Isolation of lactic acid bacteria from pao cai, a Chinese traditional fermented vegetable, with inhibitory activity against Salmonella associated with fresh-cut apple, using a modelling study

AIMS

To isolate lactic acid bacteria (LAB) from pao cai, a Chinese traditional fermented vegetable, with outstanding inhibitory activity against Salmonella inoculated on fresh-cut apple, using a modelling method.

METHODS AND RESULTS

Four kinds of pao cai were selected. A total of 122 isolates exhibited typical LAB characteristics: Gram-positive and catalase negative, among which 104 (85·24%) colonies showed antibacterial activity against Salmonella by the well diffusion assay. Four colonies showing maximum antibacterial radius against Salmonella were selected to co-inoculate with Salmonella on fresh-cut apple and stored at 10°C, further identified as three strains of Lactobacillus plantarum and one strain of Lactobacillus brevis by 16s rRNA gene sequence analysis. The modified Gompertz model was employed to analyse the growth of the micro-organisms on apple wedges. Two of the four selected strains showed antagonistic activity against Salmonella on fresh-cut apple, one of which, RD1, exhibited best inhibitory activity (Salmonella were greatly inhibited when co-inoculated with RD1 at 10°C at 168 h). No deterioration in odour or appearance of the apple piece was observed by the triangle test when fresh-cut apple was inoculated with RD1.

CONCLUSIONS

The mathematical modelling method is essential to select LAB with outstanding inhibitory activity against Salmonella associated with fresh-cut apple. LAB RD1 holds promise for the preservation of fresh-cut apple.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provided a new method on fresh-cut product preservation. Besides, to make the LAB isolating procedure a more correct one, this study first added the mathematical modelling method to the isolating procedure.

Graphical user interface for yield and dose estimations for cyclotron-produced technetium

The cyclotron-based (100)Mo(p,2n)(99m)Tc reaction has been proposed as an alternative method for solving the shortage of (99m)Tc. With this production method, however, even if highly enriched molybdenum is used, various radioactive and stable isotopes will be produced simultaneously with (99m)Tc. In order to optimize reaction parameters and estimate potential patient doses from radiotracers labeled with cyclotron produced (99m)Tc, the yields for all reaction products must be estimated. Such calculations, however, are extremely complex and time consuming. Therefore, the objective of this study was to design a graphical user interface (GUI) that would automate these calculations, facilitate analysis of the experimental data, and predict dosimetry. The resulting GUI, named Cyclotron production Yields and Dosimetry (CYD), is based on Matlab®. It has three parts providing (a) reaction yield calculations, (b) predictions of gamma emissions and (c) dosimetry estimations. The paper presents the outline of the GUI, lists the parameters that must be provided by the user, discusses the details of calculations and provides examples of the results. Our initial experience shows that the proposed GUI allows the user to very efficiently calculate the yields of reaction products and analyze gamma spectroscopy data. However, it is expected that the main advantage of this GUI will be at the later clinical stage when entering reaction parameters will allow the user to predict production yields and estimate radiation doses to patients for each particular cyclotron run.

Antiemesis effect and brain fMRI response of gastric electrical stimulation with different parameters in dogs

BACKGROUND

The aims of this study were to investigate the effect of gastric electrical stimulation (GES) with different parameters on emesis induced by apomorphine, and possible center mechanisms by brain functional magnetic resonance imaging (fMRI).

METHODS

Six dogs implanted with electrodes on gastric serosa were used in this study. Part 1: Apomorphine was injected in the control session and GES sessions. GESs with different parameters were applied in GES session. Gastric slow waves and emesis and behaviors suggestive of nausea were recorded in each session. Part 2: Each dog was anesthetized and given GESs with different parameters or sham stimulation for 15 min after baseline (5 min), respectively. The location of cerebral activation induced by GES was investigated by fMRI.

KEY RESULTS

Apomorphine induced emesis and behaviors suggestive of nausea, and gastric dysrhythmia. The emesis frequency in control session was 5.5 ± 0.99, and symptoms score was 22.17 ± 1.01. GES with short pulse and long pulse could not improve emesis and symptoms induced by apomorphine. The emesis frequency (4.5 ± 0.76 in short pulse and 6.33 ± 1.05 in long pulse) and symptoms scores had no significant difference compared to control session (each p > 0.05). GES with trains of short pulse reduced emesis time frequency (3.83 ± 0.7, p = 0.042 vs control) and symptoms score (p = 0.037 vs control) obviously. Brain fMRI showed that GES with short pulse and long pulse activated brain stem region, and trains of short pulse made amygdala and occipital lobe activation.

