Subnanomolar concentrations of membrane chitolipooligosaccharides from Rhizobium leguminosarum biovar trifolii are fully capable of eliciting symbiosis-related responses on white clover

Axenic seedling bioassays were performed on white clover, vetch, and alfalfa to assess the variety and dose responses of biological activities exhibited by membrane chitolipooligosaccharides (CLOSs) from wild type Rhizobium leguminosarum bv. trifolii ANU843. Subnanomolar concentrations of CLOSs induced deformation of root hairs (Had) and increased the number of foci of cortical cell divisions (Ccd) in white clover, some of which developed into nodule meristems. In contrast, ANU843 CLOSs were unable to induce Had in alfalfa and required a 10⁴-fold higher threshold concentration to induce this response in vetch. Also, ANU843 CLOSs were not mitogenic on either of these non-host legumes. In addition, CLOS action also increased chitinase activity in white clover root exudate. Thus, the membrane CLOSs from wild type R. leguminosarum bv. trifolii are fully capable of eliciting various symbiosis-related responses in white clover in the same concentration range as extracellular CLOSs of other rhizobia on their respective legume hosts. These results and our earlier studies indicate that membrane CLOSs represent one of many different classes of bioactive metabolites made by R. leguminosarum bv. trifolii which elicit more intense symbiosis-related responses in white clover than in other legumes. Therefore, CLOSs evidently play an important role in symbiotic development, but they may not be the sole determinant of host-range in the Rhizobium-clover symbiosis.Abbreviations Ccd cortical cell division - CLOS chitolipooligosaccharide - Had root hair deformation     

Vascular endothelial cells: Targets for studying the activity of hair follicle cell-produced VEGF

Fetal bovine aortic endothelial cells (FBAEC) were exposed to purified fractions of conditioned medium from cultures of hair dermal papilla cells (DPC) to determine the existence of any vascular endothelial growth factor (VEGF)-like paracrine activity of the latter. Such fractions were tested for stimulation of growth and migration of cultured FBAEC. In addition, VEGF secretion by DPC was measured by radioassay of VEGF receptors using FBAEC as target cells. The results showed that stimulation of FBAEC proliferation and migration following exposure to purified conditioned medium was dose-dependent. Radioreceptor assays of recombinant VEGF and purified DPC-conditioned medium showed competitive VEGF binding in FBAEC.Abbreviations CM conditioned medium - DMEM Dulbecco's modified eagle's medium - DPC dermal papilla cells - EDTA ethylenediaminetetra-acetic acid - FBAEC fetal bovine aortic endothelial cells - FCS fetal calf serum - VEGF vascular endothelial growth factor     

A novel human type I hair keratin gene: evidence for two keratin hHa3 isoforms

We present the nucleotide and amino acid sequence for a novel human type I hair keratin, which could be identified through its high sequence homology and strict carboxyterminal length identity as a human ortholog of the murine hair keratin mHa3. Our hHa3 sequence differs, however, from that of a previously described hHa3 hair keratin (published only as an amino acid sequence; [13]) in 24 amino acid positions, 8 of which occur in the middle of the carboxyterminal domain. PCR of genomic DNA from 25 normal human subjects using a primer pair derived from sequence segments located in the 3-region of our hHa3 clone that encode conserved amino acid sequences in both keratins, resulted in the amplification of two distinct products of 0.38 kbp and 1.0 kbp. DNA sequence analysis of the cloned PCR products allowed identification of the 0.38 kb sequence as that originating from Yuet al. [13] and the 1.0 kb sequence as that being derived from our data. The difference in fragment length was due to unique intron 6 sequences, indicating that these two keratin species are encoded by genes of their own. Moreover, extensive Southern blot analyses with DNA from 25 unrelated individuals of different races using a 3-noncoding sequence from our keratin and the intron 6 sequence of the keratin of Yuet al. [13], as hybridization probes showed that both keratin genes are present as single copy sequences occurring ubiquitously and without gross alterations in the human genome. Collectively, these data demonstrate that the human type I hair keratin described in this paper represents an isoform of the previously described hHa3 keratin. We propose that these hHa3 isoforms be named in chronological order of discovery hHa3-I and hHa3-II.     

Vanadium levels in urine and cystine levels in fingernails and hair of exposed and normal persons

Vanadium was determined by radiochemical neutron activation analysis (RNAA) with proven accuracy in urine of workers occupationally exposed to vanadium-rich dust in a vanadium pentoxide production plant, and values in the range of 3.02–762 ng/mL (median 33.0 ng/mL) were found. In a control group consisting of administrative workers of the plant, urinary vanadium levels were found in the range of 1.05–53.4 ng/mL (median 2.53 ng/mL), whereas in an another control group of occupationally nonexposed persons, these values amounted to 0.066–0.489 ng/mL (median 0.212 ng/mL). Accuracy of the results was tested by analysis of reference material IAEA A-13 Animal Blood and NIST SRM-1515 Apple Leaves, and very good agreement was found with literature and the NIST certified values, respectively. Unlike urine, no significant differences were found for cystine levels in fingernails and hair of exposed and control persons.     

Growth response and phosphorus uptake of rye with long and short root hairs: Interactions with mycorrhizal infection

Plant growth and phosphorus (P) uptake of two selections of rye (Secale cereale L.) differing in length of root hairs, in response to mycorrhizal infection were investigated. Rye plants with short root hairs (SRH) had a greater length of root infected by Glomus intraradices (up to 32 m pot^–1) than those with long root hairs (LRH) (up to 10 m pot^–1). Application of P decreased the percentage of root length infected in both selections. In low-P soil, mycorrhizal infection increased shoot and root P concentration, especially in LRH plants. Generally, LRH had higher shoot dry weight than SRH plants. P uptake was increased both by LRH and by mycorrhizal infection. Differences in specific P uptake and P utilization efficiency between SRH and LRH plants were observed in non-mycorrhizal plants. With low P supply, P utilization efficiency (dry matter yield per unit of P taken up) of LRH plants increased with time. However, mycorrhizal infection reduced P utilization efficiency, particularly of SRH plants. SRH plants, which were agronomically less efficient (i.e. low dry matter yield at low P supply) were more responsive to either mycorrhizal infection or P addition than the LRH plants. No interaction was observed between mycorrhizal infection and root hair length.     

