Tumor formation in hybrids between Solanum lycopersicum and S. habrochaites

Genetic tumors are neoplastic growths that arise spontaneously in particular genotypes in plants. In the present study, we observed the occurrence of tumors in interspecific hybrids between Solanum lycopersicum L. and Solanum habrochaites S. Knapp and D. M. Spooner. The hybridity of these plants was confirmed based on morphological characteristics, flow cytometry and random amplified polymorphic DNA analysis. Hybrids formed tumors when the plants were grown in a growth chamber. These tumors were formed most frequently on leaves, but also on cotyledons, stems and petioles. When hybrid plants bearing tumors were transferred to a greenhouse, the tumors disappeared and necrotic brown spots were visible in the positions where tumors existed previously. Further analyses indicated that tumors were never formed in the greenhouse. These results suggest that environmental conditions influenced tumorigenesis in hybrids raised from S. lycopersicum × S. habrochaites crosses. In addition, when stem segments of hybrids were cultured in vitro on plant growth regulator-free medium, tumors and shoot formation were induced. Thus, hybrids between S. lycopersicum × S. habrochaites provide an excellent experimental system to study plant tumorigenesis and to understand cell division and differentiation.Keywords: Environmental condition, growth abnormality, interspecific cross, tomato, tissue culture, tumorAfrican Journal of Biotechnology Vol. 12(15), pp. 1745-175

Weakened Random Oracle Models with Target Prefix

Weakened random oracle models (WROMs) are variants of the random oracle model (ROM). The WROMs have the random oracle and the additional oracle which breaks some property of a hash function. Analyzing the security of cryptographic schemes in WROMs, we can specify the property of a hash function on which the security of cryptographic schemes depends. Liskov (SAC 2006) proposed WROMs and later Numayama et al. (PKC 2008) formalized them as CT-ROM, SPT-ROM, and FPT-ROM. In each model, there is the additional oracle to break collision resistance, second preimage resistance, preimage resistance respectively. Tan and Wong (ACISP 2012) proposed the generalized FPT-ROM (GFPT-ROM) which intended to capture the chosen prefix collision attack suggested by Stevens et al. (EUROCRYPT 2007). In this paper, in order to analyze the security of cryptographic schemes more precisely, we formalize GFPT-ROM and propose additional three WROMs which capture the chosen prefix collision attack and its variants. In particular, we focus on signature schemes such as RSA-FDH, its variants, and DSA, in order to understand essential roles of WROMs in their security proofs

Quantum Search-to-Decision Reduction for the LWE Problem

The learning with errors (LWE) problem is one of the fundamental problems in cryptography and it has many applications in post-quantum cryptography. There are two variants of the problem, the decisional-LWE problem, and the search-LWE problem. LWE search-to-decision reduction shows that the hardness of the search-LWE problem can be reduced to the hardness of the decisional-LWE problem. We initiate a study of quantum search-to-decision reduction for the LWE problem and propose a reduction that satisfies sample-preserving. In sample-preserving reduction, it preserves all parameters even the number of instances. Especially, our quantum reduction invokes the distinguisher only $2$ times to solve the search-LWE problem, while classical reductions require a polynomial number of invocations. Furthermore, we give a way to amplify the success probability of the reduction algorithm. Our amplified reduction works with fewer LWE samples compared to the classical reduction that has a high success probability. Our reduction algorithm supports a wide class of error distributions and also provides a search-to-decision reduction for the learning parity with noise problem. In the process of constructing the search-to-decision reduction, we give a quantum Goldreich-Levin theorem over $\mathbb{Z}_q$ where $q$ is prime. In short, this theorem states that, if a hardcore predicate $a\cdot s \pmod q$ can be predicted with probability distinctly greater than $1/q$ with respect to a uniformly random $a\in\mathbb{Z}_q^n$, then it is possible to determine $s\in\mathbb{Z}_q^n$

Identification of Nicotiana tabacum Linkage Group Corresponding to the Q Chromosome Gene(s) Involved in Hybrid Lethality

BACKGROUND: A linkage map consisting of 24 linkage groups has been constructed using simple sequence repeat (SSR) markers in Nicotiana tabacum. However, chromosomal assignments of all linkage groups have not yet been made. The Q chromosome in N. tabacum encodes a gene or genes triggering hybrid lethality, a phenomenon that causes death of hybrids derived from some crosses. METHODOLOGY/PRINCIPAL FINDINGS: We identified a linkage group corresponding to the Q chromosome using an interspecific cross between an N. tabacum monosomic line lacking the Q chromosome and N. africana. N. ingulba yielded inviable hybrids after crossing with N. tabacum. SSR markers on the identified linkage group were used to analyze hybrid lethality in this cross. The results implied that one or more genes on the Q chromosome are responsible for hybrid lethality in this cross. Furthermore, the gene(s) responsible for hybrid lethality in the cross N. tabacum × N. africana appear to be on the region of the Q chromosome to which SSR markers PT30342 and PT30365 map. CONCLUSIONS/SIGNIFICANCE: Linkage group 11 corresponded to the Q chromosome. We propose a new method to correlate linkage groups with chromosomes in N. tabacum

Deficient of a Clock Gene, Brain and Muscle Arnt-Like Protein-1 (BMAL1), Induces Dyslipidemia and Ectopic Fat Formation

