Trematode parasites as indicators of an animal component in the diet of the Water Vole Arvicola amphibius.

The intestinal trematode fauna of the Water Vole Arvicola amphibius, (previously A. terrestris), was investigated to determine whether it might provide evidence of an animal component in the diet of this aquatic herbivorous small mammal. Interrogation of the electronic Host-Parasite Database of the Natural History Museum London revealed the presence of fourteen species of intestinal trematode in water voles, infection with each of which would require the ingestion of tissue from an animal intermediate host. The results obtained using these parasite indicators provide convincing evidence of animal components in the diet of A. amphibius and support anecdotal reports of water voles feeding on animal material in the field.

Rapid sperm capture: high-throughput flagellar waveform analysis.

STUDY QUESTION: Can flagellar analyses be scaled up to provide automated tracking of motile sperm, and does knowledge of the flagellar waveform provide new insight not provided by routine head tracking? SUMMARY ANSWER: High-throughput flagellar waveform tracking and analysis enable measurement of experimentally intractable quantities such as energy dissipation, disturbance of the surrounding medium and viscous stresses, which are not possible by tracking the sperm head alone. WHAT IS KNOWN ALREADY: The clinical gold standard for sperm motility analysis comprises a manual analysis by a trained professional, with existing automated sperm diagnostics [computer-aided sperm analysis (CASA)] relying on tracking the sperm head and extrapolating measures. It is not currently possible with either of these approaches to track the sperm flagellar waveform for large numbers of cells in order to unlock the potential wealth of information enclosed within. STUDY DESIGN, SIZE, DURATION: The software tool in this manuscript has been developed to enable high-throughput, repeatable, accurate and verifiable analysis of the sperm flagellar beat. PARTICIPANTS/MATERIALS, SETTING, METHODS: Using the software tool [Flagellar Analysis and Sperm Tracking (FAST)] described in this manuscript, we have analysed 176 experimental microscopy videos and have tracked the head and flagellum of 205 progressive cells in diluted semen (DSM), 119 progressive cells in a high-viscosity medium (HVM) and 42 stuck cells in a low-viscosity medium. Unscreened donors were recruited at Birmingham Women's and Children's NHS Foundation Trust after giving informed consent. MAIN RESULTS AND THE ROLE OF CHANCE: We describe fully automated tracking and analysis of flagellar movement for large cell numbers. The analysis is demonstrated on freely motile cells in low- and high-viscosity fluids and validated on published data of tethered cells undergoing pharmacological hyperactivation. Direct analysis of the flagellar beat reveals that the CASA measure 'beat cross frequency' does not measure beat frequency; attempting to fit a straight line between the two measures gives ${\mathrm{R}}^2$ values of 0.042 and 0.00054 for cells in DSM and HVM, respectively. A new measurement, track centroid speed, is validated as an accurate differentiator of progressive motility. Coupled with fluid mechanics codes, waveform data enable extraction of experimentally intractable quantities such as energy dissipation, disturbance of the surrounding medium and viscous stresses. We provide a powerful and accessible research tool, enabling connection of the mechanical activity of the sperm to its motility and effect on its environment. LARGE SCALE DATA: The FAST software package and all documentation can be downloaded from www.flagellarCapture.com. LIMITATIONS, REASONS FOR CAUTION: The FAST software package has only been tested for use with negative phase contrast microscopy. Other imaging modalities, with bright cells on a dark background, have not been tested but may work. FAST is not designed to analyse raw semen; it is specifically for precise analysis of flagellar kinematics, as that is the promising area for computer use. Flagellar capture will always require that cells are at a dilution where their paths do not frequently cross. WIDER IMPLICATIONS OF THE FINDINGS: Combining tracked flagella with mathematical modelling has the potential to reveal new mechanistic insight. By providing the capability as a free-to-use software package, we hope that this ability to accurately quantify the flagellar waveform in large populations of motile cells will enable an abundant array of diagnostic, toxicological and therapeutic possibilities, as well as creating new opportunities for assessing and treating male subfertility. STUDY FUNDING/COMPETING INTEREST(S): M.T.G., G.C., J.C.K-B. and D.J.S. gratefully acknowledge funding from the Engineering and Physical Sciences Research Council, Healthcare Technologies Challenge Award (Rapid Sperm Capture EP/N021096/1). J.C.K-B. is funded by a National Institute of Health Research (NIHR) and Health Education England, Senior Clinical Lectureship Grant: The role of the human sperm in healthy live birth (NIHRDH-HCS SCL-2014-05-001). This article presents independent research funded in part by the NIHR and Health Education England. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The data for experimental set (2) were funded through a Wellcome Trust-University of Birmingham Value in People Fellowship Bridging Award (E.H.O.).The authors declare no competing interests.

