In vitro erythrocytic membrane effects of dibenzyl trisulfide, a secondary metabolite of Petiveria alliacea     

D.J. Pepple  A.A. Richards  D.A. Lowe  W.A. Reid  N.O. Younger  L.A.D. Williams 《Fitoterapia》2010,81(8):1113-1116

We investigated the in vitro effect of dibenzyl trisulfide (DTS), a secondary metabolite of Petiveria alliacea, on erythrocyte elasticity, relaxation time and membrane morphology. Blood samples from 8 volunteers with hemoglobin AA were exposed to 100, 200, 400, 800 and 1000 ng/ml of DTS respectively and the elasticity and relaxation time measured. There were statistically significant, dose-dependent increases in elasticity and relaxation times. The changes in membrane morphology observed also increased with increased concentration of DTS. This suggests that DTS interaction with membrane protein resulted in increased elasticity, relaxation time and deformation of the erythrocyte membrane.  相似文献   

Effects of Cultivation after Planting on Yields of Seed Cotton     

P. V. M. Richards  P. E. L. Thomas 《国际虫害防治杂志》2013,59(4):484-485

Abstract

Experiments carried out over several seasons showed that, on a soil prone to crusting, cultivations after the establishment of a cotton crop only increased yields in a season of low rainfall. This yield increase appeared to have been due to enhanced entry into the soil of the limited effective rainfall. In one season of high rainfall, deep cultivation significantly reduced yields.  相似文献   

Notes on the Vegetative Propagation of Cacao by Cuttings     

D. A. Richards 《The Journal of Horticultural Science and Biotechnology》2013,88(3):192-199

Many investigations at the West African Cacao Research Institute require the production of uniform clones of cacao. Although Amelonado, which is the name adopted for the most predominant variety of cacao in West Africa, appears to be genetically uniform, it has been considered advisable to use self-rooted clones for such detailed work as the definition of virus symptomatology. Also many of the Institute’s disease and pest resistant selections are known to be heterozygous types of cacao, and investigations on these must of necessity be carried out on clonal material. Cacao can be rapidly propagated by budding, but this method introduces the variability associated with seedling rootstocks.  相似文献   

Anti-biofilm compounds derived from marine sponges     

Stowe SD  Richards JJ  Tucker AT  Thompson R  Melander C  Cavanagh J 《Marine drugs》2011,9(10):2010-2035

Bacterial biofilms are surface-attached communities of microorganisms that are protected by an extracellular matrix of biomolecules. In the biofilm state, bacteria are significantly more resistant to external assault, including attack by antibiotics. In their native environment, bacterial biofilms underpin costly biofouling that wreaks havoc on shipping, utilities, and offshore industry. Within a host environment, they are insensitive to antiseptics and basic host immune responses. It is estimated that up to 80% of all microbial infections are biofilm-based. Biofilm infections of indwelling medical devices are of particular concern, since once the device is colonized, infection is almost impossible to eliminate. Given the prominence of biofilms in infectious diseases, there is a notable effort towards developing small, synthetically available molecules that will modulate bacterial biofilm development and maintenance. Here, we highlight the development of small molecules that inhibit and/or disperse bacterial biofilms specifically through non-microbicidal mechanisms. Importantly, we discuss several sets of compounds derived from marine sponges that we are developing in our labs to address the persistent biofilm problem. We will discuss: discovery/synthesis of natural products and their analogues-including our marine sponge-derived compounds and initial adjuvant activity and toxicological screening of our novel anti-biofilm compounds.  相似文献   

Adiposity and adiponectin in dogs: investigation of causes of discrepant results between two studies     

Verkest KR  Rose FJ  Fleeman LM  Rand JS  Morton JM  Richards AA  Ishioka K  Whitehead JP 《Domestic animal endocrinology》2011,41(1):35-41

