学科融合背景下生物学与化学跨学科教学的问题与建议

本文从学生、教师以及教材出发,围绕高中生物学和化学的跨学科教学展开讨论,从科学性、一致性和先后性等方面探讨了学科融合在实际教学中可能面临的问题及实施措施。

生物学与化学跨学科核心素养及概念初探

跨学科概念能够打破学科界限,提供高阶思维工具,利于培养全面发展的人。本文分析了生物学与化学学科核心素养的贯通之处,总结出“结构与性质相适应、性质与功能相适应”这一生物学—化学跨学科核心素养,提炼出“生命活动的本质包括化学键的重组和化学分子间的作用力变化”这一生物学—化学跨学科大概念,为深入的跨学科研究提供初步建议。

Cosmic Ray-driven Bioenergetics for Life in Molecular Clouds

According to models such as panspermia or the Nebula-Relay hypothesis,the ancestors of life on Earth once lived in molecular clouds.Then what are the energy source and bioenergetics for such lifeforms?A new bioenergetic mechanism powered by cosmic ray ionization of hydrogen molecules is proposed and its relation with the origin of chemiosmosis is also discussed in this paper.Based on this mechanism,the Last Universal Common Ancestor may be a type of lifeform that utilizes hydrogen molecules as donors of electron transport chains.

Effect of moderately thermophilic bacteria on metal extraction and electrochemical characteristics for zinc smelting slag in bioleaching system

The effects of moderately thermophilic bacteria on the extraction of metals from zinc smelting slag and electrochemical characteristics of zinc smelting slag carbon paste electrode in bioleaching process were studied. The results show that the extraction rates of Fe, Cu and Zn from the slag reach 86.7%, 90.3% and 66.7% after adsorbed bacteria sterilize, while those with adsorbed bacteria are 91.9%, 96.0% and 84.5% in conditions of pulp density 2%, pH 1.0, temperature 65 °C and stirring rate 120 r/min, respectively. Some stretching peaks of functional groups from bacterial secretes on the bioleached residue surface, such as 1007 cm-1 and 1193 cm-1, turn up through FI-IR analysis and indirectly reveal the presence of the adsorbed bacteria on the slag particles surface. Besides, the corrosion of zinc smelting slag is enhanced by bacteria according to the characteristics of cyclic voltametry and Tafel curves in bioleaching system.

Application of N: P Stoichiometry to Ecology Studies

Stoichiometry has long been addressed in the studies of ecosystem ecology, but it was almost ignored for a long time. Until recently, ecologists have become aware that stoichiometry could provide a new tool to study ecology from genes to the biosphere. Among this trend, N:P stoichiometry is used actively in ecological interactions since nitrogen (N) and phosphorus (P) are the two most important elements in most ecosystems. This article reviews the application of N:P stoichiometry to the studies of ecological problems at different levels, including ecosystem, community and species. Meanwhile, we also provide the cellular basis of N:P stoichiometry, identify the shortages in the use of N:P stoichiometry theory, and put forward some perspectives for future research to be conducted.

Research on Stoichiometry of Early-spring Herbs Functional Group in the Subtropical Artificial Wetland

[Objective]The aim was to carry out stoichiometry on the early-spring herbs functional group in subtropical artificial wetland.[Method]UV-Vis spectrophotometer was used for the determination of nitrate-nitrogen,ammonium nitrogen and phosphorus concentrations.Potassium persulfate absorptiometry was used for the measurement of total N content,while the flame photometer was used to detect the potassium and sodium concentration in plants.All the nutrient determination of plant samples were repeated for four times.[Result]The four nutrient concentrations in almost all samples were in the normal range of natural plant nutrition concentrations;in early-spring herbs functional groups,different species showed diversity on the nutrient concentrations;plant height had no significant effect on the nutrient concentrations in plants;the nutrient concentrations of non-grass group plants were higher than that of grass group plants;the nutrient concentrations of the annual herb were higher than that of perennial herbs.[Conclusion]The study had provided basis for the understanding of the effects of changes in nutritional conditions on species diversity,community structure and succession of the system.

