Photoinitiator-free micro/nano fabrication of biomaterials with nonlinear deep UV excitation

Two-photon fabrication is expected to be a technique for fabricating biological tissues for regenerative medicine and drug discovery because of its capability of fabricating 3D structures on a subcellular scale. In this study, we conducted two-photon fabrication of biocompatible materials without photoinitiators. By using a visible-wavelength femtosecond pulsed laser as excitation light, two-photon polymerization is induced in deep UV absorbing moieties without the use of photo-initiators. We performed 3D micro/nanofabrication of a biocompatible hydrogel material. By using Raman spectral change, we investigated the photo-chemical process of the biocompatible upon the irradiation of visible pulsed laser light.SPIE OPTO, 22 January - 28 February 2022, San Francisco, California, United State

Functional and structural characterization of Streptococcus pneumoniae pyruvate kinase involved in fosfomycin resistance

Glycolysis is the primary metabolic pathway in the strictly fermentative Streptococcus pneumoniae, which is a major human pathogen associated with antibiotic resistance. Pyruvate kinase (PYK) is the last enzyme in this pathway that catalyzes the production of pyruvate from phosphoenolpyruvate (PEP) and plays a crucial role in controlling carbon flux; however, while S. pneumoniae PYK (SpPYK) is indispensable for growth, surprisingly little is known about its functional properties. Here, we report that compromising mutations in SpPYK confers resistance to the antibiotic fosfomycin, which inhibits the peptidoglycan synthesis enzyme MurA, implying a direct link between PYK and cell wall biogenesis. The crystal structures of SpPYK in the apo and ligand-bound states reveal key interactions that contribute to its conformational change as well as residues responsible for the recognition of PEP and the allosteric activator fructose 1,6-bisphosphate (FBP). Strikingly, FBP binding was observed at a location distinct from previously reported PYK effector binding sites. Furthermore, we show that SpPYK could be engineered to become more responsive to glucose 6-phosphate instead of FBP by sequence and structure-guided mutagenesis of the effector binding site. Together, our work sheds light on the regulatory mechanism of SpPYK and lays the groundwork for antibiotic development that targets this essential enzyme.Taguchi A., Nakashima R., Nishino K.. Functional and structural characterization of Streptococcus pneumoniae pyruvate kinase involved in fosfomycin resistance. Journal of Biological Chemistry 299, 104892 (2023); https://doi.org/10.1016/j.jbc.2023.104892

Structural Basis of Nucleotide Selectivity in Pyruvate Kinase

Taguchi A., Nakashima R., Nishino K. Structural Basis of Nucleotide Selectivity in Pyruvate Kinase. Journal of Molecular Biology 436, 168708 (2024); https://doi.org/10.1016/j.jmb.2024.168708.Nucleoside triphosphates are indispensable in numerous biological processes, with enzymes involved in their biogenesis playing pivotal roles in cell proliferation. Pyruvate kinase (PYK), commonly regarded as the terminal glycolytic enzyme that generates ATP in tandem with pyruvate, is also capable of synthesizing a wide range of nucleoside triphosphates from their diphosphate precursors. Despite their substrate promiscuity, some PYKs show preference towards specific nucleotides, suggesting an underlying mechanism for differentiating nucleotide bases. However, the thorough characterization of this mechanism has been hindered by the paucity of nucleotide-bound PYK structures. Here, we present crystal structures of Streptococcus pneumoniae PYK in complex with four different nucleotides. These structures facilitate direct comparison of the protein-nucleotide interactions and offer structural insights into its pronounced selectivity for GTP synthesis. Notably, this selectivity is dependent on a sequence motif in the nucleotide recognition site that is widely present among prokaryotic PYKs, particularly in Firmicutes species. We show that pneumococcal cell growth is significantly impaired when expressing a PYK variant with compromised GTP and UTP synthesis activity, underscoring the importance of PYK in maintaining nucleotide homeostasis. Our findings collectively advance our understanding of PYK biochemistry and prokaryotic metabolism

CO oxidation on perovskite-type LaCoO3 synthesized using ethylene glycol and citric acid

In order to synthesize perovskite-type LaCoO3 with good surface crystallinity, the gel prepared by adding both ethylene glycol (EG) and citric acid (CA) to the aqueous solution of La(NO3)3 center dot 6H(2)O and Co(NO3)(2) center dot 6H(2)O was fired at 600 degrees C in air for 3 h. The transmission electron microscopy (TEM) observation indicated that the particles of LaCoO3 tended to have a uniform shape at EG/CA = 4. Although, the specific surface area of LaCoO3 synthesized using both EG and CA was slightly smaller than that of LaCoO3 synthesized using only CA, the catalytic activity of CO oxidation became higher by adding EG

