Somatic embryogenesis from leaf derived callus of Tylophora indica (Burm. f.) Merrill

Mature leaf explant derived callus of Tylophora indica (Burm. f.) Merrill yielded somatic embryos on MS medium supplied with BA(1-2 mg/L) or kinetin(1-5 mg/L) or kinetin/BA (1-2 mg/L) used along with IAA(0.1-1 mg/L). Maximum somatic embryos (30) could be recovered from 100 mg of embryogenic callus within 60 days at an optimum concentration of 2 mg/L of BA which was also best suited for providing the maximum conversion rate (90%) of embryoids to plantlets. Kinetin (1-5 mg/L), used as the sole growth hormone, induced the development of embryoids showing either shoot or root primordia in 30% of the cultures. However, embryoids with shoot primordia developed roots upon transfer to medium containing IAA(0.1 mg/L) and kinetin(2 mg/L). Embryoids from all cultures germinated in the initiation medium and were transplanted to sterile vermiculite for hardening. After two weeks of hardening, the plantlets were transferred to the green house where they grew and established well showing a high rate of survival (90%).     

Detection of Cyclospora cayetanensis in Wastewater

Cyclospora cayetanensis causes diarrheal disease worldwide without a confirmed mode of transmission. Wastewater was examined for the presence of this organism. Oocysts were detected microscopically, and their identity was confirmed by molecular techniques. These findings verify that current techniques can isolate Cyclospora oocysts and suggest that fecally contaminated water may act as a vehicle of transmission.     

MFR, a Putative Receptor Mediating the Fusion of Macrophages

We had previously identified a macrophage surface protein whose expression is highly induced, transient, and specific, as it is restricted to actively fusing macrophages in vitro and in vivo. This protein is recognized by monoclonal antibodies that block macrophage fusion. We have now purified this protein and cloned its corresponding cDNA. This protein belongs to the superfamily of immunoglobulins and is similar to immune antigen receptors such as the T-cell receptor, B-cell receptor, and viral receptors such as CD4. We have therefore named this protein macrophage fusion receptor (MFR). We show that the extracellular domain of MFR prevents fusion of macrophages in vitro and therefore propose that MFR belongs to the fusion machinery of macrophages. MFR is identical to SHPS-1 and BIT and is a homologue of P84, SIRPα, and MyD-1, all of which have been recently cloned and implicated in cell signaling and cell-cell interaction events.     

Myocyte enlargement, differentiation, and proliferation kinetics in the fetal sheep heart.

The generation of new myocytes is an essential process of in utero heart growth. Most, or all, cardiac myocytes lose their capacity for proliferation during the perinatal period through the process of terminal differentiation. An increasing number of studies focus on how experimental interventions affect cardiac myocyte growth in the fetal sheep. Nevertheless, fundamental questions about normal growth of the fetal heart remain unanswered. In this study, we determined that during the last third of gestation the hearts of fetal sheep grew primarily by four processes. 1) Myocyte proliferation contributed substantially to daily cardiac mass gain, and the number of cardiac myocytes continued to increase to term. 2) The (hitherto unrecognized) contribution to cardiac growth by the increase in myocyte size associated with the transition from mononucleation to binucleation (terminal differentiation) became considerable from approximately 115 days of gestational age (dGA) until term (145dGA). Because binucleation became the more frequent outcome of myocyte cell cycle activity after approximately 115dGA, the number of binucleated myocytes increased at the expense of the number of mononucleated myocytes. Both the interval between nuclear divisions and the duration of cell cycle activity in myocytes decreased substantially during this same period. Finally, cardiac growth was in part due to enlargement of 3) mononucleated and 4) binucleated myocytes, which grew in cross-sectional diameter but not length during the last third of gestation. These data on normal cardiac growth may enable a more detailed understanding of the consequences of experimental and pathological interventions in prenatal life.     

