Major physiological adjustments in freezing-tolerant grey tiger longicorn beetle(Xylotrechus rusticus) during overwintering period

1Xylotrechus rusticus （Linnaeus） is one of the most destruc-tive woodborers in northeast China;it damages poplar and is listed as a domestic forestry quarantine pest. Overwintering larvae were collected during October 2012 and March 2013 in Harbin, China, to quantify indi-cators related to the insect’s overwintering strategy and the major cryo-protectants. The supercooling points （SCPs）, which ranged from-14.7＆#176;C to -2.9＆#176;C, were higher than the lethal temperatures of LT50 （-33.64＆#176;C） and LT99 （-40.17＆#176;C） after 24 h exposure. , also the minimum mean daily temperature （-24.5＆#176;C） and mean monthly temperature （-18.0＆#176;C） at the sampling site in January during 2008-2012. Thus, X. rusticus is a typical freezing-tolerant insect. Glycerol serves as a major cryoprotectant for overwintering larvae , because it was the only polyol accumulated during the winter and it also had a significant negative correlation with the SCP （p=0.033, R=0.907）. The glycogen and lipid are major sources of ener-gy and their levels decreased substantially in the middle of overwintering, when glycogen had a significant correlation with the SCP （p= 0.006, R=0.971） whereas the lipid contents did not. Moreover, inter-conversions between glycerol and glycogen, as well as mannose and glycogen, were suggested by their negative correlations. The water content did not change obviously during the winter and was not correlated with the SCP. The free amino acids in the hemolymph and the total protein contents of the bodies of larvae changed significantly during winter, although both had no correlations with the SCP.

Response of root morphology, physiology and endogenous hormones in maize(Zea mays L.) to potassium deficiency

Potassium （K） deficiency is one of the major abiotic stresses which has drastically influenced maize growth and yield around the world. However, the physiological mechanism of K deficiency tolerance is not yet fully understood. To identify the differences of root morphology, physiology and endogenous hormones at different growing stages, two maize inbred lines 90-21-3 （tolerance to K deficiency） and D937 （sensitive to K deficiency） were cultivated in the long-term K fertilizer experimental pool under high potassium （＋K） and low potassium （-K） treatments. The results indicated that the root length, volume and surface area of 90-21-3 were significantly higher than those of D937 under -K treatment at different growing stages. It was noteworthy that the lateral roots of 90-21-3 were dramatically higher than those of D937 at tasselling and flowering stage under-K treatment. Meanwhile, the values of superoxide dismutase （SOD） and oxidizing force of 90-21-3 were apparently higher than those of D937, whereas malondialdehyde （MDA） content of D937 was obviously increased. Compared with ＋K treatment, the indole-3-acetic acid （IAA） content of 90-21-3 was largely increased under-K treatment, whereas it was sharply decreased in D937. On the contrary, abscisic acid （ABA） content of 90-21-3 was slightly increased, but that of D937 was significantly increased. The zeatin riboside （ZR） content of 90-21-3 was significantly decreased, while that of D937 was relatively increased. These results indicated that the endogenous hormones were stimulated in 90-21-3 to adjust lateral root development and to maintain the physiology function thereby alleviating K deficiency.

Mutagenic Effects of BM302:GO112 Induced by Low-Energy Ion Beam Implantation

Mutant strains of GO112 and BM302 with a high 2-keto-L-gulonic acid （2KLG） transformation rate induced by ion beam implantation were separately and combinatorially compared with the original strains GO29 and BM80 to study the mutagenic effects of ion beam implantation. Both the sole GOl12 and mixed BM302：GOl12 demonstrated improved SNDH activity and 2KLG yield compared to the original strains. The mutant combinations of BM302：GOl12 showed a longer stationary phase and higher biomass than BM80：GO29. The mutant BM302 exhibited a stronger capacity to maintain a stable pH environment at mixed fermentation with Gluconobacter oxydans （G. oxydans） for 2KLG transformation and facilitated the growth of G. oxydans compared with the original strain BM80. The promotive capacity to L-sorbosone dehydrogenase （L-SNDH） from the supernate of BM302 was 1.6-fold higher than that of BM80. Genes encoded SNDH in GO29 and GOl12 were amplified and sequenced, and mutations including three transitions （CG →TA, CG →TA, GC → AT） and one transversion （AT→ TA） were confirmed from GO29 to GOl12. The corresponding amino acid was changed as Leu →Phe, Arg → Gln and Asn → Lys.

Measurement of the exercising blood flow during rhythmical muscle contractions assessed by Doppler ultrasound:Methodological considerations

Given the recent technological developments, ultra-sound Doppler can provide valuable measurements of arterial blood flow with high temporal resolution. In a clinical setting, measurements of hemodynamics is used to monitor, diagnose and manage changes in blood velocity profile for cardiac valve disease, relatively large vessel stenosis and other cardiovascular diseases. In health science and preventive medicine for cardiovascular disease with exercise therapy, evaluation of cardiac and vascular function is a useful indicator not only at rest but also during exercise, leading to improved exercise tolerance as well as physical activity. During exercise, the increase in oxygen uptake (calculated as product of arterial blood flow to the exercising limb and the arteriovenous oxygen difference) is directly proportional to the work performed. The increased oxygen demand is met through a central mechanism, an increase in cardiac output and blood pressure, as well as a peripheral mechanism, an increase in vascular conductance and oxygen extraction (major part in the whole exercising muscles) from the blood. Therefore, the determination of the local blood flow dynamics (potential oxygen supply) feeding to rhythmic muscle contractions can contribute to the understanding of the factors limiting the work capacity including, for instance the muscle metabolism, substance utilization and vasodilatation in the exercising muscle. Using non-invasive measures of pulsed Doppler ultrasound the validity of evaluating blood velocity/flow in the fore- arm or lower limb conduit artery feeding to the mus- cle is demonstrated during rhythmic muscle exercise;however the exercising blood velocity profile (fast Fourier transformation) due to muscle contractions is always seen as a physiological variability or fluctuations in the magnitude in blood velocity due to the spontaneous muscle contraction and relaxation induced changes in force curve intensity. Considering the above mentioned variation in blood velocity in relation to muscle contractions may provide valuable information for evaluating the blood flow dynamics during exercise. This review presents the methodological concept that underlines the methodological considerations for determining the exercising blood velocity/flow in the limb conduit artery in relation the exercise model of dynamic leg exercise assessed by pulsed Doppler ultrasonography.