Body Size Influences Stingless Bee (Hymenoptera: Apidae) Communities Across a Range of Deforestation Levels in Rondônia, Brazil.

Developments in understanding bee responses to habitat loss indicate that body size is a trait with important consequences for conservation. Stingless bees (Hymenoptera, Apidae, Meliponini) are a diverse group of eusocial bees providing pollination services in tropical landscapes, exhibiting a large range in body size across species. We tested the effects of deforestation on the body sizes of stingless bee communities by using museum specimens and revisiting a previous effort that sampled stingless bee communities across varying levels of deforestation at 183 sites in Rondônia, Brazil, in 1996-1997. Body size measurements (intertegular distance) from 72 species collected were included as dependent variables in response to forest area, forest edge, and connectivity of forest patches at several spatial scales. We find that stingless bee body size is negatively related to forest cover: mean community body size was larger in areas with greater amounts of deforestation, and smaller in areas with less deforestation. Second, stingless bee species richness was positively associated with forest edge regardless of body size. Lastly, we find that as forest patch isolation increased, the stingless bee community body size also increased. These findings support hypotheses that small stingless bee species might be more negatively affected by deforestation, adding to the growing body of evidence that stingless bees require areas of intact forest in near proximity to other forest patches to conserve these diverse pollinator communities.

CASA: tracking the past and plotting the future.

The human semen sample carries a wealth of information of varying degrees of accessibility ranging from the traditional visual measures of count and motility to those that need a more computational approach, such as tracking the flagellar waveform. Although computer-aided sperm analysis (CASA) options are becoming more widespread, the gold standard for clinical semen analysis requires trained laboratory staff. In this review we characterise the key attitudes towards the use of CASA and set out areas in which CASA should, and should not, be used and improved. We provide an overview of the current CASA landscape, discussing clinical uses as well as potential areas for the clinical translation of existing research technologies. Finally, we discuss where we see potential for the future of CASA, and how the integration of mathematical modelling and new technologies, such as automated flagellar tracking, may open new doors in clinical semen analysis.

The effectiveness of the nationwide BokSmart rugby injury prevention program on catastrophic injury rates.

Rugby Union ("rugby") participants have a higher than average risk of injury compared with participants of other popular team sports. BokSmart, a nationwide injury prevention program was launched in South Africa in mid-2009, with the goal of reducing catastrophic head/neck (serious) injuries in players. The program provides injury prevention information to coaches and referees. This study investigated if BokSmart has been associated with a reduction in these injuries. The BokSmart program collected data on all South African rugby-related serious injuries since 2008. Using a Poisson regression, injury numbers were compared pre-BokSmart (2008-2009) to the years post-implementation (2010-2013). Player numbers were assumed to be constant throughout this evaluation: junior = 529,483; senior = 121,663. In junior players, the "post-BokSmart" period had 2.5 less annual serious injuries than "pre-BokSmart" (incidence rate ratio: 0.6, 95% confidence interval: 0.5-0.7, P < 0.000). In contrast, there was no significant difference in these periods in seniors. The absence of effect in seniors may be a result of fewer players or of differences in effectiveness of BokSmart in this group--future studies should investigate these questions.

Physical function as a prognostic biomarker among cancer survivors.

BACKGROUND: We tested the hypothesis that objectively measured physical function predicts mortality among cancer survivors. METHODS: We assessed objectively measured physical function including the short physical performance battery (SPPB) and fast walk speed in older adult cancer survivors. RESULTS: Among 413 cancer survivors, 315 (76%) died during a median follow-up of 11.0 years. In multivariable-adjusted analyses, each 1-unit increase in the SPPB score and 0.1 m s(-1) increase in fast walk speed predicted a 12% reduction in mortality (hazard ratio (HR): 0.88 (95% confidence interval (CI): 0.82-0.94); P<0.001, and HR: 0.88 (95% CI: 0.82-0.96); P=0.003, respectively). CONCLUSIONS: Objectively measured physical function may predict mortality among cancer survivors.

The impact of vitamin D3 supplementation on muscle function among HIV-infected children and young adults: a randomized controlled trial.