Interaction of heparin with cationic molecular probes: Probe charge is a major determinant of binding stoichiometry and affinity

Fluorescent perylenediimide probes modified with 2, 4, 6, or 8 ammonium groups were synthesized and their binding to the antithrombotic drug heparin was studied by fluorescence spectroscopy in solution. The polyanionic polysaccharide strands of heparin bind more probe molecules per sugar unit when the charge of the latter is low, and stability of the probe-heparin complex increases with increasing probe charge.     

The Gender Gap in Second Language Acquisition: Gender Differences in the Acquisition of Dutch among Immigrants from 88 Countries with 49 Mother Tongues

Gender differences were analyzed across countries of origin and continents, and across mother tongues and language families, using a large-scale database, containing information on 27,119 adult learners of Dutch as a second language. Female learners consistently outperformed male learners in speaking and writing proficiency in Dutch as a second language. This gender gap remained remarkably robust and constant when other learner characteristics were taken into account, such as education, age of arrival, length of residence and hours studying Dutch. For reading and listening skills in Dutch, no gender gap was found. In addition, we found a general gender by education effect for all four language skills in Dutch for speaking, writing, reading, and listening. Female language learners turned out to profit more from higher educational training than male learners do in adult second language acquisition. These findings do not seem to match nurture-oriented explanatory frameworks based for instance on a human capital approach or gender-specific acculturation processes. Rather, they seem to corroborate a nature-based, gene-environment correlational framework in which language proficiency being a genetically-influenced ability interacting with environmental factors such as motivation, orientation, education, and learner strategies that still mediate between endowment and acquiring language proficiency at an adult stage.     

Endogenous Murine BST-2/Tetherin Is Not a Major Restriction Factor of Influenza A Virus Infection

BST-2 (tetherin, CD317, HM1.24) restricts virus growth by tethering enveloped viruses to the cell surface. The role of BST-2 during influenza A virus infection (IAV) is controversial. Here, we assessed the capacity of endogenous BST-2 to restrict IAV in primary murine cells. IAV infection increased BST-2 surface expression by primary macrophages, but not alveolar epithelial cells (AEC). BST-2-deficient AEC and macrophages displayed no difference in susceptibility to IAV infection relative to wild type cells. Furthermore, BST-2 played little role in infectious IAV release from either AEC or macrophages. To examine BST-2 during IAV infection in vivo, we infected BST-2-deficient mice. No difference in weight loss or in viral loads in the lungs and/or nasal tissues were detected between BST-2-deficient and wild type animals. This study rules out a major role for endogenous BST-2 in modulating IAV in the mouse model of infection.     

Production of a highly glucose tolerant β-glucosidase by Paecilomyces variotii MG3: optimization of fermentation conditions using Plackett–Burman and Box–Behnken experimental designs

β-Glucosidases (β-d-glucoside glucohydrolase, 3.2.1.21) are a group of enzymes mainly involved in the hydrolysis of β-glycosidic bonds connecting carbohydrate residues in different classes of β-d glycosides. During cellulose degradation they convert cellobiose and cellooligosaccharides produced by the endo and exoglucanases to glucose. Most of the microbial β-glucosidases are inhibited by glucose. This limits their application in commercial scale cellulose degradation ventures. Solid state fermentation production of a highly glucose tolerant β-glucosidase by a novel isolate of Paecilomyces was optimized using a two step statistical experiment design. In the first step which employed a Plackett–Burman design, the effects of parameters such as moisture, temperature, pH, inoculum concentration, incubation time and different concentrations of (NH₄)₂SO₄, KH₂PO₄, NaCl, peptone and cellobiose were evaluated. The parameters with significant influence on the process were selected and fine tuned in the second step using a Box–Behnken design. The model obtained was validated and a peptone concentration of 2 g/l, inoculum concentration of 1.2 × 10⁶ spores/ml and an incubation period of 96 h were found to be optimum for the maximum production of the enzyme. The optimization resulted in a doubling of the enzyme production by the fungus.