The Olduvai Hominid 8 foot: Adult or subadult?

Olduvai Hominid 8 (OH 8), an articulating set of fossil hominin tarsal and metatarsal bones, is critical to interpretations of the evolution of hominin pedal morphology and bipedal locomotion. It has been suggested that OH 8 may represent the foot of a subadult and may be associated with the OH 7 mandible, the type specimen of Homo habilis. This assertion is based on the presence of what may be unfused distal metatarsal epiphyses. Accurately assessing the skeletal maturity of the OH 8 foot is important for interpretations of the functional morphology and locomotor behavior of Plio-Pleistocene hominins. In this study, we compare metatarsal fusion patterns and internal bone morphology of the lateral metatarsals among subadult hominines (85 modern humans, 48 Pan, and 25 Gorilla) to assess the likelihood that OH 8 belonged to either an adult or subadult hominin. Our results suggest that if OH 8 is indeed from a subadult, then it displays a metatarsal developmental pattern that is unobserved in our comparative sample. In OH 8, the fully fused base of the first metatarsal and the presence of trabecular bone at the distal ends of the second and third metatarsal shafts make it highly improbable that it belonged to a subadult, let alone a subadult that matches the developmental age of the OH 7 mandible. In total, the results of this study suggest that the OH 8 foot most likely belonged to an adult hominin.     

Crocodylian and mammalian carnivore feeding traces on hominid fossils from FLK 22 and FLK NN 3, Plio-Pleistocene, Olduvai Gorge, Tanzania

Taphonomic analysis of the Olduvai Hominid (OH) 8 left foot from FLK NN Level 3 and the OH 35 left leg from FLK Level 22 (Zinjanthropus level) in Middle Bed I, Olduvai Gorge, indicates that both were fed upon by crocodiles. Both bear extensive tooth marking, including bisected tooth marks diagnostic of crocodylian feeding. The location of the bisected tooth marks on the distal tibia and the talus indicates disarticulation of the foot by crocodiles. The broken proximal ends of the tibia and fibula are more typical of feeding by a leopard-like carnivore, as is damage to the OH 7 mandible and parietals that are associated with and may derive from the same individual as OH 8. Previous work showing a close articulation of the foot and the leg has been used to suggest that the two specimens belong to the same individual despite deriving from sites separated by 200 m and slightly different stratigraphic levels according to previous work. The location and agent of tooth marking and the nature of gross damage do not refute this hypothesis, but the punctures on the talus and distal tibia differ in size and sharpness. Recent work shows that the stratigraphic discrepancy between OH 8 and OH 35 is greater than previously thought, refuting the single-individual hypothesis. Although seemingly unlikely, this denotes that two hominids represented by rarely found leg and foot elements both lost their left foot to crocodiles at nearby sites within a 6,000 year interval. We cannot determine if the hominids were preyed upon by crocodiles or mammalian carnivores. However, the carnivore damage to them and associated faunal remains suggests that high predation risk constrained hominid activities involving discard of the stone artifacts found at these sites. This finding is inconsistent with the interpretation of the sites as home bases or living floors.     

Modification of yttrium alkoxides: β-Ketoesterate-substituted yttrium alkoxo/hydroxo/oxo clusters

Reaction of Y₅O(OiPr)₁₃ (“yttrium iso-propoxide”) with one molar equivalent of isopropyl acetoacetate (iprac) per Y resulted in the formation of Y₉O(OH)₉(OiPr)₈(iprac)₈, a rare example of an yttrium alkoxo/hydroxo/oxo cluster. Reaction in a 1:3 molar ratio gave Y₄(OH)₂(iprac)₁₀ and Y₆(OH)₆(iprac)₁₂ instead. A fourth cluster, Y₉O(OH)₉(iprac)₁₆, structurally closely related to Y₉O(OH)₉(OiPr)₈(iprac)₈, was obtained upon recrystallization of Y₄(OH)₂(iprac)₁₀ from CDCl₃.     

Metatarsal fusion pattern and developmental morphology of the Olduvai Hominid 8 foot: Evidence of adolescence

The morphology of the Olduvai Hominid (OH) 8 foot and the sequence of metatarsal epiphyseal fusion in modern humans and chimpanzees support the hypothesis that OH 8 belonged to an individual of approximately the same relative age as the OH 7 subadult, the holotype of Homo habilis. Modern humans and chimpanzees exhibit a variety of metatarsal epiphyseal fusion patterns, including one identical to that observed in OH 8 in which metatarsal 1 fuses before metatarsals 2-5. More than the metatarsal fusion sequence, however, the principal evidence of the youthful age of OH 8 lies in the morphology of metatarsals 1, 2, and 3. Because both OH 8 and OH 7 come from the same stratum at the FLK NN type site, the most parsimonious explanation of the OH 8 and OH 7 data is that this material belonged to the same individual, as originally proposed by Louis Leakey. The proposition that OH 8 belonged to an adult is unsupported by morphology, including radiographic evidence, and the fusion sequences in human and chimpanzee skeletal material reported here and in the literature.     

FT-IR study of some seco- and apocarotenoids

FT-IR spectroscopy was applied to investigate 15 different carotenoids. The following compounds were examined: beta-carotenone (1); semi-beta-carotenon-epoxide (2); beta-apo-8'-carotenal (3); ethyl-beta-apo-8'-carotenoate (4); beta-citraurin (5); 5,6-Epoxy-beta-caroten-8'-al (6); beta-citraurin-epoxide (7); apo-10'-violaxanthal (8); persicaxanthin (9); capsylaldehyde (10); capsanthylal (11); retinol (12); retinal (13); retinoic acid (14); and bixin (15). Some characteristic functional groups (Cz.dbnd;C, Cz.dbnd;O, CHO, OH, etc.) were identified. We focused on the influence of conjugation of the keto-, aldehyde- and ester groups on the absorption of the Cz.dbnd;C bonds. This method is useful in the fast analysis of the biologically important carotenoids especially if there are small samples available.     

25(OH)D3 Affects the Maturation and Function of Mouse Bone Marrow-Derived Dendritic Cells Stimulated by Mycobacterium Bovis BCG

It has been shown that vitamin D deficiency increases an individual’s susceptibility to tuberculosis (TB). However, very little is known about the effect of vitamin D on the immune response to Mycobacterium tuberculosis (M. tb) in dendritic cells (DCs). Because DCs play an important role in TB infection, we investigated the phenotypic characteristics and functional capabilities of mouse bone marrow-derived dendritic cells (BMDCs) after stimulation with Bacillus Calmette-Guérin (BCG) in the presence or absence of 25(OH)D₃(100 nM). Bone marrow cells from mice were cultured with GM-CSF (20 ng/ml) and were then treated with 25(OH)D₃ for 7 days. On day 6, 5 µg/ml of BCG (≥1.0×10⁶ CFU/mg) was added to the cells for 24 hours, and on day 7, the non-adherent cells were harvested for phenotypic and functional analyses. After incubation with 25(OH)D₃, the expression levels of MHC-II and CD86 on the surface of the dendritic cells (DCs) and the ability of the DCs to stimulate proliferation of allogeneic mixed lymphocytes were lower than control cells (p<0.05). Furthermore, the level of Interleukin (IL) -4 secreted by the BMDCs in the 25(OH)D₃ culture was lower than that in the control culture (p<0.01). However, the BMDCs cultured with 25(OH)D₃ produced significantly higher levels of IL-2, IL-6, IL-10 and interferon gamma(IFN-γ) than those in the control culture (p<0.05). These findings suggest that 25(OH)D₃ modulates the immune response during mycobacterial infection by affecting the maturation and function of DCs.     

Olduvai Hominin 8 foot pathology: A comparative study attempting a differential diagnosis

Olduvai Hominin (OH) 8, a 1.76 million year old left foot skeleton, has osteophytic lipping on the metatarsal bases, which when compared to a modern sample, may help paleoanthropologists determine whether the foot bones represent an injured subadult or an osteoarthritic adult. This study compares the OH 8 lipping pattern to those of 140 individual Amerindians comprising four different age classes to determine whether the OH 8 lipping is likely to be age-related osteoarthritis. OH 8 metatarsal lipping followed a pattern similar to that determined in the comparative sample to be age-related osteoarthritis. Similarities include metatarsal base lipping that is frequently located on the dorsal surface, metatarsal base lipping that is more severe on the lateral metatarsals compared to the medial metatarsals, and the presence of a pseudojoint between metatarsal 1 and metatarsal 2. The chance of finding an individual with osteoarthritis lipping increases from 3.45% in the age group 18–22 years to 55% in individuals over 35 years. The chance of finding a pseudojoint increases from 1.32% in non-osteoarthritic individuals to 15.15% in individuals with osteoarthritis. Results from this study indicate that the OH 8 foot bones are most likely from an adult and more likely to belong to Paranthropus boisei, the skull of which was found in the same excavations with OH 8, than to the juvenile Homo habilis holotype.     

Association between 12α-hydroxylated bile acids and hepatic steatosis in rats fed a high-fat diet

High-fat (HF) diet induces hepatic steatosis that is a risk factor for noncommunicable diseases such as obesity, type 2 diabetes and cardiovascular disease. Previously, we found that HF feeding in rats increases the excretion of fecal bile acids (BAs), specifically 12α-hydroxylated (12αOH) BAs. Although the liver is the metabolic center in our body, the association between hepatic steatosis and 12αOH BAs in HF-fed rats is unclear. Thus, we investigated extensively BA composition in HF-fed rats and evaluated the association between hepatic steatosis and 12αOH BAs. Acclimated male inbred WKAH/HkmSlc rats were divided into two groups and fed either control or HF diet for 8 weeks. Feeding HF diet increased hepatic triglyceride and total cholesterol concentrations, which correlated positively with 12αOH BAs concentrations but not with non-12αOH BAs in the feces, portal plasma and liver. Accompanied by the increase in 12αOH BAs, the rats fed HF diet showed increased fat absorption and higher mRNA expression of liver Cidea. The enhancement of 12αOH BA secretion may contribute to hepatic steatosis by the promotion of dietary fat absorption and hepatic Cidea mRNA expression. The increase in 12αOH BAs was associated with enhanced liver cholesterol 7α-hydroxylase (Cyp7a1) and sterol 12α-hydroxylase (Cyp8b1) mRNA expression. There was a significant increase in 7α-hydroxycholesterol, a precursor of BAs, in the liver of HF-fed rats. Altogether, these data suggest that the HF diet increases preferentially 12αOH BAs synthesis by utilizing the accumulated hepatic cholesterol and enhancing mRNA expression of Cyp7a1 and Cyp8b1 in the liver.     

A re-evaluation of morphological characters of the invasive ascidian Corella eumyota reveals two different species at the tip of South America and in the South Shetland Islands, Antarctica

The native solitary ascidian Corella eumyota Traustedt, 1882) is commonly found in the Southern Hemisphere in the cold-temperate waters of the Subantarctic and Antarctic regions. Its recent spread into the Northern Hemisphere throughout the NE Atlantic gave the species the status of invasive. Together with its widespread distribution, reports on its wide variability (several distinct morphological characters, genetic discontinuities and also possible misidentifications) cast doubt on the taxonomic status of different populations of this species. This work, based on the observation, quantification and analysis of specific morphological characters in specimens collected at five different localities of South America and Antarctica, strongly indicates that there are two different species: C. eumyota from South America and Corella antarctica Sluiter, 1905) from Antarctica, which has been till now considered a junior synonym of the former. The species clearly differ in the arrangement of the gonadal ducts, the size of the larvae and the shape of the anus, among other characters. Morphological variation displays a defined, discrete grouping supporting a clear differentiation into two species. This result shows the need for careful inspection of specimens to avoid wrong interpretations in a context of changes of marine biota due to biological invasions.     

A Homo habilis maxilla and other newly-discovered hominid fossils from Olduvai Gorge, Tanzania

In 1995, a 1.8 million year old hominid maxilla with complete dentition (OH 65) was excavated from Bed I in the western part of Olduvai Gorge. The molar crowns are small relative to the long flaring roots, and the root of the canine is very long and straight. The broad maxilla with wide U-shaped palate and the form of the tooth roots closely match those of KNM-ER 1470 which, in its parietal size and morphology, matches the type specimen of Homo habilis, OH 7. Thus, OH 65 and KNM-ER 1470 group with OH 7 as representatives of H. habilis while some other Olduvai specimens, such as OH 13 and OH 24, have more in common in terms of morphology and brain size with Australopithecus africanus. Between 1995 and 2007, the OLAPP team has recovered teeth of eight other hominid individuals from various parts of Olduvai Gorge. These have been identified as belonging to H. habilis, Paranthropus boisei, and Australopithecus cf. africanus.     

Brief communication: evidence bearing on the status of Homo habilis at Olduvai Gorge

Students of the early hominin career have debated the status of Homo habilis since its discovery in 1960. Today discussion centers on which specimens should be included in the species and what constitutes the holotype. Recent reviews of early Homo suggest that the Olduvai Hominid 8 foot may sample Paranthropus while the OH 7 skull bones, mandible, and hand sample H. habilis. Moreover, some suggest that while H. habilis in Middle Bed I at Olduvai is craniodentally Homo-like, the postcranial skeleton of H. habilis is more like that of Australopithecus. Evidence presented here indicates not only that OH 7 and OH 8 represent H. habilis but also that they come from a single individual. The association of OH 35 with OH 7 and OH 8 is less certain. Morphological, pathological, and taphonomic evidence favors the inclusion of OH 35 in the holotype. However, stratigraphic evidence suggests that OH 35 and OH 8 are not coterminous. With or without OH 35, the holotype of H. habilis ranks as one of the most complete early hominin skeletons and the most complete and functionally informative specimen of early Homo.     

Serum 25-Hydroxyvitamin D Status and Longitudinal Changes in Weight and Waist Circumference: Influence of Genetic Predisposition to Adiposity

Studies of the relationship between serum 25-hydroxyvitamin D (25(OH)D) and changes in measures of adiposity have shown inconsistent results, and interaction with genetic predisposition to obesity has rarely been examined. We examined whether 25(OH)D was associated with subsequent annual changes in body weight (ΔBW) or waist circumference (ΔWC), and whether the associations were modified by genetic predisposition to a high BMI, WC or waist-hip ratio adjusted for BMI (WHR_BMI). The study was based on 10,898 individuals from the Danish Inter99, the 1958 British Birth Cohort and the Northern Finland Birth Cohort 1966. We combined 42 adiposity-associated Single Nucleotide Polymorphisms (SNPs) into four scores indicating genetic predisposition to BMI, WC and WHR_BMI, or all three traits combined. Linear regression was used to examine the association between serum 25(OH)D and ΔBW or ΔWC, SNP-score × 25(OH)D interactions were examined, and results from the individual cohorts were meta-analyzed. In the meta-analyses, we found no evidence of an association between 25(OH)D and ΔBW (-9.4 gram/y per 10 nmol/L higher 25(OH)D [95% CI: -23.0, +4.3; P = 0.18]) or ΔWC (-0.06 mm/y per 10 nmol/L higher 25(OH)D [95% CI: -0.17, +0.06; P = 0.33]). Furthermore, we found no statistically significant interactions between the four SNP-scores and 25(OH)D in relation to ΔBW or ΔWC. Thus, in view of the narrow CIs, our results suggest that an association between 25(OH)D and changes in measures of adiposity is absent or marginal. Similarly, the study provided evidence that there is either no or very limited dependence on genetic predisposition to adiposity.     

External Morphology of Lophiosilurus alexandri Steindachner, 1876 during Early Stages of Development,and Its Implications for the Evolution of Pseudopimelodidae (Siluriformes)

Pseudopimelodidae are Neotropical catfishes characterized by having slightly to strongly depressed body in fully developed specimens. The largest species of the family with 500 mm SL, Lophiosilurus alexandri, experiences impressive changes in body shape during development, becoming extremely depressed when fully developed. Accordingly, Lophiosilurus alexandri is an ideal species to observe the morphological changes during ontogeny, and to seek solid interpretations on the polarity of characters. Specimens of distinct larval periods (yolk sac, flexion and postflexion; n = 186 specimens) and juvenile stages (n = 20) were analyzed. Changes in body shape, position of mouth and eye, morphology of fins and pigmentation were observed during the development of Lophiosilurus. Larvae (5.7–11.2 mm standard length) had pigmentation concentrated on the head and parts of body, eyes small and pigmented, short barbels, and well-developed finfold. Juveniles (15.9–28.1 mm standard length) had body shape similar to adult, with head depressed and bearing bony ridges, large mouth, dorsally-oriented eyes, small barbels and well-developed shoulder bulges (cleithral width). The greatest morphological changes in the development of L. alexandri occurred during the postflexion larval stage. Relative to standard length, measurements of snout length, head depth and body depth are smaller in juveniles than in larvae, but body width is larger. New interpretations on the phylogenetic characters related to these changes are provided in view of the two alternative hypotheses of the evolution of Pseudopimelodidae.     

1,25(OH)2D3 and calcipotriol (MC903) have similar effects on the induction of osteoclast-like cell formation in human bone marrow cultures

MC903 is a novel analogue of 1,25(OH)2D3 which exhibits similar inhibitory effects on cell proliferation and like, 1,25(OH)2D3, stimulates synthesis of osteoblast specific proteins by osteoblast-like cells in vitro. It is less active than 1,25(OH)2D3 in causing hypercalcemia in vivo. Since 1,25(OH)2D3 is known to stimulate bone resorption and increase the number of osteoclasts in several systems (in vivo and in vitro) we examined the effects of MC903 on the formation of osteoclast-like cells in vitro. As reported previously 1,25(OH)2D3 promoted the formation of multinucleated cells with phenotypic and functional characteristics of osteoclasts from adult human bone-marrow cultures at concentrations between 10(-8)M to 10(-12)M. Higher doses consistently suppressed multinucleated cell formation to values seen in the absence of 1,25(OH)2D3. Cells cultured in the presence of MC903 or for three weeks consistently induced the formation of multinucleated cells at concentrations 10(-8)M to 10(-12)M. As seen with 1,25(OH)2D3, MC903 also inhibited multinucleated cell formation at very high concentrations (10(-6)M). In two separate experiments MC903 appeared to be more potent than 1,25(OH)2D3 at lower concentrations (10(-10)M - 10(-12)M). From this study we conclude that MC903 is at least as potent as 1,25(OH)2D3 in inducing the formation human osteoclast-like cells in vitro. The decreased ability of MC903 to induce hypercalcemia in vivo is not therefore a result of a less marked effect than 1,25(OH)2D3 on the regulation of osteoclast formation.     

Stability and properties of the two-dimensional hexagonal boron nitride monolayer functionalized by hydroxyl (OH) radicals: a theoretical study

Motivated by the great advance in graphene hydroxide—a versatile material with various applications—we performed density functional theory (DFT) calculations to study the functionalization of the two-dimensional hexagonal boron nitride (h-BN) sheet with hydroxyl (OH) radicals, which has been achieved experimentally recently. Particular attention was paid to searching for the most favorable site(s) for the adsorbed OH radicals on a h-BN sheet and addressing the roles of OH radical coverage on the stability and properties of functionalized h-BN sheet. The results indicate that, for an individual OH radica, the most stable configuration is that it is adsorbed on the B site of the h-BN surface with an adsorption energy of ?0.88 eV and a magnetic moment of 1.00 μ_B. Upon adsorption of more than one OH radical on a h-BN sheet, however, these adsorbates prefer to adsorb in pairs on the B and its nearest N atoms from both sides of h-BN sheet without magnetic moment. An energy diagram of the average adsorption energy of OH radicals on h-BN sheet as a function of its coverage indicates that when the OH radical coverage reaches to 60 %, the functionalized h-BN sheet is the most stable among all studied configurations. More importantly, this configuration exhibits good thermal and dynamical stability at room temperature. Owing to the introduction of certain impurity levels, the band gap of h-BN sheet gradually decreases with increasing OH coverage, thereby enhancing its electrical conductivity.

