The La Crosse virus (LACV) is an emerging pathogen in the Appalachian region of the United States. The virus maintains a complex natural cycle through horizontal transmission with sciurid rodents and Aedes mosquitoes in Virginia. Transovarial transmission also occurs in this host-parasite system and has evolved for the virus to persist through winter. The virus perpetuates in diapause induced embryos and infects naive rodents the following spring. As global temperatures rise, it is imperative we evaluate how the virus and its vectors overwinter. We conducted experiments to evaluate and determine the diapause induction, or prediapause stage, in Aedes japonicus japonicus, and the ecophysiology and low temperature biology of how LACV affects Aedes triseriatus and Aedes albopictus embryos at low temperatures. We found that the prediapause stage of Ae. j. japonicus is the maternal stage, the developing adult female that lays diapause eggs. This more closely resembles Ae. albopictus and not Ae. triseriatus. As measured in the field and laboratory, LACV has a clear negative effect on the ability of Ae. triseriatus and Ae. albopictus to survive the winter. There was no major effect of LACV infection on the ability of these two species to enter diapause or their critical photoperiods, but there was a significant negative effect of LACV infection on survivorship of embryos that were placed in their natural habitat and in their susceptibility to low temperatures. LACV infection had a more significant negative effect on Ae. albopictus than on Ae. triseriatus and suggests that Ae. albopictus is a subordinate vector relative to Ae. triseriatus in the maintenance of the virus over the winter season. Our findings highlight the need for the increased surveillance of LACV as temperatures continue to rise due to climate change. / PHD / In Virginia, mosquitoes may transmit the La Crosse virus (LACV) that can cause swelling of the brain in humans. This virus infects mosquitoes which is then transmitted to chipmunks. When a mosquito bites an infected chipmunk and then bites a human, the virus be transmitted to the human. Adult female mosquitoes can also pass the virus on to their developing offspring, which is the way it is maintained throughout the winter. Certain infected mosquitoes will spend the winter as eggs and the mosquitoes that hatch carry the virus and can infect chipmunks the following spring. The experiments conducted here looked at how one mosquito that can spread the LACV begins the process to survive the winter. We also did experiments to look at how the virus affects two other mosquito’s ability to begin the same process and then if they can survive the winter and cold temperatures while infected. We found that the Asian Bush Mosquito enters diapause in a different way than we suspected by the female mosquito sensing shorter days at the end of the summer; at this point she will then lay eggs that survive the winter. We discovered that viral infection will hurt the chances of the Asian Tiger Mosquito and Eastern Tree-hole Mosquito to survive the winter. We also found that virus-infected mosquitoes cannot survive temperatures as lower than those that are not infected. This means that the risk of the virus to humans can be greater as temperatures rise due to global warming.

Yes / Wnt signalling and its downstream effectors are well known for their roles in embryogenesis and tumourigenesis, including the regulation of cell proliferation, survival and differentiation. In the nervous system, Wnt signalling has been described mainly during embryonic development, although accumulating evidence suggests that it also plays a major role in adult brain morphogenesis and function. Studies have predominantly concentrated on memory formation in the hippocampus, although recent data indicate that Wnt signalling is also critical for neuroendocrine control of the developed hypothalamus, a brain centre that is key in energy balance regulation and whose dysfunction is implicated in metabolic disorders such as type 2 diabetes and obesity. Based on scattered findings that report the presence of Wnt molecules in the tanycytes and ependymal cells lining the third ventricle and arcuate nucleus neurones of the hypothalamus, their potential importance in key regions of food intake and body weight regulation has been investigated in recent studies. The present review brings together current knowledge on Wnt signalling in the hypothalamus of adult animals and discusses the evidence suggesting a key role for members of the Wnt signalling family in glucose and energy balance regulation in the hypothalamus in diet-induced and genetically obese (leptin deficient) mice. Aspects of Wnt signalling in seasonal (photoperiod sensitive) rodents are also highlighted, given the recent evidence indicating that the Wnt pathway in the hypothalamus is not only regulated by diet and leptin, but also by photoperiod in seasonal animals, which is connected to natural adaptive changes in food intake and body weight. Thus, Wnt signalling appears to be critical as a modulator for normal functioning of the physiological state in the healthy adult brain, and is also crucial for normal glucose and energy homeostasis where its dysregulation can lead to a range of metabolic disorders.