A link between circadian rhythm and metabolism has long been discussed. Circadian rhythm is controlled by positive and negative transcriptional and translational feedback loops composed of several clock genes. Among clock genes, the brain and muscle Arnt-like protein-1 (BMAL1) and circadian locomotor output cycles kaput (CLOCK) play important roles in the regulation of the positive rhythmic transcription. In addition to control of circadian rhythm, we have previously shown that BMAL1 regulates adipogenesis. In metabolic syndrome patients, the function of BMAL1 is dysregulated in visceral adipose tissue. In addition, analysis of SNPs has revealed that BMAL1 is associated with susceptibility to hypertension and type II diabetes. Furthermore, the significant roles of BMAL1 in pancreatic β cells proliferation and maturation were recently reported. These results suggest that BMAL1 regulates energy homeostasis. Therefore, in this study, we examined whether loss of BMAL1 function is capable of inducing metabolic syndrome. Deficient of the Bmal1 gene in mice resulted in elevation of the respiratory quotient value, indicating that BMAL1 is involved in the utilization of fat as an energy source. Indeed, lack of Bmal1 reduced the capacity of fat storage in adipose tissue, resulting in an increase in the levels of circulating fatty acids, including triglycerides, free fatty acids, and cholesterol. Elevation of the circulating fatty acids level induced the formation of ectopic fat in the liver and skeletal muscle in Bmal1 -/- mice. Interestingly, ectopic fat formation was not observed in tissue-specific (liver or skeletal muscle) Bmal1 -/- mice even under high fat diet feeding condition. Therefore, we were led to conclude that BMAL1 is a crucial factor in the regulation of energy homeostasis, and disorders of the functions of BMAL1 lead to the development of metabolic syndrome

Redactable Signature with Compactness from Set-Commitment

Redactable signature allows anyone to remove parts of a signed message without invalidating the signature. The need to prove the validity of digital documents issued by governments is increasing. When governments disclose documents, they must remove private information concerning individuals. Redactable signature is useful for such a situation. However, in most redactable signature schemes, to remove parts of the signed message, we need pieces of information for each part we want to remove. If a signed message consists of l elements, the number of elements in an original signature is at least linear in l. As far as we know, in some redactable signature schemes, the number of elements in an original signature is constant, regardless of the number of elements in a message to be signed. However, these constructions have drawbacks in that the use of the random oracle model or generic group model. In this paper, we construct an efficient redactable signature to overcome these drawbacks. Our redactable signature is obtained by combining set-commitment proposed in the recent work by Fuchsbauer et al. (JoC 2019) and digital signatures

Improved Security Proof for the Camenisch-Lysyanskaya Signature-Based Synchronized Aggregate Signature Scheme

The Camenisch-Lysyanskaya signature scheme in CRYPTO 2004 is a useful building block to construct privacy-preserving schemes such as anonymous credentials, group signatures or ring signatures. However, the security of this signature scheme relies on the interactive assumption called the LRSW assumption. Even if the interactive assumptions are proven in the generic group model or bilinear group model, the concerns about these assumptions arise in a cryptographic community. This fact caused a barrier to the use of cryptographic schemes whose security relies on these assumptions. Recently, Pointcheval and Sanders proposed the modified Camenisch-Lysyanskaya signature scheme in CT-RSA 2018. This scheme satisfies the EUF-CMA security under the new q-type assumption called the Modified-q-Strong Diffie-Hellman-2 (q-MSDH-2) assumption. However, the size of a q- type assumptions grows dynamically and this fact leads to inefficiency of schemes. In this work, we revisit the Camenisch-Lysyanskaya signature-based synchronized aggregate signature scheme in FC 2013. This scheme is one of the most efficient synchronized aggregate signature schemes with bilinear groups. However, the security of this synchronized aggregate scheme was proven under the one-time LRSW assumption in the random oracle model. We give the new security proof for this synchronized aggregate scheme under the 1-MSDH-2 (static) assumption in the random oracle model with little loss of efficiency

A t-out-of-n Redactable Signature Scheme

A redactable signature scheme allows removing parts of a signed message without invalidating the signature. Currently, the need to prove the validity of digital documents issued by governments and enterprises is increasing. However, when disclosing documents, governments and enterprises must remove privacy information concerning individuals. A redactable signature scheme is useful for such a situation. In this paper, we introduce the new notion of the t-out-of-n redactable signature scheme. This scheme has a signer, n redactors, a combiner, and a verifier. The signer designates n redactors and a combiner in advance and generates a signature of a message M. Each redactor decides parts that he or she wants to remove from the message and generates a piece of redaction information. The combiner collects pieces of redaction information from all redactors, extracts parts of the message that more than t redactors want to remove, and generate a redacted message. We consider the one-time redaction model which allows redacting signatures generated by the signer only once. We formalize the one-time redaction t-out-of-n redactable signature scheme, define security, and give a construction using the pairing based aggregate signature scheme in the random oracle model

Solidification Behavior of Iron-Niobium and Iron-Carbon-Niobium Alloys

The undercooling and solidified structure of Fe-Nb binary alloys and Fe-0.1mass%C-Nb ternary alloys were investigated by changing Nb concentration from 0.5 to 6mass%. A glass-encased method was used for achieving high undercooling, in addition to a conventional solidification method. The specimen was furnace-cooled followed by quenching from 1723K or air-cooling from 1473K. As a result, the degree of undercooling in the Fe-Nb alloys solidified by the glass-encased method was higher than that in the specimen solidified by the conventional method, while that in the Fe-0.1mass%C-Nb alloy solidified by the glass-encased method was not so high. The solidified structure in all alloys that were quenched atγ formation temperature has dendritic morphology in spite of δ/γ transformation. The secondary arm spacing of the dendrite became fine with increase in niobium concentration.Materials Science Forum, Volume 475-47