the human genome. Here we describe the genomic organization of the human pulmonary and activation-regulated CC chemokine (PARC), also known as DC-CK1 and AMAC-1. Despite high sequence similarity to a CC chemokine macrophage inflammatory protein-1alpha (MIP-1alpha)/LD78alpha, PARC is chemotactic for lymphocytes and not for monocytes and does not share its receptor with MIP-1alpha. Analyses of the BAC clones containing the human PARC gene indicated that the gene is located most closely to MIP-1alpha (HGMW-approved symbol SCYA3) and MIP-1beta (HGMW-approved symbol SCYA4) on chromosome 17q11.2. Dot-plot comparison suggested that the PARC gene had been generated by fusion of two MIP-1alpha-like genes with deletion and selective usage of exons. Base changes accumulated before and after the fusion might have adapted the gene to a new function. Since there are variably duplicated copies of the MIP-1alpha gene called LD78beta (HGMW-approved symbol SCYA3L) in the vicinity of the MIP-1alpha gene, the locus surrounding the MIP-1alpha gene seems to be a "hot spring" that continuously produces new family genes. This evidence provides a new model, duplication and fusion, of the molecular basis for diversity within a gene family.

Mechanism for the recognition and activation of substrate in medium-chain acyl-CoA dehydrogenase

The mechanism underlying the recognition and activation of the substrate for medium-chain acyl-CoA dehydrogenase (MCAD) was spectroscopically investigated using 3-thiaacyl-CoAs as substrate analogs. The complex of MCAD with 3-thiaoctanoyl-CoA (3-thia-C8-CoA) exhibited a charge-transfer (CT) band with a molar extinction coefficient of epsilon808 = 9.1 mM-1.cm-1. With increasing 3-thiaacyl-chain length, the CT-band intensity of the complex decreased concomitantly with changes in the FAD absorption at 416 and 482 nm, and no CT band was detected in complexes with chain-lengths longer than C15. Detailed analysis of the absorption spectra suggested that the complexed states represent a two-state equilibrium between the CT-inducing form and the CT-non-inducing form. 13C-NMR measurements with 13C-labeled ligand clarified that 3-thia-C8-CoA is complexed to MCAD in an anionic form with signals detected at 163.7 and 101.2 ppm for 13C(1) and 13C(2), respectively. In the MCAD complex with 13C(1)-labeled 3-thia-C12-CoA, two signals for the bound ligand were observed at 163.7 and 198.3 ppm, and assigned to the anionic and neutral forms, respectively. Only the neutral form signal was measured at 200.6 ppm in the complex with 13C(1)-labeled 3-thia-C17-CoA. These results indicate that the CT band can be explained in terms of an internal equilibrium between anionic (CT-inducing) and neutral (CT-non-inducing) forms of the bound ligand. Resonance Raman spectra of the MCAD.3-thia-C8-CoA complex, with excitation at the CT band, showed enhanced bands, among which the 854- and 1,368-cm-1 bands were assigned to the S-C(2) stretching mode of the ligand and to flavin band VII, respectively. Since the enhanced bands were observed at the same wave numbers in complexes with C8, C12, and C14-ligands, it appears that the CT-inducing form shares a common alignment relative to oxidized flavin irrespective of differences in the acyl-chain length. However, with longer ligands, the degree of resonance enhancement of the Raman bands decreased in parallel with the CT-band intensity; this is compatible with the increase in the CT-non-inducing form in complexes with longer ligands. Furthermore, the pH dependence of the CT band gave an apparent pKa = 5.6-5.7 for ligands with chain-lengths of C8-C12. The NMR measurements revealed that, like chain-length dependence, the pH dependence can be explained by a two-state equilibrium derived from the protonation/deprotonation of the CT-inducing form of the bound ligand. On the basis of these results we have established a novel model to explain the mechanism of recognition and activation of the substrates/ligands by MCAD.

C-terminal tripeptide Ser-Asn-Leu (SNL) of human D-aspartate oxidase is a functional peroxisome-targeting signal

The functionality of the C-terminus (Ser-Asn-Leu; SNL) of human d-aspartate oxidase, an enzyme proposed to have a role in the inactivation of synaptically released d-aspartate, as a peroxisome-targeting signal (PTS1) was investigated in vivo and in vitro. Bacterially expressed human d-aspartate oxidase was shown to interact with the human PTS1-binding protein, peroxin protein 5 (PEX5p). Binding was gradually abolished by carboxypeptidase treatment of the oxidase and competitively inhibited by a Ser-Lys-Leu (SKL)-containing peptide. After transfection of mouse fibroblasts with a plasmid encoding green fluorescent protein (GFP) extended by PKSNL (the C-terminal pentapeptide of the oxidase), a punctate fluorescent pattern was evident. The modified GFP co-localized with peroxisomal thiolase as shown by indirect immunofluorescence. On transfection in fibroblasts lacking PEX5p receptor, GFP-PKSNL staining was cytosolic. Peroxisomal import of GFP extended by PGSNL (replacement of the positively charged fourth-last amino acid by glycine) seemed to be slower than that of GFP-PKSNL, whereas extension by PKSNG abolished the import of the modified GFP. Taken together, these results indicate that SNL, a tripeptide not fitting the PTS1 consensus currently defined in mammalian systems, acts as a functional PTS1 in mammalian systems, and that the consensus sequence, based on this work and that of other groups, has to be broadened to (S/A/C/K/N)-(K/R/H/Q/N/S)-L.

Folding motifs induced and stabilized by distinct cystine frameworks

Bioactive peptides of different sources and biological functionalities, like endothelins, sarafotoxins, bee and scorpion venom toxins, contain a consensus cystine framework, Cys-(X)1-Cys/Cys-(X)3-Cys, which has been found to induce and stabilize a homologous folding motif named the cystine-stabilized alpha-helix (CSH). This is composed of an alpha-helical segment spanning the Cys-(X)3-Cys sequence portion that is crosslinked by two disulfide bridges to the sequence portion Cys-(X)1-Cys, itself folded in an extended beta-strand type structure. Search for sequence homologies of peptides and proteins in the SWISS-PROT and PDB data banks provided additional multiple examples of this type of cystine framework in serine proteinase inhibitors, in insect and plant defense proteins, as well as in members of the growth factor family with the cystine-knot. A comparative analysis of the known 3D-structures of these peptides and proteins confirmed that the presence of this peculiar cystine framework leads in all cases to a high degree of local structural homology that consists of the CSH motif, except for the cystine-knot, of the superfamily of the growth factors. In this case the cyclic structure formed by the parallel cysteine connectivities of Cys-(X)1-Cys/Cys-(X)3-Cys framework is penetrated by a third disulfide bond with formation of a concatenated knot, and the two disulfide-bridged peptide chains Cys-(X)1-Cys and Cys-(X)3-Cys are located in beta-strands. Conversely, peptides and proteins containing Cys-(X)m-Cys/Cys-(X)n-Cys cystine frameworks that differ from m/n = 1/3 were found to fold only sporadically into local alpha-helical structures.