[Long-term evaluation and physical and mental effects of residual tinnitus following treatment of sudden hearing loss]

Objective: To clarify the long-term characteristics of tinnitus following treatment of sudden deafness and its long-term physical and mental effects on patients. Methods: A retrospective analysis was performed on 88 patients (46 males and 42 females; Age from 11 to 89 years) with sudden deafness treated in Department of Otoscope Surgery of Peoples's Libration Army General Hospital in Beijing from April 2020 to January 2021, and the occurrence of tinnitus and treatment effect of all patients were analyzed. Follow-up was conducted for patients with residual tinnitus after treatment for more than 1 year by the investigation and filling in the survey information collection form, Tinnitus Evaluation Questionnaire (TEQ) and Tinnitus Handicap Inventory (THI). Descriptive statistics and SPSS 22.0 software were used for statistical data analysis. Results: In this study, 93.2% (82/88) of patients with sudden deafness were accompanied by tinnitus at the onset, and the proportion of long-term tinnitus after treatment was 90.2% (74/82). After 1 year of treatment for sudden deafness, the improvement of tinnitus was significant in low-frequency sudden deafness compared with those of high-frequency, flat and total deafness sudden deafness (χ2 value was 6.801, 4.568 and 4.038, all P<0.05). In patients with residual tinnitus, 9 (12.2%) patients felt minimal loudness or even no loudness, 34 (46.0%) patients felt slight loudness, 28 (37.8%) patients felt tinnitus was relatively loud, and 3 (4.1%) patients felt tinnitus was loud or noisy. Nine (12.2%) patients's sleep was often affected, 41 (55.4%) patients's sleep was sometimes affected, 9 (12.2%) patients's sleep was rarely affected, 15 (20.3%) patients's sleep was almost not affected. Twenty-eight (37.8%) patients basically completely adapted to tinnitus and 46 (62.2%) patients did not completely adapted to residual tinnitus. Eight (10.8%) patients had no impact on life, 39 (52.7%) patients had slight impact, 22 (29.7%) patients had moderate impact, and the other 5 (6.8%) patients had greater impact. According to tinnitus evaluation questionnaire(TEQ), there were 12 cases (16.2%) of grade Ⅰ, 26 cases (35.1%) of grade Ⅱ, 28 cases (37.8%) of grade Ⅲ, 7 cases (9.5%) of grade Ⅳ and 1 case (1.4%) of grade Ⅴ. According to tinnitus handicap inventory(THI), tinnitus disability was classified into grade Ⅰ, 22 cases (29.7%), grade Ⅱ, 14 cases (18.9%), Grade Ⅲ, 27 cases (36.5%) and grade Ⅳ, 11 cases (14.9%). Conclusion: The rate of residual tinnitus following treatment of sudden deafness is high. Some of the patients can completely adapt residual tinnitus after one year, but some of them will be affected when sleep, work and study. Residual tinnitus can lead to tinnitus disability in different degrees.

[Analysis of differentially expressed microRNA and protein expression profiles carried by exosomes in the plasma of patients with Takayasu's arteritis]

