Factors affecting the infiltration capacity in bamboo groves

To determine the effects of the characteristics of litter and surface soil on the infiltration capacity in bamboo groves, infiltration rates were measured on a plot-scale using an oscillating-nozzle rainfall simulator at seven Moso bamboo (Phyllostachys pubescens) sites and one Madake (P. bambusoides) site in Japan. The maximum final infiltration rate (FIR_max), which was defined in this study as the infiltration capacity, was calculated, and the correlation between FIR_max and earth surface properties was analyzed. The FIR_max ranged from 9 to 308?mm?h^?1, showing little correlation with litter as surface cover, and a weak correlation with bulk density (0.3–0.9?g?cm^?3) and organic matter content (10.4–45.9%). These results suggest that the bulk density and organic matter content of surface soil, rather than surface cover, can be the controlling factors of infiltration capacity in bamboo groves. The bulk density of surface soil correlated significantly with the soil organic matter content, represented by bamboo rhizomes, suggesting that the infiltration capacity can increase with the amount of root networks present, related to macropore formation. The stand density showed a weak positive correlation, although not significant, with the soil organic matter content and a positive correlation with FIR_max. Thus, the infiltration capacity of bamboo groves can increase as the stand density of culms and bamboo rhizomes increase.     

Abundance and use of cavity trees at the tree- and stand-levels in natural and plantation forests in Hokkaido, Japan

The conservation of cavity trees in plantations is important for maintaining biodiversity because cavity trees are one of the forest attributes most strongly affected by forestry operations. We surveyed the occurrence of cavities at the tree-level and the abundance of cavity trees and the number of uses by secondary cavity users at the stand-level in natural and conifer plantation forests in Hokkaido, Japan. We classified cavities into two types by their formation processes: excavated and non-excavated. Excavated cavities were more common in dead trees than in live trees. Non-excavated cavities showed high occurrence in dead and live broad-leaved trees. The abundance of non-excavated cavity trees was two times greater than that of excavated cavity trees in natural forests, but, in plantations, excavated cavity trees were dominant. The abundance of non-excavated cavity trees was lower in thinned plantations than in not-thinned plantations. The number of cavity uses increased with the number of cavity trees, indicating the importance of maintaining cavity trees. Conifer plantations are established by removing native broad-leaved trees, which results in a lower abundance of non-excavated cavity trees in these locations. The conservation of broad-leaved trees is important for maintaining the current and future resource of non-excavated cavity trees in plantation forests, as is the conservation of dead trees, which showed a high occurrence of excavated cavities.     

Transition of Historical Control Data for High Incidence Tumors in F344 Rats

Historical control data of tumor incidence were collected from the control groups (215 animals of each sex) in four recent carcinogenicity studies that were started between 2005 to 2009 (terminally sacrificed between 2007 and 2011) at BoZo Research Center Inc. (Gotemba, Shizuoka, Japan) using Fischer 344 rats (F344/DuCrlCrlj). These data were compared to the previous historical control data (from 1990 to 2004, previously reported) in the same facility. In the results, the incidence of C-cell adenoma in the thyroid tended to increase in both sexes in recent years (30.8% for males and 24.4% for females in 2005-2009) as compared with the previous data (17.4% and 20.1% for males and 11.5% and 11.8% for females in 1990–1999 and 2000–2004, respectively). In addition, the incidences of pancreatic islet cell adenoma in males and uterine adenocarcinoma tended to increase from around 2000 and remained high in recent years (incidences of islet cell adenoma in males of 10.5%, 17.1% and 20.5% in 1990–1999, 2000–2004 and 2005–2009; incidences of uterine adenocarcinoma of 3.3%, 12.0% and 13.5% in 1990–1999, 2000–2004 and 2005–2009, respectively). There was no apparent difference in the incidence of other tumors.     

A Case of Metastatic Adrenocortical Carcinoma Diagnosed with Steroidogenic Factor-1 in a Sprague-Dawley Rat

This report describes the morphological and immunohistochemical characteristics of an adrenocortical carcinoma with distant metastasis in a Sprague-Dawley rat. Macroscopically, a single large mass was observed in the adrenal gland, and multiple nodules were noted in the lung, liver and thyroid. Histologically, the adrenal tumor consisted of a solid growth of eosinophilic round cells with nuclear atypia. Vascular invasion was present, and multiple metastatic lesions were also observed in the lungs, liver, and mediastinal lymph nodes. Immunohistochemically, the nuclei of these tumor cells were positive for Steroidogenic Factor-1 (SF-1). In the thyroid, tumor cells histologically resembling adrenal cells were immunohistochemically negative for SF-1 but positive for calcitonin; thus the lesion was diagnosed as thyroid C-cell carcinoma. From these results, the present case was diagnosed as adrenocortical carcinoma with distant metastases. SF-1 could be a valuable marker for the differential diagnosis of adrenocortical tumors versus other endocrine tumors such as C-cell carcinoma.     

