A single homogeneous form of ATP6 protein accumulates in petunia mitochondria despite the presence of differentially edited atp6 transcripts

Transcripts encoding ATP synthase subunit 6 (ATP6) in petunia mitochondria were shown to be edited at 15 sites, leading to 14 amino acid changes. Certain sites are partially edited, including a site that introduces a new translation termination codon that is 13 codons upstream of the genomically encoded stop codon. Transcripts lacking the new stop codon are present in an approximately 2.5:1 ratio to transcripts carrying the stop codon created by RNA editing. To investigate whether partially edited transcripts are represented as proteins, we generated an antibody against a 12-residue peptide that is specific for translation products of unedited transcripts. This antibody did not recognize any ATP6 protein in either total mitochondrial protein preparations or ATP6 samples purified by organic solvent extraction and reverse phase HPLC procedures. According to analysis by mass spectrometry, only one form of ATP6 protein accumulates in mitochondria despite the presence of abundant partially edited transcripts. Partially edited atp6 transcripts were associated with ribosomes, suggesting that a screening mechanism(s) acts cotranslationally or post-translationally to exclude the expression of incompletely edited transcripts.

Staphylococcal protein A containing phospholipid monolayers on aqueous and solid surfaces

The staphylococcal protein A containing monolayer is characterized on both aqueous and solid surfaces. The density of SpA in dipalmitoylphosphatidic acid (DPPA) monolayers is determined from ultraviolet spectroscopy. The influence of calcium on the SpA concentration in the monolayer is also investigated. The spectroscopic results indicate that the incorporation of SpA in the monolayer is influenced by the calcium concentration in the subphase, and more than 90% of adsorbed protein is excluded from the monolayer when calcium concentration is in the order of millimoles. The IgG binding activity of the SpA in the reconstituted membrane is influenced by the surface pressure at which the membrane is formed.

Stress response of Porphyromonas gingivalis

The heat shock response of Porphyromonas gingivalis was examined by 1- and 2-dimensional polyacrylamide gel electrophoresis after metabolic labeling with [14C]-amino acids. When P. gingivalis cells were shifted from 37 degrees C to 42 degrees C, elevated synthesis of 4 proteins with the apparent molecular weight of 92, 80, 74, and 62 kDa was observed, and synthesis of a 50-kDa protein decreased during heat shock. The 74- and 62-kDa proteins were identified as homologs of Escherichia coli DnaK and GroEL respectively by Western immunoblotting. On 2-dimensional Western blots, 2 forms of DnaK and 4 forms of GroEL were identified due to their slightly different isolelectric points. dnaK and groEL gene homologs were identified in several P. gingivalis strains and some other black-pigmented oral species. DnaK and GroEL homolog proteins were induced when P. gingivalis cells were challenged by ethanol. These proteins were not induced by oxidative stress or change in pH.

Characterization of modified staphylococcal protein A containing phospholipid monolayer on both solution and slide surfaces

A method is described for incorporation of water-soluble protein Staphylococcal protein A (SpA) into phospholipid monolayer using covalent protein-lipid conjugates in detergent solution. The amphiphilic conjugates have solubility properties very similar to intergral membrane proteins. When the conjugates are applied into dipalmitoyl-phosphatidic acid monolayer, a protein containing monolayer is formed on subphase surface. The monolayer is transferred to pre-coated substrate surface to form an artificial membrane. Results show that unmodified SpA is readily ejected from the monolayer when compressing the monolayer but modified SpA incorporates into the monolayer stably. The incorporation of the protein is proportional to the lipid coupling degree. When the protein is excessively modified, the IgG binding activity of the SpA in the membrane is lost significantly.

Differentiation-specific expression of human keratin 1 is mediated by a composite AP-1/steroid hormone element

Human keratin 1 (HK1) expression is associated with the loss of mitotic activity in epidermal keratinocytes and restricted to an intermediate stage of terminal differentiation. Recently, the control elements that mediate this differentiation-specific expression were identified (Huff, C. A., Yuspa, S. H., and Rosenthal, D. (1993) J. Biol. Chem. 268, 377-384). We now report the characterization of one of these elements. Footprint analysis on a 249-base pair fragment containing the calcium responsive element (CaRE) revealed two adjacent protected regions. The 5' most footprint contains an AP-1 consensus sequence while the 3' footprint encodes two inverted repeats of the canonical hormone response recognition sequence. Deletion of the AP-1-protected region abolished the calcium response in a reporter construct. Calcium activation of the reporter construct containing the intact CaRE was unaffected by the addition of thyroid hormone or estrogen. However, vitamin D3 was able to suppress calcium induction by the CaRE, and this suppression could be abrogated by the coaddition of retinoic acid. These studies show that AP-1 factors bind to the 5' element to mediate the calcium response while members of the steroid hormone receptor superfamily interact with the 3' element to modulate the calcium response.

