Direct observation of bear myrmecophagy: Relationship between bears’ feeding habits and ant phenology

We studied the ant-feeding behavior of Asiatic black bears (Ursus thibetanus) through direct observation in the Ashio area of Japan. We recorded the bears’ “time foraging per ant nest” (TPN), documented the seasonal occurrence of ants in their scats, estimated phenological changes in caste composition of the nests of two abundant ant species (Lasius flavus and L. hayashi), and calculated the nutritional composition of queens, males, workers, queen pupae, and non-queen pupae of both species. We addressed two main hypotheses: (1) ant-nest phenology, especially the availability of pupae, affects bears’ myrmecophagy level; and (2) TPN changes according to the caste composition of ant nests. Bears in the Ashio area consumed more ants than in previous studies elsewhere in Japan, with consumption peaking in early July. The availability of pupae may trigger ant feeding by bears. And, because queen pupae were heavier than members of other castes, calories per individual were higher. TPN varied during the study period (late June–early August). There was a negative relationship between frequency of occurrence of pupae in ant nests and TPN; because pupae cannot move by themselves, bears could consume them effectively and quickly. Thus, bears may change their ant-foraging behavior (especially TPN) based on ant nest composition.     

Seasonal changes and altitudinal variation in deer fecal pellet decay

Surveying dung pellet groups to estimate population size requires knowledge of the dung decay rates in different environmental conditions. We evaluated seasonal and elevational differences in the decay rates of fresh deer pellets in the Ashio–Nikko Mountains, Japan. At each of four sites (1,500, 1,200, 900, and 600 m above sea level), we set out four replicates of 50 fresh deer pellets each month from September 2008 to August 2009. Dung pellet groups were evaluated after 24 h and again monthly. We also monitored the dung beetle fauna monthly using pitfall traps. Dung beetle activity was positively correlated with temperature, and the rate of dung decay was strongly correlated with dung beetle dry weight. Decay was most rapid during summer and at lower altitudes; pellets set out during winter did not decay until the following spring. Resource managers who use dung surveys to estimate population sizes in mountainous regions should consider the decay rates at different altitudes.     

Estimate of the seed shadow created by the Asiatic black bear Ursus thibetanus and its characteristics as a seed disperser in Japanese cool‐temperate forest

We estimated the seed shadow created by the Asiatic black bear Ursus thibetanus in order to evaluate the bears effectiveness as a seed disperser. We combined data from bear movements, determined by GPS telemetry, with data from gut retention time (GRT). We estimated plant seed shadows in two ways: from direct movement data to give the actual seed shadow (ASS), and from cumulative movement data to give the potential seed shadow (PSS). The purpose of this study was to answer the following questions: (1) does GRT differ between seasons or in the size of contents? (2) Does seed shadow vary among sex, seasons, estimation method (ASS or PSS), and years? (3) Does the masting affect seed shadows? There were no differences in median GRT among seasons or seed dimensions. Combining these data, the seed shadows produced by long GRT (median; 15.2–19.7 hours, maximum; 44.0 hours) and large daily movements suggest that the bears effectively move 40% of the seeds they consume to a distance greater than 500 m from the parent tree and can potentially move the seeds up to a maximum distance of more than 22 000 m from the parent tree. The results also indicate that bears make complex seed shadows caused by multiple defecations and long periods of daily movement. In summary, PSS did not differ between sexes, but PSS can be expected to be larger in autumn than in summer of each year. ASS, however, can be expected to be larger in males than females, and to be larger in autumn than in summer. ASS may become especially large during a poor masting year as compared to good masting years. These results indicate that bears are potentially more effective seed dispersers during years of poor fruit production in autumn. The bears have longer seed shadows than other seed disperser and consequently may play a unique role in the maintenance and renewal of forest ecosystem.     

Effect of mast production on home range use of Japanese black bears

Although bears may expand their home ranges in times of low food availability, it is unclear what mechanisms directly affect home range extension in times of low mast production in Japanese forests. To clarify the relationship between home range utilization by Japanese black bears (Ursus thibetanus) and abundance and distribution of mast production, we collected data on habitat use from 13 bears (6 M and 7 F) fitted with Global Positioning System (GPS) collars equipped with activity sensors in the Ashio-Nikko Mountains on the eastern part of Honshu Island, Japan, during 2006–2008. We also collected data on mast production by 5 Fagaceae species. We categorized each fall as either poor (2006) or relatively-good (2007 and 2008) based on mast production. Bears used small patches in their large home ranges and the distances between core areas increased in the fall of 2006, when the mast of Japanese oak (Quercus crispula) were poorly distributed. Our findings suggest that localized patches of Japanese oak are the staple food for bears in our study area, even in poor mast years. However, in the fall of 2006, we also found that bears moved to lower elevations, relative to 2007 and 2008, in search of alternative foods (e.g., Konara oak [Q. serrata] and Japanese chestnut [Castanea crenata]), which were mostly at lower elevations and produced mast consistently over the study period. Our results suggest that dispersion and elevational distribution of mast-producing trees affect bear habitat use in fall, as well as amount of mast. © 2011 The Wildlife Society.     

Metabolic adaptation to flooding stress in upland and lowland rice seedlings

Ability of metabolic adaptation in upland and lowland rice (Oryza sativa L.) seedlings to flooding stress was compared. Flooding stress increased alcohol dehydrogenase (ADH) activity and ethanol concentration in shoots and roots of the upland and lowland rice seedlings. The difference in ADH activity and ethanol concentration in shoots between the upland and lowland rice was not apparent. However, both ADH activity and ethanol concentration in roots of the lowland rice were 2-fold greater than those in roots of the upland rice, suggesting that flooding-induction of ethanolic fermentation in lowland rice roots may be significantly greater than that in the upland rice roots. Since flooding often causes the anaerobic conditions in rooting zone than aerial part of plants and ethanolic fermentation is essential to survive in the anaerobic conditions, the ability of metabolic adaptation in lowland rice seedlings to flooding stress may be greater than that in upland rice seedlings.     

Physiological responses of simulated karate sparring matches in young men and boys

The purpose of this study was to investigate the duration of each series of offensive and defensive techniques and the cardiovascular, metabolic, and perceptual responses during 2- and 3-minute bouts of simulated karate sparring. Six young men (age, 18-20 years) and 6 boys (age, 16-17 years) participated in this study. We formed 3 pairs of men and 3 pairs of boys to create a demanding competitive environment. After a rest period, each pair performed a 2-minute bout of sparring, sat quietly for 60 minutes, and then performed 3-minute bout of sparring. We measured oxygen uptake (Vo2), heart rate (HR), and blood lactate responses and ascertained the rate of perceived exertion (RPE) and energy expenditure (EE) during these sparring bouts. The ventilatory threshold was estimated from ventilatory equivalent and Vo2 obtained during the treadmill test. The duration of each series of offensive and defensive techniques was videotaped. During the 2- and 3-minute bouts of sparring, the duration of longest series of offensive and/or defensive combination techniques performed were 2.1 +/- 1.0 and 1.8 +/- 0.4 seconds, respectively; the mean total times of performing offensive and defensive techniques were 13.3 +/- 3.3 and 19.4 +/- 5.5 seconds, respectively. The mean oxygen uptake (Vo2), the percentage of maximum oxygen uptake (%Vo2max), HR, percentage of maximum HR, RPE, and EE for a 3-minute bout of sparring were significantly higher than for a 2-minute bout of sparring. The mean %Vo2max values for these bouts of sparring were below the ventilatory threshold. It is recommended that karate practitioners perform more specific weight training, plyometric exercises, and interval training to increase the ability to buffer acid muscle and blood concentrations and to build lean body mass, strength, and power to develop the specific motor skills required in sparring.     

KMI-358 and KMI-370, highly potent and small-sized BACE1 inhibitors containing phenylnorstatine

Recently, we reported a novel substrate-based octapeptide BACE1 inhibitor KMI-008 containing hydroxymethylcarbonyl (HMC) isostere as a transition-state mimic. Using KMI-008 as a lead compound, a small-sized and highly potent BACE1 inhibitor KMI-370 (IC(50)=3.4 nM) was designed and synthesized.     

A Galpha subunit controls zoospore motility and virulence in the potato late blight pathogen Phytophthora infestans

The heterotrimeric G-protein pathway is a ubiquitous eukaryotic signalling module that is known to regulate growth and differentiation in many plant pathogens. We previously identified Pigpa1, a gene encoding a G-protein alpha subunit from the potato late blight pathogen Phytophthora infestans. P. infestans belongs to the class oomycetes, a group of organisms in which signal transduction processes have not yet been studied at the molecular level. To elucidate the function of Pigpa1, PiGPA1-deficient mutants were obtained by homology-dependent gene silencing. The Pigpa1-silenced mutants produced zoospores that turned six to eight times more frequently, causing them to swim only short distances compared with wild type. Attraction to the surface, a phenomenon known as negative geotaxis, was impaired in the mutant zoospores, as well as autoaggregation and chemotaxis towards glutamic and aspartic acid. Zoospore production was reduced by 20-45% in different Pigpa1-silenced mutants. Transformants expressing constitutively active forms of PiGPA1, containing amino acid substitutions (R177H and Q203L), showed no obvious phenotypic differences from the wild-type strain. Infection efficiencies on potato leaves ranged from 3% to 14% in the Pigpa1-silenced mutants, compared with 77% in wild type, showing that virulence is severely impaired. The results prove that PiGPA1 is crucial for zoospore motility and for pathogenicity in an important oomycete plant pathogen.     

Nutrient intake of highly competitive male and female collegiate karate players

Nutrient intake of 29 male (M Group) and 16 female (F Group) highly competitive collegiate karate players were compared. The results were also compared with the daily energy expenditure (DEE), Japanese recommended dietary allowances (RDAs) or adequate dietary intakes (ADIs). Dietary information was collected using a 3-weekday diet record. Although the M Group showed significantly higher mean %RDAs or %ADIs in iron, vitamin B1, phosphorus, magnesium, and sodium than the F Group, many of the mean %RDAs or %ADIs were below RDAs or ADIs in both groups. The subjects who skipped meals tended to show lower mean %DEE, Japanese %RDAs or %ADIs in minerals and vitamins than the subjects who did not skip in both M and F Groups. The consumption of green and other vegetables and milk and dairy products in both M and F Groups were low. It is concluded that the male and female highly competitive karate players studied in the present study may be at risk of sub-optimal nutrient intake, which increases the potential for nutrient deficiency. The subjects were advised not to skip meals, and to consume a balanced high-carbohydrate, moderate-protein, low-fat diet with increasing green and other vegetables and milk and dairy products to increase mineral, vitamin and dietary fiber intakes.