Black surfaces on ancient leather tefillin cases and straps from the Judean Desert: Macroscopic, microscopic and spectroscopic analyses.

Tefillin are Jewish ritual artifacts consisting of leather cases, containing inscribed slips, which are affixed with leather straps to the body of the tefillin practitioner. According to current Jewish ritual law, the tefillin cases and straps are to be colored black. The present study examines seventeen ancient tefillin cases discovered among the Dead Sea Scrolls in caves in the Judean Desert. All seventeen cases display grain surfaces with a very dark, nearly black appearance. We start with a hypothesis that the cases were intentionally colored black in antiquity using either a carbon-based or iron-gall-based paint or dye. The aim of this study is to test this hypothesis by subjecting these tefillin cases to a battery of examinations to assess the presence of carbon and iron used as pigments, and of organic materials which may have been used as binding agents in a paint. The tests deployed are: (1) macroscopic and microscopic analyses; (2) multispectral imaging using infrared wavelengths; (3) Raman spectroscopy; (4) Fourier transform infrared spectroscopy (FTIR); and (5) scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy. The results of these tests found no traces of carbon-based or iron-gall-based pigments, nor of organic compounds which may have served as binders in a paint. These results suggest that our posited hypothesis is unlikely. Instead, results of the SEM examination suggest it more likely that the black color on the surfaces of the tefillin cases is the result of natural degradation of the leather through gelatinization. The Judean Desert tefillin likely represent tefillin practices prior to when the rabbinic prescription on blackening tefillin was widely practiced. Our study suggests that the kind of non-blackened tefillin which the later rabbis rejected in their own times may well have been quite common in earlier times.

Proteomics and metabolomics composition of the ink of a letter in a fragment of a Dead Sea Scroll from Cave 11 (P1032-Fr0).

It is well established that the ink pigment used for writing the Dead Sea Scrolls (DSS) is mainly composed of carbon soot. The ink's binder however has yet to be securely identified. By applying EVA (ethylene vinyl acetate containing strong anion and cation exchangers admixed with C8 and C18) diskettes on one fragment and analyzing the captured material, the following study was able to determine the composition of the binder. Proteins admixed of plant proteins (ribulose biphosphate carboxylase, rhamnogalacturonate lyase, α-galactosidase A, calmodulin, among those identified) as well as of a few glycoproteins with different combinations of pentosyl and hexosyl units with plant acids (stearic, palmitic, oleic, linoleic and linolenic acids) and terpenes (triacontanol, catechin, lupeol) are mixed attributes of acacia trees which suggests the use of gum Arabic as the ink's binder. SIGNIFICANCE: Whereas a huge body of reports has explored any possible aspect of the Dead Sea Scrolls, including the dating and the animal origin of the parchment, one aspect had not been investigated so far, namely which kind of ligand had been adopted to ensure a firm binding of the ink (in reality carbon soot) to the supporting parchment. In the present investigation it has been demonstrated that this "glue" is a mixture of plant proteins, as well as a few glycoproteins, together with plant acids and terpenes. These proteins and metabolites belong to two species of trees, Vachellia nilotica and Acacia Albida, widespread in this Middle East region. The EVA methodology here adopted has shown that it is possible to explore any item pertaining to the world Cultural Heritage in the absence of damage or contamination thus permititng to analyze any possible precious document stored in museum, public libraries and private collections.

Zinc-bacteriochlorophyllide dimers in de novo designed four-helix bundle proteins. A model system for natural light energy harvesting and dissipation.

Photosynthetic organisms utilize interacting pairs of chlorophylls and bacteriochlorophylls as excitation energy donors and acceptors in light harvesting complexes, as photosensitizers of charge separation in reaction centers, and maybe as photoprotective quenching centers that dissipate excess excitation energy under high light intensities. To better understand how the pigment's local environment and spatial organization within the protein tune its ground- and excited-state properties to perform different functions, we prepared and characterized the simplest possible system of interacting bacteriochlorophylls within a protein scaffold. Using HP7, a high-affinity heme-binding protein of the HP class of de novo designed four-helix bundles, we incorporated 13(2)-OH-zinc-bacteriochlorophyllide-a (ZnBChlide), a water-soluble bacteriochlorophyll derivative, into specific binding sites within the four-helix bundle protein core. We capitalized on the rich and informative optical spectrum of ZnBChlide to rigorously characterize its complexes with HP7 and two variants, in which a single heme-binding site is eliminated by replacing histidine residues at positions 7 or 42 by phenylalanine. Surprisingly, we found the ZnBChlide binding capacity of HP7 and its variants to be higher than for heme: up to three ZnBChlide pigments bind per HP7, or two per each single histidine variant. The formation of dimers within HP7 results in dramatic quenching of ZnBChlide fluorescence, reducing its quantum yield by about 80%, and the singlet excited-state lifetime by 2 orders of magnitudes compared to the monomer. Thus, HP7 and its variants are the first examples of a simple protein environment that can isolate a self-quenching pair of photosynthetic pigments in pure form. Unlike its complicated natural analogues, this system can be constructed from the ground up, starting with the simplest functional element, increasing the complexity as needed.

Structural characterization of modern and fossilized charcoal produced in natural fires as determined by using electron energy loss spectroscopy.

Charcoal produced in natural fires is widespread, but surprisingly little is known about its structure and stability. TEM and electron energy loss spectroscopy (EELS) were used to characterize the organized graphite-like microcrystallites and amorphous nonorganized phases of modern charcoal that had been produced in natural fires. In addition, a semiordered structure was identified in two modern charcoal samples. Fossilized charcoal contains fewer graphite-like microcrystallites than modern samples. EELS spectra confirmed that the dominant structure in fossilized charcoal is amorphous carbon. EELS measurements also revealed that only the nonorganized phase contains oxygen, which indicates that the degradation of the fossilized charcoal structure occurs mainly through oxidation processes. The few graphite-like microcrystallites found in fossilized charcoal were composed of onion-like structures that are probably less prone to oxidation owing to their rounded structures.