Connected in diversity: Isotopic analysis refines provenance for Islamic plant-ash glass from the eastern Silk Roads.

Our understanding of glass production in Eurasia has been built mostly on evidence from Europe and the Mediterranean. Here, we investigate the occurrence and organization of plant-ash glass production in the eastern continental Islamic region, focusing on an 11th-12th century assemblage unearthed in Shadyakh, Nishapur, Iran. Through Sr-Nd isotope analysis and by examining geochemical contexts and mixing patterns, we find that distinct silica and ash sources originating from Tigris-Euphrates Basin, Central Asia, and potentially Iran were used to make these objects. Zagros-derived silica and Central-Asian-type silica were likely important silica sources for Islamic plant-ash glasses from east of the Tigris. Furthermore, we show that Central Asian glass can be characterized by chemical and isotopic signatures, while Iranian glass may exhibit overlapping signatures with glass from neighboring regions. The plant-ash glass industry in Islamic-period West and Central Asia likely thrived by exploiting and sharing diverse, regionally characteristic raw material sources.

Effects of different modified starches and gums on the physicochemical, functional, and microstructural properties of tapioca pearls.

The effects of different modified starch and gums on the physicochemical, functional, and microstructural properties of tapioca pearls were investigated. The addition of starch acetate (SA) and carboxymethylcellulose (CMC) improved the springiness, hardness, cooking properties, and overall acceptability of pearls. Samples added with CMC presented higher peak viscosities, breakdown viscosities, onset gelatinization temperature, and lower enthalpy of gelatinization values compared to control pearls. Furthermore, Rheology and LF-NMR results indicated that all five kinds of modifiers promoted the formation of tighter network structures in products. SEM showed that the addition of SA and hydroxypropyl distarch phosphate (HDP) could fill the voids in the internal gel network of the pearls, thus promoting the formation of a continuous phase network. This study proved SA, HDP, and CMC as modifiers could have tremendous potential to improve the quality of pearls before and after cooking.

Natron glass beads reveal proto-Silk Road between the Mediterranean and China in the 1st millennium BCE.

Natron-based glass was a vital part of material culture in the Mediterranean and Europe for nearly two millennia, but natron glass found elsewhere on the Eurasian Continent has not received adequate discussion, despite its influence on ancient Asian glass. Here we present a new interpretation of natron glass finds from both the West and the East. After establishing the compositional types and technological sequence of Mediterranean natron glass (eighth-second century BCE) using trace elements, we report the analysis of a mid-1st millennium BCE glass bead from Xinjiang, China, which was likely made with Levantine raw glass, and identify common types of stratified eye beads in Eurasia based on a compositional and typological comparison. Combining these findings, we propose that a considerable number of Mediterranean natron glass products had arrived in East Asia at least by the fifth century BCE, which may have been a contributing factor in the development of native Chinese glass-making. The swift diffusion of natron glass across Eurasia in the 1st millennium BCE was likely facilitated by a three-stage process involving maritime and overland networks and multiple forms of trade and exchange, indicating a highly adaptable and increasingly efficient transcontinental connection along the 'Proto-Silk Road'.

Erratum to "The Possibility of Changing the Wettability of Material Surface by Adjusting Gravity".

[This corrects the article DOI: 10.34133/2020/2640834.].

Redefining Pyropia (Bangiales, Rhodophyta): Four New Genera, Resurrection of Porphyrella and Description of Calidia pseudolobata sp. nov. From China.

The cosmopolitan red algal genus Pyropia sensu lato is the most speciose of the bladed Bangiales genera. In a major revision of the Bangiales, Pyropia was resurrected from Porphyra, although there was evidence at the time that species of Pyropia could be separated into several genera. Subsequent global phylogenetic analyses continued to resolve species assigned to Pyropia into several major clades with strong support, and the latest biogeographic analyses indicated that species distribution was also a pointer to the underlying phylogeny of Pyropia sensu lato. Therefore, in the present study, we have redefined the genus Pyropia, resurrected Porphyrella, and proposed four new genera: Calidia, Neoporphyra, Neopyropia, and Uedaea. Based on a molecular phylogenetic study of the bladed Bangiales of China, a species which did not match any known taxa was resolved in the new genus Calidia. The species, Calidia pseudolobata sp. nov., is described based on both morphological and molecular data. Molecular sequence data for rbcL, 18S, and COI-5P were amplified for 15 samples in the present study. All the obtained rbcL sequences were identical to each other except for one (LYCN117) with one base pair difference. Two haplotypes of 18S (V9 region) were observed with one base pair difference (C/T30 ). All the obtained COI-5P sequences were identical. Morphological comparisons were conducted not only with species in Calidia, but also with generically uncertain species currently assigned to Porphyra.

