University of South Carolina Salkehatchie

The relationship between the daily rhythms of locomotor activity and body temperature was studied by telemetry in four nocturnal and four diurnal mammalian species. The results showed that the two rhythms are very closely synchronized, as they 1) ascend past the daily mean at the same time, 2) reach the daily acrophase at the same time, and 3) are best correlated at time lags approaching zero. The rhythms of nocturnal animals crossed the daily mean at the transition between the light and dark phases of the light-dark cycle and reached their acrophases during the dark phase, whereas the rhythms of diurnal animals crossed the daily mean at the transition between the dark and light phases and reached their acrophases during the light phase. Despite the close synchrony of the two rhythms, the results indicate that the temperature rhythm is not a byproduct of the activity rhythm, as body temperature during the active phase of the daily cycle was higher than body temperature during the inactive phase in all species irrespective of the activity level prevailing during each phase.

The division of animals into those that are diurnal (day-active) and those that are nocturnal (night-active) is widely recognized. However, closer examination of the selection of temporal niches by mammalian species reveals the existence of a gradient of diurnality between and within species, wherein “diurnal” and “nocturnal” are merely the opposite ends of a continuum. Evidence against a simple diurnal – nocturnal dichotomy includes the existence of species without any preference for time of day, species with a crepuscular pattern of activity, species containing both diurnal and nocturnal individuals, species containing individuals that spontaneously shift from a nocturnal to a diurnal activity pattern, species showing degrees of diurnality greater or smaller than those of other species, organismal variables exhibiting degrees of diurnality greater or smaller than those of other variables, and species having different temporal patterns under the effects of different environmental variables. Research on the neural processes responsible for temporal niche selection has revealed no fundamental difference between the circadian clocks of diurnal and nocturnal animals, but recent findings suggest that different output pathways from the clock in a given species may operate with different circadian phases, thus providing an explanation for why different body functions in the same individual are subjected to different temporal niche selections.

Rare sugars, referred to as monosaccharides and their derivatives that rarely exist in nature, can be applied in many areas ranging from foodstuffs to pharmaceutical and nutrition industry, or as starting materials for various natural products and drug candidates. Unfortunately, an important factor restricting the utilization of rare sugars is their limited availability, resulting from limited synthetic methods. Nowadays, microbial and enzymatic transformations have become a very powerful tool in this field. This article reviews the biosynthesis and enzymatic production of rare ketohexoses, aldohexoses and sugar alcohols (hexitols), including D-tagatose, D-psicose, D-sorbose, L-tagatose, L-fructose, 1-deoxy-L-fructose, D-allose, L-glucose, L-talose, D-gulose, L-galactose, L-fucose, allitol, D-talitol, and L-sorbitol. New systems and robust catalysts resulting from advancements in genomics and bioengineering are also discussed.

