中国鲎保育工作研究进展

近年来中国鲎种群数量呈急剧下降,资源几近枯竭,如何有效开展其保育工作成为研究热点。从中国鲎的地理分布、生活习性、资源价值、保育工作开展现状、保育措施等5个方面对中国鲎资源现状以及其保育工作开展情况进行概括,为完善中国鲎保育工作提供最新资料。     

Points, patches, and regions: scaling soil biogeochemical patterns in an urbanized arid ecosystem

Cities are rapidly growing throughout the world and are altering biologic processes in many regions, with global consequences. Urbanization in the Phoenix, USA metropolitan region has dramatically altered regional ecosystem patterns, but little is known about how these changes have influenced soil organic matter, total nitrogen, and the distribution of nitrogen stable isotopes. Because urban development is a phenomenon occurring at multiple scales, ecological consequences of urbanization will likely differ between individual patches and the entire metropolitan region. To investigate such changes we conducted spatially explicit surveys including three dominant land‐use types in this region: native desert, agriculture, and mesic residential. These data were combined for analysis with previously collected samples from a synoptic regional survey. A landscape scaling approach was implemented to compare the dependence of soil variability on the sampled extent and the uncertainty associated with scaling from points to patches, land‐use types, and the Phoenix metropolitan region. The multiple‐scale analysis of soil properties showed that variation in total soil nitrogen, soil organic matter, and δ⁵N content of soils differed between patch and regional scales. The majority of variation in the urbanized patch types was exhibited between patches while for the native desert the majority of variation was observed within individual patches. These differences show the impact of urbanization on the scaling relations of ecosystem components. Overall, urbanization in this region appears to have increased soil organic matter by 44%, total nitrogen by 48%, and has elevated δ¹⁵N by 21%.     

The infinitesimal, the deterministic, and the probabilistic: Alternate container inspection policies in invasive species management

Recently, Batabyal and Nijkamp (2005, Stochastic Environmental Research and Risk Assessment 19: 340–347) have shown that in an inspection cycle, regardless of whether the inspection policy choice is made on the basis of an optimization exercise or on the basis of a rule of thumb, the “container policy” dominates the “temporal policy” because the former results in lower long run expected net cost (LRENC) from inspections. In this paper, we continue this line of inquiry and analyze container policies in three scenarios. In the first scenario the time taken to conduct inspections is negligible. In the second scenario, this inspection time is deterministic and in the third scenario this inspection time is stochastic. Specifically, we compare and contrast the LRENC and the optimal container policy in each of these three scenarios.      

Hydrogen bonding markedly reduces the pK of buried carboxyl groups in proteins

The ionizable groups in proteins with the lowest pKs are the carboxyl groups of aspartic acid side-chains. One of the lowest, pK=0.6, is observed for Asp76 in ribonuclease T1. This low pK appeared to result from hydrogen bonds to a water molecule and to the side-chains of Asn9, Tyr11, and Thr91. The results here confirm this by showing that the pK of Asp76 increases to 1.7 in N9A, to 4.0 in Y11F, to 4.2 in T91V, to 4.4 in N9A+Y11F, to 4.9 in N9A+T91V, to 5.9 in Y11F+T91V, and to 6.4 in the triple mutant: N9A+Y11F+T91V. In ribonuclease Sa, the lowest pK=2.4 for Asp33. This pK increases to 3.9 in T56A, which removes the hydrogen bond to Asp33, and to 4.4 in T56V, which removes the hydrogen bond and replaces the -OH group with a -CH(3) group. It is clear that hydrogen bonds are able to markedly lower the pK values of carboxyl groups in proteins. These same hydrogen bonds make large contributions to the conformational stability of the proteins. At pH 7, the stability of D76A ribonuclease T1 is 3.8 kcal mol(-1) less than wild-type, and the stability of D33A ribonuclease Sa is 4.1 kcal mol(-1) less than wild-type. There is a good correlation between the changes in the pK values and the changes in stability. The results suggest that the pK values for these buried carboxyl groups would be greater than 8 in the absence of hydrogen bonds, and that the hydrogen bonds and other interactions of the carboxyl groups contribute over 8 kcal mol(-1) to the stability.     

