Presynaptic dense bars at neuromuscular synapses of the lobster,Homarus americanus

Summary The threedimensional ultrastructure of presynaptic dense bars was examined by serial section electron microscopy in the excitatory neuromuscular synapses of the accessory flexor muscle in the limbs of larval, juvenile, and adult lobsters. The cross-sectional profile of the dense bar resembles an asymmetric hourglass, the part contacting the presynaptic membrane being larger than that projecting into the terminal. The bar has a height of 55–65 nm and varies in length from 75–600 nm. In its dimensions it resembles the dense projections in the synapses of the CNS of insects and vertebrates. The usual location of these dense bars is at well defined synapses, though a few are found at extrasynaptic sites either in the axon or terminal. In the latter case the bars are close to synapse-bearing regions, particularly in the larval terminals, suggesting that the extrasynaptic bars denote early events in synapse formation. In all cases the bars are intimately associated with electron lucent, synaptic vesicles located on either side, in the indentation of its hourglass-shaped cross sectional profile. The vesicles occur along the length of the bar and contact the presynaptic membrane. Consequently the dense bar may serve to align the vesicles at the presynaptic membrane prior to exocytosis. A similar role has been suggested for the presynaptic dense bodies at the neuromuscular junction of the frog, where synaptic vesicles form a row on either side of this structure.Supported by Muscular Dystrophy Association of Canada and NSERCC. Generous use of laboratory facilities at Woods Hole was provided by the late Fred Lang     

Survival of two enterobacteria in feces buried in soil under field conditions.

Feces samples, inoculated with 10(6) Escherichia coli resistant to streptomycin and nalidixic acid and with 10(5) Salmonella typhimurium per g, were buried at five mountain field sites ranging from 2,005 to 2,730 m in elevation. Counts of each bacterium rose initially and then declined to 10(3) or 10(4) per g of feces in 8 weeks. The survival pattern was similar at all sites regardless of marked differences in elevation, soil, moisture, exposure, and vegetation. S. typhimurium numbers were consistently higher than E. coli numbers after week 3. The test encompassed most of the time that the area is snow-free and accessible for hiking. The results were judged to discredit the recommendation for shallow burial of feces and to indicate a potential health hazard under intensive use.     

Microfilament bundles in antheridial nuclei of Achlya ambisexualis E 87

This is the first report of intranuclear microfilaments within gametangial nuclei of oömycetous fungi. Longitudinal sections of four to six microfilaments were frequently observed in meiotic antheridial nuclei of Achlya ambisexualis. Each microfilament measured approximately 7–10 nm in diameter. Spindle tubules (25 nm in diameter) were also observed within some of the nuclei possessing microfilaments.     

The antagonism by anti-inflammatory analgesics of prostaglandin F2α-induced contractions of human and rabbit myometrium

The anti-inflammatory analgesic drugs, aspirin, indomethacin, phenylbutazone, mefenamic acid, ibuprofen and flurbiprofen are shown to inhibit in a dose-dependent manner the force of contraction of isolated human pregnant myometrial strips which have been stimulated to contract by adding prostaglandin (PG) F_2α to the tissue bath. These drugs and also flufenamic acid and salicin show a similar antagonism of the action of PGF_2α with isolated rabbit non-pregnant myometrium. The ratio of the inhibitory concentration to the maximum plasma level after a normal dose suggests that phenylbutazone and possibly ibuprofen may be capable of inhibiting human uterine contractions . Patients who were treated with aspirin during induction of abortion using PGF_2α during the second trimester of pregnancy showed no significant change in the induction-abortion interval compared with patients not taking aspirin.     

Discriminability and preference among milking machine functions by dairy cows

An attempt was made to assess discomfort to the cow associated with milking machine function. Seven cows were presented with conditional discrimination tasks between alternative stimuli, using operant conditioning procedures. No discrimination between stimuli was evident. When allowed to choose between wide and narrow pulsation ratios, the 7 cows failed to do more than respond randomly. Four of the cows who were given a choice between potentially more or less aversive stimuli, pulsation vs. zero pulsation, showed no clear preference. The data suggest either that cows cannot discriminate within the experimental range of machine functions, i.e. that no measurable preference existed, or, under the experimental methods used, that cows could not learn the conditional discrimination required.     

Model-based design and control of a small-scale integrated continuous end-to-end mAb platform

A continuous integrated bioprocess available from the earliest stages of process development allows for an easier, more efficient and faster development and characterization of an integrated process as well as production of small-scale drug candidates. The process presented in this article is a proof-of-concept of a continuous end-to-end monoclonal antibody production platform at a very small scale based on a 200 ml alternating tangential flow filtration perfusion bioreactor, integrated with the purification process with a model-based design and control. The downstream process, consisting of a periodic twin-column protein A capture, a virus inactivation, a CEX column and an AEX column, was compactly implemented in a single chromatography system, with a purification time of less than 4 hr. Monoclonal antibodies were produced for 17 days in a high cell density perfusion culture of CHO cells with titers up to 1.0 mg/ml. A digital twin of the downstream process was created by modelling all the chromatography steps. These models were used for real-time decision making by the implementation of control strategies to automatize and optimize the operation of the process. A consistent glycosylation pattern of the purified product was ensured by the steady state operation of the process. Regarding the removal of impurities, at least a 4-log reduction in the HCP levels was achieved. The recovery yield was up to 60%, and a maximum productivity of 0.8 mg/ml/day of purified product was obtained.