Yes / Seasonal or photoperiodically sensitive animals respond to altered day length with changes in physiology (growth, food intake and reproductive status) and behaviour to adapt to predictable yearly changes in the climate. Typically, different species of hamsters, voles and sheep are the most studied animal models of photoperiodism. Although laboratory rats are generally considered nonphotoperiodic, one rat strain, the inbred Fischer 344 (F344) rat, has been shown to be sensitive to the length of daylight exposure by changing its physiological phenotype and reproductive status according to the season. The present study aimed to better understand the nature of the photoperiodic response in the F344 rat. We examined the effects of five different photoperiods on the physiological and neuroendocrine responses. Young male F344 rats were held under light schedules ranging from 8 h of light/day to 16 h of light/day, and then body weight, including fat and lean mass, food intake, testes weights and hypothalamic gene expression were compared. We found that rats held under photoperiods of ≥ 12 h of light/day showed increased growth and food intake relative to rats held under photoperiods of ≤ 10 h of light/day. Magnetic resonance imaging analysis confirmed that these changes were mainly the result of a change in lean body mass. The same pattern was evident for reproductive status, with higher paired testes weight in photoperiods of ≥ 12 h of light/day. Accompanying the changes in physiological status were major changes in hypothalamic thyroid hormone (Dio2 and Dio3), retinoic acid (Crabp1 and Stra6) and Wnt/b-Catenin signalling genes (sFrp2 and Mfrp). Our data demonstrate that a photoperiod schedule of 12 h of light/day is interpreted as a stimulatory photoperiod by the neuroendocrine system of young male F344 rats.

This thesis is aimed at improving techniques for induced maturation and artificial fertilization of Morone. Chapter 1 is a study of hybrid bass (n = 73) exposed to 6- or 9-month photothermal cycles which were formed by excising summer or summer and fall photothermal conditions from an annual regime. Shortened cycles abbreviated the interval between spawning and recrudescence, and advanced maturation by five and four months, respectively. All females developed functionally mature oocytes and ovulated after hormone injection. Maximum testicular sizes were similar and occurred after similar periods (153-199 d). Milt was produced in most (> 90%) males. Some milt characteristics differed among males in the three cycles, but fertility was similar. Findings suggest that excised cycles can advance maturation in hybrid bass, permitting off-season spawning. In Chapter 2, effects of stripping frequency (3 times in 7 days) on semen quality was determined by measuring concentration, motility, osmolality, pH and sugars of milt. Male and female effects on fertility variation were measured by crossing all males and females. Sperm concentration was estimated by spermatocrit, ultraviolet and fluorometric absorbance. Motility (58 sec) and milt pH (8.44) were lowest (p < 0.05) after the third stripping. Concentration (1.76 x 10⁹ cells mL⁻¹) and osmolality also decreased with stripping frequency, but inconsistently among males. Fertility was highest during the second stripping and was correlated with milt pH (r = 0.762). Fertility variation was caused by females (p = 0.001). Results provide the first characterization of Morone semen quality. They suggest that frequent stripping alters milt parameters, that females account for most fertility variation, and that sperm concentration can be estimated reliably by spermatocrit. / Master of Science

