Castor beans hulls as a replacement for Tifton 85 hay in lamb diets

The objective of this study was to evaluate the effect of replacing Tifton 85 hay (0, 33, 66, or 100 %) with by castor bean hulls on the intake and nutrient digestibility and performance of 28 noncastrated lambs, averaging 7 months in age, 19.5?±?2.0 kg average live weight, fed on diets based on forage cactus. The animals were housed in individual pens for 100 days. The digestibility trial occurred 40 days after the start of the performance using LIPE® as an external indicator for estimating fecal dry matter production. The replacement of hay with Castor beans hulls linearly decreased the intakes of dry matter, neutral detergent fiber, organic matter, and crude protein and reduced the digestibility coefficients of the dry matter, neutral detergent fiber, organic matter content, crude protein, and total digestible nutrient content. The hot carcass and true carcass yields were not influenced by the treatments and the feed conversion increased linearly. The empty body weight, live weight at slaughter, hot and cold carcass weights, total gain, and average daily gain decreased linearly with the replacement. The replacement of Tifton 85 hay with castor bean hulls reduced the intake of dry matter, crude protein and energy, consequently reducing the performance of the animals. However, as the regression coefficients were of low magnitude, data were subjected to analysis of variance and means were compared using the Dunnett test with diet without castor bean hulls set as the control treatment. The Tifton 85 hay can be replaced up to 66 % by castor bean hulls in finishing diets for lambs.     

Knowledge and prevention of tickborne diseases among Hispanic and non‐Hispanic residents of Maryland and Virginia

Tickborne diseases (TBDs) such as Lyme disease (LD), babesiosis, ehrlichiosis and Rocky Mountain spotted fever cause substantial morbidity and even mortality in the USA. Data indicate that Hispanic populations may be at greater risk for occupational exposure to ticks and disseminated LD; however, information on knowledge and practices of Hispanic populations regarding TBDs is limited. We surveyed 153 Hispanic and 153 non‐Hispanic residents of Maryland and Virginia to assess awareness of TBDs, prevention practices and risk of tick encounters. Hispanic respondents were less likely than non‐Hispanics to report familiarity with LD symptoms (21% vs. 53%, p < 0.001) and correctly identify ticks as vectors of LD (40% vs. 85%, p < 0.001). Although there was no significant difference in overall proportion of respondents who routinely take one or more preventive measures to prevent tick bites (59% vs. 61%, p = 0.65), Hispanics were more likely to report showering after coming indoors (36% vs. 25%, p = 0.04) but less likely to conduct daily tick checks compared with non‐Hispanics (17% vs. 35%, p < 0.001). History of tick bite or finding a tick crawling on oneself or a household member in the past year did not significantly differ between Hispanics and non‐Hispanics (19% vs. 24%, p = 0.26). Notably, after controlling for Hispanic/non‐Hispanic ethnicity, primary language (English vs. Spanish) was a significant predictor of whether an individual had knowledge of LD symptoms, correctly identified ticks as vectors for LD and performed daily tick checks. These results provide guidance for future development of more targeted and effective TBD prevention education for both Hispanic and non‐Hispanic communities.     

Options for Management of Fusarium Wilt of Strawberry in California

ABSTRACT

The emergence of Fusarium wilt, caused by Fusarium oxysporum f. sp. fragariae, as a problem for strawberry production in California has been associated with delivery of fumigants to beds through drip-lines rather than flat-fumigation of an entire field. Our research shows that bed fumigation fails to eliminate propagules of the Fusarium wilt pathogen, which remain particularly abundant in bed shoulders at a depth of 30 cm. Controlled environment studies confirmed that inoculum at this depth could cause disease. Screening of currently grown strawberry cultivars documented a wide range of susceptibilities to Fusarium wilt, with some being highly resistant.     

Validating mammal monitoring methods and assessing the performance of volunteers in wildlife conservation—“Sed quis custodiet ipsos custodies ?”

Many conservation organisations rely heavily on volunteers, and the government often relies on them to achieve tasks for which funding is insufficient—for example, the monitoring of trends in biodiversity on a national scale. Thus, it is critical to deploy non-professionals effectively. In this study we validated and calibrated the data collected by 155 volunteers, assisting with mammal monitoring at Wytham Woods, Oxfordshire, between April 2000 and December 2001. Tasks included small mammal trapping and handling, surveying and censusing for badgers, estimating deer population sizes from dropping counts, and transect surveys for mammal field signs. We analysed the effects of age, gender, previous experience, physical fitness and aptitude on volunteer performance using quantitative measures and qualitative scores. We found that (1) techniques that could be taught to volunteers without lengthy or specialist training were sufficiently accurate to yield reliable data, (2) with approximately half a day of training in each task, volunteers could produce reliable data, verified by professionals, and (3) volunteer teams brought considerable time savings to many tasks, compared with a single professional researcher. Our analyses show that physical fitness was a significant predictor of a volunteer's ability to perform tasks well and, in our particular sample, a male-bias in volunteer aptitude was apparent in some tasks. Previous experience as a conservation volunteer did not enhance performance over that of novices nor did age have any effect on volunteers’ ability. The overall veracity of volunteer data compared well with data collected using more specialist methods or collected by professional researchers using the same method. Volunteers required more time per task and, while they showed a tendency to underestimate population sizes, their results were consistent. Additionally, the programme helped to raise the environmental awareness of volunteers and their understanding of woodland ecology.     

Do plant species of different resource qualities form dissimilar energy channels below-ground?

