Production of Ricinoleic Acid from Castor Oil by Immobilised Lipases

Abstract

Porcine pancreatic lipase (PPL), Candida rugosa lipase (CRL), and Castor bean lipase (CBL) were immobilized on celite by deposition from aqueous solution by the addition of hexane. Lipolytic performance of free and immobilized lipases were compared and optimizations of lipolytic enzymatic reactions conditions were performed by free and immobilized derivatives using olive oil as substrate. Afterwards, the influence on lipolysis of castor oil of free lipases and immobilized lipase derivatives have been studied in the case of production of ricinoleic acid. All of the lipases performances were compared and enzyme derivative was selected to be very effective on the production of ricinoleic acid by lipolysis reaction. Various reaction parameters affecting the production of ricinoleic acid were investigated with selected the enzyme derivative.

The maximum ricinoleic acid yield was observed at pH 7–8, 50°C, for 3 hours of reaction period with immobilized 1,3-specific PPL on celite. The kinetic constants K_m and V_max were calculated as 1.6 × 10^?4 mM and 22.2 mM from a Lineweaver–Burk plot with the same enzyme derivative. To investigate the operational stability of the lipase, the three step lipolysis process was repeated by transferring the immobilized lipase to a substrate mixture. As a result, the percentange of conversion after usage decreased markedly.     

河狸亲缘信息素的遗传力:遗传关系的信息是怎样编码的?

本研究利用几种亲缘关系对河狸 (Castorcanadensis)肛腺分泌物中的单个化合物和其整体组合的狭义遗传力进行了估算。使用气相色谱和质谱对河狸肛腺化合物进行定性和定量分析 ,发现了单个化合物的遗传力很低 ,但化合物的整体组合却显示有适度的遗传力。因此 ,我们认为亲缘关系的编码可能涉及多种化合物 ,并以数量和数字编码并用的方式进行     

Intraspecific variability of beaver teeth (Castoridae: Rodentia)

The metric variability of the teeth of Castor fiber Linné, 1758 and Castor canadensis Kuhl, 1820 with age are assessed. The ages of the studied specimens of C. fiber range from about 2 months to 16–17 years. Measurements of all teeth are given, and show a large range of size variation over all ages. The greatest size ranges can be observed for incisors, premolars, and third molars. Size variations of the fossil beavers Steneofiber eseri v. Meyer, 1846, Steneofiber castorinus Pomel, 1847, Anchitheriomys suevicus Schlosser, 1884, and Trogontherium cuvieri Fischer de Waldheim, 1809 are compared with those of C. fiber, and are of the same range and magnitude. It seems that it is nearly impossible to age beavers exactly with non‐invasive methods on the basis of tooth morphology, namely by the form and pattern of enamel islands on the chewing surface of the cheek teeth. Therefore, in conclusion, it is suggested that the observed variability in the size of fossil beaver teeth should be interpreted as changes with age in accordance with the overall size range in C. fiber. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 926–936.     

Rats are not the only introduced rodents producing ecosystem impacts on islands

In addition to rats, nutria (Myocastor coypus) and the North American beaver (Castor canadensis) have certainly caused damage at an ecosystem level when introduced to islands, in both cases primarily by ecosystem engineering. Of other introduced rodents successfully established on islands, the gray squirrel (Sciurus carolinensis) may be in the process of damaging entire forest ecosystems, particularly by bark-stripping. Though introduced muskrats (Ondatra zibethicus) have had ecosystem-level impacts in continental Europe, their impact on islands worldwide to which they have been introduced has been very limited. The North American red squirrel (Tamiasciurus hudsonicus) and Barbary ground squirrel (Atlantoxerus getulus) have each had substantial impacts when introduced to particular islands, but for neither species have these impacts yet been demonstrated to spread through an entire ecosystem. Introduced house mice (Mus musculus) may well generate ecosystem impacts on remote islands lacking rats, and it is possible that explosions of house mice on islands after rat eradication, a common occurrence, will lead in some instances to ecosystem impacts.     

Stakeholder Norms Toward Beaver Management in Massachusetts

ABSTRACT In Massachusetts, USA, both human and beaver (Castor Canadensis) population levels are increasing, beaver damage complaints are escalating, and beaver management options are restricted by the 1996 Wildlife Protection Act. We looked at the public's norms toward beavers in Massachusetts. In 2002 we sent a mail-back questionnaire to a random sample of 5,563 residents in 3 geographic regions in Massachusetts and to residents who submitted a beaver complaint to Massachusetts Division of Fisheries and Wildlife (MassWildlife) in 1999–2000 (47.3% overall response rate). Respondents supported some form of beaver management. As severity of beaver damage was perceived to increase, respondents were more willing to accept lethal management and control of beavers. These results emphasize the importance of how tolerance and acceptability of wildlife are influenced by the type of activity the animal is engaged in, the type of management action that is proposed, the positive or negative perception of a species in the eye of the public, and the public's preference for future population levels. A full understanding of these 4 points will help tailor management accordingly, because this knowledge can define a threshold of acceptance by the public for anticipated management actions. Restoration of full beaver management authority to the cognizant wildlife management agency would facilitate application of normative information to determine appropriate management response for minimizing conflicts between humans and beavers.     