Functional characterization of the rat GAP-43 promoter

GAP-43 is a highly conserved neuronal protein whose expression is spatially and temporally regulated. Because this regulation may occur, at least in part, at the level of transcription, we have begun to characterize the regions upstream of the GAP-43 transcription unit which direct its neuronal-specific expression. Functional analyses of GAP-43 promoter-reporter constructs have been performed in stably transfected cell lines, including PC12, C6 and RAT2. These data indicate that as little as 600 bp of GAP-43 5'-flanking DNA sequence directs the expression in a neuronal-specific manner. A shorter construct containing 230 bp of 5'-flanking DNA sequence defines a GAP-43 minimal promoter that is active in both neuronal and glial but not in non-neural cell lines. An upstream region, previously shown by other investigators to have promoter activity, was able to stimulate transcription when linked to the downstream minimal promoter. However, this upstream region was by itself unable to direct transcription of the reporting gene. In addition, we have demonstrated that two polypurine tracts within the 5'-flanking DNA sequence of the GAP-43 gene adopt a non-duplex configuration in plasmids, and, when studied in the context of chromosomal integration, these regions have a stimulatory effect on transcription.

Motion observed across maxillary continuity defects stabilized with plates and screws

The stability of fixation obtained with internal fixation devices (plates and screws) under functional loading of maxillary continuity defects was studied using fresh cadaver skulls. Micromotion (deformation) was recorded in the model across the level of the LeFort I osteotomies even when fixation was thought to be grossly stable. Deformation in this biologically static model proved to be mostly elastic in nature, and the amount of deformation in each skull appeared to be predictable from the average stability of all screws used in each plate. Such motion in viable bone could lead to permanent deformation due to resorption and remodeling of bone around the screws if initial overall fixation stability is tenuous. The results suggest that the term "rigid" is inappropriately used to describe plate and screw fixation of maxillary continuity defects.

[Study on compound levonorgestrel microspheres]

Levonorgestrel (LNG) and estradiol (E2) were mixed in the ratio of 5:2 by weight. Compound LNG gelatin-microspheres were prepared by phase-separation method, natural biodegradable gelatin being used as the core material. The experimental conditions were optimized, the mean diameter of the microspheres obtained being 10-40 microns, and the rate of encapsulation 65-75%. Storage observations and acceleration tests of the compound LNG gelatin-microsphere injection prepared showed that the microspheres have good stability. The thermal degradation activation energy of the injection was determined to be 134.4 kJ/mol, based on differential scanning colorimetry (DSC). T1/2 values for dissolution in vitro of LNG and E2 from the compound LNG gelatin-microsphere injection and from the unencapsulated injection showed significant difference (P < 0.01), indicating that the microspheres have good sustained release action. Effects of the pure LNG microsphere injection and compound LNG microsphere injection on the mouse ovary were compared histologically. The results showed that the compound LNG microsphere injection reduced some of the side effects such as ovary congestion. This points out that the compound dosage form can clinically alleviate the irregular bleeding caused by the administration of LNG alone.

Calcitonin gene-related peptide potentiates synaptic responses at developing neuromuscular junction

Protein phosphorylation is important in synaptic transmission and plasticity. At the neuromuscular junction, phosphorylation of acetylcholine (ACh) receptor-channels increases the rate of agonist-induced channel desensitization. In contrast, potentiation of ACh channel activity through protein phosphorylation has not been described. We report here that calcitonin gene-related peptide (CGRP), a neuropeptide present at presynaptic motor nerve terminals, enhances the postsynaptic response at developing neuromuscular junctions by increasing the burst duration of embryonic ACh channels. The effect of CGRP on these ACh channels is mimicked by dibutyryl-cyclic AMP and by cAMP-dependent protein kinase (PKA) and prevented by a specific peptide inhibitor of PKA. Moreover, postsynaptic inhibition of PKA reduced the amplitude and decay time of spontaneous synaptic currents, suggesting that endogenous CGRP may act as a potentiating factor during the early phase of synaptogenesis.