N -Methyl- N -nitrosourea-induced Renal Tumors in Rats: Immunohistochemical Comparison to Human Wilms Tumors

N-Methyl-N-nitrosourea (MNU)-induced renal tumors in rats and Wilms tumors in humans were compared. Renal mesenchymal tumors (RMTs) and nephroblastomas (blastemal and epithelial components) in female Lewis rats treated with a single intraperitoneal injection of 50 mg/kg MNU at birth and Wilms tumors (blastemal, epithelial and mesenchymal components) in humans were analyzed for the expression of pancytokeratin (CK), vimentin, p63, α-smooth muscle actin (SMA), desmin, S-100, CD57, CD117/c-kit, Wilms tumor 1 protein (WT1) and β-catenin. The mesenchymal components of rat RMTs and human Wilms tumors expressed vimentin, SMA and β-catenin. The blastemal components of rat nephroblastomas and human Wilms tumors expressed vimentin, CD117/c-kit and β-catenin. The epithelial components of rat nephroblastomas and human Wilms tumors expressed vimentin and β-catenin. WT1 was expressed in different cellular components of rat tumors as compared with human Wilms tumors; the expression was seen in mesenchymal tumors and blastemal components of nephroblastomas in rats and epithelial components in human Wilms tumors. CK, p63 and CD57 were not expressed in rat RMTs or nephroblastomas, while CK and WT1 were expressed in epithelial components and CD57 was expressed in blastemal and epithelial components of human Wilms tumors. Rat and human tumors were universally negative for the expression of desmin and S-100. The immunohistochemical characteristics of rat renal tumors and human Wilms tumors may provide valuable information on the differences in renal oncogenesis and biology between the two species.     

Changes in the concentrations of acrylamide, selected odorants, and catechins caused by roasting of green tea

This research aims to optimize roasted green tea (Houjicha) processing by using roasting treatments to achieve acrylamide mitigation without compromising the quality. 2-Ethyl-3,5-dimethylpyrazine and 2-ethyl-3,6-dimethylpyrazine were identified as potent odorants by aroma extract dilution analysis. In preliminary sensory experiments, the desirable Houjicha flavor was produced in products roasted at 160 degrees C for 30 min and at 180 degrees C for 15 min. Under these conditions, potent odorants were formed at levels adequate for contributing to the Houjicha flavor. Acrylamide amounts in tea infusions were 2.0 and 4.0 microg/L by roasting at 160 degrees C for 30 min and at 180 degrees C for 15 min, respectively. Compared to roasting at 180 degrees C, the degradation of tea catechins was suppressed by roasting at 160 degrees C. Hence, roasting at 160 degrees C for is recommended for Houjicha processing for acrylamide mitigation, formation of potent odorants, and suppression of degradation of tea catechins.     

Turbid water induces refuge behaviour of a commercially important ayu: A field experiment for interstream movement using multiple artificial streams

Riverine systems are inherently dendritic in nature, and turbid water may not necessarily flow equally throughout an entire catchment. Tributaries have the potential to serve as refugia from temporarily turbid water in the main stem. As ayu (Plecoglossus altivelis) are one of the important species for the inland fisheries industry and recreational fishing, their behaviour in a branched river network is a primary concern. We released ayu with radio‐transmitting tags into two experimental streams that joined at a downstream pool. Turbid water was released into one of the streams, and we identified whether avoidance movement of ayu between the two experimental streams was triggered by flowing turbid water. The suspended solid concentration elevated rapidly after adding the turbid water and was maintained at more than 400 mg/L for 3 hr. Avoidance movement of ayu was triggered when the suspended solid concentration exceeded approximately 200 mg/L. Then, most ayu moved from the turbid stream to the nonturbid one, leading to a difference in ayu density between the two streams. Therefore, we demonstrated that turbid water induced interstream movement of a commercially important ayu as refuge behaviour, suggesting that river connectivity is important for the persistence of the ayu.     

