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Freeze-thaw events can affect plant hydraulics by inducing embolism. This study analyzed the effect of temperature during the freezing process on hydraulic conductivity and ultrasonic emissions (UE). Stems of 10 angiosperms were dehydrated to a water potential at 12% percentage loss of hydraulic conductivity (PLC) and exposed to freeze-thaw cycles. The minimal temperature of the frost cycle correlated positively with induced PLC, whereby species with wider conduits (hydraulic diameter) showed higher freeze-thaw-induced PLC. Ultrasonic activity started with the onset of freezing and increased with decreasing subzero temperatures, whereas no UE were recorded during thawing. The temperature at which 50% of UE were reached varied between -9.1°C and -31.0°C across species. These findings indicate that temperatures during freezing are of relevance for bubble formation and air seeding. We suggest that species-specific cavitation thresholds are reached during freezing due to the temperature-dependent decrease of water potential in the ice, while bubble expansion and the resulting PLC occur during thawing. UE analysis can be used to monitor the cavitation process and estimate freeze-thaw-induced PLC.

Seasonal changes in the accumulation of soluble sugars in extracellular freezing cortical parenchyma cells and deep supercooling xylem parenchyma cells in Japanese white birch (Betula platyphylla var. japonica) were compared to identify the effects of soluble sugars on the mechanism of deep supercooling, which keeps the liquid state of water in cells under extremely low temperatures for long periods. Soluble sugars in both tissues were analyzed by high-performance liquid chromatography (HPLC), and the concentrations of sugars in cells were estimated by histological observation of occupancy rates of parenchyma cells in each tissue. Relative and equilibrium melting points of parenchyma cells were measured by differential thermal analysis and cryoscanning electron microscopy, respectively. In both xylem and cortical parenchyma cells, amounts of sucrose, raffinose and stachyose increased in winter, but amounts of fructose and glucose exhibited little change throughout the entire year. In addition, no sugars were found to be specific for either tissue. Combined results of HPLC analyses, histological observation and melting point analyses confirmed that the concentration of sugars was much higher in xylem cells than in cortical cells. It is thought that the higher concentration of soluble sugars in xylem cells may contribute to facilitation of deep supercooling in xylem cells by depressing the nucleation temperature.

Abstract Low-temperature adaptation in rice is mediated by the ability of a genotype to tolerate chilling temperatures. A genetic locus on chromosome 11 was analysed for chilling tolerance at the plumule stage in rice. The tolerant allele of A58, a japonica landrace in Japan, was inherited as a recessive gene (ctp-1A58), whereas the susceptible alleles from wild rice (Ctp-1W107) and modern variety (Ctp-1HY) were the dominant genes. Another recessive tolerant allele (ctp-1Silewah) was found in a tropical japonica variety (Silewah). Fine-mapping revealed that a candidate gene for the ctp-1 locus encoded a protein similar to the nucleotide-binding domain and leucine-rich repeat (NLR) protein, in which frameshift mutation by a 73 bp-deletion might confer chilling tolerance in ctp-1A58. Analysis of near-isogenic lines demonstrated that ctp-1A58 imparted tolerance effects only at severe chilling temperatures of 0.5 °C and 2 °C, both at plumule and seedling stages. Chilling acclimation treatments at a wide range of temperatures (8 °C–16 °C) for 72 h concealed the susceptible phenotype of Ctp-1W107 and Ctp-1HY. Furthermore, short-term acclimation treatment of 12 h at 8 °C was enough to be fully acclimated. These results suggest that the NLR gene induces a susceptible response upon exposure to severe chilling stress, however, another interacting gene(s) for acclimation response could suppress the maladaptive phenotype caused by the Ctp-1 allele. This study provides new insights for the adaptation and breeding of rice in a low-temperature environment. This paper showed that a recessive gene (ctp-1) conferred tolerance to severe chilling stress and its candidate gene was nucleotide-binding domain and leucine-rich repeat (NLR) gene, known as disease resistance gene. The role of acclimation response, which enhances chilling tolerance by pre-exposure to mild stress temperature before severe stress, has been mostly ignored in rice breeding; however, we demonstrated that gene(s) other than the intrinsic tolerance gene (the ctp-1 locus) could contribute to improvement of chilling tolerance.

