Transition of hemoglobin between two tertiary conformations: The transition constant differs significantly for the major and minor hemoglobins of the Japanese quail (Cortunix cortunix japonica)

Abstract We demonstrate that 5,5′-dithiobis(2-nitrobenzoate) -DTNB -reacts with only CysF9[93]β and CysB5[23]β among the multiple sulfhydryl groups of the major and minor hemoglobins of the Japanese quail (Cortunix cortunix japonica). K equ , the equilibrium constant for the reaction, does not differ very significantly between the two hemoglobins. It decreases 430-fold between pH ≈ 5.6 and pH ≈ 9: from a mean of 7 ± 1 to a mean of 0.016 ± 0.003. Quantitative analyses of the K equ data based on published X-ray and temperature-jump evidence for a tertiary structure transition in liganded hemoglobin enable the calculation of K rt , the equilibrium constant for the r ←→ t tertiary structure transition. K rt differs significantly between the two hemoglobins: 0.744 ± 0.04 for the major, 0.401 ± 0.01 for the minor hemoglobin. The mean pK a s of the two groups whose ionizations are coupled to the DTNB reaction are about the same as previously reported for mammalian hemoglobins

Spatial variability of solar quiet fields along 96° magnetic meridian in Africa:results from MAGDAS

We have used chains of Magnetic Data Acquisition System (MAGDAS) magnetometer records of the horizontal (H) and vertical (Z) magnetic field intensities during September 2008 to August 2009 (year of deep minimum) across Africa to study their variability during the quietest international days, which coincidently associated with the sudden stratospheric warming (SSW) event in January 2009. This selection of the most international quiet days is indicative of 80% that are strongly associated with days when unusually strong and prolonged sudden SSW event occurs in January 2009. Interestingly, in January, a significant magnitude depletion of solar quiet (Sq) equivalent current was observed near noon hours around the magnetic equator (Addis Ababa, ABB) compared to any other months along with a consistent significantly reduced value across the Northern Hemisphere and moderate decrease at the Southern Hemisphere. Also, we found that Nairobi and Dar es Salaam at the Southern Hemisphere, which are close to ABB (dip equator), are strongly prone to westward electric field compared to the magnetic equator and Khartoum at the Northern Hemisphere. Significant negative values of MSq(Z) magnitudes observed near noon hours at Hermanus indicate the presence of induced currents that suggest ocean effects along with reversal to significant positive values in the afternoon, which subsided before 1800 LT in almost all the months, indicate stronger influence of ionospheric currents. On seasonal variability of Sq(H), a slight depression at ABB during September equinox is one of the evidences of seasonal Sq focus shift. Latitudinal variability of Sq near-noon hours was also investigated

Experience of taking care of children exposed to HIV: a trajectory of expectations