The Possibility of Changing the Wettability of Material Surface by Adjusting Gravity.

The contact angle, as a vital measured parameter of wettability of material surface, has long been in dispute whether it is affected by gravity. Herein, we measured the advancing and receding contact angles on extremely low contact angle hysteresis surfaces under different gravities (1-8G) and found that both of them decrease with the increase of the gravity. The underlying mechanism is revealed to be the contact angle hysteresis and the deformation of the liquid-vapor interface away from the solid surface caused by gradient distribution of the hydrostatic pressure. The real contact angle is not affected by gravity and cannot measured by an optical method. The measured apparent contact angles are angles of inclination of the liquid-vapor interface away from the solid surface. Furthermore, a new equation is proposed based on the balance of forces acting on the three-phase contact region, which quantitatively reveals the relation of the apparent contact angle with the interfacial tensions and gravity. This finding can provide new horizons for solving the debate on whether gravity affects the contact angle and may be useful for the accurate measurement of the contact angle and the development of a new contact angle measurement system.

Functional Characterization of Lycopene Cyclases Illustrates the Metabolic Pathway toward Lutein in Red Algal Seaweeds.

Carotenoids are essential phytonutrients synthesized by all photosynthetic organisms. Acyclic lycopene is the first branching point for carotenoid biosynthesis. Lycopene ß- and ε-cyclases (LCYB and LCYE, respectively) catalyze the cyclization of its open ends and direct the metabolic flux into different downstream branches. Carotenoids of the ß,ß-branch (e.g., ß-carotene) are found in all photosynthetic organisms, but those of the ß,ε-branch (e.g., lutein) are generally absent in cyanobacteria, heterokonts, and some red algae. Although both LCYBs and LCYEs have been characterized from land plants, there are only a few reports on LCYs from cyanobacteria and algae. Here, we cloned four LCY genes from Porphyra umbilicalis and Pyropia yezoensis (susabi-nori) of Bangiales, the most primitive red algal order that synthesizes lutein. Our functional characterization in both Escherichia coli and Arabidopsis thaliana demonstrated that each species has a pair of LCYB and LCYE. Similar to LCYs from higher plants, red algal LCYBs cyclize both ends of lycopene, and their LCYEs only cyclize a single end. The characterization of LCYEs from red algae resolved the first bifurcation step toward ß-carotene and lutein biosynthesis. Our phylogenetic analysis suggests that LCYEs of the green lineage and the red algae originated separately during evolution.

A molecular phylogeny of the bladed Bangiales (Rhodophyta) in China provides insights into biodiversity and biogeography of the genus Pyropia.

A molecular taxonomic study was undertaken for the first time of the bladed Bangiales of the mainland coast of China (Northwest Pacific) based on sequence data of 201 plastid rbcL and 148 nuclear 18S sequences of historical and contemporary specimens. The results revealed that only one genus of bladed Bangiales, Pyropia, was present along Chinese coast. Species delimitation was determined using two empirical methods: the Automatic Barcode Gap Discovery (ABGD) and General Mixed Yule Coalescence (GMYC) coupled with detection of monophyly in tree reconstruction. At least fourteen species of Pyropia were recovered. Six species were confirmed that had been recorded previously based on morphology (Py. suborbiculata, Py. yezoensis, Py. haitanensis, Py. katadae, Py. tenera and Py. acanthophora), three species were recorded from China for the first time (Py. kinositae, Py. pseudolinearis and Py. tanegashimensis), and five cryptic species that did not match any molecular sequences were also discovered. The phylogeny of the concatenated rbcL and 18S dataset resolved three singletons and four clades. Each clades has a strong trend towards occupying a biogeographic region, but they are not confined to them. A transoceanic and antitropical pattern of distribution was found for Pyropia at both the subgeneric and species level. This together with high biodiversity (ca. 30% of all known Pyropia species) indicates that the Northwest Pacific might act as a centre of origin for modern distribution of Pyropia since the early Cenozoic.