The WaaL-mediated ligation of O-antigen onto the core region of the lipid A-core block is an important step in the lipopolysaccharide (LPS) biosynthetic pathway. Although the LPS biosynthesis has been largely characterized, only a limited amount of in vitro biochemical evidence has been established for the ligation reaction. Such limitations have primarily resulted from the barriers in purifying WaaL homologues and obtaining chemically defined substrates. Accordingly, we describe herein a chemical biology approach that enabled the reconstitution of this ligation reaction. The O-antigen repeating unit (O-unit) of Escherichia coli O86 was first enzymatically assembled via sequential enzymatic glycosylation of a chemically synthesized GalNAc-pyrophosphate-undecaprenyl precursor. Subsequent expression of WaaL through use of a chaperone co-expression system then enabled the demonstration of the in vitro ligation between the synthesized donor (O-unit-pyrophosphate-undecaprenyl) and the isolated lipid A-core acceptor. The previously reported ATP and divalent metal cation dependence were not observed using this system. Further analyses of other donor substrates revealed that WaaL possesses a highly relaxed specificity toward both the lipid moiety and the glycan moiety of the donor. Lastly, three conserved amino acid residues identified by sequence alignment were found essential for the WaaL activity. Taken together, the present work represents an in vitro systematic investigation of the WaaL function using a chemical biology approach, providing a system that could facilitate the elucidation of the mechanism of WaaL-catalyzed ligation reaction. The WaaL-mediated ligation of O-antigen onto the core region of the lipid A-core block is an important step in the lipopolysaccharide (LPS) biosynthetic pathway. Although the LPS biosynthesis has been largely characterized, only a limited amount of in vitro biochemical evidence has been established for the ligation reaction. Such limitations have primarily resulted from the barriers in purifying WaaL homologues and obtaining chemically defined substrates. Accordingly, we describe herein a chemical biology approach that enabled the reconstitution of this ligation reaction. The O-antigen repeating unit (O-unit) of Escherichia coli O86 was first enzymatically assembled via sequential enzymatic glycosylation of a chemically synthesized GalNAc-pyrophosphate-undecaprenyl precursor. Subsequent expression of WaaL through use of a chaperone co-expression system then enabled the demonstration of the in vitro ligation between the synthesized donor (O-unit-pyrophosphate-undecaprenyl) and the isolated lipid A-core acceptor. The previously reported ATP and divalent metal cation dependence were not observed using this system. Further analyses of other donor substrates revealed that WaaL possesses a highly relaxed specificity toward both the lipid moiety and the glycan moiety of the donor. Lastly, three conserved amino acid residues identified by sequence alignment were found essential for the WaaL activity. Taken together, the present work represents an in vitro systematic investigation of the WaaL function using a chemical biology approach, providing a system that could facilitate the elucidation of the mechanism of WaaL-catalyzed ligation reaction.

This article reviews the literature on the circadian and estrous rhythms of body temperature in farm animals. Although most research in this area has lacked the methodological sophistication of research conducted on laboratory animals, the experimental results are consistent with the general principles of thermal chronobiology derived from laboratory studies and, at the same time, provide specific information about the peculiarities of livestock species. Detailed knowledge of the normal parameters of the body temperature rhythms is important for the advancement of diagnostic procedures in veterinary medicine and for the optimization of farm yield in the dairy and meat industry.

Abstract Thin layer chromatography (TLC) is a quick, sensitive, and inexpensive technique used to determine the number of components in a mixture, verify the identity and purity of a compound, monitor the progress of a reaction, determine the solvent composition for preparative separations, and analyze the fractions obtained from column chromatography. This unit is mainly aimed at novice experimenters, describing in detail the strategies and principal steps for performing a TLC experiment, with illustrations of the relevant instruments, as well as approaches for obtaining and understanding results. Valuable practical tips and troubleshooting solutions are also provided throughout the unit. Curr. Protoc. Essential Lab. Tech . 8:6.3.1‐6.3.18. © 2014 by John Wiley & Sons, Inc.

Prolonged food deprivation is known to cause a fall in the core body temperature of homeotherms. In various species of small birds and mammals (body mass up to 2-3 kg), it has been shown that starvation-induced hypothermia is modulated by the circadian system, in the sense that hypothermia is observed primarily during the inactive phase of the daily activity cycle (i.e., during the night for diurnal animals and during the day for nocturnal animals), whereas relatively normal temperatures are recorded during the active phase. To investigate whether this modulation occurs also in larger animals, we investigated the effects of 4 d food deprivation on the body temperature rhythm of goats and sheep (body mass 30-40 kg). In goats, the body temperature rhythm was found to have a mean level of 39.0 degrees C with a mean daily range of excursion of 0.42 degrees C. The daily oscillation in body temperature persisted during the first day of fasting, but the rhythm was drastically damped, if not eliminated, over the next 3 d as body temperature descended from the baseline level of 39.0 to 38.2 degrees C. In sheep, the rhythm was found to have a mean level of 39.3 degrees C with a mean daily range of excursion of 0.34 degrees C. The daily oscillation in body temperature persisted through the 4 d of food deprivation, even though the mean level of body temperature gradually fell. Temperature fell more during the third and fourth nights than during the third and fourth days. Thus, circadian modulation of starvation-induced hypothermia was observed in sheep but not in goats.