Objective: To detect the microRNAs (miRNAs) and proteins carried by exosomes in the plasma of patients with newly diagnosed Takayasu's arteritis (TAK) and analyze their possible roles in the pathogenesis of TAK. Methods: Ten patients with newly diagnosed TAK from the Department of Rheumatology and Immunology, Peking Union Medical College Hospital were selected during June-November 2020. Five healthy controls were matched with five patients by age and sex. RNA sequencing and protein mass spectrometry were used to detect miRNAs and proteins, respectively, carried by exosomes in the plasma. Differentially expressed miRNAs (DE-miRNAs) and proteins (DEPs) were screened. Thereafter, hierarchical cluster analysis, function, signal pathway, and protein domain enrichment analysis of DE-miRNAs and DEPs were performed. Finally, miRNAs and proteins related to vasculitis and autoimmunity were identified. The possible roles of the miRNAs and proteins in the pathogenesis of TAK were explored. Enumeration data were compared using Fisher's exact probability test or Chi-square test, and a P-value<0.05 was considered significant. Results: Compared with the healthy controls, patients with TAK had 29 DE-miRNAs on their plasma exosomes. Among these DE-miRNAs, miR-101-3p, miR-122-5p, miR-143-3p, miR-185-3p, miR-192-5p, miR-194-5p, miR-19a-3p, miR-19b-3p, miR-20b-5p, miR-21-5p, miR-22-3p, miR-335-5p, miR-34a-5p, miR-3613-5p, miR-548ad-5p, miR-590-3p, and miR-7-5p were upregulated; whereas miR-1249-3p, miR-141-3p, miR-199a-5p, miR-199b-5p, miR-200a-3p, miR-200c-3p, miR-204-5p, miR-29c-5p, miR-335-3p, miR-381-3p, miR-4433b-5p, and miR-584-5p were downregulated. Finally, miR-34a-5p, miR-200c-3p, miR-143-3p, miR-22-3p, and miR-21-5p were identified. Among the 357 DEPs screened, 236 DEPs were upregulated, whereas 121 DEPs were downregulated. Finally, kallikrein B1 (KLKB1), kininogen 1 (KNG1), desmoplakin (DSP) were identified. Conclusion: MiR-34a-5p, miR-200c-3p, miR-143-3p, miR-22-3p, miR-21-5p, KLKB1, KNG1, and DSP carried by exosomes in plasma might participate in the pathogenesis of TAK by regulating vascular physiology, inflammation, autoimmunity, and other processes. They may be biomarkers and therapeutic targets of TAK.

[Application of indocyanine green fluorescence visualization in surgical resection of abdominal wall endometriosis]

Objective: To investigate the feasibility, effectiveness and safety of indocyanine green (ICG) navigation in the surgical resection of abdominal wall endometriosis (AWE). Methods: Seven women undergoing surgery for AWE in First Affiliated Hospital of Sun Yat-sen University (from July 1, 2021 to October 1, 2021) were collected. After exposure of the focus, ICG were used intravenously (0.25 mg/kg) as fluorescent dye for the intraoperative evaluation of AWE vascularization. Resection of the AWE was guided by direct visualization of the focus under standard laparoscopy with a near-infrared (NIR) camera head. Surgical margin around the AWE (3, 6, 9 and 12 point) and the margin under the focus were obtained for postoperative pathological examination of endometriosis. Time from injection to fluorescence visualization, the proportion of fluorescence visualization, time of fully resection of AWE, side effects related to the use of ICG, perioperative complications as well as the pathological result of the surgical margins were recorded. Results: ICG fluorescence of the AWE were seen in 5 patients (5/7). The mean time from injection to fluorescence visualization was (46.7±9.8) s. The mean time of fully resection of AWE was (16.4±7.0) minutes. There were no side effects related to the use of ICG. The rate of class-A wound healing was 7/7. All of the surgical margins were confirmed endometriosis-negative by postoperative pathological examination. Conclusion: ICG fluorescence visualization could conduct accurate resection of AWE, which is clinically safe and effective.

[Case report and diagnosis of Noonan syndrome with multiple lentigines with deafness as its main clinical feature]

