Background Skeletal muscle growth and maintenance are essential for human health. One of the muscle regulatory genes, namely myostatin, a member of transforming growth factor-β, plays a dominant role in the genetic control of muscle mass. Myostatin is synthesized as a precursor protein, which generates the N-terminal propeptide and the C-terminal mature myostatin peptide by a post-translational cleavage event. Previously, transgenic over-expression of myostatin propeptide in skeletal muscle results in significant muscle growth in early stages of development. The objectives of present study were to further characterize muscle growth in later stages of life and to identify genes and their expression patterns that are responsible for adult muscle build-up by myostatin propeptide. Results Immunohistochemical staining with an antibody to the N-terminus indicates a high level of myostatin propeptide present in the muscles of transgenic mice while there were no apparent differences in myostatin protein distribution in the muscle fibers between the transgenic and wild-type mice. Main individual muscles increased by 76–152% in the transgenic mice over their wild-type littermate mice at 12 months of age. A large number of nuclei were localized in the central and basal lamina of the myofibers in the transgenic mice as the number of nuclei per fiber and 100 μm 2 area was significantly higher in transgenic mice than wild-type mice. By systemic comparisons of global mRNA expression patterns between transgenic mice and wild-type littermates using microarray and qRT-PCR techniques, we have identified distinct gene expression patterns to support adult muscle build-up by myostatin propeptide, which are comprised of enhanced expressions of myogenic regulatory factors and extracelullar matrix components, and differentially down-regulated expressions of genes related to protein degradation and mitochondrial ATP synthesis. Conclusion The results present a coordinated pattern of gene expressions for reduced energy utilization during muscle build-up in adult stage. Enhanced muscle buildup by myostatin propeptide is sustained by reduced ATP synthesis as a result of a decreased activity of protein degradation. Myostatin propeptide may have a therapeutic application to the treatment of clinical muscle wasting problems by depressing myostatin activity.

Abstract. Research was conducted to determine if directing expression of insulin-like growth factor I (IGF1) specifically to striated muscle would enhance lean muscle growth in swine. At 120 kg BW, 25 transgenic (T) and 26 control (C) pigs were sacrificed to evaluate carcass composition. T-pigs had lower percentages of fat and higher percentages of lean tissues than C-pigs for the overall carcass and each carcass region (P ≤ 0.002 for each). Expression of the IGF1 transgene did not alter the percentages of the three fiber types in the five skeletal muscles, however, fiber areas of longissimus dorsi muscle (LM) and serratus ventralis were larger (P ≤ 0.031) in T- than in C-pigs. In Tpigs the relative abundance of IGF1 mRNA in gastrocnemius, gluteus medius, LM, and the average for all five skeletal muscles (ASM) was positively (P ≤ 0.011) correlated with percentage of carcass lean (r = +0.597 to 0.804), whereas the relative abundance of IGF1 mRNA in the LM and the ASM was negatively (P ≤ 0.047) correlated with average backfat (r = −0.546 and −0.488, respectively). Based on these results we conclude that expression of IGF1 specifically in skeletal muscle had a positive effect on carcass composition of swine.

The bovine's long generation interval results in a delay of several years when evaluating mammary specific transgenes in genetically engineered animals. This experiment was conducted to evaluate the feasibility of reducing that waiting period. Lactation was induced in prepubertal bull and heifer calves as a means of predicting transgene behaviour during subsequent post-parturient lactations in the heifers themselves, and in daughters sired by the bulls. The animals carry a lactation-specific transgene encoding lysostaphin, an antimicrobial protein that kills Staphlococcus aureus , a mastitis-causing pathogen. Oestrogen, progesterone and dexamethasone were administered as previously described (Ball et al. 2000) to nine heifers (five transgenics) ranging in weight from 80 to 145 kg. Eight bull calves (seven transgenics) weighing 81–178 kg received additional oestrogen and progesterone injection prior to dexamethasone treatment. All nine heifers responded to the milk induction scheme yielding between 19 ml and 4·5 l over 5 d. Milk volume from the four responding males (30 μl to 2·5 ml) was significantly less than that harvested from females ( P =0·025). Only bull calves >117 kg had a positive response. Lysostaphin was detected in all transgenic prepubertal heifers and in two transgenic prepubertal bull calves induced. A positive relationship was observed between lysostaphin's stapholytic activity in the two types of lactations ( r 2 =0·907, P <0·001) thus providing a useful means of predicting subsequent lysostaphin production in post-partum milk.

