Ligation induced matrix-metalloproteinase-9 activity in peripheral frog nervous system

Matrix metalloproteinases (MMPs) are endopeptidases that cleave matrix, soluble and membrane-bound proteins and are regulated by their endogenous inhibitors the tissue inhibitors of MMPs (TIMPs). MMP-2 and MMP-9 are two of the MMPs which are essential to contribute to inflammatory and degenerative processes in injured nerves. The aim of the present study was to examine expression and activities of MMP-2 and MMP-9 in the injured and control groups frog sciatic nerves using gelatin zymography. Our investigation demonstrated for the first time as far as we know the expression of MMP-2 and MMP-9 in frog sciatic nerve. The expression and activity of MMP-9 were increased two fold on average following ligation. By contrast, MMP-2 activities remained unchanged. These findings suggest that we can consider MMP-9 as a marker for degenerative changes that follow nerve ligation in frog nerve.     

Induction and comparison of different in vitro morphogenesis pathways using embryo of cumin (<Emphasis Type="Italic">Cuminum cyminum</Emphasis> L.) as a model material

In this study, using cumin embryo as explant and manipulating plant growth regulators (PGRs) in regeneration medium, the main in vitro morphogenesis pathways including direct shoot organogenesis, direct somatic embryogenesis, indirect somatic embryogenesis, and indirect shoot organogenesis were obtained. The effects of PGRs, subculture, and light on the induction and progression of different pathways were studied in detail. Direct shoot organogenesis occurred on the meristematic zone, while direct somatic embryogenesis was observed on hypocotyl part of cumin embryo (more differentiated part). Application of BAP (0.1 mgl⁻¹) was the sole triggering factor for induction of callus and indirect regeneration pathways. Exogenous IAA played the central role in the direct somatic embryogenesis pathway; however, the combined effects of IAA and NAA along with the high endogenous cytokinin level resulted in direct shoot organogenesis. Subculturing revealed accelerating effects on direct somatic embryogenesis pathway and callus formation. Conversely, subculturing had negative effect on direct shoot organogenesis pathway. In certain combinations of PGRs, like 0.4 mgl⁻¹ IAA + 0.4 mgl⁻¹ NAA, co-induction and co-regeneration of different pathways were observed. Investigation of genotype dependencies of different pathways showed that direct pathways are more genotype-dependent, stable, and faster than indirect pathways. This research presents the embryo of cumin as a convenient model material for induction and comparison of different morphogenesis pathways.     

A grape berry (Vitis vinifera L.) cation/proton antiporter is associated with berry ripening

We have cloned and characterized VvNHX1, a gene encoding a vacuolar cation/H(+) antiporter from Vitis vinifera cv. Cabernet Sauvignon. VvNHX1 belongs to the vacuolar NHX protein family and showed high similarity to other known vacuolar antiporters. The expression of VvNHX1 partially complements the salt- and hygromycin-sensitive phenotypes of an ena1-4 nhx1 yeast strain. Immunoblots of vacuoles of yeast expressing a VvNHX1, together with the expression of a VvNHX1-GFP (green fluorescent protein) chimera demonstrated that VvNHX1 localized to the vacuoles. VvNHX1 displayed low affinity K(+)/H(+) and Na(+)/H(+) exchange activities (12.8 and 40.2 mM, respectively). The high levels of expression of VvNHX1 during the véraison and post-véraison stages would indicate that the increase in vacuolar K(+) accumulation, mediated by VvNHX1, is needed for vacuolar expansion. This process, together with the rapid accumulation of reducing sugars, would drive water uptake to the berry and the concomitant berry size increase, typical of the post-véraison stage of growth.     

Evaluation of culture conditions for cellulase production by two Trichoderma reesei mutants under solid-state fermentation conditions

Response surface methodology (RSM) was used to evaluate the effects of fermentation parameters for cellulase production by Trichoderma reesei QM9414 and T. reesei MCG77 in solid-state fermentation using rice bran as substrate. Initial pH, moisture content and temperature were optimized using filter paper activity (FPA) as response. Statistical analysis of the results for T. reesei QM9414 showed that only moisture content had significant effect on cellulase activity and had a linear effect on enzyme activity (maximum enzyme activities were obtained at 70% moisture content). The results for T. reesei MCG77 showed that temperature and moisture content were the most significant parameters for cellulase activity. The optimum cellulase production was in the temperature range of 25-30 degrees C and moisture content between 55% and 70%. After the optimization, the FPA in T. reesei MCG77 was increased by 2.5 folds compared to that of T. reesei QM9414.     

