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Item Global assessment of chemical quality of drinking water: The case of trihalomethanes(Elsevier Ltd, 15/02/2023) Villanueva CM; Evlampidou I; Ibrahim F; Donat-Vargas C; Valentin A; Tugulea A-M; Echigo S; Jovanovic D; Lebedev AT; Lemus-Pérez M; Rodriguez-Susa M; Luzati A; de Cássia Dos Santos Nery T; Pastén PA; Quiñones M; Regli S; Weisman R; Dong S; Ha M; Phattarapattamawong S; Manasfi T; Shaibu-Imodagbe EM; Eng A; Janák K; Rush SC; Reckhow D; Krasner SW; Vineis P; Richardson SD; Kogevinas MBACKGROUND: Trihalomethanes (THM), a major class of disinfection by-products, are widespread and are associated with adverse health effects. We conducted a global evaluation of current THM regulations and concentrations in drinking water. METHODS: We included 120 countries (∼7000 million inhabitants in 2016), representing 94% of the world population. We searched for country regulations and THM routine monitoring data using a questionnaire addressed to referent contacts. Scientific and gray literature was reviewed where contacts were not identified or declined participation. We obtained or estimated annual average THM concentrations, weighted to the population served when possible. RESULTS: Drinking water regulations were ascertained for 116/120 (97%) countries, with 89/116 (77%) including THM regulations. Routine monitoring was implemented in 47/89 (53%) of countries with THM regulations. THM data with a varying population coverage was obtained for 69/120 (58%) countries consisting of ∼5600 million inhabitants (76% of world's population in 2016). Population coverage was ≥90% in 14 countries, mostly in the Global North, 50-89% in 19 countries, 11-49% among 21 countries, and ≤10% in 14 countries including India, China, Russian Federation and Nigeria (40% of world's population). DISCUSSION: An enormous gap exists in THM regulatory status, routine monitoring practice, reporting and data availability among countries, especially between high- vs. low- and middle-income countries (LMICs). More efforts are warranted to regulate and systematically assess chemical quality of drinking water, centralize, harmonize, and openly report data, particularly in LMICs.Item Is our breathing optimal? : this dissertation is submitted for the degree of Doctor of Philosophy, School of Natural and Computational Sciences, Massey University, New Zealand(Massey University, 2019) Zaidi, Syed Muhammad FaheemOne of the open questions in relation to the control of amplitude and frequency of breathing is why a particular pattern of breathing is observed. This thesis explores the hypothesis that the particular combination of breathing frequency and amplitude realised, is optimal with respect to some objective function. Several objective functions have been suggested in the literature, such as the rate of work during inhalation, the average force exerted by the respiratory muscles, and the weighted sum of volumetric acceleration and work during inhalation; all of these objective functions were studied using 1D models and all provided physiologically acceptable minima under normal conditions. The thesis investigates optimal solutions of mathematical models that range from 2D to 6D and reflect more accurately the coupling between lung mechanics and gas exchange. It shows how published 6D and 5D models can be reduced to new 3D and 2D models. At its simplest, the 2D model consists of two piecewise linear differential equations. The use of higher dimension models require a new definition of the optimization problem as minimizing a given objective function subject to several constraints, such as satisfying the differential equations and maintaining one of the variables at a given average value. The optimal problem can be solved analytically in the case of the simplest 2D model, using concepts from optimal control theory. The analytical solution is used to verify a numerical algorithm that is then used to solve the more complex models. Solutions of the optimization problem for the different objective functions, previously suggested in the literature have been calculated. In all the optimal solutions found in this thesis, the duration of inhalation is equal to the duration of exhalation. However, under normal conditions, the time duration of inhalation is expected to be shorter than that of exhalation. This might be resolved by imposing additional constraints or by proposing a different hypothesis to explain why a particular pattern of breathing is observed.Item Low fluence UV-B as a positive regulator of photosynthesis in Arabidopsis thaliana : a thesis presented in partial fulfilment of the requirements for the degree of Doctor in Philosophy in Agriculture and Horticulture at Massey University, Palmerston North, New Zealand(Massey University, 2019) Sievers, Rixta F. T.UV-B radiation can induce a wide range of developmental responses in plants, and magnitudes of UV-B exposure can also vary