Ultrasonic acoustic emission (UAE) methods have been applied for the detection of freeze–thaw-induced embolism formation in water conduits of tree species. Until now, however, the exact source(s) of UAE has not been identified especially in angiosperm species, in which xylem tissues are composed of diverse types of cells. In this study, UAE was recorded from excised branches of walnut (Juglans regia cv. Franquette) during freeze–thaw cycles, and attempts were made to characterize UAEs generated by cavitation events leading to embolism formation according to their properties. During freeze–thaw cycles, a large number of UAEs were generated from the sample segments. However, the cumulative numbers of total UAE during freeze–thawing were not correlated with the percentage loss of hydraulic conductivity after thawing, suggesting that the sources of UAE were not only cavitation leading to embolism formation in vessels. Among the UAEs, cumulative numbers of UAEs with absolute energy >10.0 fJ strongly correlated with the increase in percentage loss of hydraulic conductivity. The high absolute energy of the UAEs might reflect the formation of large bubbles in the large lumen of vessels. Therefore, UAEs generated by cavitation events in vessels during freeze–thawing might be distinguished from other signals according to their magnitudes of absolute energy. On the other hand, the freezing of xylem parenchyma cells was followed by a certain number of UAEs. These results indicate the possibility that UAE methods can be applied to the detection of both freeze–thaw-induced embolism and supercooling breakdown in parenchyma cells in xylem.

Castleman’s disease was first reported in 1954 by Castleman et al. and identified as an uncommon lymphoproliferative disorder. In most cases, Castleman’s diseases are detected in the chest, head, and neck. A 71-year-old man was referred to our hospital due to a retroperitoneal tumor in the para-aortic area by computed tomography (CT). Positron emission tomography-CT revealed an uptake in this tumor, suggesting malignant diseases. Laparoscopic tumorectomy was performed, and the pathological diagnosis was Castleman’s disease, hyaline vascular type. No evidence of recurrence was observed 20 months after surgery. We herein report a rare case of retroperitoneal Castleman’s disease.

IgG4-related disease is diagnosed when both the elevation of the serum IgG4 level and invasion of IgG4-positive interstitial cells and sclerosis to a tumor are noted. Some cases have demonstrated malignant disease. In the head and neck lesion in particular, IgG4-producing mucosa-associated lymphoid tissue (MALT) lymphoma has arisen during the treatment of IgG4-related disease. We herein report the first case of IgG4-producing MALT lymphoma during the treatment of IgG4-related disease in the renal hilum. A 79-year-old man was being followed for autoimmune pancreatitis and IgG4-related sclerosing cholangitis. During follow-up, magnetic resonance cholangiopancreatography detected a mass in the renal hilum, so he was referred to our department for a further examination. Positron emission tomography-computed tomography detected a standard uptake of 9.7, and the tumor size was gradually increasing. Due to these findings, laparoscopic nephro-ureterectomy was performed. A pathological examination revealed IgG4-producing marginal zone B cell lymphoma. We herein report a rare case of IgG4-producing B cell lymphoma in the renal hilum.

