Fluctuations in human serum lipoproteins during the normal menstrual cycle

1. Lipoproteins were measured in sera from 11 young women having a similar environment and diet. Sera were obtained at weekly intervals over a 12-week period. The values of the lipoproteins during periods in the normal ovulatory cycle were compared to assess their relation to reported hormone concentrations in blood. 2. Only the 4–0s_f (HDL₂) (d 1·125 sodium chloride) fraction changed significantly; it increased at ovulation in ten of the 11 subjects and fell as menstruation approached. 3. There was greater variability in most of the low-density rather than the high-density lipoproteins within individuals. The lipoprotein class most characteristic for an individual was the 4–0s_f or HDL₂ fraction.     

Apolar conjugates of ecdysteroids are not used as a storage form of molting hormone in the argasid tick Ornithodoros moubata

Fifth (last) instar nymphs of th e tick Ornithodoros moubata convert ingested 20-hydroxyecdysone (20E) to apolar conjugates AP2, which are then converted to th e more polar conjugates API. Only small quantities of free hormone were transferred to th e hemolymph and the carcass within t h e first 2 days after the blood meal. The proportion of radiolabel in these two compartments was highest at the time of the endogenous ecdysteroid peak; however, no traces of free [³H]20E were detected. The conversion probably occurs principally in the intestinal cells. Eleven days after ingestion, 84% of the radiolabel is located in the digestive tract, mainly in the form of API conjugates. API obtained in second instar nymphs fed with [3H]ecdysone ([³H]E) remain stable throughout the following nymphal instars. The ecdysteroid moiety of APT remained unchanged. The hydrolysis, although not complete, always yielded a peak comigrating with the reference E but never 20E or any other clearly distinct peaks that may have corresponded to metabolites of 20E. Less label per individual was present in adults, but its nature remained the same, viz., API mainly located in the digestive tract. In females, 2.5% of the label was transferred to the progeny during the first ovipositional cycle. Apolar products (mainly AP2) that accumulated in eggs of females injected with [³H]E or [³H]20E during vitellogenesis remained unchanged during the whole embryonic development. During the molting cycle of larvae, there was only a slight conversion of AP2 to API, but esterase hydrolysis of these products released the same percentages of E and 20E as in the freshly laid eggs. We conclude that in this tick species apolar conjugates of ecdysteroids are inactivation metabolites that are not reutilized during the development of the animal. These metabolites are mainly retained in the tick, probably because of its peculiar blocked midgut. Several studies have shown that in other arthropod species (ticks, spiders, and insects), these apolar metabolites are excreted in the feces.     

Amino acid sequences of stomach and nonstomach lysozymes of ruminants

Summary Complete amino acid sequences are presented for lysozymesc from camel and goat stomachs and compared to sequences of other lysozymesc. Tree analysis suggests that the rate of amino acid replacement went up as soon as lysozyme was recruited for the stomach function in early ruminants. The two lysozymes from goat stomach are the products of a gene duplication that probably took place before the divergence of cow, goat, and deer about 25 million years ago. Partial sequences of three lysozymes from goat tears indicated that (a) the goat tear family of lysozymes may have diverged from the stomach lysozyme family by an ancient duplication and (b) later duplications are probably responsible for the multiple forms of tear and milk lysozymes in ruminants.     

Relationship of indole-3-butyric acid and adventitious rooting in M.26 apple (Malus Pumila mill.) shoots cultured in vitro

The role of indole-3-butyric acid (IBA) in adventitious root formation was studied by analyzing the uptake and subsequent metabolism of IBA in shoots of M.26 apple (Malus pumila Mill.) rootstock grown in vitro. Roots were induced by exposing shoots to 4 M IBA and [³H]IBA for 5 days in the dark and then transferring them to plant growth regulator (PGR)-free medium in the light until roots formed. Approximately 50% of the total radioactivity applied was taken up from the agar medium by the shoots during the 5-day incubation period in IBA. Indole-3-butyric acid metabolism was studied by extraction and high-performance liquid chromatographic (HPLC) separation of [³H]IBA and metabolites from the basal sections of treated shoots. The major [³H]IBA metabolite co-eluted with authentic [¹⁴C]indole-3-acetic acid (IAA) suggesting that IBA was converted to IAA in the shoots. The proportion of newly synthesized IAA present as conjugates was higher at the end of the 5-day IBA treatment period than after 13 days in PGR-free medium. There appeared to be no conjugation of IBA at any time.     

Mechanisms of Injury-Induced Calcium Entry into Peripheral Nerve Myelinated Axons: Role of Reverse Sodium-Calcium Exchange

Abstract: To investigate the route of axonal Ca²⁺ entry during anoxia, electron probe x-ray microanalysis was used to measure elemental composition of anoxic tibial nerve myelinated axons after in vitro experimental procedures that modify transaxolemmal Na⁺ and Ca²⁺ movements. Perfusion of nerve segments with zero-Na⁺/Li⁺-substituted medium and Na⁺ channel blockade by tetrodotoxin (1 µM) prevented anoxia-induced increases in Na and Ca concentrations of axoplasm and mitochondria. Incubation with a zero-Ca²⁺/EGTA perfusate impeded axonal and mitochondrial Ca accumulation during anoxia but did not affect characteristic Na and K responses. Inhibition of Na⁺-Ca²⁺ exchange with bepridil (50 µM) reduced significantly the Ca content of anoxic axons although mitochondrial Ca remained at anoxic levels. Nifedipine (10 µM), an L-type Ca²⁺ channel blocker, did not alter anoxia-induced changes in axonal Na, Ca, and K. Exposure of normoxic control nerves to tetrodotoxin, bepridil, or nifedipine did not affect axonal elemental composition, whereas both zero-Ca²⁺ and zero-Na⁺ solutions altered normal elemental content characteristically and significantly. The findings of this study suggest that during anoxia, Na⁺ enters axons via voltage-gated Na⁺ channels and that subsequent increases in axoplasmic Na⁺ are coupled functionally to extraaxonal Ca²⁺ import. Intracellular Na⁺-dependent, extraaxonal Ca²⁺ entry is consistent with reverse operation of the axolemmal Na⁺-Ca²⁺ exchanger, and we suggest that this mode of Ca²⁺ influx plays a general role in peripheral nerve axon injury.     