OBJETIVO: conhecer a experiência do cuidador/mãe em relação ao cuidado para com a criança exposta ao vírus da imunodeficiência humana por transmissão vertical, na trajetória pós-natal. MÉTODO: pesquisa qualitativa, que utilizou o Interacionismo Simbólico como referencial teórico. Foram realizadas entrevistas com 39 cuidadores de crianças expostas ao vírus da imunodeficiência humana e em seguimento em um serviço especializado. Os dados foram analisados pela análise de conteúdo indutiva. RESULTADOS: apreenderam-se quatro categorias que reportam à experiência solitária de manuseio da terapia antirretroviral da criança, no que se refere principalmente à ausência ou incompletude de informações recebidas; estar atento aos cuidados, que incluem o uso da profilaxia para pneumonia, vacinas e outros restritos à interação mãe/criança; querer omitir a presença do vírus da imunodeficiência humana pelo medo do preconceito e olhar o futuro e temer a doença. CONCLUSÃO: a presença do vírus da imunodeficiência humana e a ameaça dessa infecção na criança são capazes de gerar apreensão e tantos outros sentimentos como medo, culpa e ansiedade no cuidador. Os profissionais de saúde precisam trabalhar conjuntamente com a mãe para o enfrentamento das demandas e sofrimentos. Assim, o tratamento para evitar a transmissão vertical será eficiente e a mãe, juntamente à criança, viverá essa trajetória com apoio, apesar da apreensão pelo resultado.OBJETIVO: conocer la experiencia del cuidador/madre en relación al cuidado de niño expuesto al VIH por transmisión vertical en la trayectoria posnatal. MÉTODO: investigación cualitativa, que utilizó el Interaccionismo Simbólico como referencial teórico. Fueron realizadas entrevistas con 39 cuidadores de niños expuestos al VIH y que eran acompañados en un servicio especializado. Los datos fueron analizados por el análisis de contenido inductivo. RESULTADOS: se encontraron cuatro categorías que informan sobre la experiencia solitaria de la administración de la terapia antirretroviral del niño, en lo que se refiere principalmente a: la ausencia o a informaciones incompletas recibidas; al estar atento a los cuidados, que incluyen el uso de la profilaxis para neumonía, vacunas y otros restringidos a la interacción madre-niño; al querer omitir la presencia del VIH por miedo al prejuicio; y al mirar al futuro y temer a la enfermedad. CONCLUSIÓN: la presencia del VIH y la amenaza de infectar al niño son capaces de generar preocupación y varios otros sentimientos en el cuidador, como miedo, culpa y ansiedad. Los profesionales de la salud precisan trabajar conjuntamente con la madre para el enfrentamiento de las demandas y sufrimientos. Así, el tratamiento para evitar la transmisión vertical será eficiente y la madre con el niño vivirán esa trayectoria con apoyo, a pesar de la preocupación por el resultado.'OBJECTIVE: to learn about the experience of caregivers/mothers providing care to infants exposed to HIV through vertical transmission. METHODS: this qualitative study used Symbolic Interactionism as the theoretical framework. A total of 39 caregivers of children exposed to HIV in follow-up at a specialized service were interviewed. Data were analyzed through inductive content analysis. RESULTS: four categories were identified that report on the lonely experience of handling the child's antiretroviral therapy, mainly due to a lack of information or incomplete information; being attentive to required care, such as the use of prophylaxis for pneumonia, vaccines, and other practices restricted to the mother-child interaction; the desire to omit the HIV out of fear of prejudice and fear of the disease, considering future prospects. CONCLUSION: the HIV and the threat this infection may affect the child cause apprehension and feelings such as fear, guilt and anxiety in the caregivers. Healthcare workers need to work together with mothers so they are able to cope with demands and distress. Only then will the treatment to avoid vertical transmission be efficient and will mother and child be supported during the process, despite apprehension with the outcome

Nanochitosan derived from marine bacteria

Nanochitosans are polysaccharides produced by the alkalescent deacetylation of chitin and comprise a series of 2‐deoxy‐2 (acetylamino) glucose linked by ß‐(1‐4) glycosidic linkages. These are naturally formed from the deacetylation of shellfish shells and the exoskeleton of aquatic arthropods and crustaceans. Reports of chitosan production from unicellular marine bacteria inhabiting the sea, and possessing distinct animal‐ and plant‐like characteristics abound. This capacity to synthesize chitosan from chitin arises from response to stress under extreme environmental conditions, as a means of survival. Consequently, the microencapsulation of these nanocarriers results in new and improved chitosan nanoparticles, nanochitosan. This nontoxic bioactive material which can serve as an antibacterial agent, gene delivery vector as well as carrier for protein and drug release as compared with chitosan, is limited by its nonspecific molecular weight and higher composition of deacetylated chitin. This chapter highlights the biology and diversity of nanochitosan‐producing marine bacteria, including the factors influencing their activities, survival, and distribution. More so, the applications of marine bacterial nanochitosans in transfection and gene delivery; wound healing and drug delivery; feed supplement development and antimicrobial activity are discussed

Utilization of nanochitosan in the sterilization of ponds and water treatment for aquaculture

Water pollution constitutes the leading cause of infant mortality, neonatal deformities, and shrinkage of man’s average life expectancy. Pollutants come from point and nonpoint sources; and water pollution arises from the discharge of wastewater containing undesirable impurities used for domestic, agricultural, and industrial purposes. More so, high nutrient and wastewater runoffs from fish production systems contribute to the fouling and eutrophication of recipient water bodies. Hence, aquaculture which is inextricably linked to the natural environment is challenged by the dearth of appropriate water quantity and quality, militating against fish, and fishery production. Nanochitosans as polysaccharides produced by the alkalescent deacetylation of chitin, comprise a series of 2-deoxy-2 (acetylamino) glucose linked by ß-(1-4) glycosidic linkages. They are naturally formed from the deacetylation of shellfish shells and exoskeletons of aquatic arthropods and crustaceans. The unique attributes of chitin confer a wide range of biotechnological applications on the polymer, observed in flocculation as a wastewater treatment and purification route initiated by chitosan. This chapter highlights nanochitosan properties of aquaculture relevance; and elucidates the purification potentials of nanochitosan, compared to inorganic coagulants and organic polymeric flocculants. Effects of chitosan on contaminants and microorganisms, as well as applications in fish pathogens detection, fish disease diagnosis, and control are discussed