Xylem parenchyma cells (XPCs) in trees adapt to subzero temperatures by deep supercooling. Our previous study indicated the possibility of the presence of diverse kinds of supercooling-facilitating (SCF; anti-ice nucleation) substances in XPCs of katsura tree (Cercidiphyllum japonicum), all of which might have an important role in deep supercooling of XPCs. In the previous study, a few kinds of SCF flavonol glycosides were identified. Thus, in the present study, we tried to identify other kinds of SCF substances in XPCs of katsura tree. SCF substances were purified from xylem extracts by silica gel column chromatography and Sephadex LH-20 column chromatography. Then, four SCF substances isolated were identified by UV, mass and nuclear magnetic resonance analyses. The results showed that the four kinds of hydrolyzable gallotannins, 2,2', 5-tri-0-galloyl-α,β-D-hamamelose (trigalloyl Ham or kurigalin), 1,2,6-tri-O-galloyl-β-D-glucopyranoside (trigalloyl Glc), 1,2,3,6-tetra-O-galloyl-β-D-glucopyranoside (tetragalloyl Glc) and 1,2,3,4,6-penta-O-galloyl-β-D-glucopyranoside (pentagalloyl Glc), in XPCs exhibited supercooling capabilities in the range of 1.5-4.5°C, at a concentration of 1 mg mL⁻¹. These SCF substances, including flavonol glycosides and hydrolyzable gallotannins, may contribute to the supercooling in XPCs of katsura tree.

It has been accepted that xylem ray parenchyma cells (XRPCs) in hardwood species respond to subfreezing temperatures either by deep supercooling or by extracellular freezing. Present study by cryo-scanning electron microscopy examined the freezing responses of XRPCs in five boreal hardwoods: Salix sachalinensis Fr. Schmit, Populus sieboldii Miq., Betula platyphylla Sukat. var japonica Hara, Betula pubescens Ehrh., and red osier dogwood (Cornus sericea), in which XRPCs have been reported to respond by extracellular freezing. Cryo-scanning electron microscopy observations revealed that slow cooling of xylem to -80°C resulted in intracellular freezing in the majority of XRPCs in S. sachalinensis, an indication that these XRPCs had been deep supercooled. In contrast, in the majority of XRPCs in P. sieboldii, B. platyphylla, B. pubescens, and red osier dogwood, slow cooling to -80°C produced slight cytorrhysis without clear evidence of intracellular freezing, suggesting that these XRPCs might respond by extracellular freezing. In these XRPCs exhibited putative extracellular freezing; however, deep etching revealed the apparent formation of intracellular ice crystals in restricted local areas. To confirm the occurrence of intracellular freezing, we rewarmed these XRPCs after cooling and observed very large intracellular ice crystals as a result of the recrystallization. Thus, the XRPCs in all the boreal hardwoods that we examined responded by deep supercooling that was accompanied with incomplete desiccation. From these results, it seems possible that limitations to the deepsupercooling ability of XRPCs might be a limiting factor for adaptation of hardwoods to cold climates.

Primary penile cancer is a rare disease. Higher incidence rates occur in underdeveloped countries. Many studies have suggested an association between human papillomavirus (HPV) infection and penile cancer. Although HPV can affect the squamous epithelium of the male genitalia similarly to the female genital tract, the association between penile cancer and HPV remains unclear. In the present study, the HPV gene expression was examined in penile cancer tissue using in situ hybridization (ISH). The present study included 41 cases in which penectomy was performed and 3 cases in which tumor resection was performed to treat pathologically-diagnosed penile cancer at Yokohama City University Medical Center, and its 7 affiliated hospitals between April 1990 and March 2010. The penile cancer tissue was subjected to an ISH analysis, and the clinicopathological features and prognosis were investigated. A total of 5/44 cases (11.4%) showed the expression of high-risk HPV. None of the patients showed the expression of low-risk HPV. The associations between the expression of high-risk HPV, and age, tumor location, tumor size, T stage, pathological differentiation, nuclear grade, Broder's classification, pattern of invasion, Y-K grade, vascular invasion, lymphoid invasion, koilocytosis and lymph-node metastasis were then examined. Patients with a well-differentiated status (P=0.044) and Broder's Grade 1 (P=0.019) showed a significantly lower rate of HPV positivity. The HPV expression was not significantly associated with cancer specific survival (P=0.932). ISH using INFORM HPV III does not detect the HPV genotype, this method is easy to employ and may be useful for the diagnosis of penile cancer tissue, similarly to cervical cancer.