Determination of nitrobenzene potential genotoxic impurities in nifedipine with GC-MS.

There is an increasing scientific interest in the detection of genotoxic impurities (GTIs), with nitrobenzene compounds being considered potential genotoxic impurities due to their structural alerts, which demonstrates a threat to drug safety for patient. While current reports on the detection of nifedipine impurity primarily focus on general impurities in nifedipine. In this study, an effective and simple gas chromatography-mass spectrometry (GC-MS) method was established and verified for the separation and quantification of 2-nitrotoluene, 2-nitrobenzyl alcohol, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde, and 2-nitrobenzyl bromide in nifedipine, which have not been previously reported. The validation of this GC-MS method was conducted following the International Conference of Harmonization (ICH) guidelines, exhibiting good linearity within the range of 2-40 µg/g and accuracy between 84.6 % and 107.8 %, the RSD% of intra-day and inter-day precision was in the range of 1.77-4.55 %, stability and robustness also met acceptance criteria. This method filled the gap in detection method for nitrobenzene compounds in nifedipine, offering a novel method and technical support for nifedipine quality control.

Study of the impurity profile of photodegradation in lomefloxacin hydrochloride ear drops using liquid chromatography combined with ion trap/time-of-flight mass spectrometry.

RATIONALE: Lomefloxacin hydrochloride ear drops are highly unstable to light and prone to produce photodegradation impurities. These impurities might be related to the phototoxicity of lomefloxacin, which could seriously threaten the health of patients. In this article, the photodegradation impurity profile in lomefloxacin hydrochloride ear drops was studied for further improvement of quality control of the drug. METHODS: By studying the chromatographic behavior of photodegradation impurities, the photodegradation impurities in lomefloxacin hydrochloride ear drops were separated and detected effectively. Liquid chromatography combined with ion trap/time-of-flight mass spectrometry was applied to characterize the structures of the photodegradation impurities in lomefloxacin hydrochloride ear drops. RESULTS: The structures of 17 impurities in lomefloxacin hydrochloride ear drops were elucidated based on high-resolution MSn data in positive ion mode, 12 of them being unknown impurities. CONCLUSIONS: The structural characteristics and fragmentation patterns of the photodegradation impurities were also studied. The study of the photodegradation impurity profile in lomefloxacin hydrochloride ear drops provides a scientific basis for quality control of these ear drops and ensures the safety of drug use by the public.

Optimised Agrobacterium-Mediated Transformation and Application of Developmental Regulators Improve Regeneration Efficiency in Melons.

Melon (Cucumis melo L.) is a protected crop in China with high economic value. Agrobacterium-mediated genetic transformation is a powerful tool to improve agronomic traits and obtain elite germplasm. However, current transformation protocols in melons are inefficient and highly genotype-dependent. To improve transformation in melon, we tested different infiltration methods for Agrobacterium-mediated transformation. Among these methods, micro-brushing and sonication for 20 s, followed by vacuum infiltration at -1.0 kPa for 90 s, resulted in the strongest green fluorescent protein signal and increased the proportion of infected explants. We transformed melon with developmental regulatory genes AtGRF5, AtPLT5, AtBBM, AtWUS, AtWOX5, and AtWIND1 from Arabidopsis and estimated regeneration frequencies as the number of regenerating shoots/total number of inoculated explants in the selection medium. The overexpression of AtGRF5 and AtPLT5 in melon resulted in transformation efficiencies of 42.3% and 33% in ZHF and 45.6% and 32.9% in Z12, respectively, which were significantly higher than those of the control. AtGRF5 and AtPLT5 expression cassettes were added to CRISPR/Cas9 genome-editing vectors to obtain transgenic phytoene desaturase CmPDS knockout mutants. Using AtGRF5 or AtPLT5, multi-allelic mutations were observed at CmPDS target sites in recalcitrant melon genotypes. This strategy enables genotype-flexible transformation and promotes precise genome modification technologies in melons.

Description of Sarcocystis platyrhynchosi n. sp. (Apicomplexa: Sarcocystidae) from domestic ducks Anas platyrhynchos (Anseriformes: Anatidae) in China.

