Contraction properties and motor nucleus morphology of the two heads of the cat flexor carpi ulnaris muscle

Previous studies have examined the isometric contraction properties of the two heads of the cat flexor carpi ulnaris acting as a single unit. In this study, the contraction properties and fiber architecture of each head of the flexor carpi ulnaris were determined separately and related to previous reports on the histochemical characteristics of this muscle. The morphology of retrograde-labeled motor nuclei for the two heads of the muscle was also examined. The humeral head had a significantly longer contraction time (48 msec) than the ulnar head (36 msec) as well as a significantly lower tetanic fusion frequency (28 Hz vs. 35 Hz). The maximum tetanic tension per gram of muscle tissue was 71% greater in the ulnar head. Motoneurons of the flexor carpi ulnaris formed a column 12 mm long and 0.5 mm wide in the center of the ventral grey in spinal segments C8 and T1. The ulnar head had alpha-motoneurons with greater soma diameters than those in the humeral head. The smaller soma diameter, slower contraction time, and weaker contraction in the humeral head correlate with the preponderance of oxidative-metabolic muscle fiber types found in the humeral head by other workers. These correlations suggest that the humeral head plays a major role in maintaining a sustained antigravity tension that prevents the wrist from buckling during standing.     

Broomrape (Orobanche) seed germination inhibitors from plant roots

Two species (tomato and cucumber) which are not hosts to Orobanche crenata but which are hosts to other species of Orobanche not only failed to produce the compound required to trigger O. crenata to germinate but produced germination inhibitors which stopped germination even in the presence of a suitable stimulant. This suggested the possibility of using germination inhibitors to control at least some species of Orobanche. The question whether host species produce inhibitors as well as stimulants has not however been resolved.     

Ribosomal subunits and ribosomal proteins of Tetrahymena thermophila. Effect of the presence of iodoacetamide during ribosome extraction on the properties of the subunits

Proteolytic degradation of ribosomal proteins occurs during the preparation of subunits of the cytoplasmic ribosomes of the protozoa Tetrahymena thermophila and the isolated subunits are inactive. Addition of 5 mM iodoacetamide to cell suspensions before extraction inhibits proteolytic activity and permits isolation of active subunits. The protein complements of these subunits have been characterized in two different two-dimensional electrophoretic systems, and their molecular weights have been determined.     

Drivers of Vaginal Drug Delivery System Acceptability from Internet-Based Conjoint Analysis

Vaginal microbicides potentially empower women to protect themselves from HIV and other sexually transmitted infections (STIs), especially when culture, religion, or social status may prevent them from negotiating condom use. The open literature contains minimal information on factors that drive user acceptability of women’s health products or vaginal drug delivery systems. By understanding what women find to be most important with regard to sensory properties and product functionality, developers can iteratively formulate a more desirable product. Conjoint analysis is a technique widely used in market research to determine what combination of elements influence a consumer’s willingness to try or use a product. We applied conjoint analysis here to better understand what sexually-active woman want in a microbicide, toward our goal of formulating a product that is highly acceptable to women. Both sensory and non-sensory attributes were tested, including shape, color, wait time, partner awareness, messiness/leakage, duration of protection, and functionality. Heterosexually active women between 18 and 35 years of age in the United States (n = 302) completed an anonymous online conjoint survey using IdeaMap software. Attributes (product elements) were systematically presented in various combinations; women rated these combinations of a 9-point willingness-to-try scale. By coupling systematic combinations and regression modeling, we can estimate the unique appeal of each element. In this population, a multifunctional product (i.e., broad spectrum STI protection, coupled with conception) is far more desirable than a microbicide targeted solely for HIV protection; we also found partner awareness and leakage are potentially strong barriers to use.     

Discontinuous genetic variation among mesophilic Naegleria isolates: further evidence that N. gruberi is not a single species.

Naegleria isolates which are currently placed in the type species N. gruberi display great genetic, physiological and morphological heterogeneity. There are two possible interpretations of the nature of this species--that N. gruberi is a species complex or that it is a single continuously variable species. To distinguish between these alternatives, allelic states were determined for 33 loci in 74 new isolates selected to represent wide geographic sources and diverse temperature limits for growth. The results were compared with data for culture collection strains of N. gruberi and other species in the genus. The isolates formed a discontinuous series of clusters, separated by genetic distances similar to those separating the better-characterised taxa N. fowleri, N. lovaniensis, N. jadini, N. australiensis australiensis and N. australiensis italica. Culture collection strains assigned to N. gruberi fell into six distinct clusters, while other clusters were not represented by reference strains. The data are most consistent with the interpretation that N. gruberi is a group of several distinct species, each equivalent to the recently described species in the genus. Naegleria andersoni andersoni and N. andersoni jamiesoni also formed two distinct clusters, equivalent to species. Characteristics temperature limits for growth show that the mesophilic species are ecological as well as genetic entities.     

Segmented arrangement of Borrelia duttonii DNA and location of variant surface antigen genes

The DNA of an isolate of Borrelia duttonii, an agent of relapsing fever is present as seven major species ranging in size from 10 kb to greater than 150 kb. Additionally, this isolate contains low copy number species, both smaller and larger than these seven major elements. No one of these individual DNA species obviously corresponds to the bacterial chromosome, unlike the situation in Borrelia hermsii, another relapsing fever Borrelia. Thus it appears that B. duttonii has a unique segmented arrangement of its genetic material. Cloned DNA fragments containing coding sequences specific for variant surface antigens of B. duttonii hybridize to a closely migrating, high copy number subset of these genetic elements.