Summary Noonan syndrome with multiple lentigines（NSML） is a disorder with syndromic hearing loss. Abnormalities of other systems in NSML have received increasing attention, but hearing loss is rarely concerned. And due to the incomplete phenotype, some patients with NSML maybe missed or maybe confused with other syndromic deafness such as Waardenburg syndrome. Our study will familiarize more otolaryngologists with Leopard syndrome. A 5-year-old boy with bilateral sensorineural hearing loss and numerous symmetrically distributed dark brown macules that had good effect of cochlear implantation was collected in this study. And his father had bilateral sensorineural hearing loss and numerous symmetrically distributed dark brown macules. Waardenburg syndrome was initially diagnosed by clinical phenotype and its molecular etiology was confirmed by gene diagnosis. Waardenburg syndrome-related deafness genes and 131 known deafness genes were not identified by second-generation sequencing. Whole-exon sequencing was performed for 4 individuals in the family and the results were confirmed by Sanger sequencing. This study confirmed the diagnosis by identifying a disease-causing mutation in the PTPN11 gene, which was a heterozygous missense mutation at p. Tyr279Cys（c. 836A>G）. The mutation co-segregated with hearing loss in the family. Our results demonstrated that hearing loss in this family was caused by heterozygous mutations in PTPN11. These cases will familiarize more otolaryngologists with NSML, and they emphasize the importance of considering NSML as a possible cause of hearing problems.

Diurnal variation of CO2, CH4, and N2O emission fluxes continuously monitored in-situ in three environmental habitats in a subtropical estuarine wetland

Wetlands play a crucial role in modulating atmospheric concentrations of greenhouse gases (GHGs) such as carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O). The key factors controlling GHG emission from subtropical estuarine wetlands were investigated in this study, which continuously monitored the uptake/emission of GHGs (CO₂, CH₄, and N₂O) by/from a subtropical estuarine wetland located in the Minjiang estuary in the coastal region of southeastern China. A self-designed floating chamber was used to collect air samples on-site at three environmental habitats (Phragmites australis marsh, mudflats, and river water). The CO₂, CH₄, and N₂O concentrations were then measured using an automated nondispersive infrared analyzer. The magnitudes of the CO₂ and N₂O emission fluxes at the three habitats were ordered as river water>P. australis>mudflats. P. australis emitted GHGs through photosynthesis and respiration processes. Emissions of CH₄ from P. australis and the mudflats were revealed to be slightly higher than those from the river water. The total GHG emission fluxes at the three environmental habitats were quite similar (4.68-4.78gm^-2h^-1). However, when the total carbon dioxide equivalent fluxes (CO₂-e) were considered, the river water was discovered to emit the most CO₂-e compared with P. australis and the mudflats. Based on its potential to increase global warming, N₂O was the main contributor to the total GHG emission, with that emitted from the river water being the most considerable. Tidal water carried onto the marsh had its own GHG content and thus has acted as a source or sink of GHGs. However, water quality had a large effect on GHG emissions from the river water whereas the tidal water height did not. Both high salinity and large amounts of sulfates in the wetlands explicitly inhibited the activity of CH₄-producing bacteria, particularly at nighttime.

Cloning and characterization of the dehydration-responsive element-binding protein 2A gene in Eruca vesicaria subsp sativa

Eruca vesicaria subsp sativa is one of the most tolerant Cruciferae species to drought, and dehydration-responsive element-binding protein 2A (DREB2A) is involved in responses to salinity, heat, and particularly drought. In this study, a gene encoding EvDREB2A was cloned and characterized in E. vesicaria subsp sativa. The full-length EvDREB2A cDNA sequence contained a 388-bp 5'-untranslated region (UTR), a 348-bp 3'-UTR, and a 1002-bp open reading frame that encoded 334 amino acid residues. The theoretical isoelectric point of the EvDREB2A protein was 4.80 and the molecular weight was 37.64 kDa. The genomic sequence of EvDREB2A contained no introns. Analysis using SMART indicated that EvDREB2A contains a conserved AP2 domain, similar to other plant DREBs. Phylogenetic analysis revealed that EvDREB2A and DREB2As from Brassica rapa, Eutrema salsugineum, Arabidopsis thaliana, Arabidopsis lyrata, and Arachis hypogaea formed a small subgroup, which clustered with DREB2Bs from A. lyrata, A. thaliana, Camelina sativa, and B. rapa to form a larger subgroup. EvDREB2A is most closely related to B. rapa DREB2A, followed by DREB2As from E. salsugineum, A. thaliana, A. hypogaea, and A. lyrata. A quantitative real-time polymerase chain reaction indicated that EvDREB2A expression was highest in the leaves, followed by the roots and hypocotyls, and was lowest in the flower buds. EvDREB2A could be used to improve drought tolerance in crops.