BACKGROUND: Limited data are currently available on protozoan parasites of the genus Sarcocystis that infect their avian hosts within the order Anseriformes (waterfowl). To date, no Sarcocystis species has been recorded in ducks in China. METHODS: Leg muscles were sampled from 26 domestic ducks (Anas platyrhynchos) in China in 2021. Morphological characteristics of sarcocysts detected in the muscle tissue were described using light microscopy (LM) and transmission electron microscopy (TEM). Genomic DNA was extracted from single sarcocysts obtained from different ducks, and three genetic markers, 18S ribosomal DNA (18S rDNA), 28S ribosomal DNA (28S rDNA) and mitochondrial (mt) cytochrome oxidase subunit 1 (cox1), were amplified and cloned for sequence analyses. RESULTS: Sarcocysts were observed by LM in only three of the 28 samples (10.7%). These sarcocysts had a thick cyst wall with numerous brush-like villar protrusions (vps) of 3.8-4.3 µm in length (n = 30) on the cyst surface. TEM observation showed that the sarcocysts had lanceolated vps. Each vps narrowed in the stalk and contained a bundle of microtubules that extended into the ground substance. Comparisons of the new sequences with those deposited in GenBank showed that the most similar sequences were those of Sarcocystis halieti in the great cormorant Phalacrocorax carbo and European starling Sturnus vulgaris, and Sarcocystis calchasi in the domestic pigeon (Columba livia) at the 18S rDNA (99.1% identity); Sarcocystis wenzeli from the domestic chicken Gallus gallus at the 28S rDNA (95.9-96.0% identity); and Sarcocystis speeri from the opossum at the mtcox1 (98.2% identity). The new 18S rDNA, 28S rDNA and mitochondrial cox1 sequences shared up to 99.0%, 95.6% and 97.7% identity, respectively, with those of Sarcocystis spp. obtained from Anseriformes avian hosts. Phylogenetic analysis inferred from the sequences of the three genetic markers placed the organism within a group of Sarcocystis spp. obtained from avian or carnivorous intermediate hosts and avian, marsupial or carnivorous definitive hosts. Based on the morphological observation and molecular analyses, the organism found in the Chinese domestic ducks was regarded as a new species and named Sarcocystis platyrhynchosi n. sp. CONCLUSIONS: Based on morphology and sequence analyses, the microcysts diagnosed in the domestic ducks examined in this study were named as a new species. This is the first record of Sarcocystis spp. from waterfowl in China. Sarcocysts of similar morphology occur frequently in different Anseriformes birds, and the relationships among these species need to be further clarified in future studies using more molecular markers.

Determination of elemental impurities in lomefloxacin hydrochloride ear drops by inductively coupled plasma-mass spectrometry using oxygen reaction mode and study of their catalytic effect on photodegradation reaction.

RATIONALE: This study developed a method for the simultaneous determination of 12 element impurities in lomefloxacin hydrochloride ear drops using inductively coupled plasma-mass spectrometry (ICP-MS) in accordance with the requirements of the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use Q3D. However, this product contains high concentrations of organic compounds such as glycerol and ethanol, and soluble carbon interference exists when it is determined by direct injection method. Therefore, we applied ICP-MS using oxygen reaction mode to reduce the effect of high organic matter on plasma body. The catalytic effect of trace metal ions on the photodegradation of lomefloxacin hydrochloride was also investigated. METHODS: The sample was dissolved, diluted, and directly determined by direct injection using oxygen reaction mode of ICP-MS with 45 Sc, 73 Ge, and 115 In as internal standards. Direct injection using oxygen reaction mode was equipped with argon-oxygen mixer. To investigate the catalytic effect of metal ions on photodegradation, a series of combinations of lomefloxacin hydrochloride mixed with different metal ions were designed. After being irradiated under ultraviolet light for 10 days, the photodegraded impurities in combinations were determined using high-performance liquid chromatography. RESULTS: The linear relationships in the corresponding concentration range for 12 element impurities were good (r > 0.9993). Limits of detection were between 0.002 and 1.294 ng ml-1 . The average recoveries were 93.7%-108.2%, and the precision relative standard deviation was 0.04%-0.55% (n = 6). The experimental results showed that metal ions had a certain catalytic effect on photodegradation of lomefloxacin when EDTA, Mg2+ , and Cu2+ coexisted. CONCLUSIONS: ICP-MS using oxygen reaction mode is suitable for the direct determination of the sample rich in organic matter without digestion and can effectively eliminate the interference of high organic matter in this product. The established method was rapid, sensitive, and accurate and can be used for the quality control of elemental impurities in lomefloxacin hydrochloride ear drops.

Infection of the Asian gray shrew Crocidura attenuata (Insectivora: Soricidae) with Sarcocystis attenuati n. sp. (Apicomplexa: Sarcocystidae) in China.