Yes / The photoperiod is the main environmental cue that drives seasonal adaptive responses in reproduction, behavior, and metabolism in seasonal animals. Increasing evidence suggests that (poly)phenols contained in fruits can also modulate seasonal rhythms. (Poly)phenol-rich diets are associated with an improvement in cognitive function and neuroprotection due to their anti-inflammatory and antioxidative properties. However, it is unknown whether cherries affect neuroprotection in a photoperiod-dependent manner. To test this, F344 rats were exposed to L6 (6 h light/day), L12 (12 h light/day) and L18 (18 h light/day) photoperiods and fed a standard chow diet supplemented with either a control, lyophilized cherry 1 or cherry 2 with distinctive phenolic hallmarks. Physiological parameters (body weight, eating pattern index (EPI), testosterone, T4/T3) and hypothalamic key genes (Dio2, Dio3, Raldh1 and Ghrh) were strongly regulated by the photoperiod and/or fruit consumption. Importantly, we show for the first time that neurotrophs (Bdnf, Sod1 and Gpx1) in the hippocampus are also regulated by the photoperiod. Furthermore, the consumption of cherry 2, which was richer in total flavonols, but not cherry 1, which was richer in total anthocyanins and flavanols, enhanced neuroprotection in the hippocampus. Our results show that the seasonal consumption of cherry with a specific phenolic composition plays an important role in the hippocampal activation of neuroprotection in a photoperiod-dependent manner. / This work was supported by grant number PID2020-113739RB-I00 funded by MCIN/AEI/10.13039/501100011033 and by Pect-Nutrisalt funded by the European Regional Development Fund of the European Commission through the Operative Program Erdf of Catalonia 2014–2020. The authors thank the British Society for Neuroendocrinology (BSN) for providing a research visit Grant to F.M (Grant number: BSN-2022-1452). F.M. is the recipient of a predoctoral fellowship from Universitat Rovira i Virgili—Martí i Franquès (Grant number: 2019PMF-PIPF-19).

The Atlantic salmon (Salmo salar) lifecycle is punctuated by distinct ontogenic stages which are routinely manipulated commercially by photoperiod regimes to enable year-round production. As such, light plays a critical role throughout the production cycle, however, it remains poorly characterised and light spectrum and intensity have not been defined optimally yet. This thesis was therefore set out to test the effects of narrow bandwidth light (Blue-&lambda;(max) 444 nm, Green-&lambda;(max) 523 nm, Red-&lambda;(max) 632 nm and White) and intensity in freshwater (FW). Fry-parr development, out-of-season smoltification and ocular and vertebral health were examined as was the long-term effects of FW light regimes on seawater (SW) growth and muscle structure. In addition, the impact of photoperiod regimes on out-of-season smolts following transfer to SW was investigated. &NewLine; Major findings from the trials conducted show that light spectrum and intensity influence parr development with lower intensities performing better than higher intensities. Both the initiation and duration of smoltification was impacted by spectrum. Importantly, this doctoral work showed that daily changes in light intensity, from low during the scotophase to high during the photophase applied for the duration of a standard out-of-season smoltification regime was capable of providing a sufficient cue for the induction of smoltification. Historic FW light exposure impacted SW performance and post-transfer SW photoperiod had significant impact upon growth and maturation development. Results based on changes to the gonadosomatic index provide important guidance for suitable post-transfer photoperiods for smolt transferred to SW around the winter solstice. Importantly, from the parameters tested, exposure to different spectrum or light intensities did not adversely affect vertebral or ocular health. &NewLine; This thesis did not only focus on the physiological effects of light but also aimed to characterise better the pathways involved in light perception and integration. To do so, the neural response to both broad spectrum white light, darkness and Red and Blue light was investigated through deep brain insitu-hybridisation and high throughput sequencing (NGS) of the pituitary gland. Results showed substantial spectral and light/dark changes in the both the deep brain and pituitary transcriptome. Overall, this research provides both scientifically interesting and commercially relevant guidance for the optimisation of lighting systems for use in captive salmon aquaculture. Major findings from the trials conducted show that light spectrum and intensity influence parr development with lower intensities performing better than higher intensities. Both the initiation and duration of smoltification was impacted by spectrum. Importantly, this doctoral work showed that daily changes in light intensity, from low during the scotophase to high during the photophase applied for the duration of a standard out-of-season smoltification regime was capable of providing a sufficient cue for the induction of smoltification. Historic FW light exposure impacted SW performance and post-transfer SW photoperiod had significant impact upon growth and maturation development. Results based on changes to the gonadosomatic index provide important guidance for suitable post-transfer photoperiods for smolt transferred to SW around the winter solstice. Importantly, from the parameters tested, exposure to different spectrum or light intensities did not adversely affect vertebral or ocular health. This thesis did not only focus on the physiological effects of light but also aimed to characterise better the pathways involved in light perception and integration. To do so, the neural response to both broad spectrum white light, darkness and Red and Blue light was investigated through deep brain insitu-hybridisation and high throughput sequencing (NGS) of the pituitary gland. Results showed substantial spectral and light/ dark changes in the both the deep brain and pituitary transcriptome. Overall, this research provides both scientifically interesting and commercially relevant guidance for the optimisation of lighting systems for use in captive salmon aquaculture.