Preparation of cross-linked hen-egg white lysozyme crystals free of cracks.

Cross-linked protein crystals (CLPCs) are very useful materials in applications such as biosensors, catalysis, and X-ray crystallography. Hence, preparation of CLPCs is an important research direction. During the preparation of CLPCs, an often encountered problem is that cracks may appear in the crystals, which may finally lead to shattering of the crystals into small pieces and cause problem in practical applications. To avoid cross-link induced cracking, it is necessary to study the cracking phenomenon in the preparation process. In this paper, we present an investigation on how to avoid cracking during preparation of CLPCs. An orthogonal experiment was designed to study the phenomenon of cross-link induced cracking of hen-egg white lysozyme (HEWL) crystals against five parameters (temperature, solution pH, crystal growth time, glutaraldehyde concentration, and cross-linking time). The experimental results showed that, the solution pH and crystal growth time can significantly affect cross-link induced cracking. The possible mechanism was studied, and optimized conditions for obtaining crack-free CLPCs were obtained and experimentally verified.

A Systematic Analysis of the Structures of Heterologously Expressed Proteins and Those from Their Native Hosts in the RCSB PDB Archive.

Recombinant expression of proteins has become an indispensable tool in modern day research. The large yields of recombinantly expressed proteins accelerate the structural and functional characterization of proteins. Nevertheless, there are literature reported that the recombinant proteins show some differences in structure and function as compared with the native ones. Now there have been more than 100,000 structures (from both recombinant and native sources) publicly available in the Protein Data Bank (PDB) archive, which makes it possible to investigate if there exist any proteins in the RCSB PDB archive that have identical sequence but have some difference in structures. In this paper, we present the results of a systematic comparative study of the 3D structures of identical naturally purified versus recombinantly expressed proteins. The structural data and sequence information of the proteins were mined from the RCSB PDB archive. The combinatorial extension (CE), FATCAT-flexible and TM-Align methods were employed to align the protein structures. The root-mean-square distance (RMSD), TM-score, P-value, Z-score, secondary structural elements and hydrogen bonds were used to assess the structure similarity. A thorough analysis of the PDB archive generated five-hundred-seventeen pairs of native and recombinant proteins that have identical sequence. There were no pairs of proteins that had the same sequence and significantly different structural fold, which support the hypothesis that expression in a heterologous host usually could fold correctly into their native forms.

An ignored variable: solution preparation temperature in protein crystallization.

Protein crystallization is affected by many parameters, among which certain parameters have not been well controlled. The temperature at which the protein and precipitant solutions are mixed (i.e., the ambient temperature during mixing) is such a parameter that is typically not well controlled and is often ignored. In this paper, we show that this temperature can influence protein crystallization. The experimental results showed that both higher and lower mixing temperatures can enhance the success of crystallization, which follows a parabolic curve with an increasing ambient temperature. This work illustrates that the crystallization solution preparation temperature is also an important parameter for protein crystallization. Uncontrolled or poorly controlled room temperature may yield poor reproducibility in protein crystallization.

The P450-type carotene hydroxylase PuCHY1 from Porphyra suggests the evolution of carotenoid metabolism in red algae.

Carotene hydroxylases catalyze the hydroxylation of α- and ß-carotene hydrocarbons into xanthophylls. In red algae, ß-carotene is a ubiquitously distributed carotenoid, and hydroxylated carotenoids such as zeaxanthin and lutein are also found. However, no enzyme with carotene hydroxylase activity had been previously identified in red algae. Here, we report the isolation of a gene encoding a cytochrome P450-type carotene hydroxylase (PuCHY1) from Porphyra umbilicalis, a red alga with an ancient origin. Sequence comparisons found PuCHY1 belongs to the CYP97B subfamily, which has members from different photosynthetic organisms ranging from red algae to land plants. Functional complementation in Escherichia coli suggested that PuCHY1 catalyzed the conversion from ß-carotene to zeaxanthin. When we overexpressed PuCHY1 in the Arabidopsis thaliana chy2 mutant, pigment analysis showed a significant accumulation of hydroxylated carotenoids, including neoxanthin, violaxanthin, and lutein in the leaves of transgenic plants. These results confirmed a ß-hydroxylation activity of PuCHY1, and also suggested a possible ϵ-hydroxylation function. The pigment profile and gene expression analyses of the algal thallus under high-light stress suggested that P. umbilicalis is unlikely to operate a partial xanthophyll cycle for photoprotection.