greatly. Historically, research into the effects of UV-B radiation on photosynthetic processes has often utilised high fluence rates of UV-B, which have been frequently shown to impede photosynthetic performance and induce photosystem damage. More recently, a number of studies have focused on the impact of low fluence UV-B exposure, and have found that such treatments can be beneficial to photosynthesis by upregulating photosynthetic performance. The aim of this PhD was to understand the consequences of low fluence UV-B exposure on net photosynthetic rate and underlying mechanistic responses. We characterised the photosynthetic response to 0.5 μmol m⁻² s⁻¹ of UV-B and established that net photosynthetic rate increased by 12% in wild type Arabidopsis plants at 24hrs of UV-B exposure. Through analysis of knockout lines for the UV-B photoreceptor UVR8, we determined that the photosynthesis phenotype is dependent on the presence of UVR8. To determine how low fluence UV-B exposure mediates the increase in photosynthetic rate, transcriptomic analysis via RNA-seq was undertaken. Our analysis showed that UV-B exposure results in the upregulation of photosynthesis-associated genes during the initial exposure period. The most highly upregulated genes were related to chloroplast biogenesis and synthesis of photosynthetic proteins within the chloroplast, as well as chloroplastic oxidoreductase activity. We further investigated three of these candidates: RBF1, TOC33 and TFP, and found that each of those genes plays a role in the UV-B mediated increase of photosynthetic rate at 24hrs and that the upregulation of these genes in response to UV-B exposure is regulated by UVR8. Taken together, we describe here for the first time, that low fluence UV-B increases net photosynthetic rate through UVR8-mediated upregulation of key genes, resulting in increased synthesis of chloroplastic photosynthesis-associated proteins and chloroplastic oxidoreductase activity. This further extends our knowledge of UV-B plant-response and offers further potential for exploitation of UV-B photomorphogenesis in agriculture.Item Regulation of histidine catabolism in Pseudomonas fluorescens SBW25 : a thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Microbiology & Genetics at Massey University, Auckland, New Zealand(Massey University, 2019) NarenThe pathway of histidine utilization (hut) has been a model for studying bacterial gene expression, particularly the coordination between cellular carbon and nitrogen metabolisms. Early studies in enteric bacteria led to the concept of catabolite repression, which explains the inhibitory effects of glucose on the utilization of alternative carbon sources such as histidine and lactose. Briefly, transcription of hut genes is activated by the catabolite-activating protein (CAP) charged with cAMP and the NtrBC/NAC cascade when histidine is used as a source of carbon and nitrogen, respectively. However, this well-defined paradigm does not hold for many non-enteric bacteria, including the closely related Pseudomonas. This work aims to define the molecular basis of hut gene expression in Pseudomonas, using the plant growth-promoting bacterium P. fluorescens SBW25 as a model. Previous work identified all hut genes involved in histidine uptake and subsequent enzymatic breakdown, which are organized in three transcriptional units in the hut locus: hutF, hutCD and hutU-G. Like in enteric bacteria, histidine-induced expression of hut operons is mediated by the HutC repressor with urocanate, the first intermediate of the histidine degradation pathway, as the effector molecule. However, the precise interactions between HutC and its hut operator sites remain elusive; more importantly, recent progress suggests a new role of HutC in global gene regulation beyond histidine catabolism. Moreover, two two-component systems CbrAB and NtrBC are involved in hut activation, but it remains unknown whether they act in a direct or indirect manner. In this study, I first examined the molecular interactions between His6-tagged HutC protein and probe DNAs of the PhutU and PhutF promoters. Results of electrophoretic mobility shift assay (EMSA) and DNase I footprinting indicate that HutC binds to a consensus sequence of TGTA-N2-TACA (named Phut site), and involves complex oligomerization in response to varying concentrations of urocanate. A novel weak HutC binding sequence (termed Pntr site) was identified in the PhutF promoter, which may help strengthen the repression of hutF. Significantly, this Pntr site shows no sequence similarity to the previously recognized Phut site, instead it is homologous to the NtrC-binding consensus sequence (GCACCA-N3-TGGTGC). Next, the Phut consensus sequence was used to predict HutC target genes in the genome of P. fluorescens SBW25. This led to the identification of 88 candidate promoters, eight of which were subject to experimental verification by EMSA and DNase I footprinting. Phenotypic