Tupu methods of spatial-temporal pattern on land use change:a case study in the Yellow River Delta

Comprehensive study on land-use change of spatial pattern and temporal process is the key component in LUCC study nowadays. Based on the theories and methods of Geo-information Tupu (Carto-methodology in Geo-information, CMGI), integration of spatial pattern and temporal processes of land-use change in the Yellow River Delta (YRD) are studied in the paper, which is supported by ERDAS and ARC/INFO software. The main contents include: (1) concept models of Tupu by spatial-temporal integration on land-use change, whose Tupu unit is synthesized by "Spatial·Attribute·Process" features and composed of relatively homogeneous geographical unit and temporal unit; (2) data sources and handling process, where four stages of spatial features in 1956, 1984, 1991, and 1996 are acquired; (3) integration of series of temporal-spatial Tupu, reconstruction series of "Arising" Tupu, spatial-temporal Process Tupu and the spatial temporal Pattern Tupu on land-use change by remap tables; (4) Pattern Tupu analysis on land-use change in YRD during 1956-1996; and (5) spatial difference of the Pattern Tupu analysis by dynamic Tupu units. The various landform units and seven sub-deltas generated by the Yellow River since 1855 are different. The Tupu analysis on land-use in the paper is a promising try on the comprehensive research of "spatial pattern of dynamic process" and "temporal process of spatial pattern" in LUCC research. The Tupu methodology would be a powerful and efficient tool on integrated studies of spatial pattern and temporal process in Geo-science.

BIOLOGICAL AND CHEMICAL STUDIES OF SEA- SURFACE MICROLAYER (SML) IN DAYA BAY, CHINA IIA.BIOLOGICAL AND CHEMICAL CHARACTERISTICS OF THE SML AND THE CORRELATION AMONG THEM

Two cruises for multi discipline investigation were conducted in October and November, 1998 in Daya Bay to collect: (1) samples from five levels including sea surface microlayer (SML), subsurface (SSL), surface, body (mid column) and bottom water; and (2) observational data on chlorophyll a and nutrients, and important factors such as turbidity, BOD, COD, TN, TP and phytoplankton. Results showed that there was no enrichment of chlorophyll a in the SML, but quite notable enrichment of some organic matter and nutrients. Compared with the findings in earlier researches, PO 4 P and SiO 3 Si have decreased, and the N/P ratio has increased obviously to even more than 100 in the SML. It is concluded preliminarily that PO 4 P and SiO 3 Si mainly determine phytoplankton growth in Daya Bay at present.

Siderophores from Marine Microorganisms and Their Applications

In view of the fact that siderophores from microorganisms in different environments have received much attention in recent years because of their potential applications and diverse physiological functions, this review deals with side rophore producing marine microorganisms and the detection, chemical structure and potential applications of siderophores.

Alteration of certain soil microbiological and biochemical indices of a paddy soil under anthropogenic stress

A 21-day laboratory incubation experiment was conducted to investigate the impact of pesticides (insecticide, herbicide, fungicide) on paddy field soil health under controlled moisture (flooded soil) and temperature (25 ℃) environment. The electron transport system (ETS)/Dehydrogenase activity showed negative correlation with pesticides concentrations, decreased with increase of pesticide concentration. The higher doses(5 to 10 times field rates) of pesticides significantly inhibited ETS activity, while lower rates failed to produce any significant reducing effect on the control. The toxicity of pesticides in decreasing the ETS activity was in the order: insecticide > fungicide > herbicide, irrespective of their rates of application. The pesticides increased the soil phenol content, which increased with increasing concentration of agrochemicals. The pesticide application did not produce any significant change in soil protein content. The response of biomass phospholipid content was nearly similar to that of ETS activity. The phospholipid content decreased with the addition of pesticides in the order insecticide > fungicide > herbicide and the toxicity was in the order: 10 FR (field rate) > 5 FR > 1.0 FR > 0.5 FR > control.

New insights into the activation mechanism of store-operated calcium channels:roles of STIM and Orai

The activation of Ca2+ entry through store-operated channels by agonists that deplete Ca2+ from the endoplasmic reticulum (ER) is a ubiquitous signaling mechanism, the molecular basis of which has remained elusive for the past two decades. Store-operated Ca2+-release-activated Ca2+ (CRAC) channels constitute the sole pathway for Ca2+ entry following antigen-receptor engagement. In a set of breakthrough studies over the past two years, stromal interaction molecule 1 (STIM1, the ER Ca2+ sensor) and Orai1 (a pore-forming subunit of the CRAC channel) have been identified. Here we review these recent studies and the insights they provide into the mechanism of store-operated Ca2+ channels (SOCCs).