Effect of black cumin (Nigella sativa) on heart rate, some hematological values, and pancreatic β-cell damage in cadmium-treated rats

This study was designed to investigate the effect of Nigella sativa (NS) on the heart rate, some hematological values, and pancreatic β-cell damage in cadmium (Cd)-treated rats. The rats were randomly grouped into one of three experimental groups: Control, Cd treated, and Cd+NS treated. Each group contained 10 animals. The Cd-treated and Cd+NS-treated groups were injected subcutaneously daily with CdCl₂ dissolved in isotonic NaCl in the amount of 2 mL/kg for 30 d, resulting in a dosage of 0.49 mg Cd/kg/d. The control group was injected with only isotonic NaCl (2 mL/kg/d) throughout the experiment (for 30 d). Three days prior to administration of CdCl₂, the Cd+NS-treated group received the daily intraperitoneal (ip) injection of 2 mL/kg NS until the end of the study; animals in all three groups were fasted for 12 h and blood samples were taken for the determination of the glucose and insulin levels, red blood cell (RBC) and white blood cell (WBC) counts, packet cell volume (PCV), and hemoglobin (Hb) concentration. The heart rates of rats were also measured by a direct writing electrocardiograph before the blood withdrawals. It was found that NS treatment increased the lowered insulin levels, RBC and WBC counts, PCV, and neutrophil percentage in Cd-treated rats. However, the WBC count of Cd-treated rats with NS treatment was still lower than those of control values. NS treatment also decreased the elevated heart rate and glucose concentration of Cd-treated rats. Pancreatic tissues were also harvested from the sacrificed animals for morphological and immunohistochemical examinations. Cd exposure alone caused a degeneration, necrosis, and weak degranulation in the β-cells of the pancreatic islets. In Cd+NS-treated rats, increased staining of insulin and preservation of islet cells were apparent. It is concluded that NS treatment might decrease the Cd-treated disturbances on heart rate, some hematological values, and pancreatic β-cell.     

略论中国园林观赏昆虫的美学价值

对中国园林中栖息于不同植物群落的观赏昆虫主要类群及其美学价值进行了初步探析;简析了审美意识与审美主体及时空的关系;并对如何进一步能动地利用观赏昆虫去丰富、补缀、显豁园林的美学价进行了探讨。     

Incorporating Science,Technology, Fairness,and Accountability in Environmental,Health, and Safety Decisions

The Precautionary Principle is in sharp political focus today because (1) the nature of scientific uncertainty is changing and (2) there is increasing pressure to base governmental action on more “rational” schemes, such as cost-benefit analysis and quantitative risk assessment, the former being an embodiment of ‘rational choice theory’ promoted by the Chicago school of law and economics. The Precautionary Principle has been criticized as being both too vague and too arbitrary to form a basis for rational decision making. The assumption underlying this criticism is that any scheme not based on cost-benefit analysis and risk assessment is both irrational and without secure foundation in either science or economics. This paper contests that view and makes explicit the rational tenets of the Precautionary Principle within an analytical framework as rigorous as uncertainties permit, and one that mirrors democratic values embodied in regulatory, compensatory, and common law. Unlike other formulations that reject risk assessment, this paper argues that risk assessment can be used within the formalism of tradeoff analysis—a more appropriate alternative to traditional cost-benefit analysis and one that satisfies the need for well-grounded public policy decision making. This paper will argue that the precautionary approach is the most appropriate basis for policy, even when large uncertainties do not exist, especially where the fairness of the distributions of costs and benefits of hazardous activities and products are a concern. Furthermore, it will offer an approach to making decisions within an analytic framework, based on equity and justice, to replace the economic paradigm of utilitarian cost-benefit analysis.     