Cette thèse a déterminé les rôles respectifs de la photopériode et de la température lors des différentes et successives étapes du cycle de reproduction (induction du cycle, vernalisation, ponte) chez la perche commune Perca fluviatilis femelle. La photopériode est le facteur environnemental principal qui synchronise l’induction du cycle de reproduction chez la perche commune, la température joue uniquement un rôle modulateur. Une baisse importante de la durée de la photophase de 4-8 heures est recommandée. Le maintien d'une photopériode constante basée sur une photophase longue et constante (17L : 7D) inhibe l’induction, alors que le maintien d’une température élevée et constante (22-23°C) ne le permet pas. Pour la phase de vernalisation, une photopériode de type jour court (8L : 16D) est nécessaire. Concernant les effets de la température, une forte et progressive baisse de la température (de 22 à 6°C sur 16 semaines) est recommandée pour assurer un développement gonadique complet (ovocytes aux stades de vitellogenèse avancée en fin de phase d’induction et de la maturation finale avant la période de ponte). Des baisses de température plus modérées (de 22 à 14-18°C) altèrent la reproduction, notamment pendant la phase de vernalisation. L’augmentation finale de la température après la vernalisation est le facteur principal de synchronisation de la ponte. Cette étude a permis la mise au point d’un protocole photo-thermopériodique fiable garantissant des taux d’induction et de ponte très élevés, proches de 100%, chez les femelles / This PhD thesis has determined the respective roles of photoperiod and temperature at the different and successive steps of the reproductive cycle (induction of the cycle, wintering period, spawning) in female Eurasian perch Perca fluviatilis. Photoperiod is the main environmental factor which synchronizes the onset of the reproduction cycle in Eurasian perch female, temperature plays only a modulating role. A high photoperiod decrease of 4 or 8 hours is recommended. The maintenance of constant photoperiod based on a long photophase (17L: 7D) delays the onset of the reproductive cycle, whereas the maintenance of a warm and constant temperature (22-23°C) does not delay it. For the wintering period, a photoperiod with a short daylight period (8L : 16D) is required. Concerning the effect of temperature variations, a high and progressive temperature decrease (from 22 to 6°C over 16 weeks) is recommended to ensure a complete ovarian development (all oocytes achieved the advanced vitellogenesis stage at the end of the induction phase and and final maturation stage just before spawning). Slight temperature decreases (from 22 to 14-18°C) alter the reproduction, especially during the chilling period (wintering period). The final increase of temperature (up to 14°C) after the wintering period is the main factor for spawning synchronization. This study allowed the development of a reliable photo-thermal protocol for out-of-season spawning with very high rates (close to 100%) of female response and spawning

Doctor of Philosophy / Department of Biological and Agricultural Engineering / Yong Cheng Shi / Donghai Wang / Cellulosic ethanol made from low cost lignocellulosic biomass has been considered as new generation transportation fuel with economic and environmental advantages. Photoperiod-sensitive (PS) sorghum, because of its high biomass yield (2.6 kg dry mass/m2), about 18% of soluble sugar in dry mass, and drought tolerance, is a promising biomass for ethanol production. The overall goals of this study are to develop an efficient approach to convert PS sorghum to ethanol and to understand the structural characteristics of biomass. For increasing the efficiency of biomass conversion, an integrated method, using diluted sulfuric acid pretreatment, has been developed to utilize both the structural polysaccharide (cellulose) and the soluble sugar (sucrose, glucose, and fructose) for fermentation. Response surface methodology was employed to optimize the pretreatment condition for maximizing the cellulose-glucose conversion. Simultaneous enzymatic hydrolysis and yeast fermentation was used for ethanol production. The effects of the buffer concentration, the inoculation dosage and time, and the fermentation temperature were investigated for maximizing ethanol yield. A total conversion efficiency of 77.2% and an ethanol concentration of 2.3% (v/v) were obtained after 72 h fermentation. About 210 kg (~266 Liters) ethanol could be produced from one ton dry mass of PS sorghum under the optimized condition. The structural features of the PS sorghum were studied using techniques including scanning electron microscopy and X-ray diffraction/scattering. Biomass at different botanic locations was investigated. Wide-angle X-ray diffraction (WAXD) study showed that the PS sorghum rind had oriented crystal peaks and the highest degree of crystallinity, whereas the crystalline structures of the inner pith and leaf were less ordered. The results from WAXD suggested that crystalline cellulose was melted at 120 °C before its significant degradation. Both the cellulose crystallinity and the crystal size at the dimension lateral to fiber direction increased as the temperature increased from 120 to 160 °C. The efficiency of enzymatic hydrolysis increased because the protective structure was damaged and most hemicellulose was removed, resulting in the increase in accessible area as suggested by small-angle X-ray scattering result of the increased length of microvoids. The results from WAXD also suggested a simultaneous hydrolysis and crystallization of cellulose by acid.