Although one study showed lower adiponectin concentrations in obese dogs, other recent studies indicate that adiponectin might not be decreased in obese dogs, raising the possibility that the physiology of adiponectin is different in dogs than in humans. The aim of this study was to investigate possible causes of the discrepancy between the two largest studies to date that assessed the association between adiposity and adiponectin concentration in dogs, including the validity of the assay, laboratory error, and the effects of breed, sex, and neuter status on the relationship between adiposity and adiponectin concentrations. Adiponectin concentrations measured with a previously validated adiponectin ELISA were compared with those estimated by Western blotting analysis of reduced and denatured plasma samples. The possibility of laboratory error and the effect of EDTA anticoagulant and aprotinin were tested. Adiponectin concentration was measured by ELISA in 20 lean dogs (10 male and 10 female, 5 neutered in each sex). There was close correlation between adiponectin concentrations measured by ELISA and those estimated by Western blotting analysis (r = 0.90; P < 0.001). There was no substantial effect of EDTA, aprotinin, or laboratory error on the results. There was confounding by neuter status of the relationship between adiposity and adiponectin concentrations, but adiponectin concentrations were not significantly lower in male than in female lean dogs (females, 36 mg/L; males, 26 mg/L; P > 0.20) and were not significantly lower in intact than in neutered lean male dogs (intact, 28 mg/L; neutered, 23 mg/L; P = 0.49). We conclude that the adiponectin ELISA previously validated for use in dogs appears to be suitable for determination of canine adiponectin concentrations and that testosterone does not appear to have a strong effect on plasma adiponectin concentrations in dogs. Obesity might decrease adiponectin concentrations in intact but not in neutered dogs.  相似文献   

Rumen temperature change monitored with remote rumen temperature boluses after challenges with bovine viral diarrhea virus and Mannheimia haemolytica     

Rose-Dye TK  Burciaga-Robles LO  Krehbiel CR  Step DL  Fulton RW  Confer AW  Richards CJ 《Journal of animal science》2011,89(4):1193-1200

Remote rumen temperature monitoring is a potential method for early disease detection in beef cattle. This experiment was conducted to determine if remotely monitored rumen temperature boluses could detect a temperature change in steers exposed to bovine viral diarrhea virus (BVDV) and challenged with a common bovine respiratory disease pathogen, Mannheimia haemolytica (MH). Twenty-four Angus crossbred steers (BW = 313 ± 31 kg) were allotted to 1 of 4 treatments: 1) no challenge (control); 2) challenge by a 72-h exposure to 2 steers persistently infected with BVDV; 3) bacterial challenge with MH; and 4) viral challenge by a 72-h exposure to 2 steers persistently infected with BVDV followed by bacterial challenge with MH (BVDV + MH). Remotely monitored rumen temperature boluses programmed to transmit temperature every minute were placed in the rumen before the time of exposure to steers persistently infected with BVDV. Rectal temperatures were taken before MH challenge (0) and at 2, 4, 6, 12, 18, 24, 36, 48, 72, and 96 h after MH challenge. Rumen temperatures were recorded 3 d before (-72 h; period of BVDV exposure) through 14 d after (336 h) MH challenge. Rumen temperatures were analyzed as a randomized complete block design with a 2 × 2 factorial arrangement of treatments and a first-order autoregressive covariance structure for repeated measures. A treatment × day interaction was observed for average daily rumen temperature (P < 0.01). A treatment difference (P < 0.01) was observed on d 0, when MH-challenged steers had greater rumen temperatures than steers not challenged with MH. There was no BVDV × day interaction (P > 0.01). Rumen temperatures averaged every 2 h resulted in a BVDV × hour interaction (P < 0.01) and an MH × hour interaction (P < 0.01). The BVDV × hour differences occurred at h -18 to -14, 40 to 46, 110, 122, and 144 to 146 (P < 0.01). The MH × hour difference occurred at h 4 to 24 (P < 0.01). Maximum rumen temperature was increased (P < 0.01) for BVDV (0.8 °C), MH (1.2 °C), and BVDV + MH (1.3 °C) compared with the control. On average, rumen temperatures measured by the boluses at the same time points as the rectal temperatures were 0.13 °C less than rectal temperatures, and the 2 body temperatures were highly correlated (r = 0.89). Rumen temperature boluses appear to have potential as a tool for detecting temperature changes associated with adverse health events such as exposure to bovine respiratory disease and BVDV.  相似文献   

Genetic diversity of diploid Japanese strawberry species based on microsatellite markers     

Wambui Njuguna  Kim E. Hummer  Christopher M. Richards  Thomas M. Davis  Nahla V. Bassil 《Genetic Resources and Crop Evolution》2011,58(8):1187-1198

The United States Department of Agriculture (USDA)—Agricultural Research Service (ARS)—National Clonal Germplasm Repository (NCGR) in Corvallis, Oregon, is a genebank that preserves strawberry genetic resources. Representatives of two Japanese diploid species, Fragaria iinumae Makino and F. nipponica Makino were collected for conservation by the NCGR during an expedition to Hokkaido, Japan. Fragaria iinumae may be a genome contributor to the cultivated octoploid strawberries. The objective of this study was to evaluate the genetic diversity of these two species by using simple sequence repeat (SSR) markers. Twenty of 82 Fragaria-derived SSRs, polymorphic among and within the two species, were selected for genetic analysis of 137 accessions. Genetic diversity, based on the proportion of shared alleles between the two species, in F. nipponica (0.4542) and F. iinumae (0.1808) was significantly different. Three wild interspecific hybrids were identified from intermediate memberships in the two diploid species groups revealed by using the clustering program, Structure. Principal coordinate analysis followed by non-parametric modal clustering (PCO-MC) grouped accessions into two clusters representing the two diploid species. Further clustering within the species groups generated with the program, STRUCTURAMA^TM, resulted in seven subclusters in F. iinumae and three in F. nipponica, which may represent breeding populations appropriate for clonal conservation. Long-term preservation of the species populations and the limited number of hybrids on the island is discussed relative to their geographical distribution and the geological history of Hokkaido Island.  相似文献   

Report of potato nutrition (fertilization) committee     

Arthur Hawkins  O. A. Lorenz  N. R. Richards  L. M. Ware  G. V. C. Houghland 《American Journal of Potato Research》1959,36(2):73-75

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Analysis of genetic diversity in a collection of Plantago species: application of ISSR markers     

Bagheri  Motahareh  Heidari  Bahram  Dadkhodaie  Ali  Heidari  Zahra  Daneshnia  Negar  Richards  Christopher M. 《Journal of Crop Science and Biotechnology》2022,25(1):1-8

Journal of Crop Science and Biotechnology - The analysis of genetic diversity in medicinal plant species can greatly facilitate germplasm conservation and selection for use in breeding schemes. The...  相似文献   

Integrating new soybean varieties for soil fertility management in smallholder systems through participatory research: Lessons from western Kenya     

M. Misiko  P. Tittonell  J.J. Ramisch  P. Richards  K.E. Giller 《Agricultural Systems》2008,97(1-2):1-12

The aim of this paper was to understand the process of selecting soybean (Glycine max [L.] Merr.) promiscuous varieties by smallholders for soil fertility management in western Kenya. Eight varieties were screened on 2.5 m × 3 m plots that were managed according to farmers’ practices and evaluated through participatory monitoring and evaluation approaches. Farmers selected preferred varieties and explained their reasons (criteria) for making the selections. Seven promiscuous varieties had better yields than a local one. Farmers’ selection criteria fell into three broad categories relating to yield, appearance and labour. Selection criteria were not primarily aimed to improve soil fertility. This created a challenge to embed the new varieties within the local farming systems for soil fertility improvement. This study shows that farmer criteria for selecting varieties overlapped with scientific procedures. We propose co-research activities targeted to strengthen farmer experimentation skills, their understanding on N addition, and the role of P.  相似文献