Expansins are extracellular proteins which are able to loosen cell walls thus making possible the extension and stress relaxation of plant walls. Expansins are classified on the basis of sequence similarities and substrate specificity into two subfamilies of a- and b-expansins. The expansins? mode of action is based on the weakening of hydrogen bonds between cellulose microfibrils and on interacting matrix polymers, especially hemicelluloses. However, they do not reveal any hydrolytic or proteolytic activity. The activity of expansins is decisive for the control of plant cells? shape, and thus these proteins are thought to be an important component of biochemical machineries controlling cell growth and differentiation, as well as plant morphogenesis and development. This article reviews the advances made since the discovery of expansins and describes their characteristic features, including protein structure and biochemical mode of action, molecular organisation of expansin-coding genes, and biological functions of these unusual proteins.
Proteomics is a scientific discipline that focuses on the large-scale study of proteins, particularly their structures, functions and interactions. The proteome is the full complement of proteins expressed by genome. During the last decade, thanks to subset of proteomic techniques and workflows, it has been possible to identify: diagnostic protein biomarkers, potential therapeutic targets and also biotechnologically important plant proteins, like those that give a plant resistance to drought. Over the last years, proteomics has generated a relatively large number of reviews on technical aspects and concepts. Although total automation and reproducibility are possible, the protocols of protein isolation and separation are sample specific. Moreover, most of them address the development of optimal sample preparation protocols of mammalian cells and tissue. In contrast, plant proteomics is still in its infancy, probably because plant material is very recalcitrant. The objective of this review is to pay attention to some methodological aspects of proteomic analyses using 2DE and mass spectrometry, especially in the case of plant material.
Transfusions of blood or blood products are commonly used in medicine, but being biological materials they carry a risk of transmitting infections ? viral, bacterial, parasitic, as well as prions. Laboratory tests used for screening of donated blood for viral infections at present cannot detect all infectious units. Criteria for selection of blood donors therefore must be very strict, while methods of inactivation of viruses and laboratury assys for detection of their presence must be improved. Indications for blood transfusion should be restricted.
An increase in femoral and tibio/fibular bone mass following periosteal membrane stimulation by Moloney sarcoma virus inoculation into thigh muscles of mice was measured in situ on formalin fixed excised hind limbs using a Hologic 4500A Fan Beam X-ray bone densitometer adapted for small bone samples. These results were verified by measurements of constant dry bone mass of the same bones liberated from soft limb tissues by NaOH hydrolysis. There was no consistent data correlation found between the DEXA scan and dry bone mass evaluations. It is concluded that the sensitivity of the DEXA measurement is unsuitable when assessing very small bone samples, weighing merely 20-30 mg.
Introduction: Detection of human cytomegalovirus (CMV, HHV-5) DNA in clinical specimens is considered a cornerstone in the diagnosis of HHV-5 disease. The present study compared two quantitative methods used for diagnosing cytomegalovirus infection in a 21-year-old woman with chronic myeloid leukemia after an unrelated umbilical cord blood transplantation. Materials and Methods: Blood samples were tested for the presence of HHV-5 DNA using the LightCycler PCR, the quantitative Eclipse? CMV DNA Detection Kit, and a qualitative in-house PCR assay using primers that amplify part of the HHV-5 MIE gene. Results: Results from samples containing a low cytomegalovirus load were more accurate with the LightCycler test than those obtained with the Eclipse? test, which underestimated the viral load of samples containing low DNA copy numbers. Conclusions: These findings underline the value of novel PCR methods used in current therapeutic procedures and in monitoring antiviral therapy with nucleoside analogs. The high level of sensitivity, specificity, accuracy, and rapidity provided by the LightCycler instrument are favorable for the use of this system in the detection of HHV-5 DNA in clinical specimens.
Human herpesvirus 6 (HHV-6) has been recognized as a potentially significant pathogen in hemopoietic stem cell transplant (HSCT) recipients. Different clinical manifestations have been described, including fever, skin rash, bone marrow suppression, and encephalitis. Materials and Methods: A retrospective review of a group of 26 adult recipients of allogeneic HSCTs was conducted. Serum samples taken before transplant were examined for the presence of specific anti-HHV-6 IgM and IgG antibodies. After transplantation, quantitative real-time PCR was used to determine viral load in plasma samples from days 0?180 post-transplant. Results: HHV-6 DNA was detected in plasma samples in 8 (30%) of the 26 recipients between days 18 and 40 after transplantation. All of them developed fever of unknown origin and over 50% had graft-versus-host disease features. Three individuals from this group died during detectable HHV-6 viremia. Another two recipients showed a single positive PCR result at a later time. Infection with HHV-6 was thus confirmed in 10 (38.5%) of the 26 graft recipients. Conclusions: There is a high frequency of detectable HHV-6 viral load in stem cell transplant recipients in Poland. Further investigation to monitor HHV-6 reactivation in graft recipients will be important to improve outcome for these patients.
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