Cryopreservation of non-encapsulated embryogenic tissue of sweet potato (Ipomoea batatas)

Embryogenic tissue of the sweet potato (Ipomoea batatas (L) LAM) genotype TIB 10 was established from in vitro axillary shoot tips on Murashige and Skoog (1962) medium supplemented with 5 M 2,4-dichlorophenoxyacetic acid. Embryogenic aggregates of fresh mass 9.0–12 mg were subjected to a rapid freezing protocol in liquid nitrogen following sucrose preculture and varying degrees of dehydration. Up to 50% of embryogenic explants survived rapid freezing after preculture on 0.4 or 0.7M sucrose only. Dehydration with silica gel to moisture contents in the range 18–41% improved the survival after cryopreservation of embryogenic tissue. Tissue dehydrated for intermediate periods exhibited poor survival. Following freezing, embryogenic tissue appeared to develop normally, retaining its competence to produce mature embryos and plantlets.Abbreviations BA 6-benzyladenine - 2,4-D 2,4-dichlorophenoxyacetic acid - MS Murashige and Skoog (1962) medium     

Assessment of xylazine hydrochloride epidural analgesia for open castration of rams

Epidural xylazine injected at the sacrococcygeal site 40 to 150 min prior to surgery (at a dose of 0.05 to 0.10 mg/kg) provided good analgesia during scrotal skin incision in all 20 experimental rams but in only 10 rams (50%) at incision and separation of tunica vaginalis, and 6 rams (30%) during ligation of the spermatic cord. There was a significant correlation between the decrease in heart rate and the dosage of epidural xylazine. Heart rate increased significantly during incision of the tunics and spermatic cord ligation but was not significantly correlated to the clinical assessment of analgesia. There was no significant correlation between the presence of surgical analgesia and the dosage of epidural xylazine: Pelvic limb ataxia was still evident in 12 rams (60%) at 8 h after epidural xylazine injection. Epidural xylazine provided good somatic analgesia during open castration of 20 rams but visceral analgesia was unpredictable. Factors in addition to the dosage of sacrococcygeal epidural xylazine affects the degree of surgical analgesia obtained for open castration of rams.     

Characterization of polysomes from Xenopus liver synthesizing vitellogenin and translation of vitellogenin and albumin messenger RNA's in vitro.

1. Conditions are described for the isolation of polysomes from the liver of Xenopus laevis. The method involves homogenization of liver in 0.2 M Tris-HCl pH 8.5, treatment with 2% Triton X-100 and subsequent sucrose density gradient fractionation of polysomes from a 10000 X g supernatant. 2. Vitellogenin synthesis was induced in male Xenopus liver by oestradiol treatment. Polysomes were isolated and vitellogenin-synthesizing polysomes characterized by their association with monospecific 125 I-labelled rabbit anti-vitellogenin antibody and by reaction with rabbit anti-vitellogenin immunoglobulins followed by indirect immunoprecipitation with goat anti-rabbit antibody. 3. Changes in liver polysome content following oestrogen treatment of male Xenopus are correlated with the appearance of vitellogenin synthesis using an organ culture assay. 4. RNA extracted from livers of oestradiol-treated male Xenopus and from purified polysomes is shown to code for the synthesis of vitellogenin-specific immunoprecipitable polypeptides in a rabbit reticulocyte cell-free protein-synthesizing system, a major component having a molecular weight of 210000. Xanopus liver RNA is also shown to code for the synthesis of an albumin-specific immunoprecipitable polypeptide of 74000 molecular-weight which coelectrophoresed with Xenopus albumin.     

Breeding latitude leads to different temporal but not spatial organization of the annual cycle in a long‐distance migrant

The temporal and spatial organization of the annual cycle according to local conditions is of crucial importance for individuals’ fitness. Moreover, which sites and when particular sites are used can have profound consequences especially for migratory animals, because the two factors shape interactions within and between populations, as well as between animal and the environment. Here, we compare spatial and temporal patterns of two latitudinally separated breeding populations of a trans‐Equatorial passerine migrant, the collared flycatcher Ficedula albicollis, throughout the annual cycle. We found that migration routes and non‐breeding residency areas of the two populations largely overlapped. Due to climatic constraints, however, the onset of breeding in the northern population was approximately two weeks later than that of the southern population. We demonstrate that this temporal offset between the populations carries‐over from breeding to the entire annual cycle. The northern population was consistently later in timing of all subsequent annual events – autumn migration, non‐breeding residence period, spring migration and the following breeding. Such year‐round spatiotemporal patterns suggest that annual schedules are endogenously controlled with breeding latitude as the decisive element pre‐determining the timing of annual events in our study populations.     