Effect of nitrate enrichment and diatoms on the bioavailability of Fe(III) oxyhydroxide colloids in seawater

The photoconversion of colloidal iron oxyhydroxides was a significant source of bioavailable iron in coastal systems. Diatoms dominate phytoplankton communities in coastal and upwelling regions. Diatoms are often exposed to eutrophication. We investigated the effects of different species of diatom, cell density, illumination period, and nitrate additions on the bioavailability of Fe(III) oxy-hydroxide colloids in seawaters. With the increase of illumination period from 1 to 4 h, the ratios of concentrations of total dissolved Fe (DFe) to colloidal iron oxyhydroxides and Fe(II) to DFe increased up to 24.3% and 23.9% for seawater without coastal diatoms, 45.6% and 30.2% for Skeletonema costatum, 44.3% and 29.7% for Thalassiosira weissflogii, respectively. The photochemical activity of coastal diatoms themselves (excluding the dissolved organic matter secreted by algae) on the species transformation of iron in seawater (including the light-induced dissolution of Fe(III) oxyhydroxide colloids and the photo-reduction of Fe(III) into Fe(II)) was confirmed for the first time. There was no significant difference of the ability of S. costatum and Thalassiosira weissflogii on the photoconversion of colloidal iron oxyhydroxides. The photoproduction of dissolved Fe(II) and DFe in the seawater with or without diatoms could be depressed by the nitrate addition.

Effect of excessive CO2 on physiological functions in coastal diatom

Rising dissolution of anthropogenic CO₂ in seawater may directly/indirectly cause ocean acidification and desalination. However, little is known about coastal physiological functions sensitivity to these processes. Here we show some links between ocean acidification/desalination and physiological functions in Thalassiosira weissflogii. Cell density (CD), protein, chlorophyll a (Chl a), malonaldehyde (MDA), superoxide dismutase (SOD), and carbonic anhydrase (CAs) were determined for the assessment of algal biomass, nutritional value, photosynthesis and respiration, lipid peroxidation, antioxidant capacity, and carbon sequestration ability. The influence of pH on the algal Chl a and MDA were extremely significant (P < 0.01). Salinity (S) on cell density and acidity (pH) on protein was significant (0.01 < P < 0.05). Additionally, a significant negative-correlation was observed between cell density and CAs. CAs and SOD had negatively correlations with CD, Chl a, protein, and MDA under pH or S influence, but positive correlation between themselves. Coastal physiological functions were affected by increasing order was acidification < acidification + desalination < desalination for Chl a and protein, desalination < acidification + desalination < acidification for SOD and CAs. Thus, the ongoing excessive CO₂-driven ocean acidification and desalination should be of high attention when assessing the risks of climate change on coastal phytoplankton.

Cloning and characterization of ADP-glucose pyrophosphorylase small subunit gene in Cyperus esculentus (yellow nutsedge)

ADP-glucose pyrophosphorylase (ADPGlcPPase) controls the first committed step of starch synthesis by catalyzing the biosynthesis of ADP-glucose from glucose-phosphate and ATP. It is a tetrameric protein consisting of two small and two large subunits. The small subunits have a catalytic function, while the large subunits regulate the enzyme activity. Cyperus esculentus (yellow nutsedge) is a perennial C4 plant grown from rhizomes and tubers. Previous studies on yellow nutsedge have mostly focused on the morphology and cultivation of tubers, their application in food, and biochemical analyses of the tubers. In this study, the gene encoding the ADPGlcPPase small subunit (CeAGPS) in yellow nutsedge was cloned and characterized. The full-length CeAGPS cDNA sequence contained an 81-bp 5'-untranslated region (UTR), a 188-bp 3'-UTR, and a 1539-bp open reading frame encoding 512-amino acid residues. The genomic sequence of CeAGPS comprises a nine exon-eight intron structure similar to the previously reported cotton and Arabidopsis thaliana AGPS genes. The deduced translation product of the CeAGPS gene contained a well-conserved catalytic domain and regulatory elements typical of plant AGPS. Reverse transcriptase polymerase chain reaction amplification of the target gene in various plant parts using gene-specific primers indicated that the expression of CeAGPS was most abundant in the tuber, and relatively lower in nutsedge roots.