CONCLUSIONS & INFERENCES

Apomorphine induced emesis and gastric dysrhythmia. GES with trains of short pulses relieves emetic responses through activation of amygdala region.

Schistosoma japonicum: susceptibility of neonate mice born to infected and noninfected mothers following subsequent challenge

This study was to investigate the differences between neonate mice born to Schistosoma japonicum-infected mothers and those born to noninfected mothers in subsequent challenge. The intensity of infection (evidenced by worm burden and liver egg burden) and liver immunopathology (number and size of liver granulomas) were significantly reduced in neonates from infected mothers (I.M.) compared with neonates from noninfected mothers (N.M.). Anti-soluble worm antigen of S. japonicum (SWA) IgG could be detected in sera of neonates from I.M. (N.N./I.M.) at 1 week after delivery, remained a plateau for 2 weeks and gradually decreased until 8 weeks of age. Parasite-specific IgM was not detected in sera from N.N./I.M. at any time after delivery. At 6 weeks after infection, the level of anti-SWA IgG in infected neonates from I.M. (I.N./I.M.) was significantly higher than that of infected neonates from N.M. (I.N./N.M.). In addition, production of IFN-γ, IL-12 and TGF-β by cultured splenocytes from I.N./I.M. was significantly increased, while the level of IL-4 was significantly decreased when compared to those from I.N./N.M.. These data demonstrate that congenital exposure to schistosomiasis japonica may render neonatal mice born to I.M. less susceptible to subsequent challenge and result in down-regulation of both infection intensity and immunopathology.

Inferred cosmic-ray spectrum from Fermi large area telescope γ-ray observations of Earth's limb

Recent accurate measurements of cosmic-ray (CR) species by ATIC-2, CREAM, and PAMELA reveal an unexpected hardening in the proton and He spectra above a few hundred GeV, a gradual softening of the spectra just below a few hundred GeV, and a harder spectrum of He compared to that of protons. These newly discovered features may offer a clue to the origin of high-energy CRs. We use the Fermi Large Area Telescope observations of the γ-ray emission from Earth's limb for an indirect measurement of the local spectrum of CR protons in the energy range ∼90  GeV-6  TeV (derived from a photon energy range 15 GeV-1 TeV). Our analysis shows that single power law and broken power law spectra fit the data equally well and yield a proton spectrum with index 2.68±0.04 and 2.61±0.08 above ∼200  GeV, respectively.

Alpha, beta and gamma diversity differ in response to precipitation in the Inner Mongolia grassland

Understanding the distribution pattern and maintenance mechanism of species diversity along environmental gradients is essential for developing biodiversity conservation strategies under environmental change. We have surveyed the species diversity at 192 vegetation sites across different steppe zones in Inner Mongolia, China. We analysed the total species diversity (γ diversity) and its composition (α diversity and β diversity) of different steppe types, and their changes along a precipitation gradient. Our results showed that (i) β diversity contributed more than α diversity to the total (γ) diversity in the Inner Mongolia grassland; the contribution of β diversity increased with precipitation, thus the species-rich (meadow steppe) grassland had greater contribution of β diversity than species-poor (desert steppe) grassland. (ii) All α, β and γ species diversity increased significantly (P<0.05) with precipitation, but their sensitivity to precipitation (diversity change per mm precipitation increase) was different between the steppe types. The sensitivity of α diversity of different steppe community types was negatively (P<0.05) correlated with mean annual precipitation, whereas the sensitivity of β and γ diversity showed no trend along the precipitation gradient (P>0.10). (iii) The α diversity increased logarithmically, while β diversity increased exponentially, with γ diversity. Our results suggest that for local species diversity patterns, the site species pool is more important in lower precipitation areas, while local ecological processes are more important in high precipitation areas. In addition, for β diversity maintenance niche processes and diffusion processes are more important in low and high precipitation areas, respectively. Our results imply that a policy of “multiple small reserves” is better than one of a “single large reserve” for conserving species diversity of a steppe ecosystem, and indicate an urgent need to develop management strategies for climate-sensitive desert steppe ecosystem.

