Developmental changes in ketogenic enzyme gene expression during sheep rumen development

Ketogenesis is the conversion of acetyl-CoA to the ketone bodies acetoacetate and beta-hydroxybutyrate (BHBA). In hepatic ketogenesis, which occurs during fasting in both nonruminant and ruminant animals, the source of acetyl-CoA is the mitochondrial oxidation of predominantly long-chain fatty acids. In the mature, fed ruminant animal, the ruminal epithelium is also capable of producing ketone bodies. In this case, the source of acetyl-CoA is the mitochondrial oxidation of butyrate produced by the microbial fermentation of feed. The purposes of this study were to determine ontogenic and dietary effects on ketogenic enzyme gene expression in developing lamb ruminal epithelium. Twenty-seven conventionally reared lambs and twenty-seven milk-fed lambs were slaughtered between 1 and 84 d of age. Six additional milk-fed lambs were weaned (the fed group) or maintained on milk replacer with a volatile fatty acid gavage (the VFA group) until 84 d of age. At slaughter, total RNA was extracted from samples of ruminal epithelium. The expression of the genes encoding acetoacetyl-CoA thiolase, the first enzyme in the ketogenic pathway, and 3-hydroxy-3-methylglutaryl-CoA synthase, the rate-limiting enzyme in the ketogenic pathway in nonruminant liver, were examined. Acetoacetyl-CoA thiolase and 3-hydroxy-3-methylglutaryl-CoA synthase mRNA concentrations increased with age independent of diet. 3-Hydroxy-3-methylglutaryl-CoA synthase mRNA levels in ruminal epithelium obtained from milk-fed lambs were low before 42 d of age, but a marked increase occurred by 42 d of age. At 84 d of age, there were no differences in acetoacetyl-CoA thiolase and 3-hydroxy-3-methylglutaryl-CoA synthase expression due to diet. The pattern of the expression of these genes, in particular, 3-hydroxy-3-methylglutaryl-CoA synthase, parallels the rate of production of BHBA by rumen epithelial cells isolated from the same lambs, which increased to conventionally reared adult levels at 42 d of age and did not differ with diet. In conclusion, development of the ketogenic capacity of the ruminal epithelium occurs as the animal ages, regardless of dietary treatment. Thus, the expression of the genes encoding the ketogenic enzymes are not affected by the presence of VFA in the ruminal lumen.     

Production and Processing Trait Comparisons of Channel Catfish,Blue Catfish,and Their Hybrids Grown in Earthen Ponds

Fingerling HS‐5 channel catfish, Ictalurus punctatus, NWAC 103 channel catfish, D&B blue catfish, Ictalurus furcatus, HS‐5 female channel × D&B male blue catfish F₁ hybrids, and NWAC 103 female channel × D&B male blue catfish F₁ hybrids were stocked into twenty‐five 0.04‐ha earthen ponds at 12,500 fish/ha and grown for 277 d. Fish were fed daily at rates from 1.0 to 3.0% biomass based on feeding activity and temperature and adjusted weekly assuming a feed conversion ratio (FCR) of 1.8 and 100% survival. At harvest, 40 fish from each pond were sampled, and all other counted and weighed. Mean survival, growth rate indexes (a), FCR, and skin‐on fillet percentages were not significantly different. Mean harvest weights and net production were higher for HS‐5 channel and its hybrid than for the NWAC 103 channel, NWAC 103 hybrid, and D&B blue catfish, partially because of their larger mean stocking weights. D&B blue catfish was more uniform in size than NWAC 103 channel and NWAC 103 hybrid. D&B blue catfish was the easiest to seine. HS‐5 hybrids and NWAC 103 hybrids had lower mean head percentage and a better processing yield than their parent channel catfish.     