Mastitis is a disease of the mammary gland caused by pathogens that find their way into the lumen of the gland through the teat canal. Mammary gland infections cost the US dairy industry approximately $2 billion dollars annually and have a similar impact in Europe. In the absence of effective treatments or breeding strategies to enhance mastitis resistance, we have created transgenic dairy cows that express lysostaphin in their mammary epithelium and secrete the antimicrobial peptide into milk. Staphylococcus aureus, a major mastitis pathogen, is exquisitely sensitive to lysostaphin. The transgenic cattle resist S. aureus mammary gland challenges, and their milk kills the bacteria, in a dose dependent manner. This first step in protecting cattle against mastitis will be followed by introduction of other genes to deal with potential resistance issues and other mastitis causing organisms. Care will be taken to avoid altering milk’s nutritional and manufacturing properties. Multi-cistronic constructs may be required to achieve our goals as will other strategies possibly involving RNAi and gene targeting technology. This work demonstrates the possibility of using transgenic technology to address disease problems in agriculturally important species.

Nat. Biotechnol. 23, 445–451 (2005) In the abstract on page 445, the quantities given for lysostaphin in the following sentences are incorrect: “To test the feasibility of protecting animals through genetic engineering, transgenic cows secreting lysostaphin at concentrations ranging from 0.9 to 14 mg/ml in their milk were produced” and “Protection against S.

In an anechoic chamber normal-hearing subjects performed a localization task in the frontal horizontal plane. The stimulus was a 200-ms burst of filtered noise. Within a block of trials, half of the presentations (randomly determined) were ‘‘real’’—presented from single loudspeakers—and the other half were ‘‘phantoms’’—produced by the simultaneous activation of two loudspeakers at ±30° using a virtual source imaging technique [Takeuchi et al., J. Acoust. Soc. Am. 109, 958–971 (2001)]. Both phantom and real sources spanned the azimuthal range ±80°. When the stimulus was a 4 kHz low-pass filtered noise, rms error was only slighly higher for phantom (D̄=7.1°) than for real (D̄=5.5°) sources. For 8 kHz low-pass filtered noise, performance remained about the same for real sources, but increased for phantom sources (D̄=11.5°). Data will also be reported for conditions in which the subject’s position is systematically varied outside the ‘‘sweet spot.’’ Results will be discussed in terms of robustness of the virtual imaging technique to stimulus and position factors and its potential usefulness as a tool for the investigation of human auditory spatial perception in static and dynamic environments. [Work supported by NIDCD.]

A series of experiments was conducted to evaluate factors influencing the effectiveness of audible pedestrian signals for providing useful intersection crossing information for pedestrians with visual impairments. Participants crossed a 20 m outdoor space that simulated the width of a four lane crossing with a background noise level comparable to normal traffic. The most robust effect in the provision of audible pedestrian signals was providing the signal from the far side of a crosswalk only as opposed to from both sides simultaneously or alternating between the two sides. Another strong benefit was seen from providing auditory guidance through the pedestrian clearing phase. Other results indicate that the type of signal used is not a major factor in guiding pedestrians across the street; however, the placement and alignment of the speaker on the street corner can have a large impact on both guiding pedestrians across the street and indicating which crosswalk is being signaled.

As an initial step towards enhancing mastitis resistance in dairy animals, we generated BLG-Lys transgenic mice that secrete lysostaphin, a potent antistaphylococcal protein, in their milk. In the current study, we continue our assessment of lysostaphin as a suitable antimicrobial protein for mastitis resistance and have investigated mammary gland development and function in three lines of transgenic mice. As the lines were propagated, there was a tendency for fewer BLG-Lys litters to survive to weaning (51% as compared to 90% for nontransgenic lines, p = 0.080). Nontransgenic pups fostered on dams from these three lines exhibited diminished growth rates during the first week of lactation. Rates of gain became comparable to pups on nontransgenic dams at later time points. Initial slow growth also resulted in decreased weaning weights for pups nursed by transgenic dams (15.35±0.27 g) when compared to pups delivered and nursed by nontransgenic dams (18.61 ± 0.61 g; p < 0.001), but the effect was temporary, as similar weights were attained by adulthood. Milk yield at peak lactation was not different between BLG-Lys (0.79 ± 0.33 g) and nontransgenic (0.91 ± 0.38 g; p = 0.166) dams. Histological examination of the transgenic mammary glands during gestation revealed no differences when compared to control glands; however, at early lactational stages, the BLG-Lys glands exhibited less alveolar area than control glands and a delay in lobulo-alveolar maturation. The results clearly demonstrate reduced growth of neonates on BLG-Lys dams; whether the poor pup performance can be attributed to delayed mammary development or the gland development merely reflects reduced suckling stimuli from the pups remains to be determined.