OBJECTIVES: We tested the hypothesis that daily vitD3 supplementation increases neuromuscular motor skills, jump power, jump energy, muscular force, and muscular strength. METHODS: This was a secondary analysis of a randomized controlled trial of 12-months of oral 7,000 IU/day vitD3 supplementation or placebo among 56 persons living with HIV aged 9-25 years. Neuromuscular motor skills were quantified using the Bruininks-Oseretsky Test of Motor Proficiency. Power was quantified using peak jump power, and energy was quantified using peak jump height. Muscular force was quantified using isometric ankle plantar- and dorsiflexion, isokinetic knee flexion and extension. Muscular strength was quantified using isometric handgrip strength. RESULTS: After 12-months, serum 25-hydroxyvitamin D [25(OH)D] was higher with supplementation versus placebo (ß=12.1 ng/mL; P<0.001). In intention-to-treat analyses, supplementation improved neuromuscular motor skills versus placebo (ß=1.14; P=0.041). We observed no effect of supplementation on jump power, jump energy, muscular force, or muscular strength outcomes versus placebo. CONCLUSIONS: Among HIV-infected children and young adults supplementation with daily high-dose vitD3 increased concentration of serum 25(OH)D and improved neuromuscular motor skills versus placebo.

Vascular dysfunction in young, mid-aged and aged mice with latent cytomegalovirus infections.

Human cytomegalovirus (HCMV) is associated with vascular diseases in both immunosuppressed and immunocompetent individuals. CMV infections cycle between active and latent phases throughout life. We and others have shown vascular dysfunction during active mouse CMV (mCMV) infections. Few studies have examined changes in physiology during latent CMV infections, particularly vascular responses or whether the negative effects of aging on vascular function and fertility will be exacerbated under these conditions. We measured vascular responses in intact mesenteric and uterine arteries dissected from young, mid-aged, and aged latently mCMV-infected (mCMV genomes are present but infectious virus is undetectable) and age-matched uninfected mice using a pressure myograph. We tested responses to the α(1)-adrenergic agonist phenylephrine, the nitric oxide donor sodium nitroprusside, and the endothelium-dependent vasodilator methacholine. In young latently mCMV-infected mice, vasoconstriction was increased and vasodilation was decreased in mesenteric arteries, whereas both vasoconstriction and vasodilation were increased in uterine arteries compared with those in age-matched uninfected mice. In reproductively active mid-aged latently infected mice, mesenteric arteries showed little change, whereas uterine arteries showed greatly increased vasoconstriction. These vascular effects may have contributed to the decreased reproductive success observed in mid-aged latently mCMV-infected compared with age-matched uninfected mice (16.7 vs. 46.7%, respectively). In aged latently infected mice, vasodilation is increased in mesenteric and uterine arteries likely to compensate for increased vasoconstriction to mediators other than phenylephrine. The novel results of this study show that even when active mCMV infections become undetectable, vascular dysfunction continues and differs with age and artery origin.

Activities of muscadine grape skin and polyphenolic constituents against Helicobacter pylori.

AIMS: To identify active phenolic constituents in muscadine grape skin (MGS) extracts and determine interactions among compounds while further exploring their anti-Helicobacter pylori potential in vitro. METHODS AND RESULTS: The inhibitory effects of quercetin and resveratrol, active polyphenols identified in MGS extracts, against H. pylori were investigated. Quercetin and resveratrol significantly (P < 0.05) reduced H. pylori counts regardless of pH with minimal bactericidal concentrations of 256 and 128 µg ml(-1), respectively. MGS extracts displayed the highest efficacy, suggesting additional unidentified compounds not determined in this study. Time-course viability experiments showed a dose-dependent anti-H. pylori response to quercetin and resveratrol. Interestingly, neither quercetin nor resveratrol affected H. pylori outer membrane (OM) integrity as determined by 1-N-phenylnaphthylamine (NPN) uptake assays. However, treatment with MGS extract did increase NPN uptake, indicating OM destabilization possibly by additional unknown components. Furthermore, quercetin was found to enter H. pylori as measured by HPLC supporting intracellular drug accumulation. CONCLUSIONS: Quercetin and resveratrol possess strong anti-H. pylori activity in vitro and are independent of pH. Our results also suggest that these compounds do not affect H. pylori OM integrity as previously hypothesized and that the primary antimicrobial activity of quercetin may be linked to interactions with intracellular components. SIGNIFICANCE AND IMPACT OF THE STUDY: The anti-H. pylori effects of quercetin and resveratrol suggest that these compounds may be useful in the dietary prevention and/or treatment of H. pylori infection.