Swarm-founding in the polistine wasps: the importance of finding many microsatellite loci in studies of adaptation

We developed 52 microsatellite loci for the wasp, Polybioides tabidus, for the purpose of studying the evolution and inclusive fitness consequences of swarm-founding. The large number of loci is important for three reasons that may apply to many other systems. Heterozygosity was low in our target species, yet we found enough polymorphic loci for accurate kinship studies in this species. Many monomorphic loci were polymorphic in other polistine wasps, making comparative studies possible. Finally, enough loci amplified over a broad range of species to add a historical dimension. We sequenced six loci in other polistine wasps and used the flanking sequences to construct a phylogeny. Based on this phylogeny, we infer that swarm-founding has evolved independently three times in the polistine wasps.     

Treatment with apolipoprotein A-1 mimetic peptide reduces lupus-like manifestations in a murine lupus model of accelerated atherosclerosis

Introduction

The purpose of this study was to evaluate the effects of L-4F, an apolipoprotein A-1 mimetic peptide, alone or with pravastatin, in apoE^-/-Fas^-/-C57BL/6 mice that spontaneously develop immunoglobulin G (IgG) autoantibodies, glomerulonephritis, osteopenia, and atherosclerotic lesions on a normal chow diet.

Methods

Female mice, starting at eight to nine weeks of age, were treated for 27 weeks with 1) pravastatin, 2) L-4F, 3) L-4F plus pravastatin, or 4) vehicle control, followed by disease phenotype assessment.

Results

In preliminary studies, dysfunctional, proinflammatory high-density lipoproteins (piHDL) were decreased six hours after a single L-4F, but not scrambled L-4F, injection in eight- to nine-week old mice. After 35 weeks, L-4F-treated mice, in the absence/presence of pravastatin, had significantly smaller lymph nodes and glomerular tufts (P_{L, LP} < 0.05), lower serum levels of IgG antibodies to double stranded DNA (dsDNA) (P_L < 0.05) and oxidized phospholipids (oxPLs) (P_{L, LP} < 0.005), and elevated total and vertebral bone mineral density (P_{L, LP} < 0.01) compared to vehicle controls. Although all treatment groups presented larger aortic root lesions compared to vehicle controls, enlarged atheromas in combination treatment mice had significantly less infiltrated CD68⁺ macrophages (P_LP < 0.01), significantly increased mean α-actin stained area (P_LP < 0.05), and significantly lower levels of circulating markers for atherosclerosis progression, CCL19 (P_{L, LP} < 0.0005) and VCAM-1 (P_L < 0.0002).

Conclusions

L-4F treatment, alone or with pravastatin, significantly reduced IgG anti-dsDNA and IgG anti-oxPLs, proteinuria, glomerulonephritis, and osteopenia in a murine lupus model of accelerated atherosclerosis. Despite enlarged aortic lesions, increased smooth muscle content, decreased macrophage infiltration, and decreased pro-atherogenic chemokines in L-4F plus pravastatin treated mice suggest protective mechanisms not only on lupus-like disease, but also on potential plaque remodeling in a murine model of systemic lupus erythematosus (SLE) and accelerated atherosclerosis.     

Molecular architecture of the ribosome‐bound Hepatitis C Virus internal ribosomal entry site RNA

Internal ribosomal entry sites (IRESs) are structured cis‐acting RNAs that drive an alternative, cap‐independent translation initiation pathway. They are used by many viruses to hijack the translational machinery of the host cell. IRESs facilitate translation initiation by recruiting and actively manipulating the eukaryotic ribosome using only a subset of canonical initiation factor and IRES transacting factors. Here we present cryo‐EM reconstructions of the ribosome 80S‐ and 40S‐bound Hepatitis C Virus (HCV) IRES. The presence of four subpopulations for the 80S•HCV IRES complex reveals dynamic conformational modes of the complex. At a global resolution of 3.9 Å for the most stable complex, a derived atomic model reveals a complex fold of the IRES RNA and molecular details of its interaction with the ribosome. The comparison of obtained structures explains how a modular architecture facilitates mRNA loading and tRNA binding to the P‐site. This information provides the structural foundation for understanding the mechanism of HCV IRES RNA‐driven translation initiation.