Ecological control of forest pest： a new strategy for forest pest control

In comparison with integrated pest management and chemical control, the authors put forward a new strategy of forest pest control, named ecological control of forest pest （ECFP）. This paper reviewed the development history, summarized the concept and principles of ECFP, discussed the technology and methods of ECFP, and evaluated the ECFP and its application conditions.

Effect of Lanthanum on Major Microbial Populations in Red Soil

Pure culture and pot culture experiments were carried out to study the effect of lanthanum (La) on bacteria, actinomyces and fungus, and some microbial physiological groups , nitrifier, azotobacter and phos- phobacteria, in a red soil taken form the Ecological Experimental Station of Red Soil, the Chinese Academy of Sciences, Jiangxi Province. LaCl3 was added into media at levels of 0, 25, 50, 100, 150, 200, 250 and 500 mg L-1 in the pure culture experiment, and into soil samples in porcelain pots before rice growing at levels of 0, 6, 30, 150, 300, 600 and 900 mg kg-1 dry soil in the pot culture experiment. The populations of the three soil microbes in the pure culture experiment decreased with the addition level of La, indicating that La was toxic to the soil microbes in pure culture, and the sensitivity of the 3 major microbial types to La was in a decreasing order of actinomyces > bacteria > fungus. In the pot experiment, La had slightly stimulative effect on soil bacteria and actinomyces when applied at low concentrations while had inhibitory effect on soil bacteria, actinomyces and fungus at high concentrations. When the concentration of La was low, soil azotobacter was stimulated slightly while soil nitrifier was stimulated strongly and the maximum increase was up to 50%. When the concentration of La was high, both soil azotobacter and nitrifier were inhibited, and the inhibition of La to the nitrifier increased with La concentration. La added at all the levels had stimulative effect on soil inorganic and organic phosphobatteria. Among the 4 physiological groups, soil nitrifier was most sensitive to La, so , it might be reasonable to assume that soil nitrifier was a sensitive indicator for evaluating the biological and environmental effects of rare earths.

Characterization of Mediterranean Magnetotactic Bacteria

Magnetotactic bacteria are a diverse group of motile prokaryotes that are ubiquitous in aquatic habitats and cosmopolitan in distribution. In this study, we collected magnetotactic bacteria from the Mediterranean Sea. A remarkable diversity of morphotypes was observed, including multicellular types that seemed to differ from those previously found in North and South America. Another interesting organism was one with magnetosomes arranged in a six-stranded bundle which occupied one third of the cell width. The magnetosome bundle was evident even under optic microscopy. These cells were connected together and swam as a linear entire unit. Magnetosomes did not always align up to form a straight linear chain. A chain composed of rectangle magnetosomes bent at a posi- tion with an oval crystal. High resolution transmission electron microscopy analysis of the crystal at the pivotal position suggested uncompleted formation of the crystal. This is the first report of Mediterranean magnetotactic bacteria, which should be useful for studies of biogeochemical cycling and geohistory of the Mediterranean Sea.

Evidence for the involvement of infectious agents in the pathogenesis of Crohn's disease

Many advances have been made in the understanding of Crohn’s disease (CD) pathogenesis during the last decade. CD is currently seen as a predominantly T-lym-phocyte-driven disease characterized by the presence of a complex cocktail of interacting cytokines, chemokines and other mediators produced by a variety of cell types. Prevailing theories of CD pathogenesis suggest that patients’ T-lymphocytes are inappropriately activated in the setting of an immune imbalance, which is itself caused by an unfortunate confluence of genetic and en- vironmental factors. The T-cell response then leads to the chronic inflammation characteristic for the disease. Various environmental factors may play a role in the development of CD, but microbes are most consistently implied. This theory is based on epidemiological, clinico- pathological, genetic and experimental evidence. Despite the abundance of arguments for the implication of bac-teria in the aetiopathogenesis of CD, the precise role of bacteria in this disease still remains elusive. Three not necessarily mutually exclusive theories have been pro- posed: (1) an unidentified persistent pathogen; (2) an abnormally permeable mucosal barrier leading to exces-sive bacterial translocation; and (3) a breakdown in the balance between putative "protective" versus "harmful" intestinal bacteria ("dysbiosis"). At present, one cannot exclude with certainty any of these three proposed hy-potheses; they may all apply to CD to a certain extent.