The locomotor activity of the reindeer is separated into a diurnal and a nocturnal phase which, in turn, consists of a  number of short-term activity bursts. The onset and termination  of diurnal and nocturnal activity are largely in synchrony  with sunrise and sunset. Since the diurnal phase is  longer, total activity is dependent on the photoperiod. Total  activity as well as the number of activity bursts is greater  in Jùne with continuous daylight than in December with 6  hours daylight. In winter, reindeer spent less time feeding  but more time ruminating and resting *than in summer. Synchronization  between individuals was also greatest in winter. It  is concluded that the described changes in the activity  pattern are due to an endogenous component and that this component  further controls food consumption and energy balance  of the reindeer.  Seasonal variations in behavioural patterns are described.  Several specific rutting behavioürs, sexual and agonostic,  emerge in the male during the prerut and persist until after  the rut. The preorbital gland is enlarged and secretory activity  is evident. The rut is cha'tabterized by the sudden appearance  of an odour in the breath of mature males followed a few  later by a strong odour in the urine. These odours persist for  a short time during the most intense period of rut. The amount  of androgen rizes sharply and reaches peak concentrations in  late September - early October, decreasing thereafter. The  described behavioural cues occur with a certain constancy in  time in concecutive seasons.  A quantification of the amounts of secretory epithelia in preorbital,  interdigital, caudal and tarsal glands reveals that  only the preorbital gland is subjected to any seasonal and  sexual variation. The apocrine epithelium in this gland is  most developed in mature males during the rutting season and  seems to be dependent upon the presence of an elevated androgen  concentration. The tarsal gland is the least developed  gland while the interdigital and caudal glands are more welldeveloped  and structurally complex. Scattered apocrine glands  are only developed on the legs, the ventral body, oral angle  and in the rump patch. / digitalisering@umu

Orientador: Edivaldo Antonio Garcia / Resumo: Com o objetivo de atualizar as informações relacionadas ao fornecimento de luz para as poedeiras comerciais modernas visando racionalizar o uso da energia elétrica nos sistemas de produção de ovos com manutenção ou melhoria do desempenho produtivo e qualidade dos ovos, foram realizados três experimentos. Em cada experimento foram utilizadas 480 aves da linhagem Lohmann LSL® distribuídas em delineamento em blocos casualizados com quatro tratamentos e seis repetições de 20 aves cada. O experimento I foi realizado para avaliação do efeito do comprimento do fotoperíodo sendo: fotoperíodo 1 - 14 horas de luz e 10 horas de escuro (14L:10E); fotoperíodo 2 – 15 horas de luz e 9 horas de escuro (15L:9E); fotoperíodo 3 – 16 horas de luz e 8 horas de escuro (16L:8E); fotoperíodo 4 – 17 horas de luz e 7 horas de escuro (17L:7E). No experimento II foram testadas quatro iluminâncias: T1 – 5 lux; T2 – 10 lux; T3 – 15 lux; T4 – 20 lux. O fotoperíodo adotado foi o de 14L:10E que proporcionou o melhor resultado no experimento I. O experimento III foi realizado para avaliação de quatro programas de luz: contínuo (controle) – consistiu de um fotoperído único; intermitente 1 – consistiu no fornecimento de 1 hora de luz, uma hora antes do início fotoperíodo natural (manhã); intermitente 2 – consistiu no fornecimento de 30 minutos de luz, uma hora antes do início do fotoperiodo natural; intermitente 3 – consistiu no fornecimento de 15 minutos de luz, uma hora antes do início do fotoperíodo natural.... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor