Stability of casein micelles cross-linked with genipin: a physicochemical study as a function of pH

Chemical or enzymatic cross-linking of casein micelles (CMs) increases their stability against dissociating agents. In this paper, a comparative study of stability between native CMs and CMs cross-linked with genipin (CMs-GP) as a function of pH is described. Stability to temperature and ethanol were investigated in the pH range 2.0-7.0. The size and the charge ($\zeta$-potential) of the particles were determined by dynamic light scattering. Native CMs precipitated below pH 5.5, CMs-GP precipitated from pH 3.5 to 4.5, whereas no precipitation was observed at pH 2.0-3.0 or pH 4.5-7.0. The isoelectric point of CMs-GP was determined to be pH 3.7. Highest stability against heat and ethanol was observed for CMs-GP at pH 2, where visible coagulation was determined only after 800 s at 140 $^\circ$C or 87.5% (v/v) of ethanol. These results confirmed the hypothesis that cross-linking by GP increased the stability of CMs.Comment: 5 pages, 2 figures, International Dairy Journal, 201

Avaliação in vivo da interação leucócito-endotélio mesentérico após ligadura e punção cecal e remoção cirúrgica do foco sééptico

PURPOSE: Cecal ligation and puncture (CLP) has been used as a useful model for the induction of polymicrobial sepsis. Necrotic tissue resection and peritoneal lavage (REL) are the surgical procedures for controlling perforated appendicitis. The aim of this study was to evaluate leukocyte-endothelial interactions in the rat mesentery in vivo after CLP and REL. METHODS: Thirty-seven male Wistar rats (250-300 g) underwent laparotomy and were randomly assigned to the following groups: 1) SHAM; 2) CLP: animals submitted to CLP, 3) CLP+REL: animals submitted to CLP and REL. Mesenteric leukocyte-endothelial interactions were studied by intravital microscopy assessed once in each animal (3-5 postcapillary venules, 15-25 µm diameter) 24 hours after intervention. Follow-up was performed in all animals; this included analysis of glycemia, lactate, hematocrit, white blood cell count as well as a functional score that was the sum of scoring on the following parameters: alertness, mobility, piloerection, diarrhea, encrusted eyes, and dirty nose and tail. RESULTS: None of the animals showed significant changes in body weight (265 ± 20 g) or in hematocrit levels (46% ± 2%) during the experimental protocol. Compared to SHAM animals, CLP animals showed an increased number of rolling (2x), adherent, and migrating leukocytes (7x) in the mesenteric microcirculation, an increase in blood glucose (136 ± 8 mg/dL), lactate (3.58 ± 0.94 mmol/L), white cell count (23,570 ± 4,991 cells/mm³) and functional alterations (score 11 ± 1), characterized by impaired alertness and mobility, and presence of piloerection, diarrhea, encrusted eyes, and dirty nose and tail. The REL procedure normalized the number of rolling, adherent, and migrated leukocytes in the mesentery; glycemia; lactate; and white blood cell count. The REL procedure also improved the functional score (7 ± 1). CONCLUSION: Local and systemic inflammation was induced by CLP, while REL completely overcame the inflammatory process.OBJETIVO: O procedimento de ligadura cecal e perfuração (CLP) tem sido usado como um modelo útil de indução de sepse polimicrobiana. A ressecção do tecido necrosado e lavagem peritoneal (REL) são procedimentos cirúrgicos freqüentemente utilizados para controlar uma apendicite perfurada. O objetivo desse estudo foi avaliar in vivo as interações leucócito-endotélio no mesentério de ratos após a CLP e REL. MÉTODOS: Trinta e sete ratos Wistar machos (250-300 g) foram submetidos à laparotomia e aleatoriamente divididos em grupos: 1) SHAM, 2) CLP: ratos submetidos à CLP, 3) CLP+REL: animais submetidos à CLP e REL. As interações leucócito-endotélio no mesentério foram estudadas através de microscopia intravital somente uma vez em cada animal (3-5 vênulas pós-capilares, 15-25 µm diâmetro), 24-horas após as intervenções. A evolução clínica foi realizada em todos os animais, incluindo glicemia, lactato, hematócrito, número total de células brancas e um escore funcional, o qual foi considerado como a somatória dos seguintes parâmetros: estado de alerta, mobilidade, piloereção, diarréia, olhos encrustados, e nariz e cauda sujos. RESULTADOS: Os animais não apresentaram alterações significantes no peso (265 ± 20 g) e hematócrito (46 ± 2%) ao longo do estudo. Comparados ao SHAM, os animais CLP apresentaram aumento no número de leucócitos em rolamento (2x), aderidos (7x) e migrados (7x) na microcirculação mesentérica, aumentos da glicemia (136 ± 8 mg/dL), lactato (3,58 ± 0,94 mmol/L), leucocitose (23.570 ± 4.991 células/mm³) e alterações clínicas (escore 11±1), caracterizadas por comprometimento do estado de alerta e mobilidade, e presença de piloereção, diarréia, olhos encrustados, nariz e cauda sujos. REL normalizou o número de leucócitos em rolamento, aderidos e migrados no mesentério, a glicemia, o lactato e o número de leucócitos circulantes. REL também melhorou o escore clínico (7 ± 1). CONCLUSÃO: A CLP induziu inflamação local e sistêmica. A REL resolveu, por completo, o processo inflamatório

Leaf heteroblasty in Passiflora edulis as revealed by metabolic profiling and expression analyses of the microRNAs miR156 and miR172

Juvenile-to-adult phase transition is marked by changes in leaf morphology, mostly due to the temporal development of the shoot apical meristem, a phenomenon known as heteroblasty. Sugars and microRNA-controlled modules are components of the heteroblastic process in Arabidopsis thaliana leaves. However, our understanding about their roles during phase-changing in other species, such as Passiflora edulis, remains limited. Unlike Arabidopsis, P. edulis (a semi-woody perennial climbing vine) undergoes remarkable changes in leaf morphology throughout juvenile-to-adult transition. Nonetheless, the underlying molecular mechanisms are unknown.Here we evaluated the molecular mechanisms underlying the heteroblastic process by analysing the temporal expression of microRNAs and targets in leaves as well as the leaf metabolome during P. edulis development.Metabolic profiling revealed a unique composition of metabolites associated with leaf heteroblasty. Increasing levels of glucose and α-trehalose were observed during juvenile-to-adult phase transition. Accumulation of microRNA156 (miR156) correlated with juvenile leaf traits, whilst miR172 transcript accumulation was associated with leaf adult traits. Importantly, glucose may mediate adult leaf characteristics during de novo shoot organogenesis by modulating miR156-targeted PeSPL9 expression levels at early stages of shoot development.Altogether, our results suggest that specific sugars may act as co-regulators, along with two microRNAs, leading to leaf morphological modifications throughout juvenile-to-adult phase transition in P. edulis