BACKGROUND: Data on the genus Sarcocystis in insectivores are limited. The Asian gray shrew Crocidura attenuata is one of the most common species of the insectivore family Soricidae in South Asia and Southeast Asia. To our knowledge, species of Sarcocystis have never been recorded previously in this host. METHODS: Tissues were obtained from 42 Asian gray shrews caught in 2017 and 2018 in China. Sarcocysts were observed using light microscopy (LM) and transmission electron microscopy (TEM). To describe the parasite life cycle, muscle tissues of the host infected with sarcocysts were force-fed to two beauty rat snakes Elaphe taeniura. Individual sarcocysts from different Asian gray shrews, and oocysts/sporocysts isolated from the small intestines and feces of the experimental snakes, were selected for DNA extraction, and seven genetic markers, namely, two nuclear loci [18S ribosomal DNA (18S rDNA) and internal transcribed spacer region 1 (ITS1)], three mitochondrial genes [cytochrome oxidase subunit 1 (cox1), cox3 and cytochrome b], and two apicoplast genes (RNA polymerase beta subunit and caseinolytic protease C), were amplified, sequenced and analyzed. RESULTS: Sarcocysts were found in 17 of the 42 (40.5%) Asian gray shrews. Under LM, the microscopic sarcocysts showed saw- or tooth-like protrusions measuring 3.3-4.5 µm. Ultrastructurally, the sarcocyst wall contained numerous lancet- or leaf-like villous protrusions, similar to those described for type 9h of the common cyst wall classification. The experimental beauty rat snakes shed oocysts/sporocysts measuring 11.9-16.7 × 9.2-10.6 µm with a prepatent period of 10-11 days. Comparison of the newly obtained sequences with those previously deposited in GenBank revealed that those of 18S rDNA and cox1 were most similar to those of Sarcocystis scandentiborneensis recorded in the tree shrews Tupaia minor and Tupaia tana (i.e., 97.6-98.3% and 100% identity, respectively). Phylogenetic analysis based on 18S rDNA or ITS1 sequences placed this parasite close to Sarcocystis spp. that utilize small animals as intermediate hosts and snakes as the known or presumed definitive host. On the basis of morphological and molecular characteristics and host specificity, the parasite was proposed as a new species, named Sarcocystis attenuati. CONCLUSIONS: Sarcocysts were recorded in Asian gray shrews, to our knowledge for the first time. Based on morphological and molecular characterization, a new species of parasite is proposed: Sarcocystis attenuati. According to the LM and TEM results, S. attenuati sarcocysts are distinct from those of Sarcocystis spp. in other insectivores and those of S. scandentiborneensis in tree shrews. The 18S rDNA or cox1 sequences of Sarcocystis attenuati shared high similarity with those of Sarcocystis scandentiborneensis, Sarcocystis zuoi, Sarcocystis cf. zuoi in the Malayan field rat, and Sarcocystis sp. in the greater white-toothed shrew. Therefore, we suggest that more research on the relationships of these closely related taxa should be undertaken in the future.

Morphological and molecular characterization of Sarcocystis wenzeli in chickens (Gallus gallus) in China.

BACKGROUND: There has been considerable confusion concerning the number and classification of Sarcocystis spp. in chickens. Scarce nucleotide data of Sarcocystis spp. from chickens are provided in GenBank. The study aimed to investigate the morphological and molecular characteristics of Sarcocystis spp. found in chickens in China. METHODS: Tissues from 33 chickens were collected in 2019. Sarcocysts were observed using light (LM) and transmission electron microscopy (TEM). Individual sarcocysts from different chickens were selected for DNA extraction, and five loci, 18S rDNA, 28S rDNA, ITS1 region, the mitochondrial cox1 gene and the apicoplastic rpoB gene, were amplified from each sarcocyst, sequenced and analyzed. RESULTS: Only S. wenzeli was found in 14 of 33 (42.4%) chickens. Under LM, the sarcocysts were microscopic and exhibited palisade-like villar protrusions measuring 1.5-2.8 µm. Ultrastructurally, the sarcocyst wall contained numerous stubby hill-like villar protrusions. The protrusions included scattered microtubules, which extended from the tips of the protrusions into the ground substance. The five loci were successfully sequenced and the sequences deposited in GenBank. At 18S rDNA, ITS1 and cox1, the most similar sequences in GenBank were those of Sarcocystis sp. obtained from the brains of chickens, i.e. 99.9-100%, 98.1-98.5% and 99.3% identity, respectively. The five loci (18S rDNA, 28S rDNA, ITS1, cox1 and rpoB) showed different levels of interspecific sequence similarity with other closely related species of Sarcocystis (e.g. 99.8%, 99.0-99.2%, 89.3-89.7%, 98.5%, and 97.5%, respectively, with S. anasi). Phylogenetic analysis based on four of the loci (18S rDNA, cox1, rpoB and ITS1) revealed that S. wenzeli formed an independent clade with Sarcocystis spp. that utilize geese or ducks as intermediate hosts and canines as the known or presumed definitive host. CONCLUSIONS: To our knowledge, the sequences of 28S rDNA and rpoB reported here constitute the first records of genetic markers of Sarcocystis spp. in chickens. Based on molecular analysis, S. wenzeli might be responsible for the neurological disease in chickens, and ITS1 and rpoB are more suitable for discriminating it from closely related Sarcocystis spp. Phylogenetic analysis revealed that S. wenzeli presents a close relationship with Sarcocystis spp. in geese or ducks.