analysis of the hutC deletion mutant showed that hutC is involved in cell motilities. The data is consistent with the predicted global regulatory role of HutC. Histidine utilization poses a significant challenge as it produces excess nitrogen over carbon. The rate of histidine utilization (hut) thus must be carefully regulated. Here we show, for the first time, that expression of hut genes is positively regulated by two global regulators CbrAB and NtrBC in a direct manner, while subjecting to histidine concentration-dependent negative control of the HutC repressor. hut expression is further regulated at the post-transcriptional level by the CbrAB-CrcYZ-Crc/Hfq cascade in response to the presence of succinate (the most preferred carbon source for Pseudomonas). When growing in nutrient-complex conditions such as a minimal salts medium supplemented with succinate and histidine wherein histidine is the sole nitrogen but less-preferred carbon source, CbrAB is involved in directly activating hut transcription but indirectly repressing hut translation. Under this condition, NtrBC plays the dominant role in transcriptional activation of hut genes, but it requires assistance from the HutC repressor. A combination of genetic and biochemical analyses show that HutC acts as a governor to monitor and control the histidine catabolic rate, preventing production of excess ammonium and consequent inactivation of the NtrBC system. HutC additionally recognizes the NtrC binding site responsible for ntrBC expression, which provides a negative feedback for NtrBC autoregulation. Together, data presented in this thesis extend our understanding of carbon catabolite repression to the cellular nitrogen catabolism of Pseudomonas: carbon/nitrogen metabolic balance is maintained by the interplay of CbrAB and NtrBC at the hut operator site, and it requires the local regulator HutC to prevent hut expression from exceeding a critical upper limit. The finding that the HutC regulator is capable of recognizing two distinct DNA binding motifs (Phut and Pntr) has broader implications in gene regulation. Further biochemical analysis is required to unravel the molecular basis of the observed dual site recognition.Item Investigating eating behaviours as predictors of body composition and dietary intake in New Zealand European, Māori and Pacific women - the women's EXPLORE study : a thesis presented in partial fulfilment of the requirements for the degree Master of Science in Nutrition and Dietetics, Massey University, Albany, New Zealand(Massey University, 2018) Shepherd, Katrina JadeBackground/Aim: Internationally, eating behaviour has been linked with an optimal and adverse body composition in women. However no study to date has examined eating behaviour in female New Zealand ethnic groups. Therefore, the aim of this study was to investigate eating behaviours as predictors of different body composition factors and dietary intake in New Zealand European (NZE), Māori and Pacific women, aged 16-45 years, participating in the women’s EXPLORE study. Methods: Women (N=368) were assessed for basic anthropometry, total adiposity, regional adipose distribution and lean mass using height, weight, circumferences, dual x-ray absorptiometry and air-displacement plethysmography. Body composition profiles (normal-fat, hidden-fat and apparent-fat) were established using parameters of body mass indices and body fat percentages. The validated Three-Factor Eating Questionnaire (TFEQ) and New Zealand Women’s Food Frequency Questionnaire were both used to examine eating behaviour and dietary intake, respectively. The TFEQ examined Restraint (Flexible and Rigid), Disinhibition (Habitual, Emotional and Situational) and Hunger (Internal and External). Combinations of behaviour (sub-groups) were established from the main categories and also examined. Results: Restraint was significantly higher in NZE than Pacific women (p = 0.015). Disinhibition was significantly higher in the apparent-fat profile than normal-fat profile (p < 0.001). Likewise, Hunger was significantly higher in Pacific (p < 0.001) and the apparent-fat profile (p = 0.034) than NZE women and women with normal-fat profile, respectively. Adverse tendencies of Habitual Disinhibition, and External Hunger were more prominent in Pacific and the apparent-fat profile than NZE women and normal-fat profile, respectively (all p < 0.05). External Hunger was more prominent in the hidden-fat profile than normal-fat profile (p = 0.001). When accounting for age and ethnicity the most significant predictors of BMI and BF % were Restraint (p = 0.007 and p = 0.005 respectively), Disinhibition (both p < 0.001), Habitual Disinhibition (both p < 0.001) and Emotional Disinhibition (both p < 0.001). Non-ideal behaviour combinations (Low Restraint High Disinhibition and High Hunger High Disinhibition) generally corresponded to significantly higher body composition markers and dietary intake (p < 0.05). Pacific