Different Seed Selection and Conservation Practices for Fresh Market and Dried Chile Farmers in Aguascalientes,Mexico

Different Seed Selection and Conservation Practices for Fresh Market and Dried Chile Farmers in Aguascalientes, Mexico. The process of selecting and saving seed is the most basic and oldest of agricultural practices. In today’s modern and highly capital-intensive agriculture, seeds are often treated like another chemical input. This study sought to examine seed selection and saving practices among chile farmers in Aguascalientes, Mexico, where both industrial and traditional agriculture are practiced. We observed a clear division among farmers who plant chile peppers commercially. Sixty-eight chile pepper farmers were surveyed in order to document seed selection and saving practices. Fifteen respondents (22%) planted chile peppers destined for the fresh market and all utilized purchased commercial seed of F1 hybrid varieties. Fifty-three farmers (78%) planted chiles to be dried and either saved their own or purchased seeds that others had saved and selected. Farmers who saved their own seed sought to maintain an ideotype, rather than directionally select for certain traits, much like Cleveland et al. (2000) chronicled in central Mexican maize farmers. Farmers would benefit from a participatory plant-breeding program in order to maintain productive seed stock for the continued cultivation of dried chile pepper in the state.     

T cells from nonresponder mice. MHC restricted and unrestricted recognition of insulin

Two types of insulin-reactive T cell hybridomas expressing TCR-alpha beta were derived from nonresponder H-2b mice immunized with pork insulin. One type had characteristics of conventional class II-restricted Th cells. These CD4+ CD8- I-Ab-restricted T cells recognized a self determinant, present within the insulin B-chain. This determinant was distinct from the immunodominant A-chain loop determinant that is recognized by the majority of T cells induced after immunization with normally immunogenic beef insulin. Our results suggest that this determinant is readily generated during immunologic processing of insulins, including nonimmunogenic pork insulin and self insulin. A second type of T cell lacking CD4 and CD8 recognized a distinct B-chain determinant of insulin in a class II-dependent, but MHC unrestricted, fashion. These cells may represent a novel subpopulation which has bypassed conventional selection during development in the thymus.     

Dioxygen and temperature dependence of ubiquinone formation in Escherichia coli: studies of cells charged with 2-octaprenyl phenol.

The multiple aromatic auxotroph Escherichia coli K-12 strain AB 2847 (aroB-) was conditioned for efficient ubiquinone-8 formation. Resting cells readily convert 4-hydroxy[U-14C]benzoate into ubiquinone-8 (60 nmol per g wet weight). Under argon this processing stops at the stage of 2-octaprenyl phenol. Only upon admission of air is the pool of 2-octaprenyl phenol converted to ubiquinone-8. This reaction occurs in the cytoplasmic membrane and is significantly inhibited by cytochrome P-450 inhibitors. The rate for 2-octaprenyl phenol conversion is strongly dependent on temperature. The Arrhenius plot shows inflection points at 32 degrees C and 16 degrees C. Enzymes for ubiquinone-8 synthesis are absent from anaerobically grown E. coli. Processing of 4-hydroxy[U-14C]benzoate by these cells starts only when protein synthesis is permitted under aerobic conditions.     

Diagnosis of murine infections in relation to test methods employed

Comparative investigations of Sendai virus, pneumonia virus of mice (PVM), mouse encephalomyelitis virus (mouse polio), minute virus of mice (MVM), and reovirus type 3 (Reo 3) infected murine colonies revealed a 30% higher incidence of positive sera when enzyme-linked immunosorbent assay (ELISA) was employed instead of hemagglutination inhibition (HI) tests. Equivalent sensitivity as in the ELISA was obtained when the same sera were investigated by indirect immunofluorescence (IF) tests. The virus purification techniques described resulted in highly suitable antigens for all indirect ELISA established. Since IIF requires no purified antigens, this test is recommended as an alternative to ELISA as well as to HI and complement fixation (CF) tests for laboratories lacking the necessary equipment for high speed centrifugation. A high incidence of false positive HI reactions was found particularly in Reo 3 routine serology. An updated survey of seromonitoring showed that European murine colonies appeared to be infected far less with Reo 3 if ELISA or IIF tests were employed. During 1982-1984, only 13% of the mouse colonies screened possessed Reo 3 positive sera whereas no natural Reo 3 infection was found in rat colonies. Mouse hepatitis virus (MHV) and the coronaviruses of rats exhibited the highest incidence in murine colonies. A total of 60% of mouse and 41% of rat colonies were found to be infected by these viruses. In comparison with earlier serological surveys, the relative incidence of other murine infections was similar. Antibodies against Bacillus piliformis (Tyzzer's disease) were detected by the IIF test in 41% of the rat colonies screened.     