Production and genetic characterization of interspecific hybrids among Crambe abyssinica, Crambe hispanica and Crambe kralikii

In this paper, interspecific crosses among Crambe abyssinica, Crambe hispanica, and Crambe kralikii were reported. In the C. hispanica x C. abyssinica (H x A) cross, 118 F1 hybrids were produced without embryo rescue, while 5 F1 hybrids were obtained with embryo rescue, when C. hispanica was used as the female parent. In the reciprocal cross (A x H), 232 hybrids were obtained without embryo rescue. From more than 1000 C. kralikii flowers pollinated with pollen grains of C. abyssinica (K x A), only 2 F1 hybrids were obtained with embryo rescue, whereas the reciprocal cross produced no hybrids, even with embryo rescue. The hybrids were confirmed at the morphological, cytological, and molecular levels. In the combinations of A x H and H x A, many BC1 hybrids were obtained without embryo rescue. In contrast, in the K x A cross, only 7 BC1 plants were obtained with embryo rescue, while no seed set was achieved under self-pollination or in backcrosses without embryo rescue. In the H x A F1 hybrids, the pollen stainability was 65.4-86.0%, with an average of 76.9%. In comparison, the pollen viability of hybrids in the reciprocal cross (A x H) ranged from 66.2 to 81.1%, with an average of 75.4%. Fertile pollen grains were not found in the K x A F1 hybrids. All F1 hybrids of the 3 crosses (H x A, A x H, and K x A) had the expected 2n = 75 chromosomes. AFLP analyses indicated that all F1 hybrids and their progenies had typical bands of the parents. These hybrids and progenies are anticipated to be valuable for future C. abyssinica improvement in breeding programs.

[Dynamic changes of phytoplankton's community structure in Beixi of Jiulongjiang River, Fujian Province of East China and related affecting factors]

An investigation was conducted on the phytoplankton' s community composition, abundance, and their relations with environmental factors in Beixi of Jiulongjiang River, Fujian Province in February (dry season), May (wet season), and October (normal season), 2011. A total of 107 phytoplankton species were identified, belonging to 64 genera and 7 phyla. The dominant species changed with seasons. Campylomonas marssoni and Cyclotella meneghiniana dominated in dry season, Scenedesmus quadricauda and Crucigenia tetrapedia dominated in wet season, and Merismopedia tenuissima dominated in normal season. The phytoplankton's abundance was the highest in dry season (averaged 154.77 x 10(4) cells x L(-1)), followed by in normal season (76.40 x 10(4) cells x L(-1)), and in wet season (45.40 x 10(4) cells x L(-1)). The abundance in dry and normal seasons was significantly positively correlated with water ammonium nitrogen concentration (P<0.05) , while that in wet season was significantly positively correlated with water temperature (P<0.01). Canonical correspondence analysis (CCA) showed that water temperature was the most important factor affecting the phytoplankton's community structure, and dissolved phosphorous concentration also played important role for the community structure. The CCA ordination plots could well display the phytoplankton' s community structure and its relationships with environmental factors.