On the Even Greater Need for Precaution Under Global Change

The greater the potential for disastrous, large-scale, or catastrophic impacts on health, the greater the case for precaution. The imperative for precautionary action, critical also for downstream determinants of health, is at least as compelling where macro-level concerns about the sustainability of life on Earth are at issue. In this context, I propose that a higher threshold of uncertainty is needed where large-scale harms to health and well-being are possible. Initial efforts must focus on the training of researchers and risk managers for competencies in complexity, and in systems approaches to transdisciplinary enquiry. Revisiting the intent behind Bradford Hill on causation is an essential first step. Focus on the more proximate causes of diseases, such as those related either to occupational exposures or to more downstream environmental exposures, is left to others in this collection.     

Age, sexual and seasonal differences of haematological values and antibody status to Chlamydophila sp. in feral and racing pigeons (Columba livia forma domestica) from an urban environment (Zagreb, Croatia)

The aim of this study was to determine the basic haematological parameters in feral and racing pigeons and to compare these parameters according to age, sex and season in healthy feral pigeons as well as between Chlamydophila-serologically positive and negative feral pigeons. Red blood cells (RBC), packed cell volume (PCV), haemoglobin (Hb), mean cell volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), white blood count (WBC), thrombocyte count and differential WBC, were determined in 366 pigeons (Columba livia forma domestica) captured in the City of Zagreb between 1999 and 2002. Of these, 232 feral (179 adult and 53 juvenile, 104 male and 75 female) and 57 racing pigeons (25 male and 32 female) were clinically healthy and bacteriologically and serologically negative, but 77 birds had antibody titres against Chlamydophila sp. Significantly lower values of RBC, PCV, Hb, MCH, WBC and thrombocyte (P<0.05) were observed in young compared to adult pigeons, while the differences in MCV and MCH were not significant between age classes. In differential WBC of young pigeons, a significantly higher percentage of heterophils, eosinophils, basophils and monocytes and a significantly smaller percentage of lymphocytes (P<0.01) was found than in adult pigeons. Significant sex-related differences were seen only in MCV values and in the percentage of lymphocytes (higher in females) and neutrophils (higher in males). PCV, Hb, MCV and MCH increased, while WBC decreased during wintertime (P<0.05). In differential WBC, percentage of heterophils was low in summer and autumn. At the same time, a higher percentage of basophils was found. Low numbers of monocytes were found in summer and low values of eosinophils in winter. In racing pigeons, values of eosinophils and basophils were significantly lower than in feral pigeons. Pigeons which had antibodies against Chlamydophila sp. possessed a higher percentage of monocytes and less lymphocytes than sero-negative animals, while WBC was significant lower than in sero-negative feral pigeons.     

Problem of distinguishing false-positive tests from acute or transient Helicobacter pylori infections

BACKGROUND: Reliable detection of acute Helicobacter pylori infections remains problematic. The high prevalence of false-positive non-invasive tests in low H. pylori prevalence populations makes identification of acute and transient infections difficult. METHODS: We explored the use of serum pepsinogens (PG) for diagnosis of acute infection in patients following H. pylori challenge such that the onset of the infection was known. We then compared those findings to a group of children with presumed acute infections defined as a positive urea breath test (UBT) and negative IgG serology. RESULTS: We examined the pattern and calculated cut-off values of PG levels in 18 adult volunteers with known acute H. pylori infection. We then compared the results with sera from nine symptomatic children with presumed acute H. pylori infection and a matched control group of nine children who did not meet criteria for acute H. pylori infection. In acute infection, both PGI and II levels increased following H. pylori infection reaching a peak by 2 weeks post-infection. The frequency of a positive test defined as a value > mean +2 SD was 17, 71, and 94% at week 1, 2, and 4 post-infection, respectively. Only one child with presumed acute H. pylori infection had an elevated serum PGI and one had an elevated PGII. Five of the children had follow-up UBTs and four were negative consistent with the diagnosis of false-positive UBT. H. pylori infection was confirmed in the child with an elevated PGI level. CONCLUSIONS: These data suggest that a single positive noninvasive test in populations of low prevalence is most likely a false-positive result. This suggests that a single positive test requires confirmation preferably using a test that measures a different parameter (e.g., UBT confirmed by stool antigen test). It appears that most "transient"H. pylori infections are diagnosed on the basis of false-positive tests. PG levels are possible candidates as the confirmatory test.