A Survey of Forestland Conservation Easements in the United States: Implications for Forestland Owners and Managers

Internationally, conservation easements are increasingly popular land management tools for private landowners, government agencies and non-governmental organizations seeking to preserve forests and other natural settings. This paper reports a study of the design and use of conservation easements by organizations and public agencies in the USA. More than 355 conservation organizations and 16 state agencies holding at least 3,598 forestland easements were identified. Demonstrated shortfalls in baseline forest inventories, record keeping, and professionally-developed management plans were evident on working forest easements. Failure to address these shortcomings runs the risk of jeopardizing the legitimacy of the easement approach even where favorable legal and tax conditions exist. Management restrictions varied broadly, with a minority of respondents prohibiting such techniques as clearcutting and salvage logging. Concerns for the use of chemicals, best management practices, and streamside management zones were commonly reflected in easement language, whereas logging road design and the cultivation of old-growth conditions remain largely undeveloped. Implications from the US experience, where easements are relatively well-developed, highlights the need for professional forestry advice—particularly for non-industrial or small-scale forest owners—in both easement development and implementation, the need for careful planning, and the need to carefully consider the respective goals of the forest landowners in crafting the easement documents. In the cases of developing nations, consideration of the differing needs of landowners may require increased flexibility in management documents.     

Comparison of meniscal fibrochondrocyte and synoviocyte bioscaffolds toward meniscal tissue engineering in the dog

Tissue engineering is a promising field of study toward curing the meniscal deficient stifle; however the ideal cell type for this task is not known. We describe here the extraction of synoviocytes and meniscal fibrochondrocytes from arthroscopic debris from six dogs, which were cultured as tensioned bioscaffolds to synthesize meniscal-like fibrocartilage sheets. Despite the diseased status of the original tissues, synoviocytes and meniscal fibrochondrocytes had high viability at the time of removal from the joint. Glycosaminoglycan and collagen content of bioscaffolds did not differ. Meniscal fibrochondrocyte bioscaffolds contained more type II collagen, but collagen deposition was disorganized, with only 30–40% of cells viable. The collagen of synoviocyte bioscaffolds was organized into sheets and bands and 80–90% of cells were viable. Autologous, diseased meniscal fibrochondrocytes and synoviocytes are plausible cell sources for future meniscal tissue engineering research, however cell viability of meniscal fibrochondrocytes in the tensioned bioscaffolds was low.     

Culture of canine synoviocytes on porcine intestinal submucosa scaffolds as a strategy for meniscal tissue engineering for treatment of meniscal injury in dogs

Meniscal injury is a common cause of canine lameness. Tissue engineered bioscaffolds may be a treatment option for dogs suffering from meniscal damage. The aim of this study was to compare in vitro meniscal-like matrix formation and biomechanical properties of porcine intestinal submucosa sheets (SIS), used in canine meniscal regenerative medicine, to synoviocyte-seeded SIS bioscaffold (SSB), cultured with fetal bovine serum (SSBfbs) or chondrogenic growth factors (SSBgf). Synoviocytes from nine dogs were seeded on SIS and cultured for 30 days with 17.7% fetal bovine serum or recombinant chondrogenic growth factors (IGF-1, TGFβ1 and bFGF). The effect on fibrochondrogenesis was determined by comparing mRNA expression of collagen types Iα and IIα, aggrecan, and Sry-type homeobox protein-9 (SOX9) as well as protein expression of collagens I and II, glycosaminoglycan (GAG), and hydroxyproline.The effect of synoviocyte seeding and culture conditions on biochemical properties was determined by measuring peak load, tensile stiffness, resilience, and toughness of bioscaffolds. Pre-culture SIS contained 13.6% collagen and 2.9% double-stranded DNA. Chondrogenic growth factor treatment significantly increased SOX9, collagens I and IIα, aggrecan gene expression (P < 0.05), and histological deposition of fibrocartilage extracellular matrix (GAG and collagen II). Culture with synoviocytes increased SIS tensile peak load at failure, resilience, and toughness of bioscaffolds (P < 0.05). In conclusion, culturing SIS with synoviocytes prior to implantation might provide biomechanical benefits, and chondrogenic growth factor treatment of cultured synoviocytes improves in vitro axial meniscal matrix formation.     

A new order of tertiary zalambdodont marsupials

Yalkaparidon coheni and Yalkaparidon jonesi are described here as the first-known members of the marsupial family Yalkaparidontidae and order Yalkaparidontia. Before discovery of these zalambdodont marsupials in unnamed Tertiary sediments from northwestern Queensland, only five orders of australidelphian marsupials were known. Dental and basicranial morphology suggest that notoryctids and yalkaparidontids, which both have highly specialized zalambdodont molars, are dentally convergent. Yalkaparidontids lived in lowland rainforests of northern Australia and appear to have vanished, with the rainforests, sometime in the middle to late Tertiary. Discovery of yalkaparidontids demonstrates a significantly greater breadth of diversity for Australian marsupials.     