On the Untapped Potential of the Quantum FLT-based Inversion

Thus far, several papers estimated concrete quantum resources of Shor’s algorithm for solving a binary elliptic curve discrete logarithm problem. In particular, the complexity of computing quantum inversions over a binary field F2n is dominant when running the algorithm, where n is a degree of a binary elliptic curve. There are two major methods for quantum inversion, i.e., the quantum GCD-based inversion and the quantum FLT-based inversion. Among them, the latter method is known to require more qubits; however, the latter one is valuable since it requires much fewer Toffoli gates and less depth. When n = 571, Kim-Hong’s quantum GCD-based inversion algorithm (Quantum Information Processing 2023) and Taguchi-Takayasu’s quantum FLT-based inversion algorithm (CT-RSA 2023) require 3, 473 qubits and 8, 566 qubits, respectively. In contrast, for the same n = 571, the latter algorithm requires only 2.3% of Toffoli gates and 84% of depth compared to the former one. In this paper, we modify Taguchi-Takayasu’s quantum FLT-based inversion algorithm to reduce the required qubits. While Taguchi-Takayasu’s FLT-based inversion algorithm takes an addition chain for n−1 as input and computes a sequence whose number is the same as the length of the chain, our proposed algorithm employs an uncomputation step and stores a shorter one. As a result, our proposed algorithm requires only 3, 998 qubits for n = 571, which is only 15% more than Kim-Hong’s GCD-based inversion algorithm. Furthermore, our proposed algorithm preserves the advantage of FLT-based inversion since it requires only 3.7% of Toffoli gates and 77% of depth compared to Kim-Hong’s GCD-based inversion algorithm for n = 571

Concrete Quantum Cryptanalysis of Binary Elliptic Curves via Addition Chain

Thus far, several papers reported concrete resource estimates of Shor\u27s quantum algorithm for solving the elliptic curve discrete logarithm problem (ECDLP). In this paper, we study quantum FLT-based inversion algorithms over binary elliptic curves. There are two major algorithms proposed by Banegas et al. and Putranto et al., where the former and latter algorithms achieve fewer numbers of qubits and smaller depths of circuits, respectively. We propose two quantum FLT-based inversion algorithms that essentially outperform previous FLT-based algorithms and compare the performance for NIST curves of the degree $n$. Specifically, for all $n$, our first algorithm achieves fewer qubits than Putranto et al.\u27s one without sacrificing the number of Toffoli gates and the depth of circuits, while our second algorithm achieves smaller depths of circuits without sacrificing the number of qubits and Toffoli gates. For example, when $n = 571$, the number of qubits of our first algorithm is 74 \% of that of Putranto et al.\u27s one, while the depth of our second algorithm is 83 \% of that of Banegas et al.\u27s one. The improvements stem from the fact that FLT-based inversions can be performed with arbitrary sequences of addition chains for $n - 1$ although both Banegas et al. and Putranto et al. follow fixed sequences that were introduced by Itoh and Tsujii\u27s classical FLT-based inversion. In particular, we analyze how several properties of addition chains, which do not affect the computational resources of classical FLT-based inversions, affect the computational resources of quantum FLT-based inversions and find appropriate sequences

含歯性嚢胞より生じた原発性骨内歯原性癌腫

Malignant tumors arising from dentigerous cysts are classified as primary squamous cell carcinoma derived from an odontogenic cyst or as odontogenic carcinoma according to the 2005 WHO classification and are extremely rare. We report a malignant tumor arising from a dentigerous cyst in the right maxillary anterior teeth , together with a literature review. The patient was a 75-year-old man who visited a hospital with complaining of discomfort in the lingual part of the right maxillary anterior teeth. On panoramic radiography and plain computed tomography (CT), dentigerous cyst, keratocystic odontogenic tumor or ameloblastoma was suspected. The extirpated material was histopathologically diagnosed as an odontogenic carcinoma (in situ) arising from the dentigerous cyst. Postoperative ultrasonography (US) and contrast enhanced CT revealed no metastasis to the cervical lymph nodes. The patient is currently being followed up without resection or anticancer drug administration. Neither local recurrence nor metastases were observed 18 month after surgery.症例は75歳男性で、右上顎前歯の舌部不快感を主訴として受診した。パノラマX線撮影とCT検査により含歯性嚢胞、角化細胞歯原性腫瘍またはエナメル上皮腫が疑われた。切除切片の病理組織学的検査の結果、含歯性嚢胞より生じた歯原性癌腫と診断した。術後超音波検査と造影増強CT画像では頸部リンパ節への転移は見られなかった。抗癌剤投与はせずに経過観察中で、術後18ヵ月時点で再発や転移は見られていない。含歯性嚢胞より生じる悪性腫瘍は2005年のWHO分類によれば歯原性嚢胞由来の原発性扁平上皮癌または歯原性癌腫に分類され、極めて稀である。本症例は右上顎前歯の含歯性嚢胞より生じた悪性腫瘍であった。他の症例についても文献レビューした