Life history theory (LHT) predicts that individuals vary in their sexual, reproductive, parental, familial, and social behavior according to the physical and social challenges imposed upon them throughout development. LHT provides a framework for understanding why non-monogamy may be the target of significant moral condemnation: individuals who habitually form multiple romantic or sexual partnerships may pursue riskier, more competitive interpersonal strategies that strain social cooperation. We compared several indices of life history (i.e., the Mini-K, the High-K Strategy Scale, pubertal timing, sociosexuality, disease avoidance, and risk-taking) between individuals practicing monogamous and consensually non-monogamous (CNM) romantic relationships. Across several measures, CNM individuals reported a faster life history strategy than monogamous individuals, and women in CNM relationships reported earlier pubertal development. CNM individuals also reported more social and ethical risk-taking, less aversion to germs, and greater interest in short-term mating (and less interest in long-term mating) than monogamous individuals. From these data, we discuss a model to explain how moral stigma toward non-monogamy evolved and how these attitudes may be mismatched to the modern environment. Specifically, we argue that the culture of sexual ethics that pervades contemporary CNM communities (e.g., polyamory, swinging) may attenuate risky interpersonal behaviors (e.g., violent intrasexual competition, retributive jealousy, partner/child abandonment, disease transmission) that are relatively more common among those who pursue multi-partner mating.

Daily or circadian rhythmicity in physiological processes has been described in a large number of species of birds and mammals. However, in dogs, most studies have either failed to detect rhythmicity or have found that rhythmicity reflects merely an acute exogenous effect of feeding rather than an autonomous rhythmic process. In the present study, we investigated the rhythmicity of body temperature, blood pressure, and heart rate in dogs fed daily as well as in dogs deprived of food for 60 h. Our results document clear rhythmicity in all three parameters and demonstrate that the rhythmicity is independent of the feeding schedule. The failure of various previous investigations to document daily rhythmicity in dogs is probably due to lack of experimental rigour rather than to weakness of daily rhythmicity in dogs.

Recruitment of antibodies in human immune systems for targeted destruction of tumor cells has emerged as an exciting area of research due to its low occurrence of side effects, high efficacy, and high specificity. The presence of large amounts of anticarbohydrate natural antibodies in human sera has prompted research efforts to utilize carbohydrate epitopes for immune recruitment. Here, we have developed a general strategy for specific targeted destruction of tumor cells based on rhamnose-functionalized liposomes. Tumor cells artificially decorated with rhamnose epitopes were subjected to complement-mediated cytotoxicity in vitro and showed delayed tumor growth in vivo. This study highlights the therapeutic potential for activation of endogenous immune response through cell-surface glycan engineering.

BACKGROUND: Nycthemeral (daily) oscillation has been documented in a variety of physiological and behavioral processes. The present study was carried out to evaluate the existence of a nycthemeral rhythm of human sexual behavior and to identify environmental factors responsible for the rhythmic pattern. METHODS: Non-traditional university students (ages 18 to 51 years) recorded the times of day when they went to sleep, when they woke up, and when they had sex for 3 consecutive weeks. They also answered a questionnaire designed to identify the causes of their selection of time for sex. RESULTS: The majority of sexual encounters took place at bedtime (11 pm to 1 am). The most common explanations for this temporal pattern were the rigidity of the professional work schedule and family obligations and the availability of the partner, which reduced the opportunity for sexual encounters at other times of the day. CONCLUSION: Most sexual encounters take place around bedtime. Although the presence of an endogenous component responsible for this temporal pattern cannot be excluded, the evidence indicates strong environmental forcing, particularly from the work/family schedule of the individuals and from partner availability.

Metabolic heat production (calculated from oxygen consumption), dry heat loss (measured in a calorimeter) and body temperature (measured by telemetry) were recorded simultaneously at 6 min intervals over five consecutive days in rats maintained in constant darkness. Robust circadian rhythmicity (confirmed by chi square periodogram analysis) was observed in all three variables. The rhythm of heat production was phase-advanced by about half an hour in relation to the body temperature rhythm, whereas the rhythm of heat loss was phase-delayed by about half an hour. The balance of heat production and heat loss exhibited a daily oscillation 180 deg out of phase with the oscillation in body temperature. Computations indicated that the amount of heat associated with the generation of the body temperature rhythm (1.6 kJ) corresponds to less than 1 % of the total daily energy budget (172 kJ) in this species. Because of the small magnitude of the fraction of heat balance associated with the body temperature rhythm, it is likely that the daily oscillation in heat balance has a very slow effect on body temperature, thus accounting for the 180 deg phase difference between the rhythms of heat balance and body temperature.