women were three times more likely to have High Hunger High Disinhibition than NZE women (p = 0.004). Low Restraint High Disinhibition and High Hunger High Disinhibition increased by 12% and 11%, respectively from the normal-fat profile to hidden-fat profile (both p < 0.001). Conclusions: The TFEQ eating behaviour categories, sub-categories and sub-groups can significantly vary between ethnicities and body composition groups. Tailored interventions to promote Restraint (particularly Flexible Restraint) and counteract Disinhibition (particularly Habitual Disinhibition and Emotional Disinhibition), Hunger (particularly External Hunger), Low Restraint High Disinhibition and High Hunger High Disinhibition could enhance eating behaviour and dietary intake and help optimise weight management in young New Zealand women.Item Human temperature regulation during exercise in the heat : effects of the menstrual cycle and ambient thermal profile : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy, School of Sport, Exercise and Nutrition, Massey University, Palmerston North, New Zealand(Massey University, 2018) Lei, Tze-HuanBehavioural thermoregulation is the most effective means with which we regulate our body temperature at rest and during exercise. Yet, research into behavioural thermoregulation during exercise is still at an emergent stage, as it has not included females, or investigated different thermal profiles. In particular, limited studies are available to describe the behavioural and physiological differences between dry and humid heat for both sexes. Furthermore, it remains unknown whether ambient humidity or temperature alone contribute to the initiation of the behavioural responses during exercise in the heat. Therefore, the first part of this thesis investigated the effects of endogenous and exogenous female ovarian hormones on behavioural and autonomic responses, in both dry and humid heat environments matched according to the heat stress index, WBGT (Chapter Five and Six). The results from Chapter Five clearly show that behavioural and autonomic responses were less affected by menstrual phase, but were affected by the environmental conditions. In particular, trained women reduced their power output in order to nullify the autonomic strain from a humid heat environment. Chapter Six then extended this observation to (trained) women taking combined hormonal contraception, compared to eumenorrheic women in Chapter Five. The results from Chapter Six indicate that greater autonomic strain was observed in women with hormonal contraception, compared to eumenorrheic women, in both dry and humid heat, whilst the behavioural response was similar between those two groups. Furthermore, the behavioural response was different between dry and humid heat, with power output being lower in the humid heat environment compared to dry heat. The second part of this thesis investigated the effects of ambient temperature per se on the interaction of thermoregulatory, cardiovascular and perceptual responses to exercise (Chapter Seven), as well as assessing different exercise modalities (variable-intensity versus fixed-intensity exercise) and their effects on thermoregulation when the duration and average power output were matched (Chapter Eight). The results from Chapter Seven indicate that thermoregulatory and cardiovascular responses were not affected by ambient temperature but that perception was, when vapour pressure was matched between two different thermal profiles. The results from Chapter Eight indicate that self-pacing (behaviour) did not modulate thermoregulatory strain, when both self-paced and fixed-intensity were matched at the same exercise intensity and duration. In conclusion, this thesis extends the knowledge-base on behavioural thermoregulation in trained women and also provides evidence that behavioural and autonomic thermoregulation is influenced more by vapour pressure than ambient temperature of the environment in men. Furthermore, the findings of this thesis confirm that behavioural thermoregulation is effective in modulating physiological strain only when there is a reduction in metabolic heat production.Item Vagal influences on respiratory reflexes : interaction of P.S.R. and R.A.R. on the inflation and deflation reflex, their role in linking respiratory cycles : and postvagotomy effect of P.D.G. : a thesis in partial fulfilment of the requirements for the degree of Master of Science, Massey University(Massey University, 1985) Jones, HeatherThere is evidence that changes in one respiratory cycle may influence subsequent cycles by a central mechanism. Thus the influence of P.S.R. and R.A.R. activity from within one respiratory cycle on subsequent cycles, which we have called "memory", needed to be examined in the determination of duration of expiration (tE) and inspiration (tI). this study was designed to investigate the relative roles of P.S.R. and R.A.R. stimulation in expiration influencing