A mouse model of autosomal recessive polycystic kidney disease with biliary duct and proximal tubule dilatation

Autosomal recessive polycystic kidney disease (ARPKD) is caused by mutations in the polycystic kidney and hepatic disease (PKHD1) gene encoding the protein fibrocystin/polyductin. The aim of our study was to produce a mouse model of ARPKD in which there was no functional fibrocystin/polyductin to study the pathophysiology of cystic and fibrocystic disease in renal and non-renal tissues. Exon 2 of the gene was deleted and replaced with a neomycin resistance cassette flanked by loxP sites, which could be subsequently removed by Cre-lox recombinase. Homozygous Pkhd1(del2/del2) mice were viable, fertile and exhibited hepatic, pancreatic, and renal abnormalities. The biliary phenotype displayed progressive bile duct dilatation, resulting in grossly cystic and fibrotic livers in all animals. The primary cilia in the bile ducts of these mutant mice had structural abnormalities and were significantly shorter than those of wild-type (WT) animals. The Pkhd1(del2/del2) mice often developed pancreatic cysts and some exhibited gross pancreatic enlargement. In the kidneys of affected female mice, there was tubular dilatation of the S3 segment of the proximal tubule (PT) starting at about 9 months of age, whereas male mice had normal kidneys up to 18 months of age. Inbreeding the mutation onto BALBc/J or C57BL/6J background mice resulted in females developing PT dilatation by 3 months of age. These inbred mice will be useful resources for studying the mechanisms underlying the pathogenesis of ARPKD.

Circular F-actin bundles and a G-actin gradient in pollen and pollen tubes of Lilium davidii

The distribution of and relationship between F-actin and G-actin were investigated in pollen grains and pollen tubes of Lilium davidii Duch. using a confocal laser scanning microscope after fluorescence and immunofluorescence labeling. Circular F-actin bundles were found to be the main form of microfilament cytoskeleton in pollen grains and pollen tubes. Consistent with cytoplasmic streaming in pollen tubes, there were no obvious F-actin bundles in the 10- to 20-microm tip region of long pollen tubes, only a few short F-actin fragments. Labeling with fluorescein isothiocyanate (FITC)-DNase I at first established the presence of a tip-focused gradient of intracellular G-actin concentration at the extreme apex of the tube, the concentration of G-actin being about twice as high in the 10- to 20-microm region of the tip as in other regions of the pollen tube. We also found that the distribution of G-actin was related negatively to that of the F-actin in pollen tubes of L. davidii. Caffeine treatment caused the G-actin tip-focused gradient to disappear, and F-actin to extend into the pollen tube tip. Based on these results, we speculate that the circular F-actin bundles may be the track for bidirectional cytoplasmic streaming in pollen tubes, and that in the pollen tube tip most of the F-actin is depolymerized into G-actin, leading to the absence of F-actin bundles in this region.

[Production and cytogenetics of intergeneric hybrids between Ogura CMS Brassica campestris var. purpuraria and Raphanus sativus]

Crosses between Ogura CMS Brassica campestris var. purpuraria (AA, 2n = 20) and Raphanus sativus (RR, 2n = 18) were made and many intergeneric hybrids were produced. The F1 seedlings did not show chlorosis at low temperature. When red Raphanus sativus varieties were used as male parent, the leaf petiole and leaf vein of F1 plants were purple, and when white Raphanus sativus varieties were used as male parent, the leaf petiole and leaf vein of F1 plants were not purple. All the F1 plants had white flowers and normal honey glands. Male gametes of the F1 were highly sterile and female gametes of the F1 were partly fertile. Cytological studies indicated that chromosome number of the F1 was 2n = 19 as expected, the mean chromosome pairing pattern was 15.53 I + 1.34 II + 0.25 III + 0.01 IV. Most chromosomes exsistet as univalents, but there also exsisted some bivalents, trivalents and even tetravalents, suggesting that chromosome set A was partly homologous with chromosome set R.