Promoting protein crystallization using a plate with simple geometry.

Increasing the probability of obtaining protein crystals in crystallization screening is always an important goal for protein crystallography. In this paper, a new method called the cross-diffusion microbatch (CDM) method is presented, which aims to efficiently promote protein crystallization and increase the chance of obtaining protein crystals. In this method, a very simple crystallization plate was designed in which all crystallization droplets are in one sealed space, so that a variety of volatile components from one droplet can diffuse into any other droplet via vapour diffusion. Crystallization screening and reproducibility tests indicate that this method could be a potentially powerful technique in practical protein crystallization screening. It can help to obtain crystals with higher probability and at a lower cost, while using a simple and easy procedure.

Sensitivity of lysozyme crystallization to minute variations in concentration.

It is well known that the crystallization of proteins is strongly dependent on the crystallization conditions, which are sometimes very sensitive to environmental disturbances. Parameters such as the concentration of precipitants or protein, pH, temperature and many others are known to affect the probability of crystallization, and the task of crystallizing a new protein often involves a trial-and-error test using numerous combinations of crystallization conditions. These crystallization parameters, such as the concentration of either the protein or the precipitant, are important because they directly affect the driving force of crystallization: the supersaturation of the solution. Although it is common sense that the concentration can affect the crystallization process, the sensitivity of the crystallization process to variations in the concentration has seldom been addressed. Owing to the difficulty of directly preparing solutions with very small concentration variations, it is hard to carry out an investigation of their effect on the crystallization process. In this paper, a simple but novel method for studying the effect of minute concentration variations on the success rate of protein crystallization is presented. By evaporating the crystallization droplet, a fine concentration gradient could be created. With this fine-tuned concentration gradient, it was possible to observe the effects of minute variations in the concentration or supersaturation on the crystallization. A very minor change in concentration (as low as 0.13% of the initial concentration, i.e. 0.026 mg ml(-1) for lysozyme and 0.052 mg ml(-1) for NaCl in the current study) or a very minor change in supersaturation (as small as 0.018) could cause a clear difference in the crystallization success rate, indicating that the crystallization of proteins is very sensitive to the concentration level. Such sensitive behaviour may be one reason for the poor reproducibility of protein crystallization.

Selecting temperature for protein crystallization screens using the temperature dependence of the second virial coefficient.

Protein crystals usually grow at a preferable temperature which is however not known for a new protein. This paper reports a new approach for determination of favorable crystallization temperature, which can be adopted to facilitate the crystallization screening process. By taking advantage of the correlation between the temperature dependence of the second virial coefficient (B(22)) and the solubility of protein, we measured the temperature dependence of B(22) to predict the temperature dependence of the solubility. Using information about solubility versus temperature, a preferred crystallization temperature can be proposed. If B(22) is a positive function of the temperature, a lower crystallization temperature is recommended; if B(22) shows opposite behavior with respect to the temperature, a higher crystallization temperature is preferred. Otherwise, any temperature in the tested range can be used.

A containerless levitation setup for liquid processing in a superconducting magnet.

Containerless processing of materials is considered beneficial for obtaining high quality products due to the elimination of the detrimental effects coming from the contact with container walls. Many containerless processing methods are realized by levitation techniques. This paper describes a containerless levitation setup that utilized the magnetization force generated in a gradient magnetic field. It comprises a levitation unit, a temperature control unit, and a real-time observation unit. Known volume of liquid diamagnetic samples can be levitated in the levitation chamber, the temperature of which is controlled using the temperature control unit. The evolution of the levitated sample is observed in real time using the observation unit. With this setup, containerless processing of liquid such as crystal growth from solution can be realized in a well-controlled manner. Since the levitation is achieved using a superconducting magnet, experiments requiring long duration time such as protein crystallization and simulation of space environment for living system can be easily succeeded.