Expression of Cre recombinase in chondrocytes causes abnormal craniofacial and skeletal development

The cranial base synchondroses are growth centers that drive cranial and upper facial growth. The intersphenoid synchondrosis (ISS) and the spheno-occipital synchondrosis (SOS) are two major synchondroses located in the middle of the cranial base and are maintained at early developmental stages to sustain cranial base elongation. In this study, we report unexpected premature ossification of ISS and SOS when Cre recombinase is activated in a chondrocyte-specific manner. We used a Cre transgenic line expressing Aggrecan enhancer-driven, Tetracycline-inducible Cre (ATC), of which expression is controlled by a Col2a1 promoter. Neonatal doxycycline injection or doxycycline diet fed to breeders was used to activate Cre recombinase. The premature ossification of ISS and/or SOS led to a reduction in cranial base length and subsequently a dome-shaped skull. Furthermore, the mice carrying either heterozygous or homozygous conditional deletion of Tsc1 or Fip200 using ATC mice developed similar craniofacial abnormalities, indicating that Cre activity itself but not conditional deletion of Tsc1 or Fip200 gene, is the major contributor of this phenotype. In contrast, the Col2a1-Cre mice carrying Cre expression in both perichondrium and chondrocytes and the mice carrying the conditional deletion of Tsc1 or Fip200 using Col2a1-Cre did not manifest the same skull abnormalities. In addition to the defective craniofacial bone development, our data also showed that the Cre activation in chondrocytes significantly compromised bone acquisition in femur. Our data calls for the consideration of the potential in vivo adverse effects caused by Cre expression in chondrocytes and reinforcement of the importance of including Cre-containing controls to facilitate accurate phenotype interpretation in transgenic research.

     

Contamination of breast milk with lead,mercury, arsenic,and cadmium in Iran: a systematic review and meta-analysis

BioMetals - Breast milk is a complete food for the development of the newborn, but it can also be an important route for environmental pollutants transmission to the infants. This study was aimed...     

Development of optical biosensor technologies for cardiac troponin recognition

Acute myocardial infarction (AMI) is the leading cause of death among cardiovascular diseases. Among the numerous attempts to develop coronary marker concepts into clinical strategies, cardiac troponin is known as a specific marker for coronary events. The cardiac troponin concentration level in blood has been shown to rise rapidly for 4–10 days after onset of AMI, making it an attractive approach for a long diagnosis window for detection. The extremely low clinical sensing range of cardiac troponin levels consequently makes the methods of detection highly sensitive. In this review, by taking into consideration optical methods applied for cardiac troponin detection, we discuss the most commonly used methods of optical immunosensing and provide an overview of the various diagnostic cardiac troponin immunosensors that have been employed for determination of cardiac troponin over the last several years.     

Empathy in UK medical students: differences by gender, medical year and specialty interest

The importance of empathetic communication in the context of patient care has been suggested as a crucial element in the delivery of high-quality medical care. Although some countries have measured empathy among medical students, little is known formally about the state of affairs regarding empathy in the UK with regard to gender, medical years and speciality. This paper presents the results from a cross-sectional study that explored the relationship between undergraduate medical students' empathy scores relevant to gender, medical school year and future career ambitions. The Jefferson Scale of Physician Empathy, a self-administered questionnaire, was used for collecting data. It was decided to incorporate the scale into a web application that was only accessible through a confidential hyperlink. A total of 853 (68.2%) medical students completed the survey. Female students (n=470) scored significantly (t((819))=-6.63; 95% CI=-0.30, -0.16) higher than male students (n=351). No significant differences were observed between empathy mean scores and medical school year. Students choosing people-oriented specialities had significantly higher mean scores in comparison to students preferring technology oriented specialities. Three hypotheses were tested in this study. The hypothesis that female students would score higher than male students was supported by the results. The findings did not support the hypothesis that empathy scores decline during the medical school years. Finally, the findings did support the hypothesis that those preferring peopleoriented specialities would score higher on the empathy scale than students choosing technology oriented specialities. Some recommendations are made and the limitations of study are discussed.