Different responses of plant species to deferment of sheep grazing in a desert steppe of Inner Mongolia, China

This paper reports the effects of different deferments of sheep grazing on plant variables of desert steppe vegetation in Inner Mongolia during 2010–2012. The study was initiated in May 2010 and comprised five treatments: no grazing (UG), grazing throughout the growing season (G) and grazing deferment for 40, 50 and 60 days (40UG, 50UG and 60UG) from the start of the growing season in a completely randomised block design replicated three times. The plant species were classified into two functional groups (C3 and C4 species) and the relationships among species composition, biomass and annual precipitation were examined in different deferments of sheep grazing. Treatment G significantly decreased the biomass of several species compared with some of the deferred treatments and treatment UG, because of differences in grazing preferences, and, consequently, decreased the aboveground net primary productivity (ANPP). Grazing deferment for 40, 50 and 60 days significantly increased C3-species richness and biomass compared with treatment UG, whereas grazing sheep’s preferences for C4 plants at some growth stages compared with C3 plants, resulted in lower species richness and biomass of C4 plants in treatments G, 40UG and 50UG in a dry year. Similarly, different species responses to treatment 60UG resulted in an increase in ANPP in a year with more precipitation during the growing season. The annual precipitation patterns strongly affected the temporal changes in biomass as well as the responses to grazing, indicating that the plant responses in the desert steppe were co-limited by grazing and precipitation. These findings provide important insights into the management and conservation of desert steppe vegetation in Inner Mongolia.

Grazing primarily drives the relative abundance change of C4 plants in the typical steppe grasslands across households at a regional scale

Increases in temperature and grazing intensity are believed to promote the relative abundance of C4 plants in grassland communities in Inner Mongolia. However, there is a lack of understanding as to which factor is the primary driver at the household scale. The relative abundance of C4 plants in grassland communities within 32 households was monitored over a 5-year period (2008–12) in the typical steppe region of Inner Mongolia. The relationships between the mean annual temperature, grazing intensity and their combinations on the patterns of the relative abundance of C4 plants across the land managed by these households were analysed. The results showed that (1) the herbage mass of the typical steppe grassland was mainly composed of C3 plants (87%); (2) the C4 plants were more sensitive to, and can be used as indicators of, environmental changes. These C4 species included Cleistogenes squarrosa (Trin.) Keng, Chenopodium glaucum Linn. and Salsola collina Pall.; (3) both increasing temperature and grazing intensity promoted the relative abundance of C4 plants. Grazing intensity was the primary driver of the change in relative abundance of C4 plants in this region. Not only did grazing change the micro-environment of the grasslands, but also the C3 species were preferentially grazed by the livestock. Comparison of the results with previous studies on the temporal variation in the abundance of C4 plants suggests that the relative importance of grazing and climatic factors depends on the spatial scales of the studies, with climate being of greater importance at the regional rather than the household scale.

Response of the annual biomass production of a typical steppe plant community to precipitation fluctuations

Understanding the relationship between the aboveground net primary production (ANPP) and annual precipitation in arid and semiarid grasslands is crucial for assessing the effects of climate change on grassland ecosystems. The temporal pattern of ANPP, based on long-term data on a semiarid ecosystem in Inner Mongolia, was investigated. The biomass of perennial grasses, perennial forbs and Stipa grandis P. Smirn., showed a positive relationship with annual precipitation. The amount of annual precipitation also changed the annual biomass of 13 other dominant species and consequently the ANPP. The coefficient of variation of the ANPP of the plant community was lower than the coefficient of variation of annual precipitation. Irrespective of the strong inter-annual variation in annual precipitation, the positive relationship found between ANPP and annual precipitation suggests the dependence of ANPP upon hydrological variations in typical steppe. Our findings highlight the importance of dominant perennial species and functional groups in mediating the responses of ANPP to annual precipitation in the typical steppe in northern China.

Herders’ opinions about desirable stocking rates and overstocking in the rangelands of northern China

Herders’ desirable stocking rates and their opinions of overstocking were studied using survey and multi-regression methods in the meadow steppe, typical steppe and desert steppe regions of northern China. It was found that individual herders had their own perception of their particular ‘desirable stocking rate’, which referred to the number of livestock that the herders thought they could keep or maintain on an area of rangeland over a specified period of time. These perceptions were not in line with the ‘balancing animals and grass’ policy of the Chinese government, and herders used them as a guide to adjust stock-breeding practices. Most herders admitted that they bred more livestock now than 10 years ago, but insisted that there was no overstocking and many even thought that their rangelands could still carry more livestock. They also held the view that they took into account the carrying capacity of rangelands when making decisions about livestock-breeding practices. Individual herders thought that the reasonable stocking rate range should be 0.75–1.50 sheep units ha–1 (meadow steppe), 0.60–1.50 sheep units ha–1 (typical steppe), and 0.50–0.75 sheep units ha–1 (desert steppe), respectively. The herders from the desert steppe regions were most concerned about the overstocking of rangelands, and the concern of herders was in the order desert steppe > typical steppe > meadow steppe. The herders with more formal education and those who worked in a village council and had smaller areas of rangelands, were more concerned about the overstocking of rangelands. It is argued that such herders should be given more access to policy and market information, including extensive grazing and modern stall-feeding technologies, and encouraged to reduce their desirable stocking rates, leading to more sustainable rangeland management in northern China.