Comparison of morphological and DNA-based techniques for stomach content analyses in juvenile chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis>: a case study on diet richness of juvenile fishes

To identify the stomach contents of marine organisms, morphological observations are commonly conducted. However, the results obtained by this traditional method are frequently biased, as it is difficult to detect partially digested, soft-bodied organisms. To resolve this, recent studies have used DNA-based (DNA barcoding) analyses to examine the diet breadth of marine organisms. Here, we compared the prey richness of juvenile fishes using morphological observations and DNA-based analyses, with a focus on juvenile chum salmon Oncorhynchus keta. A higher number of prey taxa were successfully identified using DNA-based analyses than morphological observations. However, we also noticed several shortcomings of the DNA-based analyses, as reported in other diet-analysis studies that used molecular techniques. For example, the degree of digestion among prey taxa might have resulted in differential sensitivity to DNA detection. Additionally, several prey taxa could not be precisely identified, as the sequence data for some of the targeted organismal groups are unavailable in public gene databases. Remarkably, it is also possible that DNA-based analyses detected secondary prey, and therefore, the richness of prey taxa was likely overestimated. Thus, dietary analyses of juvenile fishes need to be carefully conducted, considering the respective advantages and disadvantages of DNA-based and morphological techniques.     

Quantifying growth in maricultured corals using photogrammetry

In coral mariculture, growth is one of the most common ways to track success. However, numerous methods of monitoring coral growth make comparative studies challenging. A literature review of 39 studies from 1982 to 2017 indicated that the most predominant non‐invasive methods used were linear and areal measurement and these were evaluated for their accuracy using nursery‐reared corals. The monthly change in linear and areal growth rates of six coral species (n = 215), Pocillopora acuta, Hydnophora rigida, Merulina ampliata, Podabacia crustacea, Echinopora lamellosa and Platygyra sinensis were measured via photogrammetry. We tested whether the planar area of coral colonies can be estimated using three geometric formulas of linear measurements. Based on the literature review, the six types of measurement methods were namely linear, volume, weight, area, count of polyps/branches and calcification, in decreasing order of application. Our results showed that the change in area calculated by geometric mean diameter (GMD) formulas provided the most accurate estimation among the three formulas and was strongly correlated with planar area (R² ≥ .60; p < .05) for all coral species, except E. lamellosa and Pl. sinensis. However, our findings suggest that it is not ideal to use geometric formulas to estimate the change in area. Instead, we posit that areal photogrammetry represents the simplest yet accurate non‐invasive method for rapid monitoring of extensive areas of corals in situ. Lastly, we discuss the recommendations and limitations for areal photogrammetry.     

<Emphasis Type="Italic">Pseudomonas syringae</Emphasis> pv. <Emphasis Type="Italic">alliifistulosi</Emphasis> pv. nov., the causal agent of bacterial leaf spot of onions

In 1972, bacterial leaf spot of onion (BLSO) was first recorded in Japan by Goto. The pathogen was considered as a pathovar of Pseudomonas syringae specifically causing disease on onion and Welsh onion, but it has not been taxonomically investigated in detail. In 2012 and 2014, a disease suspected as BLSO re-emerged on onion in Shizuoka and Hyogo Prefectures, Japan, respectively. A pathogenic bacterium isolated from the infected onions was thought to be the BLSO agent after preliminary examinations. Strains isolated from BLSO in 1969, 1986, 1987, 2012 and 2014 were characterized and compared with the causal agent of bacterial blight of leek (P. syringae pv. porri), which causes similar symptoms on Allium plants. The result of rep-PCR distinguished the BLSO agent from P. syringae pv. porri. Multilocus sequence analysis on housekeeping genes and hrp genes encoding the type-III secretion system revealed that the strains of the BLSO agent clustered independently of P. syringae pv. porri. The BLSO agent and P. syringae pv. porri also differed in utilization of erythritol, dl-homoserine, glutaric acid and other bacteriological characteristics and caused different reactions on onion, Welsh onions, chives, shallot, rakkyo, leek, garlic and Chinese chive. Thus, the BLSO agent clearly differs from P. syringae pv. porri and is considered to be a new pathovar of P. syringae. The name P. syringae pv. alliifistulosi is proposed with pathotype strain ICMP3414.