Recent work demonstrates the methodological rigor of a type of data-driven analysis (i.e., conjoint analysis; CA), which accounts for the relative contribution of different facial morphological cues to interpersonal perceptions of romantic partner quality. This study extends this literature by using a conjoint face ranking task to predict the relative contribution of five sexually dimorphic facial shape features (jawbone & cheekbone prominence, eyebrow thickness, eye size, face length) to participants’ (N = 922) perceptions of facial attractiveness and sex-typicality (i.e., masculinity/femininity). For overall partner attractiveness, eyebrow thickness and jawbone prominence were relatively more salient than cheekbone prominence and eye size. Interestingly, masculinized (i.e., thicker) eyebrows were marginally more attractive for female than male faces, particularly within a long-term mating context. Masculinized jawbone prominence was more attractive for male than female faces, and feminized jawbone prominence was more attractive for female than male faces. For perceptions of masculinity, eyebrow thickness, jawbone prominence, and facial height were relatively more salient than cheekbone prominence and eye size, although facial height was more important for female than male faces, and jawbone prominence was marginally more important for male than female faces. These findings highlight the prominence of eyebrows, the jawline, and facial height during perception of facial attractiveness and masculinity – though it should be noted that many of these differences were small to moderate in effect size. Findings are interpreted in the context of prior research, and future directions for studying why these facial traits exhibit superior signaling capacity are discussed.

Modification of an enveloped measles virus was achieved by metabolic incorporation of azido sugars in host cells through the protein glycosylation process. Based on this, the resulting measles virus particles could be modified with azido groups on the surface glycoproteins, which could be further labeled with fluorescence dyes using a strain-promoted azide-alkyne cycloaddition reaction. We envision this metabolic labeling approach to be applicable to a wide variety of enveloped viruses, allowing the facile conjugation and surface modification.

Almost all Streptococcus pneumoniae (pneumococcus) capsule serotypes employ the Wzy-dependent pathway for their capsular polysaccharide (CPS) biosynthesis. The assembly of the CPS repeating unit (RU) is the first committed step in this pathway. The wciN gene was predicted to encode a galactosyltransferase involved in the RU assembly of pneumococcus type 6B CPS. Herein, we provide the unambiguous in vitro biochemical evidence that wciN encodes an α-1,3-galactosyltransferase catalyzing the transfer of galactosyl from UDP-Gal onto the Glcα-pyrophosphate-lipid (Glcα-PP-lipid) acceptor to form Galα(1-3)Glcα-PP-lipid. A chemically synthesized acceptor (Glcα-PP-O(CH(2))(10)CH(3)) was used to characterize the WciN activity. The disaccharide product, i.e., Galα(1-3)Glcα-PP-O(CH(2))(10)CH(3), was characterized by mass and NMR spectroscopy. Substrate specificity study indicated that the acceptor structural region composed of pyrophosphate and lipid moieties may play an important role in the enzyme-acceptor recognition. Furthermore, divalent metal cations were found indispensable to the WciN activity, suggesting that this glycosyltransferase (GT) belongs to the GT-A superfamily. By analyzing the activities of six WciN mutants, a DXD motif involved in the coordination of a divalent metal cation was identified. This work provides a chemical biology approach to characterize the activities of pneumococcal CPS GTs in vitro and will help to better understand the pneumococcal CPS biosynthetic pathway.

Glycosylation is one of the most important reactions in nature as it results in the formation of glycoconjugates with diverse biological functions. Sugar nucleotides serve as the natural donor molecules for the biosynthesis of such glycoconjugates and other carbohydrates. Furthermore, these donor molecules are also indispensable building blocks for the enzymatic synthesis of carbohydrates in vitro using Leloir-type glycosyltransferases. Given such importance, the biosynthetic pathways of sugar nucleotides have been exploited, enabling the development of both chemical and enzymatic approaches to produce these molecules. A survey of recent progress in enzymatic synthesis of common mammalian sugar nucleotides as well as their derivatives is thus presented. As a popular strategy, conjugation of sugar nucleotide synthesis with glycosyltransfer reactions and in vivo production of sugar nucleotides are also included.