Monoclonal antibodies against human immunodeficiency virus type 1 integrase: epitope mapping and differential effects on integrase activities in vitro.

Human immunodeficiency virus type 1 (HIV-1) integrase (IN) catalyzes the integration of viral DNA into the host chromosome, an essential step in retroviral replication. As a tool to study the structure and function of this enzyme, monoclonal antibodies (MAbs) against HIV-1 IN were produced. Epitope mapping demonstrated that the 17 MAbs obtained could be divided into seven different groups, and the selection of MAbs representing these groups were tested for their effect on in vitro activities of IN. Four groups of MAbs recognized epitopes within the region of amino acids (aa) 1 to 16, 17 to 38, or 42 to 55 in and around the conserved HHCC motif near the N terminus of IN. MAbs binding to these epitopes inhibited end processing and DNA joining and either stimulated or had little effect on disintegration and reintegration activities of IN. Two MAbs binding to epitopes within the region of aa 56 to 102 in the central core or aa 186 to 250 in the C-terminal half of the protein showed only minor effects on the in vitro activities of IN. Three Mabs which recognized on epitope within the region of aa262 to 271 of HIV-1 IN cross-reacted with HIV-2 IN. MAbs binding to this epitope clearly inhibited end processing and DNA joining and stimulated or had little effect on disintegration. In contrast to the N-terminal-specific MAbs, these C-terminal-specific MAbs abolished reintegration activity of IN.     

Duplication of the PMP22 gene in 17p partial trisomy patients with Charcot-Marie-Tooth type-1A neuropathy

Autosomal dominant Charcot-Marie-Tooth type-1A neuropathy (CMT1A) is a demyelinating peripheral nerve disorder that is commonly associated with a submicroscopic tandem DNA duplication of a 1.5-Mb region of 17p11.2p12 that contains the peripheral myelin gene PMP22. Clinical features of CMT1A include progressive distal muscle atrophy and weakness, foot and hand deformities, gait abnormalities, absent reflexes, and the completely penetrant electrophysiologic phenotype of symmetric reductions in motor nerve conduction velocities (NCVs). Molecular and fluorescence in situ hybridization (FISH) analyses were performed to determine the duplication status of the PMP22 gene in four patients with rare cytogenetic duplications of 17p. Neuropathologic features of CMT1A were seen in two of these four patients, in addition to the complex phenotype associated with 17p partial trisomy. Our findings show that the CMT1A phenotype of reduced NCV is specifically associated with PMP22 gene duplication, thus providing further support for the PMP22 gene dosage mechanism for CMT1A. Received: 3 May 1995 / Revised: 1 August 1995     

Transformation efficiencies and progeny analysis after varying different parameters of direct gene transfer of Nicotiana tabacum protoplasts

Nicotiana tabacum protoplasts were transformed by polyethylene glycol (PEG)-mediated uptake and electroporation, with circular and linear DNA, and with or without X-ray irradiation. We investigated the influence on the transient expression by these parameters as well as on the frequencies for stable transformation. Plants were regenerated and selfed, and the progenies of the transformed plants were analysed and used to compare the pattern of gene integration by these different variations in transformation methods. The results from the transient expression as judged by glucuronidase (GUS) activity, showed electroporation to give higher and more reproducible results than PEG-mediated uptake. Using linear instead of circular DNA increased the rate of stable transformation about 3 times. Including a mild X-ray treatment gave an increase in the same range. When the inheritance of the transferred trait was investigated, it was found that protoplasts transformed with linear DNA resulted in the highest number of plants with single-copy insertions. Protoplasts transformed with circular DNA showed the highest incidence of losing the trait, while plants in which the transformation included an X-ray treatment, had the highest frequency of multicopy insertion events.     

In vitro testing of the biological activity ofRubia cordifolia leaves on primateStrongyloides species

ChimpanzeesPan troglodytes in Kibale National Park, Uganda occasionally swallow entire leaves ofRubia cordifolia (Rubiaceae) without chewing them. The leaves are subsequently egested with minimal damage and no sign of any significant digestion. Similar behavior reported elsewhere has been proposed to have medicinal effects. Here we test the hypothesis that chemical components in swallowed leaves have negative effects on intestinal nematodes. We used anin vitro assay to detect the effects of methanol extracts ofR. cordifolia leaves on nematodes,Strongyloides spp., cultured from feces. Control extracts were distilled water, methanol solution, and methanol extracts of food items that were chewed, rather than swallowed, by chimpanzees. Effects of experimental or control solutions were assayed by nematode motility. There was no difference in nematode motility among control and experimental extracts. This study therefore did not support the hypothesis of pharmacological self-medication via leaf swallowing.