Fast Heat Transport Inside Lithium-Sulfur Batteries Promotes Their Safety and Electrochemical Performance.

Lithium-sulfur batteries are paid much attention owing to their high specific capacity and energy density. However, their practical applications are impeded by poor electrochemical performance due to the dissolved polysulfides. The concentration of soluble polysulfides has a linear relationship with the internal heat generation. The issue of heat transport inside lithium-sulfur batteries is often overlooked. Here, we designed a functional separator that not only had a high thermal conductivity of 0.65 W m-1 K-1 but also alleviated the diffusion of dissolved active materials to the lithium anode, improving the electrochemical performance and safety issue. Lithium-sulfur batteries with the functional separator have a specific capacity of 1,126.4 mAh g-1 at 0.2 C, and the specific capacity can be remained up to 893.5 mAh g-1 after 100 cycles. Pouch Cells with high sulfur loading also showed a good electrochemical performance under a lean electrolyte condition of electrolyte/sulfur (E/S) = 3 µL mg-1.

Redescription and molecular characterization of sarcocysts of Sarcocystis cymruensis from Norway rats (Rattus norvegicus) and Sarcocystis ratti from black rats (R. rattus) in China.

In the present study, sarcocysts of Sarcocystis cymruensis were found in four of 42 (9.5%) Norway rats and those of S. ratti were observed in six of 60 (10%) black rats in China. With light microscopy, the sarcocysts of the two parasites were microscopic, and had smooth, thin cyst walls (≤ 1 µm). Ultrastructurally, the sarcocysts of S. cymruensis had small, osmiophilic, bleb-like protrusions, similar to type 1c; those of S. ratti had a cyst wall with regular, short, conical protrusions, similar to type 1 g. Three loci, i.e., 18S rDNA, the mitochondrial cox1 gene (Cox1), and the mitochondrial Cytb gene (Cytb), of the two parasites were sequenced and analyzed, and the Cytb sequences of the two parasites constituted the first records of this marker in GenBank. A comparison of the newly obtained sequences of the three loci between the two parasites revealed that the interspecific similarities of 18S rDNA, Cox1, and Cytb were 96.4-97.2%, 96.5%, and 93.7%, respectively. Therefore, the two species could be better discriminated with Cytb than with 18S rDNA and Cox1. Phylogenetic analysis based on 18S rDNA sequences and Cox1 sequences indicated that the two parasites had a close relationship with Sarcocystis in nonruminant animals, especially birds and canids.

Efficient Characterization of Tetraploid Watermelon.

Watermelon (Citrullus lanatus (Thunb.) Matsum. &Nakai) is an economic crop, which is widely cultivated around the world. The ploidy study of watermelon has an important role in field breeding and production, therefore, timely and convenient ploidy detection is necessary to accelerate its application. Traditionally, the ploidy of watermelon was determined by a series of time-consuming, expensive, and less efficient methods. In this study, we developed a more efficient method to simplify and accelerate the polyploidy identification in watermelons. We first confirmed the ploidy of watermelon by traditional tetraploid morphological features and well-established flow cytometry (FCM). Then we developed a reliable real-time quantitative PCR (qPCR) technique by quantifying the highly conserved 5S rDNA sequence and its copy numbers. This technique requires less sample collection and has comparable accuracy to FCM, it accelerates the analysis process and provides a new method for the identification of polyploidy of watermelon.

