Pass the jelly rolls

The crystal structure of the vaccinia virus D13 protein presented by Bahar et?al. in this issue of Structure displays fused "virus jelly roll" folds, ubiquitous among dsDNA icosahedral viruses. Although D13 is not present in the mature virus, its structure suggests its evolutionary descent from an ancient icosahedral ancestor.     

Characterization of oil bodies in jelly fig achenes.

Thin-layer chromatography analysis revealed that the contents stored in oil bodies isolated from jelly fig (Ficus awkeotsang Makino) achenes were mainly neutral lipids (>90% triacylglycerols and approximately 5% diacylglycerols). Fatty acids released from the neutral lipids of achene oil bodies were highly unsaturated (62.65% alpha-linolenic acid, 18.24% linoleic acid, and 10.62% oleic acid). The integrity of isolated oil bodies was presumably maintained via electronegative repulsion and steric hindrance provided by their surface proteins. Immunological cross-recognition using antibodies against sesame oil-body proteins indicated that two oleosin isoforms and one caleosin were present in these oil bodies. MALDI-MS analyses confirmed that the three full-length cDNA fragments obtained by PCR cloning from maturing achenes encoded the two jelly fig oleosin isoforms and one caleosin identified by immunological screening.     

Proteoglycans of Wharton's jelly

Wharton's jelly (WJ) is a myxomatous substance surrounding the blood vessels of the umbilical cord. Proteoglycans (PGs) of Wharton's jelly have not been studied to date therefore it was decided to explore proteoglycan composition of this tissue. Proteoglycans were subjected to dissociative extraction with 4M guanidine hydrochloride containing Triton X-100 and protease inhibitors, purified by Q-Sepharose anion-exchange chromatography and lyophilised. They were analysed by gel filtration and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) before and after treatment with chondroitinase ABC. It was found that 1g of Wharton's jelly contains 2.43+/-0.63mg (n=10) of sulphated glycosaminoglycans (GAGs), reflecting the presence of proteoglycans. The proteoglycans were mainly substituted with chondroitin/dermatan sulphate (DS) chains. The predominant proteoglycan fraction included small proteoglycans with core proteins of 45 and 47kD, immunologically related to decorin (45 and 47kD) and biglycan (45kD). The expression of decorin core proteins was much higher than that of biglycan. Larger proteoglycans (core proteins of 90, 110, 220 and 260kD) were found in lower amounts. The most abundant of them (core protein of 260kD) was immunologically related to versican. Perlecan was not identified in Wharton's jelly. The study shows that Wharton's jelly contains mainly small chondroitin/dermatan sulphate proteoglycans, with decorin strongly predominating over biglycan. We suggest that an intensive expression of decorin is associated with very high content of its ligand, collagen.     

Antibacterial activity of major royal jelly proteins of the honeybee (Apis mellifera) royal jelly

Major royal jelly proteins (MRJPs) are the protein components in royal jelly (RJ). MRJPs 1–7 are detected in the honeybee Apis mellifera RJ. Although A. mellifera MRJP (AmMRJP) 2 exhibited antibacterial activity, the other MRJPs with antimicrobial activities in A. mellifera RJ remains largely unknown. Here, we compared the antibacterial activity of recombinant AmMRJPs 1–7 expressed in baculovirus-infected insect cells. Antibacterial assays of recombinant AmMRJPs 1–7 against the gram-negative bacterium Escherichia coli revealed that AmMRJPs 2–5 and 7 exhibited antibacterial activity, whereas AmMRJPs 1 and 6 displayed almost no antibacterial activity. Consistent with the antibacterial activity of AmMRJPs, AmMRJPs 2–5 and 7 are bound to bacterial cell walls. These results indicated that AmMRJPs 2–5 and 7 contribute directly to the antibacterial property of RJ, suggesting that MRJPs play a role in the antimicrobial property of RJ.     