SPARCL1, Shp2, MSH2, E-cadherin, p53, ADCY-2 and MAPK are prognosis-related in colorectal cancer

AIM: To investigate the expression of markers that are correlated with the prognosis of colorectal cancer (CRC) patients. METHODS: One hundred and fifty-six CRC patientswere followed up for more than 3 years after radical surgery. Immunohistochemical (IHC) analysis was performed to detect the expression of 14 pathway-related markers (p53, APC, p21ras, E-cadherin, endothelin-B receptor, Shp2, ADCY-2, SPARCL1, neuroligin1, hsp27, mmp-9, MAPK, MSH2 and rho) in specimens from these patients. Bioinformatics analysis involving a Support Vector Machine (SVM) was used to determine the best prognostic model from combinations of these markers. RESULTS: Seven markers (SPARCL1, Shp2, MSH2, E-cadherin, p53, ADCY-2 and MAPK) were significantly related to the prognosis and clinical pathological features of the CRC patients (P < 0.05). Prognostic models were established through SVM from combinations of these 7 markers and proved able to differentiate patients with dissimilar survival, especially in stage Ⅱ/Ⅲ patients. According to the best prognostic model, the p53/SPARCL1 model, patients having high p53 and low SPARCL1 expression had about 50% lower 3-year survival than others (P < 0.001). CONCLUSION: SPARCL1, Shp2, MSH2, E-cadherin, p53, ADCY-2 and MAPK are potential prognostic markers in CRC. A p53/SPARCL1 bioinformatics model may be used as a supplement to tumor-nodes-metastasis staging.

Virological course of hepatitis A virus as determined by real time RT-PCR: Correlation with biochemical, immunological and genotypic profiles

AIM： To undertake analysis of hepatitis A viral load, alanine aminotransferase （ALT）, and viral genotypes with duration of viremia, and to correlate these parameters with CD4^＋/ CD8^＋ lymphocyte populations that control cell-mediated immunity. METHODS： Cell counts were carried out using fresh whole blood collected in EDTA vials using a fluorescence activated cell sorter. Hepatitis A virus （HAV） RNA was extracted from blood serum, reverse transcribed into cDNA and quantified by Real-Time polymerase chain reaction and was genotyped. RESULTS： Among 11 patients, 10 could be analyzed completely. Of these, 3 had severe acute hepatitis （s-AH） and the remainder had a self-limited acute hepatitis A （AHA）, with one patient with fulminant disease （encephalopathy Grade IV） dying on the 4^th d. The ALT level was significantly higher both in AHA （1070.9±894.3; P = 0.0014） and s-AH （1713.9±886.3; P = 0.001） compared to normal controls （23.6±7.2）. The prothrombin time in s-AH patients （21.0 ±2.0; P=0.02） was significantly higher than in AHA （14.3±1.1;P = 0.44）. The CD4^＋/CD8^＋ ratio in AHA patients （1.17 ＋ 0.11; P = 0.22） and s-AH （0.83 ＋ 0.12; P = 0.0002） were lower than seen in normal healthy controls （1.52）. Self-limited cases had peak viral load at the beginning of analysis while in s-AH patients this occurred at the 15TM or 30^th d. In acute and severe groups, one patient each belonged to genotype IA, with the remaining 8 cases belonging to genotype IIIA. The only fulminant hepatic failure case belonged to genotype IA. HAV viral load and AIT values collected during the entire course of the selflimited infection were directly correlated but this was not the case for s-AH patients.CONCLUSION： Based on a small-scale study, the persistently higher viral load of s-AH might be due to diminished cellular immunity and hemolysis. The duration of viremia was dependent on the host, as the viral genotype had no apparent role in clinical outcome of AVH and s-AH cases.