A histological study of the eye lesions in 12 leprosy patients with tuberculoid lesion in 4 eyes

The histological reactions in 12 eyes of 12 leprosy patients were studied (5 BT, 1 BB, 1 BL and 5 LL). Granuloma lesions composed of epithelioid cells, Langerhans giant cells, macrophages and lymphocytes were found in various intraocular tissues, e.g. cornea, sclera, iris, ciliary body or retina in 4 patients (1 BT and 3 LL). Of the 3 LL patients, according to the records, 2 were cured and in the other patient the outcome of the treatment was not mentioned. In view of the finding of the granulomatous lesions in the clinically cured patients and tuberculoid granuloma in the intraocular tissues in the LL patients, could there be some peculiarities in the intraocular sites? Or perhaps the tuberculoid reaction is just a manifestation of an upgrading reaction? More examinations on human leprosy eye specimens will be needed to answer these questions.

[Testicular tissue homotransplantation of newborn rat: experimental study]

32 newborn Sprague-Dawley rats were used as donors and 32 castrated male out-bred mature rats as recipients. The pieces of testes tissue were implanted subcutaneously in the bilateral hind legs. Two month follow-up showed that the grafts survived and increased in size. Serum testosterone levels of the recipients were higher than those of the castrated. They peaked and were close to the levels of the mature rats even 45 days after the implantation. Serum FSH, and, LH levels in the recipients were lower than those of the castrated. The mechanism of the newborn testes as an immuno-privileged donor is discussed.

[Studies on preparation technology of microspheres of contraceptives]

Contraceptive poly ethylglycol-lactide (PEGL), an artificial biodegradable polymer microsphere was prepared by a solvent evaporation process using levonorgestrel (LNG) and estradiol (E2) as model drugs and PEGL as the core material. The experimental conditions were optimized, the mean volume diameter obtained being 30 microns and rate of encapsulation 75-82%. In vitro, it was found that the drug release rate decreased with decreasing drug content in the microspheres. The microspheres of the contraceptive maintained anticonception duration in mice for over 6 months, indicating that the microspheres have remarkably long acting sustained release action.

A single nuclear gene specifies the abundance and extent of RNA editing of a plant mitochondrial transcript

A number of cytosines are altered to be recognized as uridines in transcripts of the NADH-dehydrogenase subunit 3 (nad3) gene in the mitochondria of the higher plant Petunia hybrida. Here we show that the extent of editing for three of the edit sites, all of which change the encoded amino acid, varies between different Petunia lines. Genetic analysis indicates that a single nuclear gene is responsible for this variation. Interestingly, according to RNA blot hybridization analysis, RNA editing extent and transcript abundance are correlated. This observation is consistent with the hypothesis that RNA editing is a post-transcriptional event.

Separation of glucuronides from urine by coupled-column separation using underivatized silica as precolumn

Glucuronides are separated from urine by coupled-column separations (CCSs). The fraction containing the glucuronide(s) is transferred on-line from a silica precolumn to the analytical column (octadecyl derivatized silica), enriched, and separated by ion-pair chromatography. The retention and selectivity on the precolumn are controlled by pH, buffer components, organic modifier, and ion-pair agent. After the injection of filtered urine samples, glucuronides with different chemical properties can be separated. The total analysis of morphine-3-glucuronide and morphine-6-glucuronide is accomplished in less than six minutes, with UV detection at 210 nm.

Calcium-Dependent Transmitter Secretion Reconstituted in Xenopus Oocytes: Requirement for Synaptophysin

Calcium-dependent glutamate secretion was reconstituted in Xenopus oocytes by injecting the oocyte with total rat cerebellar messenger RNA (mRNA). Co-injection of total mRNA with antisense oligonucleotides to synaptophysin message decreased the expression of synaptophysin in the oocyte and reduced the calcium-dependent secretion. A similar effect on secretion was observed for oocytes injected with total mRNA together with an antibody to rat synaptophysin. These results indicate that synaptophysin is necessary for transmitter secretion and that the oocyte expression system may be useful for dissecting the molecular events associated with the secretory process.