Habitat conditions at beaver settlement sites: implications for beaver restoration projects

Recognition that beavers are integral components of stream ecosystems has resulted in an increase in beaver‐mediated habitat restoration projects. Beaver restoration projects are frequently implemented in degraded stream systems with little or no beaver activity. However, selection of restoration sites is often based on habitat suitability research comparing well‐established beaver colonies to unoccupied stream sections or abandoned colonies. Because beavers dramatically alter areas they occupy, assessing habitat conditions at active colonies may over‐emphasize habitat characteristics that are modified by beaver activity. During 2015–2017, we conducted beaver activity surveys on streams in the upper Missouri River watershed in southwest Montana, United States, to investigate habitat selection by beavers starting new colonies in novel areas. We compared new colony locations in unmodified stream segments to unsettled segments to evaluate conditions that promoted colonization. Newly settled stream segments had relatively low gradients (β ± SE = ?0.72 ± 0.27), narrow channels (β = ?1.31 ± 0.46), high channel complexity (β = 0.76 ± 0.42), high canopy cover of woody riparian vegetation (β = 0.56 ± 0.21), and low‐lying areas directly adjacent to the stream (β = 0.36 ± 0.24), where β denotes covariate effect sizes. Habitat selection patterns differed between our new settlement site analysis and an analysis of occupied versus unoccupied stream segments, suggesting that assessing habitat suitability based on active colonies may result in misidentification of suitable site conditions for beaver restoration. Our research provides recommendations for beaver restoration practitioners to select restoration sites that will have the highest probability of successful colony establishment.     

Selective foraging on woody plant species by the Eurasian beaver (Castor fiber) in Telemark, Norway

Beavers Castor spp. are generalist herbivores, feeding on the bark, shoots and leaves of woody plants, terrestrial herbs and forbs, ferns and aquatic vegetation. As central-place foragers, beavers move out from water to select and cut trees and vegetation, and then transport it back to their refuge. These terrestrial forays are energetically costly; therefore, beavers should concentrate their foraging activity near the central place and increase the degree of selectivity for specific sizes or species of food with increasing distance from the water. The aim of this study was to test the predictions of the central place and the optimal foraging theories for the food selection of the Eurasian beaver Castor fiber , and show the foraging preferences of the focal species in the boreal conifer forest zone of Europe. Foraging intensity by beavers and the abundance of woody species were surveyed in transects positioned randomly at seven beaver territories. In compliance with the central-place foraging theory, the foraging intensity declined with increasing distance from the river. Beavers fed preferentially on willows ( Salix ), rowan ( Sorbus ) and birches ( Betula ), although alders ( Alnus ) dominated their diet. Size selectivity showed similar patterns to previous North American studies, which were also carried out in habitats with predominantly small saplings. The probability of selection of small saplings dropped as distance increased, which is consistent with the predictions of optimal foraging models that larger prey items are more likely to be favoured with increasing provisioning distance.     

Differential cytokinin effects on the stimulation of in vitro shoot proliferation from meristematic explants of castor (Ricinus communis L.)

A highly efficient and reproducible method of in vitro propagation using meristematic explants has been developed for castor. Embryo axes and shoot tips were cultured on Murashige and Skoog (MS) medium supplemented with 0.5–10.0 mg/l of adenine, N⁶-benzyladenine (BA), kinetin (Kn), thiadiazuron (TDZ) and zeatin. TDZ (1.0–10.0 mg/l) gave the maximum number of shoots (37.8–40.0) from embryo axes, while BA (2.0 mg/l) was found superior to other cytokinins for obtaining the highest number of shoots (46.7) from the shoot apex. Adenine and Kn at all of the tested concentrations resulted in low proliferation rates from embryo axes. The carryover effect of the cytokinins was tested by subculturing proliferating shoot cultures from various media onto the medium fortified with 0.5 mg/l BA. There was no significant influence of the cytokinins on subsequent proliferation from the two explant types except for TDZ with embryo axes. The number of shoots from TDZ-habituated embryo axes ranged between 36.0 and 81.7, while it varied from 5.7 to 22.0 and 3.7 to 28.3 in axillary buds and embryo axes, respectively, on the other media. For elongation of shoots, gibberellic acid (GA₃) (0.1–1.0 mg/l) was added to the medium supplemented with 0.2–0.5 mg/l BA. Incorporation of GA₃ (0.1 mg/l) significantly enhanced the frequency of elongated shoots but drastically reduced the multiplication ability. Hence, proliferating shoot clusters were periodically transferred to the medium supplemented with 0.5 and 0.2 mg/l BA for further multiplication and elongation. Well-developed shoots were rooted on half-strength MS medium supplemented with 1.0 mg/l indole-3-butyric acid. The rooted plantlets were acclimatized with more than 60% success. Received: 17 June 1997 / Revision received: 3 September 1997 / Accepted: 20 September 1997     

Castor and camphor essential oils alter hemocyte populations and induce biochemical changes in larvae of Spodoptera littoralis (Boisduval) (Lepidoptera: Noctuidae)

Two plant essential oils; camphor and castor were tested for insecticidal and antifeedant activity against the 4th instar larvae of Spodoptera littoralis, a serious pest on cotton in Egypt. Also the impact of LC₁₀ of both oils on some physiological parameters in larvae was studied by using leaf dipping technique. Analysis of both oils using GC–MS revealed several insecticidal and antifeedant compounds. Our results showed higher insecticidal activity and antifeedant index of camphor oil against S. littoralis. The LC₅₀ and the antifeedant indices were 163.1, 246.8?mg/ml and 12.69, 6.62% for camphor and castor bean oil, respectively. The total hemocyte count (THC) and differential hemocyte count (DHC) were reduced significantly after 48?h of treatment compared to controls. Both oils reduced all types of hemocytes except plasmatocytes which were reduced only by castor oil. Camphor oil decreased total proteins and carbohydrates while castor oil targeted only carbohydrate content. Both oils didn't affect the amount of total lipids. Lipase, α-amylase and glucose-6-phosphate dehydrogenase (G6PD) enzyme activities were increased significantly in larvae treated with camphor oil than other treatments. These results clearly indicate that castor and camphor oils can affect the nutritional status in S. littoralis larvae, thereby changing the internal metabolic processes in the larvae which make them as potential control agents in IPM programs against S. littoralis.