Modelling intraspecific resting egg shape variation in a freshwater fairy shrimp Tanymastix stagnalis (L., 1758) (Crustacea, Branchiopoda)

The shape of the resting eggs of a large branchiopod crustacean, the Anostraca Tanymastix stagnalis , is represented very accurately by analytical expressions. The occurrence of atypical shape of some T. stagnalis eggs may be viewed as a simple change of the analytical expression describing the usual egg shape. Their unusual shape may be explained by a higher embryo volume within an envelope of a given size. Biological implications are briefly discussed and hypothesized in an evolutionary point of view.  © 2007 The Linnean Society of London, Biological Journal of the Linnean Society , 2007, 90 , 55–60.     

Exercise inhibits progressive growth of the Morris hepatoma 7777 in male and female rats

Male and female rats were either trained to swim for a 6-week period or they remained sedentary. Rats were implanted with Morris hepatoma 7777 after 3 weeks of swimming and were sacrificed after a further 3 weeks. Exercised rats of both sexes showed a significant reduction in tumour weight at sacrifice, compared with sedentary controls (p less than 0.01). Similarly, when rats were first implanted with tumours and then placed on an exercise program of 3 weeks duration, tumour growth was also reduced (p less than 0.05). These results suggest that the tumour may be sensitive to exercise at more than one point in its development. Tumour growth was inhibited to a similar extent whether the total swimming time was 10, 20, or 30 h over the 3-week period. Although sedentary, tumour-bearing rats were anorexic; both male and female rats showed significant improvement of appetite during the period of tumour growth, in response to exercise. Tumour implantation was associated with significant losses of whole body and muscle protein. The progression of this wasting was not significantly altered by exercise.     

Prostaglandin production in myotube cultures. Influence on protein turnover.

The production of prostaglandins (PG) E2 and F2 alpha and their possible role in regulation of protein turnover in cultured skeletal-muscle cells were examined. Primary chick myoblasts and myotubes, and L8 myotubes, produced PGE2 and PGF2 alpha from endogenous arachidonic acid. PG production by all three cell types was increased manyfold by the addition of exogenous arachidonic acid. Arachidonate-stimulated PG production was inhibited by the addition of indomethacin (0.1 mM). When L8 and chick myotubes were treated with PGE2, PGF2 alpha, arachidonic acid (0.01 mM) or indomethacin (0.1 mM), no significant alterations in rates of protein synthesis or degradation were observed. Rates of protein synthesis and degradation in these cells were responsive to the addition of 10% fetal-bovine serum under identical experimental conditions. Thus, in contrast with incubated adult skeletal muscle, it appears that the production of prostaglandin metabolites from arachidonic acid is unrelated to regulation of protein turnover in cultured muscle cells.     

Adult movements between populations in the specialist butterfly Proclossiana eunomia (Lepidoptera, Nymphalidae)

Abstract.

• 1 The structure of local populations of a monophagous butterfly, the bog fritillary Proclossiana eunomia, was studied in a complex of suitable habitat patches separated by spruce plantations or fertilized pasture.
• 2 An unexpected high level of adult movements between habitat patches was detected by a mark—release—recapture technique. Local populations were connected by adult movements across unsuitable habitats, leading to a meta-population structure.
• 3 This evidence of the metapopulation structure of a specialist butterfly challenges the supposed relationship between habitat specialization and closed, isolated populations.
• 4 Males and females of P.eunomia exhibited different spatial behaviours; females were more likely to emigrate and dispersed further than males. These differences in spatial behaviour are related to the mating system.

     

Isolation and characterization of tetranucleotide microsatellite markers in a mouth‐brooding haplochromine cichlid fish (Pseudocrenilabrus multicolor victoriae) from Uganda

Eight tetranucleotide microsatellite loci were isolated from the haplochromine cichlid fish, Pseudocrenilabrus multicolor victoriae, an important model species for studies in respiratory ecology, conservation, and evolution. We surveyed variation at these loci in 23 individuals from western Uganda, finding four to 19 alleles per locus and an average expected heterozygosity of 0.8575. These microsatellite loci will be used to examine gene flow and population structure in Ugandan P. m. victoriae.     

USP19 is a ubiquitin-specific protease regulated in rat skeletal muscle during catabolic states

Ubiquitin-dependent proteolysis is activated in skeletal muscle atrophying in response to various catabolic stimuli. Previous studies have demonstrated activation of ubiquitin conjugation. Because ubiquitination can also be regulated by deubiquitinating enzymes, we used degenerate oligonucleotides derived from conserved sequences in the ubiquitin-specific protease (UBP) family of deubiquitinating enzymes in RT-PCR with skeletal muscle RNA to amplify putative deubiquitinating enzymes. We identified USP19, a 150-kDa deubiquitinating enzyme that is widely expressed in various tissues including skeletal muscle. Expression of USP19 mRNA increased by approximately 30-200% in rat skeletal muscle atrophying in response to fasting, streptozotocin-induced diabetes, dexamethasone treatment, and cancer. Increased mRNA levels during fasting returned to normal with refeeding, but 1 day later than the normalization of rates of proteolysis and coincided instead with recovery of muscle mass. Indeed, in all catabolic treatments, USP19 mRNA was inversely correlated with muscle mass and provided an index of muscle mass that may be useful in many pathological conditions, using small human muscle biopsies. The increased expression of this deubiquitinating enzyme under conditions of increased proteolysis suggests that it may play a role in regeneration of free ubiquitin either coincident with or after proteasome-mediated degradation of substrates. USP19 may also be involved in posttranslational processing of polyubiquitin produced de novo in response to induction of the polyubiquitin genes seen under these conditions. Deubiquitinating enzymes thus appear involved in muscle wasting and implicate a widening web of regulation of genes in the ubiquitin system in this process.     

Skeletal Muscle Radio-Density Is an Independent Predictor of Response and Outcomes in Follicular Lymphoma Treated with Chemoimmunotherapy

Skeletal muscle radio-density (SMD) measures muscle radiation attenuation (in Hounsfield Units, HU) on computed tomography (CT) scans. Low SMD is prognostic of poor survival in melanoma, however its significance is unknown for hematologic malignancies. We performed a single institution, retrospective review of all follicular lymphoma (FL) patients who received chemoimmunotherapy from 2004–2009. Patient demographics, FL International Prognostic Index 1 (FLIPI-1), progression free (PFS) and overall survival (OS) were collected as primary endpoints. Objective response rates (ORR) were secondary. SMD was calculated using pre-treatment CT scans. In 145 patients reviewed, median values were age 59, FLIPI-1 of 2, stage III, and 8 chemoimmunotherapy cycles received. Median PFS for those with low SMD (<36.6 and <33.1 HU for patients with BMI ≤ 25 and > 25 kg/m², respectively) compared to those with high SMD was profoundly worse, 69.6 vs. 106.7 months (hazard ratio [HR] 1.85; p = 0.01), respectively. Median OS was not reached in patients with high SMD vs. 92.7 months in low SMD patients (HR 4.02; p = 0.0002). Multivariate analysis supported lower SMD’s OS detriment (HR = 3.40; p = 0.002) independent of FLIPI-1 (HR 1.46–2.76, p = 0.05) or gender. Low SMD predicted lower ORR, 83 vs. 96% (p = 0.01). SMD predicts survival independent of FLIPI-1 and potentially chemoimmunotherapy response. SMD is an inexpensive and powerful tool that can complement FLIPI-1.