Modelling a tethered mammalian sperm cell undergoing hyperactivation.

The beat patterns of mammalian sperm flagella can be categorised into two different types. The first involves symmetric waves propagating down the flagellum with a net linear propulsion of the sperm cell. The second, hyperactive, waveform is classified by vigorous asymmetric waves of higher amplitude, lower wavenumber and frequency propagating down the flagellum resulting in highly curved trajectories. The latter beat pattern is part of the capacitation process whereby sperm prepare for the prospective penetration of the zona pellucida and fusion with the egg. Hyperactivation is often observed to initiate as sperm escape from epithelial and ciliary bindings formed within the isthmic regions of the female oviducts, leading to a conjecture in the literature that this waveform is mechanically important for sperm escape. Hence, we explore the mechanical effects of hyperactivation on a tethered sperm, focussing on a Newtonian fluid. Using a resistive force theory model we demonstrate that hyperactivation can indeed generate forces that pull the sperm away from a tethering point and consequently a hyperactivated sperm cell bound to an epithelial surface need not always be pushed by its flagellum. More generally, directions of the forces generated by tethered flagella are insensitive to reductions in beat frequency and the detailed flagellar responses depend on the nature of the binding at the tethering point. Furthermore, waveform asymmetry and amplitude increases enhance the tendency for a tethered flagellum to start tugging on its binding. The same is generally predicted to be true for reductions in the wavenumber of the flagellum beat, but not universally so, emphasising the dynamical complexity of flagellar force generation. Finally, qualitative observations drawn from experimental data of human sperm bound to excised female reproductive tract are also presented and are found to be consistent with the theoretical predictions.

Quantification of genes and gene transcripts for microbial perchlorate reduction in fixed-bed bioreactors.

AIMS: Optimization of full-scale, biological perchlorate treatment processes for drinking water would benefit from knowledge of the location and quantity of perchlorate-reducing bacteria (PRB) and expression of perchlorate-related genes in bioreactors. The aim of this study was to quantify perchlorate removal and perchlorate-related genes (pcrA and cld) and their transcripts in bioreactors and to determine whether these genes or transcripts could serve as useful biomarkers for perchlorate treatment processes. METHODS AND RESULTS: Quantitative PCR (qPCR) assays targeting pcrA and cld were applied to two pilot-scale, fixed-bed bioreactors treating perchlorate-contaminated groundwater. pcrA and cld genes per microgram of DNA were two- to threefold higher and three- to fourfold higher, respectively, in the bioreactor showing superior perchlorate-removal performance. In a laboratory-scale bioreactor, quantities of pcrA and cld genes and transcripts were compared under two distinct performance conditions (c.60 and 20% perchlorate removal) for a 5-min empty bed contact time. cld genes per microgram of DNA were approximately threefold higher and cld transcripts per microgram of RNA were approximately sixfold higher under the higher perchlorate-removal condition. No differences in pcrA genes or transcripts per microgram of DNA or RNA, respectively, were detected between the c.60 and 20% perchlorate-removal conditions, possibly because these assays did not accurately quantify pcrA genes and transcripts in the mixed culture present. CONCLUSIONS: Quantities of cld genes and transcripts per microgram of DNA and RNA, respectively, were found to be higher when perchlorate removal was higher. However, quantities of pcrA and cld genes or transcripts were not found to directly correlate with perchlorate-removal rates. SIGNIFICANCE AND IMPACT OF THE STUDY: To our knowledge, this study represents the first application of qPCR assays to quantify perchlorate-related genes and transcripts in continuous-flow bioreactors. The results indicate that cld gene and transcript quantities can provide insights regarding the quantity, location and gene expression of PRB in bioreactors.

The effect of trait self-control on dyspnoea and tolerance to a CO2 rebreathing challenge in healthy males and females.