Scalable Approach to Construct Self-Assembled Graphene-Based Films with An Ordered Structure for Thermal Management.

Large-area bulk oxidized cellulose nanocrystal (OCNC)/graphene nanocomposites with highly oriented structures were produced through a straightforward, cost-effective large-scale evaporation-induced self-assembly process followed by thermal curing. Well-aligned nano-sized graphene layers were evident and separated by the OCNC planar layers, which facilitate highly interconnected and continuous thermal transport parallel to the alignment. Hence, the laminated graphene-based nanocomposites possess an excellent in-plane thermal conductivity of 25.66 W/m K and a thermal conductivity enhancement (η) of 7235% with only a 4.1 vol % graphene loading. This value is the highest recorded among all laminated composite films with <70 wt % filler content reported to date. Using this design strategy, other large-area aligned composites with other functional nanomaterials, already in large-scale production, can be made for use in a wide range of applications.

Genome-wide identification of SAUR genes in watermelon (Citrullus lanatus).

The early auxin responsive SAUR family is an important gene family in auxin signal transduction. We here present the first report of a genome-wide identification of SAUR genes in watermelon genome. We successfully identified 65 ClaSAURs and provide a genomic framework for future study on these genes. Phylogenetic result revealed a Cucurbitaceae-specific SAUR subfamily and contribute to understanding of the evolutionary pattern of SAUR genes in plants. Quantitative RT-PCR analysis demonstrates the existed expression of 11 randomly selected SAUR genes in watermelon tissues. ClaSAUR36 was highly expressed in fruit, for which further study might bring a new prospective for watermelon fruit development. Moreover, correlation analysis revealed the similar expression profiles of SAUR genes between watermelon and Arabidopsis during shoot organogenesis. This work gives us a new support for the conserved auxin machinery in plants.

Study of the structures of photodegradation impurities and pathways of photodegradation of cilnidipine by liquid chromatography/Q-Orbitrap mass spectrometry.

RATIONALE: The structures of photodegradation impurities in cilnidipine were studied by liquid chromatography/Q-Orbitrap mass spectrometry (LC/Q-Orbitrap MS) for the further improvement of the official monographs in Pharmacopoeias. The complete fragmentation patterns of impurities were investigated to obtain their structural information. Two pathways of photodegradation of cilnidipine were also explored to clarify the source of impurities in cilnidipine. METHODS: Chromatographic separation was performed on a Boston Group C18 column (250 mm × 4.6 mm, 5 µm). The mobile phase consisted of acetonitrile/H2 O at a ratio of 75:25 (v/v). In order to determine the m/z values of the molecular ions and formulas of all detected impurities, full scan LC/MS in both positive and negative ion modes was firstly performed using a Thermo LC system coupled with a Q-Orbitrap high-resolution mass spectrometer. LC/MS/MS analysis was also carried out on target compounds to obtain as much structural information as possible. RESULTS: Five novel photodegradation impurities of cilnidipine were separated and identified based on the high-resolution MS/MS data. Impurity III was synthesized and its structure was confirmed by (1) H-NMR and (13) C-NMR data. Two photodegradation pathways to produce different photodegradation impurities were also revealed in this study. CONCLUSIONS: Among those impurities, impurities II and III were the main impurities which existed in the cilnidipine available on the market. Impurity II (the Z-isomer) was mainly produced when cilnidipine powder was directly exposed to daylight while impurity III (containing a piperidine ring) was mainly produced when cilnidipine was exposed to daylight in an ethanolic solution. Copyright © 2016 John Wiley & Sons, Ltd.

Cluster precursors of uncapped CdS quantum dots via electroporation of synthetic liposomes. Experiments and theory.