Steroid-1-dehydrogenase of Rhodococcus erythropolis: purification and N-terminal amino acid sequence.

The inducible steroid-1-dehydrogenase from the bacterium Rhodococcus erythropolis IMET 7030 was purified to homogeneity using affinity chromatographic, electrophoretic, and ion exchange techniques. The spectrum of the pure enzyme is characterized by the associated FAD. The M(r) of the enzyme is 56,000. The amino acid composition and the sequence of the 13 N-terminal amino acids are given.     

Growth and taxonomy of bull charr,Salvelinus confluentus,in Pinto Lake,Alberta

Synopsis Morphometric and meristic information confirmed the Salvelinus in Pinto Lake, Alberta, to be bull charr. The population was essentially electrophoretically monomorphic. Sub-yearling bull charr in Pinto Lake grew more slowly than fish from other populations in Alberta. Growth rate after the first year appeared to be linear until age 8 when growth declined. Concern was raised about the problem of anglers overexploiting the population.     

Combination of static-field gel electrophoresis and densitometric scanning for the determination of radiation-induced DNA double-strand breaks in CHO cells

An experimental setup using static-field gel electrophoresis (SFGE) was developed to determine radiation-induced DNA double-strand breaks (DSBs) in CHO-K1 cells after exposure to X-rays or heavy charged particles. The fraction of DNA eluted into the gel matrix depends on the quantity of DSBs introduced. In agreement with a recent report, SFGE and pulsed-field electrophoresis were found to be equally sensitive in DSB detection. With radiolabeled DNA from cell cultures, the absolute amount of DNA migrating out of agarose plugs into the gel was quantified by determining the radioactivity in the gel lane. Alternatively, relative measurements of the amount of DNA released into the gel were achieved with a standardized protocol for both SFGE and a subsequent densitometric scanning of photographic negatives from gels stained with ethidium bromide. After calibration with the radioactive method, the fractions of DNA retained could be calculated directly from the data obtained with the densitometric assay to set up classical dose-effect curves. This procedure was validated for its application with heavy ions using an 500 MeV/u lead beam.     

A glycosylated recombinant human granulocyte colony stimulating factor produced in a novel protein production system (AVI-014) in healthy subjects: a first-in human, single dose, controlled study

Background  

AVI-014 is an egg white-derived, recombinant, human granulocyte colony-stimulating factor (G-CSF). This healthy volunteer study is the first human investigation of AVI-014.     

On the existence of two populations of mitochondria in a single organ. Respiration, calcium transport and enzyme activities.

Mitochondria isolated from rat heart and kidney cortex by Polytron treatment of the tissues exhibit lower state 3 rates of respiration than mitochondria isolated by Nagarse method. Addition of cytochrome $\text{c}$ to Polytron mitochondria isolated from heart, but not from kidney, increases oxygen uptake to values approaching those of Nagarse-treated preparations. Similar results were observed for Ca²⁺ uptake. Kidney Polytron mitochondria exhibited lower mitochondrial, but higher non-mitochondrial enzyme activities compared to kidney Nagarse mitochondria. Enzyme activities were the same in Polytron and Nagarse mitochondria from heart. The differences between Polytron and Nagarse mitochondria appear to be mainly due to lower cytochrome $\text{c}$ content of Polytron mitochondria from heart and higher contamination of Polytron mitochondria from kidney.