Gas adsorption sites in a large-pore metal-organic framework

The primary adsorption sites for Ar and N2 within metal-organic framework-5, a cubic structure composed of Zn4O(CO2)6 units and phenylene links defining large pores 12 and 15 angstroms in diameter, have been identified by single-crystal x-ray diffraction. Refinement of data collected between 293 and 30 kelvin revealed a total of eight symmetry-independent adsorption sites. Five of these are sites on the zinc oxide unit and the organic link; the remaining three sites form a second layer in the pores. The structural integrity and high symmetry of the framework are retained throughout, with negligible changes resulting from gas adsorption.     

Fear erasure in mice requires synergy between antidepressant drugs and extinction training

Antidepressant drugs and psychotherapy combined are more effective in treating mood disorders than either treatment alone, but the neurobiological basis of this interaction is unknown. To investigate how antidepressants influence the response of mood-related systems to behavioral experience, we used a fear-conditioning and extinction paradigm in mice. Combining extinction training with chronic fluoxetine, but neither treatment alone, induced an enduring loss of conditioned fear memory in adult animals. Fluoxetine treatment increased synaptic plasticity, converted the fear memory circuitry to a more immature state, and acted through local brain-derived neurotrophic factor. Fluoxetine-induced plasticity may allow fear erasure by extinction-guided remodeling of the memory circuitry. Thus, the pharmacological effects of antidepressants need to be combined with psychological rehabilitation to reorganize networks rendered more plastic by the drug treatment.     

Effects of Bulk Density on Sediment Erosion Rates

By means of a recently developed flume, sediment erosion rates as a function of shear stress and with depth in the sediments have previously been determined for relatively undisturbed sediments from several rivers and lakes. These experiments demonstrated that erosion rates depended on at least the following parameters: bulk density (or water content) of the sediments, particle size distribution as well as mean particle size, mineralogy, organic content, and amounts and sizes of gas bubbles. In order to isolate and quantify the effects of one of these parameters, the bulk density, additional experiments have been done with reconstructed sediments and are reported here. These experiments first determined the bulk density as a function of depth in the sediments for three different types of sediments, for three different sediment core lengths, and for compaction times varying from 1 to 60 days. For each of these sediment cores and compaction times, the erosion rate as a function of shear stress and with depth was then measured and related to the local bulk density of the sediment. The results demonstrate that, for a particular sediment and shear stress, the erosion rate is a unique function of the bulk density and can be expressed as a product of powers of the shear stress and bulk density.     

Review of clinical aspects,epidemiology and diagnosis of haemotropic Mycoplasma ovis in small ruminants: current status and future perspectives in tropics focusing on Malaysia

Mycoplasma ovis (formerly Eperythrozoon ovis) is an epierythrocytic parasitic bacterium of small ruminants known as haemotropic mycoplasma, which is transmitted mechanically by biting flies and contaminated instruments. Acute mycoplasmosis causes severe haemolytic anaemia and mortality in young animals. At the same time, chronic disease may produce mild anaemia and varying degrees of morbidity depending on several factors, including age, reproductive status, the plane of nutrition, immunological status and the presence of concurrent infection. Haemotropic Mycoplasma ovis is currently recognised as an emerging zoonotic pathogen which is widely distributed in the sheep and goat producing areas of tropics and subtropics, where the disease is nearly endemic. Human infection has been reported in pregnant women, immunocompromised patients and people exposed to animals and arthropods. The current diagnosis of haemoplasma relies on microscopic evaluation of Giemsa-stained blood smear and PCR. Although there are few published reports on the incidence of haemotropic Mycoplasma ovis infection of small ruminants in Malaysia, information on its prevalence, risk factors, severity and economic impacts is grossly inadequate. Therefore, a large-scale survey of small ruminant flocks is necessary to elucidate the current seroprevalence status and molecular characteristics of haemotropic M. ovis infection in Malaysia using ELISA and PCR sequencing technologies. In the future, surveillance programs, including vector forecast, quarantine, monitoring by periodic surveys and public enlightenment, will limit the internal and transboundary spread of M. ovis, enhance control efforts and mitigate production losses in Malaysia.