Herders’ perception of climate change does not always fit with actual climate change

Herders’ perceptions are important in relation to adopting adaptive behavioural approaches to climate change. A survey of 1080 herder households was conducted in six rangeland regions of Inner Mongolia in northern China to investigate relationships between herder’s perceptions and actual climate change. Across all six regions, more than 90% of herders perceived a decline in precipitation in the past 30 years, whereas actual data showed no significant change. Many herders also perceived an increase in temperature, which was in agreement with the temperature data, although the proportion of herders who perceived a change in temperature differed among regions. A further survey of 58 households was conducted to better understand the reasons for these differences, by simultaneously surveying their perceptions of the changes in both rainfall and rangeland condition. The results showed that the herders’ perceptions of a decrease in rainfall could be influenced by their perceptions of the changes in the condition of their rangeland (reductions in production). An alternative explanation could relate to rainfall being interpreted in terms of the frequency and pattern rather than the absolute amounts. These findings have important implications for understanding how herders’ perceptions can improve their adaptive behavioural responses to climate change.

Climate changes during the past 31 years and their contribution to the changes in the productivity of rangeland vegetation in the Inner Mongolian typical steppe

The objectives of this study were to explore the impact of climate change and human activities on the annual production of aboveground biomass of vegetation during the past 31 years at a county scale in the typical steppe region of Inner Mongolia. The changes in three banners in the region (Abag Banner, Xilinhaote City, and Xiwuzhumuqin Banner) were analysed. The changes in the annual potential grassland production (net primary productivity) and in the annual production of vegetation, as the sum of aboveground biomass and consumption by livestock, were estimated for each year. A comparison of the changing rates in net primary productivity and aboveground biomass of vegetation over the 31 years was used to distinguish the effects of climate change on grassland production from human activities. The results showed that the climate had become warmer and drier during the past 31 years and thus net primary productivity and annual production of vegetation decreased significantly. Climate change was a major factor for these decreases, while human activities were a minor factor in the decrease of grassland production in Xuwuzhumuqi Banner. The importance of human activities in reducing this decrease in grassland production during the last 31 years is in accordance with the changes in grassland-use policy that has encouraged destocking for grassland restoration in recent years.

Assessment of vulnerability to climate change in the Inner Mongolia steppe at a county scale from 1980 to 2009

Most of Inner Mongolia is covered with natural grassland and is highly sensitive to global climate change because of the physical geography, the highly variable climate, and the complicated socioeconomic conditions. The climate is generally wetter in the east becoming drier towards the west of the region. Using a Pressure-State-Response model to select climate-related assessment indicators, a vulnerability assessment to climate change framework of counties in Inner Mongolia was built, which included three layers and 17 indicators. Climate change vulnerability of eight counties in the steppe area of Inner Mongolia was assessed from 1980 to 2009. The results showed that in the past 30 years, climate change vulnerability of eight counties has decreased with the decrease more pronounced after 2000. The lowest value for vulnerability was in 2008. The vulnerability of the western region was higher than that of the eastern region. Counties with a desert ecological system had a higher vulnerability than counties with steppe. Under the background of exposure increasing and sensitivity slightly decreasing, a continuing significant improvement in adaptive capacity is the key reason for a reduction invulnerability of the Inner Mongolia steppe area to climate change. The volatility of the climate on an inter-annual scale can cause changes in vulnerability between years. With the development of the rural economy and increases in national investment in the environment, the vulnerability of the Inner Mongolian steppe has been significantly reduced, but, overall, the vulnerability remains high. Most of the counties are moderately vulnerable, some counties are seriously vulnerable, even extremely vulnerable, and strong measures need to be adopted to strengthen the ability to adapt to climate change.