Subnanometer size cluster precursors of uncapped CdS quantum dots were produced via the electroporation of synthetic dioleoylphosphatidylcholine (DOPC) unilamellar bilayer vesicles of mean hydrodynamic diameter Dh = 175 nm. During electroporation, Cd2+ ions are ejected from the interior compartments of the vesicles into the bulk solution where they react with S(2-) ions to form CdS monomers. The monomers adsorb on the exterior surface of the vesicles, where their spontaneous self-aggregation to (CdS)n clusters occurs on the hour and day time scale. The stepwise growth of the clusters was monitored through the time evolution of the UV absorption spectrum of the solution. The process is characterized by initial stepwise blue shifts of the absorption maxima: 285 nm --> 269 nm --> 245/275 nm --> 240 nm --> 236 nm, followed by a red shift to 494 nm. Nonlocal density functional theory (DFT) calculations of the optimized geometry and HOMO-LUMO gap of (CdS)n particles with n = 1-6 were carried out. The optimized structures are characterized by strong Cd-Cd bonds, with the S atoms bridging those bonds or capping the faces of the Cd polyhedra. The structure of such clusters bears no resemblance to fragments of the bulk crystal. The trend of the calculated HOMO-LUMO gaps facilitates the attribution of aggregation numbers (n) to particular clusters responsible for the observed absorption bands: n = 1 (285 nm), n = 2 (269 nm), n = 4 (245/275 nm --> 240 nm), n = 5 (236 nm), and larger quantum dots absorbing around 494 nm. The multiple bands assigned to the tetramer reflect the existence of its two distinct structures with similar stability.

Preparation of ultrasmall, uncapped PbS quantum dots via electroporation of vesicles.

Electric-field-induced transient pore formation (electroporation) in synthetic unilamellar dioleoylphosphatidylcholine vesicles of 178-nm diameter is utilized for the preparation of subnanometer-size PbS quantum dots. With Pb2+ ions originally entrapped in the vesicles and S2- ions placed in the bulk, their reaction is initiated by the opening of pores and occurs in the bulk. The ensuing self-aggregation of PbS is slowed to the hour and day time scales by its adsorption at the exterior surface of the vesicles. The growth of the particles in the molecular size regime is found to exhibit novel, time-dependent, oscillating red and blue shifts of the characteristic UV absorption band. On the basis of similarities between the oscillating trend of the experimentally observed transition energy and that of the calculated highest occupied molecular orbital-lowest unoccupied molecular orbital gap of (PbS)n clusters with n = 1-9, the wavelengths of the sequential spectral peaks can be assigned to the PbS monomer (237.5 nm), dimer (282 nm), tetramer (232 nm), hexamer (281 nm), octamer (234.5 nm), and nonamer (278-280 nm). Growth beyond the octamer is associated with the customary monotonic red shift of the absorption band. Under the experimental conditions used, a stable system is reached with unchanging spectral features after 20 days. This solution is estimated to contain 1.82 x 10(-5) M (PbS)9 particles, each with a greatest dimension of <9 A.

Density functional study of the structures of lead sulfide clusters (PbS)n (n = 1-9).

The structures of (PbS)n (n = 1-9) clusters are investigated with density functional theory at the B3LYP level. Various pseudopotential basis sets on lead and the 6-31+G basis set on sulfur were employed. Full geometry optimization and extensive searches of the potential energy surface were carried out for clusters with n = 1-6. We find that even small PbS clusters (n > 2) start to take on the characteristic features of the rock salt structure of solid-state PbS (galena). The origin of some of the structural aspects of these crystals is shown to be associated with the partial covalent nature of the Pb-S bond. The magnitude of the HOMO-LUMO gap oscillates with increasing size of the clusters, in agreement with the observed behavior of the corresponding UV absorption bands of ultrasmall PbS quantum dots. Direct conformation of this oscillation was found by CIS(D) calculations, for which the absorption with the largest oscillator strength oscillates as the clusters grow from PbS to (PbS)9.

Growth of uncapped, subnanometer size gold clusters prepared via electroporation of vesicles.

Electric-field-induced transient pore formation (electroporation) in synthetic unilamellar vesicles is utilized for the preparation of subnanometer size uncapped gold quantum dots. With the precursor AuCl4(-) placed in the aqueous bulk solution and the reducing agent BH4(-) originally entrapped in the vesicles' compartments, the redox reaction--that occurs in the bulk--is initiated by the opening of transient pores in the vesicles' bilayers. The absence of caps permits (i) continued growth of the Au clusters formed, (ii) the assessment of their true absorption spectra unaltered by stabilizing ligands, and (iii) the previously inaccessible live observation of the growth of the clusters in the molecular size regime. The normally rapid self-aggregation of Au atoms is slowed to the time scales of hour and week by their adsorption at the exterior surface of the vesicles. The UV spectra exhibit novel, time-dependent, oscillating red and blue shifts of the characteristic absorption band, which can be attributed to the evolution of cluster size transiently halting at magic aggregation numbers corresponding to Au2, Au8, Au20, and Au34. Subsequent growth is associated with a monotonic red shift of the absorption band up to the characteristic surface plasmon absorption at 520 nm.