基于钙黄绿素- 铜(Ⅱ)荧光体系测定乙酰半胱氨酸

目的:基于钙黄绿素-铜(Ⅱ)荧光体系测定乙酰半胱氨酸。方法:在pH=8.0的Na2HPO.412H2O-KH2PO4缓冲液中,以492 nm为激发波长,520 nm为发射波长测定乙酰半胱氨酸溶液的荧光强度。结果:在pH=8.0的Na2HPO.412H2O-KH2PO4缓冲液中,二价铜离子与钙黄绿素配位引起荧光猝灭。由于乙酰半胱氨酸中巯基上的硫离子与Cu2+的亲和力很强,可从钙黄绿素-铜(Ⅱ)的络合物中夺取铜离子而使钙黄绿素游离出来,从而使体系的荧光得以恢复,并且荧光恢复的程度与加入乙酰半胱氨酸的量在一定范围内成线性。结论:建立了一种测定乙酰半胱氨酸的荧光分析新方法,该方法的线性范围为6.0 10-6～1.4 10-5 mol/L,检出限为4.010-6 mol/L。     

Identification of stable fly attractant compounds in vinasse,a byproduct of sugarcane–ethanol distillation

The stable fly, Stomoxys calcitrans (Diptera: Muscidae), is a worldwide pest of livestock. Recent outbreaks of stable flies in sugarcane fields in Brazil have become a serious problem for livestock producers. Larvae and pupae found inside sugarcane stems after harvesting may indicate that stable flies use these stems as potential oviposition or larval development sites. Field observations suggest that outbreaks of stable flies are associated with the vinasse and filter cake derived from biomass distillation in sugarcane ethanol production that are used as fertilizers in sugarcane fields. Adult stable flies are attracted to vinasse, which appears to present an ideal larval development site. The primary goal of the present study is to demonstrate the role of vinasse in influencing the sensory physiological and behavioural responses of stable flies, and to identify its associated volatile attractant compounds. Both laboratory and field studies showed that vinasse is extremely attractive to adult stable flies. Chemical analyses of volatiles collected revealed a wide range of carboxylic acids, alcohols, phenols and aldehydes as potential attractant compounds. These newly identified attractants could be used to develop a tool for the attractant‐baited mass trapping of stable flies in order to reduce infestations.     

功能矫形前伸青春期大鼠下颌后浅层嚼肌细胞凋亡的研究

目的：研究功能矫形前伸大鼠下颌后浅层嚼肌细胞凋亡的变化规律,探讨功能矫形的肌肉改建机理。方法：选用50只5周龄Sprague-Dawley（SD）雄性大白鼠,随机分为实验组和对照组各25只。实验组大鼠戴自制上颌功能矫治嚣,引导下颌前伸,并打开咬合。利用RT-PCR方法检测两组大鼠浅层嚼肌Bcl-2和Bax基因表达情况,利用TUNEL方法检测浅层嚼肌细胞凋亡情况。结果：①Bcl-2和Bax基因表达随大鼠戴用矫治器时间的延长而升高,至第3周开始下降但仍高于对照组,但Bax的表达高于Bcl-2。Bax/Bcl-2比值随大鼠戴用矫治器时间的延长而升高,至第4周开始下降。②TUNEL实验结果显示浅层嚼肌细胞在戴用矫治器1天后,开始出现凋亡,随着时间延长而增加,至第3周达到顶峰,第4周开始下降。结论：①Bax/Bcl-2比值升高促进浅层嚼肌细胞凋亡。②功能矫形可引起浅层嚼肌细胞凋亡,导致肌肉的结构和功能发生适应性改建。     

Beringian paleoecology inferred from permafrost-preserved fungal DNA

The diversity of fungi in permanently frozen soil from northeastern Siberia was studied by culture-independent PCR amplification of diverse environmental 18S rRNA genes. Elaborate protocols to avoid contamination during drilling, sampling, and amplification were used. A broad diversity of eukaryotic DNA sequences that were 510 bp long, including sequences of various fungi, plants, and invertebrates, could be obtained reproducibly from samples that were up to 300,000 to 400,000 years old. The sequences revealed that ancient fungal communities included a diversity of cold-adapted yeasts, dark-pigmented fungi, plant-parasitic fungi, and lichen mycobionts. DNA traces of tree-associated macrofungi in a modern tundra sample indicated that there was a shift in fungal diversity following the last ice age and supported recent results showing that there was a severe change in the plant composition in northeastern Siberia during this period. Interestingly, DNA sequences with high homology to sequences of coprophilic and keratinophilic fungi indicated that feces, hair, skin, and nails could have been sources of ancient megafauna DNA recently reported to be present in small amounts of Siberian permafrost sediments.     

Isolation and characterization of microsatellite markers from Pacific white shrimp (Litopenaeus vannamei)

We report the development of 11 polymorphic microsatellite loci in pacific white shrimp (Litopenaeus vannamei) using an unenriched genomic library. The number of the alleles ranged from two to 18 and observed hererozygosity ranged from 0.0286 to 0.9429, indicating that these markers will be useful for population studies and mapping in pacific white shrimp. Seven loci were detected deviated from Hardy–Weinberg, caused by deficiency of heterozygote, suggesting population genetic structure across the sampled population. No evidence for linkage disequilibrium was found.     

A biophysical model of Sugarcane growth

Scientists predict that global agricultural lands will expand over the next few decades due to increasing demands for food production and an exponential increase in crop‐based biofuel production. These changes in land use will greatly impact biogeochemical and biogeophysical cycles across the globe. It is therefore important to develop models that can accurately simulate the interactions between the atmosphere and important crops. In this study, we develop and validate a new process‐based sugarcane model (included as a module within the Agro‐IBIS dynamic agro‐ecosystem model) which can be applied at multiple spatial scales. At site level, the model systematically under/overestimated the daily sensible/latent heat flux (by ?10.5% and 14.8%, H and λE, respectively) when compared against the micrometeorological observations from southeast Brazil. The model underestimated ET (relative bias between ?10.1% and –12.5%) when compared against an agro‐meteorological field experiment from northeast Australia. At the regional level, the model accurately simulated average yield for the four largest mesoregions (clusters of municipalities) in the state of São Paulo, Brazil, over a period of 16 years, with a yield relative bias of ?0.68% to 1.08%. Finally, the simulated annual average sugarcane yield over 31 years for the state of Louisiana (US) had a low relative bias (?2.67%), but exhibited a lower interannual variability than the observed yields.     

A new species of Eugenia (Myrtaceae) from south‐eastern Brazil

A new species, Eugenia marambaiensis M.C.Souza & M.P.Morim, is described and illustrated. It is characterized by having large translucent gland dots densely distributed on the leaves, with a caudate apex and slightly wavy margins and a glabrous raceme, with only two flowers. Eugenia marambaiensis was only found in the locality of Restinga da Marambaia, Rio de Janeiro, Brazil. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158 , 306–308.     

Isolation and characterization of polymorphic microsatellite loci for the horn fly, Haematobia irritans (L.) (Diptera: Muscidae)

The horn fly, Haematobia irritans (L.) (Diptera: Muscidae), is a cosmopolitan livestock pest that has caused a great negative impact on the animal production sector throughout the world. Here, we describe 10 polymorphic microsatellite loci isolated from H. irritans. The number of alleles found ranged from two to eight per locus and the expected heterozygosity from 0.1421 to 0.7702. These loci are potentially useful for the fine-scale genetic characterization of horn fly populations and provide fundamental information for pest management and planning of control programs.