Electromotility of outer hair cells from the cochlea of the echolocating bat,Carollia perspicillata

Isolated outer hair cells (OHCs) and explants ot the organ of Corti were obtained from the cochlea of the echolocating bat, Carollia perspicillata, whose hearing range extends up to about 100 kHz. The OHCs were about 10–30 m long and produced resting potentials between-30 to -69 mV. During stimulation with a sinusoidal extracellular voltage field (voltage gradient of 2 mV/m) cyclic length changes were observed in isolated OHCs. The displacements were most prominent at the level of the cell nucleus and the cuticular plate. In the organ of Corti explants, the extracellular electric field induced a radial movement of the cuticular plate which was observed using video subtraction and photodiode techniques. Maximum displacements of about 0.3–0.8 m were elicited by stimulus frequencies below 100 Hz. The displacement amplitude decreased towards the noise level of about 10–30 nm for stimulus frequencies between 100–500 Hz, both in apical and basal explants. This compares well with data from the guinea pig, where OHC motility induced by extracellular electrical stimulation exhibits a low pass characteristic with a corner frequency below 1 kHz. The data indicate that fast OHC movements presumably are quite small at ultrasonic frequencies and it remains to be solved how they participate in amplifying and sharpening cochlear responses in vivo.Abbreviations BM basilar membrane - FFT fast Fourier Transfer - IHC inner hair cell - OHC outer hair cell     

Trace elements in hair of blackfoot disease

Blackfoot disease is a peripheral vascular disease resulting in gangrene of the lower extremities. Though extensive epidemiological study has implicated that high arsenic content in artesian well water of the endemic area, bears some important connection with the disease, the etiology of the disease is still unknown. In this study, attention is paid to multielement determination in order to find out whether the trace elements in hair of Blackfoot disease patients are different from those of the controls. Experimental results indicate that the concentrations of As and Se in hair of patients are significantly higher than those of the controls, but Ca and Zn are significantly lower than those of the controls. The possible connection of these elements with the etiology of the disease is discussed.     

Microscopic analysis of the effect ofRhizobium leguminosarum biovartrifolii host specific nodulation genes in the infection of white clovers

Summary A microscopic assessment is presented of the comparative infection capacity of wild-type and hybrid strains ofRhizobium leguminosarum bv.viciae withR. l. bv.trifolii strain ANU 843 on white clover seedlings. TheR. l. bv.viciae hybrid strains contained defined DNA segments coding for different combinations ofR. l. bv.trifolii host-specific nodulation genes. White clover plants were examined over a 72 h period to assessRhizobium infectivity, the morphological changes in root hair growth; colonisation ability of rhizobia; infection thread initiation and the ability to induce cortical cell division.R. l. bv.viciae strain 300 induced root hair curling more slowly than strain ANU 843 or any of the hybrid strain 300 bacteria, and when curling had taken place, there was poorer colonization by strain 300 within the folded hair cell, no evidence of infection thread formation and only limited cortical cell division 72 h after inoculation. The addition of the host-specific nodulation genes ofR. l. bv.trifolii to strain 300 was necessary to induce infection threads and establish a normal pattern of nodulation of the roots of white clovers.     

A Method for Determining the Activity State of Hair Follicles

A histological method is described for determining the proportion of growing hair follicles h skin samples. A variation of the Sacpic staining method, modified for bulk processing, produces high contrast staining of the principal tissue types present in skin. In particular, the inner root sheath is accentuated, facilitating detection of active follicles. Skin preparations from a range of species are used to illustrate structural characteristics of follicles viewed in cross section at various stages of the hair cycle and to establish criteria for classification of the state of activity of follicles. The hair cycle may be divided into quiescent and active states at the points of rapid transition (early pronanagen and mid catagen). Data from repeated skin biopsies from ferrets and goats are also used to demonstrate quantitative estimation of follicle activity, change in compound follicle size, and the relationship between follicle type and fiber medullation.     

Impacts of iron on phosphate starvation-induced root hair growth in Arabidopsis

In Arabidopsis, phosphate starvation (-Pi)-induced responses of primary root and lateral root growth are documented to be correlated with ambient iron (Fe) status. However, whether and how Fe participates in -Pi-induced root hair growth (RHG) remains unclear. Here, responses of RHG to different Fe concentrations under Pi sufficiency/deficiency were verified. Generally, distinct dosage effects of Fe on RHG appeared at both Pi levels, due to the generation of reactive oxygen species. Following analyses using auxin mutants and the phr1 mutant revealed that auxin and the central regulator PHR1 are required for Fe-triggered RHG under −Pi. A further proteomic study indicated that processes of vesicle trafficking and auxin synthesis and transport were affected by Fe under −Pi, which were subsequently validated by using a vesicle trafficking inhibitor, brefeldin A, and an auxin reporter, R2D2. Moreover, vesicle trafficking-mediated recycling of PIN2, an auxin efflux transporter, was notably affected by Fe under -Pi. Correspondingly, root hairs of pin2 mutant displayed attenuated responses to Fe under -Pi. Together, we propose that Fe affects auxin signalling probably by modulating vesicle trafficking, chiefly the PIN2 recycling, which might work jointly with PHR1 on modulating -Pi-induced RHG.