Identification of differentially accumulating pistil proteins associated with self-incompatibility of non-heading Chinese cabbage

Non-heading Chinese cabbage (Brassica campestris L. ssp. chinensis Makino), an important vegetable crop in China, exhibits a typical sporophytic self-incompatibility (SI) system. To better understand the mechanism of SI response and identify potential candidate proteins involved in the SI system of this vegetable crop, the proteomic approach was taken to identify differential accumulating pistil proteins. Pistils were collected at 0 h and 2 h after self-pollination at anthesis in self-incompatible and compatible lines of non-heading Chinese cabbage, and total proteins were extracted and separated by two-dimensional gel electrophoresis (2-DE). A total of 25 protein spots that displayed differential abundance were identified by matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF/TOF MS) and peptide mass fingerprinting (PMF). Among them, 22 protein spots were confidently established. The mRNA levels of the corresponding genes were detected by quantitative RT-PCR. The 22 identified protein spots are involved in energy metabolism (four), protein biosynthesis (three), photosynthesis (six), stress response and defence (five), and protein degradation (four). Among these potential candidate proteins, UDP-sugar pyrophosphorylase could be involved in sucrose degradation to influence pollen germination and growth. Glutathione S-transferases could be involved in pollen maturation, and affect pollen fertility. Senescence-associated cysteine protease, which is related to programmed cell death, could be mainly related to self pollen recognition of non-heading Chinese cabbage. The study will contribute to further investigations of molecular mechanism of sporophytic SI in Brassicaceae.

The response of grassland productivity, soil carbon content and soil respiration rates to different grazing regimes in a desert steppe in northern China

Soil respiration is a major process for organic carbon losses from arid ecosystems. A field experiment was conducted in 2010 and 2012 on the responses to continuous grazing, rotational grazing and no grazing on desert steppe vegetation in northern China. The growing season in 2010 was relatively dry and in 2012 was relatively wet. The results showed that mean soil respiration was the highest with no grazing in both growing seasons. Compared with no grazing, the soil respiration was decreased by 23.0% under continuous grazing and 14.1% under seasonal rotational grazing. Soil respiration increased linearly with increasing soil water gravimetric content, aboveground net primary productivity (ANPP), belowground net primary productivity (BNPP) and soil carbon and nitrogen contents across the 2 years, whereas a negative correlation was detected between soil respiration and soil temperature. A significant decrease in soil respiration was observed under both continuous grazing and in seasonal rotational grazing in the dry growing season, but no significant difference was detected in the wet growing season. In the wet year, only a non-significant difference in soil respiration was observed between different grazing types. Patterns of seasonal precipitation strongly affected the temporal changes of soil respiration as well as its response to different grazing types. The findings highlight the importance of differences in abiotic (soil temperature, soil water gravimetric content and soil carbon and nitrogen contents) and biotic (ANPP, BNPP and litter mass) factors in mediating the responses of soil respiration to the different grazing regimes.

Evaluation of the livelihood vulnerability of pastoral households in Northern China to natural disasters and climate change

This study was carried out to evaluate the vulnerability of the herders in the grassland areas of Northern China. The results showed that, as a consequence of less capital accumulation, the herders in this area were vulnerable as a whole, and that gender, grassland area, livestock numbers and net incomes have significant effects on the vulnerability of grazer households. The families with female householders tended to be more vulnerable and they were characterised as owning less grassland, smaller houses, fewer or no vehicles, fewer young livestock and numbers of livestock slaughtered annually, whereas the families with low vulnerability had a higher net income. Geographically, household vulnerability showed a decreasing trend from west to east in Northern China at the county or region scale, which was positively correlated with grassland productivity. Social resources played a less important role than natural resources in decreasing the herders’ vulnerability. Educational level of the household members and the household labour capacity played important roles in reducing vulnerability. Increasing the enrolment rate and the education background in grassland regions may decrease the vulnerability of the herders. It is argued that the use of vulnerability indices can be helpful to increase the herders’ adaptation to climate change and to improve the sustainability of rural pastoral regions.

Simple and rapid data-reduction method with pixel-level spatial frequency of shift-rotation method

Absolute testing methods are commonly employed in surface metrology to calibrate the reference surface deviation and obtain the absolute deviation of the surface under test. A simple and reliable data-reduction method of absolute shift-rotation method with rotational and translational measurements is presented here, which relies on the decomposition of the surface deviation into rotationally asymmetric and symmetric components. The rotationally asymmetric surface deviation can be simply obtained by classical N-position averaging method. After that, the two-dimensional problem of estimating the other rotationally symmetric surface deviation can be simplified to a one-dimensional problem, and it can be directly calculated out with pixel-level spatial frequency based on several measurements of different translations in one same direction. Since that no orthogonal polynomials fitting, such as Zernike polynomials, is required in the calculation, the data reduction of the method is simple and rapid. Experimental absolute results of spherical surfaces are given.