Somatic embryogenesis and plant regeneration in Opuntia ficus-indica (L.) Mill. (Cactaceae)

We present here a method for the regeneration of the prickly-pear (Opuntia ficus-indica (L.) Mill.) through somatic embryogenesis (SE). Direct SE was induced by cultivating shoot apices devoid of leaf primordia on semisolid Murashige and Skoog (MS) basal medium supplemented with 4-amino 3,5,6-trichloropicolinic acid (picloram) at 4 mg l⁻¹. Somatic embryogenesis was influenced by the type, age, physiological and developmental stage of the explants, and also by light conditions, wounding, and the sucrose concentration in the induction medium. A histological analysis confirmed SE by revealing the presence of a closed vascular system in the developing embryos and the absence of a vascular connection between the somatic embryos and the explant.     

Haemolytic complement activity,C3 and Factor B consumption in serum from chickens divergently selected for antibody responses to sheep red blood cells

Antibody responses, serum complement haemolytic activity, and complement component C3 and Factor B consumption were studied in chickens divergently selected for high and low antibody responses to sheep red blood cells, and in a randombred control line. Significantly higher total and IgG antibody responses to SRBC were found after intramuscular immunisation in the high antibody responder (H) line versus the low antibody responder (L) line and the control (C) line. Also significantly higher antibody titres were found in the C line as compared to the L line. Ca-dependent (classical) and Ca-independent (alternative) complement haemolytic activity was significantly higher in the H line than in the L line. Also initial complement haemolytic activity and C3 levels prior to immunisation with SRBC were significantly higher in the H than in the L line. The L line, on the other hand, showed numerically higher Factor B levels. Immunisation with SRBC was followed by a different consumption of C3 in serum of the H line than the L line.The results indicated that divergent selection of chickens for specific antibody responses to SRBC affected complement levels and C3 consumption in these chickens. This suggests a genetic linkage between these two immune traits.     

Phylogeography of New World isolates of Anaplasma marginale based on major surface protein sequences

Gene and protein sequences of major surface proteins (MSP) 1a and 4 of Anaplasma marginale (Rickettsiales: Anaplasmataceae) were used to infer phylogenetic relationships between New World isolates from Argentina, Brazil, Mexico and the United States. Seventeen isolates of A. marginale plus two outgroup taxa (A. centrale and A. ovis) were used for maximum-parsimony analysis of MSP4, while 20 isolates were used for phylogenetic analysis of MSP1a. msp4 analysis provided strong bootstrap support for a Latin American clade and, within this clade, support was detected for Mexican and South American clades. Isolates of A. marginale from the United States also grouped into two clades from the southern (isolates from Florida, Mississippi, and Virginia) and west-central (isolates from California, Idaho, Illinois, Oklahoma, and Texas) states. Although little phylogeographic resolution was detected within these higher clades, msp4 sequences appear to be a good genetic marker for inferring phylogeographic patterns of A. marginale isolates. In contrast to the phylogeographic resolution provided by msp4, MSP1a DNA and protein sequence were quite variable and did not provide phylogeographic resolution. Most variation in MSP1a sequences appeared unique to a given isolate and similar DNA sequence variation in msp1alpha was detected within isolates from Idaho and Florida and from Idaho and Argentina. The results of these studies demonstrated that msp4 provided phylogenetic information on the evolution of A. marginale isolates. In contrast MSP1a sequences appeared to be rapidly evolving and these sequences may provide phylogeographic information only when numerous isolate MSP1a sequences are analyzed from a geographic area.     

Investigation of putative CDT gene in Escherichia coli isolates from pigs with diarrhea

In this study, 98 Escherichia coli isolates from 42 diarrheic neonatal piglets were screened for the presence of cytolethal distending toxin coding gene by polymerase chain reaction (PCR). PCR yielded a single product which was specifically generated for E. coli cdt(+) control strain and not for other control strains. Twenty two (22.4%) of the isolates tested were cdtB positive, and 50% of the cdtB(+) isolates were also estII positive. The most prevalent pathotype was O32 cdtB(+) estII(+), which accounted for 59% of the cdtB positive strains. These results indicate an association between the presence of the cdtB gene and diarrhea, and support the need for further studies to determine the role of this toxin in diarrhea.     