Water Chemistry and Hydrometeorology in a Glacierized Catchment in the Polar Urals,Russia

This study aims to determine the relationships between local meteorological conditions,proglacial river discharge and biogeochemical processes operating in a periglacial basin located in the Polar Ural mountain range, Russia. Fieldwork was conducted in the catchment of Obruchev Glacier(13 km2) during the summer peak flow period in 2008. River discharge was dominated by snowmelt and changed from 3300 l s-1 to less than 1000 l s-1. The mean daily air temperatures of stations situated in the mountain tundra and near Obruchev Glacier from July 11 th to August 1st 2008 were 14.4°C and 10.3°C, respectively. The glacial river had low total dissolved solids varying from 4.5 to 9 mg l-1 and coefficients of correlation between Na+ and Cl-, K+ and Cl-, as well as NH4+ and Cl- were 0.94, 0.90 and 0.84, respectively. Rainfall events affected the snowmelt initiation and provided an essential part of the discharge during the intense snowmelt period, which occurred from July 11 th to July 18 th 2008. Data showed that Na+ and K+ in the surface water derived from snowmelt rather than chemical weathering of silicates. Also, it was obtained that NO3- derived from the melting snowpack, whereas ammonification occurring under the snowpacks was the primary source for NH4+.

Glutamine depletion induces murine neonatal melena with increased apoptosis of the intestinal epithelium

AIM:To investigate the possible biological outcome and effect of glutamine depletion in neonatal mice and rodent intestinal epithelial cells.METHODS:We developed three kinds of artificial milk with different amounts of glutamine;Complete amino acid milk (CAM),which is based on maternal mouse milk,glutamine-depleted milk (GDM),and glutaminerich milk (GRM).GRM contains three-fold more glutamine than CAM.Eighty-seven newborn mice were divided into three groups and were fed with either of CAM,GDM,or GRM via a recently improved nipple-bottle system for seven days.After the feeding period,the mice were subjected to macroscopic and microscopic observations by immunohistochemistry for 5-bromo-2'deoxyuridine (BrdU) and Ki-67 as markers of cell proliferation,and for cleaved-caspase-3 as a marker of apoptosis.Moreover,IEC6 rat intestinal epithelial cells were cultured in different concentrations of glutamine and were subject to a 4-[3-(4-iodophenyl)-2-(4-nitrophenyl)2H-5-tetrazolio]-1,3-benzene disulfonate cell proliferation assay,flow cytometry,and western blotting to examine the biological effect of glutamine on cell growth and apoptosis.RESULTS:During the feeding period,we found colonic hemorrhage in six of 28 GDM-fed mice (21.4%),but not in the GRM-fed mice,with no differences in body weight gain between each group.Microscopic examination showed destruction of microvilli and the disappearance of glycocalyx of the intestinal wall in the colon epithelial tissues taken from GDM-fed mice.Intake of GDM reduced BrdU incorporation (the average percentage of BrdU-positive staining;GRM:13.8%,CAM:10.7%,GDM:1.14%,GRM vs GDM:P < 0.001,CAM vs GDM:P < 0.001) and Ki-67 labeling index (the average percentage of Ki67-positive staining;GRM:24.5%,CAM:22.4% GDM:19.4%,GRM vs GDM:P=0.001,CAM vs GDM:P =0.049),suggesting that glutamine depletion inhibited cell proliferation of intestinal epithelial cells.Glutamine deprivation further caused the deformation of the nuclear membrane and the plasma membrane,accompanied by chromatin degeneration and an absence of fat droplets from the colonic epithelia,indicating that the cells underwent apoptosis.Moreover,immunohistochemical analysis revealed the appearance of cleaved caspase-3 in colonic epithelial cells of GDM-fed mice.Finally,when IEC6 rat intestinal epithelial cells were cultured without glutamine,cell proliferation was significantly suppressed after 24 h (relative cell growth;4 mmol/L:100.0% ± 36.1%,0 mmol/L:25.3% ± 25.0%,P < 0.05),with severe cellular damage.The cells underwent apoptosis,accompanied by increased cell population in sub-G0 phase (4 mmol/L:1.68%,0.4 mmol/L:1.35%,0 mmol/L:5.21%),where dying cells are supposed to accumulate.CONCLUSION:Glutamine is an important alimentary component for the maintenance of intestinal mucosa.Glutamine deprivation can cause instability of the intestinal epithelial alignment by increased apoptosis.

A Novel Triterpenic Acid from Gymnema sylvestre

A novel oleanane-type triterpenic acid was isolated from the leaves of Gymnema sylvestre(Asclepiadaceae). The structure was characterized as 3β, 16β, 22β, 28-tetrahydroxy- olean-12-en-30-oic acid on the basis of spectral evidence, including 1D- and 2D-NMR (HMQC, HMBC, H-1H 1COSY and NOESY).