Efficient transgenic plant regeneration throughAgrobacterium-mediated transformation of Chickpea (Cicer arietinum L.)

Three genotypes of chickpea ICCV-1, ICCV-6 and a Desi (local) variety were tested for plant regeneration through multiple shoot production. The embryo axis was removed from mature seeds, the root meristem and the shoot apex were discarded. These explants were cultured on medium containing MS macro salts, 4X MS micro salts, I35 vitamins, 3.0 mg/1 BAP, 0.004 mg/1 NAA, 3% (w/v) sucrose and incubated at 26⁰C. The explants were transformed withAgrobacterium tumefaciens strain LBA4404 with binary vector pBI121 containing theuidA andnptIl genes. Multiple shoots were repeatedly selected with kanamycin. The selected kanamycin resistant shoots were rooted on MS medium supplemented with 0.05 mg/1 113A. The presumptive transformants histochemically stained positive for GUS. Additionally, nptll assay confirmed the expression ofnptII in kanamycin resistant plants. Transgenic plants were transferred to soil and grown in the green house.Abbreviations BAP 6-benzylamino purine - 2,4-D 2,4dichlorophenoxy acetic acid - IAA Indole acetic acid - IBA Indole butaric acid - NAA Naphthalene acetic acid     

Cold requirement for maximal activity of the bacterial ice nucleation protein INAZ in transgenic plants

The bacterial ice nucleation gene inaZ confers production of ice nuclei when transferred into transgenic plants. Conditioning of the transformed plant tissue at temperatures near 0°C greatly increased the ice nucleation activity in plants, and maximum ice nucleation activity was achieved only after low-temperature conditioning for about 48 h. Although the transgenic plants contain similar amounts of inaZ mRNA at both normal and low temperatures, low temperatures are required for accumulation of INAZ protein. We propose that the stability of the INAZ protein and thus ice nucleation activity in the transgenic plants is enhanced by low-temperature conditioning.     

Disparate modulation of plasma membrane protein lateral mobility by various cell permeabilizing agents

The mobility of a cell surface protein on cells osmotically swollen by treatment with several different cell permeabilizing agents retains specific restraints despite detachment of the plasma membrane from the cortical cytoskeleton. Fluorescence photobleaching recovery experiments indicate that the lateral diffusion constants of immunoglobulin E (IgE)-receptor complexes on the surface of rat basophilic leukemia cells increase 2–5 × following permeabilization with streptolysin O or digitonin, with little change in their mobile fractions. Swelling by hypo-osmotic treatment in water enhances lateral diffusion of IgE-receptor complexes and raises the mobile fractions to near 100%. In contrast, swelling by treatment with filipin arrests lateral diffusion, although rotational mobility remains unhindered. Lateral mobility of a fluorescent lipid analogue remains unchanged under these conditions. Crosslinking by anti-IgE antibodies redistributes the IgE-receptor complexes into large patches on untreated cells and on cells swollen by permeabilization with streptolysin O or digitonin, but rot on cells swollen by treatment with filipin. The results indicate a diversity of effects of the various permeabilizing agents on the mobility of membrane proteins. In particular, treatment with filipin appears to reorganize the plasma membrane into a network of fluid domains on a scale smaller than the bleaching spot size used (～1.5 μm). © 1994 Wiley-Liss, Inc.     

The functional units of a peptostreptococcal protein L

Protein L is a cell-surface protein from Peptostreptococcus which interacts with immunoglobulin kappa light chains. A gene from Peptostreptococcus strain 3316 coding for protein L and fragments thereof were expressed in Escherichia coli. The peptides were examined for binding to immunoglobulin and serum albumin. The four C units were shown to be responsible for binding to immunoglobulin and the four D units for binding to albumin. This protein L molecule therefore binds to albumin at a site separate from that involved in binding to immunoglobulin. The albumin-binding units have high amino acid sequence identity with the albumin-binding units of streptococcal cell-surface proteins. The gene contains three sites available for internal initiation of translation resulting in three active proteins. The protein L molecule presented in this report was compared with a previously reported protein from Peptostreptococcus strain 312. The two proteins differ in several respects, including size and the number and types of repeat units.     

Effects of work and diet on progesterone secretion, short luteal phases and ovulations without estrus in postpartum F1 crossbred dairy cows

The effects of work and diet supplementation on progesterone secretion and on incidence of short luteal phases and ovulations without estrus was investigated in 40 postpartum F(1) crossbred dairy cows. These cows were allocated to 1 of 4 treatment groups: Group SPNW, supplement-nonworking; Group SPW, supplement-working; Group NSNW, nonsupplement-nonworking; and Group NSW, nonsupplement-working. After calving, working cows pulled sledges with a load of 300 to 450 Newtons(N); 4 hours per day 4 days per week, for a total of 100 days over a 1-year period. All cows were fed natural grass hay ad libitum while the supplemented cows were fed 3 kg of concentrate per head per day. The proportion of cows which showed behavioral estrus by 1 year post partum was 100, 100, 60 and 20% for Group SPNW, SPW, NSNW and NSW cows, respectively. Based on plasma progesterone concentrations, ovulation started 62 days earlier than onset of behavioral estrus. A total of 73 ovulations occurred by 1 year post partum. Forty-nine (67.1%) and 26 (32.9%) ovulations occurred in the supplemented and nonsupplemented cows while 33 (45.2%) and 40 (54.8%) ovulations occurred in the working and nonworking cows, respectively. Of the total ovulations, 26 (35.6%) were not associated with behavioral signs of estrus and occurred in 13 (32.5%) cows. The incidence of ovulation without estrus was higher (P<0.05) in working (42.4%) than in nonworking (30%) cows and in nonsupplemented (41.7%) than in supplemented (32.7%) cows. Short luteal phases occurred in 32.5% of the cows before the establishment of normal estrous cycles. In working cows, diet supplementation off-set the negative effect of work on the onset of estrus and conception. However, a relatively higher number of cows in Group SPW had ovulations without estrus before a normal estrous cycle was established. The incidence of short luteal phases or ovulations without estrus did not influence the pregnancy rate in subsequent normal estrus periods. In conclusion, in the supplemented cows, work did not influence the proportion of cows showing estrus and conceiving, but it significantly delayed the postpartum anestrus interval. In the nonsupplemented cows, reproductive activity was impaired in both working and nonworking cows, but was pronounced in working cows. However, once pregnancy was established there was no effect of work on the maintenance of pregnancy. Our study shows that with appropriate feeding regimens lactating crossbred cows could be used for draught purposes without any detrimental effects on fertility, but calving intervals would be extended. Finally, the physiological mechanisms involved in anestrus and ovulations without estrus and the significance of such phenomena in affecting postpartum reproductive performance and fertility in working cows require further investigation.