Liposome-encapsulated doxorubicin (Doxil) and doxorubicin in the treatment of vaccine-associated sarcoma in cats

The purpose of this randomized, multicenter study was to evaluate the toxicity and efficacy of liposome-encapsulated doxorubicin (LED) and doxorubicin (DOX) in the treatment of feline vaccine-associated sarcoma (VAS). Cats were divided according to their disease status into a microscopic arm (no evidence of gross disease) and a macroscopic arm (evidence of gross disease). Each arm was randomized to receive either LED (1-1.5 mg/kg i.v. q3 weeks) or DOX (1 mg/kg i.v. q3 weeks). Thirty-three cats were entered in the macroscopic arm of the study with an overall response rate of 39% (5 complete response and 8 partial response) and a median time to progression of 84 days. Response rates were not different between LED and DOX. Seventy-five cats were entered into the microscopic arm. When compared to a similar historical control population treated with surgery alone, the cats receiving chemotherapy had a prolonged median disease-free interval (388 days versus 93 days). No difference in efficacy was detected between LED and DOX. LED at 1.5 mg/kg induced delayed nephrotoxicosis in 23%, necessitating a decrease in the recommended dosage to 1 mg/kg, and cutaneous toxicosis in 21.7% of treated cats. This study showed that both DOX and LED are efficacious in the treatment of VAS and should be considered in the treatment of this tumor.     

Morphological aspects of the capybara stomach (Hydrochaeris hydrochaeris): gross and microscopic structure

The digestive system of the capybara has been investigated because of its coprofagia habits, important for their absorptive activity. These species present differences in terms of gastrointestinal morphological characters when compared with other rodents. Macroscopiclly, the stomach of the capybara is constituted of the following parts: cardiac, pyloric, body, fundic and gastric diverticulum. It presents two curvatures, one big and another small. Externally, the presence of gastric bands (tenias) is observed. With regards to the volumetric view, the gastric capacity varies from 850 to 2010 ml, with an average of 1498.57 ml. So, the stomach of this animal can be classified as a simple stomach, in the format of a curved sack and similar to an inverted letter 'J'. The gastric mucous membrane presents a surface filled by numerous tortuous gastric folds and longitudinally distributed along all its extension. The mucous tunic also possesses recesses located among the successive gastric folds, which were denoted as gastric parts with numerous openings described as gastric pits. In the cardiac part, a glandular epithelium with cardiac glands is noticed containing a lot of parietal and mucous neck cells. The fundic part, body and gastric diverticulum contain proper gastric glands with main, parietal and mucous neck cells. Finally, the pyloric part has pyloric glands with two cellular types, mucous neck and parietal cells.     

Summary of workshop findings for antibodies reacting with porcine T-cells and activation antigens: results from the Second International Swine CD Workshop

After initial evaluation of the 176 new and 19 control monoclonal antibodies (mAb) submitted to the Second International Swine CD Workshop, 57 were assigned to the T-cell/activation marker subgroup. These 57 mAb were further analyzed using flow cytometry on whole blood lymphocytes, splenocytes, Peyer's patch lymphocytes, in vitro cell lines, broncho-alveolar lavage cells, Con A and PHA blasts, fetal cell populations, and by 2-color flow cytometry against mAb to porcine CD2, CD4, and CD8. Finally, the molecular weights of the target antigens were characterized when possible. As a result of these analyses, 23 mAb were distributed into 7 CD clusters. Newly confirmed mAb assignments included: two CD2; one CD4; two CD5; one wCD6; and one wCD25. Three new mAb were found that reacted with wCD8, one of which defined a new epitope, wCD8c. For the first time, mAb against porcine CD3 were identified, including 6 mAb that reacted with three different epitopes. Several new mAb reacted with antigens whose expression varied depending on the activation state of the test cell. These will require further characterization in order to assign a CD number.