Rotifers,the jelly plankton of freshwater

Jelly plankton (gelata) is a rather fuzzy concept that I attempt to redefine and expand: gelata should have no exo or endoskeleton, have a water content of 92–98%, and should usually be somewhat transparent. Although gelata are usually considered as part of the plankton, there are many cases in which they lead a benthic life, permanently or during part of their life. Gelatinous material can be part of the body, or can be secreted to form a sheath around it, especially in freshwater. Size is not a criterion: gelata individuals or colonies can be from 50 μm to 30 m and more in size. Early development stages (eggs and embryos) shed freely in the environment are not considered true gelata, even if enveloped in jelly. Under these conditions, jelly plankton in freshwater is represented by 20–40 species of cnidarians, by a few rhabdocoelid flatworms, and by up to 200 rotifer species (600+ if the periphytic and benthic species are included, and almost 1,500 species if males are included). Contrary to the ocean, where overfishing will benefit gelata, overfishing in freshwater will favor planktonic crustaceans, and these, in turn competitively suppress rotifers. Guest editors: S. S. S. Sarma, R. D. Gulati, R. L. Wallace, S. Nandini, H. J. Dumont and R. Rico-Martínez Advances in Rotifer Research     

蜂王浆蛋白生物学功能的研究

蜂王浆是哺育蜂咽下腺与上颚腺分泌的供3日龄以内蜜蜂幼虫和蜂王食用的浆状物质,具有多种生物活性。王浆含有丰富的蛋白质,通过直接分离纯化王浆中的蛋白质分子,或通过王浆蛋白基因克隆表达以获得表达产物,进而研究王浆蛋白的功能。研究发现王浆中含有多种具有特定功能的蛋白质,如MRJP3具有免疫调节作用,Jelleine-I-IV及Royalisin具有抗菌作用,MRJP1具有抗肿瘤功能及可能的蜜蜂行为调节功能,57kDa蛋白及Apisimin的促细胞生长功能,57kDa蛋白具有抗疲劳功能等。随着王浆蛋白组分分离、基因克隆表达及其功能研究的深入,王浆蛋白将被应用到生物医药、细胞培养、组织工程等更多的研究领域。     

Cardiac jelly arrangement during the formation of the tubular heart of the chick embryo.

The hearts of chick embryos from stages 9 to 11 according to Hamburger and Hamilton are studied by means of the electron microscopy, and the arrangement of the cardiac jelly (CJ) during the different steps of the fusion of the paired heart anlage is described. It is shown that two different areas can be distinguished in CJ: the CJ located between the endocardium and the myocardium (MECJ) and the CJ located between the endocardium and the ventral foregut endoderm (EECJ). MECJ is a zone poor on ultrastructural components most of which are unbanded filamentous material and low-density amorphous material, and its arrangement remains constant during the whole fusion process; EECJ, on the contrary, is very rich in ultrastructural components containing greater amounts of high-density amorphous material, collagen fibrils and cellular, detritus, and the arragement of this area of the CJ undergoes changes during the different fusion steps. Alcian blue staining does not show difference between both areas of CJ. It is suggested that the CJ can play a role during the fusion of the heart. In addition, some observations are reported which suggest that all the epithelial tissues surrounding the CJ can take part in the elaboration of that extracellular material.     

Distribution of lectin binding sites in Xenopus laevis egg jelly.

Eggs from the anuran Xenopus laevis are surrounded by a thick jelly coat that is required during fertilization. The jelly coat contains three morphologically distinct layers, designated J1, J2, and J3. We examined the lectin binding properties of the individual jelly coat layers as a step in identifying jelly glycoproteins that may be essential in fertilization. The reactivity of 31 lectins with isolated jelly coat layers was examined with enzyme-linked lectin-assays (ELLAs). Using ELLA we found that most of the lectins tested showed some reactivity to all three jelly layers; however, two lectins showed jelly layer selectivity. The lectin Maackia amurensis (MAA) reacted only with J1 and J2, while the lectin Trichosanthes kirilowii (TKA) reacted only with J2 and J3. Some lectins were localized in the jelly coat using confocal microscopy, which revealed substantial heterogeneity in lectin binding site distribution among and within jelly coat layers. Wheat germ agglutinin (WGA) bound only to the outermost region of J3 and produced a thin, but very intense, band of fluorescence at the J1/J2 interface while the remainder of J2 stained lightly. The lectin MAA produced an intense fluorescence-staining pattern only at the J1/J2 interface. Several lectins were also tested for the ability to inhibit fertilization. WGA, MAA, and concanavalin A significantly inhibited fertilization and WGA was found to block fertilization by preventing sperm from penetrating the jelly. Using Western blotting, we identified high-molecular-weight components in J1 and J2 that may be important in fertilization.     