BACKGROUND: High trait self-control is associated with greater tolerance of unpleasant sensations including effort and pain. Dyspnoea and pain have several commonalities and this study aimed to investigate for the first time whether trait self-control influences responses to a hypercapnic rebreathing challenge designed to induce dyspnoea. As sex also influences tolerance to dyspnoea, we also sought to investigate whether this moderated the role of trait self-control. METHODS: Participants (n = 65, 32 females) scoring high or low for trait self-control, performed a standardised rebreathing challenge, in which inspired carbon dioxide (CO2) gradually increased over a period of 6 min or until an intolerable level of dyspnoea. Air hunger (AH) intensity - a distinctive quality of dyspnoea, was measured every 30 s. The multidimensional dyspnoea profile (MDP) was completed after the rebreathing challenge for a more complete overview of breathing discomfort. RESULTS: Males high in trait self-control (SCHIGH) (302 ± 42 s), tolerated the rebreathing challenge for longer than males low in self-control (SCLOW) (252 ± 66 s, P = 0.021), experienced slower increases in AH intensity during the rebreathing challenge (0.03 ± 0.01 cm.s - 1 vs. 0.04 ± 0.01 cm.s - 1,P = 0.045) and reported lower perceived mental effort on the MDP (4.94 ± 2.46 vs. 7.06 ± 1.60, P = 0.007). There was no difference between SCHIGH and SCLOW females for challenge duration. However, SCHIGH females (9.29 ± 0.66 cm) reported greater air hunger at the end of the challenge than SCLOW females (7.75 ± 1.75 cm, P = 0.003). It is possible that SCLOW females were unwilling to tolerate the same perceptual intensity of AH as the SCHIGH females. CONCLUSIONS: These results indicate that individuals high in trait self-control are more tolerant of dyspnoea during a CO2 rebreathing challenge than low self-control individuals. Tolerance of the stimulus was moderated by the sex of the participant, presenting an interesting opportunity for future research.

Polymer formulated self-amplifying RNA vaccine is partially protective against influenza virus infection in ferrets.

COVID-19 has demonstrated the power of RNA vaccines as part of a pandemic response toolkit. Another virus with pandemic potential is influenza. Further development of RNA vaccines in advance of a future influenza pandemic will save time and lives. As RNA vaccines require formulation to enter cells and induce antigen expression, the aim of this study was to investigate the impact of a recently developed bioreducible cationic polymer, pABOL for the delivery of a self-amplifying RNA (saRNA) vaccine for seasonal influenza virus in mice and ferrets. Mice and ferrets were immunized with pABOL formulated saRNA vaccines expressing either haemagglutinin (HA) from H1N1 or H3N2 influenza virus in a prime boost regime. Antibody responses, both binding and functional were measured in serum after immunization. Animals were then challenged with a matched influenza virus either directly by intranasal inoculation or in a contact transmission model. While highly immunogenic in mice, pABOL-formulated saRNA led to variable responses in ferrets. Animals that responded to the vaccine with higher levels of influenza virus-specific neutralizing antibodies were more protected against influenza virus infection. pABOL-formulated saRNA is immunogenic in ferrets, but further optimization of RNA vaccine formulation and constructs is required to increase the quality and quantity of the antibody response to the vaccine.

Activities of muscadine grape skin and quercetin against Helicobacter pylori infection in mice.

AIMS: To explore the preventative potential of muscadine grape skin (MGS) and the single flavonoid, quercetin, as an alternative means for ameliorating Helicobacter pylori infection and/or the H. pylori-induced inflammatory response in mice. METHODS AND RESULTS: The antimicrobial and anti-inflammatory properties of MGS and quercetin, a major phenolic constituent, were evaluated against H. pylori in vitro and in vivo. The antimicrobial activity of quercetin was evaluated against 11 H. pylori strains in vitro with inhibition of all strains at 128-64 µg ml(-1) . In vivo studies showed a moderate reduction in H. pylori counts following treatment with 5 and 10% MGS or quercetin (25 mg kg(-1) body weight) in addition to significantly reduced inflammatory cytokines (TNF-α, IL-1ß and IFN-γ) when compared with untreated mice. CONCLUSIONS: MGS and quercetin did not significantly reduce H. pylori growth in a mouse model. However, these products were effective in regulating the inflammatory response to H. pylori infection. SIGNIFICANCE AND IMPACT OF THE STUDY: Our results suggest that H. pylori infection may be reduced or prevented via the consumption of fruits rich in certain phenolic compounds (e.g. quercetin) such as muscadine grapes.

Range of motion measurements diverge with increasing age for COL5A1 genotypes.