This paper introduces a new method for explaining the predictions of ensembles of neural networks on a case by case basis. The approach of explaining individual examples differs from much of the current research which focuses on producing a global model of the phenomenon under investigation. Explaining individual results is accomplished by modelling each of the networks as a rule-set and computing the resulting coverage statistics for each rule given the data used to train the network. This coverage information is then used to choose the rule or rules that best describe the example under investigation. This approach is based on the premise that ensembles perform an implicit problem space decomposition with ensemble members specialising in different regions of the problem space. Thus explaining an ensemble involves explaining the ensemble members that best fit the example.

A survey of braille transcribers in 40 states found that braille production systems rely on volunteers and hence that braille transcription is not considered a bona fide career. Issues of certification, training, availability, and definition are all related to this central issue.

This survey found a wide range of capabilities and issues regarding the production of textbooks and instructional materials for students with visual impairments in 42 states. Shortages of qualified braille transcribers and inadequate funding were often cited as barriers to developing better services. The most effective model of production and delivery was a centralized center in each state.

This survey of the use of technology and multimedia presentations by 410 teachers of students with visual impairments found that the teachers were more at ease with general technology than with technology designed specifically for students with visual impairments. When adapting traditional materials, the teachers tended to use simpler, less technological solutions even when they were not entirely appropriate.

Infection of the mammary gland, in addition to causing animal distress, is a major economic burden of the dairy industry. Staphylococcus aureus is the major contagious mastitis pathogen, accounting for approximately 15–30% of infections, and has proved difficult to control using standard management practices. As a first step toward enhancing mastitis resistance of dairy animals, we report the generation of transgenic mice that secrete a potent anti-staphylococcal protein into milk. The protein, lysostaphin, is a peptidoglycan hydrolase normally produced by Staphylococcus simulans . When the native form is secreted by transfected eukaryotic cells it becomes glycosylated and inactive. However, removal of two glycosylation motifs through engineering asparagine to glutamine codon substitutions enables secretion of Gln 125,232 -lysostaphin, a bioactive variant. Three lines of transgenic mice, in which the 5′-flanking region of the ovine β-lactoglobulin gene directed the secretion of Gln 125,232 -lysostaphin into milk, exhibit substantial resistance to an intramammary challenge of 10 4 colony-forming units (c.f.u.) of S. aureus , with the highest expressing line being completely resistant. Milk protein content and profiles of transgenic and nontransgenic mice are similar. These results clearly demonstrate the potential of genetic engineering to combat the most prevalent disease of dairy cattle.

Last year marked the 20th anniversary of the invention of the term "transgenic" and the development of pronuclear microinjection, a straightforward technique designed to transfer genetic information from nearly any living organism to mammals. After two decades of use, pronuclear microinjection protocols have changed little from the reliable, if not efficient, method described by Gordon and Ruddle. Experience has taught us that once microinjection skills are perfected there are only a few parameters one needs to be concerned about to successfully produce transgenic animals. Those parameters will be discussed, as will some new innovations that promise to finally increase efficiency of pronuclear microinjection methodology.

Optical devices were prescribed and training provided for children with low vision in the state of Tennessee. Reading rates and comprehension rates were taken before introduction of the optical devices and after approximately six months of using the aids. Scores were also recorded of student, teacher, and parent expectations of the students' visual functioning. Data show that students did not make significant changes in their silent or oral reading rates. However, it is important to note that they did make significant gains in comparison to the reading norms of their sighted peers. Data also show that expectation of students' visual functioning increased in both students and their teachers. In contrast, parents' expectations of students' visual functioning decreased.