Antioxidant capacity of major royal jelly proteins of honeybee (Apis mellifera) royal jelly

Major royal jelly proteins (MRJPs) of honeybee royal jelly (RJ) exhibit antimicrobial and antioxidant activities. Although MRJPs of Apis mellifera RJ (AmMRJPs) responsible for antibacterial activity have been identified, AmMRJPs with antioxidant effects remain to be elucidated. Here we identified and compared the antioxidant activities of purified recombinant AmMRJPs 1–7, which are expressed in baculovirus-infected insect cells. Antioxidant assays of recombinant AmMRJPs 1–7 against H₂O₂ revealed that AmMRJPs reduce caspase-3 activity and oxidative stress-induced cell apoptosis and lead to increased cell viability. Consistent with these results, AmMRJPs 1–7 exhibit 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity and protect against oxidative DNA damage. These results indicate that AmMRJPs play a role as antioxidants in A. mellifera RJ.     

Hyaluronan content of Wharton's jelly in healthy and Down syndrome fetuses.

The mechanisms by which the excess genetic material of chromosome 21 results in the dysmorphologic features of Down syndrome (DS) are largely unknown. It has been found that the extracellular matrix of nuchal skin of DS fetuses exhibits an higher content of hyaluronan (HA) compared to that of euploid fetuses. Since HA plays a central role in many morphogenetic processes during embryogenesis, an alteration in its metabolism could be involved in the pathogenesis of several structural defects of DS. The extracellular matrix of umbilical cord (UC) is the mammalian tissue with one of the highest content of HA. Therefore we sought to explore the quantitative HA modifications during gestation, tissue distribution and HA metabolism in euploid and DS UCs. Euploid UCs (n=28) and UCs from DS fetuses (n=13) were obtained after termination of pregnancy, spontaneous abortion, or at delivery. Quantitative and molecular size analysis were performed using HPLC and FPLC. Tissue distribution was visualized by immunohistochemistry. Gene expression for HA synthases (HAS) and hyaluronidases (HYAL) were quantified by real-time PCR techniques and HYAL activity was detected by zymography. In euploid UC only HA of a molecular weight of 1700 kDA was present while in DS UC an additional lower weight HA molecule of 1100 kDA was found. Immunohistochemistry showed a larger amount of Wharton's jelly HA in DS UCs than in euploid UC. Real-time PCR analysis showed that HAS 2 and HYAL 2 were expressed at significant levels in all specimens. A higher expression of HAS 2 and a lower expression of HYAL 2 was found in the Wharton's jelly of DS fetuses compared to that of euploid fetuses at 14 weeks of gestation. On the contrary, at term HYAL 2 expression was higher in DS specimens than in those from euploid fetuses. Zymographic studies showed a similar behavior with a lower HYAL activity at early gestation and a higher HYAL activity at term gestation in DS UCs compared to euploid specimens. Therefore we can conclude that HA is more represented in DS UCs than in euploid UCs. A complex alteration of the HA metabolism characterized by an increased synthesis of lower weight HA molecules is a peculiarity of DS UCs.     

Hydrophilic interaction chromatography/tandem mass spectrometry for the determination of melamine in royal jelly and royal jelly lyophilized powder

Melamine has become the focus of attention for the possible occurrence of nephrolithiasis and associated deaths, because it was added to foods to increase the apparent protein content by unethical manufacturers. An analytical method based on hydrophilic interaction chromatography/tandem mass spectrometry (HILIC-MS/MS) was developed and validated for the determination of melamine in the royal jelly (RJ) and royal jelly lyophilized powder (RJLP). Trace of melamine was extracted from the RJ and RJLP by ultrasonic-assisted extraction followed by clean-up procedure using mixed-mode cation exchange (MCX) solid phase extraction and separated on a hydrophilic interaction chromatography (HILIC) analytical column with acetonitrile/5 mM ammonium acetate buffer (88:12, v/v) as mobile phase. Detection was carried out by positive electrospray ionization (ESI+) in multiple reaction monitoring (MRM) mode. The chromatographic separation was obtained within 5 min and was linear in the concentration range of 0.01–8 μg/mL in RJ and 0.05–10 μg/mL in RJLP for melamine. The mean extraction recoveries for melamine were ranged from 89.6 to 100.4%. Method validation parameters were evaluated such as linearity, selectivity, precision, carryover and recovery, giving results within the acceptable range. The proposed method was successfully applied to the quantitation of melamine in RJ and RJLP. This approach will be of particular utility for the evaluation of melamine residue level and routine monitor of melamine in RJ and RJLP samples.