Post‐release dispersal and spawning movements of a translocated lake sturgeon (Acipenser fulvescens,Rafinesque 1817) population in the Mattagami River,Ontario

Species translocations are increasingly being used as a management tool to mitigate population losses due to such factors as habitat degradation and fragmentation, but post‐introduction follow‐up is relatively sparse. Post‐translocation telemetry can assess success by identifying activity, emigrations, survival, habitat usage, and reproductive events, aiding in the continued management of translocated populations and informing future efforts. This study assessed movement of translocated adult lake sturgeon (Acipenser fulvescens) immediately post‐release and a decade later, and tested for associations between environmental variables and spawning movements. Prior to their translocation in 2002, 13 of 51 adult lake sturgeon were surgically implanted with radio telemetry tags and tracked for 1 year. In 2011 and 2013, eight additional adults were captured within the reintroduction site and implanted with radio‐tags. Six of the 13 sturgeon tagged in 2002 dispersed downstream over a dam during the early post‐release period. In spring 2014, tagged adults were tracked to the spillway at the release area's inflow, and spawning was confirmed by larval captures. Movement data for tagged adults differed between the two tracking periods, showing marked differences in behaviour over time. Water velocity was correlated with upstream and downstream spawning movements, with water temperature also correlated with downstream movement. Research regarding post‐translocation movement and dispersal provides insight on behavioural responses following translocation, and may improve outcomes by informing future efforts.     

Identification of methylation markers for the prediction of nodal metastasis in oral and oropharyngeal squamous cell carcinoma

Hypermethylation is an important mechanism for the dynamic regulation of gene expression, necessary for metastasizing tumour cells. Our aim is to identify methylation tumour markers that have a predictive value for the presence of regional lymph node metastases in patients with oral and oropharyngeal squamous cell carcinoma (OOSCC). Significantly differentially expressed genes were retrieved from four reported microarray expression profiles comparing pN0 and pN+ head-neck tumours, and one expression array identifying functionally hypermethylated genes. Additional metastasis-associated genes were included from the literature. Thus genes were selected that influence the development of nodal metastases and might be regulated by methylation. Methylation-specific PCR (MSP) primers were designed and tested on 8 head-neck squamous cell carcinoma cell lines and technically validated on 10 formalin-fixed paraffin-embedded (FFPE) OOSCC cases. Predictive value was assessed in a clinical series of 70 FFPE OOSCC with pathologically determined nodal status. Five out of 28 methylation markers (OCLN, CDKN2A, MGMT, MLH1 and DAPK1) were frequently differentially methylated in OOSCC. Of these, MGMT methylation was associated with pN0 status (P = 0.02) and with lower immunoexpression (P = 0.02). DAPK1 methylation was associated with pN+ status (P = 0.008) but did not associate with protein expression. In conclusion, out of 28 candidate genes, two (7%) showed a predictive value for the pN status. Both genes, DAPK1 and MGMT, have predictive value for nodal metastasis in a clinical group of OOSCC. Therefore DNA methylation markers are capable of contributing to diagnosis and treatment selection in OOSCC. To efficiently identify additional new methylation markers, genome-wide methods are needed.     

The effect of colchicine on synapsis and chiasma formation in microsporocytes of Lilium

Microsporocytes of Lilium that are exposed to colchicine as late as early zygotene show reduced chiasma frequencies and the presence of univalents at Division I. These effects are preceded at pachytene by the appearance of pairing gaps (light microscopy) and by a relatively high ratio of uncomplexed lateral elements/synaptonemal complexes (EM). Chiasma formation thus appears to be reduced by failures in synapsis. Unlike the behavior of wheat, colchicine can disrupt chiasma formation in Lilium after cells have entered meiosis.     

Lytic Cycle of Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular pathogen within the phylum Apicomplexa. This protozoan parasite is one of the most widespread, with a broad host range including many birds and mammals and a geographic range that is nearly worldwide. While infection of healthy adults is usually relatively mild, serious disease can result in utero or when the host is immunocompromised. This sophisticated eukaryote has many specialized features that make it well suited to its intracellular lifestyle. In this review, we describe the current knowledge of how the asexual tachyzoite stage of Toxoplasma attaches to, invades, replicates in, and exits the host cell. Since this process is closely analogous to the way in which viruses reproduce, we refer to it as the Toxoplasma “lytic cycle.”     

The effect of fibrin structure on fibrinolysis.

Fibrin structure contributes to the regulation of the fibrinolytic rate. As the fibrin fiber size is decreased, the fibrinolytic rate also decreases. Fibrin structure was altered by either changing the ratio of thrombin to fibrinogen, i.e. altering the assembly rate or by adding a fibrin assembly inhibitor, iopamidol. Changes in the fibrinolytic rate were followed by measuring the time dependence of the decrease in the fiber mass/length ratio during fibrinolysis. A measure of the overall fibrinolytic rate was determined from the decrease in the mass/length ratio versus time. An 8-fold reduction in the fibrinolytic rate was seen on decreasing the mass/length ratio from 2.7 x 10(12) daltons/cm to 0.5 x 10(12) daltons/cm. It is shown that thin fibrin fibers have a decreased rate of conversion of plasminogen to plasmin by tissue plasminogen activator and that thin fibrin fibers are lysed more slowly than thick fibrin fibers.     

The Use of Enrichment Serology for Salmonella Detection in Human Foods and Animal Feeds

S ummary . Samples (2208) of food raw materials and products were examined for the presence of salmonellae by use of conventional salmonella detection procedures and the enrichment serology (ES) techniques described by Sperber & Deibel (1969); 348 samples were positive for salmonellae by the conventional procedures. Using the ES technique with a 24 h elective enrichment step, 93–98% of samples positive by the conventional procedures were also positive by the ES technique. Selective enrichment of food samples using tetrathionate broth containing novobiocin, incubated at 41°, led to the best recovery of salmonellae by both the conventional and ES techniques.     

MOTION PICTURE AND ELECTRON MICROSCOPE STUDIES ON THE EMBRYONIC AVIAN OSTEOCLAST

Time-lapse motion picture studies were carried out on isolated fowl embryo osteoclasts in vitro, the cells have an extremely active ruffled border, and show vigorous pinocytotic activity. Electron microscope studies on osmium-fixed cells showed that the pinocytotic vacuoles contained bone salt crystals (as well as material which could not be identified on morphological grounds), and that the folds of the ruffled border enclosed crystals and collagen fibrils. Changes were seen in the matrix beneath the ruffled border. Initially, the collagen fibres became separated from each other and at the same time bone salt crystals became detached from them. Later, as crystals and ground substance disappeared, the outline and cross-striation of the collagen became distinct. The implications of these findings are discussed with respect to the mechanism of bone erosion.     

Lack of introns in the ribosomal protein gene S14 of trypanosomes.

Introns are almost always present in ribosomal protein genes, even in organisms in which introns are rare. Although trans spliced, the trypanosome ribosomal protein gene S14 apparently does not have cis introns, which supports the notion that such introns are absent in this organism.