Detection and Characterization of the Cumulene Carbenes H2C5 and H2C6

Two cumulene carbenes, H2C5 and H2C6, were detected in a supersonic molecular beam by Fourier transform microwave spectroscopy. Their rotational and leading centrifugal distortion constants were determined with high accuracy, such that the entire radio spectrum can now be calculated. Like the known carbenes H2C3 and H2C4, both molecules have singlet electronic ground states and linear carbon-chain backbones. They can be produced in sufficiently high concentrations in the laboratory that their electronic spectra, expected to lie in the visible, should be readily detectable by laser spectroscopy. The microwave spectra of other, more exotic isomers may be detectable as well.     

ELISA在苏云金杆菌杀虫蛋白毒素检测中的应用及新进展

苏云金杆菌是目前应用较广泛的生物杀虫细菌之一，其产生的杀虫蛋白毒素是主要的杀虫成分，目前对苏云金杆菌的毒力和杀虫蛋白毒素的检测主要采用生物测定、SDS-PAGE等方法，但这些方法的灵敏度较差。本文综述了酶联免疫吸附分析法在苏云金杆菌蛋白毒素检测中的应用，以及在检测中采用的ELISA的类型和基本原理，并对其应用前景进行了展望。     

球孢白僵菌生长及毒力影响因子的研究进展

随着害虫综合治理的提出，昆虫病原真菌在防治农林害虫上的应用日趋广泛，白僵菌是世界各国研究应用最多的真菌杀虫剂。从白僵菌生长所需的营养、温湿度条件等方面的研究进展进行阐述，总结了提高菌株生长水平和杀虫效果的主要措施，以期对今后白僵菌的培养及应用提供参考。     

Anatomy of a dinosaur—Clarification of vertebrae in vertebrate anatomy

The flat-end surfaces of dinosaur vertebral centra led to the presumption that intervertebral discs occupied the space between their vertebrae. A set of fused hadrosaur vertebrae allowed that hypothesis to be tested. The Tyrannosaurus rex responsible for this pathology did not escape unscathed. It left behind a tooth crown that had fractured. Fragments of that tooth were scattered through the intervertebral space, evidencing that there was no solid structure to impede its movement. That eliminates the possibility of an intervertebral disc and instead proves the presence of an articular space, similar to that in modern reptiles, but at variance to what is noted in birds. While avian cervical vertebral centra appear to be separated by diarthrodial joints, the preponderance of their thoracic vertebral centra is not separated by synovial joints.     

The ecology and pathobiology of Clostridium difficile infections: an interdisciplinary challenge

Clostridium difficile is a well recognized pathogen of humans and animals. Although C. difficile was first identified over 70 years ago, much remains unknown in regards to the primary source of human acquisition and its pathobiology. These deficits in our knowledge have been intensified by dramatic increases in both the frequency and severity of disease in humans over the last decade. The changes in C. difficile epidemiology might be due to the emergence of a hypervirulent stain of C. difficile, ageing of the population, altered risk of developing infection with newer medications, and/or increased exposure to C. difficile outside of hospitals. In recent years, there have been numerous reports documenting C. difficile contamination of various foods, and reports of similarities between strains that infect animals and strains that infect humans as well. The purposes of this review are to highlight the many challenges to diagnosing, treating, and preventing C. difficile infection in humans, and to stress that collaboration between human and veterinary researchers is needed to control this pathogen.     

Chalk and chalk debris as a medium for plant growth, with particular reference to Channel Tunnel spoil

Abstract. Four lithological types of chalk are recognized. Normal white chalk has 34–50% porosity, nearly all of which holds water conventionally'available'to plants. Hard chalk and grey chalk have less porosity and available water; chalk marl has very little available water. Significant capillary rise from below the root zone can be expected in normal white chalk only, and is not halted by fragmentation. Chalk has little N and usually little P. Only grey chalk and chalk marl have much ettractable K and Mg. These also slake, impeding roots. Thus, fertilized plants tolerant of high pH can grow well on normal white chalk debris, but on raw chalk marl, e.g. Channel Tunnel spoil, they need irrigation. Interesting plants volunteer on chalk debris, even on slaked chalk marl by the sea.     

Locomotor effects in sheep of alkaloids identified in Australian Tribulus terrestris

Fresh, mature, ungrazed Tribulus terrestris plant material was subjected to a standard alkaloid extraction procedure. The extract was fractionated by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Two major alkaloid fractions were demonstrated. These fractions were identified by means of TLC, ultraviolet spectrofluorimetry (UVS) and HPLC, as the beta-carboline indoleamines harmane and norharmane. The extractable alkaloid content was determined to be 44 mg/kg dry matter. Synthetic harmane and norharmane were administered subcutaneously to sheep at a dose rate of 54 mg/kg. Both compounds caused similar nervous effects. The main effect observed was limb paresis, which in some sheep was body side blased. The clinical signs observed in the experimental sheep were consistent with those described for naturally occurring cases of Tribulus terrestris staggers. It was proposed that harmane and norharmane accumulate in tryptamine-associated neurones of the central nervous system, during months of tribulus ingestion, and gradually interact irreversibly with a specific neuronal gene DNA sequence.     

Economic and financial model to the mass-rearing of Macrolophus pygmaeus (Rambur) (Heteroptera: Miridae), a biological control agent against the tomato moth Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in protected culture

BACKGROUND

Tuta absoluta (Meyrick) is a major pest of tomato produced in glasshouses and open field, causing severe damages to crops, reducing the quality of tomato fruits. The current maintenance of the pest populations below the economic threshold is not achieved by natural and classical control, thus requiring the continuous application of biological control agents (BCAs), under an augmentative or inoculative approach. The present study aims to develop an economic and financial model to evaluate the commercial viability of a continuous mass production of Macrolophus pygmaeus (Rambur), a BCA commonly used against the tomato moth, Tuta absoluta, in protected culture. The estimations for our model were based on two approaches: the farm-level impact analysis and the benefit–cost analysis.

RESULTS

The results of the farm-level analysis show that the adoption of a more sustainable biological control approach is profitable for farmers and the benefit–cost analysis provides evidence that the investment on a new factory dedicated to the mass rearing of M. pygmaeus to control tomato moth populations generates a positive net present value (NPV) of 7.2 million euros, corresponding to an internal rate of return (IRR) of 28.4% per year.

CONCLUSION

Our results are in line with (i) the more recent European Commission proposals for a new Regulation on sustainable use of plant protection products, which includes the reduction of 50% the use and risk of chemical pesticides by 2030 and (ii) most of the existing literature which conclude that new projects on BCA production are worth investments. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.