This study aimed at examining whether plant species of varying resource quality give rise to a fungal- or bacterial-based energy channel in the plants’ rhizosphere, when planted in soil, in which the plant species naturally occur. In an 18-month large-scale laboratory mesocosm experiment, two plant species (Holcus lanatus and Lotus corniculatus) producing labile litter and two plant species (Picea abies and Calluna vulgaris) producing recalcitrant litter were placed in the same mesocosm. This allowed the decomposer biota (microbes, protozoa, nematodes, collembolans, and enchytraeid worms) to freely choose their preferred plant rhizosphere. Because a fungal-based energy channel is in theory regarded to retain nutrients better in the soil than a bacterial-based energy channel, water was collected underneath the plant species and analyzed for its nutrient (N and P) content.In general, the number of soil biota groups responding significantly to the plant treatment increased with time. Soil microbes were the first group to react, but the ability of the plants to boost a clearly fungal- or bacterial-based energy channel was generally weak. However, at the end of the study, a higher fungal-to-bacterial biomass ratio was found beneath Calluna than beneath the other plant treatments. Of the secondary consumers, nematodes were the most responsive group, with total number and especially plant parasites being more abundant beneath Lotus than beneath Picea and Calluna indicating a root-based energy channel to persist under the legume. Protozoa, enchytraeid worms and collembolans responded weakly and inconsistently to plant treatment. Liberation of plant-available nutrients was plant-dependent. Towards the end of the study, less nitrate and phosphate leached through the Picea soils than through the control, which indicates a more effective nutrient retention to take place under this plant species. We found that plant species can, in a relatively short time, modify the composition of the soil decomposer community. However, no consistent evidence for the plant–soil systems developing to separated detritus energy channels emerged, we found a clearly separated root energy channel under the legume L. corniculatus.     

Molecular analysis of the sex chromosomes of the platyfish Xiphophorus maculatus: Towards the identification of a new type of master sexual regulator in vertebrates

In contrast to mammals and birds, fish display an amazing diversity of genetic sex determination systems, with frequent changes during evolution possibly associated with the emergence of new sex chromosomes and sex‐determining genes. To better understand the molecular and evolutionary mechanisms driving this diversity, several fish models are studied in parallel. Besides the medaka (Oryzias latipes Temminck and Schlegel, 1846) for which the master sex‐determination gene has been identified, one of the most advanced models for studying sex determination is the Southern platyfish (Xiphophorus maculatus, Günther 1966). Xiphophorus maculatus belongs to the Poeciliids, a family of live‐bearing freshwater fish, including platyfish, swordtails and guppies that perfectly illustrates the diversity of genetic sex‐determination mechanisms observed in teleosts. For X. maculatus, bacterial artificial chromosome contigs covering the sex‐determination region of the X and Y sex chromosomes have been constructed. Initial molecular analysis demonstrated that the sex‐determination region is very unstable and frequently undergoes duplications, deletions, inversions and other rearrangements. Eleven gene candidates linked to the master sex‐determining gene have been identified, some of them corresponding to pseudogenes. All putative genes are present on both the X and the Y chromosomes, suggesting a poor degree of differentiation and a young evolutionary age for platyfish sex chromosomes. When compared with other fish and tetrapod genomes, syntenies were detected only with autosomes. This observation supports an independent origin of sex chromosomes, not only in different vertebrate lineages but also between different fish species.     

Intracapsular lensectomy and sulcus intraocular lens fixation in dogs with primary lens luxation or subluxation

Objective  To evaluate the postoperative results of lensectomy and sulcus intraocular lens fixation (SIOLF) via an ab interno approach in dogs with progressive lens subluxation or early luxation.
Study design  Retrospective study.
Animals studied  Twenty eyes from 19 dogs presented to the Animal Eye Clinic for lens luxation or subluxation between 1999 and 2006.
Methods  Medical records were reviewed to evaluate preoperative lens position, vision status, intraocular pressure (IOP), and whether surgery was performed on an emergent or elective nature. Lensectomy and SIOLF were performed and postoperative status including vision, glaucoma, and retinal detachment was assessed.
Results  Average age was 8.6 years (range 4–14 years) and 55% (11/20) were terriers. Patients were followed a mean of 29.2 months (range 1–92 months) after surgery. Retinal detachment or secondary glaucoma was observed in 1 of 20 (5%) and 5 of 20 (20%) eyes, respectively, with 1 of 20 (5%) exhibiting both. Mean preoperative IOP was 16 mmHg and preoperative lens position was equally divided between luxated and subluxated lenses. Surgery was performed more frequently as an elective procedure (18/20; 90%) due to normalized IOP vs. an emergency procedure (2/20; 10%). Vision was retained in 70% (14/20) of eyes with a mean time to vision loss of 41 months in the remaining eyes due to glaucoma, retinal detachment, or retinal degeneration.
Conclusions  Complications of glaucoma and retinal detachment after SIOLF in this study were less when compared with previously reported incidence rates in the literature for lensectomy alone which may reflect improved patient selection.     

A gene regulatory network subcircuit drives a dynamic pattern of gene expression

Early specification of endomesodermal territories in the sea urchin embryo depends on a moving torus of regulatory gene expression. We show how this dynamic patterning function is encoded in a gene regulatory network (GRN) subcircuit that includes the otx, wnt8, and blimp1 genes, the cis-regulatory control systems of which have all been experimentally defined. A cis-regulatory reconstruction experiment revealed that blimp1 autorepression accounts for progressive extinction of expression in the center of the torus, whereas its outward expansion follows reception of the Wnt8 ligand by adjacent cells. GRN circuitry thus controls not only static spatial assignment in development but also dynamic regulatory patterning.