tI arnd tE over several subsequent breaths. In particular to investigate their role in linking respiratory cycles. In 14 anaesthetized spontaneously breathing rabbits we studied the response of tI and tE to +ve and -ve pressure pulses of 20KPa applied to the lung at various stages in expiration before and during P.S.R. block with S02. Before P.S.R. block, +ve pressure pulses early in expiration generally shortened tE containing the pulse, applied later +ve pressure pulses lengthened tE. Positive pressure pulses after P.S.R. block, and -ve pressure pulses before and after block always shortened tE. Regardless of sign of pulse tE was shortened in subsequent breaths before and after block. The inspiration after negative pulse application was usually lengthened. After effective block -ve pulses rarely lengthened tl. Large shortening of tE containing the pulse was usually followed bv a shortened tl. Positive pulses did not significantly effect the duration of tl. Regardless of sign of pulse tl was not usually changed but occasional large shortening occured in subsequent breaths before and after P.S.R. block. This indicates that the tE containing the stimulation is governed by a balance between P.S.R. and R.A.R. activity. The tI following t.he stimulus is governed by a balance between memory 11 of P.S.R. and R.A.R. activity. In the breaths following both tE and tI were influenced by memory of R.A.R. activity only. However "memory'' of strong R.A.R. activity is required to affect tI. During this study it was intended to use phenyldiguanide (P.D.G.) to test J receptor patency. Intravenous injections of P.D.G. have been used to provoke respiratory reflexes, these have been considered to be due mainly to stimulation of type J receptors. However although most workers demonstrated that vagotomy abolished or reduced these reflexes, some still had significant response to P.D.G. after vagotomy. A study was conducted to resolve this difference and demonstrate the sites at which P.D.G. acts in rabbits. We measured tE and tI in 10 anaesthetized spontaneously breathing rabbits. 50 g/kg P.D.G. was given intravenously (via a catheter with its tip close to the right atrium) to the intact rabbit; after blocking epicardial receptors; immediately after bilateral cervical vagotomy; 15 minutes after vagotomy; and after the glossopharyngeal nerves were cut near the base of the skull. The respiratory reflex after injection of xylocaine, 15 minutes after vagotomy, and after cutting the glossopharyngeal nerves was as pronounced as in the intact state, and consisted of an increase in frequency almost totally due to a reduction in tE. With injections given up to 3 minutes after bilateral vagotomy the respiratory response was greatly attenuated and variable. We suggest this question of timing may contribute to the differences seen by different groups of workers. It is clear that intravenous injection of P.D.G. is not an adequate test of J receptor presence in the rabbit.Item The transcriptional regulation of maspin : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Biochemistry at Massey University, Palmerston North, New Zealand(Massey University, 2004) Hollings, AndrewMaspin (mammary serine protease inhibitor) is a tumour suppressing member of the serpin superfamily. Maspin is expressed in normal breast and prostate cells, but reportedly down regulated during progression of cancer in these tissues. Maspin has been shown to inhibit cellular migration and invasion in vitro; while in vivo, maspin has been shown to inhibit tumour growth, metastasis, and angiogenesis. Maspin also plays a role in the sensitisation of cells to induced apoptosis. These functions of maspin are independent of serine protease inhibition; however the cellular mobility function is dependent on an intact reactive site loop. Despite this knowledge, the molecular mechanisms for all reported functions of maspin are currently unknown. Maspin is reported to be transcriptionally regulated: to date Ets, Ap1, and p53 transcription factors have been shown to activate transcription of maspin by binding directly to the promoter. Androgen is reported to be a negative regulator through the binding of the androgen receptor to a hormone response element within the promoter. This hormone response element is also responsible for an increase in maspin expression in response to tamoxifen, an anti-oestrogen drug. Transcriptional regulation of maspin has also been reported to be activated by other molecules, including gamma linolenic acid, manganese containing super-oxide dismutase, and nitric oxide, the mechanisms of regulation by these molecules is unknown. Loss of maspin expression in cancerous cells lines has been attributed to loss of one or more of the activating factors, and aberrant methylation of cytosine residues resulting in chromatin compaction. This study investigated the transcriptional regulation of maspin, with the aim of identifying transcriptional