Increased and decreased joint range of motion (ROM) are modifiable risk factors for musculoskeletal soft-tissue injuries. Certain heritable disorders of connective tissue, which have a unifying symptom of joint hypermobility, are caused by mutations within the COL5A1 gene. Furthermore, the COL5A1 BstUI restriction fragment length polymorphism (RFLP) sequence variant is associated with ROM measurements in a mixed injured/uninjured cohort. The association between COL5A1 BstUI RFLP and sit and reach (SR) ROM in an apparently healthy and physically active cohort was investigated. The SR test was performed on 325 white subjects (204 males). Subjects were also genotyped for the BstUI RFLP (C/T) within the 3'-untranslated region of the COL5A1 gene. The COL5A1 BstUI RFLP genotype was associated with SR ROM in older (≥35 years) subjects (TT: 225 ± 96 mm, TC: 245 ± 100 mm, CC: 32 ± 108 mm, N=96, P=0.017). Age and COL5A1 BstUI genotype interacted significantly for SR ROM. Sex and COL5A1 genotype accounted for 22.8% of the variance in SR ROM in the older group. The COL5A1 BstUI RFLP is associated with SR ROM, particularly with increasing age and is an important contributing factor to ROM variation, particularly in older, apparently healthy and physically active individuals.

Presenting features of female collegiate sports-related concussion in South Africa: a descriptive analysis.

Background: Sports-related concussion (SRC) is an injury with important implications, especially in collision and contact sports, and has a high symptom burden. Student athletes face particular psychosocial challenges, especially female students with pre-existing anxiety/depression are at increased risk for SRC, and have a higher symptom burden before and after injury. Objectives: Describing female SRC presenting features at a collegiate campus-based sports medicine service; examining the association of prior concussion history (PCONC) and pre-existing anxiety/depression (PMHDx) with SRC. Methods: A retrospective cohort and statistical analysis (including corrected effect sizes) of Sport Concussion Assessment Tool (versions 3/5) data (Step 1: PCONC and PMHDx history; Step 2: symptom evaluation) of collegiate female athletes with SRC between 2012 and 2018. Results: Forty females with SRC were identified (age 23 ± 3). The five most frequent symptoms were headache (n = 34; 85%), feeling slowed down (n = 33; 83%), pressure in head (n = 33; 83%), don't feel right (n = 32; 80%) and fatigue/low-energy (n = 32; 80%). These five symptoms also had the highest self-rated severity (median (IQR): headache (3 (2-4)), feeling slowed down (3 (1-4)), fatigue/low-energy (3 (1-5)), don't feel right (3 (1-4)) and pressure in head (3 (2-4)). PMHDx (n = 8; 62.9 vs 38.6; p = 0.0192; Hedges' gs = 0.95; large ES), and not PCONC (n = 13; 51.0 vs 39.8; p = 0.2183; Hedges' gs = 0.48; small ES) was associated with increased mean total symptom severity. Conclusion: Headache, feeling slowed down, pressure in head, don't feel right and fatigue/low-energy had the highest symptom burden. Total symptom severity was no different in those with and without PCONC, but significantly higher in those with PMHDx.

Autoregulation of an antibody response via network-induced auto-anti-idiotype.

The antibody response of a single outbred rabbit was studied throughout three rounds of injections with Micrococcus lysodeikticus vaccine over a 31-mo period. The first-round response was characterized by a vigorous anti- micrococcus response and a strong anti-IgG rheumatoid factor response. The second-round response consisted of a triad of interacting molecules: anti- micrococcal antibodies, autoanti-idiotypic antibodies specific for distinct clonotypes of the first-round anti-micrococcal antibodies, and Fc-specific anti-IgG rheumatoid factor. The interacting triple complex was detected because of the formation of an immune complex that became insoluble upon dilution of the serum. Complex formation was inhibited in the presence of saccharide compounds known to be major immunodominant determinants of the micrococcal cell-wall carbohydrate polymer. The same saccharides did not affect the reaction of rheumatoid factor with IgG. Direct-binding radioimmunoassays ruled out mediation of the dilution-precipitation reaction by soluble micrococcal antigens. Specific absorption of rheumatoid factor inhibited the dilution-precipitation reaction. Auto-anti-idiotypic antibodies were specifically purified from second-round sera, directly confirming the presence of these antibodies. Suppressive effects of auto-anti-idiotypic antibodies on distinct antibody clonotypes were shown by gel isoelectric focusing of first-, second-, and third-round sera. Clonotypes expressed in the first round of immunizations were reduced in quantity or absent when auto-anti-idiotypic antibodies were detectable. Greatly enhanced levels or initial synthesis of new clonotypes of anti-micrococcal antibodies were detected during the period of auto-anti-idiotype synthesis. The third-round sera, devoid of detectable auto-anti-idiotype, contained clonotypes characteristic of both first- and second-round antisera. Thus, auto-anti- idiotypic-mediated suppression appeared to be reversible. The data are interpreted as lending strong support for concepts of autoregulation of immune processes in normal outbred animals via an idiotypic network.