Symplastic communication between the central cell and the egg apparatus cells in the embryo sac of Torenia fournieri Lind. before and during fertilization

Various membrane-impermeable, water-soluble fluorescent tracers with different molecular weights were microinjected into the central cell of the embryo sac of Torenia fournieri Lind. before and during fertilization. Before anthesis, there was high symplastic permeability between the central cell and the egg apparatus cells. In this stage, fluorescent tracers up to 10 kDa could pass from the central cell into the egg apparatus cells, whereas those with larger molecular weight remained in the central cell. As the embryo sac matured, symplastic permeability decreased such that 2 d after anthesis only tracers less than 3 kDa could spread from the central cell into the egg cell. There appeared to be no symplastic permeability between the primary endosperm and zygote after fertilization, since tracers as small as 521 Da could not pass into the zygote in about half of the microinjected embryo sacs. This is the first report of a change in cell-to-cell communication among the cells of the female germ unit before and after fertilization.

[Effects of the interaction between histone and hAMFR gene promoter on the transcription activity in vitro]

The effects of interaction between histones and human autocrine motility factor receptor (hAMFR) gene promoter on the transcription activity in vitro was investigated by using histones purified from chicken erythrocytes, HeLa cell nuclear extracts and heat-treated supernatants of Xenopus eggs. The results showed that the competitive binding of histones and transcription factors at the promoter of hAMFR gene was very important to the transcription in vitro. If a pre-initiation complex was formed with HeLa cell nuclear extracts on the promoter prior to nucleosome assembly, it would prevent nucleosome-mediated transcription repression. When the nucleosome was assembled on the promoter in advance, the transcription activity could be repressed. When histones and HeLa cell nuclear extracts were mixed in the reaction simultaneously, the transcription activity would depend on the relative amount of histones to that of HeLa cell nuclear extracts.

[Binding and interaction of histones and transcription factors on the promoter of hAMFR gene]

In this study, histone H1, core histones H2A-H2B and H3-H4 were purified from chicken erythrocytes by hydroxylapatile chromatography. The nuclear extract was prepared from HeLa cells. We investigated the binding and interaction of histones and transcription factors on the upstream sequence of human autocrine motility factor receptor (hAMFR) gene by gel shift mobility assay. We found that the binding of H1 on the promoter sequence of hAMFR gene was relatively stable. We propose that H1 plays an important role in stablizing chromatosome. We also found that histones and HeLa cell extract could form a ternary complex with the DNA template.

Isolation of a gene encoding Arabidopsis membrane-associated acyl-CoA binding protein and immunolocalization of its gene product

Until recently, only cytosolic acyl-CoA binding proteins (ACBPs) have been characterized. The isolation of an Arabidopsis thaliana cDNA encoding a novel membrane-associated ACBP that accumulates in developing seeds, designated ACBP1, has provided evidence for the existence of membrane-associated forms of ACBPs (Chye, 1998, Plant Mol. Biol. 38, 827-838). We now report on the isolation of its corresponding gene from an A. thaliana Columbia genomic library using the ACBP1 cDNA as a hybridization probe. Nucleotide sequence analysis of Arabidopsis ACBP1 showed that its promoter lacks a TATA box, resembling the promoters of rat, Drosophila and human genes encoding cytosolic ACBP and suggesting that it is a housekeeping gene. We show by Western blot analysis that ACBP1 expression in developing seeds coincides with lipid deposition and that homologues of membrane-associated ACBP1 exist in other plants. Using light microscopy, we show that ACBP1 is strongly expressed in the embryo at the cotyledons, hypocotyl, procambium of the axis and in most peripheral cells of the cotyledons and hypocotyl. Immunogold labelling localized ACBP1 to vesicles, to the plasma membrane especially at epidermal cells of heart, torpedo and cotyledonary stage embryos, and to the cell wall of the outer integument cells at the seed coat. Our results suggest that ACBP1 is involved in intermembrane lipid transport from the ER via vesicles to the plasma membrane where it could maintain a membrane-associated acyl pool; its immunolocalization to the cell wall of outer integument cells at the seed coat suggests a role in cuticle and cutin formation.