Short-term reproducibility over time of right ventricular pulse pressure as a potential hemodynamic sensor for ventricular tachyarrhythmias

The implantable cardioverter defibrillator (ICD) has been shown to effectively terminate episodes of ventricular tachyarrhythmias. Multiple investigators have suggested that the incorporation of hemodynamic sensors may allow ICDs to differentiate between hemodynamically unstable and stable ventricular tachyarrhythmias (VT), as well as differentiate ventricular from supraventricular tachycardias. Right ventricular (RV) pulse pressure has been shown to possess acceptable characteristics as a sensor for incorporation in ICDs. We sought to determine the short-term reproducibility of RV pulse pressure measurements by comparing RV pulse pressure measured during two separate episodes of VT in each of ten study patients. The mean VT cycle length for VT episode 1 was 293 +/- 15 msec, and was 298 +/- 15 msec for VT episode 2 (P = NS). The decrease in mean arterial pressure was 40 +/- 7 mmHg in episode 1 and 37 +/- 7 mmHg in episode 2 (P = NS). The decrease in RV pulse pressure during episode 1 was -13 +/- 2 mmHg, and -12 +/- 2 during episode 2 (P = NS). The decrease in RV pulse pressure during episodes of VT at two different times during a single electrophysiology study is highly reproducible, suggesting that RV pulse pressure may be a reliable sensor over time.

Cell-type-specific localization of transforming growth factor-beta 2 and transforming growth factor-beta 1 in the hamster ovary: differential regulation by follicle-stimulating hormone and luteinizing hormone

Cell-type-specific localization and gonadotropin regulation of transforming growth factor-beta 1 (TGF-beta 1) and transforming growth factor-beta 2 (TGF-beta 2) in the hamster ovary were evaluated immunohistochemically under three conditions: (1) during the estrous cycle (Day 1 = estrus; Day 4 = proestrus); (2) after the blockade of periovulatory gonadotropin surges by phenobarbital, and (3) after FSH and/or LH treatment of long-term hypophysectomized hamsters. Ovarian TGF-beta 1 activity was primarily localized in theca and interstitial cells. The activity increased moderately but significantly after the preovulatory LH surge and reached a peak at 0900 h, Day 2 h; oocytes showed considerable activity. TGF-beta 1 immunoreactivity subsequently fell to low levels in theca-interstitial cells through 0900 h, Day 4. Significant TGF-beta 2 immunoreactivity appeared after the surge, mainly in the granulosa cells of both preantral and antral follicles; a few interstitial cells surrounding preantral follicles showed discrete staining. TGF-beta 2 immunoreactivity in granulosa cells and in interstitial cells next to preantral follicles reached a peak at 0900 h, Day 1, and persisted up to 0900 h, Day 2; oocytes showed no staining. Phenobarbital treatment blocked the appearance of TGF-beta 1 and TGF-beta 2 immunoreactivities at 1600 h, Day 4; however, a rebound in immunoreactivities was observed with the onset of the surge after a 1-day delay. Replacement of LH to long-term hypophysectomized hamsters resulted in a marked increase in TGF-beta 1 immunoreactivity in the interstitial cells, but FSH, although it induced follicular development, did not influence ovarian TGF-beta 1 activity. Treatment with FSH, however, induced a massive increase in TGF-beta 2 immunoreactivity in the granulosa cells of newly developed antral and preantral follicles but not in the interstitial cells; LH, on the other hand, had no significant effect on TGF-beta 2 activity. Treatment with FSH and LH combined resulted in a dramatic increase in TGF-beta 2 immunoreactivity in granulosa and interstitial cells and in TGF-beta 1 in theca and interstitial cells comparable to their peak activity in intact animals. Western analyses substantiated the presence of TGF-beta 1 and TGF-beta 2 in the hamster ovary and the specificity of immunolocalization. These studies, therefore, provide critical evidence that TGF-beta 1 and TGF-beta 2 in the hamster ovary are expressed in specific cell types and that their expression is differentially regulated by LH and FSH, respectively.