Choice procedures have indicated that the relative reinforcing effectiveness of opioid drugs increases during opioid withdrawal. The demand curve, an absolute measure of reinforcer value, has not been applied to this question. The present study assessed whether mild morphine withdrawal would increase demand for or choice of remifentanil or cocaine. Four rhesus monkeys chose between remifentanil and cocaine during daily sessions. Demand curves for both drugs were subsequently obtained. The effects of daily injections of 3.2 mg/kg morphine on both choice and demand for these drugs was assayed 3 and 20.5 hr after each morphine injection, and then during a postmorphine period. Three hours following morphine injections, choice of remifentanil over cocaine decreased and demand for remifentanil--but not cocaine--became more elastic. During morphine withdrawal (20.5 hr postinjection), choice of remifentanil increased and remifentanil demand became more inelastic in 3 of 4 monkeys. Cocaine demand also became more inelastic during this period. Four to five weeks following the morphine regimen, demand for both drugs was more inelastic relative to the initial determination. The results suggest that both the relative and absolute reinforcing effectiveness of remifentanil decreased following morphine administration and increased during morphine withdrawal. The absolute reinforcing effectiveness of cocaine also increased during morphine withdrawal. In addition, extended exposure to drug self-administration and/or exposure to the morphine regimen produced long-term increases in demand for both drugs.

Circadian rhythms in mammals are generated by an endogenous pacemaker but are modulated by environmental cycles, principally the alternation of light and darkness. Although much is known about nonparametric effects of light on the circadian system, little is known about other effects of photic stimulation. In the present study, which consists of a series of five experiments in mice, various manipulations of photic stimulation were used to dissect the mechanisms responsible for a variation in the magnitude of light-induced phase-shifts that results from prolonged exposure to darkness. The results confirmed previous observations that prolonged exposure to darkness causes an increase in the magnitude of phase shifts (both phase advances and phase delays) evoked by discrete light pulses. The results also indicated that the increase in responsiveness results from the lack of exposure to light per se and not from collateral effects of exposure to constant darkness such as the lack of previous entrainment. The lack of exposure to light causes the circadian system to undergo a process of dark adaptation similar to dark adaptation in the visual system but with a much slower temporal course. The results suggest that circadian dark adaptation may take place at the retinal level, but it is not clear whether it involves a change in the sensitivity or maximal responsiveness of the system.

Animals, plants, and microorganisms exhibit numerous biological rhythms that are generated by numerous biological clocks. This article summarizes experimental data pertinent to the often-ignored issue of integration of multiple rhythms. Five contexts of integration are discussed: (i) integration of circadian rhythms of multiple processes within an individual organism, (ii) integration of biological rhythms operating in different time scales (such as tidal, daily, and seasonal), (iii) integration of rhythms across multiple species, (iv) integration of rhythms of different members of a species, and (v) integration of rhythmicity and physiological homeostasis. Understanding of these multiple rhythmic interactions is an important first step in the eventual thorough understanding of how organisms arrange their vital functions temporally within and without their bodies.

Four experiments examined whether scene processing is facilitated by layout representation, including layout that was not perceived but could be predicted based on a previous partial view (boundary extension). In a priming paradigm (after Sanocki, 2003), participants judged objects' distances in photographs. In Experiment 1, full scenes (target), partial scenes, and two control primes were used. Partial scenes excluded the target objects' locations, but these areas could be predicted. Full and partial scenes produced equal performance facilitation. In Experiment 2, task-irrelevant partial scene primes were also tested. These primes did not facilitate performance (i.e. simple scene previews did not help). Experiment 3 showed that a partial prime's utility depended on the area of the scene that would be tested; the task-irrelevant primes used in Experiment 2 were useful for other distance judgments. Experiment 4 showed that partial scene facilitation is not limited to the area immediately surrounding the prime. The study demonstrated that perceived and mentally extrapolated layouts are equally effective.