Three-dimensional organization and dynamic changes of the actin cytoskeleton in embryo sacs of Zea mays and Torenia fournieri

Actin organization was observed in m-maleimidobenzoic acid N-hydroxysuccinimide ester(MBS)-treated maize embryo sacs by confocal laser scanning microscopy. The results revealed that dynamic changes of actin occur not only in the degenerating synergid, but also in the egg during fertilization. The actin filaments distribute randomly in the chalazal part of the synergid before fertilization; they later become organized into numerous aggregates in the chalazal end after pollination. The accumulation of actin at this region is intensified after the pollen tube discharges its contents. Concurrently, actin patches have also been found in the cytoplasm of the egg cell and later they accumulate in the cortical region. To compare with MBS-treated maize embryo sacs, we have performed phalloidin microinjection to label the actin cytoskeleton in living embryo sacs of Torenia fournieri. The results have extended the previous observations on the three-dimensional organization of the actin arrays in the cells of the female germ unit and confirm the occurrence of the actin coronas in the embryo sac during fertilization. We have found that there is an actin cap occurring near the filiform apparatus after anthesis. In addition, phalloidin microinjection into the Torenia embryo sac has proved the presence of intercellular actin between the cells of the female germ unit and thus confirms the occurrence of the actin coronas in the embryo sac during fertilization. Moreover, actin dynamic changes also take place in the egg and the central cell, accomplished with the interaction between the male and female gametes. The actin filaments initially organize into a distinct actin network in the cortex of the central cell after anthesis; they become fragmented in the micropylar end of the cell after pollination. Similar to maize, actin patches have also been observed in the egg cortex after pollination. This is the first report of actin dynamics in the living embryo sac. The results suggest that the actin cytoskeleton may play an essential role in the reception of the pollen tube, migration of the male gametes, and even gametic fusion.

Cytoskeletal organisation and modification during pollen tube arrival, gamete delivery and fertilisation in Plumbago zeylanica

The cytoskeletal organisation of the isolated embryo sac and egg cells of Plumbago zeylanica was examined before, during and after pollen tube penetration into the embryo sac to determine the potential involvement of microtubules and actin filaments in fertilisation. Material was singly and triply stained using Hoechst 33258 to localise DNA, fluorescein isothiocyanate (FITC)-labelled anti-alpha-tubulin to detect microtubules and rhodamine-phalloidin to visualise F-actin. Microtubules in the unfertilised egg cell are longitudinally aligned in the micropylar and mid-lateral areas, aggregating into bundles near the filiform apparatus. In the perinuclear cytoplasm of the egg cell, microtubules become more or less randomly aligned. F-actin bundles form a longitudinally aligned mesh in the chalazal cytoplasm of the egg cell. In the central cell, microtubules and F-actin are distributed along transvacuolar strands and are also evident in the perinuclear region and at the periphery of the cell. During pollen tube penetration, sparse microtubule bundles near the pathway of the pollen tube may form an apparent microtubular 'conduit' surrounding the male gametes at the delivery site. Actin aggregates become organised near the pathway of the pollen tube and at the delivery site of the sperm cells. Subsequently, actin aggregates form a 'corona' structure in the intercellular region between the egg and central cell where gametic fusion occurs. The corona may have a role in maintaining the close proximity of the egg and central cell and helping the two sperm cells move and bind to their target cells. The cytoskeleton may also be involved in causing the two nuclei of the egg and central cell to approach one another at the site of gametic fusion and transporting the two sperm nuclei into alignment with their respective female nucleus. The cytoskeleton is reorganised during early embryogenesis.

Isolation of Fixed and Viable Eggs, Central Cells, and Embryo Sacs from Ovules of Plumbago zeylanica

Three alternative protocols for light microscopy, electron microscopy, and biochemical characterization of isolated megagametophytic tissues are described employing enzymic maceration and microdissection of living and fixed ovular tissue of Plumbago zeylanica. Morphologically well preserved megagametophytes are obtained using fixed ovules in two different regimes (nearly 40 and 60% yield, respectively). Fluorescein diacetate-positive megagametophytic cells are recovered in nearly 20% of unfixed ovules using the third regime.