[Squamous metaplasia of the mucosa of the human laryngeal ventricle: a clinicopathological study with reference to the possibility of de novo carcinogenesis]

Primary carcinomas are rarely encountered in the laryngeal ventricle of Morgagni. They are classified into the subgroup of supraglottic laryngeal carcinoma in the TNM classification system of malignant tumors. However, detailed investigations have not hitherto been made on the possible occurrence of carcinomas in this region of the larynx. To find out whether the laryngeal ventricle could be the site of carcinogenesis, the author examined squamous metaplasia in the mucosal epithelium of 60 human laryngeal ventricles which were taken from 38 larynges removed operatively from patients with laryngeal carcinoma (14 cases), hypopharyngeal carcinoma (20 cases), carcinoma of the upper esophagus (two cases), tracheal carcinoma (one case) or thyroid carcinoma (one case). The patients consisted of 31 males and 7 females, with an age distribution of 44 to 80, average 62.7. The laryngeal ventricles were selected for investigation only when they did not show any carcinomatous invasion macroscopically. Macroscopic observations were performed after gross staining with pyronin Y, which permits differentiation of squamous metaplasia from respiratory epithelia. Tissues were embedded in paraffin, sectioned serially and stained with hematoxylin and eosin. The clinical records of the patients were also made. The results are summarized as follows: 1. Squamous metaplasia of the stratified ciliated epithelium was found in 38 out of 60 specimens (63%) of the laryngeal ventricles examined. 2. The metaplasia seemed to be precipitated by smoking or exposure to radiation, along with aging. 3. The incidence and extent of metaplasia of the ventricular mucosa depended on the disease entity which had necessitated total laryngectomy, and the metaplasia was most prominent in cases with the supraglottic type of laryngeal carcinoma. 4. The metaplastic epithelium was occasionally associated with hyperplasia or dysplasia of the epithelium. 5. Microinvasive carcinoma was found in one laryngeal ventricle with severe metaplasia. These findings suggested a possible de novo carcinogenic process in the laryngeal ventricle through squamous metaplasia of the respiratory epithelium. From this observation, the author proposes to call carcinoma of this region of the larynx the ventricular type of laryngeal carcinoma.

Exogenous synapsin I promotes functional maturation of developing neuromuscular synapses

We have investigated the possible role of synapsin I, a nerve terminal-specific protein, in the maturation of neuromuscular synapses in Xenopus cell cultures. Purified synapsin I was loaded into embryonic spinal neurons by injection of the protein into one of the early blastomeres of a Xenopus embryo. At synapses made by synapsin I-loaded neurons, spontaneous synaptic currents occurred with higher frequency and amplitude, and the amplitude exhibited an earlier appearance of a bell-shaped distribution. These characteristics are indicative of more mature quantal secretion. Impulse-evoked synaptic currents also showed a significant increase in amplitude. Using cell manipulation techniques, enhanced transmitter release from synapsin I-loaded neurons was shown to occur at the onset of synaptogenesis, suggesting a presynaptic developmental action of synapsin I prior to synaptic contact. Taken together, these results suggest that endogenous synapsin I may participate in the functional maturation of synapses.

[Changes in excitatory amino acids and N-methyl-D-aspartate receptors in the brain in aged mice]

By means of chromatography and radioligand binding assay, changes of excitatory amino acids (EAA) and N-methyl-D-aspartate(NMDA)receptors in the cerebral cortex of aged mice were investigated. It has been demonstrated that the maximal binding capacity (Bmax) of NMDA-sensitive 3H-L-glutamic acid (3H-L-Glu) in the cerebral cortex of aged mice (14 months) was obviously decreased as compared with that of young mice (2 months), but no significant differences in KD values between young and aged mice were observed. The content of L-Glu in the cerebral cortex of aged mice was reduced 18.7% when compared with that of young mice. However, no change in the content of L-aspartic acid was found. Long-term potentiation (LTP) of synaptic transmissions in the hippocampus is mediated by NMDA receptors. We also confirmed that the slope and amplitude of hippocampal population spikes were significantly lower in aged mice than in young mice after induction of LTP by tetanus (100 Hz, ls), and persistent time of LTP in aged mice was shorter as compared with that in young mice. The results showed that the functions of the central EAA neurotransmitter systems are decreased, and such changes may be related to the decline of learning and memory capacities in the aged.

Regulation of NGF gene expression in CNS glia by cell-cell contact

Nerve growth factor (NGF) gene expression in central nervous system (CNS) glia appears to be associated with active glial growth. To study the underlying molecular mechanisms, we examined the effects of a number of growth-related factors on NGF mRNA expression in glial cultures. Our results suggest that glial membrane interaction, as a consequence of growth, actively inhibits NGF gene expression in CNS glia.