Bend propagation in the flagella of migrating human sperm, and its modulation by viscosity.

A pre-requisite for sexual reproduction is successful unification of the male and female gametes; in externally-fertilising echinoderms the male gamete is brought into close proximity to the female gamete through chemotaxis, the associated signalling and flagellar beat changes being elegantly characterised in several species. In the human, sperm traverse a relatively high-viscosity mucus coating the tract surfaces, there being a tantalising possible role for chemotaxis. To understand human sperm migration and guidance, studies must therefore employ similar viscous in vitro environments. High frame rate digital imaging is used for the first time to characterise the flagellar movement of migrating sperm in low and high viscosities. While qualitative features have been reported previously, we show in precise spatial and temporal detail waveform evolution along the flagellum. In low viscosity the flagellum continuously moves out of the focal plane, compromising the measurement of true curvature, nonetheless the presence of torsion can be inferred. In high viscosities curvature can be accurately determined and we show how waves propagate at approximately constant speed. Progressing waves increase in curvature approximately linearly except for a sharper increase over a distance approximately 20-27 microm from the head/midpiece junction. Curvature modulation, likely influenced by the outer dense fibres, creates the characteristic waveforms of high viscosity swimming, with remarkably effective cell progression against greatly increased resistance, even in high viscosity liquids. Assessment of motility in physiological viscosities will be essential in future basic research, studies of chemotaxis and novel diagnostics.

Influence of birth weight on gene regulators of lipid metabolism and utilization in subcutaneous adipose tissue and skeletal muscle of neonatal pigs.

Epidemiological studies suggest that low-birth weight infants show poor neonatal growth and increased susceptibility to metabolic syndrome, in particular, obesity and diabetes. Adipose tissue development is regulated by many genes, including members of the peroxisome proliferator-activated receptor (PPAR) and the fatty acid-binding protein (FABP) families. The aim of this study was to determine the influence of birth weight on key adipose and skeletal muscle tissue regulating genes. Piglets from 11 litters were ranked according to birth weight and 3 from each litter assigned to small, normal, or large-birth weight groups. Tissue samples were collected on day 7 or 14. Plasma metabolite concentrations and the expression of PPARG2, PPARA, FABP3, and FABP4 genes were determined in subcutaneous adipose tissue and skeletal muscle. Adipocyte number and area were determined histologically. Expression of FABP3 and 4 was significantly reduced in small and large, compared with normal, piglets in adipose tissue on day 7 and in skeletal muscle on day 14. On day 7, PPARA and PPARG2 were significantly reduced in adipose tissue from small and large piglets. Adipose tissue from small piglets contained more adipocytes than normal or large piglets. Birth weight had no effect on adipose tissue and skeletal muscle lipid content. Low-birth weight is associated with tissue-specific and time-dependent effects on lipid-regulating genes as well as morphological changes in adipose tissue. It remains to be seen whether these developmental changes alter an individual's susceptibility to metabolic syndrome.

Site-specific maturation of enveloped viruses in L cells treated with cytochalasin B.

Treatment of infected L cells with 10 micrograms/ml cytochalasin B (CB) was found to promote a rapid relocalization of viral glycoproteins on the cell surface. Whereas the vesicular stomatitis virus G protein and the influenza virus hemagglutinin were uniformly distributed on the surface of untreated cells, in CB-treated cells, they were strikingly concentrated at cell extremities in the regions of clustered blebs. Glycoprotein concentration at cell extremities was accompanied by preferential maturation of virus particles from the same sites; both vesicular stomatitis and influenza viruses budded predominantly from the vicinity of clustered blebs. This effect of CB was completely reversible. Removal of CB from the cell growth medium resulted in a return of viral glycoproteins to the uniform distribution characteristic of untreated cells and to uniform virus budding. The results of this study are interpreted in terms of a model that suggests that preferential budding of viruses from the regions of bleb clusters is due to the concentration of viral glycoproteins at these sites.