The Paracrine Feedback Loop Between Vitamin D3 (1,25(OH)2D3) and PTHrP in Prehypertrophic Chondrocytes

The endocrine feedback loop between vitamin D₃ (1,25(OH)₂D₃) and parathyroid hormone (PTH) plays a central role in skeletal development. PTH‐related protein (PTHrP) shares homology and its receptor (PTHR1) with PTH. The aim of this study was to investigate whether there is a functional paracrine feedback loop between 1,25(OH)₂D₃ and PTHrP in the growth plate, in parallel with the endocrine feedback loop between 1,25(OH)₂D₃ and PTH. This was investigated in ATDC5 cells treated with 10^?8 M 1,25(OH)₂D₃ or PTHrP, Col2‐pd2EGFP transgenic mice, and primary Col2‐pd2EGFP growth plate chondrocytes isolated by FACS, using RT‐qPCR, Western blot, PTHrP ELISA, chromatin immunoprecipitation (ChIP) assay, silencing of the 1,25(OH)₂D₃ receptor (VDR), immunofluorescent staining, immunohistochemistry, and histomorphometric analysis of the growth plate. The ChIP assay confirmed functional binding of the VDR to the PTHrP promoter, but not to the PTHR1 promoter. Treatment with 1,25(OH)₂D₃ decreased PTHrP protein production, an effect which was prevented by silencing of the VDR. Treatment with PTHrP significantly induced VDR production, but did not affect 1α‐ and 24‐hydroxylase expression. Hypertrophic differentiation was inhibited by PTHrP and 1,25(OH)₂D₃ treatment. Taken together, these findings indicate that there is a functional paracrine feedback loop between 1,25(OH)₂D₃ and PTHrP in the growth plate. 1,25(OH)₂D₃ decreases PTHrP production, while PTHrP increases chondrocyte sensitivity to 1,25(OH)₂D₃ by increasing VDR production. In light of the role of 1,25(OH)₂D₃ and PTHrP in modulating chondrocyte differentiation, 1,25(OH)₂D₃ in addition to PTHrP could potentially be used to prevent undesirable hypertrophic chondrocyte differentiation during cartilage repair or regeneration. J. Cell. Physiol. 229: 1999–2014, 2014. © 2014 Wiley Periodicals, Inc.

     

Relative limb strength and locomotion in Homo habilis

The Homo habilis OH 62 partial skeleton has played an important, although controversial role in interpretations of early Homo locomotor behavior. Past interpretive problems stemmed from uncertain bone length estimates and comparisons using external bone breadth proportions, which do not clearly distinguish between modern humans and apes. Here, true cross-sectional bone strength measurements of the OH 62 femur and humerus are compared with those of modern humans and chimpanzees, as well as two early H. erectus specimens-KNM-WT 15000 and KNM-ER 1808. The comparative sections include two locations in the femur and two in the humerus in order to encompass the range of possible section positions in the OH 62 specimens. For each combination of section locations, femoral to humeral strength proportions of OH 62 fall below the 95% confidence interval of modern humans, and for most comparisons, within the 95% confidence interval of chimpanzees. In contrast, the two H. erectus specimens both fall within or even above the modern human distributions. This indicates that load distribution between the limbs, and by implication, locomotor behavior, was significantly different in H. habilis from that of H. erectus and modern humans. When considered with other postcranial evidence, the most likely interpretation is that H. habilis, although bipedal when terrestrial, still engaged in frequent arboreal behavior, while H. erectus was a completely committed terrestrial biped. This adds to the evidence that H. habilis (sensu stricto) and H. erectus represent ecologically distinct, parallel lineages during the early Pleistocene.