effectors important to the regulation of the gene. Identification of such factors may help identify a pathway in which maspin exerts its tumour suppressor functions. To this end, the maspin promoter was cloned and functional assays carried out. identifying several putative regions of the maspin promoter which may be important for the regulation of the gene. To date, the precise activator/repressor binding sites and the cognate proteins responsible for this regulation are unidentified.Item Role of N-terminal domains of p400 ATPase in the ATM interaction and DNA damage response : a thesis presented in partial fulfillment of the requirements for a the degree of Master of Science (MSc) in Genetics at Massey University, Manawatū, New Zealand(Massey University, 2016) Weber, Lauren ElizabethEfficient repair of damaged DNA and preservation of genomic integrity is integral in the maintenance of proper cellular function and prevention of unrestricted cell proliferation. One critical threat to the stability of the genome is the double strand break (DSB), arguably one of the most cytotoxic lesions to DNA. Interference with the DSB repair mechanism can lead to dysregulation of cellular systems and the prospective development of malignancies. Two critical proteins in DBS repair are the Ataxia Telangiectasia Mutated (ATM) kinase, a serine/threonine kinase from the Phosphatidylinositol 3-Kinase-related Kinase (PIKK) family, and p400, an ATPase chromatin remodeler. ATM is one of the first responders to DSBs and is responsible for the phosphorylation of a multitude of protein substrates including the histone variant H2AX. Beyond its phosphorylation ability, ATM has been proposed as a potential shuttle for other repair machinery, aiding in the early and efficient recruitment of proteins to the DNA damage foci. One such proposed protein is p400. The exact role of p400 in DSB repair is unknown but previous studies show that there is a decrease in repair efficiency in its absence. A prospective interaction is supported by previous studies in which p400 and p400 N-terminal derivatives co-immunoprecipitate with ATM in vivo in HEK293T cells. This study aimed to confirm the interaction of ATM and p400 N-terminal derivatives in vitro and explore the functional implications of the association in vivo in U2OS cells. It was not possible to isolate full-length p400 derivatives in vitro and thus no conclusive results were obtained. Functional assays revealed the ability of one p400 fragment, F1, to inhibit DNA repair and cell proliferation after DNA double-strand break induction with bleomycin. Ectopic expression of the other two p400 N-terminal fragments, F2 and F3, induced an inhibition of cell proliferation under standard growth conditions. Although no conclusive results were acquired, a trend emerged suggesting that N-terminal fragment F1 is able to interfere with ATM protein-protein interactions resulting in a decrease in the efficiency of the DNA damage response and repair. These results implicate F1 as a potential target for further research in both DNA repair and cancer therapy.Item Aq2 : a highly water-soluble plant growth regulator from the pollen of Pinus radiata : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Chemistry at Massey University(Massey University, 1974) Tse, Phillip GordonAq2; a highly water-soluble plant growth regulator from the pollen of Pinus radiata Aq2 was detected in crude aqueous extracts from the pollen of Pinus radiata by Sweet and Lewis (1971). These workers noted Aq2 possessed some properties of both gibberellins and cytokinin-like compounds and was probably involved in the regulation of pollen tube growth. A further study was under-taken by Gallagherand Aldersley (1972) and these workers concluded after a preliminary investigation that Aq2 was most probably a cytokinin. The purpose of this thesis was to further investigate the nature of Aq2. The physiological role and chemical composition of pollen, with special reference to P. radiata was studied, and a review of plant growth regulators carried out with a view to classifying Aq2 into one of the four groups. A survey of possible isolation techniques was also made. Anion and cation exchange columns were run at various pH's and a portion of the activity attributable to Aq2 was found to bind to an anion column at pH 8.5.The remainder passed straight through the column. An aqueous alcohol treatment has been employed to remove some of the excess carbohydrate material, and freeze drying was shown not to affect the activity of Aq2. Chemical evidence tends to mitigate against Aq2 being a gibberellin; however, the possibility that Aq2 is a cytokinin has not yet been ruled out. No additional physiological studies have been carried out since those of Sweet and Lewis(1971); however, good responses are still obtained in the radish cotyledon assay for cytokinins. If